1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
|
// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/snapshot/code-serializer.h"
#include "src/codegen/macro-assembler.h"
#include "src/debug/debug.h"
#include "src/heap/heap-inl.h"
#include "src/logging/counters.h"
#include "src/logging/log.h"
#include "src/objects/objects-inl.h"
#include "src/objects/slots.h"
#include "src/objects/visitors.h"
#include "src/snapshot/object-deserializer.h"
#include "src/snapshot/snapshot.h"
#include "src/utils/version.h"
namespace v8 {
namespace internal {
ScriptData::ScriptData(const byte* data, int length)
: owns_data_(false), rejected_(false), data_(data), length_(length) {
if (!IsAligned(reinterpret_cast<intptr_t>(data), kPointerAlignment)) {
byte* copy = NewArray<byte>(length);
DCHECK(IsAligned(reinterpret_cast<intptr_t>(copy), kPointerAlignment));
CopyBytes(copy, data, length);
data_ = copy;
AcquireDataOwnership();
}
}
CodeSerializer::CodeSerializer(Isolate* isolate, uint32_t source_hash)
: Serializer(isolate), source_hash_(source_hash) {
allocator()->UseCustomChunkSize(FLAG_serialization_chunk_size);
}
// static
ScriptCompiler::CachedData* CodeSerializer::Serialize(
Handle<SharedFunctionInfo> info) {
Isolate* isolate = info->GetIsolate();
TRACE_EVENT_CALL_STATS_SCOPED(isolate, "v8", "V8.Execute");
HistogramTimerScope histogram_timer(isolate->counters()->compile_serialize());
RuntimeCallTimerScope runtimeTimer(isolate,
RuntimeCallCounterId::kCompileSerialize);
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.CompileSerialize");
base::ElapsedTimer timer;
if (FLAG_profile_deserialization) timer.Start();
Handle<Script> script(Script::cast(info->script()), isolate);
if (FLAG_trace_serializer) {
PrintF("[Serializing from");
script->name().ShortPrint();
PrintF("]\n");
}
// TODO(7110): Enable serialization of Asm modules once the AsmWasmData is
// context independent.
if (script->ContainsAsmModule()) return nullptr;
// Serialize code object.
Handle<String> source(String::cast(script->source()), isolate);
CodeSerializer cs(isolate, SerializedCodeData::SourceHash(
source, script->origin_options()));
DisallowHeapAllocation no_gc;
cs.reference_map()->AddAttachedReference(
reinterpret_cast<void*>(source->ptr()));
ScriptData* script_data = cs.SerializeSharedFunctionInfo(info);
if (FLAG_profile_deserialization) {
double ms = timer.Elapsed().InMillisecondsF();
int length = script_data->length();
PrintF("[Serializing to %d bytes took %0.3f ms]\n", length, ms);
}
ScriptCompiler::CachedData* result =
new ScriptCompiler::CachedData(script_data->data(), script_data->length(),
ScriptCompiler::CachedData::BufferOwned);
script_data->ReleaseDataOwnership();
delete script_data;
return result;
}
ScriptData* CodeSerializer::SerializeSharedFunctionInfo(
Handle<SharedFunctionInfo> info) {
DisallowHeapAllocation no_gc;
VisitRootPointer(Root::kHandleScope, nullptr,
FullObjectSlot(info.location()));
SerializeDeferredObjects();
Pad();
SerializedCodeData data(sink_.data(), this);
return data.GetScriptData();
}
bool CodeSerializer::SerializeReadOnlyObject(HeapObject obj) {
if (!ReadOnlyHeap::Contains(obj)) return false;
// For objects on the read-only heap, never serialize the object, but instead
// create a back reference that encodes the page number as the chunk_index and
// the offset within the page as the chunk_offset.
