libgomp: Add omp_in_explicit_task support

This is pretty straightforward, if gomp_thread ()->task is NULL,
it can't be explicit task, otherwise if
gomp_thread ()->task->kind == GOMP_TASK_IMPLICIT, it is an implicit
task, otherwise explicit task.

2022-10-12  Jakub Jelinek  <jakub@redhat.com>

	* omp.h.in (omp_in_explicit_task): Declare.
	* omp_lib.h.in (omp_in_explicit_task): Likewise.
	* omp_lib.f90.in (omp_in_explicit_task): New interface.
	* libgomp.map (OMP_5.2): New symbol version, export
	omp_in_explicit_task and omp_in_explicit_task_.
	* task.c (omp_in_explicit_task): New function.
	* fortran.c (omp_in_explicit_task): Add ialias_redirect.
	(omp_in_explicit_task_): New function.
	* libgomp.texi (OpenMP 5.2): Mark omp_in_explicit_task as implemented.
	* testsuite/libgomp.c-c++-common/task-in-explicit-1.c: New test.
	* testsuite/libgomp.c-c++-common/task-in-explicit-2.c: New test.
	* testsuite/libgomp.c-c++-common/task-in-explicit-3.c: New test.

10 files changed, 202 insertions, 2 deletions

diff --git a/libgomp/fortran.c b/libgomp/fortran.c
index d984ce5..72784ec 100644
--- a/libgomp/fortran.c
+++ b/libgomp/fortran.c
@@ -76,6 +76,7 @@ ialias_redirect (omp_get_ancestor_thread_num)
 ialias_redirect (omp_get_team_size)
 ialias_redirect (omp_get_active_level)
 ialias_redirect (omp_in_final)
+ialias_redirect (omp_in_explicit_task)
 ialias_redirect (omp_get_cancellation)
 ialias_redirect (omp_get_proc_bind)
 ialias_redirect (omp_get_num_places)
@@ -482,6 +483,12 @@ omp_in_final_ (void)
   return omp_in_final ();
 }
 
+int32_t
+omp_in_explicit_task_ (void)
+{
+  return omp_in_explicit_task ();
+}
+
 void
 omp_set_num_teams_ (const int32_t *num_teams)
 {
diff --git a/libgomp/libgomp.map b/libgomp/libgomp.map
index 46d5f10..e76c126 100644
--- a/libgomp/libgomp.map
+++ b/libgomp/libgomp.map
@@ -234,6 +234,12 @@ OMP_5.1.1 {
 	omp_target_memcpy_rect_async;
 } OMP_5.1;
 
+OMP_5.2 {
+  global:
+	omp_in_explicit_task;
+	omp_in_explicit_task_;
+} OMP_5.1.1;
+
 GOMP_1.0 {
   global:
 	GOMP_atomic_end;
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index d8c798c..148728e 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -360,8 +360,8 @@ to address of matching mapped list item per 5.1, Sect. 2.21.7.2 @tab N @tab
 
 @multitable @columnfractions .60 .10 .25
 @headitem Description @tab Status @tab Comments
-@item @code{omp_in_explicit_task} routine and @emph{implicit-task-var} ICV
-      @tab N @tab
+@item @code{omp_in_explicit_task} routine and @emph{explicit-task-var} ICV
+      @tab Y @tab
 @item @code{omp}/@code{ompx}/@code{omx} sentinels and @code{omp_}/@code{ompx_}
       namespaces @tab N/A
       @tab warning for @code{ompx/omx} sentinels@footnote{The @code{ompx}
diff --git a/libgomp/omp.h.in b/libgomp/omp.h.in
index 925a650..bfa4e6a 100644
--- a/libgomp/omp.h.in
+++ b/libgomp/omp.h.in
@@ -244,6 +244,7 @@ extern int omp_get_team_size (int) __GOMP_NOTHROW;
 extern int omp_get_active_level (void) __GOMP_NOTHROW;
 
 extern int omp_in_final (void) __GOMP_NOTHROW;
+extern int omp_in_explicit_task (void) __GOMP_NOTHROW;
 
 extern int omp_get_cancellation (void) __GOMP_NOTHROW;
 extern omp_proc_bind_t omp_get_proc_bind (void) __GOMP_NOTHROW;
diff --git a/libgomp/omp_lib.f90.in b/libgomp/omp_lib.f90.in
index 7ba115f..04f32db 100644
--- a/libgomp/omp_lib.f90.in
+++ b/libgomp/omp_lib.f90.in
@@ -445,6 +445,12 @@
         end interface
 
         interface
+          function omp_in_explicit_task ()
+            logical (4) :: omp_in_explicit_task
+          end function omp_in_explicit_task
+        end interface
+
+        interface
           function omp_get_cancellation ()
             logical (4) :: omp_get_cancellation
           end function omp_get_cancellation
diff --git a/libgomp/omp_lib.h.in b/libgomp/omp_lib.h.in
index 3626836..ecfb934 100644
--- a/libgomp/omp_lib.h.in
+++ b/libgomp/omp_lib.h.in
@@ -220,6 +220,8 @@
 
       external omp_in_final
       logical(4) omp_in_final
+      external omp_in_explicit_task
+      logical(4) omp_in_explicit_task
 
       external omp_get_cancellation
       logical(4) omp_get_cancellation
diff --git a/libgomp/task.c b/libgomp/task.c
index 7766535..a7e67e8 100644
--- a/libgomp/task.c
+++ b/libgomp/task.c
@@ -2687,6 +2687,16 @@ omp_in_final (void)
 
 ialias (omp_in_final)
 
