// 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/code-serializer.h" #include "src/base/platform/platform.h" #include "src/codegen/macro-assembler.h" #include "src/common/globals.h" #include "src/debug/debug.h" #include "src/heap/heap-inl.h" #include "src/heap/off-thread-factory-inl.h" #include "src/logging/counters.h" #include "src/logging/log.h" #include "src/objects/objects-inl.h" #include "src/objects/slots.h" #include "src/objects/visitors.h" #include "src/snapshot/object-deserializer.h" #include "src/snapshot/snapshot-utils.h" #include "src/snapshot/snapshot.h" #include "src/utils/version.h" namespace v8 { namespace internal { ScriptData::ScriptData(const byte* data, int length) : owns_data_(false), rejected_(false), data_(data), length_(length) { if (!IsAligned(reinterpret_cast<intptr_t>(data), kPointerAlignment)) { byte* copy = NewArray<byte>(length); DCHECK(IsAligned(reinterpret_cast<intptr_t>(copy), kPointerAlignment)); CopyBytes(copy, data, length); data_ = copy; AcquireDataOwnership(); } } CodeSerializer::CodeSerializer(Isolate* isolate, uint32_t source_hash) : Serializer(isolate, Snapshot::kDefaultSerializerFlags), source_hash_(source_hash) { allocator()->UseCustomChunkSize(FLAG_serialization_chunk_size); } // static ScriptCompiler::CachedData* CodeSerializer::Serialize( Handle<SharedFunctionInfo> info) { Isolate* isolate = info->GetIsolate(); TRACE_EVENT_CALL_STATS_SCOPED(isolate, "v8", "V8.Execute"); HistogramTimerScope histogram_timer(isolate->counters()->compile_serialize()); RuntimeCallTimerScope runtimeTimer(isolate, RuntimeCallCounterId::kCompileSerialize); TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.CompileSerialize"); base::ElapsedTimer timer; if (FLAG_profile_deserialization) timer.Start(); Handle<Script> script(Script::cast(info->script()), isolate); if (FLAG_trace_serializer) { PrintF("[Serializing from"); script->name().ShortPrint(); PrintF("]\n"); } // TODO(7110): Enable serialization of Asm modules once the AsmWasmData is // context independent. if (script->ContainsAsmModule()) return nullptr; // Serialize code object. Handle<String> source(String::cast(script->source()), isolate); CodeSerializer cs(isolate, SerializedCodeData::SourceHash( source, script->origin_options())); DisallowHeapAllocation no_gc; cs.reference_map()->AddAttachedReference( reinterpret_cast<void*>(source->ptr())); ScriptData* script_data = cs.SerializeSharedFunctionInfo(info); if (FLAG_profile_deserialization) { double ms = timer.Elapsed().InMillisecondsF(); int length = script_data->length(); PrintF("[Serializing to %d bytes took %0.3f ms]\n", length, ms); } ScriptCompiler::CachedData* result = new ScriptCompiler::CachedData(script_data->data(), script_data->length(), ScriptCompiler::CachedData::BufferOwned); script_data->ReleaseDataOwnership(); delete script_data; return result; } ScriptData* CodeSerializer::SerializeSharedFunctionInfo( Handle<SharedFunctionInfo> info) { DisallowHeapAllocation no_gc; VisitRootPointer(Root::kHandleScope, nullptr, FullObjectSlot(info.location())); SerializeDeferredObjects(); Pad(); SerializedCodeData data(sink_.data(), this); return data.GetScriptData(); } bool CodeSerializer::SerializeReadOnlyObject(HeapObject obj) { if (!ReadOnlyHeap::Contains(obj)) return false; // For objects on the read-only heap, never serialize the object, but instead // create a back reference that encodes the page number as the chunk_index and // the offset within the page as the chunk_offset. Address address = obj.address(); BasicMemoryChunk* chunk = BasicMemoryChunk::FromAddress(address); uint32_t chunk_index = 0; ReadOnlySpace* const read_only_space = isolate()->heap()->read_only_space(); for (ReadOnlyPage* page : read_only_space->pages()) { if (chunk == page) break; ++chunk_index; } uint32_t chunk_offset = static_cast<uint32_t>(chunk->Offset(address)); SerializerReference back_reference = SerializerReference::BackReference( SnapshotSpace::kReadOnlyHeap, chunk_index, chunk_offset); reference_map()->Add(reinterpret_cast<void*>(obj.ptr()), back_reference); CHECK(SerializeBackReference(obj)); return true; } void CodeSerializer::SerializeObject(HeapObject obj) { if (SerializeHotObject(obj)) return; if (SerializeRoot(obj)) return; if (SerializeBackReference(obj)) return; if (SerializeReadOnlyObject(obj)) return; CHECK(!obj.IsCode()); ReadOnlyRoots roots(isolate()); if (ElideObject(obj)) { return SerializeObject(roots.undefined_value()); } if (obj.IsScript()) { Script script_obj = Script::cast(obj); DCHECK_NE(script_obj.compilation_type(), Script::COMPILATION_TYPE_EVAL); // We want to differentiate between undefined and uninitialized_symbol for // context_data for now. It is hack to allow debugging for scripts that are // included as a part of custom snapshot. (see debug::Script::IsEmbedded()) Object context_data = script_obj.context_data(); if (context_data != roots.undefined_value() && context_data != roots.uninitialized_symbol()) { script_obj.set_context_data(roots.undefined_value()); } // We don't want to serialize host options to avoid serializing unnecessary // object graph. FixedArray host_options = script_obj.host_defined_options(); script_obj.set_host_defined_options(roots.empty_fixed_array()); SerializeGeneric(obj); script_obj.set_host_defined_options(host_options); script_obj.set_context_data(context_data); return; } if (obj.IsSharedFunctionInfo()) { SharedFunctionInfo sfi = SharedFunctionInfo::cast(obj); // TODO(7110): Enable serializing of Asm modules once the AsmWasmData // is context independent. DCHECK(!sfi.IsApiFunction() && !sfi.HasAsmWasmData()); DebugInfo debug_info; BytecodeArray debug_bytecode_array; if (sfi.HasDebugInfo()) { // Clear debug info. debug_info = sfi.GetDebugInfo(); if (debug_info.HasInstrumentedBytecodeArray()) { debug_bytecode_array = debug_info.DebugBytecodeArray(); sfi.SetDebugBytecodeArray(debug_info.OriginalBytecodeArray()); } sfi.set_script_or_debug_info(debug_info.script()); } DCHECK(!sfi.HasDebugInfo()); SerializeGeneric(obj); // Restore debug info if (!debug_info.is_null()) { sfi.set_script_or_debug_info(debug_info); if (!debug_bytecode_array.is_null()) { sfi.SetDebugBytecodeArray(debug_bytecode_array); } } return; } // NOTE(mmarchini): If we try to serialize an InterpreterData our process // will crash since it stores a code object. Instead, we serialize the // bytecode array stored within the InterpreterData, which is the important // information. On deserialization we'll create our code objects again, if // --interpreted-frames-native-stack is on. See v8:9122 for more context #ifndef V8_TARGET_ARCH_ARM if (V8_UNLIKELY(FLAG_interpreted_frames_native_stack) && obj.IsInterpreterData()) { obj = InterpreterData::cast(obj).bytecode_array(); } #endif // V8_TARGET_ARCH_ARM // Past this point we should not see any (context-specific) maps anymore. CHECK(!obj.IsMap()); // There should be no references to the global object embedded. CHECK(!obj.IsJSGlobalProxy() && !obj.IsJSGlobalObject()); // Embedded FixedArrays that need rehashing must support rehashing. CHECK_IMPLIES(obj.NeedsRehashing(), obj.CanBeRehashed()); // We expect no instantiated function objects or contexts. CHECK(!obj.IsJSFunction() && !obj.IsContext()); SerializeGeneric(obj); } void CodeSerializer::SerializeGeneric(HeapObject heap_object) { // Object has not yet been serialized. Serialize it here. ObjectSerializer serializer(this, heap_object, &sink_); serializer.Serialize(); } #ifndef