commit 24a925f05d57a720405b44a3d02307d71d6374d7 Author: Bob Wilson Date: Mon Jul 20 11:49:34 2015 -0700 Ignore the "novtable" declspec when not using the Microsoft C++ ABI. Clang used to silently ignore __declspec(novtable). It is implemented now, but leaving the vtable uninitialized does not work when using the Itanium ABI, where the class layout for complex class hierarchies is stored in the vtable. It might be possible to honor the novtable attribute in some simple cases and either report an error or ignore it in more complex situations, but it’s not clear if that would be worthwhile. There is also value in having a simple and predictable behavior, so this changes clang to simply ignore novtable when not using the Microsoft C++ ABI. diff --git include/clang/Basic/Attr.td include/clang/Basic/Attr.td index fb1eb58..e7143c7 100644 --- include/clang/Basic/Attr.td +++ include/clang/Basic/Attr.td @@ -241,14 +241,18 @@ def COnly : LangOpt<"CPlusPlus", 1>; class TargetArch arches> { list Arches = arches; list OSes; + list CXXABIs; } def TargetARM : TargetArch<["arm", "thumb"]>; +def TargetMips : TargetArch<["mips", "mipsel"]>; def TargetMSP430 : TargetArch<["msp430"]>; def TargetX86 : TargetArch<["x86"]>; def TargetWindows : TargetArch<["x86", "x86_64", "arm", "thumb"]> { let OSes = ["Win32"]; } -def TargetMips : TargetArch<["mips", "mipsel"]>; +def TargetMicrosoftCXXABI : TargetArch<["x86", "x86_64", "arm", "thumb"]> { + let CXXABIs = ["Microsoft"]; +} class Attr { // The various ways in which an attribute can be spelled in source @@ -1814,7 +1818,7 @@ def TypeTagForDatatype : InheritableAttr { // Microsoft-related attributes -def MSNoVTable : InheritableAttr { +def MSNoVTable : InheritableAttr, TargetSpecificAttr { let Spellings = [Declspec<"novtable">]; let Subjects = SubjectList<[CXXRecord]>; let Documentation = [MSNoVTableDocs]; diff --git include/clang/Basic/Attributes.h include/clang/Basic/Attributes.h index a64dd56..a2b8684 100644 --- include/clang/Basic/Attributes.h +++ include/clang/Basic/Attributes.h @@ -11,7 +11,7 @@ #define LLVM_CLANG_BASIC_ATTRIBUTES_H #include "clang/Basic/LangOptions.h" -#include "llvm/ADT/Triple.h" +#include "clang/Basic/TargetInfo.h" namespace clang { @@ -31,7 +31,7 @@ enum class AttrSyntax { /// \brief Return the version number associated with the attribute if we /// recognize and implement the attribute specified by the given information. int hasAttribute(AttrSyntax Syntax, const IdentifierInfo *Scope, - const IdentifierInfo *Attr, const llvm::Triple &T, + const IdentifierInfo *Attr, const TargetInfo &Target, const LangOptions &LangOpts); } // end namespace clang diff --git include/clang/Sema/AttributeList.h include/clang/Sema/AttributeList.h index 2fedc79..ca456b2 100644 --- include/clang/Sema/AttributeList.h +++ include/clang/Sema/AttributeList.h @@ -16,11 +16,11 @@ #define LLVM_CLANG_SEMA_ATTRIBUTELIST_H #include "clang/Basic/SourceLocation.h" +#include "clang/Basic/TargetInfo.h" #include "clang/Basic/VersionTuple.h" #include "clang/Sema/Ownership.h" #include "llvm/ADT/PointerUnion.h" #include "llvm/ADT/SmallVector.h" -#include "llvm/ADT/Triple.h" #include "llvm/Support/Allocator.h" #include @@ -464,7 +464,7 @@ public: bool hasVariadicArg() const; bool diagnoseAppertainsTo(class Sema &S, const Decl *D) const; bool diagnoseLangOpts(class Sema &S) const; - bool existsInTarget(const llvm::Triple &T) const; + bool existsInTarget(const TargetInfo &Target) const; bool isKnownToGCC() const; /// \brief If the parsed attribute has a semantic equivalent, and it would diff --git lib/Basic/Attributes.cpp lib/Basic/Attributes.cpp index da9ac79..c215366 100644 --- lib/Basic/Attributes.cpp +++ lib/Basic/Attributes.cpp @@ -4,8 +4,8 @@ using namespace clang; int clang::hasAttribute(AttrSyntax Syntax, const IdentifierInfo *Scope, - const IdentifierInfo *Attr, const llvm::Triple &T, - const LangOptions &LangOpts) { + const IdentifierInfo *Attr, const TargetInfo &Target, + const LangOptions &LangOpts) { StringRef Name = Attr->getName(); // Normalize the attribute