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chromium / v8 / v8 / c991d8f3846e89b1cd745f0cabe4eaea54d75c0c / . / src / snapshot / serialize.cc
blob: 86da3cc48452a79ee9b7659fe89db997ebf395e8 [file] [log] [blame]
// Copyright 2012 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/serialize.h"
#include "src/accessors.h"
#include "src/api.h"
#include "src/base/platform/platform.h"
#include "src/bootstrapper.h"
#include "src/code-stubs.h"
#include "src/deoptimizer.h"
#include "src/execution.h"
#include "src/global-handles.h"
#include "src/ic/ic.h"
#include "src/ic/stub-cache.h"
#include "src/objects.h"
#include "src/parser.h"
#include "src/profiler/cpu-profiler.h"
#include "src/runtime/runtime.h"
#include "src/snapshot/natives.h"
#include "src/snapshot/snapshot.h"
#include "src/snapshot/snapshot-source-sink.h"
#include "src/v8.h"
#include "src/v8threads.h"
#include "src/version.h"
namespace v8 {
namespace internal {
// -----------------------------------------------------------------------------
// Coding of external references.
ExternalReferenceTable* ExternalReferenceTable::instance(Isolate* isolate) {
ExternalReferenceTable* external_reference_table =
isolate->external_reference_table();
if (external_reference_table == NULL) {
external_reference_table = new ExternalReferenceTable(isolate);
isolate->set_external_reference_table(external_reference_table);
}
return external_reference_table;
}
ExternalReferenceTable::ExternalReferenceTable(Isolate* isolate) {
// Miscellaneous
Add(ExternalReference::roots_array_start(isolate).address(),
"Heap::roots_array_start()");
Add(ExternalReference::address_of_stack_limit(isolate).address(),
"StackGuard::address_of_jslimit()");
Add(ExternalReference::address_of_real_stack_limit(isolate).address(),
"StackGuard::address_of_real_jslimit()");
Add(ExternalReference::new_space_start(isolate).address(),
"Heap::NewSpaceStart()");
Add(ExternalReference::new_space_mask(isolate).address(),
"Heap::NewSpaceMask()");
Add(ExternalReference::new_space_allocation_limit_address(isolate).address(),
"Heap::NewSpaceAllocationLimitAddress()");
Add(ExternalReference::new_space_allocation_top_address(isolate).address(),
"Heap::NewSpaceAllocationTopAddress()");
Add(ExternalReference::debug_step_in_fp_address(isolate).address(),
"Debug::step_in_fp_addr()");
Add(ExternalReference::mod_two_doubles_operation(isolate).address(),
"mod_two_doubles");
// Keyed lookup cache.
Add(ExternalReference::keyed_lookup_cache_keys(isolate).address(),
"KeyedLookupCache::keys()");
Add(ExternalReference::keyed_lookup_cache_field_offsets(isolate).address(),
"KeyedLookupCache::field_offsets()");
Add(ExternalReference::handle_scope_next_address(isolate).address(),
"HandleScope::next");
Add(ExternalReference::handle_scope_limit_address(isolate).address(),
"HandleScope::limit");
Add(ExternalReference::handle_scope_level_address(isolate).address(),
"HandleScope::level");
Add(ExternalReference::new_deoptimizer_function(isolate).address(),
"Deoptimizer::New()");
Add(ExternalReference::compute_output_frames_function(isolate).address(),
"Deoptimizer::ComputeOutputFrames()");
Add(ExternalReference::address_of_min_int().address(),
"LDoubleConstant::min_int");
Add(ExternalReference::address_of_one_half().address(),
"LDoubleConstant::one_half");
Add(ExternalReference::isolate_address(isolate).address(), "isolate");
Add(ExternalReference::address_of_negative_infinity().address(),
"LDoubleConstant::negative_infinity");
Add(ExternalReference::power_double_double_function(isolate).address(),
"power_double_double_function");
Add(ExternalReference::power_double_int_function(isolate).address(),
"power_double_int_function");
Add(ExternalReference::math_log_double_function(isolate).address(),
"std::log");
Add(ExternalReference::store_buffer_top(isolate).address(),
"store_buffer_top");
Add(ExternalReference::address_of_the_hole_nan().address(), "the_hole_nan");
Add(ExternalReference::get_date_field_function(isolate).address(),
"JSDate::GetField");
Add(ExternalReference::date_cache_stamp(isolate).address(),
"date_cache_stamp");
Add(ExternalReference::address_of_pending_message_obj(isolate).address(),
"address_of_pending_message_obj");
Add(ExternalReference::get_make_code_young_function(isolate).address(),
"Code::MakeCodeYoung");
Add(ExternalReference::cpu_features().address(), "cpu_features");
Add(ExternalReference::old_space_allocation_top_address(isolate).address(),
"Heap::OldSpaceAllocationTopAddress");
Add(ExternalReference::old_space_allocation_limit_address(isolate).address(),
"Heap::OldSpaceAllocationLimitAddress");
Add(ExternalReference::allocation_sites_list_address(isolate).address(),
"Heap::allocation_sites_list_address()");
Add(ExternalReference::address_of_uint32_bias().address(), "uint32_bias");
Add(ExternalReference::get_mark_code_as_executed_function(isolate).address(),
"Code::MarkCodeAsExecuted");
Add(ExternalReference::is_profiling_address(isolate).address(),
"CpuProfiler::is_profiling");
Add(ExternalReference::scheduled_exception_address(isolate).address(),
"Isolate::scheduled_exception");
Add(ExternalReference::invoke_function_callback(isolate).address(),
"InvokeFunctionCallback");
Add(ExternalReference::invoke_accessor_getter_callback(isolate).address(),
"InvokeAccessorGetterCallback");
Add(ExternalReference::log_enter_external_function(isolate).address(),
"Logger::EnterExternal");
Add(ExternalReference::log_leave_external_function(isolate).address(),
"Logger::LeaveExternal");
Add(ExternalReference::address_of_minus_one_half().address(),
"double_constants.minus_one_half");
Add(ExternalReference::stress_deopt_count(isolate).address(),
"Isolate::stress_deopt_count_address()");
Add(ExternalReference::vector_store_virtual_register(isolate).address(),
"Isolate::vector_store_virtual_register()");
Add(ExternalReference::runtime_function_table_address(isolate).address(),
"Runtime::runtime_function_table_address()");
// Debug addresses
Add(ExternalReference::debug_after_break_target_address(isolate).address(),
"Debug::after_break_target_address()");
Add(ExternalReference::debug_restarter_frame_function_pointer_address(isolate)
.address(),
"Debug::restarter_frame_function_pointer_address()");
Add(ExternalReference::debug_is_active_address(isolate).address(),
"Debug::is_active_address()");
#ifndef V8_INTERPRETED_REGEXP
Add(ExternalReference::re_case_insensitive_compare_uc16(isolate).address(),
"NativeRegExpMacroAssembler::CaseInsensitiveCompareUC16()");
Add(ExternalReference::re_check_stack_guard_state(isolate).address(),
"RegExpMacroAssembler*::CheckStackGuardState()");
Add(ExternalReference::re_grow_stack(isolate).address(),
"NativeRegExpMacroAssembler::GrowStack()");
Add(ExternalReference::re_word_character_map().address(),
"NativeRegExpMacroAssembler::word_character_map");
Add(ExternalReference::address_of_regexp_stack_limit(isolate).address(),
"RegExpStack::limit_address()");
Add(ExternalReference::address_of_regexp_stack_memory_address(isolate)
.address(),
"RegExpStack::memory_address()");
Add(ExternalReference::address_of_regexp_stack_memory_size(isolate).address(),
"RegExpStack::memory_size()");
Add(ExternalReference::address_of_static_offsets_vector(isolate).address(),
"OffsetsVector::static_offsets_vector");
#endif // V8_INTERPRETED_REGEXP
// The following populates all of the different type of external references
// into the ExternalReferenceTable.
//
// NOTE: This function was originally 100k of code. It has since been
// rewritten to be mostly table driven, as the callback macro style tends to
// very easily cause code bloat. Please be careful in the future when adding
// new references.
struct RefTableEntry {
uint16_t id;
const char* name;
};
static const RefTableEntry c_builtins[] = {
#define DEF_ENTRY_C(name, ignored) \
{ Builtins::c_##name, "Builtins::" #name } \
,
BUILTIN_LIST_C(DEF_ENTRY_C)
#undef DEF_ENTRY_C
};
for (unsigned i = 0; i < arraysize(c_builtins); ++i) {
ExternalReference ref(static_cast<Builtins::CFunctionId>(c_builtins[i].id),
isolate);
Add(ref.address(), c_builtins[i].name);
}
static const RefTableEntry builtins[] = {
#define DEF_ENTRY_C(name, ignored) \
{ Builtins::k##name, "Builtins::" #name } \
,
#define DEF_ENTRY_A(name, i1, i2, i3) \
{ Builtins::k##name, "Builtins::" #name } \
,
BUILTIN_LIST_C(DEF_ENTRY_C) BUILTIN_LIST_A(DEF_ENTRY_A)
BUILTIN_LIST_DEBUG_A(DEF_ENTRY_A)
#undef DEF_ENTRY_C
#undef DEF_ENTRY_A
};
for (unsigned i = 0; i < arraysize(builtins); ++i) {
ExternalReference ref(static_cast<Builtins::Name>(builtins[i].id), isolate);
Add(ref.address(), builtins[i].name);
}
static const RefTableEntry runtime_functions[] = {
#define RUNTIME_ENTRY(name, i1, i2) \
{ Runtime::k##name, "Runtime::" #name } \
,
FOR_EACH_INTRINSIC(RUNTIME_ENTRY)
#undef RUNTIME_ENTRY
};
for (unsigned i = 0; i < arraysize(runtime_functions); ++i) {
ExternalReference ref(
static_cast<Runtime::FunctionId>(runtime_functions[i].id), isolate);
Add(ref.address(), runtime_functions[i].name);
}
// Stat counters
struct StatsRefTableEntry {
StatsCounter* (Counters::*counter)();
const char* name;
};
static const StatsRefTableEntry stats_ref_table[] = {
#define COUNTER_ENTRY(name, caption) \
{ &Counters::name, "Counters::" #name } \
,
STATS_COUNTER_LIST_1(COUNTER_ENTRY) STATS_COUNTER_LIST_2(COUNTER_ENTRY)
#undef COUNTER_ENTRY
};
Counters* counters = isolate->counters();
for (unsigned i = 0; i < arraysize(stats_ref_table); ++i) {
// To make sure the indices are not dependent on whether counters are
// enabled, use a dummy address as filler.
