1 /*
2  * kmp_tasking.cpp -- OpenMP 3.0 tasking support.
3  */
4 
5 //===----------------------------------------------------------------------===//
6 //
7 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
8 // See https://llvm.org/LICENSE.txt for license information.
9 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "kmp.h"
14 #include "kmp_i18n.h"
15 #include "kmp_itt.h"
16 #include "kmp_stats.h"
17 #include "kmp_wait_release.h"
18 #include "kmp_taskdeps.h"
19 
20 #if OMPT_SUPPORT
21 #include "ompt-specific.h"
22 #endif
23 
24 #if ENABLE_LIBOMPTARGET
25 static void (*tgt_target_nowait_query)(void **);
26 
27 void __kmp_init_target_task() {
28   *(void **)(&tgt_target_nowait_query) = KMP_DLSYM("__tgt_target_nowait_query");
29 }
30 #endif
31 
32 /* forward declaration */
33 static void __kmp_enable_tasking(kmp_task_team_t *task_team,
34                                  kmp_info_t *this_thr);
35 static void __kmp_alloc_task_deque(kmp_info_t *thread,
36                                    kmp_thread_data_t *thread_data);
37 static int __kmp_realloc_task_threads_data(kmp_info_t *thread,
38                                            kmp_task_team_t *task_team);
39 static void __kmp_bottom_half_finish_proxy(kmp_int32 gtid, kmp_task_t *ptask);
40 #if OMPX_TASKGRAPH
41 static kmp_tdg_info_t *__kmp_find_tdg(kmp_int32 tdg_id);
42 int __kmp_taskloop_task(int gtid, void *ptask);
43 #endif
44 
45 #ifdef BUILD_TIED_TASK_STACK
46 
47 //  __kmp_trace_task_stack: print the tied tasks from the task stack in order
48 //  from top do bottom
49 //
50 //  gtid: global thread identifier for thread containing stack
51 //  thread_data: thread data for task team thread containing stack
52 //  threshold: value above which the trace statement triggers
53 //  location: string identifying call site of this function (for trace)
54 static void __kmp_trace_task_stack(kmp_int32 gtid,
55                                    kmp_thread_data_t *thread_data,
56                                    int threshold, char *location) {
57   kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
58   kmp_taskdata_t **stack_top = task_stack->ts_top;
59   kmp_int32 entries = task_stack->ts_entries;
60   kmp_taskdata_t *tied_task;
61 
62   KA_TRACE(
63       threshold,
64       ("__kmp_trace_task_stack(start): location = %s, gtid = %d, entries = %d, "
65        "first_block = %p, stack_top = %p \n",
66        location, gtid, entries, task_stack->ts_first_block, stack_top));
67 
68   KMP_DEBUG_ASSERT(stack_top != NULL);
69   KMP_DEBUG_ASSERT(entries > 0);
70 
71   while (entries != 0) {
72     KMP_DEBUG_ASSERT(stack_top != &task_stack->ts_first_block.sb_block[0]);
73     // fix up ts_top if we need to pop from previous block
74     if (entries & TASK_STACK_INDEX_MASK == 0) {
75       kmp_stack_block_t *stack_block = (kmp_stack_block_t *)(stack_top);
76 
77       stack_block = stack_block->sb_prev;
78       stack_top = &stack_block->sb_block[TASK_STACK_BLOCK_SIZE];
79     }
80 
81     // finish bookkeeping
82     stack_top--;
83     entries--;
84 
85     tied_task = *stack_top;
86 
87     KMP_DEBUG_ASSERT(tied_task != NULL);
88     KMP_DEBUG_ASSERT(tied_task->td_flags.tasktype == TASK_TIED);
89 
90     KA_TRACE(threshold,
91              ("__kmp_trace_task_stack(%s):             gtid=%d, entry=%d, "
92               "stack_top=%p, tied_task=%p\n",
93               location, gtid, entries, stack_top, tied_task));
94   }
95   KMP_DEBUG_ASSERT(stack_top == &task_stack->ts_first_block.sb_block[0]);
96 
97   KA_TRACE(threshold,
98            ("__kmp_trace_task_stack(exit): location = %s, gtid = %d\n",
99             location, gtid));
100 }
101 
102 //  __kmp_init_task_stack: initialize the task stack for the first time
103 //  after a thread_data structure is created.
104 //  It should not be necessary to do this again (assuming the stack works).
105 //
106 //  gtid: global thread identifier of calling thread
107 //  thread_data: thread data for task team thread containing stack
108 static void __kmp_init_task_stack(kmp_int32 gtid,
109                                   kmp_thread_data_t *thread_data) {
110   kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
111   kmp_stack_block_t *first_block;
112 
113   // set up the first block of the stack
114   first_block = &task_stack->ts_first_block;
115   task_stack->ts_top = (kmp_taskdata_t **)first_block;
116   memset((void *)first_block, '\0',
117          TASK_STACK_BLOCK_SIZE * sizeof(kmp_taskdata_t *));
118 
119   // initialize the stack to be empty
120   task_stack->ts_entries = TASK_STACK_EMPTY;
121   first_block->sb_next = NULL;
122   first_block->sb_prev = NULL;
123 }
124 
125 //  __kmp_free_task_stack: free the task stack when thread_data is destroyed.
126 //
127 //  gtid: global thread identifier for calling thread
128 //  thread_data: thread info for thread containing stack
129 static void __kmp_free_task_stack(kmp_int32 gtid,
130                                   kmp_thread_data_t *thread_data) {
131   kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
132   kmp_stack_block_t *stack_block = &task_stack->ts_first_block;
133 
134   KMP_DEBUG_ASSERT(task_stack->ts_entries == TASK_STACK_EMPTY);
135   // free from the second block of the stack
136   while (stack_block != NULL) {
137     kmp_stack_block_t *next_block = (stack_block) ? stack_block->sb_next : NULL;
138 
139     stack_block->sb_next = NULL;
140     stack_block->sb_prev = NULL;
141     if (stack_block != &task_stack->ts_first_block) {
142       __kmp_thread_free(thread,
143                         stack_block); // free the block, if not the first
144     }
145     stack_block = next_block;
146   }
147   // initialize the stack to be empty
148   task_stack->ts_entries = 0;
149   task_stack->ts_top = NULL;
150 }
151 
152 //  __kmp_push_task_stack: Push the tied task onto the task stack.
153 //     Grow the stack if necessary by allocating another block.
154 //
155 //  gtid: global thread identifier for calling thread
156 //  thread: thread info for thread containing stack
157 //  tied_task: the task to push on the stack
158 static void __kmp_push_task_stack(kmp_int32 gtid, kmp_info_t *thread,
159                                   kmp_taskdata_t *tied_task) {
160   // GEH - need to consider what to do if tt_threads_data not allocated yet
161   kmp_thread_data_t *thread_data =
162       &thread->th.th_task_team->tt.tt_threads_data[__kmp_tid_from_gtid(gtid)];
163   kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
164 
165   if (tied_task->td_flags.team_serial || tied_task->td_flags.tasking_ser) {
166     return; // Don't push anything on stack if team or team tasks are serialized
167   }
168 
169   KMP_DEBUG_ASSERT(tied_task->td_flags.tasktype == TASK_TIED);
170   KMP_DEBUG_ASSERT(task_stack->ts_top != NULL);
171 
172   KA_TRACE(20,
173            ("__kmp_push_task_stack(enter): GTID: %d; THREAD: %p; TASK: %p\n",
174             gtid, thread, tied_task));
175   // Store entry
176   *(task_stack->ts_top) = tied_task;
177 
178   // Do bookkeeping for next push
179   task_stack->ts_top++;
180   task_stack->ts_entries++;
181 
182   if (task_stack->ts_entries & TASK_STACK_INDEX_MASK == 0) {
183     // Find beginning of this task block
184     kmp_stack_block_t *stack_block =
185         (kmp_stack_block_t *)(task_stack->ts_top - TASK_STACK_BLOCK_SIZE);
186 
187     // Check if we already have a block
188     if (stack_block->sb_next !=
189         NULL) { // reset ts_top to beginning of next block
190       task_stack->ts_top = &stack_block->sb_next->sb_block[0];
191     } else { // Alloc new block and link it up
192       kmp_stack_block_t *new_block = (kmp_stack_block_t *)__kmp_thread_calloc(
193           thread, sizeof(kmp_stack_block_t));
194 
195       task_stack->ts_top = &new_block->sb_block[0];
196       stack_block->sb_next = new_block;
197       new_block->sb_prev = stack_block;
198       new_block->sb_next = NULL;
199 
200       KA_TRACE(
201           30,
202           ("__kmp_push_task_stack(): GTID: %d; TASK: %p; Alloc new block: %p\n",
203            gtid, tied_task, new_block));
204     }
205   }
206   KA_TRACE(20, ("__kmp_push_task_stack(exit): GTID: %d; TASK: %p\n", gtid,
207                 tied_task));
208 }
209 
210 //  __kmp_pop_task_stack: Pop the tied task from the task stack.  Don't return
211 //  the task, just check to make sure it matches the ending task passed in.
