[flang] Changes to map variables in link clause of declare target

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -1120,7 +1120,21 @@ genTargetOp(Fortran::lower::AbstractConverter &converter,
         if (auto refType = baseOp.getType().dyn_cast<fir::ReferenceType>())
           eleType = refType.getElementType();
 
-        if (fir::isa_trivial(eleType) || fir::isa_char(eleType)) {
+        // If a variable is specified in declare target link and if device
+        // type is not specified as `nohost`, it needs to be mapped tofrom
+        mlir::ModuleOp mod = converter.getFirOpBuilder().getModule();
+        mlir::Operation *op = mod.lookupSymbol(converter.mangleName(sym));
+        auto declareTargetOp =
+            llvm::dyn_cast_if_present<mlir::omp::DeclareTargetInterface>(op);
+        if (declareTargetOp && declareTargetOp.isDeclareTarget()) {
+          if (declareTargetOp.getDeclareTargetCaptureClause() ==
+                  mlir::omp::DeclareTargetCaptureClause::link &&
+              declareTargetOp.getDeclareTargetDeviceType() !=
+                  mlir::omp::DeclareTargetDeviceType::nohost) {
+            mapFlag |= llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_TO;
+            mapFlag |= llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_FROM;
+          }
+        } else if (fir::isa_trivial(eleType) || fir::isa_char(eleType)) {
           captureKind = mlir::omp::VariableCaptureKind::ByCopy;
         } else if (!fir::isa_builtin_cptr_type(eleType)) {
           mapFlag |= llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_TO;

flang/test/Lower/OpenMP/declare-target-link-tarop-cap.f90

@@ -0,0 +1,55 @@
+!RUN: %flang_fc1 -emit-hlfir -fopenmp %s -o - | FileCheck %s
+!RUN: %flang_fc1 -emit-hlfir -fopenmp -fopenmp-is-device %s -o - | FileCheck %s
+!RUN: bbc -emit-hlfir -fopenmp %s -o - | FileCheck %s
+!RUN: bbc -emit-hlfir -fopenmp -fopenmp-is-target-device %s -o - | FileCheck %s
+
+program test_link
+
+  integer :: test_int = 1
+  !$omp declare target link(test_int)
+
+  integer :: test_array_1d(3) = (/1,2,3/)
+  !$omp declare target link(test_array_1d)
+
+  integer, pointer :: test_ptr1
+  !$omp declare target link(test_ptr1)
+
+  integer, target :: test_target = 1
+  !$omp declare target link(test_target)
+
+  integer, pointer :: test_ptr2
+  !$omp declare target link(test_ptr2)
+
+  !CHECK-DAG: {{%.*}} = omp.map_info var_ptr({{%.*}} : !fir.ref<i32>, i32) map_clauses(implicit, tofrom) capture(ByRef) -> !fir.ref<i32> {name = "test_int"}
+  !$omp target
+    test_int = test_int + 1
+  !$omp end target
+
+
+  !CHECK-DAG: {{%.*}} = omp.map_info var_ptr({{%.*}} : !fir.ref<!fir.array<3xi32>>, !fir.array<3xi32>) map_clauses(implicit, tofrom) capture(ByRef) bounds({{%.*}}) -> !fir.ref<!fir.array<3xi32>> {name = "test_array_1d"}
+  !$omp target
+    do i = 1,3
+      test_array_1d(i) = i * 2
+    end do
+  !$omp end target
+
+  allocate(test_ptr1)
+  test_ptr1 = 1
+  !CHECK-DAG: {{%.*}} = omp.map_info var_ptr({{%.*}} : !fir.ref<!fir.box<!fir.ptr<i32>>>, !fir.box<!fir.ptr<i32>>) map_clauses(implicit, tofrom) capture(ByRef) members({{%.*}} : !fir.llvm_ptr<!fir.ref<i32>>) -> !fir.ref<!fir.box<!fir.ptr<i32>>> {name = "test_ptr1"}
+  !$omp target
+    test_ptr1 = test_ptr1 + 1
+  !$omp end target
+
+  !CHECK-DAG: {{%.*}} = omp.map_info var_ptr({{%.*}} : !fir.ref<i32>, i32) map_clauses(implicit, tofrom) capture(ByRef) -> !fir.ref<i32> {name = "test_target"}
+  !$omp target
+    test_target = test_target + 1
+  !$omp end target
+
+
+  !CHECK-DAG: {{%.*}} = omp.map_info var_ptr({{%.*}} : !fir.ref<!fir.box<!fir.ptr<i32>>>, !fir.box<!fir.ptr<i32>>) map_clauses(implicit, tofrom) capture(ByRef) members({{%.*}} : !fir.llvm_ptr<!fir.ref<i32>>) -> !fir.ref<!fir.box<!fir.ptr<i32>>> {name = "test_ptr2"}
+  test_ptr2 => test_target
+  !$omp target
+    test_ptr2 = test_ptr2 + 1
+  !$omp end target
+
+end

openmp/libomptarget/test/offloading/fortran/declare-target-vars-in-target-region.f90

@@ -0,0 +1,81 @@
+! Offloading test with a target region mapping a declare target
+! Fortran array writing some values to it and checking the host
+! correctly receives the updates made on the device.
+! REQUIRES: flang
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+module test_0
+  implicit none
+  INTEGER :: arr1(10) = (/0,0,0,0,0,0,0,0,0,0/)
+  INTEGER :: arr2(10) = (/0,0,0,0,0,0,0,0,0,0/)
+  !$omp declare target link(arr1) enter(arr2)
+  INTEGER :: scalar = 1
+  !$omp declare target link(scalar)
+end module test_0
+
+subroutine test_with_array_link_and_tofrom()
+  use test_0
+  integer :: i = 1
+  integer :: j = 11
+  !$omp target map(tofrom:arr1, i, j)
+  do while (i <= j)
+      arr1(i) = i;
+      i = i + 1
+  end do
+  !$omp end target
+
+  ! CHECK: 1 2 3 4 5 6 7 8 9 10
+  PRINT *, arr1(:)
+end subroutine test_with_array_link_and_tofrom
+
+subroutine test_with_array_link_only()
+  use test_0
+  integer :: i = 1
+  integer :: j = 11
+  !$omp target map(i, j)
+      do while (i <= j)
+          arr1(i) = i + 1;
+          i = i + 1
+      end do
+  !$omp end target
+
+  ! CHECK: 2 3 4 5 6 7 8 9 10 11
+  PRINT *, arr1(:)
+end subroutine test_with_array_link_only
+
+subroutine test_with_array_enter_only()
+  use test_0
+  integer :: i = 1
+  integer :: j = 11
+  !$omp target map(i, j)
+      do while (i <= j)
+          arr2(i) = i + 1;
+          i = i + 1
+      end do
+  !$omp end target
+
+  ! CHECK: 0 0 0 0 0 0 0 0 0 0
+  PRINT *, arr2(:)
+end subroutine test_with_array_enter_only
+
+subroutine test_with_scalar_link_only()
+  use test_0
+  !$omp target
+      scalar = 10
+  !$omp end target
+
+  ! CHECK: 10
+  PRINT *, scalar
+end subroutine test_with_scalar_link_only
+
+program main
+  call test_with_array_link_and_tofrom()
+  call test_with_array_link_only()
+  call test_with_array_enter_only()
+  call test_with_scalar_link_only()
+end program