| // 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/deserializer.h" |
| |
| #include "src/codegen/assembler-inl.h" |
| #include "src/execution/isolate.h" |
| #include "src/heap/heap-inl.h" |
| #include "src/heap/heap-write-barrier-inl.h" |
| #include "src/heap/read-only-heap.h" |
| #include "src/interpreter/interpreter.h" |
| #include "src/logging/log.h" |
| #include "src/objects/api-callbacks.h" |
| #include "src/objects/cell-inl.h" |
| #include "src/objects/hash-table.h" |
| #include "src/objects/js-array-buffer-inl.h" |
| #include "src/objects/js-array-inl.h" |
| #include "src/objects/maybe-object.h" |
| #include "src/objects/objects-body-descriptors-inl.h" |
| #include "src/objects/slots.h" |
| #include "src/objects/smi.h" |
| #include "src/objects/string.h" |
| #include "src/roots/roots.h" |
| #include "src/snapshot/natives.h" |
| #include "src/snapshot/snapshot.h" |
| #include "src/tracing/trace-event.h" |
| #include "src/tracing/traced-value.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| template <typename TSlot> |
| TSlot Deserializer::Write(TSlot dest, MaybeObject value) { |
| DCHECK(!allocator()->next_reference_is_weak()); |
| dest.store(value); |
| return dest + 1; |
| } |
| |
| template <typename TSlot> |
| TSlot Deserializer::WriteAddress(TSlot dest, Address value) { |
| DCHECK(!allocator()->next_reference_is_weak()); |
| memcpy(dest.ToVoidPtr(), &value, kSystemPointerSize); |
| STATIC_ASSERT(IsAligned(kSystemPointerSize, TSlot::kSlotDataSize)); |
| return dest + (kSystemPointerSize / TSlot::kSlotDataSize); |
| } |
| |
| void Deserializer::Initialize(Isolate* isolate) { |
| DCHECK_NULL(isolate_); |
| DCHECK_NOT_NULL(isolate); |
| isolate_ = isolate; |
| allocator()->Initialize(isolate->heap()); |
| |
| #ifdef DEBUG |
| // The read-only deserializer is run by read-only heap set-up before the heap |
| // is fully set up. External reference table relies on a few parts of this |
| // set-up (like old-space), so it may be uninitialized at this point. |
| if (isolate->isolate_data()->external_reference_table()->is_initialized()) { |
| // Count the number of external references registered through the API. |
| num_api_references_ = 0; |
| if (isolate_->api_external_references() != nullptr) { |
| while (isolate_->api_external_references()[num_api_references_] != 0) { |
| num_api_references_++; |
| } |
| } |
| } |
| #endif // DEBUG |
| CHECK_EQ(magic_number_, SerializedData::kMagicNumber); |
| } |
| |
| void Deserializer::Rehash() { |
| DCHECK(can_rehash() || deserializing_user_code()); |
| for (HeapObject item : to_rehash_) { |
| item.RehashBasedOnMap(ReadOnlyRoots(isolate_)); |
| } |
| } |
| |
| Deserializer::~Deserializer() { |
| #ifdef DEBUG |
| // Do not perform checks if we aborted deserialization. |
| if (source_.position() == 0) return; |
| // Check that we only have padding bytes remaining. |
| while (source_.HasMore()) DCHECK_EQ(kNop, source_.Get()); |
| // Check that we've fully used all reserved space. |
| DCHECK(allocator()->ReservationsAreFullyUsed()); |
| #endif // DEBUG |
| } |
| |
| // This is called on the roots. It is the driver of the deserialization |
| // process. It is also called on the body of each function. |
| void Deserializer::VisitRootPointers(Root root, const char* description, |
| FullObjectSlot start, FullObjectSlot end) { |
| // We are reading to a location outside of JS heap, so pass kNew to avoid |
| // triggering write barriers. |
| ReadData(FullMaybeObjectSlot(start), FullMaybeObjectSlot(end), |
| SnapshotSpace::kNew, kNullAddress); |
| } |
| |
| void Deserializer::Synchronize(VisitorSynchronization::SyncTag tag) { |
| static const byte expected = kSynchronize; |
| CHECK_EQ(expected, source_.Get()); |
| } |
| |
| void Deserializer::DeserializeDeferredObjects() { |
| for (int code = source_.Get(); code != kSynchronize; code = source_.Get()) { |
| switch (code) { |
| case kAlignmentPrefix: |
| case kAlignmentPrefix + 1: |
