[Pixman] pixman on iOS

[Siarhei Siamashka]

On Fri, 02 Nov 2012 01:40:01 +0100
sandmann at cs.au.dk (Søren Sandmann) wrote:

> Siarhei Siamashka <siarhei.siamashka at gmail.com> writes:
> 
> >> > I would suggest to just change the order of checks for
> >> > __declspec(thread) and __thread in configure.ac
> >> 
> >> We should maybe try using -Werror=ignored-attributes in the test, or
> >> just prefer the first one.
> >
> > Using -Werror=ignored-attributes will not help because clang-3.1 (and
> > maybe older versions too) just silently ignores __declspec(thread).
> > This non-working TLS problem could have been detected by the pixman test
> > suite if clang had OpenMP support. In any case, I was just lucky to
> > notice the fresh warning when doing preemptive testing for the current
> > clang svn (just to be sure that pixman would not need any ugly compiler
> > bug workarounds for the upcoming clang-3.2).
> >
> > Regarding your original patch, how does iOS behave when somebody
> > tries to use __thread keyword? Does it fail compilation?
> 
> If nobody knows the answer to this, let's just change the order of the
> checks as you suggested. We can't support iOS unless someone is willing
> to maintain it.

Now it appears that this bug also affects mingw-w64, not just clang:
    https://bugs.freedesktop.org/show_bug.cgi?id=57591

I have sent a patch to change the order of checks, but another option
to evaluate is to revert a069da6c66da407cc52e1e92321d69c68fd6beb5.

Jeremy, it might look like I'm picking on you, but it would really help
to get a confirmation that a069da6c66da407cc52e1e92321d69c68fd6beb5
actually fixed some real problem on iOS. The commit message was a bit
vague. Shit happens, I guess nobody here could have predicted that
__declspec generally has such a weird behavior in modern compilers and
everyone had time to review your patch before it got pushed. So it
is not like you are the one to blame.

-- 
Best regards,
Siarhei Siamashka