Re: [GNUnet-developers] [RFC] util: build with external libatomic

[Christian Grothoff]

Hi Daniel,

The patch looks fine as-is. As for the warning, I don't think it can be
fixed as it seems that libtool looks at the transitive dependency chain.
The best way to fix the warning would seem to be to fix how libatomic is
build on LEDE (as in: not move it, or maybe build in chroot).

Please push the change soon, so we have it for 0.11.0.

Thanks!

Christian

On 2/21/19 8:41 PM, Daniel Golle wrote:
> Recent versions of gcc on some architectures (MIPS, PPC, ...) moved
> atomic functions into a separate library. As we are using atomic
> load/store in util/time.c we may need to link libgnunetutil against
> libatomic for __atomic_load_8 and __atomic_store_8 to be defined.
> 
> Fixes build problem on MIPS:
> ld: ./.libs/libgnunetutil.so: undefined reference to `__atomic_store_8'
> ld: ./.libs/libgnunetutil.so: undefined reference to `__atomic_load_8'
> collect2: error: ld returned 1 exit status
> 
> This patch, however, causes an endless number of
> libtool: relink: warning: 
> `/usr/src/lede/staging_dir/toolchain-mipsel_24kc_gcc-7.4.0_musl/lib/libatomic.la'
>  seems to be moved
> lines printed during build and almost every shared library is linked
> against libatomic in the end (though it would really only be needed
> for libgnunetutil). Apparently libtool's dependency_libs is the problem
> or at least that's where the absolute path of libatomic.la in LIBS
> comes from. I was trying to resolve this autotools mess for 2 hours now
> and didn't manage to *not* have libtool care about libatomic.
> 
> Ideas?
> ---
>  configure.ac         | 7 ++++++-
>  src/util/Makefile.am | 7 +++++++
>  2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 8b93d8d6c..00437f2ef 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -676,6 +677,8 @@ else
>       AC_DEFINE([HAVE_LIBCURL],[1],[Have CURL])
>  fi
>  
> +AC_SEARCH_LIBS(__atomic_load_8, atomic, [have_libatomic=1 
> AC_DEFINE(HAVE_LIBATOMIC,1,[external libatomic])])
> +AM_CONDITIONAL(HAVE_LIBATOMIC, [test "$have_libatomic" = 1])
>  
>  # restore LIBS & CPPFLAGS
>  LIBS=$SAVE_LIBS
> diff --git a/src/util/Makefile.am b/src/util/Makefile.am
> index 0ba06f4bb..5fa6e907e 100644
> --- a/src/util/Makefile.am
> +++ b/src/util/Makefile.am
> @@ -123,6 +123,12 @@ libgnunetutil_la_SOURCES = \
>    speedup.c speedup.h \
>       proc_compat.c
>  
> +if HAVE_LIBATOMIC
> +  LIBATOMIC= -latomic
> +else
> +  LIBATOMIC=
> +endif
> +
>  if HAVE_LIBIDN
>    LIBIDN= -lidn
>  else
> @@ -137,6 +143,7 @@ endif
>  
>  libgnunetutil_la_LIBADD = \
>    $(GCLIBADD) $(WINLIB) \
> +  $(LIBATOMIC) \
>    $(LIBGCRYPT_LIBS) \
>    $(LTLIBICONV) \
>    $(LTLIBINTL) \
>

signature.asc
Description: OpenPGP digital signature