* fix empty_var_name problem

* fix coverage ci

* fix coverage ci

* fix

* fix

* fix

* fix

* fix

* fix coverage ci

* add test case

* refine program translator

* fix warning: not override

* fix bug

* merge new modifications

* modify by reviews

* resolve conflicts

* resolve conflicts

* fix

* fix

* fix conflicts

* add unittest for special op transcriber

* set cpu as default backend

* modify by reviews