Address address = obj.address();
Page* page = Page::FromAddress(address);
uint32_t chunk_index = 0;
ReadOnlySpace* const read_only_space = isolate()->heap()->read_only_space();
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(
SnapshotSpace::kReadOnlyHeap, chunk_index, chunk_offset);
reference_map()->Add(reinterpret_cast<void*>(obj.ptr()), back_reference);
CHECK(SerializeBackReference(obj));
return true;
}
void CodeSerializer::SerializeObject(HeapObject obj) {
if (SerializeHotObject(obj)) return;
if (SerializeRoot(obj)) return;
if (SerializeBackReference(obj)) return;
if (SerializeReadOnlyObject(obj)) return;
CHECK(!obj.IsCode());
ReadOnlyRoots roots(isolate());
if (ElideObject(obj)) {
return SerializeObject(roots.undefined_value());
}
if (obj.IsScript()) {
Script script_obj = Script::cast(obj);
DCHECK_NE(script_obj.compilation_type(), Script::COMPILATION_TYPE_EVAL);
// We want to differentiate between undefined and uninitialized_symbol for
// context_data for now. It is hack to allow debugging for scripts that are
// included as a part of custom snapshot. (see debug::Script::IsEmbedded())
Object context_data = script_obj.context_data();
if (context_data != roots.undefined_value() &&
context_data != roots.uninitialized_symbol()) {
script_obj.set_context_data(roots.undefined_value());
}
// We don't want to serialize host options to avoid serializing unnecessary
// object graph.
FixedArray host_options = script_obj.host_defined_options();
script_obj.set_host_defined_options(roots.empty_fixed_array());
SerializeGeneric(obj);
script_obj.set_host_defined_options(host_options);
script_obj.set_context_data(context_data);
return;
}
if (obj.IsSharedFunctionInfo()) {
SharedFunctionInfo sfi = SharedFunctionInfo::cast(obj);
// TODO(7110): Enable serializing of Asm modules once the AsmWasmData
// is context independent.
DCHECK(!sfi.IsApiFunction() && !sfi.HasAsmWasmData());
DebugInfo debug_info;
BytecodeArray debug_bytecode_array;
if (sfi.HasDebugInfo()) {
// Clear debug info.
debug_info = sfi.GetDebugInfo();
if (debug_info.HasInstrumentedBytecodeArray()) {
debug_bytecode_array = debug_info.DebugBytecodeArray();
sfi.SetDebugBytecodeArray(debug_info.OriginalBytecodeArray());
}
sfi.set_script_or_debug_info(debug_info.script());
}
DCHECK(!sfi.HasDebugInfo());
SerializeGeneric(obj);
// Restore debug info
if (!debug_info.is_null()) {
sfi.set_script_or_debug_info(debug_info);
if (!debug_bytecode_array.is_null()) {
sfi.SetDebugBytecodeArray(debug_bytecode_array);
}
}
return;
}
// NOTE(mmarchini): If we try to serialize an InterpreterData our process
// will crash since it stores a code object. Instead, we serialize the
// bytecode array stored within the InterpreterData, which is the important
// information. On deserialization we'll create our code objects again, if
// --interpreted-frames-native-stack is on. See v8:9122 for more context
#ifndef V8_TARGET_ARCH_ARM
if (V8_UNLIKELY(FLAG_interpreted_frames_native_stack) &&
obj.IsInterpreterData()) {
obj = InterpreterData::cast(obj).bytecode_array();
}
#endif // V8_TARGET_ARCH_ARM
// Past this point we should not see any (context-specific) maps anymore.
CHECK(!obj.IsMap());
// There should be no references to the global object embedded.
CHECK(!obj.IsJSGlobalProxy() && !obj.IsJSGlobalObject());
// Embedded FixedArrays that need rehashing must support rehashing.
CHECK_IMPLIES(obj.NeedsRehashing(), obj.CanBeRehashed());
// We expect no instantiated function objects or contexts.
CHECK(!obj.IsJSFunction() && !obj.IsContext());
SerializeGeneric(obj);
}
void CodeSerializer::SerializeGeneric(HeapObject heap_object) {
// Object has not yet been serialized. Serialize it here.
ObjectSerializer serializer(this, heap_object, &sink_);
serializer.Serialize();
}
#ifndef V8_TARGET_ARCH_ARM
// NOTE(mmarchini): when FLAG_interpreted_frames_native_stack is on, we want to
// create duplicates of InterpreterEntryTrampoline for the deserialized
// functions, otherwise we'll call the builtin IET for those functions (which
// is not what a user of this flag wants).
