handles.cc revision b0fe1620dcb4135ac3ab2d66ff93072373911299 
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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14//       from this software without specific prior written permission.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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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 "string-search.h"
41#include "stub-cache.h"
42#include "vm-state-inl.h"
43
44namespace v8 {
45namespace internal {
46
47
48v8::ImplementationUtilities::HandleScopeData HandleScope::current_ =
49    { NULL, NULL, 0 };
50
51
52int HandleScope::NumberOfHandles() {
53  int n = HandleScopeImplementer::instance()->blocks()->length();
54  if (n == 0) return 0;
55  return ((n - 1) * kHandleBlockSize) + static_cast<int>(
56      (current_.next - HandleScopeImplementer::instance()->blocks()->last()));
57}
58
59
60Object** HandleScope::Extend() {
61  Object** result = current_.next;
62
63  ASSERT(result == current_.limit);
64  // Make sure there's at least one scope on the stack and that the
65  // top of the scope stack isn't a barrier.
66  if (current_.level == 0) {
67    Utils::ReportApiFailure("v8::HandleScope::CreateHandle()",
68                            "Cannot create a handle without a HandleScope");
69    return NULL;
70  }
71  HandleScopeImplementer* impl = HandleScopeImplementer::instance();
72  // If there's more room in the last block, we use that. This is used
73  // for fast creation of scopes after scope barriers.
74  if (!impl->blocks()->is_empty()) {
75    Object** limit = &impl->blocks()->last()[kHandleBlockSize];
76    if (current_.limit != limit) {
77      current_.limit = limit;
78      ASSERT(limit - current_.next < kHandleBlockSize);
79    }
80  }
81
82  // If we still haven't found a slot for the handle, we extend the
83  // current handle scope by allocating a new handle block.
84  if (result == current_.limit) {
85    // If there's a spare block, use it for growing the current scope.
86    result = impl->GetSpareOrNewBlock();
87    // Add the extension to the global list of blocks, but count the
88    // extension as part of the current scope.
89    impl->blocks()->Add(result);
90    current_.limit = &result[kHandleBlockSize];
91  }
92
93  return result;
94}
95
96
97void HandleScope::DeleteExtensions() {
98  HandleScopeImplementer::instance()->DeleteExtensions(current_.limit);
99}
100
101
102void HandleScope::ZapRange(Object** start, Object** end) {
103  ASSERT(end - start <= kHandleBlockSize);
104  for (Object** p = start; p != end; p++) {
105    *reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
106  }
107}
108
109
110Address HandleScope::current_level_address() {
111  return reinterpret_cast<Address>(&current_.level);
112}
113
114
115Address HandleScope::current_next_address() {
116  return reinterpret_cast<Address>(&current_.next);
117}
118
119
120Address HandleScope::current_limit_address() {
121  return reinterpret_cast<Address>(&current_.limit);
122}
123
124
125Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray> content,
126                                      Handle<JSArray> array) {
127  CALL_HEAP_FUNCTION(content->AddKeysFromJSArray(*array), FixedArray);
128}
129
130
131Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
132                               Handle<FixedArray> second) {
133  CALL_HEAP_FUNCTION(first->UnionOfKeys(*second), FixedArray);
134}
135
136
137Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
138    Handle<JSFunction> constructor,
139    Handle<JSGlobalProxy> global) {
140  CALL_HEAP_FUNCTION(Heap::ReinitializeJSGlobalProxy(*constructor, *global),
141                     JSGlobalProxy);
142}
143
144
145void SetExpectedNofProperties(Handle<JSFunction> func, int nof) {
146  // If objects constructed from this function exist then changing
147  // 'estimated_nof_properties' is dangerous since the previous value might
148  // have been compiled into the fast construct stub. More over, the inobject
149  // slack tracking logic might have adjusted the previous value, so even
150  // passing the same value is risky.
151  if (func->shared()->live_objects_may_exist()) return;
152
153  func->shared()->set_expected_nof_properties(nof);
154  if (func->has_initial_map()) {
155    Handle<Map> new_initial_map =
156        Factory::CopyMapDropTransitions(Handle<Map>(func->initial_map()));
157    new_initial_map->set_unused_property_fields(nof);
158    func->set_initial_map(*new_initial_map);
159  }
160}
161
162
163void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value) {
164  CALL_HEAP_FUNCTION_VOID(func->SetPrototype(*value));
165}
166
167
168static int ExpectedNofPropertiesFromEstimate(int estimate) {
169  // If no properties are added in the constructor, they are more likely
170  // to be added later.
171  if (estimate == 0) estimate = 2;
172
173  // We do not shrink objects that go into a snapshot (yet), so we adjust
174  // the estimate conservatively.
175  if (Serializer::enabled()) return estimate + 2;
176
177  // Inobject slack tracking will reclaim redundant inobject space later,
178  // so we can afford to adjust the estimate generously.
179  return estimate + 8;
180}
181
182
183void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
184                                          int estimate) {
185  // See the comment in SetExpectedNofProperties.
186  if (shared->live_objects_may_exist()) return;
187
188  shared->set_expected_nof_properties(
189      ExpectedNofPropertiesFromEstimate(estimate));
190}
191
192
193void NormalizeProperties(Handle<JSObject> object,
194                         PropertyNormalizationMode mode,
195                         int expected_additional_properties) {
196  CALL_HEAP_FUNCTION_VOID(object->NormalizeProperties(
197      mode,
198      expected_additional_properties));
199}
200
201
202void NormalizeElements(Handle<JSObject> object) {
203  CALL_HEAP_FUNCTION_VOID(object->NormalizeElements());
204}
205
206
207void TransformToFastProperties(Handle<JSObject> object,
208                               int unused_property_fields) {
209  CALL_HEAP_FUNCTION_VOID(
210      object->TransformToFastProperties(unused_property_fields));
211}
212
213
214void NumberDictionarySet(Handle<NumberDictionary> dictionary,
215                         uint32_t index,
216                         Handle<Object> value,
217                         PropertyDetails details) {
218  CALL_HEAP_FUNCTION_VOID(dictionary->Set(index, *value, details));
219}
220
221
222void FlattenString(Handle<String> string) {
223  CALL_HEAP_FUNCTION_VOID(string->TryFlatten());
224}
225
226
227Handle<String> FlattenGetString(Handle<String> string) {
228  CALL_HEAP_FUNCTION(string->TryFlatten(), String);
229}
230
231
232Handle<Object> SetPrototype(Handle<JSFunction> function,
233                            Handle<Object> prototype) {
234  ASSERT(function->should_have_prototype());
235  CALL_HEAP_FUNCTION(Accessors::FunctionSetPrototype(*function,
236                                                     *prototype,
237                                                     NULL),
238                     Object);
239}
240
241
242Handle<Object> SetProperty(Handle<JSObject> object,
243                           Handle<String> key,
244                           Handle<Object> value,
245                           PropertyAttributes attributes) {
246  CALL_HEAP_FUNCTION(object->SetProperty(*key, *value, attributes), Object);
247}
248
249
250Handle<Object> SetProperty(Handle<Object> object,
251                           Handle<Object> key,
252                           Handle<Object> value,
253                           PropertyAttributes attributes) {
254  CALL_HEAP_FUNCTION(
255      Runtime::SetObjectProperty(object, key, value, attributes), Object);
256}
257
258
259Handle<Object> ForceSetProperty(Handle<JSObject> object,
260                                Handle<Object> key,
261                                Handle<Object> value,
262                                PropertyAttributes attributes) {
263  CALL_HEAP_FUNCTION(
264      Runtime::ForceSetObjectProperty(object, key, value, attributes), Object);
265}
266
267
268Handle<Object> SetNormalizedProperty(Handle<JSObject> object,
269                                     Handle<String> key,