Address address = NotAvailable();
StatsCounter* counter = (counters->*(stats_ref_table[i].counter))();
if (counter->Enabled()) {
address = reinterpret_cast<Address>(counter->GetInternalPointer());
}
Add(address, stats_ref_table[i].name);
}
// Top addresses
static const char* address_names[] = {
#define BUILD_NAME_LITERAL(Name, name) "Isolate::" #name "_address",
FOR_EACH_ISOLATE_ADDRESS_NAME(BUILD_NAME_LITERAL) NULL
#undef BUILD_NAME_LITERAL
};
for (int i = 0; i < Isolate::kIsolateAddressCount; ++i) {
Add(isolate->get_address_from_id(static_cast<Isolate::AddressId>(i)),
address_names[i]);
}
// Accessors
struct AccessorRefTable {
Address address;
const char* name;
};
static const AccessorRefTable accessors[] = {
#define ACCESSOR_INFO_DECLARATION(name) \
{ FUNCTION_ADDR(&Accessors::name##Getter), "Accessors::" #name "Getter" } \
, {FUNCTION_ADDR(&Accessors::name##Setter), "Accessors::" #name "Setter"},
ACCESSOR_INFO_LIST(ACCESSOR_INFO_DECLARATION)
#undef ACCESSOR_INFO_DECLARATION
};
for (unsigned i = 0; i < arraysize(accessors); ++i) {
Add(accessors[i].address, accessors[i].name);
}
StubCache* stub_cache = isolate->stub_cache();
// Stub cache tables
Add(stub_cache->key_reference(StubCache::kPrimary).address(),
"StubCache::primary_->key");
Add(stub_cache->value_reference(StubCache::kPrimary).address(),
"StubCache::primary_->value");
Add(stub_cache->map_reference(StubCache::kPrimary).address(),
"StubCache::primary_->map");
Add(stub_cache->key_reference(StubCache::kSecondary).address(),
"StubCache::secondary_->key");
Add(stub_cache->value_reference(StubCache::kSecondary).address(),
"StubCache::secondary_->value");
Add(stub_cache->map_reference(StubCache::kSecondary).address(),
"StubCache::secondary_->map");
// Runtime entries
Add(ExternalReference::delete_handle_scope_extensions(isolate).address(),
"HandleScope::DeleteExtensions");
Add(ExternalReference::incremental_marking_record_write_function(isolate)
.address(),
"IncrementalMarking::RecordWrite");
Add(ExternalReference::store_buffer_overflow_function(isolate).address(),
"StoreBuffer::StoreBufferOverflow");
// Add a small set of deopt entry addresses to encoder without generating the
// deopt table code, which isn't possible at deserialization time.
HandleScope scope(isolate);
for (int entry = 0; entry < kDeoptTableSerializeEntryCount; ++entry) {
Address address = Deoptimizer::GetDeoptimizationEntry(
isolate,
entry,
Deoptimizer::LAZY,
Deoptimizer::CALCULATE_ENTRY_ADDRESS);
Add(address, "lazy_deopt");
}
}
ExternalReferenceEncoder::ExternalReferenceEncoder(Isolate* isolate) {
map_ = isolate->external_reference_map();
if (map_ != NULL) return;
map_ = new HashMap(HashMap::PointersMatch);
ExternalReferenceTable* table = ExternalReferenceTable::instance(isolate);
for (int i = 0; i < table->size(); ++i) {
Address addr = table->address(i);
if (addr == ExternalReferenceTable::NotAvailable()) continue;
// We expect no duplicate external references entries in the table.
DCHECK_NULL(map_->Lookup(addr, Hash(addr)));
map_->LookupOrInsert(addr, Hash(addr))->value = reinterpret_cast<void*>(i);
}
isolate->set_external_reference_map(map_);
}
uint32_t ExternalReferenceEncoder::Encode(Address address) const {
DCHECK_NOT_NULL(address);
HashMap::Entry* entry =
const_cast<HashMap*>(map_)->Lookup(address, Hash(address));
DCHECK_NOT_NULL(entry);
return static_cast<uint32_t>(reinterpret_cast<intptr_t>(entry->value));
}
const char* ExternalReferenceEncoder::NameOfAddress(Isolate* isolate,
Address address) const {
HashMap::Entry* entry =
const_cast<HashMap*>(map_)->Lookup(address, Hash(address));
if (entry == NULL) return "<unknown>";
uint32_t i = static_cast<uint32_t>(reinterpret_cast<intptr_t>(entry->value));
return ExternalReferenceTable::instance(isolate)->name(i);
}
RootIndexMap::RootIndexMap(Isolate* isolate) {
map_ = isolate->root_index_map();
if (map_ != NULL) return;
map_ = new HashMap(HashMap::PointersMatch);
for (uint32_t i = 0; i < Heap::kStrongRootListLength; i++) {
Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(i);
Object* root = isolate->heap()->root(root_index);
// Omit root entries that can be written after initialization. They must
// not be referenced through the root list in the snapshot.
if (root->IsHeapObject() &&
isolate->heap()->RootCanBeTreatedAsConstant(root_index)) {
HeapObject* heap_object = HeapObject::cast(root);
HashMap::Entry* entry = LookupEntry(map_, heap_object, false);
if (entry != NULL) {
// Some are initialized to a previous value in the root list.
DCHECK_LT(GetValue(entry), i);
} else {
SetValue(LookupEntry(map_, heap_object, true), i);
}
}
}
isolate->set_root_index_map(map_);
}
class CodeAddressMap: public CodeEventLogger {
public:
explicit CodeAddressMap(Isolate* isolate)
: isolate_(isolate) {
isolate->logger()->addCodeEventListener(this);
}
virtual ~CodeAddressMap() {
isolate_->logger()->removeCodeEventListener(this);
}
virtual void CodeMoveEvent(Address from, Address to) {
address_to_name_map_.Move(from, to);
}
virtual void CodeDisableOptEvent(Code* code, SharedFunctionInfo* shared) {
}
virtual void CodeDeleteEvent(Address from) {
address_to_name_map_.Remove(from);
}
const char* Lookup(Address address) {
return address_to_name_map_.Lookup(address);
}
private:
class NameMap {
public:
NameMap() : impl_(HashMap::PointersMatch) {}
~NameMap() {
for (HashMap::Entry* p = impl_.Start(); p != NULL; p = impl_.Next(p)) {
DeleteArray(static_cast<const char*>(p->value));
}
}
void Insert(Address code_address, const char* name, int name_size) {
HashMap::Entry* entry = FindOrCreateEntry(code_address);
if (entry->value == NULL) {
entry->value = CopyName(name, name_size);
}
}
const char* Lookup(Address code_address) {
HashMap::Entry* entry = FindEntry(code_address);
return (entry != NULL) ? static_cast<const char*>(entry->value) : NULL;
}
void Remove(Address code_address) {
HashMap::Entry* entry = FindEntry(code_address);
if (entry != NULL) {
DeleteArray(static_cast<char*>(entry->value));
RemoveEntry(entry);
}
}
void Move(Address from, Address to) {
if (from == to) return;
HashMap::Entry* from_entry = FindEntry(from);
DCHECK(from_entry != NULL);
void* value = from_entry->value;
RemoveEntry(from_entry);
HashMap::Entry* to_entry = FindOrCreateEntry(to);
DCHECK(to_entry->value == NULL);
to_entry->value = value;
}
private:
static char* CopyName(const char* name, int name_size) {
char* result = NewArray<char>(name_size + 1);
for (int i = 0; i < name_size; ++i) {
char c = name[i];
if (c == '\0') c = ' ';
result[i] = c;
}
result[name_size] = '\0';
return result;
}
HashMap::Entry* FindOrCreateEntry(Address code_address) {
return impl_.LookupOrInsert(code_address,
ComputePointerHash(code_address));
}
HashMap::Entry* FindEntry(Address code_address) {
return impl_.Lookup(code_address, ComputePointerHash(code_address));
}
void RemoveEntry(HashMap::Entry* entry) {
impl_.Remove(entry->key, entry->hash);
}
HashMap impl_;
DISALLOW_COPY_AND_ASSIGN(NameMap);
};
virtual void LogRecordedBuffer(Code* code,
SharedFunctionInfo*,
const char* name,
int length) {
address_to_name_map_.Insert(code->address(), name, length);
}
NameMap address_to_name_map_;
Isolate* isolate_;
};
void Deserializer::DecodeReservation(
Vector<const SerializedData::Reservation> res) {
DCHECK_EQ(0, reservations_[NEW_SPACE].length());
STATIC_ASSERT(NEW_SPACE == 0);
int current_space = NEW_SPACE;
for (auto& r : res) {
reservations_[current_space].Add({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::FlushICacheForNewIsolate() {
DCHECK(!deserializing_user_code_);
// The entire isolate is newly deserialized. Simply flush all code pages.
PageIterator it(isolate_->heap()->code_space());
while (it.has_next()) {
Page* p = it.next();
Assembler::FlushICache(isolate_, p->area_start(),
p->area_end() - p->area_start());
}
}
void Deserializer::FlushICacheForNewCodeObjects() {
DCHECK(deserializing_user_code_);
for (Code* code : new_code_objects_) {
Assembler::FlushICache(isolate_, code->instruction_start(),
code->instruction_size());
}
}
bool Deserializer::ReserveSpace() {
#ifdef DEBUG
for (int i = NEW_SPACE; i < kNumberOfSpaces; ++i) {
CHECK(reservations_[i].length() > 0);
}
#endif // DEBUG
if (!isolate_->heap()->ReserveSpace(reservations_)) return false;
for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) {
high_water_[i] = reservations_[i][0].start;
}
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);
CHECK_EQ(magic_number_,
SerializedData::ComputeMagicNumber(external_reference_table_));
}
void Deserializer::Deserialize(Isolate* isolate) {
Initialize(isolate);
if (!ReserveSpace()) V8::FatalProcessOutOfMemory("deserializing context");
// No active threads.
DCHECK_NULL(isolate_->thread_manager()->FirstThreadStateInUse());
// No active handles.
DCHECK(isolate_->handle_scope_implementer()->blocks()->is_empty());
{
DisallowHeapAllocation no_gc;
isolate_->heap()->IterateSmiRoots(this);
isolate_->heap()->IterateStrongRoots(this, VISIT_ONLY_STRONG);
isolate_->heap()->RepairFreeListsAfterDeserialization();
isolate_->heap()->IterateWeakRoots(this, VISIT_ALL);
DeserializeDeferredObjects();
FlushICacheForNewIsolate();
}
isolate_->heap()->set_native_contexts_list(
isolate_->heap()->code_stub_context());
// The allocation site list is build during root iteration, but if no sites
// were encountered then it needs to be initialized to undefined.
if (isolate_->heap()->allocation_sites_list() == Smi::FromInt(0)) {
isolate_->heap()->set_allocation_sites_list(
isolate_->heap()->undefined_value());
}
// Update data pointers to the external strings containing natives sources.
Natives::UpdateSourceCache(isolate_->heap());
ExtraNatives::UpdateSourceCache(isolate_->heap());
CodeStubNatives::UpdateSourceCache(isolate_->heap());
// Issue code events for newly deserialized code objects.
