[es6] JSObject::GetOwnElementKeys should collect String wrapper keys first

src/objects.cc

 // Copyright 2013 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 <iomanip>
 #include <sstream>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
@@ skipping 12954 matching lines @@
     if (length == 0) return 0;
   }
   // Compute the number of enumerable elements.
   return NumberOfOwnElements(static_cast<PropertyAttributes>(DONT_ENUM));
 }
 
 
 int JSObject::GetOwnElementKeys(FixedArray* storage,
                                 PropertyAttributes filter) {
   int counter = 0;
+
+  // If this is a String wrapper, add the string indices first,
+  // as they're guaranteed to preced the elements in numerical order
+  // and ascending order is required by ECMA-262, 6th, 9.1.12.
+  if (IsJSValue()) {
+    Object* val = JSValue::cast(this)->value();
+    if (val->IsString()) {
+      String* str = String::cast(val);
+      if (storage) {
+        for (int i = 0; i < str->length(); i++) {
+          storage->set(counter + i, Smi::FromInt(i));
+        }
+      }
+      counter += str->length();
+    }
+  }
+
   switch (GetElementsKind()) {
     case FAST_SMI_ELEMENTS:
     case FAST_ELEMENTS:
     case FAST_HOLEY_SMI_ELEMENTS:
     case FAST_HOLEY_ELEMENTS: {
       int length = IsJSArray() ?
           Smi::cast(JSArray::cast(this)->length())->value() :
           FixedArray::cast(elements())->length();
       for (int i = 0; i < length; i++) {
         if (!FixedArray::cast(elements())->get(i)->IsTheHole()) {
@@ skipping 86 matching lines @@
         }
         for (; i < backing_length; ++i) {
           if (storage != NULL) storage->set(counter, Smi::FromInt(i));
           ++counter;
         }
       }
       break;
     }
   }
 
-  if (this->IsJSValue()) {
-    Object* val = JSValue::cast(this)->value();
-    if (val->IsString()) {
-      String* str = String::cast(val);
-      if (storage) {
-        for (int i = 0; i < str->length(); i++) {
-          storage->set(counter + i, Smi::FromInt(i));
-        }
-      }
-      counter += str->length();
-    }
-  }
   DCHECK(!storage || storage->length() == counter);
   return counter;
 }
 
 
 int JSObject::GetEnumElementKeys(FixedArray* storage) {
   return GetOwnElementKeys(storage, static_cast<PropertyAttributes>(DONT_ENUM));
 }
 
 
@@ skipping 2827 matching lines @@
                                             Handle<Object> new_value) {
   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