diff options
Diffstat (limited to 'clang/lib/CodeGen/ItaniumCXXABI.cpp')
| -rw-r--r-- | clang/lib/CodeGen/ItaniumCXXABI.cpp | 1032 |
1 files changed, 1030 insertions, 2 deletions
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp index c33eb62ce2a..baf09274941 100644 --- a/clang/lib/CodeGen/ItaniumCXXABI.cpp +++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp @@ -109,6 +109,10 @@ public: llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF, llvm::Value *ptr, QualType type) override; + void EmitFundamentalRTTIDescriptor(QualType Type); + void EmitFundamentalRTTIDescriptors(); + llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override; + bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override; void EmitBadTypeidCall(CodeGenFunction &CGF) override; llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, @@ -238,6 +242,37 @@ public: QualType LValType) override; bool NeedsVTTParameter(GlobalDecl GD) override; + + /**************************** RTTI Uniqueness ******************************/ + +protected: + /// Returns true if the ABI requires RTTI type_info objects to be unique + /// across a program. + virtual bool shouldRTTIBeUnique() const { return true; } + +public: + /// What sort of unique-RTTI behavior should we use? + enum RTTIUniquenessKind { + /// We are guaranteeing, or need to guarantee, that the RTTI string + /// is unique. + RUK_Unique, + + /// We are not guaranteeing uniqueness for the RTTI string, so we + /// can demote to hidden visibility but must use string comparisons. + RUK_NonUniqueHidden, + + /// We are not guaranteeing uniqueness for the RTTI string, so we + /// have to use string comparisons, but we also have to emit it with + /// non-hidden visibility. + RUK_NonUniqueVisible + }; + + /// Return the required visibility status for the given type and linkage in + /// the current ABI. + RTTIUniquenessKind + classifyRTTIUniqueness(QualType CanTy, + llvm::GlobalValue::LinkageTypes Linkage) const; + friend class ItaniumRTTIBuilder; }; class ARMCXXABI : public ItaniumCXXABI { @@ -270,7 +305,7 @@ public: iOS64CXXABI(CodeGen::CodeGenModule &CGM) : ARMCXXABI(CGM) {} // ARM64 libraries are prepared for non-unique RTTI. - bool shouldRTTIBeUnique() override { return false; } + bool shouldRTTIBeUnique() const override { return false; } }; } @@ -1206,7 +1241,7 @@ void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT, isa<NamespaceDecl>(DC) && cast<NamespaceDecl>(DC)->getIdentifier() && cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__cxxabiv1") && DC->getParent()->isTranslationUnit()) - CGM.EmitFundamentalRTTIDescriptors(); + EmitFundamentalRTTIDescriptors(); } llvm::Value *ItaniumCXXABI::getVTableAddressPointInStructor( @@ -1944,3 +1979,996 @@ bool ItaniumCXXABI::NeedsVTTParameter(GlobalDecl GD) { return false; } + +namespace { +class ItaniumRTTIBuilder { + CodeGenModule &CGM; // Per-module state. + llvm::LLVMContext &VMContext; + const ItaniumCXXABI &CXXABI; // Per-module state. + + /// Fields - The fields of the RTTI descriptor currently being built. + SmallVector<llvm::Constant *, 16> Fields; + + /// GetAddrOfTypeName - Returns the mangled type name of the given type. + llvm::GlobalVariable * + GetAddrOfTypeName(QualType Ty, llvm::GlobalVariable::LinkageTypes Linkage); + + /// GetAddrOfExternalRTTIDescriptor - Returns the constant for the RTTI + /// descriptor of the given type. + llvm::Constant *GetAddrOfExternalRTTIDescriptor(QualType Ty); + + /// BuildVTablePointer - Build the vtable pointer for the given type. + void BuildVTablePointer(const Type *Ty); + + /// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single + /// inheritance, according to the Itanium C++ ABI, 2.9.5p6b. + void BuildSIClassTypeInfo(const CXXRecordDecl *RD); + + /// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for + /// classes with bases that do not satisfy the abi::__si_class_type_info + /// constraints, according ti the Itanium C++ ABI, 2.9.5p5c. + void BuildVMIClassTypeInfo(const CXXRecordDecl *RD); + + /// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct, used + /// for pointer types. + void BuildPointerTypeInfo(QualType PointeeTy); + + /// BuildObjCObjectTypeInfo - Build the appropriate kind of + /// type_info for an object type. + void BuildObjCObjectTypeInfo(const ObjCObjectType *Ty); + + /// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info + /// struct, used for member pointer types. + void BuildPointerToMemberTypeInfo(const MemberPointerType *Ty); + +public: + ItaniumRTTIBuilder(const ItaniumCXXABI &ABI) + : CGM(ABI.CGM), VMContext(CGM.getModule().getContext()), CXXABI(ABI) {} + + // Pointer type info flags. + enum { + /// PTI_Const - Type has const qualifier. + PTI_Const = 0x1, + + /// PTI_Volatile - Type has volatile qualifier. + PTI_Volatile = 0x2, + + /// PTI_Restrict - Type has restrict qualifier. + PTI_Restrict = 0x4, + + /// PTI_Incomplete - Type is incomplete. + PTI_Incomplete = 0x8, + + /// PTI_ContainingClassIncomplete - Containing class is incomplete. + /// (in pointer to member). + PTI_ContainingClassIncomplete = 0x10 + }; + + // VMI type info flags. + enum { + /// VMI_NonDiamondRepeat - Class has non-diamond repeated inheritance. + VMI_NonDiamondRepeat = 0x1, + + /// VMI_DiamondShaped - Class is diamond shaped. + VMI_DiamondShaped = 0x2 + }; + + // Base class type info flags. + enum { + /// BCTI_Virtual - Base class is virtual. + BCTI_Virtual = 0x1, + + /// BCTI_Public - Base class is public. + BCTI_Public = 0x2 + }; + + /// BuildTypeInfo - Build the RTTI type info struct for the given type. + /// + /// \param Force - true to force the creation of this RTTI value + llvm::Constant *BuildTypeInfo(QualType Ty, bool Force = false); +}; +} + +llvm::GlobalVariable *ItaniumRTTIBuilder::GetAddrOfTypeName( + QualType Ty, llvm::GlobalVariable::LinkageTypes Linkage) { + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + CGM.getCXXABI().getMangleContext().mangleCXXRTTIName(Ty, Out); + Out.flush(); + StringRef Name = OutName.str(); + + // We know that the mangled name of the type starts at index 4 of the + // mangled name of the typename, so we can just index into it in order to + // get the mangled name of the type. + llvm::Constant *Init = llvm::ConstantDataArray::getString(VMContext, + Name.substr(4)); + + llvm::GlobalVariable *GV = + CGM.CreateOrReplaceCXXRuntimeVariable(Name, Init->getType(), Linkage); + + GV->setInitializer(Init); + + return GV; +} + +llvm::Constant * +ItaniumRTTIBuilder::GetAddrOfExternalRTTIDescriptor(QualType Ty) { + // Mangle the RTTI name. + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty, Out); + Out.flush(); + StringRef Name = OutName.str(); + + // Look for an existing global. + llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name); + + if (!GV) { + // Create a new global variable. + GV = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy, + /*Constant=*/true, + llvm::GlobalValue::ExternalLinkage, nullptr, + Name); + } + + return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy); +} + +/// TypeInfoIsInStandardLibrary - Given a builtin type, returns whether the type +/// info for that type is defined in the standard library. +static bool TypeInfoIsInStandardLibrary(const BuiltinType *Ty) { + // Itanium C++ ABI 2.9.2: + // Basic type information (e.g. for "int", "bool", etc.) will be kept in + // the run-time support library. Specifically, the run-time support + // library should contain type_info objects for the types X, X* and + // X const*, for every X in: void, std::nullptr_t, bool, wchar_t, char, + // unsigned char, signed char, short, unsigned short, int, unsigned int, + // long, unsigned long, long long, unsigned long long, float, double, + // long double, char16_t, char32_t, and the IEEE 754r decimal and + // half-precision floating point types. + switch (Ty->getKind()) { + case BuiltinType::Void: + case BuiltinType::NullPtr: + case BuiltinType::Bool: + case BuiltinType::WChar_S: + case BuiltinType::WChar_U: + case BuiltinType::Char_U: + case BuiltinType::Char_S: + case BuiltinType::UChar: + case BuiltinType::SChar: + case BuiltinType::Short: + case BuiltinType::UShort: + case BuiltinType::Int: + case BuiltinType::UInt: + case BuiltinType::Long: + case BuiltinType::ULong: + case BuiltinType::LongLong: + case BuiltinType::ULongLong: + case BuiltinType::Half: + case BuiltinType::Float: + case BuiltinType::Double: + case BuiltinType::LongDouble: + case BuiltinType::Char16: + case BuiltinType::Char32: + case BuiltinType::Int128: + case BuiltinType::UInt128: + case BuiltinType::OCLImage1d: + case BuiltinType::OCLImage1dArray: + case BuiltinType::OCLImage1dBuffer: + case BuiltinType::OCLImage2d: + case BuiltinType::OCLImage2dArray: + case BuiltinType::OCLImage3d: + case BuiltinType::OCLSampler: + case BuiltinType::OCLEvent: + return true; + + case BuiltinType::Dependent: +#define BUILTIN_TYPE(Id, SingletonId) +#define PLACEHOLDER_TYPE(Id, SingletonId) \ + case BuiltinType::Id: +#include "clang/AST/BuiltinTypes.def" + llvm_unreachable("asking for RRTI for a placeholder type!"); + + case BuiltinType::ObjCId: + case BuiltinType::ObjCClass: + case