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

//===-- InterpBlock.h - Allocated blocks for the interpreter -*- 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 describing allocated blocks.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_INTERP_BLOCK_H
#define LLVM_CLANG_AST_INTERP_BLOCK_H

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

namespace clang {
namespace interp {
class Block;
class DeadBlock;
class InterpState;
class Pointer;
enum PrimType : unsigned;

/// A memory block, either on the stack or in the heap.
///
/// The storage described by the block is immediately followed by
/// optional metadata, which is followed by the actual data.
///
/// Block*        rawData()                  data()
/// │               │                         │
/// │               │                         │
/// ▼               ▼                         ▼
/// ┌───────────────┬─────────────────────────┬─────────────────┐
/// │ Block         │ Metadata                │ Data            │
/// │ sizeof(Block) │ Desc->getMetadataSize() │ Desc->getSize() │
/// └───────────────┴─────────────────────────┴─────────────────┘
///
/// Desc->getAllocSize() describes the size after the Block, i.e.
/// the data size and the metadata size.
///
class Block final { … };

/// Descriptor for a dead block.
///
/// Dead blocks are chained in a double-linked list to deallocate them
/// whenever pointers become dead.
class DeadBlock final { … };

} // namespace interp
} // namespace clang

#endif