In 'libgomp/target.c:gomp_unmap_vars_internal', defer 'gomp_remove_var'

An upcoming change requires that 'gomp_remove_var' be deferred until after all
'gomp_copy_dev2host' calls have been handled.

Do this likewise to how commit 275c736e732d29934e4d22e8f030d5aae8c12a52
"libgomp: Structure element mapping for OpenMP 5.0" changed 'gomp_exit_data'.

	libgomp/
	* target.c (gomp_unmap_vars_internal): Queue splay-tree keys for
	removal after main loop.

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 85ebab14ba84ff9c9912bb664f869761af5cd8cc..9360db66b03e238d13fb90cc80b77d2fc91a06fd 100644 (file)
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,5 +1,8 @@
 2023-03-24  Thomas Schwinge  <thomas@codesourcery.com>
 
+       * target.c (gomp_unmap_vars_internal): Queue splay-tree keys for
+       removal after main loop.
+
        PR other/76739
        * oacc-parallel.c (GOACC_parallel_keyed): Given OpenACC 'async',
        defer 'free' of non-contiguous array support data structures.

diff --git a/libgomp/target.c b/libgomp/target.c
index aaa597f66101aa8988bc9054bb5a040d7ec754a4..107c3567a3023e77b04ef74efdb292becbfea651 100644 (file)
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -2180,6 +2180,9 @@ gomp_unmap_vars_internal (struct target_mem_desc *tgt, bool do_copyfrom,
                             false, NULL);
     }
 
+  size_t nrmvars = 0;
+  splay_tree_key remove_vars[tgt->list_count];
+
   for (i = 0; i < tgt->list_count; i++)
     {
       splay_tree_key k = tgt->list[i].key;
@@ -2201,16 +2204,21 @@ gomp_unmap_vars_internal (struct target_mem_desc *tgt, bool do_copyfrom,
                            (void *) (k->tgt->tgt_start + k->tgt_offset
                                      + tgt->list[i].offset),
                            tgt->list[i].length);
+      /* Queue all removals together for processing below.
+        See also 'gomp_exit_data'.  */
       if (do_remove)
-       {
-         struct target_mem_desc *k_tgt = k->tgt;
-         bool is_tgt_unmapped = gomp_remove_var (devicep, k);
-         /* It would be bad if TGT got unmapped while we're still iterating
-            over its LIST_COUNT, and also expect to use it in the following
-            code.  */
-         assert (!is_tgt_unmapped
-                 || k_tgt != tgt);
-       }
+       remove_vars[nrmvars++] = k;
+    }
+
+  for (i = 0; i < nrmvars; i++)
+    {
+      splay_tree_key k = remove_vars[i];
+      struct target_mem_desc *k_tgt = k->tgt;
+      bool is_tgt_unmapped = gomp_remove_var (devicep, k);
+      /* It would be bad if TGT got unmapped while we're still iterating over
+        its LIST_COUNT, and also expect to use it in the following code.  */
+      assert (!is_tgt_unmapped
+             || k_tgt != tgt);
     }
 
   if (aq)
@@ -4157,7 +4165,7 @@ gomp_exit_data (struct gomp_device_descr *devicep, size_t mapnum,
                               false, NULL);
       }
 
-  int nrmvars = 0;
+  size_t nrmvars = 0;
   splay_tree_key remove_vars[mapnum];
 
   for (i = 0; i < mapnum; i++)
@@ -4220,10 +4228,6 @@ gomp_exit_data (struct gomp_device_descr *devicep, size_t mapnum,
             errors if we still have following element siblings to copy back.
             While we're at it, it also seems more disciplined to simply
             queue all removals together for processing below.
-
-            Structured block unmapping (i.e. gomp_unmap_vars_internal) should
-            not have this problem, since they maintain an additional
-            tgt->refcount = 1 reference to the target_mem_desc to start with.
          */
          if (do_remove)
            remove_vars[nrmvars++] = k;
@@ -4238,7 +4242,7 @@ gomp_exit_data (struct gomp_device_descr *devicep, size_t mapnum,
        }
     }
 
-  for (int i = 0; i < nrmvars; i++)
+  for (i = 0; i < nrmvars; i++)
     gomp_remove_var (devicep, remove_vars[i]);
 
   gomp_mutex_unlock (&devicep->lock);