You can use UPDATE with JOIN to do this.
Check something like following-
UPDATE S SET S.salary=S.salary+(S.salary*(CASE WHEN R.[role]='a' THEN 0.2 WHEN R.[role]='c' THEN 0.3 ELSE 0 END))
FROM sal S
INNER JOIN map M ON S.empid=M.empid
INNER JOIN rolemaster R ON R.roleid=M.roleid
I have't executed it so minor changes may be required. Please let me know in case it doesn't help.
Thanks