Re: How does GDB/MI give the current frame

Andrew Cagney
2004-07-08T22:15:30Z

> > > For the CLI, something like this:
> > >
> > > -> -interpreter cli "up"
> > > <- ~"info on new frame..."
> > > <- *select-frame,<frame-info>...
> > > <- done

Note that the interpreter case is key, it lets the GUI respond to
operations on the command line.

> > > with similar for -stack-select-frame:
> > >
> > > -> -stack-select-frame 1
> > > <- *select-frame,<frame-info>,....
> > > <- done
> > >
> > > Where, yes, <frame-info> would be constructed by calling frame code.
> > >
> > > -stack-info-frame would just be just:
> > >
> > > -> -stack-info-frame
> > > <- done,<frame-info>
> > >
> > > The important thing is that, in both cases, the GUI is being driven by
> > > the select-frame event.
> > >
> >
> > Cool !!
> >
> > One thing:
> >
> > -thread-select 2
> > ^done,...
> > -stack-select-frame 3
> > ^done
> > -thread-select 1
> > ^done,..
> > -thread-select 2
> > ^done,..
> >
> > If you would do "-stack-info-frame" now, you would notice that current
> > stackframe for thread 2 is not longer frame 3 but frame 0 !!
> > It this case would not it be appropriate to fire a "*select-frame" event.
>
> There would still be problems with displaying the values of variables.
> Neither variable objects or the CLI command, display, seem to take
> notice of the thread number.

``bug'' in current MI protocol. How would something like:

-thread 2 -<something else>
^done
-thread 2 -frame 3 -<something else>
-frame 3 -<something else>
^done

grab you? ``-thread'' and ``-frame'' select the thread/frame for
_just_ the period of that command. They would not alter the CLI's
selected thread/frame (the implementation would for the moment need to
be a crock but thats a separate problem :-).

This would let the GUI manipulate frames independant of the CLI.

> Second thing:
> Playing with MI, I've notice in between -var-update|-var-delete|etc ..
> operation the frame selection level was reset to 0, failing the other operations
> that was still assuming a certain frame level.
> Now is this an appropriate behaviour? or a bug? if it is appropriate should
> client recall -stack-select-frame XX all the time to make sure things are ok

``bug''. Actually major screwup in how GDB models threads (as in it
doesn't really :-)

> How about to put the thread-id part ot the event ?

So the event would be ``selected changed'' and generated when both
switching threads and frames? If it is useful, ok.

Andrew