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      1 // Copyright 2009 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      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
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     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
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     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,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     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 
     44 namespace v8 {
     45 namespace internal {
     46 
     47 
     48 int HandleScope::NumberOfHandles() {
     49   Isolate* isolate = Isolate::Current();
     50   HandleScopeImplementer* impl = isolate->handle_scope_implementer();
     51   int n = impl->blocks()->length();
     52   if (n == 0) return 0;
     53   return ((n - 1) * kHandleBlockSize) + static_cast<int>(
     54       (isolate->handle_scope_data()->next - impl->blocks()->last()));
     55 }
     56 
     57 
     58 Object** HandleScope::Extend() {
     59   Isolate* isolate = Isolate::Current();
     60   v8::ImplementationUtilities::HandleScopeData* current =
     61       isolate->handle_scope_data();
     62 
     63   Object** result = current->next;
     64 
     65   ASSERT(result == current->limit);
     66   // Make sure there's at least one scope on the stack and that the
     67   // top of the scope stack isn't a barrier.
     68   if (current->level == 0) {
     69     Utils::ReportApiFailure("v8::HandleScope::CreateHandle()",
     70                             "Cannot create a handle without a HandleScope");
     71     return NULL;
     72   }
     73   HandleScopeImplementer* impl = isolate->handle_scope_implementer();
     74   // If there's more room in the last block, we use that. This is used
     75   // for fast creation of scopes after scope barriers.
     76   if (!impl->blocks()->is_empty()) {
     77     Object** limit = &impl->blocks()->last()[kHandleBlockSize];
     78     if (current->limit != limit) {
     79       current->limit = limit;
     80       ASSERT(limit - current->next < kHandleBlockSize);
     81     }
     82   }
     83 
     84   // If we still haven't found a slot for the handle, we extend the
     85   // current handle scope by allocating a new handle block.
     86   if (result == current->limit) {
     87     // If there's a spare block, use it for growing the current scope.
     88     result = impl->GetSpareOrNewBlock();
     89     // Add the extension to the global list of blocks, but count the
     90     // extension as part of the current scope.
     91     impl->blocks()->Add(result);
     92     current->limit = &result[kHandleBlockSize];
     93   }
     94 
     95   return result;
     96 }
     97 
     98 
     99 void HandleScope::DeleteExtensions(Isolate* isolate) {
    100   ASSERT(isolate == Isolate::Current());
    101   v8::ImplementationUtilities::HandleScopeData* current =
    102       isolate->handle_scope_data();
    103   isolate->handle_scope_implementer()->DeleteExtensions(current->limit);
    104 }
    105 
    106 
    107 void HandleScope::ZapRange(Object** start, Object** end) {
    108   ASSERT(end - start <= kHandleBlockSize);
    109   for (Object** p = start; p != end; p++) {
    110     *reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
    111   }
    112 }
    113 
    114 
    115 Address HandleScope::current_level_address() {
    116   return reinterpret_cast<Address>(
    117       &Isolate::Current()->handle_scope_data()->level);
    118 }
    119 
    120 
    121 Address HandleScope::current_next_address() {
    122   return reinterpret_cast<Address>(
    123       &Isolate::Current()->handle_scope_data()->next);
    124 }
    125 
    126 
    127 Address HandleScope::current_limit_address() {
    128   return reinterpret_cast<Address>(
    129       &Isolate::Current()->handle_scope_data()->limit);
    130 }
    131 
    132 
    133 Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray> content,
    134                                       Handle<JSArray> array) {
    135   CALL_HEAP_FUNCTION(content->GetIsolate(),
    136                      content->AddKeysFromJSArray(*array), FixedArray);
    137 }
    138 
    139 
    140 Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
    141                                Handle<FixedArray> second) {
    142   CALL_HEAP_FUNCTION(first->GetIsolate(),
    143                      first->UnionOfKeys(*second), FixedArray);
    144 }
    145 
    146 
    147 Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
    148     Handle<JSFunction> constructor,
    149     Handle<JSGlobalProxy> global) {
    150   CALL_HEAP_FUNCTION(
    151       constructor->GetIsolate(),
    152       constructor->GetHeap()->ReinitializeJSGlobalProxy(*constructor, *global),
    153       JSGlobalProxy);
    154 }
    155 
    156 
    157 void SetExpectedNofProperties(Handle<JSFunction> func, int nof) {
    158   // If objects constructed from this function exist then changing
    159   // 'estimated_nof_properties' is dangerous since the previous value might
    160   // have been compiled into the fast construct stub. More over, the inobject
    161   // slack tracking logic might have adjusted the previous value, so even
    162   // passing the same value is risky.