212 //
213 //  gtid: global thread identifier for the calling thread
214 //  thread: thread info structure containing stack
215 //  tied_task: the task popped off the stack
216 //  ending_task: the task that is ending (should match popped task)
217 static void __kmp_pop_task_stack(kmp_int32 gtid, kmp_info_t *thread,
218                                  kmp_taskdata_t *ending_task) {
219   // GEH - need to consider what to do if tt_threads_data not allocated yet
220   kmp_thread_data_t *thread_data =
221       &thread->th.th_task_team->tt_threads_data[__kmp_tid_from_gtid(gtid)];
222   kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
223   kmp_taskdata_t *tied_task;
224 
225   if (ending_task->td_flags.team_serial || ending_task->td_flags.tasking_ser) {
226     // Don't pop anything from stack if team or team tasks are serialized
227     return;
228   }
229 
230   KMP_DEBUG_ASSERT(task_stack->ts_top != NULL);
231   KMP_DEBUG_ASSERT(task_stack->ts_entries > 0);
232 
233   KA_TRACE(20, ("__kmp_pop_task_stack(enter): GTID: %d; THREAD: %p\n", gtid,
234                 thread));
235 
236   // fix up ts_top if we need to pop from previous block
237   if (task_stack->ts_entries & TASK_STACK_INDEX_MASK == 0) {
238     kmp_stack_block_t *stack_block = (kmp_stack_block_t *)(task_stack->ts_top);
239 
240     stack_block = stack_block->sb_prev;
241     task_stack->ts_top = &stack_block->sb_block[TASK_STACK_BLOCK_SIZE];
242   }
243 
244   // finish bookkeeping
245   task_stack->ts_top--;
246   task_stack->ts_entries--;
247 
248   tied_task = *(task_stack->ts_top);
249 
250   KMP_DEBUG_ASSERT(tied_task != NULL);
251   KMP_DEBUG_ASSERT(tied_task->td_flags.tasktype == TASK_TIED);
252   KMP_DEBUG_ASSERT(tied_task == ending_task); // If we built the stack correctly
253 
254   KA_TRACE(20, ("__kmp_pop_task_stack(exit): GTID: %d; TASK: %p\n", gtid,
255                 tied_task));
256   return;
257 }
258 #endif /* BUILD_TIED_TASK_STACK */
259 
260 // returns 1 if new task is allowed to execute, 0 otherwise
261 // checks Task Scheduling constraint (if requested) and
262 // mutexinoutset dependencies if any
263 static bool __kmp_task_is_allowed(int gtid, const kmp_int32 is_constrained,
264                                   const kmp_taskdata_t *tasknew,
265                                   const kmp_taskdata_t *taskcurr) {
266   if (is_constrained && (tasknew->td_flags.tiedness == TASK_TIED)) {
267     // Check if the candidate obeys the Task Scheduling Constraints (TSC)
268     // only descendant of all deferred tied tasks can be scheduled, checking
269     // the last one is enough, as it in turn is the descendant of all others
270     kmp_taskdata_t *current = taskcurr->td_last_tied;
271     KMP_DEBUG_ASSERT(current != NULL);
272     // check if the task is not suspended on barrier
273     if (current->td_flags.tasktype == TASK_EXPLICIT ||
274         current->td_taskwait_thread > 0) { // <= 0 on barrier
275       kmp_int32 level = current->td_level;
276       kmp_taskdata_t *parent = tasknew->td_parent;
277       while (parent != current && parent->td_level > level) {
278         // check generation up to the level of the current task
279         parent = parent->td_parent;
280         KMP_DEBUG_ASSERT(parent != NULL);
281       }
282       if (parent != current)
283         return false;
284     }
285   }
286   // Check mutexinoutset dependencies, acquire locks
287   kmp_depnode_t *node = tasknew->td_depnode;
288 #if OMPX_TASKGRAPH
289   if (!tasknew->is_taskgraph && UNLIKELY(node && (node->dn.mtx_num_locks > 0))) {
290 #else
291   if (UNLIKELY(node && (node->dn.mtx_num_locks > 0))) {
292 #endif
293     for (int i = 0; i < node->dn.mtx_num_locks; ++i) {
294       KMP_DEBUG_ASSERT(node->dn.mtx_locks[i] != NULL);
295       if (__kmp_test_lock(node->dn.mtx_locks[i], gtid))
296         continue;
297       // could not get the lock, release previous locks
298       for (int j = i - 1; j >= 0; --j)
299         __kmp_release_lock(node->dn.mtx_locks[j], gtid);
300       return false;
301     }
302     // negative num_locks means all locks acquired successfully
303     node->dn.mtx_num_locks = -node->dn.mtx_num_locks;
304   }
305   return true;
306 }
307 
308 // __kmp_realloc_task_deque:
309 // Re-allocates a task deque for a particular thread, copies the content from
310 // the old deque and adjusts the necessary data structures relating to the
311 // deque. This operation must be done with the deque_lock being held
312 static void __kmp_realloc_task_deque(kmp_info_t *thread,
313                                      kmp_thread_data_t *thread_data) {
314   kmp_int32 size = TASK_DEQUE_SIZE(thread_data->td);
315   KMP_DEBUG_ASSERT(TCR_4(thread_data->td.td_deque_ntasks) == size);
316   kmp_int32 new_size = 2 * size;
317 
318   KE_TRACE(10, ("__kmp_realloc_task_deque: T#%d reallocating deque[from %d to "
319                 "%d] for thread_data %p\n",
320                 __kmp_gtid_from_thread(thread), size, new_size, thread_data));
321 
322   kmp_taskdata_t **new_deque =
323       (kmp_taskdata_t **)__kmp_allocate(new_size * sizeof(kmp_taskdata_t *));
324 
325   int i, j;
326   for (i = thread_data->td.td_deque_head, j = 0; j < size;
327        i = (i + 1) & TASK_DEQUE_MASK(thread_data->td), j++)
328     new_deque[j] = thread_data->td.td_deque[i];
329 
330   __kmp_free(thread_data->td.td_deque);
331 
332   thread_data->td.td_deque_head = 0;
333   thread_data->td.td_deque_tail = size;
334   thread_data->td.td_deque = new_deque;
335   thread_data->td.td_deque_size = new_size;
336 }
337 
338 static kmp_task_pri_t *__kmp_alloc_task_pri_list() {
339   kmp_task_pri_t *l = (kmp_task_pri_t *)__kmp_allocate(sizeof(kmp_task_pri_t));
340   kmp_thread_data_t *thread_data = &l->td;
341   __kmp_init_bootstrap_lock(&thread_data->td.td_deque_lock);
342   thread_data->td.td_deque_last_stolen = -1;
343   KE_TRACE(20, ("__kmp_alloc_task_pri_list: T#%d allocating deque[%d] "
344                 "for thread_data %p\n",
345                 __kmp_get_gtid(), INITIAL_TASK_DEQUE_SIZE, thread_data));
346   thread_data->td.td_deque = (kmp_taskdata_t **)__kmp_allocate(
347       INITIAL_TASK_DEQUE_SIZE * sizeof(kmp_taskdata_t *));
348   thread_data->td.td_deque_size = INITIAL_TASK_DEQUE_SIZE;
349   return l;
350 }
351 
352 // The function finds the deque of priority tasks with given priority, or
353 // allocates a new deque and put it into sorted (high -> low) list of deques.
354 // Deques of non-default priority tasks are shared between all threads in team,
355 // as opposed to per-thread deques of tasks with default priority.
356 // The function is called under the lock task_team->tt.tt_task_pri_lock.
357 static kmp_thread_data_t *
358 __kmp_get_priority_deque_data(kmp_task_team_t *task_team, kmp_int32 pri) {
359   kmp_thread_data_t *thread_data;
360   kmp_task_pri_t *lst = task_team->tt.tt_task_pri_list;
361   if (lst->priority == pri) {
362     // Found queue of tasks with given priority.
363     thread_data = &lst->td;
364   } else if (lst->priority < pri) {
365     // All current priority queues contain tasks with lower priority.
366     // Allocate new one for given priority tasks.
