From: David Majnemer Date: Thu, 11 Feb 2016 17:49:28 +0000 (+0000) Subject: Revert "Revert r260388 "[MS ABI] Never reference dllimport'd vtables"" X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ce1b4d57a6c849757f7ac7ab26dbaebcc485f1ae;p=clang Revert "Revert r260388 "[MS ABI] Never reference dllimport'd vtables"" This reverts commit r260449. We would supress our emission of vftable definitions if we thought another translation unit would provide the definition because we saw an explicit instantiation declaration. This is not the case with dllimport, we want to synthesize a definition of the vftable regardless. This fixes PR26569. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@260548 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/AST/MicrosoftMangle.cpp b/lib/AST/MicrosoftMangle.cpp index 0634319cbd..930cf00d9e 100644 --- a/lib/AST/MicrosoftMangle.cpp +++ b/lib/AST/MicrosoftMangle.cpp @@ -2599,7 +2599,10 @@ void MicrosoftMangleContextImpl::mangleCXXVFTable( // NOTE: here is always 'B' (const). // is always '6' for vftables. MicrosoftCXXNameMangler Mangler(*this, Out); - Mangler.getStream() << "\01??_7"; + if (Derived->hasAttr()) + Mangler.getStream() << "\01??_S"; + else + Mangler.getStream() << "\01??_7"; Mangler.mangleName(Derived); Mangler.getStream() << "6B"; // '6' for vftable, 'B' for const. for (const CXXRecordDecl *RD : BasePath) diff --git a/lib/AST/VTableBuilder.cpp b/lib/AST/VTableBuilder.cpp index bae018652f..e43acc4de7 100644 --- a/lib/AST/VTableBuilder.cpp +++ b/lib/AST/VTableBuilder.cpp @@ -2416,7 +2416,7 @@ private: MethodVFTableLocationsTy MethodVFTableLocations; /// \brief Does this class have an RTTI component? - bool HasRTTIComponent; + bool HasRTTIComponent = false; /// MethodInfo - Contains information about a method in a vtable. /// (Used for computing 'this' pointer adjustment thunks. @@ -2546,11 +2546,13 @@ public: WhichVFPtr(*Which), Overriders(MostDerivedClass, CharUnits(), MostDerivedClass) { // Only include the RTTI component if we know that we will provide a - // definition of the vftable. - HasRTTIComponent = Context.getLangOpts().RTTIData && - !MostDerivedClass->hasAttr() && - MostDerivedClass->getTemplateSpecializationKind() != - TSK_ExplicitInstantiationDeclaration; + // definition of the vftable. We always provide the definition of + // dllimported classes. + if (Context.getLangOpts().RTTIData) + if (MostDerivedClass->hasAttr() || + MostDerivedClass->getTemplateSpecializationKind() != + TSK_ExplicitInstantiationDeclaration) + HasRTTIComponent = true; LayoutVFTable(); diff --git a/lib/CodeGen/CGVTables.cpp b/lib/CodeGen/CGVTables.cpp index 620e9223b2..e96a812020 100644 --- a/lib/CodeGen/CGVTables.cpp +++ b/lib/CodeGen/CGVTables.cpp @@ -838,6 +838,11 @@ CodeGenVTables::GenerateClassData(const CXXRecordDecl *RD) { bool CodeGenVTables::isVTableExternal(const CXXRecordDecl *RD) { assert(RD->isDynamicClass() && "Non-dynamic classes have no VTable."); + // 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()) + return false; + // If we have an explicit instantiation declaration (and not a // definition), the vtable is defined elsewhere. TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind(); diff --git a/lib/CodeGen/MicrosoftCXXABI.cpp b/lib/CodeGen/MicrosoftCXXABI.cpp index 2870a91dd5..2567aa92f2 100644 --- a/lib/CodeGen/MicrosoftCXXABI.cpp +++ b/lib/CodeGen/MicrosoftCXXABI.cpp @@ -1673,7 +1673,16 @@ llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD, SmallString<256> VFTableName; mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName); - llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD); + // Classes marked __declspec(dllimport) need vftables generated on the + // import-side in order to support features like constexpr. No other + // translation unit relies on the emission of the local vftable, translation + // units are expected to generate them as needed. + // + // Because of this unique behavior, we maintain this logic here instead of + // getVTableLinkage. + llvm::GlobalValue::LinkageTypes VFTableLinkage = + RD->hasAttr() ? llvm::GlobalValue::LinkOnceODRLinkage + : CGM.getVTableLinkage(RD); bool VFTableComesFromAnotherTU = llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) || llvm::GlobalValue::isExternalLinkage(VFTableLinkage); @@ -1746,9 +1755,7 @@ llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD, if (C) VTable->setComdat(C); - if (RD->hasAttr()) - VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); - else if (RD->hasAttr()) + if (RD->hasAttr()) VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); VFTablesMap[ID] = VFTable; diff --git a/test/CodeGenCXX/PR26569.cpp b/test/CodeGenCXX/PR26569.cpp new file mode 100644 index 0000000000..666a6466aa --- /dev/null +++ b/test/CodeGenCXX/PR26569.cpp @@ -0,0 +1,17 @@ +// RUN: %clang_cc1 -triple i686-pc-win32 -fms-extensions -emit-llvm -O1 -disable-llvm-optzns %s -o - | FileCheck %s + +class A { + virtual void m_fn1(); +}; +template +class B : A {}; + +extern template class __declspec(dllimport) B; +class __declspec(dllexport) C : B {}; + +// CHECK: @[[VTABLE_C:.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast (%rtti.CompleteObjectLocator* @"\01??_R4C@@6B@" to i8*), i8* bitcast (void (%class.A*)* @"\01?m_fn1@A@@EAEXXZ" to i8*)] +// CHECK: @[[VTABLE_B:.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast (%rtti.CompleteObjectLocator* @"\01??_R4?$B@H@@6B@" to i8*), i8* bitcast (void (%class.A*)* @"\01?m_fn1@A@@EAEXXZ" to i8*)], comdat($"\01??_S?$B@H@@6B@") +// CHECK: @[[VTABLE_A:.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast (%rtti.CompleteObjectLocator* @"\01??_R4A@@6B@" to i8*), i8* bitcast (void (%class.A*)* @"\01?m_fn1@A@@EAEXXZ" to i8*)], comdat($"\01??_7A@@6B@") +// CHECK: @"\01??_7C@@6B@" = dllexport unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @[[VTABLE_C]], i32 0, i32 1) +// CHECK: @"\01??_S?$B@H@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @[[VTABLE_B]], i32 0, i32 1) +// CHECK: @"\01??_7A@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @[[VTABLE_A]], i32 0, i32 1) diff --git a/test/CodeGenCXX/dllimport-rtti.cpp b/test/CodeGenCXX/dllimport-rtti.cpp index 071ce278a5..4baee50fcf 100644 --- a/test/CodeGenCXX/dllimport-rtti.cpp +++ b/test/CodeGenCXX/dllimport-rtti.cpp @@ -4,7 +4,8 @@ struct __declspec(dllimport) S { virtual void f() {} } s; -// MSVC-DAG: @"\01??_7S@@6B@" = available_externally dllimport +// MSVC: [[VF_S:.*]] = private unnamed_addr constant [2 x i8*] +// MSVC-DAG: @"\01??_SS@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* [[VF_S]], i32 0, i32 1) // MSVC-DAG: @"\01??_R0?AUS@@@8" = linkonce_odr // MSVC-DAG: @"\01??_R1A@?0A@EA@S@@8" = linkonce_odr // MSVC-DAG: @"\01??_R2S@@8" = linkonce_odr diff --git a/test/CodeGenCXX/dllimport.cpp b/test/CodeGenCXX/dllimport.cpp index b9c850b8b8..e336bfb692 100644 --- a/test/CodeGenCXX/dllimport.cpp +++ b/test/CodeGenCXX/dllimport.cpp @@ -614,7 +614,7 @@ USEMEMFUNC(V, foo) struct __declspec(dllimport) W { virtual void foo() {} }; USECLASS(W) // vftable: -// MO1-DAG: @"\01??_7W@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast (void (%struct.W*)* @"\01?foo@W@@UAEXXZ" to i8*)] +// MO1-DAG: @"\01??_SW@@6B@" = linkonce_odr unnamed_addr constant [1 x i8*] [i8* bitcast (void (%struct.W*)* @"\01?foo@W@@UAEXXZ" to i8*)] // GO1-DAG: @_ZTV1W = available_externally dllimport unnamed_addr constant [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.W*)* @_ZN1W3fooEv to i8*)] struct __declspec(dllimport) KeyFuncClass { diff --git a/test/CodeGenCXX/microsoft-abi-vftables.cpp b/test/CodeGenCXX/microsoft-abi-vftables.cpp index f32bff09a8..d94c9c1a90 100644 --- a/test/CodeGenCXX/microsoft-abi-vftables.cpp +++ b/test/CodeGenCXX/microsoft-abi-vftables.cpp @@ -4,8 +4,6 @@ // RTTI-DAG: $"\01??_7S@@6B@" = comdat largest // RTTI-DAG: $"\01??_7V@@6B@" = comdat largest -// RTTI-NOT: @"\01??_R4U@@6B@" - struct S { virtual ~S(); } s; @@ -19,9 +17,10 @@ struct __declspec(dllimport) U { virtual ~U(); } u; -// RTTI-DAG: @"\01??_7U@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)] +// RTTI-DAG: [[VTABLE_U:@.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast ({{.*}} @"\01??_R4U@@6B@" to i8*), i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)] +// RTTI-DAG: @"\01??_SU@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* [[VTABLE_U]], i32 0, i32 1) -// NO-RTTI-DAG: @"\01??_7U@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)] +// NO-RTTI-DAG: @"\01??_SU@@6B@" = linkonce_odr unnamed_addr constant [1 x i8*] [i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)] struct __declspec(dllexport) V { virtual ~V();