frame_register_unwind(): "frame != NULL" assertion failure

[Kevin Buettner <kevinb@redhat.com>]

Andrew,

Any ideas about what to do about this assertion failure?  This is
occurring in a mips-linux native gdb built using current sources. 
(Okay, they're a few hours old by now...) I was debugging gdb with
itself and was running to a breakpoint placed on main().

#0  internal_error (
    file=0x7a1a60 "/home/devel/kevinb/sourceware-mips64/src.baseline/gdb/frame.c", line=187, string=0x7a1aa0 "%s%sAssertion `%s' failed.")
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/utils.c:800
#1  0x00577c94 in frame_register_unwind (frame=0x0, regnum=187, 
    optimizedp=0x7a1b20, lvalp=0x7fff68d4, addrp=0x7fff68d8, 
    realnump=0x7fff68e0, bufferp=0x7fff68c0)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/frame.c:187
#2  0x004f8534 in read_next_frame_reg (fi=0x7fff68c0, regno=29)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/mips-tdep.c:1592
#3  0x004f9e08 in heuristic_proc_desc (start_pc=715987376, limit_pc=715987376, 
    next_frame=0x0, cur_frame=1)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/mips-tdep.c:2140
#4  0x004fac8c in find_proc_desc (pc=715987376, next_frame=0x0, cur_frame=1)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/mips-tdep.c:2378
#5  0x004fb1c4 in mips_init_extra_frame_info (fromleaf=8002144, fci=0x10057370)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/mips-tdep.c:2477
#6  0x004e1bb4 in gdbarch_init_extra_frame_info (gdbarch=0x10061738, 
    fromleaf=0, frame=0x10057370)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/gdbarch.c:4436
#7  0x0057ad74 in get_prev_frame (next_frame=0x10057308)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/frame.c:1321
#8  0x00578ed4 in unwind_to_current_frame (ui_out=0x7a1a60, args=0x7a1a60)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/frame.c:496
#9  0x0056a500 in catcher (func=0x578ea4 <unwind_to_current_frame>, 
    func_uiout=0x10059530, func_args=0x10057308, func_val=0x7fff6c00, 
    func_caught=0x7fff6c04, errstring=0x0, mask=2)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/top.c:424
#10 0x0056a664 in catch_exceptions (uiout=0x10059530, 
    func=0x578ea4 <unwind_to_current_frame>, func_args=0x10057308, 
    errstring=0x0, mask=2)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/top.c:474
#11 0x00579048 in get_current_frame ()
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/frame.c:518
#12 0x0057a40c in reinit_frame_cache ()
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/frame.c:950
#13 0x00509ed0 in solib_add (pattern=0x0, from_tty=0, target=0x0, readsyms=1)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/solib.c:591
#14 0x004bba48 in handle_inferior_event (ecs=0x7fff6db8)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/infrun.c:2078
#15 0x004b91c8 in wait_for_inferior ()
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/infrun.c:1006
#16 0x004b8dc0 in proceed (addr=4294967295, siggnal=TARGET_SIGNAL_0, step=0)
    at /home/devel/kevinb/sourceware-mips64/src.baseline/gdb/infrun.c:804
...