[OpenMP][OMPT] Introduce a guard to handle OMPT return address

[protze.joachim]

Summary

This is an alternative approach to address inconsistencies pointed out in: D90078
This patch makes sure that the return address is reset, when leaving the scope.
In some cases, I had to move the macro out of an if-statement to have it in the right scope, in some cases I added an additional block to restrict the scope.

This patch does not handle inconsistencies, which might occur if the return address is still set when we call into the application.

In general, I would prefer to pass the address down the stack as function arguments, which is not possible with all the internal calls to external API functions

[hbae]

Looks good to me for the issue I am concerning about. Here is a test that passes with this patch.

repeated_calls.c3 KBDownload

[mstorsjo]

This broke building with OMPT disabled, but I went ahead and pushed a fix for that in 6b429668ded1aa7de4d586fc6dc8a469799b4d9c, by moving OmptReturnAddressGuard to inside the OMPT_SUPPORT ifdef.

[protze.joachim]

In D91692#2417797, @mstorsjo wrote:

This broke building with OMPT disabled, but I went ahead and pushed a fix for that in 6b429668ded1aa7de4d586fc6dc8a469799b4d9c, by moving OmptReturnAddressGuard to inside the OMPT_SUPPORT ifdef.

Thanks!
This reminds me to include a no-OMPT test pass into my pre-push tests.

openmp/runtime/src/kmp_csupport.cpp

if (ompt_enabled.enabled) {
       if (lwt)
         ompt_frame = &(lwt->ompt_task_info.frame);
       else {
         int tid = __kmp_tid_from_gtid(gtid);
         ompt_frame = &(
             parent_team->t.t_implicit_task_taskdata[tid].ompt_task_info.frame);
       }
       ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-      OMPT_STORE_RETURN_ADDRESS(gtid);
     }
+    OMPT_STORE_RETURN_ADDRESS(gtid);
 #endif
 
 #if INCLUDE_SSC_MARKS
     SSC_MARK_FORKING();
 #endif
     __kmp_fork_call(loc, gtid, fork_context_intel, argc,
                     VOLATILE_CAST(microtask_t) microtask, // "wrapped" task
                     VOLATILE_CAST(launch_t) __kmp_invoke_task_func,
void __kmpc_barrier(ident_t *loc, kmp_int32 global_tid) {
   }
 
 #if OMPT_SUPPORT
   ompt_frame_t *ompt_frame;
   if (ompt_enabled.enabled) {
     __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
     if (ompt_frame->enter_frame.ptr == NULL)
       ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-    OMPT_STORE_RETURN_ADDRESS(global_tid);
   }
+  OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
   __kmp_threads[global_tid]->th.th_ident = loc;
   // TODO: explicit barrier_wait_id:
   //   this function is called when 'barrier' directive is present or
   //   implicit barrier at the end of a worksharing construct.
   // 1) better to add a per-thread barrier counter to a thread data structure
   // 2) set to 0 when a new team is created
   // 4) no sync is required

 #endif /* USE_ITT_BUILD */
 
   th = __kmp_threads[gtid];
 
 #if OMPT_SUPPORT && OMPT_OPTIONAL
   kmp_team_t *team;
   ompt_wait_id_t lck;
   void *codeptr_ra;
-  if (ompt_enabled.enabled) {
-    OMPT_STORE_RETURN_ADDRESS(gtid);
+  if (ompt_enabled.enabled) {
     team = __kmp_team_from_gtid(gtid);
     lck = (ompt_wait_id_t)(uintptr_t)&team->t.t_ordered.dt.t_value;
     /* OMPT state update */
     th->th.ompt_thread_info.wait_id = lck;
     th->th.ompt_thread_info.state = ompt_state_wait_ordered;
 
     /* OMPT event callback */
     codeptr_ra = OMPT_LOAD_RETURN_ADDRESS(gtid);
if (__kmp_env_consistency_check)
     __kmp_check_barrier(global_tid, ct_barrier, loc);
 
