//===--------- llvm/DataLayout.h - Data size & alignment info ---*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // 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/DenseMap.h" #include "llvm/ADT/SmallVector.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Type.h" #include "llvm/Pass.h" #include "llvm/Support/DataTypes.h" namespace llvm { class Value; class Type; class IntegerType; class StructType; class StructLayout; class Triple; class GlobalVariable; class LLVMContext; template<typename T> class ArrayRef; /// Enum used to categorize the alignment types stored by LayoutAlignElem enum AlignTypeEnum { INVALID_ALIGN = 0, ///< An invalid alignment INTEGER_ALIGN = 'i', ///< Integer type alignment VECTOR_ALIGN = 'v', ///< Vector type alignment FLOAT_ALIGN = 'f', ///< Floating point type alignment AGGREGATE_ALIGN = 'a' ///< Aggregate alignment }; /// Layout alignment element. /// /// Stores the alignment data associated with a given alignment type (integer, /// vector, float) and 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 { unsigned AlignType : 8; ///< Alignment type (AlignTypeEnum) unsigned TypeBitWidth : 24; ///< Type bit width unsigned ABIAlign : 16; ///< ABI alignment for this type/bitw unsigned PrefAlign : 16; ///< Pref. alignment for this type/bitw /// Initializer static LayoutAlignElem get(AlignTypeEnum align_type, unsigned abi_align, unsigned pref_align, uint32_t bit_width); /// Equality predicate 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 { unsigned ABIAlign; ///< ABI alignment for this type/bitw unsigned PrefAlign; ///< Pref. alignment for this type/bitw uint32_t TypeByteWidth; ///< Type byte width uint32_t AddressSpace; ///< Address space for the pointer type /// Initializer static PointerAlignElem get(uint32_t AddressSpace, unsigned ABIAlign, unsigned PrefAlign, uint32_t TypeByteWidth); /// Equality predicate bool operator==(const PointerAlignElem &rhs) const; }; /// DataLayout - This class holds a parsed version of the target data layout /// string in a module and provides 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. If some measure of portability is desired, an empty string may be /// specified in the module. class DataLayout : public ImmutablePass { private: bool LittleEndian; ///< Defaults to false unsigned StackNaturalAlign; ///< Stack natural alignment enum ManglingModeT { MM_None, MM_ELF, MM_MachO, MM_WINCOFF, MM_Mips }; ManglingModeT ManglingMode; SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers. /// Alignments - Where the primitive type alignment data is stored. /// /// @sa init(). /// @note Could support multiple size pointer alignments, e.g., 32-bit /// pointers vs. 64-bit pointers by extending LayoutAlignment, but for now, /// we don't. SmallVector<LayoutAlignElem, 16> Alignments; DenseMap<unsigned, PointerAlignElem> Pointers; /// InvalidAlignmentElem - This member is a signal that a requested alignment /// type and bit width were not found in the SmallVector. static const LayoutAlignElem InvalidAlignmentElem; /// InvalidPointerElem - This member is a signal that a requested pointer /// type and bit width were not found in the DenseSet. static const PointerAlignElem InvalidPointerElem; // The StructType -> StructLayout map. mutable void *LayoutMap; //! Set/initialize target alignments void setAlignment(AlignTypeEnum align_type, unsigned abi_align, unsigned pref_align, uint32_t bit_width); unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width, bool ABIAlign, Type *Ty) const; //! Set/initialize pointer alignments void setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign, unsigned PrefAlign, uint32_t TypeByteWidth); //! Internal helper method that returns requested alignment for type. unsigned getAlignment(Type *Ty, bool abi_or_pref) const; /// Valid alignment predicate. /// /// Predicate that tests a LayoutAlignElem reference returned by get() against /// InvalidAlignmentElem. bool validAlignment(const LayoutAlignElem &align) const { return &align != &InvalidAlignmentElem; } /// Valid pointer predicate. /// /// Predicate that tests a PointerAlignElem reference returned by get() against /// InvalidPointerElem. bool validPointer(const PointerAlignElem &align) const { return &align != &InvalidPointerElem; } /// Parses a target data specification string. Assert if the string is /// malformed. void parseSpecifier(StringRef LayoutDescription); public: /// Default ctor. /// /// @note This has to exist, because this is a pass, but it should never be /// used. DataLayout(); /// Constructs a DataLayout from a specification string. See init(). explicit DataLayout(StringRef LayoutDescription) : ImmutablePass(ID) { init(LayoutDescription); } /// Initialize target data from properties stored in the module. explicit DataLayout(const Module *M); DataLayout(const DataLayout &DL) : ImmutablePass(ID), LittleEndian(DL.isLittleEndian()), StackNaturalAlign(DL.StackNaturalAlign), ManglingMode(DL.ManglingMode), LegalIntWidths(DL.LegalIntWidths), Alignments(DL.Alignments), Pointers(DL.Pointers), LayoutMap(0) { } ~DataLayout(); // Not