// Copyright 2016 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/snapshot/serializer.h"
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#include "src/assembler-inl.h"
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#include "src/heap/heap.h"
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#include "src/interpreter/interpreter.h"
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#include "src/objects/code.h"
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#include "src/objects/js-array-buffer-inl.h"
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#include "src/objects/js-array-inl.h"
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#include "src/objects/map.h"
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#include "src/snapshot/builtin-serializer-allocator.h"
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#include "src/snapshot/natives.h"
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#include "src/snapshot/snapshot.h"
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namespace v8 {
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namespace internal {
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template <class AllocatorT>
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Serializer<AllocatorT>::Serializer(Isolate* isolate)
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: isolate_(isolate),
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external_reference_encoder_(isolate),
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root_index_map_(isolate),
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allocator_(this) {
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#ifdef OBJECT_PRINT
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if (FLAG_serialization_statistics) {
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for (int space = 0; space < LAST_SPACE; ++space) {
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instance_type_count_[space] = NewArray<int>(kInstanceTypes);
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instance_type_size_[space] = NewArray<size_t>(kInstanceTypes);
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for (int i = 0; i < kInstanceTypes; i++) {
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instance_type_count_[space][i] = 0;
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instance_type_size_[space][i] = 0;
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}
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}
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} else {
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for (int space = 0; space < LAST_SPACE; ++space) {
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instance_type_count_[space] = nullptr;
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instance_type_size_[space] = nullptr;
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}
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}
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#endif // OBJECT_PRINT
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}
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template <class AllocatorT>
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Serializer<AllocatorT>::~Serializer() {
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if (code_address_map_ != nullptr) delete code_address_map_;
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#ifdef OBJECT_PRINT
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for (int space = 0; space < LAST_SPACE; ++space) {
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if (instance_type_count_[space] != nullptr) {
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DeleteArray(instance_type_count_[space]);
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DeleteArray(instance_type_size_[space]);
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}
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}
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#endif // OBJECT_PRINT
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}
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#ifdef OBJECT_PRINT
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template <class AllocatorT>
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void Serializer<AllocatorT>::CountInstanceType(Map* map, int size,
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AllocationSpace space) {
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int instance_type = map->instance_type();
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instance_type_count_[space][instance_type]++;
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instance_type_size_[space][instance_type] += size;
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}
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#endif // OBJECT_PRINT
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template <class AllocatorT>
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void Serializer<AllocatorT>::OutputStatistics(const char* name) {
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if (!FLAG_serialization_statistics) return;
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PrintF("%s:\n", name);
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allocator()->OutputStatistics();
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#ifdef OBJECT_PRINT
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PrintF(" Instance types (count and bytes):\n");
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#define PRINT_INSTANCE_TYPE(Name) \
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for (int space = 0; space < LAST_SPACE; ++space) { \
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if (instance_type_count_[space][Name]) { \
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PrintF("%10d %10" PRIuS " %-10s %s\n", \
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instance_type_count_[space][Name], \
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instance_type_size_[space][Name], \
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AllocationSpaceName(static_cast<AllocationSpace>(space)), #Name); \
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} \
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}
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INSTANCE_TYPE_LIST(PRINT_INSTANCE_TYPE)
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#undef PRINT_INSTANCE_TYPE
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PrintF("\n");
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#endif // OBJECT_PRINT
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::SerializeDeferredObjects() {
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while (!deferred_objects_.empty()) {
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HeapObject* obj = deferred_objects_.back();
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deferred_objects_.pop_back();
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ObjectSerializer obj_serializer(this, obj, &sink_, kPlain, kStartOfObject);
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obj_serializer.SerializeDeferred();
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}
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sink_.Put(kSynchronize, "Finished with deferred objects");
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}
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template <class AllocatorT>
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bool Serializer<AllocatorT>::MustBeDeferred(HeapObject* object) {
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return false;
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::VisitRootPointers(Root root,
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const char* description,
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Object** start, Object** end) {
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// Builtins and bytecode handlers are serialized in a separate pass by the
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// BuiltinSerializer.
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if (root == Root::kBuiltins || root == Root::kDispatchTable) return;
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for (Object** current = start; current < end; current++) {
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SerializeRootObject(*current);
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}
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::SerializeRootObject(Object* object) {
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if (object->IsSmi()) {
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PutSmi(Smi::cast(object));
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} else {
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SerializeObject(HeapObject::cast(object), kPlain, kStartOfObject, 0);
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}
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}
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#ifdef DEBUG
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template <class AllocatorT>
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void Serializer<AllocatorT>::PrintStack() {
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for (const auto o : stack_) {
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o->Print();
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PrintF("\n");
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}
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}
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#endif // DEBUG
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template <class AllocatorT>
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bool Serializer<AllocatorT>::SerializeHotObject(HeapObject* obj,
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HowToCode how_to_code,
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WhereToPoint where_to_point,
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int skip) {
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if (how_to_code != kPlain || where_to_point != kStartOfObject) return false;
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// Encode a reference to a hot object by its index in the working set.
