diff mbox series

libgomp: Fix reverse offload issues

Message ID 4c058f14-c719-b66a-f556-9bda3a4c4556@codesourcery.com
State New
Headers
Series libgomp: Fix reverse offload issues |

Commit Message

Tobias Burnus Feb. 2, 2023, 2:13 p.m. UTC 
  Found when testing AMD GCN offloading, the second issue came up with
libgomp.fortran/reverse-offload-5.f90. (But oddly not with nvptx.)

While the first one (new test: libgomp.fortran/reverse-offload-6.f90)
came up when debugging the issue.

Tobias
-----------------
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Comments

Tobias Burnus Feb. 3, 2023, 10:38 a.m. UTC | #1 
Now committed as obvious as
r13-5680-g0b1ce70a813b98ef2893779d14ad6c90c5d06a71.

I improved the wording in the commit comment a bit, compared to previous
attachment and I have verified that those features work with AMDGCN* and
without offloading.

Tobias

(* it seems as if there is still another issue with mapping, this time
for array-descriptor variables that do not exist on the host, i.e. that
have to be fully mapped to the host. I will look into this today or Monday.)

On 02.02.23 15:13, Tobias Burnus wrote:
> Found when testing AMD GCN offloading, the second issue came up with
> libgomp.fortran/reverse-offload-5.f90. (But oddly not with nvptx.)
>
> While the first one (new test: libgomp.fortran/reverse-offload-6.f90)
> came up when debugging the issue.
>
> Tobias
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße
> 201, 80634 München; Gesellschaft mit beschränkter Haftung;
> Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft:
> München; Registergericht München, HRB 106955
-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
diff mbox series

Patch

libgomp: Fix reverse offload issues

If there is nothing to map, skip the mapping and attempting to copy
addrs, sizes and kinds which may have issues for size = 0.

Additionally, it could happen that a non-allocated address was deallocated,
e.g. a pointer set - such that there was a double free for the actual data
or in multiple other ways.

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

 libgomp/target.c                                   |  8 +++---
 .../libgomp.fortran/reverse-offload-6.f90          | 32 ++++++++++++++++++++++
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/libgomp/target.c b/libgomp/target.c
index b16ee761a95..c1682caea13 100644
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -3324,7 +3324,7 @@  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;
@@ -3402,7 +3402,7 @@  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;
@@ -3638,7 +3638,7 @@  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;
@@ -3680,7 +3680,7 @@  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
index 00000000000..04866edbba7
--- /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