Date: Fri, 9 Nov 2012 18:14:53 -0800 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Dimitry Andric <dim@FreeBSD.org> Cc: freebsd-current@FreeBSD.org Subject: Re: clang and static linking? Message-ID: <20121110021453.GA79662@troutmask.apl.washington.edu> In-Reply-To: <509DA0E4.9060906@FreeBSD.org> References: <20121108231349.GA79485@troutmask.apl.washington.edu> <509D4548.7030806@FreeBSD.org> <20121109182810.GA61338@troutmask.apl.washington.edu> <509D5BC3.9020704@FreeBSD.org> <509D90EC.5040302@FreeBSD.org> <509DA0E4.9060906@FreeBSD.org>
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On Sat, Nov 10, 2012 at 01:33:40AM +0100, Dimitry Andric wrote: > On 2012-11-10 00:25, Dimitry Andric wrote: > ... > > The more difficult way out is to not define any duplicate functions in > > libc.a and libm.a. For the shared libraries, this should not be a > > problem, since the dynamic linker will figure out which of the two > > copies will get precedence. The functions must stay available for > > backwards compatibility reasons anyway. > > > > For static libraries, this compatibility seems to be unnecessary, as > > they will only be used to link new programs. Therefore, it would > > probably be best to remove the whole isnan.o member from libc.a, and > > move all the isnan functions to libm.a instead. > > > > Currently, isnan() is commented out in lib/msun/src/s_isnan.c, maybe we > > can enable it whenever PIC is not defined? Then we could simply skip > > building lib/libc/gen/isnan.c for libc.a. > > More concretely, here is a patch that seems to achieve the above: > - Only define isnan, isnanf, __isnan and __isnanf in libc.so, not in > libc.a and libc_p.a. > - Define isnan in libm.a and libm_p.a, not in libm.so. I don't think > there is a need to define __isnan in the .a files, so I left that out. > Index: lib/libc/gen/isnan.c > =================================================================== > --- lib/libc/gen/isnan.c (revision 242841) > +++ lib/libc/gen/isnan.c (working copy) > @@ -35,6 +35,7 @@ > * binary compat until we can bump libm's major version number. > */ Dimitry, Your patch fixes the initial problem I saw with using gfortran and openmpi. Note, gfortran ignores -fno-builtins and I rarely build C code with -static and -fno-builtins that uses isnan[f]. Unless someone objects, I think your patch is fine. -- Steve
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