Package: libtool Version: 2.4.2-1.7 Severity: important Forwarded: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17750
hi,
this copy of a upstream bug report. As Debian now has gcc-4.9 available
this should be fixed for jessie regardless of upstreams reaction time.
gcc-4.9 now supports cilkplus with the -fcilkplus flag.
libtool strips this flag from LDFLAGS leading to an wrongly linked library.
To reproduce choose a random libtool based project (e.g. libmatheval)
and add this function in a random file (e.g. lib/node.c):
#include <cilk/cilk.h>
int n(char * a)
{
a = cilk_spawn atoi(a);
return a;
}
then configure build with:
./configure CFLAGS="-fcilkplus" LDFLAGS="-fcilkplus" CC=gcc-4.9
during linking -fcilkplus is not used and the library is underlinked:
./libmatheval-1.1.11+dfsg# ldd -r ./lib/.libs/libmatheval.so
linux-vdso.so.1 (0x00007fffccdc4000)
/usr/lib/libeatmydata/libeatmydata.so (0x00007eff50cfd000)
/usr/lib/cowdancer/libcowdancer.so (0x00007eff50af9000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007eff507f3000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007eff5044a000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007eff50246000)
/lib64/ld-linux-x86-64.so.2 (0x00007eff5110f000)
undefined symbol: __cilkrts_rethrow (./lib/.libs/libmatheval.so)
undefined symbol: __cilkrts_enter_frame_1 (./lib/.libs/libmatheval.so)
undefined symbol: __cilkrts_save_fp_ctrl_state (./lib/.libs/libmatheval.so)
undefined symbol: __cilkrts_sync (./lib/.libs/libmatheval.so)
undefined symbol: __cilkrts_leave_frame (./lib/.libs/libmatheval.so)
undefined symbol: __cilkrts_enter_frame_fast_1 (./lib/.libs/libmatheval.so)
it needs to be linked against libcilkrts.so.5
This is identical to libtools stripping of fopenmp and the fix is the
same, add -fcilkplus to the whitelist.
Similar the new -fsanitizer= flags are stripped from LDFLAGS, they
should probably be added too.
Cheers,
Julian Taylor
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