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

//===--- Descriptor.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 descriptors which characterise allocations.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_INTERP_DESCRIPTOR_H
#define LLVM_CLANG_AST_INTERP_DESCRIPTOR_H

#include "PrimType.h"
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"

namespace clang {
namespace interp {
class Block;
class Record;
class SourceInfo;
struct InitMap;
struct Descriptor;
enum PrimType : unsigned;

DeclTy;
InitMapPtr;

/// Invoked whenever a block is created. The constructor method fills in the
/// inline descriptors of all fields and array elements. It also initializes
/// all the fields which contain non-trivial types.
BlockCtorFn;

/// Invoked when a block is destroyed. Invokes the destructors of all
/// non-trivial nested fields of arrays and records.
BlockDtorFn;

/// Invoked when a block with pointers referencing it goes out of scope. Such
/// blocks are persisted: the move function copies all inline descriptors and
/// non-trivial fields, as existing pointers might need to reference those
/// descriptors. Data is not copied since it cannot be legally read.
BlockMoveFn;

enum class GlobalInitState { … };

/// Descriptor used for global variables.
struct alignas(void *) GlobalInlineDescriptor { … };
static_assert …;

/// Inline descriptor embedded in structures and arrays.
///
/// Such descriptors precede all composite array elements and structure fields.
/// If the base of a pointer is not zero, the base points to the end of this
/// structure. The offset field is used to traverse the pointer chain up
/// to the root structure which allocated the object.
struct InlineDescriptor { … };
static_assert …;

/// Describes a memory block created by an allocation site.
struct Descriptor final { … };

/// Bitfield tracking the initialisation status of elements of primitive arrays.
struct InitMap final { … };

} // namespace interp
} // namespace clang

#endif