diff --git a/CHANGES.txt b/CHANGES.txt
index 9ac707e..3b0a4f0 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,16 @@
+Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
+  Protocol Compiler
+  * Stop emitting boilerplate {Copy/Merge}From in each ProtoBuf class
+  * split the accessor annotations according to their operation
+  * introduce proto message injector
+  * let proto message injector decide whether to calculate address info based on field descriptor and access type.
+  * Disable LITE_RUNTIME injector annotations
+  * move callback and @protoc_insertion_point after internal set of enum fields
+  * Improve ExtractFieldInfo codegen for string fields with oneof or default value
+  * Rename MessageInjector to FieldAccessListener
+  * Change the API of FieldAccessListener to support callbacks for info extraction
+  * make field_access_injector private
+
 2021-05-07 version 3.17.1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   PHP
   * Fixed PHP memory leaks and arginfo errors. (#8614)
@@ -9,6 +22,7 @@
   * Fixed JSON parser to allow multiple values from the same oneof as long as
     all but one are null.
 
+
 2021-05-07 version 3.17.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
 
   Protocol Compiler
diff --git a/Makefile.am b/Makefile.am
index 8cf5473..573003b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1427,7 +1427,8 @@
   third_party/zlib.BUILD                 \
   third_party/wyhash/LICENSE             \
   third_party/wyhash/wyhash.h            \
-  util/python/BUILD
+  util/python/BUILD                      \
+  internal.bzl
 
 
 # Deletes all the files generated by autogen.sh.
diff --git a/cmake/extract_includes.bat.in b/cmake/extract_includes.bat.in
index ad630af..3e9418c 100644
--- a/cmake/extract_includes.bat.in
+++ b/cmake/extract_includes.bat.in
@@ -51,6 +51,9 @@
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_enum_util.h" include\google\protobuf\generated_enum_util.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_message_reflection.h" include\google\protobuf\generated_message_reflection.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_message_table_driven.h" include\google\protobuf\generated_message_table_driven.h
+copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_message_tctable_decl.h" include\google\protobuf\generated_message_tctable_decl.h
+copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_message_tctable_impl.h" include\google\protobuf\generated_message_tctable_impl.h
+copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_message_tctable_impl.inc" include\google\protobuf\generated_message_tctable_impl.inc
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\generated_message_util.h" include\google\protobuf\generated_message_util.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\has_bits.h" include\google\protobuf\has_bits.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\implicit_weak_message.h" include\google\protobuf\implicit_weak_message.h
diff --git a/conformance/binary_json_conformance_suite.h b/conformance/binary_json_conformance_suite.h
index 0a17526..280ff95 100644
--- a/conformance/binary_json_conformance_suite.h
+++ b/conformance/binary_json_conformance_suite.h
@@ -42,7 +42,7 @@
   BinaryAndJsonConformanceSuite() {}
 
  private:
-  void RunSuiteImpl();
+  void RunSuiteImpl() override;
   void RunJsonTests();
   void RunJsonTestsForFieldNameConvention();
   void RunJsonTestsForNonRepeatedTypes();
diff --git a/conformance/text_format_conformance_suite.h b/conformance/text_format_conformance_suite.h
index d68f4aa..e875f31 100644
--- a/conformance/text_format_conformance_suite.h
+++ b/conformance/text_format_conformance_suite.h
@@ -41,7 +41,7 @@
   TextFormatConformanceTestSuite();
 
  private:
-  void RunSuiteImpl();
+  void RunSuiteImpl() override;
   void RunValidTextFormatTest(const std::string& test_name,
                               ConformanceLevel level, const std::string& input);
   void RunValidTextFormatTestProto2(const std::string& test_name,
diff --git a/docs/options.md b/docs/options.md
index 79a085e..2b7e89c 100644
--- a/docs/options.md
+++ b/docs/options.md
@@ -276,3 +276,7 @@
 1. Kratos API Errors
    * Website: https://go-kratos.dev
    * Extension: 1108
+
+1. Glitchdot (Currently Private)
+   * Website: https://go.glitchdot.com
+   * Extension: 1109
diff --git a/java/kotlin-lite/src/test/kotlin/com/google/protobuf/ExtendableMessageLiteExtensionsTest.kt b/java/kotlin-lite/src/test/kotlin/com/google/protobuf/ExtendableMessageLiteExtensionsTest.kt
index 18933d1..53291b4 100644
--- a/java/kotlin-lite/src/test/kotlin/com/google/protobuf/ExtendableMessageLiteExtensionsTest.kt
+++ b/java/kotlin-lite/src/test/kotlin/com/google/protobuf/ExtendableMessageLiteExtensionsTest.kt
@@ -1,8 +1,38 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.truth.Truth.assertThat
-import example_extensible_message.ExampleExtensibleMessage
-import example_extensible_message.ExampleExtensibleMessageOuterClass as TestProto
+import com.google.protobuf.kotlin.test.ExampleExtensibleMessage
+import com.google.protobuf.kotlin.test.ExampleExtensibleMessageOuterClass as TestProto
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
diff --git a/java/kotlin-lite/src/test/kotlin/com/google/protobuf/Proto2LiteTest.kt b/java/kotlin-lite/src/test/kotlin/com/google/protobuf/Proto2LiteTest.kt
index d78bfff..76d4847 100644
--- a/java/kotlin-lite/src/test/kotlin/com/google/protobuf/Proto2LiteTest.kt
+++ b/java/kotlin-lite/src/test/kotlin/com/google/protobuf/Proto2LiteTest.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.truth.Truth.assertThat
@@ -16,13 +46,13 @@
 import com.google.protobuf.UnittestLite.TestEmptyMessageWithExtensionsLite
 import com.google.protobuf.copy
 import com.google.protobuf.foreignMessageLite
-import evil_names_proto2.EvilNamesProto2OuterClass.EvilNamesProto2
-import evil_names_proto2.EvilNamesProto2OuterClass.HardKeywordsAllTypes
-import evil_names_proto2.EvilNamesProto2OuterClass.Interface
-import evil_names_proto2.HardKeywordsAllTypesKt
-import evil_names_proto2.evilNamesProto2
-import evil_names_proto2.hardKeywordsAllTypes
-import evil_names_proto2.interface_
+import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.EvilNamesProto2
+import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.HardKeywordsAllTypesProto2
+import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.Interface
+import com.google.protobuf.kotlin.generator.HardKeywordsAllTypesProto2Kt
+import com.google.protobuf.kotlin.generator.evilNamesProto2
+import com.google.protobuf.kotlin.generator.hardKeywordsAllTypesProto2
+import com.google.protobuf.kotlin.generator.interface_
 import com.google.protobuf.optionalGroupExtensionLite
 import com.google.protobuf.repeatedGroupExtensionLite
 import com.google.protobuf.testAllExtensionsLite
@@ -918,18 +948,18 @@
 
   @Test
   fun testHardKeywordGettersAndSetters() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto2 {
       as_ = 1
       assertThat(as_).isEqualTo(1)
 
       in_ = "foo"
       assertThat(in_).isEqualTo("foo")
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
-      assertThat(break_).isEqualTo(HardKeywordsAllTypes.NestedEnum.FOO)
+      break_ = HardKeywordsAllTypesProto2.NestedEnum.FOO
+      assertThat(break_).isEqualTo(HardKeywordsAllTypesProto2.NestedEnum.FOO)
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
-      assertThat(do_).isEqualTo(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 })
+      do_ = HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
+      assertThat(do_).isEqualTo(HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 })
 
       continue_[1] = 1
       assertThat(continue_[1]).isEqualTo(1)
@@ -940,34 +970,34 @@
       for_ += "foo"
       assertThat(for_).isEqualTo(listOf("foo"))
 
-      fun_ += HardKeywordsAllTypes.NestedEnum.FOO
-      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypes.NestedEnum.FOO))
+      fun_ += HardKeywordsAllTypesProto2.NestedEnum.FOO
+      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypesProto2.NestedEnum.FOO))
 
-      if_ += HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
-      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }))
+      if_ += HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
+      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }))
     }
   }
 
   @Test
   fun testHardKeywordHazzers() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto2 {
       as_ = 1
       assertThat(hasAs_()).isTrue()
 
       in_ = "foo"
       assertThat(hasIn_()).isTrue()
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      break_ = HardKeywordsAllTypesProto2.NestedEnum.FOO
       assertThat(hasBreak_()).isTrue()
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      do_ = HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
       assertThat(hasDo_()).isTrue()
     }
   }
 
   @Test
   fun testHardKeywordClears() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto2 {
       as_ = 1
       clearAs_()
       assertThat(hasAs_()).isFalse()
@@ -976,11 +1006,11 @@
       clearIn_()
       assertThat(hasIn_()).isFalse()
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      break_ = HardKeywordsAllTypesProto2.NestedEnum.FOO
       clearBreak_()
       assertThat(hasBreak_()).isFalse()
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      do_ = HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
       clearDo_()
       assertThat(hasDo_()).isFalse()
     }
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/DslList.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/DslList.kt
index 54a64af..9f7f75b 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/DslList.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/DslList.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 /**
@@ -25,3 +55,5 @@
 
   override fun toString(): String = delegate.toString()
 }
+
+// TODO(lowasser): investigate making this an inline class
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/DslMap.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/DslMap.kt
index 9949fb4..d35195e 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/DslMap.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/DslMap.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 /**
@@ -28,3 +58,5 @@
 
   override fun toString(): String = delegate.toString()
 }
+
+// TODO(lowasser): investigate making this an inline class
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/DslProxy.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/DslProxy.kt
index 7d14e95..c9b2dd4 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/DslProxy.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/DslProxy.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 /**
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageExtensions.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageExtensions.kt
index 10630a9..4f64843 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageExtensions.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageExtensions.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.protobuf.ExtensionLite
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageLiteExtensions.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageLiteExtensions.kt
index dd1dc87..6c208b2 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageLiteExtensions.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/ExtendableMessageLiteExtensions.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.protobuf.ExtensionLite
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/ExtensionList.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/ExtensionList.kt
index 03764e1..37e958e 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/ExtensionList.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/ExtensionList.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.protobuf.ExtensionLite
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt
index 368912e..c8ed63d 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 /**
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/ProtoDslMarker.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/ProtoDslMarker.kt
index c51ba35..e922624 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/ProtoDslMarker.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/ProtoDslMarker.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 /**
diff --git a/java/kotlin/src/main/kotlin/com/google/protobuf/UnmodifiableCollections.kt b/java/kotlin/src/main/kotlin/com/google/protobuf/UnmodifiableCollections.kt
index 6af93e1..cf45e89 100644
--- a/java/kotlin/src/main/kotlin/com/google/protobuf/UnmodifiableCollections.kt
+++ b/java/kotlin/src/main/kotlin/com/google/protobuf/UnmodifiableCollections.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 /** Wraps an [Iterator] and makes it unmodifiable even from Java. */
diff --git a/java/kotlin/src/test/kotlin/com/google/protobuf/DslListTest.kt b/java/kotlin/src/test/kotlin/com/google/protobuf/DslListTest.kt
index e5e6017..a5f0c49 100644
--- a/java/kotlin/src/test/kotlin/com/google/protobuf/DslListTest.kt
+++ b/java/kotlin/src/test/kotlin/com/google/protobuf/DslListTest.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.testing.EqualsTester
diff --git a/java/kotlin/src/test/kotlin/com/google/protobuf/DslMapTest.kt b/java/kotlin/src/test/kotlin/com/google/protobuf/DslMapTest.kt
index 470e42e..e7f7a19 100644
--- a/java/kotlin/src/test/kotlin/com/google/protobuf/DslMapTest.kt
+++ b/java/kotlin/src/test/kotlin/com/google/protobuf/DslMapTest.kt
@@ -1,3 +1,33 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.testing.EqualsTester
diff --git a/java/kotlin/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt b/java/kotlin/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt
index c8816eb..623bc58 100644
--- a/java/kotlin/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt
+++ b/java/kotlin/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt
@@ -1,8 +1,38 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.truth.Truth.assertThat
-import example_extensible_message.ExampleExtensibleMessage
-import example_extensible_message.ExampleExtensibleMessageOuterClass as TestProto
+import com.google.protobuf.kotlin.test.ExampleExtensibleMessage
+import com.google.protobuf.kotlin.test.ExampleExtensibleMessageOuterClass as TestProto
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
diff --git a/java/kotlin/src/test/kotlin/com/google/protobuf/ExtensionListTest.kt b/java/kotlin/src/test/kotlin/com/google/protobuf/ExtensionListTest.kt
index e805e1e..239f27a 100644
--- a/java/kotlin/src/test/kotlin/com/google/protobuf/ExtensionListTest.kt
+++ b/java/kotlin/src/test/kotlin/com/google/protobuf/ExtensionListTest.kt
@@ -1,9 +1,39 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.testing.EqualsTester
 import com.google.common.truth.Truth.assertThat
-import example_extensible_message.ExampleExtensibleMessage
-import example_extensible_message.ExampleExtensibleMessageOuterClass as TestProto
+import com.google.protobuf.kotlin.test.ExampleExtensibleMessage
+import com.google.protobuf.kotlin.test.ExampleExtensibleMessageOuterClass as TestProto
 import kotlin.test.assertFailsWith
 import org.junit.Test
 import org.junit.runner.RunWith
diff --git a/java/kotlin/src/test/kotlin/com/google/protobuf/Proto2Test.kt b/java/kotlin/src/test/kotlin/com/google/protobuf/Proto2Test.kt
index 62b9899..65f0324 100644
--- a/java/kotlin/src/test/kotlin/com/google/protobuf/Proto2Test.kt
+++ b/java/kotlin/src/test/kotlin/com/google/protobuf/Proto2Test.kt
@@ -1,15 +1,45 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.truth.Truth.assertThat
 import com.google.protobuf.TestUtil
 import com.google.protobuf.TestUtil.toBytes
-import evil_names_proto2.EvilNamesProto2OuterClass.EvilNamesProto2
-import evil_names_proto2.EvilNamesProto2OuterClass.HardKeywordsAllTypes
-import evil_names_proto2.EvilNamesProto2OuterClass.Interface
-import evil_names_proto2.HardKeywordsAllTypesKt
-import evil_names_proto2.evilNamesProto2
-import evil_names_proto2.hardKeywordsAllTypes
-import evil_names_proto2.interface_
+import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.EvilNamesProto2
+import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.HardKeywordsAllTypesProto2
+import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.Interface
+import com.google.protobuf.kotlin.generator.HardKeywordsAllTypesProto2Kt
+import com.google.protobuf.kotlin.generator.evilNamesProto2
+import com.google.protobuf.kotlin.generator.hardKeywordsAllTypesProto2
+import com.google.protobuf.kotlin.generator.interface_
 import com.google.protobuf.test.UnittestImport.ImportEnum
 import com.google.protobuf.test.UnittestImport.ImportMessage
 import com.google.protobuf.test.UnittestImportPublic.PublicImportMessage
@@ -910,18 +940,18 @@
 
   @Test
   fun testHardKeywordGettersAndSetters() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto2 {
       as_ = 1
       assertThat(as_).isEqualTo(1)
 
       in_ = "foo"
       assertThat(in_).isEqualTo("foo")
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
-      assertThat(break_).isEqualTo(HardKeywordsAllTypes.NestedEnum.FOO)
+      break_ = HardKeywordsAllTypesProto2.NestedEnum.FOO
+      assertThat(break_).isEqualTo(HardKeywordsAllTypesProto2.NestedEnum.FOO)
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
-      assertThat(do_).isEqualTo(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 })
+      do_ = HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
+      assertThat(do_).isEqualTo(HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 })
 
       continue_[1] = 1
       assertThat(continue_[1]).isEqualTo(1)
@@ -932,34 +962,34 @@
       for_ += "foo"
       assertThat(for_).isEqualTo(listOf("foo"))
 
-      fun_ += HardKeywordsAllTypes.NestedEnum.FOO
-      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypes.NestedEnum.FOO))
+      fun_ += HardKeywordsAllTypesProto2.NestedEnum.FOO
+      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypesProto2.NestedEnum.FOO))
 
-      if_ += HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
-      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }))
+      if_ += HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
+      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }))
     }
   }
 
   @Test
   fun testHardKeywordHazzers() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto2 {
       as_ = 1
       assertThat(hasAs_()).isTrue()
 
       in_ = "foo"
       assertThat(hasIn_()).isTrue()
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      break_ = HardKeywordsAllTypesProto2.NestedEnum.FOO
       assertThat(hasBreak_()).isTrue()
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      do_ = HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
       assertThat(hasDo_()).isTrue()
     }
   }
 
   @Test
   fun testHardKeywordClears() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto2 {
       as_ = 1
       clearAs_()
       assertThat(hasAs_()).isFalse()
@@ -968,11 +998,11 @@
       clearIn_()
       assertThat(hasIn_()).isFalse()
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      break_ = HardKeywordsAllTypesProto2.NestedEnum.FOO
       clearBreak_()
       assertThat(hasBreak_()).isFalse()
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      do_ = HardKeywordsAllTypesProto2Kt.nestedMessage { while_ = 1 }
       clearDo_()
       assertThat(hasDo_()).isFalse()
     }
diff --git a/java/kotlin/src/test/kotlin/com/google/protobuf/Proto3Test.kt b/java/kotlin/src/test/kotlin/com/google/protobuf/Proto3Test.kt
index b3fd336..7b394da 100644
--- a/java/kotlin/src/test/kotlin/com/google/protobuf/Proto3Test.kt
+++ b/java/kotlin/src/test/kotlin/com/google/protobuf/Proto3Test.kt
@@ -1,18 +1,43 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package com.google.protobuf.kotlin
 
 import com.google.common.truth.Truth.assertThat
-import evil_names_proto3.EvilNamesProto3OuterClass.EvilNamesProto3
-import evil_names_proto3.EvilNamesProto3OuterClass.HardKeywordsAllTypes
-import evil_names_proto3.EvilNamesProto3OuterClass.Class
-import evil_names_proto3.HardKeywordsAllTypesKt
-import evil_names_proto3.class_
-import evil_names_proto3.evilNamesProto3
-import evil_names_proto3.hardKeywordsAllTypes
-import multiple_files_proto3.MultipleFilesMessageA
-import multiple_files_proto3.MultipleFilesMessageB
-import multiple_files_proto3.multipleFilesMessageA
-import multiple_files_proto3.multipleFilesMessageB
-import proto3_unittest.UnittestProto3
+import com.google.protobuf.kotlin.generator.EvilNamesProto3OuterClass.Class
+import com.google.protobuf.kotlin.generator.EvilNamesProto3OuterClass.EvilNamesProto3
+import com.google.protobuf.kotlin.generator.EvilNamesProto3OuterClass.HardKeywordsAllTypesProto3
+import com.google.protobuf.kotlin.generator.HardKeywordsAllTypesProto3Kt
+import com.google.protobuf.kotlin.generator.class_
+import com.google.protobuf.kotlin.generator.evilNamesProto3
+import com.google.protobuf.kotlin.generator.hardKeywordsAllTypesProto3
 import proto3_unittest.TestAllTypesKt
 import proto3_unittest.TestAllTypesKt.nestedMessage
 import proto3_unittest.UnittestProto3.TestAllTypes
@@ -255,18 +280,18 @@
 
   @Test
   fun testHardKeywordGettersAndSetters() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto3 {
       as_ = 1
       assertThat(as_).isEqualTo(1)
 
       in_ = "foo"
       assertThat(in_).isEqualTo("foo")
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
-      assertThat(break_).isEqualTo(HardKeywordsAllTypes.NestedEnum.FOO)
+      break_ = HardKeywordsAllTypesProto3.NestedEnum.FOO
+      assertThat(break_).isEqualTo(HardKeywordsAllTypesProto3.NestedEnum.FOO)
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
-      assertThat(do_).isEqualTo(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 })
+      do_ = HardKeywordsAllTypesProto3Kt.nestedMessage { while_ = 1 }
+      assertThat(do_).isEqualTo(HardKeywordsAllTypesProto3Kt.nestedMessage { while_ = 1 })
 
       continue_[1] = 1
       assertThat(continue_[1]).isEqualTo(1)
@@ -277,34 +302,34 @@
       for_ += "foo"
       assertThat(for_).isEqualTo(listOf("foo"))
 
-      fun_ += HardKeywordsAllTypes.NestedEnum.FOO
-      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypes.NestedEnum.FOO))
+      fun_ += HardKeywordsAllTypesProto3.NestedEnum.FOO
+      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypesProto3.NestedEnum.FOO))
 
-      if_ += HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
-      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }))
+      if_ += HardKeywordsAllTypesProto3Kt.nestedMessage { while_ = 1 }
+      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesProto3Kt.nestedMessage { while_ = 1 }))
     }
   }
 
   @Test
   fun testHardKeywordHazzers() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto3 {
       as_ = 1
       assertThat(hasAs_()).isTrue()
 
       in_ = "foo"
       assertThat(hasIn_()).isTrue()
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      break_ = HardKeywordsAllTypesProto3.NestedEnum.FOO
       assertThat(hasBreak_()).isTrue()
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      do_ = HardKeywordsAllTypesProto3Kt.nestedMessage { while_ = 1 }
       assertThat(hasDo_()).isTrue()
     }
   }
 
   @Test
   fun testHardKeywordClears() {
-    hardKeywordsAllTypes {
+    hardKeywordsAllTypesProto3 {
       as_ = 1
       clearAs_()
       assertThat(hasAs_()).isFalse()
@@ -313,11 +338,11 @@
       clearIn_()
       assertThat(hasIn_()).isFalse()
 
-      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      break_ = HardKeywordsAllTypesProto3.NestedEnum.FOO
       clearBreak_()
       assertThat(hasBreak_()).isFalse()
 
-      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      do_ = HardKeywordsAllTypesProto3Kt.nestedMessage { while_ = 1 }
       clearDo_()
       assertThat(hasDo_()).isFalse()
     }
@@ -326,15 +351,15 @@
   @Test
   fun testMultipleFiles() {
     assertThat(
-      multipleFilesMessageA {}
+      com.google.protobuf.kotlin.generator.multipleFilesMessageA {}
     ).isEqualTo(
-      MultipleFilesMessageA.newBuilder().build()
+      com.google.protobuf.kotlin.generator.MultipleFilesMessageA.newBuilder().build()
     )
 
     assertThat(
-      multipleFilesMessageB {}
+      com.google.protobuf.kotlin.generator.multipleFilesMessageB {}
     ).isEqualTo(
-      MultipleFilesMessageB.newBuilder().build()
+      com.google.protobuf.kotlin.generator.MultipleFilesMessageB.newBuilder().build()
     )
   }
 }
diff --git a/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto2.proto b/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto2.proto
index 70d813a..3735baf 100644
--- a/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto2.proto
+++ b/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto2.proto
@@ -1,8 +1,39 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// LINT: LEGACY_NAMES
 syntax = "proto2";
 
-package evil_names_proto2;
+package protobuf.kotlin.generator;
 
-option java_package = "evil_names_proto2";
+option java_package = "com.google.protobuf.kotlin.generator";
 
 message EvilNamesProto2 {
   optional bool initialized = 1;
@@ -37,7 +68,7 @@
   optional string by = 25;
 }
 
-message HardKeywordsAllTypes {
+message HardKeywordsAllTypesProto2 {
   message NestedMessage {
     optional int32 while = 1;
   }
diff --git a/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto3.proto b/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto3.proto
index 1b40e4d..f6b06d3 100644
--- a/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto3.proto
+++ b/java/kotlin/src/test/proto/com/google/protobuf/evil_names_proto3.proto
@@ -1,8 +1,39 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// LINT: LEGACY_NAMES
 syntax = "proto3";
 
-package evil_names_proto3;
+package protobuf.kotlin.generator;
 
-option java_package = "evil_names_proto3";
+option java_package = "com.google.protobuf.kotlin.generator";
 
 message EvilNamesProto3 {
   bool initialized = 1;
@@ -50,7 +81,7 @@
   }
 }
 
-message HardKeywordsAllTypes {
+message HardKeywordsAllTypesProto3 {
   message NestedMessage {
     optional int32 while = 1;
   }
diff --git a/java/kotlin/src/test/proto/com/google/protobuf/example_extensible_message.proto b/java/kotlin/src/test/proto/com/google/protobuf/example_extensible_message.proto
index 14f18db..b82c82b 100644
--- a/java/kotlin/src/test/proto/com/google/protobuf/example_extensible_message.proto
+++ b/java/kotlin/src/test/proto/com/google/protobuf/example_extensible_message.proto
@@ -1,8 +1,38 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto2";
 
-package example_extensible_message;
+package protobuf.kotlin.test;
 
-option java_package = "example_extensible_message";
+option java_package = "com.google.protobuf.kotlin.test";
 option java_multiple_files = true;
 
 message ExampleExtensibleMessage {
diff --git a/java/kotlin/src/test/proto/com/google/protobuf/multiple_files_proto3.proto b/java/kotlin/src/test/proto/com/google/protobuf/multiple_files_proto3.proto
index 82211cc..61141c5 100644
--- a/java/kotlin/src/test/proto/com/google/protobuf/multiple_files_proto3.proto
+++ b/java/kotlin/src/test/proto/com/google/protobuf/multiple_files_proto3.proto
@@ -1,8 +1,38 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
-package multiple_files_proto3;
+package protobuf.kotlin.generator;
 
-option java_package = "multiple_files_proto3";
+option java_package = "com.google.protobuf.kotlin.generator";
 option java_multiple_files = true;
 
 enum NestedEnum { FOO = 0; }
diff --git a/java/util/src/main/java/com/google/protobuf/util/JsonFormat.java b/java/util/src/main/java/com/google/protobuf/util/JsonFormat.java
index 4f2fe3f..2383da6 100644
--- a/java/util/src/main/java/com/google/protobuf/util/JsonFormat.java
+++ b/java/util/src/main/java/com/google/protobuf/util/JsonFormat.java
@@ -1295,7 +1295,6 @@
   private static class ParserImpl {
     private final com.google.protobuf.TypeRegistry registry;
     private final TypeRegistry oldRegistry;
-    private final JsonParser jsonParser;
     private final boolean ignoringUnknownFields;
     private final int recursionLimit;
     private int currentDepth;
@@ -1308,7 +1307,6 @@
       this.registry = registry;
       this.oldRegistry = oldRegistry;
       this.ignoringUnknownFields = ignoreUnknownFields;
-      this.jsonParser = new JsonParser();
       this.recursionLimit = recursionLimit;
       this.currentDepth = 0;
     }
@@ -1317,7 +1315,7 @@
       try {
         JsonReader reader = new JsonReader(json);
         reader.setLenient(false);
-        merge(jsonParser.parse(reader), builder);
+        merge(JsonParser.parseReader(reader), builder);
       } catch (InvalidProtocolBufferException e) {
         throw e;
       } catch (JsonIOException e) {
@@ -1337,7 +1335,7 @@
       try {
         JsonReader reader = new JsonReader(new StringReader(json));
         reader.setLenient(false);
-        merge(jsonParser.parse(reader), builder);
+        merge(JsonParser.parseReader(reader), builder);
       } catch (InvalidProtocolBufferException e) {
         throw e;
       } catch (Exception e) {
diff --git a/kokoro/linux/dockerfile/test/javascript/Dockerfile b/kokoro/linux/dockerfile/test/javascript/Dockerfile
index dff7e7b..184828f 100644
--- a/kokoro/linux/dockerfile/test/javascript/Dockerfile
+++ b/kokoro/linux/dockerfile/test/javascript/Dockerfile
@@ -27,7 +27,11 @@
 
 ##################
 # Javascript dependencies.
-RUN apt-get install -y \
+# We need to set these environment variables so that the Docker build does not
+# have to ask for this information while it is installing the tzdata package.
+RUN DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles" \
+  apt-get install -y \
   # -- For javascript and closure compiler -- \
   npm \
-  default-jre
+  default-jre \
+  python
diff --git a/objectivec/GPBDescriptor.h b/objectivec/GPBDescriptor.h
index 331d444..fd66b0e 100644
--- a/objectivec/GPBDescriptor.h
+++ b/objectivec/GPBDescriptor.h
@@ -182,7 +182,7 @@
 @property(nonatomic, readonly, getter=isOptional) BOOL optional;
 /** Type of field (single, repeated, map). */
 @property(nonatomic, readonly) GPBFieldType fieldType;
-/** Type of the key if the field is a map. The value's type is -fieldType. */
+/** Type of the key if the field is a map. The value's type is -dataType. */
 @property(nonatomic, readonly) GPBDataType mapKeyDataType;
 /** Whether the field is packable. */
 @property(nonatomic, readonly, getter=isPackable) BOOL packable;
diff --git a/objectivec/Tests/GPBDescriptorTests.m b/objectivec/Tests/GPBDescriptorTests.m
index 6fa7202..bdcc2e8 100644
--- a/objectivec/Tests/GPBDescriptorTests.m
+++ b/objectivec/Tests/GPBDescriptorTests.m
@@ -305,7 +305,7 @@
   GPBDescriptor *descriptor = [TestOneof2 descriptor];
 
   // All fields should be listed.
-  XCTAssertEqual(descriptor.fields.count, 17U);
+  XCTAssertEqual(descriptor.fields.count, 21U);
 
   // There are two oneofs in there.
   XCTAssertEqual(descriptor.oneofs.count, 2U);
@@ -330,7 +330,7 @@
 
   GPBOneofDescriptor *oneofBar = [descriptor oneofWithName:@"bar"];
   XCTAssertNotNil(oneofBar);
-  XCTAssertEqual(oneofBar.fields.count, 6U);
+  XCTAssertEqual(oneofBar.fields.count, 10U);
 
   // Pointer comparisons.
   XCTAssertEqual([oneofBar fieldWithNumber:TestOneof2_FieldNumber_BarString],
diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index f30c6ba..55a5f74 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -103,6 +103,15 @@
 namespace protobuf {
 namespace python {
 
+class MessageReflectionFriend {
+ public:
+  static void UnsafeShallowSwapFields(
+      Message* lhs, Message* rhs,
+      const std::vector<const FieldDescriptor*>& fields) {
+    lhs->GetReflection()->UnsafeShallowSwapFields(lhs, rhs, fields);
+  }
+};
+
 static PyObject* kDESCRIPTOR;
 PyObject* EnumTypeWrapper_class;
 static PyObject* PythonMessage_class;
@@ -1280,7 +1289,7 @@
   if (self == nullptr) {
     return nullptr;
   }
-  self->message = prototype->New();
+  self->message = prototype->New(nullptr);  // Ensures no arena is used.
   self->parent = nullptr;  // This message owns its data.
   return self;
 }
@@ -1525,7 +1534,7 @@
   if (new_message == nullptr) {
     return -1;
   }
-  new_message->message = self->message->New();
+  new_message->message = self->message->New(nullptr);
   ScopedPyObjectPtr holder(reinterpret_cast<PyObject*>(new_message));
   new_message->child_submessages = new CMessage::SubMessagesMap();
   new_message->composite_fields = new CMessage::CompositeFieldsMap();
@@ -1555,7 +1564,9 @@
                                            to_release);
   }
 
-  self->message->GetReflection()->SwapFields(
+  GOOGLE_CHECK_EQ(self->message->GetArena(), new_message->message->GetArena());
+
+  MessageReflectionFriend::UnsafeShallowSwapFields(
       self->message, new_message->message,
       std::vector<const FieldDescriptor*>(fields_to_swap.begin(),
                                           fields_to_swap.end()));
@@ -2689,7 +2700,7 @@
 PyObject* ContainerBase::DeepCopy() {
   CMessage* new_parent =
       cmessage::NewEmptyMessage(this->parent->GetMessageClass());
-  new_parent->message = this->parent->message->New();
+  new_parent->message = this->parent->message->New(nullptr);
 
   // Copy the map field into the new message.
   this->parent->message->GetReflection()->SwapFields(
diff --git a/python/setup.py b/python/setup.py
index ff67b89..aab240a 100755
--- a/python/setup.py
+++ b/python/setup.py
@@ -18,7 +18,6 @@
 
 from distutils.command.build_py import build_py as _build_py
 from distutils.command.clean import clean as _clean
-from distutils.command.build_ext import build_ext as _build_ext
 from distutils.spawn import find_executable
 
 # Find the Protocol Compiler.
@@ -158,22 +157,6 @@
             if not any(fnmatch.fnmatchcase(fil, pat=pat) for pat in exclude)]
 
 
-class build_ext(_build_ext):
-  def get_ext_filename(self, ext_name):
-      # since python3.5, python extensions' shared libraries use a suffix that corresponds to the value
-      # of sysconfig.get_config_var('EXT_SUFFIX') and contains info about the architecture the library targets.
-      # E.g. on x64 linux the suffix is ".cpython-XYZ-x86_64-linux-gnu.so"
-      # When crosscompiling python wheels, we need to be able to override this suffix
-      # so that the resulting file name matches the target architecture and we end up with a well-formed
-      # wheel.
-      filename = _build_ext.get_ext_filename(self, ext_name)
-      orig_ext_suffix = sysconfig.get_config_var("EXT_SUFFIX")
-      new_ext_suffix = os.getenv("PROTOCOL_BUFFERS_OVERRIDE_EXT_SUFFIX")
-      if new_ext_suffix and filename.endswith(orig_ext_suffix):
-        filename = filename[:-len(orig_ext_suffix)] + new_ext_suffix
-      return filename
-
-
 class test_conformance(_build_py):
   target = 'test_python'
   def run(self):
@@ -209,18 +192,6 @@
 
     extra_compile_args = []
 
-    message_extra_link_args = None
-    api_implementation_link_args = None
-    if "darwin" in sys.platform:
-      if sys.version_info[0] == 2:
-          message_init_symbol = 'init_message'
-          api_implementation_init_symbol = 'init_api_implementation'
-      else:
-          message_init_symbol = 'PyInit__message'
-          api_implementation_init_symbol = 'PyInit__api_implementation'
-      message_extra_link_args = ['-Wl,-exported_symbol,_%s' % message_init_symbol]
-      api_implementation_link_args = ['-Wl,-exported_symbol,_%s' % api_implementation_init_symbol]
-
     if sys.platform != 'win32':
         extra_compile_args.append('-Wno-write-strings')
         extra_compile_args.append('-Wno-invalid-offsetof')
@@ -271,7 +242,6 @@
             include_dirs=[".", "../src"],
             libraries=libraries,
             extra_objects=extra_objects,
-            extra_link_args=message_extra_link_args,
             library_dirs=['../src/.libs'],
             extra_compile_args=extra_compile_args,
         ),
@@ -279,7 +249,6 @@
             "google.protobuf.internal._api_implementation",
             glob.glob('google/protobuf/internal/api_implementation.cc'),
             extra_compile_args=extra_compile_args + ['-DPYTHON_PROTO2_CPP_IMPL_V2'],
-            extra_link_args=api_implementation_link_args,
         ),
     ])
     os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION'] = 'cpp'
@@ -322,7 +291,6 @@
       cmdclass={
           'clean': clean,
           'build_py': build_py,
-          'build_ext': build_ext,
           'test_conformance': test_conformance,
       },
       install_requires=install_requires,
diff --git a/src/Makefile.am b/src/Makefile.am
index 12eb707..735e3b8 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -100,6 +100,9 @@
   google/protobuf/generated_enum_util.h                          \
   google/protobuf/generated_message_reflection.h                 \
   google/protobuf/generated_message_table_driven.h               \
+  google/protobuf/generated_message_tctable_decl.h               \
+  google/protobuf/generated_message_tctable_impl.h               \
+  google/protobuf/generated_message_tctable_impl.inc             \
   google/protobuf/generated_message_util.h                       \
   google/protobuf/has_bits.h                                     \
   google/protobuf/implicit_weak_message.h                        \
@@ -889,7 +892,9 @@
 no_warning_test.cc:
 	echo "// Generated from Makefile.am" > no_warning_test.cc
 	for FILE in $(nobase_include_HEADERS); do \
-    echo "#include <$${FILE}>" >> no_warning_test.cc; \
+          if [[ $$FILE != *.inc ]]; then \
+	    echo "#include <$${FILE}>" >> no_warning_test.cc; \
+	  fi \
 	done
 	echo "int main(int, char**) { return 0; }" >> no_warning_test.cc
 
diff --git a/src/google/protobuf/any.pb.cc b/src/google/protobuf/any.pb.cc
index 867cc37..76be849 100644
--- a/src/google/protobuf/any.pb.cc
+++ b/src/google/protobuf/any.pb.cc
@@ -96,11 +96,14 @@
  public:
 };
 
-Any::Any(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Any::Any(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _any_metadata_(&type_url_, &value_) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Any)
 }
 Any::Any(const Any& from)
@@ -120,18 +123,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Any)
 }
 
-void Any::SharedCtor() {
+inline void Any::SharedCtor() {
 type_url_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 value_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
 
 Any::~Any() {
   // @@protoc_insertion_point(destructor:google.protobuf.Any)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Any::SharedDtor() {
+inline void Any::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   type_url_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -265,25 +269,22 @@
   return total_size;
 }
 
-void Any::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Any)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Any* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Any>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Any)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Any)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Any::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Any::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Any::GetClassData() const { return &_class_data_; }
+
+void Any::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Any *>(to)->MergeFrom(
+      static_cast<const Any &>(from));
 }
 
+
 void Any::MergeFrom(const Any& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Any)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -293,13 +294,7 @@
   if (!from.value().empty()) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void Any::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Any)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Any::CopyFrom(const Any& from) {
diff --git a/src/google/protobuf/any.pb.h b/src/google/protobuf/any.pb.h
index 8dc01ca..7b0ae40 100644
--- a/src/google/protobuf/any.pb.h
+++ b/src/google/protobuf/any.pb.h
@@ -170,10 +170,13 @@
   Any* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Any>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Any& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Any& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -193,12 +196,16 @@
     return "google.protobuf.Any";
   }
   protected:
-  explicit Any(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Any(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -215,7 +222,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_type_url(ArgT0&& arg0, ArgT... args);
   std::string* mutable_type_url();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_type_url();
+  PROTOBUF_MUST_USE_RESULT std::string* release_type_url();
   void set_allocated_type_url(std::string* type_url);
   private:
   const std::string& _internal_type_url() const;
@@ -229,7 +236,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_value();
   void set_allocated_value(std::string* value);
   private:
   const std::string& _internal_value() const;
@@ -277,8 +284,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Any.type_url)
 }
 inline std::string* Any::mutable_type_url() {
+  std::string* _s = _internal_mutable_type_url();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Any.type_url)
-  return _internal_mutable_type_url();
+  return _s;
 }
 inline const std::string& Any::_internal_type_url() const {
   return type_url_.Get();
@@ -322,8 +330,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Any.value)
 }
 inline std::string* Any::mutable_value() {
+  std::string* _s = _internal_mutable_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Any.value)
-  return _internal_mutable_value();
+  return _s;
 }
 inline const std::string& Any::_internal_value() const {
   return value_.Get();
diff --git a/src/google/protobuf/api.pb.cc b/src/google/protobuf/api.pb.cc
index 1879c60..35deae3 100644
--- a/src/google/protobuf/api.pb.cc
+++ b/src/google/protobuf/api.pb.cc
@@ -178,13 +178,16 @@
   }
   source_context_ = nullptr;
 }
-Api::Api(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Api::Api(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   methods_(arena),
   options_(arena),
   mixins_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Api)
 }
 Api::Api(const Api& from)
@@ -212,7 +215,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Api)
 }
 
-void Api::SharedCtor() {
+inline void Api::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 version_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
@@ -223,11 +226,12 @@
 
 Api::~Api() {
   // @@protoc_insertion_point(destructor:google.protobuf.Api)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Api::SharedDtor() {
+inline void Api::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   version_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -499,25 +503,22 @@
   return total_size;
 }
 
-void Api::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Api)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Api* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Api>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Api)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Api)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Api::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Api::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Api::GetClassData() const { return &_class_data_; }
+
+void Api::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Api *>(to)->MergeFrom(
+      static_cast<const Api &>(from));
 }
 
+
 void Api::MergeFrom(const Api& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Api)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -536,13 +537,7 @@
   if (from.syntax() != 0) {
     _internal_set_syntax(from._internal_syntax());
   }
-}
-
-void Api::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Api)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Api::CopyFrom(const Api& from) {
@@ -595,11 +590,14 @@
 void Method::clear_options() {
   options_.Clear();
 }
-Method::Method(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Method::Method(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   options_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Method)
 }
 Method::Method(const Method& from)
@@ -627,7 +625,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Method)
 }
 
-void Method::SharedCtor() {
+inline void Method::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 request_type_url_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 response_type_url_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -639,11 +637,12 @@
 
 Method::~Method() {
   // @@protoc_insertion_point(destructor:google.protobuf.Method)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Method::SharedDtor() {
+inline void Method::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   request_type_url_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -898,25 +897,22 @@
   return total_size;
 }
 
-void Method::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Method)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Method* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Method>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Method)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Method)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Method::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Method::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Method::GetClassData() const { return &_class_data_; }
+
+void Method::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Method *>(to)->MergeFrom(
+      static_cast<const Method &>(from));
 }
 
+
 void Method::MergeFrom(const Method& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Method)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -939,13 +935,7 @@
   if (from.syntax() != 0) {
     _internal_set_syntax(from._internal_syntax());
   }
-}
-
-void Method::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Method)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Method::CopyFrom(const Method& from) {
@@ -998,10 +988,13 @@
  public:
 };
 
-Mixin::Mixin(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Mixin::Mixin(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Mixin)
 }
 Mixin::Mixin(const Mixin& from)
@@ -1020,18 +1013,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Mixin)
 }
 
-void Mixin::SharedCtor() {
+inline void Mixin::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 root_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
 
 Mixin::~Mixin() {
   // @@protoc_insertion_point(destructor:google.protobuf.Mixin)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Mixin::SharedDtor() {
+inline void Mixin::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   root_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -1170,25 +1164,22 @@
   return total_size;
 }
 
-void Mixin::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Mixin)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Mixin* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Mixin>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Mixin)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Mixin)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Mixin::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Mixin::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Mixin::GetClassData() const { return &_class_data_; }
+
+void Mixin::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Mixin *>(to)->MergeFrom(
+      static_cast<const Mixin &>(from));
 }
 
+
 void Mixin::MergeFrom(const Mixin& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Mixin)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -1198,13 +1189,7 @@
   if (!from.root().empty()) {
     _internal_set_root(from._internal_root());
   }
-}
-
-void Mixin::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Mixin)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Mixin::CopyFrom(const Mixin& from) {
diff --git a/src/google/protobuf/api.pb.h b/src/google/protobuf/api.pb.h
index 1f92d43..e4fd56c 100644
--- a/src/google/protobuf/api.pb.h
+++ b/src/google/protobuf/api.pb.h
@@ -147,10 +147,13 @@
   Api* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Api>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Api& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Api& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -170,12 +173,16 @@
     return "google.protobuf.Api";
   }
   protected:
-  explicit Api(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Api(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -251,7 +258,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -265,7 +272,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_version(ArgT0&& arg0, ArgT... args);
   std::string* mutable_version();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_version();
+  PROTOBUF_MUST_USE_RESULT std::string* release_version();
   void set_allocated_version(std::string* version);
   private:
   const std::string& _internal_version() const;
@@ -280,7 +287,7 @@
   public:
   void clear_source_context();
   const PROTOBUF_NAMESPACE_ID::SourceContext& source_context() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceContext* release_source_context();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceContext* release_source_context();
   PROTOBUF_NAMESPACE_ID::SourceContext* mutable_source_context();
   void set_allocated_source_context(PROTOBUF_NAMESPACE_ID::SourceContext* source_context);
   private:
@@ -391,10 +398,13 @@
   Method* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Method>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Method& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Method& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -414,12 +424,16 @@
     return "google.protobuf.Method";
   }
   protected:
-  explicit Method(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Method(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -459,7 +473,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -473,7 +487,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_request_type_url(ArgT0&& arg0, ArgT... args);
   std::string* mutable_request_type_url();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_request_type_url();
+  PROTOBUF_MUST_USE_RESULT std::string* release_request_type_url();
   void set_allocated_request_type_url(std::string* request_type_url);
   private:
   const std::string& _internal_request_type_url() const;
@@ -487,7 +501,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_response_type_url(ArgT0&& arg0, ArgT... args);
   std::string* mutable_response_type_url();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_response_type_url();
+  PROTOBUF_MUST_USE_RESULT std::string* release_response_type_url();
   void set_allocated_response_type_url(std::string* response_type_url);
   private:
   const std::string& _internal_response_type_url() const;
@@ -613,10 +627,13 @@
   Mixin* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Mixin>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Mixin& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Mixin& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -636,12 +653,16 @@
     return "google.protobuf.Mixin";
   }
   protected:
-  explicit Mixin(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Mixin(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -658,7 +679,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -672,7 +693,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_root(ArgT0&& arg0, ArgT... args);
   std::string* mutable_root();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_root();
+  PROTOBUF_MUST_USE_RESULT std::string* release_root();
   void set_allocated_root(std::string* root);
   private:
   const std::string& _internal_root() const;
@@ -719,8 +740,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Api.name)
 }
 inline std::string* Api::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Api.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Api::_internal_name() const {
   return name_.Get();
@@ -778,8 +800,9 @@
   return methods_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Method* Api::add_methods() {
+  PROTOBUF_NAMESPACE_ID::Method* _add = _internal_add_methods();
   // @@protoc_insertion_point(field_add:google.protobuf.Api.methods)
-  return _internal_add_methods();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Method >&
 Api::methods() const {
@@ -814,8 +837,9 @@
   return options_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Option* Api::add_options() {
+  PROTOBUF_NAMESPACE_ID::Option* _add = _internal_add_options();
   // @@protoc_insertion_point(field_add:google.protobuf.Api.options)
-  return _internal_add_options();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Option >&
 Api::options() const {
@@ -839,8 +863,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Api.version)
 }
 inline std::string* Api::mutable_version() {
+  std::string* _s = _internal_mutable_version();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Api.version)
-  return _internal_mutable_version();
+  return _s;
 }
 inline const std::string& Api::_internal_version() const {
   return version_.Get();
@@ -922,8 +947,9 @@
   return source_context_;
 }
 inline PROTOBUF_NAMESPACE_ID::SourceContext* Api::mutable_source_context() {
+  PROTOBUF_NAMESPACE_ID::SourceContext* _msg = _internal_mutable_source_context();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Api.source_context)
-  return _internal_mutable_source_context();
+  return _msg;
 }
 inline void Api::set_allocated_source_context(PROTOBUF_NAMESPACE_ID::SourceContext* source_context) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -977,8 +1003,9 @@
   return mixins_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Mixin* Api::add_mixins() {
+  PROTOBUF_NAMESPACE_ID::Mixin* _add = _internal_add_mixins();
   // @@protoc_insertion_point(field_add:google.protobuf.Api.mixins)
-  return _internal_add_mixins();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Mixin >&
 Api::mixins() const {
@@ -1026,8 +1053,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Method.name)
 }
 inline std::string* Method::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Method.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Method::_internal_name() const {
   return name_.Get();
@@ -1071,8 +1099,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Method.request_type_url)
 }
 inline std::string* Method::mutable_request_type_url() {
+  std::string* _s = _internal_mutable_request_type_url();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Method.request_type_url)
-  return _internal_mutable_request_type_url();
+  return _s;
 }
 inline const std::string& Method::_internal_request_type_url() const {
   return request_type_url_.Get();
@@ -1136,8 +1165,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Method.response_type_url)
 }
 inline std::string* Method::mutable_response_type_url() {
+  std::string* _s = _internal_mutable_response_type_url();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Method.response_type_url)
-  return _internal_mutable_response_type_url();
+  return _s;
 }
 inline const std::string& Method::_internal_response_type_url() const {
   return response_type_url_.Get();
@@ -1212,8 +1242,9 @@
   return options_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Option* Method::add_options() {
+  PROTOBUF_NAMESPACE_ID::Option* _add = _internal_add_options();
   // @@protoc_insertion_point(field_add:google.protobuf.Method.options)
-  return _internal_add_options();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Option >&
 Method::options() const {
@@ -1261,8 +1292,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Mixin.name)
 }
 inline std::string* Mixin::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Mixin.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Mixin::_internal_name() const {
   return name_.Get();
@@ -1306,8 +1338,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Mixin.root)
 }
 inline std::string* Mixin::mutable_root() {
+  std::string* _s = _internal_mutable_root();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Mixin.root)
-  return _internal_mutable_root();
+  return _s;
 }
 inline const std::string& Mixin::_internal_root() const {
   return root_.Get();
diff --git a/src/google/protobuf/arena.h b/src/google/protobuf/arena.h
index e5d79d1..232cbd4 100644
--- a/src/google/protobuf/arena.h
+++ b/src/google/protobuf/arena.h
@@ -84,6 +84,10 @@
 
 }  // namespace arena_metrics
 
+namespace TestUtil {
+class ReflectionTester;  // defined in test_util.h
+}  // namespace TestUtil
+
 namespace internal {
 
 struct ArenaStringPtr;  // defined in arenastring.h
@@ -405,10 +409,43 @@
 
     // Provides access to protected GetArenaForAllocation to generated messages.
     static Arena* GetArenaForAllocation(const T* p) {
-      return p->GetArenaForAllocation();
+      return GetArenaForAllocationInternal(
+          p, std::is_convertible<T*, MessageLite*>());
     }
 
    private:
+    static Arena* GetArenaForAllocationInternal(
+        const T* p, std::true_type /*is_derived_from<MessageLite>*/) {
+      return p->GetArenaForAllocation();
+    }
+
+    static Arena* GetArenaForAllocationInternal(
+        const T* p, std::false_type /*is_derived_from<MessageLite>*/) {
+      return GetArenaForAllocationForNonMessage(
+          p, typename is_arena_constructable::type());
+    }
+
+    static Arena* GetArenaForAllocationForNonMessage(
+        const T* p, std::true_type /*is_arena_constructible*/) {
+      return p->GetArena();
+    }
+
+    static Arena* GetArenaForAllocationForNonMessage(
+        const T* p, std::false_type /*is_arena_constructible*/) {
+      return GetArenaForAllocationForNonMessageNonArenaConstructible(
+          p, typename has_get_arena::type());
+    }
+
+    static Arena* GetArenaForAllocationForNonMessageNonArenaConstructible(
+        const T* p, std::true_type /*has_get_arena*/) {
+      return p->GetArena();
+    }
+
+    static Arena* GetArenaForAllocationForNonMessageNonArenaConstructible(
+        const T* p, std::false_type /*has_get_arena*/) {
+      return nullptr;
+    }
+
     template <typename U>
     static char DestructorSkippable(const typename U::DestructorSkippable_*);
     template <typename U>
@@ -456,6 +493,7 @@
     static Arena* GetArena(const T* p) { return p->GetArena(); }
 
     friend class Arena;
+    friend class TestUtil::ReflectionTester;
   };
 
   // Helper typetraits that indicates support for arenas in a type T at compile
diff --git a/src/google/protobuf/arena_unittest.cc b/src/google/protobuf/arena_unittest.cc
index 7e90164..03c3d8d 100644
--- a/src/google/protobuf/arena_unittest.cc
+++ b/src/google/protobuf/arena_unittest.cc
@@ -622,7 +622,11 @@
     TestAllTypes::NestedMessage* arena2_submessage =
         Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
     arena2_submessage->set_bb(42);
-    arena1_message->set_allocated_optional_nested_message(arena2_submessage);
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+    EXPECT_DEBUG_DEATH(arena1_message->set_allocated_optional_nested_message(
+                           arena2_submessage),
+                       "submessage_arena");
+#endif
     EXPECT_NE(arena2_submessage,
               arena1_message->mutable_optional_nested_message());
   }
@@ -631,11 +635,43 @@
       Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena1);
   arena1_submessage->set_bb(42);
   TestAllTypes* heap_message = new TestAllTypes;
-  heap_message->set_allocated_optional_nested_message(arena1_submessage);
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+  EXPECT_DEBUG_DEATH(
+      heap_message->set_allocated_optional_nested_message(arena1_submessage),
+      "submessage_arena");
+#endif
   EXPECT_NE(arena1_submessage, heap_message->mutable_optional_nested_message());
   delete heap_message;
 }
 