V8_TARGET_ARCH_ARM // NOTE(mmarchini): when FLAG_interpreted_frames_native_stack is on, we want to // create duplicates of InterpreterEntryTrampoline for the deserialized // functions, otherwise we'll call the builtin IET for those functions (which // is not what a user of this flag wants). void CreateInterpreterDataForDeserializedCode(Isolate* isolate, Handle<SharedFunctionInfo> sfi, bool log_code_creation) { Handle<Script> script(Script::cast(sfi->script()), isolate); String name = ReadOnlyRoots(isolate).empty_string(); if (script->name().IsString()) name = String::cast(script->name()); Handle<String> name_handle(name, isolate); SharedFunctionInfo::ScriptIterator iter(isolate, *script); for (SharedFunctionInfo shared_info = iter.Next(); !shared_info.is_null(); shared_info = iter.Next()) { if (!shared_info.HasBytecodeArray()) continue; Handle<SharedFunctionInfo> info = handle(shared_info, isolate); Handle<Code> code = isolate->factory()->CopyCode(Handle<Code>::cast( isolate->factory()->interpreter_entry_trampoline_for_profiling())); Handle<InterpreterData> interpreter_data = Handle<InterpreterData>::cast(isolate->factory()->NewStruct( INTERPRETER_DATA_TYPE, AllocationType::kOld)); interpreter_data->set_bytecode_array(info->GetBytecodeArray()); interpreter_data->set_interpreter_trampoline(*code); info->set_interpreter_data(*interpreter_data); if (!log_code_creation) continue; Handle<AbstractCode> abstract_code = Handle<AbstractCode>::cast(code); int line_num = script->GetLineNumber(info->StartPosition()) + 1; int column_num = script->GetColumnNumber(info->StartPosition()) + 1; PROFILE(isolate, CodeCreateEvent(CodeEventListener::INTERPRETED_FUNCTION_TAG, abstract_code, info, name_handle, line_num, column_num)); } } #endif // V8_TARGET_ARCH_ARM namespace { class StressOffThreadDeserializeThread final : public base::Thread { public: explicit StressOffThreadDeserializeThread( OffThreadIsolate* off_thread_isolate, const SerializedCodeData* scd) : Thread( base::Thread::Options("StressOffThreadDeserializeThread", 2 * MB)), off_thread_isolate_(off_thread_isolate), scd_(scd) {} MaybeHandle<SharedFunctionInfo> maybe_result() const { return maybe_result_.ToHandle(); } void Run() final { off_thread_isolate_->PinToCurrentThread(); MaybeHandle<SharedFunctionInfo> off_thread_maybe_result = ObjectDeserializer::DeserializeSharedFunctionInfoOffThread( off_thread_isolate_, scd_, off_thread_isolate_->factory()->empty_string()); maybe_result_ = off_thread_isolate_->TransferHandle(off_thread_maybe_result); } private: OffThreadIsolate* off_thread_isolate_; const SerializedCodeData* scd_; OffThreadTransferMaybeHandle<SharedFunctionInfo> maybe_result_; }; } // namespace MaybeHandle<SharedFunctionInfo> CodeSerializer::Deserialize( Isolate* isolate, ScriptData* cached_data, Handle<String> source, ScriptOriginOptions origin_options) { base::ElapsedTimer timer; if (FLAG_profile_deserialization || FLAG_log_function_events) timer.Start(); HandleScope scope(isolate); SerializedCodeData::SanityCheckResult sanity_check_result = SerializedCodeData::CHECK_SUCCESS; const SerializedCodeData scd = SerializedCodeData::FromCachedData( cached_data, SerializedCodeData::SourceHash(source, origin_options), &sanity_check_result); if (sanity_check_result != SerializedCodeData::CHECK_SUCCESS) { if (FLAG_profile_deserialization) PrintF("[Cached code failed check]\n"); DCHECK(cached_data->rejected()); isolate->counters()->code_cache_reject_reason()->AddSample( sanity_check_result); return MaybeHandle<SharedFunctionInfo>(); } // Deserialize. MaybeHandle<SharedFunctionInfo> maybe_result; if (FLAG_stress_background_compile) { Zone zone(isolate->allocator(), "Deserialize"); OffThreadIsolate