Re: prev_pc problem on ia64

[Andrew Cagney <ac131313@redhat.com>]

(I'll ignore the debug info :-)
>  > Same function compiled for i686:
>  > 
>  >    Special opcode 76: advance Address by 5 to 0x804839e and Line by 1 to 31
>  >    Special opcode 230: advance Address by 16 to 0x80483ae and Line by 1 to 32
>  >    Special opcode 146: advance Address by 10 to 0x80483b8 and Line by 1 to 33
>  >    Special opcode 160: advance Address by 11 to 0x80483c3 and Line by 1 to 34
>  > 
>  > I have a patch whereby I reset prev_pc in infrun.c:init_execution_control_state():
>  > 
>  >    if (prev_pc != 0)
>  >      prev_pc = read_pc ();
>  > 
>  > prior to setting the ecs->sal.  This works for me in both scenarios.  The check for
>  > 0 was needed because I get a failure on the ia64 trying to read the pc too early when
>  > the psr register was invalid.
>  > 
> 
> maybe read_pc should return an error code? Ah wait, it errors out, so
> you should encapsulate that in a catch_errors().

The `prev_pc != 0' test is definitly wrong - that will only work when 
GDB first starts.  Provided the target_has_execution (?), there 
shouldn't be an error (if there is, GDB's in bad shape :-), so the 
change should always assign a value to prev_pc and, conditional on 
target_has_execution, use the value of read_pc().

I'm also left wondering if the prev_func_name assignment in:

> static void
> stop_stepping (struct execution_control_state *ecs)
> {
>   if (target_has_execution)
>     {
>       /* Assuming the inferior still exists, set these up for next
>          time, just like we did above if we didn't break out of the
>          loop.  */
>       prev_pc = read_pc ();
>       prev_func_name = ecs->stop_func_name;
>     }
> 
>   /* Let callers know we don't want to wait for the inferior anymore.  */
>   ecs->wait_some_more = 0;
> }

should also be moved to init_execution_control_state, and both of those 
assignments should be deleted.

Is it possible to move both of these into the ECS state?

> please post the patch to gdb-patches. It's hard to judge, like this.

Yes.

Andrew