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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp | 2990 |
1 files changed, 2990 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp b/contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp new file mode 100644 index 0000000..d7e61f0 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp @@ -0,0 +1,2990 @@ +//===------- ItaniumCXXABI.cpp - Emit LLVM Code from ASTs for a Module ----===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This provides C++ code generation targeting the Itanium C++ ABI. The class +// in this file generates structures that follow the Itanium C++ ABI, which is +// documented at: +// http://www.codesourcery.com/public/cxx-abi/abi.html +// http://www.codesourcery.com/public/cxx-abi/abi-eh.html +// +// It also supports the closely-related ARM ABI, documented at: +// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf +// +//===----------------------------------------------------------------------===// + +#include "CGCXXABI.h" +#include "CGRecordLayout.h" +#include "CGVTables.h" +#include "CodeGenFunction.h" +#include "CodeGenModule.h" +#include "clang/AST/Mangle.h" +#include "clang/AST/Type.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Intrinsics.h" +#include "llvm/IR/Value.h" + +using namespace clang; +using namespace CodeGen; + +namespace { +class ItaniumCXXABI : public CodeGen::CGCXXABI { + /// VTables - All the vtables which have been defined. + llvm::DenseMap<const CXXRecordDecl *, llvm::GlobalVariable *> VTables; + +protected: + bool UseARMMethodPtrABI; + bool UseARMGuardVarABI; + + ItaniumMangleContext &getMangleContext() { + return cast<ItaniumMangleContext>(CodeGen::CGCXXABI::getMangleContext()); + } + +public: + ItaniumCXXABI(CodeGen::CodeGenModule &CGM, + bool UseARMMethodPtrABI = false, + bool UseARMGuardVarABI = false) : + CGCXXABI(CGM), UseARMMethodPtrABI(UseARMMethodPtrABI), + UseARMGuardVarABI(UseARMGuardVarABI) { } + + bool classifyReturnType(CGFunctionInfo &FI) const override; + + RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override { + // Structures with either a non-trivial destructor or a non-trivial + // copy constructor are always indirect. + // FIXME: Use canCopyArgument() when it is fixed to handle lazily declared + // special members. + if (RD->hasNonTrivialDestructor() || RD->hasNonTrivialCopyConstructor()) + return RAA_Indirect; + return RAA_Default; + } + + bool isZeroInitializable(const MemberPointerType *MPT) override; + + llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override; + + llvm::Value * + EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, + const Expr *E, + llvm::Value *&This, + llvm::Value *MemFnPtr, + const MemberPointerType *MPT) override; + + llvm::Value * + EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, + llvm::Value *Base, + llvm::Value *MemPtr, + const MemberPointerType *MPT) override; + + llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src) override; + llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src) override; + + llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override; + + llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override; + llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) override; + llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override; + llvm::Constant *BuildMemberPointer(const CXXMethodDecl *MD, + CharUnits ThisAdjustment); + + llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality) override; + + llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *Addr, + const MemberPointerType *MPT) override; + + 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, + llvm::Value *ThisPtr, + llvm::Type *StdTypeInfoPtrTy) override; + + bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) override; + + llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy, QualType DestTy, + QualType DestRecordTy, + llvm::BasicBlock *CastEnd) override; + + llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy, + QualType DestTy) override; + + bool EmitBadCastCall(CodeGenFunction &CGF) override; + + llvm::Value * + GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) override; + + void BuildConstructorSignature(const CXXConstructorDecl *Ctor, + CXXCtorType T, CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) override; + + void EmitCXXConstructors(const CXXConstructorDecl *D) override; + + void BuildDestructorSignature(const CXXDestructorDecl *Dtor, + CXXDtorType T, CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) override; + + bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, + CXXDtorType DT) const override { + // Itanium does not emit any destructor variant as an inline thunk. + // Delegating may occur as an optimization, but all variants are either + // emitted with external linkage or as linkonce if they are inline and used. + return false; + } + + void EmitCXXDestructors(const CXXDestructorDecl *D) override; + + void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, + FunctionArgList &Params) override; + + void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override; + + unsigned addImplicitConstructorArgs(CodeGenFunction &CGF, + const CXXConstructorDecl *D, + CXXCtorType Type, bool ForVirtualBase, + bool Delegating, + CallArgList &Args) override; + + void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD, + CXXDtorType Type, bool ForVirtualBase, + bool Delegating, llvm::Value *This) override; + + void emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) override; + + llvm::Value *getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, + BaseSubobject Base, const CXXRecordDecl *NearestVBase, + bool &NeedsVirtualOffset) override; + + llvm::Constant * + getVTableAddressPointForConstExpr(BaseSubobject Base, + const CXXRecordDecl *VTableClass) override; + + llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset) override; + + llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD, + llvm::Value *This, + llvm::Type *Ty) override; + + void EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, SourceLocation CallLoc, + llvm::Value *This) override; + + void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override; + + void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, GlobalDecl GD, + bool ReturnAdjustment) override { + // Allow inlining of thunks by emitting them with available_externally + // linkage together with vtables when needed. + if (ForVTable) + Thunk->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage); + } + + llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This, + const ThisAdjustment &TA) override; + + llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, + const ReturnAdjustment &RA) override; + + StringRef GetPureVirtualCallName() override { return "__cxa_pure_virtual"; } + StringRef GetDeletedVirtualCallName() override + { return "__cxa_deleted_virtual"; } + + CharUnits getArrayCookieSizeImpl(QualType elementType) override; + llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType) override; + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, + llvm::Value *allocPtr, + CharUnits cookieSize) override; + + void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *DeclPtr, + bool PerformInit) override; + void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, + llvm::Constant *dtor, llvm::Constant *addr) override; + + llvm::Function *getOrCreateThreadLocalWrapper(const VarDecl *VD, + llvm::GlobalVariable *Var); + void EmitThreadLocalInitFuncs( + ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls, + llvm::Function *InitFunc) override; + LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD, + 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 { +public: + ARMCXXABI(CodeGen::CodeGenModule &CGM) : + ItaniumCXXABI(CGM, /* UseARMMethodPtrABI = */ true, + /* UseARMGuardVarABI = */ true) {} + + bool HasThisReturn(GlobalDecl GD) const override { + return (isa<CXXConstructorDecl>(GD.getDecl()) || ( + isa<CXXDestructorDecl>(GD.getDecl()) && + GD.getDtorType() != Dtor_Deleting)); + } + + void EmitReturnFromThunk(CodeGenFunction &CGF, RValue RV, + QualType ResTy) override; + + CharUnits getArrayCookieSizeImpl(QualType elementType) override; + llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType) override; + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, llvm::Value *allocPtr, + CharUnits cookieSize) override; +}; + +class iOS64CXXABI : public ARMCXXABI { +public: + iOS64CXXABI(CodeGen::CodeGenModule &CGM) : ARMCXXABI(CGM) {} + + // ARM64 libraries are prepared for non-unique RTTI. + bool shouldRTTIBeUnique() const override { return false; } +}; +} + +CodeGen::CGCXXABI *CodeGen::CreateItaniumCXXABI(CodeGenModule &CGM) { + switch (CGM.getTarget().getCXXABI().getKind()) { + // For IR-generation purposes, there's no significant difference + // between the ARM and iOS ABIs. + case TargetCXXABI::GenericARM: + case TargetCXXABI::iOS: + return new ARMCXXABI(CGM); + + case TargetCXXABI::iOS64: + return new iOS64CXXABI(CGM); + + // Note that AArch64 uses the generic ItaniumCXXABI class since it doesn't + // include the other 32-bit ARM oddities: constructor/destructor return values + // and array cookies. + case TargetCXXABI::GenericAArch64: + return new ItaniumCXXABI(CGM, /* UseARMMethodPtrABI = */ true, + /* UseARMGuardVarABI = */ true); + + case TargetCXXABI::GenericItanium: + if (CGM.getContext().getTargetInfo().getTriple().getArch() + == llvm::Triple::le32) { + // For PNaCl, use ARM-style method pointers so that PNaCl code + // does not assume anything about the alignment of function + // pointers. + return new ItaniumCXXABI(CGM, /* UseARMMethodPtrABI = */ true, + /* UseARMGuardVarABI = */ false); + } + return new ItaniumCXXABI(CGM); + + case TargetCXXABI::Microsoft: + llvm_unreachable("Microsoft ABI is not Itanium-based"); + } + llvm_unreachable("bad ABI kind"); +} + +llvm::Type * +ItaniumCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) { + if (MPT->isMemberDataPointer()) + return CGM.PtrDiffTy; + return llvm::StructType::get(CGM.PtrDiffTy, CGM.PtrDiffTy, NULL); +} + +/// In the Itanium and ARM ABIs, method pointers have the form: +/// struct { ptrdiff_t ptr; ptrdiff_t adj; } memptr; +/// +/// In the Itanium ABI: +/// - method pointers are virtual if (memptr.ptr & 1) is nonzero +/// - the this-adjustment is (memptr.adj) +/// - the virtual offset is (memptr.ptr - 1) +/// +/// In the ARM ABI: +/// - method pointers are virtual if (memptr.adj & 1) is nonzero +/// - the this-adjustment is (memptr.adj >> 1) +/// - the virtual offset is (memptr.ptr) +/// ARM uses 'adj' for the virtual flag because Thumb functions +/// may be only single-byte aligned. +/// +/// If the member is virtual, the adjusted 'this' pointer points +/// to a vtable pointer from which the virtual offset is applied. +/// +/// If the member is non-virtual, memptr.ptr is the address of +/// the function to call. +llvm::Value *ItaniumCXXABI::EmitLoadOfMemberFunctionPointer( + CodeGenFunction &CGF, const Expr *E, llvm::Value *&This, + llvm::Value *MemFnPtr, const MemberPointerType *MPT) { + CGBuilderTy &Builder = CGF.Builder; + + const FunctionProtoType *FPT = + MPT->getPointeeType()->getAs<FunctionProtoType>(); + const CXXRecordDecl *RD = + cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); + + llvm::FunctionType *FTy = + CGM.getTypes().GetFunctionType( + CGM.getTypes().arrangeCXXMethodType(RD, FPT)); + + llvm::Constant *ptrdiff_1 = llvm::ConstantInt::get(CGM.PtrDiffTy, 1); + + llvm::BasicBlock *FnVirtual = CGF.createBasicBlock("memptr.virtual"); + llvm::BasicBlock *FnNonVirtual = CGF.createBasicBlock("memptr.nonvirtual"); + llvm::BasicBlock *FnEnd = CGF.createBasicBlock("memptr.end"); + + // Extract memptr.adj, which is in the second field. + llvm::Value *RawAdj = Builder.CreateExtractValue(MemFnPtr, 1, "memptr.adj"); + + // Compute the true adjustment. + llvm::Value *Adj = RawAdj; + if (UseARMMethodPtrABI) + Adj = Builder.CreateAShr(Adj, ptrdiff_1, "memptr.adj.shifted"); + + // Apply the adjustment and cast back to the original struct type + // for consistency. + llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy()); + Ptr = Builder.CreateInBoundsGEP(Ptr, Adj); + This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted"); + + // Load the function pointer. + llvm::Value *FnAsInt = Builder.CreateExtractValue(MemFnPtr, 0, "memptr.ptr"); + + // If the LSB in the function pointer is 1, the function pointer points to + // a virtual function. + llvm::Value *IsVirtual; + if (UseARMMethodPtrABI) + IsVirtual = Builder.CreateAnd(RawAdj, ptrdiff_1); + else + IsVirtual = Builder.CreateAnd(FnAsInt, ptrdiff_1); + IsVirtual = Builder.CreateIsNotNull(IsVirtual, "memptr.isvirtual"); + Builder.CreateCondBr(IsVirtual, FnVirtual, FnNonVirtual); + + // In the virtual path, the adjustment left 'This' pointing to the + // vtable of the correct base subobject. The "function pointer" is an + // offset within the vtable (+1 for the virtual flag on non-ARM). + CGF.EmitBlock(FnVirtual); + + // Cast the adjusted this to a pointer to vtable pointer and load. + llvm::Type *VTableTy = Builder.getInt8PtrTy(); + llvm::Value *VTable = CGF.GetVTablePtr(This, VTableTy); + + // Apply the offset. + llvm::Value *VTableOffset = FnAsInt; + if (!UseARMMethodPtrABI) + VTableOffset = Builder.CreateSub(VTableOffset, ptrdiff_1); + VTable = Builder.CreateGEP(VTable, VTableOffset); + + // Load the virtual function to call. + VTable = Builder.CreateBitCast(VTable, FTy->getPointerTo()->getPointerTo()); + llvm::Value *VirtualFn = Builder.CreateLoad(VTable, "memptr.virtualfn"); + CGF.EmitBranch(FnEnd); + + // In the non-virtual path, the function pointer is actually a + // function pointer. + CGF.EmitBlock(FnNonVirtual); + llvm::Value *NonVirtualFn = + Builder.CreateIntToPtr(FnAsInt, FTy->getPointerTo(), "memptr.nonvirtualfn"); + + // We're done. + CGF.EmitBlock(FnEnd); + llvm::PHINode *Callee = Builder.CreatePHI(FTy->getPointerTo(), 2); + Callee->addIncoming(VirtualFn, FnVirtual); + Callee->addIncoming(NonVirtualFn, FnNonVirtual); + return Callee; +} + +/// Compute an l-value by applying the given pointer-to-member to a +/// base object. +llvm::Value *ItaniumCXXABI::EmitMemberDataPointerAddress( + CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr, + const MemberPointerType *MPT) { + assert(MemPtr->getType() == CGM.PtrDiffTy); + + CGBuilderTy &Builder = CGF.Builder; + + unsigned AS = Base->getType()->getPointerAddressSpace(); + + // Cast to char*. + Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS)); + + // Apply the offset, which we assume is non-null. + llvm::Value *Addr = Builder.CreateInBoundsGEP(Base, MemPtr, "memptr.offset"); + + // Cast the address to the appropriate pointer type, adopting the + // address space of the base pointer. + llvm::Type *PType + = CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS); + return Builder.CreateBitCast(Addr, PType); +} + +/// Perform a bitcast, derived-to-base, or base-to-derived member pointer +/// conversion. +/// +/// Bitcast conversions are always a no-op under Itanium. +/// +/// Obligatory offset/adjustment diagram: +/// <-- offset --> <-- adjustment --> +/// |--------------------------|----------------------|--------------------| +/// ^Derived address point ^Base address point ^Member address point +/// +/// So when converting a base member pointer to a derived member pointer, +/// we add the offset to the adjustment because the address point has +/// decreased; and conversely, when converting a derived MP to a base MP +/// we subtract the offset from the adjustment because the address point +/// has increased. +/// +/// The standard forbids (at compile time) conversion to and from +/// virtual bases, which is why we don't have to consider them here. +/// +/// The standard forbids (at run time) casting a derived MP to a base +/// MP when the derived MP does not point to a member of the base. +/// This is why -1 is a reasonable choice for null data member +/// pointers. +llvm::Value * +ItaniumCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *src) { + assert(E->getCastKind() == CK_DerivedToBaseMemberPointer || + E->getCastKind() == CK_BaseToDerivedMemberPointer || + E->getCastKind() == CK_ReinterpretMemberPointer); + + // Under Itanium, reinterprets don't require any additional processing. + if (E->getCastKind() == CK_ReinterpretMemberPointer) return src; + + // Use constant emission if we can. + if (isa<llvm::Constant>(src)) + return EmitMemberPointerConversion(E, cast<llvm::Constant>(src)); + + llvm::Constant *adj = getMemberPointerAdjustment(E); + if (!adj) return src; + + CGBuilderTy &Builder = CGF.Builder; + bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer); + + const MemberPointerType *destTy = + E->getType()->castAs<MemberPointerType>(); + + // For member data pointers, this is just a matter of adding the + // offset if the source is non-null. + if (destTy->isMemberDataPointer()) { + llvm::Value *dst; + if (isDerivedToBase) + dst = Builder.CreateNSWSub(src, adj, "adj"); + else + dst = Builder.CreateNSWAdd(src, adj, "adj"); + + // Null check. + llvm::Value *null = llvm::Constant::getAllOnesValue(src->getType()); + llvm::Value *isNull = Builder.CreateICmpEQ(src, null, "memptr.isnull"); + return Builder.CreateSelect(isNull, src, dst); + } + + // The this-adjustment is left-shifted by 