Upgrade to 3.29
Update V8 to 3.29.88.17 and update makefiles to support building on
all the relevant platforms.
Bug: 17370214
Change-Id: Ia3407c157fd8d72a93e23d8318ccaf6ecf77fa4e
diff --git a/src/heap/heap.h b/src/heap/heap.h
new file mode 100644
index 0000000..c9d0f31
--- /dev/null
+++ b/src/heap/heap.h
@@ -0,0 +1,2503 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_HEAP_H_
+#define V8_HEAP_HEAP_H_
+
+#include <cmath>
+
+#include "src/allocation.h"
+#include "src/assert-scope.h"
+#include "src/counters.h"
+#include "src/globals.h"
+#include "src/heap/gc-idle-time-handler.h"
+#include "src/heap/gc-tracer.h"
+#include "src/heap/incremental-marking.h"
+#include "src/heap/mark-compact.h"
+#include "src/heap/objects-visiting.h"
+#include "src/heap/spaces.h"
+#include "src/heap/store-buffer.h"
+#include "src/list.h"
+#include "src/splay-tree-inl.h"
+
+namespace v8 {
+namespace internal {
+
+// Defines all the roots in Heap.
+#define STRONG_ROOT_LIST(V) \
+ V(Map, byte_array_map, ByteArrayMap) \
+ V(Map, free_space_map, FreeSpaceMap) \
+ V(Map, one_pointer_filler_map, OnePointerFillerMap) \
+ V(Map, two_pointer_filler_map, TwoPointerFillerMap) \
+ /* Cluster the most popular ones in a few cache lines here at the top. */ \
+ V(Smi, store_buffer_top, StoreBufferTop) \
+ V(Oddball, undefined_value, UndefinedValue) \
+ V(Oddball, the_hole_value, TheHoleValue) \
+ V(Oddball, null_value, NullValue) \
+ V(Oddball, true_value, TrueValue) \
+ V(Oddball, false_value, FalseValue) \
+ V(Oddball, uninitialized_value, UninitializedValue) \
+ V(Oddball, exception, Exception) \
+ V(Map, cell_map, CellMap) \
+ V(Map, global_property_cell_map, GlobalPropertyCellMap) \
+ V(Map, shared_function_info_map, SharedFunctionInfoMap) \
+ V(Map, meta_map, MetaMap) \
+ V(Map, heap_number_map, HeapNumberMap) \
+ V(Map, mutable_heap_number_map, MutableHeapNumberMap) \
+ V(Map, native_context_map, NativeContextMap) \
+ V(Map, fixed_array_map, FixedArrayMap) \
+ V(Map, code_map, CodeMap) \
+ V(Map, scope_info_map, ScopeInfoMap) \
+ V(Map, fixed_cow_array_map, FixedCOWArrayMap) \
+ V(Map, fixed_double_array_map, FixedDoubleArrayMap) \
+ V(Map, constant_pool_array_map, ConstantPoolArrayMap) \
+ V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \
+ V(Map, hash_table_map, HashTableMap) \
+ V(Map, ordered_hash_table_map, OrderedHashTableMap) \
+ V(FixedArray, empty_fixed_array, EmptyFixedArray) \
+ V(ByteArray, empty_byte_array, EmptyByteArray) \
+ V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
+ V(ConstantPoolArray, empty_constant_pool_array, EmptyConstantPoolArray) \
+ V(Oddball, arguments_marker, ArgumentsMarker) \
+ /* The roots above this line should be boring from a GC point of view. */ \
+ /* This means they are never in new space and never on a page that is */ \
+ /* being compacted. */ \
+ V(FixedArray, number_string_cache, NumberStringCache) \
+ V(Object, instanceof_cache_function, InstanceofCacheFunction) \
+ V(Object, instanceof_cache_map, InstanceofCacheMap) \
+ V(Object, instanceof_cache_answer, InstanceofCacheAnswer) \
+ V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \
+ V(FixedArray, string_split_cache, StringSplitCache) \
+ V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \
+ V(Oddball, termination_exception, TerminationException) \
+ V(Smi, hash_seed, HashSeed) \
+ V(Map, symbol_map, SymbolMap) \
+ V(Map, string_map, StringMap) \
+ V(Map, one_byte_string_map, OneByteStringMap) \
+ V(Map, cons_string_map, ConsStringMap) \
+ V(Map, cons_one_byte_string_map, ConsOneByteStringMap) \
+ V(Map, sliced_string_map, SlicedStringMap) \
+ V(Map, sliced_one_byte_string_map, SlicedOneByteStringMap) \
+ V(Map, external_string_map, ExternalStringMap) \
+ V(Map, external_string_with_one_byte_data_map, \
+ ExternalStringWithOneByteDataMap) \
+ V(Map, external_one_byte_string_map, ExternalOneByteStringMap) \
+ V(Map, short_external_string_map, ShortExternalStringMap) \
+ V(Map, short_external_string_with_one_byte_data_map, \
+ ShortExternalStringWithOneByteDataMap) \
+ V(Map, internalized_string_map, InternalizedStringMap) \
+ V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap) \
+ V(Map, external_internalized_string_map, ExternalInternalizedStringMap) \
+ V(Map, external_internalized_string_with_one_byte_data_map, \
+ ExternalInternalizedStringWithOneByteDataMap) \
+ V(Map, external_one_byte_internalized_string_map, \
+ ExternalOneByteInternalizedStringMap) \
+ V(Map, short_external_internalized_string_map, \
+ ShortExternalInternalizedStringMap) \
+ V(Map, short_external_internalized_string_with_one_byte_data_map, \
+ ShortExternalInternalizedStringWithOneByteDataMap) \
+ V(Map, short_external_one_byte_internalized_string_map, \
+ ShortExternalOneByteInternalizedStringMap) \
+ V(Map, short_external_one_byte_string_map, ShortExternalOneByteStringMap) \
+ V(Map, undetectable_string_map, UndetectableStringMap) \
+ V(Map, undetectable_one_byte_string_map, UndetectableOneByteStringMap) \
+ V(Map, external_int8_array_map, ExternalInt8ArrayMap) \
+ V(Map, external_uint8_array_map, ExternalUint8ArrayMap) \
+ V(Map, external_int16_array_map, ExternalInt16ArrayMap) \
+ V(Map, external_uint16_array_map, ExternalUint16ArrayMap) \
+ V(Map, external_int32_array_map, ExternalInt32ArrayMap) \
+ V(Map, external_uint32_array_map, ExternalUint32ArrayMap) \
+ V(Map, external_float32_array_map, ExternalFloat32ArrayMap) \
+ V(Map, external_float64_array_map, ExternalFloat64ArrayMap) \
+ V(Map, external_uint8_clamped_array_map, ExternalUint8ClampedArrayMap) \
+ V(ExternalArray, empty_external_int8_array, EmptyExternalInt8Array) \
+ V(ExternalArray, empty_external_uint8_array, EmptyExternalUint8Array) \
+ V(ExternalArray, empty_external_int16_array, EmptyExternalInt16Array) \
+ V(ExternalArray, empty_external_uint16_array, EmptyExternalUint16Array) \
+ V(ExternalArray, empty_external_int32_array, EmptyExternalInt32Array) \
+ V(ExternalArray, empty_external_uint32_array, EmptyExternalUint32Array) \
+ V(ExternalArray, empty_external_float32_array, EmptyExternalFloat32Array) \
+ V(ExternalArray, empty_external_float64_array, EmptyExternalFloat64Array) \
+ V(ExternalArray, empty_external_uint8_clamped_array, \
+ EmptyExternalUint8ClampedArray) \
+ V(Map, fixed_uint8_array_map, FixedUint8ArrayMap) \
+ V(Map, fixed_int8_array_map, FixedInt8ArrayMap) \
+ V(Map, fixed_uint16_array_map, FixedUint16ArrayMap) \
+ V(Map, fixed_int16_array_map, FixedInt16ArrayMap) \
+ V(Map, fixed_uint32_array_map, FixedUint32ArrayMap) \
+ V(Map, fixed_int32_array_map, FixedInt32ArrayMap) \
+ V(Map, fixed_float32_array_map, FixedFloat32ArrayMap) \
+ V(Map, fixed_float64_array_map, FixedFloat64ArrayMap) \
+ V(Map, fixed_uint8_clamped_array_map, FixedUint8ClampedArrayMap) \
+ V(FixedTypedArrayBase, empty_fixed_uint8_array, EmptyFixedUint8Array) \
+ V(FixedTypedArrayBase, empty_fixed_int8_array, EmptyFixedInt8Array) \
+ V(FixedTypedArrayBase, empty_fixed_uint16_array, EmptyFixedUint16Array) \
+ V(FixedTypedArrayBase, empty_fixed_int16_array, EmptyFixedInt16Array) \
+ V(FixedTypedArrayBase, empty_fixed_uint32_array, EmptyFixedUint32Array) \
+ V(FixedTypedArrayBase, empty_fixed_int32_array, EmptyFixedInt32Array) \
+ V(FixedTypedArrayBase, empty_fixed_float32_array, EmptyFixedFloat32Array) \
+ V(FixedTypedArrayBase, empty_fixed_float64_array, EmptyFixedFloat64Array) \
+ V(FixedTypedArrayBase, empty_fixed_uint8_clamped_array, \
+ EmptyFixedUint8ClampedArray) \
+ V(Map, sloppy_arguments_elements_map, SloppyArgumentsElementsMap) \
+ V(Map, function_context_map, FunctionContextMap) \
+ V(Map, catch_context_map, CatchContextMap) \
+ V(Map, with_context_map, WithContextMap) \
+ V(Map, block_context_map, BlockContextMap) \
+ V(Map, module_context_map, ModuleContextMap) \
+ V(Map, global_context_map, GlobalContextMap) \
+ V(Map, undefined_map, UndefinedMap) \
+ V(Map, the_hole_map, TheHoleMap) \
+ V(Map, null_map, NullMap) \
+ V(Map, boolean_map, BooleanMap) \
+ V(Map, uninitialized_map, UninitializedMap) \
+ V(Map, arguments_marker_map, ArgumentsMarkerMap) \
+ V(Map, no_interceptor_result_sentinel_map, NoInterceptorResultSentinelMap) \
+ V(Map, exception_map, ExceptionMap) \
+ V(Map, termination_exception_map, TerminationExceptionMap) \
+ V(Map, message_object_map, JSMessageObjectMap) \
+ V(Map, foreign_map, ForeignMap) \
+ V(HeapNumber, nan_value, NanValue) \
+ V(HeapNumber, infinity_value, InfinityValue) \
+ V(HeapNumber, minus_zero_value, MinusZeroValue) \
+ V(Map, neander_map, NeanderMap) \
+ V(JSObject, message_listeners, MessageListeners) \
+ V(UnseededNumberDictionary, code_stubs, CodeStubs) \
+ V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache) \
+ V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache) \
+ V(Code, js_entry_code, JsEntryCode) \
+ V(Code, js_construct_entry_code, JsConstructEntryCode) \
+ V(FixedArray, natives_source_cache, NativesSourceCache) \
+ V(Script, empty_script, EmptyScript) \
+ V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \
+ V(Cell, undefined_cell, UndefineCell) \
+ V(JSObject, observation_state, ObservationState) \
+ V(Map, external_map, ExternalMap) \
+ V(Object, symbol_registry, SymbolRegistry) \
+ V(Symbol, frozen_symbol, FrozenSymbol) \
+ V(Symbol, nonexistent_symbol, NonExistentSymbol) \
+ V(Symbol, elements_transition_symbol, ElementsTransitionSymbol) \
+ V(SeededNumberDictionary, empty_slow_element_dictionary, \
+ EmptySlowElementDictionary) \
+ V(Symbol, observed_symbol, ObservedSymbol) \
+ V(Symbol, uninitialized_symbol, UninitializedSymbol) \
+ V(Symbol, megamorphic_symbol, MegamorphicSymbol) \
+ V(Symbol, premonomorphic_symbol, PremonomorphicSymbol) \
+ V(Symbol, generic_symbol, GenericSymbol) \
+ V(Symbol, stack_trace_symbol, StackTraceSymbol) \
+ V(Symbol, detailed_stack_trace_symbol, DetailedStackTraceSymbol) \
+ V(Symbol, normal_ic_symbol, NormalICSymbol) \
+ V(Symbol, home_object_symbol, HomeObjectSymbol) \
+ V(FixedArray, materialized_objects, MaterializedObjects) \
+ V(FixedArray, allocation_sites_scratchpad, AllocationSitesScratchpad) \
+ V(FixedArray, microtask_queue, MicrotaskQueue)
+
+// Entries in this list are limited to Smis and are not visited during GC.
