[OpenMP 5.0] Deprecate nest-var and associated features

Nest-var, OMP_NESTED, omp_set_nested()., and omp_get_nested() have been
deprecated in the 5.0 spec. Initial nesting info is now derived from
OMP_MAX_ACTIVE_LEVELS, OMP_NUM_THREADS, and OMP_PROC_BIND.

This patch deprecates the internal ICV that corresponds to nest-var, and
replaces it with the max-active-levels-var ICV to determine nesting. The
change still allows for use of OMP_NESTED (according to 5.0 changes),
omp_get_nested, and omp_set_nested, which have had deprecation messages
added to them. The change allows certain settings of OMP_NUM_THREADS,
OMP_PROC_BIND, and OMP_MAX_ACTIVE_LEVELS to turn on nesting, but
OMP_NESTED=0 will still force nesting to be off.

The runtime now prints informative messages about deprecation of
OMP_NESTED, omp_set_nested(), and omp_get_nested(), when those
environment variables or routines are used. It also prints deprecated
message in output for KMP_SETTINGS and OMP_DISPLAY_ENV for OMP_NESTED.
This patch also fixes OMP_DISPLAY_ENV output for OMP_TARGET_OFFLOAD.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D58408

llvm-svn: 355138

1 files changed, 3 insertions, 7 deletions

diff --git a/openmp/runtime/src/kmp_runtime.cpp b/openmp/runtime/src/kmp_runtime.cpp
index 2a9e31d37c5..e6b673b425d 100644
--- a/openmp/runtime/src/kmp_runtime.cpp
+++ b/openmp/runtime/src/kmp_runtime.cpp
@@ -1719,11 +1719,11 @@ int __kmp_fork_call(ident_t *loc, int gtid,
       // parallel out of teams construct). This code moved here from
       // __kmp_reserve_threads() to speedup nested serialized parallels.
       if (nthreads > 1) {
-        if ((!get__nested(master_th) && (root->r.r_in_parallel
+        if ((get__max_active_levels(master_th) == 1 && (root->r.r_in_parallel
 #if OMP_40_ENABLED
-                                         && !enter_teams
+                                                        && !enter_teams
 #endif /* OMP_40_ENABLED */
-                                         )) ||
+                                                        )) ||
             (__kmp_library == library_serial)) {
           KC_TRACE(10, ("__kmp_fork_call: T#%d serializing team; requested %d"
                         " threads\n",
@@ -3150,8 +3150,6 @@ static kmp_internal_control_t __kmp_get_global_icvs(void) {
 
   kmp_internal_control_t g_icvs = {
     0, // int serial_nesting_level; //corresponds to value of th_team_serialized
-    (kmp_int8)__kmp_dflt_nested, // int nested; //internal control
-    // for nested parallelism (per thread)
     (kmp_int8)__kmp_global.g.g_dynamic, // internal control for dynamic
     // adjustment of threads (per thread)
     (kmp_int8)__kmp_env_blocktime, // int bt_set; //internal control for
@@ -3207,7 +3205,6 @@ static void __kmp_initialize_root(kmp_root_t *root) {
   root->r.r_active = FALSE;
   root->r.r_in_parallel = 0;
   root->r.r_blocktime = __kmp_dflt_blocktime;
-  root->r.r_nested = __kmp_dflt_nested;
 
   /* setup the root team for this task */
   /* allocate the root team structure */
@@ -3432,7 +3429,6 @@ void __kmp_print_structure(void) {
         __kmp_print_structure_thread("    Uber Thread:  ",
                                      root->r.r_uber_thread);
         __kmp_printf("    Active?:      %2d\n", root->r.r_active);
-        __kmp_printf("    Nested?:      %2d\n", root->r.r_nested);
         __kmp_printf("    In Parallel:  %2d\n",
                      KMP_ATOMIC_LD_RLX(&root->r.r_in_parallel));
         __kmp_printf("\n");