First take on custom call generators.

src/objects.cc

 // Copyright 2006-2009 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 462 matching lines @@
   }
   return Heap::true_value();
 }
 
 
 bool JSObject::IsDirty() {
   Object* cons_obj = map()->constructor();
   if (!cons_obj->IsJSFunction())
     return true;
   JSFunction* fun = JSFunction::cast(cons_obj);
-  if (!fun->shared()->function_data()->IsFunctionTemplateInfo())
+  if (!fun->shared()->IsApiFunction())
     return true;
   // If the object is fully fast case and has the same map it was
   // created with then no changes can have been made to it.
   return map() != fun->initial_map()
       || !HasFastElements()
       || !HasFastProperties();
 }
 
 
 Object* Object::GetProperty(Object* receiver,
@@ skipping 5932 matching lines @@
       elements->set(pos++, ValueAt(i), mode);
     }
   }
   ASSERT(pos == elements->length());
 }
 
 
 InterceptorInfo* JSObject::GetNamedInterceptor() {
   ASSERT(map()->has_named_interceptor());
   JSFunction* constructor = JSFunction::cast(map()->constructor());
-  Object* template_info = constructor->shared()->function_data();
+  ASSERT(constructor->shared()->IsApiFunction());
   Object* result =
-      FunctionTemplateInfo::cast(template_info)->named_property_handler();
+      constructor->shared()->get_api_func_data()->named_property_handler();
   return InterceptorInfo::cast(result);
 }
 
 
 InterceptorInfo* JSObject::GetIndexedInterceptor() {
   ASSERT(map()->has_indexed_interceptor());
   JSFunction* constructor = JSFunction::cast(map()->constructor());
-  Object* template_info = constructor->shared()->function_data();
+  ASSERT(constructor->shared()->IsApiFunction());
   Object* result =
-      FunctionTemplateInfo::cast(template_info)->indexed_property_handler();
+      constructor->shared()->get_api_func_data()->indexed_property_handler();
   return InterceptorInfo::cast(result);
 }
 
 
 Object* JSObject::GetPropertyPostInterceptor(JSObject* receiver,
                                              String* name,
                                              PropertyAttributes* attributes) {
   // Check local property in holder, ignore interceptor.
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
@@ skipping 2120 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal