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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.
#ifndef V8_SNAPSHOT_SERIALIZER_ALLOCATOR_H_
#define V8_SNAPSHOT_SERIALIZER_ALLOCATOR_H_
#include "src/snapshot/serializer-common.h"
namespace v8 {
namespace internal {
class Serializer;
class SerializerAllocator final {
public:
explicit SerializerAllocator(Serializer* serializer);
SerializerReference Allocate(SnapshotSpace space, uint32_t size);
SerializerReference AllocateMap();
SerializerReference AllocateLargeObject(uint32_t size);
SerializerReference AllocateOffHeapBackingStore();
void UseCustomChunkSize(uint32_t chunk_size);
#ifdef DEBUG
bool BackReferenceIsAlreadyAllocated(
SerializerReference back_reference) const;
#endif
std::vector<SerializedData::Reservation> EncodeReservations() const;
void OutputStatistics();
private:
// We try to not exceed this size for every chunk. We will not succeed for
// larger objects though.
uint32_t TargetChunkSize(SnapshotSpace space);
static constexpr int kNumberOfPreallocatedSpaces =
static_cast<int>(SnapshotSpace::kNumberOfPreallocatedSpaces);
static constexpr int kNumberOfSpaces =
static_cast<int>(SnapshotSpace::kNumberOfSpaces);
// Objects from the same space are put into chunks for bulk-allocation
// when deserializing. We have to make sure that each chunk fits into a
// page. So we track the chunk size in pending_chunk_ of a space, but
// when it exceeds a page, we complete the current chunk and start a new one.
uint32_t pending_chunk_[kNumberOfPreallocatedSpaces];
std::vector<uint32_t> completed_chunks_[kNumberOfPreallocatedSpaces];
// Number of maps that we need to allocate.
uint32_t num_maps_ = 0;
// We map serialized large objects to indexes for back-referencing.
uint32_t large_objects_total_size_ = 0;
uint32_t seen_large_objects_index_ = 0;
// Used to keep track of the off-heap backing stores used by TypedArrays/
// ArrayBuffers. Note that the index begins at 1 and not 0, because when a
// TypedArray has an on-heap backing store, the backing_store pointer in the
// corresponding ArrayBuffer will be null, which makes it indistinguishable
// from index 0.
uint32_t seen_backing_stores_index_ = 1;
uint32_t custom_chunk_size_ = 0;
// The current serializer.
Serializer* const serializer_;
DISALLOW_COPY_AND_ASSIGN(SerializerAllocator);
};
} // namespace internal
} // namespace v8
#endif // V8_SNAPSHOT_SERIALIZER_ALLOCATOR_H_
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