367     kmp_task_pri_t *list = __kmp_alloc_task_pri_list();
368     thread_data = &list->td;
369     list->priority = pri;
370     list->next = lst;
371     task_team->tt.tt_task_pri_list = list;
372   } else { // task_team->tt.tt_task_pri_list->priority > pri
373     kmp_task_pri_t *next_queue = lst->next;
374     while (next_queue && next_queue->priority > pri) {
375       lst = next_queue;
376       next_queue = lst->next;
377     }
378     // lst->priority > pri && (next == NULL || pri >= next->priority)
379     if (next_queue == NULL) {
380       // No queue with pri priority, need to allocate new one.
381       kmp_task_pri_t *list = __kmp_alloc_task_pri_list();
382       thread_data = &list->td;
383       list->priority = pri;
384       list->next = NULL;
385       lst->next = list;
386     } else if (next_queue->priority == pri) {
387       // Found queue of tasks with given priority.
388       thread_data = &next_queue->td;
389     } else { // lst->priority > pri > next->priority
390       // insert newly allocated between existed queues
391       kmp_task_pri_t *list = __kmp_alloc_task_pri_list();
392       thread_data = &list->td;
393       list->priority = pri;
394       list->next = next_queue;
395       lst->next = list;
396     }
397   }
398   return thread_data;
399 }
400 
401 //  __kmp_push_priority_task: Add a task to the team's priority task deque
402 static kmp_int32 __kmp_push_priority_task(kmp_int32 gtid, kmp_info_t *thread,
403                                           kmp_taskdata_t *taskdata,
404                                           kmp_task_team_t *task_team,
405                                           kmp_int32 pri) {
406   kmp_thread_data_t *thread_data = NULL;
407   KA_TRACE(20,
408            ("__kmp_push_priority_task: T#%d trying to push task %p, pri %d.\n",
409             gtid, taskdata, pri));
410 
411   // Find task queue specific to priority value
412   kmp_task_pri_t *lst = task_team->tt.tt_task_pri_list;
413   if (UNLIKELY(lst == NULL)) {
414     __kmp_acquire_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
415     if (task_team->tt.tt_task_pri_list == NULL) {
416       // List of queues is still empty, allocate one.
417       kmp_task_pri_t *list = __kmp_alloc_task_pri_list();
418       thread_data = &list->td;
419       list->priority = pri;
420       list->next = NULL;
421       task_team->tt.tt_task_pri_list = list;
422     } else {
423       // Other thread initialized a queue. Check if it fits and get thread_data.
424       thread_data = __kmp_get_priority_deque_data(task_team, pri);
425     }
426     __kmp_release_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
427   } else {
428     if (lst->priority == pri) {
429       // Found queue of tasks with given priority.
430       thread_data = &lst->td;
431     } else {
432       __kmp_acquire_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
433       thread_data = __kmp_get_priority_deque_data(task_team, pri);
434       __kmp_release_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
435     }
436   }
437   KMP_DEBUG_ASSERT(thread_data);
438 
439   __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
440   // Check if deque is full
441   if (TCR_4(thread_data->td.td_deque_ntasks) >=
442       TASK_DEQUE_SIZE(thread_data->td)) {
443     if (__kmp_enable_task_throttling &&
444         __kmp_task_is_allowed(gtid, __kmp_task_stealing_constraint, taskdata,
445                               thread->th.th_current_task)) {
446       __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
447       KA_TRACE(20, ("__kmp_push_priority_task: T#%d deque is full; returning "
448                     "TASK_NOT_PUSHED for task %p\n",
449                     gtid, taskdata));
450       return TASK_NOT_PUSHED;
451     } else {
452       // expand deque to push the task which is not allowed to execute
453       __kmp_realloc_task_deque(thread, thread_data);
454     }
455   }
456   KMP_DEBUG_ASSERT(TCR_4(thread_data->td.td_deque_ntasks) <
457                    TASK_DEQUE_SIZE(thread_data->td));
458   // Push taskdata.
459   thread_data->td.td_deque[thread_data->td.td_deque_tail] = taskdata;
460   // Wrap index.
461   thread_data->td.td_deque_tail =
462       (thread_data->td.td_deque_tail + 1) & TASK_DEQUE_MASK(thread_data->td);
463   TCW_4(thread_data->td.td_deque_ntasks,
464         TCR_4(thread_data->td.td_deque_ntasks) + 1); // Adjust task count
465   KMP_FSYNC_RELEASING(thread->th.th_current_task); // releasing self
466   KMP_FSYNC_RELEASING(taskdata); // releasing child
467   KA_TRACE(20, ("__kmp_push_priority_task: T#%d returning "
468                 "TASK_SUCCESSFULLY_PUSHED: task=%p ntasks=%d head=%u tail=%u\n",
469                 gtid, taskdata, thread_data->td.td_deque_ntasks,
470                 thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
471   __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
472   task_team->tt.tt_num_task_pri++; // atomic inc
473   return TASK_SUCCESSFULLY_PUSHED;
474 }
475 
476 //  __kmp_push_task: Add a task to the thread's deque
477 static kmp_int32 __kmp_push_task(kmp_int32 gtid, kmp_task_t *task) {
478   kmp_info_t *thread = __kmp_threads[gtid];
479   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
480 
481   // If we encounter a hidden helper task, and the current thread is not a
482   // hidden helper thread, we have to give the task to any hidden helper thread
483   // starting from its shadow one.
484   if (UNLIKELY(taskdata->td_flags.hidden_helper &&
485                !KMP_HIDDEN_HELPER_THREAD(gtid))) {
486     kmp_int32 shadow_gtid = KMP_GTID_TO_SHADOW_GTID(gtid);
487     __kmpc_give_task(task, __kmp_tid_from_gtid(shadow_gtid));
488     // Signal the hidden helper threads.
489     __kmp_hidden_helper_worker_thread_signal();
490     return TASK_SUCCESSFULLY_PUSHED;
491   }
492 
493   kmp_task_team_t *task_team = thread->th.th_task_team;
494   kmp_int32 tid = __kmp_tid_from_gtid(gtid);
495   kmp_thread_data_t *thread_data;
496 
497   KA_TRACE(20,
498            ("__kmp_push_task: T#%d trying to push task %p.\n", gtid, taskdata));
499 
500   if (UNLIKELY(taskdata->td_flags.tiedness == TASK_UNTIED)) {
501     // untied task needs to increment counter so that the task structure is not
502     // freed prematurely
503     kmp_int32 counter = 1 + KMP_ATOMIC_INC(&taskdata->td_untied_count);
504     KMP_DEBUG_USE_VAR(counter);
505     KA_TRACE(
506         20,
507         ("__kmp_push_task: T#%d untied_count (%d) incremented for task %p\n",
508          gtid, counter, taskdata));
509   }
510 
511   // The first check avoids building task_team thread data if serialized
512   if (UNLIKELY(taskdata->td_flags.task_serial)) {
513     KA_TRACE(20, ("__kmp_push_task: T#%d team serialized; returning "
514                   "TASK_NOT_PUSHED for task %p\n",
515                   gtid, taskdata));
516     return TASK_NOT_PUSHED;
517   }
518 
519   // Now that serialized tasks have returned, we can assume that we are not in
520   // immediate exec mode
521   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
522   if (UNLIKELY(!KMP_TASKING_ENABLED(task_team))) {
523     __kmp_enable_tasking(task_team, thread);
524   }
525   KMP_DEBUG_ASSERT(TCR_4(task_team->tt.tt_found_tasks) == TRUE);
526   KMP_DEBUG_ASSERT(TCR_PTR(task_team->tt.tt_threads_data) != NULL);
527 
528   if (taskdata->td_flags.priority_specified && task->data2.priority > 0 &&
529       __kmp_max_task_priority > 0) {
530     int pri = KMP_MIN(task->data2.priority, __kmp_max_task_priority);
531     return __kmp_push_priority_task(gtid, thread, taskdata, task_team, pri);
532   }
533 
534   // Find tasking deque specific to encountering thread
535   thread_data = &task_team->tt.tt_threads_data[tid];
536 
537   // No lock needed since only owner can allocate. If the task is hidden_helper,
538   // we don't need it either because we have initialized the dequeue for hidden
539   // helper thread data.
