[Arguments] Introduce a new backing store for non-strict arguments objects.

src/objects-inl.h

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 596 matching lines @@
 
 
 bool Object::IsHashTable() {
   return Object::IsHeapObject() &&
       HeapObject::cast(this)->map() ==
       HeapObject::cast(this)->GetHeap()->hash_table_map();
 }
 
 
 bool Object::IsDictionary() {
-  return IsHashTable() && this !=
-         HeapObject::cast(this)->GetHeap()->symbol_table();
+  return IsHashTable() &&
+      this != HeapObject::cast(this)->GetHeap()->symbol_table();
 }
 
 
 bool Object::IsSymbolTable() {
   return IsHashTable() && this ==
          HeapObject::cast(this)->GetHeap()->raw_unchecked_symbol_table();
 }
 
 
 bool Object::IsJSFunctionResultCache() {
@@ skipping 2925 matching lines @@
 
 
 JSObject::ElementsKind JSObject::GetElementsKind() {
   if (map()->has_fast_elements()) {
     ASSERT(elements()->map() == GetHeap()->fixed_array_map() ||
            elements()->map() == GetHeap()->fixed_cow_array_map());
     return FAST_ELEMENTS;
   }
   HeapObject* array = elements();
   if (array->IsFixedArray()) {
-    // FAST_ELEMENTS or DICTIONARY_ELEMENTS are both stored in a
-    // FixedArray, but FAST_ELEMENTS is already handled above.
+    // FAST_ELEMENTS, DICTIONARY_ELEMENTS, and NON_STRICT_ARGUMENTS_ELEMENTS
+    // are all stored in a FixedArray, but FAST_ELEMENTS is already handled
+    // above.
+    if (array->map() == GetHeap()->non_strict_arguments_elements()) {
+      return NON_STRICT_ARGUMENTS_ELEMENTS;
+    }
     ASSERT(array->IsDictionary());
     return DICTIONARY_ELEMENTS;
   }
-  ASSERT(!map()->has_fast_elements());
-  if (array->IsExternalArray()) {
-    switch (array->map()->instance_type()) {
-      case EXTERNAL_BYTE_ARRAY_TYPE:
-        return EXTERNAL_BYTE_ELEMENTS;
-      case EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE:
-        return EXTERNAL_UNSIGNED_BYTE_ELEMENTS;
-      case EXTERNAL_SHORT_ARRAY_TYPE:
-        return EXTERNAL_SHORT_ELEMENTS;
-      case EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE:
-        return EXTERNAL_UNSIGNED_SHORT_ELEMENTS;
-      case EXTERNAL_INT_ARRAY_TYPE:
-        return EXTERNAL_INT_ELEMENTS;
-      case EXTERNAL_UNSIGNED_INT_ARRAY_TYPE:
-        return EXTERNAL_UNSIGNED_INT_ELEMENTS;
-      case EXTERNAL_PIXEL_ARRAY_TYPE:
-        return EXTERNAL_PIXEL_ELEMENTS;
-      default:
-        break;
-    }
+  ASSERT(array->IsExternalArray());
+  switch (array->map()->instance_type()) {
+    case EXTERNAL_BYTE_ARRAY_TYPE:
+      return EXTERNAL_BYTE_ELEMENTS;
+    case EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE:
+      return EXTERNAL_UNSIGNED_BYTE_ELEMENTS;
+    case EXTERNAL_SHORT_ARRAY_TYPE:
+      return EXTERNAL_SHORT_ELEMENTS;
+    case EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE:
+      return EXTERNAL_UNSIGNED_SHORT_ELEMENTS;
+    case EXTERNAL_INT_ARRAY_TYPE:
+      return EXTERNAL_INT_ELEMENTS;
+    case EXTERNAL_UNSIGNED_INT_ARRAY_TYPE:
+      return EXTERNAL_UNSIGNED_INT_ELEMENTS;
+    case EXTERNAL_PIXEL_ARRAY_TYPE:
+      return EXTERNAL_PIXEL_ELEMENTS;
   }
   ASSERT(array->map()->instance_type() == EXTERNAL_FLOAT_ARRAY_TYPE);
   return EXTERNAL_FLOAT_ELEMENTS;
 }
 
 
 bool JSObject::HasFastElements() {
   return GetElementsKind() == FAST_ELEMENTS;
 }
 
@@ skipping 492 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_