Retiring in-tree GDB

[John Baldwin]

On Wednesday, July 20, 2016 01:20:34 PM Sean Bruno wrote:
> 
> On 07/20/16 13:00, John Baldwin wrote:
> > On Tuesday, October 20, 2015 01:36:28 PM John Baldwin wrote:
> >> When this topic was last raised (by Warner I believe), the primary objection
> >> (certainly my main one) was that the in-tree kgdb was the only kernel debugger
> >> available.  kgdb is now available via the devel/gdb port in ports (and as of
> >> last week was enabled by default, so 'pkg install gdb' will get you a kgdb
> >> binary).  The kgdb in ports is in general superior to the one in the base
> >> system.  It is a cross debugger by default (and with my pending patches to
> >> libkvm it even supports cross debugging of vmcores).
> >>
> >> There are some issues still with devel/gdb: namely it does not currently
> >> support some of the platforms supported by our in tree gdb such as arm and
> >> mips.  For these platforms I think the in-tree gdb will need to remain until
> >> there is a suitable alternative.
> >>
> >> However, I would like to propose that we retire the in-tree GDB for some of
> >> our platforms (namely x86) for 11.  In particular, I think we should default
> >> to enabling lldb and disabling gdb for platforms that meet the following
> >> criteria:
> >>
> >> 1) devel/gdb works including thread and kgdb support
> >> 2) lldb works
> >>
> >> We could perhaps be more aggressive and handle lldb and gdb toggles
> >> independently, but I think we want to ship some sort of userland debugger
> >> out of the box on all of our platforms.  The question I think might be if
> >> we end up with platforms where 1) is true but 2) is not (such as powerpc).
> >>
> >> I believe that these conditions are only true for x86 currently.
> >>
> >> Comments?
> > 
> > I believe I've fixed the one last thing that was depending on /usr/bin/gdb
> > (crashinfo) to use devel/gdb if it is present.  I'd either like to disable
> > the base gdb on amd64 in the next week or so on HEAD, or perhaps if people are
> > really gutsy, disable it for all platforms on HEAD.  We still don't have kgdb
> > in ports for non-x86 (though for ppc at least kgdb in ports and base is
> > equally dysfunctional).
> > 
> > However, to start with:
> > 
> > 1) Does anyone have a reason to keep /usr/bin/gdb on amd64?
> > 
> > 2) Does anyone have a reason to keep /usr/bin/gdb on !amd64?
> > 
> 
> I don't have an immediate use case in the mips/mips64 case.  Should
> ports "just work" here or do I need some kind of "cross gdb"?

ports gdb does not yet work on mips.  Once it supports mips it will work as
both a native and cross debugger, but it just doesn't know about FreeBSD/mips
at all.  Does /usr/bin/gdb work on mips?

-- 
John Baldwin