From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Sat, 2 Aug 2014 00:50:16 +0000 (+0000)
Subject: In the case of mangling collisions, make an attempt to note both definitions
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=775e4c92e5b72d971111ac35a4e9a5073daa12a3;p=clang

In the case of mangling collisions, make an attempt to note both definitions
involved.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214606 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 08063352f2..8b6aae2161 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -549,9 +549,9 @@ StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
     Str = II->getName();
   }
 
-  auto &Mangled = Manglings.GetOrCreateValue(Str);
-  Mangled.second = GD;
-  return FoundStr = Mangled.first();
+  // Keep the first result in the case of a mangling collision.
+  auto Result = Manglings.insert(std::make_pair(Str, GD));
+  return FoundStr = Result.first->first();
 }
 
 StringRef CodeGenModule::getBlockMangledName(GlobalDecl GD,
@@ -571,9 +571,8 @@ StringRef CodeGenModule::getBlockMangledName(GlobalDecl GD,
   else
     MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Out);
 
-  auto &Mangled = Manglings.GetOrCreateValue(Out.str());
-  Mangled.second = BD;
-  return Mangled.first();
+  auto Result = Manglings.insert(std::make_pair(Out.str(), BD));
+  return Result.first->first();
 }
 
 llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) {
@@ -2192,6 +2191,9 @@ void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
 
   if (!GV->isDeclaration()) {
     getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name);
+    GlobalDecl OldGD = Manglings.lookup(GV->getName());
+    if (auto *Prev = OldGD.getDecl())
+      getDiags().Report(Prev->getLocation(), diag::note_previous_definition);
     return;
   }
 
diff --git a/test/CodeGenCXX/duplicate-mangled-name.cpp b/test/CodeGenCXX/duplicate-mangled-name.cpp
index 65bfa22ac6..e57012e8c4 100644
--- a/test/CodeGenCXX/duplicate-mangled-name.cpp
+++ b/test/CodeGenCXX/duplicate-mangled-name.cpp
@@ -4,7 +4,7 @@
 class MyClass {
  static void meth();
 };
-void MyClass::meth() { }
+void MyClass::meth() { } // expected-note {{previous}}
 extern "C" {
   void _ZN7MyClass4methEv() { } // expected-error {{definition with same mangled name as another definition}}
 }