+#define SMI_ROOT_LIST(V) \
+ V(Smi, stack_limit, StackLimit) \
+ V(Smi, real_stack_limit, RealStackLimit) \
+ V(Smi, last_script_id, LastScriptId) \
+ V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
+ V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset) \
+ V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset) \
+ V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset)
+
+#define ROOT_LIST(V) \
+ STRONG_ROOT_LIST(V) \
+ SMI_ROOT_LIST(V) \
+ V(StringTable, string_table, StringTable)
+
+// Heap roots that are known to be immortal immovable, for which we can safely
+// skip write barriers.
+#define IMMORTAL_IMMOVABLE_ROOT_LIST(V) \
+ V(byte_array_map) \
+ V(free_space_map) \
+ V(one_pointer_filler_map) \
+ V(two_pointer_filler_map) \
+ V(undefined_value) \
+ V(the_hole_value) \
+ V(null_value) \
+ V(true_value) \
+ V(false_value) \
+ V(uninitialized_value) \
+ V(cell_map) \
+ V(global_property_cell_map) \
+ V(shared_function_info_map) \
+ V(meta_map) \
+ V(heap_number_map) \
+ V(mutable_heap_number_map) \
+ V(native_context_map) \
+ V(fixed_array_map) \
+ V(code_map) \
+ V(scope_info_map) \
+ V(fixed_cow_array_map) \
+ V(fixed_double_array_map) \
+ V(constant_pool_array_map) \
+ V(no_interceptor_result_sentinel) \
+ V(hash_table_map) \
+ V(ordered_hash_table_map) \
+ V(empty_fixed_array) \
+ V(empty_byte_array) \
+ V(empty_descriptor_array) \
+ V(empty_constant_pool_array) \
+ V(arguments_marker) \
+ V(symbol_map) \
+ V(sloppy_arguments_elements_map) \
+ V(function_context_map) \
+ V(catch_context_map) \
+ V(with_context_map) \
+ V(block_context_map) \
+ V(module_context_map) \
+ V(global_context_map) \
+ V(undefined_map) \
+ V(the_hole_map) \
+ V(null_map) \
+ V(boolean_map) \
+ V(uninitialized_map) \
+ V(message_object_map) \
+ V(foreign_map) \
+ V(neander_map)
+
+#define INTERNALIZED_STRING_LIST(V) \
+ V(Object_string, "Object") \
+ V(proto_string, "__proto__") \
+ V(arguments_string, "arguments") \
+ V(Arguments_string, "Arguments") \
+ V(caller_string, "caller") \
+ V(boolean_string, "boolean") \
+ V(Boolean_string, "Boolean") \
+ V(callee_string, "callee") \
+ V(constructor_string, "constructor") \
+ V(dot_result_string, ".result") \
+ V(dot_for_string, ".for.") \
+ V(eval_string, "eval") \
+ V(empty_string, "") \
+ V(function_string, "function") \
+ V(Function_string, "Function") \
+ V(length_string, "length") \
+ V(name_string, "name") \
+ V(null_string, "null") \
+ V(number_string, "number") \
+ V(Number_string, "Number") \
+ V(nan_string, "NaN") \
+ V(source_string, "source") \
+ V(source_url_string, "source_url") \
+ V(source_mapping_url_string, "source_mapping_url") \
+ V(global_string, "global") \
+ V(ignore_case_string, "ignoreCase") \
+ V(multiline_string, "multiline") \
+ V(sticky_string, "sticky") \
+ V(harmony_regexps_string, "harmony_regexps") \
+ V(input_string, "input") \
+ V(index_string, "index") \
+ V(last_index_string, "lastIndex") \
+ V(object_string, "object") \
+ V(prototype_string, "prototype") \
+ V(string_string, "string") \
+ V(String_string, "String") \
+ V(symbol_string, "symbol") \
+ V(Symbol_string, "Symbol") \
+ V(Map_string, "Map") \
+ V(Set_string, "Set") \
+ V(WeakMap_string, "WeakMap") \
+ V(WeakSet_string, "WeakSet") \
+ V(for_string, "for") \
+ V(for_api_string, "for_api") \
+ V(for_intern_string, "for_intern") \
+ V(private_api_string, "private_api") \
+ V(private_intern_string, "private_intern") \
+ V(Date_string, "Date") \
+ V(char_at_string, "CharAt") \
+ V(undefined_string, "undefined") \
+ V(value_of_string, "valueOf") \
+ V(stack_string, "stack") \
+ V(toJSON_string, "toJSON") \
+ V(KeyedLoadMonomorphic_string, "KeyedLoadMonomorphic") \
+ V(KeyedStoreMonomorphic_string, "KeyedStoreMonomorphic") \
+ V(stack_overflow_string, "kStackOverflowBoilerplate") \
+ V(illegal_access_string, "illegal access") \
+ V(cell_value_string, "%cell_value") \
+ V(illegal_argument_string, "illegal argument") \
+ V(identity_hash_string, "v8::IdentityHash") \
+ V(closure_string, "(closure)") \
+ V(dot_string, ".") \
+ V(compare_ic_string, "==") \
+ V(strict_compare_ic_string, "===") \
+ V(infinity_string, "Infinity") \
+ V(minus_infinity_string, "-Infinity") \
+ V(query_colon_string, "(?:)") \
+ V(Generator_string, "Generator") \
+ V(throw_string, "throw") \
+ V(done_string, "done") \
+ V(value_string, "value") \
+ V(next_string, "next") \
+ V(byte_length_string, "byteLength") \
+ V(byte_offset_string, "byteOffset") \
+ V(intl_initialized_marker_string, "v8::intl_initialized_marker") \
+ V(intl_impl_object_string, "v8::intl_object")
+
+// Forward declarations.
+class HeapStats;
+class Isolate;
+class WeakObjectRetainer;
+
+
+typedef String* (*ExternalStringTableUpdaterCallback)(Heap* heap,
+ Object** pointer);
+
+class StoreBufferRebuilder {
+ public:
+ explicit StoreBufferRebuilder(StoreBuffer* store_buffer)
+ : store_buffer_(store_buffer) {}
+
+ void Callback(MemoryChunk* page, StoreBufferEvent event);
+
+ private:
+ StoreBuffer* store_buffer_;
+
+ // We record in this variable how full the store buffer was when we started
+ // iterating over the current page, finding pointers to new space. If the
+ // store buffer overflows again we can exempt the page from the store buffer
+ // by rewinding to this point instead of having to search the store buffer.
+ Object*** start_of_current_page_;
+ // The current page we are scanning in the store buffer iterator.
+ MemoryChunk* current_page_;
+};
+
+
+// A queue of objects promoted during scavenge. Each object is accompanied
+// by it's size to avoid dereferencing a map pointer for scanning.
+class PromotionQueue {
+ public:
+ explicit PromotionQueue(Heap* heap)
+ : front_(NULL),
+ rear_(NULL),
+ limit_(NULL),
+ emergency_stack_(0),
+ heap_(heap) {}
+
+ void Initialize();
+
+ void Destroy() {
+ DCHECK(is_empty());
+ delete emergency_stack_;
+ emergency_stack_ = NULL;
+ }
+
+ Page* GetHeadPage() {
+ return Page::FromAllocationTop(reinterpret_cast<Address>(rear_));
+ }
+
+ void SetNewLimit(Address limit) {
+ limit_ = reinterpret_cast<intptr_t*>(limit);
+
+ if (limit_ <= rear_) {
+ return;
+ }
+
+ RelocateQueueHead();
+ }
+
+ bool IsBelowPromotionQueue(Address to_space_top) {
+ // If the given to-space top pointer and the head of the promotion queue
+ // are not on the same page, then the to-space objects are below the
+ // promotion queue.
+ if (GetHeadPage() != Page::FromAddress(to_space_top)) {
+ return true;
+ }
+ // If the to space top pointer is smaller or equal than the promotion
+ // queue head, then the to-space objects are below the promotion queue.
+ return reinterpret_cast<intptr_t*>(to_space_top) <= rear_;
+ }
+
+ bool is_empty() {
+ return (front_ == rear_) &&
+ (emergency_stack_ == NULL || emergency_stack_->length() == 0);
+ }
+
+ inline void insert(HeapObject* target, int size);
+
+ void remove(HeapObject** target, int* size) {
+ DCHECK(!is_empty());
+ if (front_ == rear_) {
+ Entry e = emergency_stack_->RemoveLast();
+ *target = e.obj_;
+ *size = e.size_;
+ return;
+ }
+
+ if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(front_))) {
+ NewSpacePage* front_page =
+ NewSpacePage::FromAddress(reinterpret_cast<Address>(front_));
+ DCHECK(!front_page->prev_page()->is_anchor());
+ front_ = reinterpret_cast<intptr_t*>(front_page->prev_page()->area_end());
+ }
+ *target = reinterpret_cast<HeapObject*>(*(--front_));
+ *size = static_cast<int>(*(--front_));
+ // Assert no underflow.
+ SemiSpace::AssertValidRange(reinterpret_cast<Address>(rear_),
+ reinterpret_cast<Address>(front_));
+ }
+
+ private:
+ // The front of the queue is higher in the memory page chain than the rear.
+ intptr_t* front_;
+ intptr_t* rear_;
+ intptr_t* limit_;
+
+ static const int kEntrySizeInWords = 2;
+
+ struct Entry {
+ Entry(HeapObject* obj, int size) : obj_(obj), size_(size) {}
+
+ HeapObject* obj_;
+ int size_;
+ };
+ List<Entry>* emergency_stack_;
+
+ Heap* heap_;
+
+ void RelocateQueueHead();
+
+ DISALLOW_COPY_AND_ASSIGN(PromotionQueue);
+};
+
+
+typedef void (*ScavengingCallback)(Map* map, HeapObject** slot,
+ HeapObject* object);
+
+
+// External strings table is a place where all external strings are
+// registered. We need to keep track of such strings to properly
+// finalize them.
+class ExternalStringTable {
+ public:
+ // Registers an external string.
+ inline void AddString(String* string);
+
+ inline void Iterate(ObjectVisitor* v);
+
+ // Restores internal invariant and gets rid of collected strings.
+ // Must be called after each Iterate() that modified the strings.
+ void CleanUp();
+
+ // Destroys all allocated memory.
+ void TearDown();
+
+ private:
+ explicit ExternalStringTable(Heap* heap) : heap_(heap) {}
+
+ friend class Heap;
+
+ inline void Verify();
+
+ inline void AddOldString(String* string);
+
+ // Notifies the table that only a prefix of the new list is valid.
+ inline void ShrinkNewStrings(int position);
+
+ // To speed up scavenge collections new space string are kept
+ // separate from old space strings.
+ List<Object*> new_space_strings_;
+ List<Object*> old_space_strings_;
+
+ Heap* heap_;
+
+ DISALLOW_COPY_AND_ASSIGN(ExternalStringTable);
+};
+
+
+enum ArrayStorageAllocationMode {
+ DONT_INITIALIZE_ARRAY_ELEMENTS,
+ INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE
+};
+
+
+class Heap {
+ public:
+ // Configure heap size in MB before setup. Return false if the heap has been
+ // set up already.
+ bool ConfigureHeap(int max_semi_space_size, int max_old_space_size,
+ int max_executable_size, size_t code_range_size);
+ bool ConfigureHeapDefault();
+
+ // Prepares the heap, setting up memory areas that are needed in the isolate
+ // without actually creating any objects.
+ bool SetUp();
+
+ // Bootstraps the object heap with the core set of objects required to run.
+ // Returns whether it succeeded.
+ bool CreateHeapObjects();
+
+ // Destroys all memory allocated by the heap.
+ void TearDown();
+
+ // Set the stack limit in the roots_ array. Some architectures generate
+ // code that looks here, because it is faster than loading from the static
+ // jslimit_/real_jslimit_ variable in the StackGuard.
+ void SetStackLimits();
+
+ // Returns whether SetUp has been called.
+ bool HasBeenSetUp();
+
+ // Returns the maximum amount of memory reserved for the heap. For
+ // the young generation, we reserve 4 times the amount needed for a
+ // semi space. The young generation consists of two semi spaces and
+ // we reserve twice the amount needed for those in order to ensure
+ // that new space can be aligned to its size.
+ intptr_t MaxReserved() {
+ return 4 * reserved_semispace_size_ + max_old_generation_size_;
+ }
+ int MaxSemiSpaceSize() { return max_semi_space_size_; }
+ int ReservedSemiSpaceSize() { return reserved_semispace_size_; }
+ int InitialSemiSpaceSize() { return initial_semispace_size_; }
+ intptr_t MaxOldGenerationSize() { return max_old_generation_size_; }
+ intptr_t MaxExecutableSize() { return max_executable_size_; }
+
+ // Returns the capacity of the heap in bytes w/o growing. Heap grows when
+ // more spaces are needed until it reaches the limit.
+ intptr_t Capacity();
+
+ // Returns the amount of memory currently committed for the heap.
+ intptr_t CommittedMemory();
+
+ // Returns the amount of executable memory currently committed for the heap.
+ intptr_t CommittedMemoryExecutable();
+
+ // Returns the amount of phyical memory currently committed for the heap.
+ size_t CommittedPhysicalMemory();
+
+ // Returns the maximum amount of memory ever committed for the heap.
+ intptr_t MaximumCommittedMemory() { return maximum_committed_; }
+
+ // Updates the maximum committed memory for the heap. Should be called
+ // whenever a space grows.
+ void UpdateMaximumCommitted();
+
+ // Returns the available bytes in space w/o growing.
+ // Heap doesn't guarantee that it can allocate an object that requires
+ // all available bytes. Check MaxHeapObjectSize() instead.
+ intptr_t Available();
+
+ // Returns of size of all objects residing in the heap.
+ intptr_t SizeOfObjects();
+
+ // Return the starting address and a mask for the new space. And-masking an
+ // address with the mask will result in the start address of the new space
+ // for all addresses in either semispace.
+ Address NewSpaceStart() { return new_space_.start(); }
+ uintptr_t NewSpaceMask() { return new_space_.mask(); }
+ Address NewSpaceTop() { return new_space_.top(); }
+
+ NewSpace* new_space() { return &new_space_; }
+ OldSpace* old_pointer_space() { return old_pointer_space_; }
+ OldSpace* old_data_space() { return old_data_space_; }
+ OldSpace* code_space() { return code_space_; }
+ MapSpace* map_space() { return map_space_; }
+ CellSpace* cell_space() { return cell_space_; }
+ PropertyCellSpace* property_cell_space() { return property_cell_space_; }
+ LargeObjectSpace* lo_space() { return lo_space_; }
+ PagedSpace* paged_space(int idx) {
+ switch (idx) {
+ case OLD_POINTER_SPACE:
+ return old_pointer_space();
+ case OLD_DATA_SPACE:
+ return old_data_space();
+ case MAP_SPACE:
+ return map_space();
+ case CELL_SPACE:
+ return cell_space();
+ case PROPERTY_CELL_SPACE:
+ return property_cell_space();
+ case CODE_SPACE:
+ return code_space();
+ case NEW_SPACE:
+ case LO_SPACE:
+ UNREACHABLE();
+ }
+ return NULL;
+ }
+
+ bool always_allocate() { return always_allocate_scope_depth_ != 0; }
+ Address always_allocate_scope_depth_address() {
+ return reinterpret_cast<Address>(&always_allocate_scope_depth_);
+ }
+
+ Address* NewSpaceAllocationTopAddress() {
+ return new_space_.allocation_top_address();
+ }
+ Address* NewSpaceAllocationLimitAddress() {
+ return new_space_.allocation_limit_address();
+ }
+
+ Address* OldPointerSpaceAllocationTopAddress() {
+ return old_pointer_space_->allocation_top_address();
+ }
+ Address* OldPointerSpaceAllocationLimitAddress() {
+ return old_pointer_space_->allocation_limit_address();
+ }
+
+ Address* OldDataSpaceAllocationTopAddress() {
+ return old_data_space_->allocation_top_address();
+ }
+ Address* OldDataSpaceAllocationLimitAddress() {
+ return old_data_space_->allocation_limit_address();
+ }
+
+ // Returns a deep copy of the JavaScript object.
+ // Properties and elements are copied too.
+ // Optionally takes an AllocationSite to be appended in an AllocationMemento.
+ MUST_USE_RESULT AllocationResult
+ CopyJSObject(JSObject* source, AllocationSite* site = NULL);
+
+ // Clear the Instanceof cache (used when a prototype changes).
+ inline void ClearInstanceofCache();
+
+ // Iterates the whole code space to clear all ICs of the given kind.
+ void ClearAllICsByKind(Code::Kind kind);
+
+ // For use during bootup.
+ void RepairFreeListsAfterBoot();
+
+ template <typename T>
+ static inline bool IsOneByte(T t, int chars);
+
+ // Move len elements within a given array from src_index index to dst_index
+ // index.
+ void MoveElements(FixedArray* array, int dst_index, int src_index, int len);
+
+ // Sloppy mode arguments object size.
+ static const int kSloppyArgumentsObjectSize =
+ JSObject::kHeaderSize + 2 * kPointerSize;
+ // Strict mode arguments has no callee so it is smaller.
+ static const int kStrictArgumentsObjectSize =
+ JSObject::kHeaderSize + 1 * kPointerSize;
+ // Indicies for direct access into argument objects.
+ static const int kArgumentsLengthIndex = 0;
+ // callee is only valid in sloppy mode.
+ static const int kArgumentsCalleeIndex = 1;
+
+ // Finalizes an external string by deleting the associated external
+ // data and clearing the resource pointer.
+ inline void FinalizeExternalString(String* string);
+
+ // Initialize a filler object to keep the ability to iterate over the heap
+ // when introducing gaps within pages.
+ void CreateFillerObjectAt(Address addr, int size);
+
+ bool CanMoveObjectStart(HeapObject* object);
+
+ // Indicates whether live bytes adjustment is triggered from within the GC
+ // code or from mutator code.
+ enum InvocationMode { FROM_GC, FROM_MUTATOR };
+
+ // Maintain consistency of live bytes during incremental marking.
+ void AdjustLiveBytes(Address address, int by, InvocationMode mode);
+
+ // Trim the given array from the left. Note that this relocates the object
+ // start and hence is only valid if there is only a single reference to it.
+ FixedArrayBase* LeftTrimFixedArray(FixedArrayBase* obj, int elements_to_trim);
+
+ // Trim the given array from the right.
+ template<Heap::InvocationMode mode>
+ void RightTrimFixedArray(FixedArrayBase* obj, int elements_to_trim);
+
+ // Converts the given boolean condition to JavaScript boolean value.
+ inline Object* ToBoolean(bool condition);
+
+ // Performs garbage collection operation.
+ // Returns whether there is a chance that another major GC could
+ // collect more garbage.
+ inline bool CollectGarbage(
+ AllocationSpace space, const char* gc_reason = NULL,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ static const int kNoGCFlags = 0;
+ static const int kReduceMemoryFootprintMask = 1;
+ static const int kAbortIncrementalMarkingMask = 2;
+
+ // Making the heap iterable requires us to abort incremental marking.
+ static const int kMakeHeapIterableMask = kAbortIncrementalMarkingMask;
+
+ // Performs a full garbage collection. If (flags & kMakeHeapIterableMask) is
+ // non-zero, then the slower precise sweeper is used, which leaves the heap
+ // in a state where we can iterate over the heap visiting all objects.
+ void CollectAllGarbage(
+ int flags, const char* gc_reason = NULL,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ // Last hope GC, should try to squeeze as much as possible.
+ void CollectAllAvailableGarbage(const char* gc_reason = NULL);
+
+ // Check whether the heap is currently iterable.
+ bool IsHeapIterable();
+
+ // Notify the heap that a context has been disposed.
+ int NotifyContextDisposed();
+
+ inline void increment_scan_on_scavenge_pages() {
+ scan_on_scavenge_pages_++;
+ if (FLAG_gc_verbose) {
+ PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
+ }
+ }
+
+ inline void decrement_scan_on_scavenge_pages() {
+ scan_on_scavenge_pages_--;
+ if (FLAG_gc_verbose) {
+ PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
+ }
+ }
+
+ PromotionQueue* promotion_queue() { return &promotion_queue_; }
+
+ void AddGCPrologueCallback(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type_filter, bool pass_isolate = true);
+ void RemoveGCPrologueCallback(v8::Isolate::GCPrologueCallback callback);
+
+ void AddGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback,
+ GCType gc_type_filter, bool pass_isolate = true);
+ void RemoveGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback);
+
+// Heap root getters. We have versions with and without type::cast() here.
+// You can't use type::cast during GC because the assert fails.
+// TODO(1490): Try removing the unchecked accessors, now that GC marking does
+// not corrupt the map.
+#define ROOT_ACCESSOR(type, name, camel_name) \
+ type* name() { return type::cast(roots_[k##camel_name##RootIndex]); } \
+ type* raw_unchecked_##name() { \
+ return reinterpret_cast<type*>(roots_[k##camel_name##RootIndex]); \
+ }
+ ROOT_LIST(ROOT_ACCESSOR)
+#undef ROOT_ACCESSOR
+
+// Utility type maps
+#define STRUCT_MAP_ACCESSOR(NAME, Name, name) \
+ Map* name##_map() { return Map::cast(roots_[k##Name##MapRootIndex]); }
+ STRUCT_LIST(STRUCT_MAP_ACCESSOR)
+#undef STRUCT_MAP_ACCESSOR
+
+#define STRING_ACCESSOR(name, str) \
+ String* name() { return String::cast(roots_[k##name##RootIndex]); }
+ INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
+#undef STRING_ACCESSOR
+
+ // The hidden_string is special because it is the empty string, but does
+ // not match the empty string.
+ String* hidden_string() { return hidden_string_; }
+
+ void set_native_contexts_list(Object* object) {
+ native_contexts_list_ = object;
+ }
+ Object* native_contexts_list() const { return native_contexts_list_; }
+
+ void set_array_buffers_list(Object* object) { array_buffers_list_ = object; }
+ Object* array_buffers_list() const { return array_buffers_list_; }
+
+ void set_allocation_sites_list(Object* object) {
+ allocation_sites_list_ = object;
+ }
+ Object* allocation_sites_list() { return allocation_sites_list_; }
+
+ // Used in CreateAllocationSiteStub and the (de)serializer.
+ Object** allocation_sites_list_address() { return &allocation_sites_list_; }
+
+ Object* weak_object_to_code_table() { return weak_object_to_code_table_; }
+
+ void set_encountered_weak_collections(Object* weak_collection) {
+ encountered_weak_collections_ = weak_collection;
+ }
+ Object* encountered_weak_collections() const {
+ return encountered_weak_collections_;
+ }
+
+ // Number of mark-sweeps.
+ unsigned int ms_count() { return ms_count_; }
+
+ // Iterates over all roots in the heap.
+ void IterateRoots(ObjectVisitor* v, VisitMode mode);
+ // Iterates over all strong roots in the heap.
+ void IterateStrongRoots(ObjectVisitor* v, VisitMode mode);
+ // Iterates over entries in the smi roots list. Only interesting to the
+ // serializer/deserializer, since GC does not care about smis.
+ void IterateSmiRoots(ObjectVisitor* v);
+ // Iterates over all the other roots in the heap.
+ void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
+
+ // Iterate pointers to from semispace of new space found in memory interval
+ // from start to end.
+ void IterateAndMarkPointersToFromSpace(Address start, Address end,
+ ObjectSlotCallback callback);
+
+ // Returns whether the object resides in new space.
+ inline bool InNewSpace(Object* object);
+ inline bool InNewSpace(Address address);
+ inline bool InNewSpacePage(Address address);
+ inline bool InFromSpace(Object* object);
+ inline bool InToSpace(Object* object);
+
+ // Returns whether the object resides in old pointer space.
+ inline bool InOldPointerSpace(Address address);
+ inline bool InOldPointerSpace(Object* object);
+
+ // Returns whether the object resides in old data space.
+ inline bool InOldDataSpace(Address address);
+ inline bool InOldDataSpace(Object* object);
+
+ // Checks whether an address/object in the heap (including auxiliary
+ // area and unused area).
+ bool Contains(Address addr);
+ bool Contains(HeapObject* value);
+
+ // Checks whether an address/object in a space.
+ // Currently used by tests, serialization and heap verification only.
+ bool InSpace(Address addr, AllocationSpace space);
+ bool InSpace(HeapObject* value, AllocationSpace space);
+
+ // Finds out which space an object should get promoted to based on its type.
