what to do with missing libgcc_s.a

Question

cross compiling a library with buildroot using the external toolchain alias code sourcery lite 2011 resulting in

output/host/opt/ext-toolchain/bin/../lib/gcc/arm-none-linux-gnueabi/4.6.1/../../../../arm-none-linux-gnueabi/bin/ld: cannot find -lgcc_s
collect2: ld returned 1 exit status

due to an obviously missing libgcc_s.a

# find . -iname "libgcc*"        
./output/host/usr/arm-buildroot-linux-gnueabi/sysroot/lib/libgcc_s.so
./output/host/usr/arm-buildroot-linux-gnueabi/sysroot/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/armv4t/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/armv4t/lib/libgcc_s.so
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/thumb2/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/thumb2/lib/libgcc_s.so
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/lib/libgcc_s.so
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/armv4t/libgcc.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/armv4t/libgcc_eh.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/plugin/libgcc
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/thumb2/libgcc.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/thumb2/libgcc_eh.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/libgcc.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/libgcc_eh.a

Is there any way to circumvent this issue but still linking statically? Is there a CLFAGS or LDFLAGS option that does link everything statically except libgcc_s?

Stuff tried so far (beyond reading applicable parts of ld and gcc man pages):

CFLAGS="-static -static-libgcc"
CFLAGS="-static -shared-libgcc"
CFLAGS="-static -static-libgcc -Wl,-Bstatic"
CFLAGS="-static -shared-libgcc -Wl,-Bstatic"

---

After adding -Wl,-lgcc_s,-Bstatic I get a huge load of undefined/unknown symbols... (-Bshared is not a valid options says ld)

/home/bernhard/buildroot-2013.08/output/target/usr/lib/libgio-2.0.a(libgio_2_0_la-glocalfileinfo.o): In function `_g_local_file_info_get':
glocalfileinfo.c:(.text+0x2d90): warning: Using 'getgrgid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libgio-2.0.a(libgio_2_0_la-glocalvfs.o): In function `g_local_vfs_parse_name':
glocalvfs.c:(.text+0x174): warning: Using 'getpwnam' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libglib-2.0.a(libglib_2_0_la-gutils.o): In function `g_get_user_database_entry':
gutils.c:(.text+0x254): warning: Using 'getpwuid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0x24c): warning: Using 'setpwent' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0x25c): warning: Using 'endpwent' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0xa0): warning: Using 'getpwnam_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0xe0): warning: Using 'getpwuid_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libgio-2.0.a(libgio_2_0_la-gnetworkaddress.o): In function `g_network_address_parse_sockaddr':
gnetworkaddress.c:(.text+0x1ac): warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
<<<< SNIP >>>>
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libxml2.a(xmlschemastypes.o): In function `xmlSchemaGetCanonValue':
xmlschemastypes.c:(.text+0x7680): undefined reference to `trunc'
xmlschemastypes.c:(.text+0x76bc): undefined reference to `trunc'
xmlschemastypes.c:(.text+0x7710): undefined reference to `floor'
xmlschemastypes.c:(.text+0x7760): undefined reference to `floor'
collect2: ld returned 1 exit status

Unclench

#7812462 – Percolate

Answer 1

It may be possible to eliminate the use of libgcc_s.a with flags that prevent gcc from using internal built-in functions (such as it's built-in memcpy), but you are probably best served by locating and using it.

Looks like this option should prevent the use of built-ins -fno-builtin. See here for more details: http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html

Linking with the Shared libgcc_s.so

If the libgcc_s.a is missing, or it's desirable to use a shared libgcc_s with an otherwise static executable, this should do the job:

CFLAGS="-static -Wl,-Bdynamic,-lgcc_s,-Bstatic"

Governance

the above is the output of find looking for the libgcc_s in the install path of the cross compiler (yes it is installed within the buildroot directory which is the current working directory .) and thus it simply seems to not exist... – Unclench

hmm, somehow it's skipping that one. I would try gcc -v or strace to verify it's trying to use that specific path then. – Governance

ah, looking carefully at the find output - there is no libgccc_s.a in there, so statically linking won't work. You could try linking it dynamically - I'll update the answer to show how. – Governance

Sorry don't get it, the libgcc_s.a simply does not exist as show in the find results. There are plenty other libgcc.a libgcc_eh.a but not a single instance of libgcc.a. I checked the paths anyways and they seem to be totally fine (Updated question) – Unclench

The update in the answer should cover it. It stinks that the gcc_s.a is missing - if you want a truly static executable, you'll either need that lib, or to use the -fno-builtin to exclude its use (if that's sufficient). – Governance

Suboptimal - I am glued to that toolchain... and -fno-builtin seems to fail/be not sufficient but I am currently my builtscript has some other issues I have to get rid of first - will comment back on as soon as it works/I am sure not working – Unclench

I understand. Perhaps you can go back to the source of the toolchain and try to get the libgcc_s.a from there. It might be possible to grab one from somewhere else and use it, but that could lead to painful bugs. It is possible to stop using libgcc_s.a, but it's been a long time since doing it. – Governance

I am still a cross compiling novice so I'd rather not burn my hands that bad (also see updated question) – Unclench

Also -Bshared does not seem to be supported, but it rather being the default so I tried -static -Wl,-lgcc_s,-Bstatic instead which should yield the same – Unclench

Ah, looks like it should be -Bdynamic not shared. – Governance

output does not change with additional -Bdynamic – Unclench

guess that is due to ordering of lib includes - anyways initial problem solved – Unclench

the first time a lib is pulled-in by it's placement on the command-line determines how it's included. If static is set, it must be static, if dynamic it can be either dynamic or static. So, -Bstatic -lx -Bdynamic -ly takes x as static only, and y as either. Typically, to force one lib to be static, we do -Bstatic -lx -Bdynamic so it can be added with other arguments before and after without breaking anything. – Governance