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