+TEST(ArenaTest, UnsafeArenaSetAllocatedAcrossArenas) {
+  Arena arena1;
+  TestAllTypes* arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  {
+    Arena arena2;
+    TestAllTypes::NestedMessage* arena2_submessage =
+        Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
+    arena2_submessage->set_bb(42);
+    arena1_message->unsafe_arena_set_allocated_optional_nested_message(
+        arena2_submessage);
+    EXPECT_EQ(arena2_submessage,
+              arena1_message->mutable_optional_nested_message());
+    EXPECT_EQ(arena2_submessage,
+              arena1_message->unsafe_arena_release_optional_nested_message());
+  }
+
+  TestAllTypes::NestedMessage* arena1_submessage =
+      Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena1);
+  arena1_submessage->set_bb(42);
+  TestAllTypes* heap_message = new TestAllTypes;
+  heap_message->unsafe_arena_set_allocated_optional_nested_message(
+      arena1_submessage);
+  EXPECT_EQ(arena1_submessage, heap_message->mutable_optional_nested_message());
+  EXPECT_EQ(arena1_submessage,
+            heap_message->unsafe_arena_release_optional_nested_message());
+  delete heap_message;
+}
+
 TEST(ArenaTest, SetAllocatedAcrossArenasWithReflection) {
   // Same as above, with reflection.
   Arena arena1;
@@ -655,7 +691,11 @@
     TestAllTypes::NestedMessage* arena2_submessage =
         Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
     arena2_submessage->set_bb(42);
-    r->SetAllocatedMessage(arena1_message, arena2_submessage, msg_field);
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+    EXPECT_DEBUG_DEATH(
+        r->SetAllocatedMessage(arena1_message, arena2_submessage, msg_field),
+        "GetOwningArena");
+#endif
     EXPECT_NE(arena2_submessage,
               arena1_message->mutable_optional_nested_message());
   }
@@ -664,11 +704,47 @@
       Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena1);
   arena1_submessage->set_bb(42);
   TestAllTypes* heap_message = new TestAllTypes;
-  r->SetAllocatedMessage(heap_message, arena1_submessage, msg_field);
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+  EXPECT_DEBUG_DEATH(
+      r->SetAllocatedMessage(heap_message, arena1_submessage, msg_field),
+      "GetOwningArena");
+#endif
   EXPECT_NE(arena1_submessage, heap_message->mutable_optional_nested_message());
   delete heap_message;
 }
 
+TEST(ArenaTest, UnsafeArenaSetAllocatedAcrossArenasWithReflection) {
+  // Same as above, with reflection.
+  Arena arena1;
+  TestAllTypes* arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  const Reflection* r = arena1_message->GetReflection();
+  const Descriptor* d = arena1_message->GetDescriptor();
+  const FieldDescriptor* msg_field =
+      d->FindFieldByName("optional_nested_message");
+  {
+    Arena arena2;
+    TestAllTypes::NestedMessage* arena2_submessage =
+        Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
+    arena2_submessage->set_bb(42);
+    r->UnsafeArenaSetAllocatedMessage(arena1_message, arena2_submessage,
+                                      msg_field);
+    EXPECT_EQ(arena2_submessage,
+              arena1_message->mutable_optional_nested_message());
+    EXPECT_EQ(arena2_submessage,
+              arena1_message->unsafe_arena_release_optional_nested_message());
+  }
+
+  TestAllTypes::NestedMessage* arena1_submessage =
+      Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena1);
+  arena1_submessage->set_bb(42);
+  TestAllTypes* heap_message = new TestAllTypes;
+  r->UnsafeArenaSetAllocatedMessage(heap_message, arena1_submessage, msg_field);
+  EXPECT_EQ(arena1_submessage, heap_message->mutable_optional_nested_message());
+  EXPECT_EQ(arena1_submessage,
+            heap_message->unsafe_arena_release_optional_nested_message());
+  delete heap_message;
+}
+
 TEST(ArenaTest, AddAllocatedWithReflection) {
   Arena arena1;
   ArenaMessage* arena1_message = Arena::CreateMessage<ArenaMessage>(&arena1);
@@ -727,29 +803,35 @@
     TestAllTypes::NestedMessage* arena2_submessage =
         Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
     arena2_submessage->set_bb(42);
-    arena1_message->mutable_repeated_nested_message()->AddAllocated(
-        arena2_submessage);
-    // Should copy object.
-    EXPECT_NE(arena2_submessage, &arena1_message->repeated_nested_message(i));
-    EXPECT_EQ(42, arena1_message->repeated_nested_message(i).bb());
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+    EXPECT_DEBUG_DEATH(
+        arena1_message->mutable_repeated_nested_message()->AddAllocated(
+            arena2_submessage),
+        "value_arena");
+#endif
+    // Should not receive object.
+    EXPECT_TRUE(arena1_message->repeated_nested_message().empty());
   }
 
   // Arena->heap case.
-  TestAllTypes* heap_message = new TestAllTypes();
+  TestAllTypes* heap_message = new TestAllTypes;
   for (int i = 0; i < 10; i++) {
     Arena arena2;
     TestAllTypes::NestedMessage* arena2_submessage =
         Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
     arena2_submessage->set_bb(42);
-    heap_message->mutable_repeated_nested_message()->AddAllocated(
-        arena2_submessage);
-    // Should copy object.
-    EXPECT_NE(arena2_submessage, &heap_message->repeated_nested_message(i));
-    EXPECT_EQ(42, heap_message->repeated_nested_message(i).bb());
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+    EXPECT_DEBUG_DEATH(
+        heap_message->mutable_repeated_nested_message()->AddAllocated(
+            arena2_submessage),
+        "value_arena");
+#endif
+    // Should not receive object.
+    EXPECT_TRUE(heap_message->repeated_nested_message().empty());
   }
   delete heap_message;
 
-  // Heap-arena case for strings (which are not arena-allocated).
+  // Heap->arena case for strings (which are not arena-allocated).
   arena1_message->Clear();
   for (int i = 0; i < 10; i++) {
     std::string* s = new std::string("Test");
@@ -760,6 +842,65 @@
   }
 }
 
+TEST(ArenaTest, UnsafeArenaAddAllocatedToRepeatedField) {
+  // Heap->arena case.
+  Arena arena1;
+  TestAllTypes* arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  {
+    auto* heap_submessage = new TestAllTypes::NestedMessage;
+    arena1_message->mutable_repeated_nested_message()->UnsafeArenaAddAllocated(
+        heap_submessage);
+    // Should not copy object.
+    EXPECT_EQ(heap_submessage, &arena1_message->repeated_nested_message(0));
+    EXPECT_EQ(heap_submessage, arena1_message->mutable_repeated_nested_message()
+                                   ->UnsafeArenaReleaseLast());
+    delete heap_submessage;
+  }
+
+  // Arena1->Arena2 case.
+  arena1_message->Clear();
+  {
+    Arena arena2;
+    TestAllTypes::NestedMessage* arena2_submessage =
+        Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
+    arena2_submessage->set_bb(42);
+    arena1_message->mutable_repeated_nested_message()->UnsafeArenaAddAllocated(
+        arena2_submessage);
+    // Should own object.
+    EXPECT_EQ(arena2_submessage, &arena1_message->repeated_nested_message(0));
+    EXPECT_EQ(arena2_submessage,
+              arena1_message->mutable_repeated_nested_message()
+                  ->UnsafeArenaReleaseLast());
+  }
+
+  // Arena->heap case.
+  TestAllTypes* heap_message = new TestAllTypes;
+  {
+    Arena arena2;
+    TestAllTypes::NestedMessage* arena2_submessage =
+        Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
+    arena2_submessage->set_bb(42);
+    heap_message->mutable_repeated_nested_message()->UnsafeArenaAddAllocated(
+        arena2_submessage);
+    // Should own object.
+    EXPECT_EQ(arena2_submessage, &heap_message->repeated_nested_message(0));
+    EXPECT_EQ(arena2_submessage, heap_message->mutable_repeated_nested_message()
+                                     ->UnsafeArenaReleaseLast());
+  }
+  delete heap_message;
+
+  // Heap->arena case for strings (which are not arena-allocated).
+  arena1_message->Clear();
+  {
+    std::string* s = new std::string("Test");
+    arena1_message->mutable_repeated_string()->UnsafeArenaAddAllocated(s);
+    // Should not copy.
+    EXPECT_EQ(s, &arena1_message->repeated_string(0));
+    EXPECT_EQ("Test", arena1_message->repeated_string(0));
+    delete arena1_message->mutable_repeated_string()->UnsafeArenaReleaseLast();
+  }
+}
+
 TEST(ArenaTest, AddAllocatedToRepeatedFieldViaReflection) {
   // Heap->arena case.
   Arena arena1;
@@ -784,10 +925,13 @@
     TestAllTypes::NestedMessage* arena2_submessage =
         Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
     arena2_submessage->set_bb(42);
-    r->AddAllocatedMessage(arena1_message, fd, arena2_submessage);
-    // Should copy object.
-    EXPECT_NE(arena2_submessage, &arena1_message->repeated_nested_message(i));
-    EXPECT_EQ(42, arena1_message->repeated_nested_message(i).bb());
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+    EXPECT_DEBUG_DEATH(
+        r->AddAllocatedMessage(arena1_message, fd, arena2_submessage),
+        "value_arena");
+#endif
+    // Should not receive object.
+    EXPECT_TRUE(arena1_message->repeated_nested_message().empty());
   }
 
   // Arena->heap case.
@@ -797,10 +941,13 @@
     TestAllTypes::NestedMessage* arena2_submessage =
         Arena::CreateMessage<TestAllTypes::NestedMessage>(&arena2);
     arena2_submessage->set_bb(42);
-    r->AddAllocatedMessage(heap_message, fd, arena2_submessage);
-    // Should copy object.
-    EXPECT_NE(arena2_submessage, &heap_message->repeated_nested_message(i));
-    EXPECT_EQ(42, heap_message->repeated_nested_message(i).bb());
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+    EXPECT_DEBUG_DEATH(
+        r->AddAllocatedMessage(heap_message, fd, arena2_submessage),
+        "value_arena");
+#endif
+    // Should not receive object.
+    EXPECT_TRUE(heap_message->repeated_nested_message().empty());
   }
   delete heap_message;
 }
diff --git a/src/google/protobuf/arenastring.h b/src/google/protobuf/arenastring.h
index 75c1667..1fafa69 100644
--- a/src/google/protobuf/arenastring.h
+++ b/src/google/protobuf/arenastring.h
@@ -54,6 +54,8 @@
 template <typename T>
 class ExplicitlyConstructed;
 
+class SwapFieldHelper;
+
 // Lazy string instance to support string fields with non-empty default.
 // These are initialized on the first call to .get().
 class PROTOBUF_EXPORT LazyString {
@@ -241,9 +243,9 @@
   // Own()'d by any arena. If the field is not set, this returns NULL. The
   // caller retains ownership. Clears this field back to NULL state. Used to
   // implement release_<field>() methods on generated classes.
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* Release(
+  PROTOBUF_MUST_USE_RESULT std::string* Release(
       const std::string* default_value, ::google::protobuf::Arena* arena);
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* ReleaseNonDefault(
+  PROTOBUF_MUST_USE_RESULT std::string* ReleaseNonDefault(
       const std::string* default_value, ::google::protobuf::Arena* arena);
 
   // Takes a std::string that is heap-allocated, and takes ownership. The
@@ -322,6 +324,15 @@
 
   bool IsDonatedString() const { return false; }
 
+  // Swaps tagged pointer without debug hardening. This is to allow python
+  // protobuf to maintain pointer stability even in DEBUG builds.
+  inline PROTOBUF_NDEBUG_INLINE static void UnsafeShallowSwap(
+      ArenaStringPtr* rhs, ArenaStringPtr* lhs) {
+    std::swap(lhs->tagged_ptr_, rhs->tagged_ptr_);
+  }
+
+  friend class ::google::protobuf::internal::SwapFieldHelper;
+
   // Slow paths.
 
   // MutableSlow requires that !IsString() || IsDefault
@@ -348,8 +359,7 @@
   (void)default_value;
   std::swap(lhs_arena, rhs_arena);
   std::swap(lhs->tagged_ptr_, rhs->tagged_ptr_);
-#if 0  // TODO(b/186650244): renable this
-#ifndef NDEBUG
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
   auto force_realloc = [default_value](ArenaStringPtr* p, Arena* arena) {
     if (p->IsDefault(default_value)) return;
     std::string* old_value = p->tagged_ptr_.Get();
@@ -362,8 +372,7 @@
   };
   force_realloc(lhs, lhs_arena);
   force_realloc(rhs, rhs_arena);
-#endif
-#endif
+#endif  // PROTOBUF_FORCE_COPY_IN_SWAP
 }
 
 inline void ArenaStringPtr::ClearNonDefaultToEmpty() {
diff --git a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
index 31fe5a6..60619f1 100644
--- a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
@@ -137,14 +137,10 @@
   // of the data to compare to.
   std::map<std::string, std::string> vpath_map;
   std::map<std::string, std::string> rpath_map;
-  rpath_map
-      ["third_party/protobuf_legacy_opensource/src/google/protobuf/"
-       "test_messages_proto2"] =
-          "net/proto2/z_generated_example/test_messages_proto2";
-  rpath_map
-      ["third_party/protobuf_legacy_opensource/src/google/protobuf/"
-       "test_messages_proto3"] =
-          "net/proto2/z_generated_example/test_messages_proto3";
+  rpath_map["third_party/protobuf/src/google/protobuf/test_messages_proto2"] =
+      "net/proto2/z_generated_example/test_messages_proto2";
+  rpath_map["third_party/protobuf/src/google/protobuf/test_messages_proto3"] =
+      "net/proto2/z_generated_example/test_messages_proto3";
   rpath_map["net/proto2/internal/proto2_weak"] =
       "net/proto2/z_generated_example/proto2_weak";
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
index 57e6d7e..6b9a5eb 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
@@ -93,7 +93,7 @@
       "  return static_cast< $type$ >($name$_);\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
@@ -106,8 +106,8 @@
       "  $name$_ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
-      "$annotate_accessor$"
       "  _internal_set_$name$(value);\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n");
 }
@@ -183,7 +183,7 @@
       "  return static_cast< $type$ >($default$);\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
@@ -199,9 +199,9 @@
       "  $field_member$ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
-      "$annotate_accessor$"
-      "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "  _internal_set_$name$(value);\n"
+      "$annotate_set$"
+      "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n");
 }
 
@@ -268,17 +268,17 @@
       "  return static_cast< $type$ >($name$_.Get(index));\n"
       "}\n"
       "inline $type$ $classname$::$name$(int index) const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$(index);\n"
       "}\n"
-      "inline void $classname$::set_$name$(int index, $type$ value) {\n"
-      "$annotate_accessor$");
+      "inline void $classname$::set_$name$(int index, $type$ value) {\n");
   if (!HasPreservingUnknownEnumSemantics(descriptor_)) {
     format("  assert($type$_IsValid(value));\n");
   }
   format(
       "  $name$_.Set(index, value);\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline void $classname$::_internal_add_$name$($type$ value) {\n");
@@ -289,13 +289,13 @@
       "  $name$_.Add(value);\n"
       "}\n"
       "inline void $classname$::add_$name$($type$ value) {\n"
-      "$annotate_accessor$"
-      "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "  _internal_add_$name$(value);\n"
+      "$annotate_add$"
+      "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "}\n"
       "inline const ::$proto_ns$::RepeatedField<int>&\n"
       "$classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
       "  return $name$_;\n"
       "}\n"
@@ -305,7 +305,7 @@
       "}\n"
       "inline ::$proto_ns$::RepeatedField<int>*\n"
       "$classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable_list$"
       "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
       "  return _internal_mutable_$name$();\n"
       "}\n");
diff --git a/src/google/protobuf/compiler/cpp/cpp_field.cc b/src/google/protobuf/compiler/cpp/cpp_field.cc
index b28f6f2..949405d 100644
--- a/src/google/protobuf/compiler/cpp/cpp_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_field.cc
@@ -36,10 +36,13 @@
 
 #include <cstdint>
 #include <memory>
+#include <string>
 
 #include <google/protobuf/compiler/cpp/cpp_helpers.h>
 #include <google/protobuf/compiler/cpp/cpp_primitive_field.h>
 #include <google/protobuf/compiler/cpp/cpp_string_field.h>
+#include <google/protobuf/stubs/strutil.h>
+#include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/compiler/cpp/cpp_enum_field.h>
@@ -48,7 +51,6 @@
 #include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/wire_format.h>
-#include <google/protobuf/stubs/strutil.h>
 
 namespace google {
 namespace protobuf {
@@ -57,6 +59,23 @@
 
 using internal::WireFormat;
 
+
+void AddAccessorAnnotations(const FieldDescriptor* descriptor,
+                            const Options& options,
+                            std::map<std::string, std::string>* variables) {
+  // Can be expanded to include more specific calls, for example, for arena or
+  // clear calls.
+  static constexpr const char* kAccessorsAnnotations[] = {
+      "annotate_add",     "annotate_get",         "annotate_has",
+      "annotate_list",    "annotate_mutable",     "annotate_mutable_list",
+      "annotate_release", "annotate_set",         "annotate_size",
+      "annotate_clear",   "annotate_add_mutable",
+  };
+  for (size_t i = 0; i < GOOGLE_ARRAYSIZE(kAccessorsAnnotations); ++i) {
+    (*variables)[kAccessorsAnnotations[i]] = "";
+  }
+}
+
 void SetCommonFieldVariables(const FieldDescriptor* descriptor,
                              std::map<std::string, std::string>* variables,
                              const Options& options) {
@@ -81,7 +100,8 @@
   } else {
     (*variables)["set_hasbit_io"] = "";
   }
-  (*variables)["annotate_accessor"] = "";
+
+  AddAccessorAnnotations(descriptor, options, variables);
 
   // These variables are placeholders to pick out the beginning and ends of
   // identifiers for annotations (when doing so with existing variables would
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.cc b/src/google/protobuf/compiler/cpp/cpp_file.cc
index 9a0c7ab..6dff1d0 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_file.cc
@@ -403,6 +403,11 @@
     IncludeFile("net/proto2/public/wire_format.h", printer);
   }
 
+  if (HasGeneratedMethods(file_, options_) &&
+      options_.tctable_mode != Options::kTCTableNever) {
+    IncludeFile("net/proto2/public/generated_message_tctable_impl.h", printer);
+  }
+
   if (options_.proto_h) {
     // Use the smaller .proto.h files.
     for (int i = 0; i < file_->dependency_count(); i++) {
@@ -1166,6 +1171,10 @@
   IncludeFile("net/proto2/public/arena.h", printer);
   IncludeFile("net/proto2/public/arenastring.h", printer);
   IncludeFile("net/proto2/public/generated_message_table_driven.h", printer);
+  if (HasGeneratedMethods(file_, options_) &&
+      options_.tctable_mode != Options::kTCTableNever) {
+    IncludeFile("net/proto2/public/generated_message_tctable_decl.h", printer);
+  }
   IncludeFile("net/proto2/public/generated_message_util.h", printer);
   IncludeFile("net/proto2/public/metadata_lite.h", printer);
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.cc b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
index 66f6359..16ee074 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
@@ -245,9 +245,9 @@
   (*variables)["string"] = "std::string";
 }
 
-void SetUnknkownFieldsVariable(const Descriptor* descriptor,
-                               const Options& options,
-                               std::map<std::string, std::string>* variables) {
+void SetUnknownFieldsVariable(const Descriptor* descriptor,
+                              const Options& options,
+                              std::map<std::string, std::string>* variables) {
   std::string proto_ns = ProtobufNamespace(options);
   std::string unknown_fields_type;
   if (UseUnknownFieldSet(descriptor->file(), options)) {
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.h b/src/google/protobuf/compiler/cpp/cpp_helpers.h
index e9c7b64..d15ac29 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.h
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.h
@@ -85,9 +85,9 @@
 void SetCommonVars(const Options& options,
                    std::map<std::string, std::string>* variables);
 
-void SetUnknkownFieldsVariable(const Descriptor* descriptor,
-                               const Options& options,
-                               std::map<std::string, std::string>* variables);
+void SetUnknownFieldsVariable(const Descriptor* descriptor,
+                              const Options& options,
+                              std::map<std::string, std::string>* variables);
 
 bool GetBootstrapBasename(const Options& options, const std::string& basename,
                           std::string* bootstrap_basename);
@@ -342,7 +342,8 @@
          !options.opensource_runtime;
 }
 
-inline bool IsFieldUsed(const FieldDescriptor* /* field */, const Options& /* options */) {
+inline bool IsFieldUsed(const FieldDescriptor* /* field */,
+                        const Options& options) {
   return true;
 }
 
@@ -710,7 +711,7 @@
     std::vector<int> path;
     descriptor->GetLocationPath(&path);
     GeneratedCodeInfo::Annotation annotation;
-    for (int index: path) {
+    for (int index : path) {
       annotation.add_path(index);
     }
     annotation.set_source_file(descriptor->file()->name());
@@ -749,7 +750,8 @@
       if (name_stack_[common_idx] != new_stack_[common_idx]) break;
       common_idx++;
     }
-    for (auto it = name_stack_.crbegin(); it != name_stack_.crend() - common_idx; ++it) {
+    for (auto it = name_stack_.crbegin();
+         it != name_stack_.crend() - common_idx; ++it) {
       if (*it == "PROTOBUF_NAMESPACE_ID") {
         printer_->Print("PROTOBUF_NAMESPACE_CLOSE\n");
       } else {
@@ -864,6 +866,8 @@
 
 PROTOC_EXPORT std::string StripProto(const std::string& filename);
 
+inline bool EnableMessageOwnedArena(const Descriptor* desc) { return false; }
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.cc b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
index 4d735c3..49f65f3 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
@@ -129,7 +129,7 @@
       "}\n"
       "inline const ::$proto_ns$::Map< $key_cpp$, $val_cpp$ >&\n"
       "$classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_map:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
@@ -139,7 +139,7 @@
       "}\n"
       "inline ::$proto_ns$::Map< $key_cpp$, $val_cpp$ >*\n"
       "$classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable_map:$full_name$)\n"
       "  return _internal_mutable_$name$();\n"
       "}\n");
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.h b/src/google/protobuf/compiler/cpp/cpp_map_field.h
index 33dec91..5ea0429 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.h
@@ -47,17 +47,18 @@
   ~MapFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
-  void GeneratePrivateMembers(io::Printer* printer) const;
-  void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
-  void GenerateClearingCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateSwappingCode(io::Printer* printer) const;
-  void GenerateConstructorCode(io::Printer* printer) const {}
-  void GenerateCopyConstructorCode(io::Printer* printer) const;
-  void GenerateSerializeWithCachedSizesToArray(io::Printer* printer) const;
-  void GenerateByteSize(io::Printer* printer) const;
-  void GenerateConstinitInitializer(io::Printer* printer) const;
+  void GeneratePrivateMembers(io::Printer* printer) const override;
+  void GenerateAccessorDeclarations(io::Printer* printer) const override;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer) const override;
+  void GenerateClearingCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateSwappingCode(io::Printer* printer) const override;
+  void GenerateConstructorCode(io::Printer* printer) const override {}
+  void GenerateCopyConstructorCode(io::Printer* printer) const override;
+  void GenerateSerializeWithCachedSizesToArray(
+      io::Printer* printer) const override;
+  void GenerateByteSize(io::Printer* printer) const override;
+  void GenerateConstinitInitializer(io::Printer* printer) const override;
   bool GenerateArenaDestructorCode(io::Printer* printer) const override;
 
  private:
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index 8e91103..68840d5 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -61,6 +61,9 @@
 #include <google/protobuf/stubs/hash.h>
 
 
+// Must be included last.
+#include <google/protobuf/port_def.inc>
+
 namespace google {
 namespace protobuf {
 namespace compiler {
@@ -571,7 +574,12 @@
   variables_["classtype"] = QualifiedClassName(descriptor_, options);
   variables_["full_name"] = descriptor_->full_name();
   variables_["superclass"] = SuperClassName(descriptor_, options_);
-  SetUnknkownFieldsVariable(descriptor_, options_, &variables_);
+  variables_["annotate_serialize"] = "";
+  variables_["annotate_deserialize"] = "";
+  variables_["annotate_reflection"] = "";
+  variables_["annotate_bytesize"] = "";
+
+  SetUnknownFieldsVariable(descriptor_, options_, &variables_);
 
   // Compute optimized field order to be used for layout and initialization
   // purposes.
@@ -612,7 +620,8 @@
 
   table_driven_ = TableDrivenParsingEnabled(descriptor_, options_);
   parse_function_generator_.reset(new ParseFunctionGenerator(
-      descriptor_, max_has_bit_index_, options_, scc_analyzer_));
+      descriptor_, max_has_bit_index_, has_bit_indices_, options_,
+      scc_analyzer_, variables_));
 }
 
 MessageGenerator::~MessageGenerator() = default;
@@ -767,7 +776,7 @@
   if (field->options().weak()) {
     format(
         "inline bool $classname$::has_$name$() const {\n"
-        "$annotate_accessor$"
+        "$annotate_has$"
         "  return _weak_field_map_.Has($number$);\n"
         "}\n");
     return;
@@ -796,7 +805,7 @@
         "  return value;\n"
         "}\n"
         "inline bool $classname$::has_$name$() const {\n"
-        "$annotate_accessor$"
+        "$annotate_has$"
         "  return _internal_has_$name$();\n"
         "}\n");
   } else if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
@@ -815,7 +824,7 @@
     }
     format(
         "inline bool $classname$::has_$name$() const {\n"
-        "$annotate_accessor$"
+        "$annotate_has$"
         "  return _internal_has_$name$();\n"
         "}\n");
   }
@@ -865,7 +874,7 @@
         "  return $oneof_name$_case() == k$field_name$;\n"
         "}\n"
         "inline bool $classname$::has_$name$() const {\n"
-        "$annotate_accessor$"
+        "$annotate_has$"
         "  return _internal_has_$name$();\n"
         "}\n");
   } else if (HasPrivateHasMethod(field)) {
@@ -893,9 +902,7 @@
   if (is_inline) {
     format("inline ");
   }
-  format(
-      "void $classname$::clear_$name$() {\n"
-      "$annotate_accessor$");
+  format("void $classname$::clear_$name$() {\n");
 
   format.Indent();
 
@@ -918,7 +925,7 @@
       format("_has_bits_[$has_array_index$] &= ~0x$has_mask$u;\n");
     }
   }
-
+  format("$annotate_clear$");
   format.Outdent();
   format("}\n");
 }
@@ -952,7 +959,7 @@
             "  return $name$_$1$.size();\n"
             "}\n"
             "inline int $classname$::$name$_size() const {\n"
-            "$annotate_accessor$"
+            "$annotate_size$"
             "  return _internal_$name$_size();\n"
             "}\n",
             IsImplicitWeakField(field, options_, scc_analyzer_) &&
@@ -1079,7 +1086,8 @@
     }
     if (HasDescriptorMethods(descriptor_->file(), options_)) {
       format(
-          "  void MergeFrom(const ::$proto_ns$::Message& other) final;\n"
+          "  using ::$proto_ns$::Message::MergeFrom;\n"
+          ""
           "  ::$proto_ns$::Metadata GetMetadata() const final;\n");
     }
     format("};\n");
@@ -1094,8 +1102,14 @@
   format(" public:\n");
   format.Indent();
 
+  if (EnableMessageOwnedArena(descriptor_)) {
+    format(
+        "inline $classname$() : $classname$("
+        "new ::$proto_ns$::Arena(), true) {}\n");
+  } else {
+    format("inline $classname$() : $classname$(nullptr) {}\n");
+  }
   format(
-      "inline $classname$() : $classname$(nullptr) {}\n"
       "~$classname$() override;\n"
       "explicit constexpr "
       "$classname$(::$proto_ns$::internal::ConstantInitialized);\n"
@@ -1163,6 +1177,7 @@
         "  return default_instance().GetMetadata().descriptor;\n"
         "}\n"
         "static const ::$proto_ns$::Reflection* GetReflection() {\n"
+        "$annotate_reflection$"
         "  return default_instance().GetMetadata().reflection;\n"
         "}\n");
   }
@@ -1274,7 +1289,12 @@
       "}\n"
       "inline void Swap($classname$* other) {\n"
       "  if (other == this) return;\n"
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+      "  if (GetOwningArena() != nullptr &&\n"
+      "      GetOwningArena() == other->GetOwningArena()) {\n"
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
       "  if (GetOwningArena() == other->GetOwningArena()) {\n"
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
       "    InternalSwap(other);\n"
       "  } else {\n"
       "    ::PROTOBUF_NAMESPACE_ID::internal::GenericSwap(this, other);\n"
@@ -1307,20 +1327,33 @@
   if (HasGeneratedMethods(descriptor_->file(), options_)) {
     if (HasDescriptorMethods(descriptor_->file(), options_)) {
       format(
-          "void CopyFrom(const ::$proto_ns$::Message& from) final;\n"
-          "void MergeFrom(const ::$proto_ns$::Message& from) final;\n");
+          // Use Message's built-in MergeFrom and CopyFrom when the passed-in
+          // argument is a generic Message instance, and only define the custom
+          // MergeFrom and CopyFrom instances when the source of the merge/copy
+          // is known to be the same class as the destination.
+          // TODO(jorg): Define MergeFrom in terms of MergeImpl, rather than the
+          // other way around, to save even more code size.
+          "using $superclass$::CopyFrom;\n"
+          "void CopyFrom(const $classname$& from);\n"
+          ""
+          "using $superclass$::MergeFrom;\n"
+          "void MergeFrom(const $classname$& from);\n"
+          "private:\n"
+          "static void MergeImpl(::$proto_ns$::Message*to, const "
+          "::$proto_ns$::Message&from);\n"
+          "public:\n");
     } else {
       format(
-          "void CheckTypeAndMergeFrom(const ::$proto_ns$::MessageLite& from)\n"
-          "  final;\n");
+          "void CheckTypeAndMergeFrom(const ::$proto_ns$::MessageLite& from)"
+          "  final;\n"
+          "void CopyFrom(const $classname$& from);\n"
+          "void MergeFrom(const $classname$& from);\n");
     }
 
     format.Set("clear_final",
                ShouldMarkClearAsFinal(descriptor_, options_) ? "final" : "");
 
     format(
-        "void CopyFrom(const $classname$& from);\n"
-        "void MergeFrom(const $classname$& from);\n"
         "PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear()$ clear_final$;\n"
         "bool IsInitialized() const final;\n"
         "\n"
@@ -1362,7 +1395,8 @@
       // protos to give access to this constructor, breaking the invariants
       // we rely on.
       "protected:\n"
-      "explicit $classname$(::$proto_ns$::Arena* arena);\n"
+      "explicit $classname$(::$proto_ns$::Arena* arena,\n"
+      "                     bool is_message_owned = false);\n"
       "private:\n"
       "static void ArenaDtor(void* object);\n"
       "inline void RegisterArenaDtor(::$proto_ns$::Arena* arena);\n");
@@ -1372,6 +1406,13 @@
       "\n");
 
   if (HasDescriptorMethods(descriptor_->file(), options_)) {
+    if (HasGeneratedMethods(descriptor_->file(), options_)) {
+      format(
+          "static const ClassData _class_data_;\n"
+          "const ::$proto_ns$::Message::ClassData*"
+          "GetClassData() const final;\n"
+          "\n");
+    }
     format(
         "::$proto_ns$::Metadata GetMetadata() const final;\n"
         "\n");
@@ -1454,6 +1495,10 @@
         "size_t RequiredFieldsByteSizeFallback() const;\n\n");
   }
 
+  if (HasGeneratedMethods(descriptor_->file(), options_)) {
+    parse_function_generator_->GenerateDataDecls(printer);
+  }
+
   // Prepare decls for _cached_size_ and _has_bits_.  Their position in the
   // output will be determined later.
 
@@ -1882,12 +1927,6 @@
           "      $file_level_metadata$[$1$]);\n"
           "}\n",
           index_in_file_messages_);
-      format(
-          "void $classname$::MergeFrom(\n"
-          "    const ::$proto_ns$::Message& other) {\n"
-          "  ::$proto_ns$::Message::MergeFrom(other);\n"
-          "}\n"
-          "\n");
     }
     return;
   }
@@ -1987,6 +2026,8 @@
     parse_function_generator_->GenerateMethodImpls(printer);
     format("\n");
 
+    parse_function_generator_->GenerateDataDefinitions(printer);
+
     GenerateSerializeWithCachedSizesToArray(printer);
     format("\n");
 
@@ -2302,7 +2343,7 @@
 void MessageGenerator::GenerateSharedConstructorCode(io::Printer* printer) {
   Formatter format(printer, variables_);
 
-  format("void $classname$::SharedCtor() {\n");
+  format("inline void $classname$::SharedCtor() {\n");
 
   std::vector<bool> processed(optimized_order_.size(), false);
   GenerateConstructorBody(printer, processed, false);
@@ -2317,7 +2358,7 @@
 void MessageGenerator::GenerateSharedDestructorCode(io::Printer* printer) {
   Formatter format(printer, variables_);
 
-  format("void $classname$::SharedDtor() {\n");
+  format("inline void $classname$::SharedDtor() {\n");
   format.Indent();
   format("$DCHK$(GetArenaForAllocation() == nullptr);\n");
   // Write the destructors for each field except oneof members.
@@ -2502,7 +2543,7 @@
 
   std::string superclass;
   superclass = SuperClassName(descriptor_, options_);
-  std::string initializer_with_arena = superclass + "(arena)";
+  std::string initializer_with_arena = superclass + "(arena, is_message_owned)";
 
   if (descriptor_->extension_range_count() > 0) {
     initializer_with_arena += ",\n  _extensions_(arena)";
@@ -2538,16 +2579,19 @@
   }
 
   format(
-      "$classname$::$classname$(::$proto_ns$::Arena* arena)\n"
+      "$classname$::$classname$(::$proto_ns$::Arena* arena,\n"
+      "                         bool is_message_owned)\n"
       "  : $1$ {\n"
       "  SharedCtor();\n"
-      "  RegisterArenaDtor(arena);\n"
+      "  if (!is_message_owned) {\n"
+      "    RegisterArenaDtor(arena);\n"
+      "  }\n"
       "  // @@protoc_insertion_point(arena_constructor:$full_name$)\n"
       "}\n",
       initializer_with_arena);
 
   std::map<std::string, std::string> vars;
-  SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+  SetUnknownFieldsVariable(descriptor_, options_, &vars);
   format.AddMap(vars);
 
   // Generate the copy constructor.
@@ -2646,6 +2690,7 @@
   format(
       "$classname$::~$classname$() {\n"
       "  // @@protoc_insertion_point(destructor:$full_name$)\n"
+      "  if (GetArenaForAllocation() != nullptr) return;\n"
       "  SharedDtor();\n"
       "  _internal_metadata_.Delete<$unknown_fields_type$>();\n"
       "}\n"
@@ -2838,7 +2883,7 @@
   }
 
   std::map<std::string, std::string> vars;
-  SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+  SetUnknownFieldsVariable(descriptor_, options_, &vars);
   format.AddMap(vars);
   format("_internal_metadata_.Clear<$unknown_fields_type$>();\n");
 
@@ -2903,7 +2948,7 @@
     }
 
     std::map<std::string, std::string> vars;
-    SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+    SetUnknownFieldsVariable(descriptor_, options_, &vars);
     format.AddMap(vars);
     format("_internal_metadata_.InternalSwap(&other->_internal_metadata_);\n");
 
@@ -2973,35 +3018,30 @@
 void MessageGenerator::GenerateMergeFrom(io::Printer* printer) {
   Formatter format(printer, variables_);
   if (HasDescriptorMethods(descriptor_->file(), options_)) {
-    // Generate the generalized MergeFrom (aka that which takes in the Message
-    // base class as a parameter).
-    format(
-        "void $classname$::MergeFrom(const ::$proto_ns$::Message& from) {\n"
-        "// @@protoc_insertion_point(generalized_merge_from_start:"
-        "$full_name$)\n"
-        "  $DCHK$_NE(&from, this);\n");
-    format.Indent();
+    // We don't override the generalized MergeFrom (aka that which
+    // takes in the Message base class as a parameter); instead we just
+    // let the base Message::MergeFrom take care of it.  The base MergeFrom
+    // knows how to quickly confirm the types exactly match, and if so, will
+    // use GetClassData() to retrieve the address of MergeImpl, which calls
+    // the fast MergeFrom overload.  Most callers avoid all this by passing
+    // a "from" message that is the same type as the message being merged
+    // into, rather than a generic Message.
 
-    // Cast the message to the proper type. If we find that the message is
-    // *not* of the proper type, we can still call Merge via the reflection
-    // system, as the GOOGLE_CHECK above ensured that we have the same descriptor
-    // for each message.
     format(
-        "const $classname$* source =\n"
-        "    ::$proto_ns$::DynamicCastToGenerated<$classname$>(\n"
-        "        &from);\n"
-        "if (source == nullptr) {\n"
-        "// @@protoc_insertion_point(generalized_merge_from_cast_fail:"
-        "$full_name$)\n"
-        "  ::$proto_ns$::internal::ReflectionOps::Merge(from, this);\n"
-        "} else {\n"
-        "// @@protoc_insertion_point(generalized_merge_from_cast_success:"
-        "$full_name$)\n"
-        "  MergeFrom(*source);\n"
-        "}\n");
-
-    format.Outdent();
-    format("}\n");
+        "const ::$proto_ns$::Message::ClassData "
+        "$classname$::_class_data_ = {\n"
+        "    ::$proto_ns$::Message::CopyWithSizeCheck,\n"
+        "    $classname$::MergeImpl\n"
+        "};\n"
+        "const ::$proto_ns$::Message::ClassData*"
+        "$classname$::GetClassData() const { return &_class_data_; }\n"
+        "\n"
+        "void $classname$::MergeImpl(::$proto_ns$::Message*to,\n"
+        "                      const ::$proto_ns$::Message&from) {\n"
+        "  static_cast<$classname$ *>(to)->MergeFrom(\n"
+        "      static_cast<const $classname$ &>(from));\n"
+        "}\n"
+        "\n");
   } else {
     // Generate CheckTypeAndMergeFrom().
     format(
@@ -3023,15 +3063,7 @@
       "  $DCHK$_NE(&from, this);\n");
   format.Indent();
 
-  if (descriptor_->extension_range_count() > 0) {
-    format("_extensions_.MergeFrom(from._extensions_);\n");
-  }
-  std::map<std::string, std::string> vars;
-  SetUnknkownFieldsVariable(descriptor_, options_, &vars);
-  format.AddMap(vars);
   format(
-      "_internal_metadata_.MergeFrom<$unknown_fields_type$>(from._internal_"
-      "metadata_);\n"
       "$uint32$ cached_has_bits = 0;\n"
       "(void) cached_has_bits;\n\n");
 
@@ -3169,6 +3201,16 @@
     format("_weak_field_map_.MergeFrom(from._weak_field_map_);\n");
   }
 
+  // Merging of extensions and unknown fields is done last, to maximize
+  // the opportunity for tail calls.
+  if (descriptor_->extension_range_count() > 0) {
+    format("_extensions_.MergeFrom(from._extensions_);\n");
+  }
+
+  format(
+      "_internal_metadata_.MergeFrom<$unknown_fields_type$>(from._internal_"
+      "metadata_);\n");
+
   format.Outdent();
   format("}\n");
 }
@@ -3176,38 +3218,16 @@
 void MessageGenerator::GenerateCopyFrom(io::Printer* printer) {
   Formatter format(printer, variables_);
   if (HasDescriptorMethods(descriptor_->file(), options_)) {
-    // Generate the generalized CopyFrom (aka that which takes in the Message
-    // base class as a parameter).
-    format(
-        "void $classname$::CopyFrom(const ::$proto_ns$::Message& from) {\n"
-        "// @@protoc_insertion_point(generalized_copy_from_start:"
-        "$full_name$)\n");
-    format.Indent();
-
-    format("if (&from == this) return;\n");
-
-    if (!options_.opensource_runtime) {
-      // This check is disabled in the opensource release because we're
-      // concerned that many users do not define NDEBUG in their release
-      // builds.
-      format(
-          "#ifndef NDEBUG\n"
-          "size_t from_size = from.ByteSizeLong();\n"
-          "#endif\n"
-          "Clear();\n"
-          "#ifndef NDEBUG\n"
-          "$CHK$_EQ(from_size, from.ByteSizeLong())\n"
-          "  << \"Source of CopyFrom changed when clearing target.  Either \"\n"
-          "  << \"source is a nested message in target (not allowed), or \"\n"
-          "  << \"another thread is modifying the source.\";\n"
-          "#endif\n");
-    } else {
-      format("Clear();\n");
-    }
-    format("MergeFrom(from);\n");
-
-    format.Outdent();
-    format("}\n\n");
+    // We don't override the generalized CopyFrom (aka that which
+    // takes in the Message base class as a parameter); instead we just
+    // let the base Message::CopyFrom take care of it.  The base MergeFrom
+    // knows how to quickly confirm the types exactly match, and if so, will
+    // use GetClassData() to get the address of Message::CopyWithSizeCheck,
+    // which calls Clear() and then MergeFrom(), as well as making sure that
+    // clearing the destination message doesn't alter the size of the source,
+    // when in debug builds.
+    // Most callers avoid this by passing a "from" message that is the same
+    // type as the message being merged into, rather than a generic Message.
   }
 
   // Generate the class-specific CopyFrom.
@@ -3230,8 +3250,8 @@
         "#ifndef NDEBUG\n"
         "$CHK$_EQ(from_size, from.ByteSizeLong())\n"
         "  << \"Source of CopyFrom changed when clearing target.  Either \"\n"
-        "  << \"source is a nested message in target (not allowed), or \"\n"
-        "  << \"another thread is modifying the source.\";\n"
+        "     \"source is a nested message in target (not allowed), or \"\n"
+        "     \"another thread is modifying the source.\";\n"
         "#endif\n");
   } else {
     format("Clear();\n");
@@ -3329,10 +3349,11 @@
         "$uint8$* $classname$::_InternalSerialize(\n"
         "    $uint8$* target, ::$proto_ns$::io::EpsCopyOutputStream* stream) "
         "const {\n"
+        "$annotate_serialize$"
         "  target = _extensions_."
         "InternalSerializeMessageSetWithCachedSizesToArray(target, stream);\n");
     std::map<std::string, std::string> vars;
-    SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+    SetUnknownFieldsVariable(descriptor_, options_, &vars);
     format.AddMap(vars);
     format(
         "  target = ::$proto_ns$::internal::"
@@ -3347,7 +3368,8 @@
   format(
       "$uint8$* $classname$::_InternalSerialize(\n"
       "    $uint8$* target, ::$proto_ns$::io::EpsCopyOutputStream* stream) "
-      "const {\n");
+      "const {\n"
+      "$annotate_serialize$");
   format.Indent();
 
   format("// @@protoc_insertion_point(serialize_to_array_start:$full_name$)\n");
@@ -3570,7 +3592,7 @@
   }
 
   std::map<std::string, std::string> vars;
-  SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+  SetUnknownFieldsVariable(descriptor_, options_, &vars);
   format.AddMap(vars);
   format("if (PROTOBUF_PREDICT_FALSE($have_unknown_fields$)) {\n");
   format.Indent();
@@ -3662,7 +3684,7 @@
   format("}\n");
 
   std::map<std::string, std::string> vars;
-  SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+  SetUnknownFieldsVariable(descriptor_, options_, &vars);
   format.AddMap(vars);
   format("if (PROTOBUF_PREDICT_FALSE($have_unknown_fields$)) {\n");
   format.Indent();
@@ -3703,10 +3725,11 @@
   if (descriptor_->options().message_set_wire_format()) {
     // Special-case MessageSet.
     std::map<std::string, std::string> vars;
-    SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+    SetUnknownFieldsVariable(descriptor_, options_, &vars);
     format.AddMap(vars);
     format(
         "size_t $classname$::ByteSizeLong() const {\n"
+        "$annotate_bytesize$"
         "// @@protoc_insertion_point(message_set_byte_size_start:$full_name$)\n"
         "  size_t total_size = _extensions_.MessageSetByteSize();\n"
         "  if ($have_unknown_fields$) {\n"
@@ -3752,6 +3775,7 @@
 
   format(
       "size_t $classname$::ByteSizeLong() const {\n"
+      "$annotate_bytesize$"
       "// @@protoc_insertion_point(message_byte_size_start:$full_name$)\n");
   format.Indent();
   format(
@@ -3765,7 +3789,7 @@
   }
 
   std::map<std::string, std::string> vars;
-  SetUnknkownFieldsVariable(descriptor_, options_, &vars);
+  SetUnknownFieldsVariable(descriptor_, options_, &vars);
   format.AddMap(vars);
 
   // Handle required fields (if any).  We expect all of them to be
@@ -4070,3 +4094,5 @@
 }  // namespace compiler
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.cc b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
index fc7aa4a..c04c83a 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
@@ -109,7 +109,7 @@
     format(
         "$deprecated_attr$const $type$& ${1$$name$$}$() const { "
         "__builtin_trap(); }\n"
-        "PROTOBUF_FUTURE_MUST_USE_RESULT $deprecated_attr$$type$* "
+        "PROTOBUF_MUST_USE_RESULT $deprecated_attr$$type$* "
         "${1$$release_name$$}$() { "
         "__builtin_trap(); }\n"
         "$deprecated_attr$$type$* ${1$mutable_$name$$}$() { "
@@ -126,7 +126,7 @@
   }
   format(
       "$deprecated_attr$const $type$& ${1$$name$$}$() const;\n"
-      "PROTOBUF_FUTURE_MUST_USE_RESULT $deprecated_attr$$type$* "
+      "PROTOBUF_MUST_USE_RESULT $deprecated_attr$$type$* "
       "${1$$release_name$$}$();\n"
       "$deprecated_attr$$type$* ${1$mutable_$name$$}$();\n"
       "$deprecated_attr$void ${1$set_allocated_$name$$}$"
@@ -163,7 +163,7 @@
       "      $type_default_instance$);\n"
       "}\n"
       "inline const $type$& $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n");
@@ -171,7 +171,6 @@
   format(
       "inline void $classname$::unsafe_arena_set_allocated_$name$(\n"
       "    $type$* $name$) {\n"
-      "$annotate_accessor$"
       // If we're not on an arena, free whatever we were holding before.
       // (If we are on arena, we can just forget the earlier pointer.)
       "  if (GetArenaForAllocation() == nullptr) {\n"
@@ -190,12 +189,14 @@
       "  } else {\n"
       "    $clear_hasbit$\n"
       "  }\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated"
       ":$full_name$)\n"
       "}\n");
   format(
       "inline $type$* $classname$::$release_name$() {\n"
       "$type_reference_function$"
+      "$annotate_release$"
       "  $clear_hasbit$\n"
       "  $type$* temp = $casted_member$;\n"
       "  $name$_ = nullptr;\n"
@@ -205,7 +206,7 @@
       "  return temp;\n"
       "}\n"
       "inline $type$* $classname$::unsafe_arena_release_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_release$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "$type_reference_function$"
       "  $clear_hasbit$\n"
@@ -230,16 +231,16 @@
       "  return $casted_member$;\n"
       "}\n"
       "inline $type$* $classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "  $type$* _msg = _internal_mutable_$name$();\n"
+      "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
-      "  return _internal_mutable_$name$();\n"
+      "  return _msg;\n"
       "}\n");
 
   // We handle the most common case inline, and delegate less common cases to
   // the slow fallback function.
   format(
       "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
-      "$annotate_accessor$"
       "  ::$proto_ns$::Arena* message_arena = GetArenaForAllocation();\n");
   format("  if (message_arena == nullptr) {\n");
   if (IsCrossFileMessage(descriptor_)) {
@@ -281,6 +282,7 @@
     format("  $name$_ = $name$;\n");
   }
   format(
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n");
 }
@@ -494,7 +496,6 @@
   Formatter format(printer, variables_);
   format(
       "void $classname$::set_allocated_$name$($type$* $name$) {\n"
-      "$annotate_accessor$"
       "  ::$proto_ns$::Arena* message_arena = GetArenaForAllocation();\n"
       "  clear_$oneof_name$();\n"
       "  if ($name$) {\n");
@@ -521,6 +522,7 @@
       "    set_has_$name$();\n"
       "    $field_member$ = $name$;\n"
       "  }\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n");
 }
@@ -530,7 +532,7 @@
   Formatter format(printer, variables_);
   format(
       "inline $type$* $classname$::$release_name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_release$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if (_internal_has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
@@ -552,12 +554,12 @@
       "      : reinterpret_cast< $type$&>($type_default_instance$);\n"
       "}\n"
       "inline const $type$& $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
       "inline $type$* $classname$::unsafe_arena_release_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_release$"
       "  // @@protoc_insertion_point(field_unsafe_arena_release"
       ":$full_name$)\n"
       "  if (_internal_has_$name$()) {\n"
@@ -571,7 +573,6 @@
       "}\n"
       "inline void $classname$::unsafe_arena_set_allocated_$name$"
       "($type$* $name$) {\n"
-      "$annotate_accessor$"
       // We rely on the oneof clear method to free the earlier contents of
       // this oneof. We can directly use the pointer we're given to set the
       // new value.
@@ -580,6 +581,7 @@
       "    set_has_$name$();\n"
       "    $field_member$ = $name$;\n"
       "  }\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:"
       "$full_name$)\n"
       "}\n"
@@ -593,9 +595,10 @@
       "  return $field_member$;\n"
       "}\n"
       "inline $type$* $classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "  $type$* _msg = _internal_mutable_$name$();\n"
+      "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
-      "  return _internal_mutable_$name$();\n"
+      "  return _msg;\n"
       "}\n");
 }
 
@@ -701,7 +704,7 @@
 
   format(
       "inline $type$* $classname$::mutable_$name$(int index) {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable$"
       // TODO(dlj): move insertion points
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "$type_reference_function$"
@@ -709,7 +712,7 @@
       "}\n"
       "inline ::$proto_ns$::RepeatedPtrField< $type$ >*\n"
       "$classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable_list$"
       "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
       "$type_reference_function$"
       "  return &$name$_$weak$;\n"
@@ -733,7 +736,7 @@
 
   format(
       "inline const $type$& $classname$::$name$(int index) const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$(index);\n"
       "}\n"
@@ -741,15 +744,16 @@
       "  return $name$_$weak$.Add();\n"
       "}\n"
       "inline $type$* $classname$::add_$name$() {\n"
-      "$annotate_accessor$"
+      "  $type$* _add = _internal_add_$name$();\n"
+      "$annotate_add_mutable$"
       "  // @@protoc_insertion_point(field_add:$full_name$)\n"
-      "  return _internal_add_$name$();\n"
+      "  return _add;\n"
       "}\n");
 
   format(
       "inline const ::$proto_ns$::RepeatedPtrField< $type$ >&\n"
       "$classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
       "$type_reference_function$"
       "  return $name$_$weak$;\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_options.h b/src/google/protobuf/compiler/cpp/cpp_options.h
index 7aa3985..04142ee 100644
--- a/src/google/protobuf/compiler/cpp/cpp_options.h
+++ b/src/google/protobuf/compiler/cpp/cpp_options.h
@@ -74,6 +74,7 @@
     kTCTableGuarded,
     kTCTableAlways
   } tctable_mode = kTCTableNever;
+  bool inject_field_listener_events = false;
 };
 
 }  // namespace cpp
diff --git a/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc b/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
index 5dc370c..aa9500b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
@@ -30,6 +30,9 @@
 
 #include <google/protobuf/compiler/cpp/cpp_parse_function_generator.h>
 
+#include <limits>
+
+#include <google/protobuf/compiler/cpp/cpp_helpers.h>
 #include <google/protobuf/wire_format.h>
 
 namespace google {
@@ -38,6 +41,7 @@
 namespace cpp {
 
 namespace {
+using google::protobuf::internal::TcFieldData;
 using google::protobuf::internal::WireFormat;
 using google::protobuf::internal::WireFormatLite;
 
@@ -60,58 +64,222 @@
   return ctype == FieldOptions::STRING || ctype == FieldOptions::CORD;
 }
 
-bool IsTCTableEnabled(const Options& options) {
+bool IsTcTableEnabled(const Options& options) {
   return options.tctable_mode == Options::kTCTableAlways;
 }
-bool IsTCTableGuarded(const Options& options) {
+bool IsTcTableGuarded(const Options& options) {
   return options.tctable_mode == Options::kTCTableGuarded;
 }
-bool IsTCTableDisabled(const Options& options) {
+bool IsTcTableDisabled(const Options& options) {
   return options.tctable_mode == Options::kTCTableNever;
 }
 
