| //===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This contains code to emit Constant Expr nodes as LLVM code. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CodeGenFunction.h" |
| #include "CGCXXABI.h" |
| #include "CGObjCRuntime.h" |
| #include "CGRecordLayout.h" |
| #include "CodeGenModule.h" |
| #include "clang/AST/APValue.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/RecordLayout.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/Basic/Builtins.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/GlobalVariable.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| //===----------------------------------------------------------------------===// |
| // ConstStructBuilder |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class ConstStructBuilder { |
| CodeGenModule &CGM; |
| CodeGenFunction *CGF; |
| |
| bool Packed; |
| CharUnits NextFieldOffsetInChars; |
| CharUnits LLVMStructAlignment; |
| SmallVector<llvm::Constant *, 32> Elements; |
| public: |
| static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, |
| InitListExpr *ILE); |
| static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, |
| const APValue &Value, QualType ValTy); |
| |
| private: |
| ConstStructBuilder(CodeGenModule &CGM, CodeGenFunction *CGF) |
| : CGM(CGM), CGF(CGF), Packed(false), |
| NextFieldOffsetInChars(CharUnits::Zero()), |
| LLVMStructAlignment(CharUnits::One()) { } |
| |
| void AppendVTablePointer(BaseSubobject Base, llvm::Constant *VTable, |
| const CXXRecordDecl *VTableClass); |
| |
| void AppendField(const FieldDecl *Field, uint64_t FieldOffset, |
| llvm::Constant *InitExpr); |
| |
| void AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst); |
| |
| void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset, |
| llvm::ConstantInt *InitExpr); |
| |
| void AppendPadding(CharUnits PadSize); |
| |
| void AppendTailPadding(CharUnits RecordSize); |
| |
| void ConvertStructToPacked(); |
| |
| bool Build(InitListExpr *ILE); |
| void Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase, |
| llvm::Constant *VTable, const CXXRecordDecl *VTableClass, |
| CharUnits BaseOffset); |
| llvm::Constant *Finalize(QualType Ty); |
| |
| CharUnits getAlignment(const llvm::Constant *C) const { |
| if (Packed) return CharUnits::One(); |
| return CharUnits::fromQuantity( |
| CGM.getDataLayout().getABITypeAlignment(C->getType())); |
| } |
| |
| CharUnits getSizeInChars(const llvm::Constant *C) const { |
| return CharUnits::fromQuantity( |
| CGM.getDataLayout().getTypeAllocSize(C->getType())); |
| } |
| }; |
| |
| void ConstStructBuilder::AppendVTablePointer(BaseSubobject Base, |
| llvm::Constant *VTable, |
| const CXXRecordDecl *VTableClass) { |
| // Find the appropriate vtable within the vtable group. |
| uint64_t AddressPoint = |
| CGM.getVTableContext().getVTableLayout(VTableClass).getAddressPoint(Base); |
| llvm::Value *Indices[] = { |
| llvm::ConstantInt::get(CGM.Int64Ty, 0), |
| llvm::ConstantInt::get(CGM.Int64Ty, AddressPoint) |
| }; |
| llvm::Constant *VTableAddressPoint = |
| llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, Indices); |
| |
| // Add the vtable at the start of the object. |
| AppendBytes(Base.getBaseOffset(), VTableAddressPoint); |
| } |
| |
| void ConstStructBuilder:: |
| AppendField(const FieldDecl *Field, uint64_t FieldOffset, |
| llvm::Constant *InitCst) { |
| const ASTContext &Context = CGM.getContext(); |
| |
| CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset); |
| |
| AppendBytes(FieldOffsetInChars, InitCst); |
| } |
| |
| void ConstStructBuilder:: |
| AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst) { |
| |
| assert(NextFieldOffsetInChars <= FieldOffsetInChars |
| && "Field offset mismatch!"); |
| |
| CharUnits FieldAlignment = getAlignment(InitCst); |
| |
| // Round up the field offset to the alignment of the field type. |
| CharUnits AlignedNextFieldOffsetInChars = |
| NextFieldOffsetInChars.RoundUpToAlignment(FieldAlignment); |
| |
| if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) { |
| assert(!Packed && "Alignment is wrong even with a packed struct!"); |
| |
| // Convert the struct to a packed struct. |
| ConvertStructToPacked(); |
| |
| AlignedNextFieldOffsetInChars = NextFieldOffsetInChars; |
| } |
| |
| if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) { |
| // We need to append padding. |
| AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars); |
| |
| assert(NextFieldOffsetInChars == FieldOffsetInChars && |
| "Did not add enough padding!"); |
| |
| AlignedNextFieldOffsetInChars = NextFieldOffsetInChars; |
| } |
| |
| // Add the field. |
| Elements.push_back(InitCst); |
| NextFieldOffsetInChars = AlignedNextFieldOffsetInChars + |
| getSizeInChars(InitCst); |
| |
| if (Packed) |
| assert(LLVMStructAlignment == CharUnits::One() && |
| "Packed struct not byte-aligned!"); |
| else |
| LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment); |
| } |
| |
| void ConstStructBuilder::AppendBitField(const FieldDecl *Field, |
| uint64_t FieldOffset, |
| llvm::ConstantInt *CI) { |
| const ASTContext &Context = CGM.getContext(); |
| const uint64_t CharWidth = Context.getCharWidth(); |
| uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars); |
| if (FieldOffset > NextFieldOffsetInBits) { |
| // We need to add padding. |
| CharUnits PadSize = Context.toCharUnitsFromBits( |
| llvm::RoundUpToAlignment(FieldOffset - NextFieldOffsetInBits, |
| Context.getTargetInfo().getCharAlign())); |
| |
| AppendPadding(PadSize); |
| } |
| |
| uint64_t FieldSize = Field->getBitWidthValue(Context); |
| |
| llvm::APInt FieldValue = CI->getValue(); |
| |
| // Promote the size of FieldValue if necessary |
| // FIXME: This should never occur, but currently it can because initializer |
| // constants are cast to bool, and because clang is not enforcing bitfield |
| // width limits. |
| if (FieldSize > FieldValue.getBitWidth()) |
| FieldValue = FieldValue.zext(FieldSize); |
| |
| // Truncate the size of FieldValue to the bit field size. |
| if (FieldSize < FieldValue.getBitWidth()) |
| FieldValue = FieldValue.trunc(FieldSize); |
| |
| NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars); |
| if (FieldOffset < NextFieldOffsetInBits) { |
| // Either part of the field or the entire field can go into the previous |
| // byte. |
| assert(!Elements.empty() && "Elements can't be empty!"); |
| |
| unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset; |
| |
| bool FitsCompletelyInPreviousByte = |