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int index = hot_objects_.Find(obj);
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if (index == HotObjectsList::kNotFound) return false;
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DCHECK(index >= 0 && index < kNumberOfHotObjects);
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if (FLAG_trace_serializer) {
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PrintF(" Encoding hot object %d:", index);
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obj->ShortPrint();
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PrintF("\n");
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}
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if (skip != 0) {
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sink_.Put(kHotObjectWithSkip + index, "HotObjectWithSkip");
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sink_.PutInt(skip, "HotObjectSkipDistance");
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} else {
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sink_.Put(kHotObject + index, "HotObject");
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}
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return true;
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}
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template <class AllocatorT>
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bool Serializer<AllocatorT>::SerializeBackReference(HeapObject* obj,
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HowToCode how_to_code,
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WhereToPoint where_to_point,
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int skip) {
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SerializerReference reference = reference_map_.LookupReference(obj);
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if (!reference.is_valid()) return false;
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// Encode the location of an already deserialized object in order to write
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// its location into a later object. We can encode the location as an
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// offset fromthe start of the deserialized objects or as an offset
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// backwards from thecurrent allocation pointer.
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if (reference.is_attached_reference()) {
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FlushSkip(skip);
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if (FLAG_trace_serializer) {
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PrintF(" Encoding attached reference %d\n",
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reference.attached_reference_index());
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}
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PutAttachedReference(reference, how_to_code, where_to_point);
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} else {
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DCHECK(reference.is_back_reference());
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if (FLAG_trace_serializer) {
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PrintF(" Encoding back reference to: ");
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obj->ShortPrint();
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PrintF("\n");
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}
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PutAlignmentPrefix(obj);
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AllocationSpace space = reference.space();
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if (skip == 0) {
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sink_.Put(kBackref + how_to_code + where_to_point + space, "BackRef");
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} else {
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sink_.Put(kBackrefWithSkip + how_to_code + where_to_point + space,
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"BackRefWithSkip");
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sink_.PutInt(skip, "BackRefSkipDistance");
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}
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PutBackReference(obj, reference);
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}
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return true;
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}
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template <class AllocatorT>
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bool Serializer<AllocatorT>::SerializeBuiltinReference(
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HeapObject* obj, HowToCode how_to_code, WhereToPoint where_to_point,
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int skip) {
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if (!obj->IsCode()) return false;
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Code* code = Code::cast(obj);
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int builtin_index = code->builtin_index();
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if (builtin_index < 0) return false;
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DCHECK((how_to_code == kPlain && where_to_point == kStartOfObject) ||
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(how_to_code == kFromCode));
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DCHECK_LT(builtin_index, Builtins::builtin_count);
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DCHECK_LE(0, builtin_index);
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if (FLAG_trace_serializer) {
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PrintF(" Encoding builtin reference: %s\n",
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isolate()->builtins()->name(builtin_index));
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}
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FlushSkip(skip);
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sink_.Put(kBuiltin + how_to_code + where_to_point, "Builtin");
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sink_.PutInt(builtin_index, "builtin_index");
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return true;
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}
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template <class AllocatorT>
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bool Serializer<AllocatorT>::ObjectIsBytecodeHandler(HeapObject* obj) const {
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if (!obj->IsCode()) return false;
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Code* code = Code::cast(obj);
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if (isolate()->heap()->IsDeserializeLazyHandler(code)) return false;
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return (code->kind() == Code::BYTECODE_HANDLER);
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::PutRoot(
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int root_index, HeapObject* object,
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SerializerDeserializer::HowToCode how_to_code,
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SerializerDeserializer::WhereToPoint where_to_point, int skip) {
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if (FLAG_trace_serializer) {
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PrintF(" Encoding root %d:", root_index);
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object->ShortPrint();
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PrintF("\n");
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}
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// Assert that the first 32 root array items are a conscious choice. They are
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// chosen so that the most common ones can be encoded more efficiently.
