//===-- llvm/Target/TargetData.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 target 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_TARGET_TARGETDATA_H #define LLVM_TARGET_TARGETDATA_H #include "llvm/Pass.h" #include "llvm/ADT/SmallVector.h" #include "llvm/Support/DataTypes.h" namespace llvm { class Value; class Type; class IntegerType; class StructType; class StructLayout; class GlobalVariable; class LLVMContext; template<typename T> class ArrayRef; /// Enum used to categorize the alignment types stored by TargetAlignElem enum AlignTypeEnum { INTEGER_ALIGN = 'i', ///< Integer type alignment VECTOR_ALIGN = 'v', ///< Vector type alignment FLOAT_ALIGN = 'f', ///< Floating point type alignment AGGREGATE_ALIGN = 'a', ///< Aggregate alignment STACK_ALIGN = 's' ///< Stack objects alignment }; /// Target alignment element. /// /// Stores the alignment data associated with a given alignment type (pointer, /// 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 TargetAlignElem { AlignTypeEnum AlignType : 8; //< Alignment type (AlignTypeEnum) unsigned ABIAlign; //< ABI alignment for this type/bitw unsigned PrefAlign; //< Pref. alignment for this type/bitw uint32_t TypeBitWidth; //< Type bit width /// Initializer static TargetAlignElem get(AlignTypeEnum align_type, unsigned abi_align, unsigned pref_align, uint32_t bit_width); /// Equality predicate bool operator==(const TargetAlignElem &rhs) const; }; /// TargetData - 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 TargetData : public ImmutablePass { private: bool LittleEndian; ///< Defaults to false unsigned PointerMemSize; ///< Pointer size in bytes unsigned PointerABIAlign; ///< Pointer ABI alignment unsigned PointerPrefAlign; ///< Pointer preferred alignment unsigned StackNaturalAlign; ///< Stack natural alignment 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 TargetAlignment, but for now, /// we don't. SmallVector<TargetAlignElem, 16> Alignments; /// InvalidAlignmentElem - This member is a signal that a requested alignment /// type and bit width were not found in the SmallVector. static const TargetAlignElem InvalidAlignmentElem; // 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; //! 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 TargetAlignElem reference returned by get() against /// InvalidAlignmentElem. bool validAlignment(const TargetAlignElem &align) const { return &align != &InvalidAlignmentElem; } /// Initialise a TargetData object with default values, ensure that the /// target data pass is registered. void init(); public: /// Default ctor. /// /// @note This has to exist, because this is a pass, but it should never be /// used. TargetData(); /// Constructs a TargetData from a specification string. See init(). explicit TargetData(StringRef TargetDescription) : ImmutablePass(ID) { std::string errMsg = parseSpecifier(TargetDescription, this); assert(errMsg == "" && "Invalid target data layout string."); (void)errMsg; } /// Parses a target data specification string. Returns an error message /// if the string is malformed, or the empty string on success. Optionally /// initialises a TargetData object if passed a non-null pointer. static std::string parseSpecifier(StringRef TargetDescription, TargetData* td = 0); /// Initialize target data from properties stored in the module. explicit TargetData(const Module *M); TargetData(const TargetData &TD) : ImmutablePass(ID), LittleEndian(TD.isLittleEndian()), PointerMemSize(TD.PointerMemSize), PointerABIAlign(TD.PointerABIAlign), PointerPrefAlign(TD.PointerPrefAlign), LegalIntWidths(TD.LegalIntWidths), Alignments(TD.Alignments), LayoutMap(0) { } ~TargetData(); // Not virtual, do not subclass this class /// Target endianness... bool isLittleEndian() const { return LittleEndian; } bool isBigEndian() const { return !LittleEndian; } /// getStringRepresentation - Return the string representation of the /// TargetData. 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); } /// 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; } /// Target pointer alignment unsigned getPointerABIAlignment() const { return PointerABIAlign; } /// Return target's alignment for stack-based pointers unsigned getPointerPrefAlignment() const { return PointerPrefAlign; } /// Target pointer size unsigned getPointerSize() const { return PointerMemSize; } /// Target pointer size, in bits unsigned getPointerSizeInBits() const { return 8*PointerMemSize; } /// 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. 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; /// getCallFrameTypeAlignment - Return the minimum ABI-required alignment /// for the specified type when it is part of a call frame. unsigned getCallFrameTypeAlignment(Type *Ty) 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 unsigned integer type that is the same size or /// greater to the host pointer size. /// IntegerType *getIntPtrType(LLVMContext &C) 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 TargetData 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 TargetData; // Only TargetData can create this class StructLayout(StructType *ST, const TargetData &TD); }; } // End llvm namespace #endif