Re: [PATCH] Skip llvm bytecode generation if LLVM is missing

On Thu, 19 Mar 2020 at 18:47, Peter Eisentraut <
peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:

> On 2020-03-15 02:28, Craig Ringer wrote:
> > On Fri, 13 Mar 2020 at 15:04, Andres Freund <andres(at)anarazel(dot)de
> > <mailto:andres(at)anarazel(dot)de>> wrote:
> >
> > On 2020-03-13 14:08:12 +0800, Craig Ringer wrote:
> > > The alternative would be to detect a missing clang and emit a
> > much more
> > > informative error than the current one that explicitly suggests
> > retrying
> > > with
> > >
> > > make with_llvm=no
> > >
> > > or setting with_llvm=no in the environment.
> >
> > That, that, that's what I suggested upthread?
> >
> >
> > Yes, and I still don't like it. "with_llvm" is the actual
> > already-working option. I'd rather make this not randomly explode for
> > users, but failing that we can just hack the Makefile in the rpms for
> > EL-7 (where it's a particular mess) and rely on an error message for
> > other cases.
>
> I don't really get the problem. with_llvm=no works, so it can be used.
>
> Options that automatically disable things based on what is installed in
> the build environment are bad ideas. For instance, we on purpose don't
> have configure decide anything based on whether readline is installed.
> Either you select it or you don't, there is no "auto" mode.
>
>
Fine with me. I wrote it before identifying that with_llvm=no was a viable
workaround.

The whole thing is a bit ugly, but if the fix isn't clearly better than the
problem the fix shouldn't go in. This way it'll be searchable-for at least.

I think we'll be adopting some kind of ugly workaround like this for the
CentOS 7 packages in PGDG yum because they're a bit of a special case,
since the llvm support requires an additional 3rd party that isn't declared
as a build-depend on the devel package. But that can be done at packaging
level + a small patch applied during package builds for CentOS 7 only.

Withdrawn.

--
Craig Ringer http://www.2ndQuadrant.com/
2ndQuadrant - PostgreSQL Solutions for the Enterprise