| //===--- 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 "CodeGenModule.h" |
| #include "CGObjCRuntime.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/Constants.h" |
| #include "llvm/Function.h" |
| #include "llvm/GlobalVariable.h" |
| #include "llvm/Target/TargetData.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| namespace { |
| class ConstStructBuilder { |
| CodeGenModule &CGM; |
| CodeGenFunction *CGF; |
| |
| bool Packed; |
| |
| unsigned NextFieldOffsetInBytes; |
| |
| unsigned LLVMStructAlignment; |
| |
| std::vector<llvm::Constant *> Elements; |
| |
| ConstStructBuilder(CodeGenModule &CGM, CodeGenFunction *CGF) |
| : CGM(CGM), CGF(CGF), Packed(false), NextFieldOffsetInBytes(0), |
| LLVMStructAlignment(1) { } |
| |
| bool AppendField(const FieldDecl *Field, uint64_t FieldOffset, |
| const Expr *InitExpr) { |
| uint64_t FieldOffsetInBytes = FieldOffset / 8; |
| |
| assert(NextFieldOffsetInBytes <= FieldOffsetInBytes |
| && "Field offset mismatch!"); |
| |
| // Emit the field. |
| llvm::Constant *C = CGM.EmitConstantExpr(InitExpr, Field->getType(), CGF); |
| if (!C) |
| return false; |
| |
| unsigned FieldAlignment = getAlignment(C); |
| |
| // Round up the field offset to the alignment of the field type. |
| uint64_t AlignedNextFieldOffsetInBytes = |
| llvm::RoundUpToAlignment(NextFieldOffsetInBytes, FieldAlignment); |
| |
| if (AlignedNextFieldOffsetInBytes > FieldOffsetInBytes) { |
| assert(!Packed && "Alignment is wrong even with a packed struct!"); |
| |
| // Convert the struct to a packed struct. |
| ConvertStructToPacked(); |
| |
| AlignedNextFieldOffsetInBytes = NextFieldOffsetInBytes; |
| } |
| |
| if (AlignedNextFieldOffsetInBytes < FieldOffsetInBytes) { |
| // We need to append padding. |
| AppendPadding(FieldOffsetInBytes - NextFieldOffsetInBytes); |
| |
| assert(NextFieldOffsetInBytes == FieldOffsetInBytes && |
| "Did not add enough padding!"); |
| |
| AlignedNextFieldOffsetInBytes = NextFieldOffsetInBytes; |
| } |
| |
| // Add the field. |
| Elements.push_back(C); |
| NextFieldOffsetInBytes = AlignedNextFieldOffsetInBytes + getSizeInBytes(C); |
| |
| if (Packed) |
| assert(LLVMStructAlignment == 1 && "Packed struct not byte-aligned!"); |
| else |
| LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment); |
| |
| return true; |
| } |
| |
| bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset, |
| const Expr *InitExpr) { |
| llvm::ConstantInt *CI = |
| cast_or_null<llvm::ConstantInt>(CGM.EmitConstantExpr(InitExpr, |
| Field->getType(), |
| CGF)); |
| // FIXME: Can this ever happen? |
| if (!CI) |
| return false; |
| |
| if (FieldOffset > NextFieldOffsetInBytes * 8) { |
| // We need to add padding. |
| uint64_t NumBytes = |
| llvm::RoundUpToAlignment(FieldOffset - |
| NextFieldOffsetInBytes * 8, 8) / 8; |
| |
| AppendPadding(NumBytes); |
| } |
| |
| uint64_t FieldSize = |
| Field->getBitWidth()->EvaluateAsInt(CGM.getContext()).getZExtValue(); |
| |
| 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.zext(FieldSize); |
| |
| // Truncate the size of FieldValue to the bit field size. |
| if (FieldSize < FieldValue.getBitWidth()) |
| FieldValue.trunc(FieldSize); |
| |
| if (FieldOffset < NextFieldOffsetInBytes * 8) { |
| // 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 = |
| NextFieldOffsetInBytes * 8 - FieldOffset; |
| |
| bool FitsCompletelyInPreviousByte = |
| BitsInPreviousByte >= FieldValue.getBitWidth(); |
| |
| llvm::APInt Tmp = FieldValue; |
| |
| if (!FitsCompletelyInPreviousByte) { |
| unsigned NewFieldWidth = FieldSize - BitsInPreviousByte; |
| |
| if (CGM.getTargetData().isBigEndian()) { |
| Tmp = Tmp.lshr(NewFieldWidth); |
| Tmp.trunc(BitsInPreviousByte); |
| |
| // We want the remaining high bits. |
| FieldValue.trunc(NewFieldWidth); |
| } else { |
| Tmp.trunc(BitsInPreviousByte); |
| |
| // We want the remaining low bits. |
| FieldValue = FieldValue.lshr(BitsInPreviousByte); |
| FieldValue.trunc(NewFieldWidth); |
| } |
| } |
| |
| Tmp.zext(8); |
| if (CGM.getTargetData().isBigEndian()) { |
| if (FitsCompletelyInPreviousByte) |
| Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth()); |
| } else { |
| Tmp = Tmp.shl(8 - BitsInPreviousByte); |
| } |
| |
| // Or in the bits that go into the previous byte. |
| if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(Elements.back())) |
| Tmp |= Val->getValue(); |
| else |
| assert(isa<llvm::UndefValue>(Elements.back())); |
| |
| Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp); |
| |
| if (FitsCompletelyInPreviousByte) |
| return true; |
| } |
| |
| while (FieldValue.getBitWidth() > 8) { |
| llvm::APInt Tmp; |
| |
| if (CGM.getTargetData().isBigEndian()) { |
| // We want the high bits. |
| Tmp = FieldValue; |
| Tmp = Tmp.lshr(Tmp.getBitWidth() - 8); |
| Tmp.trunc(8); |
| } else { |
| // We want the low bits. |
| Tmp = FieldValue; |
| Tmp.trunc(8); |
| |
| FieldValue = FieldValue.lshr(8); |
| } |
| |
| Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp)); |
| NextFieldOffsetInBytes++; |
| |
| FieldValue.trunc(FieldValue.getBitWidth() - 8); |
| } |
| |
| assert(FieldValue.getBitWidth() > 0 && |
| "Should have at least one bit left!"); |
| assert(FieldValue.getBitWidth() <= 8 && |
| "Should not have more than a byte left!"); |
| |
| if (FieldValue.getBitWidth() < 8) { |
| if (CGM.getTargetData().isBigEndian()) { |
| unsigned BitWidth = FieldValue.getBitWidth(); |
| |
| FieldValue.zext(8); |
| FieldValue = FieldValue << (8 - BitWidth); |
| } else |
| FieldValue.zext(8); |
| } |
| |
| // Append the last element. |
| Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), |
| FieldValue)); |
| NextFieldOffsetInBytes++; |
| return true; |
| } |
| |
| void AppendPadding(uint64_t NumBytes) { |
| if (!NumBytes) |
| return; |
| |
| const llvm::Type *Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext()); |
| if (NumBytes > 1) |
| Ty = llvm::ArrayType::get(Ty, NumBytes); |
| |
| llvm::Constant *C = llvm::UndefValue::get(Ty); |
| Elements.push_back(C); |
| assert(getAlignment(C) == 1 && "Padding must have 1 byte alignment!"); |
| |
| NextFieldOffsetInBytes += getSizeInBytes(C); |
| } |
| |
| void AppendTailPadding(uint64_t RecordSize) { |
| assert(RecordSize % 8 == 0 && "Invalid record size!"); |
| |
| uint64_t RecordSizeInBytes = RecordSize / 8; |
| assert(NextFieldOffsetInBytes <= RecordSizeInBytes && "Size mismatch!"); |
| |
| unsigned NumPadBytes = RecordSizeInBytes - NextFieldOffsetInBytes; |
| AppendPadding(NumPadBytes); |
| } |
| |
| void ConvertStructToPacked() { |
| std::vector<llvm::Constant *> PackedElements; |
| uint64_t ElementOffsetInBytes = 0; |
| |