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STATIC_ASSERT(Heap::kArgumentsMarkerRootIndex ==
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kNumberOfRootArrayConstants - 1);
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if (how_to_code == kPlain && where_to_point == kStartOfObject &&
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root_index < kNumberOfRootArrayConstants && !Heap::InNewSpace(object)) {
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if (skip == 0) {
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sink_.Put(kRootArrayConstants + root_index, "RootConstant");
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} else {
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sink_.Put(kRootArrayConstantsWithSkip + root_index, "RootConstant");
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sink_.PutInt(skip, "SkipInPutRoot");
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}
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} else {
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FlushSkip(skip);
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sink_.Put(kRootArray + how_to_code + where_to_point, "RootSerialization");
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sink_.PutInt(root_index, "root_index");
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hot_objects_.Add(object);
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}
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::PutSmi(Smi* smi) {
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sink_.Put(kOnePointerRawData, "Smi");
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byte* bytes = reinterpret_cast<byte*>(&smi);
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for (int i = 0; i < kPointerSize; i++) sink_.Put(bytes[i], "Byte");
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::PutBackReference(HeapObject* object,
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SerializerReference reference) {
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DCHECK(allocator()->BackReferenceIsAlreadyAllocated(reference));
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switch (reference.space()) {
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case MAP_SPACE:
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sink_.PutInt(reference.map_index(), "BackRefMapIndex");
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break;
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case LO_SPACE:
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sink_.PutInt(reference.large_object_index(), "BackRefLargeObjectIndex");
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break;
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default:
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sink_.PutInt(reference.chunk_index(), "BackRefChunkIndex");
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sink_.PutInt(reference.chunk_offset(), "BackRefChunkOffset");
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break;
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}
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hot_objects_.Add(object);
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::PutAttachedReference(SerializerReference reference,
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HowToCode how_to_code,
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WhereToPoint where_to_point) {
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DCHECK(reference.is_attached_reference());
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DCHECK((how_to_code == kPlain && where_to_point == kStartOfObject) ||
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(how_to_code == kFromCode && where_to_point == kStartOfObject) ||
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(how_to_code == kFromCode && where_to_point == kInnerPointer));
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sink_.Put(kAttachedReference + how_to_code + where_to_point, "AttachedRef");
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sink_.PutInt(reference.attached_reference_index(), "AttachedRefIndex");
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}
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template <class AllocatorT>
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int Serializer<AllocatorT>::PutAlignmentPrefix(HeapObject* object) {
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AllocationAlignment alignment = HeapObject::RequiredAlignment(object->map());
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if (alignment != kWordAligned) {
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DCHECK(1 <= alignment && alignment <= 3);
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byte prefix = (kAlignmentPrefix - 1) + alignment;
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sink_.Put(prefix, "Alignment");
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return Heap::GetMaximumFillToAlign(alignment);
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}
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return 0;
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::PutNextChunk(int space) {
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sink_.Put(kNextChunk, "NextChunk");
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sink_.Put(space, "NextChunkSpace");
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::Pad() {
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// The non-branching GetInt will read up to 3 bytes too far, so we need
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// to pad the snapshot to make sure we don't read over the end.
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for (unsigned i = 0; i < sizeof(int32_t) - 1; i++) {
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sink_.Put(kNop, "Padding");
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}
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// Pad up to pointer size for checksum.
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while (!IsAligned(sink_.Position(), kPointerAlignment)) {
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sink_.Put(kNop, "Padding");
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}
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::InitializeCodeAddressMap() {
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isolate_->InitializeLoggingAndCounters();
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code_address_map_ = new CodeAddressMap(isolate_);
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}
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template <class AllocatorT>
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Code* Serializer<AllocatorT>::CopyCode(Code* code) {
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code_buffer_.clear(); // Clear buffer without deleting backing store.
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int size = code->CodeSize();
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code_buffer_.insert(code_buffer_.end(),
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reinterpret_cast<byte*>(code->address()),
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reinterpret_cast<byte*>(code->address() + size));
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return Code::cast(HeapObject::FromAddress(
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reinterpret_cast<Address>(&code_buffer_.front())));
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::ObjectSerializer::SerializePrologue(
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AllocationSpace space, int size, Map* map) {
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if (serializer_->code_address_map_) {
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const char* code_name =
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serializer_->code_address_map_->Lookup(object_->address());
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LOG(serializer_->isolate_,
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CodeNameEvent(object_->address(), sink_->Position(), code_name));
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}
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SerializerReference back_reference;
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if (space == LO_SPACE) {
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sink_->Put(kNewObject + reference_representation_ + space,
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"NewLargeObject");
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sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
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if (object_->IsCode()) {
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sink_->Put(EXECUTABLE, "executable large object");
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} else {
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sink_->Put(NOT_EXECUTABLE, "not executable large object");
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}
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back_reference = serializer_->allocator()->AllocateLargeObject(size);
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} else if (space == MAP_SPACE) {
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DCHECK_EQ(Map::kSize, size);
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back_reference = serializer_->allocator()->AllocateMap();
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sink_->Put(kNewObject + reference_representation_ + space, "NewMap");
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// This is redundant, but we include it anyways.
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sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
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} else {
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int fill = serializer_->PutAlignmentPrefix(object_);
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back_reference = serializer_->allocator()->Allocate(space, size + fill);
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sink_->Put(kNewObject + reference_representation_ + space, "NewObject");
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sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
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}
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#ifdef OBJECT_PRINT
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if (FLAG_serialization_statistics) {
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serializer_->CountInstanceType(map, size, space);
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}
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#endif // OBJECT_PRINT
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// Mark this object as already serialized.
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serializer_->reference_map()->Add(object_, back_reference);
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// Serialize the map (first word of the object).
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serializer_->SerializeObject(map, kPlain, kStartOfObject, 0);
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}
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template <class AllocatorT>
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int32_t Serializer<AllocatorT>::ObjectSerializer::SerializeBackingStore(
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void* backing_store, int32_t byte_length) {
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SerializerReference reference =
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serializer_->reference_map()->LookupReference(backing_store);
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// Serialize the off-heap backing store.
