handles.cc revision 0d5e116f6aee03185f237311a943491bb079a768 
1// Copyright 2009 the V8 project authors. All rights reserved.
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3// modification, are permitted provided that the following conditions are
4// met:
5//
6//     * Redistributions of source code must retain the above copyright
7//       notice, this list of conditions and the following disclaimer.
8//     * Redistributions in binary form must reproduce the above
9//       copyright notice, this list of conditions and the following
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11//       with the distribution.
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15//
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20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#include "v8.h"
29
30#include "accessors.h"
31#include "api.h"
32#include "arguments.h"
33#include "bootstrapper.h"
34#include "compiler.h"
35#include "debug.h"
36#include "execution.h"
37#include "global-handles.h"
38#include "natives.h"
39#include "runtime.h"
40#include "stub-cache.h"
41
42namespace v8 {
43namespace internal {
44
45
46v8::ImplementationUtilities::HandleScopeData HandleScope::current_ =
47    { -1, NULL, NULL };
48
49
50int HandleScope::NumberOfHandles() {
51  int n = HandleScopeImplementer::instance()->blocks()->length();
52  if (n == 0) return 0;
53  return ((n - 1) * kHandleBlockSize) + static_cast<int>(
54      (current_.next - HandleScopeImplementer::instance()->blocks()->last()));
55}
56
57
58Object** HandleScope::Extend() {
59  Object** result = current_.next;
60
61  ASSERT(result == current_.limit);
62  // Make sure there's at least one scope on the stack and that the
63  // top of the scope stack isn't a barrier.
64  if (current_.extensions < 0) {
65    Utils::ReportApiFailure("v8::HandleScope::CreateHandle()",
66                            "Cannot create a handle without a HandleScope");
67    return NULL;
68  }
69  HandleScopeImplementer* impl = HandleScopeImplementer::instance();
70  // If there's more room in the last block, we use that. This is used
71  // for fast creation of scopes after scope barriers.
72  if (!impl->blocks()->is_empty()) {
73    Object** limit = &impl->blocks()->last()[kHandleBlockSize];
74    if (current_.limit != limit) {
75      current_.limit = limit;
76    }
77  }
78
79  // If we still haven't found a slot for the handle, we extend the
80  // current handle scope by allocating a new handle block.
81  if (result == current_.limit) {
82    // If there's a spare block, use it for growing the current scope.
83    result = impl->GetSpareOrNewBlock();
84    // Add the extension to the global list of blocks, but count the
85    // extension as part of the current scope.
86    impl->blocks()->Add(result);
87    current_.extensions++;
88    current_.limit = &result[kHandleBlockSize];
89  }
90
91  return result;
92}
93
94
95void HandleScope::DeleteExtensions() {
96  ASSERT(current_.extensions != 0);
97  HandleScopeImplementer::instance()->DeleteExtensions(current_.extensions);
98}
99
100
101void HandleScope::ZapRange(Object** start, Object** end) {
102  if (start == NULL) return;
103  for (Object** p = start; p < end; p++) {
104    *reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
105  }
106}
107
108
109Address HandleScope::current_extensions_address() {
110  return reinterpret_cast<Address>(&current_.extensions);
111}
112
113
114Address HandleScope::current_next_address() {
115  return reinterpret_cast<Address>(&current_.next);
116}
117
118
119Address HandleScope::current_limit_address() {
120  return reinterpret_cast<Address>(&current_.limit);
121}
122
123
124Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray> content,
125                                      Handle<JSArray> array) {
126  CALL_HEAP_FUNCTION(content->AddKeysFromJSArray(*array), FixedArray);
127}
128
129
130Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
131                               Handle<FixedArray> second) {
132  CALL_HEAP_FUNCTION(first->UnionOfKeys(*second), FixedArray);
133}
134
135
136Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
137    Handle<JSFunction> constructor,
138    Handle<JSGlobalProxy> global) {
139  CALL_HEAP_FUNCTION(Heap::ReinitializeJSGlobalProxy(*constructor, *global),
140                     JSGlobalProxy);
141}
142
143
144void SetExpectedNofProperties(Handle<JSFunction> func, int nof) {
145  // If objects constructed from this function exist then changing
146  // 'estimated_nof_properties' is dangerous since the previois value might
147  // have been compiled into the fast construct stub. More over, the inobject
148  // slack tracking logic might have adjusted the previous value, so even
149  // passing the same value is risky.
