Ошибки компоновщика при компиляции директивы OpenMP `target` с использованием Clang 6 (trunk) с целью nvptx

Question

Ошибки компоновщика при компиляции директивы OpenMP `target` с использованием Clang 6 (trunk) с целью nvptx

Я хочу запустить код OpenMP4+ на моем графическом процессоре Nvidia, используя LLVM/Clang. Я загрузил и скомпилировал библиотеки llvm / clang / omp из транка, следуя инструкциям, найденным здесь: https://clang.llvm.org/get_started.html и здесь: https://openmp.llvm.org/. Я не собирал Compiler-RT и libcxx, но я не думаю, что это что-то меняет.

Моя команда CMake была такой: cmake -G "Unix Makefiles" ../llvm -DCMAKE_BUILD_TYPE=Release -DOPENMP_ENABLE_LIBOMPTARGET=ON

Я написал очень простую программу с одним OpenMP target директива:

int main(void)
{
    #pragma omp target
    {
    }
    return 0;
}

И я собираю это с этим:/home/user/opt/llvm/bin/clang++ -v main.cpp -fopenmp -lomptarget -fopenmp-targets=nvptx64-nvidia-cuda --cuda-path=/home/user/opt/pgi/linux86-64/2017/cuda/8.0

Если вы спросите: да, я не установил свои пути для компилятора, но я убедился, что мой LD_LIBRARY_PATH точки, где libomptarget расположен.

И вот вывод / ошибка, которую я получаю после выполнения вышеупомянутой команды (последние ~10 строк показывают ошибку):

