CodeGen: Mark functions used in vtables as unnamed_addr.

This marks virtual function declarations, as well as runtime library functions
__cxa_pure_virtual, __cxa_deleted_virtual and _purecall, as unnamed_addr. This
will allow us to correctly form relative references to them from vtables in
the relative vtable ABI.

Differential Revision: http://reviews.llvm.org/D18071

llvm-svn: 263464

clang/lib/CodeGen/CGVTables.cpp

@@ -607,6 +607,8 @@ llvm::Constant *CodeGenVTables::CreateVTableInitializer(
             llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
           StringRef PureCallName = CGM.getCXXABI().GetPureVirtualCallName();
           PureVirtualFn = CGM.CreateRuntimeFunction(Ty, PureCallName);
+          if (auto *F = dyn_cast<llvm::Function>(PureVirtualFn))
+            F->setUnnamedAddr(true);
           PureVirtualFn = llvm::ConstantExpr::getBitCast(PureVirtualFn,
                                                          CGM.Int8PtrTy);
         }
@@ -618,6 +620,8 @@ llvm::Constant *CodeGenVTables::CreateVTableInitializer(
           StringRef DeletedCallName =
             CGM.getCXXABI().GetDeletedVirtualCallName();
           DeletedVirtualFn = CGM.CreateRuntimeFunction(Ty, DeletedCallName);
+          if (auto *F = dyn_cast<llvm::Function>(DeletedVirtualFn))
+            F->setUnnamedAddr(true);
           DeletedVirtualFn = llvm::ConstantExpr::getBitCast(DeletedVirtualFn,
                                                          CGM.Int8PtrTy);
         }

clang/lib/CodeGen/CodeGenModule.cpp

@@ -906,12 +906,6 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
     F->removeFnAttr(llvm::Attribute::InlineHint);
   }
 
-  if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D))
-    F->setUnnamedAddr(true);
-  else if (const auto *MD = dyn_cast<CXXMethodDecl>(D))
-    if (MD->isVirtual())
-      F->setUnnamedAddr(true);
-
   unsigned alignment = D->getMaxAlignment() / Context.getCharWidth();
   if (alignment)
     F->setAlignment(alignment);
@@ -1079,6 +1073,12 @@ void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
     F->addAttribute(llvm::AttributeSet::FunctionIndex,
                     llvm::Attribute::NoBuiltin);
 
+  if (isa<CXXConstructorDecl>(FD) || isa<CXXDestructorDecl>(FD))
+    F->setUnnamedAddr(true);
+  else if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
+    if (MD->isVirtual())
+      F->setUnnamedAddr(true);
+
   CreateFunctionBitSetEntry(FD, F);
 }
 

clang/test/CodeGenCXX/virtual-function-attrs.cpp

@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 %s -triple %itanium_abi_triple -std=c++11 -emit-llvm -o - | FileCheck %s
+
+class A {
+  virtual void f();
+  virtual void g();
+  virtual ~A();
+};
+
+void A::f() {}
+
+// CHECK: define void @_ZN1A1fEv({{.*}}) unnamed_addr
+// CHECK: declare void @_ZN1A1gEv({{.*}}) unnamed_addr
+// CHECK: declare void @_ZN1AD1Ev({{.*}}) unnamed_addr
+// CHECK: declare void @_ZN1AD0Ev({{.*}}) unnamed_addr