| for (unsigned i = 0, e = Elements.size(); i != e; ++i) { |
| llvm::Constant *C = Elements[i]; |
| |
| unsigned ElementAlign = |
| CGM.getTargetData().getABITypeAlignment(C->getType()); |
| uint64_t AlignedElementOffsetInBytes = |
| llvm::RoundUpToAlignment(ElementOffsetInBytes, ElementAlign); |
| |
| if (AlignedElementOffsetInBytes > ElementOffsetInBytes) { |
| // We need some padding. |
| uint64_t NumBytes = |
| AlignedElementOffsetInBytes - ElementOffsetInBytes; |
| |
| const llvm::Type *Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext()); |
| if (NumBytes > 1) |
| Ty = llvm::ArrayType::get(Ty, NumBytes); |
| |
| llvm::Constant *Padding = llvm::UndefValue::get(Ty); |
| PackedElements.push_back(Padding); |
| ElementOffsetInBytes += getSizeInBytes(Padding); |
| } |
| |
| PackedElements.push_back(C); |
| ElementOffsetInBytes += getSizeInBytes(C); |
| } |
| |
| assert(ElementOffsetInBytes == NextFieldOffsetInBytes && |
| "Packing the struct changed its size!"); |
| |
| Elements = PackedElements; |
| LLVMStructAlignment = 1; |
| Packed = true; |
| } |
| |
| bool Build(InitListExpr *ILE) { |
| RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl(); |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| |
| unsigned FieldNo = 0; |
| unsigned ElementNo = 0; |
| for (RecordDecl::field_iterator Field = RD->field_begin(), |
| FieldEnd = RD->field_end(); |
| ElementNo < ILE->getNumInits() && Field != FieldEnd; |
| ++Field, ++FieldNo) { |
| if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field) |
| continue; |
| |
| if (Field->isBitField()) { |
| if (!Field->getIdentifier()) |
| continue; |
| |
| if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo), |
| ILE->getInit(ElementNo))) |
| return false; |
| } else { |
| if (!AppendField(*Field, Layout.getFieldOffset(FieldNo), |
| ILE->getInit(ElementNo))) |
| return false; |
| } |
| |
| ElementNo++; |
| } |
| |
| uint64_t LayoutSizeInBytes = Layout.getSize() / 8; |
| |
| if (NextFieldOffsetInBytes > LayoutSizeInBytes) { |
| // 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. |
| return true; |
| } |
| |
| uint64_t LLVMSizeInBytes = llvm::RoundUpToAlignment(NextFieldOffsetInBytes, |
| LLVMStructAlignment); |
| |
| // Check if we need to convert the struct to a packed struct. |
| if (NextFieldOffsetInBytes <= LayoutSizeInBytes && |
| LLVMSizeInBytes > LayoutSizeInBytes) { |
| assert(!Packed && "Size mismatch!"); |
| |
| ConvertStructToPacked(); |
| assert(NextFieldOffsetInBytes == LayoutSizeInBytes && |
| "Converting to packed did not help!"); |
| } |
| |
| // Append tail padding if necessary. |
| AppendTailPadding(Layout.getSize()); |
| |
| assert(Layout.getSize() / 8 == NextFieldOffsetInBytes && |
| "Tail padding mismatch!"); |
| |
| return true; |
| } |
| |
| unsigned getAlignment(const llvm::Constant *C) const { |
| if (Packed) |
| return 1; |
| |
| return CGM.getTargetData().getABITypeAlignment(C->getType()); |
| } |
| |
| uint64_t getSizeInBytes(const llvm::Constant *C) const { |
| return CGM.getTargetData().getTypeAllocSize(C->getType()); |
| } |
| |
| public: |
| static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, |
| InitListExpr *ILE) { |
| ConstStructBuilder Builder(CGM, CGF); |
| |
| if (!Builder.Build(ILE)) |
| return 0; |
| |
| llvm::Constant *Result = |
| llvm::ConstantStruct::get(CGM.getLLVMContext(), |
