| // 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/assembler-inl.h" |
| #include "src/heap/heap-write-barrier-inl.h" |
| #include "src/interpreter/interpreter.h" |
| #include "src/isolate.h" |
| #include "src/log.h" |
| #include "src/objects-body-descriptors-inl.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/slots.h" |
| #include "src/objects/smi.h" |
| #include "src/objects/string.h" |
| #include "src/snapshot/natives.h" |
| #include "src/snapshot/snapshot.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // This is like a MaybeObjectSlot, except it doesn't enforce alignment. |
| // Most slots used below are aligned, but when writing into Code objects, |
| // they might not be, hence the use of UnalignedSlot and UnalignedCopy. |
| class UnalignedSlot { |
| public: |
| explicit UnalignedSlot(ObjectSlot slot) : ptr_(slot.address()) {} |
| explicit UnalignedSlot(Address address) : ptr_(address) {} |
| explicit UnalignedSlot(MaybeObject* slot) |
| : ptr_(reinterpret_cast<Address>(slot)) {} |
| explicit UnalignedSlot(Object* slot) |
| : ptr_(reinterpret_cast<Address>(slot)) {} |
| |
| inline bool operator<(const UnalignedSlot& other) const { |
| return ptr_ < other.ptr_; |
| } |
| inline bool operator==(const UnalignedSlot& other) const { |
| return ptr_ == other.ptr_; |
| } |
| |
| inline void Advance(int bytes = kPointerSize) { ptr_ += bytes; } |
| |
| inline void Write(Address value) { |
| memcpy(reinterpret_cast<void*>(ptr_), &value, sizeof(value)); |
| } |
| |
| Address address() { return ptr_; } |
| |
| private: |
| Address ptr_; |
| }; |
| |
| void Deserializer::UnalignedCopy(UnalignedSlot dest, MaybeObject value) { |
| DCHECK(!allocator()->next_reference_is_weak()); |
| dest.Write(value.ptr()); |
| } |
| |
| void Deserializer::UnalignedCopy(UnalignedSlot dest, Address value) { |
| DCHECK(!allocator()->next_reference_is_weak()); |
| dest.Write(value); |
| } |
| |
| void Deserializer::Initialize(Isolate* isolate) { |
| DCHECK_NULL(isolate_); |
| DCHECK_NOT_NULL(isolate); |
| isolate_ = isolate; |
| DCHECK_NULL(external_reference_table_); |
| external_reference_table_ = isolate->external_reference_table(); |
| #ifdef DEBUG |
| // 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(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 NEW_SPACE to |
| // avoid triggering write barriers. |
| // TODO(ishell): this will not work once we actually compress pointers. |
| STATIC_ASSERT(kTaggedSize == kSystemPointerSize); |
| ReadData(UnalignedSlot(start.address()), UnalignedSlot(end.address()), |
| NEW_SPACE, 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: { |
| int space = code & kSpaceMask; |
| DCHECK_LE(space, kNumberOfSpaces); |
| DCHECK_EQ(code - space, kNewObject); |
| HeapObject object = GetBackReferencedObject(space); |
| int size = source_.GetInt() << kPointerSizeLog2; |
| Address obj_address = object->address(); |
| UnalignedSlot start(obj_address + kPointerSize); |
| UnalignedSlot 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)); |
| } |
| |
| StringTableInsertionKey::StringTableInsertionKey(String string) |
| : StringTableKey(ComputeHashField(string)), string_(string) { |
| DCHECK(string->IsInternalizedString()); |
| } |
| |
| bool StringTableInsertionKey::IsMatch(Object string) { |
| // We know that all entries in a hash table had their hash keys created. |
| // Use that knowledge to have fast failure. |
| if (Hash() != String::cast(string)->Hash()) return false; |
| // We want to compare the content of two internalized strings here. |
| return string_->SlowEquals(String::cast(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(); |
| } |
| |
| HeapObject Deserializer::PostProcessNewObject(HeapObject obj, int 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); |
| } 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 = |
| StringTable::ForwardStringIfExists(isolate_, &key, string); |
| |
| 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 == LO_SPACE) { |
| 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->IsJSTypedArray()) { |
| JSTypedArray typed_array = JSTypedArray::cast(obj); |
| CHECK_LE(typed_array->byte_offset(), Smi::kMaxValue); |
| int32_t byte_offset = static_cast<int32_t>(typed_array->byte_offset()); |
| if (byte_offset > 0) { |
| FixedTypedArrayBase elements = |
| FixedTypedArrayBase::cast(typed_array->elements()); |
| // Must be off-heap layout. |
| DCHECK(!typed_array->is_on_heap()); |
| |
| void* pointer_with_offset = reinterpret_cast<void*>( |
| reinterpret_cast<intptr_t>(elements->external_pointer()) + |
| byte_offset); |
| elements->set_external_pointer(pointer_with_offset); |
| } |
| } 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->IsFixedTypedArrayBase()) { |
| FixedTypedArrayBase fta = FixedTypedArrayBase::cast(obj); |
| // Only fixup for the off-heap case. |
| if (fta->base_pointer() == Smi::kZero) { |