1 on ARM. + if (UseARMMethodPtrABI) { + uint64_t offset = cast<llvm::ConstantInt>(adj)->getZExtValue(); + offset <<= 1; + adj = llvm::ConstantInt::get(adj->getType(), offset); + } + + llvm::Value *srcAdj = Builder.CreateExtractValue(src, 1, "src.adj"); + llvm::Value *dstAdj; + if (isDerivedToBase) + dstAdj = Builder.CreateNSWSub(srcAdj, adj, "adj"); + else + dstAdj = Builder.CreateNSWAdd(srcAdj, adj, "adj"); + + return Builder.CreateInsertValue(src, dstAdj, 1); +} + +llvm::Constant * +ItaniumCXXABI::EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *src) { + assert(E->getCastKind() == CK_DerivedToBaseMemberPointer || + E->getCastKind() == CK_BaseToDerivedMemberPointer || + E->getCastKind() == CK_ReinterpretMemberPointer); + + // Under Itanium, reinterprets don't require any additional processing. + if (E->getCastKind() == CK_ReinterpretMemberPointer) return src; + + // If the adjustment is trivial, we don't need to do anything. + llvm::Constant *adj = getMemberPointerAdjustment(E); + if (!adj) return src; + + bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer); + + const MemberPointerType *destTy = + E->getType()->castAs<MemberPointerType>(); + + // For member data pointers, this is just a matter of adding the + // offset if the source is non-null. + if (destTy->isMemberDataPointer()) { + // null maps to null. + if (src->isAllOnesValue()) return src; + + if (isDerivedToBase) + return llvm::ConstantExpr::getNSWSub(src, adj); + else + return llvm::ConstantExpr::getNSWAdd(src, adj); + } + + // The this-adjustment is left-shifted by 1 on ARM. + if (UseARMMethodPtrABI) { + uint64_t offset = cast<llvm::ConstantInt>(adj)->getZExtValue(); + offset <<= 1; + adj = llvm::ConstantInt::get(adj->getType(), offset); + } + + llvm::Constant *srcAdj = llvm::ConstantExpr::getExtractValue(src, 1); + llvm::Constant *dstAdj; + if (isDerivedToBase) + dstAdj = llvm::ConstantExpr::getNSWSub(srcAdj, adj); + else + dstAdj = llvm::ConstantExpr::getNSWAdd(srcAdj, adj); + + return llvm::ConstantExpr::getInsertValue(src, dstAdj, 1); +} + +llvm::Constant * +ItaniumCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) { + // Itanium C++ ABI 2.3: + // A NULL pointer is represented as -1. + if (MPT->isMemberDataPointer()) + return llvm::ConstantInt::get(CGM.PtrDiffTy, -1ULL, /*isSigned=*/true); + + llvm::Constant *Zero = llvm::ConstantInt::get(CGM.PtrDiffTy, 0); + llvm::Constant *Values[2] = { Zero, Zero }; + return llvm::ConstantStruct::getAnon(Values); +} + +llvm::Constant * +ItaniumCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) { + // Itanium C++ ABI 2.3: + // A pointer to data member is an offset from the base address of + // the class object containing it, represented as a ptrdiff_t + return llvm::ConstantInt::get(CGM.PtrDiffTy, offset.getQuantity()); +} + +llvm::Constant *ItaniumCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) { + return BuildMemberPointer(MD, CharUnits::Zero()); +} + +llvm::Constant *ItaniumCXXABI::BuildMemberPointer(const CXXMethodDecl *MD, + CharUnits ThisAdjustment) { + assert(MD->isInstance() && "Member function must not be static!"); + MD = MD->getCanonicalDecl(); + + CodeGenTypes &Types = CGM.getTypes(); + + // Get the function pointer (or index if this is a virtual function). + llvm::Constant *MemPtr[2]; + if (MD->isVirtual()) { + uint64_t Index = CGM.getItaniumVTableContext().getMethodVTableIndex(MD); + + const ASTContext &Context = getContext(); + CharUnits PointerWidth = + Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0)); + uint64_t VTableOffset = (Index * PointerWidth.getQuantity()); + + if (UseARMMethodPtrABI) { + // ARM C++ ABI 3.2.1: + // This ABI specifies that adj contains twice the this + // adjustment, plus 1 if the member function is virtual. The + // least significant bit of adj then makes exactly the same + // discrimination as the least significant bit of ptr does for + // Itanium. + MemPtr[0] = llvm::ConstantInt::get(CGM.PtrDiffTy, VTableOffset); + MemPtr[1] = llvm::ConstantInt::get(CGM.PtrDiffTy, + 2 * ThisAdjustment.getQuantity() + 1); + } else { + // Itanium C++ ABI 2.3: + // For a virtual function, [the pointer field] is 1 plus the + // virtual table offset (in bytes) of the function, + // represented as a ptrdiff_t. + MemPtr[0] = llvm::ConstantInt::get(CGM.PtrDiffTy, VTableOffset + 1); + MemPtr[1] = llvm::ConstantInt::get(CGM.PtrDiffTy, + ThisAdjustment.getQuantity()); + } + } else { + const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); + llvm::Type *Ty; + // Check whether the function has a computable LLVM signature. + if (Types.isFuncTypeConvertible(FPT)) { + // The function has a computable LLVM signature; use the correct type. + Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD)); + } else { + // Use an arbitrary non-function type to tell GetAddrOfFunction that the + // function type is incomplete. + Ty = CGM.PtrDiffTy; + } + llvm::Constant *addr = CGM.GetAddrOfFunction(MD, Ty); + + MemPtr[0] = llvm::ConstantExpr::getPtrToInt(addr, CGM.PtrDiffTy); + MemPtr[1] = llvm::ConstantInt::get(CGM.PtrDiffTy, + (UseARMMethodPtrABI ? 2 : 1) * + ThisAdjustment.getQuantity()); + } + + return llvm::ConstantStruct::getAnon(MemPtr); +} + +llvm::Constant *ItaniumCXXABI::EmitMemberPointer(const APValue &MP, + QualType MPType) { + const MemberPointerType *MPT = MPType->castAs<MemberPointerType>(); + const ValueDecl *MPD = MP.getMemberPointerDecl(); + if (!MPD) + return EmitNullMemberPointer(MPT); + + CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP); + + if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) + return BuildMemberPointer(MD, ThisAdjustment); + + CharUnits FieldOffset = + getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD)); + return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset); +} + +/// The comparison algorithm is pretty easy: the member pointers are +/// the same if they're either bitwise identical *or* both null. +/// +/// ARM is different here only because null-ness is more complicated. +llvm::Value * +ItaniumCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, + llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality) { + CGBuilderTy &Builder = CGF.Builder; + + llvm::ICmpInst::Predicate Eq; + llvm::Instruction::BinaryOps And, Or; + if (Inequality) { + Eq = llvm::ICmpInst::ICMP_NE; + And = llvm::Instruction::Or; + Or = llvm::Instruction::And; + } else { + Eq = llvm::ICmpInst::ICMP_EQ; + And = llvm::Instruction::And; + Or = llvm::Instruction::Or; + } + + // Member data pointers are easy because there's a unique null + // value, so it just comes down to bitwise equality. + if (MPT->isMemberDataPointer()) + return Builder.CreateICmp(Eq, L, R); + + // For member function pointers, the tautologies are more complex. + // The Itanium tautology is: + // (L == R) <==> (L.ptr == R.ptr && (L.ptr == 0 || L.adj == R.adj)) + // The ARM tautology is: + // (L == R) <==> (L.ptr == R.ptr && + // (L.adj == R.adj || + // (L.ptr == 0 && ((L.adj|R.adj) & 1) == 0))) + // The inequality tautologies have exactly the same structure, except + // applying De Morgan's laws. + + llvm::Value *LPtr = Builder.CreateExtractValue(L, 0, "lhs.memptr.ptr"); + llvm::Value *RPtr = Builder.CreateExtractValue(R, 0, "rhs.memptr.ptr"); + + // This condition tests whether L.ptr == R.ptr. This must always be + // true for equality to hold. + llvm::Value *PtrEq = Builder.CreateICmp(Eq, LPtr, RPtr, "cmp.ptr"); + + // This condition, together with the assumption that L.ptr == R.ptr, + // tests whether the pointers are both null. ARM imposes an extra + // condition. + llvm::Value *Zero = llvm::Constant::getNullValue(LPtr->getType()); + llvm::Value *EqZero = Builder.CreateICmp(Eq, LPtr, Zero, "cmp.ptr.null"); + + // This condition tests whether L.adj == R.adj. If this isn't + // true, the pointers are unequal unless they're both null. + llvm::Value *LAdj = Builder.CreateExtractValue(L, 1, "lhs.memptr.adj"); + llvm::Value *RAdj = Builder.CreateExtractValue(R, 1, "rhs.memptr.adj"); + llvm::Value *AdjEq = Builder.CreateICmp(Eq, LAdj, RAdj, "cmp.adj"); + + // Null member function pointers on ARM clear the low bit of Adj, + // so the zero condition has to check that neither low bit is set. + if (UseARMMethodPtrABI) { + llvm::Value *One = llvm::ConstantInt::get(LPtr->getType(), 1); + + // Compute (l.adj | r.adj) & 1 and test it against zero. + llvm::Value *OrAdj = Builder.CreateOr(LAdj, RAdj, "or.adj"); + llvm::Value *OrAdjAnd1 = Builder.CreateAnd(OrAdj, One); + llvm::Value *OrAdjAnd1EqZero = Builder.CreateICmp(Eq, OrAdjAnd1, Zero, + "cmp.or.adj"); + EqZero = Builder.CreateBinOp(And, EqZero, OrAdjAnd1EqZero); + } + + // Tie together all our conditions. + llvm::Value *Result = Builder.CreateBinOp(Or, EqZero, AdjEq); + Result = Builder.CreateBinOp(And, PtrEq, Result, + Inequality ? "memptr.ne" : "memptr.eq"); + return Result; +} + +llvm::Value * +ItaniumCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *MemPtr, + const MemberPointerType *MPT) { + CGBuilderTy &Builder = CGF.Builder; + + /// For member data pointers, this is just a check against -1. + if (MPT->isMemberDataPointer()) { + assert(MemPtr->getType() == CGM.PtrDiffTy); + llvm::Value *NegativeOne = + llvm::Constant::getAllOnesValue(MemPtr->getType()); + return Builder.CreateICmpNE(MemPtr, NegativeOne, "memptr.tobool"); + } + + // In Itanium, a member function pointer is not null if 'ptr' is not null. + llvm::Value *Ptr = Builder.CreateExtractValue(MemPtr, 0, "memptr.ptr"); + + llvm::Constant *Zero = llvm::ConstantInt::get(Ptr->getType(), 0); + llvm::Value *Result = Builder.CreateICmpNE(Ptr, Zero, "memptr.tobool"); + + // On ARM, a member function pointer is also non-null if the low bit of 'adj' + // (the virtual bit) is set. + if (UseARMMethodPtrABI) { + llvm::Constant *One = llvm::ConstantInt::get(Ptr->getType(), 1); + llvm::Value *Adj = Builder.CreateExtractValue(MemPtr, 1, "memptr.adj"); + llvm::Value *VirtualBit = Builder.CreateAnd(Adj, One, "memptr.virtualbit"); + llvm::Value *IsVirtual = Builder.CreateICmpNE(VirtualBit, Zero, + "memptr.isvirtual"); + Result = Builder.CreateOr(Result, IsVirtual); + } + + return Result; +} + +bool ItaniumCXXABI::classifyReturnType(CGFunctionInfo &FI) const { + const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl(); + if (!RD) + return false; + + // Return indirectly if we have a non-trivial copy ctor or non-trivial dtor. + // FIXME: Use canCopyArgument() when it is fixed to handle lazily declared + // special members. + if (RD->hasNonTrivialDestructor() || RD->hasNonTrivialCopyConstructor()) { + FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false); + return true; + } + return false; +} + +/// The Itanium ABI requires non-zero initialization only for data +/// member pointers, for which '0' is a valid offset. +bool ItaniumCXXABI::isZeroInitializable(const MemberPointerType *MPT) { + return MPT->getPointeeType()->isFunctionType(); +} + +/// The Itanium ABI always places an offset to the complete object +/// at entry -2 in the vtable. +llvm::Value *ItaniumCXXABI::adjustToCompleteObject(CodeGenFunction &CGF, + llvm::Value *ptr, + QualType type) { + // Grab the vtable pointer as an intptr_t*. + llvm::Value *vtable = CGF.GetVTablePtr(ptr, CGF.IntPtrTy->getPointerTo()); + + // Track back to entry -2 and pull out the offset there. + llvm::Value *offsetPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(vtable, -2, "complete-offset.ptr"); + llvm::LoadInst *offset = CGF.Builder.CreateLoad(offsetPtr); + offset->setAlignment(CGF.PointerAlignInBytes); + + // Apply the offset. + ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy); + return CGF.Builder.CreateInBoundsGEP(ptr, offset); +} + +static llvm::Constant *getItaniumDynamicCastFn(CodeGenFunction &CGF) { + // void *__dynamic_cast(const void *sub, + // const abi::__class_type_info *src, + // const abi::__class_type_info *dst, + // std::ptrdiff_t src2dst_offset); + + llvm::Type *Int8PtrTy = CGF.Int8PtrTy; + llvm::Type *PtrDiffTy = + CGF.ConvertType(CGF.getContext().getPointerDiffType()); + + llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy }; + + llvm::FunctionType *FTy = llvm::FunctionType::get(Int8PtrTy, Args, false); + + // Mark the function as nounwind readonly. + llvm::Attribute::AttrKind FuncAttrs[] = { llvm::Attribute::NoUnwind, + llvm::Attribute::ReadOnly }; + llvm::AttributeSet Attrs = llvm::AttributeSet::get( + CGF.getLLVMContext(), llvm::AttributeSet::FunctionIndex, FuncAttrs); + + return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast", Attrs); +} + +static llvm::Constant *getBadCastFn(CodeGenFunction &CGF) { + // void __cxa_bad_cast(); + llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); + return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast"); +} + +/// \brief Compute the src2dst_offset hint as described in the +/// Itanium C++ ABI [2.9.7] +static CharUnits computeOffsetHint(ASTContext &Context, + const CXXRecordDecl *Src, + const CXXRecordDecl *Dst) { + CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, + /*DetectVirtual=*/false); + + // If Dst is not derived from Src we can skip the whole computation below and + // return that Src is not a public base of Dst. Record all inheritance paths. + if (!Dst->isDerivedFrom(Src, Paths)) + return CharUnits::fromQuantity(-2ULL); + + unsigned NumPublicPaths = 0; + CharUnits Offset; + + // Now walk all possible inheritance paths. + for (CXXBasePaths::paths_iterator I = Paths.begin(), E = Paths.end(); I != E; + ++I) { + if (I->Access != AS_public) // Ignore non-public inheritance. + continue; + + ++NumPublicPaths; + + for (CXXBasePath::iterator J = I->begin(), JE = I->end(); J != JE; ++J) { + // If the path contains a virtual base class we can't give any hint. + // -1: no hint. + if (J->Base->isVirtual()) + return CharUnits::fromQuantity(-1ULL); + + if (NumPublicPaths > 1) // Won't use offsets, skip computation. + continue; + + // Accumulate the base class offsets. + const ASTRecordLayout &L = Context.getASTRecordLayout(J->Class); + Offset += L.getBaseClassOffset(J->Base->getType()->getAsCXXRecordDecl()); + } + } + + // -2: Src is not a public base of Dst. + if (NumPublicPaths == 0) + return CharUnits::fromQuantity(-2ULL); + + // -3: Src is a multiple public base type but never a virtual base type. + if (NumPublicPaths > 1) + return CharUnits::fromQuantity(-3ULL); + + // Otherwise, the Src type is a unique public nonvirtual base type of Dst. + // Return the offset of Src from the origin of Dst. + return Offset; +} + +static llvm::Constant *getBadTypeidFn(CodeGenFunction &CGF) { + // void __cxa_bad_typeid(); + llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); + + return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid"); +} + +bool ItaniumCXXABI::shouldTypeidBeNullChecked(bool IsDeref, + QualType SrcRecordTy) { + return IsDeref; +} + +void ItaniumCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) { + llvm::Value *Fn = getBadTypeidFn(CGF); + CGF.EmitRuntimeCallOrInvoke(Fn).setDoesNotReturn(); + CGF.Builder.CreateUnreachable(); +} + +llvm::Value *ItaniumCXXABI::EmitTypeid(CodeGenFunction &CGF, + QualType SrcRecordTy, + llvm::Value *ThisPtr, + llvm::Type *StdTypeInfoPtrTy) { + llvm::Value *Value = + CGF.GetVTablePtr(ThisPtr, StdTypeInfoPtrTy->getPointerTo()); + + // Load the type info. + Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL); + return CGF.Builder.CreateLoad(Value); +} + +bool ItaniumCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) { + return SrcIsPtr; +} + +llvm::Value *ItaniumCXXABI::EmitDynamicCastCall( + CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy, + QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) { + llvm::Type *PtrDiffLTy = + CGF.ConvertType(CGF.getContext().getPointerDiffType()); + llvm::Type *DestLTy = CGF.ConvertType(DestTy); + + llvm::Value *SrcRTTI = + CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType()); + llvm::Value *DestRTTI = + CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType()); + + // Compute the offset hint. + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + const CXXRecordDecl *DestDecl = DestRecordTy->getAsCXXRecordDecl(); + llvm::Value *OffsetHint = llvm::ConstantInt::get( + PtrDiffLTy, + computeOffsetHint(CGF.getContext(), SrcDecl, DestDecl).getQuantity()); + + // Emit the call to __dynamic_cast. + Value = CGF.EmitCastToVoidPtr(Value); + + llvm::Value *args[] = {Value, SrcRTTI, DestRTTI, OffsetHint}; + Value = CGF.EmitNounwindRuntimeCall(getItaniumDynamicCastFn(CGF), args); + Value = CGF.Builder.CreateBitCast(Value, DestLTy); + + /// C++ [expr.dynamic.cast]p9: + /// A failed cast to reference type throws std::bad_cast + if (DestTy->isReferenceType()) { + llvm::BasicBlock *BadCastBlock = + CGF.createBasicBlock("dynamic_cast.bad_cast"); + + llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value); + CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd); + + CGF.EmitBlock(BadCastBlock); + EmitBadCastCall(CGF); + } + + return Value; +} + +llvm::Value *ItaniumCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, + llvm::Value *Value, + QualType SrcRecordTy, + QualType DestTy) { + llvm::Type *PtrDiffLTy = + CGF.ConvertType(CGF.getContext().getPointerDiffType()); + llvm::Type *DestLTy = CGF.ConvertType(DestTy); + + // Get the vtable pointer. + llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo()); + + // Get the offset-to-top from the vtable. + llvm::Value *OffsetToTop = + CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL); + OffsetToTop = CGF.Builder.CreateLoad(OffsetToTop, "offset.to.top"); + + // Finally, add the offset to the pointer. + Value = CGF.EmitCastToVoidPtr(Value); + Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop); + + return CGF.Builder.CreateBitCast(Value, DestLTy); +} + +bool ItaniumCXXABI::EmitBadCastCall(CodeGenFunction &CGF) { + llvm::Value *Fn = getBadCastFn(CGF); + CGF.EmitRuntimeCallOrInvoke(Fn).setDoesNotReturn(); + CGF.Builder.CreateUnreachable(); + return true; +} + +llvm::Value * +ItaniumCXXABI::GetVirtualBaseClassOffset(CodeGenFunction &CGF, + llvm::Value *This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) { + llvm::Value *VTablePtr = CGF.GetVTablePtr(This, CGM.Int8PtrTy); + CharUnits VBaseOffsetOffset = + CGM.getItaniumVTableContext().getVirtualBaseOffsetOffset(ClassDecl, + BaseClassDecl); + + llvm::Value *VBaseOffsetPtr = + CGF.Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset.getQuantity(), + "vbase.offset.ptr"); + VBaseOffsetPtr = CGF.Builder.CreateBitCast(VBaseOffsetPtr, + CGM.PtrDiffTy->getPointerTo()); + + llvm::Value *VBaseOffset = + CGF.Builder.CreateLoad(VBaseOffsetPtr, "vbase.offset"); + + return VBaseOffset; +} + +/// The generic ABI passes 'this', plus a VTT if it's initializing a +/// base subobject. +void +ItaniumCXXABI::BuildConstructorSignature(const CXXConstructorDecl *Ctor, + CXXCtorType Type, CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) { + ASTContext &Context = getContext(); + + // All parameters are already in place except VTT, which goes after 'this'. + // These are Clang types, so we don't need to worry about sret yet. + + // Check if we need to add a VTT parameter (which has type void **). + if (Type == Ctor_Base && Ctor->getParent()->getNumVBases() != 0) + ArgTys.insert(ArgTys.begin() + 1, + Context.getPointerType(Context.VoidPtrTy)); +} + +void ItaniumCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) { + // Just make sure we're in sync with TargetCXXABI. + assert(CGM.getTarget().getCXXABI().hasConstructorVariants()); + + // The constructor used for constructing this as a base class; + // ignores virtual bases. + CGM.EmitGlobal(GlobalDecl(D, Ctor_Base)); + + // The constructor used for constructing this as a complete class; + // constucts the virtual bases, then calls the base constructor. + if (!D->getParent()->isAbstract()) { + // We don't need to emit the complete ctor if the class is abstract. + CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete)); + } +} + +/// The generic ABI passes 'this', plus a VTT if it's destroying a +/// base subobject. +void ItaniumCXXABI::BuildDestructorSignature(const CXXDestructorDecl *Dtor, + CXXDtorType Type, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) { + ASTContext &Context = getContext(); + + // 'this' parameter is already there, as well as 'this' return if + // HasThisReturn(GlobalDecl(Dtor, Type)) is true + + // Check if we need to add a VTT parameter (which has type void **). + if (Type == Dtor_Base && Dtor->getParent()->getNumVBases() != 0) + ArgTys.push_back(Context.getPointerType(Context.VoidPtrTy)); +} + +void ItaniumCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) { + // The destructor used for destructing this as a base class; ignores + // virtual bases. + CGM.EmitGlobal(GlobalDecl(D, Dtor_Base)); + + // The destructor used for destructing this as a most-derived class; + // call the base destructor and then destructs any virtual bases. + CGM.EmitGlobal(GlobalDecl(D, Dtor_Complete)); + + // The destructor in a virtual table is always a 'deleting' + // destructor, which calls the complete destructor and then uses the + // appropriate operator delete. + if (D->isVirtual()) + CGM.EmitGlobal(GlobalDecl(D, Dtor_Deleting)); +} + +void ItaniumCXXABI::addImplicitStructorParams(CodeGenFunction &CGF, + QualType &ResTy, + FunctionArgList &Params) { + const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); + assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD)); + + // Check if we need a VTT parameter as well. + if (NeedsVTTParameter(CGF.CurGD)) { + ASTContext &Context = getContext(); + + // FIXME: avoid the fake decl + QualType T = Context.getPointerType(Context.VoidPtrTy); + ImplicitParamDecl *VTTDecl + = ImplicitParamDecl::Create(Context, nullptr, MD->getLocation(), + &Context.Idents.get("vtt"), T); + Params.insert(Params.begin() + 1, VTTDecl); + getStructorImplicitParamDecl(CGF) = VTTDecl; + } +} + +void ItaniumCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) { + /// Initialize the 'this' slot. + EmitThisParam(CGF); + + /// Initialize the 'vtt' slot if needed. + if (getStructorImplicitParamDecl(CGF)) { + getStructorImplicitParamValue(CGF) = CGF.Builder.CreateLoad( + CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)), "vtt"); + } + + /// If this is a function that the ABI specifies returns 'this', initialize + /// the return slot to 'this' at the start of the function. + /// + /// Unlike the setting of return types, this is done within the ABI + /// implementation instead of by clients of CGCXXABI because: + /// 1) getThisValue is currently protected + /// 2) in theory, an ABI could implement 'this' returns some other way; + /// HasThisReturn only specifies a contract, not the implementation + if (HasThisReturn(CGF.CurGD)) + CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue); +} + +unsigned ItaniumCXXABI::addImplicitConstructorArgs( + CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type, + bool ForVirtualBase, bool Delegating, CallArgList &Args) { + if (!NeedsVTTParameter(GlobalDecl(D, Type))) + return 0; + + // Insert the implicit 'vtt' argument as the second argument. + llvm::Value *VTT = + CGF.GetVTTParameter(GlobalDecl(D, Type), ForVirtualBase, Delegating); + QualType VTTTy = getContext().getPointerType(getContext().VoidPtrTy); + Args.insert(Args.begin() + 1, + CallArg(RValue::get(VTT), VTTTy, /*needscopy=*/false)); + return 1; // Added one arg. +} + +void ItaniumCXXABI::EmitDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *DD, + CXXDtorType Type, bool ForVirtualBase, + bool Delegating, llvm::Value *This) { + GlobalDecl GD(DD, Type); + llvm::Value *VTT = CGF.GetVTTParameter(GD, ForVirtualBase, Delegating); + QualType VTTTy = getContext().getPointerType(getContext().VoidPtrTy); + + llvm::Value *Callee = nullptr; + if (getContext().getLangOpts().AppleKext) + Callee = CGF.BuildAppleKextVirtualDestructorCall(DD, Type, DD->getParent()); + + if (!Callee) + Callee = CGM.GetAddrOfCXXDestructor(DD, Type); + + // FIXME: Provide a source location here. + CGF.EmitCXXMemberCall(DD, SourceLocation(), Callee, ReturnValueSlot(), This, + VTT, VTTTy, nullptr, nullptr); +} + +void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) { + llvm::GlobalVariable *VTable = getAddrOfVTable(RD, CharUnits()); + if (VTable->hasInitializer()) + return; + + ItaniumVTableContext &VTContext = CGM.getItaniumVTableContext(); + const VTableLayout &VTLayout = VTContext.getVTableLayout(RD); + llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD); + llvm::Constant *RTTI = + CGM.GetAddrOfRTTIDescriptor(CGM.getContext().getTagDeclType(RD)); + + // Create and set the initializer. + llvm::Constant *Init = CGVT.CreateVTableInitializer( + RD, VTLayout.vtable_component_begin(), VTLayout.getNumVTableComponents(), + VTLayout.vtable_thunk_begin(), VTLayout.getNumVTableThunks(), RTTI); + VTable->setInitializer(Init); + + // Set the correct linkage. + VTable->setLinkage(Linkage); + + // Set the right visibility. + CGM.setGlobalVisibility(VTable, RD); + + // If this is the magic class __cxxabiv1::__fundamental_type_info, + // we will emit the typeinfo for the fundamental types. This is the + // same behaviour as GCC. + const DeclContext *DC = RD->getDeclContext(); + if (RD->getIdentifier() && + RD->getIdentifier()->isStr("__fundamental_type_info") && + isa<NamespaceDecl>(DC) && cast<NamespaceDecl>(DC)->getIdentifier() && + cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__cxxabiv1") && + DC->getParent()->isTranslationUnit()) + EmitFundamentalRTTIDescriptors(); +} + +llvm::Value *ItaniumCXXABI::getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base, + const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) { + bool NeedsVTTParam = CGM.getCXXABI().NeedsVTTParameter(CGF.CurGD); + NeedsVirtualOffset = (NeedsVTTParam && NearestVBase); + + llvm::Value *VTableAddressPoint; + if (NeedsVTTParam && (Base.getBase()->getNumVBases() || NearestVBase)) { + // Get the secondary vpointer index. + uint64_t VirtualPointerIndex = + CGM.getVTables().getSecondaryVirtualPointerIndex(VTableClass, Base); + + /// Load