Revert r236879, "Do not emit thunks with available_externally linkage in comdats"

It broke pecoff, at least i686-cygwin.

llvm-svn: 236937

1 files changed, 11 insertions, 12 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index b3d7b5d4f6d..d75dcd22134 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1298,7 +1298,8 @@ llvm::Constant *CodeGenModule::GetAddrOfUuidDescriptor(
   auto *GV = new llvm::GlobalVariable(
       getModule(), Init->getType(),
       /*isConstant=*/true, llvm::GlobalValue::LinkOnceODRLinkage, Init, Name);
-  maybeSetTrivialComdat(*GV);
+  if (supportsCOMDAT())
+    GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
   return GV;
 }
 
@@ -1849,7 +1850,9 @@ CodeGenModule::CreateOrReplaceCXXRuntimeVariable(StringRef Name,
     OldGV->eraseFromParent();
   }
 
-  maybeSetTrivialComdat(*GV);
+  if (supportsCOMDAT() && GV->isWeakForLinker() &&
+      !GV->hasAvailableExternallyLinkage())
+    GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
 
   return GV;
 }
@@ -1982,14 +1985,6 @@ void CodeGenModule::maybeSetTrivialComdat(const Decl &D,
   GO.setComdat(TheModule.getOrInsertComdat(GO.getName()));
 }
 
-void CodeGenModule::maybeSetTrivialComdat(llvm::GlobalObject &GO) {
-  if (!supportsCOMDAT())
-    return;
-  if (GO.isWeakForLinker() && !GO.hasAvailableExternallyLinkage()) {
-    GO.setComdat(getModule().getOrInsertComdat(GO.getName()));
-  }
-}
-
 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   llvm::Constant *Init = nullptr;
   QualType ASTTy = D->getType();
@@ -2929,7 +2924,10 @@ GenerateStringLiteral(llvm::Constant *C, llvm::GlobalValue::LinkageTypes LT,
       nullptr, llvm::GlobalVariable::NotThreadLocal, AddrSpace);
   GV->setAlignment(Alignment);
   GV->setUnnamedAddr(true);
-  CGM.maybeSetTrivialComdat(*GV);
+  if (GV->isWeakForLinker()) {
+    assert(CGM.supportsCOMDAT() && "Only COFF uses weak string literals");
+    GV->setComdat(M.getOrInsertComdat(GV->getName()));
+  }
 
   return GV;
 }
@@ -3111,7 +3109,8 @@ llvm::Constant *CodeGenModule::GetAddrOfGlobalTemporary(
   setGlobalVisibility(GV, VD);
   GV->setAlignment(
       getContext().getTypeAlignInChars(MaterializedType).getQuantity());
-  maybeSetTrivialComdat(*GV);
+  if (supportsCOMDAT() && GV->isWeakForLinker())
+    GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
   if (VD->getTLSKind())
     setTLSMode(GV, *VD);
   Slot = GV;