Move a bunch of GC related files to heap/ subdirectory

src/heap.h

-// 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_H_
-#define V8_HEAP_H_
-
-#include <cmath>
-
-#include "src/allocation.h"
-#include "src/assert-scope.h"
-#include "src/counters.h"
-#include "src/gc-tracer.h"
-#include "src/globals.h"
-#include "src/incremental-marking.h"
-#include "src/list.h"
-#include "src/mark-compact.h"
-#include "src/objects-visiting.h"
-#include "src/spaces.h"
-#include "src/splay-tree-inl.h"
-#include "src/store-buffer.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, ascii_string_map, AsciiStringMap)                                     \
-  V(Map, cons_string_map, ConsStringMap)                                       \
-  V(Map, cons_ascii_string_map, ConsAsciiStringMap)                            \
-  V(Map, sliced_string_map, SlicedStringMap)                                   \
-  V(Map, sliced_ascii_string_map, SlicedAsciiStringMap)                        \
-  V(Map, external_string_map, ExternalStringMap)                               \
-  V(Map, external_string_with_one_byte_data_map,                               \
-    ExternalStringWithOneByteDataMap)                                          \
-  V(Map, external_ascii_string_map, ExternalAsciiStringMap)                    \
-  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, ascii_internalized_string_map, AsciiInternalizedStringMap)            \
-  V(Map, external_internalized_string_map, ExternalInternalizedStringMap)      \
-  V(Map, external_internalized_string_with_one_byte_data_map,                  \
-    ExternalInternalizedStringWithOneByteDataMap)                              \
-  V(Map, external_ascii_internalized_string_map,                               \
-    ExternalAsciiInternalizedStringMap)                                        \
-  V(Map, short_external_internalized_string_map,                               \
-    ShortExternalInternalizedStringMap)                                        \
-  V(Map, short_external_internalized_string_with_one_byte_data_map,            \
-    ShortExternalInternalizedStringWithOneByteDataMap)                         \
-  V(Map, short_external_ascii_internalized_string_map,                         \
-    ShortExternalAsciiInternalizedStringMap)                                   \
-  V(Map, short_external_ascii_string_map, ShortExternalAsciiStringMap)         \
-  V(Map, undetectable_string_map, UndetectableStringMap)                       \
-  V(Map, undetectable_ascii_string_map, UndetectableAsciiStringMap)            \
-  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, stack_trace_symbol, StackTraceSymbol)                              \
-  V(Symbol, detailed_stack_trace_symbol, DetailedStackTraceSymbol)             \
-  V(Symbol, normal_ic_symbol, NormalICSymbol)                                  \
-  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(Array_string, "Array")                                         \
-  V(Object_string, "Object")                                       \
-  V(proto_string, "__proto__")                                     \
-  V(arguments_string, "arguments")                                 \
-  V(Arguments_string, "Arguments")                                 \
-  V(call_string, "call")                                           \
-  V(apply_string, "apply")                                         \
-  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(length_string, "length")                                       \
-  V(name_string, "name")                                           \
-  V(null_string, "null")                                           \
-  V(number_string, "number")                                       \
-  V(Number_string, "Number")                                       \
-  V(nan_string, "NaN")                                             \
-  V(RegExp_string, "RegExp")                                       \
-  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(input_string, "input")                                         \
-  V(index_string, "index")                                         \
-  V(last_index_string, "lastIndex")                                \
-  V(object_string, "object")                                       \
-  V(literals_string, "literals")                                   \
-  V(prototype_string, "prototype")                                 \
-  V(string_string, "string")                                       \
-  V(String_string, "String")                                       \
-  V(symbol_string, "symbol")                                       \
-  V(Symbol_string, "Symbol")                                       \