| BitsInPreviousByte >= FieldValue.getBitWidth(); |
| |
| llvm::APInt Tmp = FieldValue; |
| |
| if (!FitsCompletelyInPreviousByte) { |
| unsigned NewFieldWidth = FieldSize - BitsInPreviousByte; |
| |
| if (CGM.getDataLayout().isBigEndian()) { |
| Tmp = Tmp.lshr(NewFieldWidth); |
| Tmp = Tmp.trunc(BitsInPreviousByte); |
| |
| // We want the remaining high bits. |
| FieldValue = FieldValue.trunc(NewFieldWidth); |
| } else { |
| Tmp = Tmp.trunc(BitsInPreviousByte); |
| |
| // We want the remaining low bits. |
| FieldValue = FieldValue.lshr(BitsInPreviousByte); |
| FieldValue = FieldValue.trunc(NewFieldWidth); |
| } |
| } |
| |
| Tmp = Tmp.zext(CharWidth); |
| if (CGM.getDataLayout().isBigEndian()) { |
| if (FitsCompletelyInPreviousByte) |
| Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth()); |
| } else { |
| Tmp = Tmp.shl(CharWidth - BitsInPreviousByte); |
| } |
| |
| // 'or' in the bits that go into the previous byte. |
| llvm::Value *LastElt = Elements.back(); |
| if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(LastElt)) |
| Tmp |= Val->getValue(); |
| else { |
| assert(isa<llvm::UndefValue>(LastElt)); |
| // If there is an undef field that we're adding to, it can either be a |
| // scalar undef (in which case, we just replace it with our field) or it |
| // is an array. If it is an array, we have to pull one byte off the |
| // array so that the other undef bytes stay around. |
| if (!isa<llvm::IntegerType>(LastElt->getType())) { |
| // The undef padding will be a multibyte array, create a new smaller |
| // padding and then an hole for our i8 to get plopped into. |
| assert(isa<llvm::ArrayType>(LastElt->getType()) && |
| "Expected array padding of undefs"); |
| llvm::ArrayType *AT = cast<llvm::ArrayType>(LastElt->getType()); |
| assert(AT->getElementType()->isIntegerTy(CharWidth) && |
| AT->getNumElements() != 0 && |
| "Expected non-empty array padding of undefs"); |
| |
| // Remove the padding array. |
| NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements()); |
| Elements.pop_back(); |
| |
| // Add the padding back in two chunks. |
| AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1)); |
| AppendPadding(CharUnits::One()); |
| assert(isa<llvm::UndefValue>(Elements.back()) && |
| Elements.back()->getType()->isIntegerTy(CharWidth) && |
| "Padding addition didn't work right"); |
| } |
| } |
| |
| Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp); |
| |
| if (FitsCompletelyInPreviousByte) |
| return; |
| } |
| |
| while (FieldValue.getBitWidth() > CharWidth) { |
| llvm::APInt Tmp; |
| |
| if (CGM.getDataLayout().isBigEndian()) { |
| // We want the high bits. |
| Tmp = |
| FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth); |
| } else { |
| // We want the low bits. |
| Tmp = FieldValue.trunc(CharWidth); |
| |
| FieldValue = FieldValue.lshr(CharWidth); |
| } |
| |
| Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp)); |
| ++NextFieldOffsetInChars; |
| |
| FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth); |
| } |
| |
| assert(FieldValue.getBitWidth() > 0 && |
| "Should have at least one bit left!"); |
| assert(FieldValue.getBitWidth() <= CharWidth && |
| "Should not have more than a byte left!"); |
| |
| if (FieldValue.getBitWidth() < CharWidth) { |
| if (CGM.getDataLayout().isBigEndian()) { |
| unsigned BitWidth = FieldValue.getBitWidth(); |
| |
| FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth); |
| } else |
| FieldValue = FieldValue.zext(CharWidth); |
| } |
| |
| // Append the last element. |
| Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), |
| FieldValue)); |
| ++NextFieldOffsetInChars; |
| } |
| |
| void ConstStructBuilder::AppendPadding(CharUnits PadSize) { |
| if (PadSize.isZero()) |
| return; |
| |
| llvm::Type *Ty = CGM.Int8Ty; |
| if (PadSize > CharUnits::One()) |
| Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity()); |
| |
| llvm::Constant *C = llvm::UndefValue::get(Ty); |
| Elements.push_back(C); |
| assert(getAlignment(C) == CharUnits::One() && |
| "Padding must have 1 byte alignment!"); |
| |
| NextFieldOffsetInChars += getSizeInChars(C); |
| } |
| |
| void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) { |
| assert(NextFieldOffsetInChars <= RecordSize && |
| "Size mismatch!"); |
| |
| AppendPadding(RecordSize - NextFieldOffsetInChars); |
| } |
| |
| void ConstStructBuilder::ConvertStructToPacked() { |
| SmallVector<llvm::Constant *, 16> PackedElements; |
| CharUnits ElementOffsetInChars = CharUnits::Zero(); |
| |
| for (unsigned i = 0, e = Elements.size(); i != e; ++i) { |
| llvm::Constant *C = Elements[i]; |
| |
| CharUnits ElementAlign = CharUnits::fromQuantity( |
| CGM.getDataLayout().getABITypeAlignment(C->getType())); |
| CharUnits AlignedElementOffsetInChars = |
| ElementOffsetInChars.RoundUpToAlignment(ElementAlign); |
| |
| if (AlignedElementOffsetInChars > ElementOffsetInChars) { |
| // We need some padding. |
| CharUnits NumChars = |
| AlignedElementOffsetInChars - ElementOffsetInChars; |
| |
| llvm::Type *Ty = CGM.Int8Ty; |
| if (NumChars > CharUnits::One()) |
| Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity()); |
| |
| llvm::Constant *Padding = llvm::UndefValue::get(Ty); |
| PackedElements.push_back(Padding); |
| ElementOffsetInChars += getSizeInChars(Padding); |
| } |
| |
| PackedElements.push_back(C); |
| ElementOffsetInChars += getSizeInChars(C); |
| } |
| |
| assert(ElementOffsetInChars == NextFieldOffsetInChars && |
| "Packing the struct changed its size!"); |
| |
| Elements.swap(PackedElements); |
| LLVMStructAlignment = CharUnits::One(); |
| Packed = true; |
| } |
| |
| bool ConstStructBuilder::Build(InitListExpr *ILE) { |
| if (ILE->initializesStdInitializerList()) { |
| //CGM.ErrorUnsupported(ILE, "global std::initializer_list"); |
| return false; |
| } |
| |
| RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl(); |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| |
| unsigned FieldNo = 0; |
| unsigned ElementNo = 0; |
| const FieldDecl *LastFD = 0; |
| bool IsMsStruct = RD->isMsStruct(CGM.getContext()); |
| |
| for (RecordDecl::field_iterator Field = RD->field_begin(), |
| FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { |
| if (IsMsStruct) { |
| // Zero-length bitfields following non-bitfield members are |
| // ignored: |
| if (CGM.getContext().ZeroBitfieldFollowsNonBitfield(*Field, LastFD)) { |
| --FieldNo; |
| continue; |
| } |
| LastFD = *Field; |
| } |
| |
| // If this is a union, skip all the fields that aren't being initialized. |
| if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field) |
