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v8/src/heap.h
mvstanton@chromium.org f3a22f965e The goal is to discover the appropriate heap space for objects created in full 
code. By the time we optimize the code, we'll be able to decide on new or old
space based on the number of surviving objects after one or more gcs.

The mechanism is a "memento" placed behind objects in the heap. It's currently
done for array and object literals, with plans to use mementos for constructed
objects as well (in a later CL).

The feature is behind the flag allocation_site_pretenuring, currently off.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/40063002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18104 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-11-27 14:03:40 +00:00

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// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_HEAP_H_
#define V8_HEAP_H_
#include <cmath>
#include "allocation.h"
#include "assert-scope.h"
#include "globals.h"
#include "incremental-marking.h"
#include "list.h"
#include "mark-compact.h"
#include "objects-visiting.h"
#include "spaces.h"
#include "splay-tree-inl.h"
#include "store-buffer.h"
#include "v8-counters.h"
#include "v8globals.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(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, 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(Object, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \
V(Map, hash_table_map, HashTableMap) \
V(FixedArray, empty_fixed_array, EmptyFixedArray) \
V(ByteArray, empty_byte_array, EmptyByteArray) \
V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
V(Smi, stack_limit, StackLimit) \
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(Object, 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, cons_internalized_string_map, ConsInternalizedStringMap) \
V(Map, cons_ascii_internalized_string_map, ConsAsciiInternalizedStringMap) \
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_byte_array_map, ExternalByteArrayMap) \
V(Map, external_unsigned_byte_array_map, ExternalUnsignedByteArrayMap) \
V(Map, external_short_array_map, ExternalShortArrayMap) \
V(Map, external_unsigned_short_array_map, ExternalUnsignedShortArrayMap) \
V(Map, external_int_array_map, ExternalIntArrayMap) \
V(Map, external_unsigned_int_array_map, ExternalUnsignedIntArrayMap) \
V(Map, external_float_array_map, ExternalFloatArrayMap) \
V(Map, external_double_array_map, ExternalDoubleArrayMap) \
V(Map, external_pixel_array_map, ExternalPixelArrayMap) \
V(ExternalArray, empty_external_byte_array, \
EmptyExternalByteArray) \
V(ExternalArray, empty_external_unsigned_byte_array, \
EmptyExternalUnsignedByteArray) \
V(ExternalArray, empty_external_short_array, EmptyExternalShortArray) \
V(ExternalArray, empty_external_unsigned_short_array, \
EmptyExternalUnsignedShortArray) \
V(ExternalArray, empty_external_int_array, EmptyExternalIntArray) \
V(ExternalArray, empty_external_unsigned_int_array, \
EmptyExternalUnsignedIntArray) \
V(ExternalArray, empty_external_float_array, EmptyExternalFloatArray) \
V(ExternalArray, empty_external_double_array, EmptyExternalDoubleArray) \
V(ExternalArray, empty_external_pixel_array, \
EmptyExternalPixelArray) \
V(Map, non_strict_arguments_elements_map, NonStrictArgumentsElementsMap) \
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, oddball_map, OddballMap) \
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(Smi, last_script_id, LastScriptId) \
V(Script, empty_script, EmptyScript) \
V(Smi, real_stack_limit, RealStackLimit) \
V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \
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) \
V(JSObject, observation_state, ObservationState) \
V(Map, external_map, ExternalMap) \
V(Symbol, frozen_symbol, FrozenSymbol) \
V(Symbol, elements_transition_symbol, ElementsTransitionSymbol) \
V(SeededNumberDictionary, empty_slow_element_dictionary, \
EmptySlowElementDictionary) \
V(Symbol, observed_symbol, ObservedSymbol)
#define ROOT_LIST(V) \
STRONG_ROOT_LIST(V) \
V(StringTable, string_table, StringTable)
#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(dot_iterator_string, ".iterator") \
V(dot_generator_object_string, ".generator_object") \
V(eval_string, "eval") \
V(empty_string, "") \
V(function_string, "function") \
V(length_string, "length") \
V(module_string, "module") \
V(name_string, "name") \
V(native_string, "native") \
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(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(Date_string, "Date") \
V(this_string, "this") \
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(KeyedLoadElementMonomorphic_string, \
"KeyedLoadElementMonomorphic") \
V(KeyedStoreElementMonomorphic_string, \
"KeyedStoreElementMonomorphic") \
V(stack_overflow_string, "kStackOverflowBoilerplate") \
V(illegal_access_string, "illegal access") \
V(illegal_execution_state_string, "illegal execution state") \
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(MakeReferenceError_string, "MakeReferenceError") \
V(MakeSyntaxError_string, "MakeSyntaxError") \
V(MakeTypeError_string, "MakeTypeError") \
V(invalid_lhs_in_assignment_string, "invalid_lhs_in_assignment") \
V(invalid_lhs_in_for_in_string, "invalid_lhs_in_for_in") \
V(invalid_lhs_in_postfix_op_string, "invalid_lhs_in_postfix_op") \
V(invalid_lhs_in_prefix_op_string, "invalid_lhs_in_prefix_op") \
V(illegal_return_string, "illegal_return") \
V(illegal_break_string, "illegal_break") \
V(illegal_continue_string, "illegal_continue") \
V(unknown_label_string, "unknown_label") \
V(redeclaration_string, "redeclaration") \
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(use_strict_string, "use strict") \
V(dot_string, ".") \
V(anonymous_function_string, "(anonymous function)") \
V(compare_ic_string, "==") \
V(strict_compare_ic_string, "===") \
V(infinity_string, "Infinity") \
V(minus_infinity_string, "-Infinity") \
V(hidden_stack_trace_string, "v8::hidden_stack_trace") \
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")
// Forward declarations.
