1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 #include "allocation.h"
34 #include "assert-scope.h"
36 #include "incremental-marking.h"
38 #include "mark-compact.h"
39 #include "objects-visiting.h"
41 #include "splay-tree-inl.h"
42 #include "store-buffer.h"
43 #include "v8-counters.h"
44 #include "v8globals.h"
49 // Defines all the roots in Heap.
50 #define STRONG_ROOT_LIST(V) \
51 V(Map, byte_array_map, ByteArrayMap) \
52 V(Map, free_space_map, FreeSpaceMap) \
53 V(Map, one_pointer_filler_map, OnePointerFillerMap) \
54 V(Map, two_pointer_filler_map, TwoPointerFillerMap) \
55 /* Cluster the most popular ones in a few cache lines here at the top. */ \
56 V(Smi, store_buffer_top, StoreBufferTop) \
57 V(Oddball, undefined_value, UndefinedValue) \
58 V(Oddball, the_hole_value, TheHoleValue) \
59 V(Oddball, null_value, NullValue) \
60 V(Oddball, true_value, TrueValue) \
61 V(Oddball, false_value, FalseValue) \
62 V(Oddball, uninitialized_value, UninitializedValue) \
63 V(Map, cell_map, CellMap) \
64 V(Map, global_property_cell_map, GlobalPropertyCellMap) \
65 V(Map, shared_function_info_map, SharedFunctionInfoMap) \
66 V(Map, meta_map, MetaMap) \
67 V(Map, heap_number_map, HeapNumberMap) \
68 V(Map, native_context_map, NativeContextMap) \
69 V(Map, fixed_array_map, FixedArrayMap) \
70 V(Map, code_map, CodeMap) \
71 V(Map, scope_info_map, ScopeInfoMap) \
72 V(Map, fixed_cow_array_map, FixedCOWArrayMap) \
73 V(Map, fixed_double_array_map, FixedDoubleArrayMap) \
74 V(Map, constant_pool_array_map, ConstantPoolArrayMap) \
75 V(Object, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \
76 V(Map, hash_table_map, HashTableMap) \
77 V(FixedArray, empty_fixed_array, EmptyFixedArray) \
78 V(ByteArray, empty_byte_array, EmptyByteArray) \
79 V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
80 V(ConstantPoolArray, empty_constant_pool_array, EmptyConstantPoolArray) \
81 V(Smi, stack_limit, StackLimit) \
82 V(Oddball, arguments_marker, ArgumentsMarker) \
83 /* The roots above this line should be boring from a GC point of view. */ \
84 /* This means they are never in new space and never on a page that is */ \
85 /* being compacted. */ \
86 V(FixedArray, number_string_cache, NumberStringCache) \
87 V(Object, instanceof_cache_function, InstanceofCacheFunction) \
88 V(Object, instanceof_cache_map, InstanceofCacheMap) \
89 V(Object, instanceof_cache_answer, InstanceofCacheAnswer) \
90 V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \
91 V(FixedArray, string_split_cache, StringSplitCache) \
92 V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \
93 V(Object, termination_exception, TerminationException) \
94 V(Smi, hash_seed, HashSeed) \
95 V(Map, symbol_map, SymbolMap) \
96 V(Map, string_map, StringMap) \
97 V(Map, ascii_string_map, AsciiStringMap) \
98 V(Map, cons_string_map, ConsStringMap) \
99 V(Map, cons_ascii_string_map, ConsAsciiStringMap) \
100 V(Map, sliced_string_map, SlicedStringMap) \
101 V(Map, sliced_ascii_string_map, SlicedAsciiStringMap) \
102 V(Map, external_string_map, ExternalStringMap) \
104 external_string_with_one_byte_data_map, \
105 ExternalStringWithOneByteDataMap) \
106 V(Map, external_ascii_string_map, ExternalAsciiStringMap) \
107 V(Map, short_external_string_map, ShortExternalStringMap) \
109 short_external_string_with_one_byte_data_map, \
110 ShortExternalStringWithOneByteDataMap) \
111 V(Map, internalized_string_map, InternalizedStringMap) \
112 V(Map, ascii_internalized_string_map, AsciiInternalizedStringMap) \
113 V(Map, cons_internalized_string_map, ConsInternalizedStringMap) \
114 V(Map, cons_ascii_internalized_string_map, ConsAsciiInternalizedStringMap) \
116 external_internalized_string_map, \
117 ExternalInternalizedStringMap) \
119 external_internalized_string_with_one_byte_data_map, \
120 ExternalInternalizedStringWithOneByteDataMap) \
122 external_ascii_internalized_string_map, \
123 ExternalAsciiInternalizedStringMap) \
125 short_external_internalized_string_map, \
126 ShortExternalInternalizedStringMap) \
128 short_external_internalized_string_with_one_byte_data_map, \
129 ShortExternalInternalizedStringWithOneByteDataMap) \
131 short_external_ascii_internalized_string_map, \
132 ShortExternalAsciiInternalizedStringMap) \
133 V(Map, short_external_ascii_string_map, ShortExternalAsciiStringMap) \
134 V(Map, undetectable_string_map, UndetectableStringMap) \
135 V(Map, undetectable_ascii_string_map, UndetectableAsciiStringMap) \
136 V(Map, external_int8_array_map, ExternalInt8ArrayMap) \
137 V(Map, external_uint8_array_map, ExternalUint8ArrayMap) \
138 V(Map, external_int16_array_map, ExternalInt16ArrayMap) \
139 V(Map, external_uint16_array_map, ExternalUint16ArrayMap) \
140 V(Map, external_int32_array_map, ExternalInt32ArrayMap) \
141 V(Map, external_uint32_array_map, ExternalUint32ArrayMap) \
142 V(Map, external_float32_array_map, ExternalFloat32ArrayMap) \
143 V(Map, external_float64_array_map, ExternalFloat64ArrayMap) \
144 V(Map, external_uint8_clamped_array_map, ExternalUint8ClampedArrayMap) \
145 V(ExternalArray, empty_external_int8_array, \
146 EmptyExternalInt8Array) \
147 V(ExternalArray, empty_external_uint8_array, \
148 EmptyExternalUint8Array) \
149 V(ExternalArray, empty_external_int16_array, EmptyExternalInt16Array) \
150 V(ExternalArray, empty_external_uint16_array, \
151 EmptyExternalUint16Array) \
152 V(ExternalArray, empty_external_int32_array, EmptyExternalInt32Array) \
153 V(ExternalArray, empty_external_uint32_array, \
154 EmptyExternalUint32Array) \
155 V(ExternalArray, empty_external_float32_array, EmptyExternalFloat32Array) \
156 V(ExternalArray, empty_external_float64_array, EmptyExternalFloat64Array) \
157 V(ExternalArray, empty_external_uint8_clamped_array, \
158 EmptyExternalUint8ClampedArray) \
159 V(Map, fixed_uint8_array_map, FixedUint8ArrayMap) \
160 V(Map, fixed_int8_array_map, FixedInt8ArrayMap) \
161 V(Map, fixed_uint16_array_map, FixedUint16ArrayMap) \
162 V(Map, fixed_int16_array_map, FixedInt16ArrayMap) \
163 V(Map, fixed_uint32_array_map, FixedUint32ArrayMap) \
164 V(Map, fixed_int32_array_map, FixedInt32ArrayMap) \
165 V(Map, fixed_float32_array_map, FixedFloat32ArrayMap) \
166 V(Map, fixed_float64_array_map, FixedFloat64ArrayMap) \
167 V(Map, fixed_uint8_clamped_array_map, FixedUint8ClampedArrayMap) \
168 V(Map, non_strict_arguments_elements_map, NonStrictArgumentsElementsMap) \
169 V(Map, function_context_map, FunctionContextMap) \
170 V(Map, catch_context_map, CatchContextMap) \
171 V(Map, with_context_map, WithContextMap) \
172 V(Map, block_context_map, BlockContextMap) \
173 V(Map, module_context_map, ModuleContextMap) \
174 V(Map, global_context_map, GlobalContextMap) \
175 V(Map, oddball_map, OddballMap) \
176 V(Map, message_object_map, JSMessageObjectMap) \
177 V(Map, foreign_map, ForeignMap) \
178 V(HeapNumber, nan_value, NanValue) \
179 V(HeapNumber, infinity_value, InfinityValue) \
180 V(HeapNumber, minus_zero_value, MinusZeroValue) \
181 V(Map, neander_map, NeanderMap) \
182 V(JSObject, message_listeners, MessageListeners) \
183 V(UnseededNumberDictionary, code_stubs, CodeStubs) \
184 V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache) \
185 V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache) \
186 V(Code, js_entry_code, JsEntryCode) \
187 V(Code, js_construct_entry_code, JsConstructEntryCode) \
188 V(FixedArray, natives_source_cache, NativesSourceCache) \
189 V(Smi, last_script_id, LastScriptId) \
190 V(Script, empty_script, EmptyScript) \
191 V(Smi, real_stack_limit, RealStackLimit) \
192 V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \
193 V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
194 V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset) \
195 V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset) \
196 V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset) \
197 V(Cell, undefined_cell, UndefineCell) \
198 V(JSObject, observation_state, ObservationState) \
199 V(Map, external_map, ExternalMap) \
200 V(Symbol, frozen_symbol, FrozenSymbol) \
201 V(Symbol, elements_transition_symbol, ElementsTransitionSymbol) \
202 V(SeededNumberDictionary, empty_slow_element_dictionary, \
203 EmptySlowElementDictionary) \
204 V(Symbol, observed_symbol, ObservedSymbol)
206 #define ROOT_LIST(V) \
207 STRONG_ROOT_LIST(V) \
208 V(StringTable, string_table, StringTable)
210 #define INTERNALIZED_STRING_LIST(V) \
211 V(Array_string, "Array") \
212 V(Object_string, "Object") \
213 V(proto_string, "__proto__") \
214 V(arguments_string, "arguments") \
215 V(Arguments_string, "Arguments") \
216 V(call_string, "call") \
217 V(apply_string, "apply") \
218 V(caller_string, "caller") \
219 V(boolean_string, "boolean") \
220 V(Boolean_string, "Boolean") \
221 V(callee_string, "callee") \
222 V(constructor_string, "constructor") \
223 V(dot_result_string, ".result") \
224 V(dot_for_string, ".for.") \
225 V(dot_iterator_string, ".iterator") \
226 V(dot_generator_object_string, ".generator_object") \
227 V(eval_string, "eval") \
228 V(empty_string, "") \
229 V(function_string, "function") \
230 V(length_string, "length") \
231 V(module_string, "module") \
232 V(name_string, "name") \
233 V(native_string, "native") \
234 V(null_string, "null") \
235 V(number_string, "number") \
236 V(Number_string, "Number") \
237 V(nan_string, "NaN") \
238 V(RegExp_string, "RegExp") \
239 V(source_string, "source") \
240 V(global_string, "global") \
241 V(ignore_case_string, "ignoreCase") \
242 V(multiline_string, "multiline") \
243 V(input_string, "input") \
244 V(index_string, "index") \
245 V(last_index_string, "lastIndex") \
246 V(object_string, "object") \
247 V(literals_string, "literals") \
248 V(prototype_string, "prototype") \
249 V(string_string, "string") \
250 V(String_string, "String") \
251 V(symbol_string, "symbol") \
252 V(Symbol_string, "Symbol") \
253 V(Date_string, "Date") \
254 V(this_string, "this") \
255 V(to_string_string, "toString") \
256 V(char_at_string, "CharAt") \
257 V(undefined_string, "undefined") \
258 V(value_of_string, "valueOf") \
259 V(stack_string, "stack") \
260 V(toJSON_string, "toJSON") \
261 V(InitializeVarGlobal_string, "InitializeVarGlobal") \
262 V(InitializeConstGlobal_string, "InitializeConstGlobal") \
263 V(KeyedLoadElementMonomorphic_string, \
264 "KeyedLoadElementMonomorphic") \
265 V(KeyedStoreElementMonomorphic_string, \
266 "KeyedStoreElementMonomorphic") \
267 V(stack_overflow_string, "kStackOverflowBoilerplate") \
268 V(illegal_access_string, "illegal access") \
269 V(illegal_execution_state_string, "illegal execution state") \
270 V(get_string, "get") \
271 V(set_string, "set") \
272 V(map_field_string, "%map") \
273 V(elements_field_string, "%elements") \
274 V(length_field_string, "%length") \
275 V(cell_value_string, "%cell_value") \
276 V(function_class_string, "Function") \
277 V(illegal_argument_string, "illegal argument") \
278 V(MakeReferenceError_string, "MakeReferenceError") \
279 V(MakeSyntaxError_string, "MakeSyntaxError") \
280 V(MakeTypeError_string, "MakeTypeError") \
281 V(invalid_lhs_in_assignment_string, "invalid_lhs_in_assignment") \
282 V(invalid_lhs_in_for_in_string, "invalid_lhs_in_for_in") \
283 V(invalid_lhs_in_postfix_op_string, "invalid_lhs_in_postfix_op") \
284 V(invalid_lhs_in_prefix_op_string, "invalid_lhs_in_prefix_op") \
285 V(illegal_return_string, "illegal_return") \
286 V(illegal_break_string, "illegal_break") \
287 V(illegal_continue_string, "illegal_continue") \
288 V(unknown_label_string, "unknown_label") \
289 V(redeclaration_string, "redeclaration") \
290 V(space_string, " ") \
291 V(exec_string, "exec") \
292 V(zero_string, "0") \
293 V(global_eval_string, "GlobalEval") \
294 V(identity_hash_string, "v8::IdentityHash") \
295 V(closure_string, "(closure)") \
296 V(use_strict_string, "use strict") \
298 V(anonymous_function_string, "(anonymous function)") \
299 V(compare_ic_string, "==") \
300 V(strict_compare_ic_string, "===") \
301 V(infinity_string, "Infinity") \
302 V(minus_infinity_string, "-Infinity") \
303 V(hidden_stack_trace_string, "v8::hidden_stack_trace") \
304 V(query_colon_string, "(?:)") \
305 V(Generator_string, "Generator") \
306 V(throw_string, "throw") \
307 V(done_string, "done") \
308 V(value_string, "value") \
309 V(next_string, "next") \
310 V(byte_length_string, "byteLength") \
311 V(byte_offset_string, "byteOffset") \
312 V(buffer_string, "buffer")
314 // Forward declarations.