+int TagSize(uint32_t field_number) {
+  if (field_number < 16) return 1;
+  GOOGLE_CHECK_LT(field_number, (1 << 14))
+      << "coded tag for " << field_number << " too big for uint16_t";
+  return 2;
+}
+
+const char* TagType(const FieldDescriptor* field) {
+  return CodedTagType(TagSize(field->number()));
+}
+
+std::string MessageParseFunctionName(const FieldDescriptor* field,
+                                     const Options& options) {
+  std::string name =
+      "::" + ProtobufNamespace(options) + "::internal::TcParserBase::";
+  if (field->is_repeated()) {
+    name.append("Repeated");
+  } else {
+    name.append("Singular");
+  }
+  name.append("ParseMessage<" + ClassName(field->message_type()) + ", " +
+              TagType(field) + ">");
+  return name;
+}
+
+std::string FieldParseFunctionName(const FieldDescriptor* field,
+                                   const Options& options,
+                                   uint32_t table_size_log2);
+
 }  // namespace
 
-ParseFunctionGenerator::ParseFunctionGenerator(const Descriptor* descriptor,
-                                               int num_hasbits,
-                                               const Options& options,
-                                               MessageSCCAnalyzer* scc_analyzer)
+const char* CodedTagType(int tag_size) {
+  return tag_size == 1 ? "uint8_t" : "uint16_t";
+}
+
+TailCallTableInfo::TailCallTableInfo(const Descriptor* descriptor,
+                                     const Options& options,
+                                     const std::vector<int>& has_bit_indices,
+                                     MessageSCCAnalyzer* scc_analyzer) {
+  std::vector<const FieldDescriptor*> ordered_fields =
+      GetOrderedFields(descriptor, options);
+
+  // The table size is rounded up to the nearest power of 2, clamping at 2^5.
+  // Note that this is a naive approach: a better approach should only consider
+  // table-eligible fields. We may also want to push rarely-encountered fields
+  // into the fallback, to make the table smaller.
+  table_size_log2 = ordered_fields.size() >= 16  ? 5
+                    : ordered_fields.size() >= 8 ? 4
+                    : ordered_fields.size() >= 4 ? 3
+                    : ordered_fields.size() >= 2 ? 2
+                                                 : 1;
+  const unsigned table_size = 1 << table_size_log2;
+
+  // Construct info for each possible entry. Fields that do not use table-driven
+  // parsing will still have an entry that nominates the fallback function.
+  fast_path_fields.resize(table_size);
+
+  for (const auto* field : ordered_fields) {
+    // Eagerly assume slow path. If we can handle this field on the fast path,
+    // we will pop its entry from `fallback_fields`.
+    fallback_fields.push_back(field);
+
+    // Anything difficult slow path:
+    if (field->is_map()) continue;
+    if (field->real_containing_oneof()) continue;
+    if (field->options().lazy()) continue;
+    if (field->options().weak()) continue;
+    if (IsImplicitWeakField(field, options, scc_analyzer)) continue;
+
+    // The largest tag that can be read by the tailcall parser is two bytes
+    // when varint-coded. This allows 14 bits for the numeric tag value:
+    //   byte 0   byte 1
+    //   1nnnnttt 0nnnnnnn
+    //    ^^^^^^^  ^^^^^^^
+    uint32_t tag = WireFormat::MakeTag(field);
+    if (tag >= 1 << 14) {
+      continue;
+    } else if (tag >= 1 << 7) {
+      tag = ((tag << 1) & 0x7F00) | 0x80 | (tag & 0x7F);
+    }
+    // The field index is determined by the low bits of the field number, where
+    // the table size determines the width of the mask. The largest table
+    // supported is 32 entries. The parse loop uses these bits directly, so that
+    // the dispatch does not require arithmetic:
+    //   byte 0   byte 1
+    //   1nnnnttt 0nnnnnnn
+    //   ^^^^^
+    // This means that any field number that does not fit in the lower 4 bits
+    // will always have the top bit of its table index asserted:
+    uint32_t idx = (tag >> 3) & (table_size - 1);
+    // If this entry in the table is already used, then this field will be
+    // handled by the generated fallback function.
+    if (!fast_path_fields[idx].func_name.empty()) continue;
+
+    // Determine the hasbit mask for this field, if needed. (Note that fields
+    // without hasbits use different parse functions.)
+    int hasbit_idx;
+    if (HasHasbit(field)) {
+      hasbit_idx = has_bit_indices[field->index()];
+      GOOGLE_CHECK_NE(-1, hasbit_idx) << field->DebugString();
+      // The tailcall parser can only update the first 32 hasbits. If this
+      // field's has-bit is beyond that, then it will need to be handled by the
+      // fallback parse function.
+      if (hasbit_idx >= 32) continue;
+    } else {
+      // The tailcall parser only ever syncs 32 has-bits, so if there is no
+      // presence, set a bit that will not be used.
+      hasbit_idx = 63;
+    }
+
+    // Determine the name of the fastpath parse function to use for this field.
+    std::string name;
+
+    switch (field->type()) {
+      case FieldDescriptor::TYPE_MESSAGE:
+        name = MessageParseFunctionName(field, options);
+        break;
+
+      case FieldDescriptor::TYPE_FIXED64:
+      case FieldDescriptor::TYPE_FIXED32:
+      case FieldDescriptor::TYPE_SFIXED64:
+      case FieldDescriptor::TYPE_SFIXED32:
+      case FieldDescriptor::TYPE_DOUBLE:
+      case FieldDescriptor::TYPE_FLOAT:
+        name = FieldParseFunctionName(field, options, table_size_log2);
+        break;
+
+      default:
+        break;
+    }
+
+    if (name.empty()) {
+      continue;
+    }
+    // This field made it into the fast path, so remove it from the fallback
+    // fields and fill in the table entry.
+    fallback_fields.pop_back();
+    fast_path_fields[idx].func_name = name;
+    fast_path_fields[idx].bits = TcFieldData(tag, hasbit_idx, 0);
+    fast_path_fields[idx].field = field;
+  }
+
+  // Construct a mask of has-bits for required fields numbered <= 32.
+  has_hasbits_required_mask = 0;
+  for (auto field : FieldRange(descriptor)) {
+    if (field->is_required()) {
+      int idx = has_bit_indices[field->index()];
+      if (idx >= 32) continue;
+      has_hasbits_required_mask |= 1u << idx;
+    }
+  }
+
+  // If there are no fallback fields, and at most one extension range, the
+  // parser can use a generic fallback function. Otherwise, a message-specific
+  // fallback routine is needed.
+  use_generated_fallback =
+      !fallback_fields.empty() || descriptor->extension_range_count() > 1;
+}
+
+ParseFunctionGenerator::ParseFunctionGenerator(
+    const Descriptor* descriptor, int max_has_bit_index,
+    const std::vector<int>& has_bit_indices, const Options& options,
+    MessageSCCAnalyzer* scc_analyzer,
+    const std::map<std::string, std::string>& vars)
     : descriptor_(descriptor),
       scc_analyzer_(scc_analyzer),
       options_(options),
-      num_hasbits_(num_hasbits) {
+      variables_(vars),
+      num_hasbits_(max_has_bit_index) {
+  if (IsTcTableGuarded(options_) || IsTcTableEnabled(options_)) {
+    tc_table_info_.reset(new TailCallTableInfo(descriptor_, options_,
+                                               has_bit_indices, scc_analyzer));
+  }
   SetCommonVars(options_, &variables_);
-  SetUnknkownFieldsVariable(descriptor_, options_, &variables_);
+  SetUnknownFieldsVariable(descriptor_, options_, &variables_);
   variables_["classname"] = ClassName(descriptor, false);
 }
 
 void ParseFunctionGenerator::GenerateMethodDecls(io::Printer* printer) {
   Formatter format(printer, variables_);
-  if (IsTCTableGuarded(options_)) {
+  if (IsTcTableGuarded(options_)) {
     format.Outdent();
     format("#ifdef PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
     format.Indent();
   }
-  if (IsTCTableGuarded(options_) || IsTCTableEnabled(options_)) {
-    format.Outdent();
-    format("#error Tail Call Table parsing not yet implemented.\n");
-    format.Indent();
+  if (IsTcTableGuarded(options_) || IsTcTableEnabled(options_)) {
+    if (tc_table_info_->use_generated_fallback) {
+      format(
+          "static const char* Tct_ParseFallback(\n"
+          "    ::google::protobuf::MessageLite *msg, const char *ptr,\n"
+          "    ::google::protobuf::internal::ParseContext *ctx,\n"
+          "    const ::google::protobuf::internal::TailCallParseTableBase *table,\n"
+          "    uint64_t hasbits, ::google::protobuf::internal::TcFieldData data);\n"
+          "inline const char* Tct_FallbackImpl(\n"
+          "    const char* ptr, ::$proto_ns$::internal::ParseContext* ctx,\n"
+          "    const void*, $uint64$ hasbits);\n");
+    }
   }
-  if (IsTCTableGuarded(options_)) {
-    format.Outdent();
-    format("#else\n");
-    format.Indent();
-  }
-  if (IsTCTableGuarded(options_) || IsTCTableDisabled(options_)) {
-    format(
-        "const char* _InternalParse(const char* ptr, "
-        "::$proto_ns$::internal::ParseContext* ctx) final;\n");
-  }
-  if (IsTCTableGuarded(options_)) {
+  if (IsTcTableGuarded(options_)) {
     format.Outdent();
     format("#endif\n");
     format.Indent();
   }
+  format(
+      "const char* _InternalParse(const char* ptr, "
+      "::$proto_ns$::internal::ParseContext* ctx) final;\n");
 }
 
 void ParseFunctionGenerator::GenerateMethodImpls(io::Printer* printer) {
@@ -121,24 +289,107 @@
     format(
         "const char* $classname$::_InternalParse(const char* ptr,\n"
         "                  ::$proto_ns$::internal::ParseContext* ctx) {\n"
+        "$annotate_deserialize$"
         "  return _extensions_.ParseMessageSet(ptr, \n"
         "      internal_default_instance(), &_internal_metadata_, ctx);\n"
         "}\n");
     return;
   }
-  if (IsTCTableGuarded(options_)) {
-    format("#ifdef PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
+  if (IsTcTableGuarded(options_)) {
+    format("#ifdef PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n\n");
   }
-  if (IsTCTableGuarded(options_) || IsTCTableEnabled(options_)) {
-    format("#error Tail Call Table parsing not yet implemented.\n");
+  if (IsTcTableGuarded(options_) || IsTcTableEnabled(options_)) {
+    format(
+        "const char* $classname$::_InternalParse(\n"
+        "    const char* ptr, ::$proto_ns$::internal::ParseContext* ctx) {\n"
+        "  return ::$proto_ns$::internal::TcParser<$1$>::ParseLoop(\n"
+        "      this, ptr, ctx, &_table_.header);\n"
+        "}\n"
+        "\n",
+        tc_table_info_->table_size_log2);
+    if (tc_table_info_->use_generated_fallback) {
+      GenerateTailcallFallbackFunction(format);
+    }
   }
-  if (IsTCTableGuarded(options_)) {
-    format("#else  // PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
+  if (IsTcTableGuarded(options_)) {
+    format("\n#else  // PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n\n");
   }
-  if (IsTCTableGuarded(options_) || IsTCTableDisabled(options_)) {
+  if (IsTcTableGuarded(options_) || IsTcTableDisabled(options_)) {
     GenerateLoopingParseFunction(format);
   }
-  if (IsTCTableGuarded(options_)) {
+  if (IsTcTableGuarded(options_)) {
+    format("\n#endif  // PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
+  }
+}
+
+void ParseFunctionGenerator::GenerateTailcallFallbackFunction(
+    Formatter& format) {
+  format(
+      "const char* $classname$::Tct_ParseFallback(PROTOBUF_TC_PARAM_DECL) {\n"
+      "  return static_cast<$classname$*>(msg)->Tct_FallbackImpl(ptr, ctx, "
+      "table, hasbits);\n"
+      "}\n\n");
+
+  format(
+      "const char* $classname$::Tct_FallbackImpl(const char* ptr, "
+      "::$proto_ns$::internal::ParseContext* ctx, const void*, "
+      "$uint64$ hasbits) {\n"
+      "#define CHK_(x) if (PROTOBUF_PREDICT_FALSE(!(x))) return nullptr\n");
+  format.Indent();
+
+  if (num_hasbits_ > 0) {
+    // Sync hasbits
+    format("_has_bits_[0] = hasbits;\n");
+  }
+
+  format.Set("has_bits", "_has_bits_");
+  format.Set("continue", "goto success");
+  GenerateParseIterationBody(format, descriptor_,
+                             tc_table_info_->fallback_fields);
+
+  format.Outdent();
+  format("success:\n");
+  format("  return ptr;\n");
+  format(
+      "#undef CHK_\n"
+      "}\n");
+}
+
+void ParseFunctionGenerator::GenerateDataDecls(io::Printer* printer) {
+  if (descriptor_->options().message_set_wire_format()) {
+    return;
+  }
+  Formatter format(printer, variables_);
+  if (IsTcTableGuarded(options_)) {
+    format.Outdent();
+    format("#ifdef PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
+    format.Indent();
+  }
+  if (IsTcTableGuarded(options_) || IsTcTableEnabled(options_)) {
+    format(
+        "static const ::$proto_ns$::internal::TailCallParseTable<$1$>\n"
+        "    _table_;\n",
+        tc_table_info_->table_size_log2);
+  }
+  if (IsTcTableGuarded(options_)) {
+    format.Outdent();
+    format("#endif  // PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
+    format.Indent();
+  }
+}
+
+void ParseFunctionGenerator::GenerateDataDefinitions(io::Printer* printer) {
+  if (descriptor_->options().message_set_wire_format()) {
+    return;
+  }
+  Formatter format(printer, variables_);
+  if (IsTcTableGuarded(options_)) {
+    format("#ifdef PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
+  }
+  if (IsTcTableGuarded(options_) || IsTcTableEnabled(options_)) {
+    GenerateTailCallTable(format);
+  }
+  if (IsTcTableGuarded(options_)) {
     format("#endif  // PROTOBUF_TAIL_CALL_TABLE_PARSER_ENABLED\n");
   }
 }
@@ -147,6 +398,7 @@
   format(
       "const char* $classname$::_InternalParse(const char* ptr, "
       "::$proto_ns$::internal::ParseContext* ctx) {\n"
+      "$annotate_deserialize$"
       "#define CHK_(x) if (PROTOBUF_PREDICT_FALSE(!(x))) goto failure\n");
   format.Indent();
   int hasbits_size = 0;
@@ -184,6 +436,79 @@
       "}\n");
 }
 
+void ParseFunctionGenerator::GenerateTailCallTable(Formatter& format) {
+  // All entries without a fast-path parsing function need a fallback.
+  std::string fallback;
+  if (tc_table_info_->use_generated_fallback) {
+    fallback = ClassName(descriptor_) + "::Tct_ParseFallback";
+  } else {
+    fallback = "::" + ProtobufNamespace(options_) +
+               "::internal::TcParserBase::GenericFallback";
+    if (GetOptimizeFor(descriptor_->file(), options_) ==
+        FileOptions::LITE_RUNTIME) {
+      fallback += "Lite";
+    }
+  }
+
+  // For simplicity and speed, the table is not covering all proto
+  // configurations. This model uses a fallback to cover all situations that
+  // the table can't accommodate, together with unknown fields or extensions.
+  // These are number of fields over 32, fields with 3 or more tag bytes,
+  // maps, weak fields, lazy, more than 1 extension range. In the cases
+  // the table is sufficient we can use a generic routine, that just handles
+  // unknown fields and potentially an extension range.
+  format(
+      "const ::$proto_ns$::internal::TailCallParseTable<$1$>\n"
+      "    $classname$::_table_ = {\n",
+      tc_table_info_->table_size_log2);
+  format.Indent();
+  format("{\n");
+  format.Indent();
+  if (num_hasbits_ > 0 || IsMapEntryMessage(descriptor_)) {
+    format("PROTOBUF_FIELD_OFFSET($classname$, _has_bits_),\n");
+  } else {
+    format("0,  // no _has_bits_\n");
+  }
+  if (descriptor_->extension_range_count() == 1) {
+    format(
+        "PROTOBUF_FIELD_OFFSET($classname$, _extensions_),\n"
+        "$1$, $2$,  // extension_range_{low,high}\n",
+        descriptor_->extension_range(0)->start,
+        descriptor_->extension_range(0)->end);
+  } else {
+    format("0, 0, 0,  // no _extensions_\n");
+  }
+  format(
+      "$1$,  // has_bits_required_mask\n"
+      "&$2$._instance,\n"
+      "$3$  // fallback\n",
+      tc_table_info_->has_hasbits_required_mask,
+      DefaultInstanceName(descriptor_, options_), fallback);
+  format.Outdent();
+  format("}, {\n");
+  format.Indent();
+  for (const auto& info : tc_table_info_->fast_path_fields) {
+    if (info.field != nullptr) {
+      PrintFieldComment(format, info.field);
+    }
+    format("{$1$, ", info.func_name.empty() ? fallback : info.func_name);
+    if (info.bits.data) {
+      GOOGLE_DCHECK_NE(nullptr, info.field);
+      format(
+          "{$1$, $2$, "
+          "static_cast<uint16_t>(PROTOBUF_FIELD_OFFSET($classname$, $3$_))}",
+          info.bits.coded_tag(), info.bits.hasbit_idx(), FieldName(info.field));
+    } else {
+      format("{}");
+    }
+    format("},\n");
+  }
+  format.Outdent();
+  format("},\n");  // entries[]
+  format.Outdent();
+  format("};\n\n");  // _table_
+}
+
 void ParseFunctionGenerator::GenerateArenaString(Formatter& format,
                                                  const FieldDescriptor* field) {
   if (HasHasbit(field)) {
@@ -611,6 +936,174 @@
   if (!ordered_fields.empty()) format("}  // switch\n");
 }
 
+namespace {
+
+std::string FieldParseFunctionName(const FieldDescriptor* field,
+                                   const Options& options,
+                                   uint32_t table_size_log2) {
+  ParseCardinality card =  //
+      field->is_packed()               ? ParseCardinality::kPacked
+      : field->is_repeated()           ? ParseCardinality::kRepeated
+      : field->real_containing_oneof() ? ParseCardinality::kOneof
+                                       : ParseCardinality::kSingular;
+
+  TypeFormat type_format;
+  switch (field->type()) {
+    case FieldDescriptor::TYPE_FIXED64:
+    case FieldDescriptor::TYPE_SFIXED64:
+    case FieldDescriptor::TYPE_DOUBLE:
+      type_format = TypeFormat::kFixed64;
+      break;
+
+    case FieldDescriptor::TYPE_FIXED32:
+    case FieldDescriptor::TYPE_SFIXED32:
+    case FieldDescriptor::TYPE_FLOAT:
+      type_format = TypeFormat::kFixed32;
+      break;
+
+    case FieldDescriptor::TYPE_INT64:
+    case FieldDescriptor::TYPE_UINT64:
+      type_format = TypeFormat::kVar64;
+      break;
+
+    case FieldDescriptor::TYPE_INT32:
+    case FieldDescriptor::TYPE_UINT32:
+      type_format = TypeFormat::kVar32;
+      break;
+
+    case FieldDescriptor::TYPE_SINT64:
+      type_format = TypeFormat::kSInt64;
+      break;
+
+    case FieldDescriptor::TYPE_SINT32:
+      type_format = TypeFormat::kSInt32;
+      break;
+
+    case FieldDescriptor::TYPE_BOOL:
+      type_format = TypeFormat::kBool;
+      break;
+
+    case FieldDescriptor::TYPE_BYTES:
+      type_format = TypeFormat::kBytes;
+      break;
+
+    case FieldDescriptor::TYPE_STRING:
+      type_format = TypeFormat::kString;
+      break;
+
+    default:
+      GOOGLE_LOG(DFATAL) << "Type not handled: " << field->DebugString();
+      return "";
+  }
+
+  return "::" + ProtobufNamespace(options) + "::internal::" +
+         GetTailCallFieldHandlerName(card, type_format, table_size_log2,
+                                     TagSize(field->number()));
+}
+
+}  // namespace
+
+std::string GetTailCallFieldHandlerName(ParseCardinality card,
+                                        TypeFormat type_format,
+                                        int table_size_log2,
+                                        int tag_length_bytes) {
+  std::string name;
+
+  switch (card) {
+    case ParseCardinality::kPacked:
+    case ParseCardinality::kRepeated:
+      name = "TcParserBase::";
+      break;
+
+    case ParseCardinality::kSingular:
+    case ParseCardinality::kOneof:
+      switch (type_format) {
+        case TypeFormat::kBytes:
+        case TypeFormat::kString:
+        case TypeFormat::kStringValidateOnly:
+          name = "TcParserBase::";
+          break;
+
+        default:
+          name = StrCat("TcParser<", table_size_log2, ">::");
+          break;
+      }
+  }
+
+  // The field implementation functions are prefixed by cardinality:
+  //   `Singular` for optional or implicit fields.
+  //   `Repeated` for non-packed repeated.
+  //   `Packed` for packed repeated.
+  switch (card) {
+    case ParseCardinality::kSingular:
+      name.append("Singular");
+      break;
+    case ParseCardinality::kOneof:
+      name.append("Oneof");
+      break;
+    case ParseCardinality::kRepeated:
+      name.append("Repeated");
+      break;
+    case ParseCardinality::kPacked:
+      name.append("Packed");
+      break;
+  }
+
+  // Next in the function name is the TypeFormat-specific name.
+  switch (type_format) {
+    case TypeFormat::kFixed64:
+    case TypeFormat::kFixed32:
+      name.append("Fixed");
+      break;
+
+    default:
+      break;
+  }
+
+  name.append("<");
+
+  // Determine the numeric layout type for the parser to use, independent of
+  // the specific parsing logic used.
+  switch (type_format) {
+    case TypeFormat::kVar64:
+    case TypeFormat::kFixed64:
+      name.append("uint64_t");
+      break;
+
+    case TypeFormat::kSInt64:
+      name.append("int64_t");
+      break;
+
+    case TypeFormat::kVar32:
+    case TypeFormat::kFixed32:
+      name.append("uint32_t");
+      break;
+
+    case TypeFormat::kSInt32:
+      name.append("int32_t");
+      break;
+
+    case TypeFormat::kBool:
+      name.append("bool");
+      break;
+
+    default:
+      GOOGLE_LOG(FATAL) << static_cast<int>(type_format);
+      return "";
+  }
+
+  name.append(", ");
+  name.append(CodedTagType(tag_length_bytes));
+
+  switch (type_format) {
+    default:
+      break;
+  }
+
+  name.append(">");
+  return name;
+}
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.h b/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.h
index 704af4a..00719a8 100644
--- a/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.h
+++ b/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.h
@@ -39,6 +39,7 @@
 #include <google/protobuf/compiler/cpp/cpp_options.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.h>
+#include <google/protobuf/generated_message_tctable_decl.h>
 #include <google/protobuf/wire_format_lite.h>
 
 namespace google {
@@ -46,13 +47,38 @@
 namespace compiler {
 namespace cpp {
 
+// Helper class for generating tailcall parsing functions.
+struct TailCallTableInfo {
+  TailCallTableInfo(const Descriptor* descriptor, const Options& options,
+                    const std::vector<int>& has_bit_indices,
+                    MessageSCCAnalyzer* scc_analyzer);
+  // Information to generate field entries.
+  struct FieldInfo {
+    const FieldDescriptor* field;
+    google::protobuf::internal::TcFieldData bits;
+    std::string func_name;
+  };
+  // Fields parsed by the table fast-path.
+  std::vector<FieldInfo> fast_path_fields;
+  // Fields parsed by slow-path fallback.
+  std::vector<const FieldDescriptor*> fallback_fields;
+  // Table size.
+  int table_size_log2;
+  // Mask for has-bits of required fields.
+  uint32_t has_hasbits_required_mask;
+  // True if a generated fallback function is required instead of generic.
+  bool use_generated_fallback;
+};
+
 // ParseFunctionGenerator generates the _InternalParse function for a message
 // (and any associated supporting members).
 class ParseFunctionGenerator {
  public:
-  ParseFunctionGenerator(const Descriptor* descriptor, int num_hasbits,
+  ParseFunctionGenerator(const Descriptor* descriptor, int max_has_bit_index,
+                         const std::vector<int>& has_bit_indices,
                          const Options& options,
-                         MessageSCCAnalyzer* scc_analyzer);
+                         MessageSCCAnalyzer* scc_analyzer,
+                         const std::map<std::string, std::string>& vars);
 
   // Emits class-level method declarations to `printer`:
   void GenerateMethodDecls(io::Printer* printer);
@@ -60,13 +86,22 @@
   // Emits out-of-class method implementation definitions to `printer`:
   void GenerateMethodImpls(io::Printer* printer);
 
+  // Emits class-level data member declarations to `printer`:
+  void GenerateDataDecls(io::Printer* printer);
+
+  // Emits out-of-class data member definitions to `printer`:
+  void GenerateDataDefinitions(io::Printer* printer);
+
  private:
-  // Returns the proto runtime internal namespace.
-  std::string pi_ns();
+  // Generates a fallback function for tailcall table-based parsing.
+  void GenerateTailcallFallbackFunction(Formatter& format);
 
   // Generates a looping `_InternalParse` function.
   void GenerateLoopingParseFunction(Formatter& format);
 
+  // Generates the tail-call table definition.
+  void GenerateTailCallTable(Formatter& format);
+
   // Generates parsing code for an `ArenaString` field.
   void GenerateArenaString(Formatter& format, const FieldDescriptor* field);
 
@@ -92,9 +127,50 @@
   MessageSCCAnalyzer* scc_analyzer_;
   const Options& options_;
   std::map<std::string, std::string> variables_;
+  std::unique_ptr<TailCallTableInfo> tc_table_info_;
   int num_hasbits_;
 };
 
+// Returns the integer type that holds a tag of the given length (in bytes) when
+// wire-encoded.
+const char* CodedTagType(int tag_size);
+
+enum class ParseCardinality {
+  kSingular,
+  kOneof,
+  kRepeated,
+  kPacked,
+};
+
+// TypeFormat defines parsing types, which encapsulates the expected wire
+// format, conversion or validation, and the in-memory layout.
+enum class TypeFormat {
+  // Fixed types:
+  kFixed64,  // fixed64, sfixed64, double
+  kFixed32,  // fixed32, sfixed32, float
+
+  // Varint types:
+  kVar64,   // int64, uint64
+  kVar32,   // int32, uint32
+  kSInt64,  // sint64
+  kSInt32,  // sint32
+  kBool,    // bool
+
+  // Length-delimited types:
+  kBytes,               // bytes
+  kString,              // string (proto3/UTF-8 strict)
+  kStringValidateOnly,  // string (proto2/UTF-8 validate only)
+};
+
+// Returns the name of a field parser function.
+//
+// These are out-of-line functions generated by
+// parse_function_inc_generator_main.
+std::string GetTailCallFieldHandlerName(ParseCardinality card,
+                                        TypeFormat type_format,
+                                        int table_size_log2,
+                                        int tag_length_bytes);
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
index 9f7f61e..98ba8a6 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
@@ -153,7 +153,7 @@
       "  return $name$_;\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
@@ -162,8 +162,8 @@
       "  $name$_ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
-      "$annotate_accessor$"
       "  _internal_set_$name$(value);\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n");
 }
@@ -252,13 +252,13 @@
       "  $field_member$ = value;\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
-      "$annotate_accessor$"
       "  _internal_set_$name$(value);\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n");
 }
@@ -338,12 +338,12 @@
       "  return $name$_.Get(index);\n"
       "}\n"
       "inline $type$ $classname$::$name$(int index) const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$(index);\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, $type$ value) {\n"
-      "$annotate_accessor$"
+      "$annotate_set$"
       "  $name$_.Set(index, value);\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
@@ -351,8 +351,8 @@
       "  $name$_.Add(value);\n"
       "}\n"
       "inline void $classname$::add_$name$($type$ value) {\n"
-      "$annotate_accessor$"
       "  _internal_add_$name$(value);\n"
+      "$annotate_add$"
       "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "}\n"
       "inline const ::$proto_ns$::RepeatedField< $type$ >&\n"
@@ -361,7 +361,7 @@
       "}\n"
       "inline const ::$proto_ns$::RepeatedField< $type$ >&\n"
       "$classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
@@ -371,7 +371,7 @@
       "}\n"
       "inline ::$proto_ns$::RepeatedField< $type$ >*\n"
       "$classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable_list$"
       "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
       "  return _internal_mutable_$name$();\n"
       "}\n");
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.cc b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
index c68a090..5c7bb68 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
@@ -162,7 +162,7 @@
       descriptor_);
   format(
       "$deprecated_attr$std::string* ${1$mutable_$name$$}$();\n"
-      "PROTOBUF_FUTURE_MUST_USE_RESULT $deprecated_attr$std::string* "
+      "PROTOBUF_MUST_USE_RESULT $deprecated_attr$std::string* "
       "${1$$release_name$$}$();\n"
       "$deprecated_attr$void ${1$set_allocated_$name$$}$(std::string* "
       "$name$);\n",
@@ -187,7 +187,7 @@
   Formatter format(printer, variables_);
   format(
       "inline const std::string& $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n");
   if (!descriptor_->default_value_string().empty()) {
     format(
@@ -200,16 +200,17 @@
       "template <typename ArgT0, typename... ArgT>\n"
       "inline PROTOBUF_ALWAYS_INLINE\n"
       "void $classname$::set_$name$(ArgT0&& arg0, ArgT... args) {\n"
-      "$annotate_accessor$"
       " $set_hasbit$\n"
       " $name$_.$setter$($default_value_tag$, static_cast<ArgT0 &&>(arg0),"
       " args..., GetArenaForAllocation());\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline std::string* $classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "  std::string* _s = _internal_mutable_$name$();\n"
+      "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
-      "  return _internal_mutable_$name$();\n"
+      "  return _s;\n"
       "}\n"
       "inline const std::string& $classname$::_internal_$name$() const {\n"
       "  return $name$_.Get();\n"
@@ -226,7 +227,7 @@
       "GetArenaForAllocation());\n"
       "}\n"
       "inline std::string* $classname$::$release_name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_release$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n");
 
   if (HasHasbit(descriptor_)) {
@@ -245,7 +246,6 @@
   format(
       "}\n"
       "inline void $classname$::set_allocated_$name$(std::string* $name$) {\n"
-      "$annotate_accessor$"
       "  if ($name$ != nullptr) {\n"
       "    $set_hasbit$\n"
       "  } else {\n"
@@ -253,6 +253,7 @@
       "  }\n"
       "  $name$_.SetAllocated($init_value$, $name$,\n"
       "      GetArenaForAllocation());\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n");
 }
@@ -404,13 +405,12 @@
   Formatter format(printer, variables_);
   format(
       "inline const std::string& $classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$();\n"
       "}\n"
       "template <typename ArgT0, typename... ArgT>\n"
       "inline void $classname$::set_$name$(ArgT0&& arg0, ArgT... args) {\n"
-      "$annotate_accessor$"
       "  if (!_internal_has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -418,12 +418,14 @@
       "  }\n"
       "  $field_member$.$setter$($default_value_tag$,"
       " static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline std::string* $classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "  std::string* _s = _internal_mutable_$name$();\n"
+      "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
-      "  return _internal_mutable_$name$();\n"
+      "  return _s;\n"
       "}\n"
       "inline const std::string& $classname$::_internal_$name$() const {\n"
       "  if (_internal_has_$name$()) {\n"
@@ -452,7 +454,7 @@
       "      $default_variable_or_tag$, GetArenaForAllocation());\n"
       "}\n"
       "inline std::string* $classname$::$release_name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_release$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if (_internal_has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
@@ -463,7 +465,6 @@
       "  }\n"
       "}\n"
       "inline void $classname$::set_allocated_$name$(std::string* $name$) {\n"
-      "$annotate_accessor$"
       "  if (has_$oneof_name$()) {\n"
       "    clear_$oneof_name$();\n"
       "  }\n"
@@ -475,6 +476,7 @@
       "      arena->Own($name$);\n"
       "    }\n"
       "  }\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n");
 }
@@ -590,9 +592,10 @@
   Formatter format(printer, variables_);
   format(
       "inline std::string* $classname$::add_$name$() {\n"
-      "$annotate_accessor$"
+      "  std::string* _s = _internal_add_$name$();\n"
+      "$annotate_add_mutable$"
       "  // @@protoc_insertion_point(field_add_mutable:$full_name$)\n"
-      "  return _internal_add_$name$();\n"
+      "  return _s;\n"
       "}\n");
   if (options_.safe_boundary_check) {
     format(
@@ -610,39 +613,39 @@
   }
   format(
       "inline const std::string& $classname$::$name$(int index) const {\n"
-      "$annotate_accessor$"
+      "$annotate_get$"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return _internal_$name$(index);\n"
       "}\n"
       "inline std::string* $classname$::mutable_$name$(int index) {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $name$_.Mutable(index);\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, const std::string& "
       "value) "
       "{\n"
-      "$annotate_accessor$"
-      "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "  $name$_.Mutable(index)->assign(value);\n"
+      "$annotate_set$"
+      "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, std::string&& value) {\n"
-      "$annotate_accessor$"
-      "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "  $name$_.Mutable(index)->assign(std::move(value));\n"
+      "$annotate_set$"
+      "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, const char* value) {\n"
-      "$annotate_accessor$"
       "  $null_check$"
       "  $name$_.Mutable(index)->assign(value);\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
       "}\n");
   if (!options_.opensource_runtime) {
     format(
         "inline void "
         "$classname$::set_$name$(int index, StringPiece value) {\n"
-        "$annotate_accessor$"
         "  $name$_.Mutable(index)->assign(value.data(), value.size());\n"
+        "$annotate_set$"
         "  // @@protoc_insertion_point(field_set_string_piece:$full_name$)\n"
         "}\n");
   }
@@ -650,54 +653,54 @@
       "inline void "
       "$classname$::set_$name$"
       "(int index, const $pointer_type$* value, size_t size) {\n"
-      "$annotate_accessor$"
       "  $name$_.Mutable(index)->assign(\n"
       "    reinterpret_cast<const char*>(value), size);\n"
+      "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
       "}\n"
       "inline std::string* $classname$::_internal_add_$name$() {\n"
       "  return $name$_.Add();\n"
       "}\n"
       "inline void $classname$::add_$name$(const std::string& value) {\n"
-      "$annotate_accessor$"
       "  $name$_.Add()->assign(value);\n"
+      "$annotate_add$"
       "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "}\n"
       "inline void $classname$::add_$name$(std::string&& value) {\n"
-      "$annotate_accessor$"
       "  $name$_.Add(std::move(value));\n"
+      "$annotate_add$"
       "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "}\n"
       "inline void $classname$::add_$name$(const char* value) {\n"
-      "$annotate_accessor$"
       "  $null_check$"
       "  $name$_.Add()->assign(value);\n"
+      "$annotate_add$"
       "  // @@protoc_insertion_point(field_add_char:$full_name$)\n"
       "}\n");
   if (!options_.opensource_runtime) {
     format(
         "inline void $classname$::add_$name$(StringPiece value) {\n"
-        "$annotate_accessor$"
         "  $name$_.Add()->assign(value.data(), value.size());\n"
+        "$annotate_add$"
         "  // @@protoc_insertion_point(field_add_string_piece:$full_name$)\n"
         "}\n");
   }
   format(
       "inline void "
       "$classname$::add_$name$(const $pointer_type$* value, size_t size) {\n"
-      "$annotate_accessor$"
       "  $name$_.Add()->assign(reinterpret_cast<const char*>(value), size);\n"
+      "$annotate_add$"
       "  // @@protoc_insertion_point(field_add_pointer:$full_name$)\n"
       "}\n"
       "inline const ::$proto_ns$::RepeatedPtrField<std::string>&\n"
       "$classname$::$name$() const {\n"
-      "$annotate_accessor$"
+      "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
       "  return $name$_;\n"
       "}\n"
       "inline ::$proto_ns$::RepeatedPtrField<std::string>*\n"
       "$classname$::mutable_$name$() {\n"
-      "$annotate_accessor$"
+      "$annotate_mutable_list$"
       "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
       "  return &$name$_;\n"
       "}\n");
diff --git a/src/google/protobuf/compiler/importer.h b/src/google/protobuf/compiler/importer.h
index 6cdae8a..08a49c5 100644
--- a/src/google/protobuf/compiler/importer.h
+++ b/src/google/protobuf/compiler/importer.h
@@ -202,8 +202,8 @@
   virtual void AddError(const std::string& filename, int line, int column,
                         const std::string& message) = 0;
 
-  virtual void AddWarning(const std::string& /* filename */, int /* line */, int /* column */,
-                          const std::string& /* message */) {}
+  virtual void AddWarning(const std::string& /* filename */, int /* line */,
+                          int /* column */, const std::string& /* message */) {}
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MultiFileErrorCollector);
diff --git a/src/google/protobuf/compiler/java/java_enum_field.h b/src/google/protobuf/compiler/java/java_enum_field.h
index a8cd033..5d4e2a7 100644
--- a/src/google/protobuf/compiler/java/java_enum_field.h
+++ b/src/google/protobuf/compiler/java/java_enum_field.h
@@ -60,29 +60,30 @@
   explicit ImmutableEnumFieldGenerator(const FieldDescriptor* descriptor,
                                        int messageBitIndex, int builderBitIndex,
                                        Context* context);
-  ~ImmutableEnumFieldGenerator();
+  ~ImmutableEnumFieldGenerator() override;
 
   // implements ImmutableFieldGenerator
   // ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
@@ -119,29 +120,30 @@
   explicit RepeatedImmutableEnumFieldGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex,
       int builderBitIndex, Context* context);
-  ~RepeatedImmutableEnumFieldGenerator();
+  ~RepeatedImmutableEnumFieldGenerator() override;
 
   // implements ImmutableFieldGenerator ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingCodeFromPacked(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingCodeFromPacked(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_enum_field_lite.h b/src/google/protobuf/compiler/java/java_enum_field_lite.h
index 99249fe..6ed11c9 100644
--- a/src/google/protobuf/compiler/java/java_enum_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_enum_field_lite.h
@@ -62,20 +62,20 @@
   explicit ImmutableEnumFieldLiteGenerator(const FieldDescriptor* descriptor,
                                            int messageBitIndex,
                                            Context* context);
-  ~ImmutableEnumFieldLiteGenerator();
+  ~ImmutableEnumFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator
   // ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
@@ -93,12 +93,12 @@
  public:
   ImmutableEnumOneofFieldLiteGenerator(const FieldDescriptor* descriptor,
                                        int messageBitIndex, Context* context);
-  ~ImmutableEnumOneofFieldLiteGenerator();
+  ~ImmutableEnumOneofFieldLiteGenerator() override;
 
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
+                         std::vector<uint16_t>* output) const override;
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ImmutableEnumOneofFieldLiteGenerator);
@@ -109,19 +109,19 @@
  public:
   explicit RepeatedImmutableEnumFieldLiteGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex, Context* context);
-  ~RepeatedImmutableEnumFieldLiteGenerator();
+  ~RepeatedImmutableEnumFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_field.cc b/src/google/protobuf/compiler/java/java_field.cc
index db5a332..8916d13 100644
--- a/src/google/protobuf/compiler/java/java_field.cc
+++ b/src/google/protobuf/compiler/java/java_field.cc
@@ -263,6 +263,20 @@
   (*variables)["kt_capitalized_name"] = IsForbiddenKotlin(info->name)
                                             ? info->capitalized_name + "_"
                                             : info->capitalized_name;
+  if (!descriptor->is_repeated()) {
+    (*variables)["annotation_field_type"] = FieldTypeName(descriptor->type());
+  } else if (GetJavaType(descriptor) == JAVATYPE_MESSAGE &&
+             IsMapEntry(descriptor->message_type())) {
+    (*variables)["annotation_field_type"] =
+        std::string(FieldTypeName(descriptor->type())) + "MAP";
+  } else {
+    (*variables)["annotation_field_type"] =
+        std::string(FieldTypeName(descriptor->type())) + "_LIST";
+    if (descriptor->is_packed()) {
+      (*variables)["annotation_field_type"] =
+          (*variables)["annotation_field_type"] + "_PACKED";
+    }
+  }
 }
 
 void SetCommonOneofVariables(const FieldDescriptor* descriptor,
diff --git a/src/google/protobuf/compiler/java/java_file.cc b/src/google/protobuf/compiler/java/java_file.cc
index e8801a1..9dbf818 100644
--- a/src/google/protobuf/compiler/java/java_file.cc
+++ b/src/google/protobuf/compiler/java/java_file.cc
@@ -686,7 +686,7 @@
   for (int i = 0; i < file_->message_type_count(); i++) {
     const Descriptor* descriptor = file_->message_type(i);
     MessageGenerator* generator = message_generators_[i].get();
-    auto open_file = [context](const string& filename) {
+    auto open_file = [context](const std::string& filename) {
       return std::unique_ptr<io::ZeroCopyOutputStream>(context->Open(filename));
     };
     std::string filename = package_dir + descriptor->name() + "Kt.kt";
diff --git a/src/google/protobuf/compiler/java/java_helpers.cc b/src/google/protobuf/compiler/java/java_helpers.cc
index 1020043..f37ecde 100644
--- a/src/google/protobuf/compiler/java/java_helpers.cc
+++ b/src/google/protobuf/compiler/java/java_helpers.cc
@@ -91,17 +91,6 @@
         "transient",  "try",          "void",      "volatile",   "while",
     });
 
-// Names that should be avoided as field names in Kotlin.
-// All Kotlin hard keywords are in this list.
-const std::unordered_set<std::string>* kKotlinForbiddenNames =
-    new std::unordered_set<std::string>({
-        "as",    "as?",   "break", "class",  "continue",  "do",     "else",
-        "false", "for",   "fun",   "if",     "in",        "!in",    "interface",
-        "is",    "!is",   "null",  "object", "package",   "return", "super",
-        "this",  "throw", "true",  "try",    "typealias", "typeof", "val",
-        "var",   "when",  "while",
-    });
-
 bool IsForbidden(const std::string& field_name) {
   for (int i = 0; i < GOOGLE_ARRAYSIZE(kForbiddenWordList); ++i) {
     if (field_name == kForbiddenWordList[i]) {
@@ -167,38 +156,6 @@
       StrCat(enum_verifier_string, terminating_string).c_str());
 }
 
-std::string ToCamelCase(const std::string& input, bool lower_first) {
-  bool capitalize_next = !lower_first;
-  std::string result;
-  result.reserve(input.size());
-
-  for (char i : input) {
-    if (i == '_') {
-      capitalize_next = true;
-    } else if (capitalize_next) {
-      result.push_back(ToUpperCh(i));
-      capitalize_next = false;
-    } else {
-      result.push_back(i);
-    }
-  }
-
-  // Lower-case the first letter.
-  if (lower_first && !result.empty()) {
-    result[0] = ToLowerCh(result[0]);
-  }
-
-  return result;
-}
-
-char ToUpperCh(char ch) {
-  return (ch >= 'a' && ch <= 'z') ? (ch - 'a' + 'A') : ch;
-}
-
-char ToLowerCh(char ch) {
-  return (ch >= 'A' && ch <= 'Z') ? (ch - 'A' + 'a') : ch;
-}
-
 std::string UnderscoresToCamelCase(const std::string& input,
                                    bool cap_next_letter) {
   GOOGLE_CHECK(!input.empty());
@@ -236,6 +193,38 @@
   return result;
 }
 
+std::string ToCamelCase(const std::string& input, bool lower_first) {
+  bool capitalize_next = !lower_first;
+  std::string result;
+  result.reserve(input.size());
+
+  for (char i : input) {
+    if (i == '_') {
+      capitalize_next = true;
+    } else if (capitalize_next) {
+      result.push_back(ToUpperCh(i));
+      capitalize_next = false;
+    } else {
+      result.push_back(i);
+    }
+  }
+
+  // Lower-case the first letter.
+  if (lower_first && !result.empty()) {
+    result[0] = ToLowerCh(result[0]);
+  }
+
+  return result;
+}
+
+char ToUpperCh(char ch) {
+  return (ch >= 'a' && ch <= 'z') ? (ch - 'a' + 'A') : ch;
+}
+
+char ToLowerCh(char ch) {
+  return (ch >= 'A' && ch <= 'Z') ? (ch - 'A' + 'a') : ch;
+}
+
 std::string UnderscoresToCamelCase(const FieldDescriptor* field) {
   return UnderscoresToCamelCase(FieldName(field), false);
 }
@@ -261,6 +250,17 @@
 }
 
 bool IsForbiddenKotlin(const std::string& field_name) {
+  // Names that should be avoided as field names in Kotlin.
+  // All Kotlin hard keywords are in this list.
+  const std::unordered_set<std::string>* kKotlinForbiddenNames =
+      new std::unordered_set<std::string>({
+          "as",      "as?",       "break",  "class", "continue", "do",
+          "else",    "false",     "for",    "fun",   "if",       "in",
+          "!in",     "interface", "is",     "!is",   "null",     "object",
+          "package", "return",    "super",  "this",  "throw",    "true",
+          "try",     "typealias", "typeof", "val",   "var",      "when",
+          "while",
+      });
   return kKotlinForbiddenNames->find(field_name) !=
          kKotlinForbiddenNames->end();
 }
@@ -499,7 +499,6 @@
   return NULL;
 }
 
-
 std::string GetOneofStoredType(const FieldDescriptor* field) {
   const JavaType javaType = GetJavaType(field);
   switch (javaType) {
diff --git a/src/google/protobuf/compiler/java/java_kotlin_generator.cc b/src/google/protobuf/compiler/java/java_kotlin_generator.cc
index 5a5d198..8d262a0 100644
--- a/src/google/protobuf/compiler/java/java_kotlin_generator.cc
+++ b/src/google/protobuf/compiler/java/java_kotlin_generator.cc
@@ -1,12 +1,40 @@
-#include <google/protobuf/compiler/java/java_kotlin_generator.h>
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#include <memory>
+#include <google/protobuf/compiler/java/java_kotlin_generator.h>
 
 #include <google/protobuf/compiler/java/java_file.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/compiler/java/java_options.h>
-
-#include <google/protobuf/stubs/strutil.h>
+#include <google/protobuf/compiler/java/java_generator.h>
+#include <google/protobuf/compiler/code_generator.h>
 
 namespace google {
 namespace protobuf {
@@ -63,13 +91,17 @@
   std::vector<std::string> all_files;
   std::vector<std::string> all_annotations;
 
-  std::unique_ptr<FileGenerator> file_generator(new FileGenerator(file, file_options, /* immutable_api = */ true));
+  std::unique_ptr<FileGenerator> file_generator;
+  if (file_options.generate_immutable_code) {
+    file_generator.reset(
+        new FileGenerator(file, file_options, /* immutable_api = */ true));
+  }
 
   if (!file_generator->Validate(error)) {
     return false;
   }
 
-  auto open_file = [context](const string& filename) {
+  auto open_file = [context](const std::string& filename) {
     return std::unique_ptr<io::ZeroCopyOutputStream>(context->Open(filename));
   };
   std::string package_dir = JavaPackageToDir(file_generator->java_package());
@@ -126,5 +158,5 @@
 
 }  // namespace java
 }  // namespace compiler
-} //namespace protobuf
+}  // namespace protobuf
 }  // namespace google
diff --git a/src/google/protobuf/compiler/java/java_kotlin_generator.h b/src/google/protobuf/compiler/java/java_kotlin_generator.h
index db15353..66e32b9 100644
--- a/src/google/protobuf/compiler/java/java_kotlin_generator.h
+++ b/src/google/protobuf/compiler/java/java_kotlin_generator.h
@@ -1,9 +1,41 @@
-#ifndef GOOGLE_PROTOBUF_COMPILER_JAVA_KOTLIN_GENERATOR_H_
-#define GOOGLE_PROTOBUF_COMPILER_JAVA_KOTLIN_GENERATOR_H_
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Generates Kotlin code for a given .proto file.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_JAVA_KOTLIN_GENERATOR_H__
+#define GOOGLE_PROTOBUF_COMPILER_JAVA_KOTLIN_GENERATOR_H__
 
 #include <string>
-#include <google/protobuf/compiler/code_generator.h>
 
+#include <google/protobuf/compiler/code_generator.h>
 #include <google/protobuf/port_def.inc>
 
 namespace google {
@@ -37,4 +69,4 @@
 
 #include <google/protobuf/port_undef.inc>
 
-#endif  // GOOGLE_PROTOBUF_COMPILER_JAVA_KOTLIN_GENERATOR_H_
+#endif  // GOOGLE_PROTOBUF_COMPILER_JAVA_KOTLIN_GENERATOR_H__
diff --git a/src/google/protobuf/compiler/java/java_map_field.h b/src/google/protobuf/compiler/java/java_map_field.h
index 63b2577..b52b7e9 100644
--- a/src/google/protobuf/compiler/java/java_map_field.h
+++ b/src/google/protobuf/compiler/java/java_map_field.h
@@ -43,26 +43,27 @@
   explicit ImmutableMapFieldGenerator(const FieldDescriptor* descriptor,
                                       int messageBitIndex, int builderBitIndex,
                                       Context* context);
-  ~ImmutableMapFieldGenerator();
+  ~ImmutableMapFieldGenerator() override;
 
   // implements ImmutableFieldGenerator ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
   std::string GetBoxedType() const;
 
diff --git a/src/google/protobuf/compiler/java/java_map_field_lite.h b/src/google/protobuf/compiler/java/java_map_field_lite.h
index 62c162d..da046b2 100644
--- a/src/google/protobuf/compiler/java/java_map_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_map_field_lite.h
@@ -45,19 +45,19 @@
   explicit ImmutableMapFieldLiteGenerator(const FieldDescriptor* descriptor,
                                           int messageBitIndex,
                                           Context* context);
-  ~ImmutableMapFieldLiteGenerator();
+  ~ImmutableMapFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_message.cc b/src/google/protobuf/compiler/java/java_message.cc
index 69528ec..9059bfa 100644
--- a/src/google/protobuf/compiler/java/java_message.cc
+++ b/src/google/protobuf/compiler/java/java_message.cc
@@ -1367,6 +1367,41 @@
   }
 }
 
+// ===================================================================
+void ImmutableMessageGenerator::GenerateMutableCopy(io::Printer* printer) {
+  printer->Print(
+      "protected com.google.protobuf.MutableMessage\n"
+      "    internalMutableDefault() {\n"
+      "  return MutableDefaultLoader.get();\n"
+      "}\n"
+      "\n"
+      "private static final class MutableDefaultLoader {\n"
+      "  private static final java.lang.Object defaultOrRuntimeException;\n"
+      "  static {\n"
+      "    java.lang.Object local;\n"
+      "    try {\n"
+      "      local = internalMutableDefault(\"$mutable_name$\");\n"
+      "    } catch (java.lang.RuntimeException e) {\n"
+      "      local = e;\n"
+      "    }\n"
+      "    defaultOrRuntimeException = local;\n"
+      "  }\n"
+      "\n"
+      "  private MutableDefaultLoader() {}\n"
+      "\n"
+      "  public static com.google.protobuf.MutableMessage get() {\n"
+      "    if (defaultOrRuntimeException\n"
+      "         instanceof java.lang.RuntimeException) {\n"
+      "      throw (java.lang.RuntimeException) defaultOrRuntimeException;\n"
+      "    }\n"
+      "    return\n"
+      "        (com.google.protobuf.MutableMessage) "
+      "defaultOrRuntimeException;\n"
+      "  }\n"
+      "}\n",
+      "mutable_name", name_resolver_->GetJavaMutableClassName(descriptor_));
+}
+
 void ImmutableMessageGenerator::GenerateKotlinDsl(io::Printer* printer) const {
   printer->Print(
       "@kotlin.OptIn"
diff --git a/src/google/protobuf/compiler/java/java_message.h b/src/google/protobuf/compiler/java/java_message.h
index 50d7180..cafc91e 100644
--- a/src/google/protobuf/compiler/java/java_message.h
+++ b/src/google/protobuf/compiler/java/java_message.h
@@ -102,14 +102,14 @@
   ImmutableMessageGenerator(const Descriptor* descriptor, Context* context);
   virtual ~ImmutableMessageGenerator();
 
-  virtual void Generate(io::Printer* printer);
-  virtual void GenerateInterface(io::Printer* printer);
-  virtual void GenerateExtensionRegistrationCode(io::Printer* printer);
-  virtual void GenerateStaticVariables(io::Printer* printer,
-                                       int* bytecode_estimate);
+  void Generate(io::Printer* printer) override;
+  void GenerateInterface(io::Printer* printer) override;
+  void GenerateExtensionRegistrationCode(io::Printer* printer) override;
+  void GenerateStaticVariables(io::Printer* printer,
+                               int* bytecode_estimate) override;
 
