read_rtlil - read modules from RTLIL file

yosys> help read_rtlil
read_rtlil [filename]
Load modules from an RTLIL file to the current design. (RTLIL is a text
representation of a design in yosys's internal format.)
ignore re-definitions of modules. (the default behavior is to
create an error message if the existing module is not a blackbox
module, and overwrite the existing module if it is a blackbox module.)
overwrite existing modules with the same name
only create empty blackbox modules