| Builder.Elements, Builder.Packed); |
| |
| assert(llvm::RoundUpToAlignment(Builder.NextFieldOffsetInBytes, |
| Builder.getAlignment(Result)) == |
| Builder.getSizeInBytes(Result) && "Size mismatch!"); |
| |
| return Result; |
| } |
| }; |
| |
| 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 *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { |
| return Visit(E->getInitializer()); |
| } |
| |
| llvm::Constant *EmitMemberFunctionPointer(CXXMethodDecl *MD) { |
| assert(MD->isInstance() && "Member function must not be static!"); |
| |
| MD = MD->getCanonicalDecl(); |
| |
| const llvm::Type *PtrDiffTy = |
| CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType()); |
| |
| llvm::Constant *Values[2]; |
| |
| // Get the function pointer (or index if this is a virtual function). |
| if (MD->isVirtual()) { |
| uint64_t Index = CGM.getVtableInfo().getMethodVtableIndex(MD); |
| |
| // Itanium C++ ABI 2.3: |
| // For a non-virtual function, this field is a simple function pointer. |
| // For a virtual function, it is 1 plus the virtual table offset |
| // (in bytes) of the function, represented as a ptrdiff_t. |
| Values[0] = llvm::ConstantInt::get(PtrDiffTy, (Index * 8) + 1); |
| } else { |
| const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>(); |
| const llvm::Type *Ty = |
| CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD), |
| FPT->isVariadic()); |
| |
| llvm::Constant *FuncPtr = CGM.GetAddrOfFunction(MD, Ty); |
| Values[0] = llvm::ConstantExpr::getPtrToInt(FuncPtr, PtrDiffTy); |
| } |
| |
| // The adjustment will always be 0. |
| Values[1] = llvm::ConstantInt::get(PtrDiffTy, 0); |
| |
| return llvm::ConstantStruct::get(CGM.getLLVMContext(), |
| Values, 2, /*Packed=*/false); |
| } |
| |
| llvm::Constant *VisitUnaryAddrOf(UnaryOperator *E) { |
| if (const MemberPointerType *MPT = |
| E->getType()->getAs<MemberPointerType>()) { |
| QualType T = MPT->getPointeeType(); |
| DeclRefExpr *DRE = cast<DeclRefExpr>(E->getSubExpr()); |
| |
| NamedDecl *ND = DRE->getDecl(); |
| if (T->isFunctionProtoType()) |
| return EmitMemberFunctionPointer(cast<CXXMethodDecl>(ND)); |
| |
| // We have a pointer to data member. |
| return CGM.EmitPointerToDataMember(cast<FieldDecl>(ND)); |
| } |
| |
| return 0; |
| } |
| |
| llvm::Constant *VisitBinSub(BinaryOperator *E) { |
| // This must be a pointer/pointer subtraction. This only happens for |
| // address of label. |
| if (!isa<AddrLabelExpr>(E->getLHS()->IgnoreParenNoopCasts(CGM.getContext())) || |
| !isa<AddrLabelExpr>(E->getRHS()->IgnoreParenNoopCasts(CGM.getContext()))) |
| return 0; |
| |
| llvm::Constant *LHS = CGM.EmitConstantExpr(E->getLHS(), |
| E->getLHS()->getType(), CGF); |
| llvm::Constant *RHS = CGM.EmitConstantExpr(E->getRHS(), |
| E->getRHS()->getType(), CGF); |
| |
| const llvm::Type *ResultType = ConvertType(E->getType()); |
| LHS = llvm::ConstantExpr::getPtrToInt(LHS, ResultType); |
| RHS = llvm::ConstantExpr::getPtrToInt(RHS, ResultType); |
| |
| // No need to divide by element size, since addr of label is always void*, |
| // which has size 1 in GNUish. |
| return llvm::ConstantExpr::getSub(LHS, RHS); |
| } |
| |
| llvm::Constant *VisitCastExpr(CastExpr* E) { |
| switch (E->getCastKind()) { |
| case CastExpr::CK_ToUnion: { |
| // GCC cast to union extension |
