I'm running into an issue after upgrading gcc from 4.1.1 to 4.7.2. The problem is that the ld --as-needed flag is not pruning libraries that are not required if enough libraries with inter dependencies are listed.
For example, if I build a simple program that doesn't need any special libraries, but includes them on the build line, as such
gcc -m32 test.c -Wl,--as-needed -L/usr/local/lib -lrt -lprojcommon -lproj -lrte -o test
then it builds fine and the --as-needed flag does it's job pruning out all of the listed libs that are not needed.
ldd test
linux-gate.so.1 => (0x00bfc000)
libc.so.6 => /lib/libc.so.6 (0x001ac000)
/lib/ld-linux.so.2 (0x0018a000
However, if I add one more library (in this case crypto), then the build fails with undefined reference errors.
gcc -m32 test.c -Wl,--as-needed -L/usr/local/lib -lcrypto -lrt -lprojcommon -lproj -lrte -o test
/usr/local/lib/librte.so: error: undefined reference to 'tla_decap_data'
/usr/local/lib/librte.so: error: undefined reference to 'do_db'
collect2: error: ld returned 1 exit status
This exact same build worked with 4.1.1, but started failing with 4.7.2.
This is part of a general build infra and libraries included on the build line are generic and expected to be pruned via --as-needed. I could fix this with --allow-shlib-undefined, but I'd prefer to find real unresolved symbols at build time. If I do set --allow-shlib-undefined, then I end up with the same set of required libs as the build that worked.
Any insight would be appreciated.
Related
I am working on a project which eventually requires me to link my code against my customized version of libc, libstdc++ and libgcc. Now I am learning what libraries are linked by default.
I tried to compile my project code with -nolibc and manually provide the needed libraries in the argument list.
g++ -fuse-ld=gold -O2 -o main -static -nolibc main.cpp -lgcc -lm -lc
I got the following error, showing that I missed some libraries.
/usr/lib/gcc/x86_64-linux-gnu/9/libgcc_eh.a(unwind-dw2-fde-dip.o):function _Unwind_Find_FDE: error: undefined reference to 'dl_iterate_phdr'
Which library is missing here?
I am trying to cross compile my application for a arm based system.
I have 2 libraries compiled in the following way:
$ gcc -shared --sysroot=$DIR_PATH -o $LIBPATH/libfoo.so foo.o
$ gcc -shared --sysroot=$DIR_PATH -o $LIBPATH/libbar.so bar.o
A third library is compiled:
gcc -shared -o $LIBPATH/libfoobar.so --sysroot=$DIR_PATH -L$LIBPATH -Wl,rpath=$RUN_TIME_PATH foobar.o -lfoo -lbar
Then finally I compile a binary:
gcc -o app --sysroot=$DIR_PATH -L$LIBPATH -Wl,rpath=$RUN_TIME_PATH app.o -lfoobar
However when compiling app I get
warning: libfoo.so, needed by libfoobar.so, not found (try using -rpath or -rpath-link)
I believe you need to use -Wl,-rpath-link=$LIBPATH to tell the linker where to look to resolve runtime library references during the link operation.
More info can be found in the ld documentation: https://sourceware.org/binutils/docs-2.37/ld/Options.html
I'm trying to build clang, with all library static linked in. So that I can run it on CentOS 6 with ancient GCC 4.4 version.
At first, I think adding the option -static by turning on LLVM_BUILD_STATIC is enough. But in the link stage, it errors out.
dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/usr/lib/../lib64/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie
So, I add -fPIE -Wl,-pie to CMAKE_CXX_FLAGS, and it says
-- Performing Test HAVE_CXX_ATOMICS_WITH_LIB
-- Performing Test HAVE_CXX_ATOMICS_WITH_LIB - Failed
CMake Error at cmake/modules/CheckAtomic.cmake:49 (message):
Host compiler must support std::atomic!
