Simplify the logic for emitting guard variables for template static

data members by delaying the emission of the initializer until after
linkage and visibility have been set on the global.  Also, don't
emit a guard unless the variable actually ends up with vague linkage,
and don't use thread-safe statics in any case.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118336 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 20 deletions

diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index 6567ffb07d..17571fccf0 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -140,9 +140,9 @@ CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *DtorFn,
   Builder.CreateCall(AtExitFn, &Args[0], llvm::array_endof(Args));
 }
 
-void CodeGenFunction::EmitCXXStaticLocalInit(const VarDecl &D,
-                                             llvm::GlobalVariable *DeclPtr) {
-  CGM.getCXXABI().EmitStaticLocalInit(*this, D, DeclPtr);
+void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
+                                         llvm::GlobalVariable *DeclPtr) {
+  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr);
 }
 
 static llvm::Function *
@@ -165,7 +165,8 @@ CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
 }
 
 void
-CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D) {
+CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
+                                            llvm::GlobalVariable *Addr) {
   const llvm::FunctionType *FTy
     = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
                               false);
@@ -174,7 +175,7 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D) {
   llvm::Function *Fn =
     CreateGlobalInitOrDestructFunction(*this, FTy, "__cxx_global_var_init");
 
-  CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D);
+  CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr);
 
   if (D->hasAttr<InitPriorityAttr>()) {
     unsigned int order = D->getAttr<InitPriorityAttr>()->getPriority();
@@ -247,26 +248,20 @@ void CodeGenModule::EmitCXXGlobalDtorFunc() {
   AddGlobalDtor(Fn);
 }
 
+/// Emit the code necessary to initialize the given global variable.
 void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
-                                                       const VarDecl *D) {
+                                                       const VarDecl *D,
+                                                 llvm::GlobalVariable *Addr) {
   StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FunctionArgList(),
                 SourceLocation());
 
-  llvm::Constant *DeclPtr = CGM.GetAddrOfGlobalVar(D);
-  if (D->isStaticDataMember() &&
-      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;
-    }
+  // Use guarded initialization if the global variable is weak due to
+  // being a class template's static data member.
+  if (Addr->hasWeakLinkage() && D->getInstantiatedFromStaticDataMember()) {
+    EmitCXXGuardedInit(*D, Addr);
+  } else {
+    EmitCXXGlobalVarDeclInit(*D, Addr);
   }
-  EmitCXXGlobalVarDeclInit(*D, DeclPtr);
 
   FinishFunction();
 }