virtual, do not subclass this class /// DataLayout is an immutable pass, but holds state. This allows the pass /// manager to clear its mutable state. bool doFinalization(Module &M); /// Parse a data layout string (with fallback to default values). Ensure that /// the data layout pass is registered. void init(StringRef LayoutDescription); /// Layout endianness... bool isLittleEndian() const { return LittleEndian; } bool isBigEndian() const { return !LittleEndian; } /// getStringRepresentation - Return the string representation of the /// DataLayout. This representation is in the same format accepted by the /// string constructor above. std::string getStringRepresentation() const; /// isLegalInteger - This function 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(unsigned Width) const { for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i) if (LegalIntWidths[i] == Width) return true; return false; } bool isIllegalInteger(unsigned Width) const { return !isLegalInteger(Width); } /// Returns true if the given alignment exceeds the natural stack alignment. bool exceedsNaturalStackAlignment(unsigned Align) const { return (StackNaturalAlign != 0) && (Align > StackNaturalAlign); } bool hasMicrosoftFastStdCallMangling() const { return ManglingMode == MM_WINCOFF; } bool hasLinkerPrivateGlobalPrefix() const { return ManglingMode == MM_MachO; } const char *getLinkerPrivateGlobalPrefix() const { if (ManglingMode == MM_MachO) return "l"; return getPrivateGlobalPrefix(); } char getGlobalPrefix() const { switch (ManglingMode) { case MM_None: case MM_ELF: case MM_Mips: return '\0'; case MM_MachO: case MM_WINCOFF: return '_'; } llvm_unreachable("invalid mangling mode"); } const char *getPrivateGlobalPrefix() const { switch (ManglingMode) { case MM_None: return ""; case MM_ELF: return ".L"; case MM_Mips: return "$"; case MM_MachO: case MM_WINCOFF: return "L"; } llvm_unreachable("invalid mangling mode"); } static const char *getManglingComponent(const Triple &T); /// fitsInLegalInteger - This function 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 i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i) if (Width <= LegalIntWidths[i]) return true; return false; } /// Layout pointer alignment /// FIXME: The defaults need to be removed once all of /// the backends/clients are updated. unsigned getPointerABIAlignment(unsigned AS = 0) const { DenseMap<unsigned, PointerAlignElem>::const_iterator val = Pointers.find(AS); if (val == Pointers.end()) { val = Pointers.find(0); } return val->second.ABIAlign; } /// Return target's alignment for stack-based pointers /// FIXME: The defaults need to be removed once all of /// the backends/clients are updated. unsigned getPointerPrefAlignment(unsigned AS = 0) const { DenseMap<unsigned, PointerAlignElem>::const_iterator val = Pointers.find(AS); if (val == Pointers.end()) { val = Pointers.find(0); } return val->second.PrefAlign; } /// Layout pointer size /// FIXME: The defaults need to be removed once all of /// the backends/clients are updated. unsigned getPointerSize(unsigned AS = 0) const { DenseMap<unsigned, PointerAlignElem>::const_iterator val = Pointers.find(AS); if (val == Pointers.end()) { val = Pointers.find(0); } return val->second.TypeByteWidth; } /// 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 getPointerSize(AS) * 8; } /// 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; 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. /// getTypeSizeInBits - Return the number of bits necessary to hold the /// specified type. For example, returns 36 for i36 and 80 for x86_fp80. /// The type passed must have a size (Type::isSized() must return true). uint64_t getTypeSizeInBits(Type *Ty) const; /// getTypeStoreSize - Return the maximum number of bytes that may be /// overwritten by storing the specified type. For example, returns 5 /// for i36 and 10 for x86_fp80. uint64_t getTypeStoreSize(Type *Ty) const { return (getTypeSizeInBits(Ty)+7)/8; } /// getTypeStoreSizeInBits - Return the maximum number of bits that may be /// overwritten by storing the specified type; always a multiple of 8. For /// example, returns 40 for i36 and 80 for x86_fp80. uint64_t getTypeStoreSizeInBits(Type *Ty) const { return 8*getTypeStoreSize(Ty); } /// getTypeAllocSize - Return the offset in bytes between successive objects /// of the specified type, including alignment padding. This is the amount /// that alloca reserves for this type. For example, returns 12 or 16 for /// x86_fp80, depending on alignment. uint64_t getTypeAllocSize(Type *Ty) const { // Round up to the next alignment boundary. return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty)); } /// getTypeAllocSizeInBits - Return the offset in bits between successive /// objects of the specified type, including alignment padding; always a /// multiple of 8. This is the amount that alloca reserves for this type. /// For example, returns 96 or 128 for x86_fp80, depending on alignment. uint64_t getTypeAllocSizeInBits(Type *Ty) const { return 8*getTypeAllocSize(Ty); } /// getABITypeAlignment - Return the minimum ABI-required alignment for the /// specified type. unsigned getABITypeAlignment(Type *Ty) const; /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for /// an integer type of the specified bitwidth. unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const; /// getPrefTypeAlignment - Return the preferred stack/global alignment for /// the specified type. This is always at least as good as the ABI alignment. unsigned getPrefTypeAlignment(Type *Ty) const; /// getPreferredTypeAlignmentShift - Return the preferred alignment for the /// specified type, returned as log2 of the value (a shift amount). unsigned getPreferredTypeAlignmentShift(Type *Ty) const; /// getIntPtrType - Return 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; /// getIntPtrType - Return 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; /// getSmallestLegalIntType - Return the smallest integer type with size at /// least as big as Width bits. Type *getSmallestLegalIntType(LLVMContext &C, unsigned Width = 0) const; /// getLargestLegalIntType - Return the largest legal integer type, or null if /// none are set. Type *getLargestLegalIntType(LLVMContext &C) const { unsigned LargestSize = getLargestLegalIntTypeSize(); return (LargestSize == 0) ? 0 : Type::getIntNTy(C, LargestSize); } /// getLargestLegalIntType - Return the size of largest legal integer type /// size, or 0 if none are set. unsigned getLargestLegalIntTypeSize() const; /// getIndexedOffset - return the offset from the beginning of the type for /// the specified indices. This is used to implement getelementptr. uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const; /// getStructLayout - Return 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; /// getPreferredAlignment - Return the preferred alignment of the specified /// global. This includes an explicitly requested alignment (if the global /// has one). unsigned getPreferredAlignment(const GlobalVariable *GV) const; /// getPreferredAlignmentLog - Return the preferred alignment of the /// specified global, returned in log form. This includes an explicitly /// requested alignment (if the global has one). unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const; /// RoundUpAlignment - Round the specified value up to the next alignment /// boundary specified by Alignment. For example, 7 rounded up to an /// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4 /// is 8 because it is already aligned. template <typename UIntTy> static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) { assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!"); return (Val + (Alignment-1)) & ~UIntTy(Alignment-1); } static char ID; // Pass identification, replacement for typeid }; /// StructLayout - used to lazily calculate structure layout information for a /// target machine, based on the DataLayout structure. /// class StructLayout { uint64_t StructSize; unsigned StructAlignment; unsigned NumElements; uint64_t MemberOffsets[1]; // variable sized array! public: uint64_t getSizeInBytes() const { return StructSize; } uint64_t getSizeInBits() const { return 8*StructSize; } unsigned getAlignment() const { return StructAlignment; } /// getElementContainingOffset - Given a valid byte offset into the structure, /// return the structure index that contains it. /// unsigned getElementContainingOffset(uint64_t Offset) const; uint64_t getElementOffset(unsigned Idx) const { assert(Idx < NumElements && "Invalid element idx!"); return MemberOffsets[Idx]; } uint64_t getElementOffsetInBits(unsigned Idx) const { return getElementOffset(Idx)*8; } private: friend class DataLayout; // Only DataLayout can create this class StructLayout(StructType *ST, const DataLayout &DL); }; // 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 uint64_t DataLayout::getTypeSizeInBits(Type *Ty) const { assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!"); switch (Ty->getTypeID()) { case Type::LabelTyID: return getPointerSizeInBits(0); case Type::PointerTyID: return getPointerSizeInBits(Ty->getPointerAddressSpace()); case Type::ArrayTyID: { ArrayType *ATy = cast<ArrayType>(Ty); return ATy->getNumElements() * getTypeAllocSizeInBits(ATy->getElementType()); } case Type::StructTyID: // Get the layout annotation... which is lazily created on demand. return getStructLayout(cast<StructType>(Ty))->getSizeInBits(); case Type::IntegerTyID: return Ty->getIntegerBitWidth(); case Type::HalfTyID: return 16; case Type::FloatTyID: return 32; case Type::DoubleTyID: case Type::X86_MMXTyID: return 64; case Type::PPC_FP128TyID: case Type::FP128TyID: return 128; // In memory objects this is always aligned to a higher boundary, but // only 80 bits contain information. case Type::X86_FP80TyID: return 80; case Type::VectorTyID: { VectorType *VTy = cast<VectorType>(Ty); return VTy->getNumElements() * getTypeSizeInBits(VTy->getElementType()); } default: llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type"); } } } // End llvm namespace #endif