//===- 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 <cassert>
 
#include <cstdint>
 
#include <string>
 
 
 
// 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 {
 
  INVALID_ALIGN = 0,
 
  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 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 {
 
  /// Alignment type from \c AlignTypeEnum
 
  unsigned AlignType : 8;
 
  unsigned TypeBitWidth : 24;
 
  Align ABIAlign;
 
  Align PrefAlign;
 
 
 
  static LayoutAlignElem get(AlignTypeEnum align_type, Align abi_align,
 
                             Align pref_align, uint32_t bit_width);
 
 
 
  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<unsigned char, 8> LegalIntWidths;
 
 
 
  /// Primitive type alignment data. This is sorted by type and bit
 
  /// width during construction.
 
  using AlignmentsTy = SmallVector<LayoutAlignElem, 16>;
 
  AlignmentsTy Alignments;
 
 
 
  AlignmentsTy::const_iterator
 
  findAlignmentLowerBound(AlignTypeEnum AlignType, uint32_t BitWidth) const {
 
    return const_cast<DataLayout *>(this)->findAlignmentLowerBound(AlignType,
 
                                                                   BitWidth);
 
  }
 
 
 
  AlignmentsTy::iterator
 
  findAlignmentLowerBound(AlignTypeEnum AlignType, uint32_t BitWidth);
 
 
 
  /// The string representation used to create this DataLayout
 
  std::string StringRepresentation;
 
 
 
  using PointersTy = SmallVector<PointerAlignElem, 8>;
 
  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<unsigned, 8> NonIntegralAddressSpaces;
 
 
 
  /// Attempts to set the alignment of the given type. Returns an error
 
  /// description on failure.
 
  Error setAlignment(AlignTypeEnum align_type, Align abi_align,
 
                     Align pref_align, uint32_t bit_width);
 
 
 
  /// 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;
 
    Alignments = DL.Alignments;
 
    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<DataLayout> 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; }
 
 
 
  /// 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<unsigned> getNonIntegralAddressSpaces() const {
 
    return NonIntegralAddressSpaces;
 
  }
 
 
 
  bool isNonIntegralAddressSpace(unsigned AddrSpace) const {
 
    ArrayRef<unsigned> 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<PointerType>(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.
 
  /// FIXME: Deprecate this function once migration to Align is over.
 
  LLVM_DEPRECATED("use getABITypeAlign instead", "getABITypeAlign")
 
  uint64_t getABITypeAlignment(Type *Ty) const;
 
 
 
  /// 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
 
  /// `getABITypeAlignment(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.
 
  /// 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<Value *> 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<APInt> 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<APInt> 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<DataLayout *>(P);
 
}
 
 
 
inline LLVMTargetDataRef wrap(const DataLayout *P) {
 
  return reinterpret_cast<LLVMTargetDataRef>(const_cast<DataLayout *>(P));
 
}
 
 
 
/// Used to lazily calculate structure layout information for a target machine,
 
/// based on the DataLayout structure.
 
class StructLayout final : public TrailingObjects<StructLayout, uint64_t> {
 
  uint64_t StructSize;
 
  Align StructAlignment;
 
  unsigned IsPadded : 1;
 
  unsigned NumElements : 31;
 
 
 
public:
 
  uint64_t getSizeInBytes() const { return StructSize; }
 
 
 
  uint64_t 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 Offset) const;
 
 
 
  MutableArrayRef<uint64_t> getMemberOffsets() {
 
    return llvm::MutableArrayRef(getTrailingObjects<uint64_t>(),
 
                                     NumElements);
 
  }
 
 
 
  ArrayRef<uint64_t> getMemberOffsets() const {
 
    return llvm::ArrayRef(getTrailingObjects<uint64_t>(), NumElements);
 
  }
 
 
 
  uint64_t getElementOffset(unsigned Idx) const {
 
    assert(Idx < NumElements && "Invalid element idx!");
 
    return getMemberOffsets()[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);
 
 
 
  size_t numTrailingObjects(OverloadToken<uint64_t>) 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::Fixed(getPointerSizeInBits(0));
 
  case Type::PointerTyID:
 
    return TypeSize::Fixed(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 TypeSize::Fixed(
 
                        getStructLayout(cast<StructType>(Ty))->getSizeInBits());
 
  case Type::IntegerTyID:
 
    return TypeSize::Fixed(Ty->getIntegerBitWidth());
 
  case Type::HalfTyID:
 
  case Type::BFloatTyID:
 
    return TypeSize::Fixed(16);
 
  case Type::FloatTyID:
 
    return TypeSize::Fixed(32);
 
  case Type::DoubleTyID:
 
  case Type::X86_MMXTyID:
 
    return TypeSize::Fixed(64);
 
  case Type::PPC_FP128TyID:
 
  case Type::FP128TyID:
 
    return TypeSize::Fixed(128);
 
  case Type::X86_AMXTyID:
 
    return TypeSize::Fixed(8192);
 
  // In memory objects this is always aligned to a higher boundary, but
 
  // only 80 bits contain information.
 
  case Type::X86_FP80TyID:
 
    return TypeSize::Fixed(80);
 
  case Type::FixedVectorTyID:
 
  case Type::ScalableVectorTyID: {
 
    VectorType *VTy = cast<VectorType>(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<TargetExtType>(Ty)->getLayoutType();
 
    return getTypeSizeInBits(LayoutTy);
 
  }
 
  default:
 
    llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
 
  }
 
}
 
 
 
} // end namespace llvm
 
 
 
#endif // LLVM_IR_DATALAYOUT_H