[OMPT] Cleanup reset of exit_frame pointer

[Hahnfeld]

Summary

This is done at call-site and does not need to be handled in
__kmp_invoke_microtask. It was already absent from the x86
and x86_64 assembly, this patch removes it from the generic
implementation in z_Linux_util.cpp and adds documentation for
AArch64 and PPC64 that it's actually not needed. I can't test
on these architectures, so I don't want to change the code just
because it looks right :)

While at it, rename some variables for consistency and add a
check in test/ompt/parallel/normal.c to check that the pointer
was reset before entering the barrier.

[Hahnfeld]

I also tried to test that the exit_frame is reset for serialized regions, but we don't have an implicit barrier then :-(

openmp/runtime/src/kmp_runtime.cpp

1828

I think this was actually wrong before, but I didn't manage to write a test for this code path.

[Hahnfeld]

ping

[hbae]

Looks good to me.

openmp/runtime/src/kmp_runtime.cpp

#endif
         // AC: we are in serialized parallel
         __kmpc_serialized_parallel(loc, gtid);
         KMP_DEBUG_ASSERT(parent_team->t.t_serialized > 1);
         // AC: need this in order enquiry functions work
         // correctly, will restore at join time
         parent_team->t.t_serialized--;
 #if OMPT_SUPPORT
         void *dummy;
-        void **exit_runtime_p;
+        void **exit_frame_p;
 
         ompt_lw_taskteam_t lw_taskteam;
 
         if (ompt_enabled.enabled) {
           __ompt_lw_taskteam_init(&lw_taskteam, master_th, gtid,
                                   &ompt_parallel_data, return_address);
-          exit_runtime_p = &(lw_taskteam.ompt_task_info.frame.exit_frame.ptr);
+          exit_frame_p = &(lw_taskteam.ompt_task_info.frame.exit_frame.ptr);
 
           __ompt_lw_taskteam_link(&lw_taskteam, master_th, 0);
           // don't use lw_taskteam after linking. content was swaped
 
           /* OMPT implicit task begin */
           implicit_task_data = OMPT_CUR_TASK_DATA(master_th);
           if (ompt_enabled.ompt_callback_implicit_task) {
             ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
                 ompt_scope_begin, OMPT_CUR_TEAM_DATA(master_th),
                 implicit_task_data, 1, __kmp_tid_from_gtid(gtid), ompt_task_implicit); // TODO: Can this be ompt_task_initial?
             OMPT_CUR_TASK_INFO(master_th)
                 ->thread_num = __kmp_tid_from_gtid(gtid);
           }
 
           /* OMPT state */
           master_th->th.ompt_thread_info.state = ompt_state_work_parallel;
         } else {
-          exit_runtime_p = &dummy;
+          exit_frame_p = &dummy;
         }
 #endif
 
         {
           KMP_TIME_PARTITIONED_BLOCK(OMP_parallel);
           KMP_SET_THREAD_STATE_BLOCK(IMPLICIT_TASK);
           __kmp_invoke_microtask(microtask, gtid, 0, argc, parent_team->t.t_argv
 #if OMPT_SUPPORT
                                  ,
-                                 exit_runtime_p
+                                 exit_frame_p
 #endif
                                  );
         }
 
 #if OMPT_SUPPORT
-        *exit_runtime_p = NULL;
         if (ompt_enabled.enabled) {
+          *exit_frame_p = NULL;
           OMPT_CUR_TASK_INFO(master_th)->frame.exit_frame = ompt_data_none;
           if (ompt_enabled.ompt_callback_implicit_task) {
             ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
                 ompt_scope_end, NULL, implicit_task_data, 1,
                 OMPT_CUR_TASK_INFO(master_th)->thread_num, ompt_task_implicit); // TODO: Can this be ompt_task_initial?
           }
           __ompt_lw_taskteam_unlink(master_th);
 

 #if OMP_40_ENABLED
         if (!ap) {
           // revert change made in __kmpc_serialized_parallel()
           master_th->th.th_serial_team->t.t_level--;
 // Get args from parent team for teams construct
 
 #if OMPT_SUPPORT
           void *dummy;
-          void **exit_runtime_p;
+          void **exit_frame_p;
           ompt_task_info_t *task_info;
 
           ompt_lw_taskteam_t lw_taskteam;
 
           if (ompt_enabled.enabled) {
             __ompt_lw_taskteam_init(&lw_taskteam, master_th, gtid,
                                     &ompt_parallel_data, return_address);
 
             __ompt_lw_taskteam_link(&lw_taskteam, master_th, 0);
             // don't use lw_taskteam after linking. content was swaped
 
             task_info = OMPT_CUR_TASK_INFO(master_th);
-            exit_runtime_p = &(task_info->frame.exit_frame.ptr);
+            exit_frame_p = &(task_info->frame.exit_frame.ptr);
             if (ompt_enabled.ompt_callback_implicit_task) {
               ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
                   ompt_scope_begin, OMPT_CUR_TEAM_DATA(master_th),
                   &(task_info->task_data), 1, __kmp_tid_from_gtid(gtid), ompt_task_implicit); // TODO: Can this be ompt_task_initial?
               OMPT_CUR_TASK_INFO(master_th)
                   ->thread_num = __kmp_tid_from_gtid(gtid);
             }
 
             /* OMPT state */
             master_th->th.ompt_thread_info.state = ompt_state_work_parallel;
           } else {
-            exit_runtime_p = &dummy;
+            exit_frame_p = &dummy;
           }
 #endif
 
           {
             KMP_TIME_PARTITIONED_BLOCK(OMP_parallel);
             KMP_SET_THREAD_STATE_BLOCK(IMPLICIT_TASK);
             __kmp_invoke_microtask(microtask, gtid, 0, argc,
                                    parent_team->t.t_argv
 #if OMPT_SUPPORT
                                    ,
-                                   exit_runtime_p
+                                   exit_frame_p
 #endif
                                    );
           }
 
 #if OMPT_SUPPORT
           if (ompt_enabled.enabled) {
-            exit_runtime_p = NULL;
+            *exit_frame_p = NULL;
             if (ompt_enabled.ompt_callback_implicit_task) {
               ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
                   ompt_scope_end, NULL, &(task_info->task_data), 1,
                   OMPT_CUR_TASK_INFO(master_th)->thread_num, ompt_task_implicit); // TODO: Can this be ompt_task_initial?
             }
 
             __ompt_lw_taskteam_unlink(master_th);
             if (ompt_enabled.ompt_callback_parallel_end) {
#if (KMP_ARCH_X86_64 || KMP_ARCH_ARM || KMP_ARCH_AARCH64) && KMP_OS_LINUX
             *argv++ = va_arg(*ap, void *);
 #else
           *argv++ = va_arg(ap, void *);
 #endif
           KMP_MB();
 
 #if OMPT_SUPPORT
           void *dummy;
-          void **exit_runtime_p;
+          void **exit_frame_p;
           ompt_task_info_t *task_info;
 
           ompt_lw_taskteam_t lw_taskteam;
 
           if (ompt_enabled.enabled) {
             __ompt_lw_taskteam_init(&lw_taskteam, master_th, gtid,
                                     &ompt_parallel_data, return_address);
             __ompt_lw_taskteam_link(&lw_taskteam, master_th, 0);
             // don't use lw_taskteam after linking. content was swaped
             task_info = OMPT_CUR_TASK_INFO(master_th);
-            exit_runtime_p = &(task_info->frame.exit_frame.ptr);
+            exit_frame_p = &(task_info->frame.exit_frame.ptr);
 
             /* OMPT implicit task begin */
             implicit_task_data = OMPT_CUR_TASK_DATA(master_th);
             if (ompt_enabled.ompt_callback_implicit_task) {
               ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
                   ompt_scope_begin, OMPT_CUR_TEAM_DATA(master_th),
                   implicit_task_data, 1, __kmp_tid_from_gtid(gtid), ompt_task_implicit); // TODO: Can this be ompt_task_initial?
               OMPT_CUR_TASK_INFO(master_th)
                   ->thread_num = __kmp_tid_from_gtid(gtid);
             }
 
             /* OMPT state */
             master_th->th.ompt_thread_info.state = ompt_state_work_parallel;
           } else {
-            exit_runtime_p = &dummy;
+            exit_frame_p = &dummy;
           }
 #endif
 
           {
             KMP_TIME_PARTITIONED_BLOCK(OMP_parallel);
             KMP_SET_THREAD_STATE_BLOCK(IMPLICIT_TASK);
             __kmp_invoke_microtask(microtask, gtid, 0, argc, args
 #if OMPT_SUPPORT
                                    ,
-                                   exit_runtime_p
+                                   exit_frame_p
 #endif
                                    );
           }
 
 #if OMPT_SUPPORT
           if (ompt_enabled.enabled) {
-            *exit_runtime_p = NULL;
+            *exit_frame_p = NULL;
             if (ompt_enabled.ompt_callback_implicit_task) {
               ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
                   ompt_scope_end, NULL, &(task_info->task_data), 1,
                   OMPT_CUR_TASK_INFO(master_th)->thread_num, ompt_task_implicit); // TODO: Can this be ompt_task_initial?
             }
 
             ompt_parallel_data = *OMPT_CUR_TEAM_DATA(master_th);
             __ompt_lw_taskteam_unlink(master_th);
#if USE_ITT_BUILD
   }
 #endif /* USE_ITT_BUILD */
 #if INCLUDE_SSC_MARKS
   SSC_MARK_INVOKING();
 #endif
 