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if (!reference.is_valid()) {
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sink_->Put(kOffHeapBackingStore, "Off-heap backing store");
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sink_->PutInt(byte_length, "length");
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sink_->PutRaw(static_cast<byte*>(backing_store), byte_length,
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"BackingStore");
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reference = serializer_->allocator()->AllocateOffHeapBackingStore();
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// Mark this backing store as already serialized.
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serializer_->reference_map()->Add(backing_store, reference);
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}
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return static_cast<int32_t>(reference.off_heap_backing_store_index());
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::ObjectSerializer::SerializeJSTypedArray() {
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JSTypedArray* typed_array = JSTypedArray::cast(object_);
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FixedTypedArrayBase* elements =
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FixedTypedArrayBase::cast(typed_array->elements());
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if (!typed_array->WasNeutered()) {
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if (!typed_array->is_on_heap()) {
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// Explicitly serialize the backing store now.
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JSArrayBuffer* buffer = JSArrayBuffer::cast(typed_array->buffer());
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CHECK(buffer->byte_length()->IsSmi());
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CHECK(typed_array->byte_offset()->IsSmi());
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int32_t byte_length = NumberToInt32(buffer->byte_length());
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int32_t byte_offset = NumberToInt32(typed_array->byte_offset());
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// We need to calculate the backing store from the external pointer
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// because the ArrayBuffer may already have been serialized.
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void* backing_store = reinterpret_cast<void*>(
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reinterpret_cast<intptr_t>(elements->external_pointer()) -
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byte_offset);
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int32_t ref = SerializeBackingStore(backing_store, byte_length);
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// The external_pointer is the backing_store + typed_array->byte_offset.
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// To properly share the buffer, we set the backing store ref here. On
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// deserialization we re-add the byte_offset to external_pointer.
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elements->set_external_pointer(Smi::FromInt(ref));
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}
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} else {
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// When a JSArrayBuffer is neutered, the FixedTypedArray that points to the
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// same backing store does not know anything about it. This fixup step finds
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// neutered TypedArrays and clears the values in the FixedTypedArray so that
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// we don't try to serialize the now invalid backing store.
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elements->set_external_pointer(Smi::kZero);
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elements->set_length(0);
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}
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SerializeObject();
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::ObjectSerializer::SerializeJSArrayBuffer() {
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JSArrayBuffer* buffer = JSArrayBuffer::cast(object_);
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void* backing_store = buffer->backing_store();
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// We cannot store byte_length larger than Smi range in the snapshot.
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// Attempt to make sure that NumberToInt32 produces something sensible.
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CHECK(buffer->byte_length()->IsSmi());
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int32_t byte_length = NumberToInt32(buffer->byte_length());
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// The embedder-allocated backing store only exists for the off-heap case.
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if (backing_store != nullptr) {
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int32_t ref = SerializeBackingStore(backing_store, byte_length);
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buffer->set_backing_store(Smi::FromInt(ref));
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}
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SerializeObject();
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buffer->set_backing_store(backing_store);
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}
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template <class AllocatorT>
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void Serializer<AllocatorT>::ObjectSerializer::SerializeExternalString() {
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Heap* heap = serializer_->isolate()->heap();
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// For external strings with known resources, we replace the resource field
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// with the encoded external reference, which we restore upon deserialize.
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// for native native source code strings, we replace the resource field
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// with the native source id.
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// For the rest we serialize them to look like ordinary sequential strings.
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if (object_->map() != ReadOnlyRoots(heap).native_source_string_map()) {
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ExternalString* string = ExternalString::cast(object_);
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Address resource = string->resource_as_address();
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ExternalReferenceEncoder::Value reference;
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if (serializer_->external_reference_encoder_.TryEncode(resource).To(
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&reference)) {
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DCHECK(reference.is_from_api());
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string->set_uint32_as_resource(reference.index());
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SerializeObject();
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string->set_address_as_resource(resource);
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} else {
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SerializeExternalStringAsSequentialString();
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}
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} else {
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ExternalOneByteString* string = ExternalOneByteString::cast(object_);
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DCHECK(string->is_short());
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const NativesExternalStringResource* resource =
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reinterpret_cast<const NativesExternalStringResource*>(
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string->resource());
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// Replace the resource field with the type and index of the native source.
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string->set_resource(resource->EncodeForSerialization());
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SerializeObject();
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// Restore the resource field.
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string->set_resource(resource);
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}
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}
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template <class AllocatorT>
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void Serializer<
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AllocatorT>::ObjectSerializer::SerializeExternalStringAsSequentialString() {
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// Instead of serializing this as an external string, we serialize
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// an imaginary sequential string with the same content.
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ReadOnlyRoots roots(serializer_->isolate());
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DCHECK(object_->IsExternalString());
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DCHECK(object_->map() != roots.native_source_string_map());
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ExternalString* string = ExternalString::cast(object_);
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int length = string->length();
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Map* map;
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int content_size;
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int allocation_size;
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const byte* resource;
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// Find the map and size for the imaginary sequential string.
