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// 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 <memory> #include "src/base/logging.h" #include "src/base/platform/elapsed-timer.h" #include "src/base/platform/platform.h" #include "src/baseline/baseline-batch-compiler.h" #include "src/codegen/background-merge-task.h" #include "src/common/globals.h" #include "src/handles/maybe-handles.h" #include "src/handles/persistent-handles.h" #include "src/heap/heap-inl.h" #include "src/heap/parked-scope.h" #include "src/logging/counters-scopes.h" #include "src/logging/log.h" #include "src/logging/runtime-call-stats-scope.h" #include "src/objects/objects-inl.h" #include "src/objects/shared-function-info.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 { AlignedCachedData::AlignedCachedData(const uint8_t* data, int length) : owns_data_(false), rejected_(false), data_(data), length_(length) { if (!IsAligned(reinterpret_cast<intptr_t>(data), kPointerAlignment)) { uint8_t* copy = NewArray<uint8_t>(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) {} // static ScriptCompiler::CachedData* CodeSerializer::Serialize( Isolate* isolate, Handle<SharedFunctionInfo> info) { TRACE_EVENT_CALL_STATS_SCOPED(isolate, "v8", "V8.Execute"); NestedTimedHistogramScope histogram_timer( isolate->counters()->compile_serialize()); RCS_SCOPE(isolate, RuntimeCallCounterId::kCompileSerialize); TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.CompileSerialize"); base::ElapsedTimer timer; if (v8_flags.profile_deserialization) timer.Start(); Handle<Script> script(Script::cast(info->script()), isolate); if (v8_flags.trace_serializer) { PrintF("[Serializing from"); ShortPrint(script->name()); PrintF("]\n"); } #if V8_ENABLE_WEBASSEMBLY // TODO(7110): Enable serialization of Asm modules once the AsmWasmData is // context independent. if (script->ContainsAsmModule()) return nullptr; #endif // V8_ENABLE_WEBASSEMBLY // Serialize code object. Handle<String> source(String::cast(script->source()), isolate); HandleScope scope(isolate); CodeSerializer cs(isolate, SerializedCodeData::SourceHash( source, script->origin_options())); DisallowGarbageCollection no_gc; cs.reference_map()->AddAttachedReference(*source); AlignedCachedData* cached_data = cs.SerializeSharedFunctionInfo(info); if (v8_flags.profile_deserialization) { double ms = timer.Elapsed().InMillisecondsF(); int length = cached_data->length(); PrintF("[Serializing to %d bytes took %0.3f ms]\n", length, ms); } ScriptCompiler::CachedData* result = new ScriptCompiler::CachedData(cached_data->data(), cached_data->length(), ScriptCompiler::CachedData::BufferOwned); cached_data->ReleaseDataOwnership(); delete cached_data; return result; } AlignedCachedData* CodeSerializer::SerializeSharedFunctionInfo( Handle<SharedFunctionInfo> info) { DisallowGarbageCollection no_gc; VisitRootPointer(Root::kHandleScope, nullptr, FullObjectSlot(info.location())); SerializeDeferredObjects(); Pad(); SerializedCodeData data(sink_.data(), this); return data.GetScriptData(); } void CodeSerializer::SerializeObjectImpl(Handle<HeapObject> obj, SlotType slot_type) { ReadOnlyRoots roots(isolate()); InstanceType instance_type; { DisallowGarbageCollection no_gc; Tagged<HeapObject> raw = *obj; if (SerializeHotObject(raw)) return; if (SerializeRoot(raw)) return; if (SerializeBackReference(raw)) return; if (SerializeReadOnlyObjectReference(raw, &sink_)) return; instance_type = raw->map()->instance_type(); CHECK(!InstanceTypeChecker::IsInstructionStream(instance_type)); } if (InstanceTypeChecker::IsScript(instance_type)) { Handle<FixedArray> host_options; Handle<Object> context_data; { DisallowGarbageCollection no_gc; Tagged<Script> script_obj = Script::cast(*obj); DCHECK_NE(script_obj->compilation_type(), Script::CompilationType::kEval); // 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()) Tagged<Object> raw_context_data = script_obj->context_data(); if (raw_context_data != roots.undefined_value() && raw_context_data != roots.uninitialized_symbol()) { script_obj->set_context_data(roots.undefined_value()); } context_data = handle(raw_context_data, isolate()); // We don't want to serialize host options to avoid serializing // unnecessary object graph. host_options = handle(script_obj->host_defined_options(), isolate()); script_obj->set_host_defined_options(roots.empty_fixed_array()); } SerializeGeneric(obj, slot_type); { DisallowGarbageCollection no_gc; Tagged<Script> script_obj = Script::cast(*obj); script_obj->set_host_defined_options(*host_options); script_obj->set_context_data(*context_data); } return; } else if (InstanceTypeChecker::IsSharedFunctionInfo(instance_type)) { Handle<DebugInfo> debug_info; bool restore_bytecode = false; { DisallowGarbageCollection no_gc; Tagged<SharedFunctionInfo> sfi = SharedFunctionInfo::cast(*obj); DCHECK(!sfi->IsApiFunction()); #if V8_ENABLE_WEBASSEMBLY // TODO(7110): Enable serializing of Asm modules once the AsmWasmData // is context independent. DCHECK(!sfi->HasAsmWasmData()); #endif // V8_ENABLE_WEBASSEMBLY if (auto maybe_debug_info = sfi->TryGetDebugInfo(isolate())) { debug_info = handle(maybe_debug_info.value(), isolate()); // Clear debug info. if (debug_info->HasInstrumentedBytecodeArray()) { restore_bytecode = true; sfi->SetActiveBytecodeArray(debug_info->OriginalBytecodeArray()); } } } SerializeGeneric(obj, slot_type); if (restore_bytecode) { DisallowGarbageCollection no_gc; Tagged<SharedFunctionInfo> sfi = SharedFunctionInfo::cast(*obj); sfi->SetActiveBytecodeArray(debug_info->DebugBytecodeArray()); } return; } else if (InstanceTypeChecker::IsUncompiledDataWithoutPreparseDataWithJob( instance_type)) { Handle<UncompiledDataWithoutPreparseDataWithJob> data = Handle<UncompiledDataWithoutPreparseDataWithJob>::cast(obj); Address job = data->job(); data->set_job(kNullAddress); SerializeGeneric(data, slot_type); data->set_job(job); return; } else if (InstanceTypeChecker::IsUncompiledDataWithPreparseDataAndJob( instance_type)) { Handle<UncompiledDataWithPreparseDataAndJob> data = Handle<UncompiledDataWithPreparseDataAndJob>::cast(obj); Address job = data->job(); data->set_job(kNullAddress); SerializeGeneric(data, slot_type); data->set_job(job); 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 if (V8_UNLIKELY(v8_flags.interpreted_frames_native_stack) && IsInterpreterData(*obj)) { obj = handle(InterpreterData::cast(*obj)->bytecode_array(), isolate()); } // Past this point we should not see any (context-specific) maps anymore. CHECK(!InstanceTypeChecker::IsMap(instance_type)); // There should be no references to the global object embedded. CHECK(!InstanceTypeChecker::IsJSGlobalProxy(instance_type) && !InstanceTypeChecker::IsJSGlobalObject(instance_type)); // Embedded FixedArrays that need rehashing must support rehashing. CHECK_IMPLIES(obj->NeedsRehashing(cage_base()), obj->CanBeRehashed(cage_base())); // We expect no instantiated function objects or contexts. CHECK(!InstanceTypeChecker::IsJSFunction(instance_type) && !InstanceTypeChecker::IsContext(instance_type)); SerializeGeneric(obj, slot_type); } void CodeSerializer::SerializeGeneric(Handle<HeapObject> heap_object, SlotType slot_type) { // Object has not yet been serialized. Serialize it here. ObjectSerializer serializer(this, heap_object, &sink_); serializer.Serialize(slot_type); } namespace { // NOTE(mmarchini): when v8_flags.