[CodeGen] Fix vtable not receiving hidden visibility when using push(visibility)

This change should resolve https://bugs.llvm.org/show_bug.cgi?id=35022

Patch by Jake Ehrlich

Differential Revision: https://reviews.llvm.org/D39627

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@318853 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDecl.cpp

@@ -240,7 +240,7 @@ llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
       getModule(), LTy, Ty.isConstant(getContext()), Linkage, Init, Name,
       nullptr, llvm::GlobalVariable::NotThreadLocal, TargetAS);
   GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
-  setGlobalVisibility(GV, &D);
+  setGlobalVisibility(GV, &D, ForDefinition);
 
   if (supportsCOMDAT() && GV->isWeakForLinker())
     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));

lib/CodeGen/CGVTT.cpp

@@ -100,7 +100,7 @@ CodeGenVTables::EmitVTTDefinition(llvm::GlobalVariable *VTT,
     VTT->setComdat(CGM.getModule().getOrInsertComdat(VTT->getName()));
 
   // Set the right visibility.
-  CGM.setGlobalVisibility(VTT, RD);
+  CGM.setGlobalVisibility(VTT, RD, ForDefinition);
 }
 
 llvm::GlobalVariable *CodeGenVTables::GetAddrOfVTT(const CXXRecordDecl *RD) {

lib/CodeGen/CGVTables.cpp

@@ -51,7 +51,7 @@ llvm::Constant *CodeGenModule::GetAddrOfThunk(GlobalDecl GD,
 
 static void setThunkVisibility(CodeGenModule &CGM, const CXXMethodDecl *MD,
                                const ThunkInfo &Thunk, llvm::Function *Fn) {
-  CGM.setGlobalVisibility(Fn, MD);
+  CGM.setGlobalVisibility(Fn, MD, ForDefinition);
 }
 
 static void setThunkProperties(CodeGenModule &CGM, const ThunkInfo &Thunk,
@@ -730,7 +730,7 @@ CodeGenVTables::GenerateConstructionVTable(const CXXRecordDecl *RD,
   // Create the variable that will hold the construction vtable.
   llvm::GlobalVariable *VTable =
     CGM.CreateOrReplaceCXXRuntimeVariable(Name, VTType, Linkage);
-  CGM.setGlobalVisibility(VTable, RD);
+  CGM.setGlobalVisibility(VTable, RD, ForDefinition);
 
   // V-tables are always unnamed_addr.
   VTable->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);

lib/CodeGen/CodeGenModule.cpp

@@ -662,7 +662,8 @@ llvm::ConstantInt *CodeGenModule::getSize(CharUnits size) {
 }
 
 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
-                                        const NamedDecl *D) const {
+                                        const NamedDecl *D,
+                                        ForDefinition_t IsForDefinition) const {
   // Internal definitions always have default visibility.
   if (GV->hasLocalLinkage()) {
     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
@@ -671,7 +672,8 @@ void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
 
   // Set visibility for definitions.
   LinkageInfo LV = D->getLinkageAndVisibility();
-  if (LV.isVisibilityExplicit() || !GV->hasAvailableExternallyLinkage())
+  if (LV.isVisibilityExplicit() ||
+      (IsForDefinition && !GV->hasAvailableExternallyLinkage()))
     GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
 }
 
@@ -1052,7 +1054,7 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
 void CodeGenModule::SetCommonAttributes(const Decl *D,
                                         llvm::GlobalValue *GV) {
   if (const auto *ND = dyn_cast_or_null<NamedDecl>(D))
-    setGlobalVisibility(GV, ND);
+    setGlobalVisibility(GV, ND, ForDefinition);
   else
     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
 
@@ -1108,8 +1110,8 @@ void CodeGenModule::SetInternalFunctionAttributes(const Decl *D,
   setNonAliasAttributes(D, F);
 }
 
-static void setLinkageAndVisibilityForGV(llvm::GlobalValue *GV,
-                                         const NamedDecl *ND) {
+static void setLinkageForGV(llvm::GlobalValue *GV,
+                            const NamedDecl *ND) {
   // Set linkage and visibility in case we never see a definition.
   LinkageInfo LV = ND->getLinkageAndVisibility();
   if (!isExternallyVisible(LV.getLinkage())) {
@@ -1125,10 +1127,6 @@ static void setLinkageAndVisibilityForGV(llvm::GlobalValue *GV,
       // separate linkage types for this.
       GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
     }
-
-    // Set visibility on a declaration only if it's explicit.
-    if (LV.isVisibilityExplicit())
-      GV->setVisibility(CodeGenModule::GetLLVMVisibility(LV.getVisibility()));
   }
 }
 
@@ -1197,7 +1195,8 @@ void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
   // Only a few attributes are set on declarations; these may later be
   // overridden by a definition.
 
