First take on custom call generators.

src/log.cc

 // Copyright 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 1328 matching lines @@
                               *script_name, line_num + 1));
         } else {
           // Can't distinguish enum and script here, so always use Script.
           LOG(CodeCreateEvent(Logger::SCRIPT_TAG,
                               shared->code(), *script_name));
         }
       } else {
         LOG(CodeCreateEvent(
             Logger::LAZY_COMPILE_TAG, shared->code(), *func_name));
       }
-    } else if (shared->function_data()->IsFunctionTemplateInfo()) {
+    } else if (shared->IsApiFunction()) {
       // API function.
-      FunctionTemplateInfo* fun_data =
-          FunctionTemplateInfo::cast(shared->function_data());
+      FunctionTemplateInfo* fun_data = shared->get_api_func_data();
       Object* raw_call_data = fun_data->call_code();
       if (!raw_call_data->IsUndefined()) {
         CallHandlerInfo* call_data = CallHandlerInfo::cast(raw_call_data);
         Object* callback_obj = call_data->callback();
         Address entry_point = v8::ToCData<Address>(callback_obj);
         LOG(CallbackEvent(*func_name, entry_point));
       }
     } else {
       LOG(CodeCreateEvent(
           Logger::LAZY_COMPILE_TAG, shared->code(), *func_name));
@@ skipping 191 matching lines @@
   // Otherwise, if the sliding state window computation has not been
   // started we do it now.
   if (sliding_state_window_ == NULL) {
     sliding_state_window_ = new SlidingStateWindow();
   }
 #endif
 }
 
 
 } }  // namespace v8::internal