| continue; |
| |
| // Don't emit anonymous bitfields, they just affect layout. |
| if (Field->isUnnamedBitfield()) { |
| LastFD = *Field; |
| continue; |
| } |
| |
| // Get the initializer. A struct can include fields without initializers, |
| // we just use explicit null values for them. |
| llvm::Constant *EltInit; |
| if (ElementNo < ILE->getNumInits()) |
| EltInit = CGM.EmitConstantExpr(ILE->getInit(ElementNo++), |
| Field->getType(), CGF); |
| else |
| EltInit = CGM.EmitNullConstant(Field->getType()); |
| |
| if (!EltInit) |
| return false; |
| |
| if (!Field->isBitField()) { |
| // Handle non-bitfield members. |
| AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit); |
| } else { |
| // Otherwise we have a bitfield. |
| AppendBitField(*Field, Layout.getFieldOffset(FieldNo), |
| cast<llvm::ConstantInt>(EltInit)); |
| } |
| } |
| |
| return true; |
| } |
| |
| namespace { |
| struct BaseInfo { |
| BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index) |
| : Decl(Decl), Offset(Offset), Index(Index) { |
| } |
| |
| const CXXRecordDecl *Decl; |
| CharUnits Offset; |
| unsigned Index; |
| |
| bool operator<(const BaseInfo &O) const { return Offset < O.Offset; } |
| }; |
| } |
| |
| void ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD, |
| bool IsPrimaryBase, llvm::Constant *VTable, |
| const CXXRecordDecl *VTableClass, |
| CharUnits Offset) { |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| |
| if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) { |
| // Add a vtable pointer, if we need one and it hasn't already been added. |
| if (CD->isDynamicClass() && !IsPrimaryBase) |
| AppendVTablePointer(BaseSubobject(CD, Offset), VTable, VTableClass); |
| |
| // Accumulate and sort bases, in order to visit them in address order, which |
| // may not be the same as declaration order. |
| SmallVector<BaseInfo, 8> Bases; |
| Bases.reserve(CD->getNumBases()); |
| unsigned BaseNo = 0; |
| for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(), |
| BaseEnd = CD->bases_end(); Base != BaseEnd; ++Base, ++BaseNo) { |
| assert(!Base->isVirtual() && "should not have virtual bases here"); |
| const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl(); |
| CharUnits BaseOffset = Layout.getBaseClassOffset(BD); |
| Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo)); |
| } |
| std::stable_sort(Bases.begin(), Bases.end()); |
| |
| for (unsigned I = 0, N = Bases.size(); I != N; ++I) { |
| BaseInfo &Base = Bases[I]; |
| |
| bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl; |
| Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase, |
| VTable, VTableClass, Offset + Base.Offset); |
| } |
| } |
| |
| unsigned FieldNo = 0; |
| const FieldDecl *LastFD = 0; |
| bool IsMsStruct = RD->isMsStruct(CGM.getContext()); |
| uint64_t OffsetBits = CGM.getContext().toBits(Offset); |
| |
| for (RecordDecl::field_iterator Field = RD->field_begin(), |
| FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { |
| if (IsMsStruct) { |
| // Zero-length bitfields following non-bitfield members are |
| // ignored: |
| if (CGM.getContext().ZeroBitfieldFollowsNonBitfield(*Field, LastFD)) { |
| --FieldNo; |
| continue; |
| } |
| LastFD = *Field; |
| } |
| |
| // If this is a union, skip all the fields that aren't being initialized. |
| if (RD->isUnion() && Val.getUnionField() != *Field) |
| continue; |
| |
| // Don't emit anonymous bitfields, they just affect layout. |
| if (Field->isUnnamedBitfield()) { |
| LastFD = *Field; |
| continue; |
| } |
| |
| // Emit the value of the initializer. |
| const APValue &FieldValue = |
| RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo); |
| llvm::Constant *EltInit = |
| CGM.EmitConstantValueForMemory(FieldValue, Field->getType(), CGF); |
| assert(EltInit && "EmitConstantValue can't fail"); |
| |
| if (!Field->isBitField()) { |
| // Handle non-bitfield members. |
| AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, EltInit); |
| } else { |
| // Otherwise we have a bitfield. |
| AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, |
| cast<llvm::ConstantInt>(EltInit)); |
| } |
| } |
| } |
| |
| llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) { |
| RecordDecl *RD = Ty->getAs<RecordType>()->getDecl(); |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| |
| CharUnits LayoutSizeInChars = Layout.getSize(); |
| |
| if (NextFieldOffsetInChars > LayoutSizeInChars) { |
| // If the struct is bigger than the size of the record type, |
| // we must have a flexible array member at the end. |
| assert(RD->hasFlexibleArrayMember() && |
| "Must have flexible array member if struct is bigger than type!"); |
| |
| // No tail padding is necessary. |
| } else { |
| // Append tail padding if necessary. |
| AppendTailPadding(LayoutSizeInChars); |
| |
| CharUnits LLVMSizeInChars = |
| NextFieldOffsetInChars.RoundUpToAlignment(LLVMStructAlignment); |
| |
| // Check if we need to convert the struct to a packed struct. |
| if (NextFieldOffsetInChars <= LayoutSizeInChars && |
| LLVMSizeInChars > LayoutSizeInChars) { |
| assert(!Packed && "Size mismatch!"); |
| |
| ConvertStructToPacked(); |
| assert(NextFieldOffsetInChars <= LayoutSizeInChars && |
| "Converting to packed did not help!"); |
| } |
| |
| assert(LayoutSizeInChars == NextFieldOffsetInChars && |
| "Tail padding mismatch!"); |
| } |
| |
| // Pick the type to use. If the type is layout identical to the ConvertType |
| // type then use it, otherwise use whatever the builder produced for us. |
| llvm::StructType *STy = |
| llvm::ConstantStruct::getTypeForElements(CGM.getLLVMContext(), |
| Elements, Packed); |
| llvm::Type *ValTy = CGM.getTypes().ConvertType(Ty); |
| if (llvm::StructType *ValSTy = dyn_cast<llvm::StructType>(ValTy)) { |
| if (ValSTy->isLayoutIdentical(STy)) |
| STy = ValSTy; |
| } |
| |
| llvm::Constant *Result = llvm::ConstantStruct::get(STy, Elements); |
| |
| assert(NextFieldOffsetInChars.RoundUpToAlignment(getAlignment(Result)) == |
| getSizeInChars(Result) && "Size mismatch!"); |
| |
| return Result; |
| } |
| |
| llvm::Constant *ConstStructBuilder::BuildStruct(CodeGenModule &CGM, |
| CodeGenFunction *CGF, |
| InitListExpr *ILE) { |
| ConstStructBuilder Builder(CGM, CGF); |
| |
| if (!Builder.Build(ILE)) |
| return 0; |
| |
| return Builder.Finalize(ILE->getType()); |
| } |
| |
| llvm::Constant *ConstStructBuilder::BuildStruct(CodeGenModule &CGM, |
| CodeGenFunction *CGF, |
| const APValue &Val, |
| QualType ValTy) { |
| ConstStructBuilder Builder(CGM, CGF); |