class GCTracer;
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() {
ASSERT(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;
}
ASSERT(GetHeadPage() == Page::FromAllocationTop(limit));
limit_ = reinterpret_cast<intptr_t*>(limit);
if (limit_ <= rear_) {
return;
}
RelocateQueueHead();
}
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) {
ASSERT(!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_));
ASSERT(!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:
ExternalStringTable() { }
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 before setup. Return false if the heap has been
// set up already.
bool ConfigureHeap(int max_semispace_size,
intptr_t max_old_gen_size,
intptr_t max_executable_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_semispace_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_; }
int MaxRegularSpaceAllocationSize() { return InitialSemiSpaceSize() * 4/5; }
// 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_);
}
bool linear_allocation() {
return linear_allocation_scope_depth_ != 0;
}
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();
}
// Allocates and initializes a new JavaScript object based on a
// constructor.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateJSObject(
JSFunction* constructor,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* AllocateJSObjectWithAllocationSite(
JSFunction* constructor,
Handle<AllocationSite> allocation_site);
MUST_USE_RESULT MaybeObject* AllocateJSModule(Context* context,
ScopeInfo* scope_info);
// Allocate a JSArray with no elements
MUST_USE_RESULT MaybeObject* AllocateEmptyJSArray(
ElementsKind elements_kind,
PretenureFlag pretenure = NOT_TENURED) {
return AllocateJSArrayAndStorage(elements_kind, 0, 0,
DONT_INITIALIZE_ARRAY_ELEMENTS,
pretenure);
}
// Allocate a JSArray with a specified length but elements that are left
// uninitialized.
MUST_USE_RESULT MaybeObject* AllocateJSArrayAndStorage(
ElementsKind elements_kind,
int length,
int capacity,
ArrayStorageAllocationMode mode = DONT_INITIALIZE_ARRAY_ELEMENTS,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* AllocateJSArrayStorage(
JSArray* array,
int length,
int capacity,
ArrayStorageAllocationMode mode = DONT_INITIALIZE_ARRAY_ELEMENTS);
// Allocate a JSArray with no elements
MUST_USE_RESULT MaybeObject* AllocateJSArrayWithElements(
FixedArrayBase* array_base,
ElementsKind elements_kind,
int length,
PretenureFlag pretenure = NOT_TENURED);
// Returns a deep copy of the JavaScript object.
// Properties and elements are copied too.
// Returns failure if allocation failed.
// Optionally takes an AllocationSite to be appended in an AllocationMemento.
MUST_USE_RESULT MaybeObject* CopyJSObject(JSObject* source,
AllocationSite* site = NULL);
// Allocates a JS ArrayBuffer object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateJSArrayBuffer();
// Allocates a Harmony proxy or function proxy.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateJSProxy(Object* handler,
Object* prototype);
MUST_USE_RESULT MaybeObject* AllocateJSFunctionProxy(Object* handler,
Object* call_trap,
Object* construct_trap,
Object* prototype);
// Reinitialize a JSReceiver into an (empty) JS object of respective type and
// size, but keeping the original prototype. The receiver must have at least
// the size of the new object. The object is reinitialized and behaves as an
// object that has been freshly allocated.
// Returns failure if an error occured, otherwise object.
MUST_USE_RESULT MaybeObject* ReinitializeJSReceiver(JSReceiver* object,
InstanceType type,
int size);
// Reinitialize an JSGlobalProxy based on a constructor. The object
// must have the same size as objects allocated using the
// constructor. The object is reinitialized and behaves as an
// object that has been freshly allocated using the constructor.
MUST_USE_RESULT MaybeObject* ReinitializeJSGlobalProxy(
JSFunction* constructor, JSGlobalProxy* global);
// Allocates and initializes a new JavaScript object based on a map.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateJSObjectFromMap(
Map* map, PretenureFlag pretenure = NOT_TENURED, bool alloc_props = true);
MUST_USE_RESULT MaybeObject* AllocateJSObjectFromMapWithAllocationSite(
Map* map, Handle<AllocationSite> allocation_site);
// Allocates a heap object based on the map.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* Allocate(Map* map, AllocationSpace space);
MUST_USE_RESULT MaybeObject* AllocateWithAllocationSite(Map* map,
AllocationSpace space, Handle<AllocationSite> allocation_site);
// Allocates a JS Map in the heap.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateMap(
InstanceType instance_type,
int instance_size,
ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND);
// Allocates a partial map for bootstrapping.
MUST_USE_RESULT MaybeObject* AllocatePartialMap(InstanceType instance_type,
int instance_size);
// Allocates an empty code cache.
MUST_USE_RESULT MaybeObject* AllocateCodeCache();
// Allocates a serialized scope info.
MUST_USE_RESULT MaybeObject* AllocateScopeInfo(int length);
// Allocates an External object for v8's external API.
MUST_USE_RESULT MaybeObject* AllocateExternal(void* value);
// Allocates an empty PolymorphicCodeCache.
MUST_USE_RESULT MaybeObject* AllocatePolymorphicCodeCache();
// Allocates a pre-tenured empty AccessorPair.
MUST_USE_RESULT MaybeObject* AllocateAccessorPair();
// Allocates an empty TypeFeedbackInfo.
MUST_USE_RESULT MaybeObject* AllocateTypeFeedbackInfo();
// Allocates an AliasedArgumentsEntry.
MUST_USE_RESULT MaybeObject* AllocateAliasedArgumentsEntry(int slot);
// 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();
// Allocates and fully initializes a String. There are two String
// encodings: ASCII and two byte. One should choose between the three string
// allocation functions based on the encoding of the string buffer used to
// initialized the string.
// - ...FromAscii initializes the string from a buffer that is ASCII
// encoded (it does not check that the buffer is ASCII encoded) and the
// result will be ASCII encoded.
// - ...FromUTF8 initializes the string from a buffer that is UTF-8
// encoded. If the characters are all single-byte characters, the
// result will be ASCII encoded, otherwise it will converted to two
// byte.
// - ...FromTwoByte initializes the string from a buffer that is two-byte
// encoded. If the characters are all single-byte characters, the
// result will be converted to ASCII, otherwise it will be left as
// two-byte.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateStringFromOneByte(
Vector<const uint8_t> str,
PretenureFlag pretenure = NOT_TENURED);
// TODO(dcarney): remove this function.
MUST_USE_RESULT inline MaybeObject* AllocateStringFromOneByte(
Vector<const char> str,
PretenureFlag pretenure = NOT_TENURED) {
return AllocateStringFromOneByte(Vector<const uint8_t>::cast(str),
pretenure);
}
MUST_USE_RESULT inline MaybeObject* AllocateStringFromUtf8(
Vector<const char> str,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* AllocateStringFromUtf8Slow(
Vector<const char> str,
int non_ascii_start,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* AllocateStringFromTwoByte(
Vector<const uc16> str,
PretenureFlag pretenure = NOT_TENURED);
// Allocates an internalized string in old space based on the character
// stream. Returns Failure::RetryAfterGC(requested_bytes, space) if the
// allocation failed.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT inline MaybeObject* AllocateInternalizedStringFromUtf8(
Vector<const char> str,
int chars,
uint32_t hash_field);
MUST_USE_RESULT inline MaybeObject* AllocateOneByteInternalizedString(
Vector<const uint8_t> str,
uint32_t hash_field);
MUST_USE_RESULT inline MaybeObject* AllocateTwoByteInternalizedString(
Vector<const uc16> str,
uint32_t hash_field);
template<typename T>
static inline bool IsOneByte(T t, int chars);
template<typename T>
MUST_USE_RESULT inline MaybeObject* AllocateInternalizedStringImpl(
T t, int chars, uint32_t hash_field);
template<bool is_one_byte, typename T>
MUST_USE_RESULT MaybeObject* AllocateInternalizedStringImpl(
T t, int chars, uint32_t hash_field);
// Allocates 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.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateRawOneByteString(
int length,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* AllocateRawTwoByteString(
int length,
PretenureFlag pretenure = NOT_TENURED);
// Computes a single character string where the character has code.
// A cache is used for ASCII codes.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed. Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* LookupSingleCharacterStringFromCode(
uint16_t code);
// Allocate a byte array of the specified length
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateByteArray(
int length,
PretenureFlag pretenure = NOT_TENURED);
// Allocates an external array of the specified length and type.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateExternalArray(
int length,
ExternalArrayType array_type,
void* external_pointer,
PretenureFlag pretenure);
// Allocate a symbol in old space.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateSymbol();
MUST_USE_RESULT MaybeObject* AllocatePrivateSymbol();
// Allocate a tenured AllocationSite. It's payload is null
MUST_USE_RESULT MaybeObject* AllocateAllocationSite();
// Allocates a fixed array initialized with undefined values
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateFixedArray(
int length,
PretenureFlag pretenure = NOT_TENURED);
// Allocates an uninitialized fixed array. It must be filled by the caller.
//
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateUninitializedFixedArray(int length);
// 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);
// Make a copy of src and return it. Returns
// Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
MUST_USE_RESULT inline MaybeObject* 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 MaybeObject* 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 MaybeObject* CopyFixedDoubleArray(
FixedDoubleArray* 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 MaybeObject* CopyFixedDoubleArrayWithMap(
FixedDoubleArray* 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 MaybeObject* CopyConstantPoolArray(
ConstantPoolArray* 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 MaybeObject* CopyConstantPoolArrayWithMap(
ConstantPoolArray* src, Map* map);
// Allocates a fixed array initialized with the hole values.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateFixedArrayWithHoles(
int length,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* AllocateConstantPoolArray(
int first_int64_index,
int first_ptr_index,
int first_int32_index);
// Allocates a fixed double array with uninitialized values. Returns
// Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateUninitializedFixedDoubleArray(
int length,
PretenureFlag pretenure = NOT_TENURED);
// Allocates a fixed double array with hole values. Returns
// Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateFixedDoubleArrayWithHoles(
int length,
PretenureFlag pretenure = NOT_TENURED);
// AllocateHashTable is identical to AllocateFixedArray except
// that the resulting object has hash_table_map as map.
MUST_USE_RESULT MaybeObject* AllocateHashTable(
int length, PretenureFlag pretenure = NOT_TENURED);
// Allocate a native (but otherwise uninitialized) context.
MUST_USE_RESULT MaybeObject* AllocateNativeContext();
// Allocate a global context.
MUST_USE_RESULT MaybeObject* AllocateGlobalContext(JSFunction* function,
ScopeInfo* scope_info);
// Allocate a module context.
MUST_USE_RESULT MaybeObject* AllocateModuleContext(ScopeInfo* scope_info);
// Allocate a function context.
MUST_USE_RESULT MaybeObject* AllocateFunctionContext(int length,
JSFunction* function);
// Allocate a catch context.
MUST_USE_RESULT MaybeObject* AllocateCatchContext(JSFunction* function,
Context* previous,
String* name,
Object* thrown_object);
// Allocate a 'with' context.
MUST_USE_RESULT MaybeObject* AllocateWithContext(JSFunction* function,
Context* previous,
JSReceiver* extension);
// Allocate a block context.