| case kAlignmentPrefix + 2: { |
| int alignment = code - (SerializerDeserializer::kAlignmentPrefix - 1); |
| allocator()->SetAlignment(static_cast<AllocationAlignment>(alignment)); |
| break; |
| } |
| default: { |
| const int space_number = code & kSpaceMask; |
| DCHECK_LE(space_number, kNumberOfSpaces); |
| DCHECK_EQ(code - space_number, kNewObject); |
| SnapshotSpace space = static_cast<SnapshotSpace>(space_number); |
| HeapObject object = GetBackReferencedObject(space); |
| int size = source_.GetInt() << kTaggedSizeLog2; |
| Address obj_address = object.address(); |
| // Object's map is already initialized, now read the rest. |
| MaybeObjectSlot start(obj_address + kTaggedSize); |
| MaybeObjectSlot end(obj_address + size); |
| bool filled = ReadData(start, end, space, obj_address); |
| CHECK(filled); |
| DCHECK(CanBeDeferred(object)); |
| PostProcessNewObject(object, space); |
| } |
| } |
| } |
| } |
| |
| void Deserializer::LogNewObjectEvents() { |
| { |
| // {new_maps_} and {new_code_objects_} are vectors containing raw |
| // pointers, hence there should be no GC happening. |
| DisallowHeapAllocation no_gc; |
| // Issue code events for newly deserialized code objects. |
| LOG_CODE_EVENT(isolate_, LogCodeObjects()); |
| } |
| LOG_CODE_EVENT(isolate_, LogCompiledFunctions()); |
| LogNewMapEvents(); |
| } |
| |
| void Deserializer::LogNewMapEvents() { |
| DisallowHeapAllocation no_gc; |
| for (Map map : new_maps()) { |
| DCHECK(FLAG_trace_maps); |
| LOG(isolate_, MapCreate(map)); |
| LOG(isolate_, MapDetails(map)); |
| } |
| } |
| |
| void Deserializer::LogScriptEvents(Script script) { |
| DisallowHeapAllocation no_gc; |
| LOG(isolate_, |
| ScriptEvent(Logger::ScriptEventType::kDeserialize, script.id())); |
| LOG(isolate_, ScriptDetails(script)); |
| TRACE_EVENT_OBJECT_CREATED_WITH_ID( |
| TRACE_DISABLED_BY_DEFAULT("v8.compile"), "Script", |
| TRACE_ID_WITH_SCOPE("v8::internal::Script", script.id())); |
| TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID( |
| TRACE_DISABLED_BY_DEFAULT("v8.compile"), "Script", |
| TRACE_ID_WITH_SCOPE("v8::internal::Script", script.id()), |
| script.ToTracedValue()); |
| } |
| |
| StringTableInsertionKey::StringTableInsertionKey(String string) |
| : StringTableKey(ComputeHashField(string), string.length()), |
| string_(string) { |
| DCHECK(string.IsInternalizedString()); |
| } |
| |
| bool StringTableInsertionKey::IsMatch(String string) { |
| // We want to compare the content of two strings here. |
| return string_.SlowEquals(string); |
| } |
| |
| Handle<String> StringTableInsertionKey::AsHandle(Isolate* isolate) { |
| return handle(string_, isolate); |
| } |
| |
| uint32_t StringTableInsertionKey::ComputeHashField(String string) { |
| // Make sure hash_field() is computed. |
| string.Hash(); |
| return string.hash_field(); |
| } |
| |
| namespace { |
| |
| String ForwardStringIfExists(Isolate* isolate, StringTableInsertionKey* key) { |
| StringTable table = isolate->heap()->string_table(); |
| int entry = table.FindEntry(isolate, key); |
| if (entry == kNotFound) return String(); |
| |
| String canonical = String::cast(table.KeyAt(entry)); |
| DCHECK_NE(canonical, key->string()); |
| key->string().MakeThin(isolate, canonical); |
| return canonical; |
| } |
| |
| } // namespace |
| |
| HeapObject Deserializer::PostProcessNewObject(HeapObject obj, |
| SnapshotSpace space) { |
| if ((FLAG_rehash_snapshot && can_rehash_) || deserializing_user_code()) { |
| if (obj.IsString()) { |
| // Uninitialize hash field as we need to recompute the hash. |
| String string = String::cast(obj); |
| string.set_hash_field(String::kEmptyHashField); |
| // Rehash strings before read-only space is sealed. Strings outside |
| // read-only space are rehashed lazily. (e.g. when rehashing dictionaries) |
| if (space == SnapshotSpace::kReadOnlyHeap) { |
| to_rehash_.push_back(obj); |
| } |
| } else if (obj.NeedsRehashing()) { |
| to_rehash_.push_back(obj); |