270                                     Handle<Object> value,
271                                     PropertyDetails details) {
272  CALL_HEAP_FUNCTION(object->SetNormalizedProperty(*key, *value, details),
273                     Object);
274}
275
276
277Handle<Object> ForceDeleteProperty(Handle<JSObject> object,
278                                   Handle<Object> key) {
279  CALL_HEAP_FUNCTION(Runtime::ForceDeleteObjectProperty(object, key), Object);
280}
281
282
283Handle<Object> IgnoreAttributesAndSetLocalProperty(
284    Handle<JSObject> object,
285    Handle<String> key,
286    Handle<Object> value,
287    PropertyAttributes attributes) {
288  CALL_HEAP_FUNCTION(object->
289      IgnoreAttributesAndSetLocalProperty(*key, *value, attributes), Object);
290}
291
292
293Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object,
294                                          Handle<String> key,
295                                          Handle<Object> value,
296                                          PropertyAttributes attributes) {
297  CALL_HEAP_FUNCTION(object->SetPropertyWithInterceptor(*key,
298                                                        *value,
299                                                        attributes),
300                     Object);
301}
302
303
304Handle<Object> GetProperty(Handle<JSObject> obj,
305                           const char* name) {
306  Handle<String> str = Factory::LookupAsciiSymbol(name);
307  CALL_HEAP_FUNCTION(obj->GetProperty(*str), Object);
308}
309
310
311Handle<Object> GetProperty(Handle<Object> obj,
312                           Handle<Object> key) {
313  CALL_HEAP_FUNCTION(Runtime::GetObjectProperty(obj, key), Object);
314}
315
316
317Handle<Object> GetElement(Handle<Object> obj,
318                          uint32_t index) {
319  CALL_HEAP_FUNCTION(Runtime::GetElement(obj, index), Object);
320}
321
322
323Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
324                                          Handle<JSObject> holder,
325                                          Handle<String> name,
326                                          PropertyAttributes* attributes) {
327  CALL_HEAP_FUNCTION(holder->GetPropertyWithInterceptor(*receiver,
328                                                        *name,
329                                                        attributes),
330                     Object);
331}
332
333
334Handle<Object> GetPrototype(Handle<Object> obj) {
335  Handle<Object> result(obj->GetPrototype());
336  return result;
337}
338
339
340Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value) {
341  const bool skip_hidden_prototypes = false;
342  CALL_HEAP_FUNCTION(obj->SetPrototype(*value, skip_hidden_prototypes), Object);
343}
344
345
346Handle<Object> GetHiddenProperties(Handle<JSObject> obj,
347                                   bool create_if_needed) {
348  Object* holder = obj->BypassGlobalProxy();
349  if (holder->IsUndefined()) return Factory::undefined_value();
350  obj = Handle<JSObject>(JSObject::cast(holder));
351
352  if (obj->HasFastProperties()) {
353    // If the object has fast properties, check whether the first slot
354    // in the descriptor array matches the hidden symbol. Since the
355    // hidden symbols hash code is zero (and no other string has hash
356    // code zero) it will always occupy the first entry if present.
357    DescriptorArray* descriptors = obj->map()->instance_descriptors();
358    if ((descriptors->number_of_descriptors() > 0) &&
359        (descriptors->GetKey(0) == Heap::hidden_symbol()) &&
360        descriptors->IsProperty(0)) {
361      ASSERT(descriptors->GetType(0) == FIELD);
362      return Handle<Object>(obj->FastPropertyAt(descriptors->GetFieldIndex(0)));
363    }
364  }
365
366  // Only attempt to find the hidden properties in the local object and not
367  // in the prototype chain.  Note that HasLocalProperty() can cause a GC in
368  // the general case in the presence of interceptors.
369  if (!obj->HasHiddenPropertiesObject()) {
370    // Hidden properties object not found. Allocate a new hidden properties
371    // object if requested. Otherwise return the undefined value.
372    if (create_if_needed) {
373      Handle<Object> hidden_obj = Factory::NewJSObject(Top::object_function());
374      CALL_HEAP_FUNCTION(obj->SetHiddenPropertiesObject(*hidden_obj), Object);
375    } else {
376      return Factory::undefined_value();
377    }
378  }
379  return Handle<Object>(obj->GetHiddenPropertiesObject());
380}
381
382
383Handle<Object> DeleteElement(Handle<JSObject> obj,
384                             uint32_t index) {
385  CALL_HEAP_FUNCTION(obj->DeleteElement(index, JSObject::NORMAL_DELETION),
386                     Object);
387}
388
389
390Handle<Object> DeleteProperty(Handle<JSObject> obj,
391                              Handle<String> prop) {
392  CALL_HEAP_FUNCTION(obj->DeleteProperty(*prop, JSObject::NORMAL_DELETION),
393                     Object);
394}
395
396
397Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index) {
398  CALL_HEAP_FUNCTION(Heap::LookupSingleCharacterStringFromCode(index), Object);
399}
400
401
402Handle<String> SubString(Handle<String> str,
403                         int start,
404                         int end,
405                         PretenureFlag pretenure) {
406  CALL_HEAP_FUNCTION(str->SubString(start, end, pretenure), String);
407}
408
409
410Handle<Object> SetElement(Handle<JSObject> object,
411                          uint32_t index,
412                          Handle<Object> value) {
413  if (object->HasPixelElements() || object->HasExternalArrayElements()) {
414    if (!value->IsSmi() && !value->IsHeapNumber() && !value->IsUndefined()) {
415      bool has_exception;
416      Handle<Object> number = Execution::ToNumber(value, &has_exception);
417      if (has_exception) return Handle<Object>();
418      value = number;
419    }
420  }
421  CALL_HEAP_FUNCTION(object->SetElement(index, *value), Object);
422}
423
424
425Handle<JSObject> Copy(Handle<JSObject> obj) {
426  CALL_HEAP_FUNCTION(Heap::CopyJSObject(*obj), JSObject);
427}
428
429
430Handle<Object> SetAccessor(Handle<JSObject> obj, Handle<AccessorInfo> info) {
431  CALL_HEAP_FUNCTION(obj->DefineAccessor(*info), Object);
432}
433
434
435// Wrappers for scripts are kept alive and cached in weak global
436// handles referred from proxy objects held by the scripts as long as
437// they are used. When they are not used anymore, the garbage
438// collector will call the weak callback on the global handle
439// associated with the wrapper and get rid of both the wrapper and the
440// handle.
441static void ClearWrapperCache(Persistent<v8::Value> handle, void*) {
442#ifdef ENABLE_HEAP_PROTECTION
443  // Weak reference callbacks are called as if from outside V8.  We
444  // need to reeenter to unprotect the heap.
445  VMState state(OTHER);
446#endif
447  Handle<Object> cache = Utils::OpenHandle(*handle);
448  JSValue* wrapper = JSValue::cast(*cache);
449  Proxy* proxy = Script::cast(wrapper->value())->wrapper();
450  ASSERT(proxy->proxy() == reinterpret_cast<Address>(cache.location()));
451  proxy->set_proxy(0);
452  GlobalHandles::Destroy(cache.location());
453  Counters::script_wrappers.Decrement();
454}
455
456
457Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
458  if (script->wrapper()->proxy() != NULL) {
459    // Return the script wrapper directly from the cache.
460    return Handle<JSValue>(
461        reinterpret_cast<JSValue**>(script->wrapper()->proxy()));
462  }
463
464  // Construct a new script wrapper.
465  Counters::script_wrappers.Increment();
466  Handle<JSFunction> constructor = Top::script_function();
467  Handle<JSValue> result =
468      Handle<JSValue>::cast(Factory::NewJSObject(constructor));
469  result->set_value(*script);
470
471  // Create a new weak global handle and use it to cache the wrapper
472  // for future use. The cache will automatically be cleared by the
473  // garbage collector when it is not used anymore.