LOG_CODE_EVENT(isolate_, LogCodeObjects());
LOG_CODE_EVENT(isolate_, LogCompiledFunctions());
}
MaybeHandle<Object> Deserializer::DeserializePartial(
Isolate* isolate, Handle<JSGlobalProxy> global_proxy,
Handle<FixedArray>* outdated_contexts_out) {
Initialize(isolate);
if (!ReserveSpace()) {
V8::FatalProcessOutOfMemory("deserialize context");
return MaybeHandle<Object>();
}
Vector<Handle<Object> > attached_objects = Vector<Handle<Object> >::New(1);
attached_objects[kGlobalProxyReference] = global_proxy;
SetAttachedObjects(attached_objects);
DisallowHeapAllocation no_gc;
// Keep track of the code space start and end pointers in case new
// code objects were unserialized
OldSpace* code_space = isolate_->heap()->code_space();
Address start_address = code_space->top();
Object* root;
Object* outdated_contexts;
VisitPointer(&root);
DeserializeDeferredObjects();
VisitPointer(&outdated_contexts);
// There's no code deserialized here. If this assert fires then that's
// changed and logging should be added to notify the profiler et al of the
// new code, which also has to be flushed from instruction cache.
CHECK_EQ(start_address, code_space->top());
CHECK(outdated_contexts->IsFixedArray());
*outdated_contexts_out =
Handle<FixedArray>(FixedArray::cast(outdated_contexts), isolate);
return Handle<Object>(root, isolate);
}
MaybeHandle<SharedFunctionInfo> Deserializer::DeserializeCode(
Isolate* isolate) {
Initialize(isolate);
if (!ReserveSpace()) {
return Handle<SharedFunctionInfo>();
} else {
deserializing_user_code_ = true;
HandleScope scope(isolate);
Handle<SharedFunctionInfo> result;
{
DisallowHeapAllocation no_gc;
Object* root;
VisitPointer(&root);
DeserializeDeferredObjects();
FlushICacheForNewCodeObjects();
result = Handle<SharedFunctionInfo>(SharedFunctionInfo::cast(root));
}
CommitPostProcessedObjects(isolate);
return scope.CloseAndEscape(result);
}
}
Deserializer::~Deserializer() {
// TODO(svenpanne) Re-enable this assertion when v8 initialization is fixed.
// DCHECK(source_.AtEOF());
attached_objects_.Dispose();
}
// 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::VisitPointers(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::DeserializeDeferredObjects() {
for (int code = source_.Get(); code != kSynchronize; code = source_.Get()) {
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);
}
}
// Used to insert a deserialized internalized string into the string table.
class StringTableInsertionKey : public HashTableKey {
public:
explicit StringTableInsertionKey(String* string)
: string_(string), hash_(HashForObject(string)) {
DCHECK(string->IsInternalizedString());
}
bool IsMatch(Object* string) override {
// We know that all entries in a hash table had their hash keys created.
// Use that knowledge to have fast failure.
if (hash_ != HashForObject(string)) return false;
// We want to compare the content of two internalized strings here.
return string_->SlowEquals(String::cast(string));
}
uint32_t Hash() override { return hash_; }
uint32_t HashForObject(Object* key) override {
return String::cast(key)->Hash();
}
MUST_USE_RESULT virtual Handle<Object> AsHandle(Isolate* isolate) override {
return handle(string_, isolate);
}
private:
String* string_;
uint32_t hash_;
DisallowHeapAllocation no_gc;
};
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_.Add(handle(string));
return string;
} else {
string->SetForwardedInternalizedString(canonical);
return canonical;
}
}
} else if (obj->IsScript()) {
new_scripts_.Add(handle(Script::cast(obj)));
} else {
DCHECK(CanBeDeferred(obj));
}
}
if (obj->IsAllocationSite()) {
DCHECK(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::FromInt(0)) {
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_.Add(Code::cast(obj));
}
}
// Check alignment.
DCHECK_EQ(0, Heap::GetFillToAlign(obj->address(), obj->RequiredAlignment()));
return obj;
}
void Deserializer::CommitPostProcessedObjects(Isolate* isolate) {
StringTable::EnsureCapacityForDeserialization(
isolate, new_internalized_strings_.length());
for (Handle<String> string : new_internalized_strings_) {
StringTableInsertionKey key(*string);
DCHECK_NULL(StringTable::LookupKeyIfExists(isolate, &key));
StringTable::LookupKey(isolate, &key);
}
Heap* heap = isolate->heap();
Factory* factory = isolate->factory();
for (Handle<Script> script : new_scripts_) {
// Assign a new script id to avoid collision.
script->set_id(isolate_->heap()->NextScriptId());
// Add script to list.
Handle<Object> list = WeakFixedArray::Add(factory->script_list(), script);
heap->SetRootScriptList(*list);
}
}
HeapObject* Deserializer::GetBackReferencedObject(int space) {
HeapObject* obj;
BackReference back_reference(source_.GetInt());
if (space == LO_SPACE) {
CHECK(back_reference.chunk_index() == 0);
uint32_t index = back_reference.large_object_index();
obj = deserialized_large_objects_[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 (FLAG_log_snapshot_positions) {
LOG(isolate_, SnapshotPositionEvent(address, source_.position()));
}
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 = HeapObject::cast(result.ToObjectChecked());
deserialized_large_objects_.Add(obj);
return obj->address();
} 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];
CHECK_LE(high_water_[space_index], reservation[chunk_index].end);
#endif
return address;
}
}
Object** Deserializer::CopyInNativesSource(Vector<const char> source_vector,
Object** current) {
DCHECK(!isolate_->heap()->deserialization_complete());
NativesExternalStringResource* resource = new NativesExternalStringResource(
source_vector.start(), source_vector.length());
Object* resource_obj = reinterpret_cast<Object*>(resource);
UnalignedCopy(current++, &resource_obj);
return current;
}
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) \
{ \
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); \
} 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); \
int reference_id = source_.GetInt(); \
Address address = external_reference_table_->address(reference_id); \
new_object = reinterpret_cast<Object*>(address); \
} else if (where == kAttachedReference) { \
int index = source_.GetInt(); \
DCHECK(deserializing_user_code() || index == kGlobalProxyReference); \
new_object = *attached_objects_[index]; \
emit_write_barrier = isolate->heap()->InNewSpace(new_object); \
} else { \
DCHECK(where == kBuiltin); \
DCHECK(deserializing_user_code()); \
int builtin_id = source_.GetInt(); \
DCHECK_LE(0, builtin_id); \
DCHECK_LT(builtin_id, Builtins::builtin_count); \
Builtins::Name name = static_cast<Builtins::Name>(builtin_id); \
new_object = isolate->builtins()->builtin(name); \
emit_write_barrier = false; \
} \
if (within == kInnerPointer) { \
if (space_number != CODE_SPACE || new_object->IsCode()) { \
Code* new_code_object = reinterpret_cast<Code*>(new_object); \
new_object = \
reinterpret_cast<Object*>(new_code_object->instruction_start()); \
} else { \
DCHECK(space_number == CODE_SPACE); \
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( \
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); \
isolate->heap()->RecordWrite( \
current_object_address, \
static_cast<int>(current_address - current_object_address)); \
} \
if (!current_was_incremented) { \
current++; \
} \
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)
// Support for direct instruction pointers in functions. It's an inner
// pointer because it points at the entry point, not at the start of the
// code object.
SINGLE_CASE(kNewObject, kPlain, kInnerPointer, CODE_SPACE)
// 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 defined(V8_TARGET_ARCH_MIPS) || defined(V8_TARGET_ARCH_MIPS64) || \
defined(V8_TARGET_ARCH_PPC) || V8_EMBEDDED_CONSTANT_POOL
// Deserialize a new object from pointer found in code and write
// a pointer to it to the current object. Required only for MIPS, PPC or
// ARM 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 or ARM 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)
ALL_SPACES(kBackref, kPlain, kInnerPointer)
ALL_SPACES(kBackrefWithSkip, kPlain, 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 defined(V8_TARGET_ARCH_MIPS) || defined(V8_TARGET_ARCH_MIPS64) || \
defined(V8_TARGET_ARCH_PPC) || V8_EMBEDDED_CONSTANT_POOL
// 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)
// Find an code entry in the partial snapshots cache and
// write a pointer to it to the current object.
SINGLE_CASE(kPartialSnapshotCache, kPlain, 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, kPlain, kInnerPointer, 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, kPlain, kInnerPointer, 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(
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.length());
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;
case kNativesStringResource:
current = CopyInNativesSource(Natives::GetScriptSource(source_.Get()),
current);
break;
case kExtraNativesStringResource:
current = CopyInNativesSource(
ExtraNatives::GetScriptSource(source_.Get()), current);
break;
case kCodeStubNativesStringResource:
current = CopyInNativesSource(
CodeStubNatives::GetScriptSource(source_.Get()), current);
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);
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 kAlignmentPrefix:
case kAlignmentPrefix + 1:
case kAlignmentPrefix + 2: {
DCHECK_EQ(kWordAligned, next_alignment_);
next_alignment_ =
static_cast<AllocationAlignment>(data - (kAlignmentPrefix - 1));
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(
current_object_address,
static_cast<int>(current_address - current_object_address));
}
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;
}
Serializer::Serializer(Isolate* isolate, SnapshotByteSink* sink)
: isolate_(isolate),
sink_(sink),
external_reference_encoder_(isolate),
root_index_map_(isolate),
recursion_depth_(0),
code_address_map_(NULL),
large_objects_total_size_(0),
seen_large_objects_index_(0) {
// The serializer is meant to be used only to generate initial heap images
// from a context in which there is only one isolate.