540   if (UNLIKELY(thread_data->td.td_deque == NULL)) {
541     __kmp_alloc_task_deque(thread, thread_data);
542   }
543 
544   int locked = 0;
545   // Check if deque is full
546   if (TCR_4(thread_data->td.td_deque_ntasks) >=
547       TASK_DEQUE_SIZE(thread_data->td)) {
548     if (__kmp_enable_task_throttling &&
549         __kmp_task_is_allowed(gtid, __kmp_task_stealing_constraint, taskdata,
550                               thread->th.th_current_task)) {
551       KA_TRACE(20, ("__kmp_push_task: T#%d deque is full; returning "
552                     "TASK_NOT_PUSHED for task %p\n",
553                     gtid, taskdata));
554       return TASK_NOT_PUSHED;
555     } else {
556       __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
557       locked = 1;
558       if (TCR_4(thread_data->td.td_deque_ntasks) >=
559           TASK_DEQUE_SIZE(thread_data->td)) {
560         // expand deque to push the task which is not allowed to execute
561         __kmp_realloc_task_deque(thread, thread_data);
562       }
563     }
564   }
565   // Lock the deque for the task push operation
566   if (!locked) {
567     __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
568     // Need to recheck as we can get a proxy task from thread outside of OpenMP
569     if (TCR_4(thread_data->td.td_deque_ntasks) >=
570         TASK_DEQUE_SIZE(thread_data->td)) {
571       if (__kmp_enable_task_throttling &&
572           __kmp_task_is_allowed(gtid, __kmp_task_stealing_constraint, taskdata,
573                                 thread->th.th_current_task)) {
574         __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
575         KA_TRACE(20, ("__kmp_push_task: T#%d deque is full on 2nd check; "
576                       "returning TASK_NOT_PUSHED for task %p\n",
577                       gtid, taskdata));
578         return TASK_NOT_PUSHED;
579       } else {
580         // expand deque to push the task which is not allowed to execute
581         __kmp_realloc_task_deque(thread, thread_data);
582       }
583     }
584   }
585   // Must have room since no thread can add tasks but calling thread
586   KMP_DEBUG_ASSERT(TCR_4(thread_data->td.td_deque_ntasks) <
587                    TASK_DEQUE_SIZE(thread_data->td));
588 
589   thread_data->td.td_deque[thread_data->td.td_deque_tail] =
590       taskdata; // Push taskdata
591   // Wrap index.
592   thread_data->td.td_deque_tail =
593       (thread_data->td.td_deque_tail + 1) & TASK_DEQUE_MASK(thread_data->td);
594   TCW_4(thread_data->td.td_deque_ntasks,
595         TCR_4(thread_data->td.td_deque_ntasks) + 1); // Adjust task count
596   KMP_FSYNC_RELEASING(thread->th.th_current_task); // releasing self
597   KMP_FSYNC_RELEASING(taskdata); // releasing child
598   KA_TRACE(20, ("__kmp_push_task: T#%d returning TASK_SUCCESSFULLY_PUSHED: "
599                 "task=%p ntasks=%d head=%u tail=%u\n",
600                 gtid, taskdata, thread_data->td.td_deque_ntasks,
601                 thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
602 
603   __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
604 
605   return TASK_SUCCESSFULLY_PUSHED;
606 }
607 
608 // __kmp_pop_current_task_from_thread: set up current task from called thread
609 // when team ends
610 //
611 // this_thr: thread structure to set current_task in.
612 void __kmp_pop_current_task_from_thread(kmp_info_t *this_thr) {
613   KF_TRACE(10, ("__kmp_pop_current_task_from_thread(enter): T#%d "
614                 "this_thread=%p, curtask=%p, "
615                 "curtask_parent=%p\n",
616                 0, this_thr, this_thr->th.th_current_task,
617                 this_thr->th.th_current_task->td_parent));
618 
619   this_thr->th.th_current_task = this_thr->th.th_current_task->td_parent;
620 
621   KF_TRACE(10, ("__kmp_pop_current_task_from_thread(exit): T#%d "
622                 "this_thread=%p, curtask=%p, "
623                 "curtask_parent=%p\n",
624                 0, this_thr, this_thr->th.th_current_task,
625                 this_thr->th.th_current_task->td_parent));
626 }
627 
628 // __kmp_push_current_task_to_thread: set up current task in called thread for a
629 // new team
630 //
631 // this_thr: thread structure to set up
632 // team: team for implicit task data
633 // tid: thread within team to set up
634 void __kmp_push_current_task_to_thread(kmp_info_t *this_thr, kmp_team_t *team,
635                                        int tid) {
636   // current task of the thread is a parent of the new just created implicit
637   // tasks of new team
638   KF_TRACE(10, ("__kmp_push_current_task_to_thread(enter): T#%d this_thread=%p "
639                 "curtask=%p "
640                 "parent_task=%p\n",
641                 tid, this_thr, this_thr->th.th_current_task,
642                 team->t.t_implicit_task_taskdata[tid].td_parent));
643 
644   KMP_DEBUG_ASSERT(this_thr != NULL);
645 
646   if (tid == 0) {
647     if (this_thr->th.th_current_task != &team->t.t_implicit_task_taskdata[0]) {
648       team->t.t_implicit_task_taskdata[0].td_parent =
649           this_thr->th.th_current_task;
650       this_thr->th.th_current_task = &team->t.t_implicit_task_taskdata[0];
651     }
652   } else {
653     team->t.t_implicit_task_taskdata[tid].td_parent =
654         team->t.t_implicit_task_taskdata[0].td_parent;
655     this_thr->th.th_current_task = &team->t.t_implicit_task_taskdata[tid];
656   }
657 
658   KF_TRACE(10, ("__kmp_push_current_task_to_thread(exit): T#%d this_thread=%p "
659                 "curtask=%p "
660                 "parent_task=%p\n",
661                 tid, this_thr, this_thr->th.th_current_task,
662                 team->t.t_implicit_task_taskdata[tid].td_parent));
663 }
664 
665 // __kmp_task_start: bookkeeping for a task starting execution
666 //
667 // GTID: global thread id of calling thread
668 // task: task starting execution
669 // current_task: task suspending
670 static void __kmp_task_start(kmp_int32 gtid, kmp_task_t *task,
671                              kmp_taskdata_t *current_task) {
672   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
673   kmp_info_t *thread = __kmp_threads[gtid];
674 
675   KA_TRACE(10,
676            ("__kmp_task_start(enter): T#%d starting task %p: current_task=%p\n",
677             gtid, taskdata, current_task));
678 
679   KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
680 
681   // mark currently executing task as suspended
682   // TODO: GEH - make sure root team implicit task is initialized properly.
683   // KMP_DEBUG_ASSERT( current_task -> td_flags.executing == 1 );
684   current_task->td_flags.executing = 0;
685 
686 // Add task to stack if tied
687 #ifdef BUILD_TIED_TASK_STACK
688   if (taskdata->td_flags.tiedness == TASK_TIED) {
689     __kmp_push_task_stack(gtid, thread, taskdata);
690   }
691 #endif /* BUILD_TIED_TASK_STACK */
692 
693   // mark starting task as executing and as current task
694   thread->th.th_current_task = taskdata;
695 
696   KMP_DEBUG_ASSERT(taskdata->td_flags.started == 0 ||
697                    taskdata->td_flags.tiedness == TASK_UNTIED);
698   KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 0 ||
699                    taskdata->td_flags.tiedness == TASK_UNTIED);
700   taskdata->td_flags.started = 1;
701   taskdata->td_flags.executing = 1;
702   KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 0);
703   KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
704 
705   // GEH TODO: shouldn't we pass some sort of location identifier here?
706   // APT: yes, we will pass location here.
707   // need to store current thread state (in a thread or taskdata structure)
708   // before setting work_state, otherwise wrong state is set after end of task
709 
710   KA_TRACE(10, ("__kmp_task_start(exit): T#%d task=%p\n", gtid, taskdata));
711 
712   return;
713 }
714 
715 #if OMPT_SUPPORT
716 //------------------------------------------------------------------------------
717 // __ompt_task_init:
718 //   Initialize OMPT fields maintained by a task. This will only be called after
719 //   ompt_start_tool, so we already know whether ompt is enabled or not.
720 
721 static inline void __ompt_task_init(kmp_taskdata_t *task, int tid) {
722   // The calls to __ompt_task_init already have the ompt_enabled condition.
