From cc99e264756a8e29ed1e2521cf2f2d2db7095082 Mon Sep 17 00:00:00 2001 From: Reid Kleckner Date: Tue, 19 Nov 2013 23:23:00 +0000 Subject: [PATCH] Add a mangler entry point for TBAA rather than using RTTI directly Summary: RTTI is not yet implemented for the Microsoft C++ ABI and isn't expected soon. We could easily add the mangling, but the error is what prevents us from silently miscompiling code that expects RTTI. Instead, add a new mangleTypeName entry point that simply forwards to mangleName or mangleType to produce a string that isn't part of the ABI. Itanium can continue to use RTTI names to avoid unecessary test breakage. This also seems like the right design. The fact that TBAA names happen to be RTTI names is now an implementation detail of the mangler, rather than part of TBAA. Differential Revision: http://llvm-reviews.chandlerc.com/D2153 llvm-svn: 195168 --- clang/include/clang/AST/Mangle.h | 6 ++++++ clang/lib/AST/ItaniumMangle.cpp | 5 +++++ clang/lib/AST/MicrosoftMangle.cpp | 9 +++++++++ clang/lib/CodeGen/CodeGenTBAA.cpp | 10 +++------- clang/test/CodeGen/tbaa-ms-abi.cpp | 22 ++++++++++++++++++++++ 5 files changed, 45 insertions(+), 7 deletions(-) create mode 100644 clang/test/CodeGen/tbaa-ms-abi.cpp diff --git a/clang/include/clang/AST/Mangle.h b/clang/include/clang/AST/Mangle.h index e875c31fc002..4df2955aecc2 100644 --- a/clang/include/clang/AST/Mangle.h +++ b/clang/include/clang/AST/Mangle.h @@ -148,6 +148,12 @@ public: virtual void mangleDynamicAtExitDestructor(const VarDecl *D, raw_ostream &) = 0; + /// Generates a unique string for an externally visible type for use with TBAA + /// or type uniquing. + /// TODO: Extend this to internal types by generating names that are unique + /// across translation units so it can be used with LTO. + virtual void mangleTypeName(QualType T, raw_ostream &) = 0; + /// @} }; diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp index e94b4cf90732..0621d7b1ad86 100644 --- a/clang/lib/AST/ItaniumMangle.cpp +++ b/clang/lib/AST/ItaniumMangle.cpp @@ -144,6 +144,7 @@ public: raw_ostream &); void mangleCXXRTTI(QualType T, raw_ostream &); void mangleCXXRTTIName(QualType T, raw_ostream &); + void mangleTypeName(QualType T, raw_ostream &); void mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type, raw_ostream &); void mangleCXXDtor(const CXXDestructorDecl *D, CXXDtorType Type, @@ -3784,6 +3785,10 @@ void ItaniumMangleContextImpl::mangleCXXRTTIName(QualType Ty, Mangler.mangleType(Ty); } +void ItaniumMangleContextImpl::mangleTypeName(QualType Ty, raw_ostream &Out) { + mangleCXXRTTIName(Ty, Out); +} + ItaniumMangleContext * ItaniumMangleContext::create(ASTContext &Context, DiagnosticsEngine &Diags) { return new ItaniumMangleContextImpl(Context, Diags); diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp index ff1b0158c5d0..ed7168e3eb04 100644 --- a/clang/lib/AST/MicrosoftMangle.cpp +++ b/clang/lib/AST/MicrosoftMangle.cpp @@ -197,6 +197,7 @@ public: raw_ostream &Out); virtual void mangleCXXRTTI(QualType T, raw_ostream &); virtual void mangleCXXRTTIName(QualType T, raw_ostream &); + virtual void mangleTypeName(QualType T, raw_ostream &); virtual void mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type, raw_ostream &); virtual void mangleCXXDtor(const CXXDestructorDecl *D, CXXDtorType Type, @@ -2019,6 +2020,14 @@ void MicrosoftMangleContextImpl::mangleCXXRTTIName(QualType T, raw_ostream &) { << T.getBaseTypeIdentifier(); } +void MicrosoftMangleContextImpl::mangleTypeName(QualType T, raw_ostream &Out) { + // This is just a made up unique string for the purposes of tbaa. undname + // does *not* know how to demangle it. + MicrosoftCXXNameMangler Mangler(*this, Out); + Mangler.getStream() << '?'; + Mangler.mangleType(T, SourceRange()); +} + void MicrosoftMangleContextImpl::mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type, raw_ostream &Out) { diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp index 11e376ff4034..699cc2eabe18 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.cpp +++ b/clang/lib/CodeGen/CodeGenTBAA.cpp @@ -152,11 +152,9 @@ CodeGenTBAA::getTBAAInfo(QualType QTy) { if (!Features.CPlusPlus || !ETy->getDecl()->isExternallyVisible()) return MetadataCache[Ty] = getChar(); - // TODO: This is using the RTTI name. Is there a better way to get - // a unique string for a type? SmallString<256> OutName; llvm::raw_svector_ostream Out(OutName); - MContext.mangleCXXRTTIName(QualType(ETy, 0), Out); + MContext.mangleTypeName(QualType(ETy, 0), Out); Out.flush(); return MetadataCache[Ty] = createTBAAScalarType(OutName, getChar()); } @@ -268,13 +266,11 @@ CodeGenTBAA::getTBAAStructTypeInfo(QualType QTy) { FieldNode, Layout.getFieldOffset(idx) / Context.getCharWidth())); } - // TODO: This is using the RTTI name. Is there a better way to get - // a unique string for a type? SmallString<256> OutName; if (Features.CPlusPlus) { - // Don't use mangleCXXRTTIName for C code. + // Don't use the mangler for C code. llvm::raw_svector_ostream Out(OutName); - MContext.mangleCXXRTTIName(QualType(Ty, 0), Out); + MContext.mangleTypeName(QualType(Ty, 0), Out); Out.flush(); } else { OutName = RD->getName(); diff --git a/clang/test/CodeGen/tbaa-ms-abi.cpp b/clang/test/CodeGen/tbaa-ms-abi.cpp new file mode 100644 index 000000000000..67390b1a8a54 --- /dev/null +++ b/clang/test/CodeGen/tbaa-ms-abi.cpp @@ -0,0 +1,22 @@ +// RUN: %clang_cc1 -cxx-abi microsoft -triple i686-pc-win32 -disable-llvm-optzns -emit-llvm -o - -O1 %s | FileCheck %s +// +// Test that TBAA works in the Microsoft C++ ABI. We used to error out while +// attempting to mangle RTTI. + +struct StructA { + int a; +}; + +struct StructB : virtual StructA { + StructB(); +}; + +StructB::StructB() { + a = 42; +// CHECK: store i32 42, i32* {{.*}}, !tbaa [[TAG_A_i32:!.*]] +} + +// CHECK: [[TYPE_CHAR:!.*]] = metadata !{metadata !"omnipotent char", metadata +// CHECK: [[TYPE_INT:!.*]] = metadata !{metadata !"int", metadata [[TYPE_CHAR]], i64 0} +// CHECK: [[TAG_A_i32]] = metadata !{metadata [[TYPE_A:!.*]], metadata [[TYPE_INT]], i64 0} +// CHECK: [[TYPE_A]] = metadata !{metadata !"?AUStructA@@", metadata [[TYPE_INT]], i64 0}