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bool internalized = object_->IsInternalizedString();
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if (object_->IsExternalOneByteString()) {
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map = internalized ? roots.one_byte_internalized_string_map()
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: roots.one_byte_string_map();
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allocation_size = SeqOneByteString::SizeFor(length);
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content_size = length * kCharSize;
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resource = reinterpret_cast<const byte*>(
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ExternalOneByteString::cast(string)->resource()->data());
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} else {
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map = internalized ? roots.internalized_string_map() : roots.string_map();
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allocation_size = SeqTwoByteString::SizeFor(length);
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content_size = length * kShortSize;
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resource = reinterpret_cast<const byte*>(
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ExternalTwoByteString::cast(string)->resource()->data());
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}
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AllocationSpace space =
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(allocation_size > kMaxRegularHeapObjectSize) ? LO_SPACE : OLD_SPACE;
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SerializePrologue(space, allocation_size, map);
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// Output the rest of the imaginary string.
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int bytes_to_output = allocation_size - HeapObject::kHeaderSize;
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// Output raw data header. Do not bother with common raw length cases here.
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sink_->Put(kVariableRawData, "RawDataForString");
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sink_->PutInt(bytes_to_output, "length");
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// Serialize string header (except for map).
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uint8_t* string_start = reinterpret_cast<uint8_t*>(string->address());
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for (int i = HeapObject::kHeaderSize; i < SeqString::kHeaderSize; i++) {
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sink_->PutSection(string_start[i], "StringHeader");
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}
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// Serialize string content.
|
sink_->PutRaw(resource, content_size, "StringContent");
|
|
// Since the allocation size is rounded up to object alignment, there
|
// maybe left-over bytes that need to be padded.
|
int padding_size = allocation_size - SeqString::kHeaderSize - content_size;
|
DCHECK(0 <= padding_size && padding_size < kObjectAlignment);
|
for (int i = 0; i < padding_size; i++) sink_->PutSection(0, "StringPadding");
|
}
|
|
// Clear and later restore the next link in the weak cell or allocation site.
|
// TODO(all): replace this with proper iteration of weak slots in serializer.
|
class UnlinkWeakNextScope {
|
public:
|
explicit UnlinkWeakNextScope(Heap* heap, HeapObject* object)
|
: object_(nullptr) {
|
if (object->IsAllocationSite()) {
|
object_ = object;
|
next_ = AllocationSite::cast(object)->weak_next();
|
AllocationSite::cast(object)->set_weak_next(
|
ReadOnlyRoots(heap).undefined_value());
|
}
|
}
|
|
~UnlinkWeakNextScope() {
|
if (object_ != nullptr) {
|
AllocationSite::cast(object_)->set_weak_next(next_,
|
UPDATE_WEAK_WRITE_BARRIER);
|
}
|
}
|
|
private:
|
HeapObject* object_;
|
Object* next_;
|
DisallowHeapAllocation no_gc_;
|
};
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::Serialize() {
|
if (FLAG_trace_serializer) {
|
PrintF(" Encoding heap object: ");
|
object_->ShortPrint();
|
PrintF("\n");
|
}
|
|
if (object_->IsExternalString()) {
|
SerializeExternalString();
|
return;
|
} else if (!serializer_->isolate()->heap()->InReadOnlySpace(object_)) {
|
// Only clear padding for strings outside RO_SPACE. RO_SPACE should have
|
// been cleared elsewhere.
|
if (object_->IsSeqOneByteString()) {
|
// Clear padding bytes at the end. Done here to avoid having to do this
|
// at allocation sites in generated code.
|
SeqOneByteString::cast(object_)->clear_padding();
|
} else if (object_->IsSeqTwoByteString()) {
|
SeqTwoByteString::cast(object_)->clear_padding();
|
}
|
}
|
if (object_->IsJSTypedArray()) {
|
SerializeJSTypedArray();
|
return;
|
}
|
if (object_->IsJSArrayBuffer()) {
|
SerializeJSArrayBuffer();
|
return;
|
}
|
|
// We don't expect fillers.
|
DCHECK(!object_->IsFiller());
|
|
if (object_->IsScript()) {
|
// Clear cached line ends.
|
Object* undefined = ReadOnlyRoots(serializer_->isolate()).undefined_value();
|
Script::cast(object_)->set_line_ends(undefined);
|
}
|
|
SerializeObject();
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::SerializeObject() {
|
int size = object_->Size();
|
Map* map = object_->map();
|
AllocationSpace space =
|
MemoryChunk::FromAddress(object_->address())->owner()->identity();
|
DCHECK(space != NEW_LO_SPACE);
|
SerializePrologue(space, size, map);
|
|
// Serialize the rest of the object.
|
CHECK_EQ(0, bytes_processed_so_far_);
|
bytes_processed_so_far_ = kPointerSize;
|
|
RecursionScope recursion(serializer_);
|
// Objects that are immediately post processed during deserialization
|
// cannot be deferred, since post processing requires the object content.
