chromium/v8/src/heap/read-only-spaces.h

// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_HEAP_READ_ONLY_SPACES_H_
#define V8_HEAP_READ_ONLY_SPACES_H_

#include <memory>
#include <optional>
#include <utility>

#include "include/v8-platform.h"
#include "src/base/macros.h"
#include "src/common/globals.h"
#include "src/heap/allocation-result.h"
#include "src/heap/allocation-stats.h"
#include "src/heap/base-space.h"
#include "src/heap/heap-verifier.h"
#include "src/heap/list.h"
#include "src/heap/memory-chunk-metadata.h"
#include "src/heap/mutable-page-metadata.h"

namespace v8 {
namespace internal {

class MemoryAllocator;
class ReadOnlyHeap;
class SnapshotByteSource;

class ReadOnlyPageMetadata : public MemoryChunkMetadata { … };

// -----------------------------------------------------------------------------
// Artifacts used to construct a new SharedReadOnlySpace
class ReadOnlyArtifacts { … };

// -----------------------------------------------------------------------------
// Artifacts used to construct a new SharedReadOnlySpace when pointer
// compression is disabled and so there is a single ReadOnlySpace with one set
// of pages shared between all Isolates.
class SingleCopyReadOnlyArtifacts : public ReadOnlyArtifacts { … };

// -----------------------------------------------------------------------------
// Artifacts used to construct a new SharedReadOnlySpace when pointer
// compression is enabled and so there is a ReadOnlySpace for each Isolate with
// with its own set of pages mapped from the canonical set stored here.
class PointerCompressedReadOnlyArtifacts : public ReadOnlyArtifacts { … };

// -----------------------------------------------------------------------------
// Read Only space for all Immortal Immovable and Immutable objects
class ReadOnlySpace : public BaseSpace { … };

class SharedReadOnlySpace : public ReadOnlySpace { … };

}  // namespace internal

namespace base {
// Define special hash function for page pointers, to be used with std data
// structures, e.g. std::unordered_set<ReadOnlyPageMetadata*,
// base::hash<ReadOnlyPageMetadata*>
template <>
struct hash<i::ReadOnlyPageMetadata*> : hash<i::MemoryChunkMetadata*> { … };
template <>
struct hash<const i::ReadOnlyPageMetadata*>
    : hash<const i::MemoryChunkMetadata*> { … };
}  // namespace base

}  // namespace v8

#endif  // V8_HEAP_READ_ONLY_SPACES_H_