1 // Copyright 2012 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 #ifndef V8_HEAP_HEAP_H_ 6 #define V8_HEAP_HEAP_H_ 7 8 #include <cmath> 9 #include <map> 10 11 // Clients of this interface shouldn't depend on lots of heap internals. 12 // Do not include anything from src/heap here! 13 #include "src/allocation.h" 14 #include "src/assert-scope.h" 15 #include "src/atomic-utils.h" 16 #include "src/globals.h" 17 // TODO(mstarzinger): Two more includes to kill! 18 #include "src/heap/spaces.h" 19 #include "src/heap/store-buffer.h" 20 #include "src/list.h" 21 22 namespace v8 { 23 namespace internal { 24 25 // Defines all the roots in Heap. 26 #define STRONG_ROOT_LIST(V) \ 27 V(Map, byte_array_map, ByteArrayMap) \ 28 V(Map, free_space_map, FreeSpaceMap) \ 29 V(Map, one_pointer_filler_map, OnePointerFillerMap) \ 30 V(Map, two_pointer_filler_map, TwoPointerFillerMap) \ 31 /* Cluster the most popular ones in a few cache lines here at the top. */ \ 32 V(Smi, store_buffer_top, StoreBufferTop) \ 33 V(Oddball, undefined_value, UndefinedValue) \ 34 V(Oddball, the_hole_value, TheHoleValue) \ 35 V(Oddball, null_value, NullValue) \ 36 V(Oddball, true_value, TrueValue) \ 37 V(Oddball, false_value, FalseValue) \ 38 V(String, empty_string, empty_string) \ 39 V(String, hidden_string, hidden_string) \ 40 V(Oddball, uninitialized_value, UninitializedValue) \ 41 V(Map, cell_map, CellMap) \ 42 V(Map, global_property_cell_map, GlobalPropertyCellMap) \ 43 V(Map, shared_function_info_map, SharedFunctionInfoMap) \ 44 V(Map, meta_map, MetaMap) \ 45 V(Map, heap_number_map, HeapNumberMap) \ 46 V(Map, mutable_heap_number_map, MutableHeapNumberMap) \ 47 V(Map, float32x4_map, Float32x4Map) \ 48 V(Map, int32x4_map, Int32x4Map) \ 49 V(Map, uint32x4_map, Uint32x4Map) \ 50 V(Map, bool32x4_map, Bool32x4Map) \ 51 V(Map, int16x8_map, Int16x8Map) \ 52 V(Map, uint16x8_map, Uint16x8Map) \ 53 V(Map, bool16x8_map, Bool16x8Map) \ 54 V(Map, int8x16_map, Int8x16Map) \ 55 V(Map, uint8x16_map, Uint8x16Map) \ 56 V(Map, bool8x16_map, Bool8x16Map) \ 57 V(Map, native_context_map, NativeContextMap) \ 58 V(Map, fixed_array_map, FixedArrayMap) \ 59 V(Map, code_map, CodeMap) \ 60 V(Map, scope_info_map, ScopeInfoMap) \ 61 V(Map, fixed_cow_array_map, FixedCOWArrayMap) \ 62 V(Map, fixed_double_array_map, FixedDoubleArrayMap) \ 63 V(Map, weak_cell_map, WeakCellMap) \ 64 V(Map, transition_array_map, TransitionArrayMap) \ 65 V(Map, one_byte_string_map, OneByteStringMap) \ 66 V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap) \ 67 V(Map, function_context_map, FunctionContextMap) \ 68 V(FixedArray, empty_fixed_array, EmptyFixedArray) \ 69 V(ByteArray, empty_byte_array, EmptyByteArray) \ 70 V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \ 71 /* The roots above this line should be boring from a GC point of view. */ \ 72 /* This means they are never in new space and never on a page that is */ \ 73 /* being compacted. */ \ 74 V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \ 75 V(Oddball, arguments_marker, ArgumentsMarker) \ 76 V(Oddball, exception, Exception) \ 77 V(Oddball, termination_exception, TerminationException) \ 78 V(FixedArray, number_string_cache, NumberStringCache) \ 79 V(Object, instanceof_cache_function, InstanceofCacheFunction) \ 80 V(Object, instanceof_cache_map, InstanceofCacheMap) \ 81 V(Object, instanceof_cache_answer, InstanceofCacheAnswer) \ 82 V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \ 83 V(FixedArray, string_split_cache, StringSplitCache) \ 84 V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \ 85 V(Smi, hash_seed, HashSeed) \ 86 V(Map, hash_table_map, HashTableMap) \ 87 V(Map, ordered_hash_table_map, OrderedHashTableMap) \ 88 V(Map, symbol_map, SymbolMap) \ 89 V(Map, string_map, StringMap) \ 90 V(Map, cons_one_byte_string_map, ConsOneByteStringMap) \ 91 V(Map, cons_string_map, ConsStringMap) \ 92 V(Map, sliced_string_map, SlicedStringMap) \ 93 V(Map, sliced_one_byte_string_map, SlicedOneByteStringMap) \ 94 V(Map, external_string_map, ExternalStringMap) \ 95 V(Map, external_string_with_one_byte_data_map, \ 96 ExternalStringWithOneByteDataMap) \ 97 V(Map, external_one_byte_string_map, ExternalOneByteStringMap) \ 98 V(Map, native_source_string_map, NativeSourceStringMap) \ 99 V(Map, short_external_string_map, ShortExternalStringMap) \ 100 V(Map, short_external_string_with_one_byte_data_map, \ 101 ShortExternalStringWithOneByteDataMap) \ 102 V(Map, internalized_string_map, InternalizedStringMap) \ 103 V(Map, external_internalized_string_map, ExternalInternalizedStringMap) \ 104 V(Map, external_internalized_string_with_one_byte_data_map, \ 105 ExternalInternalizedStringWithOneByteDataMap) \ 106 V(Map, external_one_byte_internalized_string_map, \ 107 ExternalOneByteInternalizedStringMap) \ 108 V(Map, short_external_internalized_string_map, \ 109 ShortExternalInternalizedStringMap) \ 110 V(Map, short_external_internalized_string_with_one_byte_data_map, \ 111 ShortExternalInternalizedStringWithOneByteDataMap) \ 112 V(Map, short_external_one_byte_internalized_string_map, \ 113 ShortExternalOneByteInternalizedStringMap) \ 114 V(Map, short_external_one_byte_string_map, ShortExternalOneByteStringMap) \ 115 V(Map, fixed_uint8_array_map, FixedUint8ArrayMap) \ 116 V(Map, fixed_int8_array_map, FixedInt8ArrayMap) \ 117 V(Map, fixed_uint16_array_map, FixedUint16ArrayMap) \ 118 V(Map, fixed_int16_array_map, FixedInt16ArrayMap) \ 119 V(Map, fixed_uint32_array_map, FixedUint32ArrayMap) \ 120 V(Map, fixed_int32_array_map, FixedInt32ArrayMap) \ 121 V(Map, fixed_float32_array_map, FixedFloat32ArrayMap) \ 122 V(Map, fixed_float64_array_map, FixedFloat64ArrayMap) \ 123 V(Map, fixed_uint8_clamped_array_map, FixedUint8ClampedArrayMap) \ 124 V(FixedTypedArrayBase, empty_fixed_uint8_array, EmptyFixedUint8Array) \ 125 V(FixedTypedArrayBase, empty_fixed_int8_array, EmptyFixedInt8Array) \ 126 V(FixedTypedArrayBase, empty_fixed_uint16_array, EmptyFixedUint16Array) \ 127 V(FixedTypedArrayBase, empty_fixed_int16_array, EmptyFixedInt16Array) \ 128 V(FixedTypedArrayBase, empty_fixed_uint32_array, EmptyFixedUint32Array) \ 129 V(FixedTypedArrayBase, empty_fixed_int32_array, EmptyFixedInt32Array) \ 130 V(FixedTypedArrayBase, empty_fixed_float32_array, EmptyFixedFloat32Array) \ 131 V(FixedTypedArrayBase, empty_fixed_float64_array, EmptyFixedFloat64Array) \ 132 V(FixedTypedArrayBase, empty_fixed_uint8_clamped_array, \ 133 EmptyFixedUint8ClampedArray) \ 134 V(Map, sloppy_arguments_elements_map, SloppyArgumentsElementsMap) \ 135 V(Map, catch_context_map, CatchContextMap) \ 136 V(Map, with_context_map, WithContextMap) \ 137 V(Map, block_context_map, BlockContextMap) \ 138 V(Map, module_context_map, ModuleContextMap) \ 139 V(Map, script_context_map, ScriptContextMap) \ 140 V(Map, script_context_table_map, ScriptContextTableMap) \ 141 V(Map, undefined_map, UndefinedMap) \ 142 V(Map, the_hole_map, TheHoleMap) \ 143 V(Map, null_map, NullMap) \ 144 V(Map, boolean_map, BooleanMap) \ 145 V(Map, uninitialized_map, UninitializedMap) \ 146 V(Map, arguments_marker_map, ArgumentsMarkerMap) \ 147 V(Map, no_interceptor_result_sentinel_map, NoInterceptorResultSentinelMap) \ 148 V(Map, exception_map, ExceptionMap) \ 149 V(Map, termination_exception_map, TerminationExceptionMap) \ 150 V(Map, message_object_map, JSMessageObjectMap) \ 151 V(Map, foreign_map, ForeignMap) \ 152 V(Map, neander_map, NeanderMap) \ 153 V(Map, external_map, ExternalMap) \ 154 V(HeapNumber, nan_value, NanValue) \ 155 V(HeapNumber, infinity_value, InfinityValue) \ 156 V(HeapNumber, minus_zero_value, MinusZeroValue) \ 157 V(HeapNumber, minus_infinity_value, MinusInfinityValue) \ 158 V(JSObject, message_listeners, MessageListeners) \ 159 V(UnseededNumberDictionary, code_stubs, CodeStubs) \ 160 V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache) \ 161 V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache) \ 162 V(Code, js_entry_code, JsEntryCode) \ 163 V(Code, js_construct_entry_code, JsConstructEntryCode) \ 164 V(FixedArray, natives_source_cache, NativesSourceCache) \ 165 V(FixedArray, experimental_natives_source_cache, \ 166 ExperimentalNativesSourceCache) \ 167 V(FixedArray, extra_natives_source_cache, ExtraNativesSourceCache) \ 168 V(FixedArray, experimental_extra_natives_source_cache, \ 169 ExperimentalExtraNativesSourceCache) \ 170 V(Script, empty_script, EmptyScript) \ 171 V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \ 172 V(NameDictionary, empty_properties_dictionary, EmptyPropertiesDictionary) \ 173 V(Cell, undefined_cell, UndefinedCell) \ 174 V(JSObject, observation_state, ObservationState) \ 175 V(Object, symbol_registry, SymbolRegistry) \ 176 V(Object, script_list, ScriptList) \ 177 V(SeededNumberDictionary, empty_slow_element_dictionary, \ 178 EmptySlowElementDictionary) \ 179 V(FixedArray, materialized_objects, MaterializedObjects) \ 180 V(FixedArray, microtask_queue, MicrotaskQueue) \ 181 V(TypeFeedbackVector, dummy_vector, DummyVector) \ 182 V(FixedArray, cleared_optimized_code_map, ClearedOptimizedCodeMap) \ 183 V(FixedArray, detached_contexts, DetachedContexts) \ 184 V(ArrayList, retained_maps, RetainedMaps) \ 185 V(WeakHashTable, weak_object_to_code_table, WeakObjectToCodeTable) \ 186 V(PropertyCell, array_protector, ArrayProtector) \ 187 V(PropertyCell, empty_property_cell, EmptyPropertyCell) \ 188 V(Object, weak_stack_trace_list, WeakStackTraceList) \ 189 V(Object, noscript_shared_function_infos, NoScriptSharedFunctionInfos) \ 190 V(FixedArray, interpreter_table, InterpreterTable) \ 191 V(Map, bytecode_array_map, BytecodeArrayMap) \ 192 V(WeakCell, empty_weak_cell, EmptyWeakCell) \ 193 V(BytecodeArray, empty_bytecode_array, EmptyBytecodeArray) 194 195 196 // Entries in this list are limited to Smis and are not visited during GC. 197 #define SMI_ROOT_LIST(V) \ 198 V(Smi, stack_limit, StackLimit) \ 199 V(Smi, real_stack_limit, RealStackLimit) \ 200 V(Smi, last_script_id, LastScriptId) \ 201 V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \ 202 V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset) \ 203 V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset) \ 204 V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset) 205 206 207 #define ROOT_LIST(V) \ 208 STRONG_ROOT_LIST(V) \ 209 SMI_ROOT_LIST(V) \ 210 V(StringTable, string_table, StringTable) 211 212 #define INTERNALIZED_STRING_LIST(V) \ 213 V(anonymous_string, "anonymous") \ 214 V(apply_string, "apply") \ 215 V(assign_string, "assign") \ 216 V(arguments_string, "arguments") \ 217 V(Arguments_string, "Arguments") \ 218 V(Array_string, "Array") \ 219 V(bind_string, "bind") \ 220 V(bool16x8_string, "bool16x8") \ 221 V(Bool16x8_string, "Bool16x8") \ 222 V(bool32x4_string, "bool32x4") \ 223 V(Bool32x4_string, "Bool32x4") \ 224 V(bool8x16_string, "bool8x16") \ 225 V(Bool8x16_string, "Bool8x16") \ 226 V(boolean_string, "boolean") \ 227 V(Boolean_string, "Boolean") \ 228 V(bound__string, "bound ") \ 229 V(byte_length_string, "byteLength") \ 230 V(byte_offset_string, "byteOffset") \ 231 V(call_string, "call") \ 232 V(callee_string, "callee") \ 233 V(caller_string, "caller") \ 234 V(cell_value_string, "%cell_value") \ 235 V(char_at_string, "CharAt") \ 236 V(closure_string, "(closure)") \ 237 V(compare_ic_string, "==") \ 238 V(configurable_string, "configurable") \ 239 V(constructor_string, "constructor") \ 240 V(construct_string, "construct") \ 241 V(create_string, "create") \ 242 V(Date_string, "Date") \ 243 V(default_string, "default") \ 244 V(defineProperty_string, "defineProperty") \ 245 V(deleteProperty_string, "deleteProperty") \ 246 V(display_name_string, "displayName") \ 247 V(done_string, "done") \ 248 V(dot_result_string, ".result") \ 249 V(dot_string, ".") \ 250 V(enumerable_string, "enumerable") \ 251 V(enumerate_string, "enumerate") \ 252 V(Error_string, "Error") \ 253 V(eval_string, "eval") \ 254 V(false_string, "false") \ 255 V(float32x4_string, "float32x4") \ 256 V(Float32x4_string, "Float32x4") \ 257 V(for_api_string, "for_api") \ 258 V(for_string, "for") \ 259 V(function_string, "function") \ 260 V(Function_string, "Function") \ 261 V(Generator_string, "Generator") \ 262 V(getOwnPropertyDescriptor_string, "getOwnPropertyDescriptor") \ 263 V(getPrototypeOf_string, "getPrototypeOf") \ 264 V(get_string, "get") \ 265 V(global_string, "global") \ 266 V(has_string, "has") \ 267 V(illegal_access_string, "illegal access") \ 268 V(illegal_argument_string, "illegal argument") \ 269 V(index_string, "index") \ 270 V(infinity_string, "Infinity") \ 271 V(input_string, "input") \ 272 V(int16x8_string, "int16x8") \ 273 V(Int16x8_string, "Int16x8") \ 274 V(int32x4_string, "int32x4") \ 275 V(Int32x4_string, "Int32x4") \ 276 V(int8x16_string, "int8x16") \ 277 V(Int8x16_string, "Int8x16") \ 278 V(isExtensible_string, "isExtensible") \ 279 V(isView_string, "isView") \ 280 V(KeyedLoadMonomorphic_string, "KeyedLoadMonomorphic") \ 281 V(KeyedStoreMonomorphic_string, "KeyedStoreMonomorphic") \ 282 V(last_index_string, "lastIndex") \ 283 V(length_string, "length") \ 284 V(Map_string, "Map") \ 285 V(minus_infinity_string, "-Infinity") \ 286 V(minus_zero_string, "-0") \ 287 V(name_string, "name") \ 288 V(nan_string, "NaN") \ 289 V(next_string, "next") \ 290 V(null_string, "null") \ 291 V(null_to_string, "[object Null]") \ 292 V(number_string, "number") \ 293 V(Number_string, "Number") \ 294 V(object_string, "object") \ 295 V(Object_string, "Object") \ 