| assert(E->getType()->isUnionType() && |
| "Destination type is not union type!"); |
| const llvm::Type *Ty = ConvertType(E->getType()); |
| Expr *SubExpr = E->getSubExpr(); |
| |
| llvm::Constant *C = |
| CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF); |
| if (!C) |
| return 0; |
| |
| // Build a struct with the union sub-element as the first member, |
| // and padded to the appropriate size |
| std::vector<llvm::Constant*> Elts; |
| std::vector<const llvm::Type*> Types; |
| Elts.push_back(C); |
| Types.push_back(C->getType()); |
| unsigned CurSize = CGM.getTargetData().getTypeAllocSize(C->getType()); |
| unsigned TotalSize = CGM.getTargetData().getTypeAllocSize(Ty); |
| |
| assert(CurSize <= TotalSize && "Union size mismatch!"); |
| if (unsigned NumPadBytes = TotalSize - CurSize) { |
| const llvm::Type *Ty = llvm::Type::getInt8Ty(VMContext); |
| 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 CastExpr::CK_NullToMemberPointer: |
| return CGM.EmitNullConstant(E->getType()); |
| |
| case CastExpr::CK_BaseToDerivedMemberPointer: { |
| Expr *SubExpr = E->getSubExpr(); |
| |
| const MemberPointerType *SrcTy = |
| SubExpr->getType()->getAs<MemberPointerType>(); |
| const MemberPointerType *DestTy = |
| E->getType()->getAs<MemberPointerType>(); |
| |
| const CXXRecordDecl *BaseClass = |
| cast<CXXRecordDecl>(cast<RecordType>(SrcTy->getClass())->getDecl()); |
| const CXXRecordDecl *DerivedClass = |
| cast<CXXRecordDecl>(cast<RecordType>(DestTy->getClass())->getDecl()); |
| |
| if (SrcTy->getPointeeType()->isFunctionProtoType()) { |
| llvm::Constant *C = |
| CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF); |
| if (!C) |
| return 0; |
| |
| llvm::ConstantStruct *CS = cast<llvm::ConstantStruct>(C); |
| |
| // Check if we need to update the adjustment. |
| if (llvm::Constant *Offset = |
| CGM.GetNonVirtualBaseClassOffset(DerivedClass, BaseClass)) { |
| llvm::Constant *Values[2]; |
| |
| Values[0] = CS->getOperand(0); |
| Values[1] = llvm::ConstantExpr::getAdd(CS->getOperand(1), Offset); |
| return llvm::ConstantStruct::get(CGM.getLLVMContext(), Values, 2, |
| /*Packed=*/false); |
| } |
| |
| return CS; |
| } |
| } |
| |
| case CastExpr::CK_BitCast: |
| // This must be a member function pointer cast. |
| return Visit(E->getSubExpr()); |
| |
| default: { |
| // FIXME: This should be handled by the CK_NoOp cast kind. |
| // Explicit and implicit no-op casts |
| QualType Ty = E->getType(), SubTy = E->getSubExpr()->getType(); |
| if (CGM.getContext().hasSameUnqualifiedType(Ty, SubTy)) |
| return Visit(E->getSubExpr()); |
| |
| // Handle integer->integer casts for address-of-label differences. |
| if (Ty->isIntegerType() && SubTy->isIntegerType() && |
| CGF) { |
| llvm::Value *Src = Visit(E->getSubExpr()); |
| if (Src == 0) return 0; |
| |
| // Use EmitScalarConversion to perform the conversion. |
| return cast<llvm::Constant>(CGF->EmitScalarConversion(Src, SubTy, Ty)); |
| } |
| |
| return 0; |
| } |
| } |
| } |
| |
| llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { |
| return Visit(DAE->getExpr()); |
| } |
| |
| llvm::Constant *EmitArrayInitialization(InitListExpr *ILE) { |
| std::vector<llvm::Constant*> Elts; |
| const llvm::ArrayType *AType = |
| cast<llvm::ArrayType>(ConvertType(ILE->getType())); |
| unsigned NumInitElements = ILE->getNumInits(); |