   // Returns an estimate of the number of bytes the printed code will compile to
-  virtual int GenerateStaticVariableInitializers(io::Printer* printer);
+  int GenerateStaticVariableInitializers(io::Printer* printer) override;
   void GenerateKotlinDsl(io::Printer* printer) const override;
   void GenerateKotlinMembers(io::Printer* printer) const override;
   void GenerateTopLevelKotlinMembers(io::Printer* printer) const override;
@@ -134,6 +134,7 @@
   void GenerateEqualsAndHashCode(io::Printer* printer);
   void GenerateParser(io::Printer* printer);
   void GenerateParsingConstructor(io::Printer* printer);
+  void GenerateMutableCopy(io::Printer* printer);
   void GenerateKotlinExtensions(io::Printer* printer) const;
   void GenerateAnyMethods(io::Printer* printer);
 
diff --git a/src/google/protobuf/compiler/java/java_message_field.h b/src/google/protobuf/compiler/java/java_message_field.h
index 08c5e91..891bcc6 100644
--- a/src/google/protobuf/compiler/java/java_message_field.h
+++ b/src/google/protobuf/compiler/java/java_message_field.h
@@ -128,28 +128,29 @@
   explicit RepeatedImmutableMessageFieldGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex,
       int builderBitIndex, Context* context);
-  ~RepeatedImmutableMessageFieldGenerator();
+  ~RepeatedImmutableMessageFieldGenerator() override;
 
   // implements ImmutableFieldGenerator ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_message_field_lite.h b/src/google/protobuf/compiler/java/java_message_field_lite.h
index af0129c..3195b09 100644
--- a/src/google/protobuf/compiler/java/java_message_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_message_field_lite.h
@@ -109,19 +109,19 @@
  public:
   explicit RepeatedImmutableMessageFieldLiteGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex, Context* context);
-  ~RepeatedImmutableMessageFieldLiteGenerator();
+  ~RepeatedImmutableMessageFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_name_resolver.cc b/src/google/protobuf/compiler/java/java_name_resolver.cc
index 43c7db5..39bf3e2 100644
--- a/src/google/protobuf/compiler/java/java_name_resolver.cc
+++ b/src/google/protobuf/compiler/java/java_name_resolver.cc
@@ -350,6 +350,29 @@
                           descriptor->file(), true, true, true);
 }
 
+std::string ClassNameResolver::GetJavaMutableClassName(
+    const Descriptor* descriptor) {
+  return GetJavaClassFullName(ClassNameWithoutPackage(descriptor, false),
+                              descriptor->file(), false);
+}
+
+std::string ClassNameResolver::GetJavaMutableClassName(
+    const EnumDescriptor* descriptor) {
+  return GetJavaClassFullName(ClassNameWithoutPackage(descriptor, false),
+                              descriptor->file(), false);
+}
+
+std::string ClassNameResolver::GetDowngradedFileClassName(
+    const FileDescriptor* file) {
+  return "Downgraded" + GetFileClassName(file, false);
+}
+
+std::string ClassNameResolver::GetDowngradedClassName(
+    const Descriptor* descriptor) {
+  return FileJavaPackage(descriptor->file()) + "." +
+         GetDowngradedFileClassName(descriptor->file()) + "." +
+         ClassNameWithoutPackage(descriptor, false);
+}
 
 }  // namespace java
 }  // namespace compiler
diff --git a/src/google/protobuf/compiler/java/java_name_resolver.h b/src/google/protobuf/compiler/java/java_name_resolver.h
index 9717d92..a688d49 100644
--- a/src/google/protobuf/compiler/java/java_name_resolver.h
+++ b/src/google/protobuf/compiler/java/java_name_resolver.h
@@ -117,6 +117,12 @@
   std::string GetJavaImmutableClassName(const EnumDescriptor* descriptor);
   std::string GetKotlinFactoryName(const Descriptor* descriptor);
   std::string GetKotlinExtensionsClassName(const Descriptor* descriptor);
+  std::string GetJavaMutableClassName(const Descriptor* descriptor);
+  std::string GetJavaMutableClassName(const EnumDescriptor* descriptor);
+  // Gets the outer class and the actual class for downgraded mutable messages.
+  std::string GetDowngradedFileClassName(const FileDescriptor* file);
+  std::string GetDowngradedClassName(const Descriptor* descriptor);
+
  private:
   // Get the full name of a Java class by prepending the Java package name
   // or outer class name.
diff --git a/src/google/protobuf/compiler/java/java_primitive_field.cc b/src/google/protobuf/compiler/java/java_primitive_field.cc
index 2bc565c..dfd7188 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field.cc
+++ b/src/google/protobuf/compiler/java/java_primitive_field.cc
@@ -54,7 +54,6 @@
 namespace java {
 
 using internal::WireFormat;
-using internal::WireFormatLite;
 
 namespace {
 
diff --git a/src/google/protobuf/compiler/java/java_primitive_field.h b/src/google/protobuf/compiler/java/java_primitive_field.h
index 56be916..535c1f1 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field.h
+++ b/src/google/protobuf/compiler/java/java_primitive_field.h
@@ -61,29 +61,30 @@
                                             int messageBitIndex,
                                             int builderBitIndex,
                                             Context* context);
-  ~ImmutablePrimitiveFieldGenerator();
+  ~ImmutablePrimitiveFieldGenerator() override;
 
   // implements ImmutableFieldGenerator
   // ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
@@ -120,29 +121,30 @@
   explicit RepeatedImmutablePrimitiveFieldGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex,
       int builderBitIndex, Context* context);
-  virtual ~RepeatedImmutablePrimitiveFieldGenerator();
+  ~RepeatedImmutablePrimitiveFieldGenerator() override;
 
   // implements ImmutableFieldGenerator ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingCodeFromPacked(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingCodeFromPacked(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_primitive_field_lite.h b/src/google/protobuf/compiler/java/java_primitive_field_lite.h
index b9fcacd..d3744b1 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_primitive_field_lite.h
@@ -62,20 +62,20 @@
  public:
   explicit ImmutablePrimitiveFieldLiteGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex, Context* context);
-  ~ImmutablePrimitiveFieldLiteGenerator();
+  ~ImmutablePrimitiveFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator
   // ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
@@ -110,19 +110,19 @@
  public:
   explicit RepeatedImmutablePrimitiveFieldLiteGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex, Context* context);
-  virtual ~RepeatedImmutablePrimitiveFieldLiteGenerator();
+  ~RepeatedImmutablePrimitiveFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
-      
-  std::string GetBoxedType() const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
+
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_string_field.h b/src/google/protobuf/compiler/java/java_string_field.h
index 6cc9126..a98ea54 100644
--- a/src/google/protobuf/compiler/java/java_string_field.h
+++ b/src/google/protobuf/compiler/java/java_string_field.h
@@ -119,28 +119,29 @@
   explicit RepeatedImmutableStringFieldGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex,
       int builderBitIndex, Context* context);
-  ~RepeatedImmutableStringFieldGenerator();
+  ~RepeatedImmutableStringFieldGenerator() override;
 
   // implements ImmutableFieldGenerator ---------------------------------------
-  int GetNumBitsForMessage() const;
-  int GetNumBitsForBuilder() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
-  void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingDoneCode(io::Printer* printer) const;
-  void GenerateSerializationCode(io::Printer* printer) const;
-  void GenerateSerializedSizeCode(io::Printer* printer) const;
-  void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
-  void GenerateEqualsCode(io::Printer* printer) const;
-  void GenerateHashCode(io::Printer* printer) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  int GetNumBitsForBuilder() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
+  void GenerateBuilderClearCode(io::Printer* printer) const override;
+  void GenerateMergingCode(io::Printer* printer) const override;
+  void GenerateBuildingCode(io::Printer* printer) const override;
+  void GenerateParsingCode(io::Printer* printer) const override;
+  void GenerateParsingDoneCode(io::Printer* printer) const override;
+  void GenerateSerializationCode(io::Printer* printer) const override;
+  void GenerateSerializedSizeCode(io::Printer* printer) const override;
+  void GenerateFieldBuilderInitializationCode(
+      io::Printer* printer) const override;
+  void GenerateEqualsCode(io::Printer* printer) const override;
+  void GenerateHashCode(io::Printer* printer) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/java/java_string_field_lite.h b/src/google/protobuf/compiler/java/java_string_field_lite.h
index c95256f..85ec602 100644
--- a/src/google/protobuf/compiler/java/java_string_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_string_field_lite.h
@@ -63,20 +63,20 @@
   explicit ImmutableStringFieldLiteGenerator(const FieldDescriptor* descriptor,
                                              int messageBitIndex,
                                              Context* context);
-  ~ImmutableStringFieldLiteGenerator();
+  ~ImmutableStringFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator
   // ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  protected:
   const FieldDescriptor* descriptor_;
@@ -93,13 +93,13 @@
  public:
   ImmutableStringOneofFieldLiteGenerator(const FieldDescriptor* descriptor,
                                          int messageBitIndex, Context* context);
-  ~ImmutableStringOneofFieldLiteGenerator();
+  ~ImmutableStringOneofFieldLiteGenerator() override;
 
  private:
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
+                         std::vector<uint16_t>* output) const override;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ImmutableStringOneofFieldLiteGenerator);
 };
@@ -109,19 +109,19 @@
  public:
   explicit RepeatedImmutableStringFieldLiteGenerator(
       const FieldDescriptor* descriptor, int messageBitIndex, Context* context);
-  ~RepeatedImmutableStringFieldLiteGenerator();
+  ~RepeatedImmutableStringFieldLiteGenerator() override;
 
   // implements ImmutableFieldLiteGenerator ------------------------------------
-  int GetNumBitsForMessage() const;
-  void GenerateInterfaceMembers(io::Printer* printer) const;
-  void GenerateMembers(io::Printer* printer) const;
-  void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateInitializationCode(io::Printer* printer) const;
+  int GetNumBitsForMessage() const override;
+  void GenerateInterfaceMembers(io::Printer* printer) const override;
+  void GenerateMembers(io::Printer* printer) const override;
+  void GenerateBuilderMembers(io::Printer* printer) const override;
+  void GenerateInitializationCode(io::Printer* printer) const override;
   void GenerateFieldInfo(io::Printer* printer,
-                         std::vector<uint16_t>* output) const;
-  void GenerateKotlinDslMembers(io::Printer* printer) const;
+                         std::vector<uint16_t>* output) const override;
+  void GenerateKotlinDslMembers(io::Printer* printer) const override;
 
-  std::string GetBoxedType() const;
+  std::string GetBoxedType() const override;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index 11715d2..fec62ed 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -230,10 +230,13 @@
   }
 };
 
-Version::Version(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Version::Version(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.Version)
 }
 Version::Version(const Version& from)
@@ -251,7 +254,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.Version)
 }
 
-void Version::SharedCtor() {
+inline void Version::SharedCtor() {
 suffix_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&major_) - reinterpret_cast<char*>(this)),
@@ -261,11 +264,12 @@
 
 Version::~Version() {
   // @@protoc_insertion_point(destructor:google.protobuf.compiler.Version)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Version::SharedDtor() {
+inline void Version::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   suffix_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -456,25 +460,22 @@
   return total_size;
 }
 
-void Version::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.Version)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Version* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Version>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.Version)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.Version)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Version::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Version::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Version::GetClassData() const { return &_class_data_; }
+
+void Version::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Version *>(to)->MergeFrom(
+      static_cast<const Version &>(from));
 }
 
+
 void Version::MergeFrom(const Version& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.Version)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -494,13 +495,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void Version::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.Version)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Version::CopyFrom(const Version& from) {
@@ -558,12 +553,15 @@
 void CodeGeneratorRequest::clear_proto_file() {
   proto_file_.Clear();
 }
-CodeGeneratorRequest::CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+CodeGeneratorRequest::CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   file_to_generate_(arena),
   proto_file_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.CodeGeneratorRequest)
 }
 CodeGeneratorRequest::CodeGeneratorRequest(const CodeGeneratorRequest& from)
@@ -585,18 +583,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.CodeGeneratorRequest)
 }
 
-void CodeGeneratorRequest::SharedCtor() {
+inline void CodeGeneratorRequest::SharedCtor() {
 parameter_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 compiler_version_ = nullptr;
 }
 
 CodeGeneratorRequest::~CodeGeneratorRequest() {
   // @@protoc_insertion_point(destructor:google.protobuf.compiler.CodeGeneratorRequest)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void CodeGeneratorRequest::SharedDtor() {
+inline void CodeGeneratorRequest::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   parameter_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete compiler_version_;
@@ -811,25 +810,22 @@
   return total_size;
 }
 
-void CodeGeneratorRequest::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.CodeGeneratorRequest)
-  GOOGLE_DCHECK_NE(&from, this);
-  const CodeGeneratorRequest* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<CodeGeneratorRequest>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.CodeGeneratorRequest)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.CodeGeneratorRequest)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData CodeGeneratorRequest::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    CodeGeneratorRequest::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*CodeGeneratorRequest::GetClassData() const { return &_class_data_; }
+
+void CodeGeneratorRequest::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<CodeGeneratorRequest *>(to)->MergeFrom(
+      static_cast<const CodeGeneratorRequest &>(from));
 }
 
+
 void CodeGeneratorRequest::MergeFrom(const CodeGeneratorRequest& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.CodeGeneratorRequest)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -844,13 +840,7 @@
       _internal_mutable_compiler_version()->PROTOBUF_NAMESPACE_ID::compiler::Version::MergeFrom(from._internal_compiler_version());
     }
   }
-}
-
-void CodeGeneratorRequest::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.CodeGeneratorRequest)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void CodeGeneratorRequest::CopyFrom(const CodeGeneratorRequest& from) {
@@ -913,10 +903,13 @@
   if (generated_code_info_ != nullptr) generated_code_info_->Clear();
   _has_bits_[0] &= ~0x00000008u;
 }
-CodeGeneratorResponse_File::CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+CodeGeneratorResponse_File::CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.CodeGeneratorResponse.File)
 }
 CodeGeneratorResponse_File::CodeGeneratorResponse_File(const CodeGeneratorResponse_File& from)
@@ -946,7 +939,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.CodeGeneratorResponse.File)
 }
 
-void CodeGeneratorResponse_File::SharedCtor() {
+inline void CodeGeneratorResponse_File::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 insertion_point_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 content_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -955,11 +948,12 @@
 
 CodeGeneratorResponse_File::~CodeGeneratorResponse_File() {
   // @@protoc_insertion_point(destructor:google.protobuf.compiler.CodeGeneratorResponse.File)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void CodeGeneratorResponse_File::SharedDtor() {
+inline void CodeGeneratorResponse_File::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   insertion_point_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -1175,25 +1169,22 @@
   return total_size;
 }
 
-void CodeGeneratorResponse_File::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
-  GOOGLE_DCHECK_NE(&from, this);
-  const CodeGeneratorResponse_File* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<CodeGeneratorResponse_File>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.CodeGeneratorResponse.File)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.CodeGeneratorResponse.File)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData CodeGeneratorResponse_File::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    CodeGeneratorResponse_File::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*CodeGeneratorResponse_File::GetClassData() const { return &_class_data_; }
+
+void CodeGeneratorResponse_File::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<CodeGeneratorResponse_File *>(to)->MergeFrom(
+      static_cast<const CodeGeneratorResponse_File &>(from));
 }
 
+
 void CodeGeneratorResponse_File::MergeFrom(const CodeGeneratorResponse_File& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -1212,13 +1203,7 @@
       _internal_mutable_generated_code_info()->PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo::MergeFrom(from._internal_generated_code_info());
     }
   }
-}
-
-void CodeGeneratorResponse_File::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void CodeGeneratorResponse_File::CopyFrom(const CodeGeneratorResponse_File& from) {
@@ -1273,11 +1258,14 @@
   }
 };
 
-CodeGeneratorResponse::CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+CodeGeneratorResponse::CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   file_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.CodeGeneratorResponse)
 }
 CodeGeneratorResponse::CodeGeneratorResponse(const CodeGeneratorResponse& from)
@@ -1294,18 +1282,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.CodeGeneratorResponse)
 }
 
-void CodeGeneratorResponse::SharedCtor() {
+inline void CodeGeneratorResponse::SharedCtor() {
 error_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 supported_features_ = uint64_t{0u};
 }
 
 CodeGeneratorResponse::~CodeGeneratorResponse() {
   // @@protoc_insertion_point(destructor:google.protobuf.compiler.CodeGeneratorResponse)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void CodeGeneratorResponse::SharedDtor() {
+inline void CodeGeneratorResponse::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   error_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -1478,25 +1467,22 @@
   return total_size;
 }
 
-void CodeGeneratorResponse::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse)
-  GOOGLE_DCHECK_NE(&from, this);
-  const CodeGeneratorResponse* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<CodeGeneratorResponse>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.CodeGeneratorResponse)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.CodeGeneratorResponse)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData CodeGeneratorResponse::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    CodeGeneratorResponse::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*CodeGeneratorResponse::GetClassData() const { return &_class_data_; }
+
+void CodeGeneratorResponse::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<CodeGeneratorResponse *>(to)->MergeFrom(
+      static_cast<const CodeGeneratorResponse &>(from));
 }
 
+
 void CodeGeneratorResponse::MergeFrom(const CodeGeneratorResponse& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -1511,13 +1497,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void CodeGeneratorResponse::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.CodeGeneratorResponse)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void CodeGeneratorResponse::CopyFrom(const CodeGeneratorResponse& from) {
diff --git a/src/google/protobuf/compiler/plugin.pb.h b/src/google/protobuf/compiler/plugin.pb.h
index 0cb7941..89898c1 100644
--- a/src/google/protobuf/compiler/plugin.pb.h
+++ b/src/google/protobuf/compiler/plugin.pb.h
@@ -190,10 +190,13 @@
   Version* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Version>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Version& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Version& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -213,12 +216,16 @@
     return "google.protobuf.compiler.Version";
   }
   protected:
-  explicit Version(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Version(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -241,7 +248,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_suffix(ArgT0&& arg0, ArgT... args);
   std::string* mutable_suffix();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_suffix();
+  PROTOBUF_MUST_USE_RESULT std::string* release_suffix();
   void set_allocated_suffix(std::string* suffix);
   private:
   const std::string& _internal_suffix() const;
@@ -384,10 +391,13 @@
   CodeGeneratorRequest* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<CodeGeneratorRequest>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const CodeGeneratorRequest& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const CodeGeneratorRequest& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -407,12 +417,16 @@
     return "google.protobuf.compiler.CodeGeneratorRequest";
   }
   protected:
-  explicit CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -477,7 +491,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_parameter(ArgT0&& arg0, ArgT... args);
   std::string* mutable_parameter();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_parameter();
+  PROTOBUF_MUST_USE_RESULT std::string* release_parameter();
   void set_allocated_parameter(std::string* parameter);
   private:
   const std::string& _internal_parameter() const;
@@ -492,7 +506,7 @@
   public:
   void clear_compiler_version();
   const PROTOBUF_NAMESPACE_ID::compiler::Version& compiler_version() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::compiler::Version* release_compiler_version();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::compiler::Version* release_compiler_version();
   PROTOBUF_NAMESPACE_ID::compiler::Version* mutable_compiler_version();
   void set_allocated_compiler_version(PROTOBUF_NAMESPACE_ID::compiler::Version* compiler_version);
   private:
@@ -599,10 +613,13 @@
   CodeGeneratorResponse_File* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<CodeGeneratorResponse_File>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const CodeGeneratorResponse_File& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const CodeGeneratorResponse_File& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -622,12 +639,16 @@
     return "google.protobuf.compiler.CodeGeneratorResponse.File";
   }
   protected:
-  explicit CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -650,7 +671,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -668,7 +689,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_insertion_point(ArgT0&& arg0, ArgT... args);
   std::string* mutable_insertion_point();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_insertion_point();
+  PROTOBUF_MUST_USE_RESULT std::string* release_insertion_point();
   void set_allocated_insertion_point(std::string* insertion_point);
   private:
   const std::string& _internal_insertion_point() const;
@@ -686,7 +707,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_content(ArgT0&& arg0, ArgT... args);
   std::string* mutable_content();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_content();
+  PROTOBUF_MUST_USE_RESULT std::string* release_content();
   void set_allocated_content(std::string* content);
   private:
   const std::string& _internal_content() const;
@@ -701,7 +722,7 @@
   public:
   void clear_generated_code_info();
   const PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo& generated_code_info() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* release_generated_code_info();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* release_generated_code_info();
   PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* mutable_generated_code_info();
   void set_allocated_generated_code_info(PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* generated_code_info);
   private:
@@ -808,10 +829,13 @@
   CodeGeneratorResponse* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<CodeGeneratorResponse>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const CodeGeneratorResponse& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const CodeGeneratorResponse& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -831,12 +855,16 @@
     return "google.protobuf.compiler.CodeGeneratorResponse";
   }
   protected:
-  explicit CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -908,7 +936,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_error(ArgT0&& arg0, ArgT... args);
   std::string* mutable_error();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_error();
+  PROTOBUF_MUST_USE_RESULT std::string* release_error();
   void set_allocated_error(std::string* error);
   private:
   const std::string& _internal_error() const;
@@ -1062,8 +1090,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.Version.suffix)
 }
 inline std::string* Version::mutable_suffix() {
+  std::string* _s = _internal_mutable_suffix();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.Version.suffix)
-  return _internal_mutable_suffix();
+  return _s;
 }
 inline const std::string& Version::_internal_suffix() const {
   return suffix_.Get();
@@ -1110,8 +1139,9 @@
   file_to_generate_.Clear();
 }
 inline std::string* CodeGeneratorRequest::add_file_to_generate() {
+  std::string* _s = _internal_add_file_to_generate();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
-  return _internal_add_file_to_generate();
+  return _s;
 }
 inline const std::string& CodeGeneratorRequest::_internal_file_to_generate(int index) const {
   return file_to_generate_.Get(index);
@@ -1125,12 +1155,12 @@
   return file_to_generate_.Mutable(index);
 }
 inline void CodeGeneratorRequest::set_file_to_generate(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
   file_to_generate_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
 }
 inline void CodeGeneratorRequest::set_file_to_generate(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
   file_to_generate_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
 }
 inline void CodeGeneratorRequest::set_file_to_generate(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
@@ -1197,8 +1227,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorRequest.parameter)
 }
 inline std::string* CodeGeneratorRequest::mutable_parameter() {
+  std::string* _s = _internal_mutable_parameter();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorRequest.parameter)
-  return _internal_mutable_parameter();
+  return _s;
 }
 inline const std::string& CodeGeneratorRequest::_internal_parameter() const {
   return parameter_.Get();
@@ -1257,8 +1288,9 @@
   return proto_file_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::FileDescriptorProto* CodeGeneratorRequest::add_proto_file() {
+  PROTOBUF_NAMESPACE_ID::FileDescriptorProto* _add = _internal_add_proto_file();
   // @@protoc_insertion_point(field_add:google.protobuf.compiler.CodeGeneratorRequest.proto_file)
-  return _internal_add_proto_file();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::FileDescriptorProto >&
 CodeGeneratorRequest::proto_file() const {
@@ -1326,8 +1358,9 @@
   return compiler_version_;
 }
 inline PROTOBUF_NAMESPACE_ID::compiler::Version* CodeGeneratorRequest::mutable_compiler_version() {
+  PROTOBUF_NAMESPACE_ID::compiler::Version* _msg = _internal_mutable_compiler_version();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorRequest.compiler_version)
-  return _internal_mutable_compiler_version();
+  return _msg;
 }
 inline void CodeGeneratorRequest::set_allocated_compiler_version(PROTOBUF_NAMESPACE_ID::compiler::Version* compiler_version) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -1377,8 +1410,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.File.name)
 }
 inline std::string* CodeGeneratorResponse_File::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorResponse.File.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& CodeGeneratorResponse_File::_internal_name() const {
   return name_.Get();
@@ -1434,8 +1468,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
 }
 inline std::string* CodeGeneratorResponse_File::mutable_insertion_point() {
+  std::string* _s = _internal_mutable_insertion_point();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
-  return _internal_mutable_insertion_point();
+  return _s;
 }
 inline const std::string& CodeGeneratorResponse_File::_internal_insertion_point() const {
   return insertion_point_.Get();
@@ -1491,8 +1526,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.File.content)
 }
 inline std::string* CodeGeneratorResponse_File::mutable_content() {
+  std::string* _s = _internal_mutable_content();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorResponse.File.content)
-  return _internal_mutable_content();
+  return _s;
 }
 inline const std::string& CodeGeneratorResponse_File::_internal_content() const {
   return content_.Get();
@@ -1580,8 +1616,9 @@
   return generated_code_info_;
 }
 inline PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* CodeGeneratorResponse_File::mutable_generated_code_info() {
+  PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* _msg = _internal_mutable_generated_code_info();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorResponse.File.generated_code_info)
-  return _internal_mutable_generated_code_info();
+  return _msg;
 }
 inline void CodeGeneratorResponse_File::set_allocated_generated_code_info(PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo* generated_code_info) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -1633,8 +1670,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.error)
 }
 inline std::string* CodeGeneratorResponse::mutable_error() {
+  std::string* _s = _internal_mutable_error();
   // @@protoc_insertion_point(field_mutable:google.protobuf.compiler.CodeGeneratorResponse.error)
-  return _internal_mutable_error();
+  return _s;
 }
 inline const std::string& CodeGeneratorResponse::_internal_error() const {
   return error_.Get();
@@ -1724,8 +1762,9 @@
   return file_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::compiler::CodeGeneratorResponse_File* CodeGeneratorResponse::add_file() {
+  PROTOBUF_NAMESPACE_ID::compiler::CodeGeneratorResponse_File* _add = _internal_add_file();
   // @@protoc_insertion_point(field_add:google.protobuf.compiler.CodeGeneratorResponse.file)
-  return _internal_add_file();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::compiler::CodeGeneratorResponse_File >&
 CodeGeneratorResponse::file() const {
diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index 9fb0dfa..8aef94c 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -1238,11 +1238,14 @@
  public:
 };
 
-FileDescriptorSet::FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+FileDescriptorSet::FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   file_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FileDescriptorSet)
 }
 FileDescriptorSet::FileDescriptorSet(const FileDescriptorSet& from)
@@ -1252,16 +1255,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FileDescriptorSet)
 }
 
-void FileDescriptorSet::SharedCtor() {
+inline void FileDescriptorSet::SharedCtor() {
 }
 
 FileDescriptorSet::~FileDescriptorSet() {
   // @@protoc_insertion_point(destructor:google.protobuf.FileDescriptorSet)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FileDescriptorSet::SharedDtor() {
+inline void FileDescriptorSet::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -1372,36 +1376,27 @@
   return total_size;
 }
 
-void FileDescriptorSet::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FileDescriptorSet)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FileDescriptorSet* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FileDescriptorSet>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FileDescriptorSet)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FileDescriptorSet)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FileDescriptorSet::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FileDescriptorSet::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FileDescriptorSet::GetClassData() const { return &_class_data_; }
+
+void FileDescriptorSet::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FileDescriptorSet *>(to)->MergeFrom(
+      static_cast<const FileDescriptorSet &>(from));
 }
 
+
 void FileDescriptorSet::MergeFrom(const FileDescriptorSet& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FileDescriptorSet)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   file_.MergeFrom(from.file_);
-}
-
-void FileDescriptorSet::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FileDescriptorSet)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FileDescriptorSet::CopyFrom(const FileDescriptorSet& from) {
@@ -1460,8 +1455,9 @@
 FileDescriptorProto::_Internal::source_code_info(const FileDescriptorProto* msg) {
   return *msg->source_code_info_;
 }
-FileDescriptorProto::FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+FileDescriptorProto::FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   dependency_(arena),
   message_type_(arena),
   enum_type_(arena),
@@ -1470,7 +1466,9 @@
   public_dependency_(arena),
   weak_dependency_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FileDescriptorProto)
 }
 FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
@@ -1512,7 +1510,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FileDescriptorProto)
 }
 
-void FileDescriptorProto::SharedCtor() {
+inline void FileDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 package_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 syntax_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -1524,11 +1522,12 @@
 
 FileDescriptorProto::~FileDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.FileDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FileDescriptorProto::SharedDtor() {
+inline void FileDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   package_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -1980,25 +1979,22 @@
   return total_size;
 }
 
-void FileDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FileDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FileDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FileDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FileDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FileDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FileDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FileDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FileDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void FileDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FileDescriptorProto *>(to)->MergeFrom(
+      static_cast<const FileDescriptorProto &>(from));
 }
 
+
 void FileDescriptorProto::MergeFrom(const FileDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FileDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -2027,13 +2023,7 @@
       _internal_mutable_source_code_info()->PROTOBUF_NAMESPACE_ID::SourceCodeInfo::MergeFrom(from._internal_source_code_info());
     }
   }
-}
-
-void FileDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FileDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FileDescriptorProto::CopyFrom(const FileDescriptorProto& from) {
@@ -2115,10 +2105,13 @@
 DescriptorProto_ExtensionRange::_Internal::options(const DescriptorProto_ExtensionRange* msg) {
   return *msg->options_;
 }
-DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DescriptorProto.ExtensionRange)
 }
 DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(const DescriptorProto_ExtensionRange& from)
@@ -2136,7 +2129,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DescriptorProto.ExtensionRange)
 }
 
-void DescriptorProto_ExtensionRange::SharedCtor() {
+inline void DescriptorProto_ExtensionRange::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&options_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&end_) -
@@ -2145,11 +2138,12 @@
 
 DescriptorProto_ExtensionRange::~DescriptorProto_ExtensionRange() {
   // @@protoc_insertion_point(destructor:google.protobuf.DescriptorProto.ExtensionRange)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void DescriptorProto_ExtensionRange::SharedDtor() {
+inline void DescriptorProto_ExtensionRange::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   if (this != internal_default_instance()) delete options_;
 }
@@ -2314,25 +2308,22 @@
   return total_size;
 }
 
-void DescriptorProto_ExtensionRange::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DescriptorProto.ExtensionRange)
-  GOOGLE_DCHECK_NE(&from, this);
-  const DescriptorProto_ExtensionRange* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<DescriptorProto_ExtensionRange>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DescriptorProto.ExtensionRange)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DescriptorProto.ExtensionRange)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData DescriptorProto_ExtensionRange::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    DescriptorProto_ExtensionRange::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*DescriptorProto_ExtensionRange::GetClassData() const { return &_class_data_; }
+
+void DescriptorProto_ExtensionRange::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<DescriptorProto_ExtensionRange *>(to)->MergeFrom(
+      static_cast<const DescriptorProto_ExtensionRange &>(from));
 }
 
+
 void DescriptorProto_ExtensionRange::MergeFrom(const DescriptorProto_ExtensionRange& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DescriptorProto.ExtensionRange)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -2349,13 +2340,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void DescriptorProto_ExtensionRange::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DescriptorProto.ExtensionRange)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void DescriptorProto_ExtensionRange::CopyFrom(const DescriptorProto_ExtensionRange& from) {
@@ -2403,10 +2388,13 @@
   }
 };
 
-DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DescriptorProto.ReservedRange)
 }
 DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(const DescriptorProto_ReservedRange& from)
@@ -2419,7 +2407,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DescriptorProto.ReservedRange)
 }
 
-void DescriptorProto_ReservedRange::SharedCtor() {
+inline void DescriptorProto_ReservedRange::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&start_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&end_) -
@@ -2428,11 +2416,12 @@
 
 DescriptorProto_ReservedRange::~DescriptorProto_ReservedRange() {
   // @@protoc_insertion_point(destructor:google.protobuf.DescriptorProto.ReservedRange)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void DescriptorProto_ReservedRange::SharedDtor() {
+inline void DescriptorProto_ReservedRange::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -2570,25 +2559,22 @@
   return total_size;
 }
 
-void DescriptorProto_ReservedRange::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DescriptorProto.ReservedRange)
-  GOOGLE_DCHECK_NE(&from, this);
-  const DescriptorProto_ReservedRange* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<DescriptorProto_ReservedRange>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DescriptorProto.ReservedRange)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DescriptorProto.ReservedRange)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData DescriptorProto_ReservedRange::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    DescriptorProto_ReservedRange::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*DescriptorProto_ReservedRange::GetClassData() const { return &_class_data_; }
+
+void DescriptorProto_ReservedRange::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<DescriptorProto_ReservedRange *>(to)->MergeFrom(
+      static_cast<const DescriptorProto_ReservedRange &>(from));
 }
 
+
 void DescriptorProto_ReservedRange::MergeFrom(const DescriptorProto_ReservedRange& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DescriptorProto.ReservedRange)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -2602,13 +2588,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void DescriptorProto_ReservedRange::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DescriptorProto.ReservedRange)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void DescriptorProto_ReservedRange::CopyFrom(const DescriptorProto_ReservedRange& from) {
@@ -2658,8 +2638,9 @@
 DescriptorProto::_Internal::options(const DescriptorProto* msg) {
   return *msg->options_;
 }
-DescriptorProto::DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+DescriptorProto::DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   field_(arena),
   nested_type_(arena),
   enum_type_(arena),
@@ -2669,7 +2650,9 @@
   reserved_range_(arena),
   reserved_name_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DescriptorProto)
 }
 DescriptorProto::DescriptorProto(const DescriptorProto& from)
@@ -2697,18 +2680,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DescriptorProto)
 }
 
-void DescriptorProto::SharedCtor() {
+inline void DescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 options_ = nullptr;
 }
 
 DescriptorProto::~DescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.DescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void DescriptorProto::SharedDtor() {
+inline void DescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete options_;
@@ -3091,25 +3075,22 @@
   return total_size;
 }
 
-void DescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const DescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<DescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData DescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    DescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*DescriptorProto::GetClassData() const { return &_class_data_; }
+
+void DescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<DescriptorProto *>(to)->MergeFrom(
+      static_cast<const DescriptorProto &>(from));
 }
 
+
 void DescriptorProto::MergeFrom(const DescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -3130,13 +3111,7 @@
       _internal_mutable_options()->PROTOBUF_NAMESPACE_ID::MessageOptions::MergeFrom(from._internal_options());
     }
   }
-}
-
-void DescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void DescriptorProto::CopyFrom(const DescriptorProto& from) {
@@ -3191,12 +3166,15 @@
  public:
 };
 
-ExtensionRangeOptions::ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+ExtensionRangeOptions::ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ExtensionRangeOptions)
 }
 ExtensionRangeOptions::ExtensionRangeOptions(const ExtensionRangeOptions& from)
@@ -3207,16 +3185,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ExtensionRangeOptions)
 }
 
-void ExtensionRangeOptions::SharedCtor() {
+inline void ExtensionRangeOptions::SharedCtor() {
 }
 
 ExtensionRangeOptions::~ExtensionRangeOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.ExtensionRangeOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void ExtensionRangeOptions::SharedDtor() {
+inline void ExtensionRangeOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -3340,37 +3319,28 @@
   return total_size;
 }
 
-void ExtensionRangeOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ExtensionRangeOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const ExtensionRangeOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<ExtensionRangeOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ExtensionRangeOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ExtensionRangeOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData ExtensionRangeOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    ExtensionRangeOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*ExtensionRangeOptions::GetClassData() const { return &_class_data_; }
+
+void ExtensionRangeOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<ExtensionRangeOptions *>(to)->MergeFrom(
+      static_cast<const ExtensionRangeOptions &>(from));
 }
 
+
 void ExtensionRangeOptions::MergeFrom(const ExtensionRangeOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ExtensionRangeOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
-}
-
-void ExtensionRangeOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ExtensionRangeOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void ExtensionRangeOptions::CopyFrom(const ExtensionRangeOptions& from) {
@@ -3447,10 +3417,13 @@
 FieldDescriptorProto::_Internal::options(const FieldDescriptorProto* msg) {
   return *msg->options_;
 }
-FieldDescriptorProto::FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+FieldDescriptorProto::FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FieldDescriptorProto)
 }
 FieldDescriptorProto::FieldDescriptorProto(const FieldDescriptorProto& from)
@@ -3493,7 +3466,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FieldDescriptorProto)
 }
 
-void FieldDescriptorProto::SharedCtor() {
+inline void FieldDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 extendee_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 type_name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -3509,11 +3482,12 @@
 
 FieldDescriptorProto::~FieldDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.FieldDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FieldDescriptorProto::SharedDtor() {
+inline void FieldDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   extendee_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -3916,25 +3890,22 @@
   return total_size;
 }
 
-void FieldDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FieldDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FieldDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FieldDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FieldDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FieldDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FieldDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FieldDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FieldDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void FieldDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FieldDescriptorProto *>(to)->MergeFrom(
+      static_cast<const FieldDescriptorProto &>(from));
 }
 
+
 void FieldDescriptorProto::MergeFrom(const FieldDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FieldDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -3978,13 +3949,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void FieldDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FieldDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FieldDescriptorProto::CopyFrom(const FieldDescriptorProto& from) {
@@ -4064,10 +4029,13 @@
 OneofDescriptorProto::_Internal::options(const OneofDescriptorProto* msg) {
   return *msg->options_;
 }
-OneofDescriptorProto::OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+OneofDescriptorProto::OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.OneofDescriptorProto)
 }
 OneofDescriptorProto::OneofDescriptorProto(const OneofDescriptorProto& from)
@@ -4087,18 +4055,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.OneofDescriptorProto)
 }
 
-void OneofDescriptorProto::SharedCtor() {
+inline void OneofDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 options_ = nullptr;
 }
 
 OneofDescriptorProto::~OneofDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.OneofDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void OneofDescriptorProto::SharedDtor() {
+inline void OneofDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete options_;
@@ -4250,25 +4219,22 @@
   return total_size;
 }
 
-void OneofDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.OneofDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const OneofDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<OneofDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.OneofDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.OneofDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData OneofDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    OneofDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*OneofDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void OneofDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<OneofDescriptorProto *>(to)->MergeFrom(
+      static_cast<const OneofDescriptorProto &>(from));
 }
 
+
 void OneofDescriptorProto::MergeFrom(const OneofDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.OneofDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -4281,13 +4247,7 @@
       _internal_mutable_options()->PROTOBUF_NAMESPACE_ID::OneofOptions::MergeFrom(from._internal_options());
     }
   }
-}
-
-void OneofDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.OneofDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void OneofDescriptorProto::CopyFrom(const OneofDescriptorProto& from) {
@@ -4335,10 +4295,13 @@
   }
 };
 
-EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumDescriptorProto.EnumReservedRange)
 }
 EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(const EnumDescriptorProto_EnumReservedRange& from)
@@ -4351,7 +4314,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumDescriptorProto.EnumReservedRange)
 }
 
-void EnumDescriptorProto_EnumReservedRange::SharedCtor() {
+inline void EnumDescriptorProto_EnumReservedRange::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&start_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&end_) -
@@ -4360,11 +4323,12 @@
 
 EnumDescriptorProto_EnumReservedRange::~EnumDescriptorProto_EnumReservedRange() {
   // @@protoc_insertion_point(destructor:google.protobuf.EnumDescriptorProto.EnumReservedRange)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void EnumDescriptorProto_EnumReservedRange::SharedDtor() {
+inline void EnumDescriptorProto_EnumReservedRange::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -4502,25 +4466,22 @@
   return total_size;
 }
 
-void EnumDescriptorProto_EnumReservedRange::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumDescriptorProto.EnumReservedRange)
-  GOOGLE_DCHECK_NE(&from, this);
-  const EnumDescriptorProto_EnumReservedRange* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<EnumDescriptorProto_EnumReservedRange>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumDescriptorProto.EnumReservedRange)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumDescriptorProto.EnumReservedRange)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData EnumDescriptorProto_EnumReservedRange::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    EnumDescriptorProto_EnumReservedRange::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*EnumDescriptorProto_EnumReservedRange::GetClassData() const { return &_class_data_; }
+
+void EnumDescriptorProto_EnumReservedRange::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<EnumDescriptorProto_EnumReservedRange *>(to)->MergeFrom(
+      static_cast<const EnumDescriptorProto_EnumReservedRange &>(from));
 }
 
+
 void EnumDescriptorProto_EnumReservedRange::MergeFrom(const EnumDescriptorProto_EnumReservedRange& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumDescriptorProto.EnumReservedRange)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -4534,13 +4495,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void EnumDescriptorProto_EnumReservedRange::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumDescriptorProto.EnumReservedRange)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void EnumDescriptorProto_EnumReservedRange::CopyFrom(const EnumDescriptorProto_EnumReservedRange& from) {
@@ -4590,13 +4545,16 @@
 EnumDescriptorProto::_Internal::options(const EnumDescriptorProto* msg) {
   return *msg->options_;
 }
-EnumDescriptorProto::EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+EnumDescriptorProto::EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   value_(arena),
   reserved_range_(arena),
   reserved_name_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumDescriptorProto)
 }
 EnumDescriptorProto::EnumDescriptorProto(const EnumDescriptorProto& from)
@@ -4619,18 +4577,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumDescriptorProto)
 }
 
-void EnumDescriptorProto::SharedCtor() {
+inline void EnumDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 options_ = nullptr;
 }
 
 EnumDescriptorProto::~EnumDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.EnumDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void EnumDescriptorProto::SharedDtor() {
+inline void EnumDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete options_;
@@ -4873,25 +4832,22 @@
   return total_size;
 }
 
-void EnumDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const EnumDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<EnumDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData EnumDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    EnumDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*EnumDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void EnumDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<EnumDescriptorProto *>(to)->MergeFrom(
+      static_cast<const EnumDescriptorProto &>(from));
 }
 
+
 void EnumDescriptorProto::MergeFrom(const EnumDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -4907,13 +4863,7 @@
       _internal_mutable_options()->PROTOBUF_NAMESPACE_ID::EnumOptions::MergeFrom(from._internal_options());
     }
   }
-}
-
-void EnumDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void EnumDescriptorProto::CopyFrom(const EnumDescriptorProto& from) {
@@ -4973,10 +4923,13 @@
 EnumValueDescriptorProto::_Internal::options(const EnumValueDescriptorProto* msg) {
   return *msg->options_;
 }
-EnumValueDescriptorProto::EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+EnumValueDescriptorProto::EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumValueDescriptorProto)
 }
 EnumValueDescriptorProto::EnumValueDescriptorProto(const EnumValueDescriptorProto& from)
@@ -4997,7 +4950,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumValueDescriptorProto)
 }
 
-void EnumValueDescriptorProto::SharedCtor() {
+inline void EnumValueDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&options_) - reinterpret_cast<char*>(this)),
@@ -5007,11 +4960,12 @@
 
 EnumValueDescriptorProto::~EnumValueDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.EnumValueDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void EnumValueDescriptorProto::SharedDtor() {
+inline void EnumValueDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete options_;
@@ -5185,25 +5139,22 @@
   return total_size;
 }
 
-void EnumValueDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumValueDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const EnumValueDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<EnumValueDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumValueDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumValueDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData EnumValueDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    EnumValueDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*EnumValueDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void EnumValueDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<EnumValueDescriptorProto *>(to)->MergeFrom(
+      static_cast<const EnumValueDescriptorProto &>(from));
 }
 
+
 void EnumValueDescriptorProto::MergeFrom(const EnumValueDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumValueDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -5220,13 +5171,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void EnumValueDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumValueDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void EnumValueDescriptorProto::CopyFrom(const EnumValueDescriptorProto& from) {
@@ -5284,11 +5229,14 @@
 ServiceDescriptorProto::_Internal::options(const ServiceDescriptorProto* msg) {
   return *msg->options_;
 }
-ServiceDescriptorProto::ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+ServiceDescriptorProto::ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   method_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ServiceDescriptorProto)
 }
 ServiceDescriptorProto::ServiceDescriptorProto(const ServiceDescriptorProto& from)
@@ -5309,18 +5257,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ServiceDescriptorProto)
 }
 
-void ServiceDescriptorProto::SharedCtor() {
+inline void ServiceDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 options_ = nullptr;
 }
 
 ServiceDescriptorProto::~ServiceDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.ServiceDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void ServiceDescriptorProto::SharedDtor() {
+inline void ServiceDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete options_;
@@ -5500,25 +5449,22 @@
   return total_size;
 }
 
-void ServiceDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ServiceDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const ServiceDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<ServiceDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ServiceDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ServiceDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData ServiceDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    ServiceDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*ServiceDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void ServiceDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<ServiceDescriptorProto *>(to)->MergeFrom(
+      static_cast<const ServiceDescriptorProto &>(from));
 }
 
+
 void ServiceDescriptorProto::MergeFrom(const ServiceDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ServiceDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -5532,13 +5478,7 @@
       _internal_mutable_options()->PROTOBUF_NAMESPACE_ID::ServiceOptions::MergeFrom(from._internal_options());
     }
   }
-}
-
-void ServiceDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ServiceDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void ServiceDescriptorProto::CopyFrom(const ServiceDescriptorProto& from) {
@@ -5605,10 +5545,13 @@
 MethodDescriptorProto::_Internal::options(const MethodDescriptorProto* msg) {
   return *msg->options_;
 }
-MethodDescriptorProto::MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+MethodDescriptorProto::MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.MethodDescriptorProto)
 }
 MethodDescriptorProto::MethodDescriptorProto(const MethodDescriptorProto& from)
@@ -5641,7 +5584,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.MethodDescriptorProto)
 }
 
-void MethodDescriptorProto::SharedCtor() {
+inline void MethodDescriptorProto::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 input_type_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 output_type_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -5653,11 +5596,12 @@
 
 MethodDescriptorProto::~MethodDescriptorProto() {
   // @@protoc_insertion_point(destructor:google.protobuf.MethodDescriptorProto)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void MethodDescriptorProto::SharedDtor() {
+inline void MethodDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   input_type_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -5914,25 +5858,22 @@
   return total_size;
 }
 
-void MethodDescriptorProto::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.MethodDescriptorProto)
-  GOOGLE_DCHECK_NE(&from, this);
-  const MethodDescriptorProto* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<MethodDescriptorProto>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.MethodDescriptorProto)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.MethodDescriptorProto)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData MethodDescriptorProto::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    MethodDescriptorProto::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*MethodDescriptorProto::GetClassData() const { return &_class_data_; }
+
+void MethodDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<MethodDescriptorProto *>(to)->MergeFrom(
+      static_cast<const MethodDescriptorProto &>(from));
 }
 
+
 void MethodDescriptorProto::MergeFrom(const MethodDescriptorProto& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.MethodDescriptorProto)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -5958,13 +5899,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void MethodDescriptorProto::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.MethodDescriptorProto)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void MethodDescriptorProto::CopyFrom(const MethodDescriptorProto& from) {
@@ -6081,12 +6016,15 @@
   }
 };
 
-FileOptions::FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+FileOptions::FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FileOptions)
 }
 FileOptions::FileOptions(const FileOptions& from)
@@ -6151,7 +6089,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FileOptions)
 }
 
-void FileOptions::SharedCtor() {
+inline void FileOptions::SharedCtor() {
 java_package_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 java_outer_classname_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 go_package_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -6172,11 +6110,12 @@
 
 FileOptions::~FileOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.FileOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FileOptions::SharedDtor() {
+inline void FileOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   java_package_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   java_outer_classname_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -6844,26 +6783,22 @@
   return total_size;
 }
 
-void FileOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FileOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FileOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FileOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FileOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FileOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FileOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FileOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FileOptions::GetClassData() const { return &_class_data_; }
+
+void FileOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FileOptions *>(to)->MergeFrom(
+      static_cast<const FileOptions &>(from));
 }
 
+
 void FileOptions::MergeFrom(const FileOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FileOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -6937,13 +6872,8 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void FileOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FileOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FileOptions::CopyFrom(const FileOptions& from) {
@@ -7053,12 +6983,15 @@
   }
 };
 
-MessageOptions::MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+MessageOptions::MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.MessageOptions)
 }
 MessageOptions::MessageOptions(const MessageOptions& from)
@@ -7073,7 +7006,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.MessageOptions)
 }
 
-void MessageOptions::SharedCtor() {
+inline void MessageOptions::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&message_set_wire_format_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&map_entry_) -
@@ -7082,11 +7015,12 @@
 
 MessageOptions::~MessageOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.MessageOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void MessageOptions::SharedDtor() {
+inline void MessageOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -7296,26 +7230,22 @@
   return total_size;
 }
 
-void MessageOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.MessageOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const MessageOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<MessageOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.MessageOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.MessageOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData MessageOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    MessageOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*MessageOptions::GetClassData() const { return &_class_data_; }
+
+void MessageOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<MessageOptions *>(to)->MergeFrom(
+      static_cast<const MessageOptions &>(from));
 }
 
+
 void MessageOptions::MergeFrom(const MessageOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.MessageOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -7336,13 +7266,8 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void MessageOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.MessageOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void MessageOptions::CopyFrom(const MessageOptions& from) {
@@ -7406,12 +7331,15 @@
   }
 };
 
-FieldOptions::FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+FieldOptions::FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FieldOptions)
 }
 FieldOptions::FieldOptions(const FieldOptions& from)
@@ -7426,7 +7354,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FieldOptions)
 }
 
-void FieldOptions::SharedCtor() {
+inline void FieldOptions::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&ctype_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&jstype_) -
@@ -7435,11 +7363,12 @@
 
 FieldOptions::~FieldOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.FieldOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FieldOptions::SharedDtor() {
+inline void FieldOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -7702,26 +7631,22 @@
   return total_size;
 }
 
-void FieldOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FieldOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FieldOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FieldOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FieldOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FieldOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FieldOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FieldOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FieldOptions::GetClassData() const { return &_class_data_; }
+
+void FieldOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FieldOptions *>(to)->MergeFrom(
+      static_cast<const FieldOptions &>(from));
 }
 
+
 void FieldOptions::MergeFrom(const FieldOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FieldOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -7748,13 +7673,8 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void FieldOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FieldOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FieldOptions::CopyFrom(const FieldOptions& from) {
@@ -7799,12 +7719,15 @@
  public:
 };
 
-OneofOptions::OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+OneofOptions::OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.OneofOptions)
 }
 OneofOptions::OneofOptions(const OneofOptions& from)
@@ -7815,16 +7738,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.OneofOptions)
 }
 
-void OneofOptions::SharedCtor() {
+inline void OneofOptions::SharedCtor() {
 }
 
 OneofOptions::~OneofOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.OneofOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void OneofOptions::SharedDtor() {
+inline void OneofOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -7948,37 +7872,28 @@
   return total_size;
 }
 
-void OneofOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.OneofOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const OneofOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<OneofOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.OneofOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.OneofOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData OneofOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    OneofOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*OneofOptions::GetClassData() const { return &_class_data_; }
+
+void OneofOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<OneofOptions *>(to)->MergeFrom(
+      static_cast<const OneofOptions &>(from));
 }
 
+
 void OneofOptions::MergeFrom(const OneofOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.OneofOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
-}
-
-void OneofOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.OneofOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void OneofOptions::CopyFrom(const OneofOptions& from) {
@@ -8023,12 +7938,15 @@
   }
 };
 
-EnumOptions::EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+EnumOptions::EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumOptions)
 }
 EnumOptions::EnumOptions(const EnumOptions& from)
@@ -8043,7 +7961,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumOptions)
 }
 
-void EnumOptions::SharedCtor() {
+inline void EnumOptions::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&allow_alias_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&deprecated_) -
@@ -8052,11 +7970,12 @@
 
 EnumOptions::~EnumOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.EnumOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void EnumOptions::SharedDtor() {
+inline void EnumOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -8228,26 +8147,22 @@
   return total_size;
 }
 
-void EnumOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const EnumOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<EnumOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData EnumOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    EnumOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*EnumOptions::GetClassData() const { return &_class_data_; }
+
+void EnumOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<EnumOptions *>(to)->MergeFrom(
+      static_cast<const EnumOptions &>(from));
 }
 
+
 void EnumOptions::MergeFrom(const EnumOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -8262,13 +8177,8 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void EnumOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void EnumOptions::CopyFrom(const EnumOptions& from) {
@@ -8317,12 +8227,15 @@
   }
 };
 
-EnumValueOptions::EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+EnumValueOptions::EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumValueOptions)
 }
 EnumValueOptions::EnumValueOptions(const EnumValueOptions& from)
@@ -8335,17 +8248,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumValueOptions)
 }
 
-void EnumValueOptions::SharedCtor() {
+inline void EnumValueOptions::SharedCtor() {
 deprecated_ = false;
 }
 
