| // 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/api.h" |
| #include "src/assembler-inl.h" |
| #include "src/bootstrapper.h" |
| #include "src/deoptimizer.h" |
| #include "src/external-reference-table.h" |
| #include "src/heap/heap-inl.h" |
| #include "src/isolate.h" |
| #include "src/macro-assembler.h" |
| #include "src/objects-inl.h" |
| #include "src/snapshot/builtin-deserializer.h" |
| #include "src/snapshot/natives.h" |
| #include "src/snapshot/startup-deserializer.h" |
| #include "src/v8.h" |
| #include "src/v8threads.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| void Deserializer::DecodeReservation( |
| Vector<const SerializedData::Reservation> res) { |
| DCHECK_EQ(0, reservations_[NEW_SPACE].size()); |
| STATIC_ASSERT(NEW_SPACE == 0); |
| int current_space = NEW_SPACE; |
| for (auto& r : res) { |
| reservations_[current_space].push_back({r.chunk_size(), NULL, NULL}); |
| if (r.is_last()) current_space++; |
| } |
| DCHECK_EQ(kNumberOfSpaces, current_space); |
| for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) current_chunk_[i] = 0; |
| } |
| |
| void Deserializer::RegisterDeserializedObjectsForBlackAllocation() { |
| isolate_->heap()->RegisterDeserializedObjectsForBlackAllocation( |
| reservations_, deserialized_large_objects_, allocated_maps_); |
| } |
| |
| bool Deserializer::ReserveSpace() { |
| #ifdef DEBUG |
| for (int i = NEW_SPACE; i < kNumberOfSpaces; ++i) { |
| DCHECK(reservations_[i].size() > 0); |
| } |
| #endif // DEBUG |
| DCHECK(allocated_maps_.empty()); |
| if (!isolate_->heap()->ReserveSpace(reservations_, &allocated_maps_)) |
| return false; |
| for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) { |
| high_water_[i] = reservations_[i][0].start; |
| } |
| return true; |
| } |
| |
| // static |
| bool Deserializer::ReserveSpace(StartupDeserializer* startup_deserializer, |
| BuiltinDeserializer* builtin_deserializer) { |
| const int first_space = NEW_SPACE; |
| const int last_space = SerializerDeserializer::kNumberOfSpaces; |
| Isolate* isolate = startup_deserializer->isolate(); |
| |
| // Create a set of merged reservations to reserve space in one go. |
| // The BuiltinDeserializer's reservations are ignored, since our actual |
| // requirements vary based on whether lazy deserialization is enabled. |
| // Instead, we manually determine the required code-space. |
| |
| DCHECK(builtin_deserializer->ReservesOnlyCodeSpace()); |
| Heap::Reservation merged_reservations[kNumberOfSpaces]; |
| for (int i = first_space; i < last_space; i++) { |
| merged_reservations[i] = startup_deserializer->reservations_[i]; |
| } |
| |
| Heap::Reservation builtin_reservations = |
| builtin_deserializer->CreateReservationsForEagerBuiltins(); |
| DCHECK(!builtin_reservations.empty()); |
| |
| for (const auto& c : builtin_reservations) { |
| merged_reservations[CODE_SPACE].push_back(c); |
| } |
| |
| if (!isolate->heap()->ReserveSpace(merged_reservations, |
| &startup_deserializer->allocated_maps_)) { |
| return false; |
| } |
| |
| DisallowHeapAllocation no_allocation; |
| |
| // Distribute the successful allocations between both deserializers. |
| // There's nothing to be done here except for code space. |
| |
| { |
| const int num_builtin_reservations = |
| static_cast<int>(builtin_reservations.size()); |
| for (int i = num_builtin_reservations - 1; i >= 0; i--) { |
| const auto& c = merged_reservations[CODE_SPACE].back(); |
| DCHECK_EQ(c.size, builtin_reservations[i].size); |
| DCHECK_EQ(c.size, c.end - c.start); |
| builtin_reservations[i].start = c.start; |
| builtin_reservations[i].end = c.end; |
| merged_reservations[CODE_SPACE].pop_back(); |
| } |
| |
| builtin_deserializer->InitializeBuiltinsTable(builtin_reservations); |
| } |
| |
| // Write back startup reservations. |
| |
