upb: lock down MiniTableField

PiperOrigin-RevId: 586171362
diff --git a/upb/message/accessors.h b/upb/message/accessors.h
index 12b81ce..703d506 100644
--- a/upb/message/accessors.h
+++ b/upb/message/accessors.h
@@ -105,8 +105,9 @@
                                         const upb_MiniTableField* field,
                                         bool default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Bool);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_1Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue def;
   def.bool_val = default_val;
   return upb_Message_GetField(msg, field, def).bool_val;
@@ -116,8 +117,9 @@
                                         const upb_MiniTableField* field,
                                         bool value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Bool);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_1Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.bool_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -128,8 +130,9 @@
                                             int32_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int32 ||
              upb_MiniTableField_CType(field) == kUpb_CType_Enum);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.int32_val = default_val;
@@ -141,8 +144,9 @@
                                          int32_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int32 ||
              upb_MiniTableField_CType(field) == kUpb_CType_Enum);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.int32_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -152,8 +156,9 @@
                                               const upb_MiniTableField* field,
                                               uint32_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt32);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.uint32_val = default_val;
@@ -164,8 +169,9 @@
                                           const upb_MiniTableField* field,
                                           uint32_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt32);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.uint32_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -175,8 +181,9 @@
     upb_Message* msg, const upb_MiniTable* msg_mini_table,
     const upb_MiniTableField* field, int32_t value) {
   UPB_ASSERT(upb_MiniTableField_IsClosedEnum(field));
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   UPB_ASSERT(upb_MiniTableEnum_CheckValue(
       upb_MiniTable_GetSubEnumTable(msg_mini_table, field), value));
   _upb_Message_SetNonExtensionField(msg, field, &value);
@@ -186,8 +193,9 @@
                                             const upb_MiniTableField* field,
                                             int64_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int64);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_8Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.int64_val = default_val;
@@ -198,8 +206,9 @@
                                          const upb_MiniTableField* field,
                                          int64_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int64);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_8Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.int64_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -209,8 +218,9 @@
                                               const upb_MiniTableField* field,
                                               uint64_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt64);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_8Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.uint64_val = default_val;
@@ -221,8 +231,9 @@
                                           const upb_MiniTableField* field,
                                           uint64_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt64);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_8Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.uint64_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -232,8 +243,9 @@
                                           const upb_MiniTableField* field,
                                           float default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Float);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.float_val = default_val;
@@ -244,8 +256,9 @@
                                          const upb_MiniTableField* field,
                                          float value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Float);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_4Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.float_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -255,8 +268,9 @@
                                             const upb_MiniTableField* field,
                                             double default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Double);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_8Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.double_val = default_val;
@@ -267,8 +281,9 @@
                                           const upb_MiniTableField* field,
                                           double value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Double);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_8Byte);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.double_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -279,8 +294,9 @@
                       upb_StringView default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_String ||
              upb_MiniTableField_CType(field) == kUpb_CType_Bytes);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_StringView);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_StringView);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
 
   upb_MessageValue def;
   def.str_val = default_val;
@@ -292,8 +308,9 @@
                                           upb_StringView value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_String ||
              upb_MiniTableField_CType(field) == kUpb_CType_Bytes);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_StringView);
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+             kUpb_FieldRep_StringView);
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_MessageValue val;
   val.str_val = value;
   return upb_Message_SetField(msg, field, val, a);
@@ -303,9 +320,9 @@
     const upb_Message* msg, const upb_MiniTableField* field,
     upb_Message* default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Message);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) ==
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
              UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte));
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   upb_TaggedMessagePtr tagged;
   _upb_Message_GetNonExtensionField(msg, field, &default_val, &tagged);
   return tagged;
@@ -326,9 +343,9 @@
     upb_Message* msg, const upb_MiniTable* mini_table,
     const upb_MiniTableField* field, upb_TaggedMessagePtr sub_message) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Message);
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) ==
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
              UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte));
-  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
+  UPB_ASSUME(upb_MiniTableField_IsScalar(field));
   UPB_ASSERT(mini_table->subs[field->UPB_PRIVATE(submsg_index)].submsg);
   _upb_Message_SetNonExtensionField(msg, field, &sub_message);
 }
@@ -360,7 +377,7 @@
 
 UPB_API_INLINE const upb_Array* upb_Message_GetArray(
     const upb_Message* msg, const upb_MiniTableField* field) {
-  _upb_MiniTableField_CheckIsArray(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(field);
   upb_Array* ret;
   const upb_Array* default_val = NULL;
   _upb_Message_GetNonExtensionField(msg, field, &default_val, &ret);
@@ -369,20 +386,20 @@
 
 UPB_API_INLINE upb_Array* upb_Message_GetMutableArray(
     upb_Message* msg, const upb_MiniTableField* field) {
-  _upb_MiniTableField_CheckIsArray(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(field);
   return (upb_Array*)upb_Message_GetArray(msg, field);
 }
 
