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// Copyright 2018 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/read-only-deserializer.h"
#include "src/api/api.h"
#include "src/common/globals.h"
#include "src/execution/v8threads.h"
#include "src/heap/heap-inl.h" // crbug.com/v8/8499
#include "src/heap/read-only-heap.h"
#include "src/logging/counters-scopes.h"
#include "src/objects/slots.h"
#include "src/roots/static-roots.h"
#include "src/snapshot/snapshot-data.h"
namespace v8 {
namespace internal {
ReadOnlyDeserializer::ReadOnlyDeserializer(Isolate* isolate,
const SnapshotData* data,
bool can_rehash)
: Deserializer(isolate, data->Payload(), data->GetMagicNumber(), false,
can_rehash) {}
void ReadOnlyDeserializer::DeserializeIntoIsolate() {
NestedTimedHistogramScope histogram_timer(
isolate()->counters()->snapshot_deserialize_rospace());
HandleScope scope(isolate());
ReadOnlyHeap* ro_heap = isolate()->read_only_heap();
// No active threads.
DCHECK_NULL(isolate()->thread_manager()->FirstThreadStateInUse());
// No active handles.
DCHECK(isolate()->handle_scope_implementer()->blocks()->empty());
// Read-only object cache is not yet populated.
DCHECK(!ro_heap->read_only_object_cache_is_initialized());
// Startup object cache is not yet populated.
DCHECK(isolate()->startup_object_cache()->empty());
// Builtins are not yet created.
DCHECK(!isolate()->builtins()->is_initialized());
{
ReadOnlyRoots roots(isolate());
if (V8_STATIC_ROOTS_BOOL) {
// When static roots are enabled, RO space is deserialized as a verbatim
// byte copy without going through any normal deserializer logic.
ro_heap->read_only_space()->InitFromMemoryDump(isolate(), source());
roots.InitFromStaticRootsTable(isolate()->cage_base());
ro_heap->read_only_space()->RepairFreeSpacesAfterDeserialization();
} else {
roots.Iterate(this);
// Deserialize the Read-only Object Cache.
for (;;) {
Object* object = ro_heap->ExtendReadOnlyObjectCache();
// During deserialization, the visitor populates the read-only object
// cache and eventually terminates the cache with undefined.
VisitRootPointer(Root::kReadOnlyObjectCache, nullptr,
FullObjectSlot(object));
if (object->IsUndefined(roots)) break;
}
DeserializeDeferredObjects();
}
#ifdef DEBUG
roots.VerifyNameForProtectors();
#endif
roots.VerifyNameForProtectorsPages();
}
PostProcessNewObjectsIfStaticRootsEnabled();
if (should_rehash()) {
isolate()->heap()->InitializeHashSeed();
Rehash();
}
}
#ifdef V8_STATIC_ROOTS
void ReadOnlyDeserializer::PostProcessNewObjectsIfStaticRootsEnabled() {
// Since we are not deserializing individual objects we need to scan the
// heap and search for objects that need post-processing.
//
// See also Deserializer<IsolateT>::PostProcessNewObject.
//
// TODO(olivf): Make the V8_STATIC_ROOTS configuration use normal
// deserializer paths.
ReadOnlyHeapObjectIterator iterator(isolate()->read_only_heap());
PtrComprCageBase cage_base(isolate());
for (HeapObject object = iterator.Next(); !object.is_null();
object = iterator.Next()) {
const InstanceType instance_type = object.map(cage_base).instance_type();
if (should_rehash()) {
if (InstanceTypeChecker::IsString(instance_type)) {
String str = String::cast(object);
str.set_raw_hash_field(Name::kEmptyHashField);
PushObjectToRehash(handle(str, isolate()));
} else if (object.NeedsRehashing(instance_type)) {
PushObjectToRehash(handle(object, isolate()));
}
}
if (InstanceTypeChecker::IsCode(instance_type)) {
Code code = Code::cast(object);
code.init_code_entry_point(main_thread_isolate(), kNullAddress);
// RO space only contains builtin Code objects which don't have an
// attached InstructionStream.
DCHECK(code.is_builtin());
DCHECK(!code.has_instruction_stream());
code.SetEntryPointForOffHeapBuiltin(main_thread_isolate(),
code.OffHeapInstructionStart());
}
}
}
#endif // V8_STATIC_ROOTS
} // namespace internal
} // namespace v8
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