1 // Copyright 2016 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "src/snapshot/deserializer.h" 6 7 #include "src/bootstrapper.h" 8 #include "src/external-reference-table.h" 9 #include "src/heap/heap.h" 10 #include "src/isolate.h" 11 #include "src/macro-assembler.h" 12 #include "src/snapshot/natives.h" 13 #include "src/v8.h" 14 15 namespace v8 { 16 namespace internal { 17 18 void Deserializer::DecodeReservation( 19 Vector<const SerializedData::Reservation> res) { 20 DCHECK_EQ(0, reservations_[NEW_SPACE].length()); 21 STATIC_ASSERT(NEW_SPACE == 0); 22 int current_space = NEW_SPACE; 23 for (auto& r : res) { 24 reservations_[current_space].Add({r.chunk_size(), NULL, NULL}); 25 if (r.is_last()) current_space++; 26 } 27 DCHECK_EQ(kNumberOfSpaces, current_space); 28 for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) current_chunk_[i] = 0; 29 } 30 31 void Deserializer::FlushICacheForNewIsolate() { 32 DCHECK(!deserializing_user_code_); 33 // The entire isolate is newly deserialized. Simply flush all code pages. 34 for (Page* p : *isolate_->heap()->code_space()) { 35 Assembler::FlushICache(isolate_, p->area_start(), 36 p->area_end() - p->area_start()); 37 } 38 } 39 40 void Deserializer::FlushICacheForNewCodeObjectsAndRecordEmbeddedObjects() { 41 DCHECK(deserializing_user_code_); 42 for (Code* code : new_code_objects_) { 43 // Record all references to embedded objects in the new code object. 44 isolate_->heap()->RecordWritesIntoCode(code); 45 46 if (FLAG_serialize_age_code) code->PreAge(isolate_); 47 Assembler::FlushICache(isolate_, code->instruction_start(), 48 code->instruction_size()); 49 } 50 } 51 52 bool Deserializer::ReserveSpace() { 53 #ifdef DEBUG 54 for (int i = NEW_SPACE; i < kNumberOfSpaces; ++i) { 55 CHECK(reservations_[i].length() > 0); 56 } 57 #endif // DEBUG 58 DCHECK(allocated_maps_.is_empty()); 59 if (!isolate_->heap()->ReserveSpace(reservations_, &allocated_maps_)) 60 return false; 61 for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) { 62 high_water_[i] = reservations_[i][0].start; 63 } 64 return true; 65 } 66 67 void Deserializer::Initialize(Isolate* isolate) { 68 DCHECK_NULL(isolate_); 69 DCHECK_NOT_NULL(isolate); 70 isolate_ = isolate; 71 DCHECK_NULL(external_reference_table_); 72 external_reference_table_ = ExternalReferenceTable::instance(isolate); 73 CHECK_EQ(magic_number_, 74 SerializedData::ComputeMagicNumber(external_reference_table_)); 75 } 76 77 void Deserializer::Deserialize(Isolate* isolate) { 78 Initialize(isolate); 79 if (!ReserveSpace()) V8::FatalProcessOutOfMemory("deserializing context"); 80 // No active threads. 81 DCHECK_NULL(isolate_->thread_manager()->FirstThreadStateInUse()); 82 // No active handles. 83 DCHECK(isolate_->handle_scope_implementer()->blocks()->is_empty()); 84 // Partial snapshot cache is not yet populated. 85 DCHECK(isolate_->partial_snapshot_cache()->is_empty()); 86 87 { 88 DisallowHeapAllocation no_gc; 89 isolate_->heap()->IterateStrongRoots(this, VISIT_ONLY_STRONG_ROOT_LIST); 90 isolate_->heap()->IterateSmiRoots(this); 91 isolate_->heap()->IterateStrongRoots(this, VISIT_ONLY_STRONG); 92 isolate_->heap()->RepairFreeListsAfterDeserialization(); 93 isolate_->heap()->IterateWeakRoots(this, VISIT_ALL); 94 DeserializeDeferredObjects(); 95 FlushICacheForNewIsolate(); 96 } 97 98 isolate_->heap()->set_native_contexts_list( 99 isolate_->heap()->undefined_value()); 100 // The allocation site list is build during root iteration, but if no sites 101 // were encountered then it needs to be initialized to undefined. 102 if (isolate_->heap()->allocation_sites_list() == Smi::kZero) { 103 isolate_->heap()->set_allocation_sites_list( 104 isolate_->heap()->undefined_value()); 105 } 106 107 // Issue code events for newly deserialized code objects. 108 LOG_CODE_EVENT(isolate_, LogCodeObjects()); 109 LOG_CODE_EVENT(isolate_, LogBytecodeHandlers()); 110 LOG_CODE_EVENT(isolate_, LogCompiledFunctions()); 111 } 112 113 MaybeHandle<Object> Deserializer::DeserializePartial( 114 Isolate* isolate, Handle<JSGlobalProxy> global_proxy) { 115 Initialize(isolate); 116 if (!ReserveSpace()) { 117 V8::FatalProcessOutOfMemory("deserialize context"); 118 return MaybeHandle<Object>(); 119 } 120 121 AddAttachedObject(global_proxy); 122 123 DisallowHeapAllocation no_gc; 124 // Keep track of the code space start and end pointers in case new 125 // code objects were unserialized 126 OldSpace* code_space = isolate_->heap()->code_space(); 127 Address start_address = code_space->top(); 128 Object* root; 129 VisitPointer(&root); 130 DeserializeDeferredObjects(); 131 DeserializeInternalFields(); 132 133 isolate->heap()->RegisterReservationsForBlackAllocation(reservations_); 134 135 // There's no code deserialized here. If this assert fires then that's 136 // changed and logging should be added to notify the profiler et al of the 137 // new code, which also has to be flushed from instruction cache. 138 CHECK_EQ(start_address, code_space->top()); 139 return Handle<Object>(root, isolate); 140 } 141 142 MaybeHandle<HeapObject> Deserializer::DeserializeObject(Isolate* isolate) { 143 Initialize(isolate); 144 if (!ReserveSpace()) { 145 return MaybeHandle<HeapObject>(); 146 } else { 147 deserializing_user_code_ = true; 148 HandleScope scope(isolate); 149 Handle<HeapObject> result; 150 { 151 DisallowHeapAllocation no_gc; 152 Object* root; 153 VisitPointer(&root); 154 DeserializeDeferredObjects(); 155 FlushICacheForNewCodeObjectsAndRecordEmbeddedObjects(); 156 result = Handle<HeapObject>(HeapObject::cast(root)); 157 isolate->heap()->RegisterReservationsForBlackAllocation(reservations_); 158 } 159 CommitPostProcessedObjects(isolate); 160 return scope.CloseAndEscape(result); 161 } 162 } 163 164 Deserializer::~Deserializer() { 165 // TODO(svenpanne) Re-enable this assertion when v8 initialization is fixed. 166 // DCHECK(source_.AtEOF()); 167 #ifdef DEBUG 168 for (int space = 0; space < kNumberOfPreallocatedSpaces; space++) { 169 int chunk_index = current_chunk_[space]; 170 CHECK_EQ(reservations_[space].length(), chunk_index + 1); 171 CHECK_EQ(reservations_[space][chunk_index].end, high_water_[space]); 172 } 173 CHECK_EQ(allocated_maps_.length(), next_map_index_); 174 #endif // DEBUG 175 } 176 177 // This is called on the roots. It is the driver of the deserialization 178 // process. It is also called on the body of each function. 179 void Deserializer::VisitPointers(Object** start, Object** end) { 180 // The space must be new space. Any other space would cause ReadChunk to try 181 // to update the remembered using NULL as the address. 182 ReadData(start, end, NEW_SPACE, NULL); 183 } 184 185 void Deserializer::Synchronize(VisitorSynchronization::SyncTag tag) { 186 static const byte expected = kSynchronize; 187 CHECK_EQ(expected, source_.Get()); 188 } 189 190 void Deserializer::DeserializeDeferredObjects() { 191 for (int code = source_.Get(); code != kSynchronize; code = source_.Get()) { 192 switch (code) { 193 case kAlignmentPrefix: 194 case kAlignmentPrefix + 1: 195 case kAlignmentPrefix + 2: 196 SetAlignment(code); 197 break; 198 default: { 199 int space = code & kSpaceMask; 200 DCHECK(space <= kNumberOfSpaces); 201 DCHECK(code - space == kNewObject); 202 HeapObject* object = GetBackReferencedObject(space); 203 int size = source_.GetInt() << kPointerSizeLog2; 204 Address obj_address = object->address(); 205 Object** start = reinterpret_cast<Object**>(obj_address + kPointerSize); 206 Object** end = reinterpret_cast<Object**>(obj_address + size); 207 bool filled = ReadData(start, end, space, obj_address); 208 CHECK(filled); 209 DCHECK(CanBeDeferred(object)); 210 PostProcessNewObject(object, space); 211 } 212 } 213 } 214 } 215 216 void Deserializer::DeserializeInternalFields() { 217 if (!source_.HasMore() || source_.Get() != kInternalFieldsData) return; 218 DisallowHeapAllocation no_gc; 219 DisallowJavascriptExecution no_js(isolate_); 220 DisallowCompilation no_compile(isolate_); 221 v8::DeserializeInternalFieldsCallback callback = 222 isolate_->deserialize_internal_fields_callback(); 223 DCHECK_NOT_NULL(callback); 224 for (int code = source_.Get(); code != kSynchronize; code = source_.Get()) { 225 HandleScope scope(isolate_); 226 int space = code & kSpaceMask; 227 DCHECK(space <= kNumberOfSpaces); 228 DCHECK(code - space == kNewObject); 229 Handle<JSObject> obj(JSObject::cast(GetBackReferencedObject(space)), 230 isolate_); 231 int index = source_.GetInt(); 232 int size = source_.GetInt(); 233 byte* data = new byte[size]; 234 source_.CopyRaw(data, size); 235 callback(v8::Utils::ToLocal(obj), index, 236 {reinterpret_cast<char*>(data), size}); 237 delete[] data; 238 } 239 } 240 241 // Used to insert a deserialized internalized string into the string table. 