 UPB_API_INLINE upb_Array* upb_Message_GetOrCreateMutableArray(
     upb_Message* msg, const upb_MiniTableField* field, upb_Arena* arena) {
   UPB_ASSERT(arena);
-  _upb_MiniTableField_CheckIsArray(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(field);
   upb_Array* array = upb_Message_GetMutableArray(msg, field);
   if (!array) {
-    array = UPB_PRIVATE(_upb_Array_New)(arena, 4,
-                                        _upb_MiniTableField_ElemSizeLg2(field));
+    array = UPB_PRIVATE(_upb_Array_New)(
+        arena, 4, UPB_PRIVATE(_upb_MiniTableField_ElemSizeLg2)(field));
     // Check again due to: https://godbolt.org/z/7WfaoKG1r
-    _upb_MiniTableField_CheckIsArray(field);
+    UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(field);
     upb_MessageValue val;
     val.array_val = array;
     upb_Message_SetField(msg, field, val, arena);
@@ -393,7 +410,7 @@
 UPB_API_INLINE void* upb_Message_ResizeArrayUninitialized(
     upb_Message* msg, const upb_MiniTableField* field, size_t size,
     upb_Arena* arena) {
-  _upb_MiniTableField_CheckIsArray(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(field);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, field, arena);
   if (!arr || !_upb_Array_ResizeUninitialized(arr, size, arena)) return NULL;
   return _upb_array_ptr(arr);
@@ -401,7 +418,7 @@
 
 UPB_API_INLINE const upb_Map* upb_Message_GetMap(
     const upb_Message* msg, const upb_MiniTableField* field) {
-  _upb_MiniTableField_CheckIsMap(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsMap)(field);
   _upb_Message_AssertMapIsUntagged(msg, field);
   upb_Map* ret;
   const upb_Map* default_val = NULL;
diff --git a/upb/message/copy.c b/upb/message/copy.c
index e0977c4..4be6573 100644
--- a/upb/message/copy.c
+++ b/upb/message/copy.c
@@ -33,10 +33,6 @@
 // Must be last.
 #include "upb/port/def.inc"
 
-static bool upb_MessageField_IsMap(const upb_MiniTableField* field) {
-  return upb_FieldMode_Get(field) == kUpb_FieldMode_Map;
-}
-
 static upb_StringView upb_Clone_StringView(upb_StringView str,
                                            upb_Arena* arena) {
   if (str.size == 0) {
@@ -164,7 +160,7 @@
                                         const upb_MiniTable* mini_table,
                                         const upb_MiniTableField* field,
                                         upb_Message* clone, upb_Arena* arena) {
-  _upb_MiniTableField_CheckIsArray(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(field);
   upb_Array* cloned_array = upb_Array_DeepClone(
       array, upb_MiniTableField_CType(field),
       upb_MiniTableField_CType(field) == kUpb_CType_Message &&
@@ -197,7 +193,7 @@
   memcpy(dst, src, mini_table->size);
   for (size_t i = 0; i < mini_table->field_count; ++i) {
     const upb_MiniTableField* field = &mini_table->fields[i];
-    if (!upb_MiniTableField_IsRepeatedOrMap(field)) {
+    if (upb_MiniTableField_IsScalar(field)) {
       switch (upb_MiniTableField_CType(field)) {
         case kUpb_CType_Message: {
           upb_TaggedMessagePtr tagged =
@@ -237,7 +233,7 @@
           break;
       }
     } else {
-      if (upb_MessageField_IsMap(field)) {
+      if (upb_MiniTableField_IsMap(field)) {
         const upb_Map* map = upb_Message_GetMap(src, field);
         if (map != NULL) {
           if (!upb_Message_Map_DeepClone(map, mini_table, field, dst, arena)) {
@@ -264,7 +260,7 @@
     upb_Message_Extension* dst_ext =
         _upb_Message_GetOrCreateExtension(dst, msg_ext->ext, arena);
     if (!dst_ext) return NULL;
-    if (!upb_MiniTableField_IsRepeatedOrMap(field)) {
+    if (upb_MiniTableField_IsScalar(field)) {
       if (!upb_Clone_ExtensionValue(msg_ext->ext, msg_ext, dst_ext, arena)) {
         return NULL;
       }
diff --git a/upb/message/internal/accessors.h b/upb/message/internal/accessors.h
index 65f301d..802d2cd 100644
--- a/upb/message/internal/accessors.h
+++ b/upb/message/internal/accessors.h
@@ -148,7 +148,7 @@
 UPB_INLINE bool _upb_MiniTable_ValueIsNonZero(const void* default_val,
                                               const upb_MiniTableField* field) {
   char zero[16] = {0};
-  switch (_upb_MiniTableField_GetRep(field)) {
+  switch (UPB_PRIVATE(_upb_MiniTableField_GetRep)(field)) {
     case kUpb_FieldRep_1Byte:
       return memcmp(&zero, default_val, 1) != 0;
     case kUpb_FieldRep_4Byte:
@@ -165,7 +165,7 @@
 