723   task->ompt_task_info.task_data.value = 0;
724   task->ompt_task_info.frame.exit_frame = ompt_data_none;
725   task->ompt_task_info.frame.enter_frame = ompt_data_none;
726   task->ompt_task_info.frame.exit_frame_flags =
727       ompt_frame_runtime | ompt_frame_framepointer;
728   task->ompt_task_info.frame.enter_frame_flags =
729       ompt_frame_runtime | ompt_frame_framepointer;
730   task->ompt_task_info.dispatch_chunk.start = 0;
731   task->ompt_task_info.dispatch_chunk.iterations = 0;
732 }
733 
734 // __ompt_task_start:
735 //   Build and trigger task-begin event
736 static inline void __ompt_task_start(kmp_task_t *task,
737                                      kmp_taskdata_t *current_task,
738                                      kmp_int32 gtid) {
739   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
740   ompt_task_status_t status = ompt_task_switch;
741   if (__kmp_threads[gtid]->th.ompt_thread_info.ompt_task_yielded) {
742     status = ompt_task_yield;
743     __kmp_threads[gtid]->th.ompt_thread_info.ompt_task_yielded = 0;
744   }
745   /* let OMPT know that we're about to run this task */
746   if (ompt_enabled.ompt_callback_task_schedule) {
747     ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
748         &(current_task->ompt_task_info.task_data), status,
749         &(taskdata->ompt_task_info.task_data));
750   }
751   taskdata->ompt_task_info.scheduling_parent = current_task;
752 }
753 
754 // __ompt_task_finish:
755 //   Build and trigger final task-schedule event
756 static inline void __ompt_task_finish(kmp_task_t *task,
757                                       kmp_taskdata_t *resumed_task,
758                                       ompt_task_status_t status) {
759   if (ompt_enabled.ompt_callback_task_schedule) {
760     kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
761     if (__kmp_omp_cancellation && taskdata->td_taskgroup &&
762         taskdata->td_taskgroup->cancel_request == cancel_taskgroup) {
763       status = ompt_task_cancel;
764     }
765 
766     /* let OMPT know that we're returning to the callee task */
767     ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
768         &(taskdata->ompt_task_info.task_data), status,
769         (resumed_task ? &(resumed_task->ompt_task_info.task_data) : NULL));
770   }
771 }
772 #endif
773 
774 template <bool ompt>
775 static void __kmpc_omp_task_begin_if0_template(ident_t *loc_ref, kmp_int32 gtid,
776                                                kmp_task_t *task,
777                                                void *frame_address,
778                                                void *return_address) {
779   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
780   kmp_taskdata_t *current_task = __kmp_threads[gtid]->th.th_current_task;
781 
782   KA_TRACE(10, ("__kmpc_omp_task_begin_if0(enter): T#%d loc=%p task=%p "
783                 "current_task=%p\n",
784                 gtid, loc_ref, taskdata, current_task));
785 
786   if (UNLIKELY(taskdata->td_flags.tiedness == TASK_UNTIED)) {
787     // untied task needs to increment counter so that the task structure is not
788     // freed prematurely
789     kmp_int32 counter = 1 + KMP_ATOMIC_INC(&taskdata->td_untied_count);
790     KMP_DEBUG_USE_VAR(counter);
791     KA_TRACE(20, ("__kmpc_omp_task_begin_if0: T#%d untied_count (%d) "
792                   "incremented for task %p\n",
793                   gtid, counter, taskdata));
794   }
795 
796   taskdata->td_flags.task_serial =
797       1; // Execute this task immediately, not deferred.
798   __kmp_task_start(gtid, task, current_task);
799 
800 #if OMPT_SUPPORT
801   if (ompt) {
802     if (current_task->ompt_task_info.frame.enter_frame.ptr == NULL) {
803       current_task->ompt_task_info.frame.enter_frame.ptr =
804           taskdata->ompt_task_info.frame.exit_frame.ptr = frame_address;
805       current_task->ompt_task_info.frame.enter_frame_flags =
806           taskdata->ompt_task_info.frame.exit_frame_flags =
807               ompt_frame_application | ompt_frame_framepointer;
808     }
809     if (ompt_enabled.ompt_callback_task_create) {
810       ompt_task_info_t *parent_info = &(current_task->ompt_task_info);
811       ompt_callbacks.ompt_callback(ompt_callback_task_create)(
812           &(parent_info->task_data), &(parent_info->frame),
813           &(taskdata->ompt_task_info.task_data),
814           ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(taskdata), 0,
815           return_address);
816     }
817     __ompt_task_start(task, current_task, gtid);
818   }
819 #endif // OMPT_SUPPORT
820 
821   KA_TRACE(10, ("__kmpc_omp_task_begin_if0(exit): T#%d loc=%p task=%p,\n", gtid,
822                 loc_ref, taskdata));
823 }
824 
825 #if OMPT_SUPPORT
826 OMPT_NOINLINE
827 static void __kmpc_omp_task_begin_if0_ompt(ident_t *loc_ref, kmp_int32 gtid,
828                                            kmp_task_t *task,
829                                            void *frame_address,
830                                            void *return_address) {
831   __kmpc_omp_task_begin_if0_template<true>(loc_ref, gtid, task, frame_address,
832                                            return_address);
833 }
834 #endif // OMPT_SUPPORT
835 
836 // __kmpc_omp_task_begin_if0: report that a given serialized task has started
837 // execution
838 //
839 // loc_ref: source location information; points to beginning of task block.
840 // gtid: global thread number.
841 // task: task thunk for the started task.
842 void __kmpc_omp_task_begin_if0(ident_t *loc_ref, kmp_int32 gtid,
843                                kmp_task_t *task) {
844 #if OMPT_SUPPORT
845   if (UNLIKELY(ompt_enabled.enabled)) {
846     OMPT_STORE_RETURN_ADDRESS(gtid);
847     __kmpc_omp_task_begin_if0_ompt(loc_ref, gtid, task,
848                                    OMPT_GET_FRAME_ADDRESS(1),
849                                    OMPT_LOAD_RETURN_ADDRESS(gtid));
850     return;
851   }
852 #endif
853   __kmpc_omp_task_begin_if0_template<false>(loc_ref, gtid, task, NULL, NULL);
854 }
855 
856 #ifdef TASK_UNUSED
857 // __kmpc_omp_task_begin: report that a given task has started execution
858 // NEVER GENERATED BY COMPILER, DEPRECATED!!!
859 void __kmpc_omp_task_begin(ident_t *loc_ref, kmp_int32 gtid, kmp_task_t *task) {
860   kmp_taskdata_t *current_task = __kmp_threads[gtid]->th.th_current_task;
861 
862   KA_TRACE(
863       10,
864       ("__kmpc_omp_task_begin(enter): T#%d loc=%p task=%p current_task=%p\n",
865        gtid, loc_ref, KMP_TASK_TO_TASKDATA(task), current_task));
866 
867   __kmp_task_start(gtid, task, current_task);
868 
869   KA_TRACE(10, ("__kmpc_omp_task_begin(exit): T#%d loc=%p task=%p,\n", gtid,
870                 loc_ref, KMP_TASK_TO_TASKDATA(task)));
871   return;
872 }
873 #endif // TASK_UNUSED
874 
875 // __kmp_free_task: free the current task space and the space for shareds
876 //
877 // gtid: Global thread ID of calling thread
878 // taskdata: task to free
879 // thread: thread data structure of caller
880 static void __kmp_free_task(kmp_int32 gtid, kmp_taskdata_t *taskdata,
881                             kmp_info_t *thread) {
882   KA_TRACE(30, ("__kmp_free_task: T#%d freeing data from task %p\n", gtid,
883                 taskdata));
884 
885   // Check to make sure all flags and counters have the correct values
886   KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
887   KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 0);
888   KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 1);
889   KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
890   KMP_DEBUG_ASSERT(taskdata->td_allocated_child_tasks == 0 ||
891                    taskdata->td_flags.task_serial == 1);
892   KMP_DEBUG_ASSERT(taskdata->td_incomplete_child_tasks == 0);
893   kmp_task_t *task = KMP_TASKDATA_TO_TASK(taskdata);
894   // Clear data to not be re-used later by mistake.
895   task->data1.destructors = NULL;
896   task->data2.priority = 0;
897 
898   taskdata->td_flags.freed = 1;
899 #if OMPX_TASKGRAPH
900   // do not free tasks in taskgraph
901   if (!taskdata->is_taskgraph) {
902 #endif
903 // deallocate the taskdata and shared variable blocks associated with this task
904 #if USE_FAST_MEMORY
905   __kmp_fast_free(thread, taskdata);
906 #else /* ! USE_FAST_MEMORY */
907   __kmp_thread_free(thread, taskdata);
908 #endif
909 #if OMPX_TASKGRAPH
910   } else {
911     taskdata->td_flags.complete = 0;
912     taskdata->td_flags.started = 0;
913     taskdata->td_flags.freed = 0;
914     taskdata->td_flags.executing = 0;
915     taskdata->td_flags.task_serial =
916         (taskdata->td_parent->td_flags.final ||
917           taskdata->td_flags.team_serial || taskdata->td_flags.tasking_ser);
918 
919     // taskdata->td_allow_completion_event.pending_events_count = 1;
920     KMP_ATOMIC_ST_RLX(&taskdata->td_untied_count, 0);
921     KMP_ATOMIC_ST_RLX(&taskdata->td_incomplete_child_tasks, 0);
922     // start at one because counts current task and children
923     KMP_ATOMIC_ST_RLX(&taskdata->td_allocated_child_tasks, 1);
924   }
925 #endif
926 
927   KA_TRACE(20, ("__kmp_free_task: T#%d freed task %p\n", gtid, taskdata));
928 }
929 
930 // __kmp_free_task_and_ancestors: free the current task and ancestors without
931 // children
932 //
933 // gtid: Global thread ID of calling thread
934 // taskdata: task to free
935 // thread: thread data structure of caller
936 static void __kmp_free_task_and_ancestors(kmp_int32 gtid,
937                                           kmp_taskdata_t *taskdata,
938                                           kmp_info_t *thread) {
939   // Proxy tasks must always be allowed to free their parents
940   // because they can be run in background even in serial mode.
941   kmp_int32 team_serial =
942       (taskdata->td_flags.team_serial || taskdata->td_flags.tasking_ser) &&
943       !taskdata->td_flags.proxy;
944   KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
945 
946   kmp_int32 children = KMP_ATOMIC_DEC(&taskdata->td_allocated_child_tasks) - 1;
947   KMP_DEBUG_ASSERT(children >= 0);
948 
949   // Now, go up the ancestor tree to see if any ancestors can now be freed.
950   while (children == 0) {
951     kmp_taskdata_t *parent_taskdata = taskdata->td_parent;
952 
953     KA_TRACE(20, ("__kmp_free_task_and_ancestors(enter): T#%d task %p complete "
954                   "and freeing itself\n",
955                   gtid, taskdata));
956 
957     // --- Deallocate my ancestor task ---
958     __kmp_free_task(gtid, taskdata, thread);
959 
960     taskdata = parent_taskdata;
961 
962     if (team_serial)
963       return;
964     // Stop checking ancestors at implicit task instead of walking up ancestor
965     // tree to avoid premature deallocation of ancestors.
966     if (taskdata->td_flags.tasktype == TASK_IMPLICIT) {
967       if (taskdata->td_dephash) { // do we need to cleanup dephash?
968         int children = KMP_ATOMIC_LD_ACQ(&taskdata->td_incomplete_child_tasks);
969         kmp_tasking_flags_t flags_old = taskdata->td_flags;
970         if (children == 0 && flags_old.complete == 1) {
971           kmp_tasking_flags_t flags_new = flags_old;
972           flags_new.complete = 0;
973           if (KMP_COMPARE_AND_STORE_ACQ32(
974                   RCAST(kmp_int32 *, &taskdata->td_flags),
975                   *RCAST(kmp_int32 *, &flags_old),
976                   *RCAST(kmp_int32 *, &flags_new))) {
977             KA_TRACE(100, ("__kmp_free_task_and_ancestors: T#%d cleans "
978                            "dephash of implicit task %p\n",
979                            gtid, taskdata));
980             // cleanup dephash of finished implicit task
981             __kmp_dephash_free_entries(thread, taskdata->td_dephash);
982           }
983         }
984       }
985       return;
986     }
987     // Predecrement simulated by "- 1" calculation
988     children = KMP_ATOMIC_DEC(&taskdata->td_allocated_child_tasks) - 1;
989     KMP_DEBUG_ASSERT(children >= 0);
990   }
991 
992   KA_TRACE(
993       20, ("__kmp_free_task_and_ancestors(exit): T#%d task %p has %d children; "
994            "not freeing it yet\n",
995            gtid, taskdata, children));
996 }
997 
998 // Only need to keep track of child task counts if any of the following:
999 // 1. team parallel and tasking not serialized;
1000 // 2. it is a proxy or detachable or hidden helper task
1001 // 3. the children counter of its parent task is greater than 0.
1002 // The reason for the 3rd one is for serialized team that found detached task,
1003 // hidden helper task, T. In this case, the execution of T is still deferred,
1004 // and it is also possible that a regular task depends on T. In this case, if we
1005 // don't track the children, task synchronization will be broken.
1006 static bool __kmp_track_children_task(kmp_taskdata_t *taskdata) {
1007   kmp_tasking_flags_t flags = taskdata->td_flags;
1008   bool ret = !(flags.team_serial || flags.tasking_ser);
1009   ret = ret || flags.proxy == TASK_PROXY ||
1010         flags.detachable == TASK_DETACHABLE || flags.hidden_helper;
1011   ret = ret ||
1012         KMP_ATOMIC_LD_ACQ(&taskdata->td_parent->td_incomplete_child_tasks) > 0;
1013 #if OMPX_TASKGRAPH
1014   if (taskdata->td_taskgroup && taskdata->is_taskgraph)
1015     ret = ret || KMP_ATOMIC_LD_ACQ(&taskdata->td_taskgroup->count) > 0;
1016 #endif
1017   return ret;
1018 }
1019 
1020 // __kmp_task_finish: bookkeeping to do when a task finishes execution
1021 //
1022 // gtid: global thread ID for calling thread
1023 // task: task to be finished
1024 // resumed_task: task to be resumed.  (may be NULL if task is serialized)
1025 //
1026 // template<ompt>: effectively ompt_enabled.enabled!=0
1027 // the version with ompt=false is inlined, allowing to optimize away all ompt
1028 // code in this case
1029 template <bool ompt>
1030 static void __kmp_task_finish(kmp_int32 gtid, kmp_task_t *task,
1031                               kmp_taskdata_t *resumed_task) {
1032   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
1033   kmp_info_t *thread = __kmp_threads[gtid];
1034   kmp_task_team_t *task_team =
1035       thread->th.th_task_team; // might be NULL for serial teams...
1036 #if OMPX_TASKGRAPH
1037   // to avoid seg fault when we need to access taskdata->td_flags after free when using vanilla taskloop
1038   bool is_taskgraph;
1039 #endif
1040 #if KMP_DEBUG
1041   kmp_int32 children = 0;
1042 #endif
1043   KA_TRACE(10, ("__kmp_task_finish(enter): T#%d finishing task %p and resuming "
1044                 "task %p\n",
1045                 gtid, taskdata, resumed_task));
1046 
1047   KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
1048 
1049 #if OMPX_TASKGRAPH
1050   is_taskgraph = taskdata->is_taskgraph;
1051 #endif
1052 
1053 // Pop task from stack if tied
1054 #ifdef BUILD_TIED_TASK_STACK
1055   if (taskdata->td_flags.tiedness == TASK_TIED) {
1056     __kmp_pop_task_stack(gtid, thread, taskdata);
1057   }
1058 #endif /* BUILD_TIED_TASK_STACK */
1059 
1060   if (UNLIKELY(taskdata->td_flags.tiedness == TASK_UNTIED)) {
1061     // untied task needs to check the counter so that the task structure is not
1062     // freed prematurely
1063     kmp_int32 counter = KMP_ATOMIC_DEC(&taskdata->td_untied_count) - 1;
1064     KA_TRACE(
1065         20,
1066         ("__kmp_task_finish: T#%d untied_count (%d) decremented for task %p\n",
1067          gtid, counter, taskdata));
1068     if (counter > 0) {
1069       // untied task is not done, to be continued possibly by other thread, do
1070       // not free it now
1071       if (resumed_task == NULL) {
1072         KMP_DEBUG_ASSERT(taskdata->td_flags.task_serial);
1073         resumed_task = taskdata->td_parent; // In a serialized task, the resumed
1074         // task is the parent
1075       }
1076       thread->th.th_current_task = resumed_task; // restore current_task
1077       resumed_task->td_flags.executing = 1; // resume previous task
1078       KA_TRACE(10, ("__kmp_task_finish(exit): T#%d partially done task %p, "
1079                     "resuming task %p\n",
1080                     gtid, taskdata, resumed_task));
1081       return;
1082     }
1083   }
1084 
1085   // bookkeeping for resuming task:
1086   // GEH - note tasking_ser => task_serial
1087   KMP_DEBUG_ASSERT(
1088       (taskdata->td_flags.tasking_ser || taskdata->td_flags.task_serial) ==
1089       taskdata->td_flags.task_serial);
1090   if (taskdata->td_flags.task_serial) {
1091     if (resumed_task == NULL) {
1092       resumed_task = taskdata->td_parent; // In a serialized task, the resumed
1093       // task is the parent
1094     }
1095   } else {
1096     KMP_DEBUG_ASSERT(resumed_task !=
1097                      NULL); // verify that resumed task is passed as argument
1098   }
1099 
1100   /* If the tasks' destructor thunk flag has been set, we need to invoke the
1101      destructor thunk that has been generated by the compiler. The code is
1102      placed here, since at this point other tasks might have been released
1103      hence overlapping the destructor invocations with some other work in the
1104      released tasks.  The OpenMP spec is not specific on when the destructors
1105      are invoked, so we should be free to choose. */
1106   if (UNLIKELY(taskdata->td_flags.destructors_thunk)) {
1107     kmp_routine_entry_t destr_thunk = task->data1.destructors;
1108     KMP_ASSERT(destr_thunk);
1109     destr_thunk(gtid, task);
1110   }
1111 
1112   KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 0);
1113   KMP_DEBUG_ASSERT(taskdata->td_flags.started == 1);
1114   KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
1115 
1116   bool completed = true;
1117   if (UNLIKELY(taskdata->td_flags.detachable == TASK_DETACHABLE)) {
1118     if (taskdata->td_allow_completion_event.type ==
1119         KMP_EVENT_ALLOW_COMPLETION) {
1120       // event hasn't been fulfilled yet. Try to detach task.
1121       __kmp_acquire_tas_lock(&taskdata->td_allow_completion_event.lock, gtid);
1122       if (taskdata->td_allow_completion_event.type ==
1123           KMP_EVENT_ALLOW_COMPLETION) {
1124         // task finished execution
1125         KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 1);
1126         taskdata->td_flags.executing = 0; // suspend the finishing task
1127 
1128 #if OMPT_SUPPORT
1129         // For a detached task, which is not completed, we switch back
1130         // the omp_fulfill_event signals completion
1131         // locking is necessary to avoid a race with ompt_task_late_fulfill
1132         if (ompt)
1133           __ompt_task_finish(task, resumed_task, ompt_task_detach);
1134 #endif
1135 
1136         // no access to taskdata after this point!
1137         // __kmp_fulfill_event might free taskdata at any time from now
1138 
1139         taskdata->td_flags.proxy = TASK_PROXY; // proxify!
1140         completed = false;
1141       }
1142       __kmp_release_tas_lock(&taskdata->td_allow_completion_event.lock, gtid);
1143     }
1144   }
1145 
1146   // Tasks with valid target async handles must be re-enqueued.
1147   if (taskdata->td_target_data.async_handle != NULL) {
1148     // Note: no need to translate gtid to its shadow. If the current thread is a
1149     // hidden helper one, then the gtid is already correct. Otherwise, hidden
1150     // helper threads are disabled, and gtid refers to a OpenMP thread.
1151     __kmpc_give_task(task, __kmp_tid_from_gtid(gtid));
1152     if (KMP_HIDDEN_HELPER_THREAD(gtid))
1153       __kmp_hidden_helper_worker_thread_signal();
1154     completed = false;
1155   }
1156 
1157   if (completed) {
1158     taskdata->td_flags.complete = 1; // mark the task as completed
1159 #if OMPX_TASKGRAPH
1160     taskdata->td_flags.onced = 1; // mark the task as ran once already
1161 #endif
1162 
1163 #if OMPT_SUPPORT
1164     // This is not a detached task, we are done here
1165     if (ompt)
1166       __ompt_task_finish(task, resumed_task, ompt_task_complete);
1167 #endif
1168     // TODO: What would be the balance between the conditions in the function
1169     // and an atomic operation?
1170     if (__kmp_track_children_task(taskdata)) {
1171       __kmp_release_deps(gtid, taskdata);
1172       // Predecrement simulated by "- 1" calculation
1173 #if KMP_DEBUG
1174       children = -1 +
1175 #endif
1176           KMP_ATOMIC_DEC(&taskdata->td_parent->td_incomplete_child_tasks);
1177       KMP_DEBUG_ASSERT(children >= 0);
1178 #if OMPX_TASKGRAPH
1179       if (taskdata->td_taskgroup && !taskdata->is_taskgraph)
1180 #else
1181       if (taskdata->td_taskgroup)
1182 #endif
1183         KMP_ATOMIC_DEC(&taskdata->td_taskgroup->count);
1184     } else if (task_team && (task_team->tt.tt_found_proxy_tasks ||
1185                              task_team->tt.tt_hidden_helper_task_encountered)) {
1186       // if we found proxy or hidden helper tasks there could exist a dependency
1187       // chain with the proxy task as origin
1188       __kmp_release_deps(gtid, taskdata);
1189     }
1190     // td_flags.executing must be marked as 0 after __kmp_release_deps has been
1191     // called. Othertwise, if a task is executed immediately from the
1192     // release_deps code, the flag will be reset to 1 again by this same
1193     // function
1194     KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 1);
1195     taskdata->td_flags.executing = 0; // suspend the finishing task
1196 
1197     // Decrement the counter of hidden helper tasks to be executed.
1198     if (taskdata->td_flags.hidden_helper) {
1199       // Hidden helper tasks can only be executed by hidden helper threads.
1200       KMP_ASSERT(KMP_HIDDEN_HELPER_THREAD(gtid));
1201       KMP_ATOMIC_DEC(&__kmp_unexecuted_hidden_helper_tasks);
1202     }
1203   }
1204 
1205   KA_TRACE(
1206       20, ("__kmp_task_finish: T#%d finished task %p, %d incomplete children\n",
1207            gtid, taskdata, children));
1208 
1209   // Free this task and then ancestor tasks if they have no children.
1210   // Restore th_current_task first as suggested by John:
1211   // johnmc: if an asynchronous inquiry peers into the runtime system
1212   // it doesn't see the freed task as the current task.
1213   thread->th.th_current_task = resumed_task;
1214   if (completed)
1215     __kmp_free_task_and_ancestors(gtid, taskdata, thread);
1216 
1217   // TODO: GEH - make sure root team implicit task is initialized properly.
1218   // KMP_DEBUG_ASSERT( resumed_task->td_flags.executing == 0 );
1219   resumed_task->td_flags.executing = 1; // resume previous task
1220 
1221 #if OMPX_TASKGRAPH
1222   if (is_taskgraph && __kmp_track_children_task(taskdata) &&
1223       taskdata->td_taskgroup) {
1224     // TDG: we only release taskgroup barrier here because
1225     // free_task_and_ancestors will call
1226     // __kmp_free_task, which resets all task parameters such as
1227     // taskdata->started, etc. If we release the barrier earlier, these
1228     // parameters could be read before being reset. This is not an issue for
1229     // non-TDG implementation because we never reuse a task(data) structure
1230     KMP_ATOMIC_DEC(&taskdata->td_taskgroup->count);
1231   }
1232 #endif
1233 
1234   KA_TRACE(
1235       10, ("__kmp_task_finish(exit): T#%d finished task %p, resuming task %p\n",
1236            gtid, taskdata, resumed_task));
1237 
1238   return;
1239 }
1240 
1241 template <bool ompt>
1242 static void __kmpc_omp_task_complete_if0_template(ident_t *loc_ref,
1243                                                   kmp_int32 gtid,
1244                                                   kmp_task_t *task) {
1245   KA_TRACE(10, ("__kmpc_omp_task_complete_if0(enter): T#%d loc=%p task=%p\n",
1246                 gtid, loc_ref, KMP_TASK_TO_TASKDATA(task)));
1247   KMP_DEBUG_ASSERT(gtid >= 0);
1248   // this routine will provide task to resume
1249   __kmp_task_finish<ompt>(gtid, task, NULL);
1250 
1251   KA_TRACE(10, ("__kmpc_omp_task_complete_if0(exit): T#%d loc=%p task=%p\n",
1252                 gtid, loc_ref, KMP_TASK_TO_TASKDATA(task)));
1253 
1254 #if OMPT_SUPPORT
1255   if (ompt) {
1256     ompt_frame_t *ompt_frame;
1257     __ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
1258     ompt_frame->enter_frame = ompt_data_none;
1259     ompt_frame->enter_frame_flags =
1260         ompt_frame_runtime | ompt_frame_framepointer;
1261   }
1262 #endif
1263 
1264   return;
1265 }
1266 
1267 #if OMPT_SUPPORT
1268 OMPT_NOINLINE
1269 void __kmpc_omp_task_complete_if0_ompt(ident_t *loc_ref, kmp_int32 gtid,
1270                                        kmp_task_t *task) {
1271   __kmpc_omp_task_complete_if0_template<true>(loc_ref, gtid, task);
1272 }
1273 #endif // OMPT_SUPPORT
1274 
1275 // __kmpc_omp_task_complete_if0: report that a task has completed execution
1276 //
1277 // loc_ref: source location information; points to end of task block.
1278 // gtid: global thread number.
