blob: 5db7cae94b2b7a64601c7debb9f17e0e08bf4633 [file] [log] [blame]
// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/snapshot/code-serializer.h"
#include <memory>
#include "src/code-stubs.h"
#include "src/counters.h"
#include "src/debug/debug.h"
#include "src/log.h"
#include "src/macro-assembler.h"
#include "src/objects-inl.h"
#include "src/snapshot/object-deserializer.h"
#include "src/snapshot/snapshot.h"
#include "src/version.h"
#include "src/visitors.h"
namespace v8 {
namespace internal {
ScriptData::ScriptData(const byte* data, int length)
: owns_data_(false), rejected_(false), data_(data), length_(length) {
if (!IsAligned(reinterpret_cast<intptr_t>(data), kPointerAlignment)) {
byte* copy = NewArray<byte>(length);
DCHECK(IsAligned(reinterpret_cast<intptr_t>(copy), kPointerAlignment));
CopyBytes(copy, data, length);
data_ = copy;
AcquireDataOwnership();
}
}
CodeSerializer::CodeSerializer(Isolate* isolate, uint32_t source_hash)
: Serializer(isolate), source_hash_(source_hash) {
allocator()->UseCustomChunkSize(FLAG_serialization_chunk_size);
}
// static
ScriptCompiler::CachedData* CodeSerializer::Serialize(
Handle<SharedFunctionInfo> info) {
Isolate* isolate = info->GetIsolate();
TRACE_EVENT_CALL_STATS_SCOPED(isolate, "v8", "V8.Execute");
HistogramTimerScope histogram_timer(isolate->counters()->compile_serialize());
RuntimeCallTimerScope runtimeTimer(isolate,
RuntimeCallCounterId::kCompileSerialize);
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.CompileSerialize");
base::ElapsedTimer timer;
if (FLAG_profile_deserialization) timer.Start();
Handle<Script> script(Script::cast(info->script()), isolate);
if (FLAG_trace_serializer) {
PrintF("[Serializing from");
script->name()->ShortPrint();
PrintF("]\n");
}
// TODO(7110): Enable serialization of Asm modules once the AsmWasmData is
// context independent.
if (script->ContainsAsmModule()) return nullptr;
isolate->heap()->read_only_space()->ClearStringPaddingIfNeeded();
// Serialize code object.
Handle<String> source(String::cast(script->source()), isolate);
CodeSerializer cs(isolate, SerializedCodeData::SourceHash(
source, script->origin_options()));
DisallowHeapAllocation no_gc;
cs.reference_map()->AddAttachedReference(*source);
ScriptData* script_data = cs.SerializeSharedFunctionInfo(info);
if (FLAG_profile_deserialization) {
double ms = timer.Elapsed().InMillisecondsF();
int length = script_data->length();
PrintF("[Serializing to %d bytes took %0.3f ms]\n", length, ms);
}
ScriptCompiler::CachedData* result =
new ScriptCompiler::CachedData(script_data->data(), script_data->length(),
ScriptCompiler::CachedData::BufferOwned);
script_data->ReleaseDataOwnership();
delete script_data;
return result;
}
ScriptData* CodeSerializer::SerializeSharedFunctionInfo(
Handle<SharedFunctionInfo> info) {
DisallowHeapAllocation no_gc;
VisitRootPointer(Root::kHandleScope, nullptr,
Handle<Object>::cast(info).location());
SerializeDeferredObjects();
Pad();
SerializedCodeData data(sink_.data(), this);
return data.GetScriptData();
}
bool CodeSerializer::SerializeReadOnlyObject(HeapObject* obj,
HowToCode how_to_code,
WhereToPoint where_to_point,
int skip) {
PagedSpace* read_only_space = isolate()->heap()->read_only_space();
if (!read_only_space->Contains(obj)) return false;
// For objects in RO_SPACE, never serialize the object, but instead create a
// back reference that encodes the page number as the chunk_index and the
// offset within the page as the chunk_offset.