| |
| const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl(); |
| const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD); |
| llvm::Constant *VTable = 0; |
| if (CD && CD->isDynamicClass()) |
| VTable = CGM.getVTables().GetAddrOfVTable(CD); |
| |
| Builder.Build(Val, RD, false, VTable, CD, CharUnits::Zero()); |
| |
| return Builder.Finalize(ValTy); |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // ConstExprEmitter |
| //===----------------------------------------------------------------------===// |
| |
| /// This class only needs to handle two cases: |
| /// 1) Literals (this is used by APValue emission to emit literals). |
| /// 2) Arrays, structs and unions (outside C++11 mode, we don't currently |
| /// constant fold these types). |
| class ConstExprEmitter : |
| public StmtVisitor<ConstExprEmitter, llvm::Constant*> { |
| CodeGenModule &CGM; |
| CodeGenFunction *CGF; |
| llvm::LLVMContext &VMContext; |
| public: |
| ConstExprEmitter(CodeGenModule &cgm, CodeGenFunction *cgf) |
| : CGM(cgm), CGF(cgf), VMContext(cgm.getLLVMContext()) { |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Visitor Methods |
| //===--------------------------------------------------------------------===// |
| |
| llvm::Constant *VisitStmt(Stmt *S) { |
| return 0; |
| } |
| |
| llvm::Constant *VisitParenExpr(ParenExpr *PE) { |
| return Visit(PE->getSubExpr()); |
| } |
| |
| llvm::Constant * |
| VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE) { |
| return Visit(PE->getReplacement()); |
| } |
| |
| llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE) { |
| return Visit(GE->getResultExpr()); |
| } |
| |
| llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { |
| return Visit(E->getInitializer()); |
| } |
| |
| llvm::Constant *VisitCastExpr(CastExpr* E) { |
| Expr *subExpr = E->getSubExpr(); |
| llvm::Constant *C = CGM.EmitConstantExpr(subExpr, subExpr->getType(), CGF); |
| if (!C) return 0; |
| |
| llvm::Type *destType = ConvertType(E->getType()); |
| |
| switch (E->getCastKind()) { |
| case CK_ToUnion: { |
| // GCC cast to union extension |
| assert(E->getType()->isUnionType() && |
| "Destination type is not union type!"); |
| |
| // Build a struct with the union sub-element as the first member, |
| // and padded to the appropriate size |
| SmallVector<llvm::Constant*, 2> Elts; |
| SmallVector<llvm::Type*, 2> Types; |
| Elts.push_back(C); |
| Types.push_back(C->getType()); |
| unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType()); |
| unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destType); |
| |
| assert(CurSize <= TotalSize && "Union size mismatch!"); |
| if (unsigned NumPadBytes = TotalSize - CurSize) { |
| llvm::Type *Ty = CGM.Int8Ty; |
| if (NumPadBytes > 1) |
| Ty = llvm::ArrayType::get(Ty, NumPadBytes); |
| |
| Elts.push_back(llvm::UndefValue::get(Ty)); |
| Types.push_back(Ty); |
| } |
| |
| llvm::StructType* STy = |
| llvm::StructType::get(C->getType()->getContext(), Types, false); |
| return llvm::ConstantStruct::get(STy, Elts); |
| } |
| |
| case CK_LValueToRValue: |
| case CK_AtomicToNonAtomic: |
| case CK_NonAtomicToAtomic: |
| case CK_NoOp: |
| return C; |
| |
| case CK_Dependent: llvm_unreachable("saw dependent cast!"); |
| |
| case CK_BuiltinFnToFnPtr: |
| llvm_unreachable("builtin functions are handled elsewhere"); |
| |
| case CK_ReinterpretMemberPointer: |
| case CK_DerivedToBaseMemberPointer: |
| case CK_BaseToDerivedMemberPointer: |
| return CGM.getCXXABI().EmitMemberPointerConversion(E, C); |
| |
| // These will never be supported. |
| case CK_ObjCObjectLValueCast: |
| case CK_ARCProduceObject: |
| case CK_ARCConsumeObject: |
| case CK_ARCReclaimReturnedObject: |
| case CK_ARCExtendBlockObject: |
| case CK_CopyAndAutoreleaseBlockObject: |
| return 0; |
| |
| // These don't need to be handled here because Evaluate knows how to |
| // evaluate them in the cases where they can be folded. |
| case CK_BitCast: |
| case CK_ToVoid: |
| case CK_Dynamic: |
| case CK_LValueBitCast: |
| case CK_NullToMemberPointer: |
| case CK_UserDefinedConversion: |
| case CK_ConstructorConversion: |
| case CK_CPointerToObjCPointerCast: |
| case CK_BlockPointerToObjCPointerCast: |
| case CK_AnyPointerToBlockPointerCast: |
| case CK_ArrayToPointerDecay: |
| case CK_FunctionToPointerDecay: |
| case CK_BaseToDerived: |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: |
| case CK_MemberPointerToBoolean: |
| case CK_VectorSplat: |
| case CK_FloatingRealToComplex: |
| case CK_FloatingComplexToReal: |
| case CK_FloatingComplexToBoolean: |
| case CK_FloatingComplexCast: |
| case CK_FloatingComplexToIntegralComplex: |
| case CK_IntegralRealToComplex: |
| case CK_IntegralComplexToReal: |
| case CK_IntegralComplexToBoolean: |
| case CK_IntegralComplexCast: |
| case CK_IntegralComplexToFloatingComplex: |
| case CK_PointerToIntegral: |
| case CK_PointerToBoolean: |
| case CK_NullToPointer: |
| case CK_IntegralCast: |
| case CK_IntegralToPointer: |
| case CK_IntegralToBoolean: |
| case CK_IntegralToFloating: |
| case CK_FloatingToIntegral: |
| case CK_FloatingToBoolean: |
| case CK_FloatingCast: |
| case CK_ZeroToOCLEvent: |
| return 0; |
| } |
| llvm_unreachable("Invalid CastKind"); |
| } |
| |
| llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { |
| return Visit(DAE->getExpr()); |
| } |
| |
| llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) { |
| // No need for a DefaultInitExprScope: we don't handle 'this' in a |
| // constant expression. |
| return Visit(DIE->getExpr()); |
| } |
| |
| llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E) { |
| return Visit(E->GetTemporaryExpr()); |
| } |
| |
| llvm::Constant *EmitArrayInitialization(InitListExpr *ILE) { |
| if (ILE->isStringLiteralInit()) |
| return Visit(ILE->getInit(0)); |
| |
| llvm::ArrayType *AType = |
| cast<llvm::ArrayType>(ConvertType(ILE->getType())); |
| llvm::Type *ElemTy = AType->getElementType(); |
| unsigned NumInitElements = ILE->getNumInits(); |
| unsigned NumElements = AType->getNumElements(); |
| |
| // Initialising an array requires us to automatically |
| // initialise any elements that have not been initialised explicitly |
| unsigned NumInitableElts = std::min(NumInitElements, NumElements); |
| |
| // Copy initializer elements. |
| std::vector<llvm::Constant*> Elts; |
| Elts.reserve(NumInitableElts + NumElements); |
| |
| bool RewriteType = false; |
| for (unsigned i = 0; i < NumInitableElts; ++i) { |
| Expr *Init = ILE->getInit(i); |
