| //===--- 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 "ConstantEmitter.h" |
| #include "TargetInfo.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 ConstExprEmitter; |
| class ConstStructBuilder { |
| CodeGenModule &CGM; |
| ConstantEmitter &Emitter; |
| |
| bool Packed; |
| CharUnits NextFieldOffsetInChars; |
| CharUnits LLVMStructAlignment; |
| SmallVector<llvm::Constant *, 32> Elements; |
| public: |
| static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, |
| ConstExprEmitter *ExprEmitter, |
| llvm::ConstantStruct *Base, |
| InitListExpr *Updater, |
| QualType ValTy); |
| static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, |
| InitListExpr *ILE, QualType StructTy); |
| static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, |
| const APValue &Value, QualType ValTy); |
| |
| private: |
| ConstStructBuilder(ConstantEmitter &emitter) |
| : CGM(emitter.CGM), Emitter(emitter), Packed(false), |
| NextFieldOffsetInChars(CharUnits::Zero()), |
| LLVMStructAlignment(CharUnits::One()) { } |
| |
| 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); |
| bool Build(ConstExprEmitter *Emitter, llvm::ConstantStruct *Base, |
| InitListExpr *Updater); |
| bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase, |
| 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:: |
| 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.alignTo(FieldAlignment); |
| |
| if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) { |
| // We need to append padding. |
| AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars); |
| |
| assert(NextFieldOffsetInChars == FieldOffsetInChars && |
| "Did not add enough padding!"); |
| |
| AlignedNextFieldOffsetInChars = |
| NextFieldOffsetInChars.alignTo(FieldAlignment); |
| } |
| |
| if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) { |
| assert(!Packed && "Alignment is wrong even with a packed struct!"); |
| |
| // Convert the struct to a packed struct. |
| ConvertStructToPacked(); |
| |
| // After we pack the struct, we may need to insert padding. |
| if (NextFieldOffsetInChars < 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::alignTo(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.lshrInPlace(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.lshrInPlace(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.lshrInPlace(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.alignTo(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) { |
| RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl(); |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| |
| unsigned FieldNo = 0; |
| unsigned ElementNo = 0; |
| |
| // Bail out if we have base classes. We could support these, but they only |
| // arise in C++1z where we will have already constant folded most interesting |
| // cases. FIXME: There are still a few more cases we can handle this way. |
| if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) |
| if (CXXRD->getNumBases()) |
| return false; |
| |
| for (RecordDecl::field_iterator Field = RD->field_begin(), |
| FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { |
| // 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()) |
| 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 = Emitter.tryEmitPrivateForMemory(ILE->getInit(ElementNo++), |
| Field->getType()); |
| else |
| EltInit = Emitter.emitNullForMemory(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. |
| if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) { |
| AppendBitField(*Field, Layout.getFieldOffset(FieldNo), CI); |
| } else { |
| // We are trying to initialize a bitfield with a non-trivial constant, |
| // this must require run-time code. |
| return false; |
| } |
| } |
| } |
| |
| 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; } |
| }; |
| } |
| |
| bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD, |
| bool IsPrimaryBase, |
| 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) { |
| llvm::Constant *VTableAddressPoint = |
| CGM.getCXXABI().getVTableAddressPointForConstExpr( |
| BaseSubobject(CD, Offset), VTableClass); |
| AppendBytes(Offset, VTableAddressPoint); |
| } |
| |
| // 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, |
| VTableClass, Offset + Base.Offset); |
| } |
| } |
| |
| unsigned FieldNo = 0; |
| uint64_t OffsetBits = CGM.getContext().toBits(Offset); |
| |
| for (RecordDecl::field_iterator Field = RD->field_begin(), |
| FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { |
| // 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()) |
| continue; |
| |
| // Emit the value of the initializer. |
| const APValue &FieldValue = |
| RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo); |
| llvm::Constant *EltInit = |
| Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType()); |
| if (!EltInit) |
| return false; |
| |
| 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)); |
| } |
| } |
| |
| return true; |
| } |
| |
| 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. |
| CharUnits LLVMSizeInChars = |
| NextFieldOffsetInChars.alignTo(LLVMStructAlignment); |
| |
| if (LLVMSizeInChars != LayoutSizeInChars) |
| AppendTailPadding(LayoutSizeInChars); |
| |
| LLVMSizeInChars = NextFieldOffsetInChars.alignTo(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!"); |
| } |
| |
| LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment); |
| |
| assert(LayoutSizeInChars == LLVMSizeInChars && |
| "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.alignTo(getAlignment(Result)) == |
| getSizeInChars(Result) && |
| "Size mismatch!"); |
| |
| return Result; |
| } |
| |
| llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter, |
| ConstExprEmitter *ExprEmitter, |
| llvm::ConstantStruct *Base, |
| InitListExpr *Updater, |
| QualType ValTy) { |
| ConstStructBuilder Builder(Emitter); |
| if (!Builder.Build(ExprEmitter, Base, Updater)) |
| return nullptr; |
| return Builder.Finalize(ValTy); |
| } |
| |
| llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter, |
| InitListExpr *ILE, |
| QualType ValTy) { |
| ConstStructBuilder Builder(Emitter); |
| |
| if (!Builder.Build(ILE)) |
| return nullptr; |
| |
| return Builder.Finalize(ValTy); |
| } |
| |
| llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter, |
| const APValue &Val, |
| QualType ValTy) { |
| ConstStructBuilder Builder(Emitter); |
| |
| const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl(); |
| const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD); |
| if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero())) |
| return nullptr; |
| |
| return Builder.Finalize(ValTy); |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // ConstExprEmitter |
| //===----------------------------------------------------------------------===// |
| |
| static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM, |
| CodeGenFunction *CGF, |
| const CompoundLiteralExpr *E) { |
| CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType()); |
| if (llvm::GlobalVariable *Addr = |
| CGM.getAddrOfConstantCompoundLiteralIfEmitted(E)) |
| return ConstantAddress(Addr, Align); |
| |
| LangAS addressSpace = E->getType().getAddressSpace(); |
| |
| ConstantEmitter emitter(CGM, CGF); |
| llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(), |
| addressSpace, E->getType()); |
| if (!C) { |
| assert(!E->isFileScope() && |
| "file-scope compound literal did not have constant initializer!"); |
| return ConstantAddress::invalid(); |
| } |
| |
| auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(), |
| CGM.isTypeConstant(E->getType(), true), |
| llvm::GlobalValue::InternalLinkage, |
| C, ".compoundliteral", nullptr, |
| llvm::GlobalVariable::NotThreadLocal, |
| CGM.getContext().getTargetAddressSpace(addressSpace)); |
| emitter.finalize(GV); |
| GV->setAlignment(Align.getQuantity()); |
| CGM.setAddrOfConstantCompoundLiteral(E, GV); |
| return ConstantAddress(GV, Align); |
| } |
| |
| /// 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*, QualType> { |
| CodeGenModule &CGM; |
| ConstantEmitter &Emitter; |
| llvm::LLVMContext &VMContext; |
| public: |
| ConstExprEmitter(ConstantEmitter &emitter) |
| : CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) { |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Visitor Methods |
| //===--------------------------------------------------------------------===// |
| |
| llvm::Constant *VisitStmt(Stmt *S, QualType T) { |
| return nullptr; |
| } |
| |
| llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) { |
| return Visit(PE->getSubExpr(), T); |
| } |
| |
| llvm::Constant * |
| VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE, |
| QualType T) { |
| return Visit(PE->getReplacement(), T); |
| } |
| |
| llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE, |
| QualType T) { |
| return Visit(GE->getResultExpr(), T); |
| } |
| |
| llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) { |
| return Visit(CE->getChosenSubExpr(), T); |
| } |
| |
| llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) { |
| return Visit(E->getInitializer(), T); |
| } |
| |
| llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) { |
| if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E)) |
| CGM.EmitExplicitCastExprType(ECE, Emitter.CGF); |
| Expr *subExpr = E->getSubExpr(); |
| |
| switch (E->getCastKind()) { |
| case CK_ToUnion: { |
| // GCC cast to union extension |
| assert(E->getType()->isUnionType() && |
| "Destination type is not union type!"); |
| |
| auto field = E->getTargetUnionField(); |
| |
| auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType()); |
| if (!C) return nullptr; |
| |
| auto destTy = ConvertType(destType); |
| if (C->getType() == destTy) return C; |
| |
| // 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(destTy); |
| |
| 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(VMContext, Types, false); |
| return llvm::ConstantStruct::get(STy, Elts); |
| } |
| |
| case CK_AddressSpaceConversion: { |
| auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType()); |
| if (!C) return nullptr; |
| LangAS destAS = E->getType()->getPointeeType().getAddressSpace(); |
| LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace(); |
| llvm::Type *destTy = ConvertType(E->getType()); |
| return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS, |
| destAS, destTy); |
| } |
| |
| case CK_LValueToRValue: |
| case CK_AtomicToNonAtomic: |
| case CK_NonAtomicToAtomic: |
| case CK_NoOp: |
| case CK_ConstructorConversion: |
| return Visit(subExpr, destType); |
| |
| case CK_IntToOCLSampler: |
| llvm_unreachable("global sampler variables are not generated"); |
| |
| 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: { |
| auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType()); |
| if (!C) return nullptr; |
| 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 nullptr; |
| |
| // 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_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_BooleanToSignedIntegral: |
| case CK_IntegralToPointer: |
| case CK_IntegralToBoolean: |
| case CK_IntegralToFloating: |
| case CK_FloatingToIntegral: |
| case CK_FloatingToBoolean: |
| case CK_FloatingCast: |
| case CK_ZeroToOCLEvent: |
| case CK_ZeroToOCLQueue: |
| return nullptr; |
| } |
| llvm_unreachable("Invalid CastKind"); |
| } |
| |
| llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE, QualType T) { |
| return Visit(DAE->getExpr(), T); |
| } |
| |
| llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) { |
| // No need for a DefaultInitExprScope: we don't handle 'this' in a |
| // constant expression. |
| return Visit(DIE->getExpr(), T); |
| } |
| |
| llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) { |
| if (!E->cleanupsHaveSideEffects()) |
| return Visit(E->getSubExpr(), T); |
| return nullptr; |
| } |
| |
| llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E, |
| QualType T) { |
| return Visit(E->GetTemporaryExpr(), T); |
| } |
| |
| llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) { |
| 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); |
| |
| QualType EltType = CGM.getContext().getAsArrayType(T)->getElementType(); |
| |
| // Initialize remaining array elements. |
| llvm::Constant *fillC; |
