//===- llvm/DataLayout.h - Data size & alignment info -----------*- C++ -*-===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file defines layout properties related to datatype size/offset/alignment // information. It uses lazy annotations to cache information about how // structure types are laid out and used. // // This structure should be created once, filled in if the defaults are not // correct and then passed around by const&. None of the members functions // require modification to the object. // //===----------------------------------------------------------------------===// #ifndef LLVM_IR_DATALAYOUT_H #define LLVM_IR_DATALAYOUT_H #include "llvm/ADT/APInt.h" #include "llvm/ADT/ArrayRef.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/StringRef.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Type.h" #include "llvm/Support/Alignment.h" #include "llvm/Support/Casting.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/TrailingObjects.h" #include "llvm/Support/TypeSize.h" #include #include #include // This needs to be outside of the namespace, to avoid conflict with llvm-c // decl. using LLVMTargetDataRef = struct LLVMOpaqueTargetData *; namespace llvm { class GlobalVariable; class LLVMContext; class Module; class StructLayout; class Triple; class Value; /// Enum used to categorize the alignment types stored by LayoutAlignElem enum AlignTypeEnum { INTEGER_ALIGN = 'i', VECTOR_ALIGN = 'v', FLOAT_ALIGN = 'f', AGGREGATE_ALIGN = 'a' }; // FIXME: Currently the DataLayout string carries a "preferred alignment" // for types. As the DataLayout is module/global, this should likely be // sunk down to an FTTI element that is queried rather than a global // preference. /// Layout alignment element. /// /// Stores the alignment data associated with a given type bit width. /// /// \note The unusual order of elements in the structure attempts to reduce /// padding and make the structure slightly more cache friendly. struct LayoutAlignElem { uint32_t TypeBitWidth; Align ABIAlign; Align PrefAlign; static LayoutAlignElem get(Align ABIAlign, Align PrefAlign, uint32_t BitWidth); bool operator==(const LayoutAlignElem &rhs) const; }; /// Layout pointer alignment element. /// /// Stores the alignment data associated with a given pointer and address space. /// /// \note The unusual order of elements in the structure attempts to reduce /// padding and make the structure slightly more cache friendly. struct PointerAlignElem { Align ABIAlign; Align PrefAlign; uint32_t TypeBitWidth; uint32_t AddressSpace; uint32_t IndexBitWidth; /// Initializer static PointerAlignElem getInBits(uint32_t AddressSpace, Align ABIAlign, Align PrefAlign, uint32_t TypeBitWidth, uint32_t IndexBitWidth); bool operator==(const PointerAlignElem &rhs) const; }; /// A parsed version of the target data layout string in and methods for /// querying it. /// /// The target data layout string is specified *by the target* - a frontend /// generating LLVM IR is required to generate the right target data for the /// target being codegen'd to. class DataLayout { public: enum class FunctionPtrAlignType { /// The function pointer alignment is independent of the function alignment. Independent, /// The function pointer alignment is a multiple of the function alignment. MultipleOfFunctionAlign, }; private: /// Defaults to false. bool BigEndian; unsigned AllocaAddrSpace; MaybeAlign StackNaturalAlign; unsigned ProgramAddrSpace; unsigned DefaultGlobalsAddrSpace; MaybeAlign FunctionPtrAlign; FunctionPtrAlignType TheFunctionPtrAlignType; enum ManglingModeT { MM_None, MM_ELF, MM_MachO, MM_WinCOFF, MM_WinCOFFX86, MM_GOFF, MM_Mips, MM_XCOFF }; ManglingModeT ManglingMode; SmallVector LegalIntWidths; /// Primitive type alignment data. This is sorted by type and bit /// width during construction. using AlignmentsTy = SmallVector; AlignmentsTy