BuiltinType::ObjCSel: + llvm_unreachable("FIXME: Objective-C types are unsupported!"); + } + + llvm_unreachable("Invalid BuiltinType Kind!"); +} + +static bool TypeInfoIsInStandardLibrary(const PointerType *PointerTy) { + QualType PointeeTy = PointerTy->getPointeeType(); + const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(PointeeTy); + if (!BuiltinTy) + return false; + + // Check the qualifiers. + Qualifiers Quals = PointeeTy.getQualifiers(); + Quals.removeConst(); + + if (!Quals.empty()) + return false; + + return TypeInfoIsInStandardLibrary(BuiltinTy); +} + +/// IsStandardLibraryRTTIDescriptor - Returns whether the type +/// information for the given type exists in the standard library. +static bool IsStandardLibraryRTTIDescriptor(QualType Ty) { + // Type info for builtin types is defined in the standard library. + if (const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(Ty)) + return TypeInfoIsInStandardLibrary(BuiltinTy); + + // Type info for some pointer types to builtin types is defined in the + // standard library. + if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty)) + return TypeInfoIsInStandardLibrary(PointerTy); + + return false; +} + +/// ShouldUseExternalRTTIDescriptor - Returns whether the type information for +/// the given type exists somewhere else, and that we should not emit the type +/// information in this translation unit. Assumes that it is not a +/// standard-library type. +static bool ShouldUseExternalRTTIDescriptor(CodeGenModule &CGM, + QualType Ty) { + ASTContext &Context = CGM.getContext(); + + // If RTTI is disabled, assume it might be disabled in the + // translation unit that defines any potential key function, too. + if (!Context.getLangOpts().RTTI) return false; + + if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) { + const CXXRecordDecl *RD = cast<CXXRecordDecl>(RecordTy->getDecl()); + if (!RD->hasDefinition()) + return false; + + if (!RD->isDynamicClass()) + return false; + + // FIXME: this may need to be reconsidered if the key function + // changes. + return CGM.getVTables().isVTableExternal(RD); + } + + return false; +} + +/// IsIncompleteClassType - Returns whether the given record type is incomplete. +static bool IsIncompleteClassType(const RecordType *RecordTy) { + return !RecordTy->getDecl()->isCompleteDefinition(); +} + +/// ContainsIncompleteClassType - Returns whether the given type contains an +/// incomplete class type. This is true if +/// +/// * The given type is an incomplete class type. +/// * The given type is a pointer type whose pointee type contains an +/// incomplete class type. +/// * The given type is a member pointer type whose class is an incomplete +/// class type. +/// * The given type is a member pointer type whoise pointee type contains an +/// incomplete class type. +/// is an indirect or direct pointer to an incomplete class type. +static bool ContainsIncompleteClassType(QualType Ty) { + if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) { + if (IsIncompleteClassType(RecordTy)) + return true; + } + + if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty)) + return ContainsIncompleteClassType(PointerTy->getPointeeType()); + + if (const MemberPointerType *MemberPointerTy = + dyn_cast<MemberPointerType>(Ty)) { + // Check if the class type is incomplete. + const RecordType *ClassType = cast<RecordType>(MemberPointerTy->getClass()); + if (IsIncompleteClassType(ClassType)) + return true; + + return ContainsIncompleteClassType(MemberPointerTy->getPointeeType()); + } + + return false; +} + +// CanUseSingleInheritance - Return whether the given record decl has a "single, +// public, non-virtual base at offset zero (i.e. the derived class is dynamic +// iff the base is)", according to Itanium C++ ABI, 2.95p6b. +static bool CanUseSingleInheritance(const CXXRecordDecl *RD) { + // Check the number of bases. + if (RD->getNumBases() != 1) + return false; + + // Get the base. + CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin(); + + // Check that the base is not virtual. + if (Base->isVirtual()) + return false; + + // Check that the base is public. + if (Base->getAccessSpecifier() != AS_public) + return false; + + // Check that the class is dynamic iff the base is. + const CXXRecordDecl *BaseDecl = + cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl()); + if (!BaseDecl->isEmpty() && + BaseDecl->isDynamicClass() != RD->isDynamicClass()) + return false; + + return true; +} + +void ItaniumRTTIBuilder::BuildVTablePointer(const Type *Ty) { + // abi::__class_type_info. + static const char * const ClassTypeInfo = + "_ZTVN10__cxxabiv117__class_type_infoE"; + // abi::__si_class_type_info. + static const char * const SIClassTypeInfo = + "_ZTVN10__cxxabiv120__si_class_type_infoE"; + // abi::__vmi_class_type_info. + static const char * const VMIClassTypeInfo = + "_ZTVN10__cxxabiv121__vmi_class_type_infoE"; + + const char *VTableName = nullptr; + + switch (Ty->getTypeClass()) { +#define TYPE(Class, Base) +#define ABSTRACT_TYPE(Class, Base) +#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class: +#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: +#define DEPENDENT_TYPE(Class, Base) case Type::Class: +#include "clang/AST/TypeNodes.def" + llvm_unreachable("Non-canonical and dependent types shouldn't get here"); + + case Type::LValueReference: + case Type::RValueReference: + llvm_unreachable("References shouldn't get here"); + + case Type::Auto: + llvm_unreachable("Undeduced auto type shouldn't get here"); + + case Type::Builtin: + // GCC treats vector and complex types as fundamental types. + case Type::Vector: + case Type::ExtVector: + case Type::Complex: + case Type::Atomic: + // FIXME: GCC treats block pointers as fundamental types?! + case Type::BlockPointer: + // abi::__fundamental_type_info. + VTableName = "_ZTVN10__cxxabiv123__fundamental_type_infoE"; + break; + + case Type::ConstantArray: + case Type::IncompleteArray: + case Type::VariableArray: + // abi::__array_type_info. + VTableName = "_ZTVN10__cxxabiv117__array_type_infoE"; + break; + + case Type::FunctionNoProto: + case Type::FunctionProto: + // abi::__function_type_info. + VTableName = "_ZTVN10__cxxabiv120__function_type_infoE"; + break; + + case Type::Enum: + // abi::__enum_type_info. + VTableName = "_ZTVN10__cxxabiv116__enum_type_infoE"; + break; + + case Type::Record: { + const CXXRecordDecl *RD = + cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl()); + + if (!RD->hasDefinition() || !RD->getNumBases()) { + VTableName = ClassTypeInfo; + } else if (CanUseSingleInheritance(RD)) { + VTableName = SIClassTypeInfo; + } else { + VTableName = VMIClassTypeInfo; + } + + break; + } + + case Type::ObjCObject: + // Ignore protocol qualifiers. + Ty = cast<ObjCObjectType>(Ty)->getBaseType().getTypePtr(); + + // Handle id and Class. + if (isa<BuiltinType>(Ty)) { + VTableName = ClassTypeInfo; + break; + } + + assert(isa<ObjCInterfaceType>(Ty)); + // Fall through. + + case Type::ObjCInterface: + if (cast<ObjCInterfaceType>(Ty)->getDecl()->getSuperClass()) { + VTableName = SIClassTypeInfo; + } else { + VTableName = ClassTypeInfo; + } + break; + + case Type::ObjCObjectPointer: + case Type::Pointer: + // abi::__pointer_type_info. + VTableName = "_ZTVN10__cxxabiv119__pointer_type_infoE"; + break; + + case Type::MemberPointer: + // abi::__pointer_to_member_type_info. + VTableName = "_ZTVN10__cxxabiv129__pointer_to_member_type_infoE"; + break; + } + + llvm::Constant *VTable = + CGM.getModule().getOrInsertGlobal(VTableName, CGM.Int8PtrTy); + + llvm::Type *PtrDiffTy = + CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType()); + + // The vtable address point is 2. + llvm::Constant *Two = llvm::ConstantInt::get(PtrDiffTy, 2); + VTable = llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, Two); + VTable = llvm::ConstantExpr::getBitCast(VTable, CGM.Int8PtrTy); + + Fields.push_back(VTable); +} + +/// \brief Return the linkage that the type info and type info name constants +/// should have for the given type. +static llvm::GlobalVariable::LinkageTypes getTypeInfoLinkage(CodeGenModule &CGM, + QualType Ty) { + // Itanium C++ ABI 2.9.5p7: + // In addition, it and all of the intermediate abi::__pointer_type_info + // structs in the chain down to the abi::__class_type_info for the + // incomplete class type must be prevented from resolving to the + // corresponding type_info structs for the complete class type, possibly + // by making them local static objects. Finally, a dummy class RTTI is + // generated for the incomplete type that will not resolve to the final + // complete class RTTI (because the latter need not exist), possibly by + // making it a local static object. + if (ContainsIncompleteClassType(Ty)) + return llvm::GlobalValue::InternalLinkage; + + switch (Ty->getLinkage()) { + case NoLinkage: + case InternalLinkage: + case UniqueExternalLinkage: + return llvm::GlobalValue::InternalLinkage; + + case VisibleNoLinkage: + case ExternalLinkage: + if (!CGM.getLangOpts().RTTI) { + // RTTI is not enabled, which means that this type info struct is going + // to be used for exception handling. Give it linkonce_odr