read_def时加上-add_def_only_objects选项可导入netlist中没有的cell等。
status read_def
[-design block]
[-syntax_only]
[-no_incremental]
[-convert_sites conversion_spec]
[-add_def_only_objects all | cells | nets | ports | none]
[-traverse_physical_hierarchy]
file_names
[-include include_list]
[-exclude exclude_list]