[Openmp-commits] [PATCH] D149557: [OpenMP] Handle function calls from `libomp` to `libomptarget` correctly

[Shilei Tian via Phabricator via Openmp-commits]

tianshilei1992 created this revision.
tianshilei1992 added reviewers: jdoerfert, AndreyChurbanov, tlwilmar, jlpeyton, natgla.
Herald added subscribers: sunshaoce, guansong, yaxunl.
Herald added a project: All.
tianshilei1992 requested review of this revision.
Herald added subscribers: openmp-commits, jplehr, sstefan1.
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D132005 <https://reviews.llvm.org/D132005> introduced function calls from `libomp` to `libomptarget` if offloading
is enabled. However, the external function declaration may not always work. For
example, it causes a link error on macOS. Currently it is guarded properly by
a macro, but in order to get OpenMP target offloading working on macOS, it has
to be handled correctly. This patch applies the same idea of how we support
target memory extension by using function pointer indirect call for that function.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D149557

Files:
  openmp/runtime/src/kmp.h
  openmp/runtime/src/kmp_runtime.cpp
  openmp/runtime/src/kmp_tasking.cpp


Index: openmp/runtime/src/kmp_tasking.cpp
===================================================================
--- openmp/runtime/src/kmp_tasking.cpp
+++ openmp/runtime/src/kmp_tasking.cpp
@@ -22,8 +22,11 @@
 #endif
 
 #if ENABLE_LIBOMPTARGET
-// Declaration of synchronization function from libomptarget.
-extern "C" void __tgt_target_nowait_query(void **) KMP_WEAK_ATTRIBUTE_INTERNAL;
+static void (*tgt_target_nowait_query)(void **);
+
+void __kmp_init_target_task() {
+  *(void **)(&tgt_target_nowait_query) = KMP_DLSYM("__tgt_target_nowait_query");
+}
 #endif
 
 /* forward declaration */
@@ -1805,7 +1808,7 @@
       // 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);
+      tgt_target_nowait_query(&taskdata->td_target_data.async_handle);
     } else
 #endif
     if (task->routine != NULL) {
Index: openmp/runtime/src/kmp_runtime.cpp
===================================================================
--- openmp/runtime/src/kmp_runtime.cpp
+++ openmp/runtime/src/kmp_runtime.cpp
@@ -553,6 +553,14 @@
 
 /* ------------------------------------------------------------------------ */
 
+#if ENABLE_LIBOMPTARGET
+static void __kmp_init_omptarget() {
+  __kmp_init_target_task();
+}
+#endif
+
+/* ------------------------------------------------------------------------ */
+
 #if KMP_DYNAMIC_LIB
 #if KMP_OS_WINDOWS
 
@@ -7041,6 +7049,11 @@
 
   __kmp_validate_locks();
 
+#if ENABLE_LIBOMPTARGET
+  /* Initialize functions from libomptarget */
+  __kmp_init_omptarget();
+#endif
+
   /* Initialize internal memory allocator */
   __kmp_init_allocator();
 
Index: openmp/runtime/src/kmp.h
===================================================================
--- openmp/runtime/src/kmp.h
+++ openmp/runtime/src/kmp.h
@@ -1100,6 +1100,12 @@
 
 /* ------------------------------------------------------------------------ */
 
+#if ENABLE_LIBOMPTARGET
+extern void __kmp_init_target_task();
+#endif
+
+/* ------------------------------------------------------------------------ */
+
 #define KMP_UINT64_MAX                                                         \
   (~((kmp_uint64)1 << ((sizeof(kmp_uint64) * (1 << 3)) - 1)))
 


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