 #if OMPT_SUPPORT
   void *dummy;
-  void **exit_runtime_p;
+  void **exit_frame_p;
   ompt_data_t *my_task_data;
   ompt_data_t *my_parallel_data;
   int ompt_team_size;
 
   if (ompt_enabled.enabled) {
-    exit_runtime_p = &(
+    exit_frame_p = &(
         team->t.t_implicit_task_taskdata[tid].ompt_task_info.frame.exit_frame.ptr);
   } else {
-    exit_runtime_p = &dummy;
+    exit_frame_p = &dummy;
   }
 
   my_task_data =
       &(team->t.t_implicit_task_taskdata[tid].ompt_task_info.task_data);
   my_parallel_data = &(team->t.ompt_team_info.parallel_data);
   if (ompt_enabled.ompt_callback_implicit_task) {
     ompt_team_size = team->t.t_nproc;
     ompt_callbacks.ompt_callback(ompt_callback_implicit_task)(
#if KMP_STATS_ENABLED
   }
   KMP_SET_THREAD_STATE(IMPLICIT_TASK);
 #endif
 
   rc = __kmp_invoke_microtask((microtask_t)TCR_SYNC_PTR(team->t.t_pkfn), gtid,
                               tid, (int)team->t.t_argc, (void **)team->t.t_argv
 #if OMPT_SUPPORT
                               ,
-                              exit_runtime_p
+                              exit_frame_p
 #endif
                               );
 #if OMPT_SUPPORT
-  *exit_runtime_p = NULL;
+  *exit_frame_p = NULL;
 #endif
 
 #if KMP_STATS_ENABLED
   if (previous_state == stats_state_e::TEAMS_REGION) {
     KMP_SET_THREAD_STATE(previous_state);
   }
   KMP_POP_PARTITIONED_TIMER();
 #endif

openmp/runtime/src/z_Linux_asm.S

// return:  %eax
         popl    %ebp
         ret
 
         DEBUG_INFO __kmp_xchg_real32
 
 # endif /* !KMP_ASM_INTRINS */
 
 //------------------------------------------------------------------------
-// typedef void  (*microtask_t)( int *gtid, int *tid, ... );
-//
 // int
-// __kmp_invoke_microtask( microtask_t pkfn, int gtid, int tid,
-//                         int argc, void *p_argv[] ) {
-//    (*pkfn)( & gtid, & gtid, argv[0], ... );
-//    return 1;
+// __kmp_invoke_microtask( void (*pkfn) (int gtid, int tid, ...),
+//                         int gtid, int tid,
+//                         int argc, void *p_argv[]
+// #if OMPT_SUPPORT
+//                         ,
+//                         void **exit_frame_ptr
+// #endif
+//                       ) {
+// #if OMPT_SUPPORT
+//   *exit_frame_ptr = OMPT_GET_FRAME_ADDRESS(0);
+// #endif
+//
+//   (*pkfn)( & gtid, & tid, argv[0], ... );
+//   return 1;
 // }
 
 // -- Begin __kmp_invoke_microtask
 // mark_begin;
   PROC  __kmp_invoke_microtask
 
   pushl %ebp
   KMP_CFI_DEF_OFFSET 8
movd  %rax, %xmm0 // load old value into return register
         DEBUG_INFO __kmp_xchg_real64
 
 
 # endif /* !KMP_MIC */
 
 # endif /* !KMP_ASM_INTRINS */
 
 //------------------------------------------------------------------------
-// typedef void (*microtask_t)( int *gtid, int *tid, ... );
-//
 // int
 // __kmp_invoke_microtask( void (*pkfn) (int gtid, int tid, ...),
-//               int gtid, int tid,
-//                         int argc, void *p_argv[] ) {
-//    (*pkfn)( & gtid, & tid, argv[0], ... );
-//    return 1;
+//                         int gtid, int tid,
+//                         int argc, void *p_argv[]
+// #if OMPT_SUPPORT
+//                         ,
+//                         void **exit_frame_ptr
+// #endif
+//                       ) {
+// #if OMPT_SUPPORT
+//   *exit_frame_ptr = OMPT_GET_FRAME_ADDRESS(0);
+// #endif
+//
+//   (*pkfn)( & gtid, & tid, argv[0], ... );
+//   return 1;
 // }
 //
 // note: at call to pkfn must have %rsp 128-byte aligned for compiler
 //
 // parameters:
 //      %rdi:   pkfn
 //  %esi: gtid
 //  %edx: tid

 
 // -----------------------------------------------------------------------
 #endif /* KMP_ARCH_X86_64 */
 