the VTT. + llvm::Value *VTT = CGF.LoadCXXVTT(); + if (VirtualPointerIndex) + VTT = CGF.Builder.CreateConstInBoundsGEP1_64(VTT, VirtualPointerIndex); + + // And load the address point from the VTT. + VTableAddressPoint = CGF.Builder.CreateLoad(VTT); + } else { + llvm::Constant *VTable = + CGM.getCXXABI().getAddrOfVTable(VTableClass, CharUnits()); + uint64_t AddressPoint = CGM.getItaniumVTableContext() + .getVTableLayout(VTableClass) + .getAddressPoint(Base); + VTableAddressPoint = + CGF.Builder.CreateConstInBoundsGEP2_64(VTable, 0, AddressPoint); + } + + return VTableAddressPoint; +} + +llvm::Constant *ItaniumCXXABI::getVTableAddressPointForConstExpr( + BaseSubobject Base, const CXXRecordDecl *VTableClass) { + llvm::Constant *VTable = getAddrOfVTable(VTableClass, CharUnits()); + + // Find the appropriate vtable within the vtable group. + uint64_t AddressPoint = CGM.getItaniumVTableContext() + .getVTableLayout(VTableClass) + .getAddressPoint(Base); + llvm::Value *Indices[] = { + llvm::ConstantInt::get(CGM.Int64Ty, 0), + llvm::ConstantInt::get(CGM.Int64Ty, AddressPoint) + }; + + return llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, Indices); +} + +llvm::GlobalVariable *ItaniumCXXABI::getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset) { + assert(VPtrOffset.isZero() && "Itanium ABI only supports zero vptr offsets"); + + llvm::GlobalVariable *&VTable = VTables[RD]; + if (VTable) + return VTable; + + // Queue up this v-table for possible deferred emission. + CGM.addDeferredVTable(RD); + + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + getMangleContext().mangleCXXVTable(RD, Out); + Out.flush(); + StringRef Name = OutName.str(); + + ItaniumVTableContext &VTContext = CGM.getItaniumVTableContext(); + llvm::ArrayType *ArrayType = llvm::ArrayType::get( + CGM.Int8PtrTy, VTContext.getVTableLayout(RD).getNumVTableComponents()); + + VTable = CGM.CreateOrReplaceCXXRuntimeVariable( + Name, ArrayType, llvm::GlobalValue::ExternalLinkage); + VTable->setUnnamedAddr(true); + + if (RD->hasAttr<DLLImportAttr>()) + VTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); + else if (RD->hasAttr<DLLExportAttr>()) + VTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + + return VTable; +} + +llvm::Value *ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF, + GlobalDecl GD, + llvm::Value *This, + llvm::Type *Ty) { + GD = GD.getCanonicalDecl(); + Ty = Ty->getPointerTo()->getPointerTo(); + llvm::Value *VTable = CGF.GetVTablePtr(This, Ty); + + uint64_t VTableIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(GD); + llvm::Value *VFuncPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(VTable, VTableIndex, "vfn"); + return CGF.Builder.CreateLoad(VFuncPtr); +} + +void ItaniumCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, + SourceLocation CallLoc, + llvm::Value *This) { + assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete); + + const CGFunctionInfo *FInfo + = &CGM.getTypes().arrangeCXXDestructor(Dtor, DtorType); + llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo); + llvm::Value *Callee = + getVirtualFunctionPointer(CGF, GlobalDecl(Dtor, DtorType), This, Ty); + + CGF.EmitCXXMemberCall(Dtor, CallLoc, Callee, ReturnValueSlot(), This, + /*ImplicitParam=*/nullptr, QualType(), nullptr, + nullptr); +} + +void ItaniumCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) { + CodeGenVTables &VTables = CGM.getVTables(); + llvm::GlobalVariable *VTT = VTables.GetAddrOfVTT(RD); + VTables.EmitVTTDefinition(VTT, CGM.getVTableLinkage(RD), RD); +} + +static llvm::Value *performTypeAdjustment(CodeGenFunction &CGF, + llvm::Value *Ptr, + int64_t NonVirtualAdjustment, + int64_t VirtualAdjustment, + bool IsReturnAdjustment) { + if (!NonVirtualAdjustment && !VirtualAdjustment) + return Ptr; + + llvm::Type *Int8PtrTy = CGF.Int8PtrTy; + llvm::Value *V = CGF.Builder.CreateBitCast(Ptr, Int8PtrTy); + + if (NonVirtualAdjustment && !IsReturnAdjustment) { + // Perform the non-virtual adjustment for a base-to-derived cast. + V = CGF.Builder.CreateConstInBoundsGEP1_64(V, NonVirtualAdjustment); + } + + if (VirtualAdjustment) { + llvm::Type *PtrDiffTy = + CGF.ConvertType(CGF.getContext().getPointerDiffType()); + + // Perform the virtual adjustment. + llvm::Value *VTablePtrPtr = + CGF.Builder.CreateBitCast(V, Int8PtrTy->getPointerTo()); + + llvm::Value *VTablePtr = CGF.Builder.CreateLoad(VTablePtrPtr); + + llvm::Value *OffsetPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(VTablePtr, VirtualAdjustment); + + OffsetPtr = CGF.Builder.CreateBitCast(OffsetPtr, PtrDiffTy->getPointerTo()); + + // Load the adjustment offset from the vtable. + llvm::Value *Offset = CGF.Builder.CreateLoad(OffsetPtr); + + // Adjust our pointer. + V = CGF.Builder.CreateInBoundsGEP(V, Offset); + } + + if (NonVirtualAdjustment && IsReturnAdjustment) { + // Perform the non-virtual adjustment for a derived-to-base cast. + V = CGF.Builder.CreateConstInBoundsGEP1_64(V, NonVirtualAdjustment); + } + + // Cast back to the original type. + return CGF.Builder.CreateBitCast(V, Ptr->getType()); +} + +llvm::Value *ItaniumCXXABI::performThisAdjustment(CodeGenFunction &CGF, + llvm::Value *This, + const ThisAdjustment &TA) { + return performTypeAdjustment(CGF, This, TA.NonVirtual, + TA.Virtual.Itanium.VCallOffsetOffset, + /*IsReturnAdjustment=*/false); +} + +llvm::Value * +ItaniumCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, + const ReturnAdjustment &RA) { + return performTypeAdjustment(CGF, Ret, RA.NonVirtual, + RA.Virtual.Itanium.VBaseOffsetOffset, + /*IsReturnAdjustment=*/true); +} + +void ARMCXXABI::EmitReturnFromThunk(CodeGenFunction &CGF, + RValue RV, QualType ResultType) { + if (!isa<CXXDestructorDecl>(CGF.CurGD.getDecl())) + return ItaniumCXXABI::EmitReturnFromThunk(CGF, RV, ResultType); + + // Destructor thunks in the ARM ABI have indeterminate results. + llvm::Type *T = + cast<llvm::PointerType>(CGF.ReturnValue->getType())->getElementType(); + RValue Undef = RValue::get(llvm::UndefValue::get(T)); + return ItaniumCXXABI::EmitReturnFromThunk(CGF, Undef, ResultType); +} + +/************************** Array allocation cookies **************************/ + +CharUnits ItaniumCXXABI::getArrayCookieSizeImpl(QualType elementType) { + // The array cookie is a size_t; pad that up to the element alignment. + // The cookie is actually right-justified in that space. + return std::max(CharUnits::fromQuantity(CGM.SizeSizeInBytes), + CGM.getContext().getTypeAlignInChars(elementType)); +} + +llvm::Value *ItaniumCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType) { + assert(requiresArrayCookie(expr)); + + unsigned AS = NewPtr->getType()->getPointerAddressSpace(); + + ASTContext &Ctx = getContext(); + QualType SizeTy = Ctx.getSizeType(); + CharUnits SizeSize = Ctx.getTypeSizeInChars(SizeTy); + + // The size of the cookie. + CharUnits CookieSize = + std::max(SizeSize, Ctx.getTypeAlignInChars(ElementType)); + assert(CookieSize == getArrayCookieSizeImpl(ElementType)); + + // Compute an offset to the cookie. + llvm::Value *CookiePtr = NewPtr; + CharUnits CookieOffset = CookieSize - SizeSize; + if (!CookieOffset.isZero()) + CookiePtr = CGF.Builder.CreateConstInBoundsGEP1_64(CookiePtr, + CookieOffset.getQuantity()); + + // Write the number of elements into the appropriate slot. + llvm::Value *NumElementsPtr + = CGF.Builder.CreateBitCast(CookiePtr, + CGF.ConvertType(SizeTy)->getPointerTo(AS)); + CGF.Builder.CreateStore(NumElements, NumElementsPtr); + + // Finally, compute a pointer to the actual data buffer by skipping + // over the cookie completely. + return CGF.Builder.CreateConstInBoundsGEP1_64(NewPtr, + CookieSize.getQuantity()); +} + +llvm::Value *ItaniumCXXABI::readArrayCookieImpl(CodeGenFunction &CGF, + llvm::Value *allocPtr, + CharUnits cookieSize) { + // The element size is right-justified in the cookie. + llvm::Value *numElementsPtr = allocPtr; + CharUnits numElementsOffset = + cookieSize - CharUnits::fromQuantity(CGF.SizeSizeInBytes); + if (!numElementsOffset.isZero()) + numElementsPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(numElementsPtr, + numElementsOffset.getQuantity()); + + unsigned AS = allocPtr->getType()->getPointerAddressSpace(); + numElementsPtr = + CGF.Builder.CreateBitCast(numElementsPtr, CGF.SizeTy->getPointerTo(AS)); + return CGF.Builder.CreateLoad(numElementsPtr); +} + +CharUnits ARMCXXABI::getArrayCookieSizeImpl(QualType elementType) { + // ARM says that the cookie is always: + // struct array_cookie { + // std::size_t element_size; // element_size != 0 + // std::size_t element_count; + // }; + // But the base ABI doesn't give anything an alignment greater than + // 8, so we can