// 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/counters.h" #include "src/debug/debug.h" #include "src/heap/heap-inl.h" #include "src/log.h" #include "src/macro-assembler.h" #include "src/objects-inl.h" #include "src/objects/slots.h" #include "src/snapshot/object-deserializer.h" #include "src/snapshot/snapshot.h" #include "src/version.h" #include "src/visitors.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), 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; isolate->heap()->read_only_space()->ClearStringPaddingIfNeeded(); // 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) { PagedSpace* read_only_space = isolate()->heap()->read_only_space(); if (!read_only_space->Contains(obj)) return false; // For objects in RO_SPACE, 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(); Page* page = Page::FromAddress(address); uint32_t chunk_index = 0; for (Page* p : *read_only_space) { if (p == page) break; ++chunk_index; } uint32_t chunk_offset = static_cast<uint32_t>(page->Offset(address)); SerializerReference back_reference = SerializerReference::BackReference(RO_SPACE, 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; } if (obj->IsBytecodeArray()) { // Clear the stack frame cache if present BytecodeArray::cast(obj)->ClearFrameCacheFromSourcePositionTable(); } // 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(); } 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( isolate, 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 = 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); } bool log_code_creation = isolate->logger()->is_listening_to_code_events() || isolate->is_profiling() || isolate->code_event_dispatcher()->IsListeningToCodeEvents(); if (log_code_creation || FLAG_log_function_events) { String name = ReadOnlyRoots(isolate).empty_string(); Script script = Script::cast(result->script()); Handle<Script> script_handle(script, isolate); if (script->name()->IsString()) name = String::cast(script->name()); 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(Handle<Script>(script, isolate)); DisallowHeapAllocation no_gc; SharedFunctionInfo::ScriptIterator iter(isolate, script); for (i::SharedFunctionInfo info = iter.Next(); !info.is_null(); info = iter.Next()) { if (info->is_compiled()) { int line_num = script->GetLineNumber(info->StartPosition()) + 1; int column_num = script->GetColumnNumber(info->StartPosition()) + 1; PROFILE(isolate, CodeCreateEvent(CodeEventListener::SCRIPT_TAG, info->abstract_code(), info, name, line_num, column_num)); } } } } if (isolate->NeedsSourcePositionsForProfiling()) { Handle<Script> script(Script::cast(result->script()), isolate); Script::InitLineEnds(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())); Checksum checksum(ChecksummedContent()); SetHeaderValue(kChecksumPartAOffset, checksum.a()); SetHeaderValue(kChecksumPartBOffset, checksum.b()); } SerializedCodeData::SanityCheckResult SerializedCodeData::SanityCheck( Isolate* isolate, 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 c1 = GetHeaderValue(kChecksumPartAOffset); uint32_t c2 = GetHeaderValue(kChecksumPartBOffset); 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()).Check(c1, c2)) 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( Isolate* isolate, ScriptData* cached_data, uint32_t expected_source_hash, SanityCheckResult* rejection_result) { DisallowHeapAllocation no_gc; SerializedCodeData scd(cached_data); *rejection_result = scd.SanityCheck(isolate, expected_source_hash); if (*rejection_result != CHECK_SUCCESS) { cached_data->Reject(); return SerializedCodeData(nullptr, 0); } return scd; } } // namespace internal } // namespace v8