 UPB_INLINE void _upb_MiniTable_CopyFieldData(void* to, const void* from,
                                              const upb_MiniTableField* field) {
-  switch (_upb_MiniTableField_GetRep(field)) {
+  switch (UPB_PRIVATE(_upb_MiniTableField_GetRep)(field)) {
     case kUpb_FieldRep_1Byte:
       memcpy(to, from, 1);
       return;
@@ -201,8 +201,9 @@
 //                                       const upb_MiniTableField* field,
 //                                       bool value, upb_Arena* a) {
 //     UPB_ASSUME(field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Bool);
-//     UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
-//     UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
+//     UPB_ASSUME(upb_MiniTableField_IsScalar(field));
+//     UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(field) ==
+//                kUpb_FieldRep_1Byte);
 //     upb_Message_SetField(msg, field, &value, a);
 //   }
 //
@@ -269,7 +270,7 @@
 // is unset (as message fields do have presence).
 UPB_INLINE upb_MutableMessageValue _upb_Message_GetMutableField(
     const upb_Message* msg, const upb_MiniTableField* field) {
-  UPB_ASSUME(upb_MiniTableField_IsRepeatedOrMap(field) ||
+  UPB_ASSUME(!upb_MiniTableField_IsScalar(field) ||
              upb_MiniTableField_IsSubMessage(field));
 
   upb_MutableMessageValue default_val;
@@ -335,7 +336,7 @@
 UPB_INLINE void _upb_Message_AssertMapIsUntagged(
     const upb_Message* msg, const upb_MiniTableField* field) {
   UPB_UNUSED(msg);
-  _upb_MiniTableField_CheckIsMap(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsMap)(field);
 #ifndef NDEBUG
   upb_TaggedMessagePtr default_val = 0;
   upb_TaggedMessagePtr tagged;
@@ -347,7 +348,7 @@
 UPB_INLINE upb_Map* _upb_Message_GetOrCreateMutableMap(
     upb_Message* msg, const upb_MiniTableField* field, size_t key_size,
     size_t val_size, upb_Arena* arena) {
-  _upb_MiniTableField_CheckIsMap(field);
+  UPB_PRIVATE(_upb_MiniTableField_CheckIsMap)(field);
   _upb_Message_AssertMapIsUntagged(msg, field);
   upb_Map* map = NULL;
   upb_Map* default_map_value = NULL;
@@ -355,7 +356,7 @@
   if (!map) {
     map = _upb_Map_New(arena, key_size, val_size);
     // Check again due to: https://godbolt.org/z/7WfaoKG1r
-    _upb_MiniTableField_CheckIsMap(field);
+    UPB_PRIVATE(_upb_MiniTableField_CheckIsMap)(field);
     _upb_Message_SetNonExtensionField(msg, field, &map);
   }
   return map;
diff --git a/upb/message/promote.c b/upb/message/promote.c
index f9efd5f..acd3192 100644
--- a/upb/message/promote.c
+++ b/upb/message/promote.c
@@ -329,7 +329,7 @@
   UPB_ASSERT(map_entry_mini_table);
   UPB_ASSERT(map_entry_mini_table);
   UPB_ASSERT(map_entry_mini_table->field_count == 2);
-  UPB_ASSERT(upb_FieldMode_Get(field) == kUpb_FieldMode_Map);
+  UPB_ASSERT(upb_MiniTableField_IsMap(field));
   // Find all unknowns with given field number and parse.
   upb_FindUnknownRet unknown;
   while (1) {
diff --git a/upb/mini_descriptor/decode.c b/upb/mini_descriptor/decode.c
index 7d97708..15db665 100644
--- a/upb/mini_descriptor/decode.c
+++ b/upb/mini_descriptor/decode.c
@@ -638,7 +638,7 @@
                            name, expected_num, (int)f->number);
   }
 
-  if (upb_MiniTableField_IsRepeatedOrMap(f)) {
+  if (!upb_MiniTableField_IsScalar(f)) {
     upb_MdDecoder_ErrorJmp(
         &d->base, "map %s cannot be repeated or map, or be in oneof", name);
   }
@@ -816,7 +816,7 @@
     if (!upb_MiniTableField_IsSubMessage(f)) return NULL;
 
