arrange to create prototypes for generators

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 560 matching lines @@
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateFunction(*function_map,
                                           *function_info,
                                           isolate()->heap()->the_hole_value(),
                                           pretenure),
                      JSFunction);
 }
 
 
+static Handle<Map> MapForNewFunction(Isolate *isolate,
+                                     Handle<SharedFunctionInfo> function_info) {
+  if (function_info->is_generator()) {
+    if (function_info->is_classic_mode()) {
+      return isolate->generator_function_map();
+    } else {
+      return isolate->strict_mode_generator_function_map();
+    }
+  } else {
+    if (function_info->is_classic_mode()) {
+      return isolate->function_map();
+    } else {
+      return isolate->strict_mode_function_map();
+    }
+  }
+}
+
+
 Handle<JSFunction> Factory::NewFunctionFromSharedFunctionInfo(
     Handle<SharedFunctionInfo> function_info,
     Handle<Context> context,
     PretenureFlag pretenure) {
   Handle<JSFunction> result = BaseNewFunctionFromSharedFunctionInfo(
       function_info,
-      function_info->is_classic_mode()
-          ? isolate()->function_map()
-          : isolate()->strict_mode_function_map(),
+      MapForNewFunction(isolate(), function_info),
       pretenure);
 
   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.

[rossberg, 2013/04/09 16:44:14]

I don't understand. Why can't you make the case distinction in
AllocateFunctionPrototype? Why does it have to be eager?

+    // TODO(wingo): Use JS_GENERATOR_TYPE.
+    Handle<Map> instance_map = NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
+    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) {
       // Store the native context in the literals array prefix. This
       // context will be used when creating object, regexp and array
       // literals in this function.
       literals->set(JSFunction::kLiteralNativeContextIndex,
                     context->native_context());
@@ skipping 871 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal