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// Copyright 2016 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/partial-serializer.h"
#include "src/snapshot/startup-serializer.h"
#include "src/api.h"
#include "src/objects-inl.h"
namespace v8 {
namespace internal {
PartialSerializer::PartialSerializer(
Isolate* isolate, StartupSerializer* startup_serializer,
v8::SerializeEmbedderFieldsCallback callback)
: Serializer(isolate),
startup_serializer_(startup_serializer),
serialize_embedder_fields_(callback),
can_be_rehashed_(true) {
InitializeCodeAddressMap();
}
PartialSerializer::~PartialSerializer() {
OutputStatistics("PartialSerializer");
}
void PartialSerializer::Serialize(Object** o, bool include_global_proxy) {
DCHECK((*o)->IsNativeContext());
Context* context = Context::cast(*o);
reference_map()->AddAttachedReference(context->global_proxy());
// The bootstrap snapshot has a code-stub context. When serializing the
// partial snapshot, it is chained into the weak context list on the isolate
// and it's next context pointer may point to the code-stub context. Clear
// it before serializing, it will get re-added to the context list
// explicitly when it's loaded.
context->set(Context::NEXT_CONTEXT_LINK,
isolate()->heap()->undefined_value());
DCHECK(!context->global_object()->IsUndefined(context->GetIsolate()));
// Reset math random cache to get fresh random numbers.
context->set_math_random_index(Smi::kZero);
context->set_math_random_cache(isolate()->heap()->undefined_value());
VisitRootPointer(Root::kPartialSnapshotCache, o);
SerializeDeferredObjects();
SerializeEmbedderFields();
Pad();
}
void PartialSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
DCHECK(!ObjectIsBytecodeHandler(obj)); // Only referenced in dispatch table.
BuiltinReferenceSerializationMode mode =
startup_serializer_->clear_function_code() ? kCanonicalizeCompileLazy
: kDefault;
if (SerializeBuiltinReference(obj, how_to_code, where_to_point, skip, mode)) {
return;
}
if (SerializeHotObject(obj, how_to_code, where_to_point, skip)) return;
int root_index = root_index_map()->Lookup(obj);
if (root_index != RootIndexMap::kInvalidRootIndex) {
PutRoot(root_index, obj, how_to_code, where_to_point, skip);
return;
}
if (SerializeBackReference(obj, how_to_code, where_to_point, skip)) return;
if (ShouldBeInThePartialSnapshotCache(obj)) {
FlushSkip(skip);
int cache_index = startup_serializer_->PartialSnapshotCacheIndex(obj);
sink_.Put(kPartialSnapshotCache + how_to_code + where_to_point,
"PartialSnapshotCache");
sink_.PutInt(cache_index, "partial_snapshot_cache_index");
return;
}
// Pointers from the partial snapshot to the objects in the startup snapshot
// should go through the root array or through the partial snapshot cache.
// If this is not the case you may have to add something to the root array.
DCHECK(!startup_serializer_->ReferenceMapContains(obj));
// All the internalized strings that the partial snapshot needs should be
// either in the root table or in the partial snapshot cache.
DCHECK(!obj->IsInternalizedString());
// Function and object templates are not context specific.
DCHECK(!obj->IsTemplateInfo());
FlushSkip(skip);
// Clear literal boilerplates and feedback.
if (obj->IsFeedbackVector()) FeedbackVector::cast(obj)->ClearSlots(isolate());
if (obj->IsJSObject()) {
JSObject* jsobj = JSObject::cast(obj);
if (jsobj->GetEmbedderFieldCount() > 0) {
DCHECK_NOT_NULL(serialize_embedder_fields_.callback);
embedder_field_holders_.push_back(jsobj);
}
}
CheckRehashability(obj);
// Object has not yet been serialized. Serialize it here.
ObjectSerializer serializer(this, obj, &sink_, how_to_code, where_to_point);
serializer.Serialize();
}
bool PartialSerializer::ShouldBeInThePartialSnapshotCache(HeapObject* o) {
// Scripts should be referred only through shared function infos. We can't
// allow them to be part of the partial snapshot because they contain a
// unique ID, and deserializing several partial snapshots containing script
// would cause dupes.
DCHECK(!o->IsScript());
return o->IsName() || o->IsSharedFunctionInfo() || o->IsHeapNumber() ||
o->IsCode() || o->IsScopeInfo() || o->IsAccessorInfo() ||
o->IsTemplateInfo() ||
o->map() ==
startup_serializer_->isolate()->heap()->fixed_cow_array_map();
}
void PartialSerializer::SerializeEmbedderFields() {
if (embedder_field_holders_.empty()) return;
DisallowHeapAllocation no_gc;
DisallowJavascriptExecution no_js(isolate());
DisallowCompilation no_compile(isolate());
DCHECK_NOT_NULL(serialize_embedder_fields_.callback);
sink_.Put(kEmbedderFieldsData, "embedder fields data");
while (!embedder_field_holders_.empty()) {
HandleScope scope(isolate());
Handle<JSObject> obj(embedder_field_holders_.back(), isolate());
embedder_field_holders_.pop_back();
SerializerReference reference = reference_map()->Lookup(*obj);
DCHECK(reference.is_back_reference());
int embedder_fields_count = obj->GetEmbedderFieldCount();
for (int i = 0; i < embedder_fields_count; i++) {
if (obj->GetEmbedderField(i)->IsHeapObject()) continue;
StartupData data = serialize_embedder_fields_.callback(
v8::Utils::ToLocal(obj), i, serialize_embedder_fields_.data);
sink_.Put(kNewObject + reference.space(), "embedder field holder");
PutBackReference(*obj, reference);
sink_.PutInt(i, "embedder field index");
sink_.PutInt(data.raw_size, "embedder fields data size");
sink_.PutRaw(reinterpret_cast<const byte*>(data.data), data.raw_size,
"embedder fields data");
delete[] data.data;
}
}
sink_.Put(kSynchronize, "Finished with embedder fields data");
}
void PartialSerializer::CheckRehashability(HeapObject* obj) {
if (!can_be_rehashed_) return;
if (!obj->NeedsRehashing()) return;
if (obj->CanBeRehashed()) return;
can_be_rehashed_ = false;
}
} // namespace internal
} // namespace v8
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