 EnumValueOptions::~EnumValueOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.EnumValueOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void EnumValueOptions::SharedDtor() {
+inline void EnumValueOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -8494,26 +8408,22 @@
   return total_size;
 }
 
-void EnumValueOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumValueOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const EnumValueOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<EnumValueOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumValueOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumValueOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData EnumValueOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    EnumValueOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*EnumValueOptions::GetClassData() const { return &_class_data_; }
+
+void EnumValueOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<EnumValueOptions *>(to)->MergeFrom(
+      static_cast<const EnumValueOptions &>(from));
 }
 
+
 void EnumValueOptions::MergeFrom(const EnumValueOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumValueOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -8521,13 +8431,8 @@
   if (from._internal_has_deprecated()) {
     _internal_set_deprecated(from._internal_deprecated());
   }
-}
-
-void EnumValueOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumValueOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void EnumValueOptions::CopyFrom(const EnumValueOptions& from) {
@@ -8571,12 +8476,15 @@
   }
 };
 
-ServiceOptions::ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+ServiceOptions::ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ServiceOptions)
 }
 ServiceOptions::ServiceOptions(const ServiceOptions& from)
@@ -8589,17 +8497,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ServiceOptions)
 }
 
-void ServiceOptions::SharedCtor() {
+inline void ServiceOptions::SharedCtor() {
 deprecated_ = false;
 }
 
 ServiceOptions::~ServiceOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.ServiceOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void ServiceOptions::SharedDtor() {
+inline void ServiceOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -8748,26 +8657,22 @@
   return total_size;
 }
 
-void ServiceOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ServiceOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const ServiceOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<ServiceOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ServiceOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ServiceOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData ServiceOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    ServiceOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*ServiceOptions::GetClassData() const { return &_class_data_; }
+
+void ServiceOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<ServiceOptions *>(to)->MergeFrom(
+      static_cast<const ServiceOptions &>(from));
 }
 
+
 void ServiceOptions::MergeFrom(const ServiceOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ServiceOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -8775,13 +8680,8 @@
   if (from._internal_has_deprecated()) {
     _internal_set_deprecated(from._internal_deprecated());
   }
-}
-
-void ServiceOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ServiceOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void ServiceOptions::CopyFrom(const ServiceOptions& from) {
@@ -8828,12 +8728,15 @@
   }
 };
 
-MethodOptions::MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+MethodOptions::MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   _extensions_(arena),
   uninterpreted_option_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.MethodOptions)
 }
 MethodOptions::MethodOptions(const MethodOptions& from)
@@ -8848,7 +8751,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.MethodOptions)
 }
 
-void MethodOptions::SharedCtor() {
+inline void MethodOptions::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&deprecated_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&idempotency_level_) -
@@ -8857,11 +8760,12 @@
 
 MethodOptions::~MethodOptions() {
   // @@protoc_insertion_point(destructor:google.protobuf.MethodOptions)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void MethodOptions::SharedDtor() {
+inline void MethodOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -9042,26 +8946,22 @@
   return total_size;
 }
 
-void MethodOptions::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.MethodOptions)
-  GOOGLE_DCHECK_NE(&from, this);
-  const MethodOptions* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<MethodOptions>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.MethodOptions)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.MethodOptions)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData MethodOptions::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    MethodOptions::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*MethodOptions::GetClassData() const { return &_class_data_; }
+
+void MethodOptions::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<MethodOptions *>(to)->MergeFrom(
+      static_cast<const MethodOptions &>(from));
 }
 
+
 void MethodOptions::MergeFrom(const MethodOptions& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.MethodOptions)
   GOOGLE_DCHECK_NE(&from, this);
-  _extensions_.MergeFrom(from._extensions_);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -9076,13 +8976,8 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void MethodOptions::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.MethodOptions)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _extensions_.MergeFrom(from._extensions_);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void MethodOptions::CopyFrom(const MethodOptions& from) {
@@ -9137,10 +9032,13 @@
   }
 };
 
-UninterpretedOption_NamePart::UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+UninterpretedOption_NamePart::UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.UninterpretedOption.NamePart)
 }
 UninterpretedOption_NamePart::UninterpretedOption_NamePart(const UninterpretedOption_NamePart& from)
@@ -9156,18 +9054,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.UninterpretedOption.NamePart)
 }
 
-void UninterpretedOption_NamePart::SharedCtor() {
+inline void UninterpretedOption_NamePart::SharedCtor() {
 name_part_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 is_extension_ = false;
 }
 
 UninterpretedOption_NamePart::~UninterpretedOption_NamePart() {
   // @@protoc_insertion_point(destructor:google.protobuf.UninterpretedOption.NamePart)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void UninterpretedOption_NamePart::SharedDtor() {
+inline void UninterpretedOption_NamePart::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_part_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -9325,25 +9224,22 @@
   return total_size;
 }
 
-void UninterpretedOption_NamePart::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UninterpretedOption.NamePart)
-  GOOGLE_DCHECK_NE(&from, this);
-  const UninterpretedOption_NamePart* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<UninterpretedOption_NamePart>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UninterpretedOption.NamePart)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UninterpretedOption.NamePart)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData UninterpretedOption_NamePart::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    UninterpretedOption_NamePart::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*UninterpretedOption_NamePart::GetClassData() const { return &_class_data_; }
+
+void UninterpretedOption_NamePart::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<UninterpretedOption_NamePart *>(to)->MergeFrom(
+      static_cast<const UninterpretedOption_NamePart &>(from));
 }
 
+
 void UninterpretedOption_NamePart::MergeFrom(const UninterpretedOption_NamePart& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UninterpretedOption.NamePart)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -9357,13 +9253,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void UninterpretedOption_NamePart::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UninterpretedOption.NamePart)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void UninterpretedOption_NamePart::CopyFrom(const UninterpretedOption_NamePart& from) {
@@ -9421,11 +9311,14 @@
   }
 };
 
-UninterpretedOption::UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+UninterpretedOption::UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   name_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.UninterpretedOption)
 }
 UninterpretedOption::UninterpretedOption(const UninterpretedOption& from)
@@ -9454,7 +9347,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.UninterpretedOption)
 }
 
-void UninterpretedOption::SharedCtor() {
+inline void UninterpretedOption::SharedCtor() {
 identifier_value_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 string_value_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 aggregate_value_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -9466,11 +9359,12 @@
 
 UninterpretedOption::~UninterpretedOption() {
   // @@protoc_insertion_point(destructor:google.protobuf.UninterpretedOption)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void UninterpretedOption::SharedDtor() {
+inline void UninterpretedOption::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   identifier_value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   string_value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -9746,25 +9640,22 @@
   return total_size;
 }
 
-void UninterpretedOption::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UninterpretedOption)
-  GOOGLE_DCHECK_NE(&from, this);
-  const UninterpretedOption* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<UninterpretedOption>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UninterpretedOption)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UninterpretedOption)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData UninterpretedOption::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    UninterpretedOption::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*UninterpretedOption::GetClassData() const { return &_class_data_; }
+
+void UninterpretedOption::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<UninterpretedOption *>(to)->MergeFrom(
+      static_cast<const UninterpretedOption &>(from));
 }
 
+
 void UninterpretedOption::MergeFrom(const UninterpretedOption& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UninterpretedOption)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -9791,13 +9682,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void UninterpretedOption::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UninterpretedOption)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void UninterpretedOption::CopyFrom(const UninterpretedOption& from) {
@@ -9859,13 +9744,16 @@
   }
 };
 
-SourceCodeInfo_Location::SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+SourceCodeInfo_Location::SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   path_(arena),
   span_(arena),
   leading_detached_comments_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.SourceCodeInfo.Location)
 }
 SourceCodeInfo_Location::SourceCodeInfo_Location(const SourceCodeInfo_Location& from)
@@ -9888,18 +9776,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.SourceCodeInfo.Location)
 }
 
-void SourceCodeInfo_Location::SharedCtor() {
+inline void SourceCodeInfo_Location::SharedCtor() {
 leading_comments_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 trailing_comments_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
 
 SourceCodeInfo_Location::~SourceCodeInfo_Location() {
   // @@protoc_insertion_point(destructor:google.protobuf.SourceCodeInfo.Location)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void SourceCodeInfo_Location::SharedDtor() {
+inline void SourceCodeInfo_Location::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   leading_comments_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   trailing_comments_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -10161,25 +10050,22 @@
   return total_size;
 }
 
-void SourceCodeInfo_Location::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.SourceCodeInfo.Location)
-  GOOGLE_DCHECK_NE(&from, this);
-  const SourceCodeInfo_Location* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<SourceCodeInfo_Location>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.SourceCodeInfo.Location)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.SourceCodeInfo.Location)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData SourceCodeInfo_Location::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    SourceCodeInfo_Location::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*SourceCodeInfo_Location::GetClassData() const { return &_class_data_; }
+
+void SourceCodeInfo_Location::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<SourceCodeInfo_Location *>(to)->MergeFrom(
+      static_cast<const SourceCodeInfo_Location &>(from));
 }
 
+
 void SourceCodeInfo_Location::MergeFrom(const SourceCodeInfo_Location& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.SourceCodeInfo.Location)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -10195,13 +10081,7 @@
       _internal_set_trailing_comments(from._internal_trailing_comments());
     }
   }
-}
-
-void SourceCodeInfo_Location::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.SourceCodeInfo.Location)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void SourceCodeInfo_Location::CopyFrom(const SourceCodeInfo_Location& from) {
@@ -10246,11 +10126,14 @@
  public:
 };
 
-SourceCodeInfo::SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+SourceCodeInfo::SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   location_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.SourceCodeInfo)
 }
 SourceCodeInfo::SourceCodeInfo(const SourceCodeInfo& from)
@@ -10260,16 +10143,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.SourceCodeInfo)
 }
 
-void SourceCodeInfo::SharedCtor() {
+inline void SourceCodeInfo::SharedCtor() {
 }
 
 SourceCodeInfo::~SourceCodeInfo() {
   // @@protoc_insertion_point(destructor:google.protobuf.SourceCodeInfo)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void SourceCodeInfo::SharedDtor() {
+inline void SourceCodeInfo::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -10380,36 +10264,27 @@
   return total_size;
 }
 
-void SourceCodeInfo::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.SourceCodeInfo)
-  GOOGLE_DCHECK_NE(&from, this);
-  const SourceCodeInfo* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<SourceCodeInfo>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.SourceCodeInfo)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.SourceCodeInfo)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData SourceCodeInfo::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    SourceCodeInfo::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*SourceCodeInfo::GetClassData() const { return &_class_data_; }
+
+void SourceCodeInfo::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<SourceCodeInfo *>(to)->MergeFrom(
+      static_cast<const SourceCodeInfo &>(from));
 }
 
+
 void SourceCodeInfo::MergeFrom(const SourceCodeInfo& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.SourceCodeInfo)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   location_.MergeFrom(from.location_);
-}
-
-void SourceCodeInfo::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.SourceCodeInfo)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void SourceCodeInfo::CopyFrom(const SourceCodeInfo& from) {
@@ -10451,11 +10326,14 @@
   }
 };
 
-GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   path_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.GeneratedCodeInfo.Annotation)
 }
 GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(const GeneratedCodeInfo_Annotation& from)
@@ -10474,7 +10352,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.GeneratedCodeInfo.Annotation)
 }
 
-void GeneratedCodeInfo_Annotation::SharedCtor() {
+inline void GeneratedCodeInfo_Annotation::SharedCtor() {
 source_file_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&begin_) - reinterpret_cast<char*>(this)),
@@ -10484,11 +10362,12 @@
 
 GeneratedCodeInfo_Annotation::~GeneratedCodeInfo_Annotation() {
   // @@protoc_insertion_point(destructor:google.protobuf.GeneratedCodeInfo.Annotation)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void GeneratedCodeInfo_Annotation::SharedDtor() {
+inline void GeneratedCodeInfo_Annotation::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   source_file_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -10693,25 +10572,22 @@
   return total_size;
 }
 
-void GeneratedCodeInfo_Annotation::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
-  GOOGLE_DCHECK_NE(&from, this);
-  const GeneratedCodeInfo_Annotation* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<GeneratedCodeInfo_Annotation>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.GeneratedCodeInfo.Annotation)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.GeneratedCodeInfo.Annotation)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData GeneratedCodeInfo_Annotation::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    GeneratedCodeInfo_Annotation::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GeneratedCodeInfo_Annotation::GetClassData() const { return &_class_data_; }
+
+void GeneratedCodeInfo_Annotation::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<GeneratedCodeInfo_Annotation *>(to)->MergeFrom(
+      static_cast<const GeneratedCodeInfo_Annotation &>(from));
 }
 
+
 void GeneratedCodeInfo_Annotation::MergeFrom(const GeneratedCodeInfo_Annotation& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -10729,13 +10605,7 @@
     }
     _has_bits_[0] |= cached_has_bits;
   }
-}
-
-void GeneratedCodeInfo_Annotation::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void GeneratedCodeInfo_Annotation::CopyFrom(const GeneratedCodeInfo_Annotation& from) {
@@ -10779,11 +10649,14 @@
  public:
 };
 
-GeneratedCodeInfo::GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+GeneratedCodeInfo::GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   annotation_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.GeneratedCodeInfo)
 }
 GeneratedCodeInfo::GeneratedCodeInfo(const GeneratedCodeInfo& from)
@@ -10793,16 +10666,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.GeneratedCodeInfo)
 }
 
-void GeneratedCodeInfo::SharedCtor() {
+inline void GeneratedCodeInfo::SharedCtor() {
 }
 
 GeneratedCodeInfo::~GeneratedCodeInfo() {
   // @@protoc_insertion_point(destructor:google.protobuf.GeneratedCodeInfo)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void GeneratedCodeInfo::SharedDtor() {
+inline void GeneratedCodeInfo::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -10913,36 +10787,27 @@
   return total_size;
 }
 
-void GeneratedCodeInfo::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.GeneratedCodeInfo)
-  GOOGLE_DCHECK_NE(&from, this);
-  const GeneratedCodeInfo* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<GeneratedCodeInfo>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.GeneratedCodeInfo)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.GeneratedCodeInfo)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData GeneratedCodeInfo::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    GeneratedCodeInfo::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GeneratedCodeInfo::GetClassData() const { return &_class_data_; }
+
+void GeneratedCodeInfo::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<GeneratedCodeInfo *>(to)->MergeFrom(
+      static_cast<const GeneratedCodeInfo &>(from));
 }
 
+
 void GeneratedCodeInfo::MergeFrom(const GeneratedCodeInfo& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.GeneratedCodeInfo)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   annotation_.MergeFrom(from.annotation_);
-}
-
-void GeneratedCodeInfo::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.GeneratedCodeInfo)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void GeneratedCodeInfo::CopyFrom(const GeneratedCodeInfo& from) {
diff --git a/src/google/protobuf/descriptor.pb.h b/src/google/protobuf/descriptor.pb.h
index ad1ce4c..d86c843 100644
--- a/src/google/protobuf/descriptor.pb.h
+++ b/src/google/protobuf/descriptor.pb.h
@@ -408,10 +408,13 @@
   FileDescriptorSet* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FileDescriptorSet>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FileDescriptorSet& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FileDescriptorSet& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -431,12 +434,16 @@
     return "google.protobuf.FileDescriptorSet";
   }
   protected:
-  explicit FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -556,10 +563,13 @@
   FileDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FileDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FileDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FileDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -579,12 +589,16 @@
     return "google.protobuf.FileDescriptorProto";
   }
   protected:
-  explicit FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -755,7 +769,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -773,7 +787,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_package(ArgT0&& arg0, ArgT... args);
   std::string* mutable_package();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_package();
+  PROTOBUF_MUST_USE_RESULT std::string* release_package();
   void set_allocated_package(std::string* package);
   private:
   const std::string& _internal_package() const;
@@ -791,7 +805,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_syntax(ArgT0&& arg0, ArgT... args);
   std::string* mutable_syntax();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_syntax();
+  PROTOBUF_MUST_USE_RESULT std::string* release_syntax();
   void set_allocated_syntax(std::string* syntax);
   private:
   const std::string& _internal_syntax() const;
@@ -806,7 +820,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::FileOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::FileOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::FileOptions* release_options();
   PROTOBUF_NAMESPACE_ID::FileOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::FileOptions* options);
   private:
@@ -824,7 +838,7 @@
   public:
   void clear_source_code_info();
   const PROTOBUF_NAMESPACE_ID::SourceCodeInfo& source_code_info() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceCodeInfo* release_source_code_info();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceCodeInfo* release_source_code_info();
   PROTOBUF_NAMESPACE_ID::SourceCodeInfo* mutable_source_code_info();
   void set_allocated_source_code_info(PROTOBUF_NAMESPACE_ID::SourceCodeInfo* source_code_info);
   private:
@@ -939,10 +953,13 @@
   DescriptorProto_ExtensionRange* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<DescriptorProto_ExtensionRange>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const DescriptorProto_ExtensionRange& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const DescriptorProto_ExtensionRange& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -962,12 +979,16 @@
     return "google.protobuf.DescriptorProto.ExtensionRange";
   }
   protected:
-  explicit DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -986,7 +1007,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* release_options();
   PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* options);
   private:
@@ -1118,10 +1139,13 @@
   DescriptorProto_ReservedRange* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<DescriptorProto_ReservedRange>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const DescriptorProto_ReservedRange& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const DescriptorProto_ReservedRange& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1141,12 +1165,16 @@
     return "google.protobuf.DescriptorProto.ReservedRange";
   }
   protected:
-  explicit DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1277,10 +1305,13 @@
   DescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<DescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const DescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const DescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1300,12 +1331,16 @@
     return "google.protobuf.DescriptorProto";
   }
   protected:
-  explicit DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1487,7 +1522,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -1502,7 +1537,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::MessageOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::MessageOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::MessageOptions* release_options();
   PROTOBUF_NAMESPACE_ID::MessageOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::MessageOptions* options);
   private:
@@ -1615,10 +1650,13 @@
   ExtensionRangeOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<ExtensionRangeOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const ExtensionRangeOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const ExtensionRangeOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1638,12 +1676,16 @@
     return "google.protobuf.ExtensionRangeOptions";
   }
   protected:
-  explicit ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1766,10 +1808,13 @@
   FieldDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FieldDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FieldDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FieldDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1789,12 +1834,16 @@
     return "google.protobuf.FieldDescriptorProto";
   }
   protected:
-  explicit FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1918,7 +1967,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -1936,7 +1985,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_extendee(ArgT0&& arg0, ArgT... args);
   std::string* mutable_extendee();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_extendee();
+  PROTOBUF_MUST_USE_RESULT std::string* release_extendee();
   void set_allocated_extendee(std::string* extendee);
   private:
   const std::string& _internal_extendee() const;
@@ -1954,7 +2003,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_type_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_type_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_type_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_type_name();
   void set_allocated_type_name(std::string* type_name);
   private:
   const std::string& _internal_type_name() const;
@@ -1972,7 +2021,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_default_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_default_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_default_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_default_value();
   void set_allocated_default_value(std::string* default_value);
   private:
   const std::string& _internal_default_value() const;
@@ -1990,7 +2039,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_json_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_json_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_json_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_json_name();
   void set_allocated_json_name(std::string* json_name);
   private:
   const std::string& _internal_json_name() const;
@@ -2005,7 +2054,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::FieldOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::FieldOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::FieldOptions* release_options();
   PROTOBUF_NAMESPACE_ID::FieldOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::FieldOptions* options);
   private:
@@ -2184,10 +2233,13 @@
   OneofDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<OneofDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const OneofDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const OneofDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -2207,12 +2259,16 @@
     return "google.protobuf.OneofDescriptorProto";
   }
   protected:
-  explicit OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -2233,7 +2289,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -2248,7 +2304,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::OneofOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::OneofOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::OneofOptions* release_options();
   PROTOBUF_NAMESPACE_ID::OneofOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::OneofOptions* options);
   private:
@@ -2353,10 +2409,13 @@
   EnumDescriptorProto_EnumReservedRange* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<EnumDescriptorProto_EnumReservedRange>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const EnumDescriptorProto_EnumReservedRange& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const EnumDescriptorProto_EnumReservedRange& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -2376,12 +2435,16 @@
     return "google.protobuf.EnumDescriptorProto.EnumReservedRange";
   }
   protected:
-  explicit EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -2512,10 +2575,13 @@
   EnumDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<EnumDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const EnumDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const EnumDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -2535,12 +2601,16 @@
     return "google.protobuf.EnumDescriptorProto";
   }
   protected:
-  explicit EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -2626,7 +2696,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -2641,7 +2711,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::EnumOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::EnumOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::EnumOptions* release_options();
   PROTOBUF_NAMESPACE_ID::EnumOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::EnumOptions* options);
   private:
@@ -2749,10 +2819,13 @@
   EnumValueDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<EnumValueDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const EnumValueDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const EnumValueDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -2772,12 +2845,16 @@
     return "google.protobuf.EnumValueDescriptorProto";
   }
   protected:
-  explicit EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -2799,7 +2876,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -2814,7 +2891,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::EnumValueOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::EnumValueOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::EnumValueOptions* release_options();
   PROTOBUF_NAMESPACE_ID::EnumValueOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::EnumValueOptions* options);
   private:
@@ -2933,10 +3010,13 @@
   ServiceDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<ServiceDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const ServiceDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const ServiceDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -2956,12 +3036,16 @@
     return "google.protobuf.ServiceDescriptorProto";
   }
   protected:
-  explicit ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -3001,7 +3085,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -3016,7 +3100,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::ServiceOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::ServiceOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::ServiceOptions* release_options();
   PROTOBUF_NAMESPACE_ID::ServiceOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::ServiceOptions* options);
   private:
@@ -3122,10 +3206,13 @@
   MethodDescriptorProto* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<MethodDescriptorProto>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const MethodDescriptorProto& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const MethodDescriptorProto& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -3145,12 +3232,16 @@
     return "google.protobuf.MethodDescriptorProto";
   }
   protected:
-  explicit MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -3175,7 +3266,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -3193,7 +3284,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_input_type(ArgT0&& arg0, ArgT... args);
   std::string* mutable_input_type();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_input_type();
+  PROTOBUF_MUST_USE_RESULT std::string* release_input_type();
   void set_allocated_input_type(std::string* input_type);
   private:
   const std::string& _internal_input_type() const;
@@ -3211,7 +3302,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_output_type(ArgT0&& arg0, ArgT... args);
   std::string* mutable_output_type();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_output_type();
+  PROTOBUF_MUST_USE_RESULT std::string* release_output_type();
   void set_allocated_output_type(std::string* output_type);
   private:
   const std::string& _internal_output_type() const;
@@ -3226,7 +3317,7 @@
   public:
   void clear_options();
   const PROTOBUF_NAMESPACE_ID::MethodOptions& options() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::MethodOptions* release_options();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::MethodOptions* release_options();
   PROTOBUF_NAMESPACE_ID::MethodOptions* mutable_options();
   void set_allocated_options(PROTOBUF_NAMESPACE_ID::MethodOptions* options);
   private:
@@ -3361,10 +3452,13 @@
   FileOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FileOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FileOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FileOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -3384,12 +3478,16 @@
     return "google.protobuf.FileOptions";
   }
   protected:
-  explicit FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -3479,7 +3577,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_java_package(ArgT0&& arg0, ArgT... args);
   std::string* mutable_java_package();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_java_package();
+  PROTOBUF_MUST_USE_RESULT std::string* release_java_package();
   void set_allocated_java_package(std::string* java_package);
   private:
   const std::string& _internal_java_package() const;
@@ -3497,7 +3595,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_java_outer_classname(ArgT0&& arg0, ArgT... args);
   std::string* mutable_java_outer_classname();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_java_outer_classname();
+  PROTOBUF_MUST_USE_RESULT std::string* release_java_outer_classname();
   void set_allocated_java_outer_classname(std::string* java_outer_classname);
   private:
   const std::string& _internal_java_outer_classname() const;
@@ -3515,7 +3613,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_go_package(ArgT0&& arg0, ArgT... args);
   std::string* mutable_go_package();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_go_package();
+  PROTOBUF_MUST_USE_RESULT std::string* release_go_package();
   void set_allocated_go_package(std::string* go_package);
   private:
   const std::string& _internal_go_package() const;
@@ -3533,7 +3631,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_objc_class_prefix(ArgT0&& arg0, ArgT... args);
   std::string* mutable_objc_class_prefix();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_objc_class_prefix();
+  PROTOBUF_MUST_USE_RESULT std::string* release_objc_class_prefix();
   void set_allocated_objc_class_prefix(std::string* objc_class_prefix);
   private:
   const std::string& _internal_objc_class_prefix() const;
@@ -3551,7 +3649,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_csharp_namespace(ArgT0&& arg0, ArgT... args);
   std::string* mutable_csharp_namespace();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_csharp_namespace();
+  PROTOBUF_MUST_USE_RESULT std::string* release_csharp_namespace();
   void set_allocated_csharp_namespace(std::string* csharp_namespace);
   private:
   const std::string& _internal_csharp_namespace() const;
@@ -3569,7 +3667,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_swift_prefix(ArgT0&& arg0, ArgT... args);
   std::string* mutable_swift_prefix();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_swift_prefix();
+  PROTOBUF_MUST_USE_RESULT std::string* release_swift_prefix();
   void set_allocated_swift_prefix(std::string* swift_prefix);
   private:
   const std::string& _internal_swift_prefix() const;
@@ -3587,7 +3685,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_php_class_prefix(ArgT0&& arg0, ArgT... args);
   std::string* mutable_php_class_prefix();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_php_class_prefix();
+  PROTOBUF_MUST_USE_RESULT std::string* release_php_class_prefix();
   void set_allocated_php_class_prefix(std::string* php_class_prefix);
   private:
   const std::string& _internal_php_class_prefix() const;
@@ -3605,7 +3703,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_php_namespace(ArgT0&& arg0, ArgT... args);
   std::string* mutable_php_namespace();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_php_namespace();
+  PROTOBUF_MUST_USE_RESULT std::string* release_php_namespace();
   void set_allocated_php_namespace(std::string* php_namespace);
   private:
   const std::string& _internal_php_namespace() const;
@@ -3623,7 +3721,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_php_metadata_namespace(ArgT0&& arg0, ArgT... args);
   std::string* mutable_php_metadata_namespace();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_php_metadata_namespace();
+  PROTOBUF_MUST_USE_RESULT std::string* release_php_metadata_namespace();
   void set_allocated_php_metadata_namespace(std::string* php_metadata_namespace);
   private:
   const std::string& _internal_php_metadata_namespace() const;
@@ -3641,7 +3739,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_ruby_package(ArgT0&& arg0, ArgT... args);
   std::string* mutable_ruby_package();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_ruby_package();
+  PROTOBUF_MUST_USE_RESULT std::string* release_ruby_package();
   void set_allocated_ruby_package(std::string* ruby_package);
   private:
   const std::string& _internal_ruby_package() const;
@@ -3895,10 +3993,13 @@
   MessageOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<MessageOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const MessageOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const MessageOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -3918,12 +4019,16 @@
     return "google.protobuf.MessageOptions";
   }
   protected:
-  explicit MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -4107,10 +4212,13 @@
   FieldOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FieldOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FieldOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FieldOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -4130,12 +4238,16 @@
     return "google.protobuf.FieldOptions";
   }
   protected:
-  explicit FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -4413,10 +4525,13 @@
   OneofOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<OneofOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const OneofOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const OneofOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -4436,12 +4551,16 @@
     return "google.protobuf.OneofOptions";
   }
   protected:
-  explicit OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -4564,10 +4683,13 @@
   EnumOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<EnumOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const EnumOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const EnumOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -4587,12 +4709,16 @@
     return "google.protobuf.EnumOptions";
   }
   protected:
-  explicit EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -4746,10 +4872,13 @@
   EnumValueOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<EnumValueOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const EnumValueOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const EnumValueOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -4769,12 +4898,16 @@
     return "google.protobuf.EnumValueOptions";
   }
   protected:
-  explicit EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -4913,10 +5046,13 @@
   ServiceOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<ServiceOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const ServiceOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const ServiceOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -4936,12 +5072,16 @@
     return "google.protobuf.ServiceOptions";
   }
   protected:
-  explicit ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -5080,10 +5220,13 @@
   MethodOptions* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<MethodOptions>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const MethodOptions& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const MethodOptions& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -5103,12 +5246,16 @@
     return "google.protobuf.MethodOptions";
   }
   protected:
-  explicit MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -5294,10 +5441,13 @@
   UninterpretedOption_NamePart* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<UninterpretedOption_NamePart>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const UninterpretedOption_NamePart& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const UninterpretedOption_NamePart& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -5317,12 +5467,16 @@
     return "google.protobuf.UninterpretedOption.NamePart";
   }
   protected:
-  explicit UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -5343,7 +5497,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name_part(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name_part();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name_part();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name_part();
   void set_allocated_name_part(std::string* name_part);
   private:
   const std::string& _internal_name_part() const;
@@ -5461,10 +5615,13 @@
   UninterpretedOption* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<UninterpretedOption>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const UninterpretedOption& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const UninterpretedOption& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -5484,12 +5641,16 @@
     return "google.protobuf.UninterpretedOption";
   }
   protected:
-  explicit UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -5535,7 +5696,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_identifier_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_identifier_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_identifier_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_identifier_value();
   void set_allocated_identifier_value(std::string* identifier_value);
   private:
   const std::string& _internal_identifier_value() const;
@@ -5553,7 +5714,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_string_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_string_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_string_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_string_value();
   void set_allocated_string_value(std::string* string_value);
   private:
   const std::string& _internal_string_value() const;
@@ -5571,7 +5732,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_aggregate_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_aggregate_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_aggregate_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_aggregate_value();
   void set_allocated_aggregate_value(std::string* aggregate_value);
   private:
   const std::string& _internal_aggregate_value() const;
@@ -5717,10 +5878,13 @@
   SourceCodeInfo_Location* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<SourceCodeInfo_Location>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const SourceCodeInfo_Location& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const SourceCodeInfo_Location& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -5740,12 +5904,16 @@
     return "google.protobuf.SourceCodeInfo.Location";
   }
   protected:
-  explicit SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -5837,7 +6005,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_leading_comments(ArgT0&& arg0, ArgT... args);
   std::string* mutable_leading_comments();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_leading_comments();
+  PROTOBUF_MUST_USE_RESULT std::string* release_leading_comments();
   void set_allocated_leading_comments(std::string* leading_comments);
   private:
   const std::string& _internal_leading_comments() const;
@@ -5855,7 +6023,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_trailing_comments(ArgT0&& arg0, ArgT... args);
   std::string* mutable_trailing_comments();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_trailing_comments();
+  PROTOBUF_MUST_USE_RESULT std::string* release_trailing_comments();
   void set_allocated_trailing_comments(std::string* trailing_comments);
   private:
   const std::string& _internal_trailing_comments() const;
@@ -5962,10 +6130,13 @@
   SourceCodeInfo* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<SourceCodeInfo>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const SourceCodeInfo& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const SourceCodeInfo& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -5985,12 +6156,16 @@
     return "google.protobuf.SourceCodeInfo";
   }
   protected:
-  explicit SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -6112,10 +6287,13 @@
   GeneratedCodeInfo_Annotation* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<GeneratedCodeInfo_Annotation>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const GeneratedCodeInfo_Annotation& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const GeneratedCodeInfo_Annotation& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -6135,12 +6313,16 @@
     return "google.protobuf.GeneratedCodeInfo.Annotation";
   }
   protected:
-  explicit GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -6185,7 +6367,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_source_file(ArgT0&& arg0, ArgT... args);
   std::string* mutable_source_file();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_source_file();
+  PROTOBUF_MUST_USE_RESULT std::string* release_source_file();
   void set_allocated_source_file(std::string* source_file);
   private:
   const std::string& _internal_source_file() const;
@@ -6316,10 +6498,13 @@
   GeneratedCodeInfo* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<GeneratedCodeInfo>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const GeneratedCodeInfo& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const GeneratedCodeInfo& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -6339,12 +6524,16 @@
     return "google.protobuf.GeneratedCodeInfo";
   }
   protected:
-  explicit GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -6426,8 +6615,9 @@
   return file_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::FileDescriptorProto* FileDescriptorSet::add_file() {
+  PROTOBUF_NAMESPACE_ID::FileDescriptorProto* _add = _internal_add_file();
   // @@protoc_insertion_point(field_add:google.protobuf.FileDescriptorSet.file)
-  return _internal_add_file();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::FileDescriptorProto >&
 FileDescriptorSet::file() const {
@@ -6463,8 +6653,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.name)
 }
 inline std::string* FileDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& FileDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -6520,8 +6711,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.package)
 }
 inline std::string* FileDescriptorProto::mutable_package() {
+  std::string* _s = _internal_mutable_package();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileDescriptorProto.package)
-  return _internal_mutable_package();
+  return _s;
 }
 inline const std::string& FileDescriptorProto::_internal_package() const {
   return package_.Get();
@@ -6564,8 +6756,9 @@
   dependency_.Clear();
 }
 inline std::string* FileDescriptorProto::add_dependency() {
+  std::string* _s = _internal_add_dependency();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.FileDescriptorProto.dependency)
-  return _internal_add_dependency();
+  return _s;
 }
 inline const std::string& FileDescriptorProto::_internal_dependency(int index) const {
   return dependency_.Get(index);
@@ -6579,12 +6772,12 @@
   return dependency_.Mutable(index);
 }
 inline void FileDescriptorProto::set_dependency(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.dependency)
   dependency_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.dependency)
 }
 inline void FileDescriptorProto::set_dependency(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.dependency)
   dependency_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.dependency)
 }
 inline void FileDescriptorProto::set_dependency(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
@@ -6751,8 +6944,9 @@
   return message_type_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::DescriptorProto* FileDescriptorProto::add_message_type() {
+  PROTOBUF_NAMESPACE_ID::DescriptorProto* _add = _internal_add_message_type();
   // @@protoc_insertion_point(field_add:google.protobuf.FileDescriptorProto.message_type)
-  return _internal_add_message_type();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::DescriptorProto >&
 FileDescriptorProto::message_type() const {
@@ -6790,8 +6984,9 @@
   return enum_type_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::EnumDescriptorProto* FileDescriptorProto::add_enum_type() {
+  PROTOBUF_NAMESPACE_ID::EnumDescriptorProto* _add = _internal_add_enum_type();
   // @@protoc_insertion_point(field_add:google.protobuf.FileDescriptorProto.enum_type)
-  return _internal_add_enum_type();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::EnumDescriptorProto >&
 FileDescriptorProto::enum_type() const {
@@ -6829,8 +7024,9 @@
   return service_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::ServiceDescriptorProto* FileDescriptorProto::add_service() {
+  PROTOBUF_NAMESPACE_ID::ServiceDescriptorProto* _add = _internal_add_service();
   // @@protoc_insertion_point(field_add:google.protobuf.FileDescriptorProto.service)
-  return _internal_add_service();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::ServiceDescriptorProto >&
 FileDescriptorProto::service() const {
@@ -6868,8 +7064,9 @@
   return extension_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::FieldDescriptorProto* FileDescriptorProto::add_extension() {
+  PROTOBUF_NAMESPACE_ID::FieldDescriptorProto* _add = _internal_add_extension();
   // @@protoc_insertion_point(field_add:google.protobuf.FileDescriptorProto.extension)
-  return _internal_add_extension();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::FieldDescriptorProto >&
 FileDescriptorProto::extension() const {
@@ -6937,8 +7134,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::FileOptions* FileDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::FileOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void FileDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::FileOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -7020,8 +7218,9 @@
   return source_code_info_;
 }
 inline PROTOBUF_NAMESPACE_ID::SourceCodeInfo* FileDescriptorProto::mutable_source_code_info() {
+  PROTOBUF_NAMESPACE_ID::SourceCodeInfo* _msg = _internal_mutable_source_code_info();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileDescriptorProto.source_code_info)
-  return _internal_mutable_source_code_info();
+  return _msg;
 }
 inline void FileDescriptorProto::set_allocated_source_code_info(PROTOBUF_NAMESPACE_ID::SourceCodeInfo* source_code_info) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -7067,8 +7266,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.syntax)
 }
 inline std::string* FileDescriptorProto::mutable_syntax() {
+  std::string* _s = _internal_mutable_syntax();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileDescriptorProto.syntax)
-  return _internal_mutable_syntax();
+  return _s;
 }
 inline const std::string& FileDescriptorProto::_internal_syntax() const {
   return syntax_.Get();
@@ -7220,8 +7420,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* DescriptorProto_ExtensionRange::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.DescriptorProto.ExtensionRange.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void DescriptorProto_ExtensionRange::set_allocated_options(PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -7331,8 +7532,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.DescriptorProto.name)
 }
 inline std::string* DescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.DescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& DescriptorProto::_internal_name() const {
   return name_.Get();
@@ -7394,8 +7596,9 @@
   return field_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::FieldDescriptorProto* DescriptorProto::add_field() {
+  PROTOBUF_NAMESPACE_ID::FieldDescriptorProto* _add = _internal_add_field();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.field)
-  return _internal_add_field();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::FieldDescriptorProto >&
 DescriptorProto::field() const {
@@ -7433,8 +7636,9 @@
   return extension_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::FieldDescriptorProto* DescriptorProto::add_extension() {
+  PROTOBUF_NAMESPACE_ID::FieldDescriptorProto* _add = _internal_add_extension();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.extension)
-  return _internal_add_extension();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::FieldDescriptorProto >&
 DescriptorProto::extension() const {
@@ -7472,8 +7676,9 @@
   return nested_type_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::DescriptorProto* DescriptorProto::add_nested_type() {
+  PROTOBUF_NAMESPACE_ID::DescriptorProto* _add = _internal_add_nested_type();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.nested_type)
-  return _internal_add_nested_type();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::DescriptorProto >&
 DescriptorProto::nested_type() const {
@@ -7511,8 +7716,9 @@
   return enum_type_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::EnumDescriptorProto* DescriptorProto::add_enum_type() {
+  PROTOBUF_NAMESPACE_ID::EnumDescriptorProto* _add = _internal_add_enum_type();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.enum_type)
-  return _internal_add_enum_type();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::EnumDescriptorProto >&
 DescriptorProto::enum_type() const {
@@ -7550,8 +7756,9 @@
   return extension_range_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange* DescriptorProto::add_extension_range() {
+  PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange* _add = _internal_add_extension_range();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.extension_range)
-  return _internal_add_extension_range();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange >&
 DescriptorProto::extension_range() const {
@@ -7589,8 +7796,9 @@
   return oneof_decl_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::OneofDescriptorProto* DescriptorProto::add_oneof_decl() {
+  PROTOBUF_NAMESPACE_ID::OneofDescriptorProto* _add = _internal_add_oneof_decl();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.oneof_decl)
-  return _internal_add_oneof_decl();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::OneofDescriptorProto >&
 DescriptorProto::oneof_decl() const {
@@ -7658,8 +7866,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::MessageOptions* DescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::MessageOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.DescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void DescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::MessageOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -7711,8 +7920,9 @@
   return reserved_range_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::DescriptorProto_ReservedRange* DescriptorProto::add_reserved_range() {
+  PROTOBUF_NAMESPACE_ID::DescriptorProto_ReservedRange* _add = _internal_add_reserved_range();
   // @@protoc_insertion_point(field_add:google.protobuf.DescriptorProto.reserved_range)
-  return _internal_add_reserved_range();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::DescriptorProto_ReservedRange >&
 DescriptorProto::reserved_range() const {
@@ -7731,8 +7941,9 @@
   reserved_name_.Clear();
 }
 inline std::string* DescriptorProto::add_reserved_name() {
+  std::string* _s = _internal_add_reserved_name();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.DescriptorProto.reserved_name)
-  return _internal_add_reserved_name();
+  return _s;
 }
 inline const std::string& DescriptorProto::_internal_reserved_name(int index) const {
   return reserved_name_.Get(index);
@@ -7746,12 +7957,12 @@
   return reserved_name_.Mutable(index);
 }
 inline void DescriptorProto::set_reserved_name(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.DescriptorProto.reserved_name)
   reserved_name_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.DescriptorProto.reserved_name)
 }
 inline void DescriptorProto::set_reserved_name(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.DescriptorProto.reserved_name)
   reserved_name_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.DescriptorProto.reserved_name)
 }
 inline void DescriptorProto::set_reserved_name(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
@@ -7828,8 +8039,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* ExtensionRangeOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.ExtensionRangeOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 ExtensionRangeOptions::uninterpreted_option() const {
@@ -7865,8 +8077,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FieldDescriptorProto.name)
 }
 inline std::string* FieldDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FieldDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& FieldDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -8008,8 +8221,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FieldDescriptorProto.type_name)
 }
 inline std::string* FieldDescriptorProto::mutable_type_name() {
+  std::string* _s = _internal_mutable_type_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FieldDescriptorProto.type_name)
-  return _internal_mutable_type_name();
+  return _s;
 }
 inline const std::string& FieldDescriptorProto::_internal_type_name() const {
   return type_name_.Get();
@@ -8065,8 +8279,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FieldDescriptorProto.extendee)
 }
 inline std::string* FieldDescriptorProto::mutable_extendee() {
+  std::string* _s = _internal_mutable_extendee();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FieldDescriptorProto.extendee)
-  return _internal_mutable_extendee();
+  return _s;
 }
 inline const std::string& FieldDescriptorProto::_internal_extendee() const {
   return extendee_.Get();
@@ -8122,8 +8337,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FieldDescriptorProto.default_value)
 }
 inline std::string* FieldDescriptorProto::mutable_default_value() {
+  std::string* _s = _internal_mutable_default_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FieldDescriptorProto.default_value)
-  return _internal_mutable_default_value();
+  return _s;
 }
 inline const std::string& FieldDescriptorProto::_internal_default_value() const {
   return default_value_.Get();
@@ -8207,8 +8423,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FieldDescriptorProto.json_name)
 }
 inline std::string* FieldDescriptorProto::mutable_json_name() {
+  std::string* _s = _internal_mutable_json_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FieldDescriptorProto.json_name)
-  return _internal_mutable_json_name();
+  return _s;
 }
 inline const std::string& FieldDescriptorProto::_internal_json_name() const {
   return json_name_.Get();
@@ -8300,8 +8517,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::FieldOptions* FieldDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::FieldOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FieldDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void FieldDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::FieldOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -8379,8 +8597,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.OneofDescriptorProto.name)
 }
 inline std::string* OneofDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.OneofDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& OneofDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -8472,8 +8691,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::OneofOptions* OneofDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::OneofOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.OneofDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void OneofDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::OneofOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -8583,8 +8803,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.EnumDescriptorProto.name)
 }
 inline std::string* EnumDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.EnumDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& EnumDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -8646,8 +8867,9 @@
   return value_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::EnumValueDescriptorProto* EnumDescriptorProto::add_value() {
+  PROTOBUF_NAMESPACE_ID::EnumValueDescriptorProto* _add = _internal_add_value();
   // @@protoc_insertion_point(field_add:google.protobuf.EnumDescriptorProto.value)
-  return _internal_add_value();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::EnumValueDescriptorProto >&
 EnumDescriptorProto::value() const {
@@ -8715,8 +8937,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::EnumOptions* EnumDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::EnumOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.EnumDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void EnumDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::EnumOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -8768,8 +8991,9 @@
   return reserved_range_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::EnumDescriptorProto_EnumReservedRange* EnumDescriptorProto::add_reserved_range() {
+  PROTOBUF_NAMESPACE_ID::EnumDescriptorProto_EnumReservedRange* _add = _internal_add_reserved_range();
   // @@protoc_insertion_point(field_add:google.protobuf.EnumDescriptorProto.reserved_range)
-  return _internal_add_reserved_range();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::EnumDescriptorProto_EnumReservedRange >&
 EnumDescriptorProto::reserved_range() const {
@@ -8788,8 +9012,9 @@
   reserved_name_.Clear();
 }
 inline std::string* EnumDescriptorProto::add_reserved_name() {
+  std::string* _s = _internal_add_reserved_name();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.EnumDescriptorProto.reserved_name)
-  return _internal_add_reserved_name();
+  return _s;
 }
 inline const std::string& EnumDescriptorProto::_internal_reserved_name(int index) const {
   return reserved_name_.Get(index);
@@ -8803,12 +9028,12 @@
   return reserved_name_.Mutable(index);
 }
 inline void EnumDescriptorProto::set_reserved_name(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.EnumDescriptorProto.reserved_name)
   reserved_name_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.EnumDescriptorProto.reserved_name)
 }
 inline void EnumDescriptorProto::set_reserved_name(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.EnumDescriptorProto.reserved_name)
   reserved_name_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.EnumDescriptorProto.reserved_name)
 }
 inline void EnumDescriptorProto::set_reserved_name(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
@@ -8879,8 +9104,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.EnumValueDescriptorProto.name)
 }
 inline std::string* EnumValueDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.EnumValueDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& EnumValueDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -9000,8 +9226,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::EnumValueOptions* EnumValueDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::EnumValueOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.EnumValueDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void EnumValueDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::EnumValueOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -9051,8 +9278,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.ServiceDescriptorProto.name)
 }
 inline std::string* ServiceDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.ServiceDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& ServiceDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -9114,8 +9342,9 @@
   return method_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::MethodDescriptorProto* ServiceDescriptorProto::add_method() {
+  PROTOBUF_NAMESPACE_ID::MethodDescriptorProto* _add = _internal_add_method();
   // @@protoc_insertion_point(field_add:google.protobuf.ServiceDescriptorProto.method)
-  return _internal_add_method();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::MethodDescriptorProto >&
 ServiceDescriptorProto::method() const {
@@ -9183,8 +9412,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::ServiceOptions* ServiceDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::ServiceOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.ServiceDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void ServiceDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::ServiceOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -9234,8 +9464,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.MethodDescriptorProto.name)
 }
 inline std::string* MethodDescriptorProto::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.MethodDescriptorProto.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& MethodDescriptorProto::_internal_name() const {
   return name_.Get();
@@ -9291,8 +9522,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.MethodDescriptorProto.input_type)
 }
 inline std::string* MethodDescriptorProto::mutable_input_type() {
+  std::string* _s = _internal_mutable_input_type();
   // @@protoc_insertion_point(field_mutable:google.protobuf.MethodDescriptorProto.input_type)
-  return _internal_mutable_input_type();
+  return _s;
 }
 inline const std::string& MethodDescriptorProto::_internal_input_type() const {
   return input_type_.Get();
@@ -9348,8 +9580,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.MethodDescriptorProto.output_type)
 }
 inline std::string* MethodDescriptorProto::mutable_output_type() {
+  std::string* _s = _internal_mutable_output_type();
   // @@protoc_insertion_point(field_mutable:google.protobuf.MethodDescriptorProto.output_type)
-  return _internal_mutable_output_type();
+  return _s;
 }
 inline const std::string& MethodDescriptorProto::_internal_output_type() const {
   return output_type_.Get();
@@ -9441,8 +9674,9 @@
   return options_;
 }
 inline PROTOBUF_NAMESPACE_ID::MethodOptions* MethodDescriptorProto::mutable_options() {
+  PROTOBUF_NAMESPACE_ID::MethodOptions* _msg = _internal_mutable_options();
   // @@protoc_insertion_point(field_mutable:google.protobuf.MethodDescriptorProto.options)
-  return _internal_mutable_options();
+  return _msg;
 }
 inline void MethodDescriptorProto::set_allocated_options(PROTOBUF_NAMESPACE_ID::MethodOptions* options) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -9548,8 +9782,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.java_package)
 }
 inline std::string* FileOptions::mutable_java_package() {
+  std::string* _s = _internal_mutable_java_package();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.java_package)
-  return _internal_mutable_java_package();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_java_package() const {
   return java_package_.Get();
@@ -9605,8 +9840,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.java_outer_classname)
 }
 inline std::string* FileOptions::mutable_java_outer_classname() {
+  std::string* _s = _internal_mutable_java_outer_classname();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.java_outer_classname)
-  return _internal_mutable_java_outer_classname();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_java_outer_classname() const {
   return java_outer_classname_.Get();
@@ -9775,8 +10011,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.go_package)
 }
 inline std::string* FileOptions::mutable_go_package() {
+  std::string* _s = _internal_mutable_go_package();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.go_package)
-  return _internal_mutable_go_package();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_go_package() const {
   return go_package_.Get();
@@ -10000,8 +10237,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.objc_class_prefix)
 }
 inline std::string* FileOptions::mutable_objc_class_prefix() {
+  std::string* _s = _internal_mutable_objc_class_prefix();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.objc_class_prefix)
-  return _internal_mutable_objc_class_prefix();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_objc_class_prefix() const {
   return objc_class_prefix_.Get();
@@ -10057,8 +10295,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.csharp_namespace)
 }
 inline std::string* FileOptions::mutable_csharp_namespace() {
+  std::string* _s = _internal_mutable_csharp_namespace();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.csharp_namespace)
-  return _internal_mutable_csharp_namespace();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_csharp_namespace() const {
   return csharp_namespace_.Get();
@@ -10114,8 +10353,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.swift_prefix)
 }
 inline std::string* FileOptions::mutable_swift_prefix() {
+  std::string* _s = _internal_mutable_swift_prefix();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.swift_prefix)
-  return _internal_mutable_swift_prefix();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_swift_prefix() const {
   return swift_prefix_.Get();
@@ -10171,8 +10411,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.php_class_prefix)
 }
 inline std::string* FileOptions::mutable_php_class_prefix() {
+  std::string* _s = _internal_mutable_php_class_prefix();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.php_class_prefix)
-  return _internal_mutable_php_class_prefix();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_php_class_prefix() const {
   return php_class_prefix_.Get();
@@ -10228,8 +10469,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.php_namespace)
 }
 inline std::string* FileOptions::mutable_php_namespace() {
+  std::string* _s = _internal_mutable_php_namespace();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.php_namespace)
-  return _internal_mutable_php_namespace();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_php_namespace() const {
   return php_namespace_.Get();
@@ -10285,8 +10527,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.php_metadata_namespace)
 }
 inline std::string* FileOptions::mutable_php_metadata_namespace() {
+  std::string* _s = _internal_mutable_php_metadata_namespace();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.php_metadata_namespace)
-  return _internal_mutable_php_metadata_namespace();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_php_metadata_namespace() const {
   return php_metadata_namespace_.Get();
@@ -10342,8 +10585,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.ruby_package)
 }
 inline std::string* FileOptions::mutable_ruby_package() {
+  std::string* _s = _internal_mutable_ruby_package();
   // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.ruby_package)
-  return _internal_mutable_ruby_package();
+  return _s;
 }
 inline const std::string& FileOptions::_internal_ruby_package() const {
   return ruby_package_.Get();
@@ -10405,8 +10649,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* FileOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.FileOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 FileOptions::uninterpreted_option() const {
@@ -10560,8 +10805,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* MessageOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.MessageOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 MessageOptions::uninterpreted_option() const {
@@ -10773,8 +11019,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* FieldOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.FieldOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 FieldOptions::uninterpreted_option() const {
@@ -10816,8 +11063,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* OneofOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.OneofOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 OneofOptions::uninterpreted_option() const {
@@ -10915,8 +11163,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* EnumOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.EnumOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 EnumOptions::uninterpreted_option() const {
@@ -10986,8 +11235,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* EnumValueOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.EnumValueOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 EnumValueOptions::uninterpreted_option() const {
@@ -11057,8 +11307,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* ServiceOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.ServiceOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 ServiceOptions::uninterpreted_option() const {
@@ -11157,8 +11408,9 @@
   return uninterpreted_option_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption* MethodOptions::add_uninterpreted_option() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption* _add = _internal_add_uninterpreted_option();
   // @@protoc_insertion_point(field_add:google.protobuf.MethodOptions.uninterpreted_option)
-  return _internal_add_uninterpreted_option();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption >&
 MethodOptions::uninterpreted_option() const {
@@ -11194,8 +11446,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.UninterpretedOption.NamePart.name_part)
 }
 inline std::string* UninterpretedOption_NamePart::mutable_name_part() {
+  std::string* _s = _internal_mutable_name_part();
   // @@protoc_insertion_point(field_mutable:google.protobuf.UninterpretedOption.NamePart.name_part)
-  return _internal_mutable_name_part();
+  return _s;
 }
 inline const std::string& UninterpretedOption_NamePart::_internal_name_part() const {
   return name_part_.Get();
@@ -11289,8 +11542,9 @@
   return name_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::UninterpretedOption_NamePart* UninterpretedOption::add_name() {
+  PROTOBUF_NAMESPACE_ID::UninterpretedOption_NamePart* _add = _internal_add_name();
   // @@protoc_insertion_point(field_add:google.protobuf.UninterpretedOption.name)
-  return _internal_add_name();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::UninterpretedOption_NamePart >&
 UninterpretedOption::name() const {
@@ -11322,8 +11576,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.UninterpretedOption.identifier_value)
 }
 inline std::string* UninterpretedOption::mutable_identifier_value() {
+  std::string* _s = _internal_mutable_identifier_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.UninterpretedOption.identifier_value)
-  return _internal_mutable_identifier_value();
+  return _s;
 }
 inline const std::string& UninterpretedOption::_internal_identifier_value() const {
   return identifier_value_.Get();
@@ -11463,8 +11718,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.UninterpretedOption.string_value)
 }
 inline std::string* UninterpretedOption::mutable_string_value() {
+  std::string* _s = _internal_mutable_string_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.UninterpretedOption.string_value)
-  return _internal_mutable_string_value();
+  return _s;
 }
 inline const std::string& UninterpretedOption::_internal_string_value() const {
   return string_value_.Get();
@@ -11520,8 +11776,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.UninterpretedOption.aggregate_value)
 }
 inline std::string* UninterpretedOption::mutable_aggregate_value() {
+  std::string* _s = _internal_mutable_aggregate_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.UninterpretedOption.aggregate_value)
-  return _internal_mutable_aggregate_value();
+  return _s;
 }
 inline const std::string& UninterpretedOption::_internal_aggregate_value() const {
   return aggregate_value_.Get();
@@ -11675,8 +11932,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.SourceCodeInfo.Location.leading_comments)
 }
 inline std::string* SourceCodeInfo_Location::mutable_leading_comments() {
+  std::string* _s = _internal_mutable_leading_comments();
   // @@protoc_insertion_point(field_mutable:google.protobuf.SourceCodeInfo.Location.leading_comments)
-  return _internal_mutable_leading_comments();
+  return _s;
 }
 inline const std::string& SourceCodeInfo_Location::_internal_leading_comments() const {
   return leading_comments_.Get();
@@ -11732,8 +11990,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.SourceCodeInfo.Location.trailing_comments)
 }
 inline std::string* SourceCodeInfo_Location::mutable_trailing_comments() {
+  std::string* _s = _internal_mutable_trailing_comments();
   // @@protoc_insertion_point(field_mutable:google.protobuf.SourceCodeInfo.Location.trailing_comments)
-  return _internal_mutable_trailing_comments();
+  return _s;
 }
 inline const std::string& SourceCodeInfo_Location::_internal_trailing_comments() const {
   return trailing_comments_.Get();
@@ -11776,8 +12035,9 @@
   leading_detached_comments_.Clear();
 }
 inline std::string* SourceCodeInfo_Location::add_leading_detached_comments() {
+  std::string* _s = _internal_add_leading_detached_comments();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
-  return _internal_add_leading_detached_comments();
+  return _s;
 }
 inline const std::string& SourceCodeInfo_Location::_internal_leading_detached_comments(int index) const {
   return leading_detached_comments_.Get(index);
@@ -11791,12 +12051,12 @@
   return leading_detached_comments_.Mutable(index);
 }
 inline void SourceCodeInfo_Location::set_leading_detached_comments(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
   leading_detached_comments_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
 }
 inline void SourceCodeInfo_Location::set_leading_detached_comments(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
   leading_detached_comments_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
 }
 inline void SourceCodeInfo_Location::set_leading_detached_comments(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
@@ -11873,8 +12133,9 @@
   return location_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::SourceCodeInfo_Location* SourceCodeInfo::add_location() {
+  PROTOBUF_NAMESPACE_ID::SourceCodeInfo_Location* _add = _internal_add_location();
   // @@protoc_insertion_point(field_add:google.protobuf.SourceCodeInfo.location)
-  return _internal_add_location();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::SourceCodeInfo_Location >&
 SourceCodeInfo::location() const {
@@ -11957,8 +12218,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.GeneratedCodeInfo.Annotation.source_file)
 }
 inline std::string* GeneratedCodeInfo_Annotation::mutable_source_file() {
+  std::string* _s = _internal_mutable_source_file();
   // @@protoc_insertion_point(field_mutable:google.protobuf.GeneratedCodeInfo.Annotation.source_file)
-  return _internal_mutable_source_file();
+  return _s;
 }
 inline const std::string& GeneratedCodeInfo_Annotation::_internal_source_file() const {
   return source_file_.Get();
@@ -12080,8 +12342,9 @@
   return annotation_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo_Annotation* GeneratedCodeInfo::add_annotation() {
+  PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo_Annotation* _add = _internal_add_annotation();
   // @@protoc_insertion_point(field_add:google.protobuf.GeneratedCodeInfo.annotation)
-  return _internal_add_annotation();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo_Annotation >&
 GeneratedCodeInfo::annotation() const {
diff --git a/src/google/protobuf/duration.pb.cc b/src/google/protobuf/duration.pb.cc
index 164d295..d889cc1 100644
--- a/src/google/protobuf/duration.pb.cc
+++ b/src/google/protobuf/duration.pb.cc
@@ -81,10 +81,13 @@
  public:
 };
 