+ inline OldSpace* TargetSpace(HeapObject* object);
+ static inline AllocationSpace TargetSpaceId(InstanceType type);
+
+ // Checks whether the given object is allowed to be migrated from it's
+ // current space into the given destination space. Used for debugging.
+ inline bool AllowedToBeMigrated(HeapObject* object, AllocationSpace dest);
+
+ // Sets the stub_cache_ (only used when expanding the dictionary).
+ void public_set_code_stubs(UnseededNumberDictionary* value) {
+ roots_[kCodeStubsRootIndex] = value;
+ }
+
+ // Support for computing object sizes for old objects during GCs. Returns
+ // a function that is guaranteed to be safe for computing object sizes in
+ // the current GC phase.
+ HeapObjectCallback GcSafeSizeOfOldObjectFunction() {
+ return gc_safe_size_of_old_object_;
+ }
+
+ // Sets the non_monomorphic_cache_ (only used when expanding the dictionary).
+ void public_set_non_monomorphic_cache(UnseededNumberDictionary* value) {
+ roots_[kNonMonomorphicCacheRootIndex] = value;
+ }
+
+ void public_set_empty_script(Script* script) {
+ roots_[kEmptyScriptRootIndex] = script;
+ }
+
+ void public_set_store_buffer_top(Address* top) {
+ roots_[kStoreBufferTopRootIndex] = reinterpret_cast<Smi*>(top);
+ }
+
+ void public_set_materialized_objects(FixedArray* objects) {
+ roots_[kMaterializedObjectsRootIndex] = objects;
+ }
+
+ // Generated code can embed this address to get access to the roots.
+ Object** roots_array_start() { return roots_; }
+
+ Address* store_buffer_top_address() {
+ return reinterpret_cast<Address*>(&roots_[kStoreBufferTopRootIndex]);
+ }
+
+#ifdef VERIFY_HEAP
+ // Verify the heap is in its normal state before or after a GC.
+ void Verify();
+
+
+ bool weak_embedded_objects_verification_enabled() {
+ return no_weak_object_verification_scope_depth_ == 0;
+ }
+#endif
+
+#ifdef DEBUG
+ void Print();
+ void PrintHandles();
+
+ void OldPointerSpaceCheckStoreBuffer();
+ void MapSpaceCheckStoreBuffer();
+ void LargeObjectSpaceCheckStoreBuffer();
+
+ // Report heap statistics.
+ void ReportHeapStatistics(const char* title);
+ void ReportCodeStatistics(const char* title);
+#endif
+
+ // Zapping is needed for verify heap, and always done in debug builds.
+ static inline bool ShouldZapGarbage() {
+#ifdef DEBUG
+ return true;
+#else
+#ifdef VERIFY_HEAP
+ return FLAG_verify_heap;
+#else
+ return false;
+#endif
+#endif
+ }
+
+ // Number of "runtime allocations" done so far.
+ uint32_t allocations_count() { return allocations_count_; }
+
+ // Returns deterministic "time" value in ms. Works only with
+ // FLAG_verify_predictable.
+ double synthetic_time() { return allocations_count_ / 2.0; }
+
+ // Print short heap statistics.
+ void PrintShortHeapStatistics();
+
+ // Write barrier support for address[offset] = o.
+ INLINE(void RecordWrite(Address address, int offset));
+
+ // Write barrier support for address[start : start + len[ = o.
+ INLINE(void RecordWrites(Address address, int start, int len));
+
+ enum HeapState { NOT_IN_GC, SCAVENGE, MARK_COMPACT };
+ inline HeapState gc_state() { return gc_state_; }
+
+ inline bool IsInGCPostProcessing() { return gc_post_processing_depth_ > 0; }
+
+#ifdef DEBUG
+ void set_allocation_timeout(int timeout) { allocation_timeout_ = timeout; }
+
+ void TracePathToObjectFrom(Object* target, Object* root);
+ void TracePathToObject(Object* target);
+ void TracePathToGlobal();
+#endif
+
+ // Callback function passed to Heap::Iterate etc. Copies an object if
+ // necessary, the object might be promoted to an old space. The caller must
+ // ensure the precondition that the object is (a) a heap object and (b) in
+ // the heap's from space.
+ static inline void ScavengePointer(HeapObject** p);
+ static inline void ScavengeObject(HeapObject** p, HeapObject* object);
+
+ enum ScratchpadSlotMode { IGNORE_SCRATCHPAD_SLOT, RECORD_SCRATCHPAD_SLOT };
+
+ // If an object has an AllocationMemento trailing it, return it, otherwise
+ // return NULL;
+ inline AllocationMemento* FindAllocationMemento(HeapObject* object);
+
+ // An object may have an AllocationSite associated with it through a trailing
+ // AllocationMemento. Its feedback should be updated when objects are found
+ // in the heap.
+ static inline void UpdateAllocationSiteFeedback(HeapObject* object,
+ ScratchpadSlotMode mode);
+
+ // Support for partial snapshots. After calling this we have a linear
+ // space to write objects in each space.
+ void ReserveSpace(int* sizes, Address* addresses);
+
+ //
+ // Support for the API.
+ //
+
+ void CreateApiObjects();
+
+ inline intptr_t PromotedTotalSize() {
+ int64_t total = PromotedSpaceSizeOfObjects() + PromotedExternalMemorySize();
+ if (total > kMaxInt) return static_cast<intptr_t>(kMaxInt);
+ if (total < 0) return 0;
+ return static_cast<intptr_t>(total);
+ }
+
+ inline intptr_t OldGenerationSpaceAvailable() {
+ return old_generation_allocation_limit_ - PromotedTotalSize();
+ }
+
+ inline intptr_t OldGenerationCapacityAvailable() {
+ return max_old_generation_size_ - PromotedTotalSize();
+ }
+
+ static const intptr_t kMinimumOldGenerationAllocationLimit =
+ 8 * (Page::kPageSize > MB ? Page::kPageSize : MB);
+
+ static const int kPointerMultiplier = i::kPointerSize / 4;
+
+ // The new space size has to be a power of 2. Sizes are in MB.
+ static const int kMaxSemiSpaceSizeLowMemoryDevice = 1 * kPointerMultiplier;
+ static const int kMaxSemiSpaceSizeMediumMemoryDevice = 4 * kPointerMultiplier;
+ static const int kMaxSemiSpaceSizeHighMemoryDevice = 8 * kPointerMultiplier;
+ static const int kMaxSemiSpaceSizeHugeMemoryDevice = 8 * kPointerMultiplier;
+
+ // The old space size has to be a multiple of Page::kPageSize.
+ // Sizes are in MB.
+ static const int kMaxOldSpaceSizeLowMemoryDevice = 128 * kPointerMultiplier;
+ static const int kMaxOldSpaceSizeMediumMemoryDevice =
+ 256 * kPointerMultiplier;
+ static const int kMaxOldSpaceSizeHighMemoryDevice = 512 * kPointerMultiplier;
+ static const int kMaxOldSpaceSizeHugeMemoryDevice = 700 * kPointerMultiplier;
+
+ // The executable size has to be a multiple of Page::kPageSize.
+ // Sizes are in MB.
+ static const int kMaxExecutableSizeLowMemoryDevice = 96 * kPointerMultiplier;
+ static const int kMaxExecutableSizeMediumMemoryDevice =
+ 192 * kPointerMultiplier;
+ static const int kMaxExecutableSizeHighMemoryDevice =
+ 256 * kPointerMultiplier;
+ static const int kMaxExecutableSizeHugeMemoryDevice =
+ 256 * kPointerMultiplier;
+
+ intptr_t OldGenerationAllocationLimit(intptr_t old_gen_size,
+ int freed_global_handles);
+
+ // Indicates whether inline bump-pointer allocation has been disabled.
+ bool inline_allocation_disabled() { return inline_allocation_disabled_; }
+
+ // Switch whether inline bump-pointer allocation should be used.
+ void EnableInlineAllocation();
+ void DisableInlineAllocation();
+
+ // Implements the corresponding V8 API function.
+ bool IdleNotification(int idle_time_in_ms);
+
+ // Declare all the root indices. This defines the root list order.
+ enum RootListIndex {
+#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
+ STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
+#undef ROOT_INDEX_DECLARATION
+
+#define STRING_INDEX_DECLARATION(name, str) k##name##RootIndex,
+ INTERNALIZED_STRING_LIST(STRING_INDEX_DECLARATION)
+#undef STRING_DECLARATION
+
+// Utility type maps
+#define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
+ STRUCT_LIST(DECLARE_STRUCT_MAP)
+#undef DECLARE_STRUCT_MAP
+ kStringTableRootIndex,
+
+#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
+ SMI_ROOT_LIST(ROOT_INDEX_DECLARATION)
+#undef ROOT_INDEX_DECLARATION
+ kRootListLength,
+ kStrongRootListLength = kStringTableRootIndex,
+ kSmiRootsStart = kStringTableRootIndex + 1
+ };
+
+ STATIC_ASSERT(kUndefinedValueRootIndex ==
+ Internals::kUndefinedValueRootIndex);
+ STATIC_ASSERT(kNullValueRootIndex == Internals::kNullValueRootIndex);
+ STATIC_ASSERT(kTrueValueRootIndex == Internals::kTrueValueRootIndex);
+ STATIC_ASSERT(kFalseValueRootIndex == Internals::kFalseValueRootIndex);
+ STATIC_ASSERT(kempty_stringRootIndex == Internals::kEmptyStringRootIndex);
+
+ // Generated code can embed direct references to non-writable roots if
+ // they are in new space.
+ static bool RootCanBeWrittenAfterInitialization(RootListIndex root_index);
+ // Generated code can treat direct references to this root as constant.
+ bool RootCanBeTreatedAsConstant(RootListIndex root_index);
+
+ Map* MapForFixedTypedArray(ExternalArrayType array_type);
+ RootListIndex RootIndexForFixedTypedArray(ExternalArrayType array_type);
+
+ Map* MapForExternalArrayType(ExternalArrayType array_type);
+ RootListIndex RootIndexForExternalArrayType(ExternalArrayType array_type);
+
+ RootListIndex RootIndexForEmptyExternalArray(ElementsKind kind);
+ RootListIndex RootIndexForEmptyFixedTypedArray(ElementsKind kind);
+ ExternalArray* EmptyExternalArrayForMap(Map* map);
+ FixedTypedArrayBase* EmptyFixedTypedArrayForMap(Map* map);
+
+ void RecordStats(HeapStats* stats, bool take_snapshot = false);
+
+ // Copy block of memory from src to dst. Size of block should be aligned
+ // by pointer size.
+ static inline void CopyBlock(Address dst, Address src, int byte_size);
+
+ // Optimized version of memmove for blocks with pointer size aligned sizes and
+ // pointer size aligned addresses.
+ static inline void MoveBlock(Address dst, Address src, int byte_size);
+
+ // Check new space expansion criteria and expand semispaces if it was hit.
+ void CheckNewSpaceExpansionCriteria();
+
+ inline void IncrementPromotedObjectsSize(int object_size) {
+ DCHECK(object_size > 0);
+ promoted_objects_size_ += object_size;
+ }
+
+ inline void IncrementSemiSpaceCopiedObjectSize(int object_size) {
+ DCHECK(object_size > 0);
+ semi_space_copied_object_size_ += object_size;
+ }
+
+ inline void IncrementNodesDiedInNewSpace() { nodes_died_in_new_space_++; }
+
+ inline void IncrementNodesCopiedInNewSpace() { nodes_copied_in_new_space_++; }
+
+ inline void IncrementNodesPromoted() { nodes_promoted_++; }
+
+ inline void IncrementYoungSurvivorsCounter(int survived) {
+ DCHECK(survived >= 0);
+ survived_since_last_expansion_ += survived;
+ }
+
+ inline bool NextGCIsLikelyToBeFull() {
+ if (FLAG_gc_global) return true;
+
+ if (FLAG_stress_compaction && (gc_count_ & 1) != 0) return true;
+
+ intptr_t adjusted_allocation_limit =
+ old_generation_allocation_limit_ - new_space_.Capacity();
+
+ if (PromotedTotalSize() >= adjusted_allocation_limit) return true;
+
+ return false;
+ }
+
+ void UpdateNewSpaceReferencesInExternalStringTable(
+ ExternalStringTableUpdaterCallback updater_func);
+
+ void UpdateReferencesInExternalStringTable(
+ ExternalStringTableUpdaterCallback updater_func);
+
+ void ProcessWeakReferences(WeakObjectRetainer* retainer);
+
+ void VisitExternalResources(v8::ExternalResourceVisitor* visitor);
+
+ // An object should be promoted if the object has survived a
+ // scavenge operation.
