llvm/llvm/include/llvm/IR/DataLayout.h

//===- 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.
LLVMTargetDataRef;

namespace llvm {

class GlobalVariable;
class LLVMContext;
class StructLayout;
class Triple;
class Value;

// 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.

/// 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 { … };

inline DataLayout *unwrap(LLVMTargetDataRef P) { … }

inline LLVMTargetDataRef wrap(const DataLayout *P) { … }

/// Used to lazily calculate structure layout information for a target machine,
/// based on the DataLayout structure.
class StructLayout final : public TrailingObjects<StructLayout, TypeSize> { … };

// 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 { … }

} // end namespace llvm

#endif // LLVM_IR_DATALAYOUT_H