Re: [patch] fallback unwinder for hppa

[Andrew Cagney <cagney@gnu.org>]

> +  int pcoqt = (regnum == PCOQ_TAIL_REGNUM);
> +  struct gdbarch *gdbarch = get_frame_arch (next_frame);
> +  int regsize = register_size (gdbarch, PCOQ_HEAD_REGNUM);
> +
> +  if (pcoqt)
> +    regnum = PCOQ_HEAD_REGNUM;
> +
> +  trad_frame_prev_register (next_frame, saved_regs, regnum,
> +                            optimizedp, lvalp, addrp, realnump, valuep);
> +
> +  if (pcoqt)
> +    store_unsigned_integer (valuep, regsize, 
> +		      	    extract_unsigned_integer (valuep, regsize) + 4);
> +}

It should be possible to encode this information directly in the 
saved_regs array.  For instance, near the end, round:

> +  cache->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM);
> +
> +  if (trad_frame_addr_p (cache->saved_regs, RP_REGNUM))
> +    {
> +      cache->saved_regs[RP_REGNUM].addr += cache->base;
> +      cache->saved_regs[PCOQ_HEAD_REGNUM] = cache->saved_regs[RP_REGNUM];
> +    }
>    else
>      {
> -      trad_frame_prev_register (next_frame, info->saved_regs, regnum,
> -				optimizedp, lvalp, addrp, realnump, valuep);
> +      ULONGEST rp = frame_unwind_register_unsigned (next_frame, RP_REGNUM);
> +      trad_frame_set_value (cache->saved_regs, PCOQ_HEAD_REGNUM, rp);
>      }
> +

have:

    saved_regs[PCOQ_TAIL_REGNUM] = saved_regs[PCOQ_HEAD_REGNUM]

andrew