Date: Wed, 20 Jul 2016 13:19:46 -0700 From: John Baldwin <jhb@freebsd.org> To: freebsd-arch@freebsd.org Cc: Sean Bruno <sbruno@freebsd.org> Subject: Re: Retiring in-tree GDB Message-ID: <3871457.xzmrTRH8AM@ralph.baldwin.cx> In-Reply-To: <068a0167-1d5d-a437-60e7-b74e407060a2@freebsd.org> References: <2678091.es0AGJQ0Ou@ralph.baldwin.cx> <4450836.nX37FfBzNy@ralph.baldwin.cx> <068a0167-1d5d-a437-60e7-b74e407060a2@freebsd.org>
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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
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