Possible problem with LT 2.2

[Jeff Squyres]

Greetings.

I noticed an odd problem earlier today when building the Open MPI  
development trunk from subversion on a Linux RHEL4U4 system (x86_64)  
with gcc and LT 2.2, AM 1.10, and AC 2.61.

A little background:

- Open MPI is based on plugins.  We use libltdl to lt_dlopen() various  
types of plugins.  One type of plugin is called "btl" (byte transfer  
layer), which loosely translates to what kind of network you're using.

- The default Open MPI build is to create shared libraries (libmpi.so)  
and build the plugins as DSOs (e.g., mca_btl_tcp.so).  However, if  
OMPI's configure script detects "--enable-static --disable-shared", it  
will instead build all the plugins as convenience libraries and  
include them in libmpi.a.

- The default build is working fine.  But when I manually configure  
with --enable-static --disable shared, I'm getting a missing symbols  
error when trying to link an executable that links against libmpi.a.

- The missing symbols are originating from the SCTP BTL plugin.  The  
SCTP plugin has a dependency against the sctp library (I have both  
libsctp.so and libsctp.a on my system).  When mca_btl_sctp.la is  
created, it contains the following line:

    dependency_libs=' /usr/lib64/libsctp.la -lnsl -lutil -lm'

- mca_btl_sctp.la is then sucked into libmpi.la via libmpi_la_LIBADD.   
However, its dependency_libs value seems to be missing any mention of  
the libsctp dependency:

  dependency_libs=' -libverbs -lrt /users/jsquyres/svn/ompi2/orte/ 
libopen-rte.la users/jsquyres/svn/ompi2/opal/libopen-pal.la -lnuma - 
ldl -lnsl -lutil -lm'

(all the other entries in there look good)

- It seems to directly follow that when I try to link an executable  
against libmpi.a (more specifically, libmpi.la is in the executable's  
LDADD), it can't find some symbols that exist in libsctp.a and the  
link fails.

- Here's the libtool link command that generates mca_btl_sctp.la:

libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I../../../../opal/include - 
I../../../../orte/include -I../../../../ompi/include -I../../../../ 
opal/mca/paffinity/linux/plpa/src/libplpa -I../../../.. -g -Wall - 
Wundef -Wno-long-long -Wsign-compare -Wmissing-prototypes -Wstrict- 
prototypes -Wcomment -pedantic -Werror-implicit-function-declaration - 
finline-functions -fno-strict-aliasing -pthread -MT btl_sctp_utils.lo - 
MD -MP -MF .deps/btl_sctp_utils.Tpo -c btl_sctp_utils.c  -fPIC -DPIC - 
o .libs/btl_sctp_utils.o
/bin/sh ../../../../libtool --tag=CC   --mode=link gcc  -g -Wall - 
Wundef -Wno-long-long -Wsign-compare -Wmissing-prototypes -Wstrict- 
prototypes -Wcomment -pedantic -Werror-implicit-function-declaration - 
finline-functions -fno-strict-aliasing -pthread -module -avoid- 
version  -export-dynamic   -o mca_btl_sctp.la -rpath /home/jsquyres/ 
bogus/lib/openmpi btl_sctp.lo btl_sctp_component.lo  
btl_sctp_endpoint.lo btl_sctp_frag.lo btl_sctp_proc.lo  
btl_sctp_recv_handler.lo btl_sctp_utils.lo -lsctp  -lnsl -lutil  -lm
libtool: link: gcc -shared  .libs/btl_sctp.o .libs/ 
btl_sctp_component.o .libs/btl_sctp_endpoint.o .libs/ 
btl_sctp_frag.o .libs/btl_sctp_proc.o .libs/ 
btl_sctp_recv_handler.o .libs/btl_sctp_utils.o   -Wl,-rpath -Wl,/usr/ 
lib64 -Wl,-rpath -Wl,/usr/lib64 /usr/lib64/libsctp.so -lnsl -lutil - 
lm  -pthread   -pthread -Wl,-soname -Wl,mca_btl_sctp.so -o .libs/ 
mca_btl_sctp.so
libtool: link: creating mca_btl_sctp.la
libtool: link: ( cd ".libs" && rm -f "mca_btl_sctp.la" && ln -s "../ 
mca_btl_sctp.la" "mca_btl_sctp.la" )

- Per request from Ralf W., I ran the libtool command manually, but  
with --debug as the first argument.  It's unfortunately not much more  
information:

% /bin/sh --debug ../../../../libtool --tag=CC --mode=link gcc -g - 
Wall -Wundef -Wno-long-long -Wsign-compare -Wmissing-prototypes - 
Wstrict-prototypes -Wcomment -pedantic -Werror-implicit-function- 
declaration -finline-functions -fno-strict-aliasing -pthread -module - 
avoid-version -export-dynamic -o mca_btl_sctp.la -rpath /home/jsquyres/ 
bogus/lib/openmpi btl_sctp.lo btl_sctp_component.lo  
btl_sctp_endpoint.lo btl_sctp_frag.lo btl_sctp_proc.lo  
btl_sctp_recv_handler.lo btl_sctp_utils.lo -lsctp -lnsl -lutil -lm | &  
tee lt-debug.out
libtool: link: rm -fr  .libs/mca_btl_sctp.a .libs/ 
mca_btl_sctp.la .libs/mca_btl_sctp.lai
libtool: link: ar cru .libs/mca_btl_sctp.a  btl_sctp.o  
btl_sctp_component.o btl_sctp_endpoint.o btl_sctp_frag.o  
btl_sctp_proc.o btl_sctp_recv_handler.o btl_sctp_utils.o
libtool: link: ranlib .libs/mca_btl_sctp.a
libtool: link: ( cd ".libs" && rm -f "mca_btl_sctp.la" && ln -s "../ 
mca_btl_sctp.la" "mca_btl_sctp.la" )

- The command to create libmpi.a is extremely long, so I included it  
in an attachment.  More specifically, I have attached the following:
  - Full output from configure (I doubt it will help, but more  
information is better than less; you can see the checks for libsctp in  
the middle)
  - The resulting config.log file
  - Full output from make (the building of mca_btl_sctp.la is buried  
in the middle)
  - Output from ./libtool --config
  - Output from ./libtool --config --tag=CC

Any ideas what the problem could be here?

Please let me know if I can provide any further information.  Thanks!

--
Jeff Squyres
Cisco Systems

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