name, __foo__ becomes foo. if (Name.size() >= 4 && Name.startswith("__") && Name.endswith("__")) diff --git lib/Lex/PPMacroExpansion.cpp lib/Lex/PPMacroExpansion.cpp index 1324ca9..42b1d04 100644 --- lib/Lex/PPMacroExpansion.cpp +++ lib/Lex/PPMacroExpansion.cpp @@ -1633,13 +1633,13 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) { Value = FeatureII->getBuiltinID() != 0; } else if (II == Ident__has_attribute) Value = hasAttribute(AttrSyntax::GNU, nullptr, FeatureII, - getTargetInfo().getTriple(), getLangOpts()); + getTargetInfo(), getLangOpts()); else if (II == Ident__has_cpp_attribute) Value = hasAttribute(AttrSyntax::CXX, ScopeII, FeatureII, - getTargetInfo().getTriple(), getLangOpts()); + getTargetInfo(), getLangOpts()); else if (II == Ident__has_declspec) Value = hasAttribute(AttrSyntax::Declspec, nullptr, FeatureII, - getTargetInfo().getTriple(), getLangOpts()); + getTargetInfo(), getLangOpts()); else if (II == Ident__has_extension) Value = HasExtension(*this, FeatureII); else { diff --git lib/Parse/ParseDecl.cpp lib/Parse/ParseDecl.cpp index f46af88..acfe0ca 100644 --- lib/Parse/ParseDecl.cpp +++ lib/Parse/ParseDecl.cpp @@ -387,7 +387,7 @@ bool Parser::ParseMicrosoftDeclSpecArgs(IdentifierInfo *AttrName, // If the attribute isn't known, we will not attempt to parse any // arguments. if (!hasAttribute(AttrSyntax::Declspec, nullptr, AttrName, - getTargetInfo().getTriple(), getLangOpts())) { + getTargetInfo(), getLangOpts())) { // Eat the left paren, then skip to the ending right paren. ConsumeParen(); SkipUntil(tok::r_paren); diff --git lib/Parse/ParseDeclCXX.cpp lib/Parse/ParseDeclCXX.cpp index e347d4e..0fb1de9 100644 --- lib/Parse/ParseDeclCXX.cpp +++ lib/Parse/ParseDeclCXX.cpp @@ -3612,7 +3612,7 @@ bool Parser::ParseCXX11AttributeArgs(IdentifierInfo *AttrName, // If the attribute isn't known, we will not attempt to parse any // arguments. if (!hasAttribute(AttrSyntax::CXX, ScopeName, AttrName, - getTargetInfo().getTriple(), getLangOpts())) { + getTargetInfo(), getLangOpts())) { // Eat the left paren, then skip to the ending right paren. ConsumeParen(); SkipUntil(tok::r_paren); diff --git lib/Sema/AttributeList.cpp lib/Sema/AttributeList.cpp index 34af6cf..1ea4060 100644 --- lib/Sema/AttributeList.cpp +++ lib/Sema/AttributeList.cpp @@ -17,6 +17,7 @@ #include "clang/AST/DeclTemplate.h" #include "clang/AST/Expr.h" #include "clang/Basic/IdentifierTable.h" +#include "clang/Basic/TargetInfo.h" #include "clang/Sema/SemaInternal.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringSwitch.h" @@ -155,7 +156,7 @@ struct ParsedAttrInfo { bool (*DiagAppertainsToDecl)(Sema &S, const AttributeList &Attr, const Decl *); bool (*DiagLangOpts)(Sema &S, const AttributeList &Attr); - bool (*ExistsInTarget)(const llvm::Triple &T); + bool (*ExistsInTarget)(const TargetInfo &Target); unsigned (*SpellingIndexToSemanticSpelling)(const AttributeList &Attr); }; @@ -195,8 +196,8 @@ bool AttributeList::isTypeAttr() const { return getInfo(*this).IsType; } -bool AttributeList::existsInTarget(const llvm::Triple &T) const { - return getInfo(*this).ExistsInTarget(T); +bool AttributeList::existsInTarget(const TargetInfo &Target) const { + return getInfo(*this).ExistsInTarget(Target); } bool AttributeList::isKnownToGCC() const { diff --git lib/Sema/SemaDeclAttr.cpp lib/Sema/SemaDeclAttr.cpp index 191dbd0..b8bd5e0 100644 --- lib/Sema/SemaDeclAttr.cpp +++ lib/Sema/SemaDeclAttr.cpp @@ -4583,7 +4583,7 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, // which do not apply to the current target architecture are treated as // though they were unknown attributes. if (Attr.getKind() == AttributeList::UnknownAttribute || - !Attr.existsInTarget(S.Context.getTargetInfo().getTriple())) { + !Attr.existsInTarget(S.Context.getTargetInfo())) { S.Diag(Attr.getLoc(), Attr.isDeclspecAttribute() ? diag::warn_unhandled_ms_attribute_ignored : diag::warn_unknown_attribute_ignored) diff --git test/SemaCXX/ms-novtable.cpp test/SemaCXX/ms-novtable.cpp index 2d55c48..31975b3 100644 --- test/SemaCXX/ms-novtable.cpp +++ test/SemaCXX/ms-novtable.