MUST_USE_RESULT MaybeObject* AllocateBlockContext(JSFunction* function,
Context* previous,
ScopeInfo* info);
// Allocates a new utility object in the old generation.
MUST_USE_RESULT MaybeObject* AllocateStruct(InstanceType type);
// Allocates a function initialized with a shared part.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateFunction(
Map* function_map,
SharedFunctionInfo* shared,
Object* prototype,
PretenureFlag pretenure = TENURED);
// Arguments object size.
static const int kArgumentsObjectSize =
JSObject::kHeaderSize + 2 * kPointerSize;
// Strict mode arguments has no callee so it is smaller.
static const int kArgumentsObjectSizeStrict =
JSObject::kHeaderSize + 1 * kPointerSize;
// Indicies for direct access into argument objects.
static const int kArgumentsLengthIndex = 0;
// callee is only valid in non-strict mode.
static const int kArgumentsCalleeIndex = 1;
// Allocates an arguments object - optionally with an elements array.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateArgumentsObject(
Object* callee, int length);
// Same as NewNumberFromDouble, but may return a preallocated/immutable
// number object (e.g., minus_zero_value_, nan_value_)
MUST_USE_RESULT MaybeObject* NumberFromDouble(
double value, PretenureFlag pretenure = NOT_TENURED);
// Allocated a HeapNumber from value.
MUST_USE_RESULT MaybeObject* AllocateHeapNumber(
double value, PretenureFlag pretenure = NOT_TENURED);
// Converts an int into either a Smi or a HeapNumber object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT inline MaybeObject* NumberFromInt32(
int32_t value, PretenureFlag pretenure = NOT_TENURED);
// Converts an int into either a Smi or a HeapNumber object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT inline MaybeObject* NumberFromUint32(
uint32_t value, PretenureFlag pretenure = NOT_TENURED);
// Allocates a new foreign object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateForeign(
Address address, PretenureFlag pretenure = NOT_TENURED);
// Allocates a new SharedFunctionInfo object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateSharedFunctionInfo(Object* name);
// Allocates a new JSMessageObject object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note that this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateJSMessageObject(
String* type,
JSArray* arguments,
int start_position,
int end_position,
Object* script,
Object* stack_trace,
Object* stack_frames);
// Allocates a new cons string object.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateConsString(String* first,
String* second);
// Allocates a new sub string object which is a substring of an underlying
// string buffer stretching from the index start (inclusive) to the index
// end (exclusive).
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateSubString(
String* buffer,
int start,
int end,
PretenureFlag pretenure = NOT_TENURED);
// Allocate a new external string object, which is backed by a string
// resource that resides outside the V8 heap.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* AllocateExternalStringFromAscii(
const ExternalAsciiString::Resource* resource);
MUST_USE_RESULT MaybeObject* AllocateExternalStringFromTwoByte(
const ExternalTwoByteString::Resource* resource);
// Finalizes an external string by deleting the associated external
// data and clearing the resource pointer.
inline void FinalizeExternalString(String* string);
// Allocates an uninitialized object. The memory is non-executable if the
// hardware and OS allow.
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT inline MaybeObject* AllocateRaw(int size_in_bytes,
AllocationSpace space,
AllocationSpace retry_space);
// Initialize a filler object to keep the ability to iterate over the heap
// when shortening objects.
void CreateFillerObjectAt(Address addr, int size);
// Makes a new native code object
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed. On success, the pointer to the Code object is stored in the
// self_reference. This allows generated code to reference its own Code
// object by containing this pointer.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* CreateCode(
const CodeDesc& desc,
Code::Flags flags,
Handle<Object> self_reference,
bool immovable = false,
bool crankshafted = false,
int prologue_offset = Code::kPrologueOffsetNotSet);
MUST_USE_RESULT MaybeObject* CopyCode(Code* code);
// Copy the code and scope info part of the code object, but insert
// the provided data as the relocation information.
MUST_USE_RESULT MaybeObject* CopyCode(Code* code, Vector<byte> reloc_info);
// Finds the internalized copy for string in the string table.
// If not found, a new string is added to the table and returned.
// Returns Failure::RetryAfterGC(requested_bytes, space) if allocation
// failed.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* InternalizeUtf8String(Vector<const char> str);
MUST_USE_RESULT MaybeObject* InternalizeUtf8String(const char* str) {
return InternalizeUtf8String(CStrVector(str));
}
MUST_USE_RESULT MaybeObject* InternalizeOneByteString(
Vector<const uint8_t> str);
MUST_USE_RESULT MaybeObject* InternalizeTwoByteString(Vector<const uc16> str);
MUST_USE_RESULT MaybeObject* InternalizeString(String* str);
MUST_USE_RESULT MaybeObject* InternalizeOneByteString(
Handle<SeqOneByteString> string, int from, int length);
bool InternalizeStringIfExists(String* str, String** result);
bool InternalizeTwoCharsStringIfExists(String* str, String** result);
// Compute the matching internalized string map for a string if possible.
// NULL is returned if string is in new space or not flattened.
Map* InternalizedStringMapForString(String* str);
// Tries to flatten a string before compare operation.
//
// Returns a failure in case it was decided that flattening was
// necessary and failed. Note, if flattening is not necessary the
// string might stay non-flat even when not a failure is returned.