off_thread_isolate(isolate, &zone); StressOffThreadDeserializeThread thread(&off_thread_isolate, &scd); CHECK(thread.Start()); thread.Join(); off_thread_isolate.FinishOffThread(); off_thread_isolate.Publish(isolate); maybe_result = thread.maybe_result(); // Fix-up result script source. Handle<SharedFunctionInfo> result; if (maybe_result.ToHandle(&result)) { Script::cast(result->script()).set_source(*source); } } else { maybe_result = ObjectDeserializer::DeserializeSharedFunctionInfo( isolate, &scd, source); } Handle<SharedFunctionInfo> result; if (!maybe_result.ToHandle(&result)) { // Deserializing may fail if the reservations cannot be fulfilled. if (FLAG_profile_deserialization) PrintF("[Deserializing failed]\n"); return MaybeHandle<SharedFunctionInfo>(); } if (FLAG_profile_deserialization) { double ms = timer.Elapsed().InMillisecondsF(); int length = cached_data->length(); PrintF("[Deserializing from %d bytes took %0.3f ms]\n", length, ms); } const bool log_code_creation = isolate->logger()->is_listening_to_code_events() || isolate->is_profiling() || isolate->code_event_dispatcher()->IsListeningToCodeEvents(); #ifndef V8_TARGET_ARCH_ARM if (V8_UNLIKELY(FLAG_interpreted_frames_native_stack)) CreateInterpreterDataForDeserializedCode(isolate, result, log_code_creation); #endif // V8_TARGET_ARCH_ARM bool needs_source_positions = isolate->NeedsSourcePositionsForProfiling(); if (log_code_creation || FLAG_log_function_events) { Handle<Script> script(Script::cast(result->script()), isolate); Handle<String> name(script->name().IsString() ? String::cast(script->name()) : ReadOnlyRoots(isolate).empty_string(), isolate); if (FLAG_log_function_events) { LOG(isolate, FunctionEvent("deserialize", script->id(), timer.Elapsed().InMillisecondsF(), result->StartPosition(), result->EndPosition(), *name)); } if (log_code_creation) { Script::InitLineEnds(isolate, script); SharedFunctionInfo::ScriptIterator iter(isolate, *script); for (SharedFunctionInfo info = iter.Next(); !info.is_null(); info = iter.Next()) { if (info.is_compiled()) { Handle<SharedFunctionInfo> shared_info(info, isolate); if (needs_source_positions) { SharedFunctionInfo::EnsureSourcePositionsAvailable(isolate, shared_info); } DisallowHeapAllocation no_gc; int line_num = script->GetLineNumber(shared_info->StartPosition()) + 1; int column_num = script->GetColumnNumber(shared_info->StartPosition()) + 1; PROFILE(isolate, CodeCreateEvent(CodeEventListener::SCRIPT_TAG, handle(shared_info->abstract_code(), isolate), shared_info, name, line_num, column_num)); } } } } if (needs_source_positions) { Handle<Script> script(Script::cast(result->script()), isolate); Script::InitLineEnds(isolate, script); } return scope.CloseAndEscape(result); } SerializedCodeData::SerializedCodeData(const std::vector<byte>* payload, const CodeSerializer* cs) { DisallowHeapAllocation no_gc; std::vector<Reservation> reservations = cs->EncodeReservations(); // Calculate sizes. uint32_t reservation_size = static_cast<uint32_t>(reservations.size()) * kUInt32Size; uint32_t num_stub_keys = 0; // TODO(jgruber): Remove. uint32_t stub_keys_size = num_stub_keys * kUInt32Size; uint32_t payload_offset = kHeaderSize + reservation_size + stub_keys_size; uint32_t padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset); uint32_t size = padded_payload_offset + static_cast<uint32_t>(payload->size()); DCHECK(IsAligned(size, kPointerAlignment)); // Allocate backing store and create result data. AllocateData(size); // Zero out pre-payload data. Part of that is only used for padding. memset(data_, 0, padded_payload_offset); // Set header