| for (int i = first_space; i < last_space; i++) { |
| startup_deserializer->reservations_[i].swap(merged_reservations[i]); |
| } |
| |
| for (int i = first_space; i < kNumberOfPreallocatedSpaces; i++) { |
| startup_deserializer->high_water_[i] = |
| startup_deserializer->reservations_[i][0].start; |
| builtin_deserializer->high_water_[i] = nullptr; |
| } |
| |
| return true; |
| } |
| |
| bool Deserializer::ReservesOnlyCodeSpace() const { |
| for (int space = NEW_SPACE; space < kNumberOfSpaces; space++) { |
| if (space == CODE_SPACE) continue; |
| const auto& r = reservations_[space]; |
| for (const Heap::Chunk& c : r) |
| if (c.size != 0) return false; |
| } |
| return true; |
| } |
| |
| void Deserializer::Initialize(Isolate* isolate) { |
| DCHECK_NULL(isolate_); |
| DCHECK_NOT_NULL(isolate); |
| isolate_ = isolate; |
| DCHECK_NULL(external_reference_table_); |
| external_reference_table_ = ExternalReferenceTable::instance(isolate); |
| #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::ComputeMagicNumber(external_reference_table_)); |
| } |
| |
| void Deserializer::SortMapDescriptors() { |
| for (const auto& address : allocated_maps_) { |
| Map* map = Map::cast(HeapObject::FromAddress(address)); |
| if (map->instance_descriptors()->number_of_descriptors() > 1) { |
| map->instance_descriptors()->Sort(); |
| } |
| } |
| } |
| |
| bool Deserializer::IsLazyDeserializationEnabled() const { |
| return FLAG_lazy_deserialization && !isolate()->serializer_enabled(); |
| } |
| |
| 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()); |
| for (int space = 0; space < kNumberOfPreallocatedSpaces; space++) { |
| int chunk_index = current_chunk_[space]; |
| DCHECK_EQ(reservations_[space].size(), chunk_index + 1); |
| DCHECK_EQ(reservations_[space][chunk_index].end, high_water_[space]); |
| } |
| DCHECK_EQ(allocated_maps_.size(), next_map_index_); |
| #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, Object** start, Object** end) { |
| // The space must be new space. Any other space would cause ReadChunk to try |
| // to update the remembered using NULL as the address. |
| ReadData(start, end, NEW_SPACE, NULL); |
| } |
| |
| void Deserializer::Synchronize(VisitorSynchronization::SyncTag tag) { |
| static const byte expected = kSynchronize; |
| CHECK_EQ(expected, source_.Get()); |
| deserializing_builtins_ = (tag == VisitorSynchronization::kHandleScope); |
| } |
| |
| void Deserializer::DeserializeDeferredObjects() { |
| for (int code = source_.Get(); code != kSynchronize; code = source_.Get()) { |
| switch (code) { |
| case kAlignmentPrefix: |
| case kAlignmentPrefix + 1: |
| case kAlignmentPrefix + 2: |
| SetAlignment(code); |
| break; |
| default: { |
| int space = code & kSpaceMask; |
| DCHECK(space <= kNumberOfSpaces); |
| DCHECK(code - space == kNewObject); |
| HeapObject* object = GetBackReferencedObject(space); |
| int size = source_.GetInt() << kPointerSizeLog2; |
| Address obj_address = object->address(); |
| Object** start = reinterpret_cast<Object**>(obj_address + kPointerSize); |
| Object** end = reinterpret_cast<Object**>(obj_address + size); |
| bool filled = ReadData(start, end, space, obj_address); |
| CHECK(filled); |
| DCHECK(CanBeDeferred(object)); |
| PostProcessNewObject(object, space); |
| } |
| } |
| } |
| } |
| |
| 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 (deserializing_user_code()) { |
| if (obj->IsString()) { |
| String* string = String::cast(obj); |
| // Uninitialize hash field as the hash seed may have changed. |
| string->set_hash_field(String::kEmptyHashField); |
| 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::LookupKeyIfExists(isolate_, &key); |
| if (canonical == NULL) { |
| new_internalized_strings_.push_back(handle(string)); |
| return string; |
| } else { |
| string->SetForwardedInternalizedString(canonical); |
| return canonical; |
| } |
| } |
| } else if (obj->IsScript()) { |
| new_scripts_.push_back(handle(Script::cast(obj))); |
| } else { |
| DCHECK(CanBeDeferred(obj)); |
| } |
| } |
| if (obj->IsAllocationSite()) { |
| // Allocation sites are present in the snapshot, and must be linked into |
| // a list at deserialization time. |
| AllocationSite* site = AllocationSite::cast(obj); |
| // TODO(mvstanton): consider treating the heap()->allocation_sites_list() |
| // as a (weak) root. If this root is relocated correctly, this becomes |
| // unnecessary. |
| if (isolate_->heap()->allocation_sites_list() == Smi::kZero) { |
| site->set_weak_next(isolate_->heap()->undefined_value()); |
| } else { |
| site->set_weak_next(isolate_->heap()->allocation_sites_list()); |
| } |
| isolate_->heap()->set_allocation_sites_list(site); |
| } else if (obj->IsCode()) { |
| // We flush all code pages after deserializing the startup snapshot. In that |
| // case, we only need to remember code objects in the large object space. |
| // When deserializing user code, remember each individual code object. |
| if (deserializing_user_code() || space == LO_SPACE) { |
| new_code_objects_.push_back(Code::cast(obj)); |
| } |
| } else if (obj->IsAccessorInfo()) { |
| if (isolate_->external_reference_redirector()) { |
| accessor_infos_.push_back(AccessorInfo::cast(obj)); |
| } |
| } else if (obj->IsExternalOneByteString()) { |
| DCHECK(obj->map() == isolate_->heap()->native_source_string_map()); |
| ExternalOneByteString* string = ExternalOneByteString::cast(obj); |
| DCHECK(string->is_short()); |
| string->set_resource( |
| NativesExternalStringResource::DecodeForDeserialization( |
| string->resource())); |
| isolate_->heap()->RegisterExternalString(string); |
| } 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<Smi*>(buffer->backing_store()); |
| void* backing_store = off_heap_backing_stores_[store_index->value()]; |
| |
| buffer->set_backing_store(backing_store); |
| buffer->set_allocation_base(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() == nullptr) { |
| Smi* store_index = reinterpret_cast<Smi*>(fta->external_pointer()); |
| void* backing_store = off_heap_backing_stores_[store_index->value()]; |
| |
| fta->set_external_pointer(backing_store); |
| } |
| } |
| if (FLAG_rehash_snapshot && can_rehash_ && !deserializing_user_code()) { |
| if (obj->IsString()) { |
| // Uninitialize hash field as we are going to reinitialize the hash seed. |
| String* string = String::cast(obj); |
| string->set_hash_field(String::kEmptyHashField); |
| } else if (obj->IsTransitionArray() && |
| TransitionArray::cast(obj)->number_of_entries() > 1) { |
| transition_arrays_.push_back(TransitionArray::cast(obj)); |
| } |
| } |
| // Check alignment. |
| DCHECK_EQ(0, Heap::GetFillToAlign(obj->address(), obj->RequiredAlignment())); |
| return obj; |
| } |
| |
| int Deserializer::MaybeReplaceWithDeserializeLazy(int builtin_id) { |
| DCHECK(Builtins::IsBuiltinId(builtin_id)); |
| return (IsLazyDeserializationEnabled() && Builtins::IsLazy(builtin_id) && |
| !deserializing_builtins_) |
| ? Builtins::kDeserializeLazy |
| : builtin_id; |
| } |
| |
| HeapObject* Deserializer::GetBackReferencedObject(int space) { |
| HeapObject* obj; |
| SerializerReference back_reference = |
| SerializerReference::FromBitfield(source_.GetInt()); |
| if (space == LO_SPACE) { |
| uint32_t index = back_reference.large_object_index(); |
| obj = deserialized_large_objects_[index]; |
| } else if (space == MAP_SPACE) { |
| int index = back_reference.map_index(); |
| DCHECK(index < next_map_index_); |
| obj = HeapObject::FromAddress(allocated_maps_[index]); |
| } else { |
| DCHECK(space < kNumberOfPreallocatedSpaces); |
| uint32_t chunk_index = back_reference.chunk_index(); |
| DCHECK_LE(chunk_index, current_chunk_[space]); |