 #if OMPT_SUPPORT
   ompt_frame_t *ompt_frame;
   if (ompt_enabled.enabled) {
     __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
     if (ompt_frame->enter_frame.ptr == NULL)
       ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-    OMPT_STORE_RETURN_ADDRESS(global_tid);
   }
+  OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 #if USE_ITT_NOTIFY
   __kmp_threads[global_tid]->th.th_ident = loc;
 #endif
   status = __kmp_barrier(bs_plain_barrier, global_tid, TRUE, 0, NULL, NULL);
 #if OMPT_SUPPORT && OMPT_OPTIONAL
   if (ompt_enabled.enabled) {
     ompt_frame->enter_frame = ompt_data_none;
kmp_int32 __kmpc_barrier_master_nowait(ident_t *loc, kmp_int32 global_tid) {
   }
 
 #if OMPT_SUPPORT
   ompt_frame_t *ompt_frame;
   if (ompt_enabled.enabled) {
     __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
     if (ompt_frame->enter_frame.ptr == NULL)
       ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-    OMPT_STORE_RETURN_ADDRESS(global_tid);
   }
+  OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 #if USE_ITT_NOTIFY
   __kmp_threads[global_tid]->th.th_ident = loc;
 #endif
   __kmp_barrier(bs_plain_barrier, global_tid, FALSE, 0, NULL, NULL);
 #if OMPT_SUPPORT && OMPT_OPTIONAL
   if (ompt_enabled.enabled) {
     ompt_frame->enter_frame = ompt_data_none;
if (didit)
     *data_ptr = cpy_data;
 
 #if OMPT_SUPPORT
   ompt_frame_t *ompt_frame;
   if (ompt_enabled.enabled) {
     __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
     if (ompt_frame->enter_frame.ptr == NULL)
       ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-    OMPT_STORE_RETURN_ADDRESS(gtid);
   }
+  OMPT_STORE_RETURN_ADDRESS(gtid);
 #endif
 /* This barrier is not a barrier region boundary */
 #if USE_ITT_NOTIFY
   __kmp_threads[gtid]->th.th_ident = loc;
 #endif
   __kmp_barrier(bs_plain_barrier, gtid, FALSE, 0, NULL, NULL);
 
   if (!didit)
     (*cpy_func)(cpy_data, *data_ptr);
 
 // Consider next barrier a user-visible barrier for barrier region boundaries
 // Nesting checks are already handled by the single construct checks
-
+  {
 #if OMPT_SUPPORT
-  if (ompt_enabled.enabled) {
     OMPT_STORE_RETURN_ADDRESS(gtid);
-  }
 #endif
 #if USE_ITT_NOTIFY
   __kmp_threads[gtid]->th.th_ident = loc; // TODO: check if it is needed (e.g.
 // tasks can overwrite the location)
 #endif
   __kmp_barrier(bs_plain_barrier, gtid, FALSE, 0, NULL, NULL);
 #if OMPT_SUPPORT && OMPT_OPTIONAL
   if (ompt_enabled.enabled) {
     ompt_frame->enter_frame = ompt_data_none;
   }
 #endif
   }
+}
 
 /* -------------------------------------------------------------------------- */
 
 #define INIT_LOCK __kmp_init_user_lock_with_checks
 #define INIT_NESTED_LOCK __kmp_init_nested_user_lock_with_checks
 #define ACQUIRE_LOCK __kmp_acquire_user_lock_with_checks
 #define ACQUIRE_LOCK_TIMED __kmp_acquire_user_lock_with_checks_timed
 #define ACQUIRE_NESTED_LOCK __kmp_acquire_nested_user_lock_with_checks
#if OMPT_SUPPORT
     // JP: as long as there is a barrier in the implementation, OMPT should and
     // will provide the barrier events
     //         so we set-up the necessary frame/return addresses.
     ompt_frame_t *ompt_frame;
     if (ompt_enabled.enabled) {
       __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
       if (ompt_frame->enter_frame.ptr == NULL)
         ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-      OMPT_STORE_RETURN_ADDRESS(global_tid);
     }
+    OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 #if USE_ITT_NOTIFY
     __kmp_threads[global_tid]->th.th_ident = loc;
 #endif
     retval =
         __kmp_barrier(UNPACK_REDUCTION_BARRIER(packed_reduction_method),
                       global_tid, FALSE, reduce_size, reduce_data, reduce_func);
     retval = (retval != 0) ? (0) : (1);

