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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/snapshot/context-deserializer.h"
#include "src/api/api-inl.h"
#include "src/heap/heap-inl.h"
#include "src/objects/slots.h"
#include "src/snapshot/snapshot.h"
namespace v8 {
namespace internal {
MaybeHandle<Context> ContextDeserializer::DeserializeContext(
Isolate* isolate, const SnapshotData* data, bool can_rehash,
Handle<JSGlobalProxy> global_proxy,
v8::DeserializeEmbedderFieldsCallback embedder_fields_deserializer) {
ContextDeserializer d(data);
d.SetRehashability(can_rehash);
MaybeHandle<Object> maybe_result =
d.Deserialize(isolate, global_proxy, embedder_fields_deserializer);
Handle<Object> result;
return maybe_result.ToHandle(&result) ? Handle<Context>::cast(result)
: MaybeHandle<Context>();
}
MaybeHandle<Object> ContextDeserializer::Deserialize(
Isolate* isolate, Handle<JSGlobalProxy> global_proxy,
v8::DeserializeEmbedderFieldsCallback embedder_fields_deserializer) {
Initialize(isolate);
if (!allocator()->ReserveSpace()) {
V8::FatalProcessOutOfMemory(isolate, "ContextDeserializer");
}
// Replace serialized references to the global proxy and its map with the
// given global proxy and its map.
AddAttachedObject(global_proxy);
AddAttachedObject(handle(global_proxy->map(), isolate));
Handle<Object> result;
{
DisallowHeapAllocation no_gc;
// Keep track of the code space start and end pointers in case new
// code objects were unserialized
CodeSpace* code_space = isolate->heap()->code_space();
Address start_address = code_space->top();
Object root;
VisitRootPointer(Root::kStartupObjectCache, nullptr, FullObjectSlot(&root));
DeserializeDeferredObjects();
DeserializeEmbedderFields(embedder_fields_deserializer);
allocator()->RegisterDeserializedObjectsForBlackAllocation();
// There's no code deserialized here. If this assert fires then that's
// changed and logging should be added to notify the profiler et al of the
// new code, which also has to be flushed from instruction cache.
CHECK_EQ(start_address, code_space->top());
if (FLAG_rehash_snapshot && can_rehash()) Rehash();
LogNewMapEvents();
result = handle(root, isolate);
}
SetupOffHeapArrayBufferBackingStores();
return result;
}
void ContextDeserializer::SetupOffHeapArrayBufferBackingStores() {
for (Handle<JSArrayBuffer> buffer : new_off_heap_array_buffers()) {
uint32_t store_index = buffer->GetBackingStoreRefForDeserialization();
auto bs = backing_store(store_index);
SharedFlag shared =
bs && bs->is_shared() ? SharedFlag::kShared : SharedFlag::kNotShared;
buffer->Setup(shared, bs);
}
}
void ContextDeserializer::DeserializeEmbedderFields(
v8::DeserializeEmbedderFieldsCallback embedder_fields_deserializer) {
if (!source()->HasMore() || source()->Get() != kEmbedderFieldsData) return;
DisallowHeapAllocation no_gc;
DisallowJavascriptExecution no_js(isolate());
DisallowCompilation no_compile(isolate());
DCHECK_NOT_NULL(embedder_fields_deserializer.callback);
for (int code = source()->Get(); code != kSynchronize;
code = source()->Get()) {
HandleScope scope(isolate());
int space = code & kSpaceMask;
DCHECK_LE(space, kNumberOfSpaces);
DCHECK_EQ(code - space, kNewObject);
Handle<JSObject> obj(JSObject::cast(GetBackReferencedObject(
static_cast<SnapshotSpace>(space))),
isolate());
int index = source()->GetInt();
int size = source()->GetInt();
// TODO(yangguo,jgruber): Turn this into a reusable shared buffer.
byte* data = new byte[size];
source()->CopyRaw(data, size);
embedder_fields_deserializer.callback(v8::Utils::ToLocal(obj), index,
{reinterpret_cast<char*>(data), size},
embedder_fields_deserializer.data);
delete[] data;
}
}
} // namespace internal
} // namespace v8
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