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Re: generic_prepare_to_proceed vs. Ctrl-C


Jonathan,

I see what you are trying to do, and I think it is a good idea.

Now let's get to the details of your patch.  The main problem I have with 
your patch is that it leaves that comment before switching the ptid's in an 
odd state.  I'd change it to something like "Switch back to WAIT_PID 
thread.".  Also, your change before the call to breakpoint_here_p() needs a 
better comment explaining why we only return 1 if there is a breakpoint there.

One last thing.  Your patch fixes the generic implementation of 
PREPARE_TO_PROCEED, but it doesn't do anything for the 4 other 
implementations of PREPARE_TO_PROCEED.  These are located in: hppa-tdep.c, 
lin-lwp.c, linux-thread.c, and m3-nat.c.  At bare minimum you might add a 
FIXME comment to each of the 4 other implementations describing what needs 
doing.  Of course if you have the time and are braver than I was, you could 
try switching the Linux port to just use the generic version.

Jonathan Larmour wrote:

> David S's recently added generic_prepare_to_proceed() only takes account of
> stopping at a breakpoint and switching threads. It does not deal with
> stopping due to a Ctrl-C and switching threads. The below patch fixes this.
> 
> Okay to check in?
> 
> 2001-05-22  Jonathan Larmour  <jlarmour@redhat.com>
> 
> 	* arch-utils.c (generic_prepare_to_proceed): Allow for having
> 	stopped due to a Ctrl-C as well as breakpoints.
> 
> Jifl
> 
> Index: arch-utils.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/arch-utils.c,v
> retrieving revision 1.27
> diff -u -5 -p -r1.27 arch-utils.c
> --- arch-utils.c	2001/05/10 18:36:26	1.27
> +++ arch-utils.c	2001/05/22 22:19:29
> @@ -256,26 +256,26 @@ generic_prepare_to_proceed (int select_i
>    struct target_waitstatus wait_status;
>  
>    /* Get the last target status returned by target_wait().  */
>    get_last_target_status (&wait_ptid, &wait_status);
>  
> -  /* Make sure we were stopped at a breakpoint.  */
> +  /* Make sure we were stopped either at a breakpoint, or because
> +     of a Ctrl-C.  */
>    if (wait_status.kind != TARGET_WAITKIND_STOPPED
> -      || wait_status.value.sig != TARGET_SIGNAL_TRAP)
> +      || (wait_status.value.sig != TARGET_SIGNAL_TRAP &&
> +          wait_status.value.sig != TARGET_SIGNAL_INT))
>      {
>        return 0;
>      }
>  
>    if (!ptid_equal (wait_ptid, minus_one_ptid)
>        && !ptid_equal (inferior_ptid, wait_ptid))
>      {
>        /* Switched over from WAIT_PID.  */
>        CORE_ADDR wait_pc = read_pc_pid (wait_ptid);
>  
> -      /* Avoid switching where it wouldn't do any good, i.e. if both
> -         threads are at the same breakpoint.  */
> -      if (wait_pc != read_pc () && breakpoint_here_p (wait_pc))
> +      if (wait_pc != read_pc ())
>  	{
>  	  if (select_it)
>  	    {
>  	      /* User hasn't deleted the breakpoint.  Switch back to
>  		 WAIT_PID and return non-zero.  */
> @@ -286,12 +286,15 @@ generic_prepare_to_proceed (int select_i
>  	      flush_cached_frames ();
>  	      registers_changed ();
>  	      stop_pc = wait_pc;
>  	      select_frame (get_current_frame (), 0);
>  	    }
> -
> -	  return 1;
> +          /* Step over the breakpoint if there is one here. */
> +          if (breakpoint_here_p (wait_pc))
> +            {
> +	      return 1;
> +            }
>  	}
>      }
>    return 0;
>    
>  }
> 
> 



-- 
David Smith
dsmith@redhat.com
Red Hat, Inc.
http://www.redhat.com
256.704.9222 (direct)
256.837.3839 (fax)


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