Re: [PATCH v4 4/4] gdb/doc: document '+' argument for 'list' command

[Matt Rice <ratmice@gmail.com>]

On Fri, Jul 14, 2023 at 4:30 PM Tom Tromey <tom@tromey.com> wrote:
>
> >>>>> "Bruno" == Bruno Larsen via Gdb-patches <gdb-patches@sourceware.org> writes:
>
> Bruno> Yeah, it does sound like some unfortunate bit of ambiguity. I'm sure
> Bruno> that "list +" is different to "list +[NSText initialize]" because the
> Bruno> code has a special case for "arg[0] == '+' && arg[1] == '\0'", so it
> Bruno> has to be a different case.
>
> Bruno> Would be nice if we could change this to a less ambiguous option, as
> Bruno> future work...
>
> I wonder if the ObjC code even works.  Most of the test cases can't even
> be compiled, and no one has maintained it in many years -- I think since
> before I worked on gdb.
>

Yeah most of the test cases rely upon stuff which the gcc objc runtime
removed and released before I noticed and could object to their
removal
(stuff like removing the Object class following suit from apples
removal of the same things).
At the time I had been working on fixing up and expanding the tests...
A good way forward might be to re-add them to gcc in a separate new
library
That might make it possible to get it working with some past and
future gcc versions.

Without that gdb would have to build it's own runtime for the
testsuite, or rely upon a 3rd party root object in order to test
things like allocating
objects, so we can invoke instance methods... I neither had enough
interest, nor thought it was a good idea for either gdb to maintain
such a thing
or alternately rely upon a external library just for testing...

Because without objects to actually instantiate gdb is pretty limited
in what it can test, and the code for allocating objects from the
runtime is quite runtime dependent.
As such I wouldn't be surprised if it were completely broken either.