242 class StringTableInsertionKey : public HashTableKey { 243 public: 244 explicit StringTableInsertionKey(String* string) 245 : string_(string), hash_(HashForObject(string)) { 246 DCHECK(string->IsInternalizedString()); 247 } 248 249 bool IsMatch(Object* string) override { 250 // We know that all entries in a hash table had their hash keys created. 251 // Use that knowledge to have fast failure. 252 if (hash_ != HashForObject(string)) return false; 253 // We want to compare the content of two internalized strings here. 254 return string_->SlowEquals(String::cast(string)); 255 } 256 257 uint32_t Hash() override { return hash_; } 258 259 uint32_t HashForObject(Object* key) override { 260 return String::cast(key)->Hash(); 261 } 262 263 MUST_USE_RESULT Handle<Object> AsHandle(Isolate* isolate) override { 264 return handle(string_, isolate); 265 } 266 267 private: 268 String* string_; 269 uint32_t hash_; 270 DisallowHeapAllocation no_gc; 271 }; 272 273 HeapObject* Deserializer::PostProcessNewObject(HeapObject* obj, int space) { 274 if (deserializing_user_code()) { 275 if (obj->IsString()) { 276 String* string = String::cast(obj); 277 // Uninitialize hash field as the hash seed may have changed. 278 string->set_hash_field(String::kEmptyHashField); 279 if (string->IsInternalizedString()) { 280 // Canonicalize the internalized string. If it already exists in the 281 // string table, set it to forward to the existing one. 282 StringTableInsertionKey key(string); 283 String* canonical = StringTable::LookupKeyIfExists(isolate_, &key); 284 if (canonical == NULL) { 285 new_internalized_strings_.Add(handle(string)); 286 return string; 287 } else { 288 string->SetForwardedInternalizedString(canonical); 289 return canonical; 290 } 291 } 292 } else if (obj->IsScript()) { 293 new_scripts_.Add(handle(Script::cast(obj))); 294 } else { 295 DCHECK(CanBeDeferred(obj)); 296 } 297 } 298 if (obj->IsAllocationSite()) { 299 DCHECK(obj->IsAllocationSite()); 300 // Allocation sites are present in the snapshot, and must be linked into 301 // a list at deserialization time. 302 AllocationSite* site = AllocationSite::cast(obj); 303 // TODO(mvstanton): consider treating the heap()->allocation_sites_list() 304 // as a (weak) root. If this root is relocated correctly, this becomes 305 // unnecessary. 306 if (isolate_->heap()->allocation_sites_list() == Smi::kZero) { 307 site->set_weak_next(isolate_->heap()->undefined_value()); 308 } else { 309 site->set_weak_next(isolate_->heap()->allocation_sites_list()); 310 } 311 isolate_->heap()->set_allocation_sites_list(site); 312 } else if (obj->IsCode()) { 313 // We flush all code pages after deserializing the startup snapshot. In that 314 // case, we only need to remember code objects in the large object space. 315 // When deserializing user code, remember each individual code object. 316 if (deserializing_user_code() || space == LO_SPACE) { 317 new_code_objects_.Add(Code::cast(obj)); 318 } 319 } 320 // Check alignment. 321 DCHECK_EQ(0, Heap::GetFillToAlign(obj->address(), obj->RequiredAlignment())); 322 return obj; 323 } 324 325 void Deserializer::CommitPostProcessedObjects(Isolate* isolate) { 326 StringTable::EnsureCapacityForDeserialization( 327 isolate, new_internalized_strings_.length()); 328 for (Handle<String> string : new_internalized_strings_) { 329 StringTableInsertionKey key(*string); 330 DCHECK_NULL(StringTable::LookupKeyIfExists(isolate, &key)); 331 StringTable::LookupKey(isolate, &key); 332 } 333 334 Heap* heap = isolate->heap(); 335 Factory* factory = isolate->factory(); 336 for (Handle<Script> script : new_scripts_) { 337 // Assign a new script id to avoid collision. 