296 V(ownKeys_string, "ownKeys") \ 297 V(preventExtensions_string, "preventExtensions") \ 298 V(private_api_string, "private_api") \ 299 V(Promise_string, "Promise") \ 300 V(proto_string, "__proto__") \ 301 V(prototype_string, "prototype") \ 302 V(Proxy_string, "Proxy") \ 303 V(query_colon_string, "(?:)") \ 304 V(RegExp_string, "RegExp") \ 305 V(setPrototypeOf_string, "setPrototypeOf") \ 306 V(set_string, "set") \ 307 V(Set_string, "Set") \ 308 V(source_mapping_url_string, "source_mapping_url") \ 309 V(source_string, "source") \ 310 V(source_url_string, "source_url") \ 311 V(stack_string, "stack") \ 312 V(strict_compare_ic_string, "===") \ 313 V(string_string, "string") \ 314 V(String_string, "String") \ 315 V(symbol_string, "symbol") \ 316 V(Symbol_string, "Symbol") \ 317 V(this_string, "this") \ 318 V(throw_string, "throw") \ 319 V(toJSON_string, "toJSON") \ 320 V(toString_string, "toString") \ 321 V(true_string, "true") \ 322 V(uint16x8_string, "uint16x8") \ 323 V(Uint16x8_string, "Uint16x8") \ 324 V(uint32x4_string, "uint32x4") \ 325 V(Uint32x4_string, "Uint32x4") \ 326 V(uint8x16_string, "uint8x16") \ 327 V(Uint8x16_string, "Uint8x16") \ 328 V(undefined_string, "undefined") \ 329 V(undefined_to_string, "[object Undefined]") \ 330 V(valueOf_string, "valueOf") \ 331 V(value_string, "value") \ 332 V(WeakMap_string, "WeakMap") \ 333 V(WeakSet_string, "WeakSet") \ 334 V(writable_string, "writable") 335 336 #define PRIVATE_SYMBOL_LIST(V) \ 337 V(array_iteration_kind_symbol) \ 338 V(array_iterator_next_symbol) \ 339 V(array_iterator_object_symbol) \ 340 V(call_site_function_symbol) \ 341 V(call_site_position_symbol) \ 342 V(call_site_receiver_symbol) \ 343 V(call_site_strict_symbol) \ 344 V(class_end_position_symbol) \ 345 V(class_start_position_symbol) \ 346 V(detailed_stack_trace_symbol) \ 347 V(elements_transition_symbol) \ 348 V(error_end_pos_symbol) \ 349 V(error_script_symbol) \ 350 V(error_start_pos_symbol) \ 351 V(formatted_stack_trace_symbol) \ 352 V(frozen_symbol) \ 353 V(hash_code_symbol) \ 354 V(home_object_symbol) \ 355 V(internal_error_symbol) \ 356 V(intl_impl_object_symbol) \ 357 V(intl_initialized_marker_symbol) \ 358 V(intl_pattern_symbol) \ 359 V(intl_resolved_symbol) \ 360 V(megamorphic_symbol) \ 361 V(native_context_index_symbol) \ 362 V(nonexistent_symbol) \ 363 V(nonextensible_symbol) \ 364 V(normal_ic_symbol) \ 365 V(not_mapped_symbol) \ 366 V(observed_symbol) \ 367 V(premonomorphic_symbol) \ 368 V(promise_combined_deferred_symbol) \ 369 V(promise_debug_marker_symbol) \ 370 V(promise_has_handler_symbol) \ 371 V(promise_on_resolve_symbol) \ 372 V(promise_on_reject_symbol) \ 373 V(promise_raw_symbol) \ 374 V(promise_status_symbol) \ 375 V(promise_value_symbol) \ 376 V(sealed_symbol) \ 377 V(stack_trace_symbol) \ 378 V(strict_function_transition_symbol) \ 379 V(string_iterator_iterated_string_symbol) \ 380 V(string_iterator_next_index_symbol) \ 381 V(strong_function_transition_symbol) \ 382 V(uninitialized_symbol) 383 384 #define PUBLIC_SYMBOL_LIST(V) \ 385 V(has_instance_symbol, Symbol.hasInstance) \ 386 V(iterator_symbol, Symbol.iterator) \ 387 V(match_symbol, Symbol.match) \ 388 V(replace_symbol, Symbol.replace) \ 389 V(search_symbol, Symbol.search) \ 390 V(species_symbol, Symbol.species) \ 391 V(split_symbol, Symbol.split) \ 392 V(to_primitive_symbol, Symbol.toPrimitive) \ 393 V(unscopables_symbol, Symbol.unscopables) 394 395 // Well-Known Symbols are "Public" symbols, which have a bit set which causes 396 // them to produce an undefined value when a load results in a failed access 397 // check. Because this behaviour is not specified properly as of yet, it only 398 // applies to a subset of spec-defined Well-Known Symbols. 399 #define WELL_KNOWN_SYMBOL_LIST(V) \ 400 V(is_concat_spreadable_symbol, Symbol.isConcatSpreadable) \ 401 V(to_string_tag_symbol, Symbol.toStringTag) 402 403 // Heap roots that are known to be immortal immovable, for which we can safely 404 // skip write barriers. This list is not complete and has omissions. 405 #define IMMORTAL_IMMOVABLE_ROOT_LIST(V) \ 406 V(ByteArrayMap) \ 407 V(BytecodeArrayMap) \ 408 V(FreeSpaceMap) \ 409 V(OnePointerFillerMap) \ 410 V(TwoPointerFillerMap) \ 411 V(UndefinedValue) \ 412 V(TheHoleValue) \ 413 V(NullValue) \ 414 V(TrueValue) \ 415 V(FalseValue) \ 416 V(UninitializedValue) \ 417 V(CellMap) \ 418 V(GlobalPropertyCellMap) \ 419 V(SharedFunctionInfoMap) \ 420 V(MetaMap) \ 421 V(HeapNumberMap) \ 422 V(MutableHeapNumberMap) \ 423 V(Float32x4Map) \ 424 V(Int32x4Map) \ 425 V(Uint32x4Map) \ 426 V(Bool32x4Map) \ 427 V(Int16x8Map) \ 428 V(Uint16x8Map) \ 429 V(Bool16x8Map) \ 430 V(Int8x16Map) \ 431 V(Uint8x16Map) \ 432 V(Bool8x16Map) \ 433 V(NativeContextMap) \ 434 V(FixedArrayMap) \ 435 V(CodeMap) \ 436 V(ScopeInfoMap) \ 437 V(FixedCOWArrayMap) \ 438 V(FixedDoubleArrayMap) \ 439 V(WeakCellMap) \ 440 V(TransitionArrayMap) \ 441 V(NoInterceptorResultSentinel) \ 442 V(HashTableMap) \ 443 V(OrderedHashTableMap) \ 444 V(EmptyFixedArray) \ 445 V(EmptyByteArray) \ 446 V(EmptyBytecodeArray) \ 447 V(EmptyDescriptorArray) \ 448 V(ArgumentsMarker) \ 449 V(SymbolMap) \ 450 V(SloppyArgumentsElementsMap) \ 451 V(FunctionContextMap) \ 452 V(CatchContextMap) \ 453 V(WithContextMap) \ 454 V(BlockContextMap) \ 455 V(ModuleContextMap) \ 456 V(ScriptContextMap) \ 457 V(UndefinedMap) \ 458 V(TheHoleMap) \ 459 V(NullMap) \ 460 V(BooleanMap) \ 461 V(UninitializedMap) \ 462 V(ArgumentsMarkerMap) \ 463 V(JSMessageObjectMap) \ 464 V(ForeignMap) \ 465 V(NeanderMap) \ 466 V(EmptyWeakCell) \ 467 V(empty_string) \ 468 PRIVATE_SYMBOL_LIST(V) 469 470 // Forward declarations. 471 class ArrayBufferTracker; 472 class GCIdleTimeAction; 473 class GCIdleTimeHandler; 474 class GCIdleTimeHeapState; 475 class GCTracer; 476 class HeapObjectsFilter; 477 class HeapStats; 478 class HistogramTimer; 479 class Isolate; 480 class MemoryReducer; 481 class ObjectStats; 482 class Scavenger; 483 class ScavengeJob; 484 class WeakObjectRetainer; 485 486 487 // A queue of objects promoted during scavenge. Each object is accompanied 488 // by it's size to avoid dereferencing a map pointer for scanning. 489 // The last page in to-space is used for the promotion queue. On conflict 490 // during scavenge, the promotion queue is allocated externally and all 491 // entries are copied to the external queue. 492 class PromotionQueue { 493 public: 494 explicit PromotionQueue(Heap* heap) 495 : front_(NULL), 496 rear_(NULL), 497 limit_(NULL), 498 emergency_stack_(0), 499 heap_(heap) {} 500 501 void Initialize(); 502 503 void Destroy() { 504 DCHECK(is_empty()); 505 delete emergency_stack_; 506 emergency_stack_ = NULL; 507 } 508 509 Page* GetHeadPage() { 510 return Page::FromAllocationTop(reinterpret_cast<Address>(rear_)); 511 } 512 513 void SetNewLimit(Address limit) { 514 // If we are already using an emergency stack, we can ignore it. 515 if (emergency_stack_) return; 516 517 // If the limit is not on the same page, we can ignore it. 518 if (Page::FromAllocationTop(limit) != GetHeadPage()) return; 519 520 limit_ = reinterpret_cast<intptr_t*>(limit); 521 522 if (limit_ <= rear_) { 523 return; 524 } 525 526 RelocateQueueHead(); 527 } 528 529 bool IsBelowPromotionQueue(Address to_space_top) { 530 // If an emergency stack is used, the to-space address cannot interfere 531 // with the promotion queue. 532 if (emergency_stack_) return true; 533 534 // If the given to-space top pointer and the head of the promotion queue 535 // are not on the same page, then the to-space objects are below the 536 // promotion queue. 537 if (GetHeadPage() != Page::FromAddress(to_space_top)) { 538 return true; 539 } 540 // If the to space top pointer is smaller or equal than the promotion 541 // queue head, then the to-space objects are below the promotion queue. 542 return reinterpret_cast<intptr_t*>(to_space_top) <= rear_; 543 } 544 545 bool is_empty() { 546 return (front_ == rear_) && 547 (emergency_stack_ == NULL || emergency_stack_->length() == 0); 548 } 549 550 inline void insert(HeapObject* target, int size); 551 552 void remove(HeapObject** target, int* size) { 553 DCHECK(!is_empty()); 554 if (front_ == rear_) { 555 Entry e = emergency_stack_->RemoveLast(); 556 *target = e.obj_; 557 *size = e.size_; 558 return; 559 } 560 561 *target = reinterpret_cast<HeapObject*>(*(--front_)); 562 *size = static_cast<int>(*(--front_)); 563 // Assert no underflow. 564 SemiSpace::AssertValidRange(reinterpret_cast<Address>(rear_), 565 reinterpret_cast<Address>(front_)); 566 } 567 568 private: 569 // The front of the queue is higher in the memory page chain than the rear. 570 intptr_t* front_; 571 intptr_t* rear_; 572 intptr_t* limit_; 573 574 static const int kEntrySizeInWords = 2; 575 576 struct Entry { 577 Entry(HeapObject* obj, int size) : obj_(obj), size_(size) {} 578 579 HeapObject* obj_; 580 int size_; 581 }; 582 List<Entry>* emergency_stack_; 583 584 Heap* heap_; 585 586 void RelocateQueueHead(); 587 588 DISALLOW_COPY_AND_ASSIGN(PromotionQueue); 589 }; 590 591 592 enum ArrayStorageAllocationMode { 593 DONT_INITIALIZE_ARRAY_ELEMENTS, 594 INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE 595 }; 596 597 598 class Heap { 599 public: 600 // Declare all the root indices. This defines the root list order. 601 enum RootListIndex { 602 #define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex, 603 STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION) 604 #undef ROOT_INDEX_DECLARATION 605 606 #define STRING_INDEX_DECLARATION(name, str) k##name##RootIndex, 607 INTERNALIZED_STRING_LIST(STRING_INDEX_DECLARATION) 608 #undef STRING_DECLARATION 609 610 #define SYMBOL_INDEX_DECLARATION(name) k##name##RootIndex, 611 PRIVATE_SYMBOL_LIST(SYMBOL_INDEX_DECLARATION) 612 #undef SYMBOL_INDEX_DECLARATION 613 614 #define SYMBOL_INDEX_DECLARATION(name, description) k##name##RootIndex, 615 PUBLIC_SYMBOL_LIST(SYMBOL_INDEX_DECLARATION) 616 WELL_KNOWN_SYMBOL_LIST(SYMBOL_INDEX_DECLARATION) 617 #undef SYMBOL_INDEX_DECLARATION 618 619 // Utility type maps 620 #define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex, 621 STRUCT_LIST(DECLARE_STRUCT_MAP) 622 #undef DECLARE_STRUCT_MAP 623 kStringTableRootIndex, 624 625 #define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex, 626 SMI_ROOT_LIST(ROOT_INDEX_DECLARATION) 627 #undef ROOT_INDEX_DECLARATION 628 kRootListLength, 629 kStrongRootListLength = kStringTableRootIndex, 630 kSmiRootsStart = kStringTableRootIndex + 1 631 }; 632 633 // Indicates whether live bytes adjustment is triggered 634 // - from within the GC code before sweeping started (SEQUENTIAL_TO_SWEEPER), 635 // - or from within GC (CONCURRENT_TO_SWEEPER), 636 // - or mutator code (CONCURRENT_TO_SWEEPER). 637 enum InvocationMode { SEQUENTIAL_TO_SWEEPER, CONCURRENT_TO_SWEEPER }; 638 639 enum PretenuringFeedbackInsertionMode { kCached, kGlobal }; 640 641 enum HeapState { NOT_IN_GC, SCAVENGE, MARK_COMPACT }; 642 643 // Taking this lock prevents the GC from entering a phase that relocates 644 // object references. 645 class RelocationLock { 646 public: 647 explicit RelocationLock(Heap* heap) : heap_(heap) { 648 heap_->relocation_mutex_.Lock(); 649 } 650 651 ~RelocationLock() { heap_->relocation_mutex_.Unlock(); } 652 653 private: 654 Heap* heap_; 655 }; 656 657 // Support for partial snapshots. After calling this we have a linear 658 // space to write objects in each space. 659 struct Chunk { 660 uint32_t size; 661 Address start; 662 Address end; 663 }; 664 typedef List<Chunk> Reservation; 665 666 static const intptr_t kMinimumOldGenerationAllocationLimit = 667 8 * (Page::kPageSize > MB ? Page::kPageSize : MB); 668 669 static const int kInitalOldGenerationLimitFactor = 2; 670 671 #if V8_OS_ANDROID 672 // Don't apply pointer multiplier on Android since it has no swap space and 673 // should instead adapt it's heap size based on available physical memory. 674 static const int kPointerMultiplier = 1; 675 #else 676 static const int kPointerMultiplier = i::kPointerSize / 4; 677 #endif 678 679 // The new space size has to be a power of 2. Sizes are in MB. 680 static const int kMaxSemiSpaceSizeLowMemoryDevice = 1 * kPointerMultiplier; 681 static const int kMaxSemiSpaceSizeMediumMemoryDevice = 4 * kPointerMultiplier; 682 static const int kMaxSemiSpaceSizeHighMemoryDevice = 8 * kPointerMultiplier; 683 static const int kMaxSemiSpaceSizeHugeMemoryDevice = 8 * kPointerMultiplier; 684 685 // The old space size has to be a multiple of Page::kPageSize. 686 // Sizes are in MB. 687 static const int kMaxOldSpaceSizeLowMemoryDevice = 128 * kPointerMultiplier; 688 static const int kMaxOldSpaceSizeMediumMemoryDevice = 689 256 * kPointerMultiplier; 690 static const int kMaxOldSpaceSizeHighMemoryDevice = 512 * kPointerMultiplier; 691 static const int kMaxOldSpaceSizeHugeMemoryDevice = 700 * kPointerMultiplier; 692 693 // The executable size has to be a multiple of Page::kPageSize. 694 // Sizes are in MB. 695 static const int kMaxExecutableSizeLowMemoryDevice = 96 * kPointerMultiplier; 696 static const int kMaxExecutableSizeMediumMemoryDevice = 697 192 * kPointerMultiplier; 698 static const int kMaxExecutableSizeHighMemoryDevice = 699 256 * kPointerMultiplier; 700 static const int kMaxExecutableSizeHugeMemoryDevice = 701 256 * kPointerMultiplier; 702 703 static const int kTraceRingBufferSize = 512; 704 static const int kStacktraceBufferSize = 512; 705 706 static const double kMinHeapGrowingFactor; 707 static const double kMaxHeapGrowingFactor; 708 static const double kMaxHeapGrowingFactorMemoryConstrained; 709 static const double kMaxHeapGrowingFactorIdle; 710 static const double kTargetMutatorUtilization; 711 712 // Sloppy mode arguments object size. 713 static const int kSloppyArgumentsObjectSize = 714 JSObject::kHeaderSize + 2 * kPointerSize; 715 716 // Strict mode arguments has no callee so it is smaller. 