| if (Expr *filler = ILE->getArrayFiller()) |
| fillC = Emitter.tryEmitAbstractForMemory(filler, EltType); |
| else |
| fillC = Emitter.emitNullForMemory(EltType); |
| if (!fillC) |
| return nullptr; |
| |
| // Try to use a ConstantAggregateZero if we can. |
| if (fillC->isNullValue() && !NumInitableElts) |
| return llvm::ConstantAggregateZero::get(AType); |
| |
| // Copy initializer elements. |
| SmallVector<llvm::Constant*, 16> Elts; |
| Elts.reserve(NumInitableElts + NumElements); |
| |
| bool RewriteType = false; |
| for (unsigned i = 0; i < NumInitableElts; ++i) { |
| Expr *Init = ILE->getInit(i); |
| llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType); |
| if (!C) |
| return nullptr; |
| RewriteType |= (C->getType() != ElemTy); |
| Elts.push_back(C); |
| } |
| |
| 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, QualType T) { |
| return ConstStructBuilder::BuildStruct(Emitter, ILE, T); |
| } |
| |
| llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E, |
| QualType T) { |
| return CGM.EmitNullConstant(T); |
| } |
| |
| llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) { |
| if (ILE->isTransparent()) |
| return Visit(ILE->getInit(0), T); |
| |
| if (ILE->getType()->isArrayType()) |
| return EmitArrayInitialization(ILE, T); |
| |
| if (ILE->getType()->isRecordType()) |
| return EmitRecordInitialization(ILE, T); |
| |
| return nullptr; |
| } |
| |
| llvm::Constant *EmitDesignatedInitUpdater(llvm::Constant *Base, |
| InitListExpr *Updater, |
| QualType destType) { |
| if (auto destAT = CGM.getContext().getAsArrayType(destType)) { |
| llvm::ArrayType *AType = cast<llvm::ArrayType>(ConvertType(destType)); |
| llvm::Type *ElemType = AType->getElementType(); |
| |
| unsigned NumInitElements = Updater->getNumInits(); |
| unsigned NumElements = AType->getNumElements(); |
| |
| std::vector<llvm::Constant *> Elts; |
| Elts.reserve(NumElements); |
| |
| QualType destElemType = destAT->getElementType(); |
| |
| if (auto DataArray = dyn_cast<llvm::ConstantDataArray>(Base)) |
| for (unsigned i = 0; i != NumElements; ++i) |
| Elts.push_back(DataArray->getElementAsConstant(i)); |
| else if (auto Array = dyn_cast<llvm::ConstantArray>(Base)) |
| for (unsigned i = 0; i != NumElements; ++i) |
| Elts.push_back(Array->getOperand(i)); |
| else |
| return nullptr; // FIXME: other array types not implemented |
| |
| llvm::Constant *fillC = nullptr; |
| if (Expr *filler = Updater->getArrayFiller()) |
| if (!isa<NoInitExpr>(filler)) |
| fillC = Emitter.tryEmitAbstractForMemory(filler, destElemType); |
| bool RewriteType = (fillC && fillC->getType() != ElemType); |
| |
| for (unsigned i = 0; i != NumElements; ++i) { |
| Expr *Init = nullptr; |
| if (i < NumInitElements) |
| Init = Updater->getInit(i); |
| |
| if (!Init && fillC) |
| Elts[i] = fillC; |
| else if (!Init || isa<NoInitExpr>(Init)) |
| ; // Do nothing. |
| else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) |
| Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE, destElemType); |
| else |
| Elts[i] = Emitter.tryEmitPrivateForMemory(Init, destElemType); |
| |
| if (!Elts[i]) |
| return nullptr; |
| RewriteType |= (Elts[i]->getType() != ElemType); |
| } |
| |
| if (RewriteType) { |
| std::vector<llvm::Type *> Types; |
| Types.reserve(NumElements); |
| for (unsigned i = 0; i != NumElements; ++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); |
| } |
| |
| if (destType->isRecordType()) |
| return ConstStructBuilder::BuildStruct(Emitter, this, |
| dyn_cast<llvm::ConstantStruct>(Base), Updater, destType); |
| |
| return nullptr; |
| } |
| |
| llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E, |
| QualType destType) { |
| auto C = Visit(E->getBase(), destType); |
| if (!C) return nullptr; |
| return EmitDesignatedInitUpdater(C, E->getUpdater(), destType); |
| } |
| |
| llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) { |
| if (!E->getConstructor()->isTrivial()) |
| return nullptr; |
| |
| // 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 nullptr; |
| |
| // 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, Ty); |
| } |
| |
| return CGM.EmitNullConstant(Ty); |
| } |
| |
| llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) { |
| return CGM.GetConstantArrayFromStringLiteral(E); |
| } |
| |
| llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) { |
| // 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 = CGM.getContext().getAsConstantArrayType(T); |
| |
| // 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, QualType T) { |
| return Visit(E->getSubExpr(), T); |
| } |
| |
| // Utility methods |
| llvm::Type *ConvertType(QualType T) { |
| return CGM.getTypes().ConvertType(T); |
| } |
| }; |
| |
| } // end anonymous namespace. |
| |
| bool ConstStructBuilder::Build(ConstExprEmitter *ExprEmitter, |
| llvm::ConstantStruct *Base, |
| InitListExpr *Updater) { |
| assert(Base && "base expression should not be empty"); |
| |
| QualType ExprType = Updater->getType(); |
| RecordDecl *RD = ExprType->getAs<RecordType>()->getDecl(); |
| const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); |
| const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout( |
| Base->getType()); |
| unsigned FieldNo = -1; |
| unsigned ElementNo = 0; |
| |
| // Bail out if we have base classes. We could support these, but they only |
| // arise in C++1z where we will have already constant folded most interesting |
| // cases. FIXME: There are still a few more cases we can handle this way. |
| if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) |
| if (CXXRD->getNumBases()) |
| return false; |
| |
| for (FieldDecl *Field : RD->fields()) { |
| ++FieldNo; |
| |
| if (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field) |
| continue; |
| |
| // Skip anonymous bitfields. |
| if (Field->isUnnamedBitfield()) |
| continue; |
| |
| llvm::Constant *EltInit = Base->getOperand(ElementNo); |
| |
| // Bail out if the type of the ConstantStruct does not have the same layout |
| // as the type of the InitListExpr. |
| if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() || |
| Layout.getFieldOffset(ElementNo) != |
| BaseLayout->getElementOffsetInBits(ElementNo)) |
| return false; |
| |
| // Get the initializer. If we encounter an empty field or a NoInitExpr, |
| // we use values from the base expression. |
| Expr *Init = nullptr; |
| if (ElementNo < Updater->getNumInits()) |
| Init = Updater->getInit(ElementNo); |
| |
| if (!Init || isa<NoInitExpr>(Init)) |
| ; // Do nothing. |
| else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) |
| EltInit = ExprEmitter->EmitDesignatedInitUpdater(EltInit, ChildILE, |
| Field->getType()); |
| else |
| EltInit = Emitter.tryEmitPrivateForMemory(Init, Field->getType()); |
| |
| ++ElementNo; |
| |
| if (!EltInit) |
| return false; |
| |
| if (!Field->isBitField()) |
| AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit); |
| else if (llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(EltInit)) |
| AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI); |
| else |
| // Initializing a bitfield with a non-trivial constant? |
| return false; |
| } |
| |
| return true; |
| } |
| |
| llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C, |
| AbstractState saved) { |
| Abstract = saved.OldValue; |
| |
| assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() && |
| "created a placeholder while doing an abstract emission?"); |
| |
| // No validation necessary for now. |
| // No cleanup to do for now. |
| return C; |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) { |
| auto state = pushAbstract(); |
| auto C = tryEmitPrivateForVarInit(D); |
| return validateAndPopAbstract(C, state); |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) { |
| auto state = pushAbstract(); |
| auto C = tryEmitPrivate(E, destType); |
| return validateAndPopAbstract(C, state); |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) { |
| auto state = pushAbstract(); |
| auto C = tryEmitPrivate(value, destType); |
| return validateAndPopAbstract(C, state); |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::emitAbstract(const Expr *E, QualType destType) { |
| auto state = pushAbstract(); |
| auto C = tryEmitPrivate(E, destType); |
| C = validateAndPopAbstract(C, state); |
| if (!C) { |
| CGM.Error(E->getExprLoc(), |
| "internal error: could not emit constant value \"abstractly\""); |
| C = CGM.EmitNullConstant(destType); |
| } |
| return C; |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value, |
| QualType destType) { |
| auto state = pushAbstract(); |
| auto C = tryEmitPrivate(value, destType); |
| C = validateAndPopAbstract(C, state); |
| if (!C) { |
| CGM.Error(loc, |
| "internal error: could not emit constant value \"abstractly\""); |
| C = CGM.EmitNullConstant(destType); |
| } |
| return C; |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) { |
| initializeNonAbstract(D.getType().getAddressSpace()); |
| return markIfFailed(tryEmitPrivateForVarInit(D)); |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E, |
| LangAS destAddrSpace, |
| QualType destType) { |
| initializeNonAbstract(destAddrSpace); |
| return markIfFailed(tryEmitPrivateForMemory(E, destType)); |
| } |
| |
| llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value, |
| LangAS destAddrSpace, |
| QualType destType) { |
| initializeNonAbstract(destAddrSpace); |
| auto C = tryEmitPrivateForMemory(value, destType); |
| assert(C && "couldn't emit constant value non-abstractly?"); |
| return C; |
| } |
| |
| llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() { |
| assert(!Abstract && "cannot get current address for abstract constant"); |
| |
| |
| |
| // Make an obviously ill-formed global that should blow up compilation |
| // if it survives. |
| auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true, |
| llvm::GlobalValue::PrivateLinkage, |
| /*init*/ nullptr, |
| /*name*/ "", |
| /*before*/ nullptr, |
| llvm::GlobalVariable::NotThreadLocal, |
| CGM.getContext().getTargetAddressSpace(DestAddressSpace)); |
| |
| PlaceholderAddresses.push_back(std::make_pair(nullptr, global)); |
| |
| return global; |
| } |
| |
| void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal, |
| llvm::GlobalValue *placeholder) { |
| assert(!PlaceholderAddresses.empty()); |
| assert(PlaceholderAddresses.back().first == nullptr); |
| assert(PlaceholderAddresses.back().second == placeholder); |
| PlaceholderAddresses.back().first = signal; |
| } |
| |
| namespace { |
| struct ReplacePlaceholders { |
| CodeGenModule &CGM; |
| |
| /// The base address of the global. |
| llvm::Constant *Base; |
| llvm::Type *BaseValueTy = nullptr; |
| |
| /// The placeholder addresses that were registered during emission. |
| llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses; |
| |
| /// The locations of the placeholder signals. |
| llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations; |
| |
| /// The current index stack. We use a simple unsigned stack because |
| /// we assume that placeholders will be relatively sparse in the |
| /// initializer, but we cache the index values we find just in case. |
| llvm::SmallVector<unsigned, 8> Indices; |
| llvm::SmallVector<llvm::Constant*, 8> IndexValues; |
| |
| ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base, |
| ArrayRef<std::pair<llvm::Constant*, |
| llvm::GlobalVariable*>> addresses) |
| : CGM(CGM), Base(base), |
| PlaceholderAddresses(addresses.begin(), addresses.end()) { |
| } |
| |
| void replaceInInitializer(llvm::Constant *init) { |
| // Remember the type of the top-most initializer. |
| BaseValueTy = init->getType(); |
| |
| // Initialize the stack. |
| Indices.push_back(0); |
| IndexValues.push_back(nullptr); |
| |
| // Recurse into the initializer. |
| findLocations(init); |
| |
| // Check invariants. |
| assert(IndexValues.size() == Indices.size() && "mismatch"); |
| assert(Indices.size() == 1 && "didn't pop all indices"); |
| |
| // Do the replacement; this basically invalidates 'init'. |
| assert(Locations.size() == PlaceholderAddresses.size() && |
| "missed a placeholder?"); |
| |
| // We're iterating over a hashtable, so this would be a source of |
| // non-determinism in compiler output *except* that we're just |
| // messing around with llvm::Constant structures, which never itself |
| // does anything that should be visible in compiler output. |
| for (auto &entry : Locations) { |
| assert(entry.first->getParent() == nullptr && "not a placeholder!"); |
| entry.first->replaceAllUsesWith(entry.second); |
| entry.first->eraseFromParent(); |
| } |
| } |
| |
| private: |
| void findLocations(llvm::Constant *init) { |
| // Recurse into aggregates. |
| if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) { |
| for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) { |
| Indices.push_back(i); |
| IndexValues.push_back(nullptr); |
| |
| findLocations(agg->getOperand(i)); |
| |
| IndexValues.pop_back(); |
| Indices.pop_back(); |
| } |
| return; |
| } |
| |
| // Otherwise, check for registered constants. |
| while (true) { |
| auto it = PlaceholderAddresses.find(init); |
| if (it != PlaceholderAddresses.end()) { |
| setLocation(it->second); |
| break; |
| } |
| |
| // Look through bitcasts or other expressions. |
| if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) { |
| init = expr->getOperand(0); |
| } else { |
| break; |
| } |
| } |
| } |
| |
| void setLocation(llvm::GlobalVariable *placeholder) { |
| assert(Locations.find(placeholder) == Locations.end() && |
| "already found location for placeholder!"); |
| |
| // Lazily fill in IndexValues with the values from Indices. |
| // We do this in reverse because we should always have a strict |
| // prefix of indices from the start. |
| assert(Indices.size() == IndexValues.size()); |
| for (size_t i = Indices.size() - 1; i != size_t(-1); --i) { |
| if (IndexValues[i]) { |
| #ifndef NDEBUG |
| for (size_t j = 0; j != i + 1; ++j) { |
| assert(IndexValues[j] && |
| isa<llvm::ConstantInt>(IndexValues[j]) && |
| cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() |
| == Indices[j]); |
| } |
| #endif |
| break; |
| } |
| |
| IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]); |
| } |
| |
| // Form a GEP and then bitcast to the placeholder type so that the |
| // replacement will succeed. |
| llvm::Constant *location = |
| llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy, |
| Base, IndexValues); |
| location = llvm::ConstantExpr::getBitCast(location, |
| placeholder->getType()); |
| |
| Locations.insert({placeholder, location}); |
| } |
| }; |
| } |
| |
| void ConstantEmitter::finalize(llvm::GlobalVariable *global) { |
| assert(InitializedNonAbstract && |
| "finalizing emitter that was used for abstract emission?"); |
| assert(!Finalized && "finalizing emitter multiple times"); |
| assert(global->getInitializer()); |
| |
| // Note that we might also be Failed. |
| Finalized = true; |
| |
| if (!PlaceholderAddresses.empty()) { |
| ReplacePlaceholders(CGM, global, PlaceholderAddresses) |
| .replaceInInitializer(global->getInitializer()); |
| PlaceholderAddresses.clear(); // satisfy |
| } |
| } |
| |
| ConstantEmitter::~ConstantEmitter() { |
| assert((!InitializedNonAbstract || Finalized || Failed) && |
| "not finalized after being initialized for non-abstract emission"); |
| assert(PlaceholderAddresses.empty() && "unhandled placeholders"); |
| } |
| |
| static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) { |
| if (auto AT = type->getAs<AtomicType>()) { |
| return CGM.getContext().getQualifiedType(AT->getValueType(), |
| type.getQualifiers()); |
| } |
| return type; |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) { |
| // 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 = CGM.getContext().getBaseElementType(D.getType()); |
| 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 CGM.EmitNullConstant(D.getType()); |
| } |
| } |
| |
| QualType destType = D.getType(); |
| |
| // Try to emit the initializer. Note that this can allow some things that |
| // are not allowed by tryEmitPrivateForMemory alone. |
| if (auto value = D.evaluateValue()) { |
| return tryEmitPrivateForMemory(*value, destType); |
| } |
| |
| // 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 (destType->isReferenceType()) |
| return nullptr; |
| |
| const Expr *E = D.getInit(); |
| assert(E && "No initializer to emit"); |
| |
| auto nonMemoryDestType = getNonMemoryType(CGM, destType); |
| auto C = |
| ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType); |
| return (C ? emitForMemory(C, destType) : nullptr); |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) { |
| auto nonMemoryDestType = getNonMemoryType(CGM, destType); |
| auto C = tryEmitAbstract(E, nonMemoryDestType); |
| return (C ? emitForMemory(C, destType) : nullptr); |
| } |
| |
| llvm::Constant * |
| ConstantEmitter::tryEmitAbstractForMemory(const APValue &value, |
| QualType destType) { |
| auto nonMemoryDestType = getNonMemoryType(CGM, destType); |
| auto C = tryEmitAbstract(value, nonMemoryDestType); |
| return (C ? emitForMemory(C, destType) : nullptr); |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E, |
| QualType destType) { |
| auto nonMemoryDestType = getNonMemoryType(CGM, destType); |
| llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType); |
| return (C ? emitForMemory(C, destType) : nullptr); |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value, |
| QualType destType) { |
| auto nonMemoryDestType = getNonMemoryType(CGM, destType); |
| auto C = tryEmitPrivate(value, nonMemoryDestType); |
| return (C ? emitForMemory(C, destType) : nullptr); |
| } |
| |
| llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM, |
| llvm::Constant *C, |
| QualType destType) { |
| // For an _Atomic-qualified constant, we may need to add tail padding. |
| if (auto AT = destType->getAs<AtomicType>()) { |
| QualType destValueType = AT->getValueType(); |
| C = emitForMemory(CGM, C, destValueType); |
| |
| uint64_t innerSize = CGM.getContext().getTypeSize(destValueType); |
| uint64_t outerSize = CGM.getContext().getTypeSize(destType); |
| if (innerSize == outerSize) |
| return C; |
| |
| assert(innerSize < outerSize && "emitted over-large constant for atomic"); |
| llvm::Constant *elts[] = { |
| C, |
| llvm::ConstantAggregateZero::get( |
| llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8)) |
| }; |
