Re: [RFC/RFA/hppa] unwind pc in bottom frame using correct register

[Randolph Chung <randolph@tausq.org>]

> --- hppa-tdep.c	1 Dec 2004 06:54:56 -0000	1.183
> +++ hppa-tdep.c	4 Dec 2004 04:15:30 -0000
> @@ -2185,6 +2185,12 @@ hppa_unwind_dummy_id (struct gdbarch *gd
>  static CORE_ADDR
>  hppa_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
>  {
> +  /* If unwinding the PC from the sentinel frame, then which register
> +     to read depends on the value of the status register.  Use
> +     hppa_target_read_pc(), it knows where to get the PC.  */
> +  if (target_has_execution && frame_relative_level (next_frame) < 0)
> +    return hppa_target_read_pc (inferior_ptid);
> +
>    return frame_unwind_register_signed (next_frame, HPPA_PCOQ_HEAD_REGNUM) & ~3;
>  }

this is wrong... perhaps you can do:

  if (frame_unwind_register_signed (next_frame, HPPA_FLAG_REGNUM) & 2)
    pc = frame_unsigned_register_signed (next_frame, 31);
  else
    pc = frame_unsigned_register_signed (next_frame, HPPA_PCOQ_HEAD_REGNUM);
  pc &= ~3;
  return pc;

this should work on corefiles too.....

the bit about HPPA_FLAG_REGNUM seems to be an hpux specific thing. I
think the syscall stub does something special so we try to return r31
instead of pcoqh. I haven't looked at this in detail...

i don't like having two versions of essentially the same function
either; Andrew mentioned in another email that this is a bug, but i
didn't understand if he meant this is a core-gdb bug or a hppa-specific
bug...

randolph
-- 
Randolph Chung
Debian GNU/Linux Developer, hppa/ia64 ports
http://www.tausq.org/