From 35ab328e942259b6ebb75785f54abbfdf6f50d93 Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Wed, 11 Jun 2014 04:08:55 +0000 Subject: CodeGen: Correct linkage of thread_local for OS X The backing store of thread local variables is internal for OS X and all accesses must go through the thread wrapper. However, individual TUs may have inlined through the thread wrapper. To fix this, give the thread wrapper functions WeakAnyLinkage. This prevents them from getting inlined into call-sites. This fixes PR19989. llvm-svn: 210632 --- clang/lib/CodeGen/CodeGenModule.cpp | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'clang/lib/CodeGen/CodeGenModule.cpp') diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index b2d87db4880..79338787966 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -1903,6 +1903,16 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { // Set the llvm linkage type as appropriate. llvm::GlobalValue::LinkageTypes Linkage = getLLVMLinkageVarDefinition(D, GV->isConstant()); + + // On Darwin, the backing variable for a C++11 thread_local variable always + // has internal linkage; all accesses should just be calls to the + // Itanium-specified entry point, which has the normal linkage of the + // variable. + if (const auto *VD = dyn_cast(D)) + if (!VD->isStaticLocal() && VD->getTLSKind() == VarDecl::TLS_Dynamic && + Context.getTargetInfo().getTriple().isMacOSX()) + Linkage = llvm::GlobalValue::InternalLinkage; + GV->setLinkage(Linkage); if (D->hasAttr()) GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass); -- cgit v1.2.3