     // Extensions of MessageSet must be non-repeating.
-    if ((f->mode & kUpb_FieldMode_Mask) == kUpb_FieldMode_Array) return NULL;
+    if (upb_MiniTableField_IsArray(f)) return NULL;
   }
 
   ext->UPB_PRIVATE(extendee) = extendee;
diff --git a/upb/mini_descriptor/internal/encode_test.cc b/upb/mini_descriptor/internal/encode_test.cc
index c13a91e..5da2443 100644
--- a/upb/mini_descriptor/internal/encode_test.cc
+++ b/upb/mini_descriptor/internal/encode_test.cc
@@ -65,7 +65,7 @@
   for (int i = 0; i < 16; i++) {
     const upb_MiniTableField* f = &table->fields[i];
     EXPECT_EQ(i + 1, f->number);
-    EXPECT_EQ(kUpb_FieldMode_Scalar, f->mode & kUpb_FieldMode_Mask);
+    EXPECT_TRUE(upb_MiniTableField_IsScalar(f));
     EXPECT_TRUE(offsets.insert(f->offset).second);
     EXPECT_TRUE(f->offset < table->size);
   }
@@ -91,7 +91,7 @@
   for (int i = 0; i < 16; i++) {
     const upb_MiniTableField* f = &table->fields[i];
     EXPECT_EQ(i + 1, f->number);
-    EXPECT_EQ(kUpb_FieldMode_Array, f->mode & kUpb_FieldMode_Mask);
+    EXPECT_TRUE(upb_MiniTableField_IsArray(f));
     EXPECT_TRUE(offsets.insert(f->offset).second);
     EXPECT_TRUE(f->offset < table->size);
   }
@@ -120,7 +120,7 @@
     const upb_MiniTableField* f = &table->fields[i];
     EXPECT_EQ(field_numbers[i], f->number);
     EXPECT_EQ(kUpb_FieldType_Float, upb_MiniTableField_Type(f));
-    EXPECT_EQ(kUpb_FieldMode_Scalar, f->mode & kUpb_FieldMode_Mask);
+    EXPECT_TRUE(upb_MiniTableField_IsScalar(f));
     EXPECT_TRUE(offsets.insert(f->offset).second);
     EXPECT_TRUE(f->offset < table->size);
   }
@@ -149,7 +149,7 @@
   for (int i = 0; i < 16; i++) {
     const upb_MiniTableField* f = &table->fields[i];
     EXPECT_EQ(i + 1, f->number);
-    EXPECT_EQ(kUpb_FieldMode_Scalar, f->mode & kUpb_FieldMode_Mask);
+    EXPECT_TRUE(upb_MiniTableField_IsScalar(f));
     // For a oneof all fields have the same offset.
     EXPECT_EQ(table->fields[0].offset, f->offset);
     // All presence fields should point to the same oneof case offset.
diff --git a/upb/mini_table/field.h b/upb/mini_table/field.h
index b459005..564da00 100644
--- a/upb/mini_table/field.h
+++ b/upb/mini_table/field.h
@@ -8,8 +8,6 @@
 #ifndef UPB_MINI_TABLE_FIELD_H_
 #define UPB_MINI_TABLE_FIELD_H_
 
-#include <stddef.h>
-
 #include "upb/base/descriptor_constants.h"
 #include "upb/mini_table/internal/field.h"
 
@@ -22,57 +20,53 @@
 extern "C" {
 #endif
 
-UPB_API_INLINE upb_FieldType
-upb_MiniTableField_Type(const upb_MiniTableField* f) {
-  if (f->mode & kUpb_LabelFlags_IsAlternate) {
-    if (f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Int32) {
-      return kUpb_FieldType_Enum;
-    } else if (f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Bytes) {
-      return kUpb_FieldType_String;
-    } else {
-      UPB_ASSERT(false);
-    }
-  }
-  return (upb_FieldType)f->UPB_PRIVATE(descriptortype);
-}
-
 UPB_API_INLINE upb_CType upb_MiniTableField_CType(const upb_MiniTableField* f) {
-  return upb_FieldType_CType(upb_MiniTableField_Type(f));
-}
-
-UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
-    const upb_MiniTableField* field) {
-  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
-}
-
-UPB_API_INLINE bool upb_MiniTableField_IsExtension(
-    const upb_MiniTableField* f) {
-  return f->mode & kUpb_LabelFlags_IsExtension;
-}
-
-UPB_API_INLINE bool upb_MiniTableField_IsInOneof(const upb_MiniTableField* f) {
-  return f->presence < 0;
-}
-
-UPB_API_INLINE bool upb_MiniTableField_IsRepeatedOrMap(
-    const upb_MiniTableField* f) {
-  // This works because upb_FieldMode has no value 3.
-  return !(f->mode & kUpb_FieldMode_Scalar);
-}
-
-UPB_API_INLINE bool upb_MiniTableField_IsSubMessage(
-    const upb_MiniTableField* f) {
-  return f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Message ||
-         f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Group;
+  return UPB_PRIVATE(_upb_MiniTableField_CType)(f);
 }
 
 UPB_API_INLINE bool upb_MiniTableField_HasPresence(
     const upb_MiniTableField* f) {
-  if (upb_MiniTableField_IsExtension(f)) {
-    return !upb_MiniTableField_IsRepeatedOrMap(f);
-  } else {
-    return f->presence != 0;
-  }
+  return UPB_PRIVATE(_upb_MiniTableField_HasPresence)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsArray(const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsArray)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
+    const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsClosedEnum)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsExtension(
+    const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsExtension)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsInOneof(const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsInOneof)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsMap(const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsMap)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsPacked(const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsPacked)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsScalar(const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsScalar)(f);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsSubMessage(
+    const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_IsSubMessage)(f);
+}
+
+UPB_API_INLINE upb_FieldType
+upb_MiniTableField_Type(const upb_MiniTableField* f) {
+  return UPB_PRIVATE(_upb_MiniTableField_Type)(f);
 }
 