| llvm::Constant *C = CGM.EmitConstantExpr(Init, Init->getType(), CGF); |
| if (!C) |
| return 0; |
| RewriteType |= (C->getType() != ElemTy); |
| Elts.push_back(C); |
| } |
| |
| // Initialize remaining array elements. |
| // FIXME: This doesn't handle member pointers correctly! |
| llvm::Constant *fillC; |
| if (Expr *filler = ILE->getArrayFiller()) |
| fillC = CGM.EmitConstantExpr(filler, filler->getType(), CGF); |
| else |
| fillC = llvm::Constant::getNullValue(ElemTy); |
| if (!fillC) |
| return 0; |
| RewriteType |= (fillC->getType() != ElemTy); |
| Elts.resize(NumElements, fillC); |
| |
| if (RewriteType) { |
| // FIXME: Try to avoid packing the array |
| std::vector<llvm::Type*> Types; |
| Types.reserve(NumInitableElts + NumElements); |
| for (unsigned i = 0, e = Elts.size(); i < e; ++i) |
| Types.push_back(Elts[i]->getType()); |
| llvm::StructType *SType = llvm::StructType::get(AType->getContext(), |
| Types, true); |
| return llvm::ConstantStruct::get(SType, Elts); |
| } |
| |
| return llvm::ConstantArray::get(AType, Elts); |
| } |
| |
| llvm::Constant *EmitRecordInitialization(InitListExpr *ILE) { |
| return ConstStructBuilder::BuildStruct(CGM, CGF, ILE); |
| } |
| |
| llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E) { |
| return CGM.EmitNullConstant(E->getType()); |
| } |
| |
| llvm::Constant *VisitInitListExpr(InitListExpr *ILE) { |
| if (ILE->getType()->isArrayType()) |
| return EmitArrayInitialization(ILE); |
| |
| if (ILE->getType()->isRecordType()) |
| return EmitRecordInitialization(ILE); |
| |
| return 0; |
| } |
| |
| llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E) { |
| if (!E->getConstructor()->isTrivial()) |
| return 0; |
| |
| QualType Ty = E->getType(); |
| |
| // FIXME: We should not have to call getBaseElementType here. |
| const RecordType *RT = |
| CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>(); |
| const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); |
| |
| // If the class doesn't have a trivial destructor, we can't emit it as a |
| // constant expr. |
| if (!RD->hasTrivialDestructor()) |
| return 0; |
| |
| // Only copy and default constructors can be trivial. |
| |
| |
| if (E->getNumArgs()) { |
| assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument"); |
| assert(E->getConstructor()->isCopyOrMoveConstructor() && |
| "trivial ctor has argument but isn't a copy/move ctor"); |
| |
| Expr *Arg = E->getArg(0); |
| assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) && |
| "argument to copy ctor is of wrong type"); |
| |
| return Visit(Arg); |
| } |
| |
| return CGM.EmitNullConstant(Ty); |
| } |
| |
| llvm::Constant *VisitStringLiteral(StringLiteral *E) { |
| return CGM.GetConstantArrayFromStringLiteral(E); |
| } |
| |
| llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E) { |
| // This must be an @encode initializing an array in a static initializer. |
| // Don't emit it as the address of the string, emit the string data itself |
| // as an inline array. |
| std::string Str; |
| CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str); |
| const ConstantArrayType *CAT = cast<ConstantArrayType>(E->getType()); |
| |
| // Resize the string to the right size, adding zeros at the end, or |
| // truncating as needed. |
| Str.resize(CAT->getSize().getZExtValue(), '\0'); |
| return llvm::ConstantDataArray::getString(VMContext, Str, false); |
| } |
| |
| llvm::Constant *VisitUnaryExtension(const UnaryOperator *E) { |
| return Visit(E->getSubExpr()); |
| } |
| |
| // Utility methods |
| llvm::Type *ConvertType(QualType T) { |
| return CGM.getTypes().ConvertType(T); |
| } |
| |
| public: |
| llvm::Constant *EmitLValue(APValue::LValueBase LVBase) { |
| if (const ValueDecl *Decl = LVBase.dyn_cast<const ValueDecl*>()) { |
| if (Decl->hasAttr<WeakRefAttr>()) |
| return CGM.GetWeakRefReference(Decl); |
| if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Decl)) |
| return CGM.GetAddrOfFunction(FD); |
| if (const VarDecl* VD = dyn_cast<VarDecl>(Decl)) { |
| // We can never refer to a variable with local storage. |
| if (!VD->hasLocalStorage()) { |
| if (VD->isFileVarDecl() || VD->hasExternalStorage()) |
| return CGM.GetAddrOfGlobalVar(VD); |
| else if (VD->isLocalVarDecl()) |
| return CGM.getStaticLocalDeclAddress(VD); |
| } |
| } |
| return 0; |
| } |
| |
| Expr *E = const_cast<Expr*>(LVBase.get<const Expr*>()); |
| switch (E->getStmtClass()) { |
| default: break; |
| case Expr::CompoundLiteralExprClass: { |
| // Note that due to the nature of compound literals, this is guaranteed |
| // to be the only use of the variable, so we just generate it here. |
| CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E); |
| llvm::Constant* C = CGM.EmitConstantExpr(CLE->getInitializer(), |
| CLE->getType(), CGF); |
| // FIXME: "Leaked" on failure. |
| if (C) |
| C = new llvm::GlobalVariable(CGM.getModule(), C->getType(), |
| E->getType().isConstant(CGM.getContext()), |
| llvm::GlobalValue::InternalLinkage, |
| C, ".compoundliteral", 0, |
| llvm::GlobalVariable::NotThreadLocal, |
| CGM.getContext().getTargetAddressSpace(E->getType())); |
| return C; |
| } |
| case Expr::StringLiteralClass: |
| return CGM.GetAddrOfConstantStringFromLiteral(cast<StringLiteral>(E)); |
| case Expr::ObjCEncodeExprClass: |
| return CGM.GetAddrOfConstantStringFromObjCEncode(cast<ObjCEncodeExpr>(E)); |
| case Expr::ObjCStringLiteralClass: { |
| ObjCStringLiteral* SL = cast<ObjCStringLiteral>(E); |
| llvm::Constant *C = |
| CGM.getObjCRuntime().GenerateConstantString(SL->getString()); |
| return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType())); |
| } |
| case Expr::PredefinedExprClass: { |
| unsigned Type = cast<PredefinedExpr>(E)->getIdentType(); |
| if (CGF) { |
| LValue Res = CGF->EmitPredefinedLValue(cast<PredefinedExpr>(E)); |
| return cast<llvm::Constant>(Res.getAddress()); |
| } else if (Type == PredefinedExpr::PrettyFunction) { |
| return CGM.GetAddrOfConstantCString("top level", ".tmp"); |
| } |
| |
| return CGM.GetAddrOfConstantCString("", ".tmp"); |
| } |
| case Expr::AddrLabelExprClass: { |
| assert(CGF && "Invalid address of label expression outside function."); |
| llvm::Constant *Ptr = |
| CGF->GetAddrOfLabel(cast<AddrLabelExpr>(E)->getLabel()); |
| return llvm::ConstantExpr::getBitCast(Ptr, ConvertType(E->getType())); |
| } |
| case Expr::CallExprClass: { |
| CallExpr* CE = cast<CallExpr>(E); |
| unsigned builtin = CE->isBuiltinCall(); |
| if (builtin != |
| Builtin::BI__builtin___CFStringMakeConstantString && |
| builtin != |