474  Handle<Object> handle = GlobalHandles::Create(*result);
475  GlobalHandles::MakeWeak(handle.location(), NULL, &ClearWrapperCache);
476  script->wrapper()->set_proxy(reinterpret_cast<Address>(handle.location()));
477  return result;
478}
479
480
481// Init line_ends array with code positions of line ends inside script
482// source.
483void InitScriptLineEnds(Handle<Script> script) {
484  if (!script->line_ends()->IsUndefined()) return;
485
486  if (!script->source()->IsString()) {
487    ASSERT(script->source()->IsUndefined());
488    Handle<FixedArray> empty = Factory::NewFixedArray(0);
489    script->set_line_ends(*empty);
490    ASSERT(script->line_ends()->IsFixedArray());
491    return;
492  }
493
494  Handle<String> src(String::cast(script->source()));
495
496  Handle<FixedArray> array = CalculateLineEnds(src, true);
497
498  if (*array != Heap::empty_fixed_array()) {
499    array->set_map(Heap::fixed_cow_array_map());
500  }
501
502  script->set_line_ends(*array);
503  ASSERT(script->line_ends()->IsFixedArray());
504}
505
506
507template <typename SourceChar>
508static void CalculateLineEnds(List<int>* line_ends,
509                              Vector<const SourceChar> src,
510                              bool with_last_line) {
511  const int src_len = src.length();
512  StringSearch<char, SourceChar> search(CStrVector("\n"));
513
514  // Find and record line ends.
515  int position = 0;
516  while (position != -1 && position < src_len) {
517    position = search.Search(src, position);
518    if (position != -1) {
519      line_ends->Add(position);
520      position++;
521    } else if (with_last_line) {
522      // Even if the last line misses a line end, it is counted.
523      line_ends->Add(src_len);
524      return;
525    }
526  }
527}
528
529
530Handle<FixedArray> CalculateLineEnds(Handle<String> src,
531                                     bool with_last_line) {
532  src = FlattenGetString(src);
533  // Rough estimate of line count based on a roughly estimated average
534  // length of (unpacked) code.
535  int line_count_estimate = src->length() >> 4;
536  List<int> line_ends(line_count_estimate);
537  {
538    AssertNoAllocation no_heap_allocation;  // ensure vectors stay valid.
539    // Dispatch on type of strings.
540    if (src->IsAsciiRepresentation()) {
541      CalculateLineEnds(&line_ends, src->ToAsciiVector(), with_last_line);
542    } else {
543      CalculateLineEnds(&line_ends, src->ToUC16Vector(), with_last_line);
544    }
545  }
546  int line_count = line_ends.length();
547  Handle<FixedArray> array = Factory::NewFixedArray(line_count);
548  for (int i = 0; i < line_count; i++) {
549    array->set(i, Smi::FromInt(line_ends[i]));
550  }
551  return array;
552}
553
554
555// Convert code position into line number.
556int GetScriptLineNumber(Handle<Script> script, int code_pos) {
557  InitScriptLineEnds(script);
558  AssertNoAllocation no_allocation;
559  FixedArray* line_ends_array = FixedArray::cast(script->line_ends());
560  const int line_ends_len = line_ends_array->length();
561
562  if (!line_ends_len) return -1;
563
564  if ((Smi::cast(line_ends_array->get(0)))->value() >= code_pos) {
565    return script->line_offset()->value();
566  }
567
568  int left = 0;
569  int right = line_ends_len;
570  while (int half = (right - left) / 2) {
571    if ((Smi::cast(line_ends_array->get(left + half)))->value() > code_pos) {
572      right -= half;
573    } else {
574      left += half;
575    }
576  }
577  return right + script->line_offset()->value();
578}
579
580
581int GetScriptLineNumberSafe(Handle<Script> script, int code_pos) {
582  AssertNoAllocation no_allocation;
583  if (!script->line_ends()->IsUndefined()) {
584    return GetScriptLineNumber(script, code_pos);
585  }
586  // Slow mode: we do not have line_ends. We have to iterate through source.