 #ifdef __cplusplus
diff --git a/upb/mini_table/internal/field.h b/upb/mini_table/internal/field.h
index 4dda1a6..e5274cd 100644
--- a/upb/mini_table/internal/field.h
+++ b/upb/mini_table/internal/field.h
@@ -20,7 +20,7 @@
 struct upb_MiniTableField {
   uint32_t number;
   uint16_t offset;
-  int16_t presence;       // If >0, hasbit_index.  If <0, ~oneof_index
+  int16_t presence;  // If >0, hasbit_index.  If <0, ~oneof_index
 
   // Indexes into `upb_MiniTable.subs`
   // Will be set to `kUpb_NoSub` if `descriptortype` != MESSAGE/GROUP/ENUM
@@ -69,38 +69,110 @@
 
 #define kUpb_FieldRep_Shift 6
 
-UPB_INLINE upb_FieldRep
-_upb_MiniTableField_GetRep(const struct upb_MiniTableField* field) {
-  return (upb_FieldRep)(field->mode >> kUpb_FieldRep_Shift);
-}
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 UPB_INLINE upb_FieldMode
-upb_FieldMode_Get(const struct upb_MiniTableField* field) {
-  return (upb_FieldMode)(field->mode & 3);
+UPB_PRIVATE(_upb_MiniTableField_Mode)(const struct upb_MiniTableField* f) {
+  return (upb_FieldMode)(f->mode & kUpb_FieldMode_Mask);
 }
 
-UPB_INLINE void _upb_MiniTableField_CheckIsArray(
-    const struct upb_MiniTableField* field) {
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_NativePointer);
-  UPB_ASSUME(upb_FieldMode_Get(field) == kUpb_FieldMode_Array);
-  UPB_ASSUME(field->presence == 0);
+UPB_INLINE upb_FieldRep
+UPB_PRIVATE(_upb_MiniTableField_GetRep)(const struct upb_MiniTableField* f) {
+  return (upb_FieldRep)(f->mode >> kUpb_FieldRep_Shift);
 }
 
-UPB_INLINE void _upb_MiniTableField_CheckIsMap(
-    const struct upb_MiniTableField* field) {
-  UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_NativePointer);
-  UPB_ASSUME(upb_FieldMode_Get(field) == kUpb_FieldMode_Map);
-  UPB_ASSUME(field->presence == 0);
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsArray)(
+    const struct upb_MiniTableField* f) {
+  return (f->mode & kUpb_FieldMode_Mask) == kUpb_FieldMode_Array;
 }
 
-UPB_INLINE size_t
-_upb_MiniTableField_ElemSizeLg2(const struct upb_MiniTableField* field) {
-  return upb_FieldType_SizeLg2(
-      (upb_FieldType)field->UPB_PRIVATE(descriptortype));
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsMap)(
+    const struct upb_MiniTableField* f) {
+  return (f->mode & kUpb_FieldMode_Mask) == kUpb_FieldMode_Map;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsScalar)(
+    const struct upb_MiniTableField* f) {
+  return (f->mode & kUpb_FieldMode_Mask) == kUpb_FieldMode_Scalar;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsAlternate)(
+    const struct upb_MiniTableField* f) {
+  return (f->mode & kUpb_LabelFlags_IsAlternate) != 0;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsExtension)(
+    const struct upb_MiniTableField* f) {
+  return (f->mode & kUpb_LabelFlags_IsExtension) != 0;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsPacked)(
+    const struct upb_MiniTableField* f) {
+  return (f->mode & kUpb_LabelFlags_IsPacked) != 0;
+}
+
+UPB_INLINE upb_FieldType
+UPB_PRIVATE(_upb_MiniTableField_Type)(const struct upb_MiniTableField* f) {
+  const upb_FieldType type = (upb_FieldType)f->UPB_PRIVATE(descriptortype);
+  if (UPB_PRIVATE(_upb_MiniTableField_IsAlternate)(f)) {
+    if (type == kUpb_FieldType_Int32) return kUpb_FieldType_Enum;
+    if (type == kUpb_FieldType_Bytes) return kUpb_FieldType_String;
+    UPB_ASSERT(false);
+  }
+  return type;
+}
+
+UPB_INLINE upb_CType
+UPB_PRIVATE(_upb_MiniTableField_CType)(const struct upb_MiniTableField* f) {
+  return upb_FieldType_CType(UPB_PRIVATE(_upb_MiniTableField_Type)(f));
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsClosedEnum)(
+    const struct upb_MiniTableField* f) {
+  return f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsInOneof)(
+    const struct upb_MiniTableField* f) {
+  return f->presence < 0;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_IsSubMessage)(
+    const struct upb_MiniTableField* f) {
+  return f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Message ||
+         f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Group;
+}
+
+UPB_INLINE bool UPB_PRIVATE(_upb_MiniTableField_HasPresence)(
+    const struct upb_MiniTableField* f) {
+  if (UPB_PRIVATE(_upb_MiniTableField_IsExtension)(f)) {
+    return UPB_PRIVATE(_upb_MiniTableField_IsScalar)(f);
+  } else {
+    return f->presence != 0;
+  }
+}
+
+UPB_INLINE void UPB_PRIVATE(_upb_MiniTableField_CheckIsArray)(
+    const struct upb_MiniTableField* f) {
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(f) ==
+             kUpb_FieldRep_NativePointer);
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_IsArray)(f));
+  UPB_ASSUME(f->presence == 0);
+}
+
+UPB_INLINE void UPB_PRIVATE(_upb_MiniTableField_CheckIsMap)(
+    const struct upb_MiniTableField* f) {
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(f) ==
+             kUpb_FieldRep_NativePointer);
+  UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_IsMap)(f));
+  UPB_ASSUME(f->presence == 0);
+}
+
+UPB_INLINE size_t UPB_PRIVATE(_upb_MiniTableField_ElemSizeLg2)(
+    const struct upb_MiniTableField* f) {
+  return upb_FieldType_SizeLg2((upb_FieldType)f->UPB_PRIVATE(descriptortype));
 }
 
 #ifdef __cplusplus
diff --git a/upb/mini_table/message.c b/upb/mini_table/message.c
index 28635cd..db52a54 100644
--- a/upb/mini_table/message.c
+++ b/upb/mini_table/message.c
@@ -8,8 +8,10 @@
 #include "upb/mini_table/message.h"
 
 #include <inttypes.h>
+#include <stddef.h>
+#include <stdint.h>
 
-#include "upb/mem/arena.h"
+#include "upb/mini_table/field.h"
 #include "upb/mini_table/internal/message.h"
 
 // Must be last.
@@ -44,13 +46,9 @@
   return NULL;
 }
 
-static bool upb_MiniTable_Is_Oneof(const upb_MiniTableField* f) {
-  return f->presence < 0;
-}
-
 const upb_MiniTableField* upb_MiniTable_GetOneof(const upb_MiniTable* m,
                                                  const upb_MiniTableField* f) {
-  if (UPB_UNLIKELY(!upb_MiniTable_Is_Oneof(f))) {
+  if (UPB_UNLIKELY(!upb_MiniTableField_IsInOneof(f))) {
     return NULL;
   }
   const upb_MiniTableField* ptr = &m->fields[0];
diff --git a/upb/reflection/BUILD b/upb/reflection/BUILD
index 4880c23..d29a964 100644
--- a/upb/reflection/BUILD
+++ b/upb/reflection/BUILD
@@ -135,7 +135,9 @@
         "//upb:mem",
         "//upb:message",
         "//upb:message_accessors",
+        "//upb:message_accessors_internal",
         "//upb:message_copy",
+        "//upb:message_internal",
         "//upb:message_value",
         "//upb:mini_descriptor",
         "//upb:mini_descriptor_internal",
diff --git a/upb/reflection/message.c b/upb/reflection/message.c
index 2d41a95..3562929 100644
--- a/upb/reflection/message.c
+++ b/upb/reflection/message.c
@@ -7,17 +7,21 @@
 
 #include "upb/reflection/message.h"
 
+#include <stdint.h>
 #include <string.h>
 
-#include "upb/hash/common.h"
+#include "upb/mem/arena.h"
 #include "upb/message/accessors.h"
+#include "upb/message/array.h"
+#include "upb/message/internal/accessors.h"
+#include "upb/message/internal/extension.h"
+#include "upb/message/internal/message.h"
 #include "upb/message/map.h"
 #include "upb/message/message.h"
 #include "upb/mini_table/field.h"
+#include "upb/mini_table/internal/field.h"
 #include "upb/reflection/def.h"
 #include "upb/reflection/def_pool.h"
-#include "upb/reflection/def_type.h"
-#include "upb/reflection/internal/field_def.h"
 #include "upb/reflection/message_def.h"
 #include "upb/reflection/oneof_def.h"
 
@@ -119,7 +123,7 @@
     if (upb_MiniTableField_HasPresence(field)) {
       if (!upb_Message_HasFieldByDef(msg, f)) continue;
     } else {
-      switch (upb_FieldMode_Get(field)) {
+      switch (UPB_PRIVATE(_upb_MiniTableField_Mode)(field)) {
         case kUpb_FieldMode_Map:
           if (!val.map_val || upb_Map_Size(val.map_val) == 0) continue;
           break;
diff --git a/upb/wire/decode.c b/upb/wire/decode.c
index 4706891..113bf55 100644
--- a/upb/wire/decode.c
+++ b/upb/wire/decode.c
@@ -597,8 +597,8 @@
 
   UPB_ASSERT(entry);
   UPB_ASSERT(entry->field_count == 2);
-  UPB_ASSERT(!upb_MiniTableField_IsRepeatedOrMap(&entry->fields[0]));
-  UPB_ASSERT(!upb_MiniTableField_IsRepeatedOrMap(&entry->fields[1]));
+  UPB_ASSERT(upb_MiniTableField_IsScalar(&entry->fields[0]));
+  UPB_ASSERT(upb_MiniTableField_IsScalar(&entry->fields[1]));
 
   if (!map) {
     map = _upb_Decoder_CreateMap(d, entry);
@@ -1043,7 +1043,7 @@
   };
 
   int ndx = field->UPB_PRIVATE(descriptortype);
-  if (upb_FieldMode_Get(field) == kUpb_FieldMode_Array) ndx += kRepeatedBase;
+  if (upb_MiniTableField_IsArray(field)) ndx += kRepeatedBase;
   int op = kDelimitedOps[ndx];
 
   if (op == kUpb_DecodeOp_SubMessage) {
diff --git a/upb/wire/encode.c b/upb/wire/encode.c
index 40aeea2..ca2b465 100644
--- a/upb/wire/encode.c
+++ b/upb/wire/encode.c
@@ -26,6 +26,7 @@
 #include "upb/message/internal/map.h"
 #include "upb/message/internal/map_entry.h"
 #include "upb/message/internal/map_sorter.h"
+#include "upb/message/map.h"
 #include "upb/message/message.h"
 #include "upb/message/tagged_ptr.h"
 #include "upb/mini_table/extension.h"
@@ -307,7 +308,7 @@
                          const upb_MiniTableSub* subs,
                          const upb_MiniTableField* f) {
   const upb_Array* arr = *UPB_PTR_AT(msg, f->offset, upb_Array*);
-  bool packed = f->mode & kUpb_LabelFlags_IsPacked;
+  bool packed = upb_MiniTableField_IsPacked(f);
   size_t pre_len = e->limit - e->ptr;
 
   if (arr == NULL || arr->size == 0) {
@@ -461,7 +462,7 @@
   if (f->presence == 0) {
     // Proto3 presence or map/array.
     const void* mem = UPB_PTR_AT(msg, f->offset, void);
-    switch (_upb_MiniTableField_GetRep(f)) {
+    switch (UPB_PRIVATE(_upb_MiniTableField_GetRep)(f)) {
       case kUpb_FieldRep_1Byte: {
         char ch;
         memcpy(&ch, mem, 1);
@@ -496,7 +497,7 @@
 static void encode_field(upb_encstate* e, const upb_Message* msg,
                          const upb_MiniTableSub* subs,
                          const upb_MiniTableField* field) {
-  switch (upb_FieldMode_Get(field)) {
+  switch (UPB_PRIVATE(_upb_MiniTableField_Mode)(field)) {
     case kUpb_FieldMode_Array:
       encode_array(e, msg, subs, field);
       break;
diff --git a/upb_generator/BUILD b/upb_generator/BUILD
index 917088b..860ca10 100644
--- a/upb_generator/BUILD
+++ b/upb_generator/BUILD
@@ -306,6 +306,7 @@
     deps = [
         "//upb:base",
         "//upb:mem",
+        "//upb:mini_table",
         "//upb:mini_table_internal",
         "//upb:port",
         "//upb:wire_types",
diff --git a/upb_generator/common.cc b/upb_generator/common.cc
index 0e7b5ec..3de4a70 100644
--- a/upb_generator/common.cc
+++ b/upb_generator/common.cc
@@ -140,15 +140,18 @@
 
 std::string GetFieldRep(const upb_MiniTableField* field32,
                         const upb_MiniTableField* field64) {
-  switch (_upb_MiniTableField_GetRep(field32)) {
+  const auto rep32 = UPB_PRIVATE(_upb_MiniTableField_GetRep)(field32);
+  const auto rep64 = UPB_PRIVATE(_upb_MiniTableField_GetRep)(field64);
+
+  switch (rep32) {
     case kUpb_FieldRep_1Byte:
       return "kUpb_FieldRep_1Byte";
       break;
     case kUpb_FieldRep_4Byte: {
-      if (_upb_MiniTableField_GetRep(field64) == kUpb_FieldRep_4Byte) {
+      if (rep64 == kUpb_FieldRep_4Byte) {
         return "kUpb_FieldRep_4Byte";
       } else {
-        assert(_upb_MiniTableField_GetRep(field64) == kUpb_FieldRep_8Byte);
+        assert(rep64 == kUpb_FieldRep_8Byte);
         return "UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte)";
       }
       break;
diff --git a/upb_generator/protoc-gen-upb.cc b/upb_generator/protoc-gen-upb.cc
index f764cd1..6397e16 100644
--- a/upb_generator/protoc-gen-upb.cc
+++ b/upb_generator/protoc-gen-upb.cc
@@ -282,8 +282,9 @@
         R"cc(
           UPB_INLINE $0 $1_$2(const struct $3* msg) {
             const upb_MiniTableExtension* ext = &$4;
-            UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(&ext->UPB_PRIVATE(field)));
-            UPB_ASSUME(_upb_MiniTableField_GetRep(&ext->UPB_PRIVATE(field)) == $5);
+            UPB_ASSUME(upb_MiniTableField_IsScalar(&ext->UPB_PRIVATE(field)));
+            UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(
+                           &ext->UPB_PRIVATE(field)) == $5);
             $0 default_val = $6;
             $0 ret;
             _upb_Message_GetExtensionField(msg, ext, &default_val, &ret);
@@ -297,8 +298,9 @@
         R"cc(
           UPB_INLINE void $1_set_$2(struct $3* msg, $0 val, upb_Arena* arena) {
             const upb_MiniTableExtension* ext = &$4;
-            UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(&ext->UPB_PRIVATE(field)));
-            UPB_ASSUME(_upb_MiniTableField_GetRep(&ext->UPB_PRIVATE(field)) == $5);
+            UPB_ASSUME(upb_MiniTableField_IsScalar(&ext->UPB_PRIVATE(field)));
+            UPB_ASSUME(UPB_PRIVATE(_upb_MiniTableField_GetRep)(
+                           &ext->UPB_PRIVATE(field)) == $5);
             bool ok = _upb_Message_SetExtensionField(msg, ext, &val, arena);
             UPB_ASSERT(ok);
           }
diff --git a/upb_generator/protoc-gen-upb_minitable.cc b/upb_generator/protoc-gen-upb_minitable.cc
index dc3441a..79b59eb 100644
--- a/upb_generator/protoc-gen-upb_minitable.cc
+++ b/upb_generator/protoc-gen-upb_minitable.cc
@@ -5,6 +5,8 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
+#include <string.h>
+
 #include <algorithm>
 #include <cstddef>
 #include <cstdint>
@@ -17,18 +19,20 @@
 
 #include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
-#include "absl/strings/escaping.h"
 #include "absl/strings/str_cat.h"
-#include "absl/strings/str_replace.h"
 #include "absl/strings/string_view.h"
 #include "absl/strings/substitute.h"
 #include "upb/base/descriptor_constants.h"
+#include "upb/base/status.hpp"
 #include "upb/base/string_view.h"
+#include "upb/mini_table/enum.h"
+#include "upb/mini_table/field.h"
+#include "upb/mini_table/internal/field.h"
+#include "upb/mini_table/message.h"
 #include "upb/reflection/def.hpp"
 #include "upb/wire/types.h"
 #include "upb_generator/common.h"
 #include "upb_generator/file_layout.h"
-#include "upb_generator/names.h"
 #include "upb_generator/plugin.h"
 
 // Must be last.
@@ -62,7 +66,7 @@
 }
 
 std::string ExtensionIdentBase(upb::FieldDefPtr ext) {
-  assert(ext.is_extension());
+  UPB_ASSERT(ext.is_extension());
   std::string ext_scope;
   if (ext.extension_scope()) {
     return MessageName(ext.extension_scope());
@@ -263,23 +267,12 @@
       return false;  // Not supported yet.
   }
 
-  switch (upb_FieldMode_Get(mt_f)) {
-    case kUpb_FieldMode_Map:
-      return false;  // Not supported yet (ever?).
-    case kUpb_FieldMode_Array:
-      if (mt_f->mode & kUpb_LabelFlags_IsPacked) {
-        cardinality = "p";
-      } else {
-        cardinality = "r";
-      }
-      break;
-    case kUpb_FieldMode_Scalar:
-      if (mt_f->presence < 0) {
-        cardinality = "o";
-      } else {
-        cardinality = "s";
-      }
-      break;
+  if (upb_MiniTableField_IsArray(mt_f)) {
+    cardinality = upb_MiniTableField_IsPacked(mt_f) ? "p" : "r";
+  } else if (upb_MiniTableField_IsScalar(mt_f)) {
+    cardinality = upb_MiniTableField_IsInOneof(mt_f) ? "o" : "s";
+  } else {
+    return false;  // Not supported yet (ever?).
   }
 
   uint64_t expected_tag = GetEncodedTag(field);
@@ -453,12 +446,12 @@
   }
 
   std::vector<TableEntry> table;
-  uint8_t table_mask = -1;
+  uint8_t table_mask = ~0;
 
   table = FastDecodeTable(message, pools);
 
   if (table.size() > 1) {
-    assert((table.size() & (table.size() - 1)) == 0);
+    UPB_ASSERT((table.size() & (table.size() - 1)) == 0);
     table_mask = (table.size() - 1) << 3;
   }