Produce direct calls instead of alias to linkonce_odr functions.
This is a small optimization on linux, but should help more on windows
where msvc only outputs one destructor if there would be two identical ones.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194046 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index 25f3e6f..ab45e32 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -112,28 +112,13 @@
// support aliases with that linkage, fail.
llvm::GlobalValue::LinkageTypes Linkage = getFunctionLinkage(AliasDecl);
- llvm::GlobalValue::LinkageTypes TargetLinkage
- = getFunctionLinkage(TargetDecl);
-
- // Don't create an alias to a linker weak symbol unless we know we can do
- // that in every TU. This avoids producing different COMDATs in different
- // TUs.
- if (llvm::GlobalValue::isWeakForLinker(TargetLinkage)) {
- if (!InEveryTU)
- return true;
-
- // In addition to making sure we produce it in every TU, we have to make
- // sure llvm keeps it.
- // FIXME: Instead of outputting an alias we could just replace every use of
- // AliasDecl with TargetDecl.
- assert(Linkage == TargetLinkage);
- Linkage = llvm::GlobalValue::WeakODRLinkage;
- }
-
// We can't use an alias if the linkage is not valid for one.
if (!llvm::GlobalAlias::isValidLinkage(Linkage))
return true;
+ llvm::GlobalValue::LinkageTypes TargetLinkage =
+ getFunctionLinkage(TargetDecl);
+
// Check if we have it already.
StringRef MangledName = getMangledName(AliasDecl);
llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
@@ -152,6 +137,26 @@
if (Ref->getType() != AliasType)
Aliasee = llvm::ConstantExpr::getBitCast(Ref, AliasType);
+ // Don't create an alias to a linker weak symbol unless we know we can do
+ // that in every TU. This avoids producing different COMDATs in different
+ // TUs.
+ if (llvm::GlobalValue::isWeakForLinker(TargetLinkage)) {
+ if (!InEveryTU)
+ return true;
+
+ assert(Linkage == TargetLinkage);
+ // Instead of creating as alias to a linkonce_odr, replace all of the uses
+ // of the aliassee.
+ if (TargetLinkage == llvm::GlobalValue::LinkOnceODRLinkage) {
+ if (!Entry)
+ return false;
+
+ Entry->replaceAllUsesWith(Aliasee);
+ Entry->eraseFromParent();
+ return false;
+ }
+ }
+
// Create the alias with no name.
llvm::GlobalAlias *Alias =
new llvm::GlobalAlias(AliasType, Linkage, "", Aliasee, &getModule());