Re: Header checking failures on LLVM-less machines

Hi,

On 2019-01-28 20:21:49 -0500, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > On 2019-01-28 19:51:22 -0500, Tom Lane wrote:
> >> I propose that we should fix this by making the whole bodies of those
> >> two headers be #ifdef USE_LLVM.
>
> > Hm, I think it's sufficient that we error out if llvm was configured,
> > we've sufficient buildfarm machines running with it enabled.
>
> That is not the point. The point is that you've broken a developer
> tool. I don't really care whether cpluspluscheck would work on
> some subset of buildfarm machines --- what I need is for it to work
> on *my* machine. It is not any more okay for the llvm headers to fail
> like this than it would be for libxml- or openssl- or Windows-dependent
> headers to fail on machines lacking respective infrastructure.
>
> (And yes, I realize that that means that cpluspluscheck can only
> check a subset of the header declarations on any particular machine.
> But there's no way around that.)

I don't think we are actually contradicting each other. The aim of that
error was to prevent pieces of code that aren't conditional on
--with-llvm from including llvmjit.h. I was, for a moment and wrongly,
thinking that we could style the header in a way that'd make it both for
safe for cpluspluscheck and still error in that case, but that was a
brainfart. But even leaving that brainfart aside, I'm not arguing
against adding those include guards, so ...?

I think the raison d'etre for that error has shrunk considerably anyway
- it was introduced before the LLVM including/linking code was separated
into it's own .so / directory.

Greetings,

Andres Freund