    163   if (func->shared()->live_objects_may_exist()) return;
    164 
    165   func->shared()->set_expected_nof_properties(nof);
    166   if (func->has_initial_map()) {
    167     Handle<Map> new_initial_map =
    168         func->GetIsolate()->factory()->CopyMapDropTransitions(
    169             Handle<Map>(func->initial_map()));
    170     new_initial_map->set_unused_property_fields(nof);
    171     func->set_initial_map(*new_initial_map);
    172   }
    173 }
    174 
    175 
    176 void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value) {
    177   CALL_HEAP_FUNCTION_VOID(func->GetIsolate(),
    178                           func->SetPrototype(*value));
    179 }
    180 
    181 
    182 static int ExpectedNofPropertiesFromEstimate(int estimate) {
    183   // If no properties are added in the constructor, they are more likely
    184   // to be added later.
    185   if (estimate == 0) estimate = 2;
    186 
    187   // We do not shrink objects that go into a snapshot (yet), so we adjust
    188   // the estimate conservatively.
    189   if (Serializer::enabled()) return estimate + 2;
    190 
    191   // Inobject slack tracking will reclaim redundant inobject space later,
    192   // so we can afford to adjust the estimate generously.
    193   return estimate + 8;
    194 }
    195 
    196 
    197 void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
    198                                           int estimate) {
    199   // See the comment in SetExpectedNofProperties.
    200   if (shared->live_objects_may_exist()) return;
    201 
    202   shared->set_expected_nof_properties(
    203       ExpectedNofPropertiesFromEstimate(estimate));
    204 }
    205 
    206 
    207 void NormalizeProperties(Handle<JSObject> object,
    208                          PropertyNormalizationMode mode,
    209                          int expected_additional_properties) {
    210   CALL_HEAP_FUNCTION_VOID(object->GetIsolate(),
    211                           object->NormalizeProperties(
    212                               mode,
    213                               expected_additional_properties));
    214 }
    215 
    216 
    217 void NormalizeElements(Handle<JSObject> object) {
    218   CALL_HEAP_FUNCTION_VOID(object->GetIsolate(),
    219                           object->NormalizeElements());
    220 }
    221 
    222 
    223 void TransformToFastProperties(Handle<JSObject> object,
    224                                int unused_property_fields) {
    225   CALL_HEAP_FUNCTION_VOID(
    226       object->GetIsolate(),
    227       object->TransformToFastProperties(unused_property_fields));
    228 }
    229 
    230 
    231 void NumberDictionarySet(Handle<NumberDictionary> dictionary,
    232                          uint32_t index,
    233                          Handle<Object> value,
    234                          PropertyDetails details) {
    235   CALL_HEAP_FUNCTION_VOID(dictionary->GetIsolate(),
    236                           dictionary->Set(index, *value, details));
    237 }
    238 
    239 
    240 void FlattenString(Handle<String> string) {
    241   CALL_HEAP_FUNCTION_VOID(string->GetIsolate(), string->TryFlatten());
    242 }
    243 
    244 
    245 Handle<String> FlattenGetString(Handle<String> string) {
    246   CALL_HEAP_FUNCTION(string->GetIsolate(), string->TryFlatten(), String);
    247 }
    248 
    249 
    250 Handle<Object> SetPrototype(Handle<JSFunction> function,
    251                             Handle<Object> prototype) {
    252   ASSERT(function->should_have_prototype());
    253   CALL_HEAP_FUNCTION(function->GetIsolate(),
    254                      Accessors::FunctionSetPrototype(*function,
    255                                                      *prototype,
    256                                                      NULL),
    257                      Object);
    258 }
    259 
    260 
    261 Handle<Object> SetProperty(Handle<JSObject> object,
    262                            Handle<String> key,
    263                            Handle<Object> value,
    264                            PropertyAttributes attributes,
    265                            StrictModeFlag strict_mode) {
    266   CALL_HEAP_FUNCTION(object->GetIsolate(),
    267                      object->SetProperty(*key, *value, attributes, strict_mode),
    268                      Object);
    269 }
    270 
    271 
    272 Handle<Object> SetProperty(Handle<Object> object,
    273                            Handle<Object> key,
    274                            Handle<Object> value,
    275                            PropertyAttributes attributes,
    276                            StrictModeFlag strict_mode) {
    277   Isolate* isolate = Isolate::Current();
    278   CALL_HEAP_FUNCTION(
    279       isolate,
    280       Runtime::SetObjectProperty(
    281           isolate, object, key, value, attributes, strict_mode),
    282       Object);
    283 }
    284 
    285 
    286 Handle<Object> ForceSetProperty(Handle<JSObject> object,
    287                                 Handle<Object> key,
    288                                 Handle<Object> value,
    289                                 PropertyAttributes attributes) {
    290   Isolate* isolate = object->GetIsolate();
    291   CALL_HEAP_FUNCTION(
    292       isolate,
    293       Runtime::ForceSetObjectProperty(
    294           isolate, object, key, value, attributes),
    295       Object);
    296 }
    297 
    298 
    299 Handle<Object> SetNormalizedProperty(Handle<JSObject> object,
    300                                      Handle<String> key,
    301                                      Handle<Object> value,
    302                                      PropertyDetails details) {
    303   CALL_HEAP_FUNCTION(object->GetIsolate(),
    304                      object->SetNormalizedProperty(*key, *value, details),
    305                      Object);
    306 }
    307 
    308 
    309 Handle<Object> ForceDeleteProperty(Handle<JSObject> object,
    310                                    Handle<Object> key) {
    311   Isolate* isolate = object->GetIsolate();
    312   CALL_HEAP_FUNCTION(isolate,
    313                      Runtime::ForceDeleteObjectProperty(isolate, object, key),
    314                      Object);
    315 }
    316 
    317 
    318 Handle<Object> SetLocalPropertyIgnoreAttributes(
    319     Handle<JSObject> object,
    320     Handle<String> key,
    321     Handle<Object> value,
    322     PropertyAttributes attributes) {
    323   CALL_HEAP_FUNCTION(
    324     object->GetIsolate(),
    325     object->SetLocalPropertyIgnoreAttributes(*key, *value, attributes),
    326     Object);
    327 }
    328 
    329 
    330 void SetLocalPropertyNoThrow(Handle<JSObject> object,
    331                              Handle<String> key,
    332                              Handle<Object> value,
    333                              PropertyAttributes attributes) {
    334   Isolate* isolate = object->GetIsolate();
    335   ASSERT(!isolate->has_pending_exception());
    336   CHECK(!SetLocalPropertyIgnoreAttributes(
    337         object, key, value, attributes).is_null());
    338   CHECK(!isolate->has_pending_exception());
    339 }
    340 
    341 
    342 Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object,
    343                                           Handle<String> key,
    344                                           Handle<Object> value,
    345                                           PropertyAttributes attributes,
    346                                           StrictModeFlag strict_mode) {
    347   CALL_HEAP_FUNCTION(object->GetIsolate(),
    348                      object->SetPropertyWithInterceptor(*key,
    349                                                         *value,
    350                                                         attributes,
    351                                                         strict_mode),
    352                      Object);
    353 }
    354 
    355 
    356 Handle<Object> GetProperty(Handle<JSObject> obj,
    357                            const char* name) {
    358   Isolate* isolate = obj->GetIsolate();
    359   Handle<String> str = isolate->factory()->LookupAsciiSymbol(name);
    360   CALL_HEAP_FUNCTION(isolate, obj->GetProperty(*str), Object);
    361 }
    362 
    363 
    364 Handle<Object> GetProperty(Handle<Object> obj,
    365                            Handle<Object> key) {
    366   Isolate* isolate = Isolate::Current();
    367   CALL_HEAP_FUNCTION(isolate,
    368                      Runtime::GetObjectProperty(isolate, obj, key), Object);
    369 }
    370 
    371 
    372 Handle<Object> GetProperty(Handle<JSObject> obj,
    373                            Handle<String> name,
    374                            LookupResult* result) {
    375   PropertyAttributes attributes;
    376   Isolate* isolate = Isolate::Current();
    377   CALL_HEAP_FUNCTION(isolate,
    378                      obj->GetProperty(*obj, result, *name, &attributes),
    379                      Object);
    380 }
    381 
    382 
    383 Handle<Object> GetElement(Handle<Object> obj,
    384                           uint32_t index) {
    385   Isolate* isolate = Isolate::Current();
    386   CALL_HEAP_FUNCTION(isolate, Runtime::GetElement(obj, index), Object);
    387 }
    388 
    389 
    390 Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
    391                                           Handle<JSObject> holder,
    392                                           Handle<String> name,
    393                                           PropertyAttributes* attributes) {
    394   Isolate* isolate = receiver->GetIsolate();
    395   CALL_HEAP_FUNCTION(isolate,
    396                      holder->GetPropertyWithInterceptor(*receiver,
    397                                                         *name,
    398                                                         attributes),
    399                      Object);
    400 }
    401 
    402 
    403 Handle<Object> GetPrototype(Handle<Object> obj) {
    404   Handle<Object> result(obj->GetPrototype());
    405   return result;
    406 }
    407 
    408 
    409 Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value) {
    410   const bool skip_hidden_prototypes = false;
    411   CALL_HEAP_FUNCTION(obj->GetIsolate(),
    412                      obj->SetPrototype(*value, skip_hidden_prototypes), Object);
    413 }
    414 
    415 
    416 Handle<Object> PreventExtensions(Handle<JSObject> object) {
    417   CALL_HEAP_FUNCTION(object->GetIsolate(), object->PreventExtensions(), Object);
    418 }
    419 
    420 
    421 Handle<Object> GetHiddenProperties(Handle<JSObject> obj,
    422                                    bool create_if_needed) {
    423   Isolate* isolate = obj->GetIsolate();
    424   Object* holder = obj->BypassGlobalProxy();
    425   if (holder->IsUndefined()) return isolate->factory()->undefined_value();
    426   obj = Handle<JSObject>(JSObject::cast(holder), isolate);
    427 
    428   if (obj->HasFastProperties()) {
    429     // If the object has fast properties, check whether the first slot
    430     // in the descriptor array matches the hidden symbol. Since the
    431     // hidden symbols hash code is zero (and no other string has hash
    432     // code zero) it will always occupy the first entry if present.
