chromium/v8/src/heap/new-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_NEW_SPACES_H_
#define V8_HEAP_NEW_SPACES_H_

#include <atomic>
#include <memory>
#include <numeric>
#include <optional>

#include "include/v8-internal.h"
#include "src/base/logging.h"
#include "src/base/macros.h"
#include "src/base/platform/mutex.h"
#include "src/common/globals.h"
#include "src/heap/allocation-observer.h"
#include "src/heap/heap-verifier.h"
#include "src/heap/heap.h"
#include "src/heap/paged-spaces.h"
#include "src/heap/spaces.h"
#include "src/objects/heap-object.h"

namespace v8 {
namespace internal {

class Heap;
class MutablePageMetadata;
class SemiSpaceNewSpace;

enum SemiSpaceId { … };

// -----------------------------------------------------------------------------
// SemiSpace in young generation
//
// A SemiSpace is a contiguous chunk of memory holding page-like memory chunks.
// The mark-compact collector  uses the memory of the first page in the from
// space as a marking stack when tracing live objects.
class SemiSpace final : public Space { … };

// A SemiSpaceObjectIterator is an ObjectIterator that iterates over the active
// semispace of the heap's new space.
class SemiSpaceObjectIterator : public ObjectIterator { … };

class NewSpace : NON_EXPORTED_BASE(public SpaceWithLinearArea) { … };

// -----------------------------------------------------------------------------
// The young generation space.
//
// The new space consists of a contiguous pair of semispaces.  It simply
// forwards most functions to the appropriate semispace.

class V8_EXPORT_PRIVATE SemiSpaceNewSpace final : public NewSpace { … };

// -----------------------------------------------------------------------------
// PagedNewSpace

class V8_EXPORT_PRIVATE PagedSpaceForNewSpace final : public PagedSpaceBase { … };

// TODO(v8:12612): PagedNewSpace is a bridge between the NewSpace interface and
// the PagedSpaceForNewSpace implementation. Once we settle on a single new
// space implementation, we can merge these 3 classes into 1.
class V8_EXPORT_PRIVATE PagedNewSpace final : public NewSpace { … };

// For contiguous spaces, top should be in the space (or at the end) and limit
// should be the end of the space.
#define DCHECK_SEMISPACE_ALLOCATION_TOP(top, space) …

}  // namespace internal
}  // namespace v8

#endif  // V8_HEAP_NEW_SPACES_H_