Address address = obj->address();
Page* page = Page::FromAddress(address);
uint32_t chunk_index = 0;
for (Page* p : *read_only_space) {
if (p == page) break;
++chunk_index;
}
uint32_t chunk_offset = static_cast<uint32_t>(page->Offset(address));
SerializerReference back_reference =
SerializerReference::BackReference(RO_SPACE, chunk_index, chunk_offset);
reference_map()->Add(obj, back_reference);
CHECK(SerializeBackReference(obj, how_to_code, where_to_point, skip));
return true;
}
void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
if (SerializeHotObject(obj, how_to_code, where_to_point, skip)) return;
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 (SerializeBackReference(obj, how_to_code, where_to_point, skip)) return;
if (SerializeReadOnlyObject(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::REGEXP: // No regexp literals initialized yet.
case Code::NUMBER_OF_KINDS: // Pseudo enum value.
case Code::BYTECODE_HANDLER: // No direct references to handlers.
break; // hit UNREACHABLE below.
case Code::BUILTIN:
SerializeBuiltinReference(code_object, how_to_code, where_to_point, 0);
return;
case Code::STUB:
if (code_object->builtin_index() == -1) {
SerializeCodeStub(code_object, how_to_code, where_to_point);
} else {
SerializeBuiltinReference(code_object, how_to_code, where_to_point,
0);
}
return;
default:
return SerializeCodeObject(code_object, how_to_code, where_to_point);
}
UNREACHABLE();
}
ReadOnlyRoots roots(isolate());
if (ElideObject(obj)) {
return SerializeObject(roots.undefined_value(), how_to_code, where_to_point,
skip);
}
if (obj->IsScript()) {
Script* script_obj = Script::cast(obj);
DCHECK_NE(script_obj->compilation_type(), Script::COMPILATION_TYPE_EVAL);
// We want to differentiate between undefined and uninitialized_symbol for
// context_data for now. It is hack to allow debugging for scripts that are
// included as a part of custom snapshot. (see debug::Script::IsEmbedded())
Object* context_data = script_obj->context_data();
if (context_data != roots.undefined_value() &&
context_data != roots.uninitialized_symbol()) {
script_obj->set_context_data(roots.undefined_value());
}
// We don't want to serialize host options to avoid serializing unnecessary
// object graph.
FixedArray* host_options = script_obj->host_defined_options();
script_obj->set_host_defined_options(roots.empty_fixed_array());
SerializeGeneric(obj, how_to_code, where_to_point);
script_obj->set_host_defined_options(host_options);
script_obj->set_context_data(context_data);
return;
}
if (obj->IsSharedFunctionInfo()) {
SharedFunctionInfo* sfi = SharedFunctionInfo::cast(obj);
// TODO(7110): Enable serializing of Asm modules once the AsmWasmData
// is context independent.
DCHECK(!sfi->IsApiFunction() && !sfi->HasAsmWasmData());
DebugInfo* debug_info = nullptr;
BytecodeArray* debug_bytecode_array = nullptr;
if (sfi->HasDebugInfo()) {
// Clear debug info.
debug_info = sfi->GetDebugInfo();
if (debug_info->HasInstrumentedBytecodeArray()) {
debug_bytecode_array = debug_info->DebugBytecodeArray();
sfi->SetDebugBytecodeArray(debug_info->OriginalBytecodeArray());
}
sfi->set_script_or_debug_info(debug_info->script());
}
DCHECK(!sfi->HasDebugInfo());
// Mark SFI to indicate whether the code is cached.
bool was_deserialized = sfi->deserialized();
sfi->set_deserialized(sfi->is_compiled());
SerializeGeneric(obj, how_to_code, where_to_point);
sfi->set_deserialized(was_deserialized);
// Restore debug info
if (debug_info != nullptr) {
sfi->set_script_or_debug_info(debug_info);
if (debug_bytecode_array != nullptr) {
sfi->SetDebugBytecodeArray(debug_bytecode_array);
}
}
return;
}
if (obj->IsBytecodeArray()) {
// Clear the stack frame cache if present
BytecodeArray::cast(obj)->ClearFrameCacheFromSourcePositionTable();
}
// Past this point we should not see any (context-specific) maps anymore.
CHECK(!obj->IsMap());
// There should be no references to the global object embedded.
CHECK(!obj->IsJSGlobalProxy() && !obj->IsJSGlobalObject());
// Embedded FixedArrays that need rehashing must support rehashing.
CHECK_IMPLIES(obj->NeedsRehashing(), obj->CanBeRehashed());
// We expect no instantiated function objects or contexts.
CHECK(!obj->IsJSFunction() && !obj->IsContext());
SerializeGeneric(obj, 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::SerializeCodeStub(Code* code_stub, HowToCode how_to_code,
WhereToPoint where_to_point) {
// We only arrive here if we have not encountered this code stub before.