| } |
| } |
| |
| if (deserializing_user_code()) { |
| if (obj.IsString()) { |
| String string = String::cast(obj); |
| if (string.IsInternalizedString()) { |
| // Canonicalize the internalized string. If it already exists in the |
| // string table, set it to forward to the existing one. |
| StringTableInsertionKey key(string); |
| String canonical = ForwardStringIfExists(isolate_, &key); |
| |
| if (!canonical.is_null()) return canonical; |
| |
| new_internalized_strings_.push_back(handle(string, isolate_)); |
| return string; |
| } |
| } else if (obj.IsScript()) { |
| new_scripts_.push_back(handle(Script::cast(obj), isolate_)); |
| } else if (obj.IsAllocationSite()) { |
| // We should link new allocation sites, but we can't do this immediately |
| // because |AllocationSite::HasWeakNext()| internally accesses |
| // |Heap::roots_| that may not have been initialized yet. So defer this to |
| // |ObjectDeserializer::CommitPostProcessedObjects()|. |
| new_allocation_sites_.push_back(AllocationSite::cast(obj)); |
| } else { |
| DCHECK(CanBeDeferred(obj)); |
| } |
| } |
| if (obj.IsScript()) { |
| LogScriptEvents(Script::cast(obj)); |
| } else if (obj.IsCode()) { |
| // We flush all code pages after deserializing the startup snapshot. |
| // Hence we only remember each individual code object when deserializing |
| // user code. |
| if (deserializing_user_code() || space == SnapshotSpace::kLargeObject) { |
| new_code_objects_.push_back(Code::cast(obj)); |
| } |
| } else if (FLAG_trace_maps && obj.IsMap()) { |
| // Keep track of all seen Maps to log them later since they might be only |
| // partially initialized at this point. |
| new_maps_.push_back(Map::cast(obj)); |
| } else if (obj.IsAccessorInfo()) { |
| #ifdef USE_SIMULATOR |
| accessor_infos_.push_back(AccessorInfo::cast(obj)); |
| #endif |
| } else if (obj.IsCallHandlerInfo()) { |
| #ifdef USE_SIMULATOR |
| call_handler_infos_.push_back(CallHandlerInfo::cast(obj)); |
| #endif |
| } else if (obj.IsExternalString()) { |
| if (obj.map() == ReadOnlyRoots(isolate_).native_source_string_map()) { |
| ExternalOneByteString string = ExternalOneByteString::cast(obj); |
| DCHECK(string.is_uncached()); |
| string.SetResource( |
| isolate_, NativesExternalStringResource::DecodeForDeserialization( |
| string.resource())); |
| } else { |
| ExternalString string = ExternalString::cast(obj); |
| uint32_t index = string.resource_as_uint32(); |
| Address address = |
| static_cast<Address>(isolate_->api_external_references()[index]); |
| string.set_address_as_resource(address); |
| isolate_->heap()->UpdateExternalString(string, 0, |
| string.ExternalPayloadSize()); |
| } |
| isolate_->heap()->RegisterExternalString(String::cast(obj)); |
| } else if (obj.IsJSDataView()) { |
| JSDataView data_view = JSDataView::cast(obj); |
| JSArrayBuffer buffer = JSArrayBuffer::cast(data_view.buffer()); |
| data_view.set_data_pointer( |
| reinterpret_cast<uint8_t*>(buffer.backing_store()) + |
| data_view.byte_offset()); |
| } else if (obj.IsJSTypedArray()) { |
| JSTypedArray typed_array = JSTypedArray::cast(obj); |
| // Only fixup for the off-heap case. |
| if (!typed_array.is_on_heap()) { |
| Smi store_index( |
| reinterpret_cast<Address>(typed_array.external_pointer())); |
| byte* backing_store = off_heap_backing_stores_[store_index.value()] + |
| typed_array.byte_offset(); |
| typed_array.set_external_pointer(backing_store); |
| } |
| } else if (obj.IsJSArrayBuffer()) { |
| JSArrayBuffer buffer = JSArrayBuffer::cast(obj); |
| // Only fixup for the off-heap case. |
| if (buffer.backing_store() != nullptr) { |
| Smi store_index(reinterpret_cast<Address>(buffer.backing_store())); |
| void* backing_store = off_heap_backing_stores_[store_index.value()]; |
| |
| buffer.set_backing_store(backing_store); |
| isolate_->heap()->RegisterNewArrayBuffer(buffer); |
| } |
| } else if (obj.IsBytecodeArray()) { |
| // TODO(mythria): Remove these once we store the default values for these |