IntAlignments; AlignmentsTy FloatAlignments; AlignmentsTy VectorAlignments; LayoutAlignElem StructAlignment; /// The string representation used to create this DataLayout std::string StringRepresentation; using PointersTy = SmallVector; PointersTy Pointers; const PointerAlignElem &getPointerAlignElem(uint32_t AddressSpace) const; // The StructType -> StructLayout map. mutable void *LayoutMap = nullptr; /// Pointers in these address spaces are non-integral, and don't have a /// well-defined bitwise representation. SmallVector NonIntegralAddressSpaces; /// Attempts to set the alignment of the given type. Returns an error /// description on failure. Error setAlignment(AlignTypeEnum AlignType, Align ABIAlign, Align PrefAlign, uint32_t BitWidth); /// Attempts to set the alignment of a pointer in the given address space. /// Returns an error description on failure. Error setPointerAlignmentInBits(uint32_t AddrSpace, Align ABIAlign, Align PrefAlign, uint32_t TypeBitWidth, uint32_t IndexBitWidth); /// Internal helper to get alignment for integer of given bitwidth. Align getIntegerAlignment(uint32_t BitWidth, bool abi_or_pref) const; /// Internal helper method that returns requested alignment for type. Align getAlignment(Type *Ty, bool abi_or_pref) const; /// Attempts to parse a target data specification string and reports an error /// if the string is malformed. Error parseSpecifier(StringRef Desc); // Free all internal data structures. void clear(); public: /// Constructs a DataLayout from a specification string. See reset(). explicit DataLayout(StringRef LayoutDescription) { reset(LayoutDescription); } /// Initialize target data from properties stored in the module. explicit DataLayout(const Module *M); DataLayout(const DataLayout &DL) { *this = DL; } ~DataLayout(); // Not virtual, do not subclass this class DataLayout &operator=(const DataLayout &DL) { clear(); StringRepresentation = DL.StringRepresentation; BigEndian = DL.isBigEndian(); AllocaAddrSpace = DL.AllocaAddrSpace; StackNaturalAlign = DL.StackNaturalAlign; FunctionPtrAlign = DL.FunctionPtrAlign; TheFunctionPtrAlignType = DL.TheFunctionPtrAlignType; ProgramAddrSpace = DL.ProgramAddrSpace; DefaultGlobalsAddrSpace = DL.DefaultGlobalsAddrSpace; ManglingMode = DL.ManglingMode; LegalIntWidths = DL.LegalIntWidths; IntAlignments = DL.IntAlignments; FloatAlignments = DL.FloatAlignments; VectorAlignments = DL.VectorAlignments; StructAlignment = DL.StructAlignment; Pointers = DL.Pointers; NonIntegralAddressSpaces = DL.NonIntegralAddressSpaces; return *this; } bool operator==(const DataLayout &Other) const; bool operator!=(const DataLayout &Other) const { return !(*this == Other); } void init(const Module *M); /// Parse a data layout string (with fallback to default values). void reset(StringRef LayoutDescription); /// Parse a data layout string and return the layout. Return an error /// description on failure. static Expected parse(StringRef LayoutDescription); /// Layout endianness... bool isLittleEndian() const { return !BigEndian; } bool isBigEndian() const { return BigEndian; } /// Returns the string representation of the DataLayout. /// /// This representation is in the same format accepted by the string /// constructor above. This should not be used to compare two DataLayout as /// different string can represent the same layout. const std::string &getStringRepresentation() const { return StringRepresentation; } /// Test if the DataLayout was constructed from an empty string. bool isDefault() const { return StringRepresentation.empty(); } /// Returns true if the specified type is known to be a native integer /// type supported by the CPU. /// /// For example, i64 is not native on most 32-bit CPUs and i37 is not native /// on any known one. This returns false if the integer width is not legal. /// /// The width is specified in bits. bool