318 class WeakObjectRetainer;
321 typedef String* (*ExternalStringTableUpdaterCallback)(Heap* heap,
324 class StoreBufferRebuilder {
326 explicit StoreBufferRebuilder(StoreBuffer* store_buffer)
327 : store_buffer_(store_buffer) {
330 void Callback(MemoryChunk* page, StoreBufferEvent event);
333 StoreBuffer* store_buffer_;
335 // We record in this variable how full the store buffer was when we started
336 // iterating over the current page, finding pointers to new space. If the
337 // store buffer overflows again we can exempt the page from the store buffer
338 // by rewinding to this point instead of having to search the store buffer.
339 Object*** start_of_current_page_;
340 // The current page we are scanning in the store buffer iterator.
341 MemoryChunk* current_page_;
346 // A queue of objects promoted during scavenge. Each object is accompanied
347 // by it's size to avoid dereferencing a map pointer for scanning.
348 class PromotionQueue {
350 explicit PromotionQueue(Heap* heap)
361 delete emergency_stack_;
362 emergency_stack_ = NULL;
365 inline void ActivateGuardIfOnTheSamePage();
367 Page* GetHeadPage() {
368 return Page::FromAllocationTop(reinterpret_cast<Address>(rear_));
371 void SetNewLimit(Address limit) {
376 ASSERT(GetHeadPage() == Page::FromAllocationTop(limit));
377 limit_ = reinterpret_cast<intptr_t*>(limit);
379 if (limit_ <= rear_) {
387 return (front_ == rear_) &&
388 (emergency_stack_ == NULL || emergency_stack_->length() == 0);
391 inline void insert(HeapObject* target, int size);
393 void remove(HeapObject** target, int* size) {
395 if (front_ == rear_) {
396 Entry e = emergency_stack_->RemoveLast();
402 if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(front_))) {
403 NewSpacePage* front_page =
404 NewSpacePage::FromAddress(reinterpret_cast<Address>(front_));
405 ASSERT(!front_page->prev_page()->is_anchor());
407 reinterpret_cast<intptr_t*>(front_page->prev_page()->area_end());
409 *target = reinterpret_cast<HeapObject*>(*(--front_));
410 *size = static_cast<int>(*(--front_));
411 // Assert no underflow.
412 SemiSpace::AssertValidRange(reinterpret_cast<Address>(rear_),
413 reinterpret_cast<Address>(front_));
417 // The front of the queue is higher in the memory page chain than the rear.
424 static const int kEntrySizeInWords = 2;
427 Entry(HeapObject* obj, int size) : obj_(obj), size_(size) { }
432 List<Entry>* emergency_stack_;
436 void RelocateQueueHead();
438 DISALLOW_COPY_AND_ASSIGN(PromotionQueue);
442 typedef void (*ScavengingCallback)(Map* map,
447 // External strings table is a place where all external strings are
448 // registered. We need to keep track of such strings to properly
450 class ExternalStringTable {
452 // Registers an external string.
453 inline void AddString(String* string);
455 inline void Iterate(ObjectVisitor* v);
457 // Restores internal invariant and gets rid of collected strings.
458 // Must be called after each Iterate() that modified the strings.
461 // Destroys all allocated memory.
465 explicit ExternalStringTable(Heap* heap) : heap_(heap) { }
469 inline void Verify();
471 inline void AddOldString(String* string);
473 // Notifies the table that only a prefix of the new list is valid.
474 inline void ShrinkNewStrings(int position);
476 // To speed up scavenge collections new space string are kept
477 // separate from old space strings.
478 List<Object*> new_space_strings_;
479 List<Object*> old_space_strings_;
483 DISALLOW_COPY_AND_ASSIGN(ExternalStringTable);
487 enum ArrayStorageAllocationMode {
488 DONT_INITIALIZE_ARRAY_ELEMENTS,
489 INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE
495 // Configure heap size before setup. Return false if the heap has been
497 bool ConfigureHeap(int max_semispace_size,
498 intptr_t max_old_gen_size,
499 intptr_t max_executable_size);
500 bool ConfigureHeapDefault();
502 // Prepares the heap, setting up memory areas that are needed in the isolate
503 // without actually creating any objects.
506 // Bootstraps the object heap with the core set of objects required to run.
507 // Returns whether it succeeded.
508 bool CreateHeapObjects();
510 // Destroys all memory allocated by the heap.
513 // Set the stack limit in the roots_ array. Some architectures generate
514 // code that looks here, because it is faster than loading from the static
515 // jslimit_/real_jslimit_ variable in the StackGuard.
516 void SetStackLimits();
518 // Returns whether SetUp has been called.
521 // Returns the maximum amount of memory reserved for the heap. For
522 // the young generation, we reserve 4 times the amount needed for a
523 // semi space. The young generation consists of two semi spaces and
524 // we reserve twice the amount needed for those in order to ensure
525 // that new space can be aligned to its size.
526 intptr_t MaxReserved() {
527 return 4 * reserved_semispace_size_ + max_old_generation_size_;
529 int MaxSemiSpaceSize() { return max_semispace_size_; }
530 int ReservedSemiSpaceSize() { return reserved_semispace_size_; }
531 int InitialSemiSpaceSize() { return initial_semispace_size_; }
532 intptr_t MaxOldGenerationSize() { return max_old_generation_size_; }
533 intptr_t MaxExecutableSize() { return max_executable_size_; }
535 // Returns the capacity of the heap in bytes w/o growing. Heap grows when
536 // more spaces are needed until it reaches the limit.
539 // Returns the amount of memory currently committed for the heap.
540 intptr_t CommittedMemory();
542 // Returns the amount of executable memory currently committed for the heap.
543 intptr_t CommittedMemoryExecutable();
545 // Returns the amount of phyical memory currently committed for the heap.
546 size_t CommittedPhysicalMemory();
548 // Returns the maximum amount of memory ever committed for the heap.
549 intptr_t MaximumCommittedMemory() { return maximum_committed_; }
551 // Updates the maximum committed memory for the heap. Should be called
552 // whenever a space grows.
553 void UpdateMaximumCommitted();
555 // Returns the available bytes in space w/o growing.
556 // Heap doesn't guarantee that it can allocate an object that requires
557 // all available bytes. Check MaxHeapObjectSize() instead.
558 intptr_t Available();
560 // Returns of size of all objects residing in the heap.
561 intptr_t SizeOfObjects();
563 // Return the starting address and a mask for the new space. And-masking an
564 // address with the mask will result in the start address of the new space
565 // for all addresses in either semispace.
566 Address NewSpaceStart() { return new_space_.start(); }
567 uintptr_t NewSpaceMask() { return new_space_.mask(); }
568 Address NewSpaceTop() { return new_space_.top(); }
570 NewSpace* new_space() { return &new_space_; }
571 OldSpace* old_pointer_space() { return old_pointer_space_; }
572 OldSpace* old_data_space() { return old_data_space_; }
573 OldSpace* code_space() { return code_space_; }
574 MapSpace* map_space() { return map_space_; }
575 CellSpace* cell_space() { return cell_space_; }
576 PropertyCellSpace* property_cell_space() {
577 return property_cell_space_;
579 LargeObjectSpace* lo_space() { return lo_space_; }
580 PagedSpace* paged_space(int idx) {
582 case OLD_POINTER_SPACE:
583 return old_pointer_space();
585 return old_data_space();
590 case PROPERTY_CELL_SPACE:
591 return property_cell_space();
601 bool always_allocate() { return always_allocate_scope_depth_ != 0; }
602 Address always_allocate_scope_depth_address() {
603 return reinterpret_cast<Address>(&always_allocate_scope_depth_);
605 bool linear_allocation() {
606 return linear_allocation_scope_depth_ != 0;
609 Address* NewSpaceAllocationTopAddress() {
610 return new_space_.allocation_top_address();
612 Address* NewSpaceAllocationLimitAddress() {
613 return new_space_.allocation_limit_address();
616 Address* OldPointerSpaceAllocationTopAddress() {
617 return old_pointer_space_->allocation_top_address();
619 Address* OldPointerSpaceAllocationLimitAddress() {
620 return old_pointer_space_->allocation_limit_address();
623 Address* OldDataSpaceAllocationTopAddress() {
624 return old_data_space_->allocation_top_address();
626 Address* OldDataSpaceAllocationLimitAddress() {
627 return old_data_space_->allocation_limit_address();
630 // Allocates and initializes a new JavaScript object based on a
632 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
634 // Please note this does not perform a garbage collection.
635 MUST_USE_RESULT MaybeObject* AllocateJSObject(
636 JSFunction* constructor,
637 PretenureFlag pretenure = NOT_TENURED);
639 MUST_USE_RESULT MaybeObject* AllocateJSObjectWithAllocationSite(
640 JSFunction* constructor,
641 Handle<AllocationSite> allocation_site);
643 MUST_USE_RESULT MaybeObject* AllocateJSModule(Context* context,
644 ScopeInfo* scope_info);
646 // Allocate a JSArray with no elements
647 MUST_USE_RESULT MaybeObject* AllocateEmptyJSArray(
648 ElementsKind elements_kind,
649 PretenureFlag pretenure = NOT_TENURED) {
650 return AllocateJSArrayAndStorage(elements_kind, 0, 0,
651 DONT_INITIALIZE_ARRAY_ELEMENTS,
655 // Allocate a JSArray with a specified length but elements that are left
657 MUST_USE_RESULT MaybeObject* AllocateJSArrayAndStorage(
658 ElementsKind elements_kind,
661 ArrayStorageAllocationMode mode = DONT_INITIALIZE_ARRAY_ELEMENTS,
662 PretenureFlag pretenure = NOT_TENURED);
664 MUST_USE_RESULT MaybeObject* AllocateJSArrayStorage(
668 ArrayStorageAllocationMode mode = DONT_INITIALIZE_ARRAY_ELEMENTS);
670 // Allocate a JSArray with no elements
671 MUST_USE_RESULT MaybeObject* AllocateJSArrayWithElements(
672 FixedArrayBase* array_base,
673 ElementsKind elements_kind,
675 PretenureFlag pretenure = NOT_TENURED);
677 // Returns a deep copy of the JavaScript object.
678 // Properties and elements are copied too.
679 // Returns failure if allocation failed.
680 // Optionally takes an AllocationSite to be appended in an AllocationMemento.
681 MUST_USE_RESULT MaybeObject* CopyJSObject(JSObject* source,
682 AllocationSite* site = NULL);
684 // Allocates a JS ArrayBuffer object.
685 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
687 // Please note this does not perform a garbage collection.
688 MUST_USE_RESULT MaybeObject* AllocateJSArrayBuffer();
690 // Allocates a Harmony proxy or function proxy.
691 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
693 // Please note this does not perform a garbage collection.
694 MUST_USE_RESULT MaybeObject* AllocateJSProxy(Object* handler,
697 MUST_USE_RESULT MaybeObject* AllocateJSFunctionProxy(Object* handler,
699 Object* construct_trap,
702 // Reinitialize a JSReceiver into an (empty) JS object of respective type and
703 // size, but keeping the original prototype. The receiver must have at least
704 // the size of the new object. The object is reinitialized and behaves as an
705 // object that has been freshly allocated.
706 // Returns failure if an error occured, otherwise object.
707 MUST_USE_RESULT MaybeObject* ReinitializeJSReceiver(JSReceiver* object,
711 // Reinitialize an JSGlobalProxy based on a constructor. The object
712 // must have the same size as objects allocated using the
713 // constructor. The object is reinitialized and behaves as an
714 // object that has been freshly allocated using the constructor.
715 MUST_USE_RESULT MaybeObject* ReinitializeJSGlobalProxy(
716 JSFunction* constructor, JSGlobalProxy* global);
718 // Allocates and initializes a new JavaScript object based on a map.
719 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
721 // Please note this does not perform a garbage collection.
722 MUST_USE_RESULT MaybeObject* AllocateJSObjectFromMap(
723 Map* map, PretenureFlag pretenure = NOT_TENURED, bool alloc_props = true);
725 MUST_USE_RESULT MaybeObject* AllocateJSObjectFromMapWithAllocationSite(
726 Map* map, Handle<AllocationSite> allocation_site);
728 // Allocates a heap object based on the map.