| // fields in the serializer. |
| BytecodeArray bytecode_array = BytecodeArray::cast(obj); |
| bytecode_array.set_osr_loop_nesting_level(0); |
| } |
| #ifdef DEBUG |
| if (obj.IsDescriptorArray()) { |
| DescriptorArray descriptor_array = DescriptorArray::cast(obj); |
| DCHECK_EQ(0, descriptor_array.raw_number_of_marked_descriptors()); |
| } |
| #endif |
| |
| // Check alignment. |
| DCHECK_EQ(0, Heap::GetFillToAlign(obj.address(), |
| HeapObject::RequiredAlignment(obj.map()))); |
| return obj; |
| } |
| |
| HeapObject Deserializer::GetBackReferencedObject(SnapshotSpace space) { |
| HeapObject obj; |
| switch (space) { |
| case SnapshotSpace::kLargeObject: |
| obj = allocator()->GetLargeObject(source_.GetInt()); |
| break; |
| case SnapshotSpace::kMap: |
| obj = allocator()->GetMap(source_.GetInt()); |
| break; |
| case SnapshotSpace::kReadOnlyHeap: { |
| uint32_t chunk_index = source_.GetInt(); |
| uint32_t chunk_offset = source_.GetInt(); |
| if (isolate()->heap()->deserialization_complete()) { |
| PagedSpace* read_only_space = isolate()->heap()->read_only_space(); |
| Page* page = read_only_space->first_page(); |
| for (uint32_t i = 0; i < chunk_index; ++i) { |
| page = page->next_page(); |
| } |
| Address address = page->OffsetToAddress(chunk_offset); |
| obj = HeapObject::FromAddress(address); |
| } else { |
| obj = allocator()->GetObject(space, chunk_index, chunk_offset); |
| } |
| break; |
| } |
| default: { |
| uint32_t chunk_index = source_.GetInt(); |
| uint32_t chunk_offset = source_.GetInt(); |
| obj = allocator()->GetObject(space, chunk_index, chunk_offset); |
| break; |
| } |
| } |
| |
| if (deserializing_user_code() && obj.IsThinString()) { |
| obj = ThinString::cast(obj).actual(); |
| } |
| |
| hot_objects_.Add(obj); |
| DCHECK(!HasWeakHeapObjectTag(obj)); |
| return obj; |
| } |
| |
| HeapObject Deserializer::ReadObject() { |
| MaybeObject object; |
| // We are reading to a location outside of JS heap, so pass kNew to avoid |
| // triggering write barriers. |
| bool filled = |
| ReadData(FullMaybeObjectSlot(&object), FullMaybeObjectSlot(&object + 1), |
| SnapshotSpace::kNew, kNullAddress); |
| CHECK(filled); |
| return object.GetHeapObjectAssumeStrong(); |
| } |
| |
| HeapObject Deserializer::ReadObject(SnapshotSpace space) { |
| const int size = source_.GetInt() << kObjectAlignmentBits; |
| |
| Address address = allocator()->Allocate(space, size); |
| HeapObject obj = HeapObject::FromAddress(address); |
| |
| isolate_->heap()->OnAllocationEvent(obj, size); |
| MaybeObjectSlot current(address); |
| MaybeObjectSlot limit(address + size); |
| |
| if (ReadData(current, limit, space, address)) { |
| // Only post process if object content has not been deferred. |
| obj = PostProcessNewObject(obj, space); |
| } |
| |
| #ifdef DEBUG |
| if (obj.IsCode()) { |
| DCHECK_EQ(space, SnapshotSpace::kCode); |
| } else { |
| DCHECK_NE(space, SnapshotSpace::kCode); |
| } |
| #endif // DEBUG |
| return obj; |
| } |
| |
| void Deserializer::ReadCodeObjectBody(SnapshotSpace space, |
| Address code_object_address) { |
| // At this point the code object is already allocated, its map field is |
| // initialized and its raw data fields and code stream are also read. |
| // Now we read the rest of code header's fields. |
| MaybeObjectSlot current(code_object_address + HeapObject::kHeaderSize); |
| MaybeObjectSlot limit(code_object_address + Code::kDataStart); |
| bool filled = ReadData(current, limit, space, code_object_address); |
| CHECK(filled); |
| |
| // Now iterate RelocInfos the same way it was done by the serialzier and |
| // deserialize respective data into RelocInfos. |
| Code code = Code::cast(HeapObject::FromAddress(code_object_address)); |
| RelocIterator it(code, Code::BodyDescriptor::kRelocModeMask); |
| for (; !it.done(); it.next()) { |
| RelocInfo rinfo = *it.rinfo(); |
| rinfo.Visit(this); |
| } |
| } |
| |
