llvm/clang/lib/AST/ByteCode/Pointer.h

//===--- Pointer.h - Types for the constexpr VM -----------------*- 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
//
//===----------------------------------------------------------------------===//
//
// Defines the classes responsible for pointer tracking.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_INTERP_POINTER_H
#define LLVM_CLANG_AST_INTERP_POINTER_H

#include "Descriptor.h"
#include "FunctionPointer.h"
#include "InterpBlock.h"
#include "clang/AST/ComparisonCategories.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/Expr.h"
#include "llvm/Support/raw_ostream.h"

namespace clang {
namespace interp {
class Block;
class DeadBlock;
class Pointer;
class Context;
template <unsigned A, bool B> class Integral;
enum PrimType : unsigned;

class Pointer;
inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Pointer &P);

struct BlockPointer { … };

struct IntPointer { … };

enum class Storage { … };

/// A pointer to a memory block, live or dead.
///
/// This object can be allocated into interpreter stack frames. If pointing to
/// a live block, it is a link in the chain of pointers pointing to the block.
///
/// In the simplest form, a Pointer has a Block* (the pointee) and both Base
/// and Offset are 0, which means it will point to raw data.
///
/// The Base field is used to access metadata about the data. For primitive
/// arrays, the Base is followed by an InitMap. In a variety of cases, the
/// Base is preceded by an InlineDescriptor, which is used to track the
/// initialization state, among other things.
///
/// The Offset field is used to access the actual data. In other words, the
/// data the pointer decribes can be found at
/// Pointee->rawData() + Pointer.Offset.
///
///
/// Pointee                      Offset
/// │                              │
/// │                              │
/// ▼                              ▼
/// ┌───────┬────────────┬─────────┬────────────────────────────┐
/// │ Block │ InlineDesc │ InitMap │ Actual Data                │
/// └───────┴────────────┴─────────┴────────────────────────────┘
///                      ▲
///                      │
///                      │
///                     Base
class Pointer { … };

inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Pointer &P) { … }

} // namespace interp
} // namespace clang

#endif