717 static const int kStrictArgumentsObjectSize = 718 JSObject::kHeaderSize + 1 * kPointerSize; 719 720 // Indicies for direct access into argument objects. 721 static const int kArgumentsLengthIndex = 0; 722 723 // callee is only valid in sloppy mode. 724 static const int kArgumentsCalleeIndex = 1; 725 726 static const int kNoGCFlags = 0; 727 static const int kReduceMemoryFootprintMask = 1; 728 static const int kAbortIncrementalMarkingMask = 2; 729 static const int kFinalizeIncrementalMarkingMask = 4; 730 731 // Making the heap iterable requires us to abort incremental marking. 732 static const int kMakeHeapIterableMask = kAbortIncrementalMarkingMask; 733 734 // The roots that have an index less than this are always in old space. 735 static const int kOldSpaceRoots = 0x20; 736 737 // The minimum size of a HeapObject on the heap. 738 static const int kMinObjectSizeInWords = 2; 739 740 STATIC_ASSERT(kUndefinedValueRootIndex == 741 Internals::kUndefinedValueRootIndex); 742 STATIC_ASSERT(kNullValueRootIndex == Internals::kNullValueRootIndex); 743 STATIC_ASSERT(kTrueValueRootIndex == Internals::kTrueValueRootIndex); 744 STATIC_ASSERT(kFalseValueRootIndex == Internals::kFalseValueRootIndex); 745 STATIC_ASSERT(kempty_stringRootIndex == Internals::kEmptyStringRootIndex); 746 747 // Calculates the maximum amount of filler that could be required by the 748 // given alignment. 749 static int GetMaximumFillToAlign(AllocationAlignment alignment); 750 // Calculates the actual amount of filler required for a given address at the 751 // given alignment. 752 static int GetFillToAlign(Address address, AllocationAlignment alignment); 753 754 template <typename T> 755 static inline bool IsOneByte(T t, int chars); 756 757 static void FatalProcessOutOfMemory(const char* location, 758 bool take_snapshot = false); 759 760 static bool RootIsImmortalImmovable(int root_index); 761 762 // Checks whether the space is valid. 763 static bool IsValidAllocationSpace(AllocationSpace space); 764 765 // Generated code can embed direct references to non-writable roots if 766 // they are in new space. 767 static bool RootCanBeWrittenAfterInitialization(RootListIndex root_index); 768 769 // Zapping is needed for verify heap, and always done in debug builds. 770 static inline bool ShouldZapGarbage() { 771 #ifdef DEBUG 772 return true; 773 #else 774 #ifdef VERIFY_HEAP 775 return FLAG_verify_heap; 776 #else 777 return false; 778 #endif 779 #endif 780 } 781 782 static double HeapGrowingFactor(double gc_speed, double mutator_speed); 783 784 // Copy block of memory from src to dst. Size of block should be aligned 785 // by pointer size. 786 static inline void CopyBlock(Address dst, Address src, int byte_size); 787 788 // Optimized version of memmove for blocks with pointer size aligned sizes and 789 // pointer size aligned addresses. 790 static inline void MoveBlock(Address dst, Address src, int byte_size); 791 792 // Determines a static visitor id based on the given {map} that can then be 793 // stored on the map to facilitate fast dispatch for {StaticVisitorBase}. 794 static int GetStaticVisitorIdForMap(Map* map); 795 796 // Notifies the heap that is ok to start marking or other activities that 797 // should not happen during deserialization. 798 void NotifyDeserializationComplete(); 799 800 intptr_t old_generation_allocation_limit() const { 801 return old_generation_allocation_limit_; 802 } 803 804 bool always_allocate() { return always_allocate_scope_count_.Value() != 0; } 805 806 Address* NewSpaceAllocationTopAddress() { 807 return new_space_.allocation_top_address(); 808 } 809 Address* NewSpaceAllocationLimitAddress() { 810 return new_space_.allocation_limit_address(); 811 } 812 813 Address* OldSpaceAllocationTopAddress() { 814 return old_space_->allocation_top_address(); 815 } 816 Address* OldSpaceAllocationLimitAddress() { 817 return old_space_->allocation_limit_address(); 818 } 819 820 // TODO(hpayer): There is still a missmatch between capacity and actual 821 // committed memory size. 822 bool CanExpandOldGeneration(int size = 0) { 823 if (force_oom_) return false; 824 return (CommittedOldGenerationMemory() + size) < MaxOldGenerationSize(); 825 } 826 827 // Clear the Instanceof cache (used when a prototype changes). 828 inline void ClearInstanceofCache(); 829 830 // FreeSpace objects have a null map after deserialization. Update the map. 831 void RepairFreeListsAfterDeserialization(); 832 833 // Move len elements within a given array from src_index index to dst_index 834 // index. 835 void MoveElements(FixedArray* array, int dst_index, int src_index, int len); 836 837 // Initialize a filler object to keep the ability to iterate over the heap 838 // when introducing gaps within pages. 839 void CreateFillerObjectAt(Address addr, int size); 840 841 bool CanMoveObjectStart(HeapObject* object); 842 843 // Maintain consistency of live bytes during incremental marking. 844 void AdjustLiveBytes(HeapObject* object, int by, InvocationMode mode); 845 846 // Trim the given array from the left. Note that this relocates the object 847 // start and hence is only valid if there is only a single reference to it. 848 FixedArrayBase* LeftTrimFixedArray(FixedArrayBase* obj, int elements_to_trim); 849 850 // Trim the given array from the right. 851 template<Heap::InvocationMode mode> 852 void RightTrimFixedArray(FixedArrayBase* obj, int elements_to_trim); 853 854 // Converts the given boolean condition to JavaScript boolean value. 855 inline Object* ToBoolean(bool condition); 856 857 // Check whether the heap is currently iterable. 858 bool IsHeapIterable(); 859 860 // Notify the heap that a context has been disposed. 861 int NotifyContextDisposed(bool dependant_context); 862 863 inline void increment_scan_on_scavenge_pages() { 864 scan_on_scavenge_pages_++; 865 if (FLAG_gc_verbose) { 866 PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_); 867 } 868 } 869 870 inline void decrement_scan_on_scavenge_pages() { 871 scan_on_scavenge_pages_--; 872 if (FLAG_gc_verbose) { 873 PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_); 874 } 875 } 876 877 void set_native_contexts_list(Object* object) { 878 native_contexts_list_ = object; 879 } 880 Object* native_contexts_list() const { return native_contexts_list_; } 881 882 void set_allocation_sites_list(Object* object) { 883 allocation_sites_list_ = object; 884 } 885 Object* allocation_sites_list() { return allocation_sites_list_; } 886 887 // Used in CreateAllocationSiteStub and the (de)serializer. 888 Object** allocation_sites_list_address() { return &allocation_sites_list_; } 889 890 void set_encountered_weak_collections(Object* weak_collection) { 891 encountered_weak_collections_ = weak_collection; 892 } 893 Object* encountered_weak_collections() const { 894 return encountered_weak_collections_; 895 } 896 897 void set_encountered_weak_cells(Object* weak_cell) { 898 encountered_weak_cells_ = weak_cell; 899 } 900 Object* encountered_weak_cells() const { return encountered_weak_cells_; } 901 902 void set_encountered_transition_arrays(Object* transition_array) { 903 encountered_transition_arrays_ = transition_array; 904 } 905 Object* encountered_transition_arrays() const { 906 return encountered_transition_arrays_; 907 } 908 909 // Number of mark-sweeps. 910 int ms_count() const { return ms_count_; } 911 912 // Checks whether the given object is allowed to be migrated from it's 913 // current space into the given destination space. Used for debugging. 914 inline bool AllowedToBeMigrated(HeapObject* object, AllocationSpace dest); 915 916 void CheckHandleCount(); 917 918 // Number of "runtime allocations" done so far. 919 uint32_t allocations_count() { return allocations_count_; } 920 921 // Print short heap statistics. 922 void PrintShortHeapStatistics(); 923 924 inline HeapState gc_state() { return gc_state_; } 925 926 inline bool IsInGCPostProcessing() { return gc_post_processing_depth_ > 0; } 927 928 // If an object has an AllocationMemento trailing it, return it, otherwise 929 // return NULL; 930 inline AllocationMemento* FindAllocationMemento(HeapObject* object); 931 932 // Returns false if not able to reserve. 933 bool ReserveSpace(Reservation* reservations); 934 935 // 936 // Support for the API. 937 // 938 939 void CreateApiObjects(); 940 941 // Implements the corresponding V8 API function. 942 bool IdleNotification(double deadline_in_seconds); 943 bool IdleNotification(int idle_time_in_ms); 944 945 double MonotonicallyIncreasingTimeInMs(); 946 947 void RecordStats(HeapStats* stats, bool take_snapshot = false); 948 949 // Check new space expansion criteria and expand semispaces if it was hit. 950 void CheckNewSpaceExpansionCriteria(); 951 952 inline bool HeapIsFullEnoughToStartIncrementalMarking(intptr_t limit) { 953 if (FLAG_stress_compaction && (gc_count_ & 1) != 0) return true; 954 955 intptr_t adjusted_allocation_limit = limit - new_space_.Capacity(); 956 957 if (PromotedTotalSize() >= adjusted_allocation_limit) return true; 958 959 return false; 960 } 961 962 void VisitExternalResources(v8::ExternalResourceVisitor* visitor); 963 964 // An object should be promoted if the object has survived a 965 // scavenge operation. 966 inline bool ShouldBePromoted(Address old_address, int object_size); 967 968 void ClearNormalizedMapCaches(); 969 970 void IncrementDeferredCount(v8::Isolate::UseCounterFeature feature); 971 972 inline bool OldGenerationAllocationLimitReached(); 973 974 void QueueMemoryChunkForFree(MemoryChunk* chunk); 975 void FilterStoreBufferEntriesOnAboutToBeFreedPages(); 976 void FreeQueuedChunks(MemoryChunk* list_head); 977 void FreeQueuedChunks(); 978 void WaitUntilUnmappingOfFreeChunksCompleted(); 979 980 // Completely clear the Instanceof cache (to stop it keeping objects alive 981 // around a GC). 982 inline void CompletelyClearInstanceofCache(); 983 984 inline uint32_t HashSeed(); 985 986 inline int NextScriptId(); 987 988 inline void SetArgumentsAdaptorDeoptPCOffset(int pc_offset); 989 inline void SetConstructStubDeoptPCOffset(int pc_offset); 990 inline void SetGetterStubDeoptPCOffset(int pc_offset); 991 inline void SetSetterStubDeoptPCOffset(int pc_offset); 992 993 // For post mortem debugging. 994 void RememberUnmappedPage(Address page, bool compacted); 995 996 // Global inline caching age: it is incremented on some GCs after context 997 // disposal. We use it to flush inline caches. 998 int global_ic_age() { return global_ic_age_; } 999 1000 void AgeInlineCaches() { 1001 global_ic_age_ = (global_ic_age_ + 1) & SharedFunctionInfo::ICAgeBits::kMax; 1002 } 1003 1004 int64_t amount_of_external_allocated_memory() { 1005 return amount_of_external_allocated_memory_; 1006 } 1007 1008 void update_amount_of_external_allocated_memory(int64_t delta) { 1009 amount_of_external_allocated_memory_ += delta; 1010 } 1011 1012 void DeoptMarkedAllocationSites(); 1013 1014 bool DeoptMaybeTenuredAllocationSites() { 1015 return new_space_.IsAtMaximumCapacity() && maximum_size_scavenges_ == 0; 1016 } 1017 1018 void AddWeakObjectToCodeDependency(Handle<HeapObject> obj, 1019 Handle<DependentCode> dep); 1020 1021 DependentCode* LookupWeakObjectToCodeDependency(Handle<HeapObject> obj); 1022 1023 void AddRetainedMap(Handle<Map> map); 1024 1025 // This event is triggered after successful allocation of a new object made 1026 // by runtime. Allocations of target space for object evacuation do not 1027 // trigger the event. In order to track ALL allocations one must turn off 1028 // FLAG_inline_new and FLAG_use_allocation_folding. 1029 inline void OnAllocationEvent(HeapObject* object, int size_in_bytes); 1030 1031 // This event is triggered after object is moved to a new place. 1032 inline void OnMoveEvent(HeapObject* target, HeapObject* source, 1033 int size_in_bytes); 1034 1035 bool deserialization_complete() const { return deserialization_complete_; } 1036 1037 bool HasLowAllocationRate(); 1038 bool HasHighFragmentation(); 1039 bool HasHighFragmentation(intptr_t used, intptr_t committed); 1040 1041 void SetOptimizeForLatency() { optimize_for_memory_usage_ = false; } 1042 void SetOptimizeForMemoryUsage() { optimize_for_memory_usage_ = true; } 1043 bool ShouldOptimizeForMemoryUsage() { return optimize_for_memory_usage_; } 1044 1045 // =========================================================================== 1046 // Initialization. =========================================================== 1047 // =========================================================================== 1048 1049 // Configure heap size in MB before setup. Return false if the heap has been 1050 // set up already. 1051 bool ConfigureHeap(int max_semi_space_size, int max_old_space_size, 1052 int max_executable_size, size_t code_range_size); 1053 bool ConfigureHeapDefault(); 1054 1055 // Prepares the heap, setting up memory areas that are needed in the isolate 1056 // without actually creating any objects. 1057 bool SetUp(); 1058 1059 // Bootstraps the object heap with the core set of objects required to run. 1060 // Returns whether it succeeded. 1061 bool CreateHeapObjects(); 1062 1063 // Destroys all memory allocated by the heap. 1064 void TearDown(); 1065 1066 // Returns whether SetUp has been called. 1067 bool HasBeenSetUp(); 1068 1069 // =========================================================================== 1070 // Getters for spaces. ======================================================= 1071 // =========================================================================== 1072 1073 // Return the starting address and a mask for the new space. And-masking an 1074 // address with the mask will result in the start address of the new space 1075 // for all addresses in either semispace. 1076 Address NewSpaceStart() { return new_space_.start(); } 1077 uintptr_t NewSpaceMask() { return new_space_.mask(); } 1078 Address NewSpaceTop() { return new_space_.top(); } 1079 1080 NewSpace* new_space() { return &new_space_; } 1081 OldSpace* old_space() { return old_space_; } 1082 OldSpace* code_space() { return code_space_; } 1083 MapSpace* map_space() { return map_space_; } 1084 LargeObjectSpace* lo_space() { return lo_space_; } 1085 1086 PagedSpace* paged_space(int idx) { 1087 switch (idx) { 1088 case OLD_SPACE: 1089 return old_space(); 1090 case MAP_SPACE: 1091 return map_space(); 1092 case CODE_SPACE: 1093 return code_space(); 1094 case NEW_SPACE: 1095 case LO_SPACE: 1096 UNREACHABLE(); 1097 } 1098 return NULL; 1099 } 1100 1101 Space* space(int idx) { 1102 switch (idx) { 1103 case NEW_SPACE: 1104 return new_space(); 1105 case LO_SPACE: 1106 return lo_space(); 1107 default: 1108 return paged_space(idx); 1109 } 1110 } 1111 1112 // Returns name of the space. 1113 const char* GetSpaceName(int idx); 1114 1115 // =========================================================================== 1116 // Getters to other components. ============================================== 1117 // =========================================================================== 1118 1119 GCTracer* tracer() { return tracer_; } 1120 1121 PromotionQueue* promotion_queue() { return &promotion_queue_; } 1122 1123 inline Isolate* isolate(); 1124 1125 MarkCompactCollector* mark_compact_collector() { 1126 return mark_compact_collector_; 1127 } 1128 1129 // =========================================================================== 1130 // Root set access. ========================================================== 1131 // =========================================================================== 1132 1133 // Heap root getters. 1134 #define ROOT_ACCESSOR(type, name, camel_name) inline type* name(); 1135 ROOT_LIST(ROOT_ACCESSOR) 1136 #undef ROOT_ACCESSOR 1137 1138 // Utility type maps. 1139 #define STRUCT_MAP_ACCESSOR(NAME, Name, name) inline Map* name##_map(); 1140 STRUCT_LIST(STRUCT_MAP_ACCESSOR) 1141 #undef STRUCT_MAP_ACCESSOR 1142 1143 #define STRING_ACCESSOR(name, str) inline String* name(); 1144 INTERNALIZED_STRING_LIST(STRING_ACCESSOR) 1145 #undef STRING_ACCESSOR 1146 1147 #define SYMBOL_ACCESSOR(name) inline Symbol* name(); 1148 PRIVATE_SYMBOL_LIST(SYMBOL_ACCESSOR) 1149 #undef SYMBOL_ACCESSOR 1150 1151 #define SYMBOL_ACCESSOR(name, description) inline Symbol* name(); 1152 PUBLIC_SYMBOL_LIST(SYMBOL_ACCESSOR) 1153 WELL_KNOWN_SYMBOL_LIST(SYMBOL_ACCESSOR) 1154 #undef SYMBOL_ACCESSOR 1155 1156 Object* root(RootListIndex index) { return roots_[index]; } 1157 Handle<Object> root_handle(RootListIndex index) { 1158 return Handle<Object>(&roots_[index]); 1159 } 1160 1161 // Generated code can embed this address to get access to the roots. 1162 Object** roots_array_start() { return roots_; } 1163 1164 // Sets the stub_cache_ (only used when expanding the dictionary). 1165 void SetRootCodeStubs(UnseededNumberDictionary* value) { 1166 roots_[kCodeStubsRootIndex] = value; 1167 } 1168 1169 // Sets the non_monomorphic_cache_ (only used when expanding the dictionary). 1170 void SetRootNonMonomorphicCache(UnseededNumberDictionary* value) { 1171 roots_[kNonMonomorphicCacheRootIndex] = value; 1172 } 1173 1174 void SetRootMaterializedObjects(FixedArray* objects) { 1175 roots_[kMaterializedObjectsRootIndex] = objects; 1176 } 1177 1178 void SetRootScriptList(Object* value) { 1179 roots_[kScriptListRootIndex] = value; 1180 } 1181 1182 void SetRootStringTable(StringTable* value) { 1183 roots_[kStringTableRootIndex] = value; 1184 } 1185 1186 void SetRootNoScriptSharedFunctionInfos(Object* value) { 1187 roots_[kNoScriptSharedFunctionInfosRootIndex] = value; 1188 } 1189 1190 // Set the stack limit in the roots_ array. Some architectures generate 1191 // code that looks here, because it is faster than loading from the static 1192 // jslimit_/real_jslimit_ variable in the StackGuard. 1193 void SetStackLimits(); 1194 1195 // Generated code can treat direct references to this root as constant. 1196 bool RootCanBeTreatedAsConstant(RootListIndex root_index); 1197 1198 Map* MapForFixedTypedArray(ExternalArrayType array_type); 1199 RootListIndex RootIndexForFixedTypedArray(ExternalArrayType array_type); 1200 1201 RootListIndex RootIndexForEmptyFixedTypedArray(ElementsKind kind); 1202 FixedTypedArrayBase* EmptyFixedTypedArrayForMap(Map* map); 1203 1204 void RegisterStrongRoots(Object** start, Object** end); 1205 void UnregisterStrongRoots(Object** start); 1206 1207 // =========================================================================== 1208 // Inline allocation. ======================================================== 1209 // =========================================================================== 1210 1211 // Indicates whether inline bump-pointer allocation has been disabled. 1212 bool inline_allocation_disabled() { return inline_allocation_disabled_; } 1213 1214 // Switch whether inline bump-pointer allocation should be used. 1215 void EnableInlineAllocation(); 1216 void DisableInlineAllocation(); 1217 1218 // =========================================================================== 1219 // Methods triggering GCs. =================================================== 1220 // =========================================================================== 1221 1222 // Performs garbage collection operation. 1223 // Returns whether there is a chance that another major GC could 1224 // collect more garbage. 1225 inline bool CollectGarbage( 1226 AllocationSpace space, const char* gc_reason = NULL, 1227 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags); 1228 1229 // Performs a full garbage collection. If (flags & kMakeHeapIterableMask) is 1230 // non-zero, then the slower precise sweeper is used, which leaves the heap 1231 // in a state where we can iterate over the heap visiting all objects. 1232 void CollectAllGarbage( 1233 int flags = kFinalizeIncrementalMarkingMask, const char* gc_reason = NULL, 1234 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags); 1235 1236 // Last hope GC, should try to squeeze as much as possible. 1237 void CollectAllAvailableGarbage(const char* gc_reason = NULL); 1238 1239 // Reports and external memory pressure event, either performs a major GC or 1240 // completes incremental marking in order to free external resources. 1241 void ReportExternalMemoryPressure(const char* gc_reason = NULL); 1242 1243 // Invoked when GC was requested via the stack guard. 1244 void HandleGCRequest(); 1245 1246 // =========================================================================== 1247 // Iterators. ================================================================ 1248 // =========================================================================== 1249 1250 // Iterates over all roots in the heap. 1251 void IterateRoots(ObjectVisitor* v, VisitMode mode); 1252 // Iterates over all strong roots in the heap. 1253 void IterateStrongRoots(ObjectVisitor* v, VisitMode mode); 1254 // Iterates over entries in the smi roots list. Only interesting to the 1255 // serializer/deserializer, since GC does not care about smis. 1256 void IterateSmiRoots(ObjectVisitor* v); 1257 // Iterates over all the other roots in the heap. 1258 void IterateWeakRoots(ObjectVisitor* v, VisitMode mode); 1259 1260 // Iterate pointers to from semispace of new space found in memory interval 1261 // from start to end within |object|. 1262 void IteratePointersToFromSpace(HeapObject* target, int size, 1263 ObjectSlotCallback callback); 1264 1265 void IterateAndMarkPointersToFromSpace(HeapObject* object, Address start, 1266 Address end, bool record_slots, 1267 ObjectSlotCallback callback); 1268 1269 // =========================================================================== 1270 // Store buffer API. ========================================================= 1271 // =========================================================================== 1272 1273 // Write barrier support for address[offset] = o. 1274 INLINE(void RecordWrite(Address address, int offset)); 1275 1276 // Write barrier support for address[start : start + len[ = o. 1277 INLINE(void RecordWrites(Address address, int start, int len)); 1278 1279 Address* store_buffer_top_address() { 1280 return reinterpret_cast<Address*>(&roots_[kStoreBufferTopRootIndex]); 1281 } 1282 1283 // =========================================================================== 1284 // Incremental marking API. ================================================== 1285 // =========================================================================== 1286 1287 // Start incremental marking and ensure that idle time handler can perform 1288 // incremental steps. 1289 void StartIdleIncrementalMarking(); 1290 1291 // Starts incremental marking assuming incremental marking is currently 1292 // stopped. 1293 void StartIncrementalMarking(int gc_flags = kNoGCFlags, 1294 const GCCallbackFlags gc_callback_flags = 1295 GCCallbackFlags::kNoGCCallbackFlags, 1296 const char* reason = nullptr); 1297 1298 void FinalizeIncrementalMarkingIfComplete(const char* comment); 1299 1300 bool TryFinalizeIdleIncrementalMarking(double idle_time_in_ms); 1301 1302 IncrementalMarking* incremental_marking() { return incremental_marking_; } 1303 1304 // =========================================================================== 1305 // External string table API. ================================================ 1306 // =========================================================================== 1307 1308 // Registers an external string. 1309 inline void RegisterExternalString(String* string); 1310 1311 // Finalizes an external string by deleting the associated external 1312 // data and clearing the resource pointer. 1313 inline void FinalizeExternalString(String* string); 1314 1315 // =========================================================================== 1316 // Methods checking/returning the space of a given object/address. =========== 1317 // =========================================================================== 1318 1319 // Returns whether the object resides in new space. 1320 inline bool InNewSpace(Object* object); 1321 inline bool InNewSpace(Address address); 1322 inline bool InNewSpacePage(Address address); 1323 inline bool InFromSpace(Object* object); 1324 inline bool InToSpace(Object* object); 1325 1326 // Returns whether the object resides in old space. 1327 inline bool InOldSpace(Address address); 1328 inline bool InOldSpace(Object* object); 1329 1330 // Checks whether an address/object in the heap (including auxiliary 1331 // area and unused area). 1332 bool Contains(Address addr); 1333 bool Contains(HeapObject* value); 1334 1335 // Checks whether an address/object in a space. 1336 // Currently used by tests, serialization and heap verification only. 1337 bool InSpace(Address addr, AllocationSpace space); 1338 bool InSpace(HeapObject* value, AllocationSpace space); 1339 1340 // =========================================================================== 1341 // Object statistics tracking. =============================================== 1342 // =========================================================================== 1343 1344 // Returns the number of buckets used by object statistics tracking during a 1345 // major GC. Note that the following methods fail gracefully when the bounds 1346 // are exceeded though. 1347 size_t NumberOfTrackedHeapObjectTypes(); 1348 1349 // Returns object statistics about count and size at the last major GC. 1350 // Objects are being grouped into buckets that roughly resemble existing 1351 // instance types. 1352 size_t ObjectCountAtLastGC(size_t index); 1353 size_t ObjectSizeAtLastGC(size_t index); 1354 1355 // Retrieves names of buckets used by object statistics tracking. 1356 bool GetObjectTypeName(size_t index, const char** object_type, 1357 const char** object_sub_type); 1358 1359 // =========================================================================== 1360 // GC statistics. ============================================================ 1361 // =========================================================================== 1362 1363 // Returns the maximum amount of memory reserved for the heap. For 1364 // the young generation, we reserve 4 times the amount needed for a 1365 // semi space. The young generation consists of two semi spaces and 1366 // we reserve twice the amount needed for those in order to ensure 1367 // that new space can be aligned to its size. 1368 intptr_t MaxReserved() { 1369 return 4 * reserved_semispace_size_ + max_old_generation_size_; 1370 } 1371 int MaxSemiSpaceSize() { return max_semi_space_size_; } 1372 int ReservedSemiSpaceSize() { return reserved_semispace_size_; } 1373 int InitialSemiSpaceSize() { return initial_semispace_size_; } 1374 int TargetSemiSpaceSize() { return target_semispace_size_; } 1375 intptr_t MaxOldGenerationSize() { return max_old_generation_size_; } 1376 intptr_t MaxExecutableSize() { return max_executable_size_; } 1377 1378 // Returns the capacity of the heap in bytes w/o growing. Heap grows when 1379 // more spaces are needed until it reaches the limit. 