338 script->set_id(isolate_->heap()->NextScriptId()); 339 // Add script to list. 340 Handle<Object> list = WeakFixedArray::Add(factory->script_list(), script); 341 heap->SetRootScriptList(*list); 342 } 343 } 344 345 HeapObject* Deserializer::GetBackReferencedObject(int space) { 346 HeapObject* obj; 347 SerializerReference back_reference = 348 SerializerReference::FromBitfield(source_.GetInt()); 349 if (space == LO_SPACE) { 350 uint32_t index = back_reference.large_object_index(); 351 obj = deserialized_large_objects_[index]; 352 } else if (space == MAP_SPACE) { 353 int index = back_reference.map_index(); 354 DCHECK(index < next_map_index_); 355 obj = HeapObject::FromAddress(allocated_maps_[index]); 356 } else { 357 DCHECK(space < kNumberOfPreallocatedSpaces); 358 uint32_t chunk_index = back_reference.chunk_index(); 359 DCHECK_LE(chunk_index, current_chunk_[space]); 360 uint32_t chunk_offset = back_reference.chunk_offset(); 361 Address address = reservations_[space][chunk_index].start + chunk_offset; 362 if (next_alignment_ != kWordAligned) { 363 int padding = Heap::GetFillToAlign(address, next_alignment_); 364 next_alignment_ = kWordAligned; 365 DCHECK(padding == 0 || HeapObject::FromAddress(address)->IsFiller()); 366 address += padding; 367 } 368 obj = HeapObject::FromAddress(address); 369 } 370 if (deserializing_user_code() && obj->IsInternalizedString()) { 371 obj = String::cast(obj)->GetForwardedInternalizedString(); 372 } 373 hot_objects_.Add(obj); 374 return obj; 375 } 376 377 // This routine writes the new object into the pointer provided and then 378 // returns true if the new object was in young space and false otherwise. 379 // The reason for this strange interface is that otherwise the object is 380 // written very late, which means the FreeSpace map is not set up by the 381 // time we need to use it to mark the space at the end of a page free. 382 void Deserializer::ReadObject(int space_number, Object** write_back) { 383 Address address; 384 HeapObject* obj; 385 int size = source_.GetInt() << kObjectAlignmentBits; 386 387 if (next_alignment_ != kWordAligned) { 388 int reserved = size + Heap::GetMaximumFillToAlign(next_alignment_); 389 address = Allocate(space_number, reserved); 390 obj = HeapObject::FromAddress(address); 391 // If one of the following assertions fails, then we are deserializing an 392 // aligned object when the filler maps have not been deserialized yet. 393 // We require filler maps as padding to align the object. 394 Heap* heap = isolate_->heap(); 395 DCHECK(heap->free_space_map()->IsMap()); 396 DCHECK(heap->one_pointer_filler_map()->IsMap()); 397 DCHECK(heap->two_pointer_filler_map()->IsMap()); 398 obj = heap->AlignWithFiller(obj, size, reserved, next_alignment_); 399 address = obj->address(); 400 next_alignment_ = kWordAligned; 401 } else { 402 address = Allocate(space_number, size); 403 obj = HeapObject::FromAddress(address); 404 } 405 406 isolate_->heap()->OnAllocationEvent(obj, size); 407 Object** current = reinterpret_cast<Object**>(address); 408 Object** limit = current + (size >> kPointerSizeLog2); 409 410 if (ReadData(current, limit, space_number, address)) { 411 // Only post process if object content has not been deferred. 412 obj = PostProcessNewObject(obj, space_number); 413 } 414 415 Object* write_back_obj = obj; 416 UnalignedCopy(write_back, &write_back_obj); 417 #ifdef DEBUG 418 if (obj->IsCode()) { 419 DCHECK(space_number == CODE_SPACE || space_number == LO_SPACE); 420 } else { 421 DCHECK(space_number != CODE_SPACE); 422 } 423 #endif // DEBUG 424 } 425 426 // We know the space requirements before deserialization and can 427 // pre-allocate that reserved space. During deserialization, all we need 428 // to do is to bump up the pointer for each space in the reserved 429 // space. This is also used for fixing back references. 430 // We may have to split up the pre-allocation into several chunks 431 // because it would not fit onto a single page. We do not have to keep 432 // track of when to move to the next chunk. An opcode will signal this. 433 // Since multiple large objects cannot be folded into one large object 434 // space allocation, we have to do an actual allocation when deserializing 435 // each large object. Instead of tracking offset for back references, we 436 // reference large objects by index. 