//
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT inline MaybeObject* PrepareForCompare(String* str);
// 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);
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);
// 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();
// Ensure that we have swept all spaces in such a way that we can iterate
// over all objects. May cause a GC.
void EnsureHeapIsIterable();
// Notify the heap that a context has been disposed.
int NotifyContextDisposed();
// Utility to invoke the scavenger. This is needed in test code to
// ensure correct callback for weak global handles.
void PerformScavenge();
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_; }
#ifdef DEBUG
// Utility used with flag gc-greedy.
void GarbageCollectionGreedyCheck();
#endif
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() { return native_contexts_list_; }
void set_array_buffers_list(Object* object) {
array_buffers_list_ = object;
}
Object* array_buffers_list() { return array_buffers_list_; }
void set_allocation_sites_list(Object* object) {
allocation_sites_list_ = object;
}
Object* allocation_sites_list() { return allocation_sites_list_; }
Object** allocation_sites_list_address() { return &allocation_sites_list_; }
Object* weak_object_to_code_table() { return weak_object_to_code_table_; }
// 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 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);
}
// 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]);
}
// Get address of native contexts list for serialization support.
Object** native_contexts_list_address() {
return &native_contexts_list_;
}
#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
}
// Print short heap statistics.
void PrintShortHeapStatistics();
// Makes a new internalized string object
// Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
// failed.
// Please note this function does not perform a garbage collection.
MUST_USE_RESULT MaybeObject* CreateInternalizedString(
const char* str, int length, int hash);
MUST_USE_RESULT MaybeObject* CreateInternalizedString(String* str);
// 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;
}
bool disallow_allocation_failure() {
return disallow_allocation_failure_;
}
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);
// 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);
// 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.
//
bool CreateApiObjects();
// Attempt to find the number in a small cache. If we finds it, return
// the string representation of the number. Otherwise return undefined.
Object* GetNumberStringCache(Object* number);
// Update the cache with a new number-string pair.
void SetNumberStringCache(Object* number, String* str);
// Adjusts the amount of registered external memory.
// Returns the adjusted value.
inline int64_t AdjustAmountOfExternalAllocatedMemory(
int64_t change_in_bytes);
// This is only needed for testing high promotion mode.
void SetNewSpaceHighPromotionModeActive(bool mode) {
new_space_high_promotion_mode_active_ = mode;
}
// Returns the allocation mode (pre-tenuring) based on observed promotion
// rates of previous collections.
inline PretenureFlag GetPretenureMode() {
return FLAG_pretenuring && new_space_high_promotion_mode_active_
? TENURED : NOT_TENURED;
}
inline Address* NewSpaceHighPromotionModeActiveAddress() {
return reinterpret_cast<Address*>(&new_space_high_promotion_mode_active_);
}
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);
intptr_t OldGenerationAllocationLimit(intptr_t old_gen_size) {
const int divisor = FLAG_stress_compaction ? 10 :
new_space_high_promotion_mode_active_ ? 1 : 3;
intptr_t limit =
Max(old_gen_size + old_gen_size / divisor,
kMinimumOldGenerationAllocationLimit);
limit += new_space_.Capacity();
// TODO(hpayer): Can be removed when when pretenuring is supported for all
// allocation sites.
if (IsHighSurvivalRate() && IsStableOrIncreasingSurvivalTrend()) {
limit *= 2;
}
intptr_t halfway_to_the_max = (old_gen_size + max_old_generation_size_) / 2;
return Min(limit, halfway_to_the_max);
}
// 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.
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,
kStrongRootListLength = kStringTableRootIndex,
kRootListLength
};
STATIC_CHECK(kUndefinedValueRootIndex == Internals::kUndefinedValueRootIndex);
STATIC_CHECK(kNullValueRootIndex == Internals::kNullValueRootIndex);
STATIC_CHECK(kTrueValueRootIndex == Internals::kTrueValueRootIndex);
STATIC_CHECK(kFalseValueRootIndex == Internals::kFalseValueRootIndex);
STATIC_CHECK(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);
MUST_USE_RESULT MaybeObject* NumberToString(
Object* number, bool check_number_string_cache = true,
PretenureFlag pretenure = NOT_TENURED);
MUST_USE_RESULT MaybeObject* Uint32ToString(
uint32_t value, bool check_number_string_cache = true);
Map* MapForExternalArrayType(ExternalArrayType array_type);
RootListIndex RootIndexForExternalArrayType(
ExternalArrayType array_type);
RootListIndex RootIndexForEmptyExternalArray(ElementsKind kind);
ExternalArray* EmptyExternalArrayForMap(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 IncrementYoungSurvivorsCounter(int survived) {
ASSERT(survived >= 0);
young_survivors_after_last_gc_ = survived;
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);
// Helper function that governs the promotion policy from new space to
// old. If the object's old address lies below the new space's age
// mark or if we've already filled the bottom 1/16th of the to space,
// we try to promote this object.