|
if ((recursion.ExceedsMaximum() && CanBeDeferred(object_)) ||
|
serializer_->MustBeDeferred(object_)) {
|
serializer_->QueueDeferredObject(object_);
|
sink_->Put(kDeferred, "Deferring object content");
|
return;
|
}
|
|
SerializeContent(map, size);
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::SerializeDeferred() {
|
if (FLAG_trace_serializer) {
|
PrintF(" Encoding deferred heap object: ");
|
object_->ShortPrint();
|
PrintF("\n");
|
}
|
|
int size = object_->Size();
|
Map* map = object_->map();
|
SerializerReference back_reference =
|
serializer_->reference_map()->LookupReference(object_);
|
DCHECK(back_reference.is_back_reference());
|
|
// Serialize the rest of the object.
|
CHECK_EQ(0, bytes_processed_so_far_);
|
bytes_processed_so_far_ = kPointerSize;
|
|
serializer_->PutAlignmentPrefix(object_);
|
sink_->Put(kNewObject + back_reference.space(), "deferred object");
|
serializer_->PutBackReference(object_, back_reference);
|
sink_->PutInt(size >> kPointerSizeLog2, "deferred object size");
|
|
SerializeContent(map, size);
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::SerializeContent(Map* map,
|
int size) {
|
UnlinkWeakNextScope unlink_weak_next(serializer_->isolate()->heap(), object_);
|
if (object_->IsCode()) {
|
// For code objects, output raw bytes first.
|
OutputCode(size);
|
// Then iterate references via reloc info.
|
object_->IterateBody(map, size, this);
|
// Finally skip to the end.
|
serializer_->FlushSkip(SkipTo(object_->address() + size));
|
} else {
|
// For other objects, iterate references first.
|
object_->IterateBody(map, size, this);
|
// Then output data payload, if any.
|
OutputRawData(object_->address() + size);
|
}
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitPointers(HeapObject* host,
|
Object** start,
|
Object** end) {
|
VisitPointers(host, reinterpret_cast<MaybeObject**>(start),
|
reinterpret_cast<MaybeObject**>(end));
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitPointers(
|
HeapObject* host, MaybeObject** start, MaybeObject** end) {
|
MaybeObject** current = start;
|
while (current < end) {
|
while (current < end &&
|
((*current)->IsSmi() || (*current)->IsClearedWeakHeapObject())) {
|
current++;
|
}
|
if (current < end) {
|
OutputRawData(reinterpret_cast<Address>(current));
|
}
|
HeapObject* current_contents;
|
HeapObjectReferenceType reference_type;
|
while (current < end && (*current)->ToStrongOrWeakHeapObject(
|
¤t_contents, &reference_type)) {
|
int root_index = serializer_->root_index_map()->Lookup(current_contents);
|
// Repeats are not subject to the write barrier so we can only use
|
// immortal immovable root members. They are never in new space.
|
if (current != start && root_index != RootIndexMap::kInvalidRootIndex &&
|
Heap::RootIsImmortalImmovable(root_index) &&
|
*current == current[-1]) {
|
DCHECK_EQ(reference_type, HeapObjectReferenceType::STRONG);
|
DCHECK(!Heap::InNewSpace(current_contents));
|
int repeat_count = 1;
|
while (¤t[repeat_count] < end - 1 &&
|
current[repeat_count] == *current) {
|
repeat_count++;
|
}
|
current += repeat_count;
|
bytes_processed_so_far_ += repeat_count * kPointerSize;
|
if (repeat_count > kNumberOfFixedRepeat) {
|
sink_->Put(kVariableRepeat, "VariableRepeat");
|
sink_->PutInt(repeat_count, "repeat count");
|
} else {
|
sink_->Put(kFixedRepeatStart + repeat_count, "FixedRepeat");
|
}
|
} else {
|
if (reference_type == HeapObjectReferenceType::WEAK) {
|
sink_->Put(kWeakPrefix, "WeakReference");
|
}
|
serializer_->SerializeObject(current_contents, kPlain, kStartOfObject,
|
0);
|
bytes_processed_so_far_ += kPointerSize;
|
current++;
|
}
|
}
|
}
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitEmbeddedPointer(
|
Code* host, RelocInfo* rinfo) {
|
int skip = SkipTo(rinfo->target_address_address());
|
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
|
Object* object = rinfo->target_object();
|
serializer_->SerializeObject(HeapObject::cast(object), how_to_code,
|
kStartOfObject, skip);
|
bytes_processed_so_far_ += rinfo->target_address_size();
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitExternalReference(
|
Foreign* host, Address* p) {
|
int skip = SkipTo(reinterpret_cast<Address>(p));
|
Address target = *p;
|
auto encoded_reference = serializer_->EncodeExternalReference(target);
|
if (encoded_reference.is_from_api()) {
|
sink_->Put(kApiReference, "ApiRef");
|
} else {
|
sink_->Put(kExternalReference + kPlain + kStartOfObject, "ExternalRef");
|
}
|
sink_->PutInt(skip, "SkipB4ExternalRef");
|
sink_->PutInt(encoded_reference.index(), "reference index");
|
bytes_processed_so_far_ += kPointerSize;
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitExternalReference(
|
Code* host, RelocInfo* rinfo) {
|
int skip = SkipTo(rinfo->target_address_address());
|
Address target = rinfo->target_external_reference();
|
auto encoded_reference = serializer_->EncodeExternalReference(target);
|
if (encoded_reference.is_from_api()) {
|
DCHECK(!rinfo->IsCodedSpecially());
|
sink_->Put(kApiReference, "ApiRef");
|
} else {
|
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
|
sink_->Put(kExternalReference + how_to_code + kStartOfObject,
|
"ExternalRef");
|
}
|
sink_->PutInt(skip, "SkipB4ExternalRef");
|
DCHECK_NE(target, kNullAddress); // Code does not reference null.