linkage. + return llvm::GlobalValue::LinkOnceODRLinkage; + } + + if (const RecordType *Record = dyn_cast<RecordType>(Ty)) { + const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl()); + if (RD->hasAttr<WeakAttr>()) + return llvm::GlobalValue::WeakODRLinkage; + if (RD->isDynamicClass()) + return CGM.getVTableLinkage(RD); + } + + return llvm::GlobalValue::LinkOnceODRLinkage; + } + + llvm_unreachable("Invalid linkage!"); +} + +llvm::Constant *ItaniumRTTIBuilder::BuildTypeInfo(QualType Ty, bool Force) { + // We want to operate on the canonical type. + Ty = CGM.getContext().getCanonicalType(Ty); + + // Check if we've already emitted an RTTI descriptor for this type. + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty, Out); + Out.flush(); + StringRef Name = OutName.str(); + + llvm::GlobalVariable *OldGV = CGM.getModule().getNamedGlobal(Name); + if (OldGV && !OldGV->isDeclaration()) { + assert(!OldGV->hasAvailableExternallyLinkage() && + "available_externally typeinfos not yet implemented"); + + return llvm::ConstantExpr::getBitCast(OldGV, CGM.Int8PtrTy); + } + + // Check if there is already an external RTTI descriptor for this type. + bool IsStdLib = IsStandardLibraryRTTIDescriptor(Ty); + if (!Force && (IsStdLib || ShouldUseExternalRTTIDescriptor(CGM, Ty))) + return GetAddrOfExternalRTTIDescriptor(Ty); + + // Emit the standard library with external linkage. + llvm::GlobalVariable::LinkageTypes Linkage; + if (IsStdLib) + Linkage = llvm::GlobalValue::ExternalLinkage; + else + Linkage = getTypeInfoLinkage(CGM, Ty); + + // Add the vtable pointer. + BuildVTablePointer(cast<Type>(Ty)); + + // And the name. + llvm::GlobalVariable *TypeName = GetAddrOfTypeName(Ty, Linkage); + llvm::Constant *TypeNameField; + + // If we're supposed to demote the visibility, be sure to set a flag + // to use a string comparison for type_info comparisons. + ItaniumCXXABI::RTTIUniquenessKind RTTIUniqueness = + CXXABI.classifyRTTIUniqueness(Ty, Linkage); + if (RTTIUniqueness != ItaniumCXXABI::RUK_Unique) { + // The flag is the sign bit, which on ARM64 is defined to be clear + // for global pointers. This is very ARM64-specific. + TypeNameField = llvm::ConstantExpr::getPtrToInt(TypeName, CGM.Int64Ty); + llvm::Constant *flag = + llvm::ConstantInt::get(CGM.Int64Ty, ((uint64_t)1) << 63); + TypeNameField = llvm::ConstantExpr::getAdd(TypeNameField, flag); + TypeNameField = + llvm::ConstantExpr::getIntToPtr(TypeNameField, CGM.Int8PtrTy); + } else { + TypeNameField = llvm::ConstantExpr::getBitCast(TypeName, CGM.Int8PtrTy); + } + Fields.push_back(TypeNameField); + + switch (Ty->getTypeClass()) { +#define TYPE(Class, Base) +#define ABSTRACT_TYPE(Class, Base) +#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class: +#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: +#define DEPENDENT_TYPE(Class, Base) case Type::Class: +#include "clang/AST/TypeNodes.def" + llvm_unreachable("Non-canonical and dependent types shouldn't get here"); + + // GCC treats vector types as fundamental types. + case Type::Builtin: + case Type::Vector: + case Type::ExtVector: + case Type::Complex: + case Type::BlockPointer: + // Itanium C++ ABI 2.9.5p4: + // abi::__fundamental_type_info adds no data members to std::type_info. + break; + + case Type::LValueReference: + case Type::RValueReference: + llvm_unreachable("References shouldn't get here"); + + case Type::Auto: + llvm_unreachable("Undeduced auto type shouldn't get here"); + + case Type::ConstantArray: + case Type::IncompleteArray: + case Type::VariableArray: + // Itanium C++ ABI 2.9.5p5: + // abi::__array_type_info adds no data members to std::type_info. + break; + + case Type::FunctionNoProto: + case Type::FunctionProto: + // Itanium C++ ABI 2.9.5p5: + // abi::__function_type_info adds no data members to std::type_info. + break; + + case Type::Enum: + // Itanium C++ ABI 2.9.5p5: + // abi::__enum_type_info adds no data members to std::type_info. + break; + + case Type::Record: { + const CXXRecordDecl *RD = + cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl()); + if (!RD->hasDefinition() || !RD->getNumBases()) { + // We don't need to emit any fields. + break; + } + + if (CanUseSingleInheritance(RD)) + BuildSIClassTypeInfo(RD); + else + BuildVMIClassTypeInfo(RD); + + break; + } + + case Type::ObjCObject: + case Type::ObjCInterface: + BuildObjCObjectTypeInfo(cast<ObjCObjectType>(Ty)); + break; + + case Type::ObjCObjectPointer: + BuildPointerTypeInfo(cast<ObjCObjectPointerType>(Ty)->getPointeeType()); + break; + + case Type::Pointer: + BuildPointerTypeInfo(cast<PointerType>(Ty)->getPointeeType()); + break; + + case