| Builtin::BI__builtin___NSStringMakeConstantString) |
| break; |
| const Expr *Arg = CE->getArg(0)->IgnoreParenCasts(); |
| const StringLiteral *Literal = cast<StringLiteral>(Arg); |
| if (builtin == |
| Builtin::BI__builtin___NSStringMakeConstantString) { |
| return CGM.getObjCRuntime().GenerateConstantString(Literal); |
| } |
| // FIXME: need to deal with UCN conversion issues. |
| return CGM.GetAddrOfConstantCFString(Literal); |
| } |
| case Expr::BlockExprClass: { |
| std::string FunctionName; |
| if (CGF) |
| FunctionName = CGF->CurFn->getName(); |
| else |
| FunctionName = "global"; |
| |
| return CGM.GetAddrOfGlobalBlock(cast<BlockExpr>(E), FunctionName.c_str()); |
| } |
| case Expr::CXXTypeidExprClass: { |
| CXXTypeidExpr *Typeid = cast<CXXTypeidExpr>(E); |
| QualType T; |
| if (Typeid->isTypeOperand()) |
| T = Typeid->getTypeOperand(); |
| else |
| T = Typeid->getExprOperand()->getType(); |
| return CGM.GetAddrOfRTTIDescriptor(T); |
| } |
| case Expr::CXXUuidofExprClass: { |
| return CGM.GetAddrOfUuidDescriptor(cast<CXXUuidofExpr>(E)); |
| } |
| } |
| |
| return 0; |
| } |
| }; |
| |
| } // end anonymous namespace. |
| |
| llvm::Constant *CodeGenModule::EmitConstantInit(const VarDecl &D, |
| CodeGenFunction *CGF) { |
| // Make a quick check if variable can be default NULL initialized |
| // and avoid going through rest of code which may do, for c++11, |
| // initialization of memory to all NULLs. |
| if (!D.hasLocalStorage()) { |
| QualType Ty = D.getType(); |
| if (Ty->isArrayType()) |
| Ty = Context.getBaseElementType(Ty); |
| if (Ty->isRecordType()) |
| if (const CXXConstructExpr *E = |
| dyn_cast_or_null<CXXConstructExpr>(D.getInit())) { |
| const CXXConstructorDecl *CD = E->getConstructor(); |
| if (CD->isTrivial() && CD->isDefaultConstructor()) |
| return EmitNullConstant(D.getType()); |
| } |
| } |
| |
| if (const APValue *Value = D.evaluateValue()) |
| return EmitConstantValueForMemory(*Value, D.getType(), CGF); |
| |
| // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a |
| // reference is a constant expression, and the reference binds to a temporary, |
| // then constant initialization is performed. ConstExprEmitter will |
| // incorrectly emit a prvalue constant in this case, and the calling code |
| // interprets that as the (pointer) value of the reference, rather than the |
| // desired value of the referee. |
| if (D.getType()->isReferenceType()) |
| return 0; |
| |
| const Expr *E = D.getInit(); |
| assert(E && "No initializer to emit"); |
| |
| llvm::Constant* C = ConstExprEmitter(*this, CGF).Visit(const_cast<Expr*>(E)); |
| if (C && C->getType()->isIntegerTy(1)) { |
| llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType()); |
| C = llvm::ConstantExpr::getZExt(C, BoolTy); |
| } |
| return C; |
| } |
| |
| llvm::Constant *CodeGenModule::EmitConstantExpr(const Expr *E, |
| QualType DestType, |
| CodeGenFunction *CGF) { |
| Expr::EvalResult Result; |
| |
| bool Success = false; |
| |
| if (DestType->isReferenceType()) |
| Success = E->EvaluateAsLValue(Result, Context); |
| else |
| Success = E->EvaluateAsRValue(Result, Context); |
| |
| llvm::Constant *C = 0; |
| if (Success && !Result.HasSideEffects) |
| C = EmitConstantValue(Result.Val, DestType, CGF); |
| else |
| C = ConstExprEmitter(*this, CGF).Visit(const_cast<Expr*>(E)); |
| |
| if (C && C->getType()->isIntegerTy(1)) { |
| llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType()); |
| C = llvm::ConstantExpr::getZExt(C, BoolTy); |
| } |
| return C; |
| } |
| |
| llvm::Constant *CodeGenModule::EmitConstantValue(const APValue &Value, |
| QualType DestType, |
| CodeGenFunction *CGF) { |
| switch (Value.getKind()) { |
| case APValue::Uninitialized: |
| llvm_unreachable("Constant expressions should be initialized."); |
| case APValue::LValue: { |
| llvm::Type *DestTy = getTypes().ConvertTypeForMem(DestType); |
| llvm::Constant *Offset = |
| llvm::ConstantInt::get(Int64Ty, Value.getLValueOffset().getQuantity()); |
| |
| llvm::Constant *C; |
| if (APValue::LValueBase LVBase = Value.getLValueBase()) { |
| // An array can be represented as an lvalue referring to the base. |
| if (isa<llvm::ArrayType>(DestTy)) { |
| assert(Offset->isNullValue() && "offset on array initializer"); |
| return ConstExprEmitter(*this, CGF).Visit( |
| const_cast<Expr*>(LVBase.get<const Expr*>())); |
| } |
| |
| C = ConstExprEmitter(*this, CGF).EmitLValue(LVBase); |
| |
| // Apply offset if necessary. |
| if (!Offset->isNullValue()) { |
| llvm::Constant *Casted = llvm::ConstantExpr::getBitCast(C, Int8PtrTy); |
| Casted = llvm::ConstantExpr::getGetElementPtr(Casted, Offset); |
| C = llvm::ConstantExpr::getBitCast(Casted, C->getType()); |
| } |
| |
| // Convert to the appropriate type; this could be an lvalue for |
| // an integer. |
| if (isa<llvm::PointerType>(DestTy)) |
| return llvm::ConstantExpr::getBitCast(C, DestTy); |
| |
| return llvm::ConstantExpr::getPtrToInt(C, DestTy); |
| } else { |
| C = Offset; |
| |
| // Convert to the appropriate type; this could be an lvalue for |
| // an integer. |
| if (isa<llvm::PointerType>(DestTy)) |
| return llvm::ConstantExpr::getIntToPtr(C, DestTy); |
| |
| // If the types don't match this should only be a truncate. |
| if (C->getType() != DestTy) |
| return llvm::ConstantExpr::getTrunc(C, DestTy); |
| |
| return C; |
| } |
| } |
| case APValue::Int: |
| return llvm::ConstantInt::get(VMContext, Value.getInt()); |
| case APValue::ComplexInt: { |
| llvm::Constant *Complex[2]; |
| |
| Complex[0] = llvm::ConstantInt::get(VMContext, |
| Value.getComplexIntReal()); |
| Complex[1] = llvm::ConstantInt::get(VMContext, |
| Value.getComplexIntImag()); |
| |
| // FIXME: the target may want to specify that this is packed. |
| llvm::StructType *STy = llvm::StructType::get(Complex[0]->getType(), |
| Complex[1]->getType(), |
| NULL); |
| return llvm::ConstantStruct::get(STy, Complex); |
| } |
| case APValue::Float: { |
| const llvm::APFloat &Init = Value.getFloat(); |
| if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf && |
| !Context.getLangOpts().NativeHalfType) |
| return llvm::ConstantInt::get(VMContext, Init.bitcastToAPInt()); |
| else |
| return llvm::ConstantFP::get(VMContext, Init); |
| } |
| case APValue::ComplexFloat: { |
| llvm::Constant *Complex[2]; |
| |
| Complex[0] = llvm::ConstantFP::get(VMContext, |
| Value.getComplexFloatReal()); |
| Complex[1] = llvm::ConstantFP::get(VMContext, |
| Value.getComplexFloatImag()); |
| |
| // FIXME: the target may want to specify that this is packed. |
