Simplify setting dso_local. NFC.

[• espindola]

Summary

The value of dso_local can be computed from just IR properties and global information (object file type, command line options, etc).

With this patch we no longer pass in the Decl. It was almost unused and making it fully unused guarantees that dso_local is consistent with the rest of the IR.

[echristo]

LGTM. Thanks for the cleanup.

[• espindola]

r325846

lib/CodeGen/CodeGenModule.h

void DecorateInstructionWithInvariantGroup(llvm::Instruction *I,
                                              const CXXRecordDecl *RD);
 
   /// Emit the given number of characters as a value of type size_t.
   llvm::ConstantInt *getSize(CharUnits numChars);
 
   /// Set the visibility for the given LLVM GlobalValue.
   void setGlobalVisibility(llvm::GlobalValue *GV, const NamedDecl *D) const;
 
-  void setDSOLocal(llvm::GlobalValue *GV, const NamedDecl *D) const;
+  void setDSOLocal(llvm::GlobalValue *GV) const;
 
   void setGVProperties(llvm::GlobalValue *GV, const NamedDecl *D) const;
 
   /// Set the TLS mode for the given LLVM GlobalValue for the thread-local
   /// variable declaration D.
   void setTLSMode(llvm::GlobalValue *GV, const VarDecl &D) const;
 
   static llvm::GlobalValue::VisibilityTypes GetLLVMVisibility(Visibility V) {

lib/CodeGen/CodeGenModule.cpp

void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
 
   // Set visibility for definitions.
   LinkageInfo LV = D->getLinkageAndVisibility();
   if (LV.isVisibilityExplicit() || !GV->isDeclarationForLinker())
     GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
 }
 
 static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
-                                 llvm::GlobalValue *GV, const NamedDecl *D) {
+                                 llvm::GlobalValue *GV) {
   const llvm::Triple &TT = CGM.getTriple();
   // Only handle ELF for now.
   if (!TT.isOSBinFormatELF())
     return false;
 
   // If this is not an executable, don't assume anything is local.
   const auto &CGOpts = CGM.getCodeGenOpts();
   llvm::Reloc::Model RM = CGOpts.RelocationModel;
static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
 
   // PPC has no copy relocations and cannot use a plt entry as a symbol address.
   llvm::Triple::ArchType Arch = TT.getArch();
   if (Arch == llvm::Triple::ppc || Arch == llvm::Triple::ppc64 ||
       Arch == llvm::Triple::ppc64le)
     return false;
 
   // If we can use copy relocations we can assume it is local.
-  if (auto *VD = dyn_cast<VarDecl>(D))
-    if (VD->getTLSKind() == VarDecl::TLS_None &&
+  if (auto *Var = dyn_cast<llvm::GlobalVariable>(GV))
+    if (!Var->isThreadLocal() &&
         (RM == llvm::Reloc::Static || CGOpts.PIECopyRelocations))
       return true;
 
   // If we can use a plt entry as the symbol address we can assume it
   // is local.
   // FIXME: This should work for PIE, but the gold linker doesn't support it.
-  if (isa<FunctionDecl>(D) && !CGOpts.NoPLT && RM == llvm::Reloc::Static)
+  if (isa<llvm::Function>(GV) && !CGOpts.NoPLT && RM == llvm::Reloc::Static)
     return true;
 
   // Otherwise don't assue it is local.
   return false;
 }
 
-void CodeGenModule::setDSOLocal(llvm::GlobalValue *GV,
-                                const NamedDecl *D) const {
-  if (shouldAssumeDSOLocal(*this, GV, D))
+void CodeGenModule::setDSOLocal(llvm::GlobalValue *GV) const {
+  if (shouldAssumeDSOLocal(*this, GV))
     GV->setDSOLocal(true);
 }
 
 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
                                     const NamedDecl *D) const {
   setGlobalVisibility(GV, D);
-  setDSOLocal(GV, D);
+  setDSOLocal(GV);
 }
 
 static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel(StringRef S) {
   return llvm::StringSwitch<llvm::GlobalVariable::ThreadLocalMode>(S)
       .Case("global-dynamic", llvm::GlobalVariable::GeneralDynamicTLSModel)
       .Case("local-dynamic", llvm::GlobalVariable::LocalDynamicTLSModel)
       .Case("initial-exec", llvm::GlobalVariable::InitialExecTLSModel)
       .Case("local-exec", llvm::GlobalVariable::LocalExecTLSModel);
CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
   if (D) {
     // FIXME: This code is overly simple and should be merged with other global
     // handling.
     GV->setConstant(isTypeConstant(D->getType(), false));
 
     GV->setAlignment(getContext().getDeclAlign(D).getQuantity());
 
     setLinkageForGV(GV, D);
-    setGVProperties(GV, D);
 
     if (D->getTLSKind()) {
       if (D->getTLSKind() == VarDecl::TLS_Dynamic)
         CXXThreadLocals.push_back(D);
       setTLSMode(GV, *D);
     }
 
+    setGVProperties(GV, D);
+
     // If required by the ABI, treat declarations of static data members with
     // inline initializers as definitions.
     if (getContext().isMSStaticDataMemberInlineDefinition(D)) {
       EmitGlobalVarDefinition(D);
     }
 
     // Emit section information for extern variables.
     if (D->hasExternalStorage()) {

lib/CodeGen/ItaniumCXXABI.cpp

if (llvm::GlobalValue::isLocalLinkage(Linkage))
     // If the linkage is local, only default visibility makes sense.
     llvmVisibility = llvm::GlobalValue::DefaultVisibility;
   else if (RTTIUniqueness == ItaniumCXXABI::RUK_NonUniqueHidden)
     llvmVisibility = llvm::GlobalValue::HiddenVisibility;
   else
     llvmVisibility = CodeGenModule::GetLLVMVisibility(Ty->getVisibility());
 
   TypeName->setVisibility(llvmVisibility);
-  CGM.setDSOLocal(TypeName, Ty->getAsCXXRecordDecl());
+  CGM.setDSOLocal(TypeName);
 
   GV->setVisibility(llvmVisibility);
-  CGM.setDSOLocal(GV, Ty->getAsCXXRecordDecl());
+  CGM.setDSOLocal(GV);
 
   if (CGM.getTriple().isWindowsItaniumEnvironment()) {
     auto RD = Ty->getAsCXXRecordDecl();
     if (DLLExport || (RD && RD->hasAttr<DLLExportAttr>())) {
       TypeName->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
       GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
     } else if (RD && RD->hasAttr<DLLImportAttr>() &&
                ShouldUseExternalRTTIDescriptor(CGM, Ty)) {