729 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
731 // Please note this function does not perform a garbage collection.
732 MUST_USE_RESULT MaybeObject* Allocate(Map* map, AllocationSpace space);
734 MUST_USE_RESULT MaybeObject* AllocateWithAllocationSite(Map* map,
735 AllocationSpace space, Handle<AllocationSite> allocation_site);
737 // Allocates a JS Map in the heap.
738 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
740 // Please note this function does not perform a garbage collection.
741 MUST_USE_RESULT MaybeObject* AllocateMap(
742 InstanceType instance_type,
744 ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND);
746 // Allocates a partial map for bootstrapping.
747 MUST_USE_RESULT MaybeObject* AllocatePartialMap(InstanceType instance_type,
750 // Allocates an empty code cache.
751 MUST_USE_RESULT MaybeObject* AllocateCodeCache();
753 // Allocates a serialized scope info.
754 MUST_USE_RESULT MaybeObject* AllocateScopeInfo(int length);
756 // Allocates an External object for v8's external API.
757 MUST_USE_RESULT MaybeObject* AllocateExternal(void* value);
759 // Allocates an empty PolymorphicCodeCache.
760 MUST_USE_RESULT MaybeObject* AllocatePolymorphicCodeCache();
762 // Allocates a pre-tenured empty AccessorPair.
763 MUST_USE_RESULT MaybeObject* AllocateAccessorPair();
765 // Allocates an empty TypeFeedbackInfo.
766 MUST_USE_RESULT MaybeObject* AllocateTypeFeedbackInfo();
768 // Allocates an AliasedArgumentsEntry.
769 MUST_USE_RESULT MaybeObject* AllocateAliasedArgumentsEntry(int slot);
771 // Clear the Instanceof cache (used when a prototype changes).
772 inline void ClearInstanceofCache();
774 // Iterates the whole code space to clear all ICs of the given kind.
775 void ClearAllICsByKind(Code::Kind kind);
777 // For use during bootup.
778 void RepairFreeListsAfterBoot();
780 // Allocates and fully initializes a String. There are two String
781 // encodings: ASCII and two byte. One should choose between the three string
782 // allocation functions based on the encoding of the string buffer used to
783 // initialized the string.
784 // - ...FromAscii initializes the string from a buffer that is ASCII
785 // encoded (it does not check that the buffer is ASCII encoded) and the
786 // result will be ASCII encoded.
787 // - ...FromUTF8 initializes the string from a buffer that is UTF-8
788 // encoded. If the characters are all single-byte characters, the
789 // result will be ASCII encoded, otherwise it will converted to two
791 // - ...FromTwoByte initializes the string from a buffer that is two-byte
792 // encoded. If the characters are all single-byte characters, the
793 // result will be converted to ASCII, otherwise it will be left as
795 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
797 // Please note this does not perform a garbage collection.
798 MUST_USE_RESULT MaybeObject* AllocateStringFromOneByte(
799 Vector<const uint8_t> str,
800 PretenureFlag pretenure = NOT_TENURED);
801 // TODO(dcarney): remove this function.
802 MUST_USE_RESULT inline MaybeObject* AllocateStringFromOneByte(
803 Vector<const char> str,
804 PretenureFlag pretenure = NOT_TENURED) {
805 return AllocateStringFromOneByte(Vector<const uint8_t>::cast(str),
808 MUST_USE_RESULT inline MaybeObject* AllocateStringFromUtf8(
809 Vector<const char> str,
810 PretenureFlag pretenure = NOT_TENURED);
811 MUST_USE_RESULT MaybeObject* AllocateStringFromUtf8Slow(
812 Vector<const char> str,
814 PretenureFlag pretenure = NOT_TENURED);
815 MUST_USE_RESULT MaybeObject* AllocateStringFromTwoByte(
816 Vector<const uc16> str,
817 PretenureFlag pretenure = NOT_TENURED);
819 // Allocates an internalized string in old space based on the character
820 // stream. Returns Failure::RetryAfterGC(requested_bytes, space) if the
821 // allocation failed.
822 // Please note this function does not perform a garbage collection.
823 MUST_USE_RESULT inline MaybeObject* AllocateInternalizedStringFromUtf8(
824 Vector<const char> str,
826 uint32_t hash_field);
828 MUST_USE_RESULT inline MaybeObject* AllocateOneByteInternalizedString(
829 Vector<const uint8_t> str,
830 uint32_t hash_field);
832 MUST_USE_RESULT inline MaybeObject* AllocateTwoByteInternalizedString(
833 Vector<const uc16> str,
834 uint32_t hash_field);
837 static inline bool IsOneByte(T t, int chars);
840 MUST_USE_RESULT inline MaybeObject* AllocateInternalizedStringImpl(
841 T t, int chars, uint32_t hash_field);
843 template<bool is_one_byte, typename T>
844 MUST_USE_RESULT MaybeObject* AllocateInternalizedStringImpl(
845 T t, int chars, uint32_t hash_field);
847 // Allocates and partially initializes a String. There are two String
848 // encodings: ASCII and two byte. These functions allocate a string of the
849 // given length and set its map and length fields. The characters of the
850 // string are uninitialized.
851 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
853 // Please note this does not perform a garbage collection.
854 MUST_USE_RESULT MaybeObject* AllocateRawOneByteString(
856 PretenureFlag pretenure = NOT_TENURED);
857 MUST_USE_RESULT MaybeObject* AllocateRawTwoByteString(
859 PretenureFlag pretenure = NOT_TENURED);
861 // Computes a single character string where the character has code.
862 // A cache is used for ASCII codes.
863 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
864 // failed. Please note this does not perform a garbage collection.
865 MUST_USE_RESULT MaybeObject* LookupSingleCharacterStringFromCode(
868 // Allocate a byte array of the specified length
869 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
871 // Please note this does not perform a garbage collection.
872 MUST_USE_RESULT MaybeObject* AllocateByteArray(
874 PretenureFlag pretenure = NOT_TENURED);
876 // Allocates an external array of the specified length and type.
877 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
879 // Please note this does not perform a garbage collection.
880 MUST_USE_RESULT MaybeObject* AllocateExternalArray(
882 ExternalArrayType array_type,
883 void* external_pointer,
884 PretenureFlag pretenure);
886 // Allocates a fixed typed array of the specified length and type.
887 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
889 // Please note this does not perform a garbage collection.
890 MUST_USE_RESULT MaybeObject* AllocateFixedTypedArray(
892 ExternalArrayType array_type,
893 PretenureFlag pretenure);
895 // Allocate a symbol in old space.
896 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
898 // Please note this does not perform a garbage collection.
899 MUST_USE_RESULT MaybeObject* AllocateSymbol();
900 MUST_USE_RESULT MaybeObject* AllocatePrivateSymbol();
902 // Allocate a tenured AllocationSite. It's payload is null
903 MUST_USE_RESULT MaybeObject* AllocateAllocationSite();
905 // Allocates a fixed array initialized with undefined values
906 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
908 // Please note this does not perform a garbage collection.
909 MUST_USE_RESULT MaybeObject* AllocateFixedArray(
911 PretenureFlag pretenure = NOT_TENURED);
913 // Allocates an uninitialized fixed array. It must be filled by the caller.
915 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
917 // Please note this does not perform a garbage collection.
918 MUST_USE_RESULT MaybeObject* AllocateUninitializedFixedArray(int length);
920 // Move len elements within a given array from src_index index to dst_index
922 void MoveElements(FixedArray* array, int dst_index, int src_index, int len);
924 // Make a copy of src and return it. Returns
925 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
926 MUST_USE_RESULT inline MaybeObject* CopyFixedArray(FixedArray* src);
928 // Make a copy of src, set the map, and return the copy. Returns
929 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
930 MUST_USE_RESULT MaybeObject* CopyFixedArrayWithMap(FixedArray* src, Map* map);
932 // Make a copy of src and return it. Returns
933 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
934 MUST_USE_RESULT inline MaybeObject* CopyFixedDoubleArray(
935 FixedDoubleArray* src);
937 // Make a copy of src, set the map, and return the copy. Returns
938 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
939 MUST_USE_RESULT MaybeObject* CopyFixedDoubleArrayWithMap(
940 FixedDoubleArray* src, Map* map);
942 // Make a copy of src and return it. Returns
943 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
944 MUST_USE_RESULT inline MaybeObject* CopyConstantPoolArray(
945 ConstantPoolArray* src);
947 // Make a copy of src, set the map, and return the copy. Returns
948 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
949 MUST_USE_RESULT MaybeObject* CopyConstantPoolArrayWithMap(
950 ConstantPoolArray* src, Map* map);
952 // Allocates a fixed array initialized with the hole values.
953 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
955 // Please note this does not perform a garbage collection.
956 MUST_USE_RESULT MaybeObject* AllocateFixedArrayWithHoles(
958 PretenureFlag pretenure = NOT_TENURED);
960 MUST_USE_RESULT MaybeObject* AllocateConstantPoolArray(
961 int first_int64_index,
963 int first_int32_index);
965 // Allocates a fixed double array with uninitialized values. Returns
966 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
967 // Please note this does not perform a garbage collection.
968 MUST_USE_RESULT MaybeObject* AllocateUninitializedFixedDoubleArray(
970 PretenureFlag pretenure = NOT_TENURED);
972 // Allocates a fixed double array with hole values. Returns
973 // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
974 // Please note this does not perform a garbage collection.
975 MUST_USE_RESULT MaybeObject* AllocateFixedDoubleArrayWithHoles(
977 PretenureFlag pretenure = NOT_TENURED);
979 // AllocateHashTable is identical to AllocateFixedArray except
980 // that the resulting object has hash_table_map as map.
981 MUST_USE_RESULT MaybeObject* AllocateHashTable(
982 int length, PretenureFlag pretenure = NOT_TENURED);
984 // Allocate a native (but otherwise uninitialized) context.
985 MUST_USE_RESULT MaybeObject* AllocateNativeContext();
987 // Allocate a global context.
988 MUST_USE_RESULT MaybeObject* AllocateGlobalContext(JSFunction* function,
989 ScopeInfo* scope_info);
991 // Allocate a module context.
992 MUST_USE_RESULT MaybeObject* AllocateModuleContext(ScopeInfo* scope_info);
994 // Allocate a function context.
995 MUST_USE_RESULT MaybeObject* AllocateFunctionContext(int length,
996 JSFunction* function);
998 // Allocate a catch context.
999 MUST_USE_RESULT MaybeObject* AllocateCatchContext(JSFunction* function,
1002 Object* thrown_object);
1003 // Allocate a 'with' context.
1004 MUST_USE_RESULT MaybeObject* AllocateWithContext(JSFunction* function,
1006 JSReceiver* extension);
1008 // Allocate a block context.
1009 MUST_USE_RESULT MaybeObject* AllocateBlockContext(JSFunction* function,
1013 // Allocates a new utility object in the old generation.
1014 MUST_USE_RESULT MaybeObject* AllocateStruct(InstanceType type);
1016 // Allocates a function initialized with a shared part.
1017 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1019 // Please note this does not perform a garbage collection.
1020 MUST_USE_RESULT MaybeObject* AllocateFunction(
1022 SharedFunctionInfo* shared,
1024 PretenureFlag pretenure = TENURED);
1026 // Arguments object size.
1027 static const int kArgumentsObjectSize =
1028 JSObject::kHeaderSize + 2 * kPointerSize;
1029 // Strict mode arguments has no callee so it is smaller.
1030 static const int kArgumentsObjectSizeStrict =
1031 JSObject::kHeaderSize + 1 * kPointerSize;
1032 // Indicies for direct access into argument objects.
1033 static const int kArgumentsLengthIndex = 0;
1034 // callee is only valid in non-strict mode.
1035 static const int kArgumentsCalleeIndex = 1;
1037 // Allocates an arguments object - optionally with an elements array.
1038 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1040 // Please note this does not perform a garbage collection.
1041 MUST_USE_RESULT MaybeObject* AllocateArgumentsObject(
1042 Object* callee, int length);
1044 // Same as NewNumberFromDouble, but may return a preallocated/immutable
1045 // number object (e.g., minus_zero_value_, nan_value_)
1046 MUST_USE_RESULT MaybeObject* NumberFromDouble(
1047 double value, PretenureFlag pretenure = NOT_TENURED);
1049 // Allocated a HeapNumber from value.
1050 MUST_USE_RESULT MaybeObject* AllocateHeapNumber(
1051 double value, PretenureFlag pretenure = NOT_TENURED);
1053 // Converts an int into either a Smi or a HeapNumber object.
1054 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1056 // Please note this does not perform a garbage collection.
1057 MUST_USE_RESULT inline MaybeObject* NumberFromInt32(
1058 int32_t value, PretenureFlag pretenure = NOT_TENURED);
1060 // Converts an int into either a Smi or a HeapNumber object.
1061 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1063 // Please note this does not perform a garbage collection.
1064 MUST_USE_RESULT inline MaybeObject* NumberFromUint32(
1065 uint32_t value, PretenureFlag pretenure = NOT_TENURED);
1067 // Allocates a new foreign object.
1068 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1070 // Please note this does not perform a garbage collection.
1071 MUST_USE_RESULT MaybeObject* AllocateForeign(
1072 Address address, PretenureFlag pretenure = NOT_TENURED);
1074 // Allocates a new SharedFunctionInfo object.
