On 5 October 2017 at 18:11, Tom Stellard <tstel...@redhat.com> wrote: > On 10/05/2017 08:40 AM, Emil Velikov wrote: >> On 5 October 2017 at 16:16, Tom Stellard <tstel...@redhat.com> wrote: >>> On 10/05/2017 06:33 AM, Michel Dänzer wrote: >>>> On 05/10/17 12:19 PM, Emil Velikov wrote: >>>>> From: Emil Velikov <emil.veli...@collabora.com> >>>>> >>>>> A while back Michel reported that LLVM has symbol versioning to avoid >>>>> symbol collisions. Based on observations LLVM 5.0 is the first upstream >>>>> version to actually has it. >>>> >>>> Not exactly. Adam Jackson originally added symbol versioning in LLVM 3.6 >>>> (in SVN r214418), but it was only effective when LLVM was built with >>>> autotools. As of 5.0, it's effective with cmake as well. >>>> >>>> >>>>> Since symbol collisions do come up again and again (fortunately not so >>>>> often) let's flip the switch back to static. >>>> >>>> It seems a bit weird to make this change now, that LLVM is solving the >>>> issue for good. But I don't feel strongly about it. >>>> >>>> >>> >>> I agree with this, symbol versioning should solve the issues with symbol >>> collisions, so why change this now? >>> >> LLVM with symbol versioning as not so widely used as I/we hope it was. >> See the list in my other reply. >> > > I looked at the list, but my preference is still that LLVM shared libraries > should remain the default. What is motivating the change to static by > default? Do the symbol collision problems affect most users? > > Static linking really just works around a bug/deficiency in older versions > of LLVM and I think this is something distros should be handling. > > static linking has the added downside of build breakage when LLVM changes > the component names for it's static libraries, which can be a pain. Not > to mention the increase in library size. > > As a compromise, if shared libraries are really causing a lot of issues, > then maybe you could make static the default for for LLVM < 5.0, but I really > prefer using shared libraries for all versions. > Looking the whole thing from another angle:
I noticed that Fedora (RHEL?) has been using statlc libstdc++ for ~2 years. In the packaging [1] there is this comment: # C++ note: we never say "catch" in the source. we do say "typeid" once, # in an assert, which is patched out above. LLVM doesn't use RTTI or throw. # # We do say 'catch' in the clover and d3d1x state trackers, but we're not # building those yet. d3d1x is long gone, but seemingly clover is build these days. Thus static linking LLVM is the way right approach in that case. Of course - everyone who knows the pros/cons of the toggle can adjust it to their needs. I hope that with these in mind I could get your blessing (ack) on the patch? Thanks Emil [1] http://pkgs.fedoraproject.org/cgit/rpms/mesa.git/tree/mesa.spec#n387 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
