openacc: Fix standalone attach for Fortran assumed-shape array pointers

This patch makes it so that an "attach" operation for a Fortran pointer
with an array descriptor copies that array descriptor to the target,
and similarly that detach operations release the array descriptor.

2020-07-16  Julian Brown  <julian@codesourcery.com>
	    Thomas Schwinge  <thomas@codesourcery.com>

gcc/fortran/
	* trans-openmp.c (gfc_trans_omp_clauses): Rework OpenACC
	attach/detach handling for arrays with descriptors.

gcc/testsuite/
	* gfortran.dg/goacc/attach-descriptor.f90: New test.

libgomp/
	* testsuite/libgomp.oacc-fortran/attach-descriptor-1.f90: New test.
	* testsuite/libgomp.oacc-fortran/attach-descriptor-2.f90: New test.

Co-Authored-By: Thomas Schwinge <thomas@codesourcery.com>

2 files changed, 71 insertions, 0 deletions

diff --git a/libgomp/testsuite/libgomp.oacc-fortran/attach-descriptor-1.f90 b/libgomp/testsuite/libgomp.oacc-fortran/attach-descriptor-1.f90
new file mode 100644
index 0000000..5d79cbc
--- /dev/null
+++ b/libgomp/testsuite/libgomp.oacc-fortran/attach-descriptor-1.f90
@@ -0,0 +1,53 @@
+! { dg-do run }
+
+program att
+  use openacc
+  implicit none
+  type t
+    integer :: arr1(10)
+    integer, allocatable :: arr2(:)
+  end type t
+  integer :: i
+  type(t) :: myvar
+  integer, target :: tarr(10)
+  integer, pointer :: myptr(:)
+
+  allocate(myvar%arr2(10))
+
+  do i=1,10
+    myvar%arr1(i) = 0
+    myvar%arr2(i) = 0
+    tarr(i) = 0
+  end do
+
+  call acc_copyin(myvar)
+  call acc_copyin(myvar%arr2)
+  call acc_copyin(tarr)
+
+  myptr => tarr
+
+  !$acc enter data attach(myvar%arr2, myptr)
+
+  ! FIXME: This warning is emitted on the wrong line number.
+  ! { dg-warning "using vector_length \\(32\\), ignoring 1" "" { target openacc_nvidia_accel_selected } 38 }
+  !$acc serial present(myvar%arr2)
+  do i=1,10
+    myvar%arr1(i) = i
+    myvar%arr2(i) = i
+  end do
+  myptr(3) = 99
+  !$acc end serial
+
+  !$acc exit data detach(myvar%arr2, myptr)
+
+  call acc_copyout(myvar%arr2)
+  call acc_copyout(myvar)
+  call acc_copyout(tarr)
+
+  do i=1,10
+    if (myvar%arr1(i) .ne. i) stop 1
+    if (myvar%arr2(i) .ne. i) stop 2
+  end do
+  if (tarr(3) .ne. 99) stop 3
+
+end program att
diff --git a/libgomp/testsuite/libgomp.oacc-fortran/attach-descriptor-2.f90 b/libgomp/testsuite/libgomp.oacc-fortran/attach-descriptor-2.f90
new file mode 100644
index 0000000..58ef44e
--- /dev/null
+++ b/libgomp/testsuite/libgomp.oacc-fortran/attach-descriptor-2.f90
@@ -0,0 +1,18 @@
+! { dg-do run }
+
+program main
+  use openacc
+  implicit none
+  ! TODO Per PR96080, data types chosen so that we can create a
+  ! "pointer object 'data_p'" on the device.
+  integer, dimension(:), target :: data(1)
+  integer, dimension(:), pointer :: data_p
+
+  !TODO Per PR96080, not using OpenACC/Fortran runtime library routines.
+
+  !$acc enter data create(data)
+  data_p => data
+  !$acc enter data copyin(data_p)
+
+  !$acc enter data attach(data_p)
+end program main