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// 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_MEMORY_CHUNK_LAYOUT_H_
#define V8_HEAP_MEMORY_CHUNK_LAYOUT_H_
#include "src/base/platform/mutex.h"
#include "src/common/globals.h"
#include "src/heap/base/active-system-pages.h"
#include "src/heap/list.h"
#include "src/heap/marking.h"
#include "src/heap/progress-bar.h"
#include "src/heap/slot-set.h"
namespace v8 {
namespace internal {
class MarkingBitmap;
class FreeListCategory;
class Heap;
class TypedSlotsSet;
class SlotSet;
enum RememberedSetType {
OLD_TO_NEW,
OLD_TO_NEW_BACKGROUND,
OLD_TO_OLD,
OLD_TO_SHARED,
OLD_TO_CODE,
NUMBER_OF_REMEMBERED_SET_TYPES
};
using ActiveSystemPages = ::heap::base::ActiveSystemPages;
class V8_EXPORT_PRIVATE MemoryChunkLayout {
public:
static constexpr int kNumSets = NUMBER_OF_REMEMBERED_SET_TYPES;
static constexpr int kNumTypes =
static_cast<int>(ExternalBackingStoreType::kNumValues);
static constexpr int kMemoryChunkAlignment = sizeof(size_t);
#define FIELD(Type, Name) \
k##Name##Offset, k##Name##End = k##Name##Offset + sizeof(Type) - 1
enum Header {
// BasicMemoryChunk fields:
FIELD(size_t, Size),
FIELD(uintptr_t, Flags),
FIELD(Heap*, Heap),
FIELD(Address, AreaStart),
FIELD(Address, AreaEnd),
FIELD(size_t, AllocatedBytes),
FIELD(size_t, WastedMemory),
FIELD(std::atomic<intptr_t>, HighWaterMark),
FIELD(Address, Owner),
FIELD(VirtualMemory, Reservation),
// MemoryChunk fields:
FIELD(SlotSet* [kNumSets], SlotSet),
FIELD(TypedSlotsSet* [kNumSets], TypedSlotSet),
FIELD(ProgressBar, ProgressBar),
FIELD(std::atomic<intptr_t>, LiveByteCount),
FIELD(base::Mutex*, Mutex),
FIELD(base::SharedMutex*, SharedMutex),
FIELD(base::Mutex*, PageProtectionChangeMutex),
FIELD(std::atomic<intptr_t>, ConcurrentSweeping),
FIELD(std::atomic<size_t>[kNumTypes], ExternalBackingStoreBytes),
FIELD(heap::ListNode<MemoryChunk>, ListNode),
FIELD(FreeListCategory**, Categories),
FIELD(PossiblyEmptyBuckets, PossiblyEmptyBuckets),
FIELD(ActiveSystemPages*, ActiveSystemPages),
FIELD(size_t, AllocatedLabSize),
FIELD(size_t, AgeInNewSpace),
FIELD(MarkingBitmap, MarkingBitmap),
kEndOfMarkingBitmap,
kMemoryChunkHeaderSize =
kEndOfMarkingBitmap +
((kEndOfMarkingBitmap % kMemoryChunkAlignment) == 0
? 0
: kMemoryChunkAlignment -
(kEndOfMarkingBitmap % kMemoryChunkAlignment)),
kMemoryChunkHeaderStart = kSlotSetOffset,
kBasicMemoryChunkHeaderSize = kMemoryChunkHeaderStart,
kBasicMemoryChunkHeaderStart = 0,
};
#undef FIELD
static size_t CodePageGuardStartOffset();
static size_t CodePageGuardSize();
// Code pages have padding on the first page for code alignment, so the
// ObjectStartOffset will not be page aligned.
static intptr_t ObjectPageOffsetInCodePage();
static intptr_t ObjectStartOffsetInCodePage();
static intptr_t ObjectEndOffsetInCodePage();
static size_t AllocatableMemoryInCodePage();
static intptr_t ObjectStartOffsetInDataPage();
static size_t AllocatableMemoryInDataPage();
static intptr_t ObjectStartOffsetInReadOnlyPage();
static size_t AllocatableMemoryInReadOnlyPage();
static size_t ObjectStartOffsetInMemoryChunk(AllocationSpace space);
static size_t AllocatableMemoryInMemoryChunk(AllocationSpace space);
static int MaxRegularCodeObjectSize();
static_assert(kMemoryChunkHeaderSize % alignof(size_t) == 0);
};
} // namespace internal
} // namespace v8
#endif // V8_HEAP_MEMORY_CHUNK_LAYOUT_H_
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