+int
+omp_in_explicit_task (void)
+{
+  struct gomp_thread *thr = gomp_thread ();
+  struct gomp_task *task = thr->task;
+  return task && task->kind != GOMP_TASK_IMPLICIT;
+}
+
+ialias (omp_in_explicit_task)
+
 void
 omp_fulfill_event (omp_event_handle_t event)
 {
diff --git a/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-1.c b/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-1.c
new file mode 100644
index 0000000..a228d93
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-1.c
@@ -0,0 +1,106 @@
+/* { dg-do run } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+int
+main ()
+{
+  if (omp_in_explicit_task ())
+    abort ();
+  #pragma omp task
+  if (!omp_in_explicit_task ())
+    abort ();
+  #pragma omp task final (1)
+  {
+    if (!omp_in_explicit_task ())
+      abort ();
+    #pragma omp task 
+    if (!omp_in_explicit_task ())
+      abort ();
+  }
+  #pragma omp parallel
+  {
+    if (omp_in_explicit_task ())
+      abort ();
+    #pragma omp task if (0)
+      {
+	if (!omp_in_explicit_task ())
+	  abort ();
+	#pragma omp task if (0)
+	  if (!omp_in_explicit_task ())
+	    abort ();
+      }
+    #pragma omp task final (1)
+      if (!omp_in_explicit_task ())
+	abort ();
+    #pragma omp barrier
+    if (omp_in_explicit_task ())
+      abort ();
+    #pragma omp taskloop num_tasks (24)
+    for (int i = 0; i < 32; ++i)
+      if (!omp_in_explicit_task ())
+	abort ();
+    #pragma omp masked
+    #pragma omp task
+    if (!omp_in_explicit_task ())
+      abort ();
+    #pragma omp barrier
+    if (omp_in_explicit_task ())
+      abort ();
+  }
+  #pragma omp target
+  {
+    if (omp_in_explicit_task ())
+      abort ();
+    #pragma omp task if (0)
+    if (!omp_in_explicit_task ())
+      abort ();
+    #pragma omp task
+    if (!omp_in_explicit_task ())
+      abort ();
+  }
+  #pragma omp target teams
+  {
+    #pragma omp distribute
+    for (int i = 0; i < 4; ++i)
+      if (omp_in_explicit_task ())
+	abort ();
+      else
+	{
+	  #pragma omp parallel
+	  {
+	    if (omp_in_explicit_task ())
+	      abort ();
+	    #pragma omp task
+	    if (!omp_in_explicit_task ())
+	      abort ();
+	    #pragma omp barrier
+	    if (omp_in_explicit_task ())
+	      abort ();
+	  }
+	}
+  }
+  #pragma omp teams
+  {
+    #pragma omp distribute
+    for (int i = 0; i < 4; ++i)
+      if (omp_in_explicit_task ())
+	abort ();
+      else
+	{
+	  #pragma omp parallel
+	  {
+	    if (omp_in_explicit_task ())
+	      abort ();
+	    #pragma omp task
+	    if (!omp_in_explicit_task ())
+	      abort ();
+	    #pragma omp barrier
+	    if (omp_in_explicit_task ())
+	      abort ();
+	  }
+	}
+  }
+  return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-2.c b/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-2.c
new file mode 100644
index 0000000..44df596
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-2.c
@@ -0,0 +1,26 @@
+/* { dg-do run } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+int
+main ()
+{
+  #pragma omp task
+  {
+    if (!omp_in_explicit_task ())
+      abort ();
+    #pragma omp task
+    {
+      if (!omp_in_explicit_task ())
+	abort ();
+      #pragma omp target nowait
+      if (omp_in_explicit_task ())
+	abort ();
+      if (!omp_in_explicit_task ())
+	abort ();
+      #pragma omp taskwait
+    }
+  }
+  return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-3.c b/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-3.c
new file mode 100644
index 0000000..40eb94d
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/task-in-explicit-3.c
@@ -0,0 +1,36 @@
+/* { dg-do run } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+int a;
+
+int
+main ()
+{
+  #pragma omp task
+  {
+    if (!omp_in_explicit_task ())
+      abort ();
+    #pragma omp task
+    {
+      if (!omp_in_explicit_task ())
+	abort ();
+      #pragma omp taskgroup task_reduction (+: a)
+      {
+	if (!omp_in_explicit_task ())
+	  abort ();
+	#pragma omp task in_reduction (+: a)
+	{
+	  ++a;
+	  if (!omp_in_explicit_task ())
+	    abort ();
+	}
+      }
+      if (!omp_in_explicit_task ())
+	abort ();
+      #pragma omp taskwait
+    }
+  }
+  return 0;
+}