what to do with missing libgcc_s.a

c compilation flags buildroot libgcc
drahnr picture drahnr · Sep 14, 2013 · Viewed 13.4k times · Source

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

Answer

ash picture ash · Sep 14, 2013

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"

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