1380 intptr_t Capacity(); 1381 1382 // Returns the amount of memory currently committed for the heap. 1383 intptr_t CommittedMemory(); 1384 1385 // Returns the amount of memory currently committed for the old space. 1386 intptr_t CommittedOldGenerationMemory(); 1387 1388 // Returns the amount of executable memory currently committed for the heap. 1389 intptr_t CommittedMemoryExecutable(); 1390 1391 // Returns the amount of phyical memory currently committed for the heap. 1392 size_t CommittedPhysicalMemory(); 1393 1394 // Returns the maximum amount of memory ever committed for the heap. 1395 intptr_t MaximumCommittedMemory() { return maximum_committed_; } 1396 1397 // Updates the maximum committed memory for the heap. Should be called 1398 // whenever a space grows. 1399 void UpdateMaximumCommitted(); 1400 1401 // Returns the available bytes in space w/o growing. 1402 // Heap doesn't guarantee that it can allocate an object that requires 1403 // all available bytes. Check MaxHeapObjectSize() instead. 1404 intptr_t Available(); 1405 1406 // Returns of size of all objects residing in the heap. 1407 intptr_t SizeOfObjects(); 1408 1409 void UpdateSurvivalStatistics(int start_new_space_size); 1410 1411 inline void IncrementPromotedObjectsSize(int object_size) { 1412 DCHECK_GE(object_size, 0); 1413 promoted_objects_size_ += object_size; 1414 } 1415 inline intptr_t promoted_objects_size() { return promoted_objects_size_; } 1416 1417 inline void IncrementSemiSpaceCopiedObjectSize(int object_size) { 1418 DCHECK_GE(object_size, 0); 1419 semi_space_copied_object_size_ += object_size; 1420 } 1421 inline intptr_t semi_space_copied_object_size() { 1422 return semi_space_copied_object_size_; 1423 } 1424 1425 inline intptr_t SurvivedNewSpaceObjectSize() { 1426 return promoted_objects_size_ + semi_space_copied_object_size_; 1427 } 1428 1429 inline void IncrementNodesDiedInNewSpace() { nodes_died_in_new_space_++; } 1430 1431 inline void IncrementNodesCopiedInNewSpace() { nodes_copied_in_new_space_++; } 1432 1433 inline void IncrementNodesPromoted() { nodes_promoted_++; } 1434 1435 inline void IncrementYoungSurvivorsCounter(int survived) { 1436 DCHECK(survived >= 0); 1437 survived_last_scavenge_ = survived; 1438 survived_since_last_expansion_ += survived; 1439 } 1440 1441 inline intptr_t PromotedTotalSize() { 1442 int64_t total = PromotedSpaceSizeOfObjects() + PromotedExternalMemorySize(); 1443 if (total > std::numeric_limits<intptr_t>::max()) { 1444 // TODO(erikcorry): Use uintptr_t everywhere we do heap size calculations. 1445 return std::numeric_limits<intptr_t>::max(); 1446 } 1447 if (total < 0) return 0; 1448 return static_cast<intptr_t>(total); 1449 } 1450 1451 void UpdateNewSpaceAllocationCounter() { 1452 new_space_allocation_counter_ = NewSpaceAllocationCounter(); 1453 } 1454 1455 size_t NewSpaceAllocationCounter() { 1456 return new_space_allocation_counter_ + new_space()->AllocatedSinceLastGC(); 1457 } 1458 1459 // This should be used only for testing. 1460 void set_new_space_allocation_counter(size_t new_value) { 1461 new_space_allocation_counter_ = new_value; 1462 } 1463 1464 void UpdateOldGenerationAllocationCounter() { 1465 old_generation_allocation_counter_ = OldGenerationAllocationCounter(); 1466 } 1467 1468 size_t OldGenerationAllocationCounter() { 1469 return old_generation_allocation_counter_ + PromotedSinceLastGC(); 1470 } 1471 1472 // This should be used only for testing. 1473 void set_old_generation_allocation_counter(size_t new_value) { 1474 old_generation_allocation_counter_ = new_value; 1475 } 1476 1477 size_t PromotedSinceLastGC() { 1478 return PromotedSpaceSizeOfObjects() - old_generation_size_at_last_gc_; 1479 } 1480 1481 int gc_count() const { return gc_count_; } 1482 1483 // Returns the size of objects residing in non new spaces. 1484 intptr_t PromotedSpaceSizeOfObjects(); 1485 1486 double total_regexp_code_generated() { return total_regexp_code_generated_; } 1487 void IncreaseTotalRegexpCodeGenerated(int size) { 1488 total_regexp_code_generated_ += size; 1489 } 1490 1491 void IncrementCodeGeneratedBytes(bool is_crankshafted, int size) { 1492 if (is_crankshafted) { 1493 crankshaft_codegen_bytes_generated_ += size; 1494 } else { 1495 full_codegen_bytes_generated_ += size; 1496 } 1497 } 1498 1499 // =========================================================================== 1500 // Prologue/epilogue callback methods.======================================== 1501 // =========================================================================== 1502 1503 void AddGCPrologueCallback(v8::Isolate::GCCallback callback, 1504 GCType gc_type_filter, bool pass_isolate = true); 1505 void RemoveGCPrologueCallback(v8::Isolate::GCCallback callback); 1506 1507 void AddGCEpilogueCallback(v8::Isolate::GCCallback callback, 1508 GCType gc_type_filter, bool pass_isolate = true); 1509 void RemoveGCEpilogueCallback(v8::Isolate::GCCallback callback); 1510 1511 void CallGCPrologueCallbacks(GCType gc_type, GCCallbackFlags flags); 1512 void CallGCEpilogueCallbacks(GCType gc_type, GCCallbackFlags flags); 1513 1514 // =========================================================================== 1515 // Allocation methods. ======================================================= 1516 // =========================================================================== 1517 1518 // Creates a filler object and returns a heap object immediately after it. 1519 MUST_USE_RESULT HeapObject* PrecedeWithFiller(HeapObject* object, 1520 int filler_size); 1521 1522 // Creates a filler object if needed for alignment and returns a heap object 1523 // immediately after it. If any space is left after the returned object, 1524 // another filler object is created so the over allocated memory is iterable. 1525 MUST_USE_RESULT HeapObject* AlignWithFiller(HeapObject* object, 1526 int object_size, 1527 int allocation_size, 1528 AllocationAlignment alignment); 1529 1530 // =========================================================================== 1531 // ArrayBuffer tracking. ===================================================== 1532 // =========================================================================== 1533 1534 void RegisterNewArrayBuffer(JSArrayBuffer* buffer); 1535 void UnregisterArrayBuffer(JSArrayBuffer* buffer); 1536 1537 inline ArrayBufferTracker* array_buffer_tracker() { 1538 return array_buffer_tracker_; 1539 } 1540 1541 // =========================================================================== 1542 // Allocation site tracking. ================================================= 1543 // =========================================================================== 1544 1545 // Updates the AllocationSite of a given {object}. If the global prenuring 1546 // storage is passed as {pretenuring_feedback} the memento found count on 1547 // the corresponding allocation site is immediately updated and an entry 1548 // in the hash map is created. Otherwise the entry (including a the count 1549 // value) is cached on the local pretenuring feedback. 1550 inline void UpdateAllocationSite(HeapObject* object, 1551 HashMap* pretenuring_feedback); 1552 1553 // Removes an entry from the global pretenuring storage. 1554 inline void RemoveAllocationSitePretenuringFeedback(AllocationSite* site); 1555 1556 // Merges local pretenuring feedback into the global one. Note that this 1557 // method needs to be called after evacuation, as allocation sites may be 1558 // evacuated and this method resolves forward pointers accordingly. 1559 void MergeAllocationSitePretenuringFeedback( 1560 const HashMap& local_pretenuring_feedback); 1561 1562 // ============================================================================= 1563 1564 #ifdef VERIFY_HEAP 1565 // Verify the heap is in its normal state before or after a GC. 1566 void Verify(); 1567 #endif 1568 1569 #ifdef DEBUG 1570 void set_allocation_timeout(int timeout) { allocation_timeout_ = timeout; } 1571 1572 void TracePathToObjectFrom(Object* target, Object* root); 1573 void TracePathToObject(Object* target); 1574 void TracePathToGlobal(); 1575 1576 void Print(); 1577 void PrintHandles(); 1578 1579 // Report heap statistics. 1580 void ReportHeapStatistics(const char* title); 1581 void ReportCodeStatistics(const char* title); 1582 #endif 1583 1584 private: 1585 class PretenuringScope; 1586 class UnmapFreeMemoryTask; 1587 1588 // External strings table is a place where all external strings are 1589 // registered. We need to keep track of such strings to properly 1590 // finalize them. 1591 class ExternalStringTable { 1592 public: 1593 // Registers an external string. 1594 inline void AddString(String* string); 1595 1596 inline void Iterate(ObjectVisitor* v); 1597 1598 // Restores internal invariant and gets rid of collected strings. 1599 // Must be called after each Iterate() that modified the strings. 1600 void CleanUp(); 1601 1602 // Destroys all allocated memory. 1603 void TearDown(); 1604 1605 private: 1606 explicit ExternalStringTable(Heap* heap) : heap_(heap) {} 1607 1608 inline void Verify(); 1609 1610 inline void AddOldString(String* string); 1611 1612 // Notifies the table that only a prefix of the new list is valid. 1613 inline void ShrinkNewStrings(int position); 1614 1615 // To speed up scavenge collections new space string are kept 1616 // separate from old space strings. 1617 List<Object*> new_space_strings_; 1618 List<Object*> old_space_strings_; 1619 1620 Heap* heap_; 1621 1622 friend class Heap; 1623 1624 DISALLOW_COPY_AND_ASSIGN(ExternalStringTable); 1625 }; 1626 1627 struct StrongRootsList; 1628 1629 struct StringTypeTable { 1630 InstanceType type; 1631 int size; 1632 RootListIndex index; 1633 }; 1634 1635 struct ConstantStringTable { 1636 const char* contents; 1637 RootListIndex index; 1638 }; 1639 1640 struct StructTable { 1641 InstanceType type; 1642 int size; 1643 RootListIndex index; 1644 }; 1645 1646 struct GCCallbackPair { 1647 GCCallbackPair(v8::Isolate::GCCallback callback, GCType gc_type, 1648 bool pass_isolate) 1649 : callback(callback), gc_type(gc_type), pass_isolate(pass_isolate) {} 1650 1651 bool operator==(const GCCallbackPair& other) const { 1652 return other.callback == callback; 1653 } 1654 1655 v8::Isolate::GCCallback callback; 1656 GCType gc_type; 1657 bool pass_isolate; 1658 }; 1659 1660 typedef String* (*ExternalStringTableUpdaterCallback)(Heap* heap, 1661 Object** pointer); 1662 1663 static const int kInitialStringTableSize = 2048; 1664 static const int kInitialEvalCacheSize = 64; 1665 static const int kInitialNumberStringCacheSize = 256; 1666 1667 static const int kRememberedUnmappedPages = 128; 1668 1669 static const StringTypeTable string_type_table[]; 1670 static const ConstantStringTable constant_string_table[]; 1671 static const StructTable struct_table[]; 1672 1673 static const int kYoungSurvivalRateHighThreshold = 90; 1674 static const int kYoungSurvivalRateAllowedDeviation = 15; 1675 static const int kOldSurvivalRateLowThreshold = 10; 1676 1677 static const int kMaxMarkCompactsInIdleRound = 7; 1678 static const int kIdleScavengeThreshold = 5; 1679 1680 static const int kInitialFeedbackCapacity = 256; 1681 1682 Heap(); 1683 1684 static String* UpdateNewSpaceReferenceInExternalStringTableEntry( 1685 Heap* heap, Object** pointer); 1686 1687 static void ScavengeStoreBufferCallback(Heap* heap, MemoryChunk* page, 1688 StoreBufferEvent event); 1689 1690 // Selects the proper allocation space based on the pretenuring decision. 1691 static AllocationSpace SelectSpace(PretenureFlag pretenure) { 1692 return (pretenure == TENURED) ? OLD_SPACE : NEW_SPACE; 1693 } 1694 1695 #define ROOT_ACCESSOR(type, name, camel_name) \ 1696 inline void set_##name(type* value); 1697 ROOT_LIST(ROOT_ACCESSOR) 1698 #undef ROOT_ACCESSOR 1699 1700 StoreBuffer* store_buffer() { return &store_buffer_; } 1701 1702 void set_current_gc_flags(int flags) { 1703 current_gc_flags_ = flags; 1704 DCHECK(!ShouldFinalizeIncrementalMarking() || 1705 !ShouldAbortIncrementalMarking()); 1706 } 1707 1708 inline bool ShouldReduceMemory() const { 1709 return current_gc_flags_ & kReduceMemoryFootprintMask; 1710 } 1711 1712 inline bool ShouldAbortIncrementalMarking() const { 1713 return current_gc_flags_ & kAbortIncrementalMarkingMask; 1714 } 1715 1716 inline bool ShouldFinalizeIncrementalMarking() const { 1717 return current_gc_flags_ & kFinalizeIncrementalMarkingMask; 1718 } 1719 1720 void PreprocessStackTraces(); 1721 1722 // Checks whether a global GC is necessary 1723 GarbageCollector SelectGarbageCollector(AllocationSpace space, 1724 const char** reason); 1725 1726 // Make sure there is a filler value behind the top of the new space 1727 // so that the GC does not confuse some unintialized/stale memory 1728 // with the allocation memento of the object at the top 1729 void EnsureFillerObjectAtTop(); 1730 1731 // Ensure that we have swept all spaces in such a way that we can iterate 1732 // over all objects. May cause a GC. 1733 void MakeHeapIterable(); 1734 1735 // Performs garbage collection operation. 1736 // Returns whether there is a chance that another major GC could 1737 // collect more garbage. 1738 bool CollectGarbage( 1739 GarbageCollector collector, const char* gc_reason, 1740 const char* collector_reason, 1741 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags); 1742 1743 // Performs garbage collection 1744 // Returns whether there is a chance another major GC could 1745 // collect more garbage. 1746 bool PerformGarbageCollection( 1747 GarbageCollector collector, 1748 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags); 1749 1750 inline void UpdateOldSpaceLimits(); 1751 1752 // Initializes a JSObject based on its map. 1753 void InitializeJSObjectFromMap(JSObject* obj, FixedArray* properties, 1754 Map* map); 1755 1756 // Initializes JSObject body starting at given offset. 1757 void InitializeJSObjectBody(JSObject* obj, Map* map, int start_offset); 1758 1759 void InitializeAllocationMemento(AllocationMemento* memento, 1760 AllocationSite* allocation_site); 1761 1762 bool CreateInitialMaps(); 1763 void CreateInitialObjects(); 1764 1765 // These five Create*EntryStub functions are here and forced to not be inlined 1766 // because of a gcc-4.4 bug that assigns wrong vtable entries. 1767 NO_INLINE(void CreateJSEntryStub()); 1768 NO_INLINE(void CreateJSConstructEntryStub()); 1769 1770 void CreateFixedStubs(); 1771 1772 HeapObject* DoubleAlignForDeserialization(HeapObject* object, int size); 1773 1774 // Commits from space if it is uncommitted. 1775 void EnsureFromSpaceIsCommitted(); 1776 1777 // Uncommit unused semi space. 1778 bool UncommitFromSpace() { return new_space_.UncommitFromSpace(); } 1779 1780 // Fill in bogus values in from space 1781 void ZapFromSpace(); 1782 1783 // Deopts all code that contains allocation instruction which are tenured or 1784 // not tenured. Moreover it clears the pretenuring allocation site statistics. 1785 void ResetAllAllocationSitesDependentCode(PretenureFlag flag); 1786 1787 // Evaluates local pretenuring for the old space and calls 1788 // ResetAllTenuredAllocationSitesDependentCode if too many objects died in 1789 // the old space. 1790 void EvaluateOldSpaceLocalPretenuring(uint64_t size_of_objects_before_gc); 1791 1792 // Record statistics before and after garbage collection. 1793 void ReportStatisticsBeforeGC(); 1794 void ReportStatisticsAfterGC(); 1795 1796 // Creates and installs the full-sized number string cache. 1797 int FullSizeNumberStringCacheLength(); 1798 // Flush the number to string cache. 1799 void FlushNumberStringCache(); 1800 1801 // TODO(hpayer): Allocation site pretenuring may make this method obsolete. 1802 // Re-visit incremental marking heuristics. 1803 bool IsHighSurvivalRate() { return high_survival_rate_period_length_ > 0; } 1804 1805 void ConfigureInitialOldGenerationSize(); 1806 1807 bool HasLowYoungGenerationAllocationRate(); 1808 bool HasLowOldGenerationAllocationRate(); 1809 double YoungGenerationMutatorUtilization(); 1810 double OldGenerationMutatorUtilization(); 1811 1812 void ReduceNewSpaceSize(); 1813 1814 bool TryFinalizeIdleIncrementalMarking( 1815 double idle_time_in_ms, size_t size_of_objects, 1816 size_t mark_compact_speed_in_bytes_per_ms); 1817 1818 GCIdleTimeHeapState ComputeHeapState(); 1819 1820 bool PerformIdleTimeAction(GCIdleTimeAction action, 1821 GCIdleTimeHeapState heap_state, 1822 double deadline_in_ms); 1823 1824 void IdleNotificationEpilogue(GCIdleTimeAction action, 1825 GCIdleTimeHeapState heap_state, double start_ms, 1826 double deadline_in_ms); 1827 1828 inline void UpdateAllocationsHash(HeapObject* object); 1829 inline void UpdateAllocationsHash(uint32_t value); 1830 void PrintAlloctionsHash(); 1831 1832 void AddToRingBuffer(const char* string); 1833 void GetFromRingBuffer(char* buffer); 1834 1835 void CompactRetainedMaps(ArrayList* retained_maps); 1836 1837 // Attempt to over-approximate the weak closure by marking object groups and 1838 // implicit references from global handles, but don't atomically complete 1839 // marking. If we continue to mark incrementally, we might have marked 1840 // objects that die later. 1841 void FinalizeIncrementalMarking(const char* gc_reason); 1842 1843 // Returns the timer used for a given GC type. 1844 // - GCScavenger: young generation GC 1845 // - GCCompactor: full GC 1846 // - GCFinalzeMC: finalization of incremental full GC 1847 // - GCFinalizeMCReduceMemory: finalization of incremental full GC with 1848 // memory reduction 1849 HistogramTimer* GCTypeTimer(GarbageCollector collector); 1850 1851 // =========================================================================== 1852 // Pretenuring. ============================================================== 1853 // =========================================================================== 1854 1855 // Pretenuring decisions are made based on feedback collected during new space 1856 // evacuation. Note that between feedback collection and calling this method 1857 // object in old space must not move. 1858 void ProcessPretenuringFeedback(); 1859 1860 // =========================================================================== 1861 // Actual GC. ================================================================ 1862 // =========================================================================== 1863 1864 // Code that should be run before and after each GC. Includes some 1865 // reporting/verification activities when compiled with DEBUG set. 1866 void GarbageCollectionPrologue(); 1867 void GarbageCollectionEpilogue(); 1868 1869 // Performs a major collection in the whole heap. 1870 void MarkCompact(); 1871 1872 // Code to be run before and after mark-compact. 1873 void MarkCompactPrologue(); 1874 void MarkCompactEpilogue(); 1875 1876 // Performs a minor collection in new generation. 1877 void Scavenge(); 1878 1879 Address DoScavenge(ObjectVisitor* scavenge_visitor, Address new_space_front); 1880 1881 void UpdateNewSpaceReferencesInExternalStringTable( 1882 ExternalStringTableUpdaterCallback updater_func); 1883 1884 void UpdateReferencesInExternalStringTable( 1885 ExternalStringTableUpdaterCallback updater_func); 1886 1887 void ProcessAllWeakReferences(WeakObjectRetainer* retainer); 1888 void ProcessYoungWeakReferences(WeakObjectRetainer* retainer); 1889 void ProcessNativeContexts(WeakObjectRetainer* retainer); 1890 void ProcessAllocationSites(WeakObjectRetainer* retainer); 1891 1892 // =========================================================================== 1893 // GC statistics. ============================================================ 1894 // =========================================================================== 1895 1896 inline intptr_t OldGenerationSpaceAvailable() { 1897 return old_generation_allocation_limit_ - PromotedTotalSize(); 1898 } 1899 1900 // Returns maximum GC pause. 1901 double get_max_gc_pause() { return max_gc_pause_; } 1902 1903 // Returns maximum size of objects alive after GC. 1904 intptr_t get_max_alive_after_gc() { return max_alive_after_gc_; } 1905 1906 // Returns minimal interval between two subsequent collections. 1907 double get_min_in_mutator() { return min_in_mutator_; } 1908 1909 // Update GC statistics that are tracked on the Heap. 1910 void UpdateCumulativeGCStatistics(double duration, double spent_in_mutator, 1911 double marking_time); 1912 1913 bool MaximumSizeScavenge() { return maximum_size_scavenges_ > 0; } 1914 1915 // =========================================================================== 1916 // Growing strategy. ========================================================= 1917 // =========================================================================== 1918 1919 // Decrease the allocation limit if the new limit based on the given 1920 // parameters is lower than the current limit. 1921 void DampenOldGenerationAllocationLimit(intptr_t old_gen_size, 1922 double gc_speed, 1923 double mutator_speed); 1924 1925 1926 // Calculates the allocation limit based on a given growing factor and a 1927 // given old generation size. 1928 intptr_t CalculateOldGenerationAllocationLimit(double factor, 1929 intptr_t old_gen_size); 1930 1931 // Sets the allocation limit to trigger the next full garbage collection. 1932 void SetOldGenerationAllocationLimit(intptr_t old_gen_size, double gc_speed, 1933 double mutator_speed); 1934 1935 // =========================================================================== 1936 // Idle notification. ======================================================== 1937 // =========================================================================== 1938 1939 bool RecentIdleNotificationHappened(); 1940 void ScheduleIdleScavengeIfNeeded(int bytes_allocated); 1941 1942 // =========================================================================== 1943 // HeapIterator helpers. ===================================================== 1944 // =========================================================================== 1945 1946 void heap_iterator_start() { heap_iterator_depth_++; } 1947 1948 void heap_iterator_end() { heap_iterator_depth_--; } 1949 1950 bool in_heap_iterator() { return heap_iterator_depth_ > 0; } 1951 1952 // =========================================================================== 1953 // Allocation methods. ======================================================= 1954 // =========================================================================== 1955 1956 // Returns a deep copy of the JavaScript object. 1957 // Properties and elements are copied too. 1958 // Optionally takes an AllocationSite to be appended in an AllocationMemento. 1959 MUST_USE_RESULT AllocationResult CopyJSObject(JSObject* source, 1960 AllocationSite* site = NULL); 1961 1962 // Allocates a JS Map in the heap. 1963 MUST_USE_RESULT AllocationResult 1964 AllocateMap(InstanceType instance_type, int instance_size, 1965 ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND); 1966 1967 // Allocates and initializes a new JavaScript object based on a 1968 // constructor. 1969 // If allocation_site is non-null, then a memento is emitted after the object 1970 // that points to the site. 1971 MUST_USE_RESULT AllocationResult AllocateJSObject( 1972 JSFunction* constructor, PretenureFlag pretenure = NOT_TENURED, 1973 AllocationSite* allocation_site = NULL); 1974 1975 // Allocates and initializes a new JavaScript object based on a map. 1976 // Passing an allocation site means that a memento will be created that 1977 // points to the site. 1978 MUST_USE_RESULT AllocationResult 1979 AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure = NOT_TENURED, 1980 AllocationSite* allocation_site = NULL); 1981 1982 // Allocates a HeapNumber from value. 1983 MUST_USE_RESULT AllocationResult 1984 AllocateHeapNumber(double value, MutableMode mode = IMMUTABLE, 1985 PretenureFlag pretenure = NOT_TENURED); 1986 1987 // Allocates SIMD values from the given lane values. 1988 #define SIMD_ALLOCATE_DECLARATION(TYPE, Type, type, lane_count, lane_type) \ 1989 AllocationResult Allocate##Type(lane_type lanes[lane_count], \ 1990 PretenureFlag pretenure = NOT_TENURED); 1991 SIMD128_TYPES(SIMD_ALLOCATE_DECLARATION) 1992 #undef SIMD_ALLOCATE_DECLARATION 1993 1994 // Allocates a byte array of the specified length 1995 MUST_USE_RESULT AllocationResult 1996 AllocateByteArray(int length, PretenureFlag pretenure = NOT_TENURED); 1997 1998 // Allocates a bytecode array with given contents. 1999 MUST_USE_RESULT AllocationResult 2000 AllocateBytecodeArray(int length, const byte* raw_bytecodes, int frame_size, 2001 int parameter_count, FixedArray* constant_pool); 2002 2003 // Copy the code and scope info part of the code object, but insert 2004 // the provided data as the relocation information. 2005 MUST_USE_RESULT AllocationResult CopyCode(Code* code, 2006 Vector<byte> reloc_info); 2007 2008 MUST_USE_RESULT AllocationResult CopyCode(Code* code); 2009 2010 // Allocates a fixed array initialized with undefined values 2011 MUST_USE_RESULT AllocationResult 2012 AllocateFixedArray(int length, PretenureFlag pretenure = NOT_TENURED); 2013 2014 // Allocate an uninitialized object. The memory is non-executable if the 2015 // hardware and OS allow. This is the single choke-point for allocations 2016 // performed by the runtime and should not be bypassed (to extend this to 2017 // inlined allocations, use the Heap::DisableInlineAllocation() support). 2018 MUST_USE_RESULT inline AllocationResult AllocateRaw( 2019 int size_in_bytes, AllocationSpace space, 2020 AllocationAlignment aligment = kWordAligned); 2021 2022 // Allocates a heap object based on the map. 2023 MUST_USE_RESULT AllocationResult 2024 Allocate(Map* map, AllocationSpace space, 2025 AllocationSite* allocation_site = NULL); 2026 2027 // Allocates a partial map for bootstrapping. 2028 MUST_USE_RESULT AllocationResult 2029 AllocatePartialMap(InstanceType instance_type, int instance_size); 2030 2031 // Allocate a block of memory in the given space (filled with a filler). 2032 // Used as a fall-back for generated code when the space is full. 2033 MUST_USE_RESULT AllocationResult 2034 AllocateFillerObject(int size, bool double_align, AllocationSpace space); 2035 2036 // Allocate an uninitialized fixed array. 