| Smi store_index(reinterpret_cast<Address>(fta->external_pointer())); |
| void* backing_store = off_heap_backing_stores_[store_index->value()]; |
| fta->set_external_pointer(backing_store); |
| } |
| } 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_interrupt_budget( |
| interpreter::Interpreter::InterruptBudget()); |
| bytecode_array->set_osr_loop_nesting_level(0); |
| } else if (obj->IsDescriptorArray()) { |
| // Reset the marking state of the descriptor array. |
| DescriptorArray descriptor_array = DescriptorArray::cast(obj); |
| descriptor_array->set_raw_number_of_marked_descriptors(0); |
| } |
| |
| // Check alignment. |
| DCHECK_EQ(0, Heap::GetFillToAlign(obj->address(), |
| HeapObject::RequiredAlignment(obj->map()))); |
| return obj; |
| } |
| |
| HeapObject Deserializer::GetBackReferencedObject(int space) { |
| HeapObject obj; |
| switch (space) { |
| case LO_SPACE: |
| obj = allocator()->GetLargeObject(source_.GetInt()); |
| break; |
| case MAP_SPACE: |
| obj = allocator()->GetMap(source_.GetInt()); |
| break; |
| case RO_SPACE: { |
| 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(static_cast<AllocationSpace>(space), |
| chunk_index, chunk_offset); |
| } |
| break; |
| } |
| default: { |
| uint32_t chunk_index = source_.GetInt(); |
| uint32_t chunk_offset = source_.GetInt(); |
| obj = allocator()->GetObject(static_cast<AllocationSpace>(space), |
| chunk_index, chunk_offset); |
| break; |
| } |
| } |
| |
| if (deserializing_user_code() && obj->IsThinString()) { |
| obj = ThinString::cast(obj)->actual(); |
| } |
| |
| hot_objects_.Add(obj); |
| DCHECK(!HasWeakHeapObjectTag(obj->ptr())); |
| return obj; |
| } |
| |
| HeapObject Deserializer::ReadObject() { |
| MaybeObject object; |
| // We are reading to a location outside of JS heap, so pass NEW_SPACE to |
| // avoid triggering write barriers. |
| bool filled = ReadData(UnalignedSlot(&object), UnalignedSlot(&object + 1), |
| NEW_SPACE, kNullAddress); |
| CHECK(filled); |
| return object.GetHeapObjectAssumeStrong(); |
| } |
| |
| HeapObject Deserializer::ReadObject(int space_number) { |
| const int size = source_.GetInt() << kObjectAlignmentBits; |
| |
| Address address = |
| allocator()->Allocate(static_cast<AllocationSpace>(space_number), size); |
| HeapObject obj = HeapObject::FromAddress(address); |
| |
| isolate_->heap()->OnAllocationEvent(obj, size); |
| UnalignedSlot current(address); |
| UnalignedSlot limit(address + size); |
| |
| if (ReadData(current, limit, space_number, address)) { |
| // Only post process if object content has not been deferred. |
| obj = PostProcessNewObject(obj, space_number); |
| } |
| |
| #ifdef DEBUG |
| if (obj->IsCode()) { |
| DCHECK(space_number == CODE_SPACE || space_number == CODE_LO_SPACE); |
| } else { |
| DCHECK(space_number != CODE_SPACE && space_number != CODE_LO_SPACE); |
| } |
| #endif // DEBUG |
| return obj; |
| } |
| |
| void Deserializer::ReadCodeObjectBody(int space_number, |
| 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. |
| UnalignedSlot current(code_object_address + HeapObject::kHeaderSize); |
| UnalignedSlot limit(code_object_address + Code::kDataStart); |
| bool filled = ReadData(current, limit, space_number, 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(data == kInternalReference || data == kInternalReferenceEncoded); |
| |
| // Internal reference address is not encoded via skip, but by offset |
| // from code entry. |
| int pc_offset = source_.GetInt(); |
| int target_offset = source_.GetInt(); |
| DCHECK(0 <= pc_offset && pc_offset <= host->raw_instruction_size()); |
| DCHECK(0 <= target_offset && target_offset <= host->raw_instruction_size()); |
| Address pc = host->entry() + pc_offset; |
| // TODO(ishell): don't encode pc_offset as it can be taken from the rinfo. |
| DCHECK_EQ(pc, rinfo->pc()); |
| Address target = host->entry() + target_offset; |
| Assembler::deserialization_set_target_internal_reference_at( |
| pc, target, |
| data == kInternalReference ? RelocInfo::INTERNAL_REFERENCE |
| : RelocInfo::INTERNAL_REFERENCE_ENCODED); |
| } |
| |
| 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); |
| } |
| } |
| |
| UnalignedSlot Deserializer::ReadRepeatedObject(UnalignedSlot current, |
| int repeat_count) { |
| CHECK_LE(2, repeat_count); |
| |
| HeapObject object = ReadObject(); |
| DCHECK(!Heap::InYoungGeneration(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. |
| UnalignedCopy(current, object.ptr()); |
| current.Advance(); |
| } |
| 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"); |
| } |
| |
| bool Deserializer::ReadData(UnalignedSlot current, UnalignedSlot limit, |
| int 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 != NEW_SPACE && |
| source_space != CODE_SPACE); |
| while (current < limit) { |
| byte data = source_.Get(); |
| switch (data) { |
| #define CASE_STATEMENT(where, space_number) \ |
| case where + space_number: \ |
| STATIC_ASSERT((where & ~kWhereMask) == 0); \ |
| STATIC_ASSERT((space_number & ~kSpaceMask) == 0); |
| |
| #define CASE_BODY(where, space_number_if_any) \ |
| current = ReadDataCase<where, 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(where) \ |
| CASE_STATEMENT(where, NEW_SPACE) \ |
| CASE_BODY(where, NEW_SPACE) \ |
| CASE_STATEMENT(where, OLD_SPACE) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(where, CODE_SPACE) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(where, MAP_SPACE) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(where, LO_SPACE) \ |
| V8_FALLTHROUGH; \ |
| CASE_STATEMENT(where, RO_SPACE) \ |
| CASE_BODY(where, 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(where, space) \ |
| CASE_STATEMENT(where, space) \ |
| CASE_BODY(where, 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, RO_SPACE) |
| // Find an object in the partial snapshots cache and write a pointer to it |
| // to the current object. |
| SINGLE_CASE(kPartialSnapshotCache, RO_SPACE) |
| // Find an object in the partial snapshots cache and write a pointer to it |
| // to the current object. |
| SINGLE_CASE(kReadOnlyObjectCache, RO_SPACE) |
| // Find an object in the attached references and write a pointer to it to |
| // the current object. |
| SINGLE_CASE(kAttachedReference, RO_SPACE) |
| |
| #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(); |
| UnalignedCopy(current, address); |
| current.Advance(); |
| break; |
| } |
| |
| case kInternalReferenceEncoded: |
| 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<AllocationSpace>(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(); |
| byte* raw_data_out = reinterpret_cast<byte*>(current.address()); |
| source_.CopyRaw(raw_data_out, size_in_bytes); |
| current.Advance(size_in_bytes); |
| break; |
| } |
| |
| // Deserialize raw code directly into the body of the code object. |
| // Do not move current. |
| 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(); |
| source_.CopyRaw( |
| reinterpret_cast<byte*>(current_object_address + Code::kDataStart), |
| size_in_bytes); |
| ReadCodeObjectBody(source_space, current_object_address); |
| // Set current to the code object end. |
| current.Advance(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); |
| } |
| UnalignedCopy(current, address); |
| current.Advance(); |
| break; |
| } |
| |
| case kClearedWeakReference: |
| UnalignedCopy(current, HeapObjectReference::ClearedValue(isolate_)); |
| current.Advance(); |
| 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)); |
| UnalignedCopy(current, object); |
| current.Advance(); |
| 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); |
| } |
| |
| UnalignedCopy(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.Advance(); |
| break; |
| } |
| |
| // Deserialize raw data of fixed length from 1 to 32 words. |
| STATIC_ASSERT(kNumberOfFixedRawData == 32); |
| SIXTEEN_CASES(kFixedRawData) |
| SIXTEEN_CASES(kFixedRawData + 16) { |
| byte* raw_data_out = reinterpret_cast<byte*>(current.address()); |
| int size_in_bytes = (data - kFixedRawDataStart) << kPointerSizeLog2; |
| source_.CopyRaw(raw_data_out, size_in_bytes); |
| current.Advance(size_in_bytes); |
| 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 external_reference_table_->address(reference_id); |
| } |
| |
| template <SerializerDeserializer::Where where, int space_number_if_any> |
| UnalignedSlot Deserializer::ReadDataCase(Isolate* isolate, |
| UnalignedSlot current, |
| Address current_object_address, |
| byte data, bool write_barrier_needed) { |
| bool emit_write_barrier = false; |
| int space_number = space_number_if_any == kAnyOldSpace ? (data & kSpaceMask) |
| : space_number_if_any; |
| HeapObject heap_object; |
| HeapObjectReferenceType reference_type = |
| allocator()->GetAndClearNextReferenceIsWeak() |
| ? HeapObjectReferenceType::WEAK |
| : HeapObjectReferenceType::STRONG; |
| |
| if (where == kNewObject) { |
| heap_object = ReadObject(space_number); |
| emit_write_barrier = (space_number == NEW_SPACE); |
| } else if (where == kBackref) { |
| emit_write_barrier = (space_number == NEW_SPACE); |
| heap_object = GetBackReferencedObject(data & kSpaceMask); |
| } else if (where == 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 (where == kReadOnlyObjectCache) { |
| int cache_index = source_.GetInt(); |
| heap_object = |
| HeapObject::cast(isolate->read_only_object_cache()->at(cache_index)); |
| DCHECK(!Heap::InYoungGeneration(heap_object)); |
| emit_write_barrier = false; |
| } else if (where == 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(where, 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); |
| UnalignedCopy(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); |
| } |
| current.Advance(); |
| return current; |
| } |
| |
| } // namespace internal |
| } // namespace v8 |