150  if (func->shared()->live_objects_may_exist()) return;
151
152  func->shared()->set_expected_nof_properties(nof);
153  if (func->has_initial_map()) {
154    Handle<Map> new_initial_map =
155        Factory::CopyMapDropTransitions(Handle<Map>(func->initial_map()));
156    new_initial_map->set_unused_property_fields(nof);
157    func->set_initial_map(*new_initial_map);
158  }
159}
160
161
162void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value) {
163  CALL_HEAP_FUNCTION_VOID(func->SetPrototype(*value));
164}
165
166
167static int ExpectedNofPropertiesFromEstimate(int estimate) {
168  // If no properties are added in the constructor, they are more likely
169  // to be added later.
170  if (estimate == 0) estimate = 2;
171
172  // We do not shrink objects that go into a snapshot (yet), so we adjust
173  // the estimate conservatively.
174  if (Serializer::enabled()) return estimate + 2;
175
176  // Inobject slack tracking will reclaim redundant inobject space later,
177  // so we can afford to adjust the estimate generously.
178  return estimate + 6;
179}
180
181
182void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
183                                          int estimate) {
184  // See the comment in SetExpectedNofProperties.
185  if (shared->live_objects_may_exist()) return;
186
187  shared->set_expected_nof_properties(
188      ExpectedNofPropertiesFromEstimate(estimate));
189}
190
191
192void NormalizeProperties(Handle<JSObject> object,
193                         PropertyNormalizationMode mode,
194                         int expected_additional_properties) {
195  CALL_HEAP_FUNCTION_VOID(object->NormalizeProperties(
196      mode,
197      expected_additional_properties));
198}
199
200
201void NormalizeElements(Handle<JSObject> object) {
202  CALL_HEAP_FUNCTION_VOID(object->NormalizeElements());
203}
204
205
206void TransformToFastProperties(Handle<JSObject> object,
207                               int unused_property_fields) {
208  CALL_HEAP_FUNCTION_VOID(
209      object->TransformToFastProperties(unused_property_fields));
210}
211
212
213void FlattenString(Handle<String> string) {
214  CALL_HEAP_FUNCTION_VOID(string->TryFlatten());
215}
216
217
218Handle<String> FlattenGetString(Handle<String> string) {
219  Handle<String> result;
220  CALL_AND_RETRY(string->TryFlatten(),
221                 { result = Handle<String>(String::cast(__object__));
222                   break; },
223                 return Handle<String>());
224  ASSERT(string->IsFlat());
225  return result;
226}
227
228
229Handle<Object> SetPrototype(Handle<JSFunction> function,
230                            Handle<Object> prototype) {
231  ASSERT(function->should_have_prototype());
232  CALL_HEAP_FUNCTION(Accessors::FunctionSetPrototype(*function,
233                                                     *prototype,
234                                                     NULL),
235                     Object);
236}
237
238
239Handle<Object> SetProperty(Handle<JSObject> object,
240                           Handle<String> key,
241                           Handle<Object> value,
242                           PropertyAttributes attributes) {
243  CALL_HEAP_FUNCTION(object->SetProperty(*key, *value, attributes), Object);
244}
245
246
247Handle<Object> SetProperty(Handle<Object> object,
248                           Handle<Object> key,
249                           Handle<Object> value,
250                           PropertyAttributes attributes) {
251  CALL_HEAP_FUNCTION(
252      Runtime::SetObjectProperty(object, key, value, attributes), Object);
253}
254
255
256Handle<Object> ForceSetProperty(Handle<JSObject> object,
257                                Handle<Object> key,
258                                Handle<Object> value,
259                                PropertyAttributes attributes) {
260  CALL_HEAP_FUNCTION(
261      Runtime::ForceSetObjectProperty(object, key, value, attributes), Object);
262}
263
264
265Handle<Object> SetNormalizedProperty(Handle<JSObject> object,
266                                     Handle<String> key,
267                                     Handle<Object> value,
268                                     PropertyDetails details) {
269  CALL_HEAP_FUNCTION(object->SetNormalizedProperty(*key, *value, details),
270                     Object);
271}
272
273
274Handle<Object> ForceDeleteProperty(Handle<JSObject> object,
275                                   Handle<Object> key) {
276  CALL_HEAP_FUNCTION(Runtime::ForceDeleteObjectProperty(object, key), Object);
277}
278
279
280Handle<Object> IgnoreAttributesAndSetLocalProperty(
281    Handle<JSObject> object,
282    Handle<String> key,
283    Handle<Object> value,
284    PropertyAttributes attributes) {
285  CALL_HEAP_FUNCTION(object->
286      IgnoreAttributesAndSetLocalProperty(*key, *value, attributes), Object);
287}
288
289
290Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object,
291                                          Handle<String> key,
292                                          Handle<Object> value,
293                                          PropertyAttributes attributes) {
294  CALL_HEAP_FUNCTION(object->SetPropertyWithInterceptor(*key,
295                                                        *value,
296                                                        attributes),
297                     Object);
298}
299
300
301Handle<Object> GetProperty(Handle<JSObject> obj,
302                           const char* name) {
303  Handle<String> str = Factory::LookupAsciiSymbol(name);
304  CALL_HEAP_FUNCTION(obj->GetProperty(*str), Object);
305}
306
307
308Handle<Object> GetProperty(Handle<Object> obj,
309                           Handle<Object> key) {
310  CALL_HEAP_FUNCTION(Runtime::GetObjectProperty(obj, key), Object);
311}
312
313
314Handle<Object> GetElement(Handle<Object> obj,
315                          uint32_t index) {
316  CALL_HEAP_FUNCTION(Runtime::GetElement(obj, index), Object);
317}
318
319
320Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
321                                          Handle<JSObject> holder,
322                                          Handle<String> name,
323                                          PropertyAttributes* attributes) {
324  CALL_HEAP_FUNCTION(holder->GetPropertyWithInterceptor(*receiver,
325                                                        *name,
326                                                        attributes),
327                     Object);
328}
329
330
331Handle<Object> GetPrototype(Handle<Object> obj) {
332  Handle<Object> result(obj->GetPrototype());
333  return result;
334}
335
336
337Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value) {
338  const bool skip_hidden_prototypes = false;
339  CALL_HEAP_FUNCTION(obj->SetPrototype(*value, skip_hidden_prototypes), Object);
340}
341
342
343Handle<Object> GetHiddenProperties(Handle<JSObject> obj,
344                                   bool create_if_needed) {
345  Object* holder = obj->BypassGlobalProxy();
346  if (holder->IsUndefined()) return Factory::undefined_value();
347  obj = Handle<JSObject>(JSObject::cast(holder));
348
349  if (obj->HasFastProperties()) {
350    // If the object has fast properties, check whether the first slot
351    // in the descriptor array matches the hidden symbol. Since the
352    // hidden symbols hash code is zero (and no other string has hash
353    // code zero) it will always occupy the first entry if present.
354    DescriptorArray* descriptors = obj->map()->instance_descriptors();
355    if ((descriptors->number_of_descriptors() > 0) &&
356        (descriptors->GetKey(0) == Heap::hidden_symbol()) &&
357        descriptors->IsProperty(0)) {
358      ASSERT(descriptors->GetType(0) == FIELD);
359      return Handle<Object>(obj->FastPropertyAt(descriptors->GetFieldIndex(0)));
360    }
361  }
362
363  // Only attempt to find the hidden properties in the local object and not
364  // in the prototype chain.  Note that HasLocalProperty() can cause a GC in
365  // the general case in the presence of interceptors.
366  if (!obj->HasHiddenPropertiesObject()) {
367    // Hidden properties object not found. Allocate a new hidden properties
368    // object if requested. Otherwise return the undefined value.
369    if (create_if_needed) {
370      Handle<Object> hidden_obj = Factory::NewJSObject(Top::object_function());
371      CALL_HEAP_FUNCTION(obj->SetHiddenPropertiesObject(*hidden_obj), Object);
372    } else {
373      return Factory::undefined_value();
374    }
375  }
376  return Handle<Object>(obj->GetHiddenPropertiesObject());
377}
378
379
380Handle<Object> DeleteElement(Handle<JSObject> obj,
381                             uint32_t index) {
382  CALL_HEAP_FUNCTION(obj->DeleteElement(index, JSObject::NORMAL_DELETION),
383                     Object);
384}
385
386
387Handle<Object> DeleteProperty(Handle<JSObject> obj,
388                              Handle<String> prop) {
389  CALL_HEAP_FUNCTION(obj->DeleteProperty(*prop, JSObject::NORMAL_DELETION),
390                     Object);
391}
392
393
394Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index) {
395  CALL_HEAP_FUNCTION(Heap::LookupSingleCharacterStringFromCode(index), Object);
396}
397
398
399Handle<String> SubString(Handle<String> str,
400                         int start,
401                         int end,
402                         PretenureFlag pretenure) {
403  CALL_HEAP_FUNCTION(str->SubString(start, end, pretenure), String);
404}
405
406
407Handle<Object> SetElement(Handle<JSObject> object,
408                          uint32_t index,
409                          Handle<Object> value) {
410  if (object->HasPixelElements() || object->HasExternalArrayElements()) {
411    if (!value->IsSmi() && !value->IsHeapNumber() && !value->IsUndefined()) {
412      bool has_exception;
413      Handle<Object> number = Execution::ToNumber(value, &has_exception);
414      if (has_exception) return Handle<Object>();
415      value = number;
416    }
417  }
418  CALL_HEAP_FUNCTION(object->SetElement(index, *value), Object);
419}
420
421
422Handle<JSObject> Copy(Handle<JSObject> obj) {
423  CALL_HEAP_FUNCTION(Heap::CopyJSObject(*obj), JSObject);
424}
425
426
427Handle<Object> SetAccessor(Handle<JSObject> obj, Handle<AccessorInfo> info) {
428  CALL_HEAP_FUNCTION(obj->DefineAccessor(*info), Object);
429}
430
431
432// Wrappers for scripts are kept alive and cached in weak global
433// handles referred from proxy objects held by the scripts as long as
434// they are used. When they are not used anymore, the garbage
435// collector will call the weak callback on the global handle
436// associated with the wrapper and get rid of both the wrapper and the
437// handle.
438static void ClearWrapperCache(Persistent<v8::Value> handle, void*) {
439#ifdef ENABLE_HEAP_PROTECTION
440  // Weak reference callbacks are called as if from outside V8.  We
441  // need to reeenter to unprotect the heap.
442  VMState state(OTHER);
443#endif
444  Handle<Object> cache = Utils::OpenHandle(*handle);
445  JSValue* wrapper = JSValue::cast(*cache);
446  Proxy* proxy = Script::cast(wrapper->value())->wrapper();
447  ASSERT(proxy->proxy() == reinterpret_cast<Address>(cache.location()));
448  proxy->set_proxy(0);
449  GlobalHandles::Destroy(cache.location());
450  Counters::script_wrappers.Decrement();
451}
452
453
454Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
455  if (script->wrapper()->proxy() != NULL) {
456    // Return the script wrapper directly from the cache.
457    return Handle<JSValue>(
458        reinterpret_cast<JSValue**>(script->wrapper()->proxy()));
459  }
460
461  // Construct a new script wrapper.
462  Counters::script_wrappers.Increment();
463  Handle<JSFunction> constructor = Top::script_function();
464  Handle<JSValue> result =
465      Handle<JSValue>::cast(Factory::NewJSObject(constructor));
466  result->set_value(*script);
467
468  // Create a new weak global handle and use it to cache the wrapper
469  // for future use. The cache will automatically be cleared by the
470  // garbage collector when it is not used anymore.
471  Handle<Object> handle = GlobalHandles::Create(*result);
472  GlobalHandles::MakeWeak(handle.location(), NULL, &ClearWrapperCache);
473  script->wrapper()->set_proxy(reinterpret_cast<Address>(handle.location()));
474  return result;
475}
476
477
478// Init line_ends array with code positions of line ends inside script
479// source.
480void InitScriptLineEnds(Handle<Script> script) {
481  if (!script->line_ends()->IsUndefined()) return;
482
483  if (!script->source()->IsString()) {
484    ASSERT(script->source()->IsUndefined());
485    Handle<FixedArray> empty = Factory::NewFixedArray(0);
486    script->set_line_ends(*empty);
487    ASSERT(script->line_ends()->IsFixedArray());
488    return;
489  }
490
491  Handle<String> src(String::cast(script->source()));
492
493  Handle<FixedArray> array = CalculateLineEnds(src, true);
494
495  script->set_line_ends(*array);
496  ASSERT(script->line_ends()->IsFixedArray());
497}
498
499
500Handle<FixedArray> CalculateLineEnds(Handle<String> src,
501                                     bool with_imaginary_last_new_line) {
502  const int src_len = src->length();
503  Handle<String> new_line = Factory::NewStringFromAscii(CStrVector("\n"));
504
505  // Pass 1: Identify line count.