values. SetMagicNumber(); SetHeaderValue(kVersionHashOffset, Version::Hash()); SetHeaderValue(kSourceHashOffset, cs->source_hash()); SetHeaderValue(kFlagHashOffset, FlagList::Hash()); SetHeaderValue(kNumReservationsOffset, static_cast<uint32_t>(reservations.size())); SetHeaderValue(kPayloadLengthOffset, static_cast<uint32_t>(payload->size())); // Zero out any padding in the header. memset(data_ + kUnalignedHeaderSize, 0, kHeaderSize - kUnalignedHeaderSize); // Copy reservation chunk sizes. CopyBytes(data_ + kHeaderSize, reinterpret_cast<const byte*>(reservations.data()), reservation_size); // Copy serialized data. CopyBytes(data_ + padded_payload_offset, payload->data(), static_cast<size_t>(payload->size())); SetHeaderValue(kChecksumOffset, Checksum(ChecksummedContent())); } SerializedCodeData::SanityCheckResult SerializedCodeData::SanityCheck( uint32_t expected_source_hash) const { if (this->size_ < kHeaderSize) return INVALID_HEADER; uint32_t magic_number = GetMagicNumber(); if (magic_number != kMagicNumber) return MAGIC_NUMBER_MISMATCH; uint32_t version_hash = GetHeaderValue(kVersionHashOffset); uint32_t source_hash = GetHeaderValue(kSourceHashOffset); uint32_t flags_hash = GetHeaderValue(kFlagHashOffset); uint32_t payload_length = GetHeaderValue(kPayloadLengthOffset); uint32_t c = GetHeaderValue(kChecksumOffset); if (version_hash != Version::Hash()) return VERSION_MISMATCH; if (source_hash != expected_source_hash) return SOURCE_MISMATCH; if (flags_hash != FlagList::Hash()) return FLAGS_MISMATCH; uint32_t max_payload_length = this->size_ - POINTER_SIZE_ALIGN(kHeaderSize + GetHeaderValue(kNumReservationsOffset) * kInt32Size); if (payload_length > max_payload_length) return LENGTH_MISMATCH; if (Checksum(ChecksummedContent()) != c) return CHECKSUM_MISMATCH; return CHECK_SUCCESS; } uint32_t SerializedCodeData::SourceHash(Handle<String> source, ScriptOriginOptions origin_options) { const uint32_t source_length = source->length(); static constexpr uint32_t kModuleFlagMask = (1 << 31); const uint32_t is_module = origin_options.IsModule() ? kModuleFlagMask : 0; DCHECK_EQ(0, source_length & kModuleFlagMask); return source_length | is_module; } // Return ScriptData object and relinquish ownership over it to the caller. ScriptData* SerializedCodeData::GetScriptData() { DCHECK(owns_data_); ScriptData* result = new ScriptData(data_, size_); result->AcquireDataOwnership(); owns_data_ = false; data_ = nullptr; return result; } std::vector<SerializedData::Reservation> SerializedCodeData::Reservations() const { uint32_t size = GetHeaderValue(kNumReservationsOffset); std::vector<Reservation> reservations(size); memcpy(reservations.data(), data_ + kHeaderSize, size * sizeof(SerializedData::Reservation)); return reservations; } Vector<const byte> SerializedCodeData::Payload() const { int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size; int payload_offset = kHeaderSize + reservations_size; int padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset); const byte* payload = data_ + padded_payload_offset; DCHECK(IsAligned(reinterpret_cast<intptr_t>(payload), kPointerAlignment)); int length = GetHeaderValue(kPayloadLengthOffset); DCHECK_EQ(data_ + size_, payload + length); return Vector<const byte>(payload, length); } SerializedCodeData::SerializedCodeData(ScriptData* data) : SerializedData(const_cast<byte*>(data->data()), data->length()) {} SerializedCodeData SerializedCodeData::FromCachedData( ScriptData* cached_data, uint32_t expected_source_hash, SanityCheckResult* rejection_result) { DisallowHeapAllocation no_gc; SerializedCodeData scd(cached_data); *rejection_result = scd.SanityCheck(expected_source_hash); if (*rejection_result != CHECK_SUCCESS) { cached_data->Reject(); return SerializedCodeData(nullptr, 0); } return scd; } } // namespace internal } // namespace v8