|
sink_->PutInt(encoded_reference.index(), "reference index");
|
bytes_processed_so_far_ += rinfo->target_address_size();
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitInternalReference(
|
Code* host, RelocInfo* rinfo) {
|
// We do not use skip from last patched pc to find the pc to patch, since
|
// target_address_address may not return addresses in ascending order when
|
// used for internal references. External references may be stored at the
|
// end of the code in the constant pool, whereas internal references are
|
// inline. That would cause the skip to be negative. Instead, we store the
|
// offset from code entry.
|
Address entry = Code::cast(object_)->entry();
|
DCHECK_GE(rinfo->target_internal_reference_address(), entry);
|
uintptr_t pc_offset = rinfo->target_internal_reference_address() - entry;
|
DCHECK_LE(pc_offset, Code::cast(object_)->raw_instruction_size());
|
DCHECK_GE(rinfo->target_internal_reference(), entry);
|
uintptr_t target_offset = rinfo->target_internal_reference() - entry;
|
DCHECK_LE(target_offset, Code::cast(object_)->raw_instruction_size());
|
sink_->Put(rinfo->rmode() == RelocInfo::INTERNAL_REFERENCE
|
? kInternalReference
|
: kInternalReferenceEncoded,
|
"InternalRef");
|
sink_->PutInt(pc_offset, "internal ref address");
|
sink_->PutInt(target_offset, "internal ref value");
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitRuntimeEntry(
|
Code* host, RelocInfo* rinfo) {
|
int skip = SkipTo(rinfo->target_address_address());
|
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
|
Address target = rinfo->target_address();
|
auto encoded_reference = serializer_->EncodeExternalReference(target);
|
DCHECK(!encoded_reference.is_from_api());
|
sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
|
sink_->PutInt(skip, "SkipB4ExternalRef");
|
sink_->PutInt(encoded_reference.index(), "reference index");
|
bytes_processed_so_far_ += rinfo->target_address_size();
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitOffHeapTarget(
|
Code* host, RelocInfo* rinfo) {
|
DCHECK(FLAG_embedded_builtins);
|
{
|
STATIC_ASSERT(EmbeddedData::kTableSize == Builtins::builtin_count);
|
CHECK(Builtins::IsIsolateIndependentBuiltin(host));
|
Address addr = rinfo->target_off_heap_target();
|
CHECK_NE(kNullAddress, addr);
|
CHECK_NOT_NULL(
|
InstructionStream::TryLookupCode(serializer_->isolate(), addr));
|
}
|
|
int skip = SkipTo(rinfo->target_address_address());
|
sink_->Put(kOffHeapTarget, "OffHeapTarget");
|
sink_->PutInt(skip, "SkipB4OffHeapTarget");
|
sink_->PutInt(host->builtin_index(), "builtin index");
|
bytes_processed_so_far_ += rinfo->target_address_size();
|
}
|
|
namespace {
|
class CompareRelocInfo {
|
public:
|
bool operator()(RelocInfo x, RelocInfo y) {
|
// Everything that does not use target_address_address will compare equal.