DCHECK(!reference_map()->LookupReference(code_stub).is_valid());
uint32_t stub_key = code_stub->stub_key();
DCHECK(CodeStub::MajorKeyFromKey(stub_key) != CodeStub::NoCache);
DCHECK(!CodeStub::GetCode(isolate(), stub_key).is_null());
stub_keys_.push_back(stub_key);
SerializerReference reference =
reference_map()->AddAttachedReference(code_stub);
if (FLAG_trace_serializer) {
PrintF(" Encoding code stub %s as attached reference %d\n",
CodeStub::MajorName(CodeStub::MajorKeyFromKey(stub_key)),
reference.attached_reference_index());
}
PutAttachedReference(reference, how_to_code, where_to_point);
}
MaybeHandle<SharedFunctionInfo> CodeSerializer::Deserialize(
Isolate* isolate, ScriptData* cached_data, Handle<String> source,
ScriptOriginOptions origin_options) {
base::ElapsedTimer timer;
if (FLAG_profile_deserialization || FLAG_log_function_events) timer.Start();
HandleScope scope(isolate);
SerializedCodeData::SanityCheckResult sanity_check_result =
SerializedCodeData::CHECK_SUCCESS;
const SerializedCodeData scd = SerializedCodeData::FromCachedData(
isolate, cached_data,
SerializedCodeData::SourceHash(source, origin_options),
&sanity_check_result);
if (sanity_check_result != SerializedCodeData::CHECK_SUCCESS) {
if (FLAG_profile_deserialization) PrintF("[Cached code failed check]\n");
DCHECK(cached_data->rejected());
isolate->counters()->code_cache_reject_reason()->AddSample(
sanity_check_result);
return MaybeHandle<SharedFunctionInfo>();
}
// Deserialize.
MaybeHandle<SharedFunctionInfo> maybe_result =
ObjectDeserializer::DeserializeSharedFunctionInfo(isolate, &scd, source);
Handle<SharedFunctionInfo> result;
if (!maybe_result.ToHandle(&result)) {
// Deserializing may fail if the reservations cannot be fulfilled.
if (FLAG_profile_deserialization) PrintF("[Deserializing failed]\n");
return MaybeHandle<SharedFunctionInfo>();
}
if (FLAG_profile_deserialization) {
double ms = timer.Elapsed().InMillisecondsF();
int length = cached_data->length();
PrintF("[Deserializing from %d bytes took %0.3f ms]\n", length, ms);
}
bool log_code_creation = isolate->logger()->is_listening_to_code_events() ||
isolate->is_profiling();
if (log_code_creation || FLAG_log_function_events) {
String* name = ReadOnlyRoots(isolate).empty_string();
if (result->script()->IsScript()) {
Script* script = Script::cast(result->script());
if (script->name()->IsString()) name = String::cast(script->name());
if (FLAG_log_function_events) {
LOG(isolate, FunctionEvent("deserialize", script->id(),
timer.Elapsed().InMillisecondsF(),
result->StartPosition(),
result->EndPosition(), name));
}
}
if (log_code_creation) {
PROFILE(isolate, CodeCreateEvent(CodeEventListener::SCRIPT_TAG,
result->abstract_code(), *result, name));
}
}
if (isolate->NeedsSourcePositionsForProfiling()) {
Handle<Script> script(Script::cast(result->script()), isolate);
Script::InitLineEnds(script);
}
return scope.CloseAndEscape(result);
}
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 std::vector<byte>* payload,
const CodeSerializer* cs) {
DisallowHeapAllocation no_gc;
const std::vector<uint32_t>* stub_keys = cs->stub_keys();
std::vector<Reservation> reservations = cs->EncodeReservations();
// Calculate sizes.
uint32_t reservation_size =
static_cast<uint32_t>(reservations.size()) * kUInt32Size;
uint32_t num_stub_keys = static_cast<uint32_t>(stub_keys->size());
uint32_t stub_keys_size = num_stub_keys * kUInt32Size;
uint32_t payload_offset = kHeaderSize + reservation_size + stub_keys_size;
uint32_t padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
uint32_t size =
padded_payload_offset + static_cast<uint32_t>(payload->size());
// Allocate backing store and create result data.
AllocateData(size);
// Set header values.