    433     DescriptorArray* descriptors = obj->map()->instance_descriptors();
    434     if ((descriptors->number_of_descriptors() > 0) &&
    435         (descriptors->GetKey(0) == isolate->heap()->hidden_symbol()) &&
    436         descriptors->IsProperty(0)) {
    437       ASSERT(descriptors->GetType(0) == FIELD);
    438       return Handle<Object>(obj->FastPropertyAt(descriptors->GetFieldIndex(0)),
    439                             isolate);
    440     }
    441   }
    442 
    443   // Only attempt to find the hidden properties in the local object and not
    444   // in the prototype chain.  Note that HasLocalProperty() can cause a GC in
    445   // the general case in the presence of interceptors.
    446   if (!obj->HasHiddenPropertiesObject()) {
    447     // Hidden properties object not found. Allocate a new hidden properties
    448     // object if requested. Otherwise return the undefined value.
    449     if (create_if_needed) {
    450       Handle<Object> hidden_obj =
    451           isolate->factory()->NewJSObject(isolate->object_function());
    452       CALL_HEAP_FUNCTION(isolate,
    453                          obj->SetHiddenPropertiesObject(*hidden_obj), Object);
    454     } else {
    455       return isolate->factory()->undefined_value();
    456     }
    457   }
    458   return Handle<Object>(obj->GetHiddenPropertiesObject(), isolate);
    459 }
    460 
    461 
    462 Handle<Object> DeleteElement(Handle<JSObject> obj,
    463                              uint32_t index) {
    464   CALL_HEAP_FUNCTION(obj->GetIsolate(),
    465                      obj->DeleteElement(index, JSObject::NORMAL_DELETION),
    466                      Object);
    467 }
    468 
    469 
    470 Handle<Object> DeleteProperty(Handle<JSObject> obj,
    471                               Handle<String> prop) {
    472   CALL_HEAP_FUNCTION(obj->GetIsolate(),
    473                      obj->DeleteProperty(*prop, JSObject::NORMAL_DELETION),
    474                      Object);
    475 }
    476 
    477 
    478 Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index) {
    479   Isolate* isolate = Isolate::Current();
    480   CALL_HEAP_FUNCTION(
    481       isolate,
    482       isolate->heap()->LookupSingleCharacterStringFromCode(index), Object);
    483 }
    484 
    485 
    486 Handle<String> SubString(Handle<String> str,
    487                          int start,
    488                          int end,
    489                          PretenureFlag pretenure) {
    490   CALL_HEAP_FUNCTION(str->GetIsolate(),
    491                      str->SubString(start, end, pretenure), String);
    492 }
    493 
    494 
    495 Handle<Object> SetElement(Handle<JSObject> object,
    496                           uint32_t index,
    497                           Handle<Object> value,
    498                           StrictModeFlag strict_mode) {
    499   if (object->HasExternalArrayElements()) {
    500     if (!value->IsSmi() && !value->IsHeapNumber() && !value->IsUndefined()) {
    501       bool has_exception;
    502       Handle<Object> number = Execution::ToNumber(value, &has_exception);
    503       if (has_exception) return Handle<Object>();
    504       value = number;
    505     }
    506   }
    507   CALL_HEAP_FUNCTION(object->GetIsolate(),
    508                      object->SetElement(index, *value, strict_mode), Object);
    509 }
    510 
    511 
    512 Handle<Object> SetOwnElement(Handle<JSObject> object,
    513                              uint32_t index,
    514                              Handle<Object> value,
    515                              StrictModeFlag strict_mode) {
    516   ASSERT(!object->HasExternalArrayElements());
    517   CALL_HEAP_FUNCTION(object->GetIsolate(),
    518                      object->SetElement(index, *value, strict_mode, false),
    519                      Object);
    520 }
    521 
    522 
    523 Handle<JSObject> Copy(Handle<JSObject> obj) {
    524   Isolate* isolate = obj->GetIsolate();
    525   CALL_HEAP_FUNCTION(isolate,
    526                      isolate->heap()->CopyJSObject(*obj), JSObject);
    527 }
    528 
    529 
    530 Handle<Object> SetAccessor(Handle<JSObject> obj, Handle<AccessorInfo> info) {
    531   CALL_HEAP_FUNCTION(obj->GetIsolate(), obj->DefineAccessor(*info), Object);
    532 }
    533 
    534 
    535 // Wrappers for scripts are kept alive and cached in weak global
    536 // handles referred from proxy objects held by the scripts as long as
    537 // they are used. When they are not used anymore, the garbage
    538 // collector will call the weak callback on the global handle
    539 // associated with the wrapper and get rid of both the wrapper and the
    540 // handle.
    541 static void ClearWrapperCache(Persistent<v8::Value> handle, void*) {
    542 #ifdef ENABLE_HEAP_PROTECTION
    543   // Weak reference callbacks are called as if from outside V8.  We
    544   // need to reeenter to unprotect the heap.
    545   VMState state(OTHER);
    546 #endif
    547   Handle<Object> cache = Utils::OpenHandle(*handle);
    548   JSValue* wrapper = JSValue::cast(*cache);
    549   Proxy* proxy = Script::cast(wrapper->value())->wrapper();
    550   ASSERT(proxy->proxy() == reinterpret_cast<Address>(cache.location()));
    551   proxy->set_proxy(0);
    552   Isolate* isolate = Isolate::Current();
    553   isolate->global_handles()->Destroy(cache.location());
    554   isolate->counters()->script_wrappers()->Decrement();
    555 }
    556 
    557 
    558 Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
    559   if (script->wrapper()->proxy() != NULL) {
    560     // Return the script wrapper directly from the cache.
    561     return Handle<JSValue>(
    562         reinterpret_cast<JSValue**>(script->wrapper()->proxy()));
    563   }
    564   Isolate* isolate = Isolate::Current();
    565   // Construct a new script wrapper.
    566   isolate->counters()->script_wrappers()->Increment();
    567   Handle<JSFunction> constructor = isolate->script_function();
    568   Handle<JSValue> result =
    569       Handle<JSValue>::cast(isolate->factory()->NewJSObject(constructor));
    570   result->set_value(*script);
    571 
    572   // Create a new weak global handle and use it to cache the wrapper
    573   // for future use. The cache will automatically be cleared by the
    574   // garbage collector when it is not used anymore.
    575   Handle<Object> handle = isolate->global_handles()->Create(*result);
    576   isolate->global_handles()->MakeWeak(handle.location(), NULL,
    577                                       &ClearWrapperCache);
    578   script->wrapper()->set_proxy(reinterpret_cast<Address>(handle.location()));
    579   return result;
    580 }
    581 
    582 
    583 // Init line_ends array with code positions of line ends inside script
    584 // source.
    585 void InitScriptLineEnds(Handle<Script> script) {
    586   if (!script->line_ends()->IsUndefined()) return;
    587 
    588   Isolate* isolate = script->GetIsolate();
    589 
    590   if (!script->source()->IsString()) {
    591     ASSERT(script->source()->IsUndefined());
    592     Handle<FixedArray> empty = isolate->factory()->NewFixedArray(0);
    593     script->set_line_ends(*empty);
    594     ASSERT(script->line_ends()->IsFixedArray());
    595     return;
    596   }
    597 
    598   Handle<String> src(String::cast(script->source()), isolate);
    599 
    600   Handle<FixedArray> array = CalculateLineEnds(src, true);
    601 
    602   if (*array != isolate->heap()->empty_fixed_array()) {
    603     array->set_map(isolate->heap()->fixed_cow_array_map());
    604   }
    605 
    606   script->set_line_ends(*array);
    607   ASSERT(script->line_ends()->IsFixedArray());
    608 }
    609 
    610 
    611 template <typename SourceChar>
    612 static void CalculateLineEnds(Isolate* isolate,
    613                               List<int>* line_ends,
    614                               Vector<const SourceChar> src,
    615                               bool with_last_line) {
    616   const int src_len = src.length();
    617   StringSearch<char, SourceChar> search(isolate, CStrVector("\n"));
    618 
    619   // Find and record line ends.
    620   int position = 0;
    621   while (position != -1 && position < src_len) {
    622     position = search.Search(src, position);
    623     if (position != -1) {
    624       line_ends->Add(position);
    625       position++;
    626     } else if (with_last_line) {
    627       // Even if the last line misses a line end, it is counted.
    628       line_ends->Add(src_len);
    629       return;
    630     }
    631   }
    632 }
    633 
    634 
    635 Handle<FixedArray> CalculateLineEnds(Handle<String> src,
    636                                      bool with_last_line) {
    637   src = FlattenGetString(src);
    638   // Rough estimate of line count based on a roughly estimated average
    639   // length of (unpacked) code.