437 Address Deserializer::Allocate(int space_index, int size) { 438 if (space_index == LO_SPACE) { 439 AlwaysAllocateScope scope(isolate_); 440 LargeObjectSpace* lo_space = isolate_->heap()->lo_space(); 441 Executability exec = static_cast<Executability>(source_.Get()); 442 AllocationResult result = lo_space->AllocateRaw(size, exec); 443 HeapObject* obj = result.ToObjectChecked(); 444 deserialized_large_objects_.Add(obj); 445 return obj->address(); 446 } else if (space_index == MAP_SPACE) { 447 DCHECK_EQ(Map::kSize, size); 448 return allocated_maps_[next_map_index_++]; 449 } else { 450 DCHECK(space_index < kNumberOfPreallocatedSpaces); 451 Address address = high_water_[space_index]; 452 DCHECK_NOT_NULL(address); 453 high_water_[space_index] += size; 454 #ifdef DEBUG 455 // Assert that the current reserved chunk is still big enough. 456 const Heap::Reservation& reservation = reservations_[space_index]; 457 int chunk_index = current_chunk_[space_index]; 458 CHECK_LE(high_water_[space_index], reservation[chunk_index].end); 459 #endif 460 if (space_index == CODE_SPACE) SkipList::Update(address, size); 461 return address; 462 } 463 } 464 465 Object** Deserializer::CopyInNativesSource(Vector<const char> source_vector, 466 Object** current) { 467 DCHECK(!isolate_->heap()->deserialization_complete()); 468 NativesExternalStringResource* resource = new NativesExternalStringResource( 469 source_vector.start(), source_vector.length()); 470 Object* resource_obj = reinterpret_cast<Object*>(resource); 471 UnalignedCopy(current++, &resource_obj); 472 return current; 473 } 474 475 bool Deserializer::ReadData(Object** current, Object** limit, int source_space, 476 Address current_object_address) { 477 Isolate* const isolate = isolate_; 478 // Write barrier support costs around 1% in startup time. In fact there 479 // are no new space objects in current boot snapshots, so it's not needed, 480 // but that may change. 481 bool write_barrier_needed = 482 (current_object_address != NULL && source_space != NEW_SPACE && 483 source_space != CODE_SPACE); 484 while (current < limit) { 485 byte data = source_.Get(); 486 switch (data) { 487 #define CASE_STATEMENT(where, how, within, space_number) \ 488 case where + how + within + space_number: \ 489 STATIC_ASSERT((where & ~kWhereMask) == 0); \ 490 STATIC_ASSERT((how & ~kHowToCodeMask) == 0); \ 491 STATIC_ASSERT((within & ~kWhereToPointMask) == 0); \ 492 STATIC_ASSERT((space_number & ~kSpaceMask) == 0); 493 494 #define CASE_BODY(where, how, within, space_number_if_any) \ 495 { \ 496 bool emit_write_barrier = false; \ 497 bool current_was_incremented = false; \ 498 int space_number = space_number_if_any == kAnyOldSpace \ 499 ? (data & kSpaceMask) \ 500 : space_number_if_any; \ 501 if (where == kNewObject && how == kPlain && within == kStartOfObject) { \ 502 ReadObject(space_number, current); \ 503 emit_write_barrier = (space_number == NEW_SPACE); \ 504 } else { \ 505 Object* new_object = NULL; /* May not be a real Object pointer. */ \ 506 if (where == kNewObject) { \ 507 ReadObject(space_number, &new_object); \ 508 } else if (where == kBackref) { \ 509 emit_write_barrier = (space_number == NEW_SPACE); \ 510 new_object = GetBackReferencedObject(data & kSpaceMask); \ 511 } else if (where == kBackrefWithSkip) { \ 512 int skip = source_.GetInt(); \ 513 current = reinterpret_cast<Object**>( \ 514 reinterpret_cast<Address>(current) + skip); \ 515 emit_write_barrier = (space_number == NEW_SPACE); \ 516 new_object = GetBackReferencedObject(data & kSpaceMask); \ 517 } else if (where == kRootArray) { \ 518 int id = source_.GetInt(); \ 519 Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(id); \ 520 new_object = isolate->heap()->root(root_index); \ 521 emit_write_barrier = isolate->heap()->InNewSpace(new_object); \ 522 hot_objects_.Add(HeapObject::cast(new_object)); \ 523 } else if (where == kPartialSnapshotCache) { \ 524 int cache_index = source_.GetInt(); \ 525 new_object = isolate->partial_snapshot_cache()->at(cache_index); \ 526 emit_write_barrier = isolate->heap()->InNewSpace(new_object); \ 527 } else if (where == kExternalReference) { \ 528 int skip = source_.GetInt(); \ 529 current = reinterpret_cast<Object**>( \ 530 reinterpret_cast<Address>(current) + skip); \ 531 uint32_t reference_id = static_cast<uint32_t>(source_.GetInt()); \ 532 Address address = external_reference_table_->address(reference_id); \ 533 new_object = reinterpret_cast<Object*>(address); \ 534 } else if (where == kAttachedReference) { \ 535 int index = source_.GetInt(); \ 536 new_object = *attached_objects_[index]; \ 537 emit_write_barrier = isolate->heap()->InNewSpace(new_object); \ 538 } else { \ 539 DCHECK(where == kBuiltin); \ 540 DCHECK(deserializing_user_code()); \ 541 int builtin_id = source_.GetInt(); \ 542 DCHECK_LE(0, builtin_id); \ 543 DCHECK_LT(builtin_id, Builtins::builtin_count); \ 544 Builtins::Name name = static_cast<Builtins::Name>(builtin_id); \ 545 new_object = isolate->builtins()->builtin(name); \ 546 emit_write_barrier = false; \ 547 } \ 548 if (within == kInnerPointer) { \ 549 if (new_object->IsCode()) { \ 550 Code* new_code_object = Code::cast(new_object); \ 551 new_object = \ 552 reinterpret_cast<Object*>(new_code_object->instruction_start()); \ 553 } else { \ 554 Cell* cell = Cell::cast(new_object); \ 555 new_object = reinterpret_cast<Object*>(cell->ValueAddress()); \ 556 } \ 557 } \ 558 if (how == kFromCode) { \ 559 Address location_of_branch_data = reinterpret_cast<Address>(current); \ 560 Assembler::deserialization_set_special_target_at( \ 561 isolate, location_of_branch_data, \ 562 Code::cast(HeapObject::FromAddress(current_object_address)), \ 563 reinterpret_cast<Address>(new_object)); \ 564 location_of_branch_data += Assembler::kSpecialTargetSize; \ 565 current = reinterpret_cast<Object**>(location_of_branch_data); \ 566 current_was_incremented = true; \ 567 } else { \ 568 UnalignedCopy(current, &new_object); \ 569 } \ 570 } \ 571 if (emit_write_barrier && write_barrier_needed) { \ 572 Address current_address = reinterpret_cast<Address>(current); \ 573 SLOW_DCHECK(isolate->heap()->ContainsSlow(current_object_address)); \ 574 isolate->heap()->RecordWrite( \ 575 HeapObject::FromAddress(current_object_address), \ 576 static_cast<int>(current_address - current_object_address), \ 577 *reinterpret_cast<Object**>(current_address)); \ 578 } \ 579 if (!current_was_incremented) { \ 580 current++; \ 581 } \ 582 break; \ 583 } 584 585 // This generates a case and a body for the new space (which has to do extra 586 // write barrier handling) and handles the other spaces with fall-through cases 587 // and one body. 588 #define ALL_SPACES(where, how, within) \ 589 CASE_STATEMENT(where, how, within, NEW_SPACE) \ 590 CASE_BODY(where, how, within, NEW_SPACE) \ 591 CASE_STATEMENT(where, how, within, OLD_SPACE) \ 592 CASE_STATEMENT(where, how, within, CODE_SPACE) \ 593 CASE_STATEMENT(where, how, within, MAP_SPACE) \ 594 CASE_STATEMENT(where, how, within, LO_SPACE) \ 595 CASE_BODY(where, how, within, kAnyOldSpace) 596 597 #define FOUR_CASES(byte_code) \ 598 case byte_code: \ 599 case byte_code + 1: \ 600 case byte_code + 2: \ 601 case byte_code + 3: 602 603 #define SIXTEEN_CASES(byte_code) \ 604 FOUR_CASES(byte_code) \ 605 FOUR_CASES(byte_code + 4) \ 606 FOUR_CASES(byte_code + 8) \ 607 FOUR_CASES(byte_code + 12) 608 609 #define SINGLE_CASE(where, how, within, space) \ 610 CASE_STATEMENT(where, how, within, space) \ 611 CASE_BODY(where, how, within, space) 612 613 // Deserialize a new object and write a pointer to it to the current 614 // object. 615 ALL_SPACES(kNewObject, kPlain, kStartOfObject) 616 // Support for direct instruction pointers in functions. It's an inner 617 // pointer because it points at the entry point, not at the start of the 618 // code object. 619 SINGLE_CASE(kNewObject, kPlain, kInnerPointer, CODE_SPACE) 620 // Support for pointers into a cell. It's an inner pointer because it 621 // points directly at the value field, not the start of the cell object. 622 SINGLE_CASE(kNewObject, kPlain, kInnerPointer, OLD_SPACE) 623 // Deserialize a new code object and write a pointer to its first 624 // instruction to the current code object. 625 ALL_SPACES(kNewObject, kFromCode, kInnerPointer) 626 // Find a recently deserialized object using its offset from the current 627 // allocation point and write a pointer to it to the current object. 628 ALL_SPACES(kBackref, kPlain, kStartOfObject) 629 ALL_SPACES(kBackrefWithSkip, kPlain, kStartOfObject) 630 #if V8_CODE_EMBEDS_OBJECT_POINTER 631 // Deserialize a new object from pointer found in code and write 632 // a pointer to it to the current object. Required only for MIPS, PPC, ARM 633 // or S390 with embedded constant pool, and omitted on the other 634 // architectures because it is fully unrolled and would cause bloat. 