[Numpy-discussion] Problem with compiling openacc with f2py

[Vikram Singh]

Ok, I got it to compile using

f2py -c -m --f90flags='-fopenmp -fopenacc -foffload=nvptx-none -foffload=-O3
-O3 -fPIC' hello hello.f90 -L/usr/local/cuda/lib64 -lcublas -lcudart
-lgomp

But now I get the import error,
/home/Experiments/fortran_python/hello.cpython-35m-x86_64-linux-gnu.so:
undefined symbol: __offload_func_table

Seems to me I have to link another library. But where is __offload_func_table

On Thu, Oct 27, 2016 at 1:30 PM, Vikram Singh <vikramsingh001 at gmail.com> wrote:
> I am a newbie to f2py so I have been creating simple test cases.
> Eventually I want to be able to use openacc subroutine from python. So
> here's the test case
>
>     module test
>
>      use iso_c_binding, only: sp => C_FLOAT, dp => C_DOUBLE, i8 => C_INT
>      use omp_lib
>      use openacc
>
>      implicit none
>
>      contains
>
>        subroutine add_acc (a, b, n, c)
>           integer(kind=i8), intent(in)  :: n
>           real(kind=dp), intent(in)  :: a(n)
>           real(kind=dp), intent(in)  :: b(n)
>           real(kind=dp), intent(out) :: c(n)
>
>           integer(kind=i8)  :: i
>
>           !$acc kernels
>           do i = 1, n
>               c(i) = a(i) + b(i)
>           end do
>           !$acc end kernels
>
>       end subroutine add_acc
>
>       subroutine add_omp (a, b, n, c)
>           integer(kind=i8), intent(in)  :: n
>           real(kind=dp), intent(in)  :: a(n)
>           real(kind=dp), intent(in)  :: b(n)
>           real(kind=dp), intent(out) :: c(n)
>
>           integer(kind=i8)  :: i, j
>
>           !$omp parallel do
>           do i = 1, n
>               c(i) = a(i) + b(i)
>           end do
>           !$omp end parallel do
>
>       end subroutine add_omp
>
>       subroutine nt (c)
>           integer(kind=i8), intent(out) :: c
>
>           c = omp_get_max_threads()
>
>       end subroutine nt
>
>       subroutine mult (a, b, c)
>           real(kind=dp), intent(in)  :: a
>           real(kind=dp), intent(in)  :: b
>           real(kind=dp), intent(out) :: c
>
>           c = a * b
>
>       end subroutine mult
>
>     end module test
>
> I compile using
>
> f2py -c -m --f90flags='-fopenacc -foffload=nvptx-none -foffload=-O3
> -O3 -fPIC' hello hello.f90 -L/usr/local/cuda/lib64 -lcublas -lcudart
> -lgomp
>
> Now, until I add the acc directives everything works fine. But as soon
> as I add the acc directives I get this error.
>
> gfortran:f90: /tmp/tmpld6ssow3/src.linux-x86_64-3.5/hello-f2pywrappers2.f90
> /home//Experiments/Nvidia/OpenACC/OLCFHack15/gcc6/install/bin/gfortran
> -Wall -g -Wall -g -shared
> /tmp/tmpld6ssow3/tmp/tmpld6ssow3/src.linux-x86_64-3.5/hellomodule.o
> /tmp/tmpld6ssow3/tmp/tmpld6ssow3/src.linux-x86_64-3.5/fortranobject.o
> /tmp/tmpld6ssow3/hello.o
> /tmp/tmpld6ssow3/tmp/tmpld6ssow3/src.linux-x86_64-3.5/hello-f2pywrappers2.o
> -L/usr/local/cuda/lib64 -L/home//usr/local/miniconda/lib -lcublas
> -lcudart -lgomp -lpython3.5m -lgfortran -o
> ./hello.cpython-35m-x86_64-linux-gnu.so
> /usr/bin/ld: /tmp/cc2yQ89d.target.o: relocation R_X86_64_32 against
> `.rodata' can not be used when making a shared object; recompile with
> -fPIC
> /tmp/cc2yQ89d.target.o: error adding symbols: Bad value
> collect2: error: ld returned 1 exit status
> /usr/bin/ld: /tmp/cc2yQ89d.target.o: relocation R_X86_64_32 against
> `.rodata' can not be used when making a shared object; recompile with
> -fPIC
> /tmp/cc2yQ89d.target.o: error adding symbols: Bad value
> collect2: error: ld returned 1 exit status
> error: Command "/home//Experiments/Nvidia/OpenACC/OLCFHack15/gcc6/install/bin/gfortran
> -Wall -g -Wall -g -shared
> /tmp/tmpld6ssow3/tmp/tmpld6ssow3/src.linux-x86_64-3.5/hellomodule.o
> /tmp/tmpld6ssow3/tmp/tmpld6ssow3/src.linux-x86_64-3.5/fortranobject.o
> /tmp/tmpld6ssow3/hello.o
> /tmp/tmpld6ssow3/tmp/tmpld6ssow3/src.linux-x86_64-3.5/hello-f2pywrappers2.o
> -L/usr/local/cuda/lib64 -L/home//usr/local/miniconda/lib -lcublas
> -lcudart -lgomp -lpython3.5m -lgfortran -o
> ./hello.cpython-35m-x86_64-linux-gnu.so" failed with exit status 1
>
> I don't get why just putting acc directives should create errors, when
> omp does not.
>
> Vikram