Experimental Physics and
Industrial Control System

Michael Davidsaver via Core-talk <core-talk at aps.anl.gov> · Thu, 16 Jul 2020 08:16:00 -0700

> Some linkers do not use -L for indirectly linked libs.

Are you able to elaborate on this?  I know of a similar sounding issue
with some older versions of binutils (I don't know the exact range)
related to -rpath $ORIGIN which I worked around by passing -rpath-link
as well.  I thought that this was limited to use of $ORIGIN though.

https://sourceware.org/bugzilla/show_bug.cgi?id=20535

https://github.com/epics-base/epics-base/blob/7d2e352f6a86eeec8c469917253e5db4af5c9c03/src/tools/makeRPath.py#L69-L72

> using gcc 4.4.2, 4.7.2

which binutils (versions) are involved?   (aka. "ld --version")

On 7/16/20 2:51 AM, Zimoch Dirk (PSI) via Core-talk wrote:
> Hello folks,
> 
> Today I found that some Linux (cross) architectures (using gcc 4.4.2, 4.7.2) require an additional linker flag: -Wl,-rpath-link in addition to -L and -Wl,-rpath. I noticed when compiling asyn.
> It worked for me to change in <BASE>/configure/os/CONFIG.Common.linuxCommon
> PRODDIR_RPATH_LDFLAGS_YES = $(PROD_DEPLIB_DIRS:%=-Wl,-rpath,%)
> to
> PRODDIR_RPATH_LDFLAGS_YES = $(PROD_DEPLIB_DIRS:%=-Wl,-rpath,%) $(PROD_DEPLIB_DIRS:%=-Wl,-rpath-link,%) 
> (Maybe the same should be done for SHRLIBDIR_RPATH_LDFLAGS_YES.)
> 
> Why this? Some linkers do not use -L for indirectly linked libs. E.g. libA.so depends on libB.so and the program is linked with -lA but not with -lB, then some linkers require that B is found in -rpath-link and do not consider -L or -rpath for it. (Maybe the other linkers where it works do not even care about B?)
> 
> In asyn this is the case for test code which links with -lasyn -lCom only. But libasyn.so had been linked with -ldbRecStd -ldbCore -lca -lCom and the linker refuses to use those other libraries from -L<EPICS_BASE_LIBDIR> or -Wl,-rpath<EPICS_BASE_LIBDIR>.
> 
> /opt/eldk-5.3/powerpc-4xx/sysroots/i686-eldk-linux/usr/bin/ppc440e-linux/powerpc-linux-g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE           -m32 -mcpu=440fp -mhard-float --sysroot=/opt/eldk-5.3/powerpc-4xx/sysroots/ppc440e-linux  -DUNIX  -Dlinux  -fno-strict-aliasing    -O3 -g -g   -Wall             -I. -I../O.Common -I. -I. -I.. -I../../../../include/compiler/gcc -I../../../../include/os/Linux -I../../../../include          -I/usr/local/epics/base-7.0.4.1/include/compiler/gcc -I/usr/local/epics/base-7.0.4.1/include/os/Linux -I/usr/local/epics/base-7.0.4.1/include        -c ../asynPortDriverTest.cpp
> /opt/eldk-5.3/powerpc-4xx/sysroots/i686-eldk-linux/usr/bin/ppc440e-linux/powerpc-linux-g++ -o asynPortDriverTest  -L/afs/psi.ch/group/8211/dirk/git/DRV/asyn/lib/eldk53-ppc4xxFP -L/usr/local/epics/base-7.0.4.1/lib/eldk53-ppc4xxFP -Wl,-rpath,/afs/psi.ch/group/8211/dirk/git/DRV/asyn/lib/eldk53-ppc4xxFP -Wl,-rpath,/usr/local/epics/base-7.0.4.1/lib/eldk53-ppc4xxFP       --sysroot=/opt/eldk-5.3/powerpc-4xx/sysroots/ppc440e-linux    -rdynamic         asynPortDriverTest.o    -lasyn -lCom
> /net/gfa-fs-4/export/cross_tools/eldk-5.3/powerpc-4xx/sysroots/i686-eldk-linux/usr/bin/ppc440e-linux/../../libexec/ppc440e-linux/gcc/powerpc-linux/4.7.2/ld: warning: libdbRecStd.so, needed by /afs/psi.ch/group/8211/dirk/git/DRV/asyn/lib/eldk53-ppc4xxFP/libasyn.so, not found (try using -rpath or -rpath-link)
> /net/gfa-fs-4/export/cross_tools/eldk-5.3/powerpc-4xx/sysroots/i686-eldk-linux/usr/bin/ppc440e-linux/../../libexec/ppc440e-linux/gcc/powerpc-linux/4.7.2/ld: warning: libdbCore.so, needed by /afs/psi.ch/group/8211/dirk/git/DRV/asyn/lib/eldk53-ppc4xxFP/libasyn.so, not found (try using -rpath or -rpath-link)
> /net/gfa-fs-4/export/cross_tools/eldk-5.3/powerpc-4xx/sysroots/i686-eldk-linux/usr/bin/ppc440e-linux/../../libexec/ppc440e-linux/gcc/powerpc-linux/4.7.2/ld: warning: libca.so, needed by /afs/psi.ch/group/8211/dirk/git/DRV/asyn/lib/eldk53-ppc4xxFP/libasyn.so, not found (try using -rpath or -rpath-link)
> /afs/psi.ch/group/8211/dirk/git/DRV/asyn/lib/eldk53-ppc4xxFP/libasyn.so: undefined reference to `scanIoRequest' 
> [... more undefined reference errors...]
> 
> Even though the warning suggests using -rpath or -rpath-link, only -rpath-link actually does the job.
> 
> Is there any (old) Linux architecture where adding -rpath-link may cause problems?
> 
> Dirk
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System