-  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(to_string_string, "toString")                                  \
-  V(char_at_string, "CharAt")                                      \
-  V(undefined_string, "undefined")                                 \
-  V(value_of_string, "valueOf")                                    \
-  V(stack_string, "stack")                                         \
-  V(toJSON_string, "toJSON")                                       \
-  V(InitializeVarGlobal_string, "InitializeVarGlobal")             \
-  V(InitializeConstGlobal_string, "InitializeConstGlobal")         \
-  V(KeyedLoadMonomorphic_string, "KeyedLoadMonomorphic")           \
-  V(KeyedStoreMonomorphic_string, "KeyedStoreMonomorphic")         \
-  V(stack_overflow_string, "kStackOverflowBoilerplate")            \
-  V(illegal_access_string, "illegal access")                       \
-  V(get_string, "get")                                             \
-  V(set_string, "set")                                             \
-  V(map_field_string, "%map")                                      \
-  V(elements_field_string, "%elements")                            \
-  V(length_field_string, "%length")                                \
-  V(cell_value_string, "%cell_value")                              \
-  V(function_class_string, "Function")                             \
-  V(illegal_argument_string, "illegal argument")                   \
-  V(space_string, " ")                                             \
-  V(exec_string, "exec")                                           \
-  V(zero_string, "0")                                              \
-  V(global_eval_string, "GlobalEval")                              \
-  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(buffer_string, "buffer")                                       \
-  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;
-  }
-
-  inline void ActivateGuardIfOnTheSamePage();
-
-  Page* GetHeadPage() {
-    return Page::FromAllocationTop(reinterpret_cast<Address>(rear_));
-  }
-
-  void SetNewLimit(Address limit) {
-    if (!guard_) {
-      return;
-    }
-
-    DCHECK(GetHeadPage() == Page::FromAllocationTop(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_;
-
-  bool guard_;
-
-  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 shortening objects.
-  void CreateFillerObjectAt(Address addr, int size);
-
-  bool CanMoveObjectStart(HeapObject* object);
-
-  enum InvocationMode { FROM_GC, FROM_MUTATOR };
-
-  // Maintain marking consistency for IncrementalMarking.
-  void AdjustLiveBytes(Address address, int by, InvocationMode mode);
-
-  // 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 kSweepPreciselyMask = 1;
-  static const int kReduceMemoryFootprintMask = 2;
-  static const int kAbortIncrementalMarkingMask = 4;
-
-  // Making the heap iterable requires us to sweep precisely and abort any
-  // incremental marking as well.
-  static const int kMakeHeapIterableMask =
-      kSweepPreciselyMask | 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_ / 100.0; }
-
-  // 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 hint);
-
-  // 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: ASCII 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 ASCII 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 StartIdleRound() {
-    mark_sweeps_since_idle_round_started_ = 0;
-  }
-
-  void FinishIdleRound() {
-    mark_sweeps_since_idle_round_started_ = kMaxMarkSweepsInIdleRound;
-    scavenges_since_last_idle_round_ = 0;
-  }
-
-  bool EnoughGarbageSinceLastIdleRound() {
-    return (scavenges_since_last_idle_round_ >= kIdleScavengeThreshold);
-  }
-
-  // Estimates how many milliseconds a Mark-Sweep would take to complete.
-  // In idle notification handler we assume that this function will return:
-  // - a number less than 10 for small heaps, which are less than 8Mb.
-  // - a number greater than 10 for large heaps, which are greater than 32Mb.
-  int TimeMarkSweepWouldTakeInMs() {
-    // Rough estimate of how many megabytes of heap can be processed in 1 ms.
-    static const int kMbPerMs = 2;
-
-    int heap_size_mb = static_cast<int>(SizeOfObjects() / MB);
-    return heap_size_mb / kMbPerMs;
-  }
-
-  void AdvanceIdleIncrementalMarking(intptr_t step_size);
-
-  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_;
-
-  int number_idle_notifications_;
-  unsigned int last_idle_notification_gc_count_;
-  bool last_idle_notification_gc_count_init_;
-
-  int mark_sweeps_since_idle_round_started_;
-  unsigned int gc_count_at_last_idle_gc_;
-  int scavenges_since_last_idle_round_;
-
-  // 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 kMaxMarkSweepsInIdleRound = 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_H_