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;
}
}
// 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_; }
// TODO(hpayer): remove, should be handled by GCTracer
void AddMarkingTime(double marking_time) {
marking_time_ += marking_time;
}
double marking_time() const {
return marking_time_;
}
// TODO(hpayer): remove, should be handled by GCTracer
void AddSweepingTime(double sweeping_time) {
sweeping_time_ += sweeping_time;
}
double sweeping_time() const {
return sweeping_time_;
}
MarkCompactCollector* mark_compact_collector() {
return &mark_compact_collector_;
}
StoreBuffer* store_buffer() {
return &store_buffer_;
}
Marking* marking() {
return &marking_;
}
IncrementalMarking* incremental_marking() {
return &incremental_marking_;
}
bool IsSweepingComplete() {
return !mark_compact_collector()->IsConcurrentSweepingInProgress() &&
old_data_space()->IsLazySweepingComplete() &&
old_pointer_space()->IsLazySweepingComplete();
}
bool AdvanceSweepers(int step_size);
bool EnsureSweepersProgressed(int step_size) {
bool sweeping_complete = old_data_space()->EnsureSweeperProgress(step_size);
sweeping_complete &= old_pointer_space()->EnsureSweeperProgress(step_size);
return sweeping_complete;
}
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);
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());
ASSERT(FLAG_randomize_hashes || seed == 0);
return seed;
}
void SetArgumentsAdaptorDeoptPCOffset(int pc_offset) {
ASSERT(arguments_adaptor_deopt_pc_offset() == Smi::FromInt(0));
set_arguments_adaptor_deopt_pc_offset(Smi::FromInt(pc_offset));
}
void SetConstructStubDeoptPCOffset(int pc_offset) {
ASSERT(construct_stub_deopt_pc_offset() == Smi::FromInt(0));
set_construct_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
}
void SetGetterStubDeoptPCOffset(int pc_offset) {
ASSERT(getter_stub_deopt_pc_offset() == Smi::FromInt(0));
set_getter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
}
void SetSetterStubDeoptPCOffset(int pc_offset) {
ASSERT(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_;
}
// 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) {
ASSERT(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;
ASSERT(code_sub_type_index >= FIRST_CODE_KIND_SUB_TYPE &&
code_sub_type_index < FIRST_CODE_AGE_SUB_TYPE);
ASSERT(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) {
ASSERT(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) {
if (FLAG_concurrent_recompilation) {
heap_->relocation_mutex_->Lock();
}
}
~RelocationLock() {
if (FLAG_concurrent_recompilation) {
heap_->relocation_mutex_->Unlock();
}
}
private:
Heap* heap_;
};
MaybeObject* AddWeakObjectToCodeDependency(Object* obj, DependentCode* dep);
DependentCode* LookupWeakObjectToCodeDependency(Object* obj);
void InitializeWeakObjectToCodeTable() {
set_weak_object_to_code_table(undefined_value());
}
void EnsureWeakObjectToCodeTable();
private:
Heap();
// 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];
intptr_t code_range_size_;
int reserved_semispace_size_;
int max_semispace_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_;
int linear_allocation_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_;
// Returns the amount of external memory registered since last global gc.
int64_t PromotedExternalMemorySize();
unsigned int ms_count_; // how many mark-sweep collections happened
unsigned int gc_count_; // how many gc happened
// 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. */ \
ASSERT(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_;
// Do we expect to be able to handle allocation failure at this
// time?
bool disallow_allocation_failure_;
#endif // DEBUG
// Indicates that the new space should be kept small due to high promotion
// rates caused by the mutator allocating a lot of long-lived objects.
// TODO(hpayer): change to bool if no longer accessed from generated code
intptr_t new_space_high_promotion_mode_active_;
// 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_;
// Used to adjust the limits that control the timing of the next GC.
intptr_t size_of_old_gen_at_last_old_space_gc_;
// Limit on the amount of externally allocated memory allowed
// between global GCs. If reached a global GC is forced.
intptr_t external_allocation_limit_;
// 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_;
// 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_;
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) {
ASSERT(!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();
// Checks whether a global GC is necessary
GarbageCollector SelectGarbageCollector(AllocationSpace space,
const char** reason);
// Performs garbage collection operation.
// Returns whether there is a chance that another major GC could
// collect more garbage.
bool CollectGarbage(AllocationSpace space,
GarbageCollector collector,
const char* gc_reason,
const char* collector_reason);
// Performs garbage collection
// Returns whether there is a chance another major GC could
// collect more garbage.
bool PerformGarbageCollection(GarbageCollector collector,
GCTracer* tracer);
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) {
ASSERT(preferred_old_space == OLD_POINTER_SPACE ||
preferred_old_space == OLD_DATA_SPACE);
if (object_size > Page::kMaxNonCodeHeapObjectSize) return LO_SPACE;
return (pretenure == TENURED) ? preferred_old_space : NEW_SPACE;
}
// Allocate an uninitialized fixed array.
MUST_USE_RESULT MaybeObject* AllocateRawFixedArray(
int length, PretenureFlag pretenure);
// Allocate an uninitialized fixed double array.
MUST_USE_RESULT MaybeObject* AllocateRawFixedDoubleArray(
int length, PretenureFlag pretenure);
// Allocate an initialized fixed array with the given filler value.
MUST_USE_RESULT MaybeObject* AllocateFixedArrayWithFiller(
int length, PretenureFlag pretenure, Object* filler);
// Initializes a JSObject based on its map.
void InitializeJSObjectFromMap(JSObject* obj,
FixedArray* properties,
Map* map);
void InitializeAllocationMemento(AllocationMemento* memento,
AllocationSite* allocation_site);
bool CreateInitialMaps();
bool CreateInitialObjects();
// 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();
void CreateStubsRequiringBuiltins();
MUST_USE_RESULT MaybeObject* CreateOddball(const char* to_string,
Object* to_number,
byte kind);
// Allocate a JSArray with no elements
MUST_USE_RESULT MaybeObject* AllocateJSArray(
ElementsKind elements_kind,
PretenureFlag pretenure = NOT_TENURED);
// Allocate empty fixed array.
MUST_USE_RESULT MaybeObject* AllocateEmptyFixedArray();
// Allocate empty external array of given type.
MUST_USE_RESULT MaybeObject* AllocateEmptyExternalArray(
ExternalArrayType array_type);
// Allocate empty fixed double array.
MUST_USE_RESULT MaybeObject* AllocateEmptyFixedDoubleArray();
// Allocate a tenured simple cell.
MUST_USE_RESULT MaybeObject* AllocateCell(Object* value);
// Allocate a tenured JS global property cell initialized with the hole.
MUST_USE_RESULT MaybeObject* AllocatePropertyCell();
// Allocate Box.
MUST_USE_RESULT MaybeObject* AllocateBox(Object* value,
PretenureFlag pretenure);
// 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(GCTracer* tracer);
// Code to be run before and after mark-compact.
void MarkCompactPrologue();
void ProcessNativeContexts(WeakObjectRetainer* retainer, bool record_slots);
void ProcessArrayBuffers(WeakObjectRetainer* retainer, bool record_slots);
void ProcessAllocationSites(WeakObjectRetainer* retainer, bool record_slots);
// 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);
// Initializes a function with a shared part and prototype.
// Note: this code was factored out of AllocateFunction such that
// other parts of the VM could use it. Specifically, a function that creates
// instances of type JS_FUNCTION_TYPE benefit from the use of this function.
// Please note this does not perform a garbage collection.
inline void InitializeFunction(
JSFunction* function,
SharedFunctionInfo* shared,
Object* prototype);
// Total RegExp code ever generated
double total_regexp_code_generated_;
GCTracer* tracer_;
// Allocates a small number to string cache.
MUST_USE_RESULT MaybeObject* AllocateInitialNumberStringCache();
// Creates and installs the full-sized number string cache.
void AllocateFullSizeNumberStringCache();
// Get the length of the number to string cache based on the max semispace
// size.
int FullSizeNumberStringCacheLength();
// Flush the number to string cache.
void FlushNumberStringCache();
void UpdateSurvivalRateTrend(int start_new_space_size);
enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
static const int kYoungSurvivalRateHighThreshold = 90;
static const int kYoungSurvivalRateLowThreshold = 10;
static const int kYoungSurvivalRateAllowedDeviation = 15;
int young_survivors_after_last_gc_;
int high_survival_rate_period_length_;
int low_survival_rate_period_length_;
double survival_rate_;
SurvivalRateTrend previous_survival_rate_trend_;
SurvivalRateTrend survival_rate_trend_;
void set_survival_rate_trend(SurvivalRateTrend survival_rate_trend) {
ASSERT(survival_rate_trend != FLUCTUATING);
previous_survival_rate_trend_ = survival_rate_trend_;
survival_rate_trend_ = survival_rate_trend;
}
SurvivalRateTrend survival_rate_trend() {
if (survival_rate_trend_ == STABLE) {
return STABLE;
} else if (previous_survival_rate_trend_ == STABLE) {
return survival_rate_trend_;
} else if (survival_rate_trend_ != previous_survival_rate_trend_) {
return FLUCTUATING;
} else {
return survival_rate_trend_;
}
}
bool IsStableOrIncreasingSurvivalTrend() {
switch (survival_rate_trend()) {
case STABLE:
case INCREASING:
return true;
default:
return false;
}
}
bool IsStableOrDecreasingSurvivalTrend() {
switch (survival_rate_trend()) {
case STABLE:
case DECREASING:
return true;
default:
return false;
}
}
bool IsIncreasingSurvivalTrend() {
return survival_rate_trend() == INCREASING;
}
bool IsHighSurvivalRate() {
return high_survival_rate_period_length_ > 0;
}
bool IsLowSurvivalRate() {
return low_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;
}
// Returns true if no more GC work is left.
bool IdleGlobalGC();
void AdvanceIdleIncrementalMarking(intptr_t step_size);
void ClearObjectStats(bool clear_last_time_stats = false);
void set_weak_object_to_code_table(Object* value) {
ASSERT(!InNewSpace(value));
weak_object_to_code_table_ = value;
}
Object** weak_object_to_code_table_address() {
return &weak_object_to_code_table_;
}
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_;
// Size of objects alive after last GC.
intptr_t alive_after_last_gc_;
double last_gc_end_timestamp_;
// 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 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_;
Mutex* relocation_mutex_;
#ifdef DEBUG
bool relocation_mutex_locked_by_optimizer_thread_;
#endif // DEBUG;
friend class Factory;
friend class GCTracer;
friend class DisallowAllocationFailure;
friend class AlwaysAllocateScope;
friend class Page;
friend class Isolate;
friend class MarkCompactCollector;
friend class MarkCompactMarkingVisitor;
friend class MapCompact;
#ifdef VERIFY_HEAP
friend class NoWeakObjectVerificationScope;
#endif
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 DisallowAllocationFailure {
public:
inline DisallowAllocationFailure();
inline ~DisallowAllocationFailure();
#ifdef DEBUG
private:
bool old_state_;
#endif
};
class AlwaysAllocateScope {
public:
inline AlwaysAllocateScope();
inline ~AlwaysAllocateScope();
private:
// Implicitly disable artificial allocation failures.
DisallowAllocationFailure disallow_allocation_failure_;
};
#ifdef VERIFY_HEAP
class NoWeakObjectVerificationScope {
public:
inline NoWeakObjectVerificationScope();
inline ~NoWeakObjectVerificationScope();
};
#endif
// 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);
};
// 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 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:
// Perform the initialization.
void Init();
// Perform all necessary shutdown (destruction) work.
void Shutdown();
HeapObject* NextObject();
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(Map* map, Name* name);
// Update an element in the cache.
void Update(Map* map, 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 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(Map* map, 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) {
ASSERT(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);
};
// GCTracer collects and prints ONE line after each garbage collector
// invocation IFF --trace_gc is used.
class GCTracer BASE_EMBEDDED {
public:
class Scope BASE_EMBEDDED {
public:
enum ScopeId {
EXTERNAL,
MC_MARK,
MC_SWEEP,
MC_SWEEP_NEWSPACE,
MC_EVACUATE_PAGES,
MC_UPDATE_NEW_TO_NEW_POINTERS,
MC_UPDATE_ROOT_TO_NEW_POINTERS,
MC_UPDATE_OLD_TO_NEW_POINTERS,
MC_UPDATE_POINTERS_TO_EVACUATED,
MC_UPDATE_POINTERS_BETWEEN_EVACUATED,
MC_UPDATE_MISC_POINTERS,
MC_WEAKCOLLECTION_PROCESS,
MC_WEAKCOLLECTION_CLEAR,
MC_FLUSH_CODE,
kNumberOfScopes
};
Scope(GCTracer* tracer, ScopeId scope)
: tracer_(tracer),
scope_(scope) {
start_time_ = OS::TimeCurrentMillis();
}
~Scope() {
ASSERT(scope_ < kNumberOfScopes); // scope_ is unsigned.
