我想使用LLVM / Clang在我的Nvidia GPU上运行OpenMP4 +代码。我按照此处的说明从trunk下载并编译了llvm / clang / omp库：https://clang.llvm.org/get_started.html和此处：https://openmp.llvm.org/。我没有构建Compiler-RT和libcxx，但我认为这没有任何区别。
我的CMake命令是：architecture behavior of Counter is
signal q: std_logic_vector(7 downto 0);
begin
process(clock, choose)
begin
if clear = '1' then
q <= q - q;
else
if rising_edge(clock) then
-- when choose is '1', the process if for increment
if(choose = '1') then
case incodec is
when "001" => q <= q + 1;
when "011" => q <= q + 10;
when "111" => q <= q + 11;
when others => q <= q;
end case;
-- when choose is '0', the process if for decrement
elsif choose = '0' then
case incodec is
when "001" => q <= q - 1;
when "011" => q <= q - 10;
when "111" => q <= q - 11;
when others => q <= q;
end case;
end if;
end if;
end if;
case q(7 downto 4) is
-- 6543210
when "0000" => hex7 <= "1000000"; --0
when "0001" => hex7 <= "1111001"; --1
when "0010" => hex7 <= "0100100"; --2
when "0011" => hex7 <= "0110000"; --3
when "0100" => hex7 <= "0011001"; --4
when "0101" => hex7 <= "0010010"; --5
when "0110" => hex7 <= "0000010"; --6
when "0111" => hex7 <= "1111000"; --7
when "1000" => hex7 <= "0000000"; --8
when "1001" => hex7 <= "0010000"; --9
when "1010" => hex7 <= "0001000"; --10/A
when "1011" => hex7 <= "0000011"; --11/B/b
when "1100" => hex7 <= "1000110"; --12/C
when "1101" => hex7 <= "0100001"; --13/D/d
when "1110" => hex7 <= "0000110"; --14/E
when "1111" => hex7 <= "0001110"; --15/F
when others => hex7 <= "0111111"; -- -
end case;
case q(3 downto 0) is
-- 6543210
when "0000" => hex6 <= "1000000"; --0
when "0001" => hex6 <= "1111001"; --1
when "0010" => hex6 <= "0100100"; --2
when "0011" => hex6 <= "0110000"; --3
when "0100" => hex6 <= "0011001"; --4
when "0101" => hex6 <= "0010010"; --5
when "0110" => hex6 <= "0000010"; --6
when "0111" => hex6 <= "1111000"; --7
when "1000" => hex6 <= "0000000"; --8
when "1001" => hex6 <= "0010000"; --9
when "1010" => hex6 <= "0001000"; --10/A
when "1011" => hex6 <= "0000011"; --11/B/b
when "1100" => hex6 <= "1000110"; --12/C
when "1101" => hex6 <= "0100001"; --13/D/d
when "1110" => hex6 <= "0000110"; --14/E
when "1111" => hex6 <= "0001110"; --15/F
when others => hex6 <= "0111111"; -- -
end case;
end behavior
我用一个OpenMP cmake -G "Unix Makefiles" ../llvm -DCMAKE_BUILD_TYPE=Release -DOPENMP_ENABLE_LIBOMPTARGET=ON指令编写了一个非常基本的程序：
target我用这个编译它：
int main(void)
{
#pragma omp target
{
}
return 0;
}
如果你问：是的，我还没有为编译器设置路径，但我确保/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指向LD_LIBRARY_PATH所在的位置。
这是执行上述命令后得到的输出/错误（最后~10行显示错误）：
libomptarget知道哪个库应该包含这些<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)
符号？
我试着跑：
__kmpc*
和
nm libomptarget.so | grep __kmpc_kernel_parallel，
但两个命令都没有返回任何内容。
最后，如果我从编译标志中删除nm libomptarget.rtl.cuda.so | grep __kmpc_kernel_parallel，我就不会收到链接器错误。但当然在这种情况下不会生成CUDA代码。
任何可以帮助我弄清楚发生了什么的反馈，应该找到这些符号的位置，以及它们不存在的原因，都非常受欢迎。
答案 0 :(得分：2)
不幸的是，针对nvptx设备的OMP目标卸载支持还没有被上流。 github上有一个最近的分支，在wiki上有构建说明 https://github.com/clang-ykt/clang/wiki