[OpenMP][libomptarget] make omp_get_initial_device 5.1 compliant

[protze.joachim]

Summary

OpenMP 5.1 defines omp_get_initial_device to return the same value as omp_get_num_devices.

Since this change is also 5.0 compliant, no versioning is needed.

[protze.joachim]

Removed accidently added printf from a test.

[grokos]

openmp/runtime/src/kmp.h

3879

So we can also remove the HOST_DEVICE macro from openmp/libomptarget/include/omptarget.h:24.

[RaviNarayanaswamy]

Can you also remove the definition in the header file include/omptarget.h

#define HOST_DEVICE -10

[protze.joachim]

Removed HOST_DEVICE definition from the header as suggested in the reviews.

[jdoerfert]

LGTM, one nit. Give @grokos and @RaviNarayanaswamy some time to comment or accept as well.

openmp/runtime/src/kmp_ftn_entry.h

969

Nit: Please put the comments in the line before, also below.

[RaviNarayanaswamy]

LGTM

[grokos]

LGTM as well.

openmp/libomptarget/src/api.cpp

EXTERN int omp_get_num_devices(void) {
   RTLsMtx->unlock();
 
   DP("Call to omp_get_num_devices returning %zd\n", Devices_size);
 
   return Devices_size;
 }
 
 EXTERN int omp_get_initial_device(void) {
-  DP("Call to omp_get_initial_device returning %d\n", HOST_DEVICE);
-  return HOST_DEVICE;
+  int hostDevice = omp_get_num_devices();
+  DP("Call to omp_get_initial_device returning %d\n", hostDevice);
+  return hostDevice;
 }
 
 EXTERN void *omp_target_alloc(size_t size, int device_num) {
   DP("Call to omp_target_alloc for device %d requesting %zu bytes\n",
       device_num, size);
 
   if (size <= 0) {
     DP("Call to omp_target_alloc with non-positive length\n");

openmp/runtime/src/kmp.h

 };
 typedef enum kmp_target_offload_kind kmp_target_offload_kind_t;
 // Set via OMP_TARGET_OFFLOAD if specified, defaults to tgt_default otherwise
 extern kmp_target_offload_kind_t __kmp_target_offload;
 extern int __kmpc_get_target_offload();
 
 // Constants used in libomptarget
 #define KMP_DEVICE_DEFAULT -1 // This is libomptarget's default device.
-#define KMP_HOST_DEVICE -10 // This is what it is in libomptarget, go figure.
 #define KMP_DEVICE_ALL -11 // This is libomptarget's "all devices".
 
 // OMP Pause Resource
 
 // The following enum is used both to set the status in __kmp_pause_status, and
 // as the internal equivalent of the externally-visible omp_pause_resource_t.
 typedef enum kmp_pause_status_t {
   kmp_not_paused = 0, // status is not paused, or, requesting resume

openmp/runtime/src/kmp_ftn_entry.h

 int FTN_STDCALL KMP_EXPAND_NAME(FTN_IS_INITIAL_DEVICE)(void) {
   return 1; // This is the host
 }
 
 // libomptarget, if loaded, provides this function
 int FTN_STDCALL FTN_GET_INITIAL_DEVICE(void) KMP_WEAK_ATTRIBUTE_EXTERNAL;
 int FTN_STDCALL FTN_GET_INITIAL_DEVICE(void) {
 #if KMP_MIC || KMP_OS_DARWIN || KMP_OS_WINDOWS || defined(KMP_STUB)
-  return KMP_HOST_DEVICE;
+  return 0; // omp_get_num_devices()
 #else
   int (*fptr)();
   if ((*(void **)(&fptr) = dlsym(RTLD_NEXT, "omp_get_initial_device"))) {
     return (*fptr)();
   } else { // liboffload & libomptarget don't exist
-    return KMP_HOST_DEVICE;
+    return 0; // omp_get_num_devices()
   }
 #endif
 }
 
 #if defined(KMP_STUB)
 // Entries for stubs library
 // As all *target* functions are C-only parameters always passed by value
 void *FTN_STDCALL FTN_TARGET_ALLOC(size_t size, int device_num) { return 0; }
#else
   return __kmp_max_task_priority;
 #endif
 }
 
 // This function will be defined in libomptarget. When libomptarget is not
 // loaded, we assume we are on the host and return KMP_HOST_DEVICE.
 // Compiler/libomptarget will handle this if called inside target.
 int FTN_STDCALL FTN_GET_DEVICE_NUM(void) KMP_WEAK_ATTRIBUTE_EXTERNAL;
-int FTN_STDCALL FTN_GET_DEVICE_NUM(void) { return KMP_HOST_DEVICE; }
+int FTN_STDCALL FTN_GET_DEVICE_NUM(void) { return FTN_GET_INITIAL_DEVICE(); }
 
 // Compiler will ensure that this is only called from host in sequential region
 int FTN_STDCALL FTN_PAUSE_RESOURCE(kmp_pause_status_t kind, int device_num) {
 #ifdef KMP_STUB
   return 1; // just fail
 #else
-  if (device_num == KMP_HOST_DEVICE)
+  if (device_num == FTN_GET_INITIAL_DEVICE())
     return __kmpc_pause_resource(kind);
   else {
 #if !KMP_OS_WINDOWS
     int (*fptr)(kmp_pause_status_t, int);
     if ((*(void **)(&fptr) = dlsym(RTLD_DEFAULT, "tgt_pause_resource")))
       return (*fptr)(kind, device_num);
     else
 #endif