Back in February I reported ( http://www.open-mpi.org/community/lists/devel/2015/02/17073.php) that when building master on Linux with the Solaris Studio compilers and -m32 I saw the following:
/bin/sh ../../../libtool --tag=CC --mode=link cc -m32 -g -mt -export-dynamic -o opal_wrapper opal_wrapper.o ../../../opal/ libopen-pal.la -lrt -lm -lutil -lrt -lm -lutil libtool: link: cc -m32 -g -mt -o .libs/opal_wrapper opal_wrapper.o -Wl,--export-dynamic ../../../opal/.libs/libopen-pal.so -ldl -lrt -lm -lutil -mt -Wl,-rpath -Wl,/scratch/phargrov/OMPI/openmpi-master-linux-x86_64-ss12u4-m32/INST/lib ../../../opal/.libs/libopen-pal.so: undefined reference to `ebx' Where obviously 'ebx' should be a register, not a symbol. Nobody got back to me on that, but I figured it out this morning. The 2-line patch below fixed this issue for me. It looks like the gcc asm syntax for multiple assembler dialects (search for "dialects" in https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html) is not supported by the Studio compilers. Since there doesn't appear to be any real effort to support Intel asm syntax (vs the ATT syntax used by gas) elsewhere in Open MPI, it is kind of pointless to do it just in this one header. So, I believe that the "{l}" on the changed lines can/should also be changed to bare "l". On a related note: As of gcc-5.1 (released in April), ebx is now scheduled as an other register and not reserved to be the GOT pointer. So, the xchgl %%ebx, %1 could (I think) now become xchgl %%ebx,%%ebx which is not going to have the desired effect of preserving %ebx across the cpuid instruction. However the problem only occurs if "b" is a member of the "r" class, which I have not verified. *IF* the problem can occur, then one fix would be to change "=r" to something like "=SD". -Paul --- opal/include/opal/sys/ia32/timer.h.orig 2015-07-01 08:12:59.357980816 -0700 +++ opal/include/opal/sys/ia32/timer.h 2015-07-01 07:59:36.452918286 -0700 @@ -35,9 +35,9 @@ int tmp; __asm__ __volatile__( - "xchg{l} {%%}ebx, %1\n" + "xchg{l} %%ebx, %1\n" "cpuid\n" - "xchg{l} {%%}ebx, %1\n" + "xchg{l} %%ebx, %1\n" "rdtsc\n" : "=A"(ret), "=r"(tmp) :: "ecx"); -- Paul H. Hargrove phhargr...@lbl.gov Computer Languages & Systems Software (CLaSS) Group Computer Science Department Tel: +1-510-495-2352 Lawrence Berkeley National Laboratory Fax: +1-510-486-6900