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> result_sfi, bool log_code_creation) { DCHECK_IMPLIES(isolate->NeedsSourcePositions(), log_code_creation); Handle<Script> script(Script::cast(result_sfi->script()), isolate); if (log_code_creation) Script::InitLineEnds(isolate, script); Tagged<String> name = ReadOnlyRoots(isolate).empty_string(); if (IsString(script->name())) name = String::cast(script->name()); Handle<String> name_handle(name, isolate); SharedFunctionInfo::ScriptIterator iter(isolate, *script); for (Tagged<SharedFunctionInfo> shared_info = iter.Next(); !shared_info.is_null(); shared_info = iter.Next()) { IsCompiledScope is_compiled(shared_info, isolate); if (!is_compiled.is_compiled()) continue; DCHECK(shared_info->HasBytecodeArray()); Handle<SharedFunctionInfo> sfi = handle(shared_info, isolate); Handle<Code> code = Builtins::CreateInterpreterEntryTrampolineForProfiling(isolate); Handle<InterpreterData> interpreter_data = Handle<InterpreterData>::cast(isolate->factory()->NewStruct( INTERPRETER_DATA_TYPE, AllocationType::kOld)); interpreter_data->set_bytecode_array(sfi->GetBytecodeArray(isolate)); interpreter_data->set_interpreter_trampoline(*code); if (sfi->HasBaselineCode()) { sfi->baseline_code(kAcquireLoad) ->set_bytecode_or_interpreter_data(*interpreter_data); } else { sfi->set_interpreter_data(*interpreter_data); } if (!log_code_creation) continue; SharedFunctionInfo::EnsureSourcePositionsAvailable(isolate, sfi); Handle<AbstractCode> abstract_code = Handle<AbstractCode>::cast(code); Script::PositionInfo info; Script::GetPositionInfo(script, sfi->StartPosition(), &info); int line_num = info.line_start + 1; int column_num = info.line_end + 1; PROFILE(isolate, CodeCreateEvent(LogEventListener::CodeTag::kFunction, abstract_code, sfi, name_handle, line_num, column_num)); } } class StressOffThreadDeserializeThread final : public base::Thread { public: explicit StressOffThreadDeserializeThread(Isolate* isolate, AlignedCachedData* cached_data) : Thread( base::Thread::Options("StressOffThreadDeserializeThread", 2 * MB)), isolate_(isolate), cached_data_(cached_data) {} void Run() final { LocalIsolate local_isolate(isolate_, ThreadKind::kBackground); UnparkedScope unparked_scope(&local_isolate); LocalHandleScope handle_scope(&local_isolate); off_thread_data_ = CodeSerializer::StartDeserializeOffThread(&local_isolate, cached_data_); } MaybeHandle<SharedFunctionInfo> Finalize(Isolate* isolate, Handle<String> source, ScriptOriginOptions origin_options) { return CodeSerializer::FinishOffThreadDeserialize( isolate, std::move(off_thread_data_), cached_data_, source, origin_options); } private: Isolate* isolate_; AlignedCachedData* cached_data_; CodeSerializer::OffThreadDeserializeData off_thread_data_; }; void FinalizeDeserialization(Isolate* isolate, Handle<SharedFunctionInfo> result, const base::ElapsedTimer& timer) { // Devtools can report time in this function as profiler overhead, since none // of the following tasks would need to happen normally. TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.FinalizeDeserialization"); const bool log_code_creation = isolate->IsLoggingCodeCreation(); if (V8_UNLIKELY(v8_flags.interpreted_frames_native_stack)) { CreateInterpreterDataForDeserializedCode(isolate, result, log_code_creation); } bool needs_source_positions = isolate->NeedsSourcePositions(); if (!log_code_creation && !needs_source_positions) return; Handle<Script> script(Script::cast(result->script()), isolate); if (needs_source_positions) { Script::InitLineEnds(isolate, script); } Handle<String> name(IsString(script->name()) ? Tagged<String>::cast(script->name()) : ReadOnlyRoots(isolate).empty_string(), isolate); if (V8_UNLIKELY(v8_flags.log_function_events)) { LOG(isolate, FunctionEvent("deserialize", script->id(), timer.Elapsed().InMillisecondsF(), result->StartPosition(), result->EndPosition(), *name)); } SharedFunctionInfo::ScriptIterator iter(isolate, *script); for (Tagged<SharedFunctionInfo> info = iter.Next(); !info.is_null(); info = iter.Next()) { if (!info->is_compiled()) continue; Handle<SharedFunctionInfo> shared_info(info, isolate); if (needs_source_positions) { SharedFunctionInfo::EnsureSourcePositionsAvailable(isolate, shared_info); } Script::PositionInfo pos_info; Script::GetPositionInfo(script, shared_info->StartPosition(), &pos_info); int line_num = pos_info.line + 1; int column_num = pos_info.column + 1; PROFILE(isolate, CodeCreateEvent( shared_info->is_toplevel() ? LogEventListener::CodeTag::kScript : LogEventListener::CodeTag::kFunction, handle(shared_info->abstract_code(isolate), isolate), shared_info, name, line_num, column_num)); } } void BaselineBatchCompileIfSparkplugCompiled(Isolate* isolate, Tagged<Script> script) { // Here is main thread, we trigger early baseline compilation only in // concurrent sparkplug and baseline batch compilation mode which consumes // little main thread execution time. if (v8_flags.concurrent_sparkplug && v8_flags.baseline_batch_compilation) { SharedFunctionInfo::ScriptIterator iter(isolate, script); for (Tagged<SharedFunctionInfo> info = iter.Next(); !info.is_null(); info = iter.Next()) { if (info->sparkplug_compiled() && CanCompileWithBaseline(isolate, info)) { isolate->baseline_batch_compiler()->EnqueueSFI(info); } } } } const char* ToString(SerializedCodeSanityCheckResult result) { switch (result) { case SerializedCodeSanityCheckResult::kSuccess: return "success"; case SerializedCodeSanityCheckResult::kMagicNumberMismatch: return "magic number mismatch"; case SerializedCodeSanityCheckResult::kVersionMismatch: return "version mismatch"; case SerializedCodeSanityCheckResult::kSourceMismatch: return "source mismatch"; case SerializedCodeSanityCheckResult::kFlagsMismatch: return "flags mismatch"; case SerializedCodeSanityCheckResult::kChecksumMismatch: return "checksum mismatch"; case SerializedCodeSanityCheckResult::kInvalidHeader: return "invalid header"; case SerializedCodeSanityCheckResult::kLengthMismatch: return "length mismatch"; case SerializedCodeSanityCheckResult::kReadOnlySnapshotChecksumMismatch: return "read-only snapshot checksum mismatch"; } } } // namespace MaybeHandle<SharedFunctionInfo> CodeSerializer::Deserialize( Isolate* isolate, AlignedCachedData* cached_data, Handle<String> source, ScriptOriginOptions origin_options, MaybeHandle<Script> maybe_cached_script) { if (v8_flags.stress_background_compile) { StressOffThreadDeserializeThread thread(isolate, cached_data); CHECK(thread.Start()); thread.Join(); return thread.Finalize(isolate, source, origin_options); // TODO(leszeks): Compare off-thread deserialized data to on-thread. } base::ElapsedTimer timer; if (v8_flags.profile_deserialization || v8_flags.log_function_events) { timer.Start(); } HandleScope scope(isolate); SerializedCodeSanityCheckResult sanity_check_result = SerializedCodeSanityCheckResult::kSuccess; const SerializedCodeData scd = SerializedCodeData::FromCachedData( isolate, cached_data, SerializedCodeData::SourceHash(source, origin_options), &sanity_check_result); if (sanity_check_result != SerializedCodeSanityCheckResult::kSuccess) { if (v8_flags.profile_deserialization) { PrintF("[Cached code failed check: %s]\n", ToString(sanity_check_result)); } DCHECK(cached_data->rejected()); isolate->counters()->code_cache_reject_reason()->AddSample( static_cast<int>(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 (v8_flags.profile_deserialization) PrintF("[Deserializing failed]\n"); return MaybeHandle<SharedFunctionInfo>(); } // Check whether the newly deserialized data should be merged into an // existing Script from the Isolate compilation cache. If so, perform // the merge in a single-threaded manner since this deserialization was // single-threaded. if (Handle<Script> cached_script; maybe_cached_script.ToHandle(&cached_script)) { BackgroundMergeTask merge; merge.SetUpOnMainThread(isolate, cached_script); CHECK(merge.HasPendingBackgroundWork()); Handle<Script> new_script = handle(Script::cast(result->script()), isolate); merge.BeginMergeInBackground(isolate->AsLocalIsolate(), new_script); CHECK(merge.HasPendingForegroundWork()); result = merge.CompleteMergeInForeground(isolate, new_script); } BaselineBatchCompileIfSparkplugCompiled(isolate, Script::cast(result->script())); if (v8_flags.profile_deserialization) { double ms = timer.Elapsed().InMillisecondsF(); int length = cached_data->length(); PrintF("[Deserializing from %d bytes took %0.3f ms]\n", length, ms); } FinalizeDeserialization(isolate, result, timer); return scope.CloseAndEscape(result); } Handle<Script> CodeSerializer::OffThreadDeserializeData::GetOnlyScript( LocalHeap* heap) { std::unique_ptr<PersistentHandles> previous_persistent_handles = heap->DetachPersistentHandles(); heap->AttachPersistentHandles(std::move(persistent_handles)); DCHECK_EQ(scripts.size(), 1); // Make a non-persistent handle to return. Handle<Script> script = handle(*scripts[0], heap); DCHECK_EQ(*script, maybe_result.ToHandleChecked()->script()); persistent_handles = heap->DetachPersistentHandles(); if (previous_persistent_handles) { heap->AttachPersistentHandles(std::move(previous_persistent_handles)); } return script; } CodeSerializer::OffThreadDeserializeData CodeSerializer::StartDeserializeOffThread(LocalIsolate* local_isolate, AlignedCachedData* cached_data) { OffThreadDeserializeData result; DCHECK(!local_isolate->heap()->HasPersistentHandles()); const SerializedCodeData scd = SerializedCodeData::FromCachedDataWithoutSource( local_isolate, cached_data, &result.sanity_check_result); if (result.sanity_check_result != SerializedCodeSanityCheckResult::kSuccess) { // Exit early but don't report yet, we'll re-check this when finishing on // the main thread DCHECK(cached_data->rejected()); return result; } MaybeHandle<SharedFunctionInfo> local_maybe_result = OffThreadObjectDeserializer::DeserializeSharedFunctionInfo( local_isolate, &scd, &result.scripts); result.maybe_result = local_isolate->heap()->NewPersistentMaybeHandle(local_maybe_result); result.persistent_handles = local_isolate->heap()->DetachPersistentHandles(); return result; } MaybeHandle<SharedFunctionInfo> CodeSerializer::FinishOffThreadDeserialize( Isolate* isolate, OffThreadDeserializeData&& data, AlignedCachedData* cached_data, Handle<String> source, ScriptOriginOptions origin_options, BackgroundMergeTask* background_merge_task) { base::ElapsedTimer timer; if (v8_flags.profile_deserialization || v8_flags.log_function_events) { timer.Start(); } HandleScope scope(isolate); // Do a source sanity check now that we have the source. It's important for // FromPartiallySanityCheckedCachedData call that the sanity_check_result // holds the result of the off-thread sanity check. SerializedCodeSanityCheckResult sanity_check_result = data.sanity_check_result; const SerializedCodeData scd = SerializedCodeData::FromPartiallySanityCheckedCachedData( cached_data, SerializedCodeData::SourceHash(source, origin_options), &sanity_check_result); if (sanity_check_result != SerializedCodeSanityCheckResult::kSuccess) { // The only case where the deserialization result could exist despite a // check failure is on a source mismatch, since we can't test for this // off-thread. DCHECK_IMPLIES(!data.maybe_result.is_null(), sanity_check_result == SerializedCodeSanityCheckResult::kSourceMismatch); // The only kind of sanity check we can't test for off-thread is a source // mismatch. DCHECK_IMPLIES(sanity_check_result != data.sanity_check_result, sanity_check_result == SerializedCodeSanityCheckResult::kSourceMismatch); if (v8_flags.profile_deserialization) { PrintF("[Cached code failed check: %s]\n", ToString(sanity_check_result)); } DCHECK(cached_data->rejected()); isolate->counters()->code_cache_reject_reason()->AddSample( static_cast<int>(sanity_check_result)); return MaybeHandle<SharedFunctionInfo>(); } Handle<SharedFunctionInfo> result; if (!data.maybe_result.ToHandle(&result)) { // Deserializing may fail if the reservations cannot be fulfilled. if (v8_flags.profile_deserialization) { PrintF("[Off-thread deserializing failed]\n"); } return MaybeHandle<SharedFunctionInfo>(); } // Change the result persistent handle into a regular