Re: [HACKERS] Reorganization of spinlock defines

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Yes, we could do just the configure warning, then plaster tests into the
> > port files to try to hit all the opteron/itanium cases. I am a little
> > concerned that this might throw up a bunch of problem cases that we will
> > patching for a while.
>
> Probably so --- but we'd only be breaking new platforms that people are
> starting to use, not old ones that might not be getting tested
> regularly.

Looking at the code, I wonder if we already have folks not using
spinlocks, and not even knowing it. I don't think problem reports will
be limited to new platforms.

> Understand that I'm not dead set against applying this patch for 7.4.
> (On a code-cleanliness point of view I favor it.) What I want is some
> open discussion about the risks and benefits before we decide.

Sure, and I am not pushing the patch. I am just saying it would have
been ideal a few weeks ago --- I am not sure if we are worse off with or
without it.

I just learned from Larry that Unixware defines intel as i386, not
__i386 or __i386__, at least of the native SCO compiler that he uses.

What the code used to do is define NEED_I386_TAS_ASM unconditionally on
some platforms (negating the need to test for a compiler symbol) or test
for each platform compiler symbol (and not test all possible ways it
could be specified), like FreeBSD did. That's why things are so messy.
I am going to test for __cpu, __cpu__, and cpu on non-gcc compiler for
consistency. It is only done in one place in the patch, so that should
be good.

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