| return llvm::ConstantStruct::getAnon(elts); |
| } |
| |
| // Zero-extend bool. |
| if (C->getType()->isIntegerTy(1)) { |
| llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType); |
| return llvm::ConstantExpr::getZExt(C, boolTy); |
| } |
| |
| return C; |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E, |
| QualType destType) { |
| Expr::EvalResult Result; |
| |
| bool Success = false; |
| |
| if (destType->isReferenceType()) |
| Success = E->EvaluateAsLValue(Result, CGM.getContext()); |
| else |
| Success = E->EvaluateAsRValue(Result, CGM.getContext()); |
| |
| llvm::Constant *C; |
| if (Success && !Result.HasSideEffects) |
| C = tryEmitPrivate(Result.Val, destType); |
| else |
| C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType); |
| |
| return C; |
| } |
| |
| llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) { |
| return getTargetCodeGenInfo().getNullPointer(*this, T, QT); |
| } |
| |
| namespace { |
| /// A struct which can be used to peephole certain kinds of finalization |
| /// that normally happen during l-value emission. |
| struct ConstantLValue { |
| llvm::Constant *Value; |
| bool HasOffsetApplied; |
| |
| /*implicit*/ ConstantLValue(llvm::Constant *value, |
| bool hasOffsetApplied = false) |
| : Value(value), HasOffsetApplied(false) {} |
| |
| /*implicit*/ ConstantLValue(ConstantAddress address) |
| : ConstantLValue(address.getPointer()) {} |
| }; |
| |
| /// A helper class for emitting constant l-values. |
| class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter, |
| ConstantLValue> { |
| CodeGenModule &CGM; |
| ConstantEmitter &Emitter; |
| const APValue &Value; |
| QualType DestType; |
| |
| // Befriend StmtVisitorBase so that we don't have to expose Visit*. |
| friend StmtVisitorBase; |
| |
| public: |
| ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value, |
| QualType destType) |
| : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {} |
| |
| llvm::Constant *tryEmit(); |
| |
| private: |
| llvm::Constant *tryEmitAbsolute(llvm::Type *destTy); |
| ConstantLValue tryEmitBase(const APValue::LValueBase &base); |
| |
| ConstantLValue VisitStmt(const Stmt *S) { return nullptr; } |
| ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); |
| ConstantLValue VisitStringLiteral(const StringLiteral *E); |
| ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E); |
| ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E); |
| ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E); |
| ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E); |
| ConstantLValue VisitCallExpr(const CallExpr *E); |
| ConstantLValue VisitBlockExpr(const BlockExpr *E); |
| ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E); |
| ConstantLValue VisitCXXUuidofExpr(const CXXUuidofExpr *E); |
| ConstantLValue VisitMaterializeTemporaryExpr( |
| const MaterializeTemporaryExpr *E); |
| |
| bool hasNonZeroOffset() const { |
| return !Value.getLValueOffset().isZero(); |
| } |
| |
| /// Return the value offset. |
| llvm::Constant *getOffset() { |
| return llvm::ConstantInt::get(CGM.Int64Ty, |
| Value.getLValueOffset().getQuantity()); |
| } |
| |
| /// Apply the value offset to the given constant. |
| llvm::Constant *applyOffset(llvm::Constant *C) { |
| if (!hasNonZeroOffset()) |
| return C; |
| |
| llvm::Type *origPtrTy = C->getType(); |
| unsigned AS = origPtrTy->getPointerAddressSpace(); |
| llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS); |
| C = llvm::ConstantExpr::getBitCast(C, charPtrTy); |
| C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset()); |
| C = llvm::ConstantExpr::getPointerCast(C, origPtrTy); |
| return C; |
| } |
| }; |
| |
| } |
| |
| llvm::Constant *ConstantLValueEmitter::tryEmit() { |
| const APValue::LValueBase &base = Value.getLValueBase(); |
| |
| // Certain special array initializers are represented in APValue |
| // as l-values referring to the base expression which generates the |
| // array. This happens with e.g. string literals. These should |
| // probably just get their own representation kind in APValue. |
| if (DestType->isArrayType()) { |
| assert(!hasNonZeroOffset() && "offset on array initializer"); |
| auto expr = const_cast<Expr*>(base.get<const Expr*>()); |
| return ConstExprEmitter(Emitter).Visit(expr, DestType); |
| } |
| |
| // Otherwise, the destination type should be a pointer or reference |
| // type, but it might also be a cast thereof. |
| // |
| // FIXME: the chain of casts required should be reflected in the APValue. |
| // We need this in order to correctly handle things like a ptrtoint of a |
| // non-zero null pointer and addrspace casts that aren't trivially |
| // represented in LLVM IR. |
| auto destTy = CGM.getTypes().ConvertTypeForMem(DestType); |
| assert(isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy)); |
| |
| // If there's no base at all, this is a null or absolute pointer, |
| // possibly cast back to an integer type. |
| if (!base) { |
| return tryEmitAbsolute(destTy); |
| } |
| |
| // Otherwise, try to emit the base. |
| ConstantLValue result = tryEmitBase(base); |
| |
| // If that failed, we're done. |
| llvm::Constant *value = result.Value; |
| if (!value) return nullptr; |
| |
| // Apply the offset if necessary and not already done. |
| if (!result.HasOffsetApplied) { |
| value = applyOffset(value); |
| } |
| |
| // Convert to the appropriate type; this could be an lvalue for |
| // an integer. FIXME: performAddrSpaceCast |
| if (isa<llvm::PointerType>(destTy)) |
| return llvm::ConstantExpr::getPointerCast(value, destTy); |
| |
| return llvm::ConstantExpr::getPtrToInt(value, destTy); |
| } |
| |
| /// Try to emit an absolute l-value, such as a null pointer or an integer |
| /// bitcast to pointer type. |
| llvm::Constant * |
| ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) { |
| auto offset = getOffset(); |
| |
| // If we're producing a pointer, this is easy. |
| if (auto destPtrTy = cast<llvm::PointerType>(destTy)) { |
| if (Value.isNullPointer()) { |
| // FIXME: integer offsets from non-zero null pointers. |
| return CGM.getNullPointer(destPtrTy, DestType); |
| } |
| |
| // Convert the integer to a pointer-sized integer before converting it |
| // to a pointer. |
| // FIXME: signedness depends on the original integer type. |
| auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy); |
| llvm::Constant *C = offset; |
| C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy, |
| /*isSigned*/ false); |
| C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy); |
| return C; |
| } |
| |
| // Otherwise, we're basically returning an integer constant. |
| |
| // FIXME: this does the wrong thing with ptrtoint of a null pointer, |
| // but since we don't know the original pointer type, there's not much |
| // we can do about it. |
| |
| auto C = getOffset(); |
| C = llvm::ConstantExpr::getIntegerCast(C, destTy, /*isSigned*/ false); |
| return C; |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) { |
| // Handle values. |
| if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) { |
| if (D->hasAttr<WeakRefAttr>()) |
| return CGM.GetWeakRefReference(D).getPointer(); |
| |
| if (auto FD = dyn_cast<FunctionDecl>(D)) |
| return CGM.GetAddrOfFunction(FD); |
| |
| if (auto VD = dyn_cast<VarDecl>(D)) { |
| // We can never refer to a variable with local storage. |
| if (!VD->hasLocalStorage()) { |
| if (VD->isFileVarDecl() || VD->hasExternalStorage()) |
| return CGM.GetAddrOfGlobalVar(VD); |
| |
| if (VD->isLocalVarDecl()) { |
| return CGM.getOrCreateStaticVarDecl( |
| *VD, CGM.getLLVMLinkageVarDefinition(VD, /*isConstant=*/false)); |
| } |
| } |
| } |
| |
| return nullptr; |
| } |
| |
| // Otherwise, it must be an expression. |
| return Visit(base.get<const Expr*>()); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { |
| return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) { |
| return CGM.GetAddrOfConstantStringFromLiteral(E); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { |
| return CGM.GetAddrOfConstantStringFromObjCEncode(E); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) { |
| auto C = CGM.getObjCRuntime().GenerateConstantString(E->getString()); |
| return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(E->getType())); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) { |
| if (auto CGF = Emitter.CGF) { |
| LValue Res = CGF->EmitPredefinedLValue(E); |
| return cast<ConstantAddress>(Res.getAddress()); |
| } |
| |
| auto kind = E->getIdentType(); |
| if (kind == PredefinedExpr::PrettyFunction) { |
| return CGM.GetAddrOfConstantCString("top level", ".tmp"); |
| } |
| |
| return CGM.GetAddrOfConstantCString("", ".tmp"); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) { |
| assert(Emitter.CGF && "Invalid address of label expression outside function"); |
| llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel()); |
| Ptr = llvm::ConstantExpr::getBitCast(Ptr, |
| CGM.getTypes().ConvertType(E->getType())); |
| return Ptr; |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) { |
| unsigned builtin = E->getBuiltinCallee(); |
| if (builtin != Builtin::BI__builtin___CFStringMakeConstantString && |
| builtin != Builtin::BI__builtin___NSStringMakeConstantString) |
| return nullptr; |
| |
| auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts()); |
| if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) { |
| return CGM.getObjCRuntime().GenerateConstantString(literal); |
| } else { |
| // FIXME: need to deal with UCN conversion issues. |
| return CGM.GetAddrOfConstantCFString(literal); |
| } |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) { |
| StringRef functionName; |
| if (auto CGF = Emitter.CGF) |
| functionName = CGF->CurFn->getName(); |
| else |
| functionName = "global"; |
| |
| return CGM.GetAddrOfGlobalBlock(E, functionName); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) { |
| QualType T; |
| if (E->isTypeOperand()) |
| T = E->getTypeOperand(CGM.getContext()); |
| else |
| T = E->getExprOperand()->getType(); |
| return CGM.GetAddrOfRTTIDescriptor(T); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitCXXUuidofExpr(const CXXUuidofExpr *E) { |
| return CGM.GetAddrOfUuidDescriptor(E); |
| } |
| |
| ConstantLValue |
| ConstantLValueEmitter::VisitMaterializeTemporaryExpr( |
| const MaterializeTemporaryExpr *E) { |
| assert(E->getStorageDuration() == SD_Static); |
| SmallVector<const Expr *, 2> CommaLHSs; |
| SmallVector<SubobjectAdjustment, 2> Adjustments; |
| const Expr *Inner = E->GetTemporaryExpr() |
| ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments); |
| return CGM.GetAddrOfGlobalTemporary(E, Inner); |
| } |
| |
| llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value, |
| QualType DestType) { |
| switch (Value.getKind()) { |
| case APValue::Uninitialized: |
| llvm_unreachable("Constant expressions should be initialized."); |
| case APValue::LValue: |
| return ConstantLValueEmitter(*this, Value, DestType).tryEmit(); |
| case APValue::Int: |
| return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt()); |
| case APValue::ComplexInt: { |
| llvm::Constant *Complex[2]; |
| |
| Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(), |
| Value.getComplexIntReal()); |
| Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(), |
| 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()); |
| return llvm::ConstantStruct::get(STy, Complex); |
| } |
| case APValue::Float: { |
| const llvm::APFloat &Init = Value.getFloat(); |
| if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() && |
| !CGM.getContext().getLangOpts().NativeHalfType && |
| CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics()) |
| return llvm::ConstantInt::get(CGM.getLLVMContext(), |
| Init.bitcastToAPInt()); |
| else |
| return llvm::ConstantFP::get(CGM.getLLVMContext(), Init); |
| } |
| case APValue::ComplexFloat: { |
| llvm::Constant *Complex[2]; |
| |
| Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(), |
| Value.getComplexFloatReal()); |
| Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(), |
| 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()); |
| return llvm::ConstantStruct::get(STy, Complex); |
| } |
| case APValue::Vector: { |
| unsigned NumElts = Value.getVectorLength(); |