for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) {
pending_chunk_[i] = 0;
max_chunk_size_[i] = static_cast<uint32_t>(
MemoryAllocator::PageAreaSize(static_cast<AllocationSpace>(i)));
}
#ifdef OBJECT_PRINT
if (FLAG_serialization_statistics) {
instance_type_count_ = NewArray<int>(kInstanceTypes);
instance_type_size_ = NewArray<size_t>(kInstanceTypes);
for (int i = 0; i < kInstanceTypes; i++) {
instance_type_count_[i] = 0;
instance_type_size_[i] = 0;
}
} else {
instance_type_count_ = NULL;
instance_type_size_ = NULL;
}
#endif // OBJECT_PRINT
}
Serializer::~Serializer() {
if (code_address_map_ != NULL) delete code_address_map_;
#ifdef OBJECT_PRINT
if (instance_type_count_ != NULL) {
DeleteArray(instance_type_count_);
DeleteArray(instance_type_size_);
}
#endif // OBJECT_PRINT
}
#ifdef OBJECT_PRINT
void Serializer::CountInstanceType(Map* map, int size) {
int instance_type = map->instance_type();
instance_type_count_[instance_type]++;
instance_type_size_[instance_type] += size;
}
#endif // OBJECT_PRINT
void Serializer::OutputStatistics(const char* name) {
if (!FLAG_serialization_statistics) return;
PrintF("%s:\n", name);
PrintF(" Spaces (bytes):\n");
for (int space = 0; space < kNumberOfSpaces; space++) {
PrintF("%16s", AllocationSpaceName(static_cast<AllocationSpace>(space)));
}
PrintF("\n");
for (int space = 0; space < kNumberOfPreallocatedSpaces; space++) {
size_t s = pending_chunk_[space];
for (uint32_t chunk_size : completed_chunks_[space]) s += chunk_size;
PrintF("%16" V8_PTR_PREFIX "d", s);
}
PrintF("%16d\n", large_objects_total_size_);
#ifdef OBJECT_PRINT
PrintF(" Instance types (count and bytes):\n");
#define PRINT_INSTANCE_TYPE(Name) \
if (instance_type_count_[Name]) { \
PrintF("%10d %10" V8_PTR_PREFIX "d %s\n", instance_type_count_[Name], \
instance_type_size_[Name], #Name); \
}
INSTANCE_TYPE_LIST(PRINT_INSTANCE_TYPE)
#undef PRINT_INSTANCE_TYPE
PrintF("\n");
#endif // OBJECT_PRINT
}
class Serializer::ObjectSerializer : public ObjectVisitor {
public:
ObjectSerializer(Serializer* serializer, Object* o, SnapshotByteSink* sink,
HowToCode how_to_code, WhereToPoint where_to_point)
: serializer_(serializer),
object_(HeapObject::cast(o)),
sink_(sink),
reference_representation_(how_to_code + where_to_point),
bytes_processed_so_far_(0),
is_code_object_(o->IsCode()),
code_has_been_output_(false) {}
void Serialize();
void SerializeDeferred();
void VisitPointers(Object** start, Object** end);
void VisitEmbeddedPointer(RelocInfo* target);
void VisitExternalReference(Address* p);
void VisitExternalReference(RelocInfo* rinfo);
void VisitInternalReference(RelocInfo* rinfo);
void VisitCodeTarget(RelocInfo* target);
void VisitCodeEntry(Address entry_address);
void VisitCell(RelocInfo* rinfo);
void VisitRuntimeEntry(RelocInfo* reloc);
// Used for seralizing the external strings that hold the natives source.
void VisitExternalOneByteString(
v8::String::ExternalOneByteStringResource** resource);
// We can't serialize a heap with external two byte strings.
void VisitExternalTwoByteString(
v8::String::ExternalStringResource** resource) {
UNREACHABLE();
}
private:
void SerializePrologue(AllocationSpace space, int size, Map* map);
bool SerializeExternalNativeSourceString(
int builtin_count,
v8::String::ExternalOneByteStringResource** resource_pointer,
FixedArray* source_cache, int resource_index);
enum ReturnSkip { kCanReturnSkipInsteadOfSkipping, kIgnoringReturn };
// This function outputs or skips the raw data between the last pointer and
// up to the current position. It optionally can just return the number of
// bytes to skip instead of performing a skip instruction, in case the skip
// can be merged into the next instruction.
int OutputRawData(Address up_to, ReturnSkip return_skip = kIgnoringReturn);
// External strings are serialized in a way to resemble sequential strings.
void SerializeExternalString();
Address PrepareCode();
Serializer* serializer_;
HeapObject* object_;
SnapshotByteSink* sink_;
int reference_representation_;
int bytes_processed_so_far_;
bool is_code_object_;
bool code_has_been_output_;
};
void Serializer::SerializeDeferredObjects() {
while (deferred_objects_.length() > 0) {
HeapObject* obj = deferred_objects_.RemoveLast();
ObjectSerializer obj_serializer(this, obj, sink_, kPlain, kStartOfObject);
obj_serializer.SerializeDeferred();
}
sink_->Put(kSynchronize, "Finished with deferred objects");
}
void StartupSerializer::SerializeStrongReferences() {
Isolate* isolate = this->isolate();
// No active threads.
CHECK_NULL(isolate->thread_manager()->FirstThreadStateInUse());
// No active or weak handles.
CHECK(isolate->handle_scope_implementer()->blocks()->is_empty());
CHECK_EQ(0, isolate->global_handles()->NumberOfWeakHandles());
CHECK_EQ(0, isolate->eternal_handles()->NumberOfHandles());
// We don't support serializing installed extensions.
CHECK(!isolate->has_installed_extensions());
isolate->heap()->IterateSmiRoots(this);
isolate->heap()->IterateStrongRoots(this, VISIT_ONLY_STRONG);
}
void StartupSerializer::VisitPointers(Object** start, Object** end) {
for (Object** current = start; current < end; current++) {
if (start == isolate()->heap()->roots_array_start()) {
root_index_wave_front_ =
Max(root_index_wave_front_, static_cast<intptr_t>(current - start));
}
if (ShouldBeSkipped(current)) {
sink_->Put(kSkip, "Skip");
sink_->PutInt(kPointerSize, "SkipOneWord");
} else if ((*current)->IsSmi()) {
sink_->Put(kOnePointerRawData, "Smi");
for (int i = 0; i < kPointerSize; i++) {
sink_->Put(reinterpret_cast<byte*>(current)[i], "Byte");
}
} else {
SerializeObject(HeapObject::cast(*current), kPlain, kStartOfObject, 0);
}
}
}
void PartialSerializer::Serialize(Object** o) {
if ((*o)->IsContext()) {
Context* context = Context::cast(*o);
global_object_ = context->global_object();
back_reference_map()->AddGlobalProxy(context->global_proxy());
// The bootstrap snapshot has a code-stub context. When serializing the
// partial snapshot, it is chained into the weak context list on the isolate
// and it's next context pointer may point to the code-stub context. Clear
// it before serializing, it will get re-added to the context list
// explicitly when it's loaded.
if (context->IsNativeContext()) {
context->set(Context::NEXT_CONTEXT_LINK,
isolate_->heap()->undefined_value());
DCHECK(!context->global_object()->IsUndefined());
DCHECK(!context->builtins()->IsUndefined());
}
}
VisitPointer(o);
SerializeDeferredObjects();
SerializeOutdatedContextsAsFixedArray();
Pad();
}
void PartialSerializer::SerializeOutdatedContextsAsFixedArray() {
int length = outdated_contexts_.length();
if (length == 0) {
FixedArray* empty = isolate_->heap()->empty_fixed_array();
SerializeObject(empty, kPlain, kStartOfObject, 0);
} else {
// Serialize an imaginary fixed array containing outdated contexts.
int size = FixedArray::SizeFor(length);
Allocate(NEW_SPACE, size);
sink_->Put(kNewObject + NEW_SPACE, "emulated FixedArray");
sink_->PutInt(size >> kObjectAlignmentBits, "FixedArray size in words");
Map* map = isolate_->heap()->fixed_array_map();
SerializeObject(map, kPlain, kStartOfObject, 0);
Smi* length_smi = Smi::FromInt(length);
sink_->Put(kOnePointerRawData, "Smi");
for (int i = 0; i < kPointerSize; i++) {
sink_->Put(reinterpret_cast<byte*>(&length_smi)[i], "Byte");
}
for (int i = 0; i < length; i++) {
Context* context = outdated_contexts_[i];
BackReference back_reference = back_reference_map_.Lookup(context);
sink_->Put(kBackref + back_reference.space(), "BackRef");
PutBackReference(context, back_reference);
}
}
}
bool Serializer::ShouldBeSkipped(Object** current) {
Object** roots = isolate()->heap()->roots_array_start();
return current == &roots[Heap::kStoreBufferTopRootIndex]
|| current == &roots[Heap::kStackLimitRootIndex]
|| current == &roots[Heap::kRealStackLimitRootIndex];
}
void Serializer::VisitPointers(Object** start, Object** end) {
for (Object** current = start; current < end; current++) {
if ((*current)->IsSmi()) {
sink_->Put(kOnePointerRawData, "Smi");
for (int i = 0; i < kPointerSize; i++) {
sink_->Put(reinterpret_cast<byte*>(current)[i], "Byte");
}
} else {
SerializeObject(HeapObject::cast(*current), kPlain, kStartOfObject, 0);
}
}
}
void Serializer::EncodeReservations(
List<SerializedData::Reservation>* out) const {
for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) {
for (int j = 0; j < completed_chunks_[i].length(); j++) {
out->Add(SerializedData::Reservation(completed_chunks_[i][j]));
}
if (pending_chunk_[i] > 0 || completed_chunks_[i].length() == 0) {
out->Add(SerializedData::Reservation(pending_chunk_[i]));
}
out->last().mark_as_last();
}
out->Add(SerializedData::Reservation(large_objects_total_size_));
out->last().mark_as_last();
}
// This ensures that the partial snapshot cache keeps things alive during GC and
// tracks their movement. When it is called during serialization of the startup
// snapshot nothing happens. When the partial (context) snapshot is created,
// this array is populated with the pointers that the partial snapshot will
// need. As that happens we emit serialized objects to the startup snapshot
// that correspond to the elements of this cache array. On deserialization we
// therefore need to visit the cache array. This fills it up with pointers to
// deserialized objects.
void SerializerDeserializer::Iterate(Isolate* isolate,
ObjectVisitor* visitor) {
if (isolate->serializer_enabled()) return;
List<Object*>* cache = isolate->partial_snapshot_cache();
for (int i = 0;; ++i) {
// Extend the array ready to get a value when deserializing.
if (cache->length() <= i) cache->Add(Smi::FromInt(0));
visitor->VisitPointer(&cache->at(i));
// Sentinel is the undefined object, which is a root so it will not normally
// be found in the cache.
if (cache->at(i)->IsUndefined()) break;
}
}
bool SerializerDeserializer::CanBeDeferred(HeapObject* o) {
return !o->IsString() && !o->IsScript();
}
int PartialSerializer::PartialSnapshotCacheIndex(HeapObject* heap_object) {
Isolate* isolate = this->isolate();
List<Object*>* cache = isolate->partial_snapshot_cache();
int new_index = cache->length();
int index = partial_cache_index_map_.LookupOrInsert(heap_object, new_index);
if (index == PartialCacheIndexMap::kInvalidIndex) {
// We didn't find the object in the cache. So we add it to the cache and
// then visit the pointer so that it becomes part of the startup snapshot
// and we can refer to it from the partial snapshot.
cache->Add(heap_object);
startup_serializer_->VisitPointer(reinterpret_cast<Object**>(&heap_object));
// We don't recurse from the startup snapshot generator into the partial
// snapshot generator.
return new_index;
}
return index;
}
bool PartialSerializer::ShouldBeInThePartialSnapshotCache(HeapObject* o) {
// Scripts should be referred only through shared function infos. We can't
// allow them to be part of the partial snapshot because they contain a
// unique ID, and deserializing several partial snapshots containing script
// would cause dupes.