-Duration::Duration(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Duration::Duration(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Duration)
 }
 Duration::Duration(const Duration& from)
@@ -96,7 +99,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Duration)
 }
 
-void Duration::SharedCtor() {
+inline void Duration::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&seconds_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&nanos_) -
@@ -105,11 +108,12 @@
 
 Duration::~Duration() {
   // @@protoc_insertion_point(destructor:google.protobuf.Duration)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Duration::SharedDtor() {
+inline void Duration::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -235,25 +239,22 @@
   return total_size;
 }
 
-void Duration::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Duration)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Duration* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Duration>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Duration)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Duration)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Duration::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Duration::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Duration::GetClassData() const { return &_class_data_; }
+
+void Duration::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Duration *>(to)->MergeFrom(
+      static_cast<const Duration &>(from));
 }
 
+
 void Duration::MergeFrom(const Duration& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Duration)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -263,13 +264,7 @@
   if (from.nanos() != 0) {
     _internal_set_nanos(from._internal_nanos());
   }
-}
-
-void Duration::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Duration)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Duration::CopyFrom(const Duration& from) {
diff --git a/src/google/protobuf/duration.pb.h b/src/google/protobuf/duration.pb.h
index ef343d9..580733c 100644
--- a/src/google/protobuf/duration.pb.h
+++ b/src/google/protobuf/duration.pb.h
@@ -137,10 +137,13 @@
   Duration* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Duration>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Duration& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Duration& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -160,12 +163,16 @@
     return "google.protobuf.Duration";
   }
   protected:
-  explicit Duration(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Duration(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
diff --git a/src/google/protobuf/empty.pb.cc b/src/google/protobuf/empty.pb.cc
index 15761e9..c86ecc1 100644
--- a/src/google/protobuf/empty.pb.cc
+++ b/src/google/protobuf/empty.pb.cc
@@ -76,10 +76,13 @@
  public:
 };
 
-Empty::Empty(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Empty::Empty(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Empty)
 }
 Empty::Empty(const Empty& from)
@@ -88,16 +91,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Empty)
 }
 
-void Empty::SharedCtor() {
+inline void Empty::SharedCtor() {
 }
 
 Empty::~Empty() {
   // @@protoc_insertion_point(destructor:google.protobuf.Empty)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Empty::SharedDtor() {
+inline void Empty::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -175,35 +179,26 @@
   return total_size;
 }
 
-void Empty::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Empty)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Empty* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Empty>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Empty)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Empty)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Empty::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Empty::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Empty::GetClassData() const { return &_class_data_; }
+
+void Empty::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Empty *>(to)->MergeFrom(
+      static_cast<const Empty &>(from));
 }
 
+
 void Empty::MergeFrom(const Empty& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Empty)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
-}
-
-void Empty::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Empty)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Empty::CopyFrom(const Empty& from) {
diff --git a/src/google/protobuf/empty.pb.h b/src/google/protobuf/empty.pb.h
index 40a77fe..12e5971 100644
--- a/src/google/protobuf/empty.pb.h
+++ b/src/google/protobuf/empty.pb.h
@@ -137,10 +137,13 @@
   Empty* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Empty>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Empty& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Empty& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -160,12 +163,16 @@
     return "google.protobuf.Empty";
   }
   protected:
-  explicit Empty(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Empty(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
diff --git a/src/google/protobuf/extension_set.cc b/src/google/protobuf/extension_set.cc
index 5814dc9..bad23a6 100644
--- a/src/google/protobuf/extension_set.cc
+++ b/src/google/protobuf/extension_set.cc
@@ -616,6 +616,10 @@
     ClearExtension(number);
     return;
   }
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+  GOOGLE_DCHECK(message->GetOwningArena() == nullptr ||
+         message->GetOwningArena() == arena_);
+#endif  // PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
   Arena* message_arena = message->GetOwningArena();
   Extension* extension;
   if (MaybeNewExtension(number, descriptor, &extension)) {
@@ -1054,7 +1058,11 @@
 }
 
 void ExtensionSet::Swap(ExtensionSet* x) {
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  if (GetArena() != nullptr && GetArena() == x->GetArena()) {
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
   if (GetArena() == x->GetArena()) {
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
     InternalSwap(x);
   } else {
     // TODO(cfallin, rohananil): We maybe able to optimize a case where we are
@@ -1079,52 +1087,59 @@
 
 void ExtensionSet::SwapExtension(ExtensionSet* other, int number) {
   if (this == other) return;
+
+  if (GetArena() == other->GetArena()) {
+    UnsafeShallowSwapExtension(other, number);
+    return;
+  }
+
   Extension* this_ext = FindOrNull(number);
   Extension* other_ext = other->FindOrNull(number);
 
-  if (this_ext == NULL && other_ext == NULL) {
-    return;
-  }
+  if (this_ext == other_ext) return;
 
-  if (this_ext != NULL && other_ext != NULL) {
-    if (GetArena() == other->GetArena()) {
-      using std::swap;
-      swap(*this_ext, *other_ext);
-    } else {
-      // TODO(cfallin, rohananil): We could further optimize these cases,
-      // especially avoid creation of ExtensionSet, and move MergeFrom logic
-      // into Extensions itself (which takes arena as an argument).
-      // We do it this way to reuse the copy-across-arenas logic already
-      // implemented in ExtensionSet's MergeFrom.
-      ExtensionSet temp;
-      temp.InternalExtensionMergeFrom(number, *other_ext);
-      Extension* temp_ext = temp.FindOrNull(number);
-      other_ext->Clear();
-      other->InternalExtensionMergeFrom(number, *this_ext);
-      this_ext->Clear();
-      InternalExtensionMergeFrom(number, *temp_ext);
-    }
-    return;
-  }
-
-  if (this_ext == NULL) {
-    if (GetArena() == other->GetArena()) {
-      *Insert(number).first = *other_ext;
-    } else {
-      InternalExtensionMergeFrom(number, *other_ext);
-    }
+  if (this_ext != nullptr && other_ext != nullptr) {
+    // TODO(cfallin, rohananil): We could further optimize these cases,
+    // especially avoid creation of ExtensionSet, and move MergeFrom logic
+    // into Extensions itself (which takes arena as an argument).
+    // We do it this way to reuse the copy-across-arenas logic already
+    // implemented in ExtensionSet's MergeFrom.
+    ExtensionSet temp;
+    temp.InternalExtensionMergeFrom(number, *other_ext);
+    Extension* temp_ext = temp.FindOrNull(number);
+    other_ext->Clear();
+    other->InternalExtensionMergeFrom(number, *this_ext);
+    this_ext->Clear();
+    InternalExtensionMergeFrom(number, *temp_ext);
+  } else if (this_ext == nullptr) {
+    InternalExtensionMergeFrom(number, *other_ext);
+    if (other->GetArena() == nullptr) other_ext->Free();
     other->Erase(number);
-    return;
-  }
-
-  if (other_ext == NULL) {
-    if (GetArena() == other->GetArena()) {
-      *other->Insert(number).first = *this_ext;
-    } else {
-      other->InternalExtensionMergeFrom(number, *this_ext);
-    }
+  } else {
+    other->InternalExtensionMergeFrom(number, *this_ext);
+    if (GetArena() == nullptr) this_ext->Free();
     Erase(number);
-    return;
+  }
+}
+
+void ExtensionSet::UnsafeShallowSwapExtension(ExtensionSet* other, int number) {
+  if (this == other) return;
+
+  Extension* this_ext = FindOrNull(number);
+  Extension* other_ext = other->FindOrNull(number);
+
+  if (this_ext == other_ext) return;
+
+  GOOGLE_DCHECK_EQ(GetArena(), other->GetArena());
+
+  if (this_ext != nullptr && other_ext != nullptr) {
+    std::swap(*this_ext, *other_ext);
+  } else if (this_ext == nullptr) {
+    *Insert(number).first = *other_ext;
+    other->Erase(number);
+  } else {
+    *other->Insert(number).first = *this_ext;
+    Erase(number);
   }
 }
 
@@ -1725,7 +1740,7 @@
 }
 
 // This function deletes all allocated objects. This function should be only
-// called if the Extension was created with an arena.
+// called if the Extension was created without an arena.
 void ExtensionSet::Extension::Free() {
   if (is_repeated) {
     switch (cpp_type(type)) {
diff --git a/src/google/protobuf/extension_set.h b/src/google/protobuf/extension_set.h
index acfe47d..e3d1669 100644
--- a/src/google/protobuf/extension_set.h
+++ b/src/google/protobuf/extension_set.h
@@ -282,12 +282,12 @@
   void UnsafeArenaSetAllocatedMessage(int number, FieldType type,
                                       const FieldDescriptor* descriptor,
                                       MessageLite* message);
-  PROTOBUF_FUTURE_MUST_USE_RESULT MessageLite* ReleaseMessage(
+  PROTOBUF_MUST_USE_RESULT MessageLite* ReleaseMessage(
       int number, const MessageLite& prototype);
   MessageLite* UnsafeArenaReleaseMessage(int number,
                                          const MessageLite& prototype);
 
-  PROTOBUF_FUTURE_MUST_USE_RESULT MessageLite* ReleaseMessage(
+  PROTOBUF_MUST_USE_RESULT MessageLite* ReleaseMessage(
       const FieldDescriptor* descriptor, MessageFactory* factory);
   MessageLite* UnsafeArenaReleaseMessage(const FieldDescriptor* descriptor,
                                          MessageFactory* factory);
@@ -355,7 +355,7 @@
 #undef desc
 
   void RemoveLast(int number);
-  PROTOBUF_FUTURE_MUST_USE_RESULT MessageLite* ReleaseLast(int number);
+  PROTOBUF_MUST_USE_RESULT MessageLite* ReleaseLast(int number);
   void SwapElements(int number, int index1, int index2);
 
   // -----------------------------------------------------------------
@@ -372,6 +372,7 @@
   void Swap(ExtensionSet* other);
   void InternalSwap(ExtensionSet* other);
   void SwapExtension(ExtensionSet* other, int number);
+  void UnsafeShallowSwapExtension(ExtensionSet* other, int number);
   bool IsInitialized() const;
 
   // Parses a single extension from the input. The input should start out
@@ -535,7 +536,7 @@
     virtual MessageLite* MutableMessage(const MessageLite& prototype) = 0;
     virtual void SetAllocatedMessage(MessageLite* message) = 0;
     virtual void UnsafeArenaSetAllocatedMessage(MessageLite* message) = 0;
-    virtual PROTOBUF_FUTURE_MUST_USE_RESULT MessageLite* ReleaseMessage(
+    virtual PROTOBUF_MUST_USE_RESULT MessageLite* ReleaseMessage(
         const MessageLite& prototype) = 0;
     virtual MessageLite* UnsafeArenaReleaseMessage(
         const MessageLite& prototype) = 0;
@@ -1262,7 +1263,7 @@
                                              ExtensionSet* set) {
     set->UnsafeArenaSetAllocatedMessage(number, field_type, NULL, message);
   }
-  static inline PROTOBUF_FUTURE_MUST_USE_RESULT MutableType
+  static inline PROTOBUF_MUST_USE_RESULT MutableType
   Release(int number, FieldType /* field_type */, ExtensionSet* set) {
     return static_cast<Type*>(
         set->ReleaseMessage(number, Type::default_instance()));
@@ -1478,7 +1479,7 @@
   template <typename _proto_TypeTraits,                                       \
             ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
             bool _is_packed>                                                  \
-  inline PROTOBUF_FUTURE_MUST_USE_RESULT                                      \
+  inline PROTOBUF_MUST_USE_RESULT                                             \
       typename _proto_TypeTraits::Singular::MutableType                       \
       ReleaseExtension(                                                       \
           const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<       \
diff --git a/src/google/protobuf/field_mask.pb.cc b/src/google/protobuf/field_mask.pb.cc
index 1174f1e..a76cff2 100644
--- a/src/google/protobuf/field_mask.pb.cc
+++ b/src/google/protobuf/field_mask.pb.cc
@@ -79,11 +79,14 @@
  public:
 };
 
-FieldMask::FieldMask(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+FieldMask::FieldMask(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   paths_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FieldMask)
 }
 FieldMask::FieldMask(const FieldMask& from)
@@ -93,16 +96,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FieldMask)
 }
 
-void FieldMask::SharedCtor() {
+inline void FieldMask::SharedCtor() {
 }
 
 FieldMask::~FieldMask() {
   // @@protoc_insertion_point(destructor:google.protobuf.FieldMask)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FieldMask::SharedDtor() {
+inline void FieldMask::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -218,36 +222,27 @@
   return total_size;
 }
 
-void FieldMask::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FieldMask)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FieldMask* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FieldMask>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FieldMask)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FieldMask)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FieldMask::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FieldMask::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FieldMask::GetClassData() const { return &_class_data_; }
+
+void FieldMask::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FieldMask *>(to)->MergeFrom(
+      static_cast<const FieldMask &>(from));
 }
 
+
 void FieldMask::MergeFrom(const FieldMask& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FieldMask)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   paths_.MergeFrom(from.paths_);
-}
-
-void FieldMask::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FieldMask)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FieldMask::CopyFrom(const FieldMask& from) {
diff --git a/src/google/protobuf/field_mask.pb.h b/src/google/protobuf/field_mask.pb.h
index e71551e..ed49021 100644
--- a/src/google/protobuf/field_mask.pb.h
+++ b/src/google/protobuf/field_mask.pb.h
@@ -137,10 +137,13 @@
   FieldMask* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FieldMask>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FieldMask& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FieldMask& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -160,12 +163,16 @@
     return "google.protobuf.FieldMask";
   }
   protected:
-  explicit FieldMask(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FieldMask(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -232,8 +239,9 @@
   paths_.Clear();
 }
 inline std::string* FieldMask::add_paths() {
+  std::string* _s = _internal_add_paths();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.FieldMask.paths)
-  return _internal_add_paths();
+  return _s;
 }
 inline const std::string& FieldMask::_internal_paths(int index) const {
   return paths_.Get(index);
@@ -247,12 +255,12 @@
   return paths_.Mutable(index);
 }
 inline void FieldMask::set_paths(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.FieldMask.paths)
   paths_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.FieldMask.paths)
 }
 inline void FieldMask::set_paths(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.FieldMask.paths)
   paths_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.FieldMask.paths)
 }
 inline void FieldMask::set_paths(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
diff --git a/src/google/protobuf/generated_message_reflection.cc b/src/google/protobuf/generated_message_reflection.cc
index ea3c71d..e743dd1 100644
--- a/src/google/protobuf/generated_message_reflection.cc
+++ b/src/google/protobuf/generated_message_reflection.cc
@@ -359,6 +359,176 @@
   return total_size;
 }
 
+namespace internal {
+
+class SwapFieldHelper {
+ public:
+  template <bool unsafe_shallow_swap>
+  static void SwapRepeatedStringField(const Reflection* r, Message* lhs,
+                                      Message* rhs,
+                                      const FieldDescriptor* field);
+
+  template <bool unsafe_shallow_swap>
+  static void SwapStringField(const Reflection* r, Message* lhs, Message* rhs,
+                              const FieldDescriptor* field);
+
+  static void SwapArenaStringPtr(const std::string* default_ptr,
+                                 ArenaStringPtr* lhs, Arena* lhs_arena,
+                                 ArenaStringPtr* rhs, Arena* rhs_arena);
+
+  template <bool unsafe_shallow_swap>
+  static void SwapRepeatedMessageField(const Reflection* r, Message* lhs,
+                                       Message* rhs,
+                                       const FieldDescriptor* field);
+
+  template <bool unsafe_shallow_swap>
+  static void SwapMessageField(const Reflection* r, Message* lhs, Message* rhs,
+                               const FieldDescriptor* field);
+
+  static void SwapMessage(const Reflection* r, Message* lhs, Arena* lhs_arena,
+                          Message* rhs, Arena* rhs_arena,
+                          const FieldDescriptor* field);
+};
+
+template <bool unsafe_shallow_swap>
+void SwapFieldHelper::SwapRepeatedStringField(const Reflection* r, Message* lhs,
+                                              Message* rhs,
+                                              const FieldDescriptor* field) {
+  switch (field->options().ctype()) {
+    default:
+    case FieldOptions::STRING: {
+      auto* lhs_string = r->MutableRaw<RepeatedPtrFieldBase>(lhs, field);
+      auto* rhs_string = r->MutableRaw<RepeatedPtrFieldBase>(rhs, field);
+      if (unsafe_shallow_swap) {
+        lhs_string->InternalSwap(rhs_string);
+      } else {
+        lhs_string->Swap<GenericTypeHandler<std::string>>(rhs_string);
+      }
+      break;
+    }
+  }
+}
+
+template <bool unsafe_shallow_swap>
+void SwapFieldHelper::SwapStringField(const Reflection* r, Message* lhs,
+                                      Message* rhs,
+                                      const FieldDescriptor* field) {
+  switch (field->options().ctype()) {
+    default:
+    case FieldOptions::STRING: {
+      ArenaStringPtr* lhs_string = r->MutableRaw<ArenaStringPtr>(lhs, field);
+      ArenaStringPtr* rhs_string = r->MutableRaw<ArenaStringPtr>(rhs, field);
+      if (unsafe_shallow_swap) {
+        ArenaStringPtr::UnsafeShallowSwap(lhs_string, rhs_string);
+      } else {
+        SwapFieldHelper::SwapArenaStringPtr(
+            r->DefaultRaw<ArenaStringPtr>(field).GetPointer(),  //
+            lhs_string, lhs->GetArenaForAllocation(),           //
+            rhs_string, rhs->GetArenaForAllocation());
+      }
+      break;
+    }
+  }
+}
+
+void SwapFieldHelper::SwapArenaStringPtr(const std::string* default_ptr,
+                                         ArenaStringPtr* lhs, Arena* lhs_arena,
+                                         ArenaStringPtr* rhs,
+                                         Arena* rhs_arena) {
+  if (lhs_arena == rhs_arena) {
+    ArenaStringPtr::InternalSwap(default_ptr, lhs, lhs_arena, rhs, rhs_arena);
+  } else if (lhs->IsDefault(default_ptr) && rhs->IsDefault(default_ptr)) {
+    // Nothing to do.
+  } else if (lhs->IsDefault(default_ptr)) {
+    lhs->Set(default_ptr, rhs->Get(), lhs_arena);
+    // rhs needs to be destroyed before overwritten.
+    rhs->Destroy(default_ptr, rhs_arena);
+    rhs->UnsafeSetDefault(default_ptr);
+  } else if (rhs->IsDefault(default_ptr)) {
+    rhs->Set(default_ptr, lhs->Get(), rhs_arena);
+    // lhs needs to be destroyed before overwritten.
+    lhs->Destroy(default_ptr, lhs_arena);
+    lhs->UnsafeSetDefault(default_ptr);
+  } else {
+    std::string temp = lhs->Get();
+    lhs->Set(default_ptr, rhs->Get(), lhs_arena);
+    rhs->Set(default_ptr, std::move(temp), rhs_arena);
+  }
+}
+
+template <bool unsafe_shallow_swap>
+void SwapFieldHelper::SwapRepeatedMessageField(const Reflection* r,
+                                               Message* lhs, Message* rhs,
+                                               const FieldDescriptor* field) {
+  if (IsMapFieldInApi(field)) {
+    auto* lhs_map = r->MutableRaw<MapFieldBase>(lhs, field);
+    auto* rhs_map = r->MutableRaw<MapFieldBase>(rhs, field);
+    if (unsafe_shallow_swap) {
+      lhs_map->UnsafeShallowSwap(rhs_map);
+    } else {
+      lhs_map->Swap(rhs_map);
+    }
+  } else {
+    auto* lhs_rm = r->MutableRaw<RepeatedPtrFieldBase>(lhs, field);
+    auto* rhs_rm = r->MutableRaw<RepeatedPtrFieldBase>(rhs, field);
+    if (unsafe_shallow_swap) {
+      lhs_rm->InternalSwap(rhs_rm);
+    } else {
+      lhs_rm->Swap<GenericTypeHandler<Message>>(rhs_rm);
+    }
+  }
+}
+
+template <bool unsafe_shallow_swap>
+void SwapFieldHelper::SwapMessageField(const Reflection* r, Message* lhs,
+                                       Message* rhs,
+                                       const FieldDescriptor* field) {
+  if (unsafe_shallow_swap) {
+    std::swap(*r->MutableRaw<Message*>(lhs, field),
+              *r->MutableRaw<Message*>(rhs, field));
+  } else {
+    SwapMessage(r, lhs, lhs->GetArenaForAllocation(), rhs,
+                rhs->GetArenaForAllocation(), field);
+  }
+}
+
+void SwapFieldHelper::SwapMessage(const Reflection* r, Message* lhs,
+                                  Arena* lhs_arena, Message* rhs,
+                                  Arena* rhs_arena,
+                                  const FieldDescriptor* field) {
+  Message** lhs_sub = r->MutableRaw<Message*>(lhs, field);
+  Message** rhs_sub = r->MutableRaw<Message*>(rhs, field);
+
+  if (*lhs_sub == *rhs_sub) return;
+
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  if (lhs_arena != nullptr && lhs_arena == rhs_arena) {
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
+  if (lhs_arena == rhs_arena) {
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
+    std::swap(*lhs_sub, *rhs_sub);
+    return;
+  }
+
+  if (*lhs_sub != nullptr && *rhs_sub != nullptr) {
+    (*lhs_sub)->GetReflection()->Swap(*lhs_sub, *rhs_sub);
+  } else if (*lhs_sub == nullptr) {
+    *lhs_sub = (*rhs_sub)->New(lhs_arena);
+    (*lhs_sub)->CopyFrom(**rhs_sub);
+    r->ClearField(rhs, field);
+    // Ensures has bit is unchanged after ClearField.
+    r->SetBit(rhs, field);
+  } else {
+    *rhs_sub = (*lhs_sub)->New(rhs_arena);
+    (*rhs_sub)->CopyFrom(**lhs_sub);
+    r->ClearField(lhs, field);
+    // Ensures has bit is unchanged after ClearField.
+    r->SetBit(lhs, field);
+  }
+}
+
+}  // namespace internal
+
 void Reflection::SwapField(Message* message1, Message* message2,
                            const FieldDescriptor* field) const {
   if (field->is_repeated()) {
@@ -380,24 +550,12 @@
 #undef SWAP_ARRAYS
 
       case FieldDescriptor::CPPTYPE_STRING:
-        switch (field->options().ctype()) {
-          default:  // TODO(kenton):  Support other string reps.
-          case FieldOptions::STRING:
-            MutableRaw<RepeatedPtrFieldBase>(message1, field)
-                ->Swap<GenericTypeHandler<std::string> >(
-                    MutableRaw<RepeatedPtrFieldBase>(message2, field));
-            break;
-        }
+        internal::SwapFieldHelper::SwapRepeatedStringField<false>(
+            this, message1, message2, field);
         break;
       case FieldDescriptor::CPPTYPE_MESSAGE:
-        if (IsMapFieldInApi(field)) {
-          MutableRaw<MapFieldBase>(message1, field)
-              ->Swap(MutableRaw<MapFieldBase>(message2, field));
-        } else {
-          MutableRaw<RepeatedPtrFieldBase>(message1, field)
-              ->Swap<GenericTypeHandler<Message> >(
-                  MutableRaw<RepeatedPtrFieldBase>(message2, field));
-        }
+        internal::SwapFieldHelper::SwapRepeatedMessageField<false>(
+            this, message1, message2, field);
         break;
 
       default:
@@ -421,70 +579,13 @@
       SWAP_VALUES(ENUM, int);
 #undef SWAP_VALUES
       case FieldDescriptor::CPPTYPE_MESSAGE:
-        if (message1->GetArenaForAllocation() ==
-            message2->GetArenaForAllocation()) {
-          std::swap(*MutableRaw<Message*>(message1, field),
-                    *MutableRaw<Message*>(message2, field));
-        } else {
-          Message** sub_msg1 = MutableRaw<Message*>(message1, field);
-          Message** sub_msg2 = MutableRaw<Message*>(message2, field);
-          if (*sub_msg1 == nullptr && *sub_msg2 == nullptr) break;
-          if (*sub_msg1 && *sub_msg2) {
-            (*sub_msg1)->GetReflection()->Swap(*sub_msg1, *sub_msg2);
-            break;
-          }
-          if (*sub_msg1 == nullptr) {
-            *sub_msg1 = (*sub_msg2)->New(message1->GetArenaForAllocation());
-            (*sub_msg1)->CopyFrom(**sub_msg2);
-            ClearField(message2, field);
-            // Ensures has bit is unchanged after ClearField.
-            SetBit(message2, field);
-          } else {
-            *sub_msg2 = (*sub_msg1)->New(message2->GetArenaForAllocation());
-            (*sub_msg2)->CopyFrom(**sub_msg1);
-            ClearField(message1, field);
-            // Ensures has bit is unchanged after ClearField.
-            SetBit(message1, field);
-          }
-        }
+        internal::SwapFieldHelper::SwapMessageField<false>(this, message1,
+                                                           message2, field);
         break;
 
       case FieldDescriptor::CPPTYPE_STRING:
-        switch (field->options().ctype()) {
-          default:  // TODO(kenton):  Support other string reps.
-          case FieldOptions::STRING: {
-            const std::string* default_ptr =
-                DefaultRaw<ArenaStringPtr>(field).GetPointer();
-            Arena* arena1 = message1->GetArenaForAllocation();
-            Arena* arena2 = message2->GetArenaForAllocation();
-
-            ArenaStringPtr* string1 =
-                MutableRaw<ArenaStringPtr>(message1, field);
-            ArenaStringPtr* string2 =
-                MutableRaw<ArenaStringPtr>(message2, field);
-            if (message1->GetOwningArena() == message2->GetOwningArena()) {
-              ArenaStringPtr::InternalSwap(default_ptr, string1, arena1,
-                                           string2, arena2);
-            } else if (string1->IsDefault(default_ptr) &&
-                       string2->IsDefault(default_ptr)) {
-              // Nothing to do.
-            } else if (string1->IsDefault(default_ptr)) {
-              string1->Set(default_ptr, string2->Get(), arena1);
-              // string2 needs to be destroyed before overwritten.
-              string2->Destroy(default_ptr, arena2);
-              string2->UnsafeSetDefault(default_ptr);
-            } else if (string2->IsDefault(default_ptr)) {
-              string2->Set(default_ptr, string1->Get(), arena2);
-              // string1 needs to be destroyed before overwritten.
-              string1->Destroy(default_ptr, arena1);
-              string1->UnsafeSetDefault(default_ptr);
-            } else {
-              std::string temp = string1->Get();
-              string1->Set(default_ptr, string2->Get(), arena1);
-              string2->Set(default_ptr, std::move(temp), arena2);
-            }
-          } break;
-        }
+        internal::SwapFieldHelper::SwapStringField<false>(this, message1,
+                                                          message2, field);
         break;
 
       default:
@@ -493,6 +594,55 @@
   }
 }
 
+void Reflection::UnsafeShallowSwapField(Message* message1, Message* message2,
+                                        const FieldDescriptor* field) const {
+  GOOGLE_DCHECK_EQ(message1->GetArenaForAllocation(),
+            message2->GetArenaForAllocation());
+
+  if (!field->is_repeated()) {
+    if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+      internal::SwapFieldHelper::SwapMessageField<true>(this, message1,
+                                                        message2, field);
+    } else if (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING) {
+      internal::SwapFieldHelper::SwapStringField<true>(this, message1, message2,
+                                                       field);
+    } else {
+      SwapField(message1, message2, field);
+    }
+    return;
+  }
+
+  switch (field->cpp_type()) {
+#define SHALLOW_SWAP_ARRAYS(CPPTYPE, TYPE)                                \
+  case FieldDescriptor::CPPTYPE_##CPPTYPE:                                \
+    MutableRaw<RepeatedField<TYPE>>(message1, field)                      \
+        ->InternalSwap(MutableRaw<RepeatedField<TYPE>>(message2, field)); \
+    break;
+
+    SHALLOW_SWAP_ARRAYS(INT32, int32);
+    SHALLOW_SWAP_ARRAYS(INT64, int64);
+    SHALLOW_SWAP_ARRAYS(UINT32, uint32);
+    SHALLOW_SWAP_ARRAYS(UINT64, uint64);
+    SHALLOW_SWAP_ARRAYS(FLOAT, float);
+    SHALLOW_SWAP_ARRAYS(DOUBLE, double);
+    SHALLOW_SWAP_ARRAYS(BOOL, bool);
+    SHALLOW_SWAP_ARRAYS(ENUM, int);
+#undef SHALLOW_SWAP_ARRAYS
+
+    case FieldDescriptor::CPPTYPE_STRING:
+      internal::SwapFieldHelper::SwapRepeatedStringField<true>(this, message1,
+                                                               message2, field);
+      break;
+    case FieldDescriptor::CPPTYPE_MESSAGE:
+      internal::SwapFieldHelper::SwapRepeatedMessageField<true>(
+          this, message1, message2, field);
+      break;
+
+    default:
+      GOOGLE_LOG(FATAL) << "Unimplemented type: " << field->cpp_type();
+  }
+}
+
 void Reflection::SwapOneofField(Message* message1, Message* message2,
                                 const OneofDescriptor* oneof_descriptor) const {
   GOOGLE_DCHECK(!oneof_descriptor->is_synthetic());
@@ -609,6 +759,45 @@
   }
 }
 
+void Reflection::UnsafeShallowSwapOneofField(
+    Message* message1, Message* message2,
+    const OneofDescriptor* oneof_descriptor) const {
+  GOOGLE_DCHECK_EQ(message1->GetArenaForAllocation(),
+            message2->GetArenaForAllocation());
+
+  uint32 oneof_case1 = GetOneofCase(*message1, oneof_descriptor);
+  const FieldDescriptor* field1 =
+      oneof_case1 > 0 ? descriptor_->FindFieldByNumber(oneof_case1) : nullptr;
+  uint32 oneof_case2 = GetOneofCase(*message2, oneof_descriptor);
+  const FieldDescriptor* field2 =
+      oneof_case2 > 0 ? descriptor_->FindFieldByNumber(oneof_case2) : nullptr;
+
+  if ((field1 != nullptr &&
+       field1->cpp_type() != FieldDescriptor::CPPTYPE_MESSAGE) ||
+      (field2 != nullptr &&
+       field2->cpp_type() != FieldDescriptor::CPPTYPE_MESSAGE)) {
+    // Fallback to SwapOneofField for non-message fields.
+    SwapOneofField(message1, message2, oneof_descriptor);
+    return;
+  }
+
+  Message* temp_message =
+      oneof_case1 > 0 ? UnsafeArenaReleaseMessage(message1, field1) : nullptr;
+
+  if (oneof_case2 > 0) {
+    UnsafeArenaSetAllocatedMessage(
+        message1, UnsafeArenaReleaseMessage(message2, field2), field2);
+  } else {
+    ClearOneof(message1, oneof_descriptor);
+  }
+
+  if (oneof_case1 > 0) {
+    UnsafeArenaSetAllocatedMessage(message2, temp_message, field1);
+  } else {
+    ClearOneof(message2, oneof_descriptor);
+  }
+}
+
 void Reflection::Swap(Message* message1, Message* message2) const {
   if (message1 == message2) return;
 
@@ -632,7 +821,12 @@
 
   // Check that both messages are in the same arena (or both on the heap). We
   // need to copy all data if not, due to ownership semantics.
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  if (message1->GetOwningArena() == nullptr ||
+      message1->GetOwningArena() != message2->GetOwningArena()) {
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
   if (message1->GetOwningArena() != message2->GetOwningArena()) {
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
     // One of the two is guaranteed to have an arena.  Switch things around
     // to guarantee that message1 has an arena.
     Arena* arena = message1->GetOwningArena();
@@ -644,7 +838,12 @@
     Message* temp = message1->New(arena);
     temp->MergeFrom(*message2);
     message2->CopyFrom(*message1);
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+    message1->CopyFrom(*temp);
+    if (arena == nullptr) delete temp;
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
     Swap(message1, temp);
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
     return;
   }
 
@@ -691,7 +890,8 @@
   MutableUnknownFields(message1)->Swap(MutableUnknownFields(message2));
 }
 
-void Reflection::SwapFields(
+template <bool unsafe_shallow_swap>
+void Reflection::SwapFieldsImpl(
     Message* message1, Message* message2,
     const std::vector<const FieldDescriptor*>& fields) const {
   if (message1 == message2) return;
@@ -716,13 +916,16 @@
 
   std::set<int> swapped_oneof;
 
-  const int fields_size = static_cast<int>(fields.size());
-  for (int i = 0; i < fields_size; i++) {
-    const FieldDescriptor* field = fields[i];
+  for (const auto* field : fields) {
     CheckInvalidAccess(schema_, field);
     if (field->is_extension()) {
-      MutableExtensionSet(message1)->SwapExtension(
-          MutableExtensionSet(message2), field->number());
+      if (unsafe_shallow_swap) {
+        MutableExtensionSet(message1)->UnsafeShallowSwapExtension(
+            MutableExtensionSet(message2), field->number());
+      } else {
+        MutableExtensionSet(message1)->SwapExtension(
+            MutableExtensionSet(message2), field->number());
+      }
     } else {
       if (schema_.InRealOneof(field)) {
         int oneof_index = field->containing_oneof()->index();
@@ -731,10 +934,19 @@
           continue;
         }
         swapped_oneof.insert(oneof_index);
-        SwapOneofField(message1, message2, field->containing_oneof());
+        if (unsafe_shallow_swap) {
+          UnsafeShallowSwapOneofField(message1, message2,
+                                      field->containing_oneof());
+        } else {
+          SwapOneofField(message1, message2, field->containing_oneof());
+        }
       } else {
         // Swap field.
-        SwapField(message1, message2, field);
+        if (unsafe_shallow_swap) {
+          UnsafeShallowSwapField(message1, message2, field);
+        } else {
+          SwapField(message1, message2, field);
+        }
         // Swap has bit for non-repeated fields.  We have already checked for
         // oneof already. This has to be done after SwapField, because SwapField
         // may depend on the information in has bits.
@@ -746,6 +958,18 @@
   }
 }
 
+void Reflection::SwapFields(
+    Message* message1, Message* message2,
+    const std::vector<const FieldDescriptor*>& fields) const {
+  SwapFieldsImpl<false>(message1, message2, fields);
+}
+
+void Reflection::UnsafeShallowSwapFields(
+    Message* message1, Message* message2,
+    const std::vector<const FieldDescriptor*>& fields) const {
+  SwapFieldsImpl<true>(message1, message2, fields);
+}
+
 // -------------------------------------------------------------------
 
 bool Reflection::HasField(const Message& message,
@@ -1627,6 +1851,10 @@
 
 void Reflection::SetAllocatedMessage(Message* message, Message* sub_message,
                                      const FieldDescriptor* field) const {
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+  GOOGLE_DCHECK(sub_message->GetOwningArena() == nullptr ||
+         sub_message->GetOwningArena() == message->GetArenaForAllocation());
+#endif  // PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
   CheckInvalidAccess(schema_, field);
 
   // If message and sub-message are in different memory ownership domains
diff --git a/src/google/protobuf/generated_message_reflection_unittest.cc b/src/google/protobuf/generated_message_reflection_unittest.cc
index b4c013a..d5c68db 100644
--- a/src/google/protobuf/generated_message_reflection_unittest.cc
+++ b/src/google/protobuf/generated_message_reflection_unittest.cc
@@ -48,6 +48,8 @@
 
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/map_test_util.h>
+#include <google/protobuf/map_unittest.pb.h>
 #include <google/protobuf/test_util.h>
 #include <google/protobuf/unittest.pb.h>
 #include <google/protobuf/arena.h>
@@ -61,6 +63,15 @@
 namespace google {
 namespace protobuf {
 
+class GeneratedMessageReflectionTestHelper {
+ public:
+  static void UnsafeShallowSwapFields(
+      Message* lhs, Message* rhs,
+      const std::vector<const FieldDescriptor*>& fields) {
+    lhs->GetReflection()->UnsafeShallowSwapFields(lhs, rhs, fields);
+  }
+};
+
 namespace {
 
 // Shorthand to get a FieldDescriptor for a field of unittest::TestAllTypes.
@@ -314,6 +325,125 @@
   TestUtil::ExpectAllExtensionsSet(message2);
 }
 
+TEST(GeneratedMessageReflectionTest, SwapFieldsAllExtensionArenaHeap) {
+  Arena arena;
+
+  std::unique_ptr<unittest::TestAllExtensions> message1(
+      Arena::CreateMessage<unittest::TestAllExtensions>(nullptr));
+  auto* message2 = Arena::CreateMessage<unittest::TestAllExtensions>(&arena);
+
+  TestUtil::SetAllExtensions(message1.get());
+
+  std::vector<const FieldDescriptor*> fields;
+  const Reflection* reflection = message1->GetReflection();
+  reflection->ListFields(*message1, &fields);
+  reflection->SwapFields(message1.get(), message2, fields);
+
+  TestUtil::ExpectExtensionsClear(*message1);
+  TestUtil::ExpectAllExtensionsSet(*message2);
+}
+
+TEST(GeneratedMessageReflectionTest, UnsafeShallowSwapFieldsAll) {
+  Arena arena;
+  auto* message1 = Arena::CreateMessage<unittest::TestAllTypes>(&arena);
+  auto* message2 = Arena::CreateMessage<unittest::TestAllTypes>(&arena);
+
+  TestUtil::SetAllFields(message2);
+
+  auto* kept_nested_message_ptr = message2->mutable_optional_nested_message();
+  auto* kept_foreign_message_ptr = message2->mutable_optional_foreign_message();
+  auto* kept_repeated_nested_message_ptr =
+      message2->mutable_repeated_nested_message(0);
+  auto* kept_repeated_foreign_message_ptr =
+      message2->mutable_repeated_foreign_message(0);
+
+  std::vector<const FieldDescriptor*> fields;
+  const Reflection* reflection = message1->GetReflection();
+  reflection->ListFields(*message2, &fields);
+  GeneratedMessageReflectionTestHelper::UnsafeShallowSwapFields(
+      message1, message2, fields);
+
+  TestUtil::ExpectAllFieldsSet(*message1);
+  TestUtil::ExpectClear(*message2);
+
+  // Expects the swap to be shallow. Expects pointer stability to the element of
+  // the repeated fields (not the container).
+  EXPECT_EQ(kept_nested_message_ptr,
+            message1->mutable_optional_nested_message());
+  EXPECT_EQ(kept_foreign_message_ptr,
+            message1->mutable_optional_foreign_message());
+  EXPECT_EQ(kept_repeated_nested_message_ptr,
+            message1->mutable_repeated_nested_message(0));
+  EXPECT_EQ(kept_repeated_foreign_message_ptr,
+            message1->mutable_repeated_foreign_message(0));
+}
+
+TEST(GeneratedMessageReflectionTest, UnsafeShallowSwapFieldsMap) {
+  Arena arena;
+  auto* message1 = Arena::CreateMessage<unittest::TestMap>(&arena);
+  auto* message2 = Arena::CreateMessage<unittest::TestMap>(&arena);
+
+  MapTestUtil::SetMapFields(message2);
+
+  auto* kept_map_int32_fm_ptr =
+      &(*message2->mutable_map_int32_foreign_message())[0];
+
+  std::vector<const FieldDescriptor*> fields;
+  const Reflection* reflection = message1->GetReflection();
+  reflection->ListFields(*message2, &fields);
+  GeneratedMessageReflectionTestHelper::UnsafeShallowSwapFields(
+      message1, message2, fields);
+
+  MapTestUtil::ExpectMapFieldsSet(*message1);
+  MapTestUtil::ExpectClear(*message2);
+
+  // Expects the swap to be shallow.
+  EXPECT_EQ(kept_map_int32_fm_ptr,
+            &(*message1->mutable_map_int32_foreign_message())[0]);
+}
+
+TEST(GeneratedMessageReflectionTest, UnsafeShallowSwapFieldsAllExtension) {
+  Arena arena;
+  auto* message1 = Arena::CreateMessage<unittest::TestAllExtensions>(&arena);
+  auto* message2 = Arena::CreateMessage<unittest::TestAllExtensions>(&arena);
+
+  TestUtil::SetAllExtensions(message1);
+
+  auto* kept_nested_message_ext_ptr =
+      message1->MutableExtension(unittest::optional_nested_message_extension);
+  auto* kept_foreign_message_ext_ptr =
+      message1->MutableExtension(unittest::optional_foreign_message_extension);
+  auto* kept_repeated_nested_message_ext_ptr =
+      message1->MutableRepeatedExtension(
+          unittest::repeated_nested_message_extension);
+  auto* kept_repeated_foreign_message_ext_ptr =
+      message1->MutableRepeatedExtension(
+          unittest::repeated_foreign_message_extension);
+
+  std::vector<const FieldDescriptor*> fields;
+  const Reflection* reflection = message1->GetReflection();
+  reflection->ListFields(*message1, &fields);
+  GeneratedMessageReflectionTestHelper::UnsafeShallowSwapFields(
+      message1, message2, fields);
+
+  TestUtil::ExpectExtensionsClear(*message1);
+  TestUtil::ExpectAllExtensionsSet(*message2);
+
+  // Expects the swap to be shallow.
+  EXPECT_EQ(
+      kept_nested_message_ext_ptr,
+      message2->MutableExtension(unittest::optional_nested_message_extension));
+  EXPECT_EQ(
+      kept_foreign_message_ext_ptr,
+      message2->MutableExtension(unittest::optional_foreign_message_extension));
+  EXPECT_EQ(kept_repeated_nested_message_ext_ptr,
+            message2->MutableRepeatedExtension(
+                unittest::repeated_nested_message_extension));
+  EXPECT_EQ(kept_repeated_foreign_message_ext_ptr,
+            message2->MutableRepeatedExtension(
+                unittest::repeated_foreign_message_extension));
+}
+
 TEST(GeneratedMessageReflectionTest, SwapOneof) {
   unittest::TestOneof2 message1, message2;
   TestUtil::SetOneof1(&message1);
@@ -353,6 +483,46 @@
   TestUtil::ExpectOneofSet1(message2);
 }
 