Type::MemberPointer: + BuildPointerToMemberTypeInfo(cast<MemberPointerType>(Ty)); + break; + + case Type::Atomic: + // No fields, at least for the moment. + break; + } + + llvm::Constant *Init = llvm::ConstantStruct::getAnon(Fields); + + llvm::GlobalVariable *GV = + new llvm::GlobalVariable(CGM.getModule(), Init->getType(), + /*Constant=*/true, Linkage, Init, Name); + + // If there's already an old global variable, replace it with the new one. + if (OldGV) { + GV->takeName(OldGV); + llvm::Constant *NewPtr = + llvm::ConstantExpr::getBitCast(GV, OldGV->getType()); + OldGV->replaceAllUsesWith(NewPtr); + OldGV->eraseFromParent(); + } + + // The Itanium ABI specifies that type_info objects must be globally + // unique, with one exception: if the type is an incomplete class + // type or a (possibly indirect) pointer to one. That exception + // affects the general case of comparing type_info objects produced + // by the typeid operator, which is why the comparison operators on + // std::type_info generally use the type_info name pointers instead + // of the object addresses. However, the language's built-in uses + // of RTTI generally require class types to be complete, even when + // manipulating pointers to those class types. This allows the + // implementation of dynamic_cast to rely on address equality tests, + // which is much faster. + + // All of this is to say that it's important that both the type_info + // object and the type_info name be uniqued when weakly emitted. + + // Give the type_info object and name the formal visibility of the + // type itself. + llvm::GlobalValue::VisibilityTypes llvmVisibility; + if (llvm::GlobalValue::isLocalLinkage(Linkage)) + // If the linkage is local, only default visibility makes sense. + llvmVisibility = llvm::GlobalValue::DefaultVisibility; + else if (RTTIUniqueness == ItaniumCXXABI::RUK_NonUniqueHidden) + llvmVisibility = llvm::GlobalValue::HiddenVisibility; + else + llvmVisibility = CodeGenModule::GetLLVMVisibility(Ty->getVisibility()); + TypeName->setVisibility(llvmVisibility); + GV->setVisibility(llvmVisibility); + + return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy); +} + +/// ComputeQualifierFlags - Compute the pointer type info flags from the +/// given qualifier. +static unsigned ComputeQualifierFlags(Qualifiers Quals) { + unsigned Flags = 0; + + if (Quals.hasConst()) + Flags |= ItaniumRTTIBuilder::PTI_Const; + if (Quals.hasVolatile()) + Flags |= ItaniumRTTIBuilder::PTI_Volatile; + if (Quals.hasRestrict()) + Flags |= ItaniumRTTIBuilder::PTI_Restrict; + + return Flags; +} + +/// BuildObjCObjectTypeInfo - Build the appropriate kind of type_info +/// for the given Objective-C object type. +void ItaniumRTTIBuilder::BuildObjCObjectTypeInfo(const ObjCObjectType *OT) { + // Drop qualifiers. + const Type *T = OT->getBaseType().getTypePtr(); + assert(isa<BuiltinType>(T) || isa<ObjCInterfaceType>(T)); + + // The builtin types are abi::__class_type_infos and don't require + // extra fields. + if (isa<BuiltinType>(T)) return; + + ObjCInterfaceDecl *Class = cast<ObjCInterfaceType>(T)->getDecl(); + ObjCInterfaceDecl *Super = Class->getSuperClass(); + + // Root classes are also __class_type_info. + if (!Super) return; + + QualType SuperTy = CGM.getContext().getObjCInterfaceType(Super); + + // Everything else is single inheritance. + llvm::Constant *BaseTypeInfo = + ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(SuperTy); + Fields.push_back(BaseTypeInfo); +} + +/// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single +/// inheritance, according to the Itanium C++ ABI, 2.95p6b. +void ItaniumRTTIBuilder::BuildSIClassTypeInfo(const CXXRecordDecl *RD) { + // Itanium C++ ABI 2.9.5p6b: + // It adds to abi::__class_type_info a single member pointing to the + // type_info structure for the base type, + llvm::Constant *BaseTypeInfo = + ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(RD->bases_begin()->getType()); + Fields.push_back(BaseTypeInfo); +} + +namespace { + /// SeenBases - Contains virtual and non-virtual bases seen when traversing + /// a class hierarchy. + struct SeenBases { + llvm::SmallPtrSet<const CXXRecordDecl *, 16> NonVirtualBases; + llvm::SmallPtrSet<const CXXRecordDecl *, 16> VirtualBases; + }; +} + +/// ComputeVMIClassTypeInfoFlags - Compute the value of the flags member in +/// abi::__vmi_class_type_info. +/// +static unsigned ComputeVMIClassTypeInfoFlags(const CXXBaseSpecifier *Base, + SeenBases &Bases) { + + unsigned Flags = 0; + + const CXXRecordDecl *BaseDecl = + cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl()); + + if (Base->isVirtual()) { + // Mark the virtual base as seen. + if (!Bases.VirtualBases.insert(BaseDecl)) { + // If this virtual base has been seen before, then the class is diamond + // shaped. + Flags |= ItaniumRTTIBuilder::VMI_DiamondShaped; + } else { + if (Bases.NonVirtualBases.count(BaseDecl)) + Flags |= ItaniumRTTIBuilder::VMI_NonDiamondRepeat; + } + } else { + // Mark the non-virtual base as seen. + if (!Bases.NonVirtualBases.insert(BaseDecl)) { + // If this non-virtual base has been seen before, then the class has non- + // diamond shaped repeated inheritance. + Flags |= ItaniumRTTIBuilder::VMI_NonDiamondRepeat; + } else { + if (Bases.VirtualBases.count(BaseDecl)) + Flags |= ItaniumRTTIBuilder::VMI_NonDiamondRepeat; + } + } + + // Walk all bases. + for (const auto &I : BaseDecl->bases()) + Flags |= ComputeVMIClassTypeInfoFlags(&I, Bases); + + return Flags; +} + +static unsigned ComputeVMIClassTypeInfoFlags(const CXXRecordDecl *RD) { + unsigned Flags = 0; + SeenBases Bases; + + // Walk all bases. + for (const auto &I : RD->bases()) + Flags |= ComputeVMIClassTypeInfoFlags(&I, Bases); + + return Flags; +} + +/// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for +/// classes with bases that do not satisfy the abi::__si_class_type_info +/// constraints, according ti the Itanium C++ ABI, 2.9.5p5c. +void ItaniumRTTIBuilder::BuildVMIClassTypeInfo(const CXXRecordDecl *RD) { + llvm::Type *UnsignedIntLTy = + CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy); + + // Itanium C++ ABI 2.9.5p6c: + // __flags is a word with flags describing details about the class + // structure, which may be referenced by using the __flags_masks + // enumeration. These flags refer to both direct and indirect bases. + unsigned Flags = ComputeVMIClassTypeInfoFlags(RD); + Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags)); + + // Itanium C++ ABI 2.9.5p6c: + // __base_count is a word with the number of direct proper base class + // descriptions that follow. + Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, RD->getNumBases())); + + if (!RD->getNumBases()) + return; + + llvm::Type *LongLTy = + CGM.getTypes().ConvertType(CGM.getContext().LongTy); + + // Now add the base class descriptions. + + // Itanium C++ ABI 2.9.5p6c: + // __base_info[] is an array of base class descriptions -- one for every + // direct proper base. Each description is of the type: + // + // struct abi::__base_class_type_info { + // public: + // const __class_type_info *__base_type; + // long __offset_flags; + // + // enum __offset_flags_masks { + // __virtual_mask = 0x1, + // __public_mask = 0x2, + // __offset_shift = 8 + // }; + // }; + for (const auto &Base : RD->bases()) { + // The __base_type member points to the RTTI for the base type. + Fields.push_back(ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(Base.getType())); + + const CXXRecordDecl *BaseDecl = + cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl()); + + int64_t OffsetFlags = 0; + + // All but the lower 8 bits of __offset_flags are a signed offset. + // For a non-virtual base, this is the offset in the object of the base + // subobject. For a virtual base, this is the offset in the virtual table of + // the virtual base offset for the virtual base referenced (negative). + CharUnits Offset; + if (Base.isVirtual()) + Offset = + CGM.getItaniumVTableContext().getVirtualBaseOffsetOffset(RD, BaseDecl); + else { + const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); + Offset = Layout.getBaseClassOffset(BaseDecl); + }; + + OffsetFlags = uint64_t(Offset.getQuantity()) << 8; + + // The low-order byte of __offset_flags contains flags, as given by the + // masks from the enumeration __offset_flags_masks. + if (Base.isVirtual()) + OffsetFlags |= BCTI_Virtual; + if (Base.getAccessSpecifier() == AS_public) + OffsetFlags |= BCTI_Public; + + Fields.push_back(llvm::ConstantInt::get(LongLTy, OffsetFlags)); + } +} + +/// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct, +/// used for pointer types. +void ItaniumRTTIBuilder::BuildPointerTypeInfo(QualType PointeeTy) { + Qualifiers Quals; + QualType UnqualifiedPointeeTy = + CGM.getContext().getUnqualifiedArrayType(PointeeTy, Quals); + + // Itanium C++ ABI 2.9.5p7: + // __flags is a flag word describing the cv-qualification and other + // attributes of the type pointed to + unsigned Flags = ComputeQualifierFlags(Quals); + + // Itanium C++ ABI 2.9.5p7: + // When the abi::__pbase_type_info is for a direct or indirect pointer to an + // incomplete class type, the incomplete target type flag is set. + if (ContainsIncompleteClassType(UnqualifiedPointeeTy)) + Flags |= PTI_Incomplete; + + llvm::Type *UnsignedIntLTy = + CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy); + Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags)); + + // Itanium C++ ABI 2.9.5p7: + // __pointee is a pointer to the std::type_info derivation for the + // unqualified type being pointed to. + llvm::Constant *PointeeTypeInfo = + ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(UnqualifiedPointeeTy); + Fields.push_back(PointeeTypeInfo); +} + +/// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info +/// struct, used for member pointer types. +void +ItaniumRTTIBuilder::BuildPointerToMemberTypeInfo(const MemberPointerType *Ty) { + QualType PointeeTy = Ty->getPointeeType(); + + Qualifiers Quals; + QualType UnqualifiedPointeeTy = + CGM.getContext().getUnqualifiedArrayType(PointeeTy, Quals); + + // Itanium C++ ABI 2.9.5p7: + // __flags is a flag word describing the cv-qualification and other + // attributes of the type pointed to. + unsigned Flags = ComputeQualifierFlags(Quals); + + const RecordType *ClassType = cast<RecordType>(Ty->getClass()); + + // Itanium C++ ABI 2.9.5p7: + // When the abi::__pbase_type_info is for a direct or indirect pointer to an + // incomplete class type, the incomplete target type flag is set. + if (ContainsIncompleteClassType(UnqualifiedPointeeTy)) + Flags |= PTI_Incomplete; + + if (IsIncompleteClassType(ClassType)) + Flags |= PTI_ContainingClassIncomplete; + + llvm::Type *UnsignedIntLTy = + CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy); + Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags)); + + // Itanium C++ ABI 2.9.5p7: + // __pointee is a pointer to the std::type_info derivation for the + // unqualified type being pointed to. + llvm::Constant *PointeeTypeInfo = + ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(UnqualifiedPointeeTy); + Fields.push_back(PointeeTypeInfo); + + // Itanium C++ ABI 2.9.5p9: + // __context is a pointer to an abi::__class_type_info corresponding to the + // class type containing the member pointed to + // (e.g., the "A" in "int A::*"). + Fields.push_back( + ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(QualType(ClassType, 0))); +} + +llvm::Constant *ItaniumCXXABI::getAddrOfRTTIDescriptor(QualType Ty) { + return ItaniumRTTIBuilder(*this).BuildTypeInfo(Ty); +} + +void ItaniumCXXABI::EmitFundamentalRTTIDescriptor(QualType Type) { + QualType PointerType = getContext().getPointerType(Type); + QualType PointerTypeConst = getContext().getPointerType(Type.withConst()); + ItaniumRTTIBuilder(*this).BuildTypeInfo(Type, true); + ItaniumRTTIBuilder(*this).BuildTypeInfo(PointerType, true); + ItaniumRTTIBuilder(*this).BuildTypeInfo(PointerTypeConst, true); +} + +void ItaniumCXXABI::EmitFundamentalRTTIDescriptors() { + QualType FundamentalTypes[] = { + getContext().VoidTy, getContext().NullPtrTy, + getContext().BoolTy, getContext().WCharTy, + getContext().CharTy, getContext().UnsignedCharTy, + getContext().SignedCharTy, getContext().ShortTy, + getContext().UnsignedShortTy, getContext().IntTy, + getContext().UnsignedIntTy, getContext().LongTy, + getContext().UnsignedLongTy, getContext().LongLongTy, + getContext().UnsignedLongLongTy, getContext().HalfTy, + getContext().FloatTy, getContext().DoubleTy, + getContext().LongDoubleTy, getContext().Char16Ty, + getContext().Char32Ty, + }; + for (const QualType &FundamentalType : FundamentalTypes) + EmitFundamentalRTTIDescriptor(FundamentalType); +} + +/// What sort of uniqueness rules should we use for the RTTI for the +/// given type? +ItaniumCXXABI::RTTIUniquenessKind ItaniumCXXABI::classifyRTTIUniqueness( + QualType CanTy, llvm::GlobalValue::LinkageTypes Linkage) const { + if (shouldRTTIBeUnique()) + return RUK_Unique; + + // It's only necessary for linkonce_odr or weak_odr linkage. + if (Linkage != llvm::GlobalValue::LinkOnceODRLinkage && + Linkage != llvm::GlobalValue::WeakODRLinkage) + return RUK_Unique; + + // It's only necessary with default visibility. + if (CanTy->getVisibility() != DefaultVisibility) + return RUK_Unique; + + // If we're not required to publish this symbol, hide it. + if (Linkage == llvm::GlobalValue::LinkOnceODRLinkage) + return RUK_NonUniqueHidden; + + // If we're required to publish this symbol, as we might be under an + // explicit instantiation, leave it with default visibility but + // enable string-comparisons. + assert(Linkage == llvm::GlobalValue::WeakODRLinkage); + return RUK_NonUniqueVisible; +} |