 // this barrier should be visible to a customer and to the threading profile
 // tool (it's a terminating barrier on constructs if NOWAIT not specified)
 #if OMPT_SUPPORT
     ompt_frame_t *ompt_frame;
     if (ompt_enabled.enabled) {
       __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
       if (ompt_frame->enter_frame.ptr == NULL)
         ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-      OMPT_STORE_RETURN_ADDRESS(global_tid);
     }
+    OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 #if USE_ITT_NOTIFY
     __kmp_threads[global_tid]->th.th_ident =
         loc; // needed for correct notification of frames
 #endif
     retval =
         __kmp_barrier(UNPACK_REDUCTION_BARRIER(packed_reduction_method),
                       global_tid, TRUE, reduce_size, reduce_data, reduce_func);

 
 // TODO: implicit barrier: should be exposed
 #if OMPT_SUPPORT
     ompt_frame_t *ompt_frame;
     if (ompt_enabled.enabled) {
       __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
       if (ompt_frame->enter_frame.ptr == NULL)
         ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-      OMPT_STORE_RETURN_ADDRESS(global_tid);
     }
+    OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 #if USE_ITT_NOTIFY
     __kmp_threads[global_tid]->th.th_ident = loc;
 #endif
     __kmp_barrier(bs_plain_barrier, global_tid, FALSE, 0, NULL, NULL);
 #if OMPT_SUPPORT && OMPT_OPTIONAL
     if (ompt_enabled.enabled) {
       ompt_frame->enter_frame = ompt_data_none;
     }
 #endif
 
   } else if (packed_reduction_method == empty_reduce_block) {
 
     OMPT_REDUCTION_END;
 
 // usage: if team size==1, no synchronization is required (Intel platforms only)
 
 // TODO: implicit barrier: should be exposed
 #if OMPT_SUPPORT
     ompt_frame_t *ompt_frame;
     if (ompt_enabled.enabled) {
       __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
       if (ompt_frame->enter_frame.ptr == NULL)
         ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-      OMPT_STORE_RETURN_ADDRESS(global_tid);
     }
+    OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 #if USE_ITT_NOTIFY
     __kmp_threads[global_tid]->th.th_ident = loc;
 #endif
     __kmp_barrier(bs_plain_barrier, global_tid, FALSE, 0, NULL, NULL);
 #if OMPT_SUPPORT && OMPT_OPTIONAL
     if (ompt_enabled.enabled) {
       ompt_frame->enter_frame = ompt_data_none;
     }
 #endif
 
   } else if (packed_reduction_method == atomic_reduce_block) {
 
 #if OMPT_SUPPORT
     ompt_frame_t *ompt_frame;
     if (ompt_enabled.enabled) {
       __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
       if (ompt_frame->enter_frame.ptr == NULL)
         ompt_frame->enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
-      OMPT_STORE_RETURN_ADDRESS(global_tid);
     }
+    OMPT_STORE_RETURN_ADDRESS(global_tid);
 #endif
 // TODO: implicit barrier: should be exposed
 #if USE_ITT_NOTIFY
     __kmp_threads[global_tid]->th.th_ident = loc;
 #endif
     __kmp_barrier(bs_plain_barrier, global_tid, FALSE, 0, NULL, NULL);
 #if OMPT_SUPPORT && OMPT_OPTIONAL
     if (ompt_enabled.enabled) {

openmp/runtime/src/kmp_gsupport.cpp

int func(long lb, long ub, long str, long chunk_sz, long *p_lb,              \
     MKLOC(loc, KMP_STR(func));                                                 \
     KA_TRACE(                                                                  \
         20,                                                                    \
         (KMP_STR(                                                              \
              func) ": T#%d, lb 0x%lx, ub 0x%lx, str 0x%lx, chunk_sz 0x%lx\n",  \
          gtid, lb, ub, str, chunk_sz));                                        \
                                                                                \
     if ((str > 0) ? (lb < ub) : (lb > ub)) {                                   \
-      IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                        \
-      KMP_DISPATCH_INIT(&loc, gtid, (schedule), lb,                            \
-                        (str > 0) ? (ub - 1) : (ub + 1), str, chunk_sz,        \
-                        (schedule) != kmp_sch_static);                         \
-      IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                        \
-      status = KMP_DISPATCH_NEXT(&loc, gtid, NULL, (kmp_int *)p_lb,            \
-                                 (kmp_int *)p_ub, (kmp_int *)&stride);         \
+      {                                                                        \
+        IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                      \
+        KMP_DISPATCH_INIT(&loc, gtid, (schedule), lb,                          \
+                          (str > 0) ? (ub - 1) : (ub + 1), str, chunk_sz,      \
+                          (schedule) != kmp_sch_static);                       \
+      }                                                                        \
+      {                                                                        \
+        IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                      \
+        status = KMP_DISPATCH_NEXT(&loc, gtid, NULL, (kmp_int *)p_lb,          \
+                                   (kmp_int *)p_ub, (kmp_int *)&stride);       \
+      }                                                                        \
       if (status) {                                                            \
         KMP_DEBUG_ASSERT(stride == str);                                       \
         *p_ub += (str > 0) ? 1 : -1;                                           \
       }                                                                        \
     } else {                                                                   \
       status = 0;                                                              \
     }                                                                          \
                                                                                \
int func(long lb, long ub, long str, long *p_lb, long *p_ub) {               \
     int gtid = __kmp_entry_gtid();                                             \
     MKLOC(loc, KMP_STR(func));                                                 \
     KA_TRACE(                                                                  \
         20,                                                                    \
         (KMP_STR(func) ": T#%d, lb 0x%lx, ub 0x%lx, str 0x%lx, chunk_sz %d\n", \
          gtid, lb, ub, str, chunk_sz));                                        \
                                                                                \
     if ((str > 0) ? (lb < ub) : (lb > ub)) {                                   \
-      IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                        \
-      KMP_DISPATCH_INIT(&loc, gtid, (schedule), lb,                            \
-                        (str > 0) ? (ub - 1) : (ub + 1), str, chunk_sz, TRUE); \
-      IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                        \
-      status = KMP_DISPATCH_NEXT(&loc, gtid, NULL, (kmp_int *)p_lb,            \
-                                 (kmp_int *)p_ub, (kmp_int *)&stride);         \
+      {                                                                        \
+        IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                      \
+        KMP_DISPATCH_INIT(&loc, gtid, (schedule), lb,                          \
+                          (str > 0) ? (ub - 1) : (ub + 1), str, chunk_sz,      \
+                          TRUE);                                               \
+      }                                                                        \
+      {                                                                        \
+        IF_OMPT_SUPPORT(OMPT_STORE_RETURN_ADDRESS(gtid);)                      \
+        status = KMP_DISPATCH_NEXT(&loc, gtid, NULL, (kmp_int *)p_lb,          \
+                                   (kmp_int *)p_ub, (kmp_int *)&stride);       \
+      }                                                                        \
       if (status) {                                                            \
         KMP_DEBUG_ASSERT(stride == str);                                       \
         *p_ub += (str > 0) ? 1 : -1;                                           \
       }                                                                        \
     } else {                                                                   \
       status = 0;                                                              \
     }                                                                          \
                                                                                \
#if OMPT_SUPPORT
   OMPT_STORE_RETURN_ADDRESS(gtid);
 #endif
 
   __kmp_GOMP_fork_call(&loc, gtid, num_threads, flags, task,
                        (microtask_t)__kmp_GOMP_parallel_microtask_wrapper, 9,
                        task, data, num_threads, &loc, kmp_nm_dynamic_chunked,
                        (kmp_int)1, (kmp_int)count, (kmp_int)1, (kmp_int)1);
 
