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Diffstat (limited to 'clang/lib/CodeGen/CGRTTI.cpp')
| -rw-r--r-- | clang/lib/CodeGen/CGRTTI.cpp | 1015 |
1 files changed, 1015 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CGRTTI.cpp b/clang/lib/CodeGen/CGRTTI.cpp new file mode 100644 index 0000000..19973b4 --- /dev/null +++ b/clang/lib/CodeGen/CGRTTI.cpp @@ -0,0 +1,1015 @@ +//===--- CGCXXRTTI.cpp - Emit LLVM Code for C++ RTTI descriptors ----------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This contains code dealing with C++ code generation of RTTI descriptors. +// +//===----------------------------------------------------------------------===// + +#include "CodeGenModule.h" +#include "CGCXXABI.h" +#include "clang/AST/RecordLayout.h" +#include "clang/AST/Type.h" +#include "clang/Frontend/CodeGenOptions.h" +#include "CGObjCRuntime.h" + +using namespace clang; +using namespace CodeGen; + +namespace { +class RTTIBuilder { + CodeGenModule &CGM; // Per-module state. + llvm::LLVMContext &VMContext; + + /// 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: + RTTIBuilder(CodeGenModule &CGM) : CGM(CGM), + VMContext(CGM.getModule().getContext()) { } + + // 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 + /// \param ForEH - true if this is for exception handling + llvm::Constant *BuildTypeInfo(QualType Ty, bool Force = false); +}; +} + +llvm::GlobalVariable * +RTTIBuilder::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 *RTTIBuilder::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, 0, 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: + 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, don't consider key functions. + 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; + + return !CGM.getVTables().ShouldEmitVTableInThisTU(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; +} + +/// getTypeInfoLinkage - 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 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!"); +} + +// 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 RTTIBuilder::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 = 0; + + 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::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); +} + +// maybeUpdateRTTILinkage - Will update the linkage of the RTTI data structures +// from available_externally to the correct linkage if necessary. An example of +// this is: +// +// struct A { +// virtual void f(); +// }; +// +// const std::type_info &g() { +// return typeid(A); +// } +// +// void A::f() { } +// +// When we're generating the typeid(A) expression, we do not yet know that +// A's key function is defined in this translation unit, so we will give the +// typeinfo and typename structures available_externally linkage. When A::f +// forces the vtable to be generated, we need to change the linkage of the +// typeinfo and typename structs, otherwise we'll end up with undefined +// externals when linking. +static void +maybeUpdateRTTILinkage(CodeGenModule &CGM, llvm::GlobalVariable *GV, + QualType Ty) { + // We're only interested in globals with available_externally linkage. + if (!GV->hasAvailableExternallyLinkage()) + return; + + // Get the real linkage for the type. + llvm::GlobalVariable::LinkageTypes Linkage = getTypeInfoLinkage(CGM, Ty); + + // If variable is supposed to have available_externally linkage, we don't + // need to do anything. + if (Linkage == llvm::GlobalVariable::AvailableExternallyLinkage) + return; + + // Update the typeinfo linkage. + GV->setLinkage(Linkage); + + // Get the typename global. + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + CGM.getCXXABI().getMangleContext().mangleCXXRTTIName(Ty, Out); + Out.flush(); + StringRef Name = OutName.str(); + + llvm::GlobalVariable *TypeNameGV = CGM.getModule().getNamedGlobal(Name); + + assert(TypeNameGV->hasAvailableExternallyLinkage() && + "Type name has different linkage from type info!"); + + // And update its linkage. + TypeNameGV->setLinkage(Linkage); +} + +llvm::Constant *RTTIBuilder::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()) { + maybeUpdateRTTILinkage(CGM, OldGV, Ty); + + 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); + + Fields.push_back(llvm::ConstantExpr::getBitCast(TypeName, CGM.Int8PtrTy)); + + 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::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(); + } + + // GCC only relies on the uniqueness of the type names, not the + // type_infos themselves, so we can emit these as hidden symbols. + // But don't do this if we're worried about strict visibility + // compatibility. + if (const RecordType *RT = dyn_cast<RecordType>(Ty)) { + const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); + + CGM.setTypeVisibility(GV, RD, CodeGenModule::TVK_ForRTTI); + CGM.setTypeVisibility(TypeName, RD, CodeGenModule::TVK_ForRTTIName); + } else { + Visibility TypeInfoVisibility = DefaultVisibility; + if (CGM.getCodeGenOpts().HiddenWeakVTables && + Linkage == llvm::GlobalValue::LinkOnceODRLinkage) + TypeInfoVisibility = HiddenVisibility; + + // The type name should have the same visibility as the type itself. + Visibility ExplicitVisibility = Ty->getVisibility(); + TypeName->setVisibility(CodeGenModule:: + GetLLVMVisibility(ExplicitVisibility)); + + TypeInfoVisibility = minVisibility(TypeInfoVisibility, Ty->getVisibility()); + GV->setVisibility(CodeGenModule::GetLLVMVisibility(TypeInfoVisibility)); + } + + GV->setUnnamedAddr(true); + + 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 |= RTTIBuilder::PTI_Const; + if (Quals.hasVolatile()) + Flags |= RTTIBuilder::PTI_Volatile; + if (Quals.hasRestrict()) + Flags |= RTTIBuilder::PTI_Restrict; + + return Flags; +} + +/// BuildObjCObjectTypeInfo - Build the appropriate kind of type_info +/// for the given Objective-C object type. +void RTTIBuilder::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 = RTTIBuilder(CGM).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 RTTIBuilder::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 = + RTTIBuilder(CGM).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()) { + if (Bases.VirtualBases.count(BaseDecl)) { + // If this virtual base has been seen before, then the class is diamond + // shaped. + Flags |= RTTIBuilder::VMI_DiamondShaped; + } else { + if (Bases.NonVirtualBases.count(BaseDecl)) + Flags |= RTTIBuilder::VMI_NonDiamondRepeat; + + // Mark the virtual base as seen. + Bases.VirtualBases.insert(BaseDecl); + } + } else { + if (Bases.NonVirtualBases.count(BaseDecl)) { + // If this non-virtual base has been seen before, then the class has non- + // diamond shaped repeated inheritance. + Flags |= RTTIBuilder::VMI_NonDiamondRepeat; + } else { + if (Bases.VirtualBases.count(BaseDecl)) + Flags |= RTTIBuilder::VMI_NonDiamondRepeat; + + // Mark the non-virtual base as seen. + Bases.NonVirtualBases.insert(BaseDecl); + } + } + + // Walk all bases. + for (CXXRecordDecl::base_class_const_iterator I = BaseDecl->bases_begin(), + E = BaseDecl->bases_end(); I != E; ++I) + Flags |= ComputeVMIClassTypeInfoFlags(I, Bases); + + return Flags; +} + +static unsigned ComputeVMIClassTypeInfoFlags(const CXXRecordDecl *RD) { + unsigned Flags = 0; + SeenBases Bases; + + // Walk all bases. + for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), + E = RD->bases_end(); I != E; ++I) + 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 RTTIBuilder::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 (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), + E = RD->bases_end(); I != E; ++I) { + const CXXBaseSpecifier *Base = I; + + // The __base_type member points to the RTTI for the base type. + Fields.push_back(RTTIBuilder(CGM).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.getVTableContext().getVirtualBaseOffsetOffset(RD, BaseDecl); + else { + const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); + Offset = Layout.getBaseClassOffset(BaseDecl); + }; + + OffsetFlags = 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 RTTIBuilder::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 = + RTTIBuilder(CGM).BuildTypeInfo(UnqualifiedPointeeTy); + Fields.push_back(PointeeTypeInfo); +} + +/// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info +/// struct, used for member pointer types. +void RTTIBuilder::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 = + RTTIBuilder(CGM).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(RTTIBuilder(CGM).BuildTypeInfo(QualType(ClassType, 0))); +} + +llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty, + bool ForEH) { + // Return a bogus pointer if RTTI is disabled, unless it's for EH. + // FIXME: should we even be calling this method if RTTI is disabled + // and it's not for EH? + if (!ForEH && !getContext().getLangOpts().RTTI) + return llvm::Constant::getNullValue(Int8PtrTy); + + if (ForEH && Ty->isObjCObjectPointerType() && !LangOpts.NeXTRuntime) + return ObjCRuntime->GetEHType(Ty); + + return RTTIBuilder(*this).BuildTypeInfo(Ty); +} + +void CodeGenModule::EmitFundamentalRTTIDescriptor(QualType Type) { + QualType PointerType = Context.getPointerType(Type); + QualType PointerTypeConst = Context.getPointerType(Type.withConst()); + RTTIBuilder(*this).BuildTypeInfo(Type, true); + RTTIBuilder(*this).BuildTypeInfo(PointerType, true); + RTTIBuilder(*this).BuildTypeInfo(PointerTypeConst, true); +} + +void CodeGenModule::EmitFundamentalRTTIDescriptors() { + QualType FundamentalTypes[] = { Context.VoidTy, Context.NullPtrTy, + Context.BoolTy, Context.WCharTy, + Context.CharTy, Context.UnsignedCharTy, + Context.SignedCharTy, Context.ShortTy, + Context.UnsignedShortTy, Context.IntTy, + Context.UnsignedIntTy, Context.LongTy, + Context.UnsignedLongTy, Context.LongLongTy, + Context.UnsignedLongLongTy, Context.FloatTy, + Context.DoubleTy, Context.LongDoubleTy, + Context.Char16Ty, Context.Char32Ty }; + for (unsigned i = 0; i < sizeof(FundamentalTypes)/sizeof(QualType); ++i) + EmitFundamentalRTTIDescriptor(FundamentalTypes[i]); +} |