For-of calls [Symbol.iterator]() on RHS to get iterator

src/contexts.h

 // Copyright 2012 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.
 
 #ifndef V8_CONTEXTS_H_
 #define V8_CONTEXTS_H_
 
 #include "src/heap.h"
 #include "src/objects.h"
 
@@ skipping 168 matching lines @@
   V(NATIVE_OBJECT_GET_NOTIFIER_INDEX, JSFunction, \
     native_object_get_notifier) \
   V(NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, JSFunction, \
     native_object_notifier_perform_change) \
   V(SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, Map, sloppy_generator_function_map) \
   V(STRICT_GENERATOR_FUNCTION_MAP_INDEX, Map, strict_generator_function_map) \
   V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, \
     generator_object_prototype_map) \
   V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map) \
   V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map) \
-  V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map)
+  V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map) \
+  V(ITERATOR_SYMBOL_INDEX, Symbol, iterator_symbol)
 
 // JSFunctions are pairs (context, function code), sometimes also called
 // closures. A Context object is used to represent function contexts and
 // dynamically pushed 'with' contexts (or 'scopes' in ECMA-262 speak).
 //
 // At runtime, the contexts build a stack in parallel to the execution
 // stack, with the top-most context being the current context. All contexts
 // have the following slots:
 //
 // [ closure   ]  This is the current function. It is the same for all
@@ skipping 151 matching lines @@
     OBSERVERS_END_SPLICE_INDEX,
     NATIVE_OBJECT_OBSERVE_INDEX,
     NATIVE_OBJECT_GET_NOTIFIER_INDEX,
     NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE,
     SLOPPY_GENERATOR_FUNCTION_MAP_INDEX,
     STRICT_GENERATOR_FUNCTION_MAP_INDEX,
     GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX,
     ITERATOR_RESULT_MAP_INDEX,
     MAP_ITERATOR_MAP_INDEX,
     SET_ITERATOR_MAP_INDEX,
+    ITERATOR_SYMBOL_INDEX,
 
     // Properties from here are treated as weak references by the full GC.
     // Scavenge treats them as strong references.
     OPTIMIZED_FUNCTIONS_LIST,  // Weak.
     OPTIMIZED_CODE_LIST,       // Weak.
     DEOPTIMIZED_CODE_LIST,     // Weak.
     MAP_CACHE_INDEX,           // Weak.
     NEXT_CONTEXT_LINK,         // Weak.
 
     // Total number of slots.
@@ skipping 174 matching lines @@
   static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
 #endif
 
   STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONTEXTS_H_