isLegalInteger(uint64_t Width) const { return llvm::is_contained(LegalIntWidths, Width); } bool isIllegalInteger(uint64_t Width) const { return !isLegalInteger(Width); } /// Returns true if the given alignment exceeds the natural stack alignment. bool exceedsNaturalStackAlignment(Align Alignment) const { return StackNaturalAlign && (Alignment > *StackNaturalAlign); } Align getStackAlignment() const { assert(StackNaturalAlign && "StackNaturalAlign must be defined"); return *StackNaturalAlign; } unsigned getAllocaAddrSpace() const { return AllocaAddrSpace; } PointerType *getAllocaPtrType(LLVMContext &Ctx) const { return PointerType::get(Ctx, AllocaAddrSpace); } /// Returns the alignment of function pointers, which may or may not be /// related to the alignment of functions. /// \see getFunctionPtrAlignType MaybeAlign getFunctionPtrAlign() const { return FunctionPtrAlign; } /// Return the type of function pointer alignment. /// \see getFunctionPtrAlign FunctionPtrAlignType getFunctionPtrAlignType() const { return TheFunctionPtrAlignType; } unsigned getProgramAddressSpace() const { return ProgramAddrSpace; } unsigned getDefaultGlobalsAddressSpace() const { return DefaultGlobalsAddrSpace; } bool hasMicrosoftFastStdCallMangling() const { return ManglingMode == MM_WinCOFFX86; } /// Returns true if symbols with leading question marks should not receive IR /// mangling. True for Windows mangling modes. bool doNotMangleLeadingQuestionMark() const { return ManglingMode == MM_WinCOFF || ManglingMode == MM_WinCOFFX86; } bool hasLinkerPrivateGlobalPrefix() const { return ManglingMode == MM_MachO; } StringRef getLinkerPrivateGlobalPrefix() const { if (ManglingMode == MM_MachO) return "l"; return ""; } char getGlobalPrefix() const { switch (ManglingMode) { case MM_None: case MM_ELF: case MM_GOFF: case MM_Mips: case MM_WinCOFF: case MM_XCOFF: return '\0'; case MM_MachO: case MM_WinCOFFX86: return '_'; } llvm_unreachable("invalid mangling mode"); } StringRef getPrivateGlobalPrefix() const { switch (ManglingMode) { case MM_None: return ""; case MM_ELF: case MM_WinCOFF: return ".L"; case MM_GOFF: return "@"; case MM_Mips: return "$"; case MM_MachO: case MM_WinCOFFX86: return "L"; case MM_XCOFF: return "L.."; } llvm_unreachable("invalid mangling mode"); } static const char *getManglingComponent(const Triple &T); /// Returns true if the specified type fits in a native integer type /// supported by the CPU. /// /// For example, if the CPU only supports i32 as a native integer type, then /// i27 fits in a legal integer type but i45 does not. bool fitsInLegalInteger(unsigned Width) const { for (unsigned LegalIntWidth : LegalIntWidths) if (Width <= LegalIntWidth) return true; return false; } /// Layout pointer alignment Align getPointerABIAlignment(unsigned AS) const; /// Return target's alignment for stack-based pointers /// FIXME: The defaults need to be removed once all of /// the backends/clients are updated. Align getPointerPrefAlignment(unsigned AS = 0) const; /// Layout pointer size in bytes, rounded up to a whole /// number of bytes. /// FIXME: The defaults need to be removed once all of /// the backends/clients are updated. unsigned getPointerSize(unsigned AS = 0) const; /// Returns the maximum index size over all address spaces. unsigned getMaxIndexSize() const; // Index size in bytes used for address calculation, /// rounded up to a whole number of bytes. unsigned getIndexSize(unsigned AS) const; /// Return the address spaces containing non-integral pointers. Pointers in /// this address space don't have a well-defined bitwise representation. ArrayRef getNonIntegralAddressSpaces() const { return NonIntegralAddressSpaces; } bool isNonIntegralAddressSpace(unsigned AddrSpace) const { ArrayRef NonIntegralSpaces = getNonIntegralAddressSpaces(); return is_contained(NonIntegralSpaces, AddrSpace); } bool isNonIntegralPointerType(PointerType *PT) const { return isNonIntegralAddressSpace(PT->getAddressSpace()); } bool isNonIntegralPointerType(Type *Ty) const { auto *PTy = dyn_cast(Ty); return PTy && isNonIntegralPointerType(PTy); } /// Layout pointer size, in bits /// FIXME: The defaults need to be removed once all of /// the backends/clients are updated. unsigned getPointerSizeInBits(unsigned AS = 0) const { return getPointerAlignElem(AS).TypeBitWidth; } /// Returns the maximum index size over all address spaces. unsigned getMaxIndexSizeInBits() const { return getMaxIndexSize() * 8; } /// Size in bits of index used for address calculation in getelementptr. unsigned getIndexSizeInBits(unsigned AS) const { return getPointerAlignElem(AS).IndexBitWidth; } /// Layout pointer size, in bits, based on the type. If this function is /// called with a pointer type, then the type size of the pointer is returned. /// If this function is called with a vector of pointers, then the type size /// of the pointer is returned. This should only be called with a pointer or /// vector of pointers. unsigned getPointerTypeSizeInBits(Type *) const; /// Layout size of the index used in GEP calculation. /// The function should be called with pointer or vector of pointers type. unsigned getIndexTypeSizeInBits(Type *Ty) const; unsigned getPointerTypeSize(Type *Ty) const { return getPointerTypeSizeInBits(Ty) / 8; } /// Size examples: /// /// Type SizeInBits StoreSizeInBits AllocSizeInBits[*] /// ---- ---------- --------------- --------------- /// i1 1 8 8 /// i8 8 8 8 /// i19 19 24 32 /// i32 32 32 32 /// i100 100 104 128 /// i128 128 128 128 /// Float 32 32 32 /// Double 64 64 64 /// X86_FP80 80 80 96 /// /// [*] The alloc size depends on the alignment, and thus on the target. /// These values are for x86-32 linux. /// Returns the number of bits necessary to hold the specified type. /// /// If Ty is a scalable vector type, the scalable property will be set and /// the runtime size will be a positive integer multiple of the base size. /// /// For example, returns 36 for i36 and 80 for x86_fp80. The type passed must /// have a size (Type::isSized() must return true). TypeSize getTypeSizeInBits(Type *Ty) const; /// Returns the maximum number of bytes that may be overwritten by /// storing the specified type. /// /// If Ty is a scalable vector type, the scalable property will be set and /// the runtime size will be a positive integer multiple of the base size. /// /// For example, returns 5 for i36 and 10 for x86_fp80. TypeSize getTypeStoreSize(Type *Ty) const { TypeSize BaseSize = getTypeSizeInBits(Ty); return {divideCeil(BaseSize.getKnownMinValue(), 8), BaseSize.isScalable()}; } /// Returns the maximum number of bits that may be overwritten by /// storing the specified type; always a multiple of 8. /// /// If Ty is a scalable vector type, the scalable property will be set and /// the runtime size will be a positive integer multiple of the base size. /// /// For example, returns 40 for i36 and 80 for x86_fp80. TypeSize getTypeStoreSizeInBits(Type *Ty) const { return 8 * getTypeStoreSize(Ty); } /// Returns true if no extra padding bits are needed when storing the /// specified type. /// /// For example, returns false for i19 that has a 24-bit store size. bool typeSizeEqualsStoreSize(Type *Ty) const { return getTypeSizeInBits(Ty) == getTypeStoreSizeInBits(Ty); } /// Returns the offset in bytes between successive objects of the /// specified type, including alignment padding. /// /// If Ty is a scalable vector type, the scalable property will be set and /// the runtime size will be a positive integer multiple of the base size. /// /// This is the amount that alloca reserves for this type. For example, /// returns 12 or 16 for x86_fp80, depending on alignment. TypeSize getTypeAllocSize(Type *Ty) const { // Round up to the next alignment boundary. return alignTo(getTypeStoreSize(Ty), getABITypeAlign(Ty).value()); } /// Returns the offset in bits between successive objects of the /// specified type, including alignment padding; always a multiple of 8. /// /// If Ty is a scalable vector type, the scalable property will be set and /// the runtime size will be a positive integer multiple of the base size. /// /// This is the amount that alloca reserves for this type. For example, /// returns 96 or 128 for x86_fp80, depending on alignment. TypeSize getTypeAllocSizeInBits(Type *Ty) const { return 8 * getTypeAllocSize(Ty); } /// Returns the minimum ABI-required alignment for the specified type. Align getABITypeAlign(Type *Ty) const; /// Helper function to return `Alignment` if it's set or the result of /// `getABITypeAlign(Ty)`, in any case the result is a valid alignment. inline Align getValueOrABITypeAlignment(MaybeAlign Alignment, Type *Ty) const { return Alignment ? *Alignment : getABITypeAlign(Ty); } /// Returns the minimum ABI-required alignment for an integer type of /// the specified bitwidth. Align getABIIntegerTypeAlignment(unsigned BitWidth) const { return getIntegerAlignment(BitWidth, /* abi_or_pref */ true); } /// Returns the preferred stack/global alignment for the specified /// type. /// /// This is always at least as good as the ABI alignment. /// FIXME: Deprecate this function once migration to Align is over. LLVM_DEPRECATED("use getPrefTypeAlign instead", "getPrefTypeAlign") uint64_t getPrefTypeAlignment(Type *Ty) const; /// Returns the preferred stack/global alignment for the specified /// type. /// /// This is always at least as good as the ABI alignment. Align getPrefTypeAlign(Type *Ty) const; /// Returns an integer type with size at least as big as that of a /// pointer in the given address space. IntegerType *getIntPtrType(LLVMContext &C, unsigned AddressSpace = 0) const; /// Returns an integer (vector of integer) type with size at least as /// big as that of a pointer of the given pointer (vector of pointer) type. Type *getIntPtrType(Type *) const; /// Returns the smallest integer type with size at least as big as /// Width bits. Type *getSmallestLegalIntType(LLVMContext &C, unsigned Width = 0) const; /// Returns the largest legal integer type, or null if none are set. Type *getLargestLegalIntType(LLVMContext &C) const { unsigned LargestSize = getLargestLegalIntTypeSizeInBits(); return (LargestSize == 0) ? nullptr : Type::getIntNTy(C, LargestSize); } /// Returns the size of largest legal integer type size, or 0 if none /// are set. unsigned getLargestLegalIntTypeSizeInBits() const; /// Returns the type of a GEP index in AddressSpace. /// If it was not specified explicitly, it will be the integer type of the /// pointer width - IntPtrType. IntegerType *getIndexType(LLVMContext &C, unsigned AddressSpace) const; /// Returns the type of a GEP index. /// If it was not specified explicitly, it will be the integer type of the /// pointer width - IntPtrType. Type *getIndexType(Type *PtrTy) const; /// Returns the offset from the beginning of the type for the specified /// indices. /// /// Note that this takes the element type, not the pointer type. /// This is used to implement getelementptr. int64_t getIndexedOffsetInType(Type *ElemTy, ArrayRef Indices) const; /// Get GEP indices to access Offset inside ElemTy. ElemTy is updated to be /// the result element type and Offset to be the residual offset. SmallVector getGEPIndicesForOffset(Type *&ElemTy, APInt &Offset) const; /// Get single GEP index to access Offset inside ElemTy. Returns std::nullopt /// if index cannot be computed, e.g. because the type is not an aggregate. /// ElemTy is updated to be the result element type and Offset to be the /// residual offset. std::optional getGEPIndexForOffset(Type *&ElemTy, APInt &Offset) const; /// Returns a