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 %s -fsyntax-only -verify -fms-extensions -Wno-microsoft -std=c++11 +// RUN: %clang_cc1 -triple i386-pc-win32 %s -fsyntax-only -verify -fms-extensions -Wno-microsoft -std=c++11 struct __declspec(novtable) S {}; enum __declspec(novtable) E {}; // expected-warning{{'novtable' attribute only applies to classes}} diff --git test/SemaCXX/ms-unsupported.cpp test/SemaCXX/ms-unsupported.cpp new file mode 100644 index 0000000..559d703 --- /dev/null +++ test/SemaCXX/ms-unsupported.cpp @@ -0,0 +1,5 @@ +// RUN: %clang_cc1 -triple x86_64-pc-windows-gnu %s -fsyntax-only -verify -fms-extensions -Wno-microsoft -std=c++11 + +// "novtable" is ignored except with the Microsoft C++ ABI. +// MinGW uses the Itanium C++ ABI so check that it is ignored there. +struct __declspec(novtable) S {}; // expected-warning{{__declspec attribute 'novtable' is not supported}} diff --git utils/TableGen/ClangAttrEmitter.cpp utils/TableGen/ClangAttrEmitter.cpp index 5dc33a0..e990d8a 100644 --- utils/TableGen/ClangAttrEmitter.cpp +++ utils/TableGen/ClangAttrEmitter.cpp @@ -1885,7 +1885,8 @@ static void GenerateHasAttrSpellingStringSwitch( } } - // It is assumed that there will be an llvm::Triple object named T within + // It is assumed that there will be an llvm::Triple object + // named "T" and a TargetInfo object named "Target" within // scope that can be used to determine whether the attribute exists in // a given target. std::string Test; @@ -1902,6 +1903,7 @@ static void GenerateHasAttrSpellingStringSwitch( } Test += ")"; + // If the attribute is specific to particular OSes, check those. std::vector OSes; if (!R->isValueUnset("OSes")) { Test += " && ("; @@ -1916,6 +1918,22 @@ static void GenerateHasAttrSpellingStringSwitch( Test += ")"; } + // If one or more CXX ABIs are specified, check those as well. + std::vector CXXABIs; + if (!R->isValueUnset("CXXABIs")) { + Test += " && ("; + std::vector CXXABIs = + R->getValueAsListOfStrings("CXXABIs"); + for (auto AI = CXXABIs.begin(), AE = CXXABIs.end(); AI != AE; ++AI) { + std::string Part = *AI; + + Test += "Target.getCXXABI().getKind() == TargetCXXABI::" + Part; + if (AI + 1 != AE) + Test += " || "; + } + Test += ")"; + } + // If this is the C++11 variety, also add in the LangOpts test. if (Variety == "CXX11") Test += " && LangOpts.CPlusPlus11"; @@ -1962,6 +1980,7 @@ void EmitClangAttrHasAttrImpl(RecordKeeper &Records, raw_ostream &OS) { } } + OS << "const llvm::Triple &T = Target.getTriple();\n"; OS << "switch (Syntax) {\n"; OS << "case AttrSyntax::GNU:\n"; OS << " return llvm::StringSwitch(Name)\n"; @@ -2464,7 +2483,7 @@ static std::string GenerateLangOptRequirements(const Record &R, } static void GenerateDefaultTargetRequirements(raw_ostream &OS) { - OS << "static bool defaultTargetRequirements(const llvm::Triple &) {\n"; + OS << "static bool defaultTargetRequirements(const TargetInfo &) {\n"; OS << " return true;\n"; OS << "}\n\n"; } @@ -2533,6 +2552,20 @@ static std::string GenerateTargetRequirements(const Record &Attr, Test += ")"; } + // Test for the C++ ABI, if specified. + if (!R->isValueUnset("CXXABIs")) { + Test += " && ("; + std::vector CXXABIs = R->getValueAsListOfStrings("CXXABIs"); + for (auto I = CXXABIs.begin(), E = CXXABIs.end(); I != E; ++I) { + std::string Part = *I; + Test += "Target.getCXXABI().getKind() == TargetCXXABI::" + Part; + if (I + 1 != E) + Test += " || "; + FnName += Part; + } + Test += ")"; + } + // If this code has already been generated, simply return the previous // instance of it. static std::set CustomTargetSet; @@ -2540,7 +2573,8 @@ static std::string GenerateTargetRequirements(const Record &Attr, if (I != CustomTargetSet.end()) return *I; - OS << "static bool " << FnName << "(const llvm::Triple &T) {\n"; + OS << "static bool " << FnName << "(const TargetInfo &Target) {\n"; + OS << " const llvm::Triple &T = Target.getTriple();\n"; OS << " llvm::Triple::ArchType Arch = T.getArch();\n"; if (UsesOS) OS << " llvm::Triple::OSType OS = T.getOS();\n";