506  int line_count = 0;
507  int position = 0;
508  while (position != -1 && position < src_len) {
509    position = Runtime::StringMatch(src, new_line, position);
510    if (position != -1) {
511      position++;
512    }
513    if (position != -1) {
514      line_count++;
515    } else if (with_imaginary_last_new_line) {
516      // Even if the last line misses a line end, it is counted.
517      line_count++;
518    }
519  }
520
521  // Pass 2: Fill in line ends positions
522  Handle<FixedArray> array = Factory::NewFixedArray(line_count);
523  int array_index = 0;
524  position = 0;
525  while (position != -1 && position < src_len) {
526    position = Runtime::StringMatch(src, new_line, position);
527    if (position != -1) {
528      array->set(array_index++, Smi::FromInt(position++));
529    } else if (with_imaginary_last_new_line) {
530      // If the script does not end with a line ending add the final end
531      // position as just past the last line ending.
532      array->set(array_index++, Smi::FromInt(src_len));
533    }
534  }
535  ASSERT(array_index == line_count);
536
537  return array;
538}
539
540
541// Convert code position into line number.
542int GetScriptLineNumber(Handle<Script> script, int code_pos) {
543  InitScriptLineEnds(script);
544  AssertNoAllocation no_allocation;
545  FixedArray* line_ends_array = FixedArray::cast(script->line_ends());
546  const int line_ends_len = line_ends_array->length();
547
548  if (!line_ends_len)
549    return -1;
550
551  if ((Smi::cast(line_ends_array->get(0)))->value() >= code_pos)
552    return script->line_offset()->value();
553
554  int left = 0;
555  int right = line_ends_len;
556  while (int half = (right - left) / 2) {
557    if ((Smi::cast(line_ends_array->get(left + half)))->value() > code_pos) {
558      right -= half;
559    } else {
560      left += half;
561    }
562  }
563  return right + script->line_offset()->value();
564}
565
566
567int GetScriptLineNumberSafe(Handle<Script> script, int code_pos) {
568  AssertNoAllocation no_allocation;
569  if (!script->line_ends()->IsUndefined()) {
570    return GetScriptLineNumber(script, code_pos);
571  }
572  // Slow mode: we do not have line_ends. We have to iterate through source.
573  if (!script->source()->IsString()) {
574    return -1;
575  }
576  String* source = String::cast(script->source());
577  int line = 0;
578  int len = source->length();
579  for (int pos = 0; pos < len; pos++) {
580    if (pos == code_pos) {
581      break;
582    }
583    if (source->Get(pos) == '\n') {
584      line++;
585    }
586  }
587  return line;
588}
589
590
591void CustomArguments::IterateInstance(ObjectVisitor* v) {
592  v->VisitPointers(values_, values_ + ARRAY_SIZE(values_));
593}
594
595
596// Compute the property keys from the interceptor.
597v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver,
598                                                 Handle<JSObject> object) {
599  Handle<InterceptorInfo> interceptor(object->GetNamedInterceptor());
600  CustomArguments args(interceptor->data(), *receiver, *object);
601  v8::AccessorInfo info(args.end());
602  v8::Handle<v8::Array> result;
603  if (!interceptor->enumerator()->IsUndefined()) {
604    v8::NamedPropertyEnumerator enum_fun =
605        v8::ToCData<v8::NamedPropertyEnumerator>(interceptor->enumerator());
606    LOG(ApiObjectAccess("interceptor-named-enum", *object));
607    {
608      // Leaving JavaScript.
609      VMState state(EXTERNAL);
610      result = enum_fun(info);
611    }
612  }
613  return result;
614}
615
616
617// Compute the element keys from the interceptor.