| void Deserializer::VisitCodeTarget(Code host, RelocInfo* rinfo) { |
| HeapObject object = ReadObject(); |
| rinfo->set_target_address(Code::cast(object).raw_instruction_start()); |
| } |
| |
| void Deserializer::VisitEmbeddedPointer(Code host, RelocInfo* rinfo) { |
| HeapObject object = ReadObject(); |
| // Embedded object reference must be a strong one. |
| rinfo->set_target_object(isolate_->heap(), object); |
| } |
| |
| void Deserializer::VisitRuntimeEntry(Code host, RelocInfo* rinfo) { |
| // We no longer serialize code that contains runtime entries. |
| UNREACHABLE(); |
| } |
| |
| void Deserializer::VisitExternalReference(Code host, RelocInfo* rinfo) { |
| byte data = source_.Get(); |
| CHECK_EQ(data, kExternalReference); |
| |
| Address address = ReadExternalReferenceCase(); |
| |
| if (rinfo->IsCodedSpecially()) { |
| Address location_of_branch_data = rinfo->pc(); |
| Assembler::deserialization_set_special_target_at(location_of_branch_data, |
| host, address); |
| } else { |
| WriteUnalignedValue(rinfo->target_address_address(), address); |
| } |
| } |
| |
| void Deserializer::VisitInternalReference(Code host, RelocInfo* rinfo) { |
| byte data = source_.Get(); |
| CHECK_EQ(data, kInternalReference); |
| |
| // Internal reference target is encoded as an offset from code entry. |
| int target_offset = source_.GetInt(); |
| DCHECK_LT(static_cast<unsigned>(target_offset), |
| static_cast<unsigned>(host.raw_instruction_size())); |
| Address target = host.entry() + target_offset; |
| Assembler::deserialization_set_target_internal_reference_at( |
| rinfo->pc(), target, rinfo->rmode()); |
| } |
| |
| void Deserializer::VisitOffHeapTarget(Code host, RelocInfo* rinfo) { |
| DCHECK(FLAG_embedded_builtins); |
| byte data = source_.Get(); |
| CHECK_EQ(data, kOffHeapTarget); |
| |
| int builtin_index = source_.GetInt(); |
| DCHECK(Builtins::IsBuiltinId(builtin_index)); |
| |
| CHECK_NOT_NULL(isolate_->embedded_blob()); |
| EmbeddedData d = EmbeddedData::FromBlob(); |
| Address address = d.InstructionStartOfBuiltin(builtin_index); |
| CHECK_NE(kNullAddress, address); |
| |
| // TODO(ishell): implement RelocInfo::set_target_off_heap_target() |
| if (RelocInfo::OffHeapTargetIsCodedSpecially()) { |
| Address location_of_branch_data = rinfo->pc(); |
| Assembler::deserialization_set_special_target_at(location_of_branch_data, |
| host, address); |
| } else { |
| WriteUnalignedValue(rinfo->target_address_address(), address); |
| } |
| } |
| |
| template <typename TSlot> |
| TSlot Deserializer::ReadRepeatedObject(TSlot current, int repeat_count) { |
| CHECK_LE(2, repeat_count); |
| |
| HeapObject heap_object = ReadObject(); |
| DCHECK(!Heap::InYoungGeneration(heap_object)); |
| for (int i = 0; i < repeat_count; i++) { |
| // Repeated values are not subject to the write barrier so we don't need |
| // to trigger it. |
| current = Write(current, MaybeObject::FromObject(heap_object)); |
| } |
| return current; |
| } |
| |
| static void NoExternalReferencesCallback() { |
| // The following check will trigger if a function or object template |
| // with references to native functions have been deserialized from |
| // snapshot, but no actual external references were provided when the |
| // isolate was created. |
| CHECK_WITH_MSG(false, "No external references provided via API"); |
| } |
| |
| template <typename TSlot> |
| bool Deserializer::ReadData(TSlot current, TSlot limit, |
| SnapshotSpace source_space, |
| Address current_object_address) { |
| Isolate* const isolate = isolate_; |
| // Write barrier support costs around 1% in startup time. In fact there |
| // are no new space objects in current boot snapshots, so it's not needed, |
| // but that may change. |
| bool write_barrier_needed = (current_object_address != kNullAddress && |
| source_space != SnapshotSpace::kNew && |
| source_space != SnapshotSpace::kCode); |
| while (current < limit) { |
| byte data = source_.Get(); |
| switch (data) { |
