It is not possible in PLD 'as is'
but
I made the following workaround:
1. Run SQL with unique comment
select /*mycomm*/ * from dual
2. Run XPLAN
select * from table(dbms_xplan.display_cursor(sql_id =>
(select sql_id from v$sql
where upper(sql_text) like '%/*MYCOMM*/%' and upper(sql_text) not like '%/*MYCOMM1*/%'),
format => 'ADVANCED')
)