arrange to create prototypes for generators

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index fece9a09c91779c6f360d842a7c2b3b9a7a51791..a2e91e64a5acfd3dc90469963aa195411bdc2ee8 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -578,15 +578,31 @@ Handle<JSFunction> Factory::BaseNewFunctionFromSharedFunctionInfo(
 }
 
 
+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()) {
@@ -595,6 +611,16 @@ Handle<JSFunction> Factory::NewFunctionFromSharedFunctionInfo(
 
   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();