618v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSObject> receiver,
619                                                   Handle<JSObject> object) {
620  Handle<InterceptorInfo> interceptor(object->GetIndexedInterceptor());
621  CustomArguments args(interceptor->data(), *receiver, *object);
622  v8::AccessorInfo info(args.end());
623  v8::Handle<v8::Array> result;
624  if (!interceptor->enumerator()->IsUndefined()) {
625    v8::IndexedPropertyEnumerator enum_fun =
626        v8::ToCData<v8::IndexedPropertyEnumerator>(interceptor->enumerator());
627    LOG(ApiObjectAccess("interceptor-indexed-enum", *object));
628    {
629      // Leaving JavaScript.
630      VMState state(EXTERNAL);
631      result = enum_fun(info);
632    }
633  }
634  return result;
635}
636
637
638Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSObject> object,
639                                          KeyCollectionType type) {
640  Handle<FixedArray> content = Factory::empty_fixed_array();
641  Handle<JSObject> arguments_boilerplate =
642      Handle<JSObject>(
643          Top::context()->global_context()->arguments_boilerplate());
644  Handle<JSFunction> arguments_function =
645      Handle<JSFunction>(
646          JSFunction::cast(arguments_boilerplate->map()->constructor()));
647
648  // Only collect keys if access is permitted.
649  for (Handle<Object> p = object;
650       *p != Heap::null_value();
651       p = Handle<Object>(p->GetPrototype())) {
652    Handle<JSObject> current(JSObject::cast(*p));
653
654    // Check access rights if required.
655    if (current->IsAccessCheckNeeded() &&
656        !Top::MayNamedAccess(*current, Heap::undefined_value(),
657                             v8::ACCESS_KEYS)) {
658      Top::ReportFailedAccessCheck(*current, v8::ACCESS_KEYS);
659      break;
660    }
661
662    // Compute the element keys.
663    Handle<FixedArray> element_keys =
664        Factory::NewFixedArray(current->NumberOfEnumElements());
665    current->GetEnumElementKeys(*element_keys);
666    content = UnionOfKeys(content, element_keys);
667
668    // Add the element keys from the interceptor.
669    if (current->HasIndexedInterceptor()) {
670      v8::Handle<v8::Array> result =
671          GetKeysForIndexedInterceptor(object, current);
672      if (!result.IsEmpty())
673        content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
674    }
675
676    // We can cache the computed property keys if access checks are
677    // not needed and no interceptors are involved.
678    //
679    // We do not use the cache if the object has elements and
680    // therefore it does not make sense to cache the property names
681    // for arguments objects.  Arguments objects will always have
682    // elements.
683    // Wrapped strings have elements, but don't have an elements
684    // array or dictionary.  So the fast inline test for whether to
685    // use the cache says yes, so we should not create a cache.
686    bool cache_enum_keys =
687        ((current->map()->constructor() != *arguments_function) &&
688         !current->IsJSValue() &&
689         !current->IsAccessCheckNeeded() &&
690         !current->HasNamedInterceptor() &&
691         !current->HasIndexedInterceptor());
692    // Compute the property keys and cache them if possible.
693    content =
694        UnionOfKeys(content, GetEnumPropertyKeys(current, cache_enum_keys));
695
696    // Add the property keys from the interceptor.
697    if (current->HasNamedInterceptor()) {
698      v8::Handle<v8::Array> result =
699          GetKeysForNamedInterceptor(object, current);
700      if (!result.IsEmpty())
701        content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
702    }
703
704    // If we only want local properties we bail out after the first
705    // iteration.