+TEST(GeneratedMessageReflectionTest, UnsafeShallowSwapFieldsOneof) {
+  Arena arena;
+  auto* message1 = Arena::CreateMessage<unittest::TestOneof2>(&arena);
+  auto* message2 = Arena::CreateMessage<unittest::TestOneof2>(&arena);
+  TestUtil::SetOneof1(message1);
+
+  std::vector<const FieldDescriptor*> fields;
+  const Descriptor* descriptor = message1->GetDescriptor();
+  for (int i = 0; i < descriptor->field_count(); i++) {
+    fields.push_back(descriptor->field(i));
+  }
+  GeneratedMessageReflectionTestHelper::UnsafeShallowSwapFields(
+      message1, message2, fields);
+
+  TestUtil::ExpectOneofClear(*message1);
+  TestUtil::ExpectOneofSet1(*message2);
+}
+
+TEST(GeneratedMessageReflectionTest,
+     UnsafeShallowSwapFieldsOneofExpectShallow) {
+  Arena arena;
+  auto* message1 = Arena::CreateMessage<unittest::TestOneof2>(&arena);
+  auto* message2 = Arena::CreateMessage<unittest::TestOneof2>(&arena);
+  TestUtil::SetOneof1(message1);
+  message1->mutable_foo_message()->set_qux_int(1000);
+  auto* kept_foo_ptr = message1->mutable_foo_message();
+
+  std::vector<const FieldDescriptor*> fields;
+  const Descriptor* descriptor = message1->GetDescriptor();
+  for (int i = 0; i < descriptor->field_count(); i++) {
+    fields.push_back(descriptor->field(i));
+  }
+  GeneratedMessageReflectionTestHelper::UnsafeShallowSwapFields(
+      message1, message2, fields);
+
+  EXPECT_TRUE(message2->has_foo_message());
+  EXPECT_EQ(message2->foo_message().qux_int(), 1000);
+  EXPECT_EQ(kept_foo_ptr, message2->mutable_foo_message());
+}
+
 TEST(GeneratedMessageReflectionTest, RemoveLast) {
   unittest::TestAllTypes message;
   TestUtil::ReflectionTester reflection_tester(
diff --git a/src/google/protobuf/generated_message_tctable_decl.h b/src/google/protobuf/generated_message_tctable_decl.h
new file mode 100644
index 0000000..9d2bc40d
--- /dev/null
+++ b/src/google/protobuf/generated_message_tctable_decl.h
@@ -0,0 +1,123 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This file contains declarations needed in generated headers for messages
+// that use tail-call table parsing. Everything in this file is for internal
+// use only.
+
+#ifndef GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_DECL_H__
+#define GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_DECL_H__
+
+#include <cstdint>
+#include <type_traits>
+
+#include <google/protobuf/parse_context.h>
+#include <google/protobuf/message_lite.h>
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+// Additional information about this field:
+struct TcFieldData {
+  constexpr TcFieldData() : data(0) {}
+  constexpr TcFieldData(uint16_t coded_tag, uint8_t hasbit_idx, uint16_t offset)
+      : data(static_cast<uint64_t>(offset) << 48 |
+             static_cast<uint64_t>(hasbit_idx) << 16 | coded_tag) {}
+
+  uint16_t coded_tag() const { return static_cast<uint16_t>(data); }
+  uint8_t hasbit_idx() const { return static_cast<uint8_t>(data >> 16); }
+  uint16_t offset() const { return static_cast<uint16_t>(data >> 48); }
+
+  uint64_t data;
+};
+
+struct TailCallParseTableBase;
+
+// TailCallParseFunc is the function pointer type used in the tailcall table.
+typedef const char* (*TailCallParseFunc)(MessageLite* msg, const char* ptr,
+                                         ParseContext* ctx,
+                                         const TailCallParseTableBase* table,
+                                         uint64_t hasbits, TcFieldData data);
+
+// Base class for message-level table with info for the tail-call parser.
+struct TailCallParseTableBase {
+  // Common attributes for message layout:
+  uint16_t has_bits_offset;
+  uint16_t extension_offset;
+  uint32_t extension_range_low;
+  uint32_t extension_range_high;
+  uint32_t has_bits_required_mask;
+  const MessageLite* default_instance;
+
+  // Handler for fields which are not handled by table dispatch.
+  TailCallParseFunc fallback;
+
+  // Table entry for fast-path tailcall dispatch handling.
+  struct FieldEntry {
+    // Target function for dispatch:
+    TailCallParseFunc target;
+    // Field data used during parse:
+    TcFieldData bits;
+  };
+  // There is always at least one table entry.
+  const FieldEntry* table() const {
+    return reinterpret_cast<const FieldEntry*>(this + 1);
+  }
+};
+
+static_assert(sizeof(TailCallParseTableBase::FieldEntry) <= 16,
+              "Field entry is too big.");
+
+template <size_t kTableSizeLog2>
+struct TailCallParseTable {
+  TailCallParseTableBase header;
+
+  // Entries for each field.
+  //
+  // Fields are indexed by the lowest bits of their field number. The field
+  // number is masked to fit inside the table. Note that the parsing logic
+  // generally calls `TailCallParseTableBase::table()` instead of accessing
+  // this field directly.
+  TailCallParseTableBase::FieldEntry entries[(1 << kTableSizeLog2)];
+};
+
+static_assert(std::is_standard_layout<TailCallParseTable<1>>::value,
+              "TailCallParseTable must be standard layout.");
+
+static_assert(offsetof(TailCallParseTable<1>, entries) ==
+                  sizeof(TailCallParseTableBase),
+              "Table entries must be laid out after TailCallParseTableBase.");
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_DECL_H__
diff --git a/src/google/protobuf/generated_message_tctable_full.cc b/src/google/protobuf/generated_message_tctable_full.cc
new file mode 100644
index 0000000..634c663
--- /dev/null
+++ b/src/google/protobuf/generated_message_tctable_full.cc
@@ -0,0 +1,53 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <cstdint>
+
+#include <google/protobuf/parse_context.h>
+#include <google/protobuf/extension_set.h>
+#include <google/protobuf/generated_message_tctable_impl.h>
+#include <google/protobuf/message.h>
+#include <google/protobuf/unknown_field_set.h>
+
+// clang-format off
+#include <google/protobuf/port_def.inc>
+// clang-format on
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+const char* TcParserBase::GenericFallback(PROTOBUF_TC_PARAM_DECL) {
+  return GenericFallbackImpl<Message, UnknownFieldSet>(PROTOBUF_TC_PARAM_PASS);
+}
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/generated_message_tctable_impl.h b/src/google/protobuf/generated_message_tctable_impl.h
new file mode 100644
index 0000000..b4cf929
--- /dev/null
+++ b/src/google/protobuf/generated_message_tctable_impl.h
@@ -0,0 +1,245 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_IMPL_H__
+#define GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_IMPL_H__
+
+#include <cstdint>
+#include <type_traits>
+
+#include <google/protobuf/parse_context.h>
+#include <google/protobuf/extension_set.h>
+#include <google/protobuf/generated_message_tctable_decl.h>
+#include <google/protobuf/message_lite.h>
+#include <google/protobuf/metadata_lite.h>
+#include <google/protobuf/port.h>
+#include <google/protobuf/wire_format_lite.h>
+
+// Must come last:
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+
+class Message;
+class UnknownFieldSet;
+
+namespace internal {
+
+// PROTOBUF_TC_PARAM_DECL are the parameters for tailcall functions.
+//
+// Note that this is performance sensitive: changing the parameters will change
+// the registers used by the ABI calling convention, which subsequently affects
+// register selection logic inside the function.
+#define PROTOBUF_TC_PARAM_DECL                                 \
+  ::google::protobuf::MessageLite *msg, const char *ptr,                 \
+      ::google::protobuf::internal::ParseContext *ctx,                   \
+      const ::google::protobuf::internal::TailCallParseTableBase *table, \
+      uint64_t hasbits, ::google::protobuf::internal::TcFieldData data
+
+// PROTOBUF_TC_PARAM_PASS passes values to match PROTOBUF_TC_PARAM_DECL.
+#define PROTOBUF_TC_PARAM_PASS msg, ptr, ctx, table, hasbits, data
+
+class TcParserBase {
+ public:
+  static const char* GenericFallback(PROTOBUF_TC_PARAM_DECL);
+  static const char* GenericFallbackLite(PROTOBUF_TC_PARAM_DECL);
+
+  template <typename FieldType, typename TagType>
+  PROTOBUF_NOINLINE static const char* SingularParseMessage(
+      PROTOBUF_TC_PARAM_DECL) {
+    if (PROTOBUF_PREDICT_FALSE(static_cast<TagType>(data.coded_tag()) != 0)) {
+      return table->fallback(PROTOBUF_TC_PARAM_PASS);
+    }
+    ptr += sizeof(TagType);
+    hasbits |= (1 << data.hasbit_idx());
+    auto& field = RefAt<FieldType*>(msg, data.offset());
+    if (field == nullptr) {
+      auto arena = ctx->data().arena;
+      if (Arena::is_arena_constructable<FieldType>::value) {
+        field = Arena::CreateMessage<FieldType>(arena);
+      } else {
+        field = Arena::Create<FieldType>(arena);
+      }
+    }
+    SyncHasbits(msg, hasbits, table);
+    return ctx->ParseMessage(field, ptr);
+  }
+
+  template <typename FieldType, typename TagType>
+  PROTOBUF_NOINLINE static const char* RepeatedParseMessage(
+      PROTOBUF_TC_PARAM_DECL) {
+    if (PROTOBUF_PREDICT_FALSE(static_cast<TagType>(data.coded_tag()) != 0)) {
+      return table->fallback(PROTOBUF_TC_PARAM_PASS);
+    }
+    ptr += sizeof(TagType);
+    auto& field = RefAt<RepeatedPtrField<FieldType>>(msg, data.offset());
+    SyncHasbits(msg, hasbits, table);
+    ptr = ctx->ParseMessage(field.Add(), ptr);
+    return ptr;
+  }
+
+  template <typename LayoutType, typename TagType>
+  static const char* RepeatedFixed(PROTOBUF_TC_PARAM_DECL);
+  template <typename LayoutType, typename TagType>
+  static const char* PackedFixed(PROTOBUF_TC_PARAM_DECL);
+
+ protected:
+  template <typename T>
+  static T& RefAt(void* x, size_t offset) {
+    T* target = reinterpret_cast<T*>(static_cast<char*>(x) + offset);
+    GOOGLE_DCHECK_EQ(0, reinterpret_cast<uintptr_t>(target) % alignof(T));
+    return *target;
+  }
+
+  static inline PROTOBUF_ALWAYS_INLINE void SyncHasbits(
+      MessageLite* msg, uint64_t hasbits, const TailCallParseTableBase* table) {
+    const uint32_t has_bits_offset = table->has_bits_offset;
+    if (has_bits_offset) {
+      // Only the first 32 has-bits are updated. Nothing above those is stored,
+      // but e.g. messages without has-bits update the upper bits.
+      RefAt<uint32_t>(msg, has_bits_offset) = static_cast<uint32_t>(hasbits);
+    }
+  }
+
+  static inline PROTOBUF_ALWAYS_INLINE const char* Return(
+      PROTOBUF_TC_PARAM_DECL) {
+    SyncHasbits(msg, hasbits, table);
+    return ptr;
+  }
+
+  static inline PROTOBUF_ALWAYS_INLINE const char* Error(
+      PROTOBUF_TC_PARAM_DECL) {
+    SyncHasbits(msg, hasbits, table);
+    return nullptr;
+  }
+
+  class ScopedArenaSwap final {
+   public:
+    ScopedArenaSwap(MessageLite* msg, ParseContext* ctx)
+        : ctx_(ctx), saved_(ctx->data().arena) {
+      ctx_->data().arena = msg->GetArenaForAllocation();
+    }
+    ScopedArenaSwap(const ScopedArenaSwap&) = delete;
+    ~ScopedArenaSwap() { ctx_->data().arena = saved_; }
+
+   private:
+    ParseContext* const ctx_;
+    Arena* const saved_;
+  };
+
+  template <class MessageBaseT, class UnknownFieldsT>
+  static const char* GenericFallbackImpl(PROTOBUF_TC_PARAM_DECL) {
+#define CHK_(x) \
+  if (PROTOBUF_PREDICT_FALSE(!(x))) return nullptr /* NOLINT */
+
+    SyncHasbits(msg, hasbits, table);
+    uint32_t tag;
+    ptr = ::PROTOBUF_NAMESPACE_ID::internal::ReadTag(ptr, &tag);
+    CHK_(ptr);
+    if ((tag & 7) == WireFormatLite::WIRETYPE_END_GROUP || tag == 0) {
+      ctx->SetLastTag(tag);
+      return ptr;
+    }
+    uint32_t num = tag >> 3;
+    if (table->extension_range_low <= num &&
+        num <= table->extension_range_high) {
+      return RefAt<ExtensionSet>(msg, table->extension_offset)
+          .ParseField(tag, ptr,
+                      static_cast<const MessageBaseT*>(table->default_instance),
+                      &msg->_internal_metadata_, ctx);
+    }
+    return UnknownFieldParse(
+        tag, msg->_internal_metadata_.mutable_unknown_fields<UnknownFieldsT>(),
+        ptr, ctx);
+#undef CHK_
+  }
+};
+
+// TcParser implements most of the parsing logic for tailcall tables.
+//
+// This is templated on lg2(table size), since dispatching depends upon the size
+// of the table. The template parameter avoids runtime overhead for computing
+// the table entry index.
+template <uint32_t kPowerOf2>
+struct TcParser final : TcParserBase {
+  // Dispatch to the designated parse function
+  inline PROTOBUF_ALWAYS_INLINE static const char* TagDispatch(
+      PROTOBUF_TC_PARAM_DECL) {
+    const auto coded_tag = UnalignedLoad<uint16_t>(ptr);
+    constexpr size_t kIdxMask = ((1 << (kPowerOf2)) - 1);
+    const size_t idx = (coded_tag >> 3) & kIdxMask;
+    data = table->table()[idx].bits;
+    data.data ^= coded_tag;
+    PROTOBUF_MUSTTAIL return table->table()[idx].target(PROTOBUF_TC_PARAM_PASS);
+  }
+
+  // We can only safely call from field to next field if the call is optimized
+  // to a proper tail call. Otherwise we blow through stack. Clang and gcc
+  // reliably do this optimization in opt mode, but do not perform this in debug
+  // mode. Luckily the structure of the algorithm is such that it's always
+  // possible to just return and use the enclosing parse loop as a trampoline.
+  static const char* TailCall(PROTOBUF_TC_PARAM_DECL) {
+    constexpr bool always_return = !PROTOBUF_TAILCALL;
+    if (always_return || !ctx->DataAvailable(ptr)) {
+      PROTOBUF_MUSTTAIL return Return(PROTOBUF_TC_PARAM_PASS);
+    }
+    PROTOBUF_MUSTTAIL return TagDispatch(PROTOBUF_TC_PARAM_PASS);
+  }
+
+  static const char* ParseLoop(MessageLite* msg, const char* ptr,
+                               ParseContext* ctx,
+                               const TailCallParseTableBase* table) {
+    ScopedArenaSwap saved(msg, ctx);
+    const uint32_t has_bits_offset = table->has_bits_offset;
+    while (!ctx->Done(&ptr)) {
+      uint64_t hasbits = 0;
+      if (has_bits_offset) hasbits = RefAt<uint32_t>(msg, has_bits_offset);
+      ptr = TagDispatch(msg, ptr, ctx, table, hasbits, {});
+      if (ptr == nullptr) break;
+      if (ctx->LastTag() != 1) break;  // Ended on terminating tag
+    }
+    return ptr;
+  }
+
+  template <typename LayoutType, typename TagType>
+  static const char* SingularFixed(PROTOBUF_TC_PARAM_DECL);
+};
+
+// Declare helper functions:
+#include <google/protobuf/generated_message_tctable_impl.inc>
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_IMPL_H__
diff --git a/src/google/protobuf/generated_message_tctable_impl.inc b/src/google/protobuf/generated_message_tctable_impl.inc
new file mode 100644
index 0000000..2e3dbf2
--- /dev/null
+++ b/src/google/protobuf/generated_message_tctable_impl.inc
@@ -0,0 +1,91 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// clang-format off
+#ifdef PROTOBUF_TCT_SOURCE
+template const char* TcParser<1>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<2>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<3>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<4>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<5>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::RepeatedFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::PackedFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<1>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<2>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<3>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<4>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<5>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::RepeatedFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::PackedFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<1>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<2>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<3>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<4>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<5>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::RepeatedFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::PackedFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<1>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<2>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<3>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<4>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParser<5>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::RepeatedFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+template const char* TcParserBase::PackedFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+#else
+extern template const char* TcParser<1>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<2>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<3>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<4>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<5>::SingularFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::RepeatedFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::PackedFixed<uint64_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<1>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<2>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<3>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<4>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<5>::SingularFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::RepeatedFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::PackedFixed<uint32_t, uint8_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<1>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<2>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<3>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<4>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<5>::SingularFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::RepeatedFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::PackedFixed<uint64_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<1>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<2>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<3>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<4>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParser<5>::SingularFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::RepeatedFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+extern template const char* TcParserBase::PackedFixed<uint32_t, uint16_t>(PROTOBUF_TC_PARAM_DECL);
+#endif
+// clang-format on
diff --git a/src/google/protobuf/generated_message_tctable_lite.cc b/src/google/protobuf/generated_message_tctable_lite.cc
new file mode 100644
index 0000000..9eb5d5a
--- /dev/null
+++ b/src/google/protobuf/generated_message_tctable_lite.cc
@@ -0,0 +1,148 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <cstdint>
+
+#include <google/protobuf/parse_context.h>
+#include <google/protobuf/extension_set.h>
+#include <google/protobuf/generated_message_tctable_decl.h>
+#include <google/protobuf/generated_message_tctable_impl.h>
+#include <google/protobuf/message_lite.h>
+#include <google/protobuf/wire_format_lite.h>
+
+// clang-format off
+#include <google/protobuf/port_def.inc>
+// clang-format on
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+const char* TcParserBase::GenericFallbackLite(PROTOBUF_TC_PARAM_DECL) {
+  return GenericFallbackImpl<MessageLite, std::string>(PROTOBUF_TC_PARAM_PASS);
+}
+
+namespace {
+
+// Offset returns the address `offset` bytes after `base`.
+inline void* Offset(void* base, uint32_t offset) {
+  return static_cast<uint8*>(base) + offset;
+}
+
+// InvertPacked changes tag bits from the given wire type to length
+// delimited. This is the difference expected between packed and non-packed
+// repeated fields.
+template <WireFormatLite::WireType Wt>
+inline PROTOBUF_ALWAYS_INLINE void InvertPacked(TcFieldData& data) {
+  data.data ^= Wt ^ WireFormatLite::WIRETYPE_LENGTH_DELIMITED;
+}
+
+}  // namespace
+
+//////////////////////////////////////////////////////////////////////////////
+// Fixed fields
+//////////////////////////////////////////////////////////////////////////////
+
+template <uint32_t kPowerOf2>
+template <typename LayoutType, typename TagType>
+const char* TcParser<kPowerOf2>::SingularFixed(PROTOBUF_TC_PARAM_DECL) {
+  if (PROTOBUF_PREDICT_FALSE(static_cast<TagType>(data.coded_tag()) != 0)) {
+    return table->fallback(PROTOBUF_TC_PARAM_PASS);
+  }
+  ptr += sizeof(TagType);  // Consume tag
+  hasbits |= (1 << data.hasbit_idx());
+  std::memcpy(Offset(msg, data.offset()), ptr, sizeof(LayoutType));
+  ptr += sizeof(LayoutType);
+  // TailCall syncs any pending hasbits:
+  PROTOBUF_MUSTTAIL return TailCall(PROTOBUF_TC_PARAM_PASS);
+}
+
+template <typename LayoutType, typename TagType>
+const char* TcParserBase::RepeatedFixed(PROTOBUF_TC_PARAM_DECL) {
+  if (PROTOBUF_PREDICT_FALSE(static_cast<TagType>(data.coded_tag()) != 0)) {
+    // Check if the field can be parsed as packed repeated:
+    constexpr WireFormatLite::WireType fallback_wt =
+        sizeof(LayoutType) == 4 ? WireFormatLite::WIRETYPE_FIXED32
+                                : WireFormatLite::WIRETYPE_FIXED64;
+    InvertPacked<fallback_wt>(data);
+    if (static_cast<TagType>(data.coded_tag()) == 0) {
+      return PackedFixed<LayoutType, TagType>(PROTOBUF_TC_PARAM_PASS);
+    } else {
+      return table->fallback(PROTOBUF_TC_PARAM_PASS);
+    }
+  }
+  auto& field = RefAt<RepeatedField<LayoutType>>(msg, data.offset());
+  int idx = field.size();
+  auto elem = field.Add();
+  int space = field.Capacity() - idx;
+  idx = 0;
+  auto expected_tag = UnalignedLoad<TagType>(ptr);
+  do {
+    ptr += sizeof(TagType);
+    std::memcpy(elem + (idx++), ptr, sizeof(LayoutType));
+    ptr += sizeof(LayoutType);
+    if (idx >= space) break;
+    if (!ctx->DataAvailable(ptr)) break;
+  } while (UnalignedLoad<TagType>(ptr) == expected_tag);
+  field.AddNAlreadyReserved(idx - 1);
+  return Return(PROTOBUF_TC_PARAM_PASS);
+}
+
+template <typename LayoutType, typename TagType>
+const char* TcParserBase::PackedFixed(PROTOBUF_TC_PARAM_DECL) {
+  if (PROTOBUF_PREDICT_FALSE(static_cast<TagType>(data.coded_tag()) != 0)) {
+    // Try parsing as non-packed repeated:
+    constexpr WireFormatLite::WireType fallback_wt =
+        sizeof(LayoutType) == 4 ? WireFormatLite::WIRETYPE_FIXED32
+                                : WireFormatLite::WIRETYPE_FIXED64;
+    InvertPacked<fallback_wt>(data);
+    if (static_cast<TagType>(data.coded_tag()) == 0) {
+      return RepeatedFixed<LayoutType, TagType>(PROTOBUF_TC_PARAM_PASS);
+    } else {
+      return table->fallback(PROTOBUF_TC_PARAM_PASS);
+    }
+  }
+  ptr += sizeof(TagType);
+  // Since ctx->ReadPackedFixed does not use TailCall<> or Return<>, sync any
+  // pending hasbits now:
+  SyncHasbits(msg, hasbits, table);
+  auto& field = RefAt<RepeatedField<LayoutType>>(msg, data.offset());
+  int size = ReadSize(&ptr);
+  // TODO(dlj): add a tailcalling variant of ReadPackedFixed.
+  return ctx->ReadPackedFixed(ptr, size,
+                              static_cast<RepeatedField<LayoutType>*>(&field));
+}
+
+#define PROTOBUF_TCT_SOURCE
+#include <google/protobuf/generated_message_tctable_impl.inc>
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/generated_message_util.cc b/src/google/protobuf/generated_message_util.cc
index 4fd6211..605fa98 100644
--- a/src/google/protobuf/generated_message_util.cc
+++ b/src/google/protobuf/generated_message_util.cc
@@ -721,6 +721,9 @@
   GOOGLE_DCHECK(Arena::InternalHelper<MessageLite>::GetOwningArena(submessage) ==
          submessage_arena);
   GOOGLE_DCHECK(message_arena != submessage_arena);
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+  GOOGLE_DCHECK_EQ(submessage_arena, nullptr);
+#endif  // PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
   if (message_arena != NULL && submessage_arena == NULL) {
     message_arena->Own(submessage);
     return submessage;
diff --git a/src/google/protobuf/map_entry.h b/src/google/protobuf/map_entry.h
index 9e35795..87bc000 100644
--- a/src/google/protobuf/map_entry.h
+++ b/src/google/protobuf/map_entry.h
@@ -99,7 +99,7 @@
                      kValueFieldType>(arena),
         _internal_metadata_(arena) {}
   ~MapEntry() {
-    Message::_internal_metadata_.Delete<UnknownFieldSet>();
+    Message::_internal_metadata_.template Delete<UnknownFieldSet>();
     _internal_metadata_.Delete<UnknownFieldSet>();
   }
   typedef void InternalArenaConstructable_;
diff --git a/src/google/protobuf/map_field.cc b/src/google/protobuf/map_field.cc
index 1afdc9d..d94b278 100644
--- a/src/google/protobuf/map_field.cc
+++ b/src/google/protobuf/map_field.cc
@@ -61,6 +61,11 @@
   InternalSwap(other);
 }
 
+void MapFieldBase::UnsafeShallowSwap(MapFieldBase* other) {
+  GOOGLE_DCHECK_EQ(arena_, other->arena_);
+  InternalSwap(other);
+}
+
 void MapFieldBase::InternalSwap(MapFieldBase* other) {
   std::swap(arena_, other->arena_);
   std::swap(repeated_field_, other->repeated_field_);
diff --git a/src/google/protobuf/map_field.h b/src/google/protobuf/map_field.h
index 5f357b3..7f52cc7 100644
--- a/src/google/protobuf/map_field.h
+++ b/src/google/protobuf/map_field.h
@@ -366,6 +366,7 @@
   virtual void MapEnd(MapIterator* map_iter) const = 0;
   virtual void MergeFrom(const MapFieldBase& other) = 0;
   virtual void Swap(MapFieldBase* other);
+  virtual void UnsafeShallowSwap(MapFieldBase* other);
   // Sync Map with repeated field and returns the size of map.
   virtual int size() const = 0;
   virtual void Clear() = 0;
@@ -442,6 +443,7 @@
   friend class ContendedMapCleanTest;
   friend class GeneratedMessageReflection;
   friend class MapFieldAccessor;
+  friend class ::PROTOBUF_NAMESPACE_ID::Reflection;
   friend class ::PROTOBUF_NAMESPACE_ID::DynamicMessage;
 
   // Virtual helper methods for MapIterator. MapIterator doesn't have the
@@ -567,6 +569,7 @@
   void Clear() override;
   void MergeFrom(const MapFieldBase& other) override;
   void Swap(MapFieldBase* other) override;
+  void UnsafeShallowSwap(MapFieldBase* other) override;
   void InternalSwap(MapField* other);
 
   // Used in the implementation of parsing. Caller should take the ownership iff
@@ -649,6 +652,7 @@
   bool DeleteMapValue(const MapKey& map_key) override;
   void MergeFrom(const MapFieldBase& other) override;
   void Swap(MapFieldBase* other) override;
+  void UnsafeShallowSwap(MapFieldBase* other) override { Swap(other); }
 
   const Map<MapKey, MapValueRef>& GetMap() const override;
   Map<MapKey, MapValueRef>* MutableMap() override;
diff --git a/src/google/protobuf/map_field_inl.h b/src/google/protobuf/map_field_inl.h
index 82206c6..a42b4fc 100644
--- a/src/google/protobuf/map_field_inl.h
+++ b/src/google/protobuf/map_field_inl.h
@@ -285,6 +285,14 @@
 template <typename Derived, typename Key, typename T,
           WireFormatLite::FieldType kKeyFieldType,
           WireFormatLite::FieldType kValueFieldType>
+void MapField<Derived, Key, T, kKeyFieldType,
+              kValueFieldType>::UnsafeShallowSwap(MapFieldBase* other) {
+  InternalSwap(down_cast<MapField*>(other));
+}
+
+template <typename Derived, typename Key, typename T,
+          WireFormatLite::FieldType kKeyFieldType,
+          WireFormatLite::FieldType kValueFieldType>
 void MapField<Derived, Key, T, kKeyFieldType, kValueFieldType>::InternalSwap(
     MapField* other) {
   MapFieldBase::InternalSwap(other);
diff --git a/src/google/protobuf/message.cc b/src/google/protobuf/message.cc
index 7228429..744bbc6 100644
--- a/src/google/protobuf/message.cc
+++ b/src/google/protobuf/message.cc
@@ -79,15 +79,15 @@
 using internal::WireFormatLite;
 
 void Message::MergeFrom(const Message& from) {
-  const Descriptor* descriptor = GetDescriptor();
-  GOOGLE_CHECK_EQ(from.GetDescriptor(), descriptor)
-      << ": Tried to merge from a message with a different type.  "
-         "to: "
-      << descriptor->full_name()
-      << ", "
-         "from: "
-      << from.GetDescriptor()->full_name();
-  ReflectionOps::Merge(from, this);
+  auto* class_to = GetClassData();
+  auto* class_from = from.GetClassData();
+  auto* merge_to_from = class_to ? class_to->merge_to_from : nullptr;
+  if (class_to == nullptr || class_to != class_from) {
+    merge_to_from = [](Message* to, const Message& from) {
+      ReflectionOps::Merge(from, to);
+    };
+  }
+  merge_to_from(this, from);
 }
 
 void Message::CheckTypeAndMergeFrom(const MessageLite& other) {
@@ -95,15 +95,40 @@
 }
 
 void Message::CopyFrom(const Message& from) {
-  const Descriptor* descriptor = GetDescriptor();
-  GOOGLE_CHECK_EQ(from.GetDescriptor(), descriptor)
-      << ": Tried to copy from a message with a different type. "
-         "to: "
-      << descriptor->full_name()
-      << ", "
-         "from: "
-      << from.GetDescriptor()->full_name();
-  ReflectionOps::Copy(from, this);
+  if (&from == this) return;
+
+  auto* class_to = GetClassData();
+  auto* class_from = from.GetClassData();
+  auto* copy_to_from = class_to ? class_to->copy_to_from : nullptr;
+
+  if (class_to == nullptr || class_to != class_from) {
+    const Descriptor* descriptor = GetDescriptor();
+    GOOGLE_CHECK_EQ(from.GetDescriptor(), descriptor)
+        << ": Tried to copy from a message with a different type. "
+           "to: "
+        << descriptor->full_name()
+        << ", "
+           "from: "
+        << from.GetDescriptor()->full_name();
+    copy_to_from = [](Message* to, const Message& from) {
+      ReflectionOps::Copy(from, to);
+    };
+  }
+  copy_to_from(this, from);
+}
+
+void Message::CopyWithSizeCheck(Message* to, const Message& from) {
+#ifndef NDEBUG
+  size_t from_size = from.ByteSizeLong();
+#endif
+  to->Clear();
+#ifndef NDEBUG
+  GOOGLE_CHECK_EQ(from_size, from.ByteSizeLong())
+      << "Source of CopyFrom changed when clearing target.  Either "
+         "source is a nested message in target (not allowed), or "
+         "another thread is modifying the source.";
+#endif
+  to->GetClassData()->merge_to_from(to, from);
 }
 
 std::string Message::GetTypeName() const {
diff --git a/src/google/protobuf/message.h b/src/google/protobuf/message.h
index 068324b..df8e895 100644
--- a/src/google/protobuf/message.h
+++ b/src/google/protobuf/message.h
@@ -144,6 +144,7 @@
 // Defined in other files.
 class AssignDescriptorsHelper;
 class DynamicMessageFactory;
+class GeneratedMessageReflectionTestHelper;
 class MapKey;
 class MapValueConstRef;
 class MapValueRef;
@@ -153,6 +154,7 @@
 namespace internal {
 struct DescriptorTable;
 class MapFieldBase;
+class SwapFieldHelper;
 }
 class UnknownFieldSet;  // unknown_field_set.h
 namespace io {
@@ -163,6 +165,7 @@
 }  // namespace io
 namespace python {
 class MapReflectionFriend;  // scalar_map_container.h
+class MessageReflectionFriend;
 }
 namespace expr {
 class CelMapReflectionFriend;  // field_backed_map_impl.cc
@@ -363,7 +366,28 @@
   // to implement GetDescriptor() and GetReflection() above.
   virtual Metadata GetMetadata() const = 0;
 
-  inline explicit Message(Arena* arena) : MessageLite(arena) {}
+  struct ClassData {
+    // Note: The order of arguments (to, then from) is chosen so that the ABI
+    // of this function is the same as the CopyFrom method.  That is, the
+    // hidden "this" parameter comes first.
+    void (*copy_to_from)(Message* to, const Message& from_msg);
+    void (*merge_to_from)(Message* to, const Message& from_msg);
+  };
+  // GetClassData() returns a pointer to a ClassData struct which
+  // exists in global memory and is unique to each subclass.  This uniqueness
+  // property is used in order to quickly determine whether two messages are
+  // of the same type.
+  // TODO(jorg): change to pure virtual
+  virtual const ClassData* GetClassData() const { return nullptr; }
+
+  // CopyWithSizeCheck calls Clear() and then MergeFrom(), and in debug
+  // builds, checks that calling Clear() on the destination message doesn't
+  // alter the size of the source.  It assumes the messages are known to be
+  // of the same type, and thus uses GetClassData().
+  static void CopyWithSizeCheck(Message* to, const Message& from);
+
+  inline explicit Message(Arena* arena, bool is_message_owned = false)
+      : MessageLite(arena, is_message_owned) {}
 
 
  protected:
@@ -476,7 +500,7 @@
   void RemoveLast(Message* message, const FieldDescriptor* field) const;
   // Removes the last element of a repeated message field, and returns the
   // pointer to the caller.  Caller takes ownership of the returned pointer.
-  PROTOBUF_FUTURE_MUST_USE_RESULT Message* ReleaseLast(
+  PROTOBUF_MUST_USE_RESULT Message* ReleaseLast(
       Message* message, const FieldDescriptor* field) const;
 
   // Swap the complete contents of two messages.
@@ -613,7 +637,7 @@
   // If the field existed (HasField() is true), then the returned pointer will
   // be the same as the pointer returned by MutableMessage().
   // This function has the same effect as ClearField().
-  PROTOBUF_FUTURE_MUST_USE_RESULT Message* ReleaseMessage(
+  PROTOBUF_MUST_USE_RESULT Message* ReleaseMessage(
       Message* message, const FieldDescriptor* field,
       MessageFactory* factory = nullptr) const;
 
@@ -986,7 +1010,9 @@
   friend class ::PROTOBUF_NAMESPACE_ID::MessageLayoutInspector;
   friend class ::PROTOBUF_NAMESPACE_ID::AssignDescriptorsHelper;
   friend class DynamicMessageFactory;
+  friend class GeneratedMessageReflectionTestHelper;
   friend class python::MapReflectionFriend;
+  friend class python::MessageReflectionFriend;
   friend class util::MessageDifferencer;
 #define GOOGLE_PROTOBUF_HAS_CEL_MAP_REFLECTION_FRIEND
   friend class expr::CelMapReflectionFriend;
@@ -994,6 +1020,7 @@
   friend class internal::MapKeySorter;
   friend class internal::WireFormat;
   friend class internal::ReflectionOps;
+  friend class internal::SwapFieldHelper;
   // Needed for implementing text format for map.
   friend class internal::MapFieldPrinterHelper;
 
@@ -1098,14 +1125,33 @@
   inline void SwapBit(Message* message1, Message* message2,
                       const FieldDescriptor* field) const;
 
+  // Shallow-swap fields listed in fields vector of two messages. It is the
+  // caller's responsibility to make sure shallow swap is safe.
+  void UnsafeShallowSwapFields(
+      Message* message1, Message* message2,
+      const std::vector<const FieldDescriptor*>& fields) const;
+
   // This function only swaps the field. Should swap corresponding has_bit
   // before or after using this function.
   void SwapField(Message* message1, Message* message2,
                  const FieldDescriptor* field) const;
 
+  // Unsafe but shallow version of SwapField.
+  void UnsafeShallowSwapField(Message* message1, Message* message2,
+                              const FieldDescriptor* field) const;
+
+  template <bool unsafe_shallow_swap>
+  void SwapFieldsImpl(Message* message1, Message* message2,
+                      const std::vector<const FieldDescriptor*>& fields) const;
+
   void SwapOneofField(Message* message1, Message* message2,
                       const OneofDescriptor* oneof_descriptor) const;
 
+  // Unsafe but shallow version of SwapOneofField.
+  void UnsafeShallowSwapOneofField(
+      Message* message1, Message* message2,
+      const OneofDescriptor* oneof_descriptor) const;
+
   inline bool HasOneofField(const Message& message,
                             const FieldDescriptor* field) const;
   inline void SetOneofCase(Message* message,
diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h
index f753e65..f82bd0c 100644
--- a/src/google/protobuf/message_lite.h
+++ b/src/google/protobuf/message_lite.h
@@ -78,6 +78,8 @@
 }  // namespace io
 namespace internal {
 
+class SwapFieldHelper;
+
 // Tag type used to invoke the constinit constructor overload of some classes.
 // Such constructors are internal implementation details of the library.
 struct ConstantInitialized {
@@ -90,6 +92,7 @@
 class ExtensionSet;
 class LazyField;
 class RepeatedPtrFieldBase;
+class TcParserBase;
 class WireFormatLite;
 class WeakFieldMap;
 
@@ -472,14 +475,15 @@
     return Arena::CreateMaybeMessage<T>(arena);
   }
 
-  inline explicit MessageLite(Arena* arena) : _internal_metadata_(arena) {}
+  inline explicit MessageLite(Arena* arena, bool is_message_owned = false)
+      : _internal_metadata_(arena, is_message_owned) {}
 
   // Returns the arena, if any, that directly owns this message and its internal
   // memory (Arena::Own is different in that the arena doesn't directly own the
   // internal memory). This method is used in proto's implementation for
   // swapping, moving and setting allocated, for deciding whether the ownership
   // of this message or its internal memory could be changed.
-  Arena* GetOwningArena() const { return _internal_metadata_.arena(); }
+  Arena* GetOwningArena() const { return _internal_metadata_.owning_arena(); }
 
   // Returns the arena, used for allocating internal objects(e.g., child
   // messages, etc), or owning incoming objects (e.g., set allocated).
@@ -524,6 +528,8 @@
   friend class Reflection;
   friend class internal::ExtensionSet;
   friend class internal::LazyField;
+  friend class internal::SwapFieldHelper;
+  friend class internal::TcParserBase;
   friend class internal::WeakFieldMap;
   friend class internal::WireFormatLite;
 
diff --git a/src/google/protobuf/metadata_lite.h b/src/google/protobuf/metadata_lite.h
index ad5710c..0b90f28 100644
--- a/src/google/protobuf/metadata_lite.h
+++ b/src/google/protobuf/metadata_lite.h
@@ -61,8 +61,19 @@
 // allocation and bit 1 == 1 to indicate heap allocation.
 class InternalMetadata {
  public:
-  constexpr InternalMetadata() : ptr_(nullptr) {}
-  explicit InternalMetadata(Arena* arena) : ptr_(arena) {}
+  constexpr InternalMetadata() : ptr_(0) {}
+  explicit InternalMetadata(Arena* arena, bool is_message_owned = false)
+      : ptr_(is_message_owned
+                 ? reinterpret_cast<intptr_t>(arena) | kMessageOwnedArenaTagMask
+                 : reinterpret_cast<intptr_t>(arena)) {
+    GOOGLE_DCHECK(!is_message_owned || arena != nullptr);
+  }
+
+  ~InternalMetadata() {
+    if (HasMessageOwnedArenaTag()) {
+      delete arena();
+    }
+  }
 
   template <typename T>
   void Delete() {
@@ -72,6 +83,10 @@
     }
   }
 
+  PROTOBUF_NDEBUG_INLINE Arena* owning_arena() const {
+    return HasMessageOwnedArenaTag() ? nullptr : arena();
+  }
+
   PROTOBUF_NDEBUG_INLINE Arena* arena() const {
     if (PROTOBUF_PREDICT_FALSE(have_unknown_fields())) {
       return PtrValue<ContainerBase>()->arena;
@@ -81,10 +96,12 @@
   }
 
   PROTOBUF_NDEBUG_INLINE bool have_unknown_fields() const {
-    return PtrTag() == kTagContainer;
+    return HasUnknownFieldsTag();
   }
 
-  PROTOBUF_NDEBUG_INLINE void* raw_arena_ptr() const { return ptr_; }
+  PROTOBUF_NDEBUG_INLINE void* raw_arena_ptr() const {
+    return reinterpret_cast<void*>(ptr_);
+  }
 
   template <typename T>
   PROTOBUF_NDEBUG_INLINE const T& unknown_fields(
@@ -137,27 +154,26 @@
   }
 
  private:
-  void* ptr_;
+  intptr_t ptr_;
 
   // Tagged pointer implementation.
-  enum {
-    // ptr_ is an Arena*.
-    kTagArena = 0,
-    // ptr_ is a Container*.
-    kTagContainer = 1,
-  };
-  static constexpr intptr_t kPtrTagMask = 1;
+  static constexpr intptr_t kUnknownFieldsTagMask = 1;
+  static constexpr intptr_t kMessageOwnedArenaTagMask = 2;
+  static constexpr intptr_t kPtrTagMask =
+      kUnknownFieldsTagMask | kMessageOwnedArenaTagMask;
   static constexpr intptr_t kPtrValueMask = ~kPtrTagMask;
 
   // Accessors for pointer tag and pointer value.
-  PROTOBUF_NDEBUG_INLINE int PtrTag() const {
-    return reinterpret_cast<intptr_t>(ptr_) & kPtrTagMask;
+  PROTOBUF_ALWAYS_INLINE bool HasUnknownFieldsTag() const {
+    return ptr_ & kUnknownFieldsTagMask;
+  }
+  PROTOBUF_ALWAYS_INLINE bool HasMessageOwnedArenaTag() const {
+    return ptr_ & kMessageOwnedArenaTagMask;
   }
 
   template <typename U>
   U* PtrValue() const {
-    return reinterpret_cast<U*>(reinterpret_cast<intptr_t>(ptr_) &
-                                kPtrValueMask);
+    return reinterpret_cast<U*>(ptr_ & kPtrValueMask);
   }
 
   // If ptr_'s tag is kTagContainer, it points to an instance of this struct.
@@ -181,11 +197,11 @@
   PROTOBUF_NOINLINE T* mutable_unknown_fields_slow() {
     Arena* my_arena = arena();
     Container<T>* container = Arena::Create<Container<T>>(my_arena);
+    intptr_t message_owned_arena_tag = ptr_ & kMessageOwnedArenaTagMask;
     // Two-step assignment works around a bug in clang's static analyzer:
     // https://bugs.llvm.org/show_bug.cgi?id=34198.
-    ptr_ = container;
-    ptr_ = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(ptr_) |
-                                   kTagContainer);
+    ptr_ = reinterpret_cast<intptr_t>(container);
+    ptr_ |= kUnknownFieldsTagMask | message_owned_arena_tag;
     container->arena = my_arena;
     return &(container->unknown_fields);
   }
diff --git a/src/google/protobuf/parse_context.cc b/src/google/protobuf/parse_context.cc
index e141c43..1bf5ef8 100644
--- a/src/google/protobuf/parse_context.cc
+++ b/src/google/protobuf/parse_context.cc
@@ -234,18 +234,6 @@
 }
 
 
-template <typename Tag, typename T>
-const char* EpsCopyInputStream::ReadRepeatedFixed(const char* ptr,
-                                                  Tag expected_tag,
-                                                  RepeatedField<T>* out) {
-  do {
-    out->Add(UnalignedLoad<T>(ptr));
-    ptr += sizeof(T);
-    if (PROTOBUF_PREDICT_FALSE(ptr >= limit_end_)) return ptr;
-  } while (UnalignedLoad<Tag>(ptr) == expected_tag&& ptr += sizeof(Tag));
-  return ptr;
-}
-
 template <int>
 void byteswap(void* p);
 template <>
@@ -259,44 +247,6 @@
   *static_cast<uint64*>(p) = bswap_64(*static_cast<uint64*>(p));
 }
 
-template <typename T>
-const char* EpsCopyInputStream::ReadPackedFixed(const char* ptr, int size,
-                                                RepeatedField<T>* out) {
-  int nbytes = buffer_end_ + kSlopBytes - ptr;
-  while (size > nbytes) {
-    int num = nbytes / sizeof(T);
-    int old_entries = out->size();
-    out->Reserve(old_entries + num);
-    int block_size = num * sizeof(T);
-    auto dst = out->AddNAlreadyReserved(num);
-#ifdef PROTOBUF_LITTLE_ENDIAN
-    std::memcpy(dst, ptr, block_size);
-#else
-    for (int i = 0; i < num; i++)
-      dst[i] = UnalignedLoad<T>(ptr + i * sizeof(T));
-#endif
-    size -= block_size;
-    if (limit_ <= kSlopBytes) return nullptr;
-    ptr = Next();
-    if (ptr == nullptr) return nullptr;
-    ptr += kSlopBytes - (nbytes - block_size);
-    nbytes = buffer_end_ + kSlopBytes - ptr;
-  }
-  int num = size / sizeof(T);
-  int old_entries = out->size();
-  out->Reserve(old_entries + num);
-  int block_size = num * sizeof(T);
-  auto dst = out->AddNAlreadyReserved(num);
-#ifdef PROTOBUF_LITTLE_ENDIAN
-  std::memcpy(dst, ptr, block_size);
-#else
-  for (int i = 0; i < num; i++) dst[i] = UnalignedLoad<T>(ptr + i * sizeof(T));
-#endif
-  ptr += block_size;
-  if (size != block_size) return nullptr;
-  return ptr;
-}
-
 const char* EpsCopyInputStream::InitFrom(io::ZeroCopyInputStream* zcis) {
   zcis_ = zcis;
   const void* data;
diff --git a/src/google/protobuf/parse_context.h b/src/google/protobuf/parse_context.h
index 00b07d9..14748f6 100644
--- a/src/google/protobuf/parse_context.h
+++ b/src/google/protobuf/parse_context.h
@@ -376,6 +376,7 @@
   struct Data {
     const DescriptorPool* pool = nullptr;
     MessageFactory* factory = nullptr;
+    Arena* arena = nullptr;
   };
 
   template <typename... T>
@@ -658,6 +659,56 @@
   return ptr;
 }
 
+template <typename Tag, typename T>
+const char* EpsCopyInputStream::ReadRepeatedFixed(const char* ptr,
+                                                  Tag expected_tag,
+                                                  RepeatedField<T>* out) {
+  do {
+    out->Add(UnalignedLoad<T>(ptr));
+    ptr += sizeof(T);
+    if (PROTOBUF_PREDICT_FALSE(ptr >= limit_end_)) return ptr;
+  } while (UnalignedLoad<Tag>(ptr) == expected_tag && (ptr += sizeof(Tag)));
+  return ptr;
+}
+
+template <typename T>
+const char* EpsCopyInputStream::ReadPackedFixed(const char* ptr, int size,
+                                                RepeatedField<T>* out) {
+  int nbytes = buffer_end_ + kSlopBytes - ptr;
+  while (size > nbytes) {
+    int num = nbytes / sizeof(T);
+    int old_entries = out->size();
+    out->Reserve(old_entries + num);
+    int block_size = num * sizeof(T);
+    auto dst = out->AddNAlreadyReserved(num);
+#ifdef PROTOBUF_LITTLE_ENDIAN
+    std::memcpy(dst, ptr, block_size);
+#else
+    for (int i = 0; i < num; i++)
+      dst[i] = UnalignedLoad<T>(ptr + i * sizeof(T));
+#endif
+    size -= block_size;
+    if (limit_ <= kSlopBytes) return nullptr;
+    ptr = Next();
+    if (ptr == nullptr) return nullptr;
+    ptr += kSlopBytes - (nbytes - block_size);
+    nbytes = buffer_end_ + kSlopBytes - ptr;
+  }
+  int num = size / sizeof(T);
+  int old_entries = out->size();
+  out->Reserve(old_entries + num);
+  int block_size = num * sizeof(T);
+  auto dst = out->AddNAlreadyReserved(num);
+#ifdef PROTOBUF_LITTLE_ENDIAN
+  std::memcpy(dst, ptr, block_size);
+#else
+  for (int i = 0; i < num; i++) dst[i] = UnalignedLoad<T>(ptr + i * sizeof(T));
+#endif
+  ptr += block_size;
+  if (size != block_size) return nullptr;
+  return ptr;
+}
+
 template <typename Add>
 const char* ReadPackedVarintArray(const char* ptr, const char* end, Add add) {
   while (ptr < end) {
diff --git a/src/google/protobuf/port_def.inc b/src/google/protobuf/port_def.inc
index 391fdf2..10a609b 100644
--- a/src/google/protobuf/port_def.inc
+++ b/src/google/protobuf/port_def.inc
@@ -177,6 +177,23 @@
 # define PROTOBUF_NOINLINE __declspec(noinline)
 #endif
 
+#ifdef PROTOBUF_MUSTTAIL
+#error PROTOBUF_MUSTTAIL was previously defined
+#endif
+#ifdef PROTOBUF_TAILCALL
+#error PROTOBUF_TAILCALL was previously defined
+#endif
+#if __has_cpp_attribute(clang::musttail) && !defined(_ARCH_PPC)
+#  ifndef PROTO2_OPENSOURCE
+// Compilation fails on powerpc64le: b/187985113
+#  endif
+#define PROTOBUF_MUSTTAIL [[clang::musttail]]
+#define PROTOBUF_TAILCALL true
+#else
+#define PROTOBUF_MUSTTAIL
+#define PROTOBUF_TAILCALL false
+#endif
+
 #ifdef PROTOBUF_EXCLUSIVE_LOCKS_REQUIRED
 #error PROTOBUF_EXCLUSIVE_LOCKS_REQUIRED was previously defined
 #endif
@@ -389,9 +406,12 @@
 #ifdef PROTOBUF_MUST_USE_RESULT
 #error PROTOBUF_MUST_USE_RESULT was previously defined
 #endif
-# define PROTOBUF_FUTURE_MUST_USE_RESULT
 # define PROTOBUF_MUST_USE_RESULT
 
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+#error PROTOBUF_FORCE_COPY_IN_SWAP was previously defined
+#endif
+
 #ifdef PROTOBUF_FALLTHROUGH_INTENDED
 #error PROTOBUF_FALLTHROUGH_INTENDED was previously defined
 #endif
@@ -451,6 +471,11 @@
 #define PROTOBUF_ALIGNAS(byte_alignment) alignas(byte_alignment)
 #endif
 
+#ifdef PROTOBUF_FINAL
+#error PROTOBUF_FINAL was previously defined
+#endif
+#define PROTOBUF_FINAL final
+
 #ifdef PROTOBUF_THREAD_LOCAL
 #error PROTOBUF_THREAD_LOCAL was previously defined
 #endif
@@ -470,7 +495,7 @@
 // we need to simulate the arena ownership.
 // This experiment is purely for the purpose of gathering data. All code guarded
 // by this flag is supposed to be removed after this experiment.
-// #define PROTOBUF_MESSAGE_OWNED_ARENA_EXPERIMENT
+#define PROTOBUF_MESSAGE_OWNED_ARENA_EXPERIMENT
 #ifdef PROTOBUF_CONSTINIT
 #error PROTOBUF_CONSTINIT was previously defined
 #endif
diff --git a/src/google/protobuf/port_undef.inc b/src/google/protobuf/port_undef.inc
index 82fe794..470547e 100644
--- a/src/google/protobuf/port_undef.inc
+++ b/src/google/protobuf/port_undef.inc
@@ -38,6 +38,8 @@
 #undef PROTOBUF_NAMESPACE_ID
 #undef PROTOBUF_ALWAYS_INLINE
 #undef PROTOBUF_NDEBUG_INLINE
+#undef PROTOBUF_MUSTTAIL
+#undef PROTOBUF_TAILCALL
 #undef PROTOBUF_COLD
 #undef PROTOBUF_NOINLINE
 #undef PROTOBUF_SECTION_VARIABLE
@@ -59,6 +61,7 @@
 #undef PROTOBUF_EXPORT
 #undef PROTOC_EXPORT
 #undef PROTOBUF_MUST_USE_RESULT
+#undef PROTOBUF_FORCE_COPY_IN_SWAP
 #undef PROTOBUF_NAMESPACE_OPEN
 #undef PROTOBUF_NAMESPACE_CLOSE
 #undef PROTOBUF_UNUSED
@@ -66,6 +69,7 @@
 #undef PROTOBUF_EXPORT_TEMPLATE_DECLARE
 #undef PROTOBUF_EXPORT_TEMPLATE_DEFINE
 #undef PROTOBUF_ALIGNAS
+#undef PROTOBUF_FINAL
 #undef PROTOBUF_THREAD_LOCAL
 #undef PROTOBUF_MESSAGE_OWNED_ARENA_EXPERIMENT
 #undef PROTOBUF_CONSTINIT
diff --git a/src/google/protobuf/reflection_ops.cc b/src/google/protobuf/reflection_ops.cc
index 1c521e4..5380797 100644
--- a/src/google/protobuf/reflection_ops.cc
+++ b/src/google/protobuf/reflection_ops.cc
@@ -419,8 +419,12 @@
 }
 
 void GenericSwap(Message* lhs, Message* rhs) {
+#ifndef PROTOBUF_FORCE_COPY_IN_SWAP
   GOOGLE_DCHECK(Arena::InternalHelper<Message>::GetOwningArena(lhs) !=
          Arena::InternalHelper<Message>::GetOwningArena(rhs));
+  GOOGLE_DCHECK(Arena::InternalHelper<Message>::GetOwningArena(lhs) != nullptr ||
+         Arena::InternalHelper<Message>::GetOwningArena(rhs) != nullptr);
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
   // At least one of these must have an arena, so make `rhs` point to it.
   Arena* arena = Arena::InternalHelper<Message>::GetOwningArena(rhs);
   if (arena == nullptr) {
@@ -430,12 +434,17 @@
 
   // Improve efficiency by placing the temporary on an arena so that messages
   // are copied twice rather than three times.
-  GOOGLE_DCHECK(arena != nullptr);
   Message* tmp = rhs->New(arena);
   tmp->CheckTypeAndMergeFrom(*lhs);
   lhs->Clear();
   lhs->CheckTypeAndMergeFrom(*rhs);
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  rhs->Clear();
+  rhs->CheckTypeAndMergeFrom(*tmp);
+  if (arena == nullptr) delete tmp;
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
   rhs->GetReflection()->Swap(tmp, rhs);
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
 }
 
 }  // namespace internal
diff --git a/src/google/protobuf/repeated_field.h b/src/google/protobuf/repeated_field.h
index 57bc7ee..a32f2d8 100644
--- a/src/google/protobuf/repeated_field.h
+++ b/src/google/protobuf/repeated_field.h
@@ -85,6 +85,7 @@
 namespace internal {
 
 class MergePartialFromCodedStreamHelper;
+class SwapFieldHelper;
 
 // kRepeatedFieldLowerClampLimit is the smallest size that will be allocated
 // when growing a repeated field.
@@ -686,7 +687,7 @@
   void UnsafeArenaAddAllocated(typename TypeHandler::Type* value);
 
   template <typename TypeHandler>
-  PROTOBUF_FUTURE_MUST_USE_RESULT typename TypeHandler::Type* ReleaseLast() {
+  PROTOBUF_MUST_USE_RESULT typename TypeHandler::Type* ReleaseLast() {
     typename TypeImplementsMergeBehavior<typename TypeHandler::Type>::type t;
     return ReleaseLastInternal<TypeHandler>(t);
   }
@@ -700,7 +701,7 @@
   template <typename TypeHandler>
   void AddCleared(typename TypeHandler::Type* value);
   template <typename TypeHandler>
-  PROTOBUF_FUTURE_MUST_USE_RESULT typename TypeHandler::Type* ReleaseCleared();
+  PROTOBUF_MUST_USE_RESULT typename TypeHandler::Type* ReleaseCleared();
 
   template <typename TypeHandler>
   void AddAllocatedInternal(typename TypeHandler::Type* value, std::true_type);
@@ -786,6 +787,7 @@
   // reinterpreting pointers as being to Message instead of a specific Message
   // subclass.
   friend class ::PROTOBUF_NAMESPACE_ID::Reflection;
+  friend class ::PROTOBUF_NAMESPACE_ID::internal::SwapFieldHelper;
 
   // ExtensionSet stores repeated message extensions as
   // RepeatedPtrField<MessageLite>, but non-lite ExtensionSets need to implement
@@ -1071,7 +1073,7 @@
   // If this RepeatedPtrField is on an arena, an object copy is required to pass
   // ownership back to the user (for compatible semantics). Use
   // UnsafeArenaReleaseLast() if this behavior is undesired.
-  PROTOBUF_FUTURE_MUST_USE_RESULT Element* ReleaseLast();
+  PROTOBUF_MUST_USE_RESULT Element* ReleaseLast();
 
   // Add an already-allocated object, skipping arena-ownership checks. The user
   // must guarantee that the given object is in the same arena as this
@@ -1141,7 +1143,7 @@
   //
   // This method cannot be called when the repeated field is on an arena; doing
   // so will trigger a GOOGLE_DCHECK-failure.
-  PROTOBUF_FUTURE_MUST_USE_RESULT Element* ReleaseCleared();
+  PROTOBUF_MUST_USE_RESULT Element* ReleaseCleared();
 
   // Removes the element referenced by position.
   //
@@ -1497,7 +1499,11 @@
 template <typename Element>
 void RepeatedField<Element>::Swap(RepeatedField* other) {
   if (this == other) return;
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  if (GetArena() != nullptr && GetArena() == other->GetArena()) {
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
   if (GetArena() == other->GetArena()) {
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
     InternalSwap(other);
   } else {
     RepeatedField<Element> temp(other->GetArena());
@@ -1698,7 +1704,11 @@
 
 template <typename TypeHandler>
 inline void RepeatedPtrFieldBase::Swap(RepeatedPtrFieldBase* other) {
-  if (other->GetArena() == GetArena()) {
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  if (GetArena() != nullptr && GetArena() == other->GetArena()) {
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
+  if (GetArena() == other->GetArena()) {
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
     InternalSwap(other);
   } else {
     SwapFallback<TypeHandler>(other);
@@ -1707,7 +1717,11 @@
 
 template <typename TypeHandler>
 void RepeatedPtrFieldBase::SwapFallback(RepeatedPtrFieldBase* other) {
+#ifdef PROTOBUF_FORCE_COPY_IN_SWAP
+  GOOGLE_DCHECK(GetArena() == nullptr || other->GetArena() != GetArena());
+#else   // PROTOBUF_FORCE_COPY_IN_SWAP
   GOOGLE_DCHECK(other->GetArena() != GetArena());
+#endif  // !PROTOBUF_FORCE_COPY_IN_SWAP
 