1075 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1077 // Please note this does not perform a garbage collection.
1078 MUST_USE_RESULT MaybeObject* AllocateSharedFunctionInfo(Object* name);
1080 // Allocates a new JSMessageObject object.
1081 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1083 // Please note that this does not perform a garbage collection.
1084 MUST_USE_RESULT MaybeObject* AllocateJSMessageObject(
1090 Object* stack_trace,
1091 Object* stack_frames);
1093 // Allocate a new external string object, which is backed by a string
1094 // resource that resides outside the V8 heap.
1095 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1097 // Please note this does not perform a garbage collection.
1098 MUST_USE_RESULT MaybeObject* AllocateExternalStringFromAscii(
1099 const ExternalAsciiString::Resource* resource);
1100 MUST_USE_RESULT MaybeObject* AllocateExternalStringFromTwoByte(
1101 const ExternalTwoByteString::Resource* resource);
1103 // Finalizes an external string by deleting the associated external
1104 // data and clearing the resource pointer.
1105 inline void FinalizeExternalString(String* string);
1107 // Allocates an uninitialized object. The memory is non-executable if the
1108 // hardware and OS allow.
1109 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1111 // Please note this function does not perform a garbage collection.
1112 MUST_USE_RESULT inline MaybeObject* AllocateRaw(int size_in_bytes,
1113 AllocationSpace space,
1114 AllocationSpace retry_space);
1116 // Initialize a filler object to keep the ability to iterate over the heap
1117 // when shortening objects.
1118 void CreateFillerObjectAt(Address addr, int size);
1120 // Makes a new native code object
1121 // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
1122 // failed. On success, the pointer to the Code object is stored in the
1123 // self_reference. This allows generated code to reference its own Code
1124 // object by containing this pointer.
1125 // Please note this function does not perform a garbage collection.
1126 MUST_USE_RESULT MaybeObject* CreateCode(
1127 const CodeDesc& desc,
1129 Handle<Object> self_reference,
1130 bool immovable = false,
1131 bool crankshafted = false,
1132 int prologue_offset = Code::kPrologueOffsetNotSet);
1134 MUST_USE_RESULT MaybeObject* CopyCode(Code* code);
1136 // Copy the code and scope info part of the code object, but insert
1137 // the provided data as the relocation information.
1138 MUST_USE_RESULT MaybeObject* CopyCode(Code* code, Vector<byte> reloc_info);
1140 // Finds the internalized copy for string in the string table.
1141 // If not found, a new string is added to the table and returned.
1142 // Returns Failure::RetryAfterGC(requested_bytes, space) if allocation
1144 // Please note this function does not perform a garbage collection.
1145 MUST_USE_RESULT MaybeObject* InternalizeUtf8String(const char* str) {
1146 return InternalizeUtf8String(CStrVector(str));
1148 MUST_USE_RESULT MaybeObject* InternalizeUtf8String(Vector<const char> str);
1150 MUST_USE_RESULT MaybeObject* InternalizeString(String* str);
1151 MUST_USE_RESULT MaybeObject* InternalizeStringWithKey(HashTableKey* key);
1153 bool InternalizeStringIfExists(String* str, String** result);
1154 bool InternalizeTwoCharsStringIfExists(String* str, String** result);
1156 // Compute the matching internalized string map for a string if possible.
1157 // NULL is returned if string is in new space or not flattened.
1158 Map* InternalizedStringMapForString(String* str);
1160 // Tries to flatten a string before compare operation.
1162 // Returns a failure in case it was decided that flattening was
1163 // necessary and failed. Note, if flattening is not necessary the
1164 // string might stay non-flat even when not a failure is returned.
1166 // Please note this function does not perform a garbage collection.
1167 MUST_USE_RESULT inline MaybeObject* PrepareForCompare(String* str);
1169 // Converts the given boolean condition to JavaScript boolean value.
1170 inline Object* ToBoolean(bool condition);
1172 // Performs garbage collection operation.
1173 // Returns whether there is a chance that another major GC could
1174 // collect more garbage.
1175 inline bool CollectGarbage(
1176 AllocationSpace space,
1177 const char* gc_reason = NULL,
1178 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
1180 static const int kNoGCFlags = 0;
1181 static const int kSweepPreciselyMask = 1;
1182 static const int kReduceMemoryFootprintMask = 2;
1183 static const int kAbortIncrementalMarkingMask = 4;
1185 // Making the heap iterable requires us to sweep precisely and abort any
1186 // incremental marking as well.
1187 static const int kMakeHeapIterableMask =
1188 kSweepPreciselyMask | kAbortIncrementalMarkingMask;
1190 // Performs a full garbage collection. If (flags & kMakeHeapIterableMask) is
1191 // non-zero, then the slower precise sweeper is used, which leaves the heap
1192 // in a state where we can iterate over the heap visiting all objects.
1193 void CollectAllGarbage(
1195 const char* gc_reason = NULL,
1196 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
1198 // Last hope GC, should try to squeeze as much as possible.
1199 void CollectAllAvailableGarbage(const char* gc_reason = NULL);
1201 // Check whether the heap is currently iterable.
1202 bool IsHeapIterable();
1204 // Ensure that we have swept all spaces in such a way that we can iterate
1205 // over all objects. May cause a GC.
1206 void EnsureHeapIsIterable();
1208 // Notify the heap that a context has been disposed.
1209 int NotifyContextDisposed();
1211 // Utility to invoke the scavenger. This is needed in test code to
1212 // ensure correct callback for weak global handles.
1213 void PerformScavenge();
1215 inline void increment_scan_on_scavenge_pages() {
1216 scan_on_scavenge_pages_++;
1217 if (FLAG_gc_verbose) {
1218 PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
1222 inline void decrement_scan_on_scavenge_pages() {
1223 scan_on_scavenge_pages_--;
1224 if (FLAG_gc_verbose) {
1225 PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
1229 PromotionQueue* promotion_queue() { return &promotion_queue_; }
1232 // Utility used with flag gc-greedy.
1233 void GarbageCollectionGreedyCheck();
1236 void AddGCPrologueCallback(v8::Isolate::GCPrologueCallback callback,
1237 GCType gc_type_filter,
1238 bool pass_isolate = true);
1239 void RemoveGCPrologueCallback(v8::Isolate::GCPrologueCallback callback);
1241 void AddGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback,
1242 GCType gc_type_filter,
1243 bool pass_isolate = true);
1244 void RemoveGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback);
1246 // Heap root getters. We have versions with and without type::cast() here.
1247 // You can't use type::cast during GC because the assert fails.
1248 // TODO(1490): Try removing the unchecked accessors, now that GC marking does
1249 // not corrupt the map.
1250 #define ROOT_ACCESSOR(type, name, camel_name) \
1252 return type::cast(roots_[k##camel_name##RootIndex]); \
1254 type* raw_unchecked_##name() { \
1255 return reinterpret_cast<type*>(roots_[k##camel_name##RootIndex]); \
1257 ROOT_LIST(ROOT_ACCESSOR)
1258 #undef ROOT_ACCESSOR
1260 // Utility type maps
1261 #define STRUCT_MAP_ACCESSOR(NAME, Name, name) \
1262 Map* name##_map() { \
1263 return Map::cast(roots_[k##Name##MapRootIndex]); \
1265 STRUCT_LIST(STRUCT_MAP_ACCESSOR)
1266 #undef STRUCT_MAP_ACCESSOR
1268 #define STRING_ACCESSOR(name, str) String* name() { \
1269 return String::cast(roots_[k##name##RootIndex]); \
1271 INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
1272 #undef STRING_ACCESSOR
1274 // The hidden_string is special because it is the empty string, but does
1275 // not match the empty string.
1276 String* hidden_string() { return hidden_string_; }
1278 void set_native_contexts_list(Object* object) {
1279 native_contexts_list_ = object;
1281 Object* native_contexts_list() { return native_contexts_list_; }
1283 void set_array_buffers_list(Object* object) {
1284 array_buffers_list_ = object;
1286 Object* array_buffers_list() { return array_buffers_list_; }
1288 void set_allocation_sites_list(Object* object) {
1289 allocation_sites_list_ = object;
1291 Object* allocation_sites_list() { return allocation_sites_list_; }
1292 Object** allocation_sites_list_address() { return &allocation_sites_list_; }
1294 Object* weak_object_to_code_table() { return weak_object_to_code_table_; }
1296 // Number of mark-sweeps.
1297 unsigned int ms_count() { return ms_count_; }
1299 // Iterates over all roots in the heap.
1300 void IterateRoots(ObjectVisitor* v, VisitMode mode);
1301 // Iterates over all strong roots in the heap.
1302 void IterateStrongRoots(ObjectVisitor* v, VisitMode mode);
1303 // Iterates over all the other roots in the heap.
1304 void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
1306 // Iterate pointers to from semispace of new space found in memory interval
1307 // from start to end.
1308 void IterateAndMarkPointersToFromSpace(Address start,
1310 ObjectSlotCallback callback);
1312 // Returns whether the object resides in new space.
1313 inline bool InNewSpace(Object* object);
1314 inline bool InNewSpace(Address address);
1315 inline bool InNewSpacePage(Address address);
1316 inline bool InFromSpace(Object* object);
1317 inline bool InToSpace(Object* object);
1319 // Returns whether the object resides in old pointer space.
1320 inline bool InOldPointerSpace(Address address);
1321 inline bool InOldPointerSpace(Object* object);
1323 // Returns whether the object resides in old data space.
1324 inline bool InOldDataSpace(Address address);
1325 inline bool InOldDataSpace(Object* object);
1327 // Checks whether an address/object in the heap (including auxiliary
1328 // area and unused area).
1329 bool Contains(Address addr);
1330 bool Contains(HeapObject* value);
1332 // Checks whether an address/object in a space.
1333 // Currently used by tests, serialization and heap verification only.
1334 bool InSpace(Address addr, AllocationSpace space);
1335 bool InSpace(HeapObject* value, AllocationSpace space);
1337 // Finds out which space an object should get promoted to based on its type.
1338 inline OldSpace* TargetSpace(HeapObject* object);
1339 static inline AllocationSpace TargetSpaceId(InstanceType type);
1341 // Checks whether the given object is allowed to be migrated from it's
1342 // current space into the given destination space. Used for debugging.
1343 inline bool AllowedToBeMigrated(HeapObject* object, AllocationSpace dest);
1345 // Sets the stub_cache_ (only used when expanding the dictionary).
1346 void public_set_code_stubs(UnseededNumberDictionary* value) {
1347 roots_[kCodeStubsRootIndex] = value;
1350 // Support for computing object sizes for old objects during GCs. Returns
1351 // a function that is guaranteed to be safe for computing object sizes in
1352 // the current GC phase.
1353 HeapObjectCallback GcSafeSizeOfOldObjectFunction() {
1354 return gc_safe_size_of_old_object_;
1357 // Sets the non_monomorphic_cache_ (only used when expanding the dictionary).
1358 void public_set_non_monomorphic_cache(UnseededNumberDictionary* value) {
1359 roots_[kNonMonomorphicCacheRootIndex] = value;
1362 void public_set_empty_script(Script* script) {
1363 roots_[kEmptyScriptRootIndex] = script;
1366 void public_set_store_buffer_top(Address* top) {
1367 roots_[kStoreBufferTopRootIndex] = reinterpret_cast<Smi*>(top);
1370 // Generated code can embed this address to get access to the roots.
1371 Object** roots_array_start() { return roots_; }
1373 Address* store_buffer_top_address() {
1374 return reinterpret_cast<Address*>(&roots_[kStoreBufferTopRootIndex]);
1377 // Get address of native contexts list for serialization support.
1378 Object** native_contexts_list_address() {
1379 return &native_contexts_list_;
1383 // Verify the heap is in its normal state before or after a GC.
1387 bool weak_embedded_objects_verification_enabled() {
1388 return no_weak_object_verification_scope_depth_ == 0;
1394 void PrintHandles();
1396 void OldPointerSpaceCheckStoreBuffer();
1397 void MapSpaceCheckStoreBuffer();
1398 void LargeObjectSpaceCheckStoreBuffer();
1400 // Report heap statistics.
1401 void ReportHeapStatistics(const char* title);
1402 void ReportCodeStatistics(const char* title);
1405 // Zapping is needed for verify heap, and always done in debug builds.
1406 static inline bool ShouldZapGarbage() {
1411 return FLAG_verify_heap;
1418 // Print short heap statistics.
1419 void PrintShortHeapStatistics();
1421 // Write barrier support for address[offset] = o.
1422 INLINE(void RecordWrite(Address address, int offset));
1424 // Write barrier support for address[start : start + len[ = o.
1425 INLINE(void RecordWrites(Address address, int start, int len));
1427 enum HeapState { NOT_IN_GC, SCAVENGE, MARK_COMPACT };
1428 inline HeapState gc_state() { return gc_state_; }
1430 inline bool IsInGCPostProcessing() { return gc_post_processing_depth_ > 0; }
1433 void set_allocation_timeout(int timeout) {
1434 allocation_timeout_ = timeout;
1437 bool disallow_allocation_failure() {
1438 return disallow_allocation_failure_;
1441 void TracePathToObjectFrom(Object* target, Object* root);
1442 void TracePathToObject(Object* target);
1443 void TracePathToGlobal();
1446 // Callback function passed to Heap::Iterate etc. Copies an object if
1447 // necessary, the object might be promoted to an old space. The caller must
1448 // ensure the precondition that the object is (a) a heap object and (b) in
1449 // the heap's from space.