| #define CASE_STATEMENT(bytecode, snapshot_space) \ |
| case bytecode + static_cast<int>(snapshot_space): \ |
| STATIC_ASSERT((static_cast<int>(snapshot_space) & ~kSpaceMask) == 0); |
| |
| #define CASE_BODY(bytecode, space_number_if_any) \ |
| current = ReadDataCase<TSlot, bytecode, space_number_if_any>( \ |
| isolate, current, current_object_address, data, write_barrier_needed); \ |
| break; |
| |
| // This generates a case and a body for the new space (which has to do extra |
| // write barrier handling) and handles the other spaces with fall-through cases |
| // and one body. |
| #define ALL_SPACES(bytecode) \ |
| CASE_STATEMENT(bytecode, SnapshotSpace::kNew) \ |
| CASE_BODY(bytecode, SnapshotSpace::kNew) \ |
| CASE_STATEMENT(bytecode, SnapshotSpace::kOld) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(bytecode, SnapshotSpace::kCode) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(bytecode, SnapshotSpace::kMap) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(bytecode, SnapshotSpace::kLargeObject) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(bytecode, SnapshotSpace::kReadOnlyHeap) \ |
| CASE_BODY(bytecode, kAnyOldSpace) |
| |
| #define FOUR_CASES(byte_code) \ |
| case byte_code: \ |
| case byte_code + 1: \ |
| case byte_code + 2: \ |
| case byte_code + 3: |
| |
| #define SIXTEEN_CASES(byte_code) \ |
| FOUR_CASES(byte_code) \ |
| FOUR_CASES(byte_code + 4) \ |
| FOUR_CASES(byte_code + 8) \ |
| FOUR_CASES(byte_code + 12) |
| |
| #define SINGLE_CASE(bytecode, space) \ |
| CASE_STATEMENT(bytecode, space) \ |
| CASE_BODY(bytecode, space) |
| |
| // Deserialize a new object and write a pointer to it to the current |
| // object. |
| ALL_SPACES(kNewObject) |
| // Find a recently deserialized object using its offset from the current |
| // allocation point and write a pointer to it to the current object. |
| ALL_SPACES(kBackref) |
| // Find an object in the roots array and write a pointer to it to the |
| // current object. |
| SINGLE_CASE(kRootArray, SnapshotSpace::kReadOnlyHeap) |
| // Find an object in the partial snapshots cache and write a pointer to it |
| // to the current object. |
| SINGLE_CASE(kPartialSnapshotCache, SnapshotSpace::kReadOnlyHeap) |
| // Find an object in the partial snapshots cache and write a pointer to it |
| // to the current object. |
| SINGLE_CASE(kReadOnlyObjectCache, SnapshotSpace::kReadOnlyHeap) |
| // Find an object in the attached references and write a pointer to it to |
| // the current object. |
| SINGLE_CASE(kAttachedReference, SnapshotSpace::kReadOnlyHeap) |
| |
| #undef CASE_STATEMENT |
| #undef CASE_BODY |
| #undef ALL_SPACES |
| |
| // Find an external reference and write a pointer to it to the current |
| // object. |
| case kExternalReference: { |
| Address address = ReadExternalReferenceCase(); |
| current = WriteAddress(current, address); |
| break; |
| } |
| |
| case kInternalReference: |
| case kOffHeapTarget: { |
| // These bytecodes are expected only during RelocInfo iteration. |
| UNREACHABLE(); |
| break; |
| } |
| |
| case kNop: |
| break; |
| |
| case kNextChunk: { |
| int space = source_.Get(); |
| allocator()->MoveToNextChunk(static_cast<SnapshotSpace>(space)); |
| break; |
| } |
| |
| case kDeferred: { |
| // Deferred can only occur right after the heap object header. |
| DCHECK_EQ(current.address(), current_object_address + kTaggedSize); |
| HeapObject obj = HeapObject::FromAddress(current_object_address); |
| // If the deferred object is a map, its instance type may be used |
| // during deserialization. Initialize it with a temporary value. |
| if (obj.IsMap()) Map::cast(obj).set_instance_type(FILLER_TYPE); |
| current = limit; |
| return false; |
| } |
| |
| case kSynchronize: |
| // If we get here then that indicates that you have a mismatch between |
| // the number of GC roots when serializing and deserializing. |
| UNREACHABLE(); |
| |
| // Deserialize raw data of variable length. |