+  {
 #if OMPT_SUPPORT
   OMPT_STORE_RETURN_ADDRESS(gtid);
 #endif
 
   KMP_DISPATCH_INIT(&loc, gtid, kmp_nm_dynamic_chunked, 1, count, 1, 1, TRUE);
-
+  }
   task(data);
   KMP_EXPAND_NAME(KMP_API_NAME_GOMP_PARALLEL_END)();
   KA_TRACE(20, ("GOMP_parallel_sections exit: T#%d\n", gtid));
 }
 
 #define PARALLEL_LOOP(func, schedule, ompt_pre, ompt_post)                     \
   void func(void (*task)(void *), void *data, unsigned num_threads, long lb,   \
             long ub, long str, long chunk_sz, unsigned flags) {                \

openmp/runtime/src/ompt-specific.h

 
 inline void *__ompt_load_return_address(int gtid) {
   kmp_info_t *thr = __kmp_threads[gtid];
   void *return_address = thr->th.ompt_thread_info.return_address;
   thr->th.ompt_thread_info.return_address = NULL;
   return return_address;
 }
 
-#define OMPT_STORE_RETURN_ADDRESS(gtid)                                        \
+/*#define OMPT_STORE_RETURN_ADDRESS(gtid) \
   if (ompt_enabled.enabled && gtid >= 0 && __kmp_threads[gtid] &&              \
       !__kmp_threads[gtid]->th.ompt_thread_info.return_address)                \
   __kmp_threads[gtid]->th.ompt_thread_info.return_address =                    \
-      __builtin_return_address(0)
+      __builtin_return_address(0)*/
+#define OMPT_STORE_RETURN_ADDRESS(gtid)                                        \
+  OmptReturnAddressGuard ReturnAddressGuard{gtid, __builtin_return_address(0)};
 #define OMPT_LOAD_RETURN_ADDRESS(gtid) __ompt_load_return_address(gtid)
 #define OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid)                                  \
   ((ompt_enabled.enabled && gtid >= 0 && __kmp_threads[gtid] &&                \
       __kmp_threads[gtid]->th.ompt_thread_info.return_address)?                \
       __ompt_load_return_address(gtid):                                        \
       __builtin_return_address(0))
 
 //******************************************************************************
ompt_callbacks.ompt_callback(ompt_callback_reduction)(                     \
         my_task_data, return_address);                                         \
   }
 #else // OMPT_SUPPORT && OMPT_OPTIONAL
 #define OMPT_REDUCTION_DECL(this_thr, gtid)
 #define OMPT_REDUCTION_BEGIN
 #define OMPT_REDUCTION_END
 #endif // ! OMPT_SUPPORT && OMPT_OPTIONAL
 
+class OmptReturnAddressGuard {
+private:
+  bool SetAddress{false};
+  int Gtid;
+
+public:
+  OmptReturnAddressGuard(int Gtid, void *ReturnAddress) : Gtid(Gtid) {
+    if (ompt_enabled.enabled && Gtid >= 0 && __kmp_threads[Gtid] &&
+        !__kmp_threads[Gtid]->th.ompt_thread_info.return_address) {
+      SetAddress = true;
+      __kmp_threads[Gtid]->th.ompt_thread_info.return_address = ReturnAddress;
+    }
+  }
+  ~OmptReturnAddressGuard() {
+    if (SetAddress)
+      __kmp_threads[Gtid]->th.ompt_thread_info.return_address = NULL;
+  }
+};
+
 #endif