| uint32_t chunk_offset = back_reference.chunk_offset(); |
| Address address = reservations_[space][chunk_index].start + chunk_offset; |
| if (next_alignment_ != kWordAligned) { |
| int padding = Heap::GetFillToAlign(address, next_alignment_); |
| next_alignment_ = kWordAligned; |
| DCHECK(padding == 0 || HeapObject::FromAddress(address)->IsFiller()); |
| address += padding; |
| } |
| obj = HeapObject::FromAddress(address); |
| } |
| if (deserializing_user_code() && obj->IsInternalizedString()) { |
| obj = String::cast(obj)->GetForwardedInternalizedString(); |
| } |
| hot_objects_.Add(obj); |
| return obj; |
| } |
| |
| // This routine writes the new object into the pointer provided and then |
| // returns true if the new object was in young space and false otherwise. |
| // The reason for this strange interface is that otherwise the object is |
| // written very late, which means the FreeSpace map is not set up by the |
| // time we need to use it to mark the space at the end of a page free. |
| void Deserializer::ReadObject(int space_number, Object** write_back) { |
| Address address; |
| HeapObject* obj; |
| int size = source_.GetInt() << kObjectAlignmentBits; |
| |
| if (next_alignment_ != kWordAligned) { |
| int reserved = size + Heap::GetMaximumFillToAlign(next_alignment_); |
| address = Allocate(space_number, reserved); |
| obj = HeapObject::FromAddress(address); |
| // If one of the following assertions fails, then we are deserializing an |
| // aligned object when the filler maps have not been deserialized yet. |
| // We require filler maps as padding to align the object. |
| Heap* heap = isolate_->heap(); |
| DCHECK(heap->free_space_map()->IsMap()); |
| DCHECK(heap->one_pointer_filler_map()->IsMap()); |
| DCHECK(heap->two_pointer_filler_map()->IsMap()); |
| obj = heap->AlignWithFiller(obj, size, reserved, next_alignment_); |
| address = obj->address(); |
| next_alignment_ = kWordAligned; |
| } else { |
| address = Allocate(space_number, size); |
| obj = HeapObject::FromAddress(address); |
| } |
| |
| isolate_->heap()->OnAllocationEvent(obj, size); |
| Object** current = reinterpret_cast<Object**>(address); |
| Object** limit = current + (size >> kPointerSizeLog2); |
| |
| if (ReadData(current, limit, space_number, address)) { |
| // Only post process if object content has not been deferred. |
| obj = PostProcessNewObject(obj, space_number); |
| } |
| |
| Object* write_back_obj = obj; |
| UnalignedCopy(write_back, &write_back_obj); |
| #ifdef DEBUG |
| if (obj->IsCode()) { |
| DCHECK(space_number == CODE_SPACE || space_number == LO_SPACE); |
| } else { |
| DCHECK(space_number != CODE_SPACE); |
| } |
| #endif // DEBUG |
| } |
| |
| // We know the space requirements before deserialization and can |
| // pre-allocate that reserved space. During deserialization, all we need |
| // to do is to bump up the pointer for each space in the reserved |
| // space. This is also used for fixing back references. |
| // We may have to split up the pre-allocation into several chunks |
| // because it would not fit onto a single page. We do not have to keep |
| // track of when to move to the next chunk. An opcode will signal this. |
| // Since multiple large objects cannot be folded into one large object |
| // space allocation, we have to do an actual allocation when deserializing |
| // each large object. Instead of tracking offset for back references, we |
| // reference large objects by index. |
| Address Deserializer::Allocate(int space_index, int size) { |
| if (space_index == LO_SPACE) { |
| AlwaysAllocateScope scope(isolate_); |
| LargeObjectSpace* lo_space = isolate_->heap()->lo_space(); |
| Executability exec = static_cast<Executability>(source_.Get()); |
| AllocationResult result = lo_space->AllocateRaw(size, exec); |