DCHECK(!o->IsScript());
return o->IsName() || o->IsSharedFunctionInfo() || o->IsHeapNumber() ||
o->IsCode() || o->IsScopeInfo() || o->IsExecutableAccessorInfo() ||
o->map() ==
startup_serializer_->isolate()->heap()->fixed_cow_array_map();
}
#ifdef DEBUG
bool Serializer::BackReferenceIsAlreadyAllocated(BackReference reference) {
DCHECK(reference.is_valid());
DCHECK(!reference.is_source());
DCHECK(!reference.is_global_proxy());
AllocationSpace space = reference.space();
int chunk_index = reference.chunk_index();
if (space == LO_SPACE) {
return chunk_index == 0 &&
reference.large_object_index() < seen_large_objects_index_;
} else if (chunk_index == completed_chunks_[space].length()) {
return reference.chunk_offset() < pending_chunk_[space];
} else {
return chunk_index < completed_chunks_[space].length() &&
reference.chunk_offset() < completed_chunks_[space][chunk_index];
}
}
#endif // DEBUG
bool Serializer::SerializeKnownObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
if (how_to_code == kPlain && where_to_point == kStartOfObject) {
// Encode a reference to a hot object by its index in the working set.
int index = hot_objects_.Find(obj);
if (index != HotObjectsList::kNotFound) {
DCHECK(index >= 0 && index < kNumberOfHotObjects);
if (FLAG_trace_serializer) {
PrintF(" Encoding hot object %d:", index);
obj->ShortPrint();
PrintF("\n");
}
if (skip != 0) {
sink_->Put(kHotObjectWithSkip + index, "HotObjectWithSkip");
sink_->PutInt(skip, "HotObjectSkipDistance");
} else {
sink_->Put(kHotObject + index, "HotObject");
}
return true;
}
}
BackReference back_reference = back_reference_map_.Lookup(obj);
if (back_reference.is_valid()) {
// Encode the location of an already deserialized object in order to write
// its location into a later object. We can encode the location as an
// offset fromthe start of the deserialized objects or as an offset
// backwards from thecurrent allocation pointer.
if (back_reference.is_source()) {
FlushSkip(skip);
if (FLAG_trace_serializer) PrintF(" Encoding source object\n");
DCHECK(how_to_code == kPlain && where_to_point == kStartOfObject);
sink_->Put(kAttachedReference + kPlain + kStartOfObject, "Source");
sink_->PutInt(kSourceObjectReference, "kSourceObjectReference");
} else if (back_reference.is_global_proxy()) {
FlushSkip(skip);
if (FLAG_trace_serializer) PrintF(" Encoding global proxy\n");
DCHECK(how_to_code == kPlain && where_to_point == kStartOfObject);
sink_->Put(kAttachedReference + kPlain + kStartOfObject, "Global Proxy");
sink_->PutInt(kGlobalProxyReference, "kGlobalProxyReference");
} else {
if (FLAG_trace_serializer) {
PrintF(" Encoding back reference to: ");
obj->ShortPrint();
PrintF("\n");
}
PutAlignmentPrefix(obj);
AllocationSpace space = back_reference.space();
if (skip == 0) {
sink_->Put(kBackref + how_to_code + where_to_point + space, "BackRef");
} else {
sink_->Put(kBackrefWithSkip + how_to_code + where_to_point + space,
"BackRefWithSkip");
sink_->PutInt(skip, "BackRefSkipDistance");
}
PutBackReference(obj, back_reference);
}
return true;
}
return false;
}
StartupSerializer::StartupSerializer(Isolate* isolate, SnapshotByteSink* sink)
: Serializer(isolate, sink), root_index_wave_front_(0) {
// Clear the cache of objects used by the partial snapshot. After the
// strong roots have been serialized we can create a partial snapshot
// which will repopulate the cache with objects needed by that partial
// snapshot.
isolate->partial_snapshot_cache()->Clear();
InitializeCodeAddressMap();
}
void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
// Make sure that all functions are derived from the code-stub context
DCHECK(!obj->IsJSFunction() ||
JSFunction::cast(obj)->GetCreationContext() ==
isolate()->heap()->code_stub_context());
int root_index = root_index_map_.Lookup(obj);
// We can only encode roots as such if it has already been serialized.
// That applies to root indices below the wave front.
if (root_index != RootIndexMap::kInvalidRootIndex &&
root_index < root_index_wave_front_) {
PutRoot(root_index, obj, how_to_code, where_to_point, skip);
return;
}
if (obj->IsCode() && Code::cast(obj)->kind() == Code::FUNCTION) {
obj = isolate()->builtins()->builtin(Builtins::kCompileLazy);
}
if (SerializeKnownObject(obj, how_to_code, where_to_point, skip)) return;
FlushSkip(skip);
// Object has not yet been serialized. Serialize it here.
ObjectSerializer object_serializer(this, obj, sink_, how_to_code,
where_to_point);
object_serializer.Serialize();
}
void StartupSerializer::SerializeWeakReferencesAndDeferred() {
// This phase comes right after the serialization (of the snapshot).
// After we have done the partial serialization the partial snapshot cache
// will contain some references needed to decode the partial snapshot. We
// add one entry with 'undefined' which is the sentinel that the deserializer
// uses to know it is done deserializing the array.
Object* undefined = isolate()->heap()->undefined_value();
VisitPointer(&undefined);
isolate()->heap()->IterateWeakRoots(this, VISIT_ALL);
SerializeDeferredObjects();
Pad();
}
void Serializer::PutRoot(int root_index,
HeapObject* object,
SerializerDeserializer::HowToCode how_to_code,
SerializerDeserializer::WhereToPoint where_to_point,
int skip) {
if (FLAG_trace_serializer) {
PrintF(" Encoding root %d:", root_index);
object->ShortPrint();
PrintF("\n");
}
if (how_to_code == kPlain && where_to_point == kStartOfObject &&
root_index < kNumberOfRootArrayConstants &&
!isolate()->heap()->InNewSpace(object)) {
if (skip == 0) {
sink_->Put(kRootArrayConstants + root_index, "RootConstant");
} else {
sink_->Put(kRootArrayConstantsWithSkip + root_index, "RootConstant");
sink_->PutInt(skip, "SkipInPutRoot");
}
} else {
FlushSkip(skip);
sink_->Put(kRootArray + how_to_code + where_to_point, "RootSerialization");
sink_->PutInt(root_index, "root_index");
}
}
void Serializer::PutBackReference(HeapObject* object, BackReference reference) {
DCHECK(BackReferenceIsAlreadyAllocated(reference));
sink_->PutInt(reference.reference(), "BackRefValue");
hot_objects_.Add(object);
}
int Serializer::PutAlignmentPrefix(HeapObject* object) {
AllocationAlignment alignment = object->RequiredAlignment();
if (alignment != kWordAligned) {
DCHECK(1 <= alignment && alignment <= 3);
byte prefix = (kAlignmentPrefix - 1) + alignment;
sink_->Put(prefix, "Alignment");
return Heap::GetMaximumFillToAlign(alignment);
}
return 0;
}
void PartialSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
if (obj->IsMap()) {
// The code-caches link to context-specific code objects, which
// the startup and context serializes cannot currently handle.
DCHECK(Map::cast(obj)->code_cache() == obj->GetHeap()->empty_fixed_array());
}
// Replace typed arrays by undefined.
if (obj->IsJSTypedArray()) obj = isolate_->heap()->undefined_value();
int root_index = root_index_map_.Lookup(obj);
if (root_index != RootIndexMap::kInvalidRootIndex) {
PutRoot(root_index, obj, how_to_code, where_to_point, skip);
return;
}
if (ShouldBeInThePartialSnapshotCache(obj)) {
FlushSkip(skip);
int cache_index = PartialSnapshotCacheIndex(obj);
sink_->Put(kPartialSnapshotCache + how_to_code + where_to_point,
"PartialSnapshotCache");
sink_->PutInt(cache_index, "partial_snapshot_cache_index");
return;
}
// Pointers from the partial snapshot to the objects in the startup snapshot
// should go through the root array or through the partial snapshot cache.
// If this is not the case you may have to add something to the root array.
DCHECK(!startup_serializer_->back_reference_map()->Lookup(obj).is_valid());
// All the internalized strings that the partial snapshot needs should be
// either in the root table or in the partial snapshot cache.
DCHECK(!obj->IsInternalizedString());
if (SerializeKnownObject(obj, how_to_code, where_to_point, skip)) return;
FlushSkip(skip);
// Clear literal boilerplates.
if (obj->IsJSFunction() && !JSFunction::cast(obj)->shared()->bound()) {
FixedArray* literals = JSFunction::cast(obj)->literals();
for (int i = 0; i < literals->length(); i++) literals->set_undefined(i);
}
// Object has not yet been serialized. Serialize it here.
ObjectSerializer serializer(this, obj, sink_, how_to_code, where_to_point);
serializer.Serialize();
if (obj->IsContext() &&
Context::cast(obj)->global_object() == global_object_) {
// Context refers to the current global object. This reference will
// become outdated after deserialization.
outdated_contexts_.Add(Context::cast(obj));
}
}
void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space,
int size, Map* map) {
if (serializer_->code_address_map_) {
const char* code_name =
serializer_->code_address_map_->Lookup(object_->address());
LOG(serializer_->isolate_,
CodeNameEvent(object_->address(), sink_->Position(), code_name));
LOG(serializer_->isolate_,
SnapshotPositionEvent(object_->address(), sink_->Position()));
}
BackReference back_reference;
if (space == LO_SPACE) {
sink_->Put(kNewObject + reference_representation_ + space,
"NewLargeObject");
sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
if (object_->IsCode()) {
sink_->Put(EXECUTABLE, "executable large object");
} else {
sink_->Put(NOT_EXECUTABLE, "not executable large object");
}
back_reference = serializer_->AllocateLargeObject(size);
} else {
int fill = serializer_->PutAlignmentPrefix(object_);
back_reference = serializer_->Allocate(space, size + fill);
sink_->Put(kNewObject + reference_representation_ + space, "NewObject");
sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
}
#ifdef OBJECT_PRINT
if (FLAG_serialization_statistics) {
serializer_->CountInstanceType(map, size);
}
#endif // OBJECT_PRINT
// Mark this object as already serialized.
serializer_->back_reference_map()->Add(object_, back_reference);
// Serialize the map (first word of the object).
serializer_->SerializeObject(map, kPlain, kStartOfObject, 0);
}
void Serializer::ObjectSerializer::SerializeExternalString() {
// Instead of serializing this as an external string, we serialize
// an imaginary sequential string with the same content.
Isolate* isolate = serializer_->isolate();
DCHECK(object_->IsExternalString());
DCHECK(object_->map() != isolate->heap()->native_source_string_map());
ExternalString* string = ExternalString::cast(object_);
int length = string->length();
Map* map;
int content_size;
int allocation_size;
const byte* resource;
// Find the map and size for the imaginary sequential string.
bool internalized = object_->IsInternalizedString();
if (object_->IsExternalOneByteString()) {
map = internalized ? isolate->heap()->one_byte_internalized_string_map()
: isolate->heap()->one_byte_string_map();
allocation_size = SeqOneByteString::SizeFor(length);
content_size = length * kCharSize;
resource = reinterpret_cast<const byte*>(
ExternalOneByteString::cast(string)->resource()->data());
} else {
map = internalized ? isolate->heap()->internalized_string_map()
: isolate->heap()->string_map();
allocation_size = SeqTwoByteString::SizeFor(length);
content_size = length * kShortSize;
resource = reinterpret_cast<const byte*>(
ExternalTwoByteString::cast(string)->resource()->data());
}
AllocationSpace space = (allocation_size > Page::kMaxRegularHeapObjectSize)
? LO_SPACE
: OLD_SPACE;
SerializePrologue(space, allocation_size, map);
// Output the rest of the imaginary string.
int bytes_to_output = allocation_size - HeapObject::kHeaderSize;
// Output raw data header. Do not bother with common raw length cases here.
sink_->Put(kVariableRawData, "RawDataForString");
sink_->PutInt(bytes_to_output, "length");
// Serialize string header (except for map).
Address string_start = string->address();
for (int i = HeapObject::kHeaderSize; i < SeqString::kHeaderSize; i++) {
sink_->PutSection(string_start[i], "StringHeader");
}
// Serialize string content.
sink_->PutRaw(resource, content_size, "StringContent");
// Since the allocation size is rounded up to object alignment, there
// maybe left-over bytes that need to be padded.
int padding_size = allocation_size - SeqString::kHeaderSize - content_size;
DCHECK(0 <= padding_size && padding_size < kObjectAlignment);
for (int i = 0; i < padding_size; i++) sink_->PutSection(0, "StringPadding");
sink_->Put(kSkip, "SkipAfterString");
sink_->PutInt(bytes_to_output, "SkipDistance");
}
// Clear and later restore the next link in the weak cell, if the object is one.
class UnlinkWeakCellScope {
public:
explicit UnlinkWeakCellScope(HeapObject* object) : weak_cell_(NULL) {
if (object->IsWeakCell()) {
weak_cell_ = WeakCell::cast(object);
next_ = weak_cell_->next();
weak_cell_->clear_next(object->GetHeap());
}
}
~UnlinkWeakCellScope() {
if (weak_cell_) weak_cell_->set_next(next_, UPDATE_WEAK_WRITE_BARRIER);
}
private:
WeakCell* weak_cell_;
Object* next_;
DisallowHeapAllocation no_gc_;
};
void Serializer::ObjectSerializer::Serialize() {
if (FLAG_trace_serializer) {
PrintF(" Encoding heap object: ");
object_->ShortPrint();
PrintF("\n");
}
// We cannot serialize typed array objects correctly.
DCHECK(!object_->IsJSTypedArray());
// We don't expect fillers.
DCHECK(!object_->IsFiller());
if (object_->IsScript()) {
// Clear cached line ends.
Object* undefined = serializer_->isolate()->heap()->undefined_value();
Script::cast(object_)->set_line_ends(undefined);
}
if (object_->IsExternalString()) {
Heap* heap = serializer_->isolate()->heap();
if (object_->map() != heap->native_source_string_map()) {
// Usually we cannot recreate resources for external strings. To work
// around this, external strings are serialized to look like ordinary
// sequential strings.
// The exception are native source code strings, since we can recreate
// their resources. In that case we fall through and leave it to
// VisitExternalOneByteString further down.
SerializeExternalString();
return;
}
}
int size = object_->Size();
Map* map = object_->map();
AllocationSpace space =
MemoryChunk::FromAddress(object_->address())->owner()->identity();
SerializePrologue(space, size, map);
// Serialize the rest of the object.
CHECK_EQ(0, bytes_processed_so_far_);
bytes_processed_so_far_ = kPointerSize;
RecursionScope recursion(serializer_);
// Objects that are immediately post processed during deserialization
// cannot be deferred, since post processing requires the object content.
if (recursion.ExceedsMaximum() && CanBeDeferred(object_)) {
serializer_->QueueDeferredObject(object_);
sink_->Put(kDeferred, "Deferring object content");
return;
}
UnlinkWeakCellScope unlink_weak_cell(object_);
object_->IterateBody(map->instance_type(), size, this);
OutputRawData(object_->address() + size);
}
void Serializer::ObjectSerializer::SerializeDeferred() {
if (FLAG_trace_serializer) {
PrintF(" Encoding deferred heap object: ");
object_->ShortPrint();
PrintF("\n");
}
int size = object_->Size();
Map* map = object_->map();
BackReference reference = serializer_->back_reference_map()->Lookup(object_);
// Serialize the rest of the object.
CHECK_EQ(0, bytes_processed_so_far_);
bytes_processed_so_far_ = kPointerSize;
sink_->Put(kNewObject + reference.space(), "deferred object");
serializer_->PutBackReference(object_, reference);
sink_->PutInt(size >> kPointerSizeLog2, "deferred object size");
UnlinkWeakCellScope unlink_weak_cell(object_);
object_->IterateBody(map->instance_type(), size, this);
OutputRawData(object_->address() + size);
}
void Serializer::ObjectSerializer::VisitPointers(Object** start,
Object** end) {
Object** current = start;
while (current < end) {
while (current < end && (*current)->IsSmi()) current++;
if (current < end) OutputRawData(reinterpret_cast<Address>(current));
while (current < end && !(*current)->IsSmi()) {
HeapObject* current_contents = HeapObject::cast(*current);
int root_index = serializer_->root_index_map()->Lookup(current_contents);
// Repeats are not subject to the write barrier so we can only use
// immortal immovable root members. They are never in new space.
if (current != start && root_index != RootIndexMap::kInvalidRootIndex &&
Heap::RootIsImmortalImmovable(root_index) &&
current_contents == current[-1]) {
DCHECK(!serializer_->isolate()->heap()->InNewSpace(current_contents));
int repeat_count = 1;
while (&current[repeat_count] < end - 1 &&
current[repeat_count] == current_contents) {
repeat_count++;
}
current += repeat_count;
bytes_processed_so_far_ += repeat_count * kPointerSize;
if (repeat_count > kNumberOfFixedRepeat) {
sink_->Put(kVariableRepeat, "VariableRepeat");
sink_->PutInt(repeat_count, "repeat count");
} else {
sink_->Put(kFixedRepeatStart + repeat_count, "FixedRepeat");
}
} else {
serializer_->SerializeObject(
current_contents, kPlain, kStartOfObject, 0);
bytes_processed_so_far_ += kPointerSize;
current++;
}
}
}
}
void Serializer::ObjectSerializer::VisitEmbeddedPointer(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
Object* object = rinfo->target_object();
serializer_->SerializeObject(HeapObject::cast(object), how_to_code,
kStartOfObject, skip);
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitExternalReference(Address* p) {
int skip = OutputRawData(reinterpret_cast<Address>(p),
kCanReturnSkipInsteadOfSkipping);
sink_->Put(kExternalReference + kPlain + kStartOfObject, "ExternalRef");
sink_->PutInt(skip, "SkipB4ExternalRef");
Address target = *p;
sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
bytes_processed_so_far_ += kPointerSize;
}
void Serializer::ObjectSerializer::VisitExternalReference(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
sink_->PutInt(skip, "SkipB4ExternalRef");
Address target = rinfo->target_external_reference();
sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitInternalReference(RelocInfo* rinfo) {
// We can only reference to internal references of code that has been output.
DCHECK(is_code_object_ && code_has_been_output_);
// We do not use skip from last patched pc to find the pc to patch, since
// target_address_address may not return addresses in ascending order when
// used for internal references. External references may be stored at the
// end of the code in the constant pool, whereas internal references are
// inline. That would cause the skip to be negative. Instead, we store the
// offset from code entry.
Address entry = Code::cast(object_)->entry();
intptr_t pc_offset = rinfo->target_internal_reference_address() - entry;
intptr_t target_offset = rinfo->target_internal_reference() - entry;
DCHECK(0 <= pc_offset &&
pc_offset <= Code::cast(object_)->instruction_size());
DCHECK(0 <= target_offset &&
target_offset <= Code::cast(object_)->instruction_size());
sink_->Put(rinfo->rmode() == RelocInfo::INTERNAL_REFERENCE
? kInternalReference
: kInternalReferenceEncoded,
"InternalRef");
sink_->PutInt(static_cast<uintptr_t>(pc_offset), "internal ref address");
sink_->PutInt(static_cast<uintptr_t>(target_offset), "internal ref value");
}
void Serializer::ObjectSerializer::VisitRuntimeEntry(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
sink_->PutInt(skip, "SkipB4ExternalRef");
Address target = rinfo->target_address();
sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitCodeTarget(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
Code* object = Code::GetCodeFromTargetAddress(rinfo->target_address());
serializer_->SerializeObject(object, kFromCode, kInnerPointer, skip);
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitCodeEntry(Address entry_address) {
int skip = OutputRawData(entry_address, kCanReturnSkipInsteadOfSkipping);
Code* object = Code::cast(Code::GetObjectFromEntryAddress(entry_address));
serializer_->SerializeObject(object, kPlain, kInnerPointer, skip);
bytes_processed_so_far_ += kPointerSize;
}
void Serializer::ObjectSerializer::VisitCell(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->pc(), kCanReturnSkipInsteadOfSkipping);
Cell* object = Cell::cast(rinfo->target_cell());
serializer_->SerializeObject(object, kPlain, kInnerPointer, skip);
bytes_processed_so_far_ += kPointerSize;
}
bool Serializer::ObjectSerializer::SerializeExternalNativeSourceString(
int builtin_count,
v8::String::ExternalOneByteStringResource** resource_pointer,
FixedArray* source_cache, int resource_index) {
for (int i = 0; i < builtin_count; i++) {
Object* source = source_cache->get(i);
if (!source->IsUndefined()) {
ExternalOneByteString* string = ExternalOneByteString::cast(source);
typedef v8::String::ExternalOneByteStringResource Resource;
const Resource* resource = string->resource();
if (resource == *resource_pointer) {
sink_->Put(resource_index, "NativesStringResource");
sink_->PutSection(i, "NativesStringResourceEnd");
bytes_processed_so_far_ += sizeof(resource);
return true;
}
}
}
return false;
}
void Serializer::ObjectSerializer::VisitExternalOneByteString(
v8::String::ExternalOneByteStringResource** resource_pointer) {
Address references_start = reinterpret_cast<Address>(resource_pointer);
OutputRawData(references_start);
if (SerializeExternalNativeSourceString(
Natives::GetBuiltinsCount(), resource_pointer,
Natives::GetSourceCache(serializer_->isolate()->heap()),
kNativesStringResource)) {
return;
}
if (SerializeExternalNativeSourceString(
ExtraNatives::GetBuiltinsCount(), resource_pointer,
ExtraNatives::GetSourceCache(serializer_->isolate()->heap()),
kExtraNativesStringResource)) {
return;
}
if (SerializeExternalNativeSourceString(
CodeStubNatives::GetBuiltinsCount(), resource_pointer,
CodeStubNatives::GetSourceCache(serializer_->isolate()->heap()),
kCodeStubNativesStringResource)) {
return;
}
// One of the strings in the natives cache should match the resource. We
// don't expect any other kinds of external strings here.
UNREACHABLE();
}
Address Serializer::ObjectSerializer::PrepareCode() {
// To make snapshots reproducible, we make a copy of the code object
// and wipe all pointers in the copy, which we then serialize.
Code* original = Code::cast(object_);
Code* code = serializer_->CopyCode(original);
// Code age headers are not serializable.
code->MakeYoung(serializer_->isolate());
int mode_mask = RelocInfo::kCodeTargetMask |
RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY) |
RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED);
for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
RelocInfo* rinfo = it.rinfo();
rinfo->WipeOut();
}
// We need to wipe out the header fields *after* wiping out the
// relocations, because some of these fields are needed for the latter.
code->WipeOutHeader();
return code->address();
}
int Serializer::ObjectSerializer::OutputRawData(
Address up_to, Serializer::ObjectSerializer::ReturnSkip return_skip) {
Address object_start = object_->address();
int base = bytes_processed_so_far_;
int up_to_offset = static_cast<int>(up_to - object_start);
int to_skip = up_to_offset - bytes_processed_so_far_;
int bytes_to_output = to_skip;
bytes_processed_so_far_ += to_skip;
// This assert will fail if the reloc info gives us the target_address_address
// locations in a non-ascending order. Luckily that doesn't happen.
DCHECK(to_skip >= 0);
bool outputting_code = false;
if (to_skip != 0 && is_code_object_ && !code_has_been_output_) {
// Output the code all at once and fix later.
bytes_to_output = object_->Size() + to_skip - bytes_processed_so_far_;
outputting_code = true;
code_has_been_output_ = true;
}
if (bytes_to_output != 0 && (!is_code_object_ || outputting_code)) {
if (!outputting_code && bytes_to_output == to_skip &&
IsAligned(bytes_to_output, kPointerAlignment) &&
bytes_to_output <= kNumberOfFixedRawData * kPointerSize) {
int size_in_words = bytes_to_output >> kPointerSizeLog2;
sink_->PutSection(kFixedRawDataStart + size_in_words, "FixedRawData");
to_skip = 0; // This instruction includes skip.
} else {
// We always end up here if we are outputting the code of a code object.
sink_->Put(kVariableRawData, "VariableRawData");
sink_->PutInt(bytes_to_output, "length");
}
if (is_code_object_) object_start = PrepareCode();
const char* description = is_code_object_ ? "Code" : "Byte";
sink_->PutRaw(object_start + base, bytes_to_output, description);
}
if (to_skip != 0 && return_skip == kIgnoringReturn) {
sink_->Put(kSkip, "Skip");
sink_->PutInt(to_skip, "SkipDistance");
to_skip = 0;
}
return to_skip;
}
BackReference Serializer::AllocateLargeObject(int size) {
// Large objects are allocated one-by-one when deserializing. We do not
// have to keep track of multiple chunks.
large_objects_total_size_ += size;
return BackReference::LargeObjectReference(seen_large_objects_index_++);
}
BackReference Serializer::Allocate(AllocationSpace space, int size) {
DCHECK(space >= 0 && space < kNumberOfPreallocatedSpaces);
DCHECK(size > 0 && size <= static_cast<int>(max_chunk_size(space)));
uint32_t new_chunk_size = pending_chunk_[space] + size;
if (new_chunk_size > max_chunk_size(space)) {
// The new chunk size would not fit onto a single page. Complete the
// current chunk and start a new one.
sink_->Put(kNextChunk, "NextChunk");
sink_->Put(space, "NextChunkSpace");
completed_chunks_[space].Add(pending_chunk_[space]);
DCHECK_LE(completed_chunks_[space].length(), BackReference::kMaxChunkIndex);
pending_chunk_[space] = 0;
new_chunk_size = size;
}
uint32_t offset = pending_chunk_[space];
pending_chunk_[space] = new_chunk_size;
return BackReference::Reference(space, completed_chunks_[space].length(),
offset);
}
void Serializer::Pad() {
// The non-branching GetInt will read up to 3 bytes too far, so we need
// to pad the snapshot to make sure we don't read over the end.
for (unsigned i = 0; i < sizeof(int32_t) - 1; i++) {
sink_->Put(kNop, "Padding");
}
// Pad up to pointer size for checksum.
while (!IsAligned(sink_->Position(), kPointerAlignment)) {
sink_->Put(kNop, "Padding");
}
}
void Serializer::InitializeCodeAddressMap() {
isolate_->InitializeLoggingAndCounters();
code_address_map_ = new CodeAddressMap(isolate_);
}
Code* Serializer::CopyCode(Code* code) {
code_buffer_.Rewind(0); // Clear buffer without deleting backing store.
int size = code->CodeSize();
code_buffer_.AddAll(Vector<byte>(code->address(), size));
return Code::cast(HeapObject::FromAddress(&code_buffer_.first()));
}
ScriptData* CodeSerializer::Serialize(Isolate* isolate,
Handle<SharedFunctionInfo> info,
Handle<String> source) {
base::ElapsedTimer timer;
if (FLAG_profile_deserialization) timer.Start();
if (FLAG_trace_serializer) {
PrintF("[Serializing from");
Object* script = info->script();
if (script->IsScript()) Script::cast(script)->name()->ShortPrint();
PrintF("]\n");
}
// Serialize code object.
SnapshotByteSink sink(info->code()->CodeSize() * 2);
CodeSerializer cs(isolate, &sink, *source, info->code());
DisallowHeapAllocation no_gc;
Object** location = Handle<Object>::cast(info).location();
cs.VisitPointer(location);
cs.SerializeDeferredObjects();
cs.Pad();
SerializedCodeData data(sink.data(), cs);
ScriptData* script_data = data.GetScriptData();
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);
}
return script_data;
}
void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
int root_index = root_index_map_.Lookup(obj);
if (root_index != RootIndexMap::kInvalidRootIndex) {
PutRoot(root_index, obj, how_to_code, where_to_point, skip);
return;
}
if (SerializeKnownObject(obj, how_to_code, where_to_point, skip)) return;
FlushSkip(skip);
if (obj->IsCode()) {
Code* code_object = Code::cast(obj);
switch (code_object->kind()) {
case Code::OPTIMIZED_FUNCTION: // No optimized code compiled yet.
case Code::HANDLER: // No handlers patched in yet.
case Code::REGEXP: // No regexp literals initialized yet.
case Code::NUMBER_OF_KINDS: // Pseudo enum value.
CHECK(false);
case Code::BUILTIN:
SerializeBuiltin(code_object->builtin_index(), how_to_code,
where_to_point);
return;
case Code::STUB:
SerializeCodeStub(code_object->stub_key(), how_to_code, where_to_point);
return;
#define IC_KIND_CASE(KIND) case Code::KIND:
IC_KIND_LIST(IC_KIND_CASE)
#undef IC_KIND_CASE
SerializeIC(code_object, how_to_code, where_to_point);
return;
case Code::FUNCTION:
DCHECK(code_object->has_reloc_info_for_serialization());
// Only serialize the code for the toplevel function unless specified
// by flag. Replace code of inner functions by the lazy compile builtin.
// This is safe, as checked in Compiler::GetSharedFunctionInfo.
if (code_object != main_code_ && !FLAG_serialize_inner) {
SerializeBuiltin(Builtins::kCompileLazy, how_to_code, where_to_point);
} else {
SerializeGeneric(code_object, how_to_code, where_to_point);
}
return;
case Code::WASM_FUNCTION:
UNREACHABLE();
}
UNREACHABLE();
}
// 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->IsGlobalObject());
// There should be no hash table embedded. They would require rehashing.
CHECK(!obj->IsHashTable());
// We expect no instantiated function objects or contexts.
CHECK(!obj->IsJSFunction() && !obj->IsContext());
SerializeGeneric(obj, how_to_code, where_to_point);
}
void CodeSerializer::SerializeGeneric(HeapObject* heap_object,
HowToCode how_to_code,
WhereToPoint where_to_point) {
// Object has not yet been serialized. Serialize it here.
ObjectSerializer serializer(this, heap_object, sink_, how_to_code,
where_to_point);
serializer.Serialize();
}
void CodeSerializer::SerializeBuiltin(int builtin_index, HowToCode how_to_code,
WhereToPoint where_to_point) {
DCHECK((how_to_code == kPlain && where_to_point == kStartOfObject) ||
(how_to_code == kPlain && where_to_point == kInnerPointer) ||
(how_to_code == kFromCode && where_to_point == kInnerPointer));
DCHECK_LT(builtin_index, Builtins::builtin_count);
DCHECK_LE(0, builtin_index);
if (FLAG_trace_serializer) {
PrintF(" Encoding builtin: %s\n",
isolate()->builtins()->name(builtin_index));
}
sink_->Put(kBuiltin + how_to_code + where_to_point, "Builtin");
sink_->PutInt(builtin_index, "builtin_index");
}
void CodeSerializer::SerializeCodeStub(uint32_t stub_key, HowToCode how_to_code,
WhereToPoint where_to_point) {
DCHECK((how_to_code == kPlain && where_to_point == kStartOfObject) ||
(how_to_code == kPlain && where_to_point == kInnerPointer) ||
(how_to_code == kFromCode && where_to_point == kInnerPointer));
DCHECK(CodeStub::MajorKeyFromKey(stub_key) != CodeStub::NoCache);
DCHECK(!CodeStub::GetCode(isolate(), stub_key).is_null());
int index = AddCodeStubKey(stub_key) + kCodeStubsBaseIndex;
if (FLAG_trace_serializer) {
PrintF(" Encoding code stub %s as %d\n",
CodeStub::MajorName(CodeStub::MajorKeyFromKey(stub_key)), index);
}
sink_->Put(kAttachedReference + how_to_code + where_to_point, "CodeStub");
sink_->PutInt(index, "CodeStub key");
}
void CodeSerializer::SerializeIC(Code* ic, HowToCode how_to_code,
WhereToPoint where_to_point) {
// The IC may be implemented as a stub.
uint32_t stub_key = ic->stub_key();
if (stub_key != CodeStub::NoCacheKey()) {
if (FLAG_trace_serializer) {
PrintF(" %s is a code stub\n", Code::Kind2String(ic->kind()));
}
SerializeCodeStub(stub_key, how_to_code, where_to_point);
return;
}
// The IC may be implemented as builtin. Only real builtins have an
// actual builtin_index value attached (otherwise it's just garbage).
// Compare to make sure we are really dealing with a builtin.
int builtin_index = ic->builtin_index();
if (builtin_index < Builtins::builtin_count) {
Builtins::Name name = static_cast<Builtins::Name>(builtin_index);
Code* builtin = isolate()->builtins()->builtin(name);
if (builtin == ic) {
if (FLAG_trace_serializer) {
PrintF(" %s is a builtin\n", Code::Kind2String(ic->kind()));
}
DCHECK(ic->kind() == Code::KEYED_LOAD_IC ||
ic->kind() == Code::KEYED_STORE_IC);
SerializeBuiltin(builtin_index, how_to_code, where_to_point);
return;
}
}
// The IC may also just be a piece of code kept in the non_monomorphic_cache.
