Calling a generator function returns a generator object

src/factory.cc

 // Copyright 2012 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 @@
 
   if (function_info->ic_age() != isolate()->heap()->global_ic_age()) {
     function_info->ResetForNewContext(isolate()->heap()->global_ic_age());
   }
 
   result->set_context(*context);
 
   if (function_info->is_generator()) {
     // Generator functions have specialized prototypes and instance types, so
     // they need their prototypes to be created eagerly.
-    // TODO(wingo): Use JS_GENERATOR_TYPE.
-    Handle<Map> instance_map = NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
+    Handle<Map> instance_map =
+      NewMap(JS_GENERATOR_ITERATOR_TYPE, JSGeneratorIterator::kSize);
     Handle<JSObject> iterator_prototype = NewFunctionPrototype(result);
     instance_map->set_prototype(*iterator_prototype);
     result->set_initial_map(*instance_map);
   }
 
   int index = function_info->SearchOptimizedCodeMap(context->native_context());
   if (!function_info->bound() && index < 0) {
     int number_of_literals = function_info->num_literals();
     Handle<FixedArray> literals = NewFixedArray(number_of_literals, pretenure);
     if (number_of_literals > 0) {
@@ skipping 342 matching lines @@
 
 
 Handle<JSObject> Factory::NewJSObject(Handle<JSFunction> constructor,
                                       PretenureFlag pretenure) {
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateJSObject(*constructor, pretenure), JSObject);
 }
 
 
+Handle<JSGeneratorIterator> Factory::NewJSGeneratorIterator(
+    Handle<JSFunction> function) {
+  CALL_HEAP_FUNCTION(
+      isolate(),
+      isolate()->heap()->AllocateJSGeneratorIterator(*function),
+      JSGeneratorIterator);
+}
+
+
 Handle<JSModule> Factory::NewJSModule(Handle<Context> context,
                                       Handle<ScopeInfo> scope_info) {
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateJSModule(*context, *scope_info), JSModule);
 }
 
 
 Handle<GlobalObject> Factory::NewGlobalObject(
     Handle<JSFunction> constructor) {
@@ skipping 514 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal