libgomp: Fix reverse offload issues

If there is nothing to map, skip the mapping and avoid attempting to
copy 0 bytes from addrs, sizes and kinds.

Additionally, it could happen that a non-allocated address was deallocated,
such as a pointer set, leading to a free for the actual data.

libgomp/
	* target.c (gomp_target_rev): Handle mapnum == 0 and avoid
	freeing not allocated memory.
	* testsuite/libgomp.fortran/reverse-offload-6.f90: New test.

(cherry picked from commit 0b1ce70a813b98ef2893779d14ad6c90c5d06a71)

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 75a47a77ed7afaa8d58c4d69306c2b8a2445c1c8..2b716f67501e24a89cab5ab9142b0a1f4120ef81 100644 (file)
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,12 @@
+2023-02-03  Tobias Burnus  <tobias@codesourcery.com>
+
+       Backported from master:
+       2023-02-03  Tobias Burnus  <tobias@codesourcery.com>
+
+       * target.c (gomp_target_rev): Handle mapnum == 0 and avoid
+       freeing not allocated memory.
+       * testsuite/libgomp.fortran/reverse-offload-6.f90: New test.
+
 2023-02-01  Tobias Burnus  <tobias@codesourcery.com>
 
        Backported from master:

diff --git a/libgomp/target.c b/libgomp/target.c
index cda53d636d158ee5447e9731a887208557d1f56e..1272e8347c802657e7321a735129fbcd1f2a024f 100644 (file)
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -3521,7 +3521,7 @@ gomp_target_rev (uint64_t fn_ptr, uint64_t mapnum, uint64_t devaddrs_ptr,
     gomp_fatal ("Cannot find reverse-offload function");
   void (*host_fn)() = (void (*)()) n->k->host_start;
 
-  if (devicep->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
+  if ((devicep->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM) || mapnum == 0)
     {
       devaddrs = (uint64_t *) (uintptr_t) devaddrs_ptr;
       sizes = (uint64_t *) (uintptr_t) sizes_ptr;
@@ -3599,7 +3599,7 @@ gomp_target_rev (uint64_t fn_ptr, uint64_t mapnum, uint64_t devaddrs_ptr,
          }
     }
 
-  if (!(devicep->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM))
+  if (!(devicep->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM) && mapnum > 0)
     {
       size_t j, struct_cpy = 0;
       splay_tree_key n2;
@@ -3835,7 +3835,7 @@ gomp_target_rev (uint64_t fn_ptr, uint64_t mapnum, uint64_t devaddrs_ptr,
 
   host_fn (devaddrs);
 
-  if (!(devicep->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM))
+  if (!(devicep->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM) && mapnum > 0)
     {
       uint64_t struct_cpy = 0;
       bool clean_struct = false;
@@ -3877,7 +3877,7 @@ gomp_target_rev (uint64_t fn_ptr, uint64_t mapnum, uint64_t devaddrs_ptr,
              clean_struct = true;
              struct_cpy = sizes[i];
            }
-         else if (cdata[i].aligned)
+         else if (!cdata[i].present && cdata[i].aligned)
            gomp_aligned_free ((void *) (uintptr_t) devaddrs[i]);
          else if (!cdata[i].present)
            free ((void *) (uintptr_t) devaddrs[i]);

diff --git a/libgomp/testsuite/libgomp.fortran/reverse-offload-6.f90 b/libgomp/testsuite/libgomp.fortran/reverse-offload-6.f90
new file mode 100644 (file)
index 0000000..04866ed
--- /dev/null
+++ b/libgomp/testsuite/libgomp.fortran/reverse-offload-6.f90
@@ -0,0 +1,32 @@
+!
+! Ensure that a mapping with no argument works
+!
+
+module m
+  implicit none (type, external)
+  integer :: x = 32
+  integer :: dev_num2 = -1
+contains
+subroutine  foo()
+  use omp_lib, only: omp_get_device_num
+  x = x + 10
+  dev_num2 = omp_get_device_num()
+end
+end module m
+
+use m
+use omp_lib
+!$omp requires reverse_offload
+implicit none (type, external)
+integer :: dev_num = -1
+!$omp target map(from:dev_num)
+  dev_num = omp_get_device_num()
+  ! This calls GOMP_target_ext with number of maps = 0
+  !$omp target device(ancestor:1)
+    call foo
+  !$omp end target
+!$omp end target
+
+if (omp_get_num_devices() > 0 .and.  dev_num2 == dev_num) stop 1
+if (x /= 42) stop 2
+end