// In that case, just serialize as a normal code object.
if (FLAG_trace_serializer) {
PrintF(" %s has no special handling\n", Code::Kind2String(ic->kind()));
}
DCHECK(ic->kind() == Code::LOAD_IC || ic->kind() == Code::STORE_IC);
SerializeGeneric(ic, how_to_code, where_to_point);
}
int CodeSerializer::AddCodeStubKey(uint32_t stub_key) {
// TODO(yangguo) Maybe we need a hash table for a faster lookup than O(n^2).
int index = 0;
while (index < stub_keys_.length()) {
if (stub_keys_[index] == stub_key) return index;
index++;
}
stub_keys_.Add(stub_key);
return index;
}
MaybeHandle<SharedFunctionInfo> CodeSerializer::Deserialize(
Isolate* isolate, ScriptData* cached_data, Handle<String> source) {
base::ElapsedTimer timer;
if (FLAG_profile_deserialization) timer.Start();
HandleScope scope(isolate);
base::SmartPointer<SerializedCodeData> scd(
SerializedCodeData::FromCachedData(isolate, cached_data, *source));
if (scd.is_empty()) {
if (FLAG_profile_deserialization) PrintF("[Cached code failed check]\n");
DCHECK(cached_data->rejected());
return MaybeHandle<SharedFunctionInfo>();
}
// Prepare and register list of attached objects.
Vector<const uint32_t> code_stub_keys = scd->CodeStubKeys();
Vector<Handle<Object> > attached_objects = Vector<Handle<Object> >::New(
code_stub_keys.length() + kCodeStubsBaseIndex);
attached_objects[kSourceObjectIndex] = source;
for (int i = 0; i < code_stub_keys.length(); i++) {
attached_objects[i + kCodeStubsBaseIndex] =
CodeStub::GetCode(isolate, code_stub_keys[i]).ToHandleChecked();
}
Deserializer deserializer(scd.get());
deserializer.SetAttachedObjects(attached_objects);
// Deserialize.
Handle<SharedFunctionInfo> result;
if (!deserializer.DeserializeCode(isolate).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);
}
result->set_deserialized(true);
if (isolate->logger()->is_logging_code_events() ||
isolate->cpu_profiler()->is_profiling()) {
String* name = isolate->heap()->empty_string();
if (result->script()->IsScript()) {
Script* script = Script::cast(result->script());
if (script->name()->IsString()) name = String::cast(script->name());
}
isolate->logger()->CodeCreateEvent(Logger::SCRIPT_TAG, result->code(),
*result, NULL, name);
}
return scope.CloseAndEscape(result);
}
void SerializedData::AllocateData(int size) {
DCHECK(!owns_data_);
data_ = NewArray<byte>(size);
size_ = size;
owns_data_ = true;
DCHECK(IsAligned(reinterpret_cast<intptr_t>(data_), kPointerAlignment));
}
SnapshotData::SnapshotData(const Serializer& ser) {
DisallowHeapAllocation no_gc;
List<Reservation> reservations;
ser.EncodeReservations(&reservations);
const List<byte>& payload = ser.sink()->data();
// Calculate sizes.
int reservation_size = reservations.length() * kInt32Size;
int size = kHeaderSize + reservation_size + payload.length();
// Allocate backing store and create result data.
AllocateData(size);
// Set header values.
SetMagicNumber(ser.isolate());
SetHeaderValue(kCheckSumOffset, Version::Hash());
SetHeaderValue(kNumReservationsOffset, reservations.length());
SetHeaderValue(kPayloadLengthOffset, payload.length());
// Copy reservation chunk sizes.
CopyBytes(data_ + kHeaderSize, reinterpret_cast<byte*>(reservations.begin()),
reservation_size);
// Copy serialized data.
CopyBytes(data_ + kHeaderSize + reservation_size, payload.begin(),
static_cast<size_t>(payload.length()));
}
bool SnapshotData::IsSane() {
return GetHeaderValue(kCheckSumOffset) == Version::Hash();
}
Vector<const SerializedData::Reservation> SnapshotData::Reservations() const {
return Vector<const Reservation>(
reinterpret_cast<const Reservation*>(data_ + kHeaderSize),
GetHeaderValue(kNumReservationsOffset));
}
Vector<const byte> SnapshotData::Payload() const {
int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size;
const byte* payload = data_ + kHeaderSize + reservations_size;
int length = GetHeaderValue(kPayloadLengthOffset);
DCHECK_EQ(data_ + size_, payload + length);
return Vector<const byte>(payload, length);
}
class Checksum {
public:
explicit Checksum(Vector<const byte> payload) {
#ifdef MEMORY_SANITIZER
// Computing the checksum includes padding bytes for objects like strings.
// Mark every object as initialized in the code serializer.
MSAN_MEMORY_IS_INITIALIZED(payload.start(), payload.length());
#endif // MEMORY_SANITIZER
// Fletcher's checksum. Modified to reduce 64-bit sums to 32-bit.
uintptr_t a = 1;
uintptr_t b = 0;
const uintptr_t* cur = reinterpret_cast<const uintptr_t*>(payload.start());
DCHECK(IsAligned(payload.length(), kIntptrSize));
const uintptr_t* end = cur + payload.length() / kIntptrSize;
while (cur < end) {
// Unsigned overflow expected and intended.
a += *cur++;
b += a;
}
#if V8_HOST_ARCH_64_BIT
a ^= a >> 32;
b ^= b >> 32;
#endif // V8_HOST_ARCH_64_BIT
a_ = static_cast<uint32_t>(a);
b_ = static_cast<uint32_t>(b);
}
bool Check(uint32_t a, uint32_t b) const { return a == a_ && b == b_; }
uint32_t a() const { return a_; }
uint32_t b() const { return b_; }
private:
uint32_t a_;
uint32_t b_;
DISALLOW_COPY_AND_ASSIGN(Checksum);
};
SerializedCodeData::SerializedCodeData(const List<byte>& payload,
const CodeSerializer& cs) {
DisallowHeapAllocation no_gc;
const List<uint32_t>* stub_keys = cs.stub_keys();
List<Reservation> reservations;
cs.EncodeReservations(&reservations);
// Calculate sizes.
int reservation_size = reservations.length() * kInt32Size;
int num_stub_keys = stub_keys->length();
int stub_keys_size = stub_keys->length() * kInt32Size;
int payload_offset = kHeaderSize + reservation_size + stub_keys_size;
int padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
int size = padded_payload_offset + payload.length();
// Allocate backing store and create result data.
AllocateData(size);
// Set header values.
SetMagicNumber(cs.isolate());
SetHeaderValue(kVersionHashOffset, Version::Hash());
SetHeaderValue(kSourceHashOffset, SourceHash(cs.source()));
SetHeaderValue(kCpuFeaturesOffset,
static_cast<uint32_t>(CpuFeatures::SupportedFeatures()));
SetHeaderValue(kFlagHashOffset, FlagList::Hash());
SetHeaderValue(kNumReservationsOffset, reservations.length());
SetHeaderValue(kNumCodeStubKeysOffset, num_stub_keys);
SetHeaderValue(kPayloadLengthOffset, payload.length());
Checksum checksum(payload.ToConstVector());
SetHeaderValue(kChecksum1Offset, checksum.a());
SetHeaderValue(kChecksum2Offset, checksum.b());
// Copy reservation chunk sizes.
CopyBytes(data_ + kHeaderSize, reinterpret_cast<byte*>(reservations.begin()),
reservation_size);
// Copy code stub keys.
CopyBytes(data_ + kHeaderSize + reservation_size,
reinterpret_cast<byte*>(stub_keys->begin()), stub_keys_size);
memset(data_ + payload_offset, 0, padded_payload_offset - payload_offset);
// Copy serialized data.
CopyBytes(data_ + padded_payload_offset, payload.begin(),
static_cast<size_t>(payload.length()));
}
SerializedCodeData::SanityCheckResult SerializedCodeData::SanityCheck(
Isolate* isolate, String* source) const {
uint32_t magic_number = GetMagicNumber();
if (magic_number != ComputeMagicNumber(isolate)) return MAGIC_NUMBER_MISMATCH;
uint32_t version_hash = GetHeaderValue(kVersionHashOffset);
uint32_t source_hash = GetHeaderValue(kSourceHashOffset);
uint32_t cpu_features = GetHeaderValue(kCpuFeaturesOffset);
uint32_t flags_hash = GetHeaderValue(kFlagHashOffset);
uint32_t c1 = GetHeaderValue(kChecksum1Offset);
uint32_t c2 = GetHeaderValue(kChecksum2Offset);
if (version_hash != Version::Hash()) return VERSION_MISMATCH;
if (source_hash != SourceHash(source)) return SOURCE_MISMATCH;
if (cpu_features != static_cast<uint32_t>(CpuFeatures::SupportedFeatures())) {
return CPU_FEATURES_MISMATCH;
}
if (flags_hash != FlagList::Hash()) return FLAGS_MISMATCH;
if (!Checksum(Payload()).Check(c1, c2)) return CHECKSUM_MISMATCH;
return CHECK_SUCCESS;
}
uint32_t SerializedCodeData::SourceHash(String* source) const {
return source->length();
}
// 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_ = NULL;
return result;
}
Vector<const SerializedData::Reservation> SerializedCodeData::Reservations()
const {
return Vector<const Reservation>(
reinterpret_cast<const Reservation*>(data_ + kHeaderSize),
GetHeaderValue(kNumReservationsOffset));
}
Vector<const byte> SerializedCodeData::Payload() const {
int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size;
int code_stubs_size = GetHeaderValue(kNumCodeStubKeysOffset) * kInt32Size;
int payload_offset = kHeaderSize + reservations_size + code_stubs_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);
}
Vector<const uint32_t> SerializedCodeData::CodeStubKeys() const {
int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size;
const byte* start = data_ + kHeaderSize + reservations_size;
return Vector<const uint32_t>(reinterpret_cast<const uint32_t*>(start),
GetHeaderValue(kNumCodeStubKeysOffset));
}
SerializedCodeData::SerializedCodeData(ScriptData* data)
: SerializedData(const_cast<byte*>(data->data()), data->length()) {}
SerializedCodeData* SerializedCodeData::FromCachedData(Isolate* isolate,
ScriptData* cached_data,
String* source) {
DisallowHeapAllocation no_gc;
SerializedCodeData* scd = new SerializedCodeData(cached_data);
SanityCheckResult r = scd->SanityCheck(isolate, source);
if (r == CHECK_SUCCESS) return scd;
cached_data->Reject();
source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(r);
delete scd;
return NULL;
}
} // namespace internal
} // namespace v8