| HeapObject* obj = result.ToObjectChecked(); |
| deserialized_large_objects_.push_back(obj); |
| return obj->address(); |
| } else if (space_index == MAP_SPACE) { |
| DCHECK_EQ(Map::kSize, size); |
| return allocated_maps_[next_map_index_++]; |
| } else { |
| DCHECK(space_index < kNumberOfPreallocatedSpaces); |
| Address address = high_water_[space_index]; |
| DCHECK_NOT_NULL(address); |
| high_water_[space_index] += size; |
| #ifdef DEBUG |
| // Assert that the current reserved chunk is still big enough. |
| const Heap::Reservation& reservation = reservations_[space_index]; |
| int chunk_index = current_chunk_[space_index]; |
| DCHECK_LE(high_water_[space_index], reservation[chunk_index].end); |
| #endif |
| if (space_index == CODE_SPACE) SkipList::Update(address, size); |
| return address; |
| } |
| } |
| |
| Object* Deserializer::ReadDataSingle() { |
| Object* o; |
| Object** start = &o; |
| Object** end = start + 1; |
| int source_space = NEW_SPACE; |
| Address current_object = nullptr; |
| |
| CHECK(ReadData(start, end, source_space, current_object)); |
| |
| return o; |
| } |
| |
| bool Deserializer::ReadData(Object** current, Object** 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 != NULL && source_space != NEW_SPACE && |
| source_space != CODE_SPACE); |
| while (current < limit) { |
| byte data = source_.Get(); |
| switch (data) { |
| #define CASE_STATEMENT(where, how, within, space_number) \ |
| case where + how + within + space_number: \ |
| STATIC_ASSERT((where & ~kWhereMask) == 0); \ |
| STATIC_ASSERT((how & ~kHowToCodeMask) == 0); \ |
| STATIC_ASSERT((within & ~kWhereToPointMask) == 0); \ |
| STATIC_ASSERT((space_number & ~kSpaceMask) == 0); |
| |
| #define CASE_BODY(where, how, within, space_number_if_any) \ |
| current = ReadDataCase<where, how, within, 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, how, within) \ |
| CASE_STATEMENT(where, how, within, NEW_SPACE) \ |
| CASE_BODY(where, how, within, NEW_SPACE) \ |
| CASE_STATEMENT(where, how, within, OLD_SPACE) \ |
| CASE_STATEMENT(where, how, within, CODE_SPACE) \ |
| CASE_STATEMENT(where, how, within, MAP_SPACE) \ |
| CASE_STATEMENT(where, how, within, LO_SPACE) \ |
| CASE_BODY(where, how, within, 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, how, within, space) \ |
| CASE_STATEMENT(where, how, within, space) \ |
| CASE_BODY(where, how, within, space) |
| |
| // Deserialize a new object and write a pointer to it to the current |
| // object. |
| ALL_SPACES(kNewObject, kPlain, kStartOfObject) |
| // Deserialize a new code object and write a pointer to its first |
| // instruction to the current code object. |
| ALL_SPACES(kNewObject, kFromCode, kInnerPointer) |
| // 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, kPlain, kStartOfObject) |
| ALL_SPACES(kBackrefWithSkip, kPlain, kStartOfObject) |
| #if V8_CODE_EMBEDS_OBJECT_POINTER |
| // Deserialize a new object from pointer found in code and write |
| // a pointer to it to the current object. Required only for MIPS, PPC, ARM |
| // or S390 with embedded constant pool, and omitted on the other |
| // architectures because it is fully unrolled and would cause bloat. |
| ALL_SPACES(kNewObject, kFromCode, kStartOfObject) |
| // Find a recently deserialized code object using its offset from the |
| // current allocation point and write a pointer to it to the current |
| // object. Required only for MIPS, PPC, ARM or S390 with embedded |
| // constant pool. |
| ALL_SPACES(kBackref, kFromCode, kStartOfObject) |
| ALL_SPACES(kBackrefWithSkip, kFromCode, kStartOfObject) |
| #endif |
| // Find a recently deserialized code object using its offset from the |
| // current allocation point and write a pointer to its first instruction |
| // to the current code object or the instruction pointer in a function |