| // FIXME: Check for wide strings |
| // FIXME: Check for NumInitElements exactly equal to 1?? |
| if (NumInitElements > 0 && |
| (isa<StringLiteral>(ILE->getInit(0)) || |
| isa<ObjCEncodeExpr>(ILE->getInit(0))) && |
| ILE->getType()->getArrayElementTypeNoTypeQual()->isCharType()) |
| return Visit(ILE->getInit(0)); |
| const llvm::Type *ElemTy = AType->getElementType(); |
| 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. |
| unsigned i = 0; |
| bool RewriteType = false; |
| for (; 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! |
| for (; i < NumElements; ++i) |
| Elts.push_back(llvm::Constant::getNullValue(ElemTy)); |
| |
| if (RewriteType) { |
| // FIXME: Try to avoid packing the array |
| std::vector<const llvm::Type*> Types; |
| for (unsigned i = 0; i < Elts.size(); ++i) |
| Types.push_back(Elts[i]->getType()); |
| const llvm::StructType *SType = llvm::StructType::get(AType->getContext(), |
| Types, true); |
| return llvm::ConstantStruct::get(SType, Elts); |
| } |
| |
| return llvm::ConstantArray::get(AType, Elts); |
| } |
| |
| llvm::Constant *EmitStructInitialization(InitListExpr *ILE) { |
| return ConstStructBuilder::BuildStruct(CGM, CGF, ILE); |
| } |
| |
| llvm::Constant *EmitUnionInitialization(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()->isScalarType()) { |
| // We have a scalar in braces. Just use the first element. |
| if (ILE->getNumInits() > 0) { |
| Expr *Init = ILE->getInit(0); |
| return CGM.EmitConstantExpr(Init, Init->getType(), CGF); |
| } |
| return CGM.EmitNullConstant(ILE->getType()); |
| } |
| |
| if (ILE->getType()->isArrayType()) |
| return EmitArrayInitialization(ILE); |
| |
| if (ILE->getType()->isRecordType()) |
| return EmitStructInitialization(ILE); |
| |
| if (ILE->getType()->isUnionType()) |
| return EmitUnionInitialization(ILE); |
| |
| // If ILE was a constant vector, we would have handled it already. |
| if (ILE->getType()->isVectorType()) |
| return 0; |
| |
| assert(0 && "Unable to handle InitListExpr"); |
| // Get rid of control reaches end of void function warning. |
| // Not reached. |
| 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()->isCopyConstructor() && |
| "trivial ctor has argument but isn't a copy 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) { |
| assert(!E->getType()->isPointerType() && "Strings are always arrays"); |
| |
| // This must be a string 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. |
| return llvm::ConstantArray::get(VMContext, |
| CGM.GetStringForStringLiteral(E), false); |
| } |
| |
| 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::ConstantArray::get(VMContext, Str, false); |
| } |
| |
| llvm::Constant *VisitUnaryExtension(const UnaryOperator *E) { |
| return Visit(E->getSubExpr()); |
| } |
| |
| // Utility methods |
| const llvm::Type *ConvertType(QualType T) { |
| return CGM.getTypes().ConvertType(T); |
| } |
| |
| public: |
| llvm::Constant *EmitLValue(Expr *E) { |
| 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 = Visit(CLE->getInitializer()); |
| // 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, false, |
| E->getType().getAddressSpace()); |
| return C; |
| } |
| case Expr::DeclRefExprClass: { |
| ValueDecl *Decl = cast<DeclRefExpr>(E)->getDecl(); |
| 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->isBlockVarDecl()) { |
