I can't debug gcc 4.0 with gdb: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19124 When I used idb, I got (idb) stop in tls_symbolic_operand Info: Optimized variables show as <no value> when no location is allocated. [#1: stop in int tls_symbolic_operand(rtx, enum machine_mode)] (idb) r Is that a gdb/readelf or gcc bug? H.J.