tracer_->scopes_[scope_] += OS::TimeCurrentMillis() - start_time_;
}
private:
GCTracer* tracer_;
ScopeId scope_;
double start_time_;
};
explicit GCTracer(Heap* heap,
const char* gc_reason,
const char* collector_reason);
~GCTracer();
// Sets the collector.
void set_collector(GarbageCollector collector) { collector_ = collector; }
// Sets the GC count.
void set_gc_count(unsigned int count) { gc_count_ = count; }
// Sets the full GC count.
void set_full_gc_count(int count) { full_gc_count_ = count; }
void increment_promoted_objects_size(int object_size) {
promoted_objects_size_ += object_size;
}
void increment_nodes_died_in_new_space() {
nodes_died_in_new_space_++;
}
void increment_nodes_copied_in_new_space() {
nodes_copied_in_new_space_++;
}
void increment_nodes_promoted() {
nodes_promoted_++;
}
private:
// Returns a string matching the collector.
const char* CollectorString();
// Returns size of object in heap (in MB).
inline double SizeOfHeapObjects();
// Timestamp set in the constructor.
double start_time_;
// Size of objects in heap set in constructor.
intptr_t start_object_size_;
// Size of memory allocated from OS set in constructor.
intptr_t start_memory_size_;
// Type of collector.
GarbageCollector collector_;
// A count (including this one, e.g. the first collection is 1) of the
// number of garbage collections.
unsigned int gc_count_;
// A count (including this one) of the number of full garbage collections.
int full_gc_count_;
// Amounts of time spent in different scopes during GC.
double scopes_[Scope::kNumberOfScopes];
// Total amount of space either wasted or contained in one of free lists
// before the current GC.
intptr_t in_free_list_or_wasted_before_gc_;
// Difference between space used in the heap at the beginning of the current
// collection and the end of the previous collection.
intptr_t allocated_since_last_gc_;
// Amount of time spent in mutator that is time elapsed between end of the
// previous collection and the beginning of the current one.
double spent_in_mutator_;
// Size of objects promoted during the current collection.
intptr_t promoted_objects_size_;
// Number of died nodes in the new space.
int nodes_died_in_new_space_;
// Number of copied nodes to the new space.
int nodes_copied_in_new_space_;
// Number of promoted nodes to the old space.
int nodes_promoted_;
// Incremental marking steps counters.
int steps_count_;
double steps_took_;
double longest_step_;
int steps_count_since_last_gc_;
double steps_took_since_last_gc_;
Heap* heap_;
const char* gc_reason_;
const char* collector_reason_;
};
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(Heap* heap,
String* key_string,
Object* key_pattern,
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;
};
class TranscendentalCache {
public:
enum Type {ACOS, ASIN, ATAN, COS, EXP, LOG, SIN, TAN, kNumberOfCaches};
static const int kTranscendentalTypeBits = 3;
STATIC_ASSERT((1 << kTranscendentalTypeBits) >= kNumberOfCaches);
// Returns a heap number with f(input), where f is a math function specified
// by the 'type' argument.
MUST_USE_RESULT inline MaybeObject* Get(Type type, double input);
// The cache contains raw Object pointers. This method disposes of
// them before a garbage collection.
void Clear();
private:
class SubCache {
static const int kCacheSize = 512;
explicit SubCache(Isolate* isolate, Type t);
MUST_USE_RESULT inline MaybeObject* Get(double input);
inline double Calculate(double input);
struct Element {
uint32_t in[2];
Object* output;
};
union Converter {
double dbl;
uint32_t integers[2];
};
inline static int Hash(const Converter& c) {
uint32_t hash = (c.integers[0] ^ c.integers[1]);
hash ^= static_cast<int32_t>(hash) >> 16;
hash ^= static_cast<int32_t>(hash) >> 8;
return (hash & (kCacheSize - 1));
}
Element elements_[kCacheSize];
Type type_;
Isolate* isolate_;
// Allow access to the caches_ array as an ExternalReference.
friend class ExternalReference;
// Inline implementation of the cache.
friend class TranscendentalCacheStub;
// For evaluating value.
friend class TranscendentalCache;
DISALLOW_COPY_AND_ASSIGN(SubCache);
};
explicit TranscendentalCache(Isolate* isolate) : isolate_(isolate) {
for (int i = 0; i < kNumberOfCaches; ++i) caches_[i] = NULL;
}
~TranscendentalCache() {
for (int i = 0; i < kNumberOfCaches; ++i) delete caches_[i];
}
// Used to create an external reference.
inline Address cache_array_address();
// Instantiation
friend class Isolate;
// Inline implementation of the caching.
friend class TranscendentalCacheStub;
// Allow access to the caches_ array as an ExternalReference.
friend class ExternalReference;
Isolate* isolate_;
SubCache* caches_[kNumberOfCaches];
DISALLOW_COPY_AND_ASSIGN(TranscendentalCache);
};
// 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));
ASSERT(!IsMarked(object));
}
static void SetMark(HeapObject* object) {
uintptr_t map_word = object->map_word().ToRawValue();
object->set_map_word(MapWord::FromRawValue(map_word & ~kNotMarkedBit));
ASSERT(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);
};
#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.
};
// 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();
// Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
static const int kMarkTag = 2;
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_
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