Retrieving variable names from ids in pl_exec.c

Hello,

Is there any way to retrieve the actual variable names (as were given
during Stored Procedure definition) for the corresponding var_ids in
pl/plpgsql/src/pl_exec.c ?
I have modified some PostgreSQL code for my own project and I track some
information for functions during their execution. It would be much more
clear at the end if I could map variable ids to their actual names.

Thanks in advance