openmp: Implement omp_get_device_num routine

This patch implements the omp_get_device_num library routine, specified in
OpenMP 5.0.

GOMP_DEVICE_NUM_VAR is a macro symbol which defines name of a "device number"
variable, is defined on the device-side libgomp, has it's address returned to
host-side libgomp during device initialization, and the host libgomp then
sets its value to the designated device number.

libgomp/ChangeLog:

	* icv-device.c (omp_get_device_num): New API function, host side.
	* fortran.c (omp_get_device_num_): New interface function.
	* libgomp-plugin.h (GOMP_DEVICE_NUM_VAR): Define macro symbol.
	* libgomp.map (OMP_5.0.2): New version space with omp_get_device_num,
	omp_get_device_num_.
	* libgomp.texi (omp_get_device_num): Add documentation for new API
	function.
	* omp.h.in (omp_get_device_num): Add declaration.
	* omp_lib.f90.in (omp_get_device_num): Likewise.
	* omp_lib.h.in (omp_get_device_num): Likewise.
	* target.c (gomp_load_image_to_device): If additional entry for device
	number exists at end of returned entries from 'load_image_func' hook,
	copy the assigned device number over to the device variable.

	* config/gcn/icv-device.c (GOMP_DEVICE_NUM_VAR): Define static global.
	(omp_get_device_num): New API function, device side.
	* plugin/plugin-gcn.c ("symcat.h"): Add include.
	(GOMP_OFFLOAD_load_image): Add addresses of device GOMP_DEVICE_NUM_VAR
	at end of returned 'target_table' entries.

	* config/nvptx/icv-device.c (GOMP_DEVICE_NUM_VAR): Define static global.
	(omp_get_device_num): New API function, device side.
	* plugin/plugin-nvptx.c ("symcat.h"): Add include.
	(GOMP_OFFLOAD_load_image): Add addresses of device GOMP_DEVICE_NUM_VAR
	at end of returned 'target_table' entries.

	* testsuite/lib/libgomp.exp
	(check_effective_target_offload_target_intelmic): New function for
	testing for intelmic offloading.
	* testsuite/libgomp.c-c++-common/target-45.c: New test.
	* testsuite/libgomp.fortran/target10.f90: New test.

2 files changed, 22 insertions, 0 deletions

diff --git a/libgomp/config/gcn/icv-device.c b/libgomp/config/gcn/icv-device.c
index 72d4f7c..34e0f83 100644
--- a/libgomp/config/gcn/icv-device.c
+++ b/libgomp/config/gcn/icv-device.c
@@ -70,6 +70,16 @@ omp_is_initial_device (void)
   return 0;
 }
 
+/* This is set to the device number of current GPU during device initialization,
+   when the offload image containing this libgomp portion is loaded.  */
+static volatile int GOMP_DEVICE_NUM_VAR;
+
+int
+omp_get_device_num (void)
+{
+  return GOMP_DEVICE_NUM_VAR;
+}
+
 ialias (omp_set_default_device)
 ialias (omp_get_default_device)
 ialias (omp_get_initial_device)
@@ -77,3 +87,4 @@ ialias (omp_get_num_devices)
 ialias (omp_get_num_teams)
 ialias (omp_get_team_num)
 ialias (omp_is_initial_device)
+ialias (omp_get_device_num)
diff --git a/libgomp/config/nvptx/icv-device.c b/libgomp/config/nvptx/icv-device.c
index 3b96890..b63149d 100644
--- a/libgomp/config/nvptx/icv-device.c
+++ b/libgomp/config/nvptx/icv-device.c
@@ -58,8 +58,19 @@ omp_is_initial_device (void)
   return 0;
 }
 
+/* This is set to the device number of current GPU during device initialization,
+   when the offload image containing this libgomp portion is loaded.  */
+static volatile int GOMP_DEVICE_NUM_VAR;
+
+int
+omp_get_device_num (void)
+{
+  return GOMP_DEVICE_NUM_VAR;
+}
+
 ialias (omp_set_default_device)
 ialias (omp_get_default_device)
 ialias (omp_get_initial_device)
 ialias (omp_get_num_devices)
 ialias (omp_is_initial_device)
+ialias (omp_get_device_num)