<If this is too much information, just go to the last 10 lines to see the error>
clang version 6.0.0 (trunk 312875)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/user/opt/llvm/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6.4.0
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/7.2.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.2.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.2.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
Found CUDA installation: /home/user/opt/pgi/linux86-64/2017/cuda/8.0, version 7.0
 "/home/user/opt/llvm/bin/clang-6.0" -cc1 -triple x86_64-unknown-linux-gnu -emit-llvm-bc -emit-llvm-uselists -disable-free -disable-llvm-verifier -discard-value-names -main-file-name main.cpp -mrelocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -v -resource-dir /home/user/opt/llvm/lib/clang/6.0.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward -internal-isystem /usr/local/include -internal-isystem /home/user/opt/llvm/lib/clang/6.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -internal-isystem /usr/local/include -internal-isystem /home/user/opt/llvm/lib/clang/6.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir /tmp -ferror-limit 19 -fmessage-length 190 -fopenmp -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o /tmp/main-be2d35.bc -x c++ main.cpp -fopenmp-targets=nvptx64-nvidia-cuda
clang -cc1 version 6.0.0 based upon LLVM 6.0.0svn default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/include"
ignoring nonexistent directory "/include"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward"
ignoring duplicate directory "/usr/local/include"
ignoring duplicate directory "/home/user/opt/llvm/lib/clang/6.0.0/include"
ignoring duplicate directory "/usr/include/x86_64-linux-gnu"
ignoring duplicate directory "/usr/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0
 /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0
 /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward
 /usr/local/include
 /home/user/opt/llvm/lib/clang/6.0.0/include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
 "/home/user/opt/llvm/bin/clang-6.0" -cc1 -triple nvptx64-nvidia-cuda -aux-triple x86_64-unknown-linux-gnu -S -disable-free -disable-llvm-verifier -discard-value-names -main-file-name main.cpp -mrelocation-model pic -pic-level 2 -mthread-model posix -mdisable-fp-elim -fmath-errno -no-integrated-as -fuse-init-array -mlink-cuda-bitcode /home/user/opt/pgi/linux86-64/2017/cuda/8.0/nvvm/libdevice/libdevice.compute_20.10.bc -target-feature +ptx42 -target-cpu sm_20 -dwarf-column-info -debugger-tuning=gdb -v -resource-dir /home/user/opt/llvm/lib/clang/6.0.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward -internal-isystem /usr/local/include -internal-isystem /home/user/opt/llvm/lib/clang/6.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -internal-isystem /usr/local/include -internal-isystem /home/user/opt/llvm/lib/clang/6.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fno-dwarf-directory-asm -fdebug-compilation-dir /tmp -ferror-limit 19 -fmessage-length 190 -fopenmp -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o /tmp/main-7ffbd7.s -x c++ main.cpp -fopenmp-is-device -fopenmp-host-ir-file-path /tmp/main-be2d35.bc
clang -cc1 version 6.0.0 based upon LLVM 6.0.0svn default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/include"
ignoring nonexistent directory "/include"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward"
ignoring duplicate directory "/usr/local/include"
ignoring duplicate directory "/home/user/opt/llvm/lib/clang/6.0.0/include"
ignoring duplicate directory "/usr/include/x86_64-linux-gnu"
ignoring duplicate directory "/usr/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0
 /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0
 /usr/lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward
 /usr/local/include
 /home/user/opt/llvm/lib/clang/6.0.0/include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
"/home/user/opt/pgi/linux86-64/2017/cuda/8.0/bin/ptxas" -m64 -O0 -v --gpu-name sm_20 --output-file /tmp/main-64fc86.cubin /tmp/main-ca9e59.s -c
ptxas info    : 1 bytes gmem, 8 bytes cmem[14]
ptxas info    : Compiling entry function '__omp_offloading_803_18004c0_main_l3' for 'sm_20'
ptxas info    : Function properties for __omp_offloading_803_18004c0_main_l3
0 bytes stack frame, 0 bytes spill stores, 0 bytes spill loads
ptxas info    : Used 5 registers, 32 bytes cmem[0]
ptxas info    : Function properties for __omp_offloading_803_18004c0_main_l3_worker
24 bytes stack frame, 8 bytes spill stores, 8 bytes spill loads
"/home/user/opt/pgi/linux86-64/2017/cuda/8.0/bin/nvlink" -o /tmp/main-f247e3.out -v -arch sm_20 -L/home/user/opt/llvm/lib -lomptarget-nvptx main-64fc86.cubin
nvlink error   : Undefined reference to '__kmpc_kernel_init' in 'main-64fc86.cubin'
nvlink error   : Undefined reference to '__kmpc_kernel_deinit' in 'main-64fc86.cubin'
nvlink error   : Undefined reference to '__kmpc_kernel_parallel' in 'main-64fc86.cubin'
nvlink error   : Undefined reference to '__kmpc_kernel_end_parallel' in 'main-64fc86.cubin'
nvlink info    : 1 bytes gmem, 8 bytes cmem[14]
nvlink info    : Function properties for '__omp_offloading_803_18004c0_main_l3':
nvlink info    : used 18 registers, 24 stack, 0 bytes smem, 32 bytes cmem[0], 0 bytes lmem
clang-6.0: error: fatbinary command failed with exit code 255 (use -v to see invocation)

Любая идея, какая библиотека должна иметь эти __kmpc* символы? Я пытался бежать:

nm libomptarget.so | grep __kmpc_kernel_parallel

а также

nm libomptarget.rtl.cuda.so | grep __kmpc_kernel_parallel,

но обе команды ничего не возвращают.

Наконец, если я удалю -fopenmp-targets=nvptx64-nvidia-cuda из моих флагов компиляции я не получаю ошибок компоновщика. Но, конечно, в этом случае код CUDA не генерируется.

Любые отзывы, которые могут помочь мне выяснить, что происходит, где эти символы должны находиться и почему их нет, приветствуются.

1

cuda openmp llvm-clang

Источник

user2301114 10 сен '17 в 20:10

1 ответ

Решение

Другие вопросы по тегам cuda openmp llvm-clang

user7979812 12 сен '17 в 00:53 2017-09-12 00:53 · Accepted Answer · 2017-09-12 00:53

К сожалению, поддержка разгрузки целевых объектов OMP для устройства nvptx еще не была расширена. Последняя ветка доступна на github с инструкциями по сборке на вики https://github.com/clang-ykt/clang/wiki

2

Источник

user7979812 12 сен '17 в 00:53