|
Address x_num = 0;
|
Address y_num = 0;
|
if (HasTargetAddressAddress(x.rmode())) {
|
x_num = x.target_address_address();
|
}
|
if (HasTargetAddressAddress(y.rmode())) {
|
y_num = y.target_address_address();
|
}
|
return x_num > y_num;
|
}
|
|
private:
|
static bool HasTargetAddressAddress(RelocInfo::Mode mode) {
|
return RelocInfo::IsEmbeddedObject(mode) || RelocInfo::IsCodeTarget(mode) ||
|
RelocInfo::IsExternalReference(mode) ||
|
RelocInfo::IsRuntimeEntry(mode);
|
}
|
};
|
} // namespace
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitRelocInfo(
|
RelocIterator* it) {
|
std::priority_queue<RelocInfo, std::vector<RelocInfo>, CompareRelocInfo>
|
reloc_queue;
|
for (; !it->done(); it->next()) {
|
reloc_queue.push(*it->rinfo());
|
}
|
while (!reloc_queue.empty()) {
|
RelocInfo rinfo = reloc_queue.top();
|
reloc_queue.pop();
|
rinfo.Visit(this);
|
}
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::VisitCodeTarget(
|
Code* host, RelocInfo* rinfo) {
|
int skip = SkipTo(rinfo->target_address_address());
|
Code* object = Code::GetCodeFromTargetAddress(rinfo->target_address());
|
serializer_->SerializeObject(object, kFromCode, kInnerPointer, skip);
|
bytes_processed_so_far_ += rinfo->target_address_size();
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::OutputRawData(Address up_to) {
|
Address object_start = object_->address();
|
int base = bytes_processed_so_far_;
|
int up_to_offset = static_cast<int>(up_to - object_start);
|
int to_skip = up_to_offset - bytes_processed_so_far_;
|
int bytes_to_output = to_skip;
|
bytes_processed_so_far_ += to_skip;
|
DCHECK_GE(to_skip, 0);
|
if (bytes_to_output != 0) {
|
DCHECK(to_skip == bytes_to_output);
|
if (IsAligned(bytes_to_output, kPointerAlignment) &&
|
bytes_to_output <= kNumberOfFixedRawData * kPointerSize) {
|
int size_in_words = bytes_to_output >> kPointerSizeLog2;
|
sink_->PutSection(kFixedRawDataStart + size_in_words, "FixedRawData");
|
} else {
|
sink_->Put(kVariableRawData, "VariableRawData");
|
sink_->PutInt(bytes_to_output, "length");
|
}
|
#ifdef MEMORY_SANITIZER
|
// Check that we do not serialize uninitialized memory.
|
__msan_check_mem_is_initialized(
|
reinterpret_cast<void*>(object_start + base), bytes_to_output);
|
#endif // MEMORY_SANITIZER
|
if (object_->IsBytecodeArray()) {
|
// The code age byte can be changed concurrently by GC.
|
const int bytes_to_age_byte = BytecodeArray::kBytecodeAgeOffset - base;
|
if (0 <= bytes_to_age_byte && bytes_to_age_byte < bytes_to_output) {
|
sink_->PutRaw(reinterpret_cast<byte*>(object_start + base),
|
bytes_to_age_byte, "Bytes");
|
byte bytecode_age = BytecodeArray::kNoAgeBytecodeAge;
|
sink_->PutRaw(&bytecode_age, 1, "Bytes");
|
const int bytes_written = bytes_to_age_byte + 1;
|
sink_->PutRaw(
|
reinterpret_cast<byte*>(object_start + base + bytes_written),
|
bytes_to_output - bytes_written, "Bytes");
|
} else {
|
sink_->PutRaw(reinterpret_cast<byte*>(object_start + base),
|
bytes_to_output, "Bytes");
|
}
|
} else {
|
sink_->PutRaw(reinterpret_cast<byte*>(object_start + base),
|
bytes_to_output, "Bytes");
|
}
|
}
|
}
|
|
template <class AllocatorT>
|
int Serializer<AllocatorT>::ObjectSerializer::SkipTo(Address to) {
|
Address object_start = object_->address();
|
int up_to_offset = static_cast<int>(to - object_start);
|
int to_skip = up_to_offset - bytes_processed_so_far_;
|
bytes_processed_so_far_ += to_skip;
|
// This assert will fail if the reloc info gives us the target_address_address
|
// locations in a non-ascending order. We make sure this doesn't happen by
|
// sorting the relocation info.
|
DCHECK_GE(to_skip, 0);
|
return to_skip;
|
}
|
|
template <class AllocatorT>
|
void Serializer<AllocatorT>::ObjectSerializer::OutputCode(int size) {
|
DCHECK_EQ(kPointerSize, bytes_processed_so_far_);
|
Code* code = Code::cast(object_);
|
// To make snapshots reproducible, we make a copy of the code object
|
// and wipe all pointers in the copy, which we then serialize.
|
code = serializer_->CopyCode(code);
|
int mode_mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET) |
|
RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
|
RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
|
RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
|
RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED) |
|
RelocInfo::ModeMask(RelocInfo::OFF_HEAP_TARGET) |
|
RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
|
for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
|
RelocInfo* rinfo = it.rinfo();
|
rinfo->WipeOut();
|
}
|
// We need to wipe out the header fields *after* wiping out the
|
// relocations, because some of these fields are needed for the latter.
|
code->WipeOutHeader();
|
|
Address start = code->address() + Code::kDataStart;
|
int bytes_to_output = size - Code::kDataStart;
|
|
sink_->Put(kVariableRawCode, "VariableRawCode");
|
sink_->PutInt(bytes_to_output, "length");
|
|
#ifdef MEMORY_SANITIZER
|
// Check that we do not serialize uninitialized memory.
|
__msan_check_mem_is_initialized(reinterpret_cast<void*>(start),
|
bytes_to_output);
|
#endif // MEMORY_SANITIZER
|
sink_->PutRaw(reinterpret_cast<byte*>(start), bytes_to_output, "Code");
|
}
|
|
// Explicit instantiation.
|
template class Serializer<BuiltinSerializerAllocator>;
|
template class Serializer<DefaultSerializerAllocator>;
|
|
} // namespace internal
|
} // namespace v8
|
