Wrong Dwarf info with -O2? [PowerPC]

Hi all,

today I was debugging some code (compiled by a 2 weeks old clang) on a
PowerPC embedded system using the newest gdb (v7.4).

I got a backtrace like this:

(gdb) bt
#0 0x0fe96314 in poll () from /lib/tls/libc.so.6
#1 0x1002c8ac in mli_poll (
    fds=<error reading variable: Unhandled dwarf expression opcode 0x1>,
    nfds=<optimized out>, timeout=<optimized out>) at msglib.c:7560
#2 0x10027684 in mli_do_work (peer_index=<optimized out>,
    creply=<error reading variable: Unhandled dwarf expression opcode 0xff>,
    flags=<optimized out>) at msglib.c:6323
#3 0x1002cce8 in ml_wait_for_next_event () at msglib.c:6821
#4 0x1000fdd0 in sys_mainloop () at config.c:1221
#5 0x1000bda8 in main (argc=<optimized out>, argv=<optimized out>)
    at sysmon.c:437

Please note the "Unhandled dwarf expression" errors. Is this a known
problem? How can I help debugging this? Btw., this is dead-simple C
code.

Thanks for any hints,

     Gabor

Please add what you have to:

http://llvm.org/bugs/show_bug.cgi?id=12733

Joerg

Yes please. I could use a testcase that's a little easier to look at than an optimized clang :slight_smile:

(Not that Joerg's repro instructions aren't nice mind you...)

-eric