void CreateInterpreterDataForDeserializedCode(Isolate* isolate,
Handle<SharedFunctionInfo> sfi,
bool log_code_creation) {
Handle<Script> script(Script::cast(sfi->script()), isolate);
String name = ReadOnlyRoots(isolate).empty_string();
if (script->name().IsString()) name = String::cast(script->name());
Handle<String> name_handle(name, isolate);
SharedFunctionInfo::ScriptIterator iter(isolate, *script);
for (SharedFunctionInfo shared_info = iter.Next(); !shared_info.is_null();
shared_info = iter.Next()) {
if (!shared_info.HasBytecodeArray()) continue;
Handle<SharedFunctionInfo> info = handle(shared_info, isolate);
Handle<Code> code = isolate->factory()->CopyCode(Handle<Code>::cast(
isolate->factory()->interpreter_entry_trampoline_for_profiling()));
Handle<InterpreterData> interpreter_data =
Handle<InterpreterData>::cast(isolate->factory()->NewStruct(
INTERPRETER_DATA_TYPE, AllocationType::kOld));
interpreter_data->set_bytecode_array(info->GetBytecodeArray());
interpreter_data->set_interpreter_trampoline(*code);
info->set_interpreter_data(*interpreter_data);
if (!log_code_creation) continue;
Handle<AbstractCode> abstract_code = Handle<AbstractCode>::cast(code);
int line_num = script->GetLineNumber(info->StartPosition()) + 1;
int column_num = script->GetColumnNumber(info->StartPosition()) + 1;
PROFILE(isolate,
CodeCreateEvent(CodeEventListener::INTERPRETED_FUNCTION_TAG,
abstract_code, info, name_handle, line_num,
column_num));
}
}
#endif // V8_TARGET_ARCH_ARM
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);
}
const bool log_code_creation =
isolate->logger()->is_listening_to_code_events() ||
isolate->is_profiling() ||
isolate->code_event_dispatcher()->IsListeningToCodeEvents();
#ifndef V8_TARGET_ARCH_ARM
if (V8_UNLIKELY(FLAG_interpreted_frames_native_stack))
CreateInterpreterDataForDeserializedCode(isolate, result,
log_code_creation);
#endif // V8_TARGET_ARCH_ARM
bool needs_source_positions = isolate->NeedsSourcePositionsForProfiling();
if (log_code_creation || FLAG_log_function_events) {
Handle<Script> script(Script::cast(result->script()), isolate);
Handle<String> name(script->name().IsString()
? String::cast(script->name())
: ReadOnlyRoots(isolate).empty_string(),
isolate);
if (FLAG_log_function_events) {
LOG(isolate,
FunctionEvent("deserialize", script->id(),
timer.Elapsed().InMillisecondsF(),
result->StartPosition(), result->EndPosition(), *name));
}
if (log_code_creation) {
Script::InitLineEnds(isolate, script);
SharedFunctionInfo::ScriptIterator iter(isolate, *script);
for (SharedFunctionInfo info = iter.Next(); !info.is_null();
info = iter.Next()) {
if (info.is_compiled()) {
Handle<SharedFunctionInfo> shared_info(info, isolate);
if (needs_source_positions) {
SharedFunctionInfo::EnsureSourcePositionsAvailable(isolate,
shared_info);
}
DisallowHeapAllocation no_gc;
int line_num =
script->GetLineNumber(shared_info->StartPosition()) + 1;
int column_num =
script->GetColumnNumber(shared_info->StartPosition()) + 1;
PROFILE(isolate,
CodeCreateEvent(CodeEventListener::SCRIPT_TAG,
handle(shared_info->abstract_code(), isolate),
shared_info, name, line_num, column_num));
}
}
}
}
if (needs_source_positions) {
Handle<Script> script(Script::cast(result->script()), isolate);
Script::InitLineEnds(isolate, script);
}
return scope.CloseAndEscape(result);
}
SerializedCodeData::SerializedCodeData(const std::vector<byte>* payload,
const CodeSerializer* cs) {
DisallowHeapAllocation no_gc;
std::vector<Reservation> reservations = cs->EncodeReservations();
// Calculate sizes.
uint32_t reservation_size =
static_cast<uint32_t>(reservations.size()) * kUInt32Size;
uint32_t num_stub_keys = 0; // TODO(jgruber): Remove.
uint32_t stub_keys_size = num_stub_keys * kUInt32Size;
uint32_t payload_offset = kHeaderSize + reservation_size + stub_keys_size;
uint32_t padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
uint32_t size =
padded_payload_offset + static_cast<uint32_t>(payload->size());
DCHECK(IsAligned(size, kPointerAlignment));
// Allocate backing store and create result data.