    640   int line_count_estimate = src->length() >> 4;
    641   List<int> line_ends(line_count_estimate);
    642   Isolate* isolate = src->GetIsolate();
    643   {
    644     AssertNoAllocation no_heap_allocation;  // ensure vectors stay valid.
    645     // Dispatch on type of strings.
    646     if (src->IsAsciiRepresentation()) {
    647       CalculateLineEnds(isolate,
    648                         &line_ends,
    649                         src->ToAsciiVector(),
    650                         with_last_line);
    651     } else {
    652       CalculateLineEnds(isolate,
    653                         &line_ends,
    654                         src->ToUC16Vector(),
    655                         with_last_line);
    656     }
    657   }
    658   int line_count = line_ends.length();
    659   Handle<FixedArray> array = isolate->factory()->NewFixedArray(line_count);
    660   for (int i = 0; i < line_count; i++) {
    661     array->set(i, Smi::FromInt(line_ends[i]));
    662   }
    663   return array;
    664 }
    665 
    666 
    667 // Convert code position into line number.
    668 int GetScriptLineNumber(Handle<Script> script, int code_pos) {
    669   InitScriptLineEnds(script);
    670   AssertNoAllocation no_allocation;
    671   FixedArray* line_ends_array = FixedArray::cast(script->line_ends());
    672   const int line_ends_len = line_ends_array->length();
    673 
    674   if (!line_ends_len) return -1;
    675 
    676   if ((Smi::cast(line_ends_array->get(0)))->value() >= code_pos) {
    677     return script->line_offset()->value();
    678   }
    679 
    680   int left = 0;
    681   int right = line_ends_len;
    682   while (int half = (right - left) / 2) {
    683     if ((Smi::cast(line_ends_array->get(left + half)))->value() > code_pos) {
    684       right -= half;
    685     } else {
    686       left += half;
    687     }
    688   }
    689   return right + script->line_offset()->value();
    690 }
    691 
    692 
    693 int GetScriptLineNumberSafe(Handle<Script> script, int code_pos) {
    694   AssertNoAllocation no_allocation;
    695   if (!script->line_ends()->IsUndefined()) {
    696     return GetScriptLineNumber(script, code_pos);
    697   }
    698   // Slow mode: we do not have line_ends. We have to iterate through source.
    699   if (!script->source()->IsString()) {
    700     return -1;
    701   }
    702   String* source = String::cast(script->source());
    703   int line = 0;
    704   int len = source->length();
    705   for (int pos = 0; pos < len; pos++) {
    706     if (pos == code_pos) {
    707       break;
    708     }
    709     if (source->Get(pos) == '\n') {
    710       line++;
    711     }
    712   }
    713   return line;
    714 }
    715 
    716 
    717 void CustomArguments::IterateInstance(ObjectVisitor* v) {
    718   v->VisitPointers(values_, values_ + ARRAY_SIZE(values_));
    719 }
    720 
    721 
    722 // Compute the property keys from the interceptor.
    723 v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver,
    724                                                  Handle<JSObject> object) {
    725   Isolate* isolate = receiver->GetIsolate();
    726   Handle<InterceptorInfo> interceptor(object->GetNamedInterceptor());
    727   CustomArguments args(isolate, interceptor->data(), *receiver, *object);
    728   v8::AccessorInfo info(args.end());
    729   v8::Handle<v8::Array> result;
    730   if (!interceptor->enumerator()->IsUndefined()) {
    731     v8::NamedPropertyEnumerator enum_fun =
    732         v8::ToCData<v8::NamedPropertyEnumerator>(interceptor->enumerator());
    733     LOG(isolate, ApiObjectAccess("interceptor-named-enum", *object));
    734     {
    735       // Leaving JavaScript.
    736       VMState state(isolate, EXTERNAL);
    737       result = enum_fun(info);
    738     }
    739   }
    740   return result;
    741 }
    742 
    743 
    744 // Compute the element keys from the interceptor.
    745 v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSObject> receiver,
    746                                                    Handle<JSObject> object) {
    747   Isolate* isolate = receiver->GetIsolate();
    748   Handle<InterceptorInfo> interceptor(object->GetIndexedInterceptor());
    749   CustomArguments args(isolate, interceptor->data(), *receiver, *object);
    750   v8::AccessorInfo info(args.end());
    751   v8::Handle<v8::Array> result;
    752   if (!interceptor->enumerator()->IsUndefined()) {
    753     v8::IndexedPropertyEnumerator enum_fun =
    754         v8::ToCData<v8::IndexedPropertyEnumerator>(interceptor->enumerator());
    755     LOG(isolate, ApiObjectAccess("interceptor-indexed-enum", *object));
    756     {
    757       // Leaving JavaScript.