1450 static inline void ScavengePointer(HeapObject** p);
1451 static inline void ScavengeObject(HeapObject** p, HeapObject* object);
1453 // An object may have an AllocationSite associated with it through a trailing
1454 // AllocationMemento. Its feedback should be updated when objects are found
1456 static inline void UpdateAllocationSiteFeedback(HeapObject* object);
1458 // Support for partial snapshots. After calling this we have a linear
1459 // space to write objects in each space.
1460 void ReserveSpace(int *sizes, Address* addresses);
1463 // Support for the API.
1466 bool CreateApiObjects();
1468 // Attempt to find the number in a small cache. If we finds it, return
1469 // the string representation of the number. Otherwise return undefined.
1470 Object* GetNumberStringCache(Object* number);
1472 // Update the cache with a new number-string pair.
1473 void SetNumberStringCache(Object* number, String* str);
1475 // Adjusts the amount of registered external memory.
1476 // Returns the adjusted value.
1477 inline int64_t AdjustAmountOfExternalAllocatedMemory(
1478 int64_t change_in_bytes);
1480 // This is only needed for testing high promotion mode.
1481 void SetNewSpaceHighPromotionModeActive(bool mode) {
1482 new_space_high_promotion_mode_active_ = mode;
1485 // Returns the allocation mode (pre-tenuring) based on observed promotion
1486 // rates of previous collections.
1487 inline PretenureFlag GetPretenureMode() {
1488 return FLAG_pretenuring && new_space_high_promotion_mode_active_
1489 ? TENURED : NOT_TENURED;
1492 inline Address* NewSpaceHighPromotionModeActiveAddress() {
1493 return reinterpret_cast<Address*>(&new_space_high_promotion_mode_active_);
1496 inline intptr_t PromotedTotalSize() {
1497 int64_t total = PromotedSpaceSizeOfObjects() + PromotedExternalMemorySize();
1498 if (total > kMaxInt) return static_cast<intptr_t>(kMaxInt);
1499 if (total < 0) return 0;
1500 return static_cast<intptr_t>(total);
1503 inline intptr_t OldGenerationSpaceAvailable() {
1504 return old_generation_allocation_limit_ - PromotedTotalSize();
1507 inline intptr_t OldGenerationCapacityAvailable() {
1508 return max_old_generation_size_ - PromotedTotalSize();
1511 static const intptr_t kMinimumOldGenerationAllocationLimit =
1512 8 * (Page::kPageSize > MB ? Page::kPageSize : MB);
1514 intptr_t OldGenerationAllocationLimit(intptr_t old_gen_size) {
1515 const int divisor = FLAG_stress_compaction ? 10 :
1516 new_space_high_promotion_mode_active_ ? 1 : 3;
1518 Max(old_gen_size + old_gen_size / divisor,
1519 kMinimumOldGenerationAllocationLimit);
1520 limit += new_space_.Capacity();
1521 // TODO(hpayer): Can be removed when when pretenuring is supported for all
1522 // allocation sites.
1523 if (IsHighSurvivalRate() && IsStableOrIncreasingSurvivalTrend()) {
1526 intptr_t halfway_to_the_max = (old_gen_size + max_old_generation_size_) / 2;
1527 return Min(limit, halfway_to_the_max);
1530 // Indicates whether inline bump-pointer allocation has been disabled.
1531 bool inline_allocation_disabled() { return inline_allocation_disabled_; }
1533 // Switch whether inline bump-pointer allocation should be used.
1534 void EnableInlineAllocation();
1535 void DisableInlineAllocation();
1537 // Implements the corresponding V8 API function.
1538 bool IdleNotification(int hint);
1540 // Declare all the root indices.
1541 enum RootListIndex {
1542 #define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
1543 STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
1544 #undef ROOT_INDEX_DECLARATION
1546 #define STRING_INDEX_DECLARATION(name, str) k##name##RootIndex,
1547 INTERNALIZED_STRING_LIST(STRING_INDEX_DECLARATION)
1548 #undef STRING_DECLARATION
1550 // Utility type maps
1551 #define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
1552 STRUCT_LIST(DECLARE_STRUCT_MAP)
1553 #undef DECLARE_STRUCT_MAP
1555 kStringTableRootIndex,
1556 kStrongRootListLength = kStringTableRootIndex,
1560 STATIC_CHECK(kUndefinedValueRootIndex == Internals::kUndefinedValueRootIndex);
1561 STATIC_CHECK(kNullValueRootIndex == Internals::kNullValueRootIndex);
1562 STATIC_CHECK(kTrueValueRootIndex == Internals::kTrueValueRootIndex);
1563 STATIC_CHECK(kFalseValueRootIndex == Internals::kFalseValueRootIndex);
1564 STATIC_CHECK(kempty_stringRootIndex == Internals::kEmptyStringRootIndex);
1566 // Generated code can embed direct references to non-writable roots if
1567 // they are in new space.
1568 static bool RootCanBeWrittenAfterInitialization(RootListIndex root_index);
1569 // Generated code can treat direct references to this root as constant.
1570 bool RootCanBeTreatedAsConstant(RootListIndex root_index);
1572 MUST_USE_RESULT MaybeObject* NumberToString(
1573 Object* number, bool check_number_string_cache = true);
1574 MUST_USE_RESULT MaybeObject* Uint32ToString(
1575 uint32_t value, bool check_number_string_cache = true);
1577 Map* MapForFixedTypedArray(ExternalArrayType array_type);
1578 RootListIndex RootIndexForFixedTypedArray(
1579 ExternalArrayType array_type);
1581 Map* MapForExternalArrayType(ExternalArrayType array_type);
1582 RootListIndex RootIndexForExternalArrayType(
1583 ExternalArrayType array_type);
1585 RootListIndex RootIndexForEmptyExternalArray(ElementsKind kind);
1586 ExternalArray* EmptyExternalArrayForMap(Map* map);
1588 void RecordStats(HeapStats* stats, bool take_snapshot = false);
1590 // Copy block of memory from src to dst. Size of block should be aligned
1592 static inline void CopyBlock(Address dst, Address src, int byte_size);
1594 // Optimized version of memmove for blocks with pointer size aligned sizes and
1595 // pointer size aligned addresses.
1596 static inline void MoveBlock(Address dst, Address src, int byte_size);
1598 // Check new space expansion criteria and expand semispaces if it was hit.
1599 void CheckNewSpaceExpansionCriteria();
1601 inline void IncrementYoungSurvivorsCounter(int survived) {
1602 ASSERT(survived >= 0);
1603 young_survivors_after_last_gc_ = survived;
1604 survived_since_last_expansion_ += survived;
1607 inline bool NextGCIsLikelyToBeFull() {
1608 if (FLAG_gc_global) return true;
1610 if (FLAG_stress_compaction && (gc_count_ & 1) != 0) return true;
1612 intptr_t adjusted_allocation_limit =
1613 old_generation_allocation_limit_ - new_space_.Capacity();
1615 if (PromotedTotalSize() >= adjusted_allocation_limit) return true;
1620 void UpdateNewSpaceReferencesInExternalStringTable(
1621 ExternalStringTableUpdaterCallback updater_func);
1623 void UpdateReferencesInExternalStringTable(
1624 ExternalStringTableUpdaterCallback updater_func);
1626 void ProcessWeakReferences(WeakObjectRetainer* retainer);
1628 void VisitExternalResources(v8::ExternalResourceVisitor* visitor);
1630 // Helper function that governs the promotion policy from new space to
1631 // old. If the object's old address lies below the new space's age
1632 // mark or if we've already filled the bottom 1/16th of the to space,
1633 // we try to promote this object.
1634 inline bool ShouldBePromoted(Address old_address, int object_size);
1636 void ClearJSFunctionResultCaches();
1638 void ClearNormalizedMapCaches();
1640 GCTracer* tracer() { return tracer_; }
1642 // Returns the size of objects residing in non new spaces.
1643 intptr_t PromotedSpaceSizeOfObjects();
1645 double total_regexp_code_generated() { return total_regexp_code_generated_; }
1646 void IncreaseTotalRegexpCodeGenerated(int size) {
1647 total_regexp_code_generated_ += size;
1650 void IncrementCodeGeneratedBytes(bool is_crankshafted, int size) {
1651 if (is_crankshafted) {
1652 crankshaft_codegen_bytes_generated_ += size;
1654 full_codegen_bytes_generated_ += size;
1658 // Returns maximum GC pause.
1659 double get_max_gc_pause() { return max_gc_pause_; }
1661 // Returns maximum size of objects alive after GC.
1662 intptr_t get_max_alive_after_gc() { return max_alive_after_gc_; }
1664 // Returns minimal interval between two subsequent collections.
1665 double get_min_in_mutator() { return min_in_mutator_; }
1667 // TODO(hpayer): remove, should be handled by GCTracer
1668 void AddMarkingTime(double marking_time) {
1669 marking_time_ += marking_time;
1672 double marking_time() const {
1673 return marking_time_;
1676 // TODO(hpayer): remove, should be handled by GCTracer
1677 void AddSweepingTime(double sweeping_time) {
1678 sweeping_time_ += sweeping_time;
1681 double sweeping_time() const {
1682 return sweeping_time_;
1685 MarkCompactCollector* mark_compact_collector() {
1686 return &mark_compact_collector_;
1689 StoreBuffer* store_buffer() {
1690 return &store_buffer_;
1693 Marking* marking() {
1697 IncrementalMarking* incremental_marking() {
1698 return &incremental_marking_;
1701 bool IsSweepingComplete() {
1702 return !mark_compact_collector()->IsConcurrentSweepingInProgress() &&
1703 old_data_space()->IsLazySweepingComplete() &&
1704 old_pointer_space()->IsLazySweepingComplete();
1707 bool AdvanceSweepers(int step_size);
1709 bool EnsureSweepersProgressed(int step_size) {
1710 bool sweeping_complete = old_data_space()->EnsureSweeperProgress(step_size);
1711 sweeping_complete &= old_pointer_space()->EnsureSweeperProgress(step_size);
1712 return sweeping_complete;
1715 ExternalStringTable* external_string_table() {
1716 return &external_string_table_;
1719 // Returns the current sweep generation.
1720 int sweep_generation() {
1721 return sweep_generation_;
1724 inline Isolate* isolate();
1726 void CallGCPrologueCallbacks(GCType gc_type, GCCallbackFlags flags);
1727 void CallGCEpilogueCallbacks(GCType gc_type, GCCallbackFlags flags);
1729 inline bool OldGenerationAllocationLimitReached();
1731 inline void DoScavengeObject(Map* map, HeapObject** slot, HeapObject* obj) {
1732 scavenging_visitors_table_.GetVisitor(map)(map, slot, obj);
1735 void QueueMemoryChunkForFree(MemoryChunk* chunk);
1736 void FreeQueuedChunks();
1738 int gc_count() const { return gc_count_; }
1740 // Completely clear the Instanceof cache (to stop it keeping objects alive
1742 inline void CompletelyClearInstanceofCache();
1744 // The roots that have an index less than this are always in old space.
1745 static const int kOldSpaceRoots = 0x20;
1747 uint32_t HashSeed() {
1748 uint32_t seed = static_cast<uint32_t>(hash_seed()->value());
1749 ASSERT(FLAG_randomize_hashes || seed == 0);
1753 void SetArgumentsAdaptorDeoptPCOffset(int pc_offset) {
1754 ASSERT(arguments_adaptor_deopt_pc_offset() == Smi::FromInt(0));
1755 set_arguments_adaptor_deopt_pc_offset(Smi::FromInt(pc_offset));
1758 void SetConstructStubDeoptPCOffset(int pc_offset) {
1759 ASSERT(construct_stub_deopt_pc_offset() == Smi::FromInt(0));
1760 set_construct_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
1763 void SetGetterStubDeoptPCOffset(int pc_offset) {
1764 ASSERT(getter_stub_deopt_pc_offset() == Smi::FromInt(0));
1765 set_getter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
1768 void SetSetterStubDeoptPCOffset(int pc_offset) {
1769 ASSERT(setter_stub_deopt_pc_offset() == Smi::FromInt(0));
1770 set_setter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
1773 // For post mortem debugging.
1774 void RememberUnmappedPage(Address page, bool compacted);
1776 // Global inline caching age: it is incremented on some GCs after context
1777 // disposal. We use it to flush inline caches.
