[esnext] handle elements in FastObjectValuesOrEntries()

src/objects.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 8734 matching lines @@
 
 MUST_USE_RESULT Maybe<bool> FastGetOwnValuesOrEntries(
     Isolate* isolate, Handle<JSReceiver> receiver, bool get_entries,
     Handle<FixedArray>* result) {
   Handle<Map> map(JSReceiver::cast(*receiver)->map(), isolate);
 
   if (!map->IsJSObjectMap()) return Just(false);
   if (!map->OnlyHasSimpleProperties()) return Just(false);
 
   Handle<JSObject> object(JSObject::cast(*receiver));
-  if (object->elements() != isolate->heap()->empty_fixed_array()) {
-    return Just(false);
-  }
 
   Handle<DescriptorArray> descriptors(map->instance_descriptors(), isolate);
   int number_of_own_descriptors = map->NumberOfOwnDescriptors();
-  Handle<FixedArray> values_or_entries =
-      isolate->factory()->NewFixedArray(number_of_own_descriptors);
+  int number_of_own_elements = object->NumberOfOwnElements(ALL_PROPERTIES);

[Camillo Bruni, 2016/03/16 16:04:02]

This is a fairly costly operation for HOlEY elements.
I had the same issue in PrependElementIndices, so you're probably faster by
using ElementsAccessor::GetCapacity for this (which will be a slight
over-estimation).

[caitp (gmail), 2016/03/17 13:28:40]

Done

+  Handle<FixedArray> values_or_entries = isolate->factory()->NewFixedArray(
+      number_of_own_descriptors + number_of_own_elements);
   int count = 0;
 
-  bool stable = true;
+  if (object->elements() != isolate->heap()->empty_fixed_array()) {
+    MAYBE_RETURN(object->GetElementsAccessor()->CollectValuesOrEntries(
+                     isolate, object, values_or_entries, get_entries, &count,
+                     ENUMERABLE_STRINGS),
+                 Nothing<bool>());
+  }
+
+  bool stable = object->map() == *map;
 
   for (int index = 0; index < number_of_own_descriptors; index++) {
     Handle<Name> next_key(descriptors->GetKey(index), isolate);
     if (!next_key->IsString()) continue;
     Handle<Object> prop_value;
 
     // Directly decode from the descriptor array if |from| did not change shape.
     if (stable) {
       PropertyDetails details = descriptors->GetDetails(index);
       if (!details.IsEnumerable()) continue;
@@ skipping 18 matching lines @@
       LookupIterator it(object, next_key, LookupIterator::OWN_SKIP_INTERCEPTOR);
       if (!it.IsFound()) continue;
       DCHECK(it.state() == LookupIterator::DATA ||
              it.state() == LookupIterator::ACCESSOR);
       if (!it.IsEnumerable()) continue;
       ASSIGN_RETURN_ON_EXCEPTION_VALUE(
           isolate, prop_value, Object::GetProperty(&it), Nothing<bool>());
     }
 
     if (get_entries) {
-      Handle<FixedArray> entry_storage =
-          isolate->factory()->NewUninitializedFixedArray(2);
-      entry_storage->set(0, *next_key);
-      entry_storage->set(1, *prop_value);
-      prop_value = isolate->factory()->NewJSArrayWithElements(entry_storage,
-                                                              FAST_ELEMENTS, 2);
+      prop_value = MakeEntryPair(isolate, next_key, prop_value);
     }
 
     values_or_entries->set(count, *prop_value);
     count++;
   }
 
   if (count < values_or_entries->length()) values_or_entries->Shrink(count);
   *result = values_or_entries;
   return Just(true);
 }
@@ skipping 10947 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8