| assert(CGF && "Can't access static local vars without CGF"); |
| return CGF->GetAddrOfStaticLocalVar(VD); |
| } |
| } |
| } |
| break; |
| } |
| 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->EmitPredefinedFunctionName(Type); |
| 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(CGM.getContext()); |
| 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()); |
| } |
| } |
| |
| return 0; |
| } |
| }; |
| |
| } // end anonymous namespace. |
| |
| 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->Evaluate(Result, Context); |
| |
| if (Success && !Result.HasSideEffects) { |
| switch (Result.Val.getKind()) { |
| case APValue::Uninitialized: |
| assert(0 && "Constant expressions should be initialized."); |
| return 0; |
| case APValue::LValue: { |
| const llvm::Type *DestTy = getTypes().ConvertTypeForMem(DestType); |
| llvm::Constant *Offset = |
| llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), |
| Result.Val.getLValueOffset().getQuantity()); |
| |
| llvm::Constant *C; |
| if (const Expr *LVBase = Result.Val.getLValueBase()) { |
| C = ConstExprEmitter(*this, CGF).EmitLValue(const_cast<Expr*>(LVBase)); |
| |
| // Apply offset if necessary. |
| if (!Offset->isNullValue()) { |
| const llvm::Type *Type = llvm::Type::getInt8PtrTy(VMContext); |
| llvm::Constant *Casted = llvm::ConstantExpr::getBitCast(C, Type); |
| Casted = llvm::ConstantExpr::getGetElementPtr(Casted, &Offset, 1); |
| 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: { |
| llvm::Constant *C = llvm::ConstantInt::get(VMContext, |
| Result.Val.getInt()); |
| |
| if (C->getType() == llvm::Type::getInt1Ty(VMContext)) { |
| const llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType()); |
| C = llvm::ConstantExpr::getZExt(C, BoolTy); |
| } |
| return C; |
| } |
| case APValue::ComplexInt: { |
| llvm::Constant *Complex[2]; |
| |
| Complex[0] = llvm::ConstantInt::get(VMContext, |
| Result.Val.getComplexIntReal()); |
| Complex[1] = llvm::ConstantInt::get(VMContext, |
| Result.Val.getComplexIntImag()); |
| |
| // FIXME: the target may want to specify that this is packed. |
| return llvm::ConstantStruct::get(VMContext, Complex, 2, false); |
| } |
| case APValue::Float: |
| return llvm::ConstantFP::get(VMContext, Result.Val.getFloat()); |
| case APValue::ComplexFloat: { |
| llvm::Constant *Complex[2]; |
| |
| Complex[0] = llvm::ConstantFP::get(VMContext, |
| Result.Val.getComplexFloatReal()); |
| Complex[1] = llvm::ConstantFP::get(VMContext, |
| Result.Val.getComplexFloatImag()); |
| |
| // FIXME: the target may want to specify that this is packed. |
| return llvm::ConstantStruct::get(VMContext, Complex, 2, false); |
| } |
| case APValue::Vector: { |
| llvm::SmallVector<llvm::Constant *, 4> Inits; |
| unsigned NumElts = Result.Val.getVectorLength(); |
| |
| for (unsigned i = 0; i != NumElts; ++i) { |
| APValue &Elt = Result.Val.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[0], Inits.size()); |
| } |
| } |
| } |
| |
| llvm::Constant* C = ConstExprEmitter(*this, CGF).Visit(const_cast<Expr*>(E)); |
| if (C && C->getType() == llvm::Type::getInt1Ty(VMContext)) { |
| const llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType()); |
| C = llvm::ConstantExpr::getZExt(C, BoolTy); |
| } |
| return C; |
| } |
| |