1778 int global_ic_age() {
1779 return global_ic_age_;
1782 void AgeInlineCaches() {
1783 global_ic_age_ = (global_ic_age_ + 1) & SharedFunctionInfo::ICAgeBits::kMax;
1786 bool flush_monomorphic_ics() { return flush_monomorphic_ics_; }
1788 int64_t amount_of_external_allocated_memory() {
1789 return amount_of_external_allocated_memory_;
1792 // ObjectStats are kept in two arrays, counts and sizes. Related stats are
1793 // stored in a contiguous linear buffer. Stats groups are stored one after
1796 FIRST_CODE_KIND_SUB_TYPE = LAST_TYPE + 1,
1797 FIRST_FIXED_ARRAY_SUB_TYPE =
1798 FIRST_CODE_KIND_SUB_TYPE + Code::NUMBER_OF_KINDS,
1799 FIRST_CODE_AGE_SUB_TYPE =
1800 FIRST_FIXED_ARRAY_SUB_TYPE + LAST_FIXED_ARRAY_SUB_TYPE + 1,
1801 OBJECT_STATS_COUNT = FIRST_CODE_AGE_SUB_TYPE + Code::kCodeAgeCount + 1
1804 void RecordObjectStats(InstanceType type, size_t size) {
1805 ASSERT(type <= LAST_TYPE);
1806 object_counts_[type]++;
1807 object_sizes_[type] += size;
1810 void RecordCodeSubTypeStats(int code_sub_type, int code_age, size_t size) {
1811 int code_sub_type_index = FIRST_CODE_KIND_SUB_TYPE + code_sub_type;
1812 int code_age_index =
1813 FIRST_CODE_AGE_SUB_TYPE + code_age - Code::kFirstCodeAge;
1814 ASSERT(code_sub_type_index >= FIRST_CODE_KIND_SUB_TYPE &&
1815 code_sub_type_index < FIRST_CODE_AGE_SUB_TYPE);
1816 ASSERT(code_age_index >= FIRST_CODE_AGE_SUB_TYPE &&
1817 code_age_index < OBJECT_STATS_COUNT);
1818 object_counts_[code_sub_type_index]++;
1819 object_sizes_[code_sub_type_index] += size;
1820 object_counts_[code_age_index]++;
1821 object_sizes_[code_age_index] += size;
1824 void RecordFixedArraySubTypeStats(int array_sub_type, size_t size) {
1825 ASSERT(array_sub_type <= LAST_FIXED_ARRAY_SUB_TYPE);
1826 object_counts_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type]++;
1827 object_sizes_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type] += size;
1830 void CheckpointObjectStats();
1832 // We don't use a LockGuard here since we want to lock the heap
1833 // only when FLAG_concurrent_recompilation is true.
1834 class RelocationLock {
1836 explicit RelocationLock(Heap* heap) : heap_(heap) {
1837 if (FLAG_concurrent_recompilation) {
1838 heap_->relocation_mutex_->Lock();
1844 if (FLAG_concurrent_recompilation) {
1845 heap_->relocation_mutex_->Unlock();
1853 MaybeObject* AddWeakObjectToCodeDependency(Object* obj, DependentCode* dep);
1855 DependentCode* LookupWeakObjectToCodeDependency(Object* obj);
1857 void InitializeWeakObjectToCodeTable() {
1858 set_weak_object_to_code_table(undefined_value());
1861 void EnsureWeakObjectToCodeTable();
1863 static void FatalProcessOutOfMemory(const char* location,
1864 bool take_snapshot = false);
1869 // This can be calculated directly from a pointer to the heap; however, it is
1870 // more expedient to get at the isolate directly from within Heap methods.
1873 Object* roots_[kRootListLength];
1875 intptr_t code_range_size_;
1876 int reserved_semispace_size_;
1877 int max_semispace_size_;
1878 int initial_semispace_size_;
1879 intptr_t max_old_generation_size_;
1880 intptr_t max_executable_size_;
1881 intptr_t maximum_committed_;
1883 // For keeping track of how much data has survived
1884 // scavenge since last new space expansion.
1885 int survived_since_last_expansion_;
1887 // For keeping track on when to flush RegExp code.
1888 int sweep_generation_;
1890 int always_allocate_scope_depth_;
1891 int linear_allocation_scope_depth_;
1893 // For keeping track of context disposals.
1894 int contexts_disposed_;
1898 bool flush_monomorphic_ics_;
1900 int scan_on_scavenge_pages_;
1902 NewSpace new_space_;
1903 OldSpace* old_pointer_space_;
1904 OldSpace* old_data_space_;
1905 OldSpace* code_space_;
1906 MapSpace* map_space_;
1907 CellSpace* cell_space_;
1908 PropertyCellSpace* property_cell_space_;
1909 LargeObjectSpace* lo_space_;
1910 HeapState gc_state_;
1911 int gc_post_processing_depth_;
1913 // Returns the amount of external memory registered since last global gc.
1914 int64_t PromotedExternalMemorySize();
1916 unsigned int ms_count_; // how many mark-sweep collections happened
1917 unsigned int gc_count_; // how many gc happened
1919 // For post mortem debugging.
1920 static const int kRememberedUnmappedPages = 128;
1921 int remembered_unmapped_pages_index_;
1922 Address remembered_unmapped_pages_[kRememberedUnmappedPages];
1924 // Total length of the strings we failed to flatten since the last GC.
1925 int unflattened_strings_length_;
1927 #define ROOT_ACCESSOR(type, name, camel_name) \
1928 inline void set_##name(type* value) { \
1929 /* The deserializer makes use of the fact that these common roots are */ \
1930 /* never in new space and never on a page that is being compacted. */ \
1931 ASSERT(k##camel_name##RootIndex >= kOldSpaceRoots || !InNewSpace(value)); \
1932 roots_[k##camel_name##RootIndex] = value; \
1934 ROOT_LIST(ROOT_ACCESSOR)
1935 #undef ROOT_ACCESSOR
1938 // If the --gc-interval flag is set to a positive value, this
1939 // variable holds the value indicating the number of allocations
1940 // remain until the next failure and garbage collection.
1941 int allocation_timeout_;
1943 // Do we expect to be able to handle allocation failure at this
1945 bool disallow_allocation_failure_;
1948 // Indicates that the new space should be kept small due to high promotion
1949 // rates caused by the mutator allocating a lot of long-lived objects.
1950 // TODO(hpayer): change to bool if no longer accessed from generated code
1951 intptr_t new_space_high_promotion_mode_active_;
1953 // Limit that triggers a global GC on the next (normally caused) GC. This
1954 // is checked when we have already decided to do a GC to help determine
1955 // which collector to invoke, before expanding a paged space in the old
1956 // generation and on every allocation in large object space.
1957 intptr_t old_generation_allocation_limit_;
1959 // Used to adjust the limits that control the timing of the next GC.
1960 intptr_t size_of_old_gen_at_last_old_space_gc_;
1962 // Limit on the amount of externally allocated memory allowed
1963 // between global GCs. If reached a global GC is forced.
1964 intptr_t external_allocation_limit_;
1966 // The amount of external memory registered through the API kept alive
1967 // by global handles
1968 int64_t amount_of_external_allocated_memory_;
1970 // Caches the amount of external memory registered at the last global gc.
1971 int64_t amount_of_external_allocated_memory_at_last_global_gc_;
1973 // Indicates that an allocation has failed in the old generation since the
1975 bool old_gen_exhausted_;
1977 // Indicates that inline bump-pointer allocation has been globally disabled
1978 // for all spaces. This is used to disable allocations in generated code.
1979 bool inline_allocation_disabled_;
1981 // Weak list heads, threaded through the objects.
1982 // List heads are initilized lazily and contain the undefined_value at start.
1983 Object* native_contexts_list_;
1984 Object* array_buffers_list_;
1985 Object* allocation_sites_list_;
1987 // WeakHashTable that maps objects embedded in optimized code to dependent
1988 // code list. It is initilized lazily and contains the undefined_value at
1990 Object* weak_object_to_code_table_;
1992 StoreBufferRebuilder store_buffer_rebuilder_;
1994 struct StringTypeTable {
1997 RootListIndex index;
2000 struct ConstantStringTable {
2001 const char* contents;
2002 RootListIndex index;
2005 struct StructTable {
2008 RootListIndex index;
2011 static const StringTypeTable string_type_table[];
2012 static const ConstantStringTable constant_string_table[];
2013 static const StructTable struct_table[];
2015 // The special hidden string which is an empty string, but does not match
2016 // any string when looked up in properties.
2017 String* hidden_string_;
2019 // GC callback function, called before and after mark-compact GC.
2020 // Allocations in the callback function are disallowed.
2021 struct GCPrologueCallbackPair {
2022 GCPrologueCallbackPair(v8::Isolate::GCPrologueCallback callback,
2025 : callback(callback), gc_type(gc_type), pass_isolate_(pass_isolate) {
2027 bool operator==(const GCPrologueCallbackPair& pair) const {
2028 return pair.callback == callback;
2030 v8::Isolate::GCPrologueCallback callback;
2032 // TODO(dcarney): remove variable
2035 List<GCPrologueCallbackPair> gc_prologue_callbacks_;
2037 struct GCEpilogueCallbackPair {
2038 GCEpilogueCallbackPair(v8::Isolate::GCPrologueCallback callback,
2041 : callback(callback), gc_type(gc_type), pass_isolate_(pass_isolate) {
2043 bool operator==(const GCEpilogueCallbackPair& pair) const {
2044 return pair.callback == callback;
2046 v8::Isolate::GCPrologueCallback callback;
2048 // TODO(dcarney): remove variable
2051 List<GCEpilogueCallbackPair> gc_epilogue_callbacks_;
2053 // Support for computing object sizes during GC.
2054 HeapObjectCallback gc_safe_size_of_old_object_;
2055 static int GcSafeSizeOfOldObject(HeapObject* object);
2057 // Update the GC state. Called from the mark-compact collector.
2058 void MarkMapPointersAsEncoded(bool encoded) {
2060 gc_safe_size_of_old_object_ = &GcSafeSizeOfOldObject;
2063 // Code that should be run before and after each GC. Includes some
2064 // reporting/verification activities when compiled with DEBUG set.
2065 void GarbageCollectionPrologue();
2066 void GarbageCollectionEpilogue();
2068 // Pretenuring decisions are made based on feedback collected during new
2069 // space evacuation. Note that between feedback collection and calling this
2070 // method object in old space must not move.
2071 // Right now we only process pretenuring feedback in high promotion mode.
2072 void ProcessPretenuringFeedback();
2074 // Checks whether a global GC is necessary
2075 GarbageCollector SelectGarbageCollector(AllocationSpace space,
2076 const char** reason);
2078 // Performs garbage collection operation.
2079 // Returns whether there is a chance that another major GC could
2080 // collect more garbage.
2081 bool CollectGarbage(
2082 AllocationSpace space,
2083 GarbageCollector collector,
2084 const char* gc_reason,
2085 const char* collector_reason,
2086 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
2088 // Performs garbage collection
2089 // Returns whether there is a chance another major GC could
2090 // collect more garbage.
2091 bool PerformGarbageCollection(
2092 GarbageCollector collector,
2094 const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
2096 inline void UpdateOldSpaceLimits();
2098 // Selects the proper allocation space depending on the given object
2099 // size, pretenuring decision, and preferred old-space.
2100 static AllocationSpace SelectSpace(int object_size,
2101 AllocationSpace preferred_old_space,
2102 PretenureFlag pretenure) {
2103 ASSERT(preferred_old_space == OLD_POINTER_SPACE ||
2104 preferred_old_space == OLD_DATA_SPACE);
2105 if (object_size > Page::kMaxRegularHeapObjectSize) return LO_SPACE;
2106 return (pretenure == TENURED) ? preferred_old_space : NEW_SPACE;
2109 // Allocate an uninitialized fixed array.
2110 MUST_USE_RESULT MaybeObject* AllocateRawFixedArray(
2111 int length, PretenureFlag pretenure);
2113 // Allocate an uninitialized fixed double array.
2114 MUST_USE_RESULT MaybeObject* AllocateRawFixedDoubleArray(
2115 int length, PretenureFlag pretenure);
2117 // Allocate an initialized fixed array with the given filler value.
2118 MUST_USE_RESULT MaybeObject* AllocateFixedArrayWithFiller(
2119 int length, PretenureFlag pretenure, Object* filler);
2121 // Initializes a JSObject based on its map.
2122 void InitializeJSObjectFromMap(JSObject* obj,
2123 FixedArray* properties,
2125 void InitializeAllocationMemento(AllocationMemento* memento,
2126 AllocationSite* allocation_site);
2128 bool CreateInitialMaps();
2129 bool CreateInitialObjects();
2131 // These five Create*EntryStub functions are here and forced to not be inlined
2132 // because of a gcc-4.4 bug that assigns wrong vtable entries.
2133 NO_INLINE(void CreateJSEntryStub());
2134 NO_INLINE(void CreateJSConstructEntryStub());
2136 void CreateFixedStubs();
2137 void CreateStubsRequiringBuiltins();
2139 MUST_USE_RESULT MaybeObject* CreateOddball(const char* to_string,
2143 // Allocate a JSArray with no elements
2144 MUST_USE_RESULT MaybeObject* AllocateJSArray(
2145 ElementsKind elements_kind,
2146 PretenureFlag pretenure = NOT_TENURED);
2148 // Allocate empty fixed array.
2149 MUST_USE_RESULT MaybeObject* AllocateEmptyFixedArray();
2151 // Allocate empty external array of given type.
2152 MUST_USE_RESULT MaybeObject* AllocateEmptyExternalArray(
2153 ExternalArrayType array_type);
2155 // Allocate empty fixed double array.
2156 MUST_USE_RESULT MaybeObject* AllocateEmptyFixedDoubleArray();
2158 // Allocate empty constant pool array.
2159 MUST_USE_RESULT MaybeObject* AllocateEmptyConstantPoolArray();
2161 // Allocate a tenured simple cell.
