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// Copyright 2017 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.
#include "src/common/globals.h"
#include "src/heap/heap.h"
#include "src/objects/heap-object.h"
#include "src/snapshot/serializer-common.h"
namespace v8 {
namespace internal {
class Deserializer;
class StartupDeserializer;
class DeserializerAllocator final {
DeserializerAllocator() = default;
void Initialize(Heap* heap) { heap_ = heap; }
// ------- Allocation Methods -------
// Methods related to memory allocation during deserialization.
Address Allocate(SnapshotSpace space, int size);
void MoveToNextChunk(SnapshotSpace space);
void SetAlignment(AllocationAlignment alignment) {
DCHECK_EQ(kWordAligned, next_alignment_);
DCHECK_LE(kWordAligned, alignment);
DCHECK_LE(alignment, kDoubleUnaligned);
next_alignment_ = static_cast<AllocationAlignment>(alignment);
void set_next_reference_is_weak(bool next_reference_is_weak) {
next_reference_is_weak_ = next_reference_is_weak;
bool GetAndClearNextReferenceIsWeak() {
bool saved = next_reference_is_weak_;
next_reference_is_weak_ = false;
return saved;
#ifdef DEBUG
bool next_reference_is_weak() const { return next_reference_is_weak_; }
HeapObject GetMap(uint32_t index);
HeapObject GetLargeObject(uint32_t index);
HeapObject GetObject(SnapshotSpace space, uint32_t chunk_index,
uint32_t chunk_offset);
// ------- Reservation Methods -------
// Methods related to memory reservations (prior to deserialization).
V8_EXPORT_PRIVATE void DecodeReservation(
const std::vector<SerializedData::Reservation>& res);
bool ReserveSpace();
bool ReservationsAreFullyUsed() const;
// ------- Misc Utility Methods -------
void RegisterDeserializedObjectsForBlackAllocation();
// Raw allocation without considering alignment.
Address AllocateRaw(SnapshotSpace space, int size);
static constexpr int kNumberOfPreallocatedSpaces =
static constexpr int kNumberOfSpaces =
// The address of the next object that will be allocated in each space.
// Each space has a number of chunks reserved by the GC, with each chunk
// fitting into a page. Deserialized objects are allocated into the
// current chunk of the target space by bumping up high water mark.
Heap::Reservation reservations_[kNumberOfSpaces];
uint32_t current_chunk_[kNumberOfPreallocatedSpaces];
Address high_water_[kNumberOfPreallocatedSpaces];
// The alignment of the next allocation.
AllocationAlignment next_alignment_ = kWordAligned;
bool next_reference_is_weak_ = false;
// All required maps are pre-allocated during reservation. {next_map_index_}
// stores the index of the next map to return from allocation.
uint32_t next_map_index_ = 0;
std::vector<Address> allocated_maps_;
// Allocated large objects are kept in this map and may be fetched later as
// back-references.
std::vector<HeapObject> deserialized_large_objects_;
Heap* heap_;
} // namespace internal
} // namespace v8