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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/startup-serializer.h"
#include "src/execution/v8threads.h"
#include "src/handles/global-handles-inl.h"
#include "src/heap/heap-inl.h"
#include "src/heap/read-only-heap.h"
#include "src/objects/contexts.h"
#include "src/objects/objects-inl.h"
#include "src/objects/slots.h"
#include "src/snapshot/read-only-serializer.h"
#include "src/snapshot/shared-heap-serializer.h"
namespace v8 {
namespace internal {
namespace {
// The isolate roots may not point at context-specific objects during
// serialization.
class V8_NODISCARD SanitizeIsolateScope final {
public:
SanitizeIsolateScope(Isolate* isolate, bool allow_active_isolate_for_testing,
const DisallowGarbageCollection& no_gc)
: isolate_(isolate),
feedback_vectors_for_profiling_tools_(
isolate->heap()->feedback_vectors_for_profiling_tools()),
detached_contexts_(isolate->heap()->detached_contexts()) {
#ifdef DEBUG
if (!allow_active_isolate_for_testing) {
// These should already be empty when creating a real snapshot.
DCHECK_EQ(feedback_vectors_for_profiling_tools_,
ReadOnlyRoots(isolate).undefined_value());
DCHECK_EQ(detached_contexts_,
ReadOnlyRoots(isolate).empty_weak_array_list());
}
#endif
isolate->SetFeedbackVectorsForProfilingTools(
ReadOnlyRoots(isolate).undefined_value());
isolate->heap()->SetDetachedContexts(
ReadOnlyRoots(isolate).empty_weak_array_list());
}
~SanitizeIsolateScope() {
// Restore saved fields.
isolate_->SetFeedbackVectorsForProfilingTools(
feedback_vectors_for_profiling_tools_);
isolate_->heap()->SetDetachedContexts(detached_contexts_);
}
private:
Isolate* isolate_;
const Tagged<Object> feedback_vectors_for_profiling_tools_;
const Tagged<WeakArrayList> detached_contexts_;
};
} // namespace
StartupSerializer::StartupSerializer(
Isolate* isolate, Snapshot::SerializerFlags flags,
SharedHeapSerializer* shared_heap_serializer)
: RootsSerializer(isolate, flags, RootIndex::kFirstStrongRoot),
shared_heap_serializer_(shared_heap_serializer),
accessor_infos_(isolate->heap()),
call_handler_infos_(isolate->heap()) {
InitializeCodeAddressMap();
}
StartupSerializer::~StartupSerializer() {
for (Handle<AccessorInfo> info : accessor_infos_) {
RestoreExternalReferenceRedirector(isolate(), *info);
}
for (Handle<CallHandlerInfo> info : call_handler_infos_) {
RestoreExternalReferenceRedirector(isolate(), *info);
}
OutputStatistics("StartupSerializer");
}
void StartupSerializer::SerializeObjectImpl(Handle<HeapObject> obj,
SlotType slot_type) {
PtrComprCageBase cage_base(isolate());
#ifdef DEBUG
if (IsJSFunction(*obj, cage_base)) {
v8::base::OS::PrintError("Reference stack:\n");
PrintStack(std::cerr);
Print(*obj, std::cerr);
FATAL(
"JSFunction should be added through the context snapshot instead of "
"the isolate snapshot");
}
#endif // DEBUG
{
DisallowGarbageCollection no_gc;
Tagged<HeapObject> raw = *obj;
DCHECK(!IsInstructionStream(raw));
if (SerializeHotObject(raw)) return;
if (IsRootAndHasBeenSerialized(raw) && SerializeRoot(raw)) return;
}
if (SerializeReadOnlyObjectReference(*obj, &sink_)) return;
if (SerializeUsingSharedHeapObjectCache(&sink_, obj)) return;
if (SerializeBackReference(*obj)) return;
if (USE_SIMULATOR_BOOL && IsAccessorInfo(*obj, cage_base)) {
// Wipe external reference redirects in the accessor info.
Handle<AccessorInfo> info = Handle<AccessorInfo>::cast(obj);
info->remove_getter_redirection(isolate());
accessor_infos_.Push(*info);
} else if (USE_SIMULATOR_BOOL && IsCallHandlerInfo(*obj, cage_base)) {
Handle<CallHandlerInfo> info = Handle<CallHandlerInfo>::cast(obj);
info->remove_callback_redirection(isolate());
call_handler_infos_.Push(*info);
} else if (IsScript(*obj, cage_base) &&
Handle<Script>::cast(obj)->IsUserJavaScript()) {
Handle<Script>::cast(obj)->set_context_data(
ReadOnlyRoots(isolate()).uninitialized_symbol());
} else if (IsSharedFunctionInfo(*obj, cage_base)) {
// Clear inferred name for native functions.
