Re: [patch] Support LLVM 7

Hi,

On 2018-09-16 09:48:34 +0200, Christoph Berg wrote:
> Re: To Andres Freund 2018-09-12 <20180912210734(dot)GB5666(at)msg(dot)df7cb(dot)de>
> > I plan to switch postgresql-11.deb to LLVM 7 over the next days
> > because of the support for non-x86 architectures
>
> I did an upload of postgresql-11 beta3 with llvm 7 enabled on the
> architectures where it is available (or supposed to become available),
> that is, on !alpha !hppa !hurd-i386 !ia64 !kfreebsd-amd64 !kfreebsd-i386 !m68k !sh4.

Cool. No idea why kfreebsd is on that list, but that's not really a
postgres relevan concern...

> There are two failures:
> https://buildd.debian.org/status/logs.php?pkg=postgresql-11&ver=11~beta3-2
>
> sparc64 fails with a lot of these in the log:
>
> FATAL: fatal llvm error: Invalid data was encountered while parsing the file

Hm, that sounds like a proper serious LLVM bug. If it can't read bitcode
files it wrote, something is seriously wrong.

> powerpc (the old 32-bit variant) has a lot of "server closed the
> connection unexpectedly" in the regression logs, and one SIGILL:
>
> 2018-09-15 10:49:25.052 UTC [26458] LOG: server process (PID 26527) was terminated by signal 4: Illegal instruction
> 2018-09-15 10:49:25.052 UTC [26458] DETAIL: Failed process was running: SELECT '' AS tf_12, BOOLTBL1.*, BOOLTBL2.*
> FROM BOOLTBL1, BOOLTBL2
> WHERE BOOLTBL2.f1 <> BOOLTBL1.f1;
> 2018-09-15 10:49:25.052 UTC [26458] LOG: terminating any other active server processes

Hm. Is there any chance to get a backtrace for this one? This could,
although I think less likely so, also be a postgres issue
(e.g. generating code for the wrong microarch).

> Both smell more like LLVM bugs rather than PostgreSQL, so I guess we
> can dub that a success. I'll disable JIT on these architectures for
> the next upload.

Ok.

Greetings,

Andres Freund