+ inline bool ShouldBePromoted(Address old_address, int object_size);
+
+ void ClearJSFunctionResultCaches();
+
+ void ClearNormalizedMapCaches();
+
+ GCTracer* tracer() { return &tracer_; }
+
+ // Returns the size of objects residing in non new spaces.
+ intptr_t PromotedSpaceSizeOfObjects();
+
+ double total_regexp_code_generated() { return total_regexp_code_generated_; }
+ void IncreaseTotalRegexpCodeGenerated(int size) {
+ total_regexp_code_generated_ += size;
+ }
+
+ void IncrementCodeGeneratedBytes(bool is_crankshafted, int size) {
+ if (is_crankshafted) {
+ crankshaft_codegen_bytes_generated_ += size;
+ } else {
+ full_codegen_bytes_generated_ += size;
+ }
+ }
+
+ // Update GC statistics that are tracked on the Heap.
+ void UpdateCumulativeGCStatistics(double duration, double spent_in_mutator,
+ double marking_time);
+
+ // Returns maximum GC pause.
+ double get_max_gc_pause() { return max_gc_pause_; }
+
+ // Returns maximum size of objects alive after GC.
+ intptr_t get_max_alive_after_gc() { return max_alive_after_gc_; }
+
+ // Returns minimal interval between two subsequent collections.
+ double get_min_in_mutator() { return min_in_mutator_; }
+
+ MarkCompactCollector* mark_compact_collector() {
+ return &mark_compact_collector_;
+ }
+
+ StoreBuffer* store_buffer() { return &store_buffer_; }
+
+ Marking* marking() { return &marking_; }
+
+ IncrementalMarking* incremental_marking() { return &incremental_marking_; }
+
+ ExternalStringTable* external_string_table() {
+ return &external_string_table_;
+ }
+
+ // Returns the current sweep generation.
+ int sweep_generation() { return sweep_generation_; }
+
+ inline Isolate* isolate();
+
+ void CallGCPrologueCallbacks(GCType gc_type, GCCallbackFlags flags);
+ void CallGCEpilogueCallbacks(GCType gc_type, GCCallbackFlags flags);
+
+ inline bool OldGenerationAllocationLimitReached();
+
+ inline void DoScavengeObject(Map* map, HeapObject** slot, HeapObject* obj) {
+ scavenging_visitors_table_.GetVisitor(map)(map, slot, obj);
+ }
+
+ void QueueMemoryChunkForFree(MemoryChunk* chunk);
+ void FreeQueuedChunks();
+
+ int gc_count() const { return gc_count_; }
+
+ // Completely clear the Instanceof cache (to stop it keeping objects alive
+ // around a GC).
+ inline void CompletelyClearInstanceofCache();
+
+ // The roots that have an index less than this are always in old space.
+ static const int kOldSpaceRoots = 0x20;
+
+ uint32_t HashSeed() {
+ uint32_t seed = static_cast<uint32_t>(hash_seed()->value());
+ DCHECK(FLAG_randomize_hashes || seed == 0);
+ return seed;
+ }
+
+ void SetArgumentsAdaptorDeoptPCOffset(int pc_offset) {
+ DCHECK(arguments_adaptor_deopt_pc_offset() == Smi::FromInt(0));
+ set_arguments_adaptor_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ void SetConstructStubDeoptPCOffset(int pc_offset) {
+ DCHECK(construct_stub_deopt_pc_offset() == Smi::FromInt(0));
+ set_construct_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ void SetGetterStubDeoptPCOffset(int pc_offset) {
+ DCHECK(getter_stub_deopt_pc_offset() == Smi::FromInt(0));
+ set_getter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ void SetSetterStubDeoptPCOffset(int pc_offset) {
+ DCHECK(setter_stub_deopt_pc_offset() == Smi::FromInt(0));
+ set_setter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ // For post mortem debugging.
+ void RememberUnmappedPage(Address page, bool compacted);
+
+ // Global inline caching age: it is incremented on some GCs after context
+ // disposal. We use it to flush inline caches.
+ int global_ic_age() { return global_ic_age_; }
+
+ void AgeInlineCaches() {
+ global_ic_age_ = (global_ic_age_ + 1) & SharedFunctionInfo::ICAgeBits::kMax;
+ }
+
+ bool flush_monomorphic_ics() { return flush_monomorphic_ics_; }
+
+ int64_t amount_of_external_allocated_memory() {
+ return amount_of_external_allocated_memory_;
+ }
+
+ void DeoptMarkedAllocationSites();
+
+ bool MaximumSizeScavenge() { return maximum_size_scavenges_ > 0; }
+
+ bool DeoptMaybeTenuredAllocationSites() {
+ return new_space_.IsAtMaximumCapacity() && maximum_size_scavenges_ == 0;
+ }
+
+ // ObjectStats are kept in two arrays, counts and sizes. Related stats are
+ // stored in a contiguous linear buffer. Stats groups are stored one after
+ // another.
+ enum {
+ FIRST_CODE_KIND_SUB_TYPE = LAST_TYPE + 1,
+ FIRST_FIXED_ARRAY_SUB_TYPE =
+ FIRST_CODE_KIND_SUB_TYPE + Code::NUMBER_OF_KINDS,
+ FIRST_CODE_AGE_SUB_TYPE =
+ FIRST_FIXED_ARRAY_SUB_TYPE + LAST_FIXED_ARRAY_SUB_TYPE + 1,
+ OBJECT_STATS_COUNT = FIRST_CODE_AGE_SUB_TYPE + Code::kCodeAgeCount + 1
+ };
+
+ void RecordObjectStats(InstanceType type, size_t size) {
+ DCHECK(type <= LAST_TYPE);
+ object_counts_[type]++;
+ object_sizes_[type] += size;
+ }
+
+ void RecordCodeSubTypeStats(int code_sub_type, int code_age, size_t size) {
+ int code_sub_type_index = FIRST_CODE_KIND_SUB_TYPE + code_sub_type;
+ int code_age_index =
+ FIRST_CODE_AGE_SUB_TYPE + code_age - Code::kFirstCodeAge;
+ DCHECK(code_sub_type_index >= FIRST_CODE_KIND_SUB_TYPE &&
+ code_sub_type_index < FIRST_CODE_AGE_SUB_TYPE);
+ DCHECK(code_age_index >= FIRST_CODE_AGE_SUB_TYPE &&
+ code_age_index < OBJECT_STATS_COUNT);
+ object_counts_[code_sub_type_index]++;
+ object_sizes_[code_sub_type_index] += size;
+ object_counts_[code_age_index]++;
+ object_sizes_[code_age_index] += size;
+ }
+
+ void RecordFixedArraySubTypeStats(int array_sub_type, size_t size) {
+ DCHECK(array_sub_type <= LAST_FIXED_ARRAY_SUB_TYPE);
+ object_counts_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type]++;
+ object_sizes_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type] += size;
+ }
+
+ void CheckpointObjectStats();
+
+ // We don't use a LockGuard here since we want to lock the heap
+ // only when FLAG_concurrent_recompilation is true.
+ class RelocationLock {
+ public:
+ explicit RelocationLock(Heap* heap) : heap_(heap) {
+ heap_->relocation_mutex_.Lock();
+ }
+
+
+ ~RelocationLock() { heap_->relocation_mutex_.Unlock(); }
+
+ private:
+ Heap* heap_;
+ };
+
+ void AddWeakObjectToCodeDependency(Handle<Object> obj,
+ Handle<DependentCode> dep);
+
+ DependentCode* LookupWeakObjectToCodeDependency(Handle<Object> obj);
+
+ void InitializeWeakObjectToCodeTable() {
+ set_weak_object_to_code_table(undefined_value());
+ }
+
+ void EnsureWeakObjectToCodeTable();
+
+ static void FatalProcessOutOfMemory(const char* location,
+ bool take_snapshot = false);
+
+ // This event is triggered after successful allocation of a new object made
+ // by runtime. Allocations of target space for object evacuation do not
+ // trigger the event. In order to track ALL allocations one must turn off
+ // FLAG_inline_new and FLAG_use_allocation_folding.
+ inline void OnAllocationEvent(HeapObject* object, int size_in_bytes);
+
+ // This event is triggered after object is moved to a new place.
+ inline void OnMoveEvent(HeapObject* target, HeapObject* source,
+ int size_in_bytes);
+
+ protected:
+ // Methods made available to tests.
+
+ // Allocates a JS Map in the heap.
+ MUST_USE_RESULT AllocationResult
+ AllocateMap(InstanceType instance_type, int instance_size,
+ ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND);
+
+ // Allocates and initializes a new JavaScript object based on a
+ // constructor.
+ // If allocation_site is non-null, then a memento is emitted after the object
+ // that points to the site.
+ MUST_USE_RESULT AllocationResult
+ AllocateJSObject(JSFunction* constructor,
+ PretenureFlag pretenure = NOT_TENURED,
+ AllocationSite* allocation_site = NULL);
+
+ // Allocates and initializes a new JavaScript object based on a map.
+ // Passing an allocation site means that a memento will be created that
+ // points to the site.
+ MUST_USE_RESULT AllocationResult
+ AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure = NOT_TENURED,
+ bool alloc_props = true,
+ AllocationSite* allocation_site = NULL);
+
+ // Allocated a HeapNumber from value.
+ MUST_USE_RESULT AllocationResult
+ AllocateHeapNumber(double value, MutableMode mode = IMMUTABLE,
+ PretenureFlag pretenure = NOT_TENURED);
+
+ // Allocate a byte array of the specified length
+ MUST_USE_RESULT AllocationResult
+ AllocateByteArray(int length, PretenureFlag pretenure = NOT_TENURED);
+
+ // Copy the code and scope info part of the code object, but insert
+ // the provided data as the relocation information.
+ MUST_USE_RESULT AllocationResult
+ CopyCode(Code* code, Vector<byte> reloc_info);
+
+ MUST_USE_RESULT AllocationResult CopyCode(Code* code);
+
+ // Allocates a fixed array initialized with undefined values
+ MUST_USE_RESULT AllocationResult
+ AllocateFixedArray(int length, PretenureFlag pretenure = NOT_TENURED);
+
+ private:
+ Heap();
+
+ // The amount of external memory registered through the API kept alive
+ // by global handles
+ int64_t amount_of_external_allocated_memory_;
+
+ // Caches the amount of external memory registered at the last global gc.
+ int64_t amount_of_external_allocated_memory_at_last_global_gc_;
+
+ // This can be calculated directly from a pointer to the heap; however, it is
+ // more expedient to get at the isolate directly from within Heap methods.
+ Isolate* isolate_;
+
+ Object* roots_[kRootListLength];
+
+ size_t code_range_size_;
+ int reserved_semispace_size_;
+ int max_semi_space_size_;
+ int initial_semispace_size_;
+ intptr_t max_old_generation_size_;
+ intptr_t max_executable_size_;
+ intptr_t maximum_committed_;
+
+ // For keeping track of how much data has survived
+ // scavenge since last new space expansion.
+ int survived_since_last_expansion_;
+
+ // For keeping track on when to flush RegExp code.
+ int sweep_generation_;
+
+ int always_allocate_scope_depth_;
+
+ // For keeping track of context disposals.
+ int contexts_disposed_;
+
+ int global_ic_age_;
+
+ bool flush_monomorphic_ics_;
+
+ int scan_on_scavenge_pages_;
+
+ NewSpace new_space_;
+ OldSpace* old_pointer_space_;
+ OldSpace* old_data_space_;
+ OldSpace* code_space_;
+ MapSpace* map_space_;
+ CellSpace* cell_space_;
+ PropertyCellSpace* property_cell_space_;
+ LargeObjectSpace* lo_space_;
+ HeapState gc_state_;
+ int gc_post_processing_depth_;
+ Address new_space_top_after_last_gc_;
+
+ // Returns the amount of external memory registered since last global gc.
+ int64_t PromotedExternalMemorySize();
+
+ // How many "runtime allocations" happened.
+ uint32_t allocations_count_;
+
+ // Running hash over allocations performed.
+ uint32_t raw_allocations_hash_;
+
+ // Countdown counter, dumps allocation hash when 0.
+ uint32_t dump_allocations_hash_countdown_;
+
+ // How many mark-sweep collections happened.
+ unsigned int ms_count_;
+
+ // How many gc happened.