587  if (!script->source()->IsString()) {
588    return -1;
589  }
590  String* source = String::cast(script->source());
591  int line = 0;
592  int len = source->length();
593  for (int pos = 0; pos < len; pos++) {
594    if (pos == code_pos) {
595      break;
596    }
597    if (source->Get(pos) == '\n') {
598      line++;
599    }
600  }
601  return line;
602}
603
604
605void CustomArguments::IterateInstance(ObjectVisitor* v) {
606  v->VisitPointers(values_, values_ + ARRAY_SIZE(values_));
607}
608
609
610// Compute the property keys from the interceptor.
611v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver,
612                                                 Handle<JSObject> object) {
613  Handle<InterceptorInfo> interceptor(object->GetNamedInterceptor());
614  CustomArguments args(interceptor->data(), *receiver, *object);
615  v8::AccessorInfo info(args.end());
616  v8::Handle<v8::Array> result;
617  if (!interceptor->enumerator()->IsUndefined()) {
618    v8::NamedPropertyEnumerator enum_fun =
619        v8::ToCData<v8::NamedPropertyEnumerator>(interceptor->enumerator());
620    LOG(ApiObjectAccess("interceptor-named-enum", *object));
621    {
622      // Leaving JavaScript.
623      VMState state(EXTERNAL);
624      result = enum_fun(info);
625    }
626  }
627  return result;
628}
629
630
631// Compute the element keys from the interceptor.
632v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSObject> receiver,
633                                                   Handle<JSObject> object) {
634  Handle<InterceptorInfo> interceptor(object->GetIndexedInterceptor());
635  CustomArguments args(interceptor->data(), *receiver, *object);
636  v8::AccessorInfo info(args.end());
637  v8::Handle<v8::Array> result;
638  if (!interceptor->enumerator()->IsUndefined()) {
639    v8::IndexedPropertyEnumerator enum_fun =
640        v8::ToCData<v8::IndexedPropertyEnumerator>(interceptor->enumerator());
641    LOG(ApiObjectAccess("interceptor-indexed-enum", *object));
642    {
643      // Leaving JavaScript.
644      VMState state(EXTERNAL);
645      result = enum_fun(info);
646    }
647  }
648  return result;
649}
650
651
652static bool ContainsOnlyValidKeys(Handle<FixedArray> array) {
653  int len = array->length();
654  for (int i = 0; i < len; i++) {
655    Object* e = array->get(i);
656    if (!(e->IsString() || e->IsNumber())) return false;
657  }
658  return true;
659}
660
661
662Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSObject> object,
663                                          KeyCollectionType type) {
664  USE(ContainsOnlyValidKeys);
665  Handle<FixedArray> content = Factory::empty_fixed_array();
666  Handle<JSObject> arguments_boilerplate =
667      Handle<JSObject>(
668          Top::context()->global_context()->arguments_boilerplate());
669  Handle<JSFunction> arguments_function =
670      Handle<JSFunction>(
671          JSFunction::cast(arguments_boilerplate->map()->constructor()));
672
673  // Only collect keys if access is permitted.
674  for (Handle<Object> p = object;
675       *p != Heap::null_value();
676       p = Handle<Object>(p->GetPrototype())) {
677    Handle<JSObject> current(JSObject::cast(*p));
678
679    // Check access rights if required.
680    if (current->IsAccessCheckNeeded() &&
681        !Top::MayNamedAccess(*current, Heap::undefined_value(),
682                             v8::ACCESS_KEYS)) {
683      Top::ReportFailedAccessCheck(*current, v8::ACCESS_KEYS);
684      break;
685    }
686
687    // Compute the element keys.
688    Handle<FixedArray> element_keys =
689        Factory::NewFixedArray(current->NumberOfEnumElements());
690    current->GetEnumElementKeys(*element_keys);
691    content = UnionOfKeys(content, element_keys);
692    ASSERT(ContainsOnlyValidKeys(content));
693
694    // Add the element keys from the interceptor.
695    if (current->HasIndexedInterceptor()) {
696      v8::Handle<v8::Array> result =
697          GetKeysForIndexedInterceptor(object, current);
698      if (!result.IsEmpty())
699        content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
700      ASSERT(ContainsOnlyValidKeys(content));
701    }
702
703    // We can cache the computed property keys if access checks are
704    // not needed and no interceptors are involved.
705    //
706    // We do not use the cache if the object has elements and
707    // therefore it does not make sense to cache the property names
708    // for arguments objects.  Arguments objects will always have
709    // elements.
710    // Wrapped strings have elements, but don't have an elements
711    // array or dictionary.  So the fast inline test for whether to
712    // use the cache says yes, so we should not create a cache.
713    bool cache_enum_keys =
714        ((current->map()->constructor() != *arguments_function) &&
715         !current->IsJSValue() &&
716         !current->IsAccessCheckNeeded() &&
717         !current->HasNamedInterceptor() &&
718         !current->HasIndexedInterceptor());
719    // Compute the property keys and cache them if possible.
720    content =
721        UnionOfKeys(content, GetEnumPropertyKeys(current, cache_enum_keys));
722    ASSERT(ContainsOnlyValidKeys(content));
723
724    // Add the property keys from the interceptor.
725    if (current->HasNamedInterceptor()) {
726      v8::Handle<v8::Array> result =
727          GetKeysForNamedInterceptor(object, current);
728      if (!result.IsEmpty())
729        content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
730      ASSERT(ContainsOnlyValidKeys(content));
731    }
732
733    // If we only want local properties we bail out after the first
734    // iteration.
735    if (type == LOCAL_ONLY)
736      break;
737  }
738  return content;
739}
740
741
742Handle<JSArray> GetKeysFor(Handle<JSObject> object) {
743  Counters::for_in.Increment();
744  Handle<FixedArray> elements = GetKeysInFixedArrayFor(object,
745                                                       INCLUDE_PROTOS);
746  return Factory::NewJSArrayWithElements(elements);
747}
748
749
750Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
751                                       bool cache_result) {
752  int index = 0;
753  if (object->HasFastProperties()) {
754    if (object->map()->instance_descriptors()->HasEnumCache()) {
755      Counters::enum_cache_hits.Increment();
756      DescriptorArray* desc = object->map()->instance_descriptors();
757      return Handle<FixedArray>(FixedArray::cast(desc->GetEnumCache()));
758    }
759    Counters::enum_cache_misses.Increment();
760    int num_enum = object->NumberOfEnumProperties();
761    Handle<FixedArray> storage = Factory::NewFixedArray(num_enum);
762    Handle<FixedArray> sort_array = Factory::NewFixedArray(num_enum);
763    Handle<DescriptorArray> descs =
764        Handle<DescriptorArray>(object->map()->instance_descriptors());
765    for (int i = 0; i < descs->number_of_descriptors(); i++) {
766      if (descs->IsProperty(i) && !descs->IsDontEnum(i)) {
767        (*storage)->set(index, descs->GetKey(i));
768        PropertyDetails details(descs->GetDetails(i));
769        (*sort_array)->set(index, Smi::FromInt(details.index()));
770        index++;
771      }
772    }
773    (*storage)->SortPairs(*sort_array, sort_array->length());
774    if (cache_result) {
775      Handle<FixedArray> bridge_storage =
776          Factory::NewFixedArray(DescriptorArray::kEnumCacheBridgeLength);
777      DescriptorArray* desc = object->map()->instance_descriptors();
778      desc->SetEnumCache(*bridge_storage, *storage);
779    }
780    ASSERT(storage->length() == index);
781    return storage;
782  } else {
783    int num_enum = object->NumberOfEnumProperties();
784    Handle<FixedArray> storage = Factory::NewFixedArray(num_enum);
785    Handle<FixedArray> sort_array = Factory::NewFixedArray(num_enum);
786    object->property_dictionary()->CopyEnumKeysTo(*storage, *sort_array);
787    return storage;
788  }
789}
790
791
792bool EnsureCompiled(Handle<SharedFunctionInfo> shared,
793                    ClearExceptionFlag flag) {
794  return shared->is_compiled() || CompileLazyShared(shared, flag);
795}
796
797
798static bool CompileLazyHelper(CompilationInfo* info,
799                              ClearExceptionFlag flag) {
800  // Compile the source information to a code object.