2162 MUST_USE_RESULT MaybeObject* AllocateCell(Object* value);
2164 // Allocate a tenured JS global property cell initialized with the hole.
2165 MUST_USE_RESULT MaybeObject* AllocatePropertyCell();
2168 MUST_USE_RESULT MaybeObject* AllocateBox(Object* value,
2169 PretenureFlag pretenure);
2171 // Performs a minor collection in new generation.
2174 // Commits from space if it is uncommitted.
2175 void EnsureFromSpaceIsCommitted();
2177 // Uncommit unused semi space.
2178 bool UncommitFromSpace() { return new_space_.UncommitFromSpace(); }
2180 // Fill in bogus values in from space
2181 void ZapFromSpace();
2183 static String* UpdateNewSpaceReferenceInExternalStringTableEntry(
2187 Address DoScavenge(ObjectVisitor* scavenge_visitor, Address new_space_front);
2188 static void ScavengeStoreBufferCallback(Heap* heap,
2190 StoreBufferEvent event);
2192 // Performs a major collection in the whole heap.
2193 void MarkCompact(GCTracer* tracer);
2195 // Code to be run before and after mark-compact.
2196 void MarkCompactPrologue();
2198 void ProcessNativeContexts(WeakObjectRetainer* retainer, bool record_slots);
2199 void ProcessArrayBuffers(WeakObjectRetainer* retainer, bool record_slots);
2200 void ProcessAllocationSites(WeakObjectRetainer* retainer, bool record_slots);
2202 // Deopts all code that contains allocation instruction which are tenured or
2203 // not tenured. Moreover it clears the pretenuring allocation site statistics.
2204 void ResetAllAllocationSitesDependentCode(PretenureFlag flag);
2206 // Evaluates local pretenuring for the old space and calls
2207 // ResetAllTenuredAllocationSitesDependentCode if too many objects died in
2209 void EvaluateOldSpaceLocalPretenuring(uint64_t size_of_objects_before_gc);
2211 // Called on heap tear-down.
2212 void TearDownArrayBuffers();
2214 // Record statistics before and after garbage collection.
2215 void ReportStatisticsBeforeGC();
2216 void ReportStatisticsAfterGC();
2218 // Slow part of scavenge object.
2219 static void ScavengeObjectSlow(HeapObject** p, HeapObject* object);
2221 // Initializes a function with a shared part and prototype.
2222 // Note: this code was factored out of AllocateFunction such that
2223 // other parts of the VM could use it. Specifically, a function that creates
2224 // instances of type JS_FUNCTION_TYPE benefit from the use of this function.
2225 // Please note this does not perform a garbage collection.
2226 inline void InitializeFunction(
2227 JSFunction* function,
2228 SharedFunctionInfo* shared,
2231 // Total RegExp code ever generated
2232 double total_regexp_code_generated_;
2236 // Allocates a small number to string cache.
2237 MUST_USE_RESULT MaybeObject* AllocateInitialNumberStringCache();
2238 // Creates and installs the full-sized number string cache.
2239 void AllocateFullSizeNumberStringCache();
2240 // Get the length of the number to string cache based on the max semispace
2242 int FullSizeNumberStringCacheLength();
2243 // Flush the number to string cache.
2244 void FlushNumberStringCache();
2246 void UpdateSurvivalRateTrend(int start_new_space_size);
2248 enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
2250 static const int kYoungSurvivalRateHighThreshold = 90;
2251 static const int kYoungSurvivalRateLowThreshold = 10;
2252 static const int kYoungSurvivalRateAllowedDeviation = 15;
2254 static const int kOldSurvivalRateLowThreshold = 20;
2256 int young_survivors_after_last_gc_;
2257 int high_survival_rate_period_length_;
2258 int low_survival_rate_period_length_;
2259 double survival_rate_;
2260 SurvivalRateTrend previous_survival_rate_trend_;
2261 SurvivalRateTrend survival_rate_trend_;
2263 void set_survival_rate_trend(SurvivalRateTrend survival_rate_trend) {
2264 ASSERT(survival_rate_trend != FLUCTUATING);
2265 previous_survival_rate_trend_ = survival_rate_trend_;
2266 survival_rate_trend_ = survival_rate_trend;
2269 SurvivalRateTrend survival_rate_trend() {
2270 if (survival_rate_trend_ == STABLE) {
2272 } else if (previous_survival_rate_trend_ == STABLE) {
2273 return survival_rate_trend_;
2274 } else if (survival_rate_trend_ != previous_survival_rate_trend_) {
2277 return survival_rate_trend_;
2281 bool IsStableOrIncreasingSurvivalTrend() {
2282 switch (survival_rate_trend()) {
2291 bool IsStableOrDecreasingSurvivalTrend() {
2292 switch (survival_rate_trend()) {
2301 bool IsIncreasingSurvivalTrend() {
2302 return survival_rate_trend() == INCREASING;
2305 bool IsHighSurvivalRate() {
2306 return high_survival_rate_period_length_ > 0;
2309 bool IsLowSurvivalRate() {
2310 return low_survival_rate_period_length_ > 0;
2313 void SelectScavengingVisitorsTable();
2315 void StartIdleRound() {
2316 mark_sweeps_since_idle_round_started_ = 0;
2319 void FinishIdleRound() {
2320 mark_sweeps_since_idle_round_started_ = kMaxMarkSweepsInIdleRound;
2321 scavenges_since_last_idle_round_ = 0;
2324 bool EnoughGarbageSinceLastIdleRound() {
2325 return (scavenges_since_last_idle_round_ >= kIdleScavengeThreshold);
2328 // Estimates how many milliseconds a Mark-Sweep would take to complete.
2329 // In idle notification handler we assume that this function will return:
2330 // - a number less than 10 for small heaps, which are less than 8Mb.
2331 // - a number greater than 10 for large heaps, which are greater than 32Mb.
2332 int TimeMarkSweepWouldTakeInMs() {
2333 // Rough estimate of how many megabytes of heap can be processed in 1 ms.
2334 static const int kMbPerMs = 2;
2336 int heap_size_mb = static_cast<int>(SizeOfObjects() / MB);
2337 return heap_size_mb / kMbPerMs;
2340 // Returns true if no more GC work is left.
2341 bool IdleGlobalGC();
2343 void AdvanceIdleIncrementalMarking(intptr_t step_size);
2345 void ClearObjectStats(bool clear_last_time_stats = false);
2347 void set_weak_object_to_code_table(Object* value) {
2348 ASSERT(!InNewSpace(value));
2349 weak_object_to_code_table_ = value;
2352 Object** weak_object_to_code_table_address() {
2353 return &weak_object_to_code_table_;
2356 static const int kInitialStringTableSize = 2048;
2357 static const int kInitialEvalCacheSize = 64;
2358 static const int kInitialNumberStringCacheSize = 256;
2360 // Object counts and used memory by InstanceType
2361 size_t object_counts_[OBJECT_STATS_COUNT];
2362 size_t object_counts_last_time_[OBJECT_STATS_COUNT];
2363 size_t object_sizes_[OBJECT_STATS_COUNT];
2364 size_t object_sizes_last_time_[OBJECT_STATS_COUNT];
2366 // Maximum GC pause.
2367 double max_gc_pause_;
2369 // Total time spent in GC.
2370 double total_gc_time_ms_;
2372 // Maximum size of objects alive after GC.
2373 intptr_t max_alive_after_gc_;
2375 // Minimal interval between two subsequent collections.
2376 double min_in_mutator_;
2378 // Size of objects alive after last GC.
2379 intptr_t alive_after_last_gc_;
2381 double last_gc_end_timestamp_;
2383 // Cumulative GC time spent in marking
2384 double marking_time_;
2386 // Cumulative GC time spent in sweeping
2387 double sweeping_time_;
2389 MarkCompactCollector mark_compact_collector_;
2391 StoreBuffer store_buffer_;
2395 IncrementalMarking incremental_marking_;
2397 int number_idle_notifications_;
2398 unsigned int last_idle_notification_gc_count_;
2399 bool last_idle_notification_gc_count_init_;
2401 int mark_sweeps_since_idle_round_started_;
2402 unsigned int gc_count_at_last_idle_gc_;
2403 int scavenges_since_last_idle_round_;
2405 // These two counters are monotomically increasing and never reset.
2406 size_t full_codegen_bytes_generated_;
2407 size_t crankshaft_codegen_bytes_generated_;
2409 // If the --deopt_every_n_garbage_collections flag is set to a positive value,
2410 // this variable holds the number of garbage collections since the last
2411 // deoptimization triggered by garbage collection.
2412 int gcs_since_last_deopt_;
2415 int no_weak_object_verification_scope_depth_;
2419 static const int kAllocationSiteScratchpadSize = 256;
2420 int allocation_sites_scratchpad_length;
2421 AllocationSite* allocation_sites_scratchpad[kAllocationSiteScratchpadSize];
2423 static const int kMaxMarkSweepsInIdleRound = 7;
2424 static const int kIdleScavengeThreshold = 5;
2426 // Shared state read by the scavenge collector and set by ScavengeObject.
2427 PromotionQueue promotion_queue_;
2429 // Flag is set when the heap has been configured. The heap can be repeatedly
2430 // configured through the API until it is set up.
2433 ExternalStringTable external_string_table_;
2435 VisitorDispatchTable<ScavengingCallback> scavenging_visitors_table_;
2437 MemoryChunk* chunks_queued_for_free_;
2439 Mutex* relocation_mutex_;
2441 bool relocation_mutex_locked_by_optimizer_thread_;
2444 friend class Factory;
2445 friend class GCTracer;
2446 friend class DisallowAllocationFailure;
2447 friend class AlwaysAllocateScope;
2449 friend class Isolate;
2450 friend class MarkCompactCollector;
2451 friend class MarkCompactMarkingVisitor;
2452 friend class MapCompact;
2454 friend class NoWeakObjectVerificationScope;
2457 DISALLOW_COPY_AND_ASSIGN(Heap);
2463 static const int kStartMarker = 0xDECADE00;
2464 static const int kEndMarker = 0xDECADE01;
2466 int* start_marker; // 0
2467 int* new_space_size; // 1
2468 int* new_space_capacity; // 2
2469 intptr_t* old_pointer_space_size; // 3
2470 intptr_t* old_pointer_space_capacity; // 4
2471 intptr_t* old_data_space_size; // 5
2472 intptr_t* old_data_space_capacity; // 6
2473 intptr_t* code_space_size; // 7
2474 intptr_t* code_space_capacity; // 8
2475 intptr_t* map_space_size; // 9
2476 intptr_t* map_space_capacity; // 10
2477 intptr_t* cell_space_size; // 11
2478 intptr_t* cell_space_capacity; // 12
2479 intptr_t* lo_space_size; // 13
2480 int* global_handle_count; // 14
2481 int* weak_global_handle_count; // 15
2482 int* pending_global_handle_count; // 16
2483 int* near_death_global_handle_count; // 17
2484 int* free_global_handle_count; // 18
2485 intptr_t* memory_allocator_size; // 19
2486 intptr_t* memory_allocator_capacity; // 20
2487 int* objects_per_type; // 21
2488 int* size_per_type; // 22
2489 int* os_error; // 23
2490 int* end_marker; // 24
2491 intptr_t* property_cell_space_size; // 25
2492 intptr_t* property_cell_space_capacity; // 26
2496 class DisallowAllocationFailure {
2498 inline DisallowAllocationFailure();
2499 inline ~DisallowAllocationFailure();
2508 class AlwaysAllocateScope {
2510 inline AlwaysAllocateScope();
2511 inline ~AlwaysAllocateScope();
2514 // Implicitly disable artificial allocation failures.
2515 DisallowAllocationFailure disallow_allocation_failure_;
2520 class NoWeakObjectVerificationScope {
2522 inline NoWeakObjectVerificationScope();
2523 inline ~NoWeakObjectVerificationScope();
2528 // Visitor class to verify interior pointers in spaces that do not contain
2529 // or care about intergenerational references. All heap object pointers have to
2530 // point into the heap to a location that has a map pointer at its first word.
2531 // Caveat: Heap::Contains is an approximation because it can return true for
2532 // objects in a heap space but above the allocation pointer.
2533 class VerifyPointersVisitor: public ObjectVisitor {
2535 inline void VisitPointers(Object** start, Object** end);
2539 // Space iterator for iterating over all spaces of the heap. Returns each space
2540 // in turn, and null when it is done.
2541 class AllSpaces BASE_EMBEDDED {
2543 explicit AllSpaces(Heap* heap) : heap_(heap), counter_(FIRST_SPACE) {}
2551 // Space iterator for iterating over all old spaces of the heap: Old pointer
2552 // space, old data space and code space. Returns each space in turn, and null
2554 class OldSpaces BASE_EMBEDDED {
2556 explicit OldSpaces(Heap* heap) : heap_(heap), counter_(OLD_POINTER_SPACE) {}
2564 // Space iterator for iterating over all the paged spaces of the heap: Map
2565 // space, old pointer space, old data space, code space and cell space. Returns
2566 // each space in turn, and null when it is done.
2567 class PagedSpaces BASE_EMBEDDED {
2569 explicit PagedSpaces(Heap* heap) : heap_(heap), counter_(OLD_POINTER_SPACE) {}
2577 // Space iterator for iterating over all spaces of the heap.