+ unsigned int gc_count_;
+
+ // For post mortem debugging.
+ static const int kRememberedUnmappedPages = 128;
+ int remembered_unmapped_pages_index_;
+ Address remembered_unmapped_pages_[kRememberedUnmappedPages];
+
+ // Total length of the strings we failed to flatten since the last GC.
+ int unflattened_strings_length_;
+
+#define ROOT_ACCESSOR(type, name, camel_name) \
+ inline void set_##name(type* value) { \
+ /* The deserializer makes use of the fact that these common roots are */ \
+ /* never in new space and never on a page that is being compacted. */ \
+ DCHECK(k##camel_name##RootIndex >= kOldSpaceRoots || !InNewSpace(value)); \
+ roots_[k##camel_name##RootIndex] = value; \
+ }
+ ROOT_LIST(ROOT_ACCESSOR)
+#undef ROOT_ACCESSOR
+
+#ifdef DEBUG
+ // If the --gc-interval flag is set to a positive value, this
+ // variable holds the value indicating the number of allocations
+ // remain until the next failure and garbage collection.
+ int allocation_timeout_;
+#endif // DEBUG
+
+ // Limit that triggers a global GC on the next (normally caused) GC. This
+ // is checked when we have already decided to do a GC to help determine
+ // which collector to invoke, before expanding a paged space in the old
+ // generation and on every allocation in large object space.
+ intptr_t old_generation_allocation_limit_;
+
+ // Indicates that an allocation has failed in the old generation since the
+ // last GC.
+ bool old_gen_exhausted_;
+
+ // Indicates that inline bump-pointer allocation has been globally disabled
+ // for all spaces. This is used to disable allocations in generated code.
+ bool inline_allocation_disabled_;
+
+ // Weak list heads, threaded through the objects.
+ // List heads are initilized lazily and contain the undefined_value at start.
+ Object* native_contexts_list_;
+ Object* array_buffers_list_;
+ Object* allocation_sites_list_;
+
+ // WeakHashTable that maps objects embedded in optimized code to dependent
+ // code list. It is initilized lazily and contains the undefined_value at
+ // start.
+ Object* weak_object_to_code_table_;
+
+ // List of encountered weak collections (JSWeakMap and JSWeakSet) during
+ // marking. It is initialized during marking, destroyed after marking and
+ // contains Smi(0) while marking is not active.
+ Object* encountered_weak_collections_;
+
+ StoreBufferRebuilder store_buffer_rebuilder_;
+
+ struct StringTypeTable {
+ InstanceType type;
+ int size;
+ RootListIndex index;
+ };
+
+ struct ConstantStringTable {
+ const char* contents;
+ RootListIndex index;
+ };
+
+ struct StructTable {
+ InstanceType type;
+ int size;
+ RootListIndex index;
+ };
+
+ static const StringTypeTable string_type_table[];
+ static const ConstantStringTable constant_string_table[];
+ static const StructTable struct_table[];
+
+ // The special hidden string which is an empty string, but does not match
+ // any string when looked up in properties.
+ String* hidden_string_;
+
+ // GC callback function, called before and after mark-compact GC.
+ // Allocations in the callback function are disallowed.
+ struct GCPrologueCallbackPair {
+ GCPrologueCallbackPair(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type, bool pass_isolate)
+ : callback(callback), gc_type(gc_type), pass_isolate_(pass_isolate) {}
+ bool operator==(const GCPrologueCallbackPair& pair) const {
+ return pair.callback == callback;
+ }
+ v8::Isolate::GCPrologueCallback callback;
+ GCType gc_type;
+ // TODO(dcarney): remove variable
+ bool pass_isolate_;
+ };
+ List<GCPrologueCallbackPair> gc_prologue_callbacks_;
+
+ struct GCEpilogueCallbackPair {
+ GCEpilogueCallbackPair(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type, bool pass_isolate)
+ : callback(callback), gc_type(gc_type), pass_isolate_(pass_isolate) {}
+ bool operator==(const GCEpilogueCallbackPair& pair) const {
+ return pair.callback == callback;
+ }
+ v8::Isolate::GCPrologueCallback callback;
+ GCType gc_type;
+ // TODO(dcarney): remove variable
+ bool pass_isolate_;
+ };
+ List<GCEpilogueCallbackPair> gc_epilogue_callbacks_;
+
+ // Support for computing object sizes during GC.
+ HeapObjectCallback gc_safe_size_of_old_object_;
+ static int GcSafeSizeOfOldObject(HeapObject* object);
+
+ // Update the GC state. Called from the mark-compact collector.
+ void MarkMapPointersAsEncoded(bool encoded) {
+ DCHECK(!encoded);
+ gc_safe_size_of_old_object_ = &GcSafeSizeOfOldObject;
+ }
+
+ // Code that should be run before and after each GC. Includes some
+ // reporting/verification activities when compiled with DEBUG set.
+ void GarbageCollectionPrologue();
+ void GarbageCollectionEpilogue();
+
+ // Pretenuring decisions are made based on feedback collected during new
+ // space evacuation. Note that between feedback collection and calling this
+ // method object in old space must not move.
+ // Right now we only process pretenuring feedback in high promotion mode.
+ void ProcessPretenuringFeedback();
+
+ // Checks whether a global GC is necessary
+ GarbageCollector SelectGarbageCollector(AllocationSpace space,
+ const char** reason);
+
+ // Make sure there is a filler value behind the top of the new space
+ // so that the GC does not confuse some unintialized/stale memory
+ // with the allocation memento of the object at the top
+ void EnsureFillerObjectAtTop();
+
+ // Ensure that we have swept all spaces in such a way that we can iterate
+ // over all objects. May cause a GC.
+ void MakeHeapIterable();
+
+ // Performs garbage collection operation.
+ // Returns whether there is a chance that another major GC could
+ // collect more garbage.
+ bool CollectGarbage(
+ GarbageCollector collector, const char* gc_reason,
+ const char* collector_reason,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ // Performs garbage collection
+ // Returns whether there is a chance another major GC could
+ // collect more garbage.
+ bool PerformGarbageCollection(
+ GarbageCollector collector,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ inline void UpdateOldSpaceLimits();
+
+ // Selects the proper allocation space depending on the given object
+ // size, pretenuring decision, and preferred old-space.
+ static AllocationSpace SelectSpace(int object_size,
+ AllocationSpace preferred_old_space,
+ PretenureFlag pretenure) {
+ DCHECK(preferred_old_space == OLD_POINTER_SPACE ||
+ preferred_old_space == OLD_DATA_SPACE);
+ if (object_size > Page::kMaxRegularHeapObjectSize) return LO_SPACE;
+ return (pretenure == TENURED) ? preferred_old_space : NEW_SPACE;
+ }
+
+ // Allocate an uninitialized object. The memory is non-executable if the
+ // hardware and OS allow. This is the single choke-point for allocations
+ // performed by the runtime and should not be bypassed (to extend this to
+ // inlined allocations, use the Heap::DisableInlineAllocation() support).
+ MUST_USE_RESULT inline AllocationResult AllocateRaw(
+ int size_in_bytes, AllocationSpace space, AllocationSpace retry_space);
+
+ // Allocates a heap object based on the map.
+ MUST_USE_RESULT AllocationResult
+ Allocate(Map* map, AllocationSpace space,
+ AllocationSite* allocation_site = NULL);
+
+ // Allocates a partial map for bootstrapping.
+ MUST_USE_RESULT AllocationResult
+ AllocatePartialMap(InstanceType instance_type, int instance_size);
+
+ // Initializes a JSObject based on its map.
+ void InitializeJSObjectFromMap(JSObject* obj, FixedArray* properties,
+ Map* map);
+ void InitializeAllocationMemento(AllocationMemento* memento,
+ AllocationSite* allocation_site);
+
+ // Allocate a block of memory in the given space (filled with a filler).
+ // Used as a fall-back for generated code when the space is full.
+ MUST_USE_RESULT AllocationResult
+ AllocateFillerObject(int size, bool double_align, AllocationSpace space);
+
+ // Allocate an uninitialized fixed array.
+ MUST_USE_RESULT AllocationResult
+ AllocateRawFixedArray(int length, PretenureFlag pretenure);
+
+ // Allocate an uninitialized fixed double array.
+ MUST_USE_RESULT AllocationResult
+ AllocateRawFixedDoubleArray(int length, PretenureFlag pretenure);
+
+ // Allocate an initialized fixed array with the given filler value.
+ MUST_USE_RESULT AllocationResult
+ AllocateFixedArrayWithFiller(int length, PretenureFlag pretenure,
+ Object* filler);
+
+ // Allocate and partially initializes a String. There are two String
+ // encodings: one-byte and two-byte. These functions allocate a string of
+ // the given length and set its map and length fields. The characters of
+ // the string are uninitialized.
+ MUST_USE_RESULT AllocationResult
+ AllocateRawOneByteString(int length, PretenureFlag pretenure);
+ MUST_USE_RESULT AllocationResult
+ AllocateRawTwoByteString(int length, PretenureFlag pretenure);
+
+ bool CreateInitialMaps();
+ void CreateInitialObjects();
+
+ // Allocates an internalized string in old space based on the character
+ // stream.
+ MUST_USE_RESULT inline AllocationResult AllocateInternalizedStringFromUtf8(
+ Vector<const char> str, int chars, uint32_t hash_field);
+
+ MUST_USE_RESULT inline AllocationResult AllocateOneByteInternalizedString(
+ Vector<const uint8_t> str, uint32_t hash_field);
+
+ MUST_USE_RESULT inline AllocationResult AllocateTwoByteInternalizedString(
+ Vector<const uc16> str, uint32_t hash_field);
+
+ template <bool is_one_byte, typename T>
+ MUST_USE_RESULT AllocationResult
+ AllocateInternalizedStringImpl(T t, int chars, uint32_t hash_field);
+
+ template <typename T>
+ MUST_USE_RESULT inline AllocationResult AllocateInternalizedStringImpl(
+ T t, int chars, uint32_t hash_field);
+
+ // Allocates an uninitialized fixed array. It must be filled by the caller.
+ MUST_USE_RESULT AllocationResult AllocateUninitializedFixedArray(int length);
+
+ // Make a copy of src and return it. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT inline AllocationResult CopyFixedArray(FixedArray* src);
+
+ // Make a copy of src, set the map, and return the copy. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT AllocationResult
+ CopyFixedArrayWithMap(FixedArray* src, Map* map);
+
+ // Make a copy of src and return it. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT inline AllocationResult CopyFixedDoubleArray(
+ FixedDoubleArray* src);
+
+ // Make a copy of src and return it. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT inline AllocationResult CopyConstantPoolArray(
+ ConstantPoolArray* src);
+
+
+ // Computes a single character string where the character has code.
+ // A cache is used for one-byte (Latin1) codes.
+ MUST_USE_RESULT AllocationResult
+ LookupSingleCharacterStringFromCode(uint16_t code);
+
+ // Allocate a symbol in old space.
+ MUST_USE_RESULT AllocationResult AllocateSymbol();
+
+ // Make a copy of src, set the map, and return the copy.
+ MUST_USE_RESULT AllocationResult
+ CopyConstantPoolArrayWithMap(ConstantPoolArray* src, Map* map);
+
+ MUST_USE_RESULT AllocationResult AllocateConstantPoolArray(
+ const ConstantPoolArray::NumberOfEntries& small);
+
+ MUST_USE_RESULT AllocationResult AllocateExtendedConstantPoolArray(
+ const ConstantPoolArray::NumberOfEntries& small,
+ const ConstantPoolArray::NumberOfEntries& extended);
+
+ // Allocates an external array of the specified length and type.
+ MUST_USE_RESULT AllocationResult
+ AllocateExternalArray(int length, ExternalArrayType array_type,
+ void* external_pointer, PretenureFlag pretenure);
+
+ // Allocates a fixed typed array of the specified length and type.
+ MUST_USE_RESULT AllocationResult
+ AllocateFixedTypedArray(int length, ExternalArrayType array_type,
+ PretenureFlag pretenure);
+
+ // Make a copy of src and return it.
+ MUST_USE_RESULT AllocationResult CopyAndTenureFixedCOWArray(FixedArray* src);
+
+ // Make a copy of src, set the map, and return the copy.