clang/test/CodeGenCXX/vtt-layout.cpp

@@ -84,3 +84,5 @@ namespace Test6 {
 // CHECK: @_ZTTN5Test21CE = linkonce_odr unnamed_addr constant [2 x i8*] [i8* bitcast (i8** getelementptr inbounds ([5 x i8*], [5 x i8*]* @_ZTVN5Test21CE, i64 0, i64 4) to i8*), i8* bitcast (i8** getelementptr inbounds ([5 x i8*], [5 x i8*]* @_ZTVN5Test21CE, i64 0, i64 4) to i8*)] 
 // CHECK: @_ZTTN5Test31DE = linkonce_odr unnamed_addr constant [13 x i8*] [i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTVN5Test31DE, i64 0, i64 5) to i8*), i8* bitcast (i8** getelementptr inbounds ([7 x i8*], [7 x i8*]* @_ZTCN5Test31DE0_NS_2C1E, i64 0, i64 3) to i8*), i8* bitcast (i8** getelementptr inbounds ([7 x i8*], [7 x i8*]* @_ZTCN5Test31DE0_NS_2C1E, i64 0, i64 6) to i8*), i8* bitcast (i8** getelementptr inbounds ([14 x i8*], [14 x i8*]* @_ZTCN5Test31DE16_NS_2C2E, i64 0, i64 6) to i8*), i8* bitcast (i8** getelementptr inbounds ([14 x i8*], [14 x i8*]* @_ZTCN5Test31DE16_NS_2C2E, i64 0, i64 6) to i8*), i8* bitcast (i8** getelementptr inbounds ([14 x i8*], [14 x i8*]* @_ZTCN5Test31DE16_NS_2C2E, i64 0, i64 10) to i8*), i8* bitcast (i8** getelementptr inbounds ([14 x i8*], [14 x i8*]* @_ZTCN5Test31DE16_NS_2C2E, i64 0, i64 13) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTVN5Test31DE, i64 0, i64 15) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTVN5Test31DE, i64 0, i64 11) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTVN5Test31DE, i64 0, i64 11) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTVN5Test31DE, i64 1, i64 0) to i8*), i8* bitcast (i8** getelementptr inbounds ([7 x i8*], [7 x i8*]* @_ZTCN5Test31DE64_NS_2V2E, i64 0, i64 3) to i8*), i8* bitcast (i8** getelementptr inbounds ([7 x i8*], [7 x i8*]* @_ZTCN5Test31DE64_NS_2V2E, i64 0, i64 6) to i8*)] 
 // CHECK: @_ZTTN5Test41DE = linkonce_odr unnamed_addr constant [19 x i8*] [i8* bitcast (i8** getelementptr inbounds ([25 x i8*], [25 x i8*]* @_ZTVN5Test41DE, i64 0, i64 6) to i8*), i8* bitcast (i8** getelementptr inbounds ([11 x i8*], [11 x i8*]* @_ZTCN5Test41DE0_NS_2C1E, i64 0, i64 4) to i8*), i8* bitcast (i8** getelementptr inbounds ([11 x i8*], [11 x i8*]* @_ZTCN5Test41DE0_NS_2C1E, i64 0, i64 7) to i8*), i8* bitcast (i8** getelementptr inbounds ([11 x i8*], [11 x i8*]* @_ZTCN5Test41DE0_NS_2C1E, i64 0, i64 10) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTCN5Test41DE16_NS_2C2E, i64 0, i64 7) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTCN5Test41DE16_NS_2C2E, i64 0, i64 7) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTCN5Test41DE16_NS_2C2E, i64 0, i64 12) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTCN5Test41DE16_NS_2C2E, i64 0, i64 15) to i8*), i8* bitcast (i8** getelementptr inbounds ([19 x i8*], [19 x i8*]* @_ZTCN5Test41DE16_NS_2C2E, i64 0, i64 18) to i8*), i8* bitcast (i8** getelementptr inbounds ([25 x i8*], [25 x i8*]* @_ZTVN5Test41DE, i64 0, i64 17) to i8*), i8* bitcast (i8** getelementptr inbounds ([25 x i8*], [25 x i8*]* @_ZTVN5Test41DE, i64 0, i64 20) to i8*), i8* bitcast (i8** getelementptr inbounds ([25 x i8*], [25 x i8*]* @_ZTVN5Test41DE, i64 0, i64 13) to i8*), i8* bitcast (i8** getelementptr inbounds ([25 x i8*], [25 x i8*]* @_ZTVN5Test41DE, i64 0, i64 13) to i8*), i8* bitcast (i8** getelementptr inbounds ([25 x i8*], [25 x i8*]* @_ZTVN5Test41DE, i64 1, i64 0) to i8*), i8* bitcast (i8** getelementptr inbounds ([7 x i8*], [7 x i8*]* @_ZTCN5Test41DE40_NS_2V1E, i64 0, i64 3) to i8*), i8* bitcast (i8** getelementptr inbounds ([7 x i8*], [7 x i8*]* @_ZTCN5Test41DE40_NS_2V1E, i64 0, i64 6) to i8*), i8* bitcast (i8** getelementptr inbounds ([11 x i8*], [11 x i8*]* @_ZTCN5Test41DE72_NS_2V2E, i64 0, i64 4) to i8*), i8* bitcast (i8** getelementptr inbounds ([11 x i8*], [11 x i8*]* @_ZTCN5Test41DE72_NS_2V2E, i64 0, i64 7) to i8*), i8* bitcast (i8** getelementptr inbounds ([11 x i8*], [11 x i8*]* @_ZTCN5Test41DE72_NS_2V2E, i64 0, i64 10) to i8*)] 
+// CHECK: declare void @__cxa_pure_virtual() unnamed_addr
+// CHECK: declare void @__cxa_deleted_virtual() unnamed_addr