AllocateData(size);
// Zero out pre-payload data. Part of that is only used for padding.
memset(data_, 0, padded_payload_offset);
// Set header values.
SetMagicNumber();
SetHeaderValue(kVersionHashOffset, Version::Hash());
SetHeaderValue(kSourceHashOffset, cs->source_hash());
SetHeaderValue(kFlagHashOffset, FlagList::Hash());
SetHeaderValue(kNumReservationsOffset,
static_cast<uint32_t>(reservations.size()));
SetHeaderValue(kPayloadLengthOffset, static_cast<uint32_t>(payload->size()));
// Zero out any padding in the header.
memset(data_ + kUnalignedHeaderSize, 0, kHeaderSize - kUnalignedHeaderSize);
// Copy reservation chunk sizes.
CopyBytes(data_ + kHeaderSize,
reinterpret_cast<const byte*>(reservations.data()),
reservation_size);
// Copy serialized data.
CopyBytes(data_ + padded_payload_offset, payload->data(),
static_cast<size_t>(payload->size()));
SetHeaderValue(kChecksumOffset, Checksum(ChecksummedContent()));
}
SerializedCodeData::SanityCheckResult SerializedCodeData::SanityCheck(
Isolate* isolate, uint32_t expected_source_hash) const {
if (this->size_ < kHeaderSize) return INVALID_HEADER;
uint32_t magic_number = GetMagicNumber();
if (magic_number != kMagicNumber) return MAGIC_NUMBER_MISMATCH;
uint32_t version_hash = GetHeaderValue(kVersionHashOffset);
uint32_t source_hash = GetHeaderValue(kSourceHashOffset);
uint32_t flags_hash = GetHeaderValue(kFlagHashOffset);
uint32_t payload_length = GetHeaderValue(kPayloadLengthOffset);
uint32_t c = GetHeaderValue(kChecksumOffset);
if (version_hash != Version::Hash()) return VERSION_MISMATCH;
if (source_hash != expected_source_hash) return SOURCE_MISMATCH;
if (flags_hash != FlagList::Hash()) return FLAGS_MISMATCH;
uint32_t max_payload_length =
this->size_ -
POINTER_SIZE_ALIGN(kHeaderSize +
GetHeaderValue(kNumReservationsOffset) * kInt32Size);
if (payload_length > max_payload_length) return LENGTH_MISMATCH;
if (Checksum(ChecksummedContent()) != c) return CHECKSUM_MISMATCH;
return CHECK_SUCCESS;
}
uint32_t SerializedCodeData::SourceHash(Handle<String> source,
ScriptOriginOptions origin_options) {
const uint32_t source_length = source->length();
static constexpr uint32_t kModuleFlagMask = (1 << 31);
const uint32_t is_module = origin_options.IsModule() ? kModuleFlagMask : 0;
DCHECK_EQ(0, source_length & kModuleFlagMask);
return source_length | is_module;
}
// Return ScriptData object and relinquish ownership over it to the caller.
ScriptData* SerializedCodeData::GetScriptData() {
DCHECK(owns_data_);
ScriptData* result = new ScriptData(data_, size_);
result->AcquireDataOwnership();
owns_data_ = false;
data_ = nullptr;
return result;
}
std::vector<SerializedData::Reservation> SerializedCodeData::Reservations()
const {
uint32_t size = GetHeaderValue(kNumReservationsOffset);
std::vector<Reservation> reservations(size);
memcpy(reservations.data(), data_ + kHeaderSize,
size * sizeof(SerializedData::Reservation));
return reservations;
}
Vector<const byte> SerializedCodeData::Payload() const {
int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size;
int payload_offset = kHeaderSize + reservations_size;
int padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
const byte* payload = data_ + padded_payload_offset;
DCHECK(IsAligned(reinterpret_cast<intptr_t>(payload), kPointerAlignment));
int length = GetHeaderValue(kPayloadLengthOffset);
DCHECK_EQ(data_ + size_, payload + length);
return Vector<const byte>(payload, length);
}
SerializedCodeData::SerializedCodeData(ScriptData* data)
: SerializedData(const_cast<byte*>(data->data()), data->length()) {}
SerializedCodeData SerializedCodeData::FromCachedData(
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
|