Re: Multiplexed registers and invalidating the register cache

[Andrew Cagney <cagney@gnu.org>]

Yes, on all counts!


> Andrew Cagney wrote:
> 
>>
>> Oops, yes, pass the current_target (I ment that it shouldn't have a parameter trying to tell the observers anything beyond the fact that the target has changed).  (the sed script generates () instead of (void)).
> 
> 
> Ok.
> 
>> There are architectures where registers live in memory so the information is simply misleading.
> 
> 
> Ok, I'm convinced.  (Thanks for clarifying.)
> 
>> Eventually, yes.  The two can co-habitate for a bit, first just:
>>
>> - add the observer
> 
> 
> Ok.  observer.texi gets the following lines added:
> 
>   @deftypefun void target_changed (struct target_ops *@var{current_target})
>   The target's register contents has changed.
>   @end deftypefun
> 
> (Proper patch delayed until I've got all the pieces in place.)
> 
>> - add code to frame.c and regcache.c to register themselves
> 
> 
> I'm sorry; this is the part I don't get - my skull must be getting really thick.  Are you saying that frame.c and regcache.c should register an observer each for the target_changed event, like this (frame.c):
> 
>   void
>   frame_observer_target_changed (struct target_ops *current_target)
>   {
>     flush_cached_frames ();
>   }
>   observer_attach_target_changed (frame_observer_target_changed);
> 
> and (regcache.c):
> 
>   void
>   regcache_observer_target_changed (struct target_ops *current_target)
>   {
>     registers_changed ();
>   }
>   observer_attach_target_changed (regcache_observer_target_changed);
> 
>> - add code to the problem area to trigger the observer
> 
> 
> Ok; something like (example from valops.c):
> 
>         if (deprecated_register_changed_hook)
>           deprecated_register_changed_hook (-1);
>         target_changed_event ();
> +       observer_notify_target_changed (current_target);
>         break;
>        }
> 
> -- 
> Orjan Friberg
> Axis Communications
> 
>