Re: RFA: Recognize 'x' in response to 'p' packet

[Jim Blandy <jimb at redhat dot com>]

Jim Blandy <jimb@redhat.com> writes:

> Daniel Jacobowitz <drow@false.org> writes:
> > My real question, though, is what you needed this for - and whether
> > marking the register unavailable fixes it.
> 
> The Red Hat Debug Agent generates replies to 'p' packets that contain
> 'x's.  GDB generally seems to work, but 'info thread' fares poorly.
> Simply parsing the response at all should fix the problem; I'll make
> sure that marking the register as unavailable doesn't cause any new
> problems.
> 
> Thanks for the review!

Okay, here's the revised patch, against the properly re-indented
sources.  Tested against RDA.

2004-12-17  Jim Blandy  <jimb@redhat.com>

	* remote.c (fetch_register_using_p): Recognize a register value
	starting with 'x' as indicating an unfetchable register.

Index: gdb/remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.156
diff -c -p -r1.156 remote.c
*** gdb/remote.c	21 Dec 2004 21:24:56 -0000	1.156
--- gdb/remote.c	23 Dec 2004 15:43:46 -0000
*************** fetch_register_using_p (int regnum)
*** 3192,3216 ****
    p += hexnumstr (p, regnum);
    *p++ = '\0';
    remote_send (buf, rs->remote_packet_size);
!   if (buf[0] != 0 && buf[0] != 'E')
      {
!       p = buf;
!       i = 0;
!       while (p[0] != 0)
! 	{
! 	  if (p[1] == 0)
! 	    {
! 	      error ("fetch_register_using_p: early buf termination");
! 	      return 0;
! 	    }
! 	  regp[i++] = fromhex (p[0]) * 16 + fromhex (p[1]);
! 	  p += 2;
! 	}
!       regcache_raw_supply (current_regcache, regnum, regp);
        return 1;
      }
  
!   return 0;
  }
  
  static void
--- 3192,3227 ----
    p += hexnumstr (p, regnum);
    *p++ = '\0';
    remote_send (buf, rs->remote_packet_size);
! 
!   /* If the stub didn't recognize the packet, or if we got an error,
!      tell our caller.  */
!   if (buf[0] == '\0' || buf[0] == 'E')
!     return 0;
! 
!   /* If this register is unfetchable, tell the regcache.  */
!   if (buf[0] == 'x')
      {
!       regcache_raw_supply (current_regcache, regnum, NULL);
!       set_register_cached (regnum, -1);
        return 1;
      }
  
!   /* Otherwise, parse and supply the value.  */
!   p = buf;
!   i = 0;
!   while (p[0] != 0)
!     {
!       if (p[1] == 0)
!         {
!           error("fetch_register_using_p: early buf termination");
!           return 0;
!         }
! 
!       regp[i++] = fromhex (p[0]) * 16 + fromhex (p[1]);
!       p += 2;
!     }
!   regcache_raw_supply (current_regcache, regnum, regp);
!   return 1;
  }
  
  static void