| llvm::StructType *STy = llvm::StructType::get(Complex[0]->getType(), |
| Complex[1]->getType(), |
| NULL); |
| return llvm::ConstantStruct::get(STy, Complex); |
| } |
| case APValue::Vector: { |
| SmallVector<llvm::Constant *, 4> Inits; |
| unsigned NumElts = Value.getVectorLength(); |
| |
| for (unsigned i = 0; i != NumElts; ++i) { |
| const APValue &Elt = Value.getVectorElt(i); |
| if (Elt.isInt()) |
| Inits.push_back(llvm::ConstantInt::get(VMContext, Elt.getInt())); |
| else |
| Inits.push_back(llvm::ConstantFP::get(VMContext, Elt.getFloat())); |
| } |
| return llvm::ConstantVector::get(Inits); |
| } |
| case APValue::AddrLabelDiff: { |
| const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS(); |
| const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS(); |
| llvm::Constant *LHS = EmitConstantExpr(LHSExpr, LHSExpr->getType(), CGF); |
| llvm::Constant *RHS = EmitConstantExpr(RHSExpr, RHSExpr->getType(), CGF); |
| |
| // Compute difference |
| llvm::Type *ResultType = getTypes().ConvertType(DestType); |
| LHS = llvm::ConstantExpr::getPtrToInt(LHS, IntPtrTy); |
| RHS = llvm::ConstantExpr::getPtrToInt(RHS, IntPtrTy); |
| llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS); |
| |
| // LLVM is a bit sensitive about the exact format of the |
| // address-of-label difference; make sure to truncate after |
| // the subtraction. |
| return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType); |
| } |
| case APValue::Struct: |
| case APValue::Union: |
| return ConstStructBuilder::BuildStruct(*this, CGF, Value, DestType); |
| case APValue::Array: { |
| const ArrayType *CAT = Context.getAsArrayType(DestType); |
| unsigned NumElements = Value.getArraySize(); |
| unsigned NumInitElts = Value.getArrayInitializedElts(); |
| |
| std::vector<llvm::Constant*> Elts; |
| Elts.reserve(NumElements); |
| |
| // Emit array filler, if there is one. |
| llvm::Constant *Filler = 0; |
| if (Value.hasArrayFiller()) |
| Filler = EmitConstantValueForMemory(Value.getArrayFiller(), |
| CAT->getElementType(), CGF); |
| |
| // Emit initializer elements. |
| llvm::Type *CommonElementType = 0; |
| for (unsigned I = 0; I < NumElements; ++I) { |
| llvm::Constant *C = Filler; |
| if (I < NumInitElts) |
| C = EmitConstantValueForMemory(Value.getArrayInitializedElt(I), |
| CAT->getElementType(), CGF); |
| else |
| assert(Filler && "Missing filler for implicit elements of initializer"); |
| if (I == 0) |
| CommonElementType = C->getType(); |
| else if (C->getType() != CommonElementType) |
| CommonElementType = 0; |
| Elts.push_back(C); |
| } |
| |
| if (!CommonElementType) { |
| // FIXME: Try to avoid packing the array |
| std::vector<llvm::Type*> Types; |
| Types.reserve(NumElements); |
| for (unsigned i = 0, e = Elts.size(); i < e; ++i) |
| Types.push_back(Elts[i]->getType()); |
| llvm::StructType *SType = llvm::StructType::get(VMContext, Types, true); |
| return llvm::ConstantStruct::get(SType, Elts); |
| } |
| |
| llvm::ArrayType *AType = |
| llvm::ArrayType::get(CommonElementType, NumElements); |
| return llvm::ConstantArray::get(AType, Elts); |
| } |
| case APValue::MemberPointer: |
| return getCXXABI().EmitMemberPointer(Value, DestType); |
| } |
| llvm_unreachable("Unknown APValue kind"); |
| } |
| |
| llvm::Constant * |
| CodeGenModule::EmitConstantValueForMemory(const APValue &Value, |
| QualType DestType, |
| CodeGenFunction *CGF) { |
| llvm::Constant *C = EmitConstantValue(Value, DestType, CGF); |
| if (C->getType()->isIntegerTy(1)) { |
| llvm::Type *BoolTy = getTypes().ConvertTypeForMem(DestType); |
| C = llvm::ConstantExpr::getZExt(C, BoolTy); |
| } |
| return C; |
| } |
| |
| llvm::Constant * |
| CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) { |
| assert(E->isFileScope() && "not a file-scope compound literal expr"); |
| return ConstExprEmitter(*this, 0).EmitLValue(E); |
| } |
| |
| llvm::Constant * |
| CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) { |
| // Member pointer constants always have a very particular form. |
| const MemberPointerType *type = cast<MemberPointerType>(uo->getType()); |
| const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl(); |
| |
| // A member function pointer. |
| if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl)) |
| return getCXXABI().EmitMemberPointer(method); |
| |
| // Otherwise, a member data pointer. |
| uint64_t fieldOffset = getContext().getFieldOffset(decl); |
| CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset); |
| return getCXXABI().EmitMemberDataPointer(type, chars); |
| } |
| |
| static void |
| FillInNullDataMemberPointers(CodeGenModule &CGM, QualType T, |
| SmallVectorImpl<llvm::Constant *> &Elements, |
| uint64_t StartOffset) { |
| assert(StartOffset % CGM.getContext().getCharWidth() == 0 && |
| "StartOffset not byte aligned!"); |
| |
| if (CGM.getTypes().isZeroInitializable(T)) |
| return; |
| |
| if (const ConstantArrayType *CAT = |
| CGM.getContext().getAsConstantArrayType(T)) { |
| QualType ElementTy = CAT->getElementType(); |
| uint64_t ElementSize = CGM.getContext().getTypeSize(ElementTy); |
| |
| for (uint64_t I = 0, E = CAT->getSize().getZExtValue(); I != E; ++I) { |
| FillInNullDataMemberPointers(CGM, ElementTy, Elements, |
| StartOffset + I * ElementSize); |
| } |
| } else if (const RecordType *RT = T->getAs<RecordType>()) { |
| const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| |
| // Go through all bases and fill in any null pointer to data members. |
| for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), |
| E = RD->bases_end(); I != E; ++I) { |
| if (I->isVirtual()) { |
| // Ignore virtual bases. |
| continue; |
| } |
| |
| const CXXRecordDecl *BaseDecl = |
| cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); |
| |
| // Ignore empty bases. |
| if (BaseDecl->isEmpty()) |
| continue; |
| |
| // Ignore bases that don't have any pointer to data members. |
| if (CGM.getTypes().isZeroInitializable(BaseDecl)) |
| continue; |
| |
| uint64_t BaseOffset = |
| CGM.getContext().toBits(Layout.getBaseClassOffset(BaseDecl)); |
| FillInNullDataMemberPointers(CGM, I->getType(), |
| Elements, StartOffset + BaseOffset); |
| } |
| |
| // Visit all fields. |
| unsigned FieldNo = 0; |
| for (RecordDecl::field_iterator I = RD->field_begin(), |
| E = RD->field_end(); I != E; ++I, ++FieldNo) { |
| QualType FieldType = I->getType(); |
| |
| if (CGM.getTypes().isZeroInitializable(FieldType)) |
| continue; |
| |
| uint64_t FieldOffset = StartOffset + Layout.getFieldOffset(FieldNo); |
| FillInNullDataMemberPointers(CGM, FieldType, Elements, FieldOffset); |
| } |
| } else { |
| assert(T->isMemberPointerType() && "Should only see member pointers here!"); |
| assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() && |
| "Should only see pointers to data members here!"); |
| |
| CharUnits StartIndex = CGM.getContext().toCharUnitsFromBits(StartOffset); |
| CharUnits EndIndex = StartIndex + CGM.getContext().getTypeSizeInChars(T); |
| |
| // FIXME: hardcodes Itanium member pointer representation! |
| llvm::Constant *NegativeOne = |
| llvm::ConstantInt::get(CGM.Int8Ty, -1ULL, /*isSigned*/true); |
| |
| // Fill in the null data member pointer. |
| for (CharUnits I = StartIndex; I != EndIndex; ++I) |
| Elements[I.getQuantity()] = NegativeOne; |
| } |
| } |
| |
| static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM, |
| llvm::Type *baseType, |
| const CXXRecordDecl *base); |
| |
| static llvm::Constant *EmitNullConstant(CodeGenModule &CGM, |
| const CXXRecordDecl *record, |
| bool asCompleteObject) { |
| const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record); |
| llvm::StructType *structure = |
| (asCompleteObject ? layout.getLLVMType() |
| : layout.getBaseSubobjectLLVMType()); |
| |
| unsigned numElements = structure->getNumElements(); |
| std::vector<llvm::Constant *> elements(numElements); |
| |
| // Fill in all the bases. |
| for (CXXRecordDecl::base_class_const_iterator |
| I = record->bases_begin(), E = record->bases_end(); I != E; ++I) { |
| if (I->isVirtual()) { |
| // Ignore virtual bases; if we're laying out for a complete |
| // object, we'll lay these out later. |
| continue; |
| } |
| |
| const CXXRecordDecl *base = |
| cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl()); |
| |
| // Ignore empty bases. |
| if (base->isEmpty()) |
| continue; |
| |
| unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base); |
| llvm::Type *baseType = structure->getElementType(fieldIndex); |
| elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base); |
| } |
| |
| // Fill in all the fields. |
| for (RecordDecl::field_iterator I = record->field_begin(), |
| E = record->field_end(); I != E; ++I) { |
| const FieldDecl *field = *I; |
| |
| // Fill in non-bitfields. (Bitfields always use a zero pattern, which we |
| // will fill in later.) |
| if (!field->isBitField()) { |
| unsigned fieldIndex = layout.getLLVMFieldNo(field); |
| elements[fieldIndex] = CGM.EmitNullConstant(field->getType()); |
| } |
| |
| // For unions, stop after the first named field. |
| if (record->isUnion() && field->getDeclName()) |
| break; |
| } |
| |
| // Fill in the virtual bases, if we're working with the complete object. |
| if (asCompleteObject) { |
| for (CXXRecordDecl::base_class_const_iterator |
| I = record->vbases_begin(), E = record->vbases_end(); I != E; ++I) { |
| const CXXRecordDecl *base = |
| cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl()); |
| |
| // Ignore empty bases. |
| if (base->isEmpty()) |
| continue; |
| |
| unsigned fieldIndex = layout.getVirtualBaseIndex(base); |
| |
| // We might have already laid this field out. |
| if (elements[fieldIndex]) continue; |
| |
| llvm::Type *baseType = structure->getElementType(fieldIndex); |
| elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base); |
| } |
| } |
| |
| // Now go through all other fields and zero them out. |
| for (unsigned i = 0; i != numElements; ++i) { |
| if (!elements[i]) |
| elements[i] = llvm::Constant::getNullValue(structure->getElementType(i)); |
| } |
| |
| return llvm::ConstantStruct::get(structure, elements); |
| } |
| |
| /// Emit the null constant for a base subobject. |
| static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM, |
| llvm::Type *baseType, |
| const CXXRecordDecl *base) { |
| const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base); |
| |
| // Just zero out bases that don't have any pointer to data members. |
| if (baseLayout.isZeroInitializableAsBase()) |
| return llvm::Constant::getNullValue(baseType); |
| |
| // If the base type is a struct, we can just use its null constant. |
| if (isa<llvm::StructType>(baseType)) { |
| return EmitNullConstant(CGM, base, /*complete*/ false); |
| } |
| |
| // Otherwise, some bases are represented as arrays of i8 if the size |
| // of the base is smaller than its corresponding LLVM type. Figure |
| // out how many elements this base array has. |
| llvm::ArrayType *baseArrayType = cast<llvm::ArrayType>(baseType); |
| unsigned numBaseElements = baseArrayType->getNumElements(); |
| |
| // Fill in null data member pointers. |
| SmallVector<llvm::Constant *, 16> baseElements(numBaseElements); |
| FillInNullDataMemberPointers(CGM, CGM.getContext().getTypeDeclType(base), |
| baseElements, 0); |
| |
| // Now go through all other elements and zero them out. |
| if (numBaseElements) { |
| llvm::Constant *i8_zero = llvm::Constant::getNullValue(CGM.Int8Ty); |
| for (unsigned i = 0; i != numBaseElements; ++i) { |
| if (!baseElements[i]) |
| baseElements[i] = i8_zero; |
| } |
| } |
| |
| return llvm::ConstantArray::get(baseArrayType, baseElements); |
| } |
| |
| llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) { |
| if (getTypes().isZeroInitializable(T)) |
| return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T)); |
| |
| if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) { |
| llvm::ArrayType *ATy = |
| cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T)); |
| |
| QualType ElementTy = CAT->getElementType(); |
| |
| llvm::Constant *Element = EmitNullConstant(ElementTy); |
| unsigned NumElements = CAT->getSize().getZExtValue(); |
| |
| if (Element->isNullValue()) |
| return llvm::ConstantAggregateZero::get(ATy); |
| |
| SmallVector<llvm::Constant *, 8> Array(NumElements, Element); |
| return llvm::ConstantArray::get(ATy, Array); |
| } |
| |
| if (const RecordType *RT = T->getAs<RecordType>()) { |
| const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); |
| return ::EmitNullConstant(*this, RD, /*complete object*/ true); |
| } |
| |
| assert(T->isMemberPointerType() && "Should only see member pointers here!"); |
| assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() && |
| "Should only see pointers to data members here!"); |
| |
| // Itanium C++ ABI 2.3: |
| // A NULL pointer is represented as -1. |
| return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>()); |
| } |
| |
| llvm::Constant * |
| CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) { |
| return ::EmitNullConstant(*this, Record, false); |
| } |