Call Stack (most recent call first):
cmake/config-ix.cmake:307 (include)
CMakeLists.txt:590 (include)
I checked the cmake/modules/CheckAtomic.cmake file, It compiles the following code
#include <atomic>
std::atomic<float> x(0.0f);
int main() { return (float)x; }
with command
/home/hailin/gcc-4.8.3-boost-1.55/rtf/bin/g++ -fPIE -Wl,-pie -DHAVE_CXX_ATOMICS_WITHOUT_LIB -std=c++11 -static -lm
/home/hailin/gcc-4.8.3-boost-1.55/rtf/bin/g++ -fPIE -Wl,-pie -DHAVE_CXX_ATOMICS_WITH_LIB -std=c++11 -static -lm -latomic
The command with option -Wl,-pie reproduce the same error.
It seems like a dead end. Is there any conflict between -shared and -fPIE -Wl,-pie ?
Old question, but in case someone else hits it: apparently you need to pass -pie to the compiler driver (gcc/g++), not just the linker (-Wl,-pie). Some startup object files differ for PIE (e.g. Scrt1.o instead of crt1.o) and these are passed by the driver to the linker, so the driver needs to know that you're making a PIE.
I'm trying to build the newest gcc on my redhat box. I've downloaded and built the latest gmp, mpfr and mpc, per requirements and installed them in my local libraries. From the config.log file I have the following given below. Clearly the system version of mpfr is broken, and I want the configure to ignore it. I have set LIBRARY_PATH and LD_LIBRARY_PATH to point to my local installation /u/victor/lib. Since I'm running a configure script, it's not reasonable for me to try to change command line options for gcc. How do I fix this?
gcc -o conftest -g -O2 conftest.c -L/u/victor/lib -L/u/victor/lib -L/u/victor/lib -lmpc -lmpfr -lgmp >&5
/usr/bin/ld: warning: libmpfr.so.1, needed by /u/victor/lib/libmpc.so, may conflict with libmpfr.so.4
/usr/bin/ld: __gmpfr_cache_const_euler: TLS definition in /u/victor/lib/libmpfr.so section .tdata mismatches non-TLS definition in /usr/lib64/libmpfr.so.1 section .data
What's even more confusing, is that when I compile conftest.c and then
gcc -o conftest conftest.o -lmpc -lmpfr -lgmp
with export LD_LIBRARY_PATH=/u/victor/lib it gives the errors below. I've check libmfpr.so with nm and the three "undefined" symbols are there.
/u/victor/lib/libmpc.so: undefined reference to `mpfr_min_prec'
/u/victor/lib/libmpc.so: undefined reference to `mpfr_set_zero'
/u/victor/lib/libmpc.so: undefined reference to `mpfr_get_z_2exp'
I am trying to build a library that only has static references to libgfortran (and preferably libgcc also).
However, if I use the linker flags
-static -lgfortran -static-libgfortran -static-libgcc
on OS X I get
ld: library not found for -lcrt0.o
collect2: error: ld returned 1 exit status
and if I try to use
-shared -lgfortran -static-libgfortran
I get
Undefined symbols for architecture x86_64:
"_quadmath_snprintf", referenced from:
_write_float in libgfortran.a(write.o)
"_strtoflt128", referenced from:
__gfortrani_convert_real in libgfortran.a(read.o)
__gfortrani_convert_infnan in libgfortran.a(read.o)
and everything compiles fine (but has a dynamic link to libgfortran and libgcc) if I use -dynamiclib -lgfortran.
It would appear that gcc is not build statically on OS X.
How do I build my library so that end-users don't need to have gfortran or gcc installed?
I'm using the macports version of gcc but I'm prepared to use another distributor of gfortran/gcc if it allows me to do this.
-dynamiclib -lgfortran -static-libgfortran \
/opt/local/lib/gcc47/libquadmath.a -static-libgcc
seems to do the trick!
The bizarre thing was figuring out that I needed to add a full path to the libquadmath.a, which feels like a bug with gcc/gfortran to be honest.