SetMagicNumber(cs->isolate());
SetHeaderValue(kVersionHashOffset, Version::Hash());
SetHeaderValue(kSourceHashOffset, cs->source_hash());
SetHeaderValue(kCpuFeaturesOffset,
static_cast<uint32_t>(CpuFeatures::SupportedFeatures()));
SetHeaderValue(kFlagHashOffset, FlagList::Hash());
SetHeaderValue(kNumReservationsOffset,
static_cast<uint32_t>(reservations.size()));
SetHeaderValue(kNumCodeStubKeysOffset, num_stub_keys);
SetHeaderValue(kPayloadLengthOffset, static_cast<uint32_t>(payload->size()));
// Zero out any padding in the header.
memset(data_ + kUnalignedHeaderSize, 0, kHeaderSize - kUnalignedHeaderSize);
// Copy reservation chunk sizes.
CopyBytes(data_ + kHeaderSize,
reinterpret_cast<const byte*>(reservations.data()),
reservation_size);
// Copy code stub keys.
CopyBytes(data_ + kHeaderSize + reservation_size,
reinterpret_cast<const byte*>(stub_keys->data()), stub_keys_size);
// Zero out any padding before the payload.
memset(data_ + payload_offset, 0, padded_payload_offset - payload_offset);
// Copy serialized data.
CopyBytes(data_ + padded_payload_offset, payload->data(),
static_cast<size_t>(payload->size()));
Checksum checksum(DataWithoutHeader());
SetHeaderValue(kChecksum1Offset, checksum.a());
SetHeaderValue(kChecksum2Offset, checksum.b());
}
SerializedCodeData::SanityCheckResult SerializedCodeData::SanityCheck(
Isolate* isolate, uint32_t expected_source_hash) const {
if (this->size_ < kHeaderSize) return INVALID_HEADER;
uint32_t magic_number = GetMagicNumber();
if (magic_number != 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 payload_length = GetHeaderValue(kPayloadLengthOffset);
uint32_t c1 = GetHeaderValue(kChecksum1Offset);
uint32_t c2 = GetHeaderValue(kChecksum2Offset);
if (version_hash != Version::Hash()) return VERSION_MISMATCH;
if (source_hash != expected_source_hash) return SOURCE_MISMATCH;
if (cpu_features != static_cast<uint32_t>(CpuFeatures::SupportedFeatures())) {
return CPU_FEATURES_MISMATCH;
}
if (flags_hash != FlagList::Hash()) return FLAGS_MISMATCH;
uint32_t max_payload_length =
this->size_ -
POINTER_SIZE_ALIGN(kHeaderSize +
GetHeaderValue(kNumReservationsOffset) * kInt32Size +
GetHeaderValue(kNumCodeStubKeysOffset) * kInt32Size);
if (payload_length > max_payload_length) return LENGTH_MISMATCH;
if (!Checksum(DataWithoutHeader()).Check(c1, c2)) return CHECKSUM_MISMATCH;
return CHECK_SUCCESS;
}
uint32_t SerializedCodeData::SourceHash(Handle<String> source,
ScriptOriginOptions origin_options) {
const uint32_t source_length = source->length();
static constexpr uint32_t kModuleFlagMask = (1 << 31);
const uint32_t is_module = origin_options.IsModule() ? kModuleFlagMask : 0;
DCHECK_EQ(0, source_length & kModuleFlagMask);
return source_length | is_module;
}
// Return ScriptData object and relinquish ownership over it to the caller.
ScriptData* SerializedCodeData::GetScriptData() {
DCHECK(owns_data_);
ScriptData* result = new ScriptData(data_, size_);
result->AcquireDataOwnership();
owns_data_ = false;
data_ = nullptr;
return result;
}
std::vector<SerializedData::Reservation> SerializedCodeData::Reservations()
const {
uint32_t size = GetHeaderValue(kNumReservationsOffset);
std::vector<Reservation> reservations(size);
memcpy(reservations.data(), data_ + kHeaderSize,
size * sizeof(SerializedData::Reservation));
return reservations;
}
Vector<const byte> SerializedCodeData::Payload() const {
int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size;
int 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, uint32_t expected_source_hash,
SanityCheckResult* rejection_result) {
DisallowHeapAllocation no_gc;
SerializedCodeData scd(cached_data);
*rejection_result = scd.SanityCheck(isolate, expected_source_hash);
if (*rejection_result != CHECK_SUCCESS) {
cached_data->Reject();
return SerializedCodeData(nullptr, 0);
}
return scd;
}
} // namespace internal
} // namespace v8