[RFC] small change for better error reporting in remote.c

[Michael Snyder <msnyder@vmware.com>]

[-- Attachment #1: Type: text/plain, Size: 703 bytes --]

AFAICT, this has been mildly broken forever.

If you look at store_register_using_P and fetch_register_using_p,
they both call remote_send, followed by packet_ok, and then send
error if PACKET_ERROR.

Unfortunately the PACKET_ERROR path is dead code, because remote_send
already bails with a much more general (ie. less useful) error msg
if we get back an Exx reply.

Most of us will have never seen this happen, because how can a
remote target fail to write a register?

But it can happen when the target is a replay recording as with
Virtutech and VMware targets.

This change is to give a more helpful error message, eg.
'Could not write register "eip"', as opposed to
'Remote failure reply: E00'.



[-- Attachment #2: errmsg.txt --]
[-- Type: text/plain, Size: 1969 bytes --]

2009-07-29  Michael Snyder  <msnyder@vmware.com>

	* remote.c (store_register_using_P): Call putpkt and getpkt
	directly instead of calling remote_send.
	(store_register_using_G): Ditto.
	(fetch_register_using_p): Ditto.

Index: remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.364
diff -u -p -r1.364 remote.c
--- remote.c	14 Jul 2009 21:40:30 -0000	1.364
+++ remote.c	29 Jul 2009 23:52:27 -0000
@@ -4873,7 +4873,8 @@ fetch_register_using_p (struct regcache 
   *p++ = 'p';
   p += hexnumstr (p, reg->pnum);
   *p++ = '\0';
-  remote_send (&rs->buf, &rs->buf_size);
+  putpkt (rs->buf);
+  getpkt (&rs->buf, &rs->buf_size, 0);
 
   buf = rs->buf;
 
@@ -5121,7 +5122,8 @@ remote_prepare_to_store (struct regcache
    packet was not recognized.  */
 
 static int
-store_register_using_P (const struct regcache *regcache, struct packet_reg *reg)
+store_register_using_P (const struct regcache *regcache, 
+			struct packet_reg *reg)
 {
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
   struct remote_state *rs = get_remote_state ();
@@ -5141,7 +5143,8 @@ store_register_using_P (const struct reg
   p = buf + strlen (buf);
   regcache_raw_collect (regcache, reg->regnum, regp);
   bin2hex (regp, p, register_size (gdbarch, reg->regnum));
-  remote_send (&rs->buf, &rs->buf_size);
+  putpkt (rs->buf);
+  getpkt (&rs->buf, &rs->buf_size, 0);
 
   switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_P]))
     {
@@ -5189,7 +5192,10 @@ store_registers_using_G (const struct re
   /* remote_prepare_to_store insures that rsa->sizeof_g_packet gets
      updated.  */
   bin2hex (regs, p, rsa->sizeof_g_packet);
-  remote_send (&rs->buf, &rs->buf_size);
+  putpkt (rs->buf);
+  getpkt (&rs->buf, &rs->buf_size, 0);
+  if (rs->buf[0] == 'E')
+    error (_("Could not write registers"));
 }
 
 /* Store register REGNUM, or all registers if REGNUM == -1, from the contents