About the rate_controller_run()

Hi, I’m learning the attitude control of ardupilot copter code and I have some questions.
In archive(http://ardupilot.org/dev/docs/apmcopter-programming-attitude-control-2.html),
it says rate_controller_run() in AC_AttitudeControl.cpp converts the output but instead rate_controller_run() is in AC_AttitudeControl_Multi.cpp and attitude_controller_run_quat() is in AC_AttitudeControl.cpp.
In copter, which one is used to convert and send the output to motor?
Thank you.