 // '
 #if (KMP_OS_LINUX || KMP_OS_DARWIN) && KMP_ARCH_AARCH64
 
 //------------------------------------------------------------------------
-//
-// typedef void (*microtask_t)( int *gtid, int *tid, ... );
-//
 // int
 // __kmp_invoke_microtask( void (*pkfn) (int gtid, int tid, ...),
-//               int gtid, int tid,
-//                         int argc, void *p_argv[] ) {
-//    (*pkfn)( & gtid, & tid, argv[0], ... );
-//    return 1;
+//                         int gtid, int tid,
+//                         int argc, void *p_argv[]
+// #if OMPT_SUPPORT
+//                         ,
+//                         void **exit_frame_ptr
+// #endif
+//                       ) {
+// #if OMPT_SUPPORT
+//   *exit_frame_ptr = OMPT_GET_FRAME_ADDRESS(0);
+// #endif
+//
+//   (*pkfn)( & gtid, & tid, argv[0], ... );
+//
+// // FIXME: This is done at call-site and can be removed here.
+// #if OMPT_SUPPORT
+//   *exit_frame_ptr = 0;
+// #endif
+//
+//   return 1;
 // }
 //
 // parameters:
 //  x0: pkfn
 //  w1: gtid
 //  w2: tid
 //  w3: argc
 //  x4: p_argv
# endif
   DEBUG_INFO __kmp_invoke_microtask
 // -- End  __kmp_invoke_microtask
 
 #endif /* (KMP_OS_LINUX || KMP_OS_DARWIN) && KMP_ARCH_AARCH64 */
 
 #if KMP_ARCH_PPC64
 
 //------------------------------------------------------------------------
-//
-// typedef void (*microtask_t)( int *gtid, int *tid, ... );
-//
 // int
 // __kmp_invoke_microtask( void (*pkfn) (int gtid, int tid, ...),
-//               int gtid, int tid,
-//                         int argc, void *p_argv[] ) {
-//    (*pkfn)( & gtid, & tid, argv[0], ... );
-//    return 1;
+//                         int gtid, int tid,
+//                         int argc, void *p_argv[]
+// #if OMPT_SUPPORT
+//                         ,
+//                         void **exit_frame_ptr
+// #endif
+//                       ) {
+// #if OMPT_SUPPORT
+//   *exit_frame_ptr = OMPT_GET_FRAME_ADDRESS(0);
+// #endif
+//
+//   (*pkfn)( & gtid, & tid, argv[0], ... );
+//
+// // FIXME: This is done at call-site and can be removed here.
+// #if OMPT_SUPPORT
+//   *exit_frame_ptr = 0;
+// #endif
+//
+//   return 1;
 // }
 //
 // parameters:
 //  r3: pkfn
 //  r4: gtid
 //  r5: tid
 //  r6: argc
 //  r7: p_argv

openmp/runtime/src/z_Linux_util.cpp

case 14:
     break;
   case 15:
     (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
             p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
             p_argv[11], p_argv[12], p_argv[13], p_argv[14]);
     break;
   }
 
-#if OMPT_SUPPORT
-  *exit_frame_ptr = 0;
-#endif
-
   return 1;
 }
 
 #endif
 
 // end of file //

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

#pragma omp parallel num_threads(4)
   // THREADS-SAME: parallel_id=[[PARALLEL_ID]], task_id=[[IMPLICIT_TASK_ID]]
   // THREADS: {{^}}[[MASTER_ID]]: task level 1
   // THREADS-SAME: parallel_id=[[IMPLICIT_PARALLEL_ID:[0-9]+]]
   // THREADS-SAME: task_id=[[PARENT_TASK_ID]]
   // THREADS-NOT: ompt_event_implicit_task_end
   // THREADS: {{^}}[[MASTER_ID]]: ompt_event_barrier_begin
   // THREADS-SAME: parallel_id=[[PARALLEL_ID]], task_id=[[IMPLICIT_TASK_ID]]
   // THREADS-SAME: codeptr_ra=[[RETURN_ADDRESS]]{{[0-f][0-f]}}
+  // THREADS: {{^}}[[MASTER_ID]]: task level 0
+  // THREADS-SAME: parallel_id=[[PARALLEL_ID]], task_id=[[IMPLICIT_TASK_ID]]
+  // THREADS-SAME: exit_frame=[[NULL]], reenter_frame=[[NULL]]
   // THREADS: {{^}}[[MASTER_ID]]: ompt_event_barrier_end
   // parallel_id is 0 because the region ended in the barrier!
   // THREADS-SAME: parallel_id=0, task_id=[[IMPLICIT_TASK_ID]]
   // THREADS-SAME: codeptr_ra=[[RETURN_ADDRESS]]{{[0-f][0-f]}}
   // THREADS: {{^}}[[MASTER_ID]]: ompt_event_implicit_task_end
   // THREADS-SAME: parallel_id=0, task_id=[[IMPLICIT_TASK_ID]]
 
   // THREADS: {{^}}[[THREAD_ID:[0-9]+]]: ompt_event_thread_begin