bug#1191: How to contribute back changes for Emacs on Solaris

[Ali Bahrami <ali_gnu@emvision.com>]

Dan Nicolaescu wrote:
> Ali Bahrami <ali_gnu@emvision.com> writes:
> 
>   > This message is a follow up to one I sent to emacs-devel
>   > last July:
>   > 
>   > 	http://lists.gnu.org/archive/html/emacs-devel/2008-07/msg00070.html
>   > 
>   > The question had to do with why emacs wasn't using dldump()
>   > to produce the dumped executable under Solaris. It had been using it
>   > up until 2002, at which point it was commented out, and it wasn't
>   > clear why. No one knew the reason, and the consensus was "try it and see".
>   > 
>   > Since then, I've done some work to integrate emacs with
>   > OpenSolaris as a standard package. I turned on dldump(),
>   > and have been using the emacs binaries built with it daily
>   > since July without issue.
>   > 
>   > So now, I have some things I'd like to send back up stream
>   > and get integrated into the emacs distribution:
>   > 
>   > 	- Man pages for things installed to /usr/bin that didn't
>   > 	  already have a manpage:
>   > 		b2m.1
>   > 		ebrowse.1
>   > 		grep-changelog.1
>   > 		rcs-checkin.1
>   > 	- Small changes to config.guess and configure to properly
>   > 	  detect amd64 hardware running Solaris.
>   > 	- Use dldump() instead of the generic ELF dump code
>   > 	  under Solaris.
>   > 	- Use the system malloc under Solaris (at least with
>   > 	  amd64, emacs crashes without this).
>   > 
>   > The manpages can be viewed at:
>   > 
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/man/man1/b2m.1
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/man/man1/ebrowse.1
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/man/man1/grep-changelog.1
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/man/man1/rcs-checkin.1
> 
> Hopefully someone else can address these changes, I'll address the rest.
> 
>   > and the patches at:
>   > 
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/patch/config.guess.patch
> 
> Please send this one to config-patches@gnu.org.
> We don't modify this file directly in emacs, it gets updated from time
> to time from:
> http://savannah.gnu.org/cgi-bin/viewcvs/*checkout*/config/config/config.guess
> 
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/patch/configure.patch
> 
> This one is fine, but it depends on the previous one being installed by
> the config.guess maintainers.
> BTW, do you know anything about emacs running on  powerpc*-*-solaris2*
> or  rs6000-*-solaris2* ? configure.in mentions them.
> 
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/patch/dldump.patch
> 
> Last time when you posted this you said you were going to test it on
> multiple Solaris versions.  Have you managed to do that?  This is also
> valid for the next patch.
> 
>   > http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/emacs/augment/patch/sysmalloc.patch
>   > 
>   > The patches are for emacs 22.1. I've examined 22.3, and the
>   > changes are applicable there as well. If 22.1 diffs are OK,
>   > that's easiest for me, but if not, then please let me know what
>   > I need to supply. These diffs are all very short, affecting a
>   > small number of lines in each file.
> 
> AFAIK the 22.x branch is closed, there will not be any more releases
> from that branch.  But we could install your changes on HEAD.
> 
> Thanks
> 
>         --dan

Hi Dan,

    I will send the config.guess patch to config-patches@gnu.org today.
In the meantime, the change to configure should be safe to make immediately.

I'm only concerned about getting these changes into HEAD. My patches are
for 22.1, but only because that's the version I used for this work. So
that would be great. If you can use these old patches as a basis for making
the necessary changes (which are small) to HEAD, then that would be a big
time saver for me, and much appreciated. If you need specific patches against
HEAD, then point me at it and I'll put some together.

I only know a little about emacs on the power architecture: Sun funded
a port during the 90's. As a point of irrelevant trivia, it was a little endian
system, and not big endian as one might expect. For reasons that are lost
in time, the port was completed, and a few pre-releases were made, but it never
shipped as a standard product, wasn't updated with the main branch, and quickly
faded away. My only quess is that powerpc*-*-solaris2* and rs6000-*-solaris2*
(the rs6000 also being a Power architecture system) date from this port, and
have probably never had more than a small handful of users --- probably none for
a decade or so.

There are people involved in a PowerPC port with OpenSolaris now (big endian,
a completely different deal) starting with the modern OpenSolaris code base.
I'm not sure if there's much overlap between the old stuff in emacs for power
on Solaris, and what would be needed for a modern version. There's probably more
affinity with the modern Linux ppc definitions.

About testing different Solaris versions, I remember the question being asked.
I thought I replied at the time, but can't be sure. In any event, the answer is
no. My interest is with the modern Solaris, which is OpenSolaris, and Solaris 10.
That's all I've tested, and I apologize for not having said that
directly. There are several reasons:

	- Maximizing the value of the time I spend on this project
	- No evidence of an actual problem with dldump for older Solaris,
	  including the fact that xemacs has apparently been using it
	  all along
	- The fact that the generic ELF dump code does work, and can be
	  used for those old releases. It isn't as nice as the dldump'd
	  version, but the resulting executables would run as well as they
	  ever did. Hence, there's an easy fallback if something did come up.

None of which, I admit, is actual testing. I feel that the risk of switching
the old versions to dldump() is minimal. However, if you feel more comfortable
applying this change such that it only applies to Solaris 10 and newer, that
would also be fine.

Thanks...

- Ali