[OpenMP] Disable libomptarget integration on unsupported platforms

[gValarini]

It's a simple fix that should work, but could someone try compiling it on macOS? I don´t have a mac computer...

[jhuber6]

openmp/runtime/src/kmp_config.h.cmake

97

Is this enough? We need to check the target OS, because even if the user builds on MacOS with libomptarget it won't always be included like if the user just passed -fopenmp.

[gValarini]

openmp/runtime/src/kmp_config.h.cmake

97

If I am not mistaken, that is already checked on the OpenMP CMakeLists.txt file. OPENMP_ENABLE_LIBOMPTARGET can only be set to 1 if the target OS is not either macOS or Windows.

But do you think it would be better to tie that to something like ! (KMP_OS_WINDOWS || KMP_OS_DARWIN)?

[jhuber6]

openmp/runtime/src/kmp_config.h.cmake

97

You're right, forgot we did that check. It'll work for now and I guess we can revisit it if we ever want to lift that restriction.

[gValarini]

openmp/runtime/src/kmp_config.h.cmake

97

Perfect! I'll land it then.

openmp/runtime/src/kmp_config.h.cmake

 #cmakedefine01 LIBOMP_HAVE__MM_MALLOC
 #define KMP_HAVE__MM_MALLOC LIBOMP_HAVE__MM_MALLOC
 #cmakedefine01 LIBOMP_HAVE_ALIGNED_ALLOC
 #define KMP_HAVE_ALIGNED_ALLOC LIBOMP_HAVE_ALIGNED_ALLOC
 #cmakedefine01 LIBOMP_HAVE_POSIX_MEMALIGN
 #define KMP_HAVE_POSIX_MEMALIGN LIBOMP_HAVE_POSIX_MEMALIGN
 #cmakedefine01 LIBOMP_HAVE__ALIGNED_MALLOC
 #define KMP_HAVE__ALIGNED_MALLOC LIBOMP_HAVE__ALIGNED_MALLOC
+#cmakedefine01 OPENMP_ENABLE_LIBOMPTARGET
+#define ENABLE_LIBOMPTARGET OPENMP_ENABLE_LIBOMPTARGET
 
 // Configured cache line based on architecture
 #if KMP_ARCH_PPC64
 # define CACHE_LINE 128
 #elif KMP_ARCH_AARCH64_A64FX
 # define CACHE_LINE 256
 #else
 # define CACHE_LINE 64

openmp/runtime/src/kmp_tasking.cpp

 #include "kmp_stats.h"
 #include "kmp_wait_release.h"
 #include "kmp_taskdeps.h"
 
 #if OMPT_SUPPORT
 #include "ompt-specific.h"
 #endif
 
+#if ENABLE_LIBOMPTARGET
 // Declaration of synchronization function from libomptarget.
 extern "C" void __tgt_target_nowait_query(void **) KMP_WEAK_ATTRIBUTE_INTERNAL;
+#endif
 
 /* forward declaration */
 static void __kmp_enable_tasking(kmp_task_team_t *task_team,
                                  kmp_info_t *this_thr);
 static void __kmp_alloc_task_deque(kmp_info_t *thread,
                                    kmp_thread_data_t *thread_data);
 static int __kmp_realloc_task_threads_data(kmp_info_t *thread,
                                            kmp_task_team_t *task_team);
if (kmp_itt_count_task) {
       if (thread->th.th_bar_arrive_time)
         cur_time = __itt_get_timestamp();
       else
         kmp_itt_count_task = 0; // thread is not on a barrier - skip timing
     }
     KMP_FSYNC_ACQUIRED(taskdata); // acquired self (new task)
 #endif
 
+#if ENABLE_LIBOMPTARGET
     if (taskdata->td_target_data.async_handle != NULL) {
       // If we have a valid target async handle, that means that we have already
       // executed the task routine once. We must query for the handle completion
       // instead of re-executing the routine.
       __tgt_target_nowait_query(&taskdata->td_target_data.async_handle);
-    } else if (task->routine != NULL) {
+    } else
+#endif
+    if (task->routine != NULL) {
 #ifdef KMP_GOMP_COMPAT
       if (taskdata->td_flags.native) {
         ((void (*)(void *))(*(task->routine)))(task->shareds);
       } else
 #endif /* KMP_GOMP_COMPAT */
       {
         (*(task->routine))(gtid, task);
       }