    758       VMState state(isolate, EXTERNAL);
    759       result = enum_fun(info);
    760     }
    761   }
    762   return result;
    763 }
    764 
    765 
    766 static bool ContainsOnlyValidKeys(Handle<FixedArray> array) {
    767   int len = array->length();
    768   for (int i = 0; i < len; i++) {
    769     Object* e = array->get(i);
    770     if (!(e->IsString() || e->IsNumber())) return false;
    771   }
    772   return true;
    773 }
    774 
    775 
    776 Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSObject> object,
    777                                           KeyCollectionType type) {
    778   USE(ContainsOnlyValidKeys);
    779   Isolate* isolate = object->GetIsolate();
    780   Handle<FixedArray> content = isolate->factory()->empty_fixed_array();
    781   Handle<JSObject> arguments_boilerplate = Handle<JSObject>(
    782       isolate->context()->global_context()->arguments_boilerplate(),
    783       isolate);
    784   Handle<JSFunction> arguments_function = Handle<JSFunction>(
    785       JSFunction::cast(arguments_boilerplate->map()->constructor()),
    786       isolate);
    787 
    788   // Only collect keys if access is permitted.
    789   for (Handle<Object> p = object;
    790        *p != isolate->heap()->null_value();
    791        p = Handle<Object>(p->GetPrototype(), isolate)) {
    792     Handle<JSObject> current(JSObject::cast(*p), isolate);
    793 
    794     // Check access rights if required.
    795     if (current->IsAccessCheckNeeded() &&
    796         !isolate->MayNamedAccess(*current,
    797                                  isolate->heap()->undefined_value(),
    798                                  v8::ACCESS_KEYS)) {
    799       isolate->ReportFailedAccessCheck(*current, v8::ACCESS_KEYS);
    800       break;
    801     }
    802 
    803     // Compute the element keys.
    804     Handle<FixedArray> element_keys =
    805         isolate->factory()->NewFixedArray(current->NumberOfEnumElements());
    806     current->GetEnumElementKeys(*element_keys);
    807     content = UnionOfKeys(content, element_keys);
    808     ASSERT(ContainsOnlyValidKeys(content));
    809 
    810     // Add the element keys from the interceptor.
    811     if (current->HasIndexedInterceptor()) {
    812       v8::Handle<v8::Array> result =
    813           GetKeysForIndexedInterceptor(object, current);
    814       if (!result.IsEmpty())
    815         content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
    816       ASSERT(ContainsOnlyValidKeys(content));
    817     }
    818 
    819     // We can cache the computed property keys if access checks are
    820     // not needed and no interceptors are involved.
    821     //
    822     // We do not use the cache if the object has elements and
    823     // therefore it does not make sense to cache the property names
    824     // for arguments objects.  Arguments objects will always have
    825     // elements.
    826     // Wrapped strings have elements, but don't have an elements
    827     // array or dictionary.  So the fast inline test for whether to
    828     // use the cache says yes, so we should not create a cache.
    829     bool cache_enum_keys =
    830         ((current->map()->constructor() != *arguments_function) &&
    831          !current->IsJSValue() &&
    832          !current->IsAccessCheckNeeded() &&
    833          !current->HasNamedInterceptor() &&
    834          !current->HasIndexedInterceptor());
    835     // Compute the property keys and cache them if possible.
    836     content =
    837         UnionOfKeys(content, GetEnumPropertyKeys(current, cache_enum_keys));
    838     ASSERT(ContainsOnlyValidKeys(content));
    839 
    840     // Add the property keys from the interceptor.
    841     if (current->HasNamedInterceptor()) {
    842       v8::Handle<v8::Array> result =
    843           GetKeysForNamedInterceptor(object, current);
    844       if (!result.IsEmpty())
    845         content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
    846       ASSERT(ContainsOnlyValidKeys(content));
    847     }
    848 
    849     // If we only want local properties we bail out after the first
    850     // iteration.