706    if (type == LOCAL_ONLY)
707      break;
708  }
709  return content;
710}
711
712
713Handle<JSArray> GetKeysFor(Handle<JSObject> object) {
714  Counters::for_in.Increment();
715  Handle<FixedArray> elements = GetKeysInFixedArrayFor(object,
716                                                       INCLUDE_PROTOS);
717  return Factory::NewJSArrayWithElements(elements);
718}
719
720
721Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
722                                       bool cache_result) {
723  int index = 0;
724  if (object->HasFastProperties()) {
725    if (object->map()->instance_descriptors()->HasEnumCache()) {
726      Counters::enum_cache_hits.Increment();
727      DescriptorArray* desc = object->map()->instance_descriptors();
728      return Handle<FixedArray>(FixedArray::cast(desc->GetEnumCache()));
729    }
730    Counters::enum_cache_misses.Increment();
731    int num_enum = object->NumberOfEnumProperties();
732    Handle<FixedArray> storage = Factory::NewFixedArray(num_enum);
733    Handle<FixedArray> sort_array = Factory::NewFixedArray(num_enum);
734    Handle<DescriptorArray> descs =
735        Handle<DescriptorArray>(object->map()->instance_descriptors());
736    for (int i = 0; i < descs->number_of_descriptors(); i++) {
737      if (descs->IsProperty(i) && !descs->IsDontEnum(i)) {
738        (*storage)->set(index, descs->GetKey(i));
739        PropertyDetails details(descs->GetDetails(i));
740        (*sort_array)->set(index, Smi::FromInt(details.index()));
741        index++;
742      }
743    }
744    (*storage)->SortPairs(*sort_array, sort_array->length());
745    if (cache_result) {
746      Handle<FixedArray> bridge_storage =
747          Factory::NewFixedArray(DescriptorArray::kEnumCacheBridgeLength);
748      DescriptorArray* desc = object->map()->instance_descriptors();
749      desc->SetEnumCache(*bridge_storage, *storage);
750    }
751    ASSERT(storage->length() == index);
752    return storage;
753  } else {
754    int num_enum = object->NumberOfEnumProperties();
755    Handle<FixedArray> storage = Factory::NewFixedArray(num_enum);
756    Handle<FixedArray> sort_array = Factory::NewFixedArray(num_enum);
757    object->property_dictionary()->CopyEnumKeysTo(*storage, *sort_array);
758    return storage;
759  }
760}
761
762
763bool EnsureCompiled(Handle<SharedFunctionInfo> shared,
764                    ClearExceptionFlag flag) {
765  return shared->is_compiled() || CompileLazyShared(shared, flag);
766}
767
768
769static bool CompileLazyHelper(CompilationInfo* info,
770                              ClearExceptionFlag flag) {
771  // Compile the source information to a code object.
772  ASSERT(!info->shared_info()->is_compiled());
773  bool result = Compiler::CompileLazy(info);
774  ASSERT(result != Top::has_pending_exception());
775  if (!result && flag == CLEAR_EXCEPTION) Top::clear_pending_exception();
776  return result;
777}
778
779
780bool CompileLazyShared(Handle<SharedFunctionInfo> shared,
781                       ClearExceptionFlag flag) {
782  CompilationInfo info(shared);
783  return CompileLazyHelper(&info, flag);
784}
785
786
787bool CompileLazy(Handle<JSFunction> function,
788                 Handle<Object> receiver,
789                 ClearExceptionFlag flag) {
790  if (function->shared()->is_compiled()) {
791    function->set_code(function->shared()->code());
792    function->shared()->set_code_age(0);
793    return true;
794  } else {
795    CompilationInfo info(function, 0, receiver);
796    bool result = CompileLazyHelper(&info, flag);
797    PROFILE(FunctionCreateEvent(*function));
798    return result;
799  }
800}
801
802
803bool CompileLazyInLoop(Handle<JSFunction> function,
804                       Handle<Object> receiver,
805                       ClearExceptionFlag flag) {
806  if (function->shared()->is_compiled()) {
807    function->set_code(function->shared()->code());
808    function->shared()->set_code_age(0);
809    return true;
810  } else {
811    CompilationInfo info(function, 1, receiver);
812    bool result = CompileLazyHelper(&info, flag);
813    PROFILE(FunctionCreateEvent(*function));
814    return result;
815  }
816}
817
818
819OptimizedObjectForAddingMultipleProperties::
820OptimizedObjectForAddingMultipleProperties(Handle<JSObject> object,
821                                           int expected_additional_properties,
822                                           bool condition) {
823  object_ = object;
824  if (condition && object_->HasFastProperties()) {
825    // Normalize the properties of object to avoid n^2 behavior
826    // when extending the object multiple properties. Indicate the number of
827    // properties to be added.
828    unused_property_fields_ = object->map()->unused_property_fields();
829    NormalizeProperties(object_,
830                        KEEP_INOBJECT_PROPERTIES,
831                        expected_additional_properties);
832    has_been_transformed_ = true;
833
834  } else {
835    has_been_transformed_ = false;
836  }
837}
838
839
840OptimizedObjectForAddingMultipleProperties::
841~OptimizedObjectForAddingMultipleProperties() {
842  // Reoptimize the object to allow fast property access.
843  if (has_been_transformed_) {
844    TransformToFastProperties(object_, unused_property_fields_);
845  }
846}
847
848} }  // namespace v8::internal
849