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..73e3cda02580d7232602d8e0e73840eaa71d7e24 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()) {