| // object. |
| ALL_SPACES(kBackref, kFromCode, kInnerPointer) |
| ALL_SPACES(kBackrefWithSkip, kFromCode, kInnerPointer) |
| // Find an object in the roots array and write a pointer to it to the |
| // current object. |
| SINGLE_CASE(kRootArray, kPlain, kStartOfObject, 0) |
| #if V8_CODE_EMBEDS_OBJECT_POINTER |
| // Find an object in the roots array and write a pointer to it to in code. |
| SINGLE_CASE(kRootArray, kFromCode, kStartOfObject, 0) |
| #endif |
| // Find an object in the partial snapshots cache and write a pointer to it |
| // to the current object. |
| SINGLE_CASE(kPartialSnapshotCache, kPlain, kStartOfObject, 0) |
| SINGLE_CASE(kPartialSnapshotCache, kFromCode, kStartOfObject, 0) |
| SINGLE_CASE(kPartialSnapshotCache, kFromCode, kInnerPointer, 0) |
| // Find an external reference and write a pointer to it to the current |
| // object. |
| SINGLE_CASE(kExternalReference, kPlain, kStartOfObject, 0) |
| // Find an external reference and write a pointer to it in the current |
| // code object. |
| SINGLE_CASE(kExternalReference, kFromCode, kStartOfObject, 0) |
| // Find an object in the attached references and write a pointer to it to |
| // the current object. |
| SINGLE_CASE(kAttachedReference, kPlain, kStartOfObject, 0) |
| SINGLE_CASE(kAttachedReference, kFromCode, kStartOfObject, 0) |
| SINGLE_CASE(kAttachedReference, kFromCode, kInnerPointer, 0) |
| // Find a builtin and write a pointer to it to the current object. |
| SINGLE_CASE(kBuiltin, kPlain, kStartOfObject, 0) |
| SINGLE_CASE(kBuiltin, kFromCode, kStartOfObject, 0) |
| SINGLE_CASE(kBuiltin, kFromCode, kInnerPointer, 0) |
| |
| #undef CASE_STATEMENT |
| #undef CASE_BODY |
| #undef ALL_SPACES |
| |
| case kSkip: { |
| int size = source_.GetInt(); |
| current = reinterpret_cast<Object**>( |
| reinterpret_cast<intptr_t>(current) + size); |
| break; |
| } |
| |
| case kInternalReferenceEncoded: |
| case kInternalReference: { |
| // Internal reference address is not encoded via skip, but by offset |
| // from code entry. |
| int pc_offset = source_.GetInt(); |
| int target_offset = source_.GetInt(); |
| Code* code = |
| Code::cast(HeapObject::FromAddress(current_object_address)); |
| DCHECK(0 <= pc_offset && pc_offset <= code->instruction_size()); |
| DCHECK(0 <= target_offset && target_offset <= code->instruction_size()); |
| Address pc = code->entry() + pc_offset; |
| Address target = code->entry() + target_offset; |
| Assembler::deserialization_set_target_internal_reference_at( |
| isolate, pc, target, data == kInternalReference |
| ? RelocInfo::INTERNAL_REFERENCE |
| : RelocInfo::INTERNAL_REFERENCE_ENCODED); |
| break; |
| } |
| |
| case kNop: |
| break; |
| |
| case kNextChunk: { |
| int space = source_.Get(); |
| DCHECK(space < kNumberOfPreallocatedSpaces); |
| int chunk_index = current_chunk_[space]; |
| const Heap::Reservation& reservation = reservations_[space]; |
| // Make sure the current chunk is indeed exhausted. |
| CHECK_EQ(reservation[chunk_index].end, high_water_[space]); |
| // Move to next reserved chunk. |
| chunk_index = ++current_chunk_[space]; |
| CHECK_LT(chunk_index, reservation.size()); |
| high_water_[space] = reservation[chunk_index].start; |
| break; |
| } |
| |
| case kDeferred: { |
| // Deferred can only occur right after the heap object header. |
| DCHECK(current == reinterpret_cast<Object**>(current_object_address + |
| kPointerSize)); |
| 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. |
| CHECK(false); |
| break; |
| |
| // Deserialize raw data of variable length. |
| case kVariableRawData: { |
| int size_in_bytes = source_.GetInt(); |
| byte* raw_data_out = reinterpret_cast<byte*>(current); |
| source_.CopyRaw(raw_data_out, size_in_bytes); |
| current = reinterpret_cast<Object**>( |
| reinterpret_cast<intptr_t>(current) + size_in_bytes); |
| break; |
| } |
| |
| // Deserialize raw code directly into the body of the code object. |
| // Do not move current. |
| case kVariableRawCode: { |
| int size_in_bytes = source_.GetInt(); |
| source_.CopyRaw(current_object_address + Code::kDataStart, |
| size_in_bytes); |
| break; |
| } |
| |
| case kVariableRepeat: { |
| int repeats = source_.GetInt(); |
| Object* object = current[-1]; |
| DCHECK(!isolate->heap()->InNewSpace(object)); |
| for (int i = 0; i < repeats; i++) UnalignedCopy(current++, &object); |
| 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: { |
| int skip = source_.GetInt(); |
| current = reinterpret_cast<Object**>( |
| reinterpret_cast<Address>(current) + skip); |
| uint32_t reference_id = static_cast<uint32_t>(source_.GetInt()); |
| DCHECK_WITH_MSG(reference_id < num_api_references_, |
| "too few external references provided through the API"); |
| Address address = reinterpret_cast<Address>( |
| isolate->api_external_references()[reference_id]); |
| memcpy(current, &address, kPointerSize); |
| current++; |
| break; |
| } |
| |
| case kAlignmentPrefix: |
| case kAlignmentPrefix + 1: |
| case kAlignmentPrefix + 2: |
| SetAlignment(data); |
| break; |
| |
| STATIC_ASSERT(kNumberOfRootArrayConstants == Heap::kOldSpaceRoots); |
| STATIC_ASSERT(kNumberOfRootArrayConstants == 32); |
| SIXTEEN_CASES(kRootArrayConstantsWithSkip) |
| SIXTEEN_CASES(kRootArrayConstantsWithSkip + 16) { |
| int skip = source_.GetInt(); |
| current = reinterpret_cast<Object**>( |
| reinterpret_cast<intptr_t>(current) + skip); |
| // Fall through. |
| } |
| |
| SIXTEEN_CASES(kRootArrayConstants) |
| SIXTEEN_CASES(kRootArrayConstants + 16) { |
| int id = data & kRootArrayConstantsMask; |
| Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(id); |
| Object* object = isolate->heap()->root(root_index); |
| DCHECK(!isolate->heap()->InNewSpace(object)); |
| UnalignedCopy(current++, &object); |
| break; |
| } |
| |
| STATIC_ASSERT(kNumberOfHotObjects == 8); |
| FOUR_CASES(kHotObjectWithSkip) |
| FOUR_CASES(kHotObjectWithSkip + 4) { |
| int skip = source_.GetInt(); |
| current = reinterpret_cast<Object**>( |
| reinterpret_cast<Address>(current) + skip); |
| // Fall through. |
| } |
| |
| FOUR_CASES(kHotObject) |
| FOUR_CASES(kHotObject + 4) { |
| int index = data & kHotObjectMask; |
| Object* hot_object = hot_objects_.Get(index); |
| UnalignedCopy(current, &hot_object); |
| if (write_barrier_needed && isolate->heap()->InNewSpace(hot_object)) { |
| Address current_address = reinterpret_cast<Address>(current); |
| isolate->heap()->RecordWrite( |
| HeapObject::FromAddress(current_object_address), |
| reinterpret_cast<Object**>(current_address), hot_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) { |
| byte* raw_data_out = reinterpret_cast<byte*>(current); |
| int size_in_bytes = (data - kFixedRawDataStart) << kPointerSizeLog2; |
| source_.CopyRaw(raw_data_out, size_in_bytes); |
| current = reinterpret_cast<Object**>(raw_data_out + size_in_bytes); |
| break; |
| } |
| |
| STATIC_ASSERT(kNumberOfFixedRepeat == 16); |
| SIXTEEN_CASES(kFixedRepeat) { |
| int repeats = data - kFixedRepeatStart; |
| Object* object; |
| UnalignedCopy(&object, current - 1); |
| DCHECK(!isolate->heap()->InNewSpace(object)); |
| for (int i = 0; i < repeats; i++) UnalignedCopy(current++, &object); |
| break; |
| } |
| |
| #undef SIXTEEN_CASES |
| #undef FOUR_CASES |
| #undef SINGLE_CASE |
| |
| default: |
| CHECK(false); |
| } |
| } |
| CHECK_EQ(limit, current); |
| return true; |
| } |
| |
| template <int where, int how, int within, int space_number_if_any> |
| Object** Deserializer::ReadDataCase(Isolate* isolate, Object** current, |
| Address current_object_address, byte data, |
| bool write_barrier_needed) { |
| bool emit_write_barrier = false; |
| bool current_was_incremented = false; |
| int space_number = space_number_if_any == kAnyOldSpace ? (data & kSpaceMask) |
| : space_number_if_any; |
| if (where == kNewObject && how == kPlain && within == kStartOfObject) { |
| ReadObject(space_number, current); |
| emit_write_barrier = (space_number == NEW_SPACE); |
| } else { |
| Object* new_object = NULL; /* May not be a real Object pointer. */ |
| if (where == kNewObject) { |
| ReadObject(space_number, &new_object); |
| } else if (where == kBackref) { |
| emit_write_barrier = (space_number == NEW_SPACE); |
| new_object = GetBackReferencedObject(data & kSpaceMask); |
| } else if (where == kBackrefWithSkip) { |
| int skip = source_.GetInt(); |
| current = |
| reinterpret_cast<Object**>(reinterpret_cast<Address>(current) + skip); |
| emit_write_barrier = (space_number == NEW_SPACE); |
| new_object = GetBackReferencedObject(data & kSpaceMask); |
| } else if (where == kRootArray) { |
| int id = source_.GetInt(); |
| Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(id); |
| new_object = isolate->heap()->root(root_index); |
| emit_write_barrier = isolate->heap()->InNewSpace(new_object); |
| hot_objects_.Add(HeapObject::cast(new_object)); |
| } else if (where == kPartialSnapshotCache) { |
| int cache_index = source_.GetInt(); |
| new_object = isolate->partial_snapshot_cache()->at(cache_index); |
| emit_write_barrier = isolate->heap()->InNewSpace(new_object); |
| } else if (where == kExternalReference) { |
| int skip = source_.GetInt(); |
| current = |
| reinterpret_cast<Object**>(reinterpret_cast<Address>(current) + skip); |
| uint32_t reference_id = static_cast<uint32_t>(source_.GetInt()); |
| Address address = external_reference_table_->address(reference_id); |
| new_object = reinterpret_cast<Object*>(address); |
| } else if (where == kAttachedReference) { |
| int index = source_.GetInt(); |
| new_object = *attached_objects_[index]; |
| emit_write_barrier = isolate->heap()->InNewSpace(new_object); |
| } else { |
| DCHECK(where == kBuiltin); |
| int builtin_id = MaybeReplaceWithDeserializeLazy(source_.GetInt()); |
| new_object = isolate->builtins()->builtin(builtin_id); |
| emit_write_barrier = false; |
| } |
| if (within == kInnerPointer) { |
| DCHECK(how == kFromCode); |
| if (where == kBuiltin) { |
| // At this point, new_object may still be uninitialized, thus the |
| // unchecked Code cast. |
| new_object = reinterpret_cast<Object*>( |
| reinterpret_cast<Code*>(new_object)->instruction_start()); |
| } else if (new_object->IsCode()) { |
| new_object = reinterpret_cast<Object*>( |
| Code::cast(new_object)->instruction_start()); |
| } else { |
| Cell* cell = Cell::cast(new_object); |
| new_object = reinterpret_cast<Object*>(cell->ValueAddress()); |
| } |
| } |
| if (how == kFromCode) { |
| Address location_of_branch_data = reinterpret_cast<Address>(current); |
| Assembler::deserialization_set_special_target_at( |
| isolate, location_of_branch_data, |
| Code::cast(HeapObject::FromAddress(current_object_address)), |
| reinterpret_cast<Address>(new_object)); |
| location_of_branch_data += Assembler::kSpecialTargetSize; |
| current = reinterpret_cast<Object**>(location_of_branch_data); |
| current_was_incremented = true; |
| } else { |
| UnalignedCopy(current, &new_object); |
| } |
| } |
| if (emit_write_barrier && write_barrier_needed) { |
| Address current_address = reinterpret_cast<Address>(current); |
| SLOW_DCHECK(isolate->heap()->ContainsSlow(current_object_address)); |
| isolate->heap()->RecordWrite( |
| HeapObject::FromAddress(current_object_address), |
| reinterpret_cast<Object**>(current_address), |
| *reinterpret_cast<Object**>(current_address)); |
| } |
| if (!current_was_incremented) { |
| current++; |
| } |
| |
| return current; |
| } |
| |
| } // namespace internal |
| } // namespace v8 |