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Revert "[MS] Don't expect vftables to be provided for extern template instantiations" 

This reverts commit r273296, it broke the Windows self-host.

llvm-svn: 273305
This commit is contained in:
Reid Kleckner 2016-06-21 19:51:52 +00:00
parent 47bd46395a
commit f981bcb3a0
4 changed files with 14 additions and 19 deletions
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13
clang/lib/AST/VTableBuilder.cpp
View File

@ -2545,13 +2545,14 @@ public:
MostDerivedClassLayout(Context.getASTRecordLayout(MostDerivedClass)),
WhichVFPtr(*Which),
Overriders(MostDerivedClass, CharUnits(), MostDerivedClass) {
// Provide the RTTI component if RTTIData is enabled. If the vftable would
// be available externally, we should not provide the RTTI componenent. It
// is currently impossible to get available externally vftables with either
// dllimport or extern template instantiations, but eventually we may add a
// flag to support additional devirtualization that needs this.
// Only include the RTTI component if we know that we will provide a
// definition of the vftable. We always provide the definition of
// dllimported classes.
if (Context.getLangOpts().RTTIData)
HasRTTIComponent = true;
if (MostDerivedClass->hasAttr<DLLImportAttr>() ||
MostDerivedClass->getTemplateSpecializationKind() !=
TSK_ExplicitInstantiationDeclaration)
HasRTTIComponent = true;
LayoutVFTable();

10
clang/lib/CodeGen/CGVTables.cpp
View File

@ -794,10 +794,6 @@ CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) {
return DiscardableODRLinkage;
case TSK_ExplicitInstantiationDeclaration:
// Explicit instantiations in MSVC do not provide vtables, so we must emit
// our own.
if (getTarget().getCXXABI().isMicrosoft())
return DiscardableODRLinkage;
return shouldEmitAvailableExternallyVTable(*this, RD)
? llvm::GlobalVariable::AvailableExternallyLinkage
: llvm::GlobalVariable::ExternalLinkage;
@ -843,9 +839,9 @@ CodeGenVTables::GenerateClassData(const CXXRecordDecl *RD) {
bool CodeGenVTables::isVTableExternal(const CXXRecordDecl *RD) {
assert(RD->isDynamicClass() && "Non-dynamic classes have no VTable.");
// We always synthesize vtables if they are needed in the MS ABI. MSVC doesn't
// emit them even if there is an explicit template instantiation.
if (CGM.getTarget().getCXXABI().isMicrosoft())
// We always synthesize vtables on the import side regardless of whether or
// not it is an explicit instantiation declaration.
if (CGM.getTarget().getCXXABI().isMicrosoft() && RD->hasAttr<DLLImportAttr>())
return false;
// If we have an explicit instantiation declaration (and not a

2
clang/test/CodeGenCXX/microsoft-abi-vbtables.cpp
View File

@ -537,5 +537,5 @@ template <class> struct B : virtual A {
extern template class B<int>;
template B<int>::B();
// CHECK-DAG: @"\01??_8?$B@H@Test30@@7B@" = linkonce_odr unnamed_addr constant [2 x i32] [i32 0, i32 4], comdat
// CHECK-DAG: @"\01??_8?$B@H@Test30@@7B@" = external unnamed_addr constant [2 x i32]{{$}}
}

8
clang/test/CodeGenCXX/microsoft-abi-vftables.cpp
View File

@ -33,7 +33,7 @@ struct __declspec(dllexport) V {
namespace {
struct W {
virtual ~W() {}
virtual ~W();
} w;
}
// RTTI-DAG: [[VTABLE_W:@.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast ({{.*}} @"\01??_R4W@?A@@6B@" to i8*), i8* bitcast ({{.*}} @"\01??_GW@?A@@UAEPAXI@Z" to i8*)]
@ -49,7 +49,5 @@ template <class> struct Y : virtual X {
extern template class Y<int>;
template Y<int>::Y();
// RTTI-DAG: [[VTABLE_Y:@.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast (%rtti.CompleteObjectLocator* @"\01??_R4?$Y@H@@6B@" to i8*), i8* bitcast (i8* (%struct.Y*, i32)* @"\01??_G?$Y@H@@UAEPAXI@Z" to i8*)], comdat($"\01??_7?$Y@H@@6B@")
// RTTI-DAG: @"\01??_7?$Y@H@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* [[VTABLE_Y]], i32 0, i32 1)
// NO-RTTI-DAG: @"\01??_7?$Y@H@@6B@" = linkonce_odr unnamed_addr constant [1 x i8*] [i8* bitcast (i8* (%struct.Y*, i32)* @"\01??_G?$Y@H@@UAEPAXI@Z" to i8*)], comdat
// RTTI-DAG: @"\01??_7?$Y@H@@6B@" = external unnamed_addr constant [1 x i8*]
// NO-RTTI-DAG: @"\01??_7?$Y@H@@6B@" = external unnamed_addr constant [1 x i8*]