+ MUST_USE_RESULT AllocationResult
+ CopyFixedDoubleArrayWithMap(FixedDoubleArray* src, Map* map);
+
+ // Allocates a fixed double array with uninitialized values. Returns
+ MUST_USE_RESULT AllocationResult AllocateUninitializedFixedDoubleArray(
+ int length, PretenureFlag pretenure = NOT_TENURED);
+
+ // These five Create*EntryStub functions are here and forced to not be inlined
+ // because of a gcc-4.4 bug that assigns wrong vtable entries.
+ NO_INLINE(void CreateJSEntryStub());
+ NO_INLINE(void CreateJSConstructEntryStub());
+
+ void CreateFixedStubs();
+
+ // Allocate empty fixed array.
+ MUST_USE_RESULT AllocationResult AllocateEmptyFixedArray();
+
+ // Allocate empty external array of given type.
+ MUST_USE_RESULT AllocationResult
+ AllocateEmptyExternalArray(ExternalArrayType array_type);
+
+ // Allocate empty fixed typed array of given type.
+ MUST_USE_RESULT AllocationResult
+ AllocateEmptyFixedTypedArray(ExternalArrayType array_type);
+
+ // Allocate empty constant pool array.
+ MUST_USE_RESULT AllocationResult AllocateEmptyConstantPoolArray();
+
+ // Allocate a tenured simple cell.
+ MUST_USE_RESULT AllocationResult AllocateCell(Object* value);
+
+ // Allocate a tenured JS global property cell initialized with the hole.
+ MUST_USE_RESULT AllocationResult AllocatePropertyCell();
+
+ // Allocates a new utility object in the old generation.
+ MUST_USE_RESULT AllocationResult AllocateStruct(InstanceType type);
+
+ // Allocates a new foreign object.
+ MUST_USE_RESULT AllocationResult
+ AllocateForeign(Address address, PretenureFlag pretenure = NOT_TENURED);
+
+ MUST_USE_RESULT AllocationResult
+ AllocateCode(int object_size, bool immovable);
+
+ MUST_USE_RESULT AllocationResult InternalizeStringWithKey(HashTableKey* key);
+
+ MUST_USE_RESULT AllocationResult InternalizeString(String* str);
+
+ // Performs a minor collection in new generation.
+ void Scavenge();
+
+ // Commits from space if it is uncommitted.
+ void EnsureFromSpaceIsCommitted();
+
+ // Uncommit unused semi space.
+ bool UncommitFromSpace() { return new_space_.UncommitFromSpace(); }
+
+ // Fill in bogus values in from space
+ void ZapFromSpace();
+
+ static String* UpdateNewSpaceReferenceInExternalStringTableEntry(
+ Heap* heap, Object** pointer);
+
+ Address DoScavenge(ObjectVisitor* scavenge_visitor, Address new_space_front);
+ static void ScavengeStoreBufferCallback(Heap* heap, MemoryChunk* page,
+ StoreBufferEvent event);
+
+ // Performs a major collection in the whole heap.
+ void MarkCompact();
+
+ // Code to be run before and after mark-compact.
+ void MarkCompactPrologue();
+
+ void ProcessNativeContexts(WeakObjectRetainer* retainer);
+ void ProcessArrayBuffers(WeakObjectRetainer* retainer);
+ void ProcessAllocationSites(WeakObjectRetainer* retainer);
+
+ // Deopts all code that contains allocation instruction which are tenured or
+ // not tenured. Moreover it clears the pretenuring allocation site statistics.
+ void ResetAllAllocationSitesDependentCode(PretenureFlag flag);
+
+ // Evaluates local pretenuring for the old space and calls
+ // ResetAllTenuredAllocationSitesDependentCode if too many objects died in
+ // the old space.
+ void EvaluateOldSpaceLocalPretenuring(uint64_t size_of_objects_before_gc);
+
+ // Called on heap tear-down.
+ void TearDownArrayBuffers();
+
+ // Record statistics before and after garbage collection.
+ void ReportStatisticsBeforeGC();
+ void ReportStatisticsAfterGC();
+
+ // Slow part of scavenge object.
+ static void ScavengeObjectSlow(HeapObject** p, HeapObject* object);
+
+ // Total RegExp code ever generated
+ double total_regexp_code_generated_;
+
+ GCTracer tracer_;
+
+ // Creates and installs the full-sized number string cache.
+ int FullSizeNumberStringCacheLength();
+ // Flush the number to string cache.
+ void FlushNumberStringCache();
+
+ // Sets used allocation sites entries to undefined.
+ void FlushAllocationSitesScratchpad();
+
+ // Initializes the allocation sites scratchpad with undefined values.
+ void InitializeAllocationSitesScratchpad();
+
+ // Adds an allocation site to the scratchpad if there is space left.
+ void AddAllocationSiteToScratchpad(AllocationSite* site,
+ ScratchpadSlotMode mode);
+
+ void UpdateSurvivalStatistics(int start_new_space_size);
+
+ static const int kYoungSurvivalRateHighThreshold = 90;
+ static const int kYoungSurvivalRateAllowedDeviation = 15;
+
+ static const int kOldSurvivalRateLowThreshold = 10;
+
+ int high_survival_rate_period_length_;
+ intptr_t promoted_objects_size_;
+ double promotion_rate_;
+ intptr_t semi_space_copied_object_size_;
+ double semi_space_copied_rate_;
+ int nodes_died_in_new_space_;
+ int nodes_copied_in_new_space_;
+ int nodes_promoted_;
+
+ // This is the pretenuring trigger for allocation sites that are in maybe
+ // tenure state. When we switched to the maximum new space size we deoptimize
+ // the code that belongs to the allocation site and derive the lifetime
+ // of the allocation site.
+ unsigned int maximum_size_scavenges_;
+
+ // TODO(hpayer): Allocation site pretenuring may make this method obsolete.
+ // Re-visit incremental marking heuristics.
+ bool IsHighSurvivalRate() { return high_survival_rate_period_length_ > 0; }
+
+ void SelectScavengingVisitorsTable();
+
+ void IdleMarkCompact(const char* message);
+
+ void AdvanceIdleIncrementalMarking(intptr_t step_size);
+
+ bool WorthActivatingIncrementalMarking();
+
+ void ClearObjectStats(bool clear_last_time_stats = false);
+
+ void set_weak_object_to_code_table(Object* value) {
+ DCHECK(!InNewSpace(value));
+ weak_object_to_code_table_ = value;
+ }
+
+ Object** weak_object_to_code_table_address() {
+ return &weak_object_to_code_table_;
+ }
+
+ inline void UpdateAllocationsHash(HeapObject* object);
+ inline void UpdateAllocationsHash(uint32_t value);
+ inline void PrintAlloctionsHash();
+
+ static const int kInitialStringTableSize = 2048;
+ static const int kInitialEvalCacheSize = 64;
+ static const int kInitialNumberStringCacheSize = 256;
+
+ // Object counts and used memory by InstanceType
+ size_t object_counts_[OBJECT_STATS_COUNT];
+ size_t object_counts_last_time_[OBJECT_STATS_COUNT];
+ size_t object_sizes_[OBJECT_STATS_COUNT];
+ size_t object_sizes_last_time_[OBJECT_STATS_COUNT];
+
+ // Maximum GC pause.
+ double max_gc_pause_;
+
+ // Total time spent in GC.
+ double total_gc_time_ms_;
+
+ // Maximum size of objects alive after GC.
+ intptr_t max_alive_after_gc_;
+
+ // Minimal interval between two subsequent collections.
+ double min_in_mutator_;
+
+ // Cumulative GC time spent in marking
+ double marking_time_;
+
+ // Cumulative GC time spent in sweeping
+ double sweeping_time_;
+
+ MarkCompactCollector mark_compact_collector_;
+
+ StoreBuffer store_buffer_;
+
+ Marking marking_;
+
+ IncrementalMarking incremental_marking_;
+
+ GCIdleTimeHandler gc_idle_time_handler_;
+ unsigned int gc_count_at_last_idle_gc_;
+
+ // These two counters are monotomically increasing and never reset.
+ size_t full_codegen_bytes_generated_;
+ size_t crankshaft_codegen_bytes_generated_;
+
+ // If the --deopt_every_n_garbage_collections flag is set to a positive value,
+ // this variable holds the number of garbage collections since the last
+ // deoptimization triggered by garbage collection.
+ int gcs_since_last_deopt_;
+
+#ifdef VERIFY_HEAP
+ int no_weak_object_verification_scope_depth_;
+#endif
+
+ static const int kAllocationSiteScratchpadSize = 256;
+ int allocation_sites_scratchpad_length_;
+
+ static const int kMaxMarkCompactsInIdleRound = 7;
+ static const int kIdleScavengeThreshold = 5;
+
+ // Shared state read by the scavenge collector and set by ScavengeObject.
+ PromotionQueue promotion_queue_;
+
+ // Flag is set when the heap has been configured. The heap can be repeatedly
+ // configured through the API until it is set up.
+ bool configured_;
+
+ ExternalStringTable external_string_table_;
+
+ VisitorDispatchTable<ScavengingCallback> scavenging_visitors_table_;
+
+ MemoryChunk* chunks_queued_for_free_;
+
+ base::Mutex relocation_mutex_;
+
+ int gc_callbacks_depth_;
+
+ friend class AlwaysAllocateScope;
+ friend class Factory;
+ friend class GCCallbacksScope;
+ friend class GCTracer;
+ friend class HeapIterator;
+ friend class Isolate;
+ friend class MarkCompactCollector;
+ friend class MarkCompactMarkingVisitor;
+ friend class MapCompact;
+#ifdef VERIFY_HEAP
+ friend class NoWeakObjectVerificationScope;
+#endif
+ friend class Page;
+
+ DISALLOW_COPY_AND_ASSIGN(Heap);
+};
+
+
+class HeapStats {
+ public:
+ static const int kStartMarker = 0xDECADE00;
+ static const int kEndMarker = 0xDECADE01;
+
+ int* start_marker; // 0
+ int* new_space_size; // 1
+ int* new_space_capacity; // 2
+ intptr_t* old_pointer_space_size; // 3
+ intptr_t* old_pointer_space_capacity; // 4
+ intptr_t* old_data_space_size; // 5
+ intptr_t* old_data_space_capacity; // 6
+ intptr_t* code_space_size; // 7
+ intptr_t* code_space_capacity; // 8
+ intptr_t* map_space_size; // 9
+ intptr_t* map_space_capacity; // 10
+ intptr_t* cell_space_size; // 11
+ intptr_t* cell_space_capacity; // 12
+ intptr_t* lo_space_size; // 13
+ int* global_handle_count; // 14
+ int* weak_global_handle_count; // 15
+ int* pending_global_handle_count; // 16
+ int* near_death_global_handle_count; // 17
+ int* free_global_handle_count; // 18
+ intptr_t* memory_allocator_size; // 19
+ intptr_t* memory_allocator_capacity; // 20
+ int* objects_per_type; // 21
+ int* size_per_type; // 22
+ int* os_error; // 23
+ int* end_marker; // 24
+ intptr_t* property_cell_space_size; // 25
+ intptr_t* property_cell_space_capacity; // 26
+};
+
+
+class AlwaysAllocateScope {
+ public:
+ explicit inline AlwaysAllocateScope(Isolate* isolate);
+ inline ~AlwaysAllocateScope();
+
+ private:
+ // Implicitly disable artificial allocation failures.
+ Heap* heap_;
+ DisallowAllocationFailure daf_;
+};
+
+
+#ifdef VERIFY_HEAP
+class NoWeakObjectVerificationScope {
+ public:
+ inline NoWeakObjectVerificationScope();
+ inline ~NoWeakObjectVerificationScope();
+};
+#endif
+
+
+class GCCallbacksScope {
+ public:
+ explicit inline GCCallbacksScope(Heap* heap);
+ inline ~GCCallbacksScope();
+
+ inline bool CheckReenter();
+
+ private:
+ Heap* heap_;
+};
+
+
+// Visitor class to verify interior pointers in spaces that do not contain
+// or care about intergenerational references. All heap object pointers have to
+// point into the heap to a location that has a map pointer at its first word.
+// Caveat: Heap::Contains is an approximation because it can return true for
+// objects in a heap space but above the allocation pointer.
+class VerifyPointersVisitor : public ObjectVisitor {
+ public:
+ inline void VisitPointers(Object** start, Object** end);
+};
+
+
+// Verify that all objects are Smis.
+class VerifySmisVisitor : public ObjectVisitor {
+ public:
+ inline void VisitPointers(Object** start, Object** end);
+};
+
+
+// Space iterator for iterating over all spaces of the heap. Returns each space
+// in turn, and null when it is done.