Handle<SharedFunctionInfo> shared = Handle<SharedFunctionInfo>::cast(obj);
if (!shared->IsSubjectToDebugging() && shared->HasUncompiledData()) {
shared->uncompiled_data()->set_inferred_name(
ReadOnlyRoots(isolate()).empty_string());
}
}
CheckRehashability(*obj);
// Object has not yet been serialized. Serialize it here.
DCHECK(!ReadOnlyHeap::Contains(*obj));
ObjectSerializer object_serializer(this, obj, &sink_);
object_serializer.Serialize(slot_type);
}
void StartupSerializer::SerializeWeakReferencesAndDeferred() {
// This comes right after serialization of the context snapshot, where we
// add entries to the startup object cache of the startup snapshot. Add
// one entry with 'undefined' to terminate the startup object cache.
Tagged<Object> undefined = ReadOnlyRoots(isolate()).undefined_value();
VisitRootPointer(Root::kStartupObjectCache, nullptr,
FullObjectSlot(&undefined));
isolate()->heap()->IterateWeakRoots(
this, base::EnumSet<SkipRoot>{SkipRoot::kUnserializable});
SerializeDeferredObjects();
Pad();
}
void StartupSerializer::SerializeStrongReferences(
const DisallowGarbageCollection& no_gc) {
Isolate* isolate = this->isolate();
// No active threads.
CHECK_NULL(isolate->thread_manager()->FirstThreadStateInUse());
SanitizeIsolateScope sanitize_isolate(
isolate, allow_active_isolate_for_testing(), no_gc);
// Visit smi roots and immortal immovables first to make sure they end up in
// the first page.
isolate->heap()->IterateSmiRoots(this);
isolate->heap()->IterateRoots(
this, base::EnumSet<SkipRoot>{SkipRoot::kUnserializable, SkipRoot::kWeak,
SkipRoot::kTracedHandles});
}
SerializedHandleChecker::SerializedHandleChecker(
Isolate* isolate, std::vector<Tagged<Context>>* contexts)
: isolate_(isolate) {
AddToSet(isolate->heap()->serialized_objects());
for (auto const& context : *contexts) {
AddToSet(context->serialized_objects());
}
}
bool StartupSerializer::SerializeUsingSharedHeapObjectCache(
SnapshotByteSink* sink, Handle<HeapObject> obj) {
return shared_heap_serializer_->SerializeUsingSharedHeapObjectCache(sink,
obj);
}
void StartupSerializer::SerializeUsingStartupObjectCache(
SnapshotByteSink* sink, Handle<HeapObject> obj) {
int cache_index = SerializeInObjectCache(obj);
sink->Put(kStartupObjectCache, "StartupObjectCache");
sink->PutUint30(cache_index, "startup_object_cache_index");
}
void StartupSerializer::CheckNoDirtyFinalizationRegistries() {
Isolate* isolate = this->isolate();
CHECK(IsUndefined(isolate->heap()->dirty_js_finalization_registries_list(),
isolate));
CHECK(IsUndefined(
isolate->heap()->dirty_js_finalization_registries_list_tail(), isolate));
}
void SerializedHandleChecker::AddToSet(Tagged<FixedArray> serialized) {
int length = serialized->length();
for (int i = 0; i < length; i++) serialized_.insert(serialized->get(i));
}
void SerializedHandleChecker::VisitRootPointers(Root root,
const char* description,
FullObjectSlot start,
FullObjectSlot end) {
for (FullObjectSlot p = start; p < end; ++p) {
if (serialized_.find(*p) != serialized_.end()) continue;
PrintF("%s handle not serialized: ",
root == Root::kGlobalHandles ? "global" : "eternal");
Print(*p);
PrintF("\n");
ok_ = false;
}
}
bool SerializedHandleChecker::CheckGlobalAndEternalHandles() {
isolate_->global_handles()->IterateAllRoots(this);
isolate_->traced_handles()->Iterate(this);
isolate_->eternal_handles()->IterateAllRoots(this);
return ok_;
}
} // namespace internal
} // namespace v8
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