lib/gdb.exp: Don't loop infinitly on download attempts

[Stan Shebs]

   From: Andrew Cagney <ac131313@cygnus.com>
   Date: Wed, 06 Oct 1999 13:00:25 +1000

   Wed Oct  6 12:05:58 1999  Andrew Cagney  <cagney@b1.cygnus.com>

	   * lib/gdb.exp (gdb_run_cmd): Give up after five download attempts.

The theory is attractive, although I would suggest three download attempts,
two seems to be giving up too quickly, five seems excessive.  But I have
a question about the logic:

   *************** proc gdb_run_cmd {args} {
   *** 204,209 ****
   --- 207,217 ----
	       }
	       -re "No symbol \"start\" in current.*$gdb_prompt $" {
		   send_gdb "jump *_start\n";
   + 		set load_attempts [expr $load_attempts - 1]
   + 		if [expr $load_attempts <= 0] {
   + 		    perror "Load failed"
   + 		    return
   + 		}
		   exp_continue;

So what's happening here is that jumping to "start" (actually should
be matching "$start", that's what was sent) has failed, so we try a
fallback of jump *_start instead.  But then, instead of expecting a
reply, we immediately count down load_attempts and return if 0,
counting this as a failure. Meanwhile, the jump to _start may actually
have succeeded...

I think the right thing to do is to start the countdown in gdb_load
and then count down/fail on the error returns in gdb_run_cmd rather
than the continues.

								Stan