| SmallVector<llvm::Constant *, 4> Inits(NumElts); |
| |
| for (unsigned I = 0; I != NumElts; ++I) { |
| const APValue &Elt = Value.getVectorElt(I); |
| if (Elt.isInt()) |
| Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt()); |
| else if (Elt.isFloat()) |
| Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat()); |
| else |
| llvm_unreachable("unsupported vector element type"); |
| } |
| return llvm::ConstantVector::get(Inits); |
| } |
| case APValue::AddrLabelDiff: { |
| const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS(); |
| const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS(); |
| llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType()); |
| llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType()); |
| if (!LHS || !RHS) return nullptr; |
| |
| // Compute difference |
| llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType); |
| LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy); |
| RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.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, Value, DestType); |
| case APValue::Array: { |
| const ArrayType *CAT = CGM.getContext().getAsArrayType(DestType); |
| unsigned NumElements = Value.getArraySize(); |
| unsigned NumInitElts = Value.getArrayInitializedElts(); |
| |
| // Emit array filler, if there is one. |
| llvm::Constant *Filler = nullptr; |
| if (Value.hasArrayFiller()) |
| Filler = tryEmitAbstractForMemory(Value.getArrayFiller(), |
| CAT->getElementType()); |
| |
| // Emit initializer elements. |
| llvm::Type *CommonElementType = |
| CGM.getTypes().ConvertType(CAT->getElementType()); |
| |
| // Try to use a ConstantAggregateZero if we can. |
| if (Filler && Filler->isNullValue() && !NumInitElts) { |
| llvm::ArrayType *AType = |
| llvm::ArrayType::get(CommonElementType, NumElements); |
| return llvm::ConstantAggregateZero::get(AType); |
| } |
| |
| SmallVector<llvm::Constant*, 16> Elts; |
| Elts.reserve(NumElements); |
| for (unsigned I = 0; I < NumElements; ++I) { |
| llvm::Constant *C = Filler; |
| if (I < NumInitElts) { |
| C = tryEmitPrivateForMemory(Value.getArrayInitializedElt(I), |
| CAT->getElementType()); |
| } else if (!Filler) { |
| assert(Value.hasArrayFiller() && |
| "Missing filler for implicit elements of initializer"); |
| C = tryEmitPrivateForMemory(Value.getArrayFiller(), |
| CAT->getElementType()); |
| } |
| if (!C) return nullptr; |
| |
| if (I == 0) |
| CommonElementType = C->getType(); |
| else if (C->getType() != CommonElementType) |
| CommonElementType = nullptr; |
| 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(CGM.getLLVMContext(), 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 CGM.getCXXABI().EmitMemberPointer(Value, DestType); |
| } |
| llvm_unreachable("Unknown APValue kind"); |
| } |
| |
| llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted( |
| const CompoundLiteralExpr *E) { |
| return EmittedCompoundLiterals.lookup(E); |
| } |
| |
| void CodeGenModule::setAddrOfConstantCompoundLiteral( |
| const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) { |
| bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second; |
| (void)Ok; |
| assert(Ok && "CLE has already been emitted!"); |
| } |
| |
| ConstantAddress |
| CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) { |
| assert(E->isFileScope() && "not a file-scope compound literal expr"); |
| return tryEmitGlobalCompoundLiteral(*this, nullptr, 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().EmitMemberFunctionPointer(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 llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM, |
| llvm::Type *baseType, |
| const CXXRecordDecl *base); |
| |
| static llvm::Constant *EmitNullConstant(CodeGenModule &CGM, |
| const RecordDecl *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); |
| |
| auto CXXR = dyn_cast<CXXRecordDecl>(record); |
| // Fill in all the bases. |
| if (CXXR) { |
| for (const auto &I : CXXR->bases()) { |
| 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() || |
| CGM.getContext().getASTRecordLayout(base).getNonVirtualSize() |
| .isZero()) |
| continue; |
| |
| unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base); |
| llvm::Type *baseType = structure->getElementType(fieldIndex); |
| elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base); |
| } |
| } |
| |
| // Fill in all the fields. |
| for (const auto *Field : record->fields()) { |
| // 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()) { |
| if (Field->getIdentifier()) |
| break; |
| if (const auto *FieldRD = |
| dyn_cast_or_null<RecordDecl>(Field->getType()->getAsTagDecl())) |
| if (FieldRD->findFirstNamedDataMember()) |
| break; |
| } |
| } |
| |
| // Fill in the virtual bases, if we're working with the complete object. |
| if (CXXR && asCompleteObject) { |
| for (const auto &I : CXXR->vbases()) { |
| 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); |
| |
| // Otherwise, we can just use its null constant. |
| return EmitNullConstant(CGM, base, /*asCompleteObject=*/false); |
| } |
| |
| llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM, |
| QualType T) { |
| return emitForMemory(CGM, CGM.EmitNullConstant(T), T); |
| } |
| |
| llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) { |
| if (T->getAs<PointerType>()) |
| return getNullPointer( |
| cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), 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 = |
| ConstantEmitter::emitNullForMemory(*this, ElementTy); |
| unsigned NumElements = CAT->getSize().getZExtValue(); |
| SmallVector<llvm::Constant *, 8> Array(NumElements, Element); |
| return llvm::ConstantArray::get(ATy, Array); |
| } |
| |
| if (const RecordType *RT = T->getAs<RecordType>()) |
| return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true); |
| |
| assert(T->isMemberDataPointerType() && |
| "Should only see pointers to data members here!"); |
| |
| return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>()); |
| } |
| |
| llvm::Constant * |
| CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) { |
| return ::EmitNullConstant(*this, Record, false); |
| } |