dismiss this as typical ABI-author blindness to + // actual language complexity and round up to the element alignment. + return std::max(CharUnits::fromQuantity(2 * CGM.SizeSizeInBytes), + CGM.getContext().getTypeAlignInChars(elementType)); +} + +llvm::Value *ARMCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *newPtr, + llvm::Value *numElements, + const CXXNewExpr *expr, + QualType elementType) { + assert(requiresArrayCookie(expr)); + + // NewPtr is a char*, but we generalize to arbitrary addrspaces. + unsigned AS = newPtr->getType()->getPointerAddressSpace(); + + // The cookie is always at the start of the buffer. + llvm::Value *cookie = newPtr; + + // The first element is the element size. + cookie = CGF.Builder.CreateBitCast(cookie, CGF.SizeTy->getPointerTo(AS)); + llvm::Value *elementSize = llvm::ConstantInt::get(CGF.SizeTy, + getContext().getTypeSizeInChars(elementType).getQuantity()); + CGF.Builder.CreateStore(elementSize, cookie); + + // The second element is the element count. + cookie = CGF.Builder.CreateConstInBoundsGEP1_32(cookie, 1); + CGF.Builder.CreateStore(numElements, cookie); + + // Finally, compute a pointer to the actual data buffer by skipping + // over the cookie completely. + CharUnits cookieSize = ARMCXXABI::getArrayCookieSizeImpl(elementType); + return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr, + cookieSize.getQuantity()); +} + +llvm::Value *ARMCXXABI::readArrayCookieImpl(CodeGenFunction &CGF, + llvm::Value *allocPtr, + CharUnits cookieSize) { + // The number of elements is at offset sizeof(size_t) relative to + // the allocated pointer. + llvm::Value *numElementsPtr + = CGF.Builder.CreateConstInBoundsGEP1_64(allocPtr, CGF.SizeSizeInBytes); + + unsigned AS = allocPtr->getType()->getPointerAddressSpace(); + numElementsPtr = + CGF.Builder.CreateBitCast(numElementsPtr, CGF.SizeTy->getPointerTo(AS)); + return CGF.Builder.CreateLoad(numElementsPtr); +} + +/*********************** Static local initialization **************************/ + +static llvm::Constant *getGuardAcquireFn(CodeGenModule &CGM, + llvm::PointerType *GuardPtrTy) { + // int __cxa_guard_acquire(__guard *guard_object); + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.getTypes().ConvertType(CGM.getContext().IntTy), + GuardPtrTy, /*isVarArg=*/false); + return CGM.CreateRuntimeFunction(FTy, "__cxa_guard_acquire", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +static llvm::Constant *getGuardReleaseFn(CodeGenModule &CGM, + llvm::PointerType *GuardPtrTy) { + // void __cxa_guard_release(__guard *guard_object); + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, GuardPtrTy, /*isVarArg=*/false); + return CGM.CreateRuntimeFunction(FTy, "__cxa_guard_release", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +static llvm::Constant *getGuardAbortFn(CodeGenModule &CGM, + llvm::PointerType *GuardPtrTy) { + // void __cxa_guard_abort(__guard *guard_object); + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, GuardPtrTy, /*isVarArg=*/false); + return CGM.CreateRuntimeFunction(FTy, "__cxa_guard_abort", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +namespace { + struct CallGuardAbort : EHScopeStack::Cleanup { + llvm::GlobalVariable *Guard; + CallGuardAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + CGF.EmitNounwindRuntimeCall(getGuardAbortFn(CGF.CGM, Guard->getType()), + Guard); + } + }; +} + +/// The ARM code here follows the Itanium code closely enough that we +/// just special-case it at particular places. +void ItaniumCXXABI::EmitGuardedInit(CodeGenFunction &CGF, + const VarDecl &D, + llvm::GlobalVariable *var, + bool shouldPerformInit) { + CGBuilderTy &Builder = CGF.Builder; + + // We only need to use thread-safe statics for local non-TLS variables; + // global initialization is always single-threaded. + bool threadsafe = getContext().getLangOpts().ThreadsafeStatics && + D.isLocalVarDecl() && !D.getTLSKind(); + + // If we have a global variable with internal linkage and thread-safe statics + // are disabled, we can just let the guard variable be of type i8. + bool useInt8GuardVariable = !threadsafe && var->hasInternalLinkage(); + + llvm::IntegerType *guardTy; + if (useInt8GuardVariable) { + guardTy = CGF.Int8Ty; + } else { + // Guard variables are 64 bits in the generic ABI and size width on ARM + // (i.e. 32-bit on AArch32, 64-bit on AArch64). + guardTy = (UseARMGuardVarABI ? CGF.SizeTy : CGF.Int64Ty); + } + llvm::PointerType *guardPtrTy = guardTy->getPointerTo(); + + // Create the guard variable if we don't already have it (as we + // might if we're double-emitting this function body). + llvm::GlobalVariable *guard = CGM.getStaticLocalDeclGuardAddress(&D); + if (!guard) { + // Mangle the name for the guard. + SmallString<256> guardName; + { + llvm::raw_svector_ostream out(guardName); + getMangleContext().mangleStaticGuardVariable(&D, out); + out.flush(); + } + + // Create the guard variable with a zero-initializer. + // Just absorb linkage and visibility from the guarded variable. + guard = new llvm::GlobalVariable(CGM.getModule(), guardTy, + false, var->getLinkage(), + llvm::ConstantInt::get(guardTy, 0), + guardName.str()); + guard->setVisibility(var->getVisibility()); + // If the variable is thread-local, so is its guard variable. + guard->setThreadLocalMode(var->getThreadLocalMode()); + + CGM.setStaticLocalDeclGuardAddress(&D, guard); + } + + // Test whether the variable has completed initialization. + // + // Itanium C++ ABI 3.3.2: + // The following is pseudo-code showing how these functions can be used: + // if (obj_guard.first_byte == 0) { + // if ( __cxa_guard_acquire (&obj_guard) ) { + // try { + // ... initialize the object ...; + // } catch (...) { + // __cxa_guard_abort (&obj_guard); + // throw; + // } + // ... queue object destructor with __cxa_atexit() ...; + // __cxa_guard_release (&obj_guard); + // } + // } + + // Load the first byte of the guard variable. + llvm::LoadInst *LI = + Builder.CreateLoad(Builder.CreateBitCast(guard, CGM.Int8PtrTy)); + LI->setAlignment(1); + + // Itanium ABI: + // An implementation supporting thread-safety on multiprocessor + // systems must also guarantee that references to the initialized + // object do not occur before the load of the initialization flag. + // + // In LLVM, we do this by marking the load Acquire. + if (threadsafe) + LI->setAtomic(llvm::Acquire); + + // For ARM, we should only check the first bit, rather than the entire byte: + // + // ARM C++ ABI 3.2.3.1: + // To support the potential use of initialization guard variables + // as semaphores that are the target of ARM SWP and LDREX/STREX + // synchronizing instructions we define a static initialization + // guard variable to be a 4-byte aligned, 4-byte word with the + // following inline access protocol. + // #define INITIALIZED 1 + // if ((obj_guard & INITIALIZED) != INITIALIZED) { + // if (__cxa_guard_acquire(&obj_guard)) + // ... + // } + // + // and similarly for ARM64: + // + // ARM64 C++ ABI 3.2.2: + // This ABI instead only specifies the value bit 0 of the static guard + // variable; all other bits are platform defined. Bit 0 shall be 0 when the + // variable is not initialized and 1 when it is. + llvm::Value *V = + (UseARMGuardVarABI && !useInt8GuardVariable) + ? Builder.CreateAnd(LI, llvm::ConstantInt::get(CGM.Int8Ty, 1)) + : LI; + llvm::Value *isInitialized = Builder.CreateIsNull(V, "guard.uninitialized"); + + llvm::BasicBlock *InitCheckBlock = CGF.createBasicBlock("init.check"); + llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end"); + + // Check if the first byte of the guard variable is zero. + Builder.CreateCondBr(isInitialized, InitCheckBlock, EndBlock); + + CGF.EmitBlock(InitCheckBlock); + + // Variables used when coping with thread-safe statics and exceptions. + if (threadsafe) { + // Call __cxa_guard_acquire. + llvm::Value *V + = CGF.EmitNounwindRuntimeCall(getGuardAcquireFn(CGM, guardPtrTy), guard); + + llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init"); + + Builder.CreateCondBr(Builder.CreateIsNotNull(V, "tobool"), + InitBlock, EndBlock); + + // Call __cxa_guard_abort along the exceptional edge. + CGF.EHStack.pushCleanup<CallGuardAbort>(EHCleanup, guard); + + CGF.EmitBlock(InitBlock); + } + + // Emit the initializer and add a global destructor if appropriate. + CGF.EmitCXXGlobalVarDeclInit(D, var, shouldPerformInit); + + if (threadsafe) { + // Pop the guard-abort cleanup if we pushed one. + CGF.PopCleanupBlock(); + + // Call __cxa_guard_release. This cannot throw. + CGF.EmitNounwindRuntimeCall(getGuardReleaseFn(CGM, guardPtrTy), guard); + } else { + Builder.CreateStore(llvm::ConstantInt::get(guardTy, 1), guard); + } + + CGF.EmitBlock(EndBlock); +} + +/// Register