635 ALL_SPACES(kNewObject, kFromCode, kStartOfObject) 636 // Find a recently deserialized code object using its offset from the 637 // current allocation point and write a pointer to it to the current 638 // object. Required only for MIPS, PPC, ARM or S390 with embedded 639 // constant pool. 640 ALL_SPACES(kBackref, kFromCode, kStartOfObject) 641 ALL_SPACES(kBackrefWithSkip, kFromCode, kStartOfObject) 642 #endif 643 // Find a recently deserialized code object using its offset from the 644 // current allocation point and write a pointer to its first instruction 645 // to the current code object or the instruction pointer in a function 646 // object. 647 ALL_SPACES(kBackref, kFromCode, kInnerPointer) 648 ALL_SPACES(kBackrefWithSkip, kFromCode, kInnerPointer) 649 // Support for direct instruction pointers in functions. 650 SINGLE_CASE(kBackref, kPlain, kInnerPointer, CODE_SPACE) 651 SINGLE_CASE(kBackrefWithSkip, kPlain, kInnerPointer, CODE_SPACE) 652 // Support for pointers into a cell. 653 SINGLE_CASE(kBackref, kPlain, kInnerPointer, OLD_SPACE) 654 SINGLE_CASE(kBackrefWithSkip, kPlain, kInnerPointer, OLD_SPACE) 655 // Find an object in the roots array and write a pointer to it to the 656 // current object. 657 SINGLE_CASE(kRootArray, kPlain, kStartOfObject, 0) 658 #if V8_CODE_EMBEDS_OBJECT_POINTER 659 // Find an object in the roots array and write a pointer to it to in code. 660 SINGLE_CASE(kRootArray, kFromCode, kStartOfObject, 0) 661 #endif 662 // Find an object in the partial snapshots cache and write a pointer to it 663 // to the current object. 664 SINGLE_CASE(kPartialSnapshotCache, kPlain, kStartOfObject, 0) 665 // Find an code entry in the partial snapshots cache and 666 // write a pointer to it to the current object. 667 SINGLE_CASE(kPartialSnapshotCache, kPlain, kInnerPointer, 0) 668 // Find an external reference and write a pointer to it to the current 669 // object. 670 SINGLE_CASE(kExternalReference, kPlain, kStartOfObject, 0) 671 // Find an external reference and write a pointer to it in the current 672 // code object. 673 SINGLE_CASE(kExternalReference, kFromCode, kStartOfObject, 0) 674 // Find an object in the attached references and write a pointer to it to 675 // the current object. 676 SINGLE_CASE(kAttachedReference, kPlain, kStartOfObject, 0) 677 SINGLE_CASE(kAttachedReference, kPlain, kInnerPointer, 0) 678 SINGLE_CASE(kAttachedReference, kFromCode, kStartOfObject, 0) 679 SINGLE_CASE(kAttachedReference, kFromCode, kInnerPointer, 0) 680 // Find a builtin and write a pointer to it to the current object. 681 SINGLE_CASE(kBuiltin, kPlain, kStartOfObject, 0) 682 SINGLE_CASE(kBuiltin, kPlain, kInnerPointer, 0) 683 SINGLE_CASE(kBuiltin, kFromCode, kInnerPointer, 0) 684 685 #undef CASE_STATEMENT 686 #undef CASE_BODY 687 #undef ALL_SPACES 688 689 case kSkip: { 690 int size = source_.GetInt(); 691 current = reinterpret_cast<Object**>( 692 reinterpret_cast<intptr_t>(current) + size); 693 break; 694 } 695 696 case kInternalReferenceEncoded: 697 case kInternalReference: { 698 // Internal reference address is not encoded via skip, but by offset 699 // from code entry. 700 int pc_offset = source_.GetInt(); 701 int target_offset = source_.GetInt(); 702 Code* code = 703 Code::cast(HeapObject::FromAddress(current_object_address)); 704 DCHECK(0 <= pc_offset && pc_offset <= code->instruction_size()); 705 DCHECK(0 <= target_offset && target_offset <= code->instruction_size()); 706 Address pc = code->entry() + pc_offset; 707 Address target = code->entry() + target_offset; 708 Assembler::deserialization_set_target_internal_reference_at( 709 isolate, pc, target, data == kInternalReference 710 ? RelocInfo::INTERNAL_REFERENCE 711 : RelocInfo::INTERNAL_REFERENCE_ENCODED); 712 break; 713 } 714 715 case kNop: 716 break; 717 718 case kNextChunk: { 719 int space = source_.Get(); 720 DCHECK(space < kNumberOfPreallocatedSpaces); 721 int chunk_index = current_chunk_[space]; 722 const Heap::Reservation& reservation = reservations_[space]; 723 // Make sure the current chunk is indeed exhausted. 724 CHECK_EQ(reservation[chunk_index].end, high_water_[space]); 725 // Move to next reserved chunk. 