2578 // For each space an object iterator is provided. The deallocation of the
2579 // returned object iterators is handled by the space iterator.
2580 class SpaceIterator : public Malloced {
2582 explicit SpaceIterator(Heap* heap);
2583 SpaceIterator(Heap* heap, HeapObjectCallback size_func);
2584 virtual ~SpaceIterator();
2587 ObjectIterator* next();
2590 ObjectIterator* CreateIterator();
2593 int current_space_; // from enum AllocationSpace.
2594 ObjectIterator* iterator_; // object iterator for the current space.
2595 HeapObjectCallback size_func_;
2599 // A HeapIterator provides iteration over the whole heap. It
2600 // aggregates the specific iterators for the different spaces as
2601 // these can only iterate over one space only.
2603 // HeapIterator can skip free list nodes (that is, de-allocated heap
2604 // objects that still remain in the heap). As implementation of free
2605 // nodes filtering uses GC marks, it can't be used during MS/MC GC
2606 // phases. Also, it is forbidden to interrupt iteration in this mode,
2607 // as this will leave heap objects marked (and thus, unusable).
2608 class HeapObjectsFilter;
2610 class HeapIterator BASE_EMBEDDED {
2612 enum HeapObjectsFiltering {
2617 explicit HeapIterator(Heap* heap);
2618 HeapIterator(Heap* heap, HeapObjectsFiltering filtering);
2625 // Perform the initialization.
2627 // Perform all necessary shutdown (destruction) work.
2629 HeapObject* NextObject();
2632 HeapObjectsFiltering filtering_;
2633 HeapObjectsFilter* filter_;
2634 // Space iterator for iterating all the spaces.
2635 SpaceIterator* space_iterator_;
2636 // Object iterator for the space currently being iterated.
2637 ObjectIterator* object_iterator_;
2641 // Cache for mapping (map, property name) into field offset.
2642 // Cleared at startup and prior to mark sweep collection.
2643 class KeyedLookupCache {
2645 // Lookup field offset for (map, name). If absent, -1 is returned.
2646 int Lookup(Map* map, Name* name);
2648 // Update an element in the cache.
2649 void Update(Map* map, Name* name, int field_offset);
2654 static const int kLength = 256;
2655 static const int kCapacityMask = kLength - 1;
2656 static const int kMapHashShift = 5;
2657 static const int kHashMask = -4; // Zero the last two bits.
2658 static const int kEntriesPerBucket = 4;
2659 static const int kNotFound = -1;
2661 // kEntriesPerBucket should be a power of 2.
2662 STATIC_ASSERT((kEntriesPerBucket & (kEntriesPerBucket - 1)) == 0);
2663 STATIC_ASSERT(kEntriesPerBucket == -kHashMask);
2666 KeyedLookupCache() {
2667 for (int i = 0; i < kLength; ++i) {
2668 keys_[i].map = NULL;
2669 keys_[i].name = NULL;
2670 field_offsets_[i] = kNotFound;
2674 static inline int Hash(Map* map, Name* name);
2676 // Get the address of the keys and field_offsets arrays. Used in
2677 // generated code to perform cache lookups.
2678 Address keys_address() {
2679 return reinterpret_cast<Address>(&keys_);
2682 Address field_offsets_address() {
2683 return reinterpret_cast<Address>(&field_offsets_);
2692 int field_offsets_[kLength];
2694 friend class ExternalReference;
2695 friend class Isolate;
2696 DISALLOW_COPY_AND_ASSIGN(KeyedLookupCache);
2700 // Cache for mapping (map, property name) into descriptor index.
2701 // The cache contains both positive and negative results.
2702 // Descriptor index equals kNotFound means the property is absent.
2703 // Cleared at startup and prior to any gc.
2704 class DescriptorLookupCache {
2706 // Lookup descriptor index for (map, name).
2707 // If absent, kAbsent is returned.
2708 int Lookup(Map* source, Name* name) {
2709 if (!name->IsUniqueName()) return kAbsent;
2710 int index = Hash(source, name);
2711 Key& key = keys_[index];
2712 if ((key.source == source) && (key.name == name)) return results_[index];
2716 // Update an element in the cache.
2717 void Update(Map* source, Name* name, int result) {
2718 ASSERT(result != kAbsent);
2719 if (name->IsUniqueName()) {
2720 int index = Hash(source, name);
2721 Key& key = keys_[index];
2722 key.source = source;
2724 results_[index] = result;
2731 static const int kAbsent = -2;
2734 DescriptorLookupCache() {
2735 for (int i = 0; i < kLength; ++i) {
2736 keys_[i].source = NULL;
2737 keys_[i].name = NULL;
2738 results_[i] = kAbsent;
2742 static int Hash(Object* source, Name* name) {
2743 // Uses only lower 32 bits if pointers are larger.
2744 uint32_t source_hash =
2745 static_cast<uint32_t>(reinterpret_cast<uintptr_t>(source))
2746 >> kPointerSizeLog2;
2747 uint32_t name_hash =
2748 static_cast<uint32_t>(reinterpret_cast<uintptr_t>(name))
2749 >> kPointerSizeLog2;
2750 return (source_hash ^ name_hash) % kLength;
2753 static const int kLength = 64;
2760 int results_[kLength];
2762 friend class Isolate;
2763 DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache);
2767 // GCTracer collects and prints ONE line after each garbage collector
2768 // invocation IFF --trace_gc is used.
2770 class GCTracer BASE_EMBEDDED {
2772 class Scope BASE_EMBEDDED {
2780 MC_UPDATE_NEW_TO_NEW_POINTERS,
2781 MC_UPDATE_ROOT_TO_NEW_POINTERS,
2782 MC_UPDATE_OLD_TO_NEW_POINTERS,
2783 MC_UPDATE_POINTERS_TO_EVACUATED,
2784 MC_UPDATE_POINTERS_BETWEEN_EVACUATED,
2785 MC_UPDATE_MISC_POINTERS,
2786 MC_WEAKCOLLECTION_PROCESS,
2787 MC_WEAKCOLLECTION_CLEAR,
2792 Scope(GCTracer* tracer, ScopeId scope)
2795 start_time_ = OS::TimeCurrentMillis();
2799 ASSERT(scope_ < kNumberOfScopes); // scope_ is unsigned.
2800 tracer_->scopes_[scope_] += OS::TimeCurrentMillis() - start_time_;
2809 explicit GCTracer(Heap* heap,
2810 const char* gc_reason,
2811 const char* collector_reason);
2814 // Sets the collector.
2815 void set_collector(GarbageCollector collector) { collector_ = collector; }
2817 // Sets the GC count.
2818 void set_gc_count(unsigned int count) { gc_count_ = count; }
2820 // Sets the full GC count.
2821 void set_full_gc_count(int count) { full_gc_count_ = count; }
2823 void increment_promoted_objects_size(int object_size) {
2824 promoted_objects_size_ += object_size;
2827 void increment_nodes_died_in_new_space() {
2828 nodes_died_in_new_space_++;
2831 void increment_nodes_copied_in_new_space() {
2832 nodes_copied_in_new_space_++;
2835 void increment_nodes_promoted() {
2840 // Returns a string matching the collector.
2841 const char* CollectorString();
2843 // Returns size of object in heap (in MB).
2844 inline double SizeOfHeapObjects();
2846 // Timestamp set in the constructor.
2849 // Size of objects in heap set in constructor.
2850 intptr_t start_object_size_;
2852 // Size of memory allocated from OS set in constructor.
2853 intptr_t start_memory_size_;
2855 // Type of collector.
2856 GarbageCollector collector_;
2858 // A count (including this one, e.g. the first collection is 1) of the
2859 // number of garbage collections.
2860 unsigned int gc_count_;
2862 // A count (including this one) of the number of full garbage collections.
2865 // Amounts of time spent in different scopes during GC.
2866 double scopes_[Scope::kNumberOfScopes];
2868 // Total amount of space either wasted or contained in one of free lists
2869 // before the current GC.
2870 intptr_t in_free_list_or_wasted_before_gc_;
2872 // Difference between space used in the heap at the beginning of the current
2873 // collection and the end of the previous collection.
2874 intptr_t allocated_since_last_gc_;
2876 // Amount of time spent in mutator that is time elapsed between end of the
2877 // previous collection and the beginning of the current one.
2878 double spent_in_mutator_;
2880 // Size of objects promoted during the current collection.
2881 intptr_t promoted_objects_size_;
2883 // Number of died nodes in the new space.
2884 int nodes_died_in_new_space_;
2886 // Number of copied nodes to the new space.
2887 int nodes_copied_in_new_space_;
2889 // Number of promoted nodes to the old space.
2890 int nodes_promoted_;
2892 // Incremental marking steps counters.
2895 double longest_step_;
2896 int steps_count_since_last_gc_;
2897 double steps_took_since_last_gc_;
2901 const char* gc_reason_;
2902 const char* collector_reason_;
2906 class RegExpResultsCache {
2908 enum ResultsCacheType { REGEXP_MULTIPLE_INDICES, STRING_SPLIT_SUBSTRINGS };
2910 // Attempt to retrieve a cached result. On failure, 0 is returned as a Smi.
2911 // On success, the returned result is guaranteed to be a COW-array.
2912 static Object* Lookup(Heap* heap,
2914 Object* key_pattern,
2915 ResultsCacheType type);
2916 // Attempt to add value_array to the cache specified by type. On success,
2917 // value_array is turned into a COW-array.
2918 static void Enter(Heap* heap,
2920 Object* key_pattern,
2921 FixedArray* value_array,
2922 ResultsCacheType type);
2923 static void Clear(FixedArray* cache);
2924 static const int kRegExpResultsCacheSize = 0x100;
2927 static const int kArrayEntriesPerCacheEntry = 4;
2928 static const int kStringOffset = 0;
2929 static const int kPatternOffset = 1;
2930 static const int kArrayOffset = 2;
2934 // Abstract base class for checking whether a weak object should be retained.
2935 class WeakObjectRetainer {
2937 virtual ~WeakObjectRetainer() {}
2939 // Return whether this object should be retained. If NULL is returned the
2940 // object has no references. Otherwise the address of the retained object
2941 // should be returned as in some GC situations the object has been moved.
2942 virtual Object* RetainAs(Object* object) = 0;
2946 // Intrusive object marking uses least significant bit of
2947 // heap object's map word to mark objects.
2948 // Normally all map words have least significant bit set
2949 // because they contain tagged map pointer.
2950 // If the bit is not set object is marked.
2951 // All objects should be unmarked before resuming
2952 // JavaScript execution.
2953 class IntrusiveMarking {
2955 static bool IsMarked(HeapObject* object) {
2956 return (object->map_word().ToRawValue() & kNotMarkedBit) == 0;
2959 static void ClearMark(HeapObject* object) {
2960 uintptr_t map_word = object->map_word().ToRawValue();
2961 object->set_map_word(MapWord::FromRawValue(map_word | kNotMarkedBit));
2962 ASSERT(!IsMarked(object));
2965 static void SetMark(HeapObject* object) {
2966 uintptr_t map_word = object->map_word().ToRawValue();
2967 object->set_map_word(MapWord::FromRawValue(map_word & ~kNotMarkedBit));
2968 ASSERT(IsMarked(object));
2971 static Map* MapOfMarkedObject(HeapObject* object) {
2972 uintptr_t map_word = object->map_word().ToRawValue();
2973 return MapWord::FromRawValue(map_word | kNotMarkedBit).ToMap();
2976 static int SizeOfMarkedObject(HeapObject* object) {
2977 return object->SizeFromMap(MapOfMarkedObject(object));
2981 static const uintptr_t kNotMarkedBit = 0x1;
2982 STATIC_ASSERT((kHeapObjectTag & kNotMarkedBit) != 0);
2987 // Helper class for tracing paths to a search target Object from all roots.
2988 // The TracePathFrom() method can be used to trace paths from a specific
2989 // object to the search target object.
2990 class PathTracer : public ObjectVisitor {
2993 FIND_ALL, // Will find all matches.
2994 FIND_FIRST // Will stop the search after first match.
2997 // For the WhatToFind arg, if FIND_FIRST is specified, tracing will stop
2998 // after the first match. If FIND_ALL is specified, then tracing will be
2999 // done for all matches.
3000 PathTracer(Object* search_target,
3001 WhatToFind what_to_find,
3002 VisitMode visit_mode)
3003 : search_target_(search_target),
3004 found_target_(false),
3005 found_target_in_trace_(false),
3006 what_to_find_(what_to_find),
3007 visit_mode_(visit_mode),
3011 virtual void VisitPointers(Object** start, Object** end);
3014 void TracePathFrom(Object** root);
3016 bool found() const { return found_target_; }
3018 static Object* const kAnyGlobalObject;
3022 class UnmarkVisitor;
3024 void MarkRecursively(Object** p, MarkVisitor* mark_visitor);
3025 void UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor);
3026 virtual void ProcessResults();
3028 // Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
3029 static const int kMarkTag = 2;
3031 Object* search_target_;
3033 bool found_target_in_trace_;
3034 WhatToFind what_to_find_;
3035 VisitMode visit_mode_;
3036 List<Object*> object_stack_;
3038 DisallowHeapAllocation no_allocation; // i.e. no gc allowed.
3041 DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
3045 } } // namespace v8::internal
3047 #endif // V8_HEAP_H_