| case kVariableRawData: { |
| int size_in_bytes = source_.GetInt(); |
| DCHECK(IsAligned(size_in_bytes, kTaggedSize)); |
| source_.CopyRaw(current.ToVoidPtr(), size_in_bytes); |
| current = TSlot(current.address() + size_in_bytes); |
| break; |
| } |
| |
| // Deserialize raw code directly into the body of the code object. |
| case kVariableRawCode: { |
| // VariableRawCode can only occur right after the heap object header. |
| DCHECK_EQ(current.address(), current_object_address + kTaggedSize); |
| int size_in_bytes = source_.GetInt(); |
| DCHECK(IsAligned(size_in_bytes, kTaggedSize)); |
| source_.CopyRaw( |
| reinterpret_cast<void*>(current_object_address + Code::kDataStart), |
| size_in_bytes); |
| // Deserialize tagged fields in the code object header and reloc infos. |
| ReadCodeObjectBody(source_space, current_object_address); |
| // Set current to the code object end. |
| current = TSlot(current.address() + Code::kDataStart - |
| HeapObject::kHeaderSize + size_in_bytes); |
| CHECK_EQ(current, limit); |
| break; |
| } |
| |
| case kVariableRepeat: { |
| int repeats = DecodeVariableRepeatCount(source_.GetInt()); |
| current = ReadRepeatedObject(current, repeats); |
| break; |
| } |
| |
| case kOffHeapBackingStore: { |
| int byte_length = source_.GetInt(); |
| byte* backing_store = static_cast<byte*>( |
| isolate->array_buffer_allocator()->AllocateUninitialized( |
| byte_length)); |
| CHECK_NOT_NULL(backing_store); |
| source_.CopyRaw(backing_store, byte_length); |
| off_heap_backing_stores_.push_back(backing_store); |
| break; |
| } |
| |
| case kApiReference: { |
| uint32_t reference_id = static_cast<uint32_t>(source_.GetInt()); |
| Address address; |
| if (isolate->api_external_references()) { |
| DCHECK_WITH_MSG( |
| reference_id < num_api_references_, |
| "too few external references provided through the API"); |
| address = static_cast<Address>( |
| isolate->api_external_references()[reference_id]); |
| } else { |
| address = reinterpret_cast<Address>(NoExternalReferencesCallback); |
| } |
| current = WriteAddress(current, address); |
| break; |
| } |
| |
| case kClearedWeakReference: |
| current = Write(current, HeapObjectReference::ClearedValue(isolate_)); |
| break; |
| |
| case kWeakPrefix: |
| DCHECK(!allocator()->next_reference_is_weak()); |
| allocator()->set_next_reference_is_weak(true); |
| break; |
| |
| case kAlignmentPrefix: |
| case kAlignmentPrefix + 1: |
| case kAlignmentPrefix + 2: { |
| int alignment = data - (SerializerDeserializer::kAlignmentPrefix - 1); |
| allocator()->SetAlignment(static_cast<AllocationAlignment>(alignment)); |
| break; |
| } |
| |
| // First kNumberOfRootArrayConstants roots are guaranteed to be in |
| // the old space. |
| STATIC_ASSERT( |
| static_cast<int>(RootIndex::kFirstImmortalImmovableRoot) == 0); |
| STATIC_ASSERT(kNumberOfRootArrayConstants <= |
| static_cast<int>(RootIndex::kLastImmortalImmovableRoot)); |
| STATIC_ASSERT(kNumberOfRootArrayConstants == 32); |
| SIXTEEN_CASES(kRootArrayConstants) |
| SIXTEEN_CASES(kRootArrayConstants + 16) { |
| int id = data & kRootArrayConstantsMask; |
| RootIndex root_index = static_cast<RootIndex>(id); |
| MaybeObject object = MaybeObject::FromObject(isolate->root(root_index)); |
| DCHECK(!Heap::InYoungGeneration(object)); |
| current = Write(current, object); |
| break; |
| } |
| |
| STATIC_ASSERT(kNumberOfHotObjects == 8); |
| FOUR_CASES(kHotObject) |
| FOUR_CASES(kHotObject + 4) { |
| int index = data & kHotObjectMask; |
| Object hot_object = hot_objects_.Get(index); |
| MaybeObject hot_maybe_object = MaybeObject::FromObject(hot_object); |
| if (allocator()->GetAndClearNextReferenceIsWeak()) { |
| hot_maybe_object = MaybeObject::MakeWeak(hot_maybe_object); |
| } |
| // Don't update current pointer here as it may be needed for write |
| // barrier. |
| Write(current, hot_maybe_object); |
| if (write_barrier_needed && Heap::InYoungGeneration(hot_object)) { |
| HeapObject current_object = |