726 chunk_index = ++current_chunk_[space]; 727 CHECK_LT(chunk_index, reservation.length()); 728 high_water_[space] = reservation[chunk_index].start; 729 break; 730 } 731 732 case kDeferred: { 733 // Deferred can only occur right after the heap object header. 734 DCHECK(current == reinterpret_cast<Object**>(current_object_address + 735 kPointerSize)); 736 HeapObject* obj = HeapObject::FromAddress(current_object_address); 737 // If the deferred object is a map, its instance type may be used 738 // during deserialization. Initialize it with a temporary value. 739 if (obj->IsMap()) Map::cast(obj)->set_instance_type(FILLER_TYPE); 740 current = limit; 741 return false; 742 } 743 744 case kSynchronize: 745 // If we get here then that indicates that you have a mismatch between 746 // the number of GC roots when serializing and deserializing. 747 CHECK(false); 748 break; 749 750 case kNativesStringResource: 751 current = CopyInNativesSource(Natives::GetScriptSource(source_.Get()), 752 current); 753 break; 754 755 case kExtraNativesStringResource: 756 current = CopyInNativesSource( 757 ExtraNatives::GetScriptSource(source_.Get()), current); 758 break; 759 760 // Deserialize raw data of variable length. 761 case kVariableRawData: { 762 int size_in_bytes = source_.GetInt(); 763 byte* raw_data_out = reinterpret_cast<byte*>(current); 764 source_.CopyRaw(raw_data_out, size_in_bytes); 765 break; 766 } 767 768 case kVariableRepeat: { 769 int repeats = source_.GetInt(); 770 Object* object = current[-1]; 771 DCHECK(!isolate->heap()->InNewSpace(object)); 772 for (int i = 0; i < repeats; i++) UnalignedCopy(current++, &object); 773 break; 774 } 775 776 case kAlignmentPrefix: 777 case kAlignmentPrefix + 1: 778 case kAlignmentPrefix + 2: 779 SetAlignment(data); 780 break; 781 782 STATIC_ASSERT(kNumberOfRootArrayConstants == Heap::kOldSpaceRoots); 783 STATIC_ASSERT(kNumberOfRootArrayConstants == 32); 784 SIXTEEN_CASES(kRootArrayConstantsWithSkip) 785 SIXTEEN_CASES(kRootArrayConstantsWithSkip + 16) { 786 int skip = source_.GetInt(); 787 current = reinterpret_cast<Object**>( 788 reinterpret_cast<intptr_t>(current) + skip); 789 // Fall through. 790 } 791 792 SIXTEEN_CASES(kRootArrayConstants) 793 SIXTEEN_CASES(kRootArrayConstants + 16) { 794 int id = data & kRootArrayConstantsMask; 795 Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(id); 796 Object* object = isolate->heap()->root(root_index); 797 DCHECK(!isolate->heap()->InNewSpace(object)); 798 UnalignedCopy(current++, &object); 799 break; 800 } 801 802 STATIC_ASSERT(kNumberOfHotObjects == 8); 803 FOUR_CASES(kHotObjectWithSkip) 804 FOUR_CASES(kHotObjectWithSkip + 4) { 805 int skip = source_.GetInt(); 806 current = reinterpret_cast<Object**>( 807 reinterpret_cast<Address>(current) + skip); 808 // Fall through. 809 } 810 811 FOUR_CASES(kHotObject) 812 FOUR_CASES(kHotObject + 4) { 813 int index = data & kHotObjectMask; 814 Object* hot_object = hot_objects_.Get(index); 815 UnalignedCopy(current, &hot_object); 816 if (write_barrier_needed && isolate->heap()->InNewSpace(hot_object)) { 817 Address current_address = reinterpret_cast<Address>(current); 818 isolate->heap()->RecordWrite( 819 HeapObject::FromAddress(current_object_address), 820 static_cast<int>(current_address - current_object_address), 821 hot_object); 822 } 823 current++; 824 break; 825 } 826 827 // Deserialize raw data of fixed length from 1 to 32 words. 828 STATIC_ASSERT(kNumberOfFixedRawData == 32); 829 SIXTEEN_CASES(kFixedRawData) 830 SIXTEEN_CASES(kFixedRawData + 16) { 831 byte* raw_data_out = reinterpret_cast<byte*>(current); 832 int size_in_bytes = (data - kFixedRawDataStart) << kPointerSizeLog2; 833 source_.CopyRaw(raw_data_out, size_in_bytes); 834 current = reinterpret_cast<Object**>(raw_data_out + size_in_bytes); 835 break; 836 } 837 838 STATIC_ASSERT(kNumberOfFixedRepeat == 16); 839 SIXTEEN_CASES(kFixedRepeat) { 840 int repeats = data - kFixedRepeatStart; 841 Object* object; 842 UnalignedCopy(&object, current - 1); 843 DCHECK(!isolate->heap()->InNewSpace(object)); 844 for (int i = 0; i < repeats; i++) UnalignedCopy(current++, &object); 845 break; 846 } 847 848 #undef SIXTEEN_CASES 849 #undef FOUR_CASES 850 #undef SINGLE_CASE 851 852 default: 853 CHECK(false); 854 } 855 } 856 CHECK_EQ(limit, current); 857 return true; 858 } 859 } // namespace internal 860 } // namespace v8 861