openmp/runtime/test/ompt/parallel/repeated_calls.c

+// RUN: %libomp-compile-and-run | FileCheck %s
+// REQUIRES: ompt
+
+#define USE_PRIVATE_TOOL 1
+#include "callback.h"
+
+__attribute__((noinline))
+int foo(int x) {
+#pragma omp parallel num_threads(2)
+  {
+#pragma omp atomic
+    x++;
+  }
+  return x;
+}
+
+__attribute__((noinline))
+int bar(int x) {
+#pragma omp parallel num_threads(2)
+  {
+#pragma omp critical
+    x++;
+  }
+  return x;
+}
+
+int main() {
+  int y;
+  y = foo(y);
+  y = bar(y);
+  y = foo(y);
+  return 0;
+
+  // CHECK-NOT: {{^}}0: Could not register callback
+  // CHECK: 0: NULL_POINTER=[[NULL:.*$]]
+
+  // First call to foo
+  // CHECK: {{^}}[[MASTER_ID:[0-9]+]]: ompt_event_parallel_begin
+  // CHECK-SAME: {{.*}}codeptr_ra=[[RETURN_ADDRESS:0x[0-f]+]]
+
+  // Call to bar
+  // CHECK: {{^}}[[MASTER_ID]]: ompt_event_parallel_begin
+
+  // Second call to foo
+  // CHECK: {{^}}[[MASTER_ID]]: ompt_event_parallel_begin
+  // CHECK-SAME: {{.*}}codeptr_ra=[[RETURN_ADDRESS]]
+
+}
+
+static void on_ompt_callback_thread_begin(
+    ompt_thread_t thread_type,
+    ompt_data_t *thread_data) {
+  if (thread_data->ptr)
+    printf("%s\n", "0: thread_data initially not null");
+  thread_data->value = ompt_get_unique_id();
+  printf("%" PRIu64 ":" _TOOL_PREFIX
+         " ompt_event_thread_begin: thread_type=%s=%d, thread_id=%" PRIu64 "\n",
+         ompt_get_thread_data()->value, ompt_thread_t_values[thread_type],
+         thread_type, thread_data->value);
+}
+
+static void on_ompt_callback_parallel_begin(
+    ompt_data_t *encountering_task_data,
+    const ompt_frame_t *encountering_task_frame, ompt_data_t *parallel_data,
+    uint32_t requested_team_size, int flag, const void *codeptr_ra) {
+  if (parallel_data->ptr)
+    printf("0: parallel_data initially not null\n");
+  parallel_data->value = ompt_get_unique_id();
+  int invoker = flag & 0xF;
+  const char *event = (flag & ompt_parallel_team) ? "parallel" : "teams";
+  const char *size = (flag & ompt_parallel_team) ? "team_size" : "num_teams";
+  printf("%" PRIu64 ":" _TOOL_PREFIX
+         " ompt_event_%s_begin: parent_task_id=%" PRIu64
+         ", parent_task_frame.exit=%p, parent_task_frame.reenter=%p, "
+         "parallel_id=%" PRIu64 ", requested_%s=%" PRIu32
+         ", codeptr_ra=%p, invoker=%d\n",
+         ompt_get_thread_data()->value, event, encountering_task_data->value,
+         encountering_task_frame->exit_frame.ptr,
+         encountering_task_frame->enter_frame.ptr, parallel_data->value, size,
+         requested_team_size, codeptr_ra, invoker);
+}
+
+int ompt_initialize(ompt_function_lookup_t lookup, int initial_device_num,
+                    ompt_data_t *tool_data) {
+  ompt_set_callback = (ompt_set_callback_t)lookup("ompt_set_callback");
+  ompt_get_unique_id = (ompt_get_unique_id_t)lookup("ompt_get_unique_id");
+  ompt_get_thread_data = (ompt_get_thread_data_t)lookup("ompt_get_thread_data");
+
+  register_callback(ompt_callback_thread_begin);
+  register_callback(ompt_callback_parallel_begin);
+  printf("0: NULL_POINTER=%p\n", (void *)NULL);
+  return 1; // success
+}
+
+void ompt_finalize(ompt_data_t *tool_data) {}
+
+ompt_start_tool_result_t *ompt_start_tool(unsigned int omp_version,
+                                          const char *runtime_version) {
+  static ompt_start_tool_result_t ompt_start_tool_result = {&ompt_initialize,
+                                                            &ompt_finalize, 0};
+  return &ompt_start_tool_result;
+}