Re: RFC: selected frame in read_var_value

[Andrew Cagney <ac131313@redhat.com>]

> On Thu, Aug 07, 2003 at 01:45:28PM -0400, Andrew Cagney wrote:
> 
>> >Thoughts on this?  I observed one case where the selected frame hadn't been
>> >initialized yet: when checking watchpoint values.  Oops!  The condition
>> >matches the case in which get_current_frame () can be reasonably expected 
>> >to
>> >succeed.  There are a couple other places that need this same check, mostly
>> >functions which will work on globals as well as locals.
> 
>> 
>> I think the caller, and not this code, should be the one deciding 
>> if/when a get_selected_frame should be called.  Otherwize the dependance 
>> on global state remains.
> 
> 
> The callers don't know any more than we do.  Take a look at some of
> them - several callers don't take frame arguments, and work both when
> the program is running and when it isn't.  If you want to cut down on
> the global state dependence, I guess you'd have to push this up through
> every caller, so that it could eventually be pushed even higher?

Yep, welcome to my world :-)

> Me, I was just fixing the regression caused by lazily selecting a
> frame.  I wasn't planning on redesigning interfaces all through the
> block and variable layers; and fixing this really does go quite far up.
> For instance it works back to block_innermost_frame, which can return
> NULL.

What about something like this as a step sideways:

> if (frame == NULL)
>   frame = deprecated_safe_get_selected_frame ();

where deprecated_safe_get_selected_frame() would contain those sanity 
checks?

Andrew