handle. DCHECK(data.persistent_handles->Contains(result.location())); result = handle(*result, isolate); if (background_merge_task && background_merge_task->HasPendingForegroundWork()) { Handle<Script> script = handle(Script::cast(result->script()), isolate); result = background_merge_task->CompleteMergeInForeground(isolate, script); DCHECK(Object::StrictEquals(Script::cast(result->script())->source(), *source)); DCHECK(isolate->factory()->script_list()->Contains( MaybeObject::MakeWeak(MaybeObject::FromObject(result->script())))); } else { Handle<Script> script(Script::cast(result->script()), isolate); // Fix up the source on the script. This should be the only deserialized // script, and the off-thread deserializer should have set its source to // the empty string. DCHECK_EQ(data.scripts.size(), 1); DCHECK_EQ(*script, *data.scripts[0]); DCHECK_EQ(script->source(), ReadOnlyRoots(isolate).empty_string()); Script::SetSource(isolate, script, source); // Fix up the script list to include the newly deserialized script. Handle<WeakArrayList> list = isolate->factory()->script_list(); for (Handle<Script> script : data.scripts) { BaselineBatchCompileIfSparkplugCompiled(isolate, *script); DCHECK(data.persistent_handles->Contains(script.location())); list = WeakArrayList::AddToEnd(isolate, list, MaybeObjectHandle::Weak(script)); } isolate->heap()->SetRootScriptList(*list); } if (v8_flags.profile_deserialization) { double ms = timer.Elapsed().InMillisecondsF(); int length = cached_data->length(); PrintF("[Finishing off-thread deserialize from %d bytes took %0.3f ms]\n", length, ms); } FinalizeDeserialization(isolate, result, timer); DCHECK(!background_merge_task || !background_merge_task->HasPendingForegroundWork()); return scope.CloseAndEscape(result); } SerializedCodeData::SerializedCodeData(const std::vector<uint8_t>* payload, const CodeSerializer* cs) { DisallowGarbageCollection no_gc; // Calculate sizes. uint32_t size = kHeaderSize + 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, kHeaderSize); // Set header values. SetMagicNumber(); SetHeaderValue(kVersionHashOffset, Version::Hash()); SetHeaderValue(kSourceHashOffset, cs->source_hash()); SetHeaderValue(kFlagHashOffset, FlagList::Hash()); SetHeaderValue(kReadOnlySnapshotChecksumOffset, Snapshot::ExtractReadOnlySnapshotChecksum( cs->isolate()->snapshot_blob())); SetHeaderValue(kPayloadLengthOffset, static_cast<uint32_t>(payload->size())); // Zero out any padding in the header. memset(data_ + kUnalignedHeaderSize, 0, kHeaderSize - kUnalignedHeaderSize); // Copy serialized data. CopyBytes(data_ + kHeaderSize, payload->data(), static_cast<size_t>(payload->size())); uint32_t checksum = v8_flags.verify_snapshot_checksum ? Checksum(ChecksummedContent()) : 0; SetHeaderValue(kChecksumOffset, checksum); } SerializedCodeSanityCheckResult SerializedCodeData::SanityCheck( uint32_t expected_ro_snapshot_checksum, uint32_t expected_source_hash) const { SerializedCodeSanityCheckResult result = SanityCheckWithoutSource(expected_ro_snapshot_checksum); if (result != SerializedCodeSanityCheckResult::kSuccess) return result; return SanityCheckJustSource(expected_source_hash); } SerializedCodeSanityCheckResult SerializedCodeData::SanityCheckJustSource( uint32_t expected_source_hash) const { uint32_t source_hash = GetHeaderValue(kSourceHashOffset); if (source_hash != expected_source_hash) { return SerializedCodeSanityCheckResult::kSourceMismatch; } return SerializedCodeSanityCheckResult::kSuccess; } SerializedCodeSanityCheckResult SerializedCodeData::SanityCheckWithoutSource( uint32_t expected_ro_snapshot_checksum) const { if (size_ < kHeaderSize) { return SerializedCodeSanityCheckResult::kInvalidHeader; } uint32_t magic_number = GetMagicNumber(); if (magic_number != kMagicNumber) { return SerializedCodeSanityCheckResult::kMagicNumberMismatch; } uint32_t version_hash = GetHeaderValue(kVersionHashOffset); if (version_hash != Version::Hash()) { return SerializedCodeSanityCheckResult::kVersionMismatch; } uint32_t flags_hash = GetHeaderValue(kFlagHashOffset); if (flags_hash != FlagList::Hash()) { return SerializedCodeSanityCheckResult::kFlagsMismatch; } uint32_t ro_snapshot_checksum = GetHeaderValue(kReadOnlySnapshotChecksumOffset); if (ro_snapshot_checksum != expected_ro_snapshot_checksum) { return SerializedCodeSanityCheckResult::kReadOnlySnapshotChecksumMismatch; } uint32_t payload_length = GetHeaderValue(kPayloadLengthOffset); uint32_t max_payload_length = size_ - kHeaderSize; if (payload_length > max_payload_length) { return SerializedCodeSanityCheckResult::kLengthMismatch; } if (v8_flags.verify_snapshot_checksum) { uint32_t checksum = GetHeaderValue(kChecksumOffset); if (Checksum(ChecksummedContent()) != checksum) { return SerializedCodeSanityCheckResult::kChecksumMismatch; } } return SerializedCodeSanityCheckResult::kSuccess; } 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. AlignedCachedData* SerializedCodeData::GetScriptData() { DCHECK(owns_data_); AlignedCachedData* result = new AlignedCachedData(data_, size_); result->AcquireDataOwnership(); owns_data_ = false; data_ = nullptr; return result; } base::Vector<const uint8_t> SerializedCodeData::Payload() const { const uint8_t* payload = data_ + kHeaderSize; DCHECK(IsAligned(reinterpret_cast<intptr_t>(payload), kPointerAlignment)); int length = GetHeaderValue(kPayloadLengthOffset); DCHECK_EQ(data_ + size_, payload + length); return base::Vector<const uint8_t>(payload, length); } SerializedCodeData::SerializedCodeData(AlignedCachedData* data) : SerializedData(const_cast<uint8_t*>(data->data()), data->length()) {} SerializedCodeData SerializedCodeData::FromCachedData( Isolate* isolate, AlignedCachedData* cached_data, uint32_t expected_source_hash, SerializedCodeSanityCheckResult* rejection_result) { DisallowGarbageCollection no_gc; SerializedCodeData scd(cached_data); *rejection_result = scd.SanityCheck( Snapshot::ExtractReadOnlySnapshotChecksum(isolate->snapshot_blob()), expected_source_hash); if (*rejection_result != SerializedCodeSanityCheckResult::kSuccess) { cached_data->Reject(); return SerializedCodeData(nullptr, 0); } return scd; } SerializedCodeData SerializedCodeData::FromCachedDataWithoutSource( LocalIsolate* local_isolate, AlignedCachedData* cached_data, SerializedCodeSanityCheckResult* rejection_result) { DisallowGarbageCollection no_gc; SerializedCodeData scd(cached_data); *rejection_result = scd.SanityCheckWithoutSource(Snapshot::ExtractReadOnlySnapshotChecksum( local_isolate->snapshot_blob())); if (*rejection_result != SerializedCodeSanityCheckResult::kSuccess) { cached_data->Reject(); return SerializedCodeData(nullptr, 0); } return scd; } SerializedCodeData SerializedCodeData::FromPartiallySanityCheckedCachedData( AlignedCachedData* cached_data, uint32_t expected_source_hash, SerializedCodeSanityCheckResult* rejection_result) { DisallowGarbageCollection no_gc; // The previous call to FromCachedDataWithoutSource may have already rejected // the cached data, so re-use the previous rejection result if it's not a // success. if (*rejection_result != SerializedCodeSanityCheckResult::kSuccess) { // FromCachedDataWithoutSource doesn't check the source, so there can't be // a source mismatch. DCHECK_NE(*rejection_result, SerializedCodeSanityCheckResult::kSourceMismatch); cached_data->Reject(); return SerializedCodeData(nullptr, 0); } SerializedCodeData scd(cached_data); *rejection_result = scd.SanityCheckJustSource(expected_source_hash); if (*rejection_result != SerializedCodeSanityCheckResult::kSuccess) { // This check only checks the source, so the only possible failure is a // source mismatch. DCHECK_EQ(*rejection_result, SerializedCodeSanityCheckResult::kSourceMismatch); cached_data->Reject(); return SerializedCodeData(nullptr, 0); } return scd; } } // namespace internal } // namespace v8