| static bool containsPointerToDataMember(CodeGenTypes &Types, QualType T) { |
| // No need to check for member pointers when not compiling C++. |
| if (!Types.getContext().getLangOptions().CPlusPlus) |
| return false; |
| |
| T = Types.getContext().getBaseElementType(T); |
| |
| if (const RecordType *RT = T->getAs<RecordType>()) { |
| const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); |
| |
| // FIXME: It would be better if there was a way to explicitly compute the |
| // record layout instead of converting to a type. |
| Types.ConvertTagDeclType(RD); |
| |
| const CGRecordLayout &Layout = Types.getCGRecordLayout(RD); |
| return Layout.containsPointerToDataMember(); |
| } |
| |
| if (const MemberPointerType *MPT = T->getAs<MemberPointerType>()) |
| return !MPT->getPointeeType()->isFunctionType(); |
| |
| return false; |
| } |
| |
| llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) { |
| if (!containsPointerToDataMember(getTypes(), T)) |
| return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T)); |
| |
| if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) { |
| |
| QualType ElementTy = CAT->getElementType(); |
| |
| llvm::Constant *Element = EmitNullConstant(ElementTy); |
| unsigned NumElements = CAT->getSize().getZExtValue(); |
| std::vector<llvm::Constant *> Array(NumElements); |
| for (unsigned i = 0; i != NumElements; ++i) |
| Array[i] = Element; |
| |
| const llvm::ArrayType *ATy = |
| cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T)); |
| return llvm::ConstantArray::get(ATy, Array); |
| } |
| |
| if (const RecordType *RT = T->getAs<RecordType>()) { |
| const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); |
| assert(!RD->getNumBases() && |
| "FIXME: Handle zero-initializing structs with bases and " |
| "pointers to data members."); |
| const llvm::StructType *STy = |
| cast<llvm::StructType>(getTypes().ConvertTypeForMem(T)); |
| unsigned NumElements = STy->getNumElements(); |
| std::vector<llvm::Constant *> Elements(NumElements); |
| |
| for (RecordDecl::field_iterator I = RD->field_begin(), |
| E = RD->field_end(); I != E; ++I) { |
| const FieldDecl *FD = *I; |
| |
| unsigned FieldNo = getTypes().getLLVMFieldNo(FD); |
| Elements[FieldNo] = EmitNullConstant(FD->getType()); |
| } |
| |
| // 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(STy->getElementType(i)); |
| } |
| |
| return llvm::ConstantStruct::get(STy, Elements); |
| } |
| |
| 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 llvm::ConstantInt::get(getTypes().ConvertTypeForMem(T), -1ULL, |
| /*isSigned=*/true); |
| } |
| |
| llvm::Constant * |
| CodeGenModule::EmitPointerToDataMember(const FieldDecl *FD) { |
| |
| // 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 |
| |
| const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(FD->getParent()); |
| QualType ClassType = |
| getContext().getTypeDeclType(const_cast<CXXRecordDecl *>(ClassDecl)); |
| |
| const llvm::StructType *ClassLTy = |
| cast<llvm::StructType>(getTypes().ConvertType(ClassType)); |
| |
| unsigned FieldNo = getTypes().getLLVMFieldNo(FD); |
| uint64_t Offset = |
| getTargetData().getStructLayout(ClassLTy)->getElementOffset(FieldNo); |
| |
| const llvm::Type *PtrDiffTy = |
| getTypes().ConvertType(getContext().getPointerDiffType()); |
| |
| return llvm::ConstantInt::get(PtrDiffTy, Offset); |
| } |
