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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.
#include "src/snapshot/serializer-deserializer.h"
#include "src/objects/foreign-inl.h"
#include "src/objects/objects-inl.h"
namespace v8 {
namespace internal {
// The startup object cache is terminated by undefined. We visit the context
// snapshot...
// - during deserialization to populate it.
// - during normal GC to keep its content alive.
// - not during serialization. The context serializer adds to it explicitly.
DISABLE_CFI_PERF
void SerializerDeserializer::Iterate(Isolate* isolate, RootVisitor* visitor) {
std::vector<Object>* cache = isolate->startup_object_cache();
for (size_t i = 0;; ++i) {
// Extend the array ready to get a value when deserializing.
if (cache->size() <= i) cache->push_back(Smi::zero());
// During deserialization, the visitor populates the startup object cache
// and eventually terminates the cache with undefined.
visitor->VisitRootPointer(Root::kStartupObjectCache, nullptr,
FullObjectSlot(&cache->at(i)));
if (cache->at(i).IsUndefined(isolate)) break;
}
}
bool SerializerDeserializer::CanBeDeferred(HeapObject o) {
// ArrayBuffer instances are serialized by first re-assigning a index
// to the backing store field, then serializing the object, and then
// storing the actual backing store address again (and the same for the
// ArrayBufferExtension). If serialization of the object itself is deferred,
// the real backing store address is written into the snapshot, which cannot
// be processed when deserializing.
return !o.IsString() && !o.IsScript() && !o.IsJSTypedArray() &&
!o.IsJSArrayBuffer();
}
void SerializerDeserializer::RestoreExternalReferenceRedirectors(
Isolate* isolate, const std::vector<AccessorInfo>& accessor_infos) {
// Restore wiped accessor infos.
for (AccessorInfo info : accessor_infos) {
Foreign::cast(info.js_getter())
.set_foreign_address(isolate, info.redirected_getter());
}
}
void SerializerDeserializer::RestoreExternalReferenceRedirectors(
Isolate* isolate, const std::vector<CallHandlerInfo>& call_handler_infos) {
for (CallHandlerInfo info : call_handler_infos) {
Foreign::cast(info.js_callback())
.set_foreign_address(isolate, info.redirected_callback());
}
}
} // namespace internal
} // namespace v8
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