Do the guarding of instantiated static data members

on if its linkage is weak. Currently this is the
case but may change in the future. (part of radar 
8562966).

llvm-svn: 117452

clang/lib/CodeGen/CGDeclCXX.cpp

@@ -257,10 +257,15 @@ void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
       D->getInstantiatedFromStaticDataMember() && D->getInit()){
     llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(DeclPtr);
     assert(GV && "GenerateCXXGlobalVarDeclInitFunc - GV is null");
+    llvm::GlobalValue::LinkageTypes Linkage = 
+      CGM.GetLLVMLinkageVarDefinition(D, GV);
+    if (Linkage == llvm::GlobalVariable::WeakAnyLinkage) {
       GV->setConstant(false);
       EmitCXXStaticLocalInit(*D, GV);
+      FinishFunction();
+      return;
+    }
   }
-  else
   EmitCXXGlobalVarDeclInit(*D, DeclPtr);
 
   FinishFunction();

clang/lib/CodeGen/CodeGenModule.cpp

@@ -1156,32 +1156,12 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   GV->setAlignment(getContext().getDeclAlign(D).getQuantity());
   
   // Set the llvm linkage type as appropriate.
-  GVALinkage Linkage = getContext().GetGVALinkageForVariable(D);
-  if (Linkage == GVA_Internal)
-    GV->setLinkage(llvm::Function::InternalLinkage);
-  else if (D->hasAttr<DLLImportAttr>())
-    GV->setLinkage(llvm::Function::DLLImportLinkage);
-  else if (D->hasAttr<DLLExportAttr>())
-    GV->setLinkage(llvm::Function::DLLExportLinkage);
-  else if (D->hasAttr<WeakAttr>()) {
-    if (GV->isConstant())
-      GV->setLinkage(llvm::GlobalVariable::WeakODRLinkage);
-    else
-      GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
-  } else if (Linkage == GVA_TemplateInstantiation ||
-             Linkage == GVA_ExplicitTemplateInstantiation)
-    // FIXME: It seems like we can provide more specific linkage here
-    // (LinkOnceODR, WeakODR).
-    GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);   
-  else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon &&
-           !D->hasExternalStorage() && !D->getInit() &&
-           !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) {
-    // Thread local vars aren't considered common linkage.
-    GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
+  llvm::GlobalValue::LinkageTypes Linkage = 
+    GetLLVMLinkageVarDefinition(D, GV);
+  GV->setLinkage(Linkage);
+  if (Linkage == llvm::GlobalVariable::CommonLinkage)
     // common vars aren't constant even if declared const.
     GV->setConstant(false);
-  } else
-    GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
 
   SetCommonAttributes(D, GV);
 
@@ -1192,6 +1172,35 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   }
 }
 
+llvm::GlobalValue::LinkageTypes
+CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D,
+                                           llvm::GlobalVariable *GV) {
+  GVALinkage Linkage = getContext().GetGVALinkageForVariable(D);
+  if (Linkage == GVA_Internal)
+    return llvm::Function::InternalLinkage;
+  else if (D->hasAttr<DLLImportAttr>())
+    return llvm::Function::DLLImportLinkage;
+  else if (D->hasAttr<DLLExportAttr>())
+    return llvm::Function::DLLExportLinkage;
+  else if (D->hasAttr<WeakAttr>()) {
+    if (GV->isConstant())
+      return llvm::GlobalVariable::WeakODRLinkage;
+    else
+      return llvm::GlobalVariable::WeakAnyLinkage;
+  } else if (Linkage == GVA_TemplateInstantiation ||
+             Linkage == GVA_ExplicitTemplateInstantiation)
+    // FIXME: It seems like we can provide more specific linkage here
+    // (LinkOnceODR, WeakODR).
+    return llvm::GlobalVariable::WeakAnyLinkage;
+  else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon &&
+           !D->hasExternalStorage() && !D->getInit() &&
+           !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) {
+    // Thread local vars aren't considered common linkage.
+    return llvm::GlobalVariable::CommonLinkage;
+  }
+  return llvm::GlobalVariable::ExternalLinkage;
+}
+
 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
 /// implement a function with no prototype, e.g. "int foo() {}".  If there are
 /// existing call uses of the old function in the module, this adjusts them to

clang/lib/CodeGen/CodeGenModule.h

@@ -512,6 +512,12 @@ public:
   /// the given LLVM type.
   CharUnits GetTargetTypeStoreSize(const llvm::Type *Ty) const;
   
+  /// GetLLVMLinkageVarDefinition - Returns LLVM linkage for a global 
+  /// variable.
+  llvm::GlobalValue::LinkageTypes 
+  GetLLVMLinkageVarDefinition(const VarDecl *D,
+                              llvm::GlobalVariable *GV);
+  
   std::vector<const CXXRecordDecl*> DeferredVTables;
 
 private: