Re: [RFC][PATCH 0/6] Step program considering the source column information

[Hannes Domani <ssbssa@yahoo.de>]

 Am Samstag, 16. Mai 2020, 20:45:30 MESZ hat Pedro Alves <palves@redhat.com> Folgendes geschrieben:

> Hi,
>
> Cool!  A few years back, Antoine Tremblay prototyped this
> as well, but it only worked with Clang, because back then
> GCC didn't output column information.  I complained about it
> to Jakub Jelinek, who in his usual awesomeness quickly implemented
> GCC support.  :-)  Quite nice that we're finally getting closer to
> actually making use of it in GDB.
>
> You can still find Antoine's prototype here:
>
> https://github.com/hexa00/binutils-gdb/commits/statement-stepping

I didn't know about that, interesting.
Is there some reason why this wasn't included in gdb back then?


> It would likely be interesting if you could take a look and compare
> approaches.  You should be able to borrow any code you find useful, since
> he was working for Ericsson at the time, and had a copyright assignment.

I just checked it out for a bit.

The actual implementation in process_event_stop_test() is a lot simpler,
I will have to try it out and compare the result, maybe that means mine
is unnecessary complicated.

And the calculation of the column indicator position is also more complicated
in mine, but that's because I had to account for the escape sequences of
the syntax highlighting.


> On the name of the new commands -- for a user, thinking in terms
> "step until next column" doesn't make sense IMO.  What the user really wants
> is "step until next statement".  Column information in the debug
> info enables this, but it's an implementation detail.
> In Antoine's version, he thus had "nexts" instead of "nextc", which
> sounds better to me:
>
>   add_com ("nexts", class_run, nexts_command, _("\
> Step program by statement, proceeding through subroutine calls.\n\
> Usage: nexts [N]\n\
> Unlike \"steps\", if the current source line calls a subroutine,\n\
> this command does not enter the subroutine, but instead steps over\n\
> the call, in effect treating it as a single statement."));
>   add_com_alias ("ns", "nexts", class_run, 1);

Yes, he has nexts (ns) and steps (ss), I don't really mind either way.
I used nextc/stepc because that was suggested in PR25913.


Hannes