[OpenMP] Implementing omp_get_device_num()

This patch implements omp_get_device_num() in the host and the device.

It uses the already existing getDeviceNum in the device config for the device.
And in the host it uses the omp_get_num_devices().

Two simple tests added

Differential Revision: https://reviews.llvm.org/D128347

openmp/libomptarget/DeviceRTL/include/Configuration.h

@@ -28,8 +28,7 @@ enum DebugKind : uint32_t {
 /// host by omp_get_num_devices.
 uint32_t getNumDevices();
 
-/// Return the number of devices in the system, same number as returned on the
-/// host by omp_get_num_devices.
+/// Return the device number in the system for omp_get_device_num.
 uint32_t getDeviceNum();
 
 /// Return the user choosen debug level.

openmp/libomptarget/DeviceRTL/include/Interface.h

@@ -126,6 +126,8 @@ int omp_get_default_device(void);
 
 int omp_get_num_devices(void);
 
+int omp_get_device_num(void);
+
 int omp_get_num_teams(void);
 
 int omp_get_team_num();

openmp/libomptarget/DeviceRTL/src/State.cpp

@@ -504,6 +504,8 @@ int omp_get_default_device(void) { return -1; }
 
 int omp_get_num_devices(void) { return config::getNumDevices(); }
 
+int omp_get_device_num(void) { return config::getDeviceNum(); }
+
 int omp_get_num_teams(void) { return mapping::getNumberOfBlocks(); }
 
 int omp_get_team_num() { return mapping::getBlockId(); }

openmp/libomptarget/include/omptarget.h

@@ -202,6 +202,7 @@ extern "C" {
 #endif
 
 int omp_get_num_devices(void);
+int omp_get_device_num(void);
 int omp_get_initial_device(void);
 void *omp_target_alloc(size_t size, int device_num);
 void omp_target_free(void *device_ptr, int device_num);

openmp/libomptarget/src/api.cpp

@@ -30,6 +30,15 @@ EXTERN int omp_get_num_devices(void) {
   return DevicesSize;
 }
 
+EXTERN int omp_get_device_num(void) {
+  TIMESCOPE();
+  int HostDevice = omp_get_initial_device();
+
+  DP("Call to omp_get_device_num returning %d\n", HostDevice);
+
+  return HostDevice;
+}
+
 EXTERN int omp_get_initial_device(void) {
   TIMESCOPE();
   int hostDevice = omp_get_num_devices();

openmp/libomptarget/src/exports

@@ -29,6 +29,7 @@ VERS1.0 {
     __kmpc_push_target_tripcount;
     __kmpc_push_target_tripcount_mapper;
     omp_get_num_devices;
+    omp_get_device_num;
     omp_get_initial_device;
     omp_target_alloc;
     omp_target_free;

openmp/libomptarget/test/api/omp_get_device_num.c

@@ -0,0 +1,33 @@
+// RUN: %libomptarget-compile-run-and-check-generic
+
+#include <stdio.h>
+#include <omp.h>
+
+int test_omp_get_device_num()
+{
+  /* checks that omp_get_device_num() == omp_get_num_devices() in the host */
+  int device_num = omp_get_device_num();
+  printf("device_num = %d\n", device_num);
+
+  #pragma omp target
+  {}
+
+  return (device_num == omp_get_num_devices());
+}
+
+int main()
+{
+  int i;
+  int failed=0;
+
+  if (!test_omp_get_device_num()) {
+    failed++;
+  }
+  if (failed)
+    printf("FAIL\n");
+  else
+    printf("PASS\n");
+  return failed;
+}
+
+// CHECK: PASS

openmp/runtime/test/api/omp_get_device_num.c

@@ -0,0 +1,27 @@
+// RUN: %libomp-compile-and-run
+// Linking fails for icc 18
+// UNSUPPORTED: icc-18
+
+#include <stdio.h>
+#include "omp_testsuite.h"
+
+int test_omp_get_device_num()
+{
+  /* checks that omp_get_device_num */
+  int device_num = omp_get_device_num();
+
+  return (device_num == omp_get_num_devices());
+}
+
+int main()
+{
+  int i;
+  int num_failed=0;
+
+  for(i = 0; i < REPETITIONS; i++) {
+    if(!test_omp_get_device_num()) {
+      num_failed++;
+    }
+  }
+  return num_failed;
+}