Re: Static Build on armv7

[Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>]

On 3/31/22 01:50, Florian Feldbauer wrote:
> ...
> > $ cat configure/os/CONFIG.linux-arm.linux-arm
> > # CONFIG.linux-arm.linux-arm
> > #
> > # Definitions for native linux-arm builds
> > # Sites may override these definitions in CONFIG_SITE.linux-arm.linux-arm
> > #-------------------------------------------------------
> >
> > # Include common gnu compiler definitions
> > include $(CONFIG)/CONFIG.gnuCommon
> > $ cat configure/os/CONFIG.linux-x86.linux-x86
> > #  CONFIG.linux-x86.linux-x86
> > #
> > # Definitions for linux-x86 host - linux-x86 target builds
> > # Sites may override these definitions in CONFIG_SITE.linux-x86.linux-x86
> > #-------------------------------------------------------
> >
> > # Include common gnu compiler definitions
> > include $(CONFIG)/CONFIG.gnuCommon
> >
> > STATIC_LDFLAGS_YES= -Wl,-Bstatic
> > STATIC_LDFLAGS_NO=
> > STATIC_LDLIBS_YES= -Wl,-Bdynamic
> > STATIC_LDLIBS_NO=
>
>
> Adding those 4 last rows from CONFIG_SITE.linux-x86.linux-x86 to CONFIG_SITE.linux-arm.linux-arm solved my issue.
> Now static build also works on armv7.

I think you are correct that passing both '-static' and '-Wl,-Bdynamic'
is a contradiction, which GCC unfortunately does not flag as an error.

Do you want to formulate this change as a pull request?

https://github.com/epics-base/epics-base/


I can't see exactly where, but "/lib/ld.so.1" must be used as a default
when no "-dynamic-linker ..." is passed to "ld".  The valid values
for ARM are given here:

https://github.com/gcc-mirror/gcc/blob/0abc1cbad1687a887d754917927b6023e4dba3ce/gcc/config/arm/linux-eabi.h#L59-L65

fyi. these names actually appears in GCC's generated spec file(s), where
it can presumably be overwritten, if you understand spec files better than
I do...

https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html

> gcc -dumpspecs|grep dynamic-linker

As I understand it, on amd64 it looks like all of the "-dynamic-linker ..."
are wrapped in a conditional "%{!static: ...}".  So '-static' prevents
any from being passed to "ld".


> Cheers,
> Florian
>
>
> > Alternately, you could path Base to remove references to "-Wl,-Bdynamic",
> > which would result in a fully static executable (with the limitations
> > which this implies).
> >
> > > /usr/bin/g++ -o antelope -static -L/epics/base/lib/linux-arm -Wl,-rpath,/epics/base/lib/linux-arm          -rdynamic closure.o error.o lalr.o lr0.o antelope.o mkpar.o output.o reader.o skeleton.o symtab.o verbose.o warshall.o -Wl,-Bdynamic  -lpthread   -lreadline -lm -lrt -ldl -lgcc
> >
> > However, you may later encounter strange linker errors and/or crashes
> > if object code from different, somewhat incompatible, toolchains are
> > being linked together.  So I would encourage you to investigate the
> > toolchain(s) first.
> >
> >
> > > Cheers,
> > > Florian
> > >
> > >
> > > Am 30.03.2022 um 17:47 schrieb Michael Davidsaver:
> > > > On 3/30/22 07:15, Florian Feldbauer via Tech-talk wrote:
> > > > > Hey all,
> > > > >
> > > > > we use docker images to easily deploy our IOCs for our detector control system.
> > > > > The images are build for amd64, arm64/aarch64 and armv7.
> > > > >
> > > > > To reduce the size of those images, I recently switched from dynamic to static linking by adding the line
> > > > >  >      && echo "STATIC_BUILD=YES" >> configure/CONFIG_SITE.local \
> > > > > to our Dockerfile.
> > > > >
> > > > > When compiling base7 for amd64 and aarch64 this is working just fine, but I get an error on arm/v7:
> > > > >
> > > > > > #0 189.7 Installing created executable /epics/base/bin/linux-arm/antelope
> > > > > > #0 190.1 /epics/base/bin/linux-arm/antelope -bparse -l -d ../flex/parse.y
> > > > > > #0 190.1 /usr/lib/ld.so.1: No such file or directory
> > > > > > #0 198.7 Expanding ../libComVersion.h@ to ../O.Common/libComVersion.h
> > > > >
> > > > > I investigated the issue a bit closer and found the following:
> > > > >
> > > > > > root@195e454a8580:/epics/src/base# ldd /epics/base/bin/linux-arm/antelope
> > > > > >   linux-vdso.so.1 (0x7ef10000)
> > > > > >   libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0x76e71000)
> > > > > >   /usr/lib/ld.so.1 => /lib/ld-linux-armhf.so.3 (0x76f70000)
> > > >
> > > > It looks like "STATIC_BUILD=YES" was ignored.
> > > >
> > > > > > root@195e454a8580:/epics/src/base# ls /usr/lib/ld.so.1
> > > > > > ls: cannot access '/usr/lib/ld.so.1': No such file or directory
> > > > >
> > > > > For some reason antelope gets linked against /usr/lib/ld.so.1 on armv7 but this file does not exist.
> > > > > Does anyone know what causes this issue?
> > > >
> > > > It would help if you could attach, or post somewhat, the complete
> > > > output of a clean 'make'.
> > > >
> > > > Also the output of:
> > > >
> > > > > readelf -aW /epics/base/bin/linux-arm/antelope
> > > >
> > > >
> > > >
> > > > > Cheers,
> > > > > Florian