commit 5a3d4840019a62c615e949cf28f2c610c2a88387
author Nathan Sidwell <nathan@acm.org> Tue Apr 05 09:25:47 2022 -0700
committer Copybara-Service <copybara-worker@google.com> Wed Apr 06 10:30:50 2022 -0700
tree 25b3037585a60bf5169857841193d7b4963362a4
parent 166054f70b0b4da427f91202032e4034264105e1

[demangler] Fix undocumented Local encoding

GCC emits [some] static symbols with an 'L' mangling, which we attempt
to demangle.  But the module mangling changes have exposed that we
were doing so at the wrong level.  Such manglings are outside of the
ABI as they are internal-linkage, so a bit of reverse engineering was
needed.  This adjusts the demangler along the same lines as the
existing gcc demangler (which is not yet module-aware).  'L' is part
of an unqualified name.  As before we merely parse the 'L', and then
ignore it.

Reviewed By: iains

Differential Revision: https://reviews.llvm.org/D123138

GitOrigin-RevId: df4522feb790ea574f470e45e473aac1f6483b93

src/demangle/ItaniumDemangle.h

diff --git a/src/demangle/ItaniumDemangle.h b/src/demangle/ItaniumDemangle.h
index 9a0b9bf..fd6835a 100644
--- a/src/demangle/ItaniumDemangle.h
+++ b/src/demangle/ItaniumDemangle.h
@@ -2729,8 +2729,8 @@
   return make<LocalName>(Encoding, Entity);
 }
 
-// <unscoped-name> ::= [L]* <unqualified-name>
-//                 ::= St [L]* <unqualified-name>   # ::std::
+// <unscoped-name> ::= <unqualified-name>
+//                 ::= St <unqualified-name>   # ::std::
 // [*] extension
 template <typename Derived, typename Alloc>
 Node *
@@ -2743,7 +2743,6 @@
     if (Std == nullptr)
       return nullptr;
   }
-  consumeIf('L');
 
   Node *Res = nullptr;
   ModuleName *Module = nullptr;
@@ -2761,29 +2760,32 @@
     }
   }
 
-  if (Res == nullptr)
+  if (Res == nullptr || Std != nullptr) {
     Res = getDerived().parseUnqualifiedName(State, Std, Module);
+  }
 
   return Res;
 }
 
-// <unqualified-name> ::= [<module-name>] <operator-name> [<abi-tags>]
+// <unqualified-name> ::= [<module-name>] L? <operator-name> [<abi-tags>]
 //                    ::= [<module-name>] <ctor-dtor-name> [<abi-tags>]
-//                    ::= [<module-name>] <source-name> [<abi-tags>]
-//                    ::= [<module-name>] <unnamed-type-name> [<abi-tags>]
+//                    ::= [<module-name>] L? <source-name> [<abi-tags>]
+//                    ::= [<module-name>] L? <unnamed-type-name> [<abi-tags>]
 //			# structured binding declaration
-//                    ::= [<module-name>] DC <source-name>+ E
+//                    ::= [<module-name>] L? DC <source-name>+ E
 template <typename Derived, typename Alloc>
 Node *AbstractManglingParser<Derived, Alloc>::parseUnqualifiedName(
     NameState *State, Node *Scope, ModuleName *Module) {
   if (getDerived().parseModuleNameOpt(Module))
     return nullptr;
 
+  consumeIf('L');
+
   Node *Result;
-  if (look() == 'U') {
-    Result = getDerived().parseUnnamedTypeName(State);
-  } else if (look() >= '1' && look() <= '9') {
+  if (look() >= '1' && look() <= '9') {
     Result = getDerived().parseSourceName(State);
+  } else if (look() == 'U') {
+    Result = getDerived().parseUnnamedTypeName(State);
   } else if (consumeIf("DC")) {
     // Structured binding
     size_t BindingsBegin = Names.size();
@@ -3163,10 +3165,12 @@
   return nullptr;
 }
 
-// <nested-name> ::= N [<CV-Qualifiers>] [<ref-qualifier>] <prefix> <unqualified-name> E
-//               ::= N [<CV-Qualifiers>] [<ref-qualifier>] <template-prefix> <template-args> E
+// <nested-name> ::= N [<CV-Qualifiers>] [<ref-qualifier>] <prefix>
+// 			<unqualified-name> E
+//               ::= N [<CV-Qualifiers>] [<ref-qualifier>] <template-prefix>
+//               	<template-args> E
 //
-// <prefix> ::= <prefix> [L]* <unqualified-name>
+// <prefix> ::= <prefix> <unqualified-name>
 //          ::= <template-prefix> <template-args>
 //          ::= <template-param>
 //          ::= <decltype>
@@ -3230,7 +3234,6 @@
       SoFar = getDerived().parseDecltype();
     } else {
       ModuleName *Module = nullptr;
-      bool IsLocal = consumeIf('L'); // extension
 
       if (look() == 'S') {
         //          ::= <substitution>
@@ -3245,7 +3248,7 @@
           return nullptr;
         if (S->getKind() == Node::KModuleName) {
           Module = static_cast<ModuleName *>(S);
-        } else if (SoFar != nullptr || IsLocal) {
+        } else if (SoFar != nullptr) {
           return nullptr; // Cannot have a prefix.
         } else {
           SoFar = S;

test/test_demangle.pass.cpp

diff --git a/test/test_demangle.pass.cpp b/test/test_demangle.pass.cpp
index 1ba6170..5282b01 100644
--- a/test/test_demangle.pass.cpp
+++ b/test/test_demangle.pass.cpp
@@ -30078,6 +30078,8 @@
     {"_ZGIW3Foo", "initializer for module Foo"},
     {"_ZGIW3FooW3Bar", "initializer for module Foo.Bar"},
     {"_ZGIW3FooWP3BarW3Baz", "initializer for module Foo:Bar.Baz"},
+    {"_ZW1ML4Oink", "Oink@M"},
+    {"_ZW1ML1fi", "f@M(int)"},
 };
 
 const unsigned N = sizeof(cases) / sizeof(cases[0]);