| HeapObject::FromAddress(current_object_address); |
| GenerationalBarrier(current_object, |
| MaybeObjectSlot(current.address()), |
| hot_maybe_object); |
| } |
| ++current; |
| break; |
| } |
| |
| // Deserialize raw data of fixed length from 1 to 32 words. |
| STATIC_ASSERT(kNumberOfFixedRawData == 32); |
| SIXTEEN_CASES(kFixedRawData) |
| SIXTEEN_CASES(kFixedRawData + 16) { |
| int size_in_tagged = data - kFixedRawDataStart; |
| source_.CopyRaw(current.ToVoidPtr(), size_in_tagged * kTaggedSize); |
| current += size_in_tagged; |
| break; |
| } |
| |
| STATIC_ASSERT(kNumberOfFixedRepeat == 16); |
| SIXTEEN_CASES(kFixedRepeat) { |
| int repeats = DecodeFixedRepeatCount(data); |
| current = ReadRepeatedObject(current, repeats); |
| break; |
| } |
| |
| #ifdef DEBUG |
| #define UNUSED_CASE(byte_code) \ |
| case byte_code: \ |
| UNREACHABLE(); |
| UNUSED_SERIALIZER_BYTE_CODES(UNUSED_CASE) |
| #endif |
| #undef UNUSED_CASE |
| |
| #undef SIXTEEN_CASES |
| #undef FOUR_CASES |
| #undef SINGLE_CASE |
| } |
| } |
| CHECK_EQ(limit, current); |
| return true; |
| } |
| |
| Address Deserializer::ReadExternalReferenceCase() { |
| uint32_t reference_id = static_cast<uint32_t>(source_.GetInt()); |
| return isolate_->external_reference_table()->address(reference_id); |
| } |
| |
| template <typename TSlot, SerializerDeserializer::Bytecode bytecode, |
| SnapshotSpace space_number_if_any> |
| TSlot Deserializer::ReadDataCase(Isolate* isolate, TSlot current, |
| Address current_object_address, byte data, |
| bool write_barrier_needed) { |
| bool emit_write_barrier = false; |
| SnapshotSpace space = static_cast<SnapshotSpace>( |
| space_number_if_any == kAnyOldSpace |
| ? static_cast<SnapshotSpace>(data & kSpaceMask) |
| : space_number_if_any); |
| HeapObject heap_object; |
| HeapObjectReferenceType reference_type = |
| allocator()->GetAndClearNextReferenceIsWeak() |
| ? HeapObjectReferenceType::WEAK |
| : HeapObjectReferenceType::STRONG; |
| |
| if (bytecode == kNewObject) { |
| heap_object = ReadObject(space); |
| emit_write_barrier = (space == SnapshotSpace::kNew); |
| } else if (bytecode == kBackref) { |
| heap_object = GetBackReferencedObject(space); |
| emit_write_barrier = (space == SnapshotSpace::kNew); |
| } else if (bytecode == kRootArray) { |
| int id = source_.GetInt(); |
| RootIndex root_index = static_cast<RootIndex>(id); |
| heap_object = HeapObject::cast(isolate->root(root_index)); |
| emit_write_barrier = Heap::InYoungGeneration(heap_object); |
| hot_objects_.Add(heap_object); |
| } else if (bytecode == kReadOnlyObjectCache) { |
| int cache_index = source_.GetInt(); |
| heap_object = HeapObject::cast( |
| isolate->read_only_heap()->cached_read_only_object(cache_index)); |
| DCHECK(!Heap::InYoungGeneration(heap_object)); |
| emit_write_barrier = false; |
| } else if (bytecode == kPartialSnapshotCache) { |
| int cache_index = source_.GetInt(); |
| heap_object = |
| HeapObject::cast(isolate->partial_snapshot_cache()->at(cache_index)); |
| emit_write_barrier = Heap::InYoungGeneration(heap_object); |
| } else { |
| DCHECK_EQ(bytecode, kAttachedReference); |
| int index = source_.GetInt(); |
| heap_object = *attached_objects_[index]; |
| emit_write_barrier = Heap::InYoungGeneration(heap_object); |
| } |
| HeapObjectReference heap_object_ref = |
| reference_type == HeapObjectReferenceType::STRONG |
| ? HeapObjectReference::Strong(heap_object) |
| : HeapObjectReference::Weak(heap_object); |
| // Don't update current pointer here as it may be needed for write barrier. |
| Write(current, heap_object_ref); |
| if (emit_write_barrier && write_barrier_needed) { |
| HeapObject host_object = HeapObject::FromAddress(current_object_address); |
| SLOW_DCHECK(isolate->heap()->Contains(host_object)); |
| GenerationalBarrier(host_object, MaybeObjectSlot(current.address()), |
| heap_object_ref); |
| } |
| return current + 1; |
| } |
| |
| } // namespace internal |
| } // namespace v8 |