a global destructor using __cxa_atexit. +static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF, + llvm::Constant *dtor, + llvm::Constant *addr, + bool TLS) { + const char *Name = "__cxa_atexit"; + if (TLS) { + const llvm::Triple &T = CGF.getTarget().getTriple(); + Name = T.isMacOSX() ? "_tlv_atexit" : "__cxa_thread_atexit"; + } + + // We're assuming that the destructor function is something we can + // reasonably call with the default CC. Go ahead and cast it to the + // right prototype. + llvm::Type *dtorTy = + llvm::FunctionType::get(CGF.VoidTy, CGF.Int8PtrTy, false)->getPointerTo(); + + // extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d); + llvm::Type *paramTys[] = { dtorTy, CGF.Int8PtrTy, CGF.Int8PtrTy }; + llvm::FunctionType *atexitTy = + llvm::FunctionType::get(CGF.IntTy, paramTys, false); + + // Fetch the actual function. + llvm::Constant *atexit = CGF.CGM.CreateRuntimeFunction(atexitTy, Name); + if (llvm::Function *fn = dyn_cast<llvm::Function>(atexit)) + fn->setDoesNotThrow(); + + // Create a variable that binds the atexit to this shared object. + llvm::Constant *handle = + CGF.CGM.CreateRuntimeVariable(CGF.Int8Ty, "__dso_handle"); + + llvm::Value *args[] = { + llvm::ConstantExpr::getBitCast(dtor, dtorTy), + llvm::ConstantExpr::getBitCast(addr, CGF.Int8PtrTy), + handle + }; + CGF.EmitNounwindRuntimeCall(atexit, args); +} + +/// Register a global destructor as best as we know how. +void ItaniumCXXABI::registerGlobalDtor(CodeGenFunction &CGF, + const VarDecl &D, + llvm::Constant *dtor, + llvm::Constant *addr) { + // Use __cxa_atexit if available. + if (CGM.getCodeGenOpts().CXAAtExit) + return emitGlobalDtorWithCXAAtExit(CGF, dtor, addr, D.getTLSKind()); + + if (D.getTLSKind()) + CGM.ErrorUnsupported(&D, "non-trivial TLS destruction"); + + // In Apple kexts, we want to add a global destructor entry. + // FIXME: shouldn't this be guarded by some variable? + if (CGM.getLangOpts().AppleKext) { + // Generate a global destructor entry. + return CGM.AddCXXDtorEntry(dtor, addr); + } + + CGF.registerGlobalDtorWithAtExit(D, dtor, addr); +} + +static bool isThreadWrapperReplaceable(const VarDecl *VD, + CodeGen::CodeGenModule &CGM) { + assert(!VD->isStaticLocal() && "static local VarDecls don't need wrappers!"); + // OS X prefers to have references to thread local variables to go through + // the thread wrapper instead of directly referencing the backing variable. + return VD->getTLSKind() == VarDecl::TLS_Dynamic && + CGM.getTarget().getTriple().isMacOSX(); +} + +/// Get the appropriate linkage for the wrapper function. This is essentially +/// the weak form of the variable's linkage; every translation unit which needs +/// the wrapper emits a copy, and we want the linker to merge them. +static llvm::GlobalValue::LinkageTypes +getThreadLocalWrapperLinkage(const VarDecl *VD, CodeGen::CodeGenModule &CGM) { + llvm::GlobalValue::LinkageTypes VarLinkage = + CGM.getLLVMLinkageVarDefinition(VD, /*isConstant=*/false); + + // For internal linkage variables, we don't need an external or weak wrapper. + if (llvm::GlobalValue::isLocalLinkage(VarLinkage)) + return VarLinkage; + + // If the thread wrapper is replaceable, give it appropriate linkage. + if (isThreadWrapperReplaceable(VD, CGM)) { + if (llvm::GlobalVariable::isLinkOnceLinkage(VarLinkage) || + llvm::GlobalVariable::isWeakODRLinkage(VarLinkage)) + return llvm::GlobalVariable::WeakAnyLinkage; + return VarLinkage; + } + return llvm::GlobalValue::WeakODRLinkage; +} + +llvm::Function * +ItaniumCXXABI::getOrCreateThreadLocalWrapper(const VarDecl *VD, + llvm::GlobalVariable *Var) { + // Mangle the name for the thread_local wrapper function. + SmallString<256> WrapperName; + { + llvm::raw_svector_ostream Out(WrapperName); + getMangleContext().mangleItaniumThreadLocalWrapper(VD, Out); + Out.flush(); + } + + if (llvm::Value *V = Var->getParent()->getNamedValue(WrapperName)) + return cast<llvm::Function>(V); + + llvm::Type *RetTy = Var->getType(); + if (VD->getType()->isReferenceType()) + RetTy = RetTy->getPointerElementType(); + + llvm::FunctionType *FnTy = llvm::FunctionType::get(RetTy, false); + llvm::Function *Wrapper = + llvm::Function::Create(FnTy, getThreadLocalWrapperLinkage(VD, CGM), + WrapperName.str(), &CGM.getModule()); + // Always resolve references to the wrapper at link time. + if (!Wrapper->hasLocalLinkage() && !isThreadWrapperReplaceable(VD, CGM)) + Wrapper->setVisibility(llvm::GlobalValue::HiddenVisibility); + return Wrapper; +} + +void ItaniumCXXABI::EmitThreadLocalInitFuncs( + ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls, + llvm::Function *InitFunc) { + for (unsigned I = 0, N = Decls.size(); I != N; ++I) { + const VarDecl *VD = Decls[I].first; + llvm::GlobalVariable *Var = Decls[I].second; + + // Some targets require that all access to thread local variables go through + // the thread wrapper. This means that we cannot attempt to create a thread + // wrapper or a thread helper. + if (isThreadWrapperReplaceable(VD, CGM) && !VD->hasDefinition()) + continue; + + // Mangle the name for the thread_local initialization function. + SmallString<256> InitFnName; + { + llvm::raw_svector_ostream Out(InitFnName); + getMangleContext().mangleItaniumThreadLocalInit(VD, Out); + Out.flush(); + } + + // If we have a definition for the variable, emit the initialization + // function as an alias to the global Init function (if any). Otherwise, + // produce a declaration of the initialization function. + llvm::GlobalValue *Init = nullptr; + bool InitIsInitFunc = false; + if (VD->hasDefinition()) { + InitIsInitFunc = true; + if (InitFunc) + Init = llvm::GlobalAlias::create(Var->getLinkage(), InitFnName.str(), + InitFunc); + } else { + // Emit a weak global function referring to the initialization function. + // This function will not exist if the TU defining the thread_local + // variable in question does not need any dynamic initialization for + // its thread_local variables. + llvm::FunctionType *FnTy = llvm::FunctionType::get(CGM.VoidTy, false); + Init = llvm::Function::Create( + FnTy, llvm::GlobalVariable::ExternalWeakLinkage, InitFnName.str(), + &CGM.getModule()); + } + + if (Init) + Init->setVisibility(Var->getVisibility()); + + llvm::Function *Wrapper = getOrCreateThreadLocalWrapper(VD, Var); + llvm::LLVMContext &Context = CGM.getModule().getContext(); + llvm::BasicBlock *Entry = llvm::BasicBlock::Create(Context, "", Wrapper); + CGBuilderTy Builder(Entry); + if (InitIsInitFunc) { + if (Init) + Builder.CreateCall(Init); + } else { + // Don't know whether we have an init function. Call it if it exists. + llvm::Value *Have = Builder.CreateIsNotNull(Init); + llvm::BasicBlock *InitBB = llvm::BasicBlock::Create(Context, "", Wrapper); + llvm::BasicBlock *ExitBB = llvm::BasicBlock::Create(Context, "", Wrapper); + Builder.CreateCondBr(Have, InitBB, ExitBB); + + Builder.SetInsertPoint(InitBB); + Builder.CreateCall(Init); + Builder.CreateBr(ExitBB); + + Builder.SetInsertPoint(ExitBB); + } + + // For a reference, the result of the wrapper function is a pointer to + // the referenced object. + llvm::Value *Val = Var; + if (VD->getType()->isReferenceType()) { + llvm::LoadInst *LI = Builder.CreateLoad(Val); + LI->setAlignment(CGM.getContext().getDeclAlign(VD).getQuantity()); + Val = LI; + } + + Builder.CreateRet(Val); + } +} + +LValue ItaniumCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, + const VarDecl *VD, + QualType LValType) { + QualType T = VD->getType(); + llvm::Type *Ty = CGF.getTypes().ConvertTypeForMem(T); + llvm::Value *Val = CGF.CGM.GetAddrOfGlobalVar(VD, Ty); + llvm::Function *Wrapper = + getOrCreateThreadLocalWrapper(VD, cast<llvm::GlobalVariable>(Val)); + + Val = CGF.Builder.CreateCall(Wrapper); + + LValue LV; + if (VD->getType()->isReferenceType()) + LV = CGF.MakeNaturalAlignAddrLValue(Val, LValType); + else + LV = CGF.MakeAddrLValue(Val, LValType, CGF.getContext().getDeclAlign(VD)); + // FIXME: need setObjCGCLValueClass? + return LV; +} + +/// Return whether the given global decl needs a VTT parameter, which it does +/// if it's a base constructor or destructor with virtual bases. +bool ItaniumCXXABI::NeedsVTTParameter(GlobalDecl GD) { + const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl()); + + // We don't have any virtual bases, just return early. + if (!MD->getParent()->getNumVBases()) + return false; + + // Check if we have a base constructor. + if (isa<CXXConstructorDecl>(MD) && GD.getCtorType() == Ctor_Base) + return true; + + // Check if we have a base destructor. + if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base) + return true; + + 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; +} |
