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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp')
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1 files changed, 1674 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 000000000000..0e8f31a48454 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/ItaniumCXXABI.cpp @@ -0,0 +1,1674 @@ +//===------- 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/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 isReturnTypeIndirect(const CXXRecordDecl *RD) const { + // Structures with either a non-trivial destructor or a non-trivial + // copy constructor are always indirect. + return !RD->hasTrivialDestructor() || RD->hasNonTrivialCopyConstructor(); + } + + RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const { + // Structures with either a non-trivial destructor or a non-trivial + // copy constructor are always indirect. + if (!RD->hasTrivialDestructor() || RD->hasNonTrivialCopyConstructor()) + return RAA_Indirect; + return RAA_Default; + } + + bool isZeroInitializable(const MemberPointerType *MPT); + + llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT); + + llvm::Value *EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, + llvm::Value *&This, + llvm::Value *MemFnPtr, + const MemberPointerType *MPT); + + llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF, + llvm::Value *Base, + llvm::Value *MemPtr, + const MemberPointerType *MPT); + + llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src); + llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src); + + llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); + + llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD); + llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset); + llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); + llvm::Constant *BuildMemberPointer(const CXXMethodDecl *MD, + CharUnits ThisAdjustment); + + llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, + llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality); + + llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *Addr, + const MemberPointerType *MPT); + + llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF, + llvm::Value *ptr, + QualType type); + + llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, + llvm::Value *This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl); + + void BuildConstructorSignature(const CXXConstructorDecl *Ctor, + CXXCtorType T, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys); + + void EmitCXXConstructors(const CXXConstructorDecl *D); + + void BuildDestructorSignature(const CXXDestructorDecl *Dtor, + CXXDtorType T, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys); + + bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, + CXXDtorType DT) const { + // 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); + + void BuildInstanceFunctionParams(CodeGenFunction &CGF, + QualType &ResTy, + FunctionArgList &Params); + + void EmitInstanceFunctionProlog(CodeGenFunction &CGF); + + void EmitConstructorCall(CodeGenFunction &CGF, + const CXXConstructorDecl *D, CXXCtorType Type, + bool ForVirtualBase, bool Delegating, + llvm::Value *This, + CallExpr::const_arg_iterator ArgBeg, + CallExpr::const_arg_iterator ArgEnd); + + void emitVTableDefinitions(CodeGenVTables &CGVT, const CXXRecordDecl *RD); + + llvm::Value *getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, + BaseSubobject Base, const CXXRecordDecl *NearestVBase, + bool &NeedsVirtualOffset); + + llvm::Constant * + getVTableAddressPointForConstExpr(BaseSubobject Base, + const CXXRecordDecl *VTableClass); + + llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset); + + llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD, + llvm::Value *This, llvm::Type *Ty); + + void EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, SourceLocation CallLoc, + llvm::Value *This); + + void emitVirtualInheritanceTables(const CXXRecordDecl *RD); + + void setThunkLinkage(llvm::Function *Thunk, bool ForVTable) { + // 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); + + llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, + const ReturnAdjustment &RA); + + StringRef GetPureVirtualCallName() { return "__cxa_pure_virtual"; } + StringRef GetDeletedVirtualCallName() { return "__cxa_deleted_virtual"; } + + CharUnits getArrayCookieSizeImpl(QualType elementType); + llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType); + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, + llvm::Value *allocPtr, + CharUnits cookieSize); + + void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *DeclPtr, bool PerformInit); + void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, + llvm::Constant *dtor, llvm::Constant *addr); + + llvm::Function *getOrCreateThreadLocalWrapper(const VarDecl *VD, + llvm::GlobalVariable *Var); + void EmitThreadLocalInitFuncs( + llvm::ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls, + llvm::Function *InitFunc); + LValue EmitThreadLocalDeclRefExpr(CodeGenFunction &CGF, + const DeclRefExpr *DRE); + + bool NeedsVTTParameter(GlobalDecl GD); +}; + +class ARMCXXABI : public ItaniumCXXABI { +public: + ARMCXXABI(CodeGen::CodeGenModule &CGM) : + ItaniumCXXABI(CGM, /* UseARMMethodPtrABI = */ true, + /* UseARMGuardVarABI = */ true) {} + + bool HasThisReturn(GlobalDecl GD) const { + return (isa<CXXConstructorDecl>(GD.getDecl()) || ( + isa<CXXDestructorDecl>(GD.getDecl()) && + GD.getDtorType() != Dtor_Deleting)); + } + + void EmitReturnFromThunk(CodeGenFunction &CGF, RValue RV, QualType ResTy); + + CharUnits getArrayCookieSizeImpl(QualType elementType); + llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType); + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, llvm::Value *allocPtr, + CharUnits cookieSize); +}; +} + +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); + + // 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, + 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 = Builder.CreateBitCast(This, VTableTy->getPointerTo()); + VTable = Builder.CreateLoad(VTable, "memptr.vtable"); + + // 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, + 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; +} + +/// 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); +} + +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(); + + // 'this' parameter is already there, as well as 'this' return if + // HasThisReturn(GlobalDecl(Ctor, Type)) is true + + // Check if we need to add a VTT parameter (which has type void **). + if (Type == Ctor_Base && Ctor->getParent()->getNumVBases() != 0) + ArgTys.push_back(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 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 constructor used for constructing this as a base class; + // ignores virtual bases. + CGM.EmitGlobal(GlobalDecl(D, Ctor_Base)); +} + +/// 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 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)); + + // 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 used for destructing this as a base class; ignores + // virtual bases. + CGM.EmitGlobal(GlobalDecl(D, Dtor_Base)); +} + +void ItaniumCXXABI::BuildInstanceFunctionParams(CodeGenFunction &CGF, + QualType &ResTy, + FunctionArgList &Params) { + /// Create the 'this' variable. + BuildThisParam(CGF, Params); + + const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); + assert(MD->isInstance()); + + // 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, 0, MD->getLocation(), + &Context.Idents.get("vtt"), T); + Params.push_back(VTTDecl); + getVTTDecl(CGF) = VTTDecl; + } +} + +void ItaniumCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) { + /// Initialize the 'this' slot. + EmitThisParam(CGF); + + /// Initialize the 'vtt' slot if needed. + if (getVTTDecl(CGF)) { + getVTTValue(CGF) + = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(getVTTDecl(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); +} + +void ItaniumCXXABI::EmitConstructorCall(CodeGenFunction &CGF, + const CXXConstructorDecl *D, + CXXCtorType Type, + bool ForVirtualBase, bool Delegating, + llvm::Value *This, + CallExpr::const_arg_iterator ArgBeg, + CallExpr::const_arg_iterator ArgEnd) { + llvm::Value *VTT = CGF.GetVTTParameter(GlobalDecl(D, Type), ForVirtualBase, + Delegating); + QualType VTTTy = getContext().getPointerType(getContext().VoidPtrTy); + llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type); + + // FIXME: Provide a source location here. + CGF.EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), + This, VTT, VTTTy, ArgBeg, ArgEnd); +} + +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); + + // Create and set the initializer. + llvm::Constant *Init = CGVT.CreateVTableInitializer( + RD, VTLayout.vtable_component_begin(), VTLayout.getNumVTableComponents(), + VTLayout.vtable_thunk_begin(), VTLayout.getNumVTableThunks()); + VTable->setInitializer(Init); + + // Set the correct linkage. + VTable->setLinkage(Linkage); + + // Set the right visibility. + CGM.setTypeVisibility(VTable, RD, CodeGenModule::TVK_ForVTable); + + // 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()) + CGM.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); + 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=*/0, QualType(), 0, 0); +} + +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) { + 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. + llvm::Value *isInitialized; + + // 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)) + // ... + // } + if (UseARMGuardVarABI && !useInt8GuardVariable) { + llvm::Value *V = Builder.CreateLoad(guard); + llvm::Value *Test1 = llvm::ConstantInt::get(guardTy, 1); + V = Builder.CreateAnd(V, Test1); + isInitialized = Builder.CreateIsNull(V, "guard.uninitialized"); + + // 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); + // } + // } + } else { + // 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); + + isInitialized = Builder.CreateIsNull(LI, "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); +} + +/// Get the appropriate linkage for the wrapper function. This is essentially +/// the weak form of the variable's linkage; every translation unit which wneeds +/// the wrapper emits a copy, and we want the linker to merge them. +static llvm::GlobalValue::LinkageTypes getThreadLocalWrapperLinkage( + llvm::GlobalValue::LinkageTypes VarLinkage) { + if (llvm::GlobalValue::isLinkerPrivateLinkage(VarLinkage)) + return llvm::GlobalValue::LinkerPrivateWeakLinkage; + // For internal linkage variables, we don't need an external or weak wrapper. + if (llvm::GlobalValue::isLocalLinkage(VarLinkage)) + 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(Var->getLinkage()), WrapperName.str(), + &CGM.getModule()); + // Always resolve references to the wrapper at link time. + Wrapper->setVisibility(llvm::GlobalValue::HiddenVisibility); + return Wrapper; +} + +void ItaniumCXXABI::EmitThreadLocalInitFuncs( + llvm::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; + + // 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 = 0; + bool InitIsInitFunc = false; + if (VD->hasDefinition()) { + InitIsInitFunc = true; + if (InitFunc) + Init = + new llvm::GlobalAlias(InitFunc->getType(), Var->getLinkage(), + InitFnName.str(), InitFunc, &CGM.getModule()); + } 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::EmitThreadLocalDeclRefExpr(CodeGenFunction &CGF, + const DeclRefExpr *DRE) { + const VarDecl *VD = cast<VarDecl>(DRE->getDecl()); + 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, T); + else + LV = CGF.MakeAddrLValue(Val, DRE->getType(), + 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; +} |