+class AllSpaces BASE_EMBEDDED {
+ public:
+ explicit AllSpaces(Heap* heap) : heap_(heap), counter_(FIRST_SPACE) {}
+ Space* next();
+
+ private:
+ Heap* heap_;
+ int counter_;
+};
+
+
+// Space iterator for iterating over all old spaces of the heap: Old pointer
+// space, old data space and code space. Returns each space in turn, and null
+// when it is done.
+class OldSpaces BASE_EMBEDDED {
+ public:
+ explicit OldSpaces(Heap* heap) : heap_(heap), counter_(OLD_POINTER_SPACE) {}
+ OldSpace* next();
+
+ private:
+ Heap* heap_;
+ int counter_;
+};
+
+
+// Space iterator for iterating over all the paged spaces of the heap: Map
+// space, old pointer space, old data space, code space and cell space. Returns
+// each space in turn, and null when it is done.
+class PagedSpaces BASE_EMBEDDED {
+ public:
+ explicit PagedSpaces(Heap* heap) : heap_(heap), counter_(OLD_POINTER_SPACE) {}
+ PagedSpace* next();
+
+ private:
+ Heap* heap_;
+ int counter_;
+};
+
+
+// Space iterator for iterating over all spaces of the heap.
+// For each space an object iterator is provided. The deallocation of the
+// returned object iterators is handled by the space iterator.
+class SpaceIterator : public Malloced {
+ public:
+ explicit SpaceIterator(Heap* heap);
+ SpaceIterator(Heap* heap, HeapObjectCallback size_func);
+ virtual ~SpaceIterator();
+
+ bool has_next();
+ ObjectIterator* next();
+
+ private:
+ ObjectIterator* CreateIterator();
+
+ Heap* heap_;
+ int current_space_; // from enum AllocationSpace.
+ ObjectIterator* iterator_; // object iterator for the current space.
+ HeapObjectCallback size_func_;
+};
+
+
+// A HeapIterator provides iteration over the whole heap. It
+// aggregates the specific iterators for the different spaces as
+// these can only iterate over one space only.
+//
+// HeapIterator ensures there is no allocation during its lifetime
+// (using an embedded DisallowHeapAllocation instance).
+//
+// HeapIterator can skip free list nodes (that is, de-allocated heap
+// objects that still remain in the heap). As implementation of free
+// nodes filtering uses GC marks, it can't be used during MS/MC GC
+// phases. Also, it is forbidden to interrupt iteration in this mode,
+// as this will leave heap objects marked (and thus, unusable).
+class HeapObjectsFilter;
+
+class HeapIterator BASE_EMBEDDED {
+ public:
+ enum HeapObjectsFiltering { kNoFiltering, kFilterUnreachable };
+
+ explicit HeapIterator(Heap* heap);
+ HeapIterator(Heap* heap, HeapObjectsFiltering filtering);
+ ~HeapIterator();
+
+ HeapObject* next();
+ void reset();
+
+ private:
+ struct MakeHeapIterableHelper {
+ explicit MakeHeapIterableHelper(Heap* heap) { heap->MakeHeapIterable(); }
+ };
+
+ // Perform the initialization.
+ void Init();
+ // Perform all necessary shutdown (destruction) work.
+ void Shutdown();
+ HeapObject* NextObject();
+
+ MakeHeapIterableHelper make_heap_iterable_helper_;
+ DisallowHeapAllocation no_heap_allocation_;
+ Heap* heap_;
+ HeapObjectsFiltering filtering_;
+ HeapObjectsFilter* filter_;
+ // Space iterator for iterating all the spaces.
+ SpaceIterator* space_iterator_;
+ // Object iterator for the space currently being iterated.
+ ObjectIterator* object_iterator_;
+};
+
+
+// Cache for mapping (map, property name) into field offset.
+// Cleared at startup and prior to mark sweep collection.
+class KeyedLookupCache {
+ public:
+ // Lookup field offset for (map, name). If absent, -1 is returned.
+ int Lookup(Handle<Map> map, Handle<Name> name);
+
+ // Update an element in the cache.
+ void Update(Handle<Map> map, Handle<Name> name, int field_offset);
+
+ // Clear the cache.
+ void Clear();
+
+ static const int kLength = 256;
+ static const int kCapacityMask = kLength - 1;
+ static const int kMapHashShift = 5;
+ static const int kHashMask = -4; // Zero the last two bits.
+ static const int kEntriesPerBucket = 4;
+ static const int kEntryLength = 2;
+ static const int kMapIndex = 0;
+ static const int kKeyIndex = 1;
+ static const int kNotFound = -1;
+
+ // kEntriesPerBucket should be a power of 2.
+ STATIC_ASSERT((kEntriesPerBucket & (kEntriesPerBucket - 1)) == 0);
+ STATIC_ASSERT(kEntriesPerBucket == -kHashMask);
+
+ private:
+ KeyedLookupCache() {
+ for (int i = 0; i < kLength; ++i) {
+ keys_[i].map = NULL;
+ keys_[i].name = NULL;
+ field_offsets_[i] = kNotFound;
+ }
+ }
+
+ static inline int Hash(Handle<Map> map, Handle<Name> name);
+
+ // Get the address of the keys and field_offsets arrays. Used in
+ // generated code to perform cache lookups.
+ Address keys_address() { return reinterpret_cast<Address>(&keys_); }
+
+ Address field_offsets_address() {
+ return reinterpret_cast<Address>(&field_offsets_);
+ }
+
+ struct Key {
+ Map* map;
+ Name* name;
+ };
+
+ Key keys_[kLength];
+ int field_offsets_[kLength];
+
+ friend class ExternalReference;
+ friend class Isolate;
+ DISALLOW_COPY_AND_ASSIGN(KeyedLookupCache);
+};
+
+
+// Cache for mapping (map, property name) into descriptor index.
+// The cache contains both positive and negative results.
+// Descriptor index equals kNotFound means the property is absent.
+// Cleared at startup and prior to any gc.
+class DescriptorLookupCache {
+ public:
+ // Lookup descriptor index for (map, name).
+ // If absent, kAbsent is returned.
+ int Lookup(Map* source, Name* name) {
+ if (!name->IsUniqueName()) return kAbsent;
+ int index = Hash(source, name);
+ Key& key = keys_[index];
+ if ((key.source == source) && (key.name == name)) return results_[index];
+ return kAbsent;
+ }
+
+ // Update an element in the cache.
+ void Update(Map* source, Name* name, int result) {
+ DCHECK(result != kAbsent);
+ if (name->IsUniqueName()) {
+ int index = Hash(source, name);
+ Key& key = keys_[index];
+ key.source = source;
+ key.name = name;
+ results_[index] = result;
+ }
+ }
+
+ // Clear the cache.
+ void Clear();
+
+ static const int kAbsent = -2;
+
+ private:
+ DescriptorLookupCache() {
+ for (int i = 0; i < kLength; ++i) {
+ keys_[i].source = NULL;
+ keys_[i].name = NULL;
+ results_[i] = kAbsent;
+ }
+ }
+
+ static int Hash(Object* source, Name* name) {
+ // Uses only lower 32 bits if pointers are larger.
+ uint32_t source_hash =
+ static_cast<uint32_t>(reinterpret_cast<uintptr_t>(source)) >>
+ kPointerSizeLog2;
+ uint32_t name_hash =
+ static_cast<uint32_t>(reinterpret_cast<uintptr_t>(name)) >>
+ kPointerSizeLog2;
+ return (source_hash ^ name_hash) % kLength;
+ }
+
+ static const int kLength = 64;
+ struct Key {
+ Map* source;
+ Name* name;
+ };
+
+ Key keys_[kLength];
+ int results_[kLength];
+
+ friend class Isolate;
+ DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache);
+};
+
+
+class RegExpResultsCache {
+ public:
+ enum ResultsCacheType { REGEXP_MULTIPLE_INDICES, STRING_SPLIT_SUBSTRINGS };
+
+ // Attempt to retrieve a cached result. On failure, 0 is returned as a Smi.
+ // On success, the returned result is guaranteed to be a COW-array.
+ static Object* Lookup(Heap* heap, String* key_string, Object* key_pattern,
+ ResultsCacheType type);
+ // Attempt to add value_array to the cache specified by type. On success,
+ // value_array is turned into a COW-array.
+ static void Enter(Isolate* isolate, Handle<String> key_string,
+ Handle<Object> key_pattern, Handle<FixedArray> value_array,
+ ResultsCacheType type);
+ static void Clear(FixedArray* cache);
+ static const int kRegExpResultsCacheSize = 0x100;
+
+ private:
+ static const int kArrayEntriesPerCacheEntry = 4;
+ static const int kStringOffset = 0;
+ static const int kPatternOffset = 1;
+ static const int kArrayOffset = 2;
+};
+
+
+// Abstract base class for checking whether a weak object should be retained.
+class WeakObjectRetainer {
+ public:
+ virtual ~WeakObjectRetainer() {}
+
+ // Return whether this object should be retained. If NULL is returned the
+ // object has no references. Otherwise the address of the retained object
+ // should be returned as in some GC situations the object has been moved.
+ virtual Object* RetainAs(Object* object) = 0;
+};
+
+
+// Intrusive object marking uses least significant bit of
+// heap object's map word to mark objects.
+// Normally all map words have least significant bit set
+// because they contain tagged map pointer.
+// If the bit is not set object is marked.
+// All objects should be unmarked before resuming
+// JavaScript execution.
+class IntrusiveMarking {
+ public:
+ static bool IsMarked(HeapObject* object) {
+ return (object->map_word().ToRawValue() & kNotMarkedBit) == 0;
+ }
+
+ static void ClearMark(HeapObject* object) {
+ uintptr_t map_word = object->map_word().ToRawValue();
+ object->set_map_word(MapWord::FromRawValue(map_word | kNotMarkedBit));
+ DCHECK(!IsMarked(object));
+ }
+
+ static void SetMark(HeapObject* object) {
+ uintptr_t map_word = object->map_word().ToRawValue();
+ object->set_map_word(MapWord::FromRawValue(map_word & ~kNotMarkedBit));
+ DCHECK(IsMarked(object));
+ }
+
+ static Map* MapOfMarkedObject(HeapObject* object) {
+ uintptr_t map_word = object->map_word().ToRawValue();
+ return MapWord::FromRawValue(map_word | kNotMarkedBit).ToMap();
+ }
+
+ static int SizeOfMarkedObject(HeapObject* object) {
+ return object->SizeFromMap(MapOfMarkedObject(object));
+ }
+
+ private:
+ static const uintptr_t kNotMarkedBit = 0x1;
+ STATIC_ASSERT((kHeapObjectTag & kNotMarkedBit) != 0); // NOLINT
+};
+
+
+#ifdef DEBUG
+// Helper class for tracing paths to a search target Object from all roots.
+// The TracePathFrom() method can be used to trace paths from a specific
+// object to the search target object.
+class PathTracer : public ObjectVisitor {
+ public:
+ enum WhatToFind {
+ FIND_ALL, // Will find all matches.
+ FIND_FIRST // Will stop the search after first match.
+ };
+
+ // Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
+ static const int kMarkTag = 2;
+
+ // For the WhatToFind arg, if FIND_FIRST is specified, tracing will stop
+ // after the first match. If FIND_ALL is specified, then tracing will be
+ // done for all matches.
+ PathTracer(Object* search_target, WhatToFind what_to_find,
+ VisitMode visit_mode)
+ : search_target_(search_target),
+ found_target_(false),
+ found_target_in_trace_(false),
+ what_to_find_(what_to_find),
+ visit_mode_(visit_mode),
+ object_stack_(20),
+ no_allocation() {}
+
+ virtual void VisitPointers(Object** start, Object** end);
+
+ void Reset();
+ void TracePathFrom(Object** root);
+
+ bool found() const { return found_target_; }
+
+ static Object* const kAnyGlobalObject;
+
+ protected:
+ class MarkVisitor;
+ class UnmarkVisitor;
+
+ void MarkRecursively(Object** p, MarkVisitor* mark_visitor);
+ void UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor);
+ virtual void ProcessResults();
+
+ Object* search_target_;
+ bool found_target_;
+ bool found_target_in_trace_;
+ WhatToFind what_to_find_;
+ VisitMode visit_mode_;
+ List<Object*> object_stack_;
+
+ DisallowHeapAllocation no_allocation; // i.e. no gc allowed.
+
+ private:
+ DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
+};
+#endif // DEBUG
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_HEAP_H_