[Mesa-dev] [PATCH 08/12] configure.ac: deprecate --with-llvm-prefix

[Jan Vesely]

On Tue, 2018-11-06 at 12:09 +0000, Emil Velikov wrote:
> On Thu, 1 Nov 2018 at 16:13, Michel Dänzer <michel at daenzer.net> wrote:
> > On 2018-11-01 5:03 p.m., Jan Vesely wrote:
> > > On Wed, 2018-10-31 at 18:40 +0000, Emil Velikov wrote:
> > > > On Wed, 31 Oct 2018 at 17:41, Jan Vesely <jan.vesely at rutgers.edu> wrote:
> > > > > On Wed, 2018-10-31 at 17:22 +0000, Emil Velikov wrote:
> > > > > > On Wed, 31 Oct 2018 at 16:24, Michel Dänzer <michel at daenzer.net> wrote:
> > > > > > > On 2018-10-31 5:19 p.m., Jan Vesely wrote:
> > > > > > > > This might be a stupid question; is the LLVM_CONFIG env var remembered
> > > > > > > > between reconfigure (touch configure.ac; make) or do I need to provide
> > > > > > > > it explicitly every time configure is run?
> > > > > > > 
> > > > > > > I don't know the answer, but agree that would be a minimum requirement
> > > > > > > for this change.
> > > > > > > 
> > > > > > Nope, yet it's not really a minimum. LLVM_CONFIG has been around for
> > > > > > years, it will work for any Mesa checkout since its inception.
> > > > > > You can safely bisect Mesa and things will just work.
> > > > > 
> > > > > The question is; Do I have to do "LLVM_CONFIG=..." make every time
> > > > > bisect changes configure.ac?
> > > > > 
> > > > You can do (although there's other options if this one seems weird)
> > > > 
> > > > $ LLVM_CONFIG=... ../autogen.sh
> > > 
> > > That does not answer my question.
> > > 
> > > suppose the following sequence:
> > > $ LLVM_CONFIG=/usr/local/llvm-4/bin/llvm-config ../mesa-src/autogen.sh
> > > ...
> > >         llvm:            yes
> > >         llvm-config:     /usr/local/llvm-4/bin/llvm-config
> > >         llvm-version:    4.0.1
> > > ...
> > > $ make -j128
> > > $ touch ../mesa-src/configure.ac
> > > $ make -j128
> > > ...
> > >         llvm:            yes
> > >         llvm-config:     /usr/bin/llvm-config
> > >         llvm-version:    7.0.0
> > > ...
> > > 
> > > the second reconfigure silently reverted back to system default llvm.
> > > That's a loss of capabilty for me.
> > 
> > Thanks for checking, Jan. That's a NAK from me for this patch in the
> > current form.
> > 
> > FWIW, LLVM_CONFIG is available in the generated Makefiles, so it might
> > not be too hard to make this work with the environment variable. I don't
> > know the preferred way to do that however.
> > 
> Right, I misread the usecase :-( Sorry about that.
> The following works like a charm:
> 
> .../autogen.sh ac_cv_path_LLVM_CONFIG=/...
> make
> touch .../configure.ac
> make

ouch, that's rather ugly. What is the reason to prefer env var vs.
proper option (like --with-llvm-config)?
meson also seems to prefer env var for some reason.
I don't mind spending the time to send out the patches, but I'd like to
make sure it's not a wasted effort.

thanks,
Jan

> 
> > P.S. I only just now noticed the discrepancy between the commit log
> > talking about "deprecation", whereas the patch actually makes the option
> > ineffective. That's not what deprecation means. Also, I'm not sure how
> > this patch is related to the series' general theme of bumping the
> > minimum required LLVM version. Please don't bury unrelated patches in
> > large series.
> > 
> Merely following suite - see commit e2afa154e99071e8d51be88494cd1347ad113035
> The series does the following:
> - bumps the version
> - removes build-wise LLVM hacks - now dead
> - removes old LLVM codepaths - now dea
> 
> I could have split it in three, yet it seems like be a serious overkill.
> 
> That said, can we hear some directions/preferences of how to move
> things forward?
> I'm slightly worries that we may end up in the XKCD Workflow case :-(
> 
> Thanks
> Emil

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: This is a digitally signed message part
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20181107/cedd60a9/attachment.sig>