Re: Raising our compiler requirements for 9.6

On Sun, Aug 16, 2015 at 05:58:17AM +0200, Andres Freund wrote:
> On 2015-08-15 23:50:09 -0400, Noah Misch wrote:
> > On Sun, Aug 16, 2015 at 02:03:01AM +0200, Andres Freund wrote:
> > > On 2015-08-15 12:47:09 -0400, Noah Misch wrote:
> > > > $ make -s PROFILE='-O0 -DPG_FORCE_DISABLE_INLINE=1'
> > > > pg_resetxlog.o: In function `fastgetattr':
> > > > /data/nmisch/src/pg/postgresql/src/bin/pg_resetxlog/../../../src/include/access/htup_details.h:754: undefined
referenceto `nocachegetattr'
 
> > > > pg_resetxlog.o: In function `heap_getattr':
> > > > /data/nmisch/src/pg/postgresql/src/bin/pg_resetxlog/../../../src/include/access/htup_details.h:783: undefined
referenceto `heap_getsysattr'
 
> > 
> > > What's the advantage of using STATIC_IF_INLINE over just #ifndef
> > > FRONTEND?
> > 
> > > In fact STATIC_IF_INLINE does *not* even help here unless we also detect
> > > compilers that support inlining but balk when inline functions reference
> > > symbols not available. There was an example of that in the buildfarm as
> > > of 2014, c.f. a9baeb361d63 . We'd have to disable inlining for such
> > > compilers.

> > Solaris Studio 12.3 (newest version as of Oct 2014) still does that
> > when optimization is disabled, and I place sufficient value on keeping
> > inlining enabled for such a new compiler.
> 
> Ah, that's cool. I was wondering generally how we could find an animal
> to detect that case once pademelon met its untimely (or timely by now?)
> end.

I would just make a "gcc -O0 -DPG_FORCE_DISABLE_INLINE=1" animal, since the
Solaris machine time supply is small.

> > The policy would then be
> > (already is?) to wrap in "#ifdef FRONTEND" any inline function that uses a
> > backend symbol.  When a header is dedicated to such functions, we might avoid
> > the whole header in the frontend instead of wrapping each function.  That
> > policy works for me.
> 
> Cool. I was wondering before where we'd document policy around
> this. sources.sgml?

+1.  Most coding rules go undocumented, but I'm in favor of changing that as
the opportunity arises.