Calling a generator function returns a generator object

src/heap.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 4071 matching lines @@
 
 MaybeObject* Heap::AllocateInitialMap(JSFunction* fun) {
   ASSERT(!fun->has_initial_map());
 
   // First create a new map with the size and number of in-object properties
   // suggested by the function.
   InstanceType instance_type;
   int instance_size;
   int in_object_properties;
   if (fun->shared()->is_generator()) {
-    // TODO(wingo): Replace with JS_GENERATOR_OBJECT_TYPE.
-    instance_type = JS_OBJECT_TYPE;
-    instance_size = JSObject::kHeaderSize;
+    instance_type = JS_GENERATOR_OBJECT_TYPE;
+    instance_size = JSGeneratorObject::kSize;
     in_object_properties = 0;
   } else {
     instance_type = JS_OBJECT_TYPE;
     instance_size = fun->shared()->CalculateInstanceSize();
     in_object_properties = fun->shared()->CalculateInObjectProperties();
   }
   Map* map;
   MaybeObject* maybe_map = AllocateMap(instance_type, instance_size);
   if (!maybe_map->To(&map)) return maybe_map;
 
@@ skipping 228 matching lines @@
   }
 #ifdef DEBUG
   // Make sure result is NOT a global object if valid.
   Object* non_failure;
   ASSERT(!result->ToObject(&non_failure) || !non_failure->IsGlobalObject());
 #endif
   return result;
 }
 
 
+MaybeObject* Heap::AllocateJSGeneratorObject(JSFunction *function) {
+  ASSERT(function->shared()->is_generator());
+  // Allocate the initial map if absent.
+  if (!function->has_initial_map()) {
+    Object* initial_map;
+    MaybeObject* maybe_initial_map = AllocateInitialMap(function);
+    if (!maybe_initial_map->ToObject(&initial_map)) return maybe_initial_map;

[Michael Starzinger, 2013/04/11 19:17:39]

Just use "maybe_initial_map->To()" here and make the initial_map a "Map*", this
avoids casting. I know other places do it in this verbose fashion, but those are
left-overs from a script-driven transformation.

[wingo, 2013/04/12 10:50:17]

Done.

+    function->set_initial_map(Map::cast(initial_map));
+  }
+  Map *map = function->initial_map();
+  ASSERT(map->IsMap());

[Michael Starzinger, 2013/04/11 19:17:39]

This assert is obsolete, the accessor should already assert this.

[wingo, 2013/04/12 10:50:17]

Done.

+  ASSERT(map->instance_type() == JS_GENERATOR_OBJECT_TYPE);
+  JSGeneratorObject *generator;
+  MaybeObject* maybe_generator = AllocateJSObjectFromMap(map, NOT_TENURED);

[Michael Starzinger, 2013/04/11 19:17:39]

The NOT_TENURED flag should be the default argument, just skip the argument here
as long this function doesn't support pre-tenuring.

[wingo, 2013/04/12 10:50:17]

Done.

+  if (!maybe_generator->To(&generator)) return maybe_generator;
+  generator->set_function(function);
+  generator->set_context(Smi::FromInt(0));
+  generator->set_continuation(0);
+  generator->set_operand_stack(Smi::FromInt(0));
+  return generator;
+}
+
+
 MaybeObject* Heap::AllocateJSModule(Context* context, ScopeInfo* scope_info) {
   // Allocate a fresh map. Modules do not have a prototype.
   Map* map;
   MaybeObject* maybe_map = AllocateMap(JS_MODULE_TYPE, JSModule::kSize);
   if (!maybe_map->To(&map)) return maybe_map;
   // Allocate the object based on the map.
   JSModule* module;
   MaybeObject* maybe_module = AllocateJSObjectFromMap(map, TENURED);
   if (!maybe_module->To(&module)) return maybe_module;
   module->set_context(context);
@@ skipping 3480 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   memcpy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   memcpy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal