clang and static linking?

Dimitry Andric dim at
Sat Nov 10 00:33:40 UTC 2012

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, not in
   libc.a and libc_p.a.
- Define isnan in libm.a and libm_p.a, not in  I don't think
   there is a need to define __isnan in the .a files, so I left that out.
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