StructLayout object, indicating the alignment of the /// struct, its size, and the offsets of its fields. /// /// Note that this information is lazily cached. const StructLayout *getStructLayout(StructType *Ty) const; /// Returns the preferred alignment of the specified global. /// /// This includes an explicitly requested alignment (if the global has one). Align getPreferredAlign(const GlobalVariable *GV) const; }; inline DataLayout *unwrap(LLVMTargetDataRef P) { return reinterpret_cast(P); } inline LLVMTargetDataRef wrap(const DataLayout *P) { return reinterpret_cast(const_cast(P)); } /// Used to lazily calculate structure layout information for a target machine, /// based on the DataLayout structure. class StructLayout final : public TrailingObjects { TypeSize StructSize; Align StructAlignment; unsigned IsPadded : 1; unsigned NumElements : 31; public: TypeSize getSizeInBytes() const { return StructSize; } TypeSize getSizeInBits() const { return 8 * StructSize; } Align getAlignment() const { return StructAlignment; } /// Returns whether the struct has padding or not between its fields. /// NB: Padding in nested element is not taken into account. bool hasPadding() const { return IsPadded; } /// Given a valid byte offset into the structure, returns the structure /// index that contains it. unsigned getElementContainingOffset(uint64_t FixedOffset) const; MutableArrayRef getMemberOffsets() { return llvm::MutableArrayRef(getTrailingObjects(), NumElements); } ArrayRef getMemberOffsets() const { return llvm::ArrayRef(getTrailingObjects(), NumElements); } TypeSize getElementOffset(unsigned Idx) const { assert(Idx < NumElements && "Invalid element idx!"); return getMemberOffsets()[Idx]; } TypeSize getElementOffsetInBits(unsigned Idx) const { return getElementOffset(Idx) * 8; } private: friend class DataLayout; // Only DataLayout can create this class StructLayout(StructType *ST, const DataLayout &DL); size_t numTrailingObjects(OverloadToken) const { return NumElements; } }; // The implementation of this method is provided inline as it is particularly // well suited to constant folding when called on a specific Type subclass. inline TypeSize DataLayout::getTypeSizeInBits(Type *Ty) const { assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!"); switch (Ty->getTypeID()) { case Type::LabelTyID: return TypeSize::getFixed(getPointerSizeInBits(0)); case Type::PointerTyID: return TypeSize::getFixed( getPointerSizeInBits(Ty->getPointerAddressSpace())); case Type::ArrayTyID: { ArrayType *ATy = cast(Ty); return ATy->getNumElements() * getTypeAllocSizeInBits(ATy->getElementType()); } case Type::StructTyID: // Get the layout annotation... which is lazily created on demand. return getStructLayout(cast(Ty))->getSizeInBits(); case Type::IntegerTyID: return TypeSize::getFixed(Ty->getIntegerBitWidth()); case Type::HalfTyID: case Type::BFloatTyID: return TypeSize::getFixed(16); case Type::FloatTyID: return TypeSize::getFixed(32); case Type::DoubleTyID: case Type::X86_MMXTyID: return TypeSize::getFixed(64); case Type::PPC_FP128TyID: case Type::FP128TyID: return TypeSize::getFixed(128); case Type::X86_AMXTyID: return TypeSize::getFixed(8192); // In memory objects this is always aligned to a higher boundary, but // only 80 bits contain information. case Type::X86_FP80TyID: return TypeSize::getFixed(80); case Type::FixedVectorTyID: case Type::ScalableVectorTyID: { VectorType *VTy = cast(Ty); auto EltCnt = VTy->getElementCount(); uint64_t MinBits = EltCnt.getKnownMinValue() * getTypeSizeInBits(VTy->getElementType()).getFixedValue(); return TypeSize(MinBits, EltCnt.isScalable()); } case Type::TargetExtTyID: { Type *LayoutTy = cast(Ty)->getLayoutType(); return getTypeSizeInBits(LayoutTy); } default: llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type"); } } } // end namespace llvm #endif // LLVM_IR_DATALAYOUT_H