2037 MUST_USE_RESULT AllocationResult 2038 AllocateRawFixedArray(int length, PretenureFlag pretenure); 2039 2040 // Allocate an uninitialized fixed double array. 2041 MUST_USE_RESULT AllocationResult 2042 AllocateRawFixedDoubleArray(int length, PretenureFlag pretenure); 2043 2044 // Allocate an initialized fixed array with the given filler value. 2045 MUST_USE_RESULT AllocationResult 2046 AllocateFixedArrayWithFiller(int length, PretenureFlag pretenure, 2047 Object* filler); 2048 2049 // Allocate and partially initializes a String. There are two String 2050 // encodings: one-byte and two-byte. These functions allocate a string of 2051 // the given length and set its map and length fields. The characters of 2052 // the string are uninitialized. 2053 MUST_USE_RESULT AllocationResult 2054 AllocateRawOneByteString(int length, PretenureFlag pretenure); 2055 MUST_USE_RESULT AllocationResult 2056 AllocateRawTwoByteString(int length, PretenureFlag pretenure); 2057 2058 // Allocates an internalized string in old space based on the character 2059 // stream. 2060 MUST_USE_RESULT inline AllocationResult AllocateInternalizedStringFromUtf8( 2061 Vector<const char> str, int chars, uint32_t hash_field); 2062 2063 MUST_USE_RESULT inline AllocationResult AllocateOneByteInternalizedString( 2064 Vector<const uint8_t> str, uint32_t hash_field); 2065 2066 MUST_USE_RESULT inline AllocationResult AllocateTwoByteInternalizedString( 2067 Vector<const uc16> str, uint32_t hash_field); 2068 2069 template <bool is_one_byte, typename T> 2070 MUST_USE_RESULT AllocationResult 2071 AllocateInternalizedStringImpl(T t, int chars, uint32_t hash_field); 2072 2073 template <typename T> 2074 MUST_USE_RESULT inline AllocationResult AllocateInternalizedStringImpl( 2075 T t, int chars, uint32_t hash_field); 2076 2077 // Allocates an uninitialized fixed array. It must be filled by the caller. 2078 MUST_USE_RESULT AllocationResult AllocateUninitializedFixedArray(int length); 2079 2080 // Make a copy of src and return it. 2081 MUST_USE_RESULT inline AllocationResult CopyFixedArray(FixedArray* src); 2082 2083 // Make a copy of src, also grow the copy, and return the copy. 2084 MUST_USE_RESULT AllocationResult 2085 CopyFixedArrayAndGrow(FixedArray* src, int grow_by, PretenureFlag pretenure); 2086 2087 // Make a copy of src, set the map, and return the copy. 2088 MUST_USE_RESULT AllocationResult 2089 CopyFixedArrayWithMap(FixedArray* src, Map* map); 2090 2091 // Make a copy of src and return it. 2092 MUST_USE_RESULT inline AllocationResult CopyFixedDoubleArray( 2093 FixedDoubleArray* src); 2094 2095 // Computes a single character string where the character has code. 2096 // A cache is used for one-byte (Latin1) codes. 2097 MUST_USE_RESULT AllocationResult 2098 LookupSingleCharacterStringFromCode(uint16_t code); 2099 2100 // Allocate a symbol in old space. 2101 MUST_USE_RESULT AllocationResult AllocateSymbol(); 2102 2103 // Allocates an external array of the specified length and type. 2104 MUST_USE_RESULT AllocationResult AllocateFixedTypedArrayWithExternalPointer( 2105 int length, ExternalArrayType array_type, void* external_pointer, 2106 PretenureFlag pretenure); 2107 2108 // Allocates a fixed typed array of the specified length and type. 2109 MUST_USE_RESULT AllocationResult 2110 AllocateFixedTypedArray(int length, ExternalArrayType array_type, 2111 bool initialize, PretenureFlag pretenure); 2112 2113 // Make a copy of src and return it. 2114 MUST_USE_RESULT AllocationResult CopyAndTenureFixedCOWArray(FixedArray* src); 2115 2116 // Make a copy of src, set the map, and return the copy. 2117 MUST_USE_RESULT AllocationResult 2118 CopyFixedDoubleArrayWithMap(FixedDoubleArray* src, Map* map); 2119 2120 // Allocates a fixed double array with uninitialized values. Returns 2121 MUST_USE_RESULT AllocationResult AllocateUninitializedFixedDoubleArray( 2122 int length, PretenureFlag pretenure = NOT_TENURED); 2123 2124 // Allocate empty fixed array. 2125 MUST_USE_RESULT AllocationResult AllocateEmptyFixedArray(); 2126 2127 // Allocate empty fixed typed array of given type. 2128 MUST_USE_RESULT AllocationResult 2129 AllocateEmptyFixedTypedArray(ExternalArrayType array_type); 2130 2131 // Allocate a tenured simple cell. 2132 MUST_USE_RESULT AllocationResult AllocateCell(Object* value); 2133 2134 // Allocate a tenured JS global property cell initialized with the hole. 2135 MUST_USE_RESULT AllocationResult AllocatePropertyCell(); 2136 2137 MUST_USE_RESULT AllocationResult AllocateWeakCell(HeapObject* value); 2138 2139 MUST_USE_RESULT AllocationResult AllocateTransitionArray(int capacity); 2140 2141 // Allocates a new utility object in the old generation. 2142 MUST_USE_RESULT AllocationResult AllocateStruct(InstanceType type); 2143 2144 // Allocates a new foreign object. 2145 MUST_USE_RESULT AllocationResult 2146 AllocateForeign(Address address, PretenureFlag pretenure = NOT_TENURED); 2147 2148 MUST_USE_RESULT AllocationResult 2149 AllocateCode(int object_size, bool immovable); 2150 2151 MUST_USE_RESULT AllocationResult InternalizeStringWithKey(HashTableKey* key); 2152 2153 MUST_USE_RESULT AllocationResult InternalizeString(String* str); 2154 2155 // =========================================================================== 2156 2157 void set_force_oom(bool value) { force_oom_ = value; } 2158 2159 // The amount of external memory registered through the API kept alive 2160 // by global handles 2161 int64_t amount_of_external_allocated_memory_; 2162 2163 // Caches the amount of external memory registered at the last global gc. 2164 int64_t amount_of_external_allocated_memory_at_last_global_gc_; 2165 2166 // This can be calculated directly from a pointer to the heap; however, it is 2167 // more expedient to get at the isolate directly from within Heap methods. 2168 Isolate* isolate_; 2169 2170 Object* roots_[kRootListLength]; 2171 2172 size_t code_range_size_; 2173 int reserved_semispace_size_; 2174 int max_semi_space_size_; 2175 int initial_semispace_size_; 2176 int target_semispace_size_; 2177 intptr_t max_old_generation_size_; 2178 intptr_t initial_old_generation_size_; 2179 bool old_generation_size_configured_; 2180 intptr_t max_executable_size_; 2181 intptr_t maximum_committed_; 2182 2183 // For keeping track of how much data has survived 2184 // scavenge since last new space expansion. 2185 int survived_since_last_expansion_; 2186 2187 // ... and since the last scavenge. 2188 int survived_last_scavenge_; 2189 2190 // This is not the depth of nested AlwaysAllocateScope's but rather a single 2191 // count, as scopes can be acquired from multiple tasks (read: threads). 2192 AtomicNumber<size_t> always_allocate_scope_count_; 2193 2194 // For keeping track of context disposals. 2195 int contexts_disposed_; 2196 2197 // The length of the retained_maps array at the time of context disposal. 2198 // This separates maps in the retained_maps array that were created before 2199 // and after context disposal. 2200 int number_of_disposed_maps_; 2201 2202 int global_ic_age_; 2203 2204 int scan_on_scavenge_pages_; 2205 2206 NewSpace new_space_; 2207 OldSpace* old_space_; 2208 OldSpace* code_space_; 2209 MapSpace* map_space_; 2210 LargeObjectSpace* lo_space_; 2211 HeapState gc_state_; 2212 int gc_post_processing_depth_; 2213 Address new_space_top_after_last_gc_; 2214 2215 // Returns the amount of external memory registered since last global gc. 2216 int64_t PromotedExternalMemorySize(); 2217 2218 // How many "runtime allocations" happened. 2219 uint32_t allocations_count_; 2220 2221 // Running hash over allocations performed. 2222 uint32_t raw_allocations_hash_; 2223 2224 // How many mark-sweep collections happened. 2225 unsigned int ms_count_; 2226 2227 // How many gc happened. 2228 unsigned int gc_count_; 2229 2230 // For post mortem debugging. 2231 int remembered_unmapped_pages_index_; 2232 Address remembered_unmapped_pages_[kRememberedUnmappedPages]; 2233 2234 #ifdef DEBUG 2235 // If the --gc-interval flag is set to a positive value, this 2236 // variable holds the value indicating the number of allocations 2237 // remain until the next failure and garbage collection. 2238 int allocation_timeout_; 2239 #endif // DEBUG 2240 2241 // Limit that triggers a global GC on the next (normally caused) GC. This 2242 // is checked when we have already decided to do a GC to help determine 2243 // which collector to invoke, before expanding a paged space in the old 2244 // generation and on every allocation in large object space. 2245 intptr_t old_generation_allocation_limit_; 2246 2247 // Indicates that an allocation has failed in the old generation since the 2248 // last GC. 2249 bool old_gen_exhausted_; 2250 2251 // Indicates that memory usage is more important than latency. 2252 // TODO(ulan): Merge it with memory reducer once chromium:490559 is fixed. 2253 bool optimize_for_memory_usage_; 2254 2255 // Indicates that inline bump-pointer allocation has been globally disabled 2256 // for all spaces. This is used to disable allocations in generated code. 2257 bool inline_allocation_disabled_; 2258 2259 // Weak list heads, threaded through the objects. 2260 // List heads are initialized lazily and contain the undefined_value at start. 2261 Object* native_contexts_list_; 2262 Object* allocation_sites_list_; 2263 2264 // List of encountered weak collections (JSWeakMap and JSWeakSet) during 2265 // marking. It is initialized during marking, destroyed after marking and 2266 // contains Smi(0) while marking is not active. 2267 Object* encountered_weak_collections_; 2268 2269 Object* encountered_weak_cells_; 2270 2271 Object* encountered_transition_arrays_; 2272 2273 StoreBufferRebuilder store_buffer_rebuilder_; 2274 2275 List<GCCallbackPair> gc_epilogue_callbacks_; 2276 List<GCCallbackPair> gc_prologue_callbacks_; 2277 2278 // Total RegExp code ever generated 2279 double total_regexp_code_generated_; 2280 2281 int deferred_counters_[v8::Isolate::kUseCounterFeatureCount]; 2282 2283 GCTracer* tracer_; 2284 2285 int high_survival_rate_period_length_; 2286 intptr_t promoted_objects_size_; 2287 double promotion_ratio_; 2288 double promotion_rate_; 2289 intptr_t semi_space_copied_object_size_; 2290 intptr_t previous_semi_space_copied_object_size_; 2291 double semi_space_copied_rate_; 2292 int nodes_died_in_new_space_; 2293 int nodes_copied_in_new_space_; 2294 int nodes_promoted_; 2295 2296 // This is the pretenuring trigger for allocation sites that are in maybe 2297 // tenure state. When we switched to the maximum new space size we deoptimize 2298 // the code that belongs to the allocation site and derive the lifetime 2299 // of the allocation site. 2300 unsigned int maximum_size_scavenges_; 2301 2302 // Maximum GC pause. 2303 double max_gc_pause_; 2304 2305 // Total time spent in GC. 2306 double total_gc_time_ms_; 2307 2308 // Maximum size of objects alive after GC. 2309 intptr_t max_alive_after_gc_; 2310 2311 // Minimal interval between two subsequent collections. 2312 double min_in_mutator_; 2313 2314 // Cumulative GC time spent in marking. 2315 double marking_time_; 2316 2317 // Cumulative GC time spent in sweeping. 2318 double sweeping_time_; 2319 2320 // Last time an idle notification happened. 2321 double last_idle_notification_time_; 2322 2323 // Last time a garbage collection happened. 2324 double last_gc_time_; 2325 2326 Scavenger* scavenge_collector_; 2327 2328 MarkCompactCollector* mark_compact_collector_; 2329 2330 StoreBuffer store_buffer_; 2331 2332 IncrementalMarking* incremental_marking_; 2333 2334 GCIdleTimeHandler* gc_idle_time_handler_; 2335 2336 MemoryReducer* memory_reducer_; 2337 2338 ObjectStats* object_stats_; 2339 2340 ScavengeJob* scavenge_job_; 2341 2342 InlineAllocationObserver* idle_scavenge_observer_; 2343 2344 // These two counters are monotomically increasing and never reset. 2345 size_t full_codegen_bytes_generated_; 2346 size_t crankshaft_codegen_bytes_generated_; 2347 2348 // This counter is increased before each GC and never reset. 2349 // To account for the bytes allocated since the last GC, use the 2350 // NewSpaceAllocationCounter() function. 2351 size_t new_space_allocation_counter_; 2352 2353 // This counter is increased before each GC and never reset. To 2354 // account for the bytes allocated since the last GC, use the 2355 // OldGenerationAllocationCounter() function. 2356 size_t old_generation_allocation_counter_; 2357 2358 // The size of objects in old generation after the last MarkCompact GC. 2359 size_t old_generation_size_at_last_gc_; 2360 2361 // If the --deopt_every_n_garbage_collections flag is set to a positive value, 2362 // this variable holds the number of garbage collections since the last 2363 // deoptimization triggered by garbage collection. 2364 int gcs_since_last_deopt_; 2365 2366 // The feedback storage is used to store allocation sites (keys) and how often 2367 // they have been visited (values) by finding a memento behind an object. The 2368 // storage is only alive temporary during a GC. The invariant is that all 2369 // pointers in this map are already fixed, i.e., they do not point to 2370 // forwarding pointers. 2371 HashMap* global_pretenuring_feedback_; 2372 2373 char trace_ring_buffer_[kTraceRingBufferSize]; 2374 // If it's not full then the data is from 0 to ring_buffer_end_. If it's 2375 // full then the data is from ring_buffer_end_ to the end of the buffer and 2376 // from 0 to ring_buffer_end_. 