Date: Wed, 6 Nov 2013 08:55:16 +0100 From: Dimitry Andric <dim@FreeBSD.org> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, Luigi Rizzo <rizzo@iet.unipi.it> Subject: Re: svn commit: r257691 - head/gnu/lib/libgcc Message-ID: <38BB8918-1311-4C23-8992-43A272250F05@FreeBSD.org> In-Reply-To: <20131106144724.I3234@besplex.bde.org> References: <201311050737.rA57bZkq059529@svn.freebsd.org> <20131105154519.GD65141@onelab2.iet.unipi.it> <20131106144724.I3234@besplex.bde.org>
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On 06 Nov 2013, at 05:30, Bruce Evans <brde@optusnet.com.au> wrote:
> On Tue, 5 Nov 2013, Luigi Rizzo wrote:
>> On Tue, Nov 05, 2013 at 07:37:35AM +0000, Dimitry Andric wrote:
>>> Log:
>>> Fix libgcc build with gcc after r257645, by using =
-Wno-static-in-inline
>>> for clang only.
> This still just breaks the warning. See my previous reply. (For gcc,
> it is unclear if the missing warning is due too fewer warnings by
> default or if it is because gcc's default for plain inline is =
different
> from clang's so that the code is correct for gcc.).
First of all, gcc only emits this warning when using -pedantic, see
contrib/gcc/c-typeck.c, around line 2123. However, our copy of gcc also
ships with a faulty C99 test in contrib/gcclibs/include/ansidecl.h,
which has (around line 176):
/* inline requires special treatment; it's in C99, and GCC >=3D2.7 =
supports =
=20
it too, but it's not in C89. */ =
=
=20
#undef inline =
=
=20
#if __STDC_VERSION__ > 199901L =
=
=20
/* it's a keyword */ =
=
=20
#else =
=
=20
# if GCC_VERSION >=3D 2007 =
=
=20
# define inline __inline__ /* __inline__ prevents -pedantic warnings =
*/ =
=20
# else =
=
=20
# define inline /* nothing */ =
=
=20
# endif =
=
=20
#endif =
=
=20
Upstream gcc fixed this here:
=
http://gcc.gnu.org/viewcvs/gcc/trunk/include/ansidecl.h?r1=3D155654&r2=3D1=
55653&pathrev=3D155654
>> I wonder if it is worthwhile adding to the default rules some
>> compiler-specific CFLAGS, say CFLAGS_CLANG and CFLAGS_GCC
>>=20
>> (there is only a handful of cases now so maybe it is overkill,
>> and it harms readability; on the other hand, the Makefiles
>> already make a lot of assumptions on variable names)
> No, that would further simplify breaking warnings instead of fixing =
the
> bugs exposed by warnings. The code should be portable so that it =
works
> with any compiler. That is just not so easy for contrib'ed code =
unless
> the vendor made it portable.
I agree for this particular case, but there are other places in the tree
where we must pass either clang-specific or gcc-specific flags.
Introducing the variables Luigi suggested makes those Makefiles a little
less ugly, at least.
> I checked that libgcc is compiled by default with -std=3Dgnu99. This
> is just the default from bsd.sys.mk. It is obviously wrong for =
libgcc,
> since the plain inlines in it require gnu89.
Yes, I agree. This can be fixed in libgcc's Makefile, but unfortunately
clang will still emit the warning.
> gnu99 gives consistenly
> broken C99 semantic for both gcc and clang. Only clang warned about
> this, and the warning has been broken.
Indeed, it always emits the warning, even for -std=3Dgnu89, and even =
when
__inline__ is explicitly used. This could probably be considered a bug,
but I think upstream has meant this as a general warning towards making
code C99-compliant. Is it too hard to make a static variable
non-static? :)
-Dimitry
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