    851     if (type == LOCAL_ONLY)
    852       break;
    853   }
    854   return content;
    855 }
    856 
    857 
    858 Handle<JSArray> GetKeysFor(Handle<JSObject> object) {
    859   Isolate* isolate = object->GetIsolate();
    860   isolate->counters()->for_in()->Increment();
    861   Handle<FixedArray> elements = GetKeysInFixedArrayFor(object,
    862                                                        INCLUDE_PROTOS);
    863   return isolate->factory()->NewJSArrayWithElements(elements);
    864 }
    865 
    866 
    867 Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
    868                                        bool cache_result) {
    869   int index = 0;
    870   Isolate* isolate = object->GetIsolate();
    871   if (object->HasFastProperties()) {
    872     if (object->map()->instance_descriptors()->HasEnumCache()) {
    873       isolate->counters()->enum_cache_hits()->Increment();
    874       DescriptorArray* desc = object->map()->instance_descriptors();
    875       return Handle<FixedArray>(FixedArray::cast(desc->GetEnumCache()),
    876                                 isolate);
    877     }
    878     isolate->counters()->enum_cache_misses()->Increment();
    879     int num_enum = object->NumberOfEnumProperties();
    880     Handle<FixedArray> storage = isolate->factory()->NewFixedArray(num_enum);
    881     Handle<FixedArray> sort_array = isolate->factory()->NewFixedArray(num_enum);
    882     Handle<DescriptorArray> descs =
    883         Handle<DescriptorArray>(object->map()->instance_descriptors(), isolate);
    884     for (int i = 0; i < descs->number_of_descriptors(); i++) {
    885       if (descs->IsProperty(i) && !descs->IsDontEnum(i)) {
    886         (*storage)->set(index, descs->GetKey(i));
    887         PropertyDetails details(descs->GetDetails(i));
    888         (*sort_array)->set(index, Smi::FromInt(details.index()));
    889         index++;
    890       }
    891     }
    892     (*storage)->SortPairs(*sort_array, sort_array->length());
    893     if (cache_result) {
    894       Handle<FixedArray> bridge_storage =
    895           isolate->factory()->NewFixedArray(
    896               DescriptorArray::kEnumCacheBridgeLength);
    897       DescriptorArray* desc = object->map()->instance_descriptors();
    898       desc->SetEnumCache(*bridge_storage, *storage);
    899     }
    900     ASSERT(storage->length() == index);
    901     return storage;
    902   } else {
    903     int num_enum = object->NumberOfEnumProperties();
    904     Handle<FixedArray> storage = isolate->factory()->NewFixedArray(num_enum);
    905     Handle<FixedArray> sort_array = isolate->factory()->NewFixedArray(num_enum);
    906     object->property_dictionary()->CopyEnumKeysTo(*storage, *sort_array);
    907     return storage;
    908   }
    909 }
    910 
    911 
    912 bool EnsureCompiled(Handle<SharedFunctionInfo> shared,
    913                     ClearExceptionFlag flag) {
    914   return shared->is_compiled() || CompileLazyShared(shared, flag);
    915 }
    916 
    917 
    918 static bool CompileLazyHelper(CompilationInfo* info,
    919                               ClearExceptionFlag flag) {
    920   // Compile the source information to a code object.
    921   ASSERT(info->IsOptimizing() || !info->shared_info()->is_compiled());
    922   ASSERT(!info->isolate()->has_pending_exception());
    923   bool result = Compiler::CompileLazy(info);
    924   ASSERT(result != Isolate::Current()->has_pending_exception());
    925   if (!result && flag == CLEAR_EXCEPTION) {
    926     info->isolate()->clear_pending_exception();
    927   }
    928   return result;
    929 }
    930 
    931 
    932 bool CompileLazyShared(Handle<SharedFunctionInfo> shared,
    933                        ClearExceptionFlag flag) {
    934   CompilationInfo info(shared);
    935   return CompileLazyHelper(&info, flag);
    936 }
    937 
    938 
    939 static bool CompileLazyFunction(Handle<JSFunction> function,
    940                                 ClearExceptionFlag flag,
    941                                 InLoopFlag in_loop_flag) {
    942   bool result = true;
    943   if (function->shared()->is_compiled()) {
    944     function->ReplaceCode(function->shared()->code());
    945     function->shared()->set_code_age(0);
    946   } else {
    947     CompilationInfo info(function);
    948     if (in_loop_flag == IN_LOOP) info.MarkAsInLoop();
    949     result = CompileLazyHelper(&info, flag);
    950     ASSERT(!result || function->is_compiled());
    951   }
    952   return result;
    953 }
    954 
    955 
    956 bool CompileLazy(Handle<JSFunction> function,
    957                  ClearExceptionFlag flag) {
    958   return CompileLazyFunction(function, flag, NOT_IN_LOOP);
    959 }
    960 
    961 
    962 bool CompileLazyInLoop(Handle<JSFunction> function,
    963                        ClearExceptionFlag flag) {
    964   return CompileLazyFunction(function, flag, IN_LOOP);
    965 }
    966 
    967 
    968 bool CompileOptimized(Handle<JSFunction> function,
    969                       int osr_ast_id,
    970                       ClearExceptionFlag flag) {
    971   CompilationInfo info(function);
    972   info.SetOptimizing(osr_ast_id);
    973   return CompileLazyHelper(&info, flag);
    974 }
    975 
    976 } }  // namespace v8::internal
    977