-  setLinkageAndVisibilityForGV(F, FD);
+  setLinkageForGV(F, FD);
+  setGlobalVisibility(F, FD, NotForDefinition);
 
   if (FD->getAttr<PragmaClangTextSectionAttr>()) {
     F->addFnAttr("implicit-section-name");
@@ -2434,7 +2433,8 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
 
     GV->setAlignment(getContext().getDeclAlign(D).getQuantity());
 
-    setLinkageAndVisibilityForGV(GV, D);
+    setLinkageForGV(GV, D);
+    setGlobalVisibility(GV, D, NotForDefinition);
 
     if (D->getTLSKind()) {
       if (D->getTLSKind() == VarDecl::TLS_Dynamic)
@@ -3253,7 +3253,7 @@ void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
   setFunctionDLLStorageClass(GD, Fn);
 
   // FIXME: this is redundant with part of setFunctionDefinitionAttributes
-  setGlobalVisibility(Fn, D);
+  setGlobalVisibility(Fn, D, ForDefinition);
 
   MaybeHandleStaticInExternC(D, Fn);
 
@@ -3849,7 +3849,7 @@ ConstantAddress CodeGenModule::GetAddrOfGlobalTemporary(
       getModule(), Type, Constant, Linkage, InitialValue, Name.c_str(),
       /*InsertBefore=*/nullptr, llvm::GlobalVariable::NotThreadLocal, TargetAS);
   if (emitter) emitter->finalize(GV);
-  setGlobalVisibility(GV, VD);
+  setGlobalVisibility(GV, VD, ForDefinition);
   GV->setAlignment(Align.getQuantity());
   if (supportsCOMDAT() && GV->isWeakForLinker())
     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));

lib/CodeGen/CodeGenModule.h

@@ -710,7 +710,8 @@ public:
   llvm::ConstantInt *getSize(CharUnits numChars);
 
   /// Set the visibility for the given LLVM GlobalValue.
-  void setGlobalVisibility(llvm::GlobalValue *GV, const NamedDecl *D) const;
+  void setGlobalVisibility(llvm::GlobalValue *GV, const NamedDecl *D,
+                           ForDefinition_t IsForDefinition) const;
 
   /// Set the TLS mode for the given LLVM GlobalValue for the thread-local
   /// variable declaration D.

lib/CodeGen/ItaniumCXXABI.cpp

@@ -1527,7 +1527,7 @@ void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
     VTable->setComdat(CGM.getModule().getOrInsertComdat(VTable->getName()));
 
   // Set the right visibility.
-  CGM.setGlobalVisibility(VTable, RD);
+  CGM.setGlobalVisibility(VTable, RD, ForDefinition);
 
   // Use pointer alignment for the vtable. Otherwise we would align them based
   // on the size of the initializer which doesn't make sense as only single
@@ -1637,6 +1637,7 @@ llvm::GlobalVariable *ItaniumCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
   VTable = CGM.CreateOrReplaceCXXRuntimeVariable(
       Name, VTableType, llvm::GlobalValue::ExternalLinkage);
   VTable->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+  CGM.setGlobalVisibility(VTable, RD, NotForDefinition);
 
   if (RD->hasAttr<DLLImportAttr>())
     VTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);

test/CodeGen/push-hidden-visibility-subclass.cpp

@@ -0,0 +1,21 @@
+// RUN: %clang -S -emit-llvm -o %t %s
+// RUN: FileCheck --input-file=%t %s
+
+#pragma GCC visibility push(hidden)
+
+struct Base {
+  virtual ~Base() = default;
+  virtual void* Alloc() = 0;
+};
+
+class Child : public Base {
+public:
+  Child() = default;
+  void* Alloc();
+};
+
+void test() {
+  Child x;
+}
+
+// CHECK: @_ZTV5Child = external hidden unnamed_addr constant