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.

1 files changed, 6 insertions, 0 deletions

diff --git a/libgomp/libgomp-plugin.h b/libgomp/libgomp-plugin.h
index 62645ce9954..cf24a2bee41 100644
--- a/libgomp/libgomp-plugin.h
+++ b/libgomp/libgomp-plugin.h
@@ -102,6 +102,12 @@ struct addr_pair
   uintptr_t end;
 };
 
+/* This symbol is to name a target side variable that holds the designated
+   'device number' of the target device. The symbol needs to be available to
+   libgomp code and the offload plugin (which in the latter case must be
+   stringified).  */
+#define GOMP_DEVICE_NUM_VAR __gomp_device_num
+
 /* Miscellaneous functions.  */
 extern void *GOMP_PLUGIN_malloc (size_t) __attribute__ ((malloc));
 extern void *GOMP_PLUGIN_malloc_cleared (size_t) __attribute__ ((malloc));