2377 bool ring_buffer_full_; 2378 size_t ring_buffer_end_; 2379 2380 // Shared state read by the scavenge collector and set by ScavengeObject. 2381 PromotionQueue promotion_queue_; 2382 2383 // Flag is set when the heap has been configured. The heap can be repeatedly 2384 // configured through the API until it is set up. 2385 bool configured_; 2386 2387 // Currently set GC flags that are respected by all GC components. 2388 int current_gc_flags_; 2389 2390 // Currently set GC callback flags that are used to pass information between 2391 // the embedder and V8's GC. 2392 GCCallbackFlags current_gc_callback_flags_; 2393 2394 ExternalStringTable external_string_table_; 2395 2396 MemoryChunk* chunks_queued_for_free_; 2397 2398 size_t concurrent_unmapping_tasks_active_; 2399 2400 base::Semaphore pending_unmapping_tasks_semaphore_; 2401 2402 base::Mutex relocation_mutex_; 2403 2404 int gc_callbacks_depth_; 2405 2406 bool deserialization_complete_; 2407 2408 StrongRootsList* strong_roots_list_; 2409 2410 ArrayBufferTracker* array_buffer_tracker_; 2411 2412 // The depth of HeapIterator nestings. 2413 int heap_iterator_depth_; 2414 2415 // Used for testing purposes. 2416 bool force_oom_; 2417 2418 // Classes in "heap" can be friends. 2419 friend class AlwaysAllocateScope; 2420 friend class GCCallbacksScope; 2421 friend class GCTracer; 2422 friend class HeapIterator; 2423 friend class IdleScavengeObserver; 2424 friend class IncrementalMarking; 2425 friend class IteratePointersToFromSpaceVisitor; 2426 friend class MarkCompactCollector; 2427 friend class MarkCompactMarkingVisitor; 2428 friend class NewSpace; 2429 friend class ObjectStatsVisitor; 2430 friend class Page; 2431 friend class Scavenger; 2432 friend class StoreBuffer; 2433 2434 // The allocator interface. 2435 friend class Factory; 2436 2437 // The Isolate constructs us. 2438 friend class Isolate; 2439 2440 // Used in cctest. 2441 friend class HeapTester; 2442 2443 DISALLOW_COPY_AND_ASSIGN(Heap); 2444 }; 2445 2446 2447 class HeapStats { 2448 public: 2449 static const int kStartMarker = 0xDECADE00; 2450 static const int kEndMarker = 0xDECADE01; 2451 2452 int* start_marker; // 0 2453 int* new_space_size; // 1 2454 int* new_space_capacity; // 2 2455 intptr_t* old_space_size; // 3 2456 intptr_t* old_space_capacity; // 4 2457 intptr_t* code_space_size; // 5 2458 intptr_t* code_space_capacity; // 6 2459 intptr_t* map_space_size; // 7 2460 intptr_t* map_space_capacity; // 8 2461 intptr_t* lo_space_size; // 9 2462 int* global_handle_count; // 10 2463 int* weak_global_handle_count; // 11 2464 int* pending_global_handle_count; // 12 2465 int* near_death_global_handle_count; // 13 2466 int* free_global_handle_count; // 14 2467 intptr_t* memory_allocator_size; // 15 2468 intptr_t* memory_allocator_capacity; // 16 2469 int* objects_per_type; // 17 2470 int* size_per_type; // 18 2471 int* os_error; // 19 2472 char* last_few_messages; // 20 2473 char* js_stacktrace; // 21 2474 int* end_marker; // 22 2475 }; 2476 2477 2478 class AlwaysAllocateScope { 2479 public: 2480 explicit inline AlwaysAllocateScope(Isolate* isolate); 2481 inline ~AlwaysAllocateScope(); 2482 2483 private: 2484 Heap* heap_; 2485 }; 2486 2487 2488 // Visitor class to verify interior pointers in spaces that do not contain 2489 // or care about intergenerational references. All heap object pointers have to 2490 // point into the heap to a location that has a map pointer at its first word. 2491 // Caveat: Heap::Contains is an approximation because it can return true for 2492 // objects in a heap space but above the allocation pointer. 2493 class VerifyPointersVisitor : public ObjectVisitor { 2494 public: 2495 inline void VisitPointers(Object** start, Object** end) override; 2496 }; 2497 2498 2499 // Verify that all objects are Smis. 2500 class VerifySmisVisitor : public ObjectVisitor { 2501 public: 2502 inline void VisitPointers(Object** start, Object** end) override; 2503 }; 2504 2505 2506 // Space iterator for iterating over all spaces of the heap. Returns each space 2507 // in turn, and null when it is done. 2508 class AllSpaces BASE_EMBEDDED { 2509 public: 2510 explicit AllSpaces(Heap* heap) : heap_(heap), counter_(FIRST_SPACE) {} 2511 Space* next(); 2512 2513 private: 2514 Heap* heap_; 2515 int counter_; 2516 }; 2517 2518 2519 // Space iterator for iterating over all old spaces of the heap: Old space 2520 // and code space. Returns each space in turn, and null when it is done. 2521 class OldSpaces BASE_EMBEDDED { 2522 public: 2523 explicit OldSpaces(Heap* heap) : heap_(heap), counter_(OLD_SPACE) {} 2524 OldSpace* next(); 2525 2526 private: 2527 Heap* heap_; 2528 int counter_; 2529 }; 2530 2531 2532 // Space iterator for iterating over all the paged spaces of the heap: Map 2533 // space, old space, code space and cell space. Returns 2534 // each space in turn, and null when it is done. 2535 class PagedSpaces BASE_EMBEDDED { 2536 public: 2537 explicit PagedSpaces(Heap* heap) : heap_(heap), counter_(OLD_SPACE) {} 2538 PagedSpace* next(); 2539 2540 private: 2541 Heap* heap_; 2542 int counter_; 2543 }; 2544 2545 2546 // Space iterator for iterating over all spaces of the heap. 2547 // For each space an object iterator is provided. The deallocation of the 2548 // returned object iterators is handled by the space iterator. 2549 class SpaceIterator : public Malloced { 2550 public: 2551 explicit SpaceIterator(Heap* heap); 2552 virtual ~SpaceIterator(); 2553 2554 bool has_next(); 2555 ObjectIterator* next(); 2556 2557 private: 2558 ObjectIterator* CreateIterator(); 2559 2560 Heap* heap_; 2561 int current_space_; // from enum AllocationSpace. 2562 ObjectIterator* iterator_; // object iterator for the current space. 2563 }; 2564 2565 2566 // A HeapIterator provides iteration over the whole heap. It 2567 // aggregates the specific iterators for the different spaces as 2568 // these can only iterate over one space only. 2569 // 2570 // HeapIterator ensures there is no allocation during its lifetime 2571 // (using an embedded DisallowHeapAllocation instance). 2572 // 2573 // HeapIterator can skip free list nodes (that is, de-allocated heap 2574 // objects that still remain in the heap). As implementation of free 2575 // nodes filtering uses GC marks, it can't be used during MS/MC GC 2576 // phases. Also, it is forbidden to interrupt iteration in this mode, 2577 // as this will leave heap objects marked (and thus, unusable). 2578 class HeapIterator BASE_EMBEDDED { 2579 public: 2580 enum HeapObjectsFiltering { kNoFiltering, kFilterUnreachable }; 2581 2582 explicit HeapIterator(Heap* heap, 2583 HeapObjectsFiltering filtering = kNoFiltering); 2584 ~HeapIterator(); 2585 2586 HeapObject* next(); 2587 2588 private: 2589 struct MakeHeapIterableHelper { 2590 explicit MakeHeapIterableHelper(Heap* heap) { heap->MakeHeapIterable(); } 2591 }; 2592 2593 HeapObject* NextObject(); 2594 2595 // The following two fields need to be declared in this order. Initialization 2596 // order guarantees that we first make the heap iterable (which may involve 2597 // allocations) and only then lock it down by not allowing further 2598 // allocations. 2599 MakeHeapIterableHelper make_heap_iterable_helper_; 2600 DisallowHeapAllocation no_heap_allocation_; 2601 2602 Heap* heap_; 2603 HeapObjectsFiltering filtering_; 2604 HeapObjectsFilter* filter_; 2605 // Space iterator for iterating all the spaces. 2606 SpaceIterator* space_iterator_; 2607 // Object iterator for the space currently being iterated. 2608 ObjectIterator* object_iterator_; 2609 }; 2610 2611 2612 // Cache for mapping (map, property name) into field offset. 2613 // Cleared at startup and prior to mark sweep collection. 2614 class KeyedLookupCache { 2615 public: 2616 // Lookup field offset for (map, name). If absent, -1 is returned. 2617 int Lookup(Handle<Map> map, Handle<Name> name); 2618 2619 // Update an element in the cache. 2620 void Update(Handle<Map> map, Handle<Name> name, int field_offset); 2621 2622 // Clear the cache. 2623 void Clear(); 2624 2625 static const int kLength = 256; 2626 static const int kCapacityMask = kLength - 1; 2627 static const int kMapHashShift = 5; 2628 static const int kHashMask = -4; // Zero the last two bits. 2629 static const int kEntriesPerBucket = 4; 2630 static const int kEntryLength = 2; 2631 static const int kMapIndex = 0; 2632 static const int kKeyIndex = 1; 2633 static const int kNotFound = -1; 2634 2635 // kEntriesPerBucket should be a power of 2. 2636 STATIC_ASSERT((kEntriesPerBucket & (kEntriesPerBucket - 1)) == 0); 2637 STATIC_ASSERT(kEntriesPerBucket == -kHashMask); 2638 2639 private: 2640 KeyedLookupCache() { 2641 for (int i = 0; i < kLength; ++i) { 2642 keys_[i].map = NULL; 2643 keys_[i].name = NULL; 2644 field_offsets_[i] = kNotFound; 2645 } 2646 } 2647 2648 static inline int Hash(Handle<Map> map, Handle<Name> name); 2649 2650 // Get the address of the keys and field_offsets arrays. Used in 2651 // generated code to perform cache lookups. 2652 Address keys_address() { return reinterpret_cast<Address>(&keys_); } 2653 2654 Address field_offsets_address() { 2655 return reinterpret_cast<Address>(&field_offsets_); 2656 } 2657 2658 struct Key { 2659 Map* map; 2660 Name* name; 2661 }; 2662 2663 Key keys_[kLength]; 2664 int field_offsets_[kLength]; 2665 2666 friend class ExternalReference; 2667 friend class Isolate; 2668 DISALLOW_COPY_AND_ASSIGN(KeyedLookupCache); 2669 }; 2670 2671 2672 // Cache for mapping (map, property name) into descriptor index. 2673 // The cache contains both positive and negative results. 2674 // Descriptor index equals kNotFound means the property is absent. 2675 // Cleared at startup and prior to any gc. 2676 class DescriptorLookupCache { 2677 public: 2678 // Lookup descriptor index for (map, name). 2679 // If absent, kAbsent is returned. 2680 inline int Lookup(Map* source, Name* name); 2681 2682 // Update an element in the cache. 2683 inline void Update(Map* source, Name* name, int result); 2684 2685 // Clear the cache. 2686 void Clear(); 2687 2688 static const int kAbsent = -2; 2689 2690 private: 2691 DescriptorLookupCache() { 2692 for (int i = 0; i < kLength; ++i) { 2693 keys_[i].source = NULL; 2694 keys_[i].name = NULL; 2695 results_[i] = kAbsent; 2696 } 2697 } 2698 2699 static int Hash(Object* source, Name* name) { 2700 // Uses only lower 32 bits if pointers are larger. 2701 uint32_t source_hash = 2702 static_cast<uint32_t>(reinterpret_cast<uintptr_t>(source)) >> 2703 kPointerSizeLog2; 2704 uint32_t name_hash = 2705 static_cast<uint32_t>(reinterpret_cast<uintptr_t>(name)) >> 2706 kPointerSizeLog2; 2707 return (source_hash ^ name_hash) % kLength; 2708 } 2709 2710 static const int kLength = 64; 2711 struct Key { 2712 Map* source; 2713 Name* name; 2714 }; 2715 2716 Key keys_[kLength]; 2717 int results_[kLength]; 2718 2719 friend class Isolate; 2720 DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache); 2721 }; 2722 2723 2724 // Abstract base class for checking whether a weak object should be retained. 2725 class WeakObjectRetainer { 2726 public: 2727 virtual ~WeakObjectRetainer() {} 2728 2729 // Return whether this object should be retained. If NULL is returned the 2730 // object has no references. Otherwise the address of the retained object 2731 // should be returned as in some GC situations the object has been moved. 2732 virtual Object* RetainAs(Object* object) = 0; 2733 }; 2734 2735 2736 #ifdef DEBUG 2737 // Helper class for tracing paths to a search target Object from all roots. 2738 // The TracePathFrom() method can be used to trace paths from a specific 2739 // object to the search target object. 2740 class PathTracer : public ObjectVisitor { 2741 public: 2742 enum WhatToFind { 2743 FIND_ALL, // Will find all matches. 2744 FIND_FIRST // Will stop the search after first match. 2745 }; 2746 2747 // Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject. 2748 static const int kMarkTag = 2; 2749 2750 // For the WhatToFind arg, if FIND_FIRST is specified, tracing will stop 2751 // after the first match. If FIND_ALL is specified, then tracing will be 2752 // done for all matches. 2753 PathTracer(Object* search_target, WhatToFind what_to_find, 2754 VisitMode visit_mode) 2755 : search_target_(search_target), 2756 found_target_(false), 2757 found_target_in_trace_(false), 2758 what_to_find_(what_to_find), 2759 visit_mode_(visit_mode), 2760 object_stack_(20), 2761 no_allocation() {} 2762 2763 void VisitPointers(Object** start, Object** end) override; 2764 2765 void Reset(); 2766 void TracePathFrom(Object** root); 2767 2768 bool found() const { return found_target_; } 2769 2770 static Object* const kAnyGlobalObject; 2771 2772 protected: 2773 class MarkVisitor; 2774 class UnmarkVisitor; 2775 2776 void MarkRecursively(Object** p, MarkVisitor* mark_visitor); 2777 void UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor); 2778 virtual void ProcessResults(); 2779 2780 Object* search_target_; 2781 bool found_target_; 2782 bool found_target_in_trace_; 2783 WhatToFind what_to_find_; 2784 VisitMode visit_mode_; 2785 List<Object*> object_stack_; 2786 2787 DisallowHeapAllocation no_allocation; // i.e. no gc allowed. 2788 2789 private: 2790 DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer); 2791 }; 2792 #endif // DEBUG 2793 } // namespace internal 2794 } // namespace v8 2795 2796 #endif // V8_HEAP_HEAP_H_ 2797