   // Copy semantics in this case. We try to improve efficiency by placing the
   // temporary on |other|'s arena so that messages are copied twice rather than
@@ -1956,6 +1970,9 @@
     // Pass value_arena and my_arena to avoid duplicate virtual call (value) or
     // load (mine).
     typename TypeHandler::Type* value, Arena* value_arena, Arena* my_arena) {
+#ifdef PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
+  GOOGLE_DCHECK(value_arena == nullptr || value_arena == my_arena);
+#endif  // PROTOBUF_INTERNAL_USE_MUST_USE_RESULT
   // Ensure that either the value is in the same arena, or if not, we do the
   // appropriate thing: Own() it (if it's on heap and we're in an arena) or copy
   // it to our arena/heap (otherwise).
diff --git a/src/google/protobuf/repeated_field_unittest.cc b/src/google/protobuf/repeated_field_unittest.cc
index 0201be6..46b9e6d 100644
--- a/src/google/protobuf/repeated_field_unittest.cc
+++ b/src/google/protobuf/repeated_field_unittest.cc
@@ -2107,39 +2107,35 @@
 TEST_F(RepeatedFieldInsertionIteratorsTest,
        UnsafeArenaAllocatedRepeatedPtrFieldWithStringIntData) {
   std::vector<Nested*> data;
-  TestAllTypes goldenproto;
+  Arena arena;
+  auto* goldenproto = Arena::CreateMessage<TestAllTypes>(&arena);
   for (int i = 0; i < 10; ++i) {
-    Nested* new_data = new Nested;
+    auto* new_data = goldenproto->add_repeated_nested_message();
     new_data->set_bb(i);
     data.push_back(new_data);
-
-    new_data = goldenproto.add_repeated_nested_message();
-    new_data->set_bb(i);
   }
-  TestAllTypes testproto;
+  auto* testproto = Arena::CreateMessage<TestAllTypes>(&arena);
   std::copy(data.begin(), data.end(),
             UnsafeArenaAllocatedRepeatedPtrFieldBackInserter(
-                testproto.mutable_repeated_nested_message()));
-  EXPECT_EQ(testproto.DebugString(), goldenproto.DebugString());
+                testproto->mutable_repeated_nested_message()));
+  EXPECT_EQ(testproto->DebugString(), goldenproto->DebugString());
 }
 
 TEST_F(RepeatedFieldInsertionIteratorsTest,
        UnsafeArenaAllocatedRepeatedPtrFieldWithString) {
   std::vector<std::string*> data;
-  TestAllTypes goldenproto;
+  Arena arena;
+  auto* goldenproto = Arena::CreateMessage<TestAllTypes>(&arena);
   for (int i = 0; i < 10; ++i) {
-    std::string* new_data = new std::string;
+    auto* new_data = goldenproto->add_repeated_string();
     *new_data = "name-" + StrCat(i);
     data.push_back(new_data);
-
-    new_data = goldenproto.add_repeated_string();
-    *new_data = "name-" + StrCat(i);
   }
-  TestAllTypes testproto;
+  auto* testproto = Arena::CreateMessage<TestAllTypes>(&arena);
   std::copy(data.begin(), data.end(),
             UnsafeArenaAllocatedRepeatedPtrFieldBackInserter(
-                testproto.mutable_repeated_string()));
-  EXPECT_EQ(testproto.DebugString(), goldenproto.DebugString());
+                testproto->mutable_repeated_string()));
+  EXPECT_EQ(testproto->DebugString(), goldenproto->DebugString());
 }
 
 TEST_F(RepeatedFieldInsertionIteratorsTest, MoveStrings) {
diff --git a/src/google/protobuf/source_context.pb.cc b/src/google/protobuf/source_context.pb.cc
index 019e045..7363c3d 100644
--- a/src/google/protobuf/source_context.pb.cc
+++ b/src/google/protobuf/source_context.pb.cc
@@ -79,10 +79,13 @@
  public:
 };
 
-SourceContext::SourceContext(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+SourceContext::SourceContext(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.SourceContext)
 }
 SourceContext::SourceContext(const SourceContext& from)
@@ -96,17 +99,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.SourceContext)
 }
 
-void SourceContext::SharedCtor() {
+inline void SourceContext::SharedCtor() {
 file_name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
 
 SourceContext::~SourceContext() {
   // @@protoc_insertion_point(destructor:google.protobuf.SourceContext)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void SourceContext::SharedDtor() {
+inline void SourceContext::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   file_name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -217,38 +221,29 @@
   return total_size;
 }
 
-void SourceContext::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.SourceContext)
-  GOOGLE_DCHECK_NE(&from, this);
-  const SourceContext* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<SourceContext>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.SourceContext)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.SourceContext)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData SourceContext::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    SourceContext::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*SourceContext::GetClassData() const { return &_class_data_; }
+
+void SourceContext::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<SourceContext *>(to)->MergeFrom(
+      static_cast<const SourceContext &>(from));
 }
 
+
 void SourceContext::MergeFrom(const SourceContext& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.SourceContext)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (!from.file_name().empty()) {
     _internal_set_file_name(from._internal_file_name());
   }
-}
-
-void SourceContext::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.SourceContext)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void SourceContext::CopyFrom(const SourceContext& from) {
diff --git a/src/google/protobuf/source_context.pb.h b/src/google/protobuf/source_context.pb.h
index cf2999e..1856327 100644
--- a/src/google/protobuf/source_context.pb.h
+++ b/src/google/protobuf/source_context.pb.h
@@ -137,10 +137,13 @@
   SourceContext* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<SourceContext>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const SourceContext& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const SourceContext& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -160,12 +163,16 @@
     return "google.protobuf.SourceContext";
   }
   protected:
-  explicit SourceContext(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit SourceContext(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -181,7 +188,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_file_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_file_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_file_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_file_name();
   void set_allocated_file_name(std::string* file_name);
   private:
   const std::string& _internal_file_name() const;
@@ -227,8 +234,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.SourceContext.file_name)
 }
 inline std::string* SourceContext::mutable_file_name() {
+  std::string* _s = _internal_mutable_file_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.SourceContext.file_name)
-  return _internal_mutable_file_name();
+  return _s;
 }
 inline const std::string& SourceContext::_internal_file_name() const {
   return file_name_.Get();
diff --git a/src/google/protobuf/struct.pb.cc b/src/google/protobuf/struct.pb.cc
index 960b29c..61a93a6 100644
--- a/src/google/protobuf/struct.pb.cc
+++ b/src/google/protobuf/struct.pb.cc
@@ -177,11 +177,6 @@
       &descriptor_table_google_2fprotobuf_2fstruct_2eproto_getter, &descriptor_table_google_2fprotobuf_2fstruct_2eproto_once,
       file_level_metadata_google_2fprotobuf_2fstruct_2eproto[0]);
 }
-void Struct_FieldsEntry_DoNotUse::MergeFrom(
-    const ::PROTOBUF_NAMESPACE_ID::Message& other) {
-  ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom(other);
-}
-
 
 // ===================================================================
 
@@ -189,11 +184,14 @@
  public:
 };
 
-Struct::Struct(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Struct::Struct(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   fields_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Struct)
 }
 Struct::Struct(const Struct& from)
@@ -203,16 +201,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Struct)
 }
 
-void Struct::SharedCtor() {
+inline void Struct::SharedCtor() {
 }
 
 Struct::~Struct() {
   // @@protoc_insertion_point(destructor:google.protobuf.Struct)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Struct::SharedDtor() {
+inline void Struct::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -363,36 +362,27 @@
   return total_size;
 }
 
-void Struct::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Struct)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Struct* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Struct>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Struct)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Struct)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Struct::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Struct::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Struct::GetClassData() const { return &_class_data_; }
+
+void Struct::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Struct *>(to)->MergeFrom(
+      static_cast<const Struct &>(from));
 }
 
+
 void Struct::MergeFrom(const Struct& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Struct)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   fields_.MergeFrom(from.fields_);
-}
-
-void Struct::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Struct)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Struct::CopyFrom(const Struct& from) {
@@ -464,10 +454,13 @@
   }
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Value.list_value)
 }
-Value::Value(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Value::Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Value)
 }
 Value::Value(const Value& from)
@@ -506,17 +499,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Value)
 }
 
-void Value::SharedCtor() {
+inline void Value::SharedCtor() {
 clear_has_kind();
 }
 
 Value::~Value() {
   // @@protoc_insertion_point(destructor:google.protobuf.Value)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Value::SharedDtor() {
+inline void Value::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   if (has_kind()) {
     clear_kind();
@@ -774,25 +768,22 @@
   return total_size;
 }
 
-void Value::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Value)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Value* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Value>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Value)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Value)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Value::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Value::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Value::GetClassData() const { return &_class_data_; }
+
+void Value::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Value *>(to)->MergeFrom(
+      static_cast<const Value &>(from));
 }
 
+
 void Value::MergeFrom(const Value& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Value)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -825,13 +816,7 @@
       break;
     }
   }
-}
-
-void Value::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Value)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Value::CopyFrom(const Value& from) {
@@ -864,11 +849,14 @@
  public:
 };
 
-ListValue::ListValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+ListValue::ListValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   values_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ListValue)
 }
 ListValue::ListValue(const ListValue& from)
@@ -878,16 +866,17 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ListValue)
 }
 
-void ListValue::SharedCtor() {
+inline void ListValue::SharedCtor() {
 }
 
 ListValue::~ListValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.ListValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void ListValue::SharedDtor() {
+inline void ListValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -998,36 +987,27 @@
   return total_size;
 }
 
-void ListValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ListValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const ListValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<ListValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ListValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ListValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData ListValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    ListValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*ListValue::GetClassData() const { return &_class_data_; }
+
+void ListValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<ListValue *>(to)->MergeFrom(
+      static_cast<const ListValue &>(from));
 }
 
+
 void ListValue::MergeFrom(const ListValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ListValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   values_.MergeFrom(from.values_);
-}
-
-void ListValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ListValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void ListValue::CopyFrom(const ListValue& from) {
diff --git a/src/google/protobuf/struct.pb.h b/src/google/protobuf/struct.pb.h
index 0fec29c..9125c59 100644
--- a/src/google/protobuf/struct.pb.h
+++ b/src/google/protobuf/struct.pb.h
@@ -124,7 +124,7 @@
     return ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::VerifyUtf8String(s->data(), static_cast<int>(s->size()), ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::PARSE, "google.protobuf.Struct.FieldsEntry.key");
  }
   static bool ValidateValue(void*) { return true; }
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& other) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 };
 
@@ -202,10 +202,13 @@
   Struct* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Struct>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Struct& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Struct& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -225,12 +228,16 @@
     return "google.protobuf.Struct";
   }
   protected:
-  explicit Struct(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Struct(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -357,10 +364,13 @@
   Value* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Value>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Value& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Value& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -380,12 +390,16 @@
     return "google.protobuf.Value";
   }
   protected:
-  explicit Value(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -436,7 +450,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_string_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_string_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_string_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_string_value();
   void set_allocated_string_value(std::string* string_value);
   private:
   const std::string& _internal_string_value() const;
@@ -464,7 +478,7 @@
   public:
   void clear_struct_value();
   const PROTOBUF_NAMESPACE_ID::Struct& struct_value() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::Struct* release_struct_value();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::Struct* release_struct_value();
   PROTOBUF_NAMESPACE_ID::Struct* mutable_struct_value();
   void set_allocated_struct_value(PROTOBUF_NAMESPACE_ID::Struct* struct_value);
   private:
@@ -482,7 +496,7 @@
   public:
   void clear_list_value();
   const PROTOBUF_NAMESPACE_ID::ListValue& list_value() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::ListValue* release_list_value();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::ListValue* release_list_value();
   PROTOBUF_NAMESPACE_ID::ListValue* mutable_list_value();
   void set_allocated_list_value(PROTOBUF_NAMESPACE_ID::ListValue* list_value);
   private:
@@ -600,10 +614,13 @@
   ListValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<ListValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const ListValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const ListValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -623,12 +640,16 @@
     return "google.protobuf.ListValue";
   }
   protected:
-  explicit ListValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit ListValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -747,8 +768,8 @@
   kind_.null_value_ = value;
 }
 inline void Value::set_null_value(PROTOBUF_NAMESPACE_ID::NullValue value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.Value.null_value)
   _internal_set_null_value(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.Value.null_value)
 }
 
 // double number_value = 2;
@@ -820,8 +841,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Value.string_value)
 }
 inline std::string* Value::mutable_string_value() {
+  std::string* _s = _internal_mutable_string_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Value.string_value)
-  return _internal_mutable_string_value();
+  return _s;
 }
 inline const std::string& Value::_internal_string_value() const {
   if (_internal_has_string_value()) {
@@ -977,8 +999,9 @@
   return kind_.struct_value_;
 }
 inline PROTOBUF_NAMESPACE_ID::Struct* Value::mutable_struct_value() {
+  PROTOBUF_NAMESPACE_ID::Struct* _msg = _internal_mutable_struct_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Value.struct_value)
-  return _internal_mutable_struct_value();
+  return _msg;
 }
 
 // .google.protobuf.ListValue list_value = 6;
@@ -1050,8 +1073,9 @@
   return kind_.list_value_;
 }
 inline PROTOBUF_NAMESPACE_ID::ListValue* Value::mutable_list_value() {
+  PROTOBUF_NAMESPACE_ID::ListValue* _msg = _internal_mutable_list_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Value.list_value)
-  return _internal_mutable_list_value();
+  return _msg;
 }
 
 inline bool Value::has_kind() const {
@@ -1097,8 +1121,9 @@
   return values_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Value* ListValue::add_values() {
+  PROTOBUF_NAMESPACE_ID::Value* _add = _internal_add_values();
   // @@protoc_insertion_point(field_add:google.protobuf.ListValue.values)
-  return _internal_add_values();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Value >&
 ListValue::values() const {
diff --git a/src/google/protobuf/test_util.h b/src/google/protobuf/test_util.h
index de48c1a..819f6d8 100644
--- a/src/google/protobuf/test_util.h
+++ b/src/google/protobuf/test_util.h
@@ -1212,7 +1212,8 @@
         break;
       case NOT_NULL:
         EXPECT_TRUE(released != nullptr);
-        if (message->GetArena() == nullptr) {
+        if (Arena::InternalHelper<Message>::GetArenaForAllocation(message) ==
+            nullptr) {
           // released message must be same as sub_message if source message is
           // not on arena.
           EXPECT_EQ(&sub_message, released);
diff --git a/src/google/protobuf/timestamp.pb.cc b/src/google/protobuf/timestamp.pb.cc
index d83037e..8441f47 100644
--- a/src/google/protobuf/timestamp.pb.cc
+++ b/src/google/protobuf/timestamp.pb.cc
@@ -81,10 +81,13 @@
  public:
 };
 
-Timestamp::Timestamp(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Timestamp::Timestamp(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Timestamp)
 }
 Timestamp::Timestamp(const Timestamp& from)
@@ -96,7 +99,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Timestamp)
 }
 
-void Timestamp::SharedCtor() {
+inline void Timestamp::SharedCtor() {
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&seconds_) - reinterpret_cast<char*>(this)),
     0, static_cast<size_t>(reinterpret_cast<char*>(&nanos_) -
@@ -105,11 +108,12 @@
 
 Timestamp::~Timestamp() {
   // @@protoc_insertion_point(destructor:google.protobuf.Timestamp)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Timestamp::SharedDtor() {
+inline void Timestamp::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -235,25 +239,22 @@
   return total_size;
 }
 
-void Timestamp::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Timestamp)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Timestamp* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Timestamp>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Timestamp)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Timestamp)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Timestamp::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Timestamp::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Timestamp::GetClassData() const { return &_class_data_; }
+
+void Timestamp::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Timestamp *>(to)->MergeFrom(
+      static_cast<const Timestamp &>(from));
 }
 
+
 void Timestamp::MergeFrom(const Timestamp& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Timestamp)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -263,13 +264,7 @@
   if (from.nanos() != 0) {
     _internal_set_nanos(from._internal_nanos());
   }
-}
-
-void Timestamp::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Timestamp)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Timestamp::CopyFrom(const Timestamp& from) {
diff --git a/src/google/protobuf/timestamp.pb.h b/src/google/protobuf/timestamp.pb.h
index 3acaca9..ac3b6e9 100644
--- a/src/google/protobuf/timestamp.pb.h
+++ b/src/google/protobuf/timestamp.pb.h
@@ -137,10 +137,13 @@
   Timestamp* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Timestamp>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Timestamp& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Timestamp& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -160,12 +163,16 @@
     return "google.protobuf.Timestamp";
   }
   protected:
-  explicit Timestamp(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Timestamp(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
diff --git a/src/google/protobuf/type.pb.cc b/src/google/protobuf/type.pb.cc
index 8120721..04b2b5f 100644
--- a/src/google/protobuf/type.pb.cc
+++ b/src/google/protobuf/type.pb.cc
@@ -348,13 +348,16 @@
   }
   source_context_ = nullptr;
 }
-Type::Type(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Type::Type(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   fields_(arena),
   oneofs_(arena),
   options_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Type)
 }
 Type::Type(const Type& from)
@@ -377,7 +380,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Type)
 }
 
-void Type::SharedCtor() {
+inline void Type::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&source_context_) - reinterpret_cast<char*>(this)),
@@ -387,11 +390,12 @@
 
 Type::~Type() {
   // @@protoc_insertion_point(destructor:google.protobuf.Type)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Type::SharedDtor() {
+inline void Type::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete source_context_;
@@ -640,25 +644,22 @@
   return total_size;
 }
 
-void Type::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Type)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Type* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Type>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Type)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Type)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Type::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Type::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Type::GetClassData() const { return &_class_data_; }
+
+void Type::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Type *>(to)->MergeFrom(
+      static_cast<const Type &>(from));
 }
 
+
 void Type::MergeFrom(const Type& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Type)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -674,13 +675,7 @@
   if (from.syntax() != 0) {
     _internal_set_syntax(from._internal_syntax());
   }
-}
-
-void Type::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Type)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Type::CopyFrom(const Type& from) {
@@ -725,11 +720,14 @@
  public:
 };
 
-Field::Field(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Field::Field(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   options_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Field)
 }
 Field::Field(const Field& from)
@@ -762,7 +760,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Field)
 }
 
-void Field::SharedCtor() {
+inline void Field::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 type_url_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 json_name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -775,11 +773,12 @@
 
 Field::~Field() {
   // @@protoc_insertion_point(destructor:google.protobuf.Field)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Field::SharedDtor() {
+inline void Field::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   type_url_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
@@ -1105,25 +1104,22 @@
   return total_size;
 }
 
-void Field::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Field)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Field* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Field>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Field)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Field)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Field::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Field::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Field::GetClassData() const { return &_class_data_; }
+
+void Field::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Field *>(to)->MergeFrom(
+      static_cast<const Field &>(from));
 }
 
+
 void Field::MergeFrom(const Field& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Field)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -1155,13 +1151,7 @@
   if (from.packed() != 0) {
     _internal_set_packed(from._internal_packed());
   }
-}
-
-void Field::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Field)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Field::CopyFrom(const Field& from) {
@@ -1230,12 +1220,15 @@
   }
   source_context_ = nullptr;
 }
-Enum::Enum(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+Enum::Enum(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   enumvalue_(arena),
   options_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Enum)
 }
 Enum::Enum(const Enum& from)
@@ -1257,7 +1250,7 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Enum)
 }
 
-void Enum::SharedCtor() {
+inline void Enum::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&source_context_) - reinterpret_cast<char*>(this)),
@@ -1267,11 +1260,12 @@
 
 Enum::~Enum() {
   // @@protoc_insertion_point(destructor:google.protobuf.Enum)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Enum::SharedDtor() {
+inline void Enum::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete source_context_;
@@ -1487,25 +1481,22 @@
   return total_size;
 }
 
-void Enum::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Enum)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Enum* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Enum>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Enum)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Enum)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Enum::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Enum::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Enum::GetClassData() const { return &_class_data_; }
+
+void Enum::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Enum *>(to)->MergeFrom(
+      static_cast<const Enum &>(from));
 }
 
+
 void Enum::MergeFrom(const Enum& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Enum)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -1520,13 +1511,7 @@
   if (from.syntax() != 0) {
     _internal_set_syntax(from._internal_syntax());
   }
-}
-
-void Enum::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Enum)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Enum::CopyFrom(const Enum& from) {
@@ -1570,11 +1555,14 @@
  public:
 };
 
-EnumValue::EnumValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena),
+EnumValue::EnumValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned),
   options_(arena) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumValue)
 }
 EnumValue::EnumValue(const EnumValue& from)
@@ -1590,18 +1578,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumValue)
 }
 
-void EnumValue::SharedCtor() {
+inline void EnumValue::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 number_ = 0;
 }
 
 EnumValue::~EnumValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.EnumValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void EnumValue::SharedDtor() {
+inline void EnumValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -1761,25 +1750,22 @@
   return total_size;
 }
 
-void EnumValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const EnumValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<EnumValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData EnumValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    EnumValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*EnumValue::GetClassData() const { return &_class_data_; }
+
+void EnumValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<EnumValue *>(to)->MergeFrom(
+      static_cast<const EnumValue &>(from));
 }
 
+
 void EnumValue::MergeFrom(const EnumValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -1790,13 +1776,7 @@
   if (from.number() != 0) {
     _internal_set_number(from._internal_number());
   }
-}
-
-void EnumValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void EnumValue::CopyFrom(const EnumValue& from) {
@@ -1845,10 +1825,13 @@
   }
   value_ = nullptr;
 }
-Option::Option(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Option::Option(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Option)
 }
 Option::Option(const Option& from)
@@ -1867,18 +1850,19 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Option)
 }
 
-void Option::SharedCtor() {
+inline void Option::SharedCtor() {
 name_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 value_ = nullptr;
 }
 
 Option::~Option() {
   // @@protoc_insertion_point(destructor:google.protobuf.Option)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Option::SharedDtor() {
+inline void Option::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
   if (this != internal_default_instance()) delete value_;
@@ -2016,25 +2000,22 @@
   return total_size;
 }
 
-void Option::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Option)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Option* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Option>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Option)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Option)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Option::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Option::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Option::GetClassData() const { return &_class_data_; }
+
+void Option::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Option *>(to)->MergeFrom(
+      static_cast<const Option &>(from));
 }
 
+
 void Option::MergeFrom(const Option& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Option)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
@@ -2044,13 +2025,7 @@
   if (from.has_value()) {
     _internal_mutable_value()->PROTOBUF_NAMESPACE_ID::Any::MergeFrom(from._internal_value());
   }
-}
-
-void Option::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Option)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Option::CopyFrom(const Option& from) {
diff --git a/src/google/protobuf/type.pb.h b/src/google/protobuf/type.pb.h
index 3242d4b..79553b7 100644
--- a/src/google/protobuf/type.pb.h
+++ b/src/google/protobuf/type.pb.h
@@ -250,10 +250,13 @@
   Type* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Type>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Type& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Type& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -273,12 +276,16 @@
     return "google.protobuf.Type";
   }
   protected:
-  explicit Type(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Type(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -359,7 +366,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -374,7 +381,7 @@
   public:
   void clear_source_context();
   const PROTOBUF_NAMESPACE_ID::SourceContext& source_context() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceContext* release_source_context();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceContext* release_source_context();
   PROTOBUF_NAMESPACE_ID::SourceContext* mutable_source_context();
   void set_allocated_source_context(PROTOBUF_NAMESPACE_ID::SourceContext* source_context);
   private:
@@ -484,10 +491,13 @@
   Field* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Field>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Field& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Field& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -507,12 +517,16 @@
     return "google.protobuf.Field";
   }
   protected:
-  explicit Field(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Field(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -653,7 +667,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -667,7 +681,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_type_url(ArgT0&& arg0, ArgT... args);
   std::string* mutable_type_url();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_type_url();
+  PROTOBUF_MUST_USE_RESULT std::string* release_type_url();
   void set_allocated_type_url(std::string* type_url);
   private:
   const std::string& _internal_type_url() const;
@@ -681,7 +695,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_json_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_json_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_json_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_json_name();
   void set_allocated_json_name(std::string* json_name);
   private:
   const std::string& _internal_json_name() const;
@@ -695,7 +709,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_default_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_default_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_default_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_default_value();
   void set_allocated_default_value(std::string* default_value);
   private:
   const std::string& _internal_default_value() const;
@@ -842,10 +856,13 @@
   Enum* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Enum>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Enum& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Enum& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -865,12 +882,16 @@
     return "google.protobuf.Enum";
   }
   protected:
-  explicit Enum(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Enum(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -926,7 +947,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -941,7 +962,7 @@
   public:
   void clear_source_context();
   const PROTOBUF_NAMESPACE_ID::SourceContext& source_context() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceContext* release_source_context();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::SourceContext* release_source_context();
   PROTOBUF_NAMESPACE_ID::SourceContext* mutable_source_context();
   void set_allocated_source_context(PROTOBUF_NAMESPACE_ID::SourceContext* source_context);
   private:
@@ -1050,10 +1071,13 @@
   EnumValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<EnumValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const EnumValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const EnumValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1073,12 +1097,16 @@
     return "google.protobuf.EnumValue";
   }
   protected:
-  explicit EnumValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit EnumValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1114,7 +1142,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -1218,10 +1246,13 @@
   Option* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Option>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Option& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Option& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1241,12 +1272,16 @@
     return "google.protobuf.Option";
   }
   protected:
-  explicit Option(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Option(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1263,7 +1298,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_name(ArgT0&& arg0, ArgT... args);
   std::string* mutable_name();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_name();
+  PROTOBUF_MUST_USE_RESULT std::string* release_name();
   void set_allocated_name(std::string* name);
   private:
   const std::string& _internal_name() const;
@@ -1278,7 +1313,7 @@
   public:
   void clear_value();
   const PROTOBUF_NAMESPACE_ID::Any& value() const;
-  PROTOBUF_FUTURE_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::Any* release_value();
+  PROTOBUF_MUST_USE_RESULT PROTOBUF_NAMESPACE_ID::Any* release_value();
   PROTOBUF_NAMESPACE_ID::Any* mutable_value();
   void set_allocated_value(PROTOBUF_NAMESPACE_ID::Any* value);
   private:
@@ -1328,8 +1363,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Type.name)
 }
 inline std::string* Type::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Type.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Type::_internal_name() const {
   return name_.Get();
@@ -1387,8 +1423,9 @@
   return fields_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Field* Type::add_fields() {
+  PROTOBUF_NAMESPACE_ID::Field* _add = _internal_add_fields();
   // @@protoc_insertion_point(field_add:google.protobuf.Type.fields)
-  return _internal_add_fields();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Field >&
 Type::fields() const {
@@ -1407,8 +1444,9 @@
   oneofs_.Clear();
 }
 inline std::string* Type::add_oneofs() {
+  std::string* _s = _internal_add_oneofs();
   // @@protoc_insertion_point(field_add_mutable:google.protobuf.Type.oneofs)
-  return _internal_add_oneofs();
+  return _s;
 }
 inline const std::string& Type::_internal_oneofs(int index) const {
   return oneofs_.Get(index);
@@ -1422,12 +1460,12 @@
   return oneofs_.Mutable(index);
 }
 inline void Type::set_oneofs(int index, const std::string& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.Type.oneofs)
   oneofs_.Mutable(index)->assign(value);
+  // @@protoc_insertion_point(field_set:google.protobuf.Type.oneofs)
 }
 inline void Type::set_oneofs(int index, std::string&& value) {
-  // @@protoc_insertion_point(field_set:google.protobuf.Type.oneofs)
   oneofs_.Mutable(index)->assign(std::move(value));
+  // @@protoc_insertion_point(field_set:google.protobuf.Type.oneofs)
 }
 inline void Type::set_oneofs(int index, const char* value) {
   GOOGLE_DCHECK(value != nullptr);
@@ -1500,8 +1538,9 @@
   return options_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Option* Type::add_options() {
+  PROTOBUF_NAMESPACE_ID::Option* _add = _internal_add_options();
   // @@protoc_insertion_point(field_add:google.protobuf.Type.options)
-  return _internal_add_options();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Option >&
 Type::options() const {
@@ -1563,8 +1602,9 @@
   return source_context_;
 }
 inline PROTOBUF_NAMESPACE_ID::SourceContext* Type::mutable_source_context() {
+  PROTOBUF_NAMESPACE_ID::SourceContext* _msg = _internal_mutable_source_context();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Type.source_context)
-  return _internal_mutable_source_context();
+  return _msg;
 }
 inline void Type::set_allocated_source_context(PROTOBUF_NAMESPACE_ID::SourceContext* source_context) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -1688,8 +1728,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Field.name)
 }
 inline std::string* Field::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Field.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Field::_internal_name() const {
   return name_.Get();
@@ -1733,8 +1774,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Field.type_url)
 }
 inline std::string* Field::mutable_type_url() {
+  std::string* _s = _internal_mutable_type_url();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Field.type_url)
-  return _internal_mutable_type_url();
+  return _s;
 }
 inline const std::string& Field::_internal_type_url() const {
   return type_url_.Get();
@@ -1832,8 +1874,9 @@
   return options_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Option* Field::add_options() {
+  PROTOBUF_NAMESPACE_ID::Option* _add = _internal_add_options();
   // @@protoc_insertion_point(field_add:google.protobuf.Field.options)
-  return _internal_add_options();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Option >&
 Field::options() const {
@@ -1857,8 +1900,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Field.json_name)
 }
 inline std::string* Field::mutable_json_name() {
+  std::string* _s = _internal_mutable_json_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Field.json_name)
-  return _internal_mutable_json_name();
+  return _s;
 }
 inline const std::string& Field::_internal_json_name() const {
   return json_name_.Get();
@@ -1902,8 +1946,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Field.default_value)
 }
 inline std::string* Field::mutable_default_value() {
+  std::string* _s = _internal_mutable_default_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Field.default_value)
-  return _internal_mutable_default_value();
+  return _s;
 }
 inline const std::string& Field::_internal_default_value() const {
   return default_value_.Get();
@@ -1951,8 +1996,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Enum.name)
 }
 inline std::string* Enum::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Enum.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Enum::_internal_name() const {
   return name_.Get();
@@ -2010,8 +2056,9 @@
   return enumvalue_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::EnumValue* Enum::add_enumvalue() {
+  PROTOBUF_NAMESPACE_ID::EnumValue* _add = _internal_add_enumvalue();
   // @@protoc_insertion_point(field_add:google.protobuf.Enum.enumvalue)
-  return _internal_add_enumvalue();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::EnumValue >&
 Enum::enumvalue() const {
@@ -2049,8 +2096,9 @@
   return options_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Option* Enum::add_options() {
+  PROTOBUF_NAMESPACE_ID::Option* _add = _internal_add_options();
   // @@protoc_insertion_point(field_add:google.protobuf.Enum.options)
-  return _internal_add_options();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Option >&
 Enum::options() const {
@@ -2112,8 +2160,9 @@
   return source_context_;
 }
 inline PROTOBUF_NAMESPACE_ID::SourceContext* Enum::mutable_source_context() {
+  PROTOBUF_NAMESPACE_ID::SourceContext* _msg = _internal_mutable_source_context();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Enum.source_context)
-  return _internal_mutable_source_context();
+  return _msg;
 }
 inline void Enum::set_allocated_source_context(PROTOBUF_NAMESPACE_ID::SourceContext* source_context) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
@@ -2177,8 +2226,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.EnumValue.name)
 }
 inline std::string* EnumValue::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.EnumValue.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& EnumValue::_internal_name() const {
   return name_.Get();
@@ -2256,8 +2306,9 @@
   return options_.Add();
 }
 inline PROTOBUF_NAMESPACE_ID::Option* EnumValue::add_options() {
+  PROTOBUF_NAMESPACE_ID::Option* _add = _internal_add_options();
   // @@protoc_insertion_point(field_add:google.protobuf.EnumValue.options)
-  return _internal_add_options();
+  return _add;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::RepeatedPtrField< PROTOBUF_NAMESPACE_ID::Option >&
 EnumValue::options() const {
@@ -2285,8 +2336,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.Option.name)
 }
 inline std::string* Option::mutable_name() {
+  std::string* _s = _internal_mutable_name();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Option.name)
-  return _internal_mutable_name();
+  return _s;
 }
 inline const std::string& Option::_internal_name() const {
   return name_.Get();
@@ -2368,8 +2420,9 @@
   return value_;
 }
 inline PROTOBUF_NAMESPACE_ID::Any* Option::mutable_value() {
+  PROTOBUF_NAMESPACE_ID::Any* _msg = _internal_mutable_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.Option.value)
-  return _internal_mutable_value();
+  return _msg;
 }
 inline void Option::set_allocated_value(PROTOBUF_NAMESPACE_ID::Any* value) {
   ::PROTOBUF_NAMESPACE_ID::Arena* message_arena = GetArenaForAllocation();
diff --git a/src/google/protobuf/unittest.proto b/src/google/protobuf/unittest.proto
index 032a880..0925165 100644
--- a/src/google/protobuf/unittest.proto
+++ b/src/google/protobuf/unittest.proto
@@ -752,6 +752,10 @@
     string bar_string_piece = 15 [ctype=STRING_PIECE, default = "SPIECE"];
     bytes bar_bytes = 16 [default = "BYTES"];
     NestedEnum bar_enum = 17 [default = BAR];
+    string bar_string_with_empty_default = 20 [default = ""];
+    string bar_cord_with_empty_default = 21 [ctype=CORD, default = ""];
+    string bar_string_piece_with_empty_default = 22 [ctype=STRING_PIECE, default = ""];
+    bytes bar_bytes_with_empty_default = 23 [default = ""];
   }
 
   optional int32 baz_int = 18;
diff --git a/src/google/protobuf/unknown_field_set.cc b/src/google/protobuf/unknown_field_set.cc
index 8ab4a1a..1e81116 100644
--- a/src/google/protobuf/unknown_field_set.cc
+++ b/src/google/protobuf/unknown_field_set.cc
@@ -37,11 +37,14 @@
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/parse_context.h>
-#include <google/protobuf/wire_format_lite.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
+#include <google/protobuf/extension_set.h>
+#include <google/protobuf/generated_message_tctable_decl.h>
+#include <google/protobuf/generated_message_tctable_impl.h>
 #include <google/protobuf/wire_format.h>
+#include <google/protobuf/wire_format_lite.h>
 #include <google/protobuf/stubs/stl_util.h>
 
 #include <google/protobuf/port_def.inc>
diff --git a/src/google/protobuf/wrappers.pb.cc b/src/google/protobuf/wrappers.pb.cc
index 6f346ee..2732140 100644
--- a/src/google/protobuf/wrappers.pb.cc
+++ b/src/google/protobuf/wrappers.pb.cc
@@ -245,10 +245,13 @@
  public:
 };
 
-DoubleValue::DoubleValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+DoubleValue::DoubleValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DoubleValue)
 }
 DoubleValue::DoubleValue(const DoubleValue& from)
@@ -258,17 +261,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DoubleValue)
 }
 
-void DoubleValue::SharedCtor() {
+inline void DoubleValue::SharedCtor() {
 value_ = 0;
 }
 
 DoubleValue::~DoubleValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.DoubleValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void DoubleValue::SharedDtor() {
+inline void DoubleValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -370,38 +374,29 @@
   return total_size;
 }
 
-void DoubleValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DoubleValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const DoubleValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<DoubleValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DoubleValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DoubleValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData DoubleValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    DoubleValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*DoubleValue::GetClassData() const { return &_class_data_; }
+
+void DoubleValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<DoubleValue *>(to)->MergeFrom(
+      static_cast<const DoubleValue &>(from));
 }
 
+
 void DoubleValue::MergeFrom(const DoubleValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DoubleValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (!(from.value() <= 0 && from.value() >= 0)) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void DoubleValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DoubleValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void DoubleValue::CopyFrom(const DoubleValue& from) {
@@ -433,10 +428,13 @@
  public:
 };
 
-FloatValue::FloatValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+FloatValue::FloatValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FloatValue)
 }
 FloatValue::FloatValue(const FloatValue& from)
@@ -446,17 +444,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FloatValue)
 }
 
-void FloatValue::SharedCtor() {
+inline void FloatValue::SharedCtor() {
 value_ = 0;
 }
 
 FloatValue::~FloatValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.FloatValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void FloatValue::SharedDtor() {
+inline void FloatValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -558,38 +557,29 @@
   return total_size;
 }
 
-void FloatValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FloatValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const FloatValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<FloatValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FloatValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FloatValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData FloatValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    FloatValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*FloatValue::GetClassData() const { return &_class_data_; }
+
+void FloatValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<FloatValue *>(to)->MergeFrom(
+      static_cast<const FloatValue &>(from));
 }
 
+
 void FloatValue::MergeFrom(const FloatValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FloatValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (!(from.value() <= 0 && from.value() >= 0)) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void FloatValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FloatValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void FloatValue::CopyFrom(const FloatValue& from) {
@@ -621,10 +611,13 @@
  public:
 };
 
-Int64Value::Int64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Int64Value::Int64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Int64Value)
 }
 Int64Value::Int64Value(const Int64Value& from)
@@ -634,17 +627,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Int64Value)
 }
 
-void Int64Value::SharedCtor() {
+inline void Int64Value::SharedCtor() {
 value_ = int64_t{0};
 }
 
 Int64Value::~Int64Value() {
   // @@protoc_insertion_point(destructor:google.protobuf.Int64Value)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Int64Value::SharedDtor() {
+inline void Int64Value::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -748,38 +742,29 @@
   return total_size;
 }
 
-void Int64Value::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Int64Value)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Int64Value* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Int64Value>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Int64Value)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Int64Value)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Int64Value::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Int64Value::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Int64Value::GetClassData() const { return &_class_data_; }
+
+void Int64Value::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Int64Value *>(to)->MergeFrom(
+      static_cast<const Int64Value &>(from));
 }
 
+
 void Int64Value::MergeFrom(const Int64Value& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Int64Value)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (from.value() != 0) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void Int64Value::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Int64Value)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Int64Value::CopyFrom(const Int64Value& from) {
@@ -811,10 +796,13 @@
  public:
 };
 
-UInt64Value::UInt64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+UInt64Value::UInt64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.UInt64Value)
 }
 UInt64Value::UInt64Value(const UInt64Value& from)
@@ -824,17 +812,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.UInt64Value)
 }
 
-void UInt64Value::SharedCtor() {
+inline void UInt64Value::SharedCtor() {
 value_ = uint64_t{0u};
 }
 
 UInt64Value::~UInt64Value() {
   // @@protoc_insertion_point(destructor:google.protobuf.UInt64Value)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void UInt64Value::SharedDtor() {
+inline void UInt64Value::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -938,38 +927,29 @@
   return total_size;
 }
 
-void UInt64Value::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UInt64Value)
-  GOOGLE_DCHECK_NE(&from, this);
-  const UInt64Value* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<UInt64Value>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UInt64Value)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UInt64Value)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData UInt64Value::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    UInt64Value::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*UInt64Value::GetClassData() const { return &_class_data_; }
+
+void UInt64Value::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<UInt64Value *>(to)->MergeFrom(
+      static_cast<const UInt64Value &>(from));
 }
 
+
 void UInt64Value::MergeFrom(const UInt64Value& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UInt64Value)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (from.value() != 0) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void UInt64Value::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UInt64Value)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void UInt64Value::CopyFrom(const UInt64Value& from) {
@@ -1001,10 +981,13 @@
  public:
 };
 
-Int32Value::Int32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+Int32Value::Int32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.Int32Value)
 }
 Int32Value::Int32Value(const Int32Value& from)
@@ -1014,17 +997,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Int32Value)
 }
 
-void Int32Value::SharedCtor() {
+inline void Int32Value::SharedCtor() {
 value_ = 0;
 }
 
 Int32Value::~Int32Value() {
   // @@protoc_insertion_point(destructor:google.protobuf.Int32Value)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void Int32Value::SharedDtor() {
+inline void Int32Value::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -1128,38 +1112,29 @@
   return total_size;
 }
 
-void Int32Value::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Int32Value)
-  GOOGLE_DCHECK_NE(&from, this);
-  const Int32Value* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<Int32Value>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Int32Value)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Int32Value)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData Int32Value::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    Int32Value::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*Int32Value::GetClassData() const { return &_class_data_; }
+
+void Int32Value::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<Int32Value *>(to)->MergeFrom(
+      static_cast<const Int32Value &>(from));
 }
 
+
 void Int32Value::MergeFrom(const Int32Value& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Int32Value)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (from.value() != 0) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void Int32Value::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Int32Value)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void Int32Value::CopyFrom(const Int32Value& from) {
@@ -1191,10 +1166,13 @@
  public:
 };
 
-UInt32Value::UInt32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+UInt32Value::UInt32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.UInt32Value)
 }
 UInt32Value::UInt32Value(const UInt32Value& from)
@@ -1204,17 +1182,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.UInt32Value)
 }
 
-void UInt32Value::SharedCtor() {
+inline void UInt32Value::SharedCtor() {
 value_ = 0u;
 }
 
 UInt32Value::~UInt32Value() {
   // @@protoc_insertion_point(destructor:google.protobuf.UInt32Value)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void UInt32Value::SharedDtor() {
+inline void UInt32Value::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -1318,38 +1297,29 @@
   return total_size;
 }
 
-void UInt32Value::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UInt32Value)
-  GOOGLE_DCHECK_NE(&from, this);
-  const UInt32Value* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<UInt32Value>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UInt32Value)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UInt32Value)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData UInt32Value::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    UInt32Value::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*UInt32Value::GetClassData() const { return &_class_data_; }
+
+void UInt32Value::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<UInt32Value *>(to)->MergeFrom(
+      static_cast<const UInt32Value &>(from));
 }
 
+
 void UInt32Value::MergeFrom(const UInt32Value& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UInt32Value)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (from.value() != 0) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void UInt32Value::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UInt32Value)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void UInt32Value::CopyFrom(const UInt32Value& from) {
@@ -1381,10 +1351,13 @@
  public:
 };
 
-BoolValue::BoolValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+BoolValue::BoolValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.BoolValue)
 }
 BoolValue::BoolValue(const BoolValue& from)
@@ -1394,17 +1367,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.BoolValue)
 }
 
-void BoolValue::SharedCtor() {
+inline void BoolValue::SharedCtor() {
 value_ = false;
 }
 
 BoolValue::~BoolValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.BoolValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void BoolValue::SharedDtor() {
+inline void BoolValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
 }
 
@@ -1506,38 +1480,29 @@
   return total_size;
 }
 
-void BoolValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.BoolValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const BoolValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<BoolValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.BoolValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.BoolValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData BoolValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    BoolValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*BoolValue::GetClassData() const { return &_class_data_; }
+
+void BoolValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<BoolValue *>(to)->MergeFrom(
+      static_cast<const BoolValue &>(from));
 }
 
+
 void BoolValue::MergeFrom(const BoolValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.BoolValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (from.value() != 0) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void BoolValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.BoolValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void BoolValue::CopyFrom(const BoolValue& from) {
@@ -1569,10 +1534,13 @@
  public:
 };
 
-StringValue::StringValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+StringValue::StringValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.StringValue)
 }
 StringValue::StringValue(const StringValue& from)
@@ -1586,17 +1554,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.StringValue)
 }
 
-void StringValue::SharedCtor() {
+inline void StringValue::SharedCtor() {
 value_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
 
 StringValue::~StringValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.StringValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void StringValue::SharedDtor() {
+inline void StringValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -1707,38 +1676,29 @@
   return total_size;
 }
 
-void StringValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.StringValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const StringValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<StringValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.StringValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.StringValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData StringValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    StringValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*StringValue::GetClassData() const { return &_class_data_; }
+
+void StringValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<StringValue *>(to)->MergeFrom(
+      static_cast<const StringValue &>(from));
 }
 
+
 void StringValue::MergeFrom(const StringValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.StringValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (!from.value().empty()) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void StringValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.StringValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void StringValue::CopyFrom(const StringValue& from) {
@@ -1774,10 +1734,13 @@
  public:
 };
 
-BytesValue::BytesValue(::PROTOBUF_NAMESPACE_ID::Arena* arena)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+BytesValue::BytesValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                         bool is_message_owned)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
   SharedCtor();
-  RegisterArenaDtor(arena);
+  if (!is_message_owned) {
+    RegisterArenaDtor(arena);
+  }
   // @@protoc_insertion_point(arena_constructor:google.protobuf.BytesValue)
 }
 BytesValue::BytesValue(const BytesValue& from)
@@ -1791,17 +1754,18 @@
   // @@protoc_insertion_point(copy_constructor:google.protobuf.BytesValue)
 }
 
-void BytesValue::SharedCtor() {
+inline void BytesValue::SharedCtor() {
 value_.UnsafeSetDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
 
 BytesValue::~BytesValue() {
   // @@protoc_insertion_point(destructor:google.protobuf.BytesValue)
+  if (GetArenaForAllocation() != nullptr) return;
   SharedDtor();
   _internal_metadata_.Delete<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>();
 }
 
-void BytesValue::SharedDtor() {
+inline void BytesValue::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
   value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
 }
@@ -1907,38 +1871,29 @@
   return total_size;
 }
 
-void BytesValue::MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.BytesValue)
-  GOOGLE_DCHECK_NE(&from, this);
-  const BytesValue* source =
-      ::PROTOBUF_NAMESPACE_ID::DynamicCastToGenerated<BytesValue>(
-          &from);
-  if (source == nullptr) {
-  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.BytesValue)
-    ::PROTOBUF_NAMESPACE_ID::internal::ReflectionOps::Merge(from, this);
-  } else {
-  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.BytesValue)
-    MergeFrom(*source);
-  }
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData BytesValue::_class_data_ = {
+    ::PROTOBUF_NAMESPACE_ID::Message::CopyWithSizeCheck,
+    BytesValue::MergeImpl
+};
+const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*BytesValue::GetClassData() const { return &_class_data_; }
+
+void BytesValue::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to,
+                      const ::PROTOBUF_NAMESPACE_ID::Message&from) {
+  static_cast<BytesValue *>(to)->MergeFrom(
+      static_cast<const BytesValue &>(from));
 }
 
+
 void BytesValue::MergeFrom(const BytesValue& from) {
 // @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.BytesValue)
   GOOGLE_DCHECK_NE(&from, this);
-  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::uint32 cached_has_bits = 0;
   (void) cached_has_bits;
 
   if (!from.value().empty()) {
     _internal_set_value(from._internal_value());
   }
-}
-
-void BytesValue::CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) {
-// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.BytesValue)
-  if (&from == this) return;
-  Clear();
-  MergeFrom(from);
+  _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
 }
 
 void BytesValue::CopyFrom(const BytesValue& from) {
diff --git a/src/google/protobuf/wrappers.pb.h b/src/google/protobuf/wrappers.pb.h
index e890dff..9bf9495 100644
--- a/src/google/protobuf/wrappers.pb.h
+++ b/src/google/protobuf/wrappers.pb.h
@@ -169,10 +169,13 @@
   DoubleValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<DoubleValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const DoubleValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const DoubleValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -192,12 +195,16 @@
     return "google.protobuf.DoubleValue";
   }
   protected:
-  explicit DoubleValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit DoubleValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -301,10 +308,13 @@
   FloatValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<FloatValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const FloatValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const FloatValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -324,12 +334,16 @@
     return "google.protobuf.FloatValue";
   }
   protected:
-  explicit FloatValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit FloatValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -433,10 +447,13 @@
   Int64Value* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Int64Value>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Int64Value& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Int64Value& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -456,12 +473,16 @@
     return "google.protobuf.Int64Value";
   }
   protected:
-  explicit Int64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Int64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -565,10 +586,13 @@
   UInt64Value* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<UInt64Value>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const UInt64Value& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const UInt64Value& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -588,12 +612,16 @@
     return "google.protobuf.UInt64Value";
   }
   protected:
-  explicit UInt64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit UInt64Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -697,10 +725,13 @@
   Int32Value* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<Int32Value>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const Int32Value& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const Int32Value& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -720,12 +751,16 @@
     return "google.protobuf.Int32Value";
   }
   protected:
-  explicit Int32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit Int32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -829,10 +864,13 @@
   UInt32Value* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<UInt32Value>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const UInt32Value& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const UInt32Value& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -852,12 +890,16 @@
     return "google.protobuf.UInt32Value";
   }
   protected:
-  explicit UInt32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit UInt32Value(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -961,10 +1003,13 @@
   BoolValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<BoolValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const BoolValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const BoolValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -984,12 +1029,16 @@
     return "google.protobuf.BoolValue";
   }
   protected:
-  explicit BoolValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit BoolValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1093,10 +1142,13 @@
   StringValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<StringValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const StringValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const StringValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1116,12 +1168,16 @@
     return "google.protobuf.StringValue";
   }
   protected:
-  explicit StringValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit StringValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1137,7 +1193,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_value();
   void set_allocated_value(std::string* value);
   private:
   const std::string& _internal_value() const;
@@ -1230,10 +1286,13 @@
   BytesValue* New(::PROTOBUF_NAMESPACE_ID::Arena* arena) const final {
     return CreateMaybeMessage<BytesValue>(arena);
   }
-  void CopyFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
-  void MergeFrom(const ::PROTOBUF_NAMESPACE_ID::Message& from) final;
+  using ::PROTOBUF_NAMESPACE_ID::Message::CopyFrom;
   void CopyFrom(const BytesValue& from);
+  using ::PROTOBUF_NAMESPACE_ID::Message::MergeFrom;
   void MergeFrom(const BytesValue& from);
+  private:
+  static void MergeImpl(::PROTOBUF_NAMESPACE_ID::Message*to, const ::PROTOBUF_NAMESPACE_ID::Message&from);
+  public:
   PROTOBUF_ATTRIBUTE_REINITIALIZES void Clear() final;
   bool IsInitialized() const final;
 
@@ -1253,12 +1312,16 @@
     return "google.protobuf.BytesValue";
   }
   protected:
-  explicit BytesValue(::PROTOBUF_NAMESPACE_ID::Arena* arena);
+  explicit BytesValue(::PROTOBUF_NAMESPACE_ID::Arena* arena,
+                       bool is_message_owned = false);
   private:
   static void ArenaDtor(void* object);
   inline void RegisterArenaDtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
+  static const ClassData _class_data_;
+  const ::PROTOBUF_NAMESPACE_ID::Message::ClassData*GetClassData() const final;
+
   ::PROTOBUF_NAMESPACE_ID::Metadata GetMetadata() const final;
 
   // nested types ----------------------------------------------------
@@ -1274,7 +1337,7 @@
   template <typename ArgT0 = const std::string&, typename... ArgT>
   void set_value(ArgT0&& arg0, ArgT... args);
   std::string* mutable_value();
-  PROTOBUF_FUTURE_MUST_USE_RESULT std::string* release_value();
+  PROTOBUF_MUST_USE_RESULT std::string* release_value();
   void set_allocated_value(std::string* value);
   private:
   const std::string& _internal_value() const;
@@ -1488,8 +1551,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.StringValue.value)
 }
 inline std::string* StringValue::mutable_value() {
+  std::string* _s = _internal_mutable_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.StringValue.value)
-  return _internal_mutable_value();
+  return _s;
 }
 inline const std::string& StringValue::_internal_value() const {
   return value_.Get();
@@ -1537,8 +1601,9 @@
   // @@protoc_insertion_point(field_set:google.protobuf.BytesValue.value)
 }
 inline std::string* BytesValue::mutable_value() {
+  std::string* _s = _internal_mutable_value();
   // @@protoc_insertion_point(field_mutable:google.protobuf.BytesValue.value)
-  return _internal_mutable_value();
+  return _s;
 }
 inline const std::string& BytesValue::_internal_value() const {
   return value_.Get();