801  ASSERT(info->IsOptimizing() || !info->shared_info()->is_compiled());
802  bool result = Compiler::CompileLazy(info);
803  ASSERT(result != Top::has_pending_exception());
804  if (!result && flag == CLEAR_EXCEPTION) Top::clear_pending_exception();
805  return result;
806}
807
808
809bool CompileLazyShared(Handle<SharedFunctionInfo> shared,
810                       ClearExceptionFlag flag) {
811  CompilationInfo info(shared);
812  return CompileLazyHelper(&info, flag);
813}
814
815
816bool CompileLazy(Handle<JSFunction> function,
817                 ClearExceptionFlag flag) {
818  bool result = true;
819  if (function->shared()->is_compiled()) {
820    function->ReplaceCode(function->shared()->code());
821    function->shared()->set_code_age(0);
822  } else {
823    CompilationInfo info(function);
824    result = CompileLazyHelper(&info, flag);
825    ASSERT(!result || function->is_compiled());
826  }
827  if (result && function->is_compiled()) {
828    PROFILE(FunctionCreateEvent(*function));
829  }
830  return result;
831}
832
833
834bool CompileLazyInLoop(Handle<JSFunction> function,
835                       ClearExceptionFlag flag) {
836  bool result = true;
837  if (function->shared()->is_compiled()) {
838    function->ReplaceCode(function->shared()->code());
839    function->shared()->set_code_age(0);
840  } else {
841    CompilationInfo info(function);
842    info.MarkAsInLoop();
843    result = CompileLazyHelper(&info, flag);
844    ASSERT(!result || function->is_compiled());
845  }
846  if (result && function->is_compiled()) {
847    PROFILE(FunctionCreateEvent(*function));
848  }
849  return result;
850}
851
852
853bool CompileOptimized(Handle<JSFunction> function, int osr_ast_id) {
854  CompilationInfo info(function);
855  info.SetOptimizing(osr_ast_id);
856  bool result = CompileLazyHelper(&info, KEEP_EXCEPTION);
857  if (result) PROFILE(FunctionCreateEvent(*function));
858  return result;
859}
860
861
862OptimizedObjectForAddingMultipleProperties::
863OptimizedObjectForAddingMultipleProperties(Handle<JSObject> object,
864                                           int expected_additional_properties,
865                                           bool condition) {
866  object_ = object;
867  if (condition && object_->HasFastProperties()) {
868    // Normalize the properties of object to avoid n^2 behavior
869    // when extending the object multiple properties. Indicate the number of
870    // properties to be added.
871    unused_property_fields_ = object->map()->unused_property_fields();
872    NormalizeProperties(object_,
873                        KEEP_INOBJECT_PROPERTIES,
874                        expected_additional_properties);
875    has_been_transformed_ = true;
876
877  } else {
878    has_been_transformed_ = false;
879  }
880}
881
882
883OptimizedObjectForAddingMultipleProperties::
884~OptimizedObjectForAddingMultipleProperties() {
885  // Reoptimize the object to allow fast property access.
886  if (has_been_transformed_) {
887    TransformToFastProperties(object_, unused_property_fields_);
888  }
889}
890
891} }  // namespace v8::internal
892