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authorRafael Espindola <rafael.espindola@gmail.com>2010-03-04 18:17:24 +0000
committerRafael Espindola <rafael.espindola@gmail.com>2010-03-04 18:17:24 +0000
commit2e42fec3a092692a98865cb264940e9320c42aa0 (patch)
tree3ad73e79deaacd19dc9bef42463727e396823377 /clang/lib/CodeGen/CodeGenModule.cpp
parent334db0ce7f2fc39f4644dd50e878f467a2a0f89b (diff)
downloadbcm5719-llvm-2e42fec3a092692a98865cb264940e9320c42aa0.tar.gz
bcm5719-llvm-2e42fec3a092692a98865cb264940e9320c42aa0.zip
Fix PR6473.
Clang's support for weakref is now better than llvm-gcc's :-) We don't introduce a new symbol and we correctly mark undefined references weak only if there is no definition or regular undefined references in the same file. llvm-svn: 97733
Diffstat (limited to 'clang/lib/CodeGen/CodeGenModule.cpp')
-rw-r--r--clang/lib/CodeGen/CodeGenModule.cpp47
1 files changed, 47 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index bc2bd6c882d..e6e9b1a595e 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -619,9 +619,41 @@ bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) {
return false;
}
+llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
+ const AliasAttr *AA = VD->getAttr<AliasAttr>();
+ assert(AA && "No alias?");
+
+ const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
+
+ // Unique the name through the identifier table.
+ const char *AliaseeName =
+ getContext().Idents.get(AA->getAliasee()).getNameStart();
+
+ // See if there is already something with the target's name in the module.
+ llvm::GlobalValue *Entry = GlobalDeclMap[AliaseeName];
+
+ llvm::Constant *Aliasee;
+ if (isa<llvm::FunctionType>(DeclTy))
+ Aliasee = GetOrCreateLLVMFunction(AliaseeName, DeclTy, GlobalDecl());
+ else
+ Aliasee = GetOrCreateLLVMGlobal(AliaseeName,
+ llvm::PointerType::getUnqual(DeclTy), 0);
+ if (!Entry) {
+ llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee);
+ F->setLinkage(llvm::Function::ExternalWeakLinkage);
+ WeakRefReferences.insert(F);
+ }
+
+ return Aliasee;
+}
+
void CodeGenModule::EmitGlobal(GlobalDecl GD) {
const ValueDecl *Global = cast<ValueDecl>(GD.getDecl());
+ // Weak references don't produce any output by themselves.
+ if (Global->hasAttr<WeakRefAttr>())
+ return;
+
// If this is an alias definition (which otherwise looks like a declaration)
// emit it now.
if (Global->hasAttr<AliasAttr>())
@@ -708,6 +740,14 @@ llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(const char *MangledName,
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
if (Entry) {
+ if (WeakRefReferences.count(Entry)) {
+ const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl());
+ if (FD && !FD->hasAttr<WeakAttr>())
+ Entry->setLinkage(llvm::Function::ExternalLinkage);
+
+ WeakRefReferences.erase(Entry);
+ }
+
if (Entry->getType()->getElementType() == Ty)
return Entry;
@@ -817,6 +857,13 @@ llvm::Constant *CodeGenModule::GetOrCreateLLVMGlobal(const char *MangledName,
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
if (Entry) {
+ if (WeakRefReferences.count(Entry)) {
+ if (D && !D->hasAttr<WeakAttr>())
+ Entry->setLinkage(llvm::Function::ExternalLinkage);
+
+ WeakRefReferences.erase(Entry);
+ }
+
if (Entry->getType() == Ty)
return Entry;
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