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llvm-for-llvmta/include/llvm/IR/DataLayout.h

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//===- 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/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/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Alignment.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 TypeByteWidth;
uint32_t AddressSpace;
uint32_t IndexWidth;
/// Initializer
static PointerAlignElem get(uint32_t AddressSpace, Align ABIAlign,
Align PrefAlign, uint32_t TypeByteWidth,
uint32_t IndexWidth);
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_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 setPointerAlignment(uint32_t AddrSpace, Align ABIAlign, Align PrefAlign,
uint32_t TypeByteWidth, uint32_t IndexWidth);
/// 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 {
for (unsigned LegalIntWidth : LegalIntWidths)
if (LegalIntWidth == Width)
return true;
return false;
}
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_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_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
/// FIXME: The defaults need to be removed once all of
/// the backends/clients are updated.
unsigned getPointerSize(unsigned AS = 0) const;
/// Returns the maximum pointer size over all address spaces.
unsigned getMaxPointerSize() const;
// Index size used for address calculation.
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 getPointerSize(AS) * 8;
}
/// Returns the maximum pointer size over all address spaces.
unsigned getMaxPointerSizeInBits() const {
return getMaxPointerSize() * 8;
}
/// Size in bits of index used for address calculation in getelementptr.
unsigned getIndexSizeInBits(unsigned AS) const {
return getIndexSize(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;
/// 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 { (BaseSize.getKnownMinSize() + 7) / 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), getABITypeAlignment(Ty));
}
/// 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.
unsigned 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.
unsigned 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;
/// 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;
/// Returns the preferred alignment of the specified global.
///
/// This includes an explicitly requested alignment (if the global has one).
LLVM_ATTRIBUTE_DEPRECATED(
inline unsigned getPreferredAlignment(const GlobalVariable *GV) const,
"Use getPreferredAlign instead") {
return getPreferredAlign(GV).value();
}
/// Returns the preferred alignment of the specified global, returned
/// in log form.
///
/// This includes an explicitly requested alignment (if the global has one).
LLVM_ATTRIBUTE_DEPRECATED(
inline unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const,
"Inline where needed") {
return Log2(getPreferredAlign(GV));
}
};
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 {
uint64_t StructSize;
Align StructAlignment;
unsigned IsPadded : 1;
unsigned NumElements : 31;
uint64_t MemberOffsets[1]; // variable sized array!
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;
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 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()).getFixedSize();
return TypeSize(MinBits, EltCnt.isScalable());
}
default:
llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
}
}
} // end namespace llvm
#endif // LLVM_IR_DATALAYOUT_H
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