1279 // task: task thunk for the completed task.
1280 void __kmpc_omp_task_complete_if0(ident_t *loc_ref, kmp_int32 gtid,
1281                                   kmp_task_t *task) {
1282 #if OMPT_SUPPORT
1283   if (UNLIKELY(ompt_enabled.enabled)) {
1284     __kmpc_omp_task_complete_if0_ompt(loc_ref, gtid, task);
1285     return;
1286   }
1287 #endif
1288   __kmpc_omp_task_complete_if0_template<false>(loc_ref, gtid, task);
1289 }
1290 
1291 #ifdef TASK_UNUSED
1292 // __kmpc_omp_task_complete: report that a task has completed execution
1293 // NEVER GENERATED BY COMPILER, DEPRECATED!!!
1294 void __kmpc_omp_task_complete(ident_t *loc_ref, kmp_int32 gtid,
1295                               kmp_task_t *task) {
1296   KA_TRACE(10, ("__kmpc_omp_task_complete(enter): T#%d loc=%p task=%p\n", gtid,
1297                 loc_ref, KMP_TASK_TO_TASKDATA(task)));
1298 
1299   __kmp_task_finish<false>(gtid, task,
1300                            NULL); // Not sure how to find task to resume
1301 
1302   KA_TRACE(10, ("__kmpc_omp_task_complete(exit): T#%d loc=%p task=%p\n", gtid,
1303                 loc_ref, KMP_TASK_TO_TASKDATA(task)));
1304   return;
1305 }
1306 #endif // TASK_UNUSED
1307 
1308 // __kmp_init_implicit_task: Initialize the appropriate fields in the implicit
1309 // task for a given thread
1310 //
1311 // loc_ref:  reference to source location of parallel region
1312 // this_thr:  thread data structure corresponding to implicit task
1313 // team: team for this_thr
1314 // tid: thread id of given thread within team
1315 // set_curr_task: TRUE if need to push current task to thread
1316 // NOTE: Routine does not set up the implicit task ICVS.  This is assumed to
1317 // have already been done elsewhere.
1318 // TODO: Get better loc_ref.  Value passed in may be NULL
1319 void __kmp_init_implicit_task(ident_t *loc_ref, kmp_info_t *this_thr,
1320                               kmp_team_t *team, int tid, int set_curr_task) {
1321   kmp_taskdata_t *task = &team->t.t_implicit_task_taskdata[tid];
1322 
1323   KF_TRACE(
1324       10,
1325       ("__kmp_init_implicit_task(enter): T#:%d team=%p task=%p, reinit=%s\n",
1326        tid, team, task, set_curr_task ? "TRUE" : "FALSE"));
1327 
1328   task->td_task_id = KMP_GEN_TASK_ID();
1329   task->td_team = team;
1330   //    task->td_parent   = NULL;  // fix for CQ230101 (broken parent task info
1331   //    in debugger)
1332   task->td_ident = loc_ref;
1333   task->td_taskwait_ident = NULL;
1334   task->td_taskwait_counter = 0;
1335   task->td_taskwait_thread = 0;
1336 
1337   task->td_flags.tiedness = TASK_TIED;
1338   task->td_flags.tasktype = TASK_IMPLICIT;
1339   task->td_flags.proxy = TASK_FULL;
1340 
1341   // All implicit tasks are executed immediately, not deferred
1342   task->td_flags.task_serial = 1;
1343   task->td_flags.tasking_ser = (__kmp_tasking_mode == tskm_immediate_exec);
1344   task->td_flags.team_serial = (team->t.t_serialized) ? 1 : 0;
1345 
1346   task->td_flags.started = 1;
1347   task->td_flags.executing = 1;
1348   task->td_flags.complete = 0;
1349   task->td_flags.freed = 0;
1350 #if OMPX_TASKGRAPH
1351   task->td_flags.onced = 0;
1352 #endif
1353 
1354   task->td_depnode = NULL;
1355   task->td_last_tied = task;
1356   task->td_allow_completion_event.type = KMP_EVENT_UNINITIALIZED;
1357 
1358   if (set_curr_task) { // only do this init first time thread is created
1359     KMP_ATOMIC_ST_REL(&task->td_incomplete_child_tasks, 0);
1360     // Not used: don't need to deallocate implicit task
1361     KMP_ATOMIC_ST_REL(&task->td_allocated_child_tasks, 0);
1362     task->td_taskgroup = NULL; // An implicit task does not have taskgroup
1363     task->td_dephash = NULL;
1364     __kmp_push_current_task_to_thread(this_thr, team, tid);
1365   } else {
1366     KMP_DEBUG_ASSERT(task->td_incomplete_child_tasks == 0);
1367     KMP_DEBUG_ASSERT(task->td_allocated_child_tasks == 0);
1368   }
1369 
1370 #if OMPT_SUPPORT
1371   if (UNLIKELY(ompt_enabled.enabled))
1372     __ompt_task_init(task, tid);
1373 #endif
1374 
1375   KF_TRACE(10, ("__kmp_init_implicit_task(exit): T#:%d team=%p task=%p\n", tid,
1376                 team, task));
1377 }
1378 
1379 // __kmp_finish_implicit_task: Release resources associated to implicit tasks
1380 // at the end of parallel regions. Some resources are kept for reuse in the next
1381 // parallel region.
1382 //
1383 // thread:  thread data structure corresponding to implicit task
1384 void __kmp_finish_implicit_task(kmp_info_t *thread) {
1385   kmp_taskdata_t *task = thread->th.th_current_task;
1386   if (task->td_dephash) {
1387     int children;
1388     task->td_flags.complete = 1;
1389 #if OMPX_TASKGRAPH
1390     task->td_flags.onced = 1;
1391 #endif
1392     children = KMP_ATOMIC_LD_ACQ(&task->td_incomplete_child_tasks);
1393     kmp_tasking_flags_t flags_old = task->td_flags;
1394     if (children == 0 && flags_old.complete == 1) {
1395       kmp_tasking_flags_t flags_new = flags_old;
1396       flags_new.complete = 0;
1397       if (KMP_COMPARE_AND_STORE_ACQ32(RCAST(kmp_int32 *, &task->td_flags),
1398                                       *RCAST(kmp_int32 *, &flags_old),
1399                                       *RCAST(kmp_int32 *, &flags_new))) {
1400         KA_TRACE(100, ("__kmp_finish_implicit_task: T#%d cleans "
1401                        "dephash of implicit task %p\n",
1402                        thread->th.th_info.ds.ds_gtid, task));
1403         __kmp_dephash_free_entries(thread, task->td_dephash);
1404       }
1405     }
1406   }
1407 }
1408 
1409 // __kmp_free_implicit_task: Release resources associated to implicit tasks
1410 // when these are destroyed regions
1411 //
1412 // thread:  thread data structure corresponding to implicit task
1413 void __kmp_free_implicit_task(kmp_info_t *thread) {
1414   kmp_taskdata_t *task = thread->th.th_current_task;
1415   if (task && task->td_dephash) {
1416     __kmp_dephash_free(thread, task->td_dephash);
1417     task->td_dephash = NULL;
1418   }
1419 }
1420 
1421 // Round up a size to a power of two specified by val: Used to insert padding
1422 // between structures co-allocated using a single malloc() call
1423 static size_t __kmp_round_up_to_val(size_t size, size_t val) {
1424   if (size & (val - 1)) {
1425     size &= ~(val - 1);
1426     if (size <= KMP_SIZE_T_MAX - val) {
1427       size += val; // Round up if there is no overflow.
1428     }
1429   }
1430   return size;
1431 } // __kmp_round_up_to_va
1432 
1433 // __kmp_task_alloc: Allocate the taskdata and task data structures for a task
1434 //
1435 // loc_ref: source location information
1436 // gtid: global thread number.
1437 // flags: include tiedness & task type (explicit vs. implicit) of the ''new''
1438 // task encountered. Converted from kmp_int32 to kmp_tasking_flags_t in routine.
1439 // sizeof_kmp_task_t:  Size in bytes of kmp_task_t data structure including
1440 // private vars accessed in task.
1441 // sizeof_shareds:  Size in bytes of array of pointers to shared vars accessed
1442 // in task.
1443 // task_entry: Pointer to task code entry point generated by compiler.
1444 // returns: a pointer to the allocated kmp_task_t structure (task).
1445 kmp_task_t *__kmp_task_alloc(ident_t *loc_ref, kmp_int32 gtid,
1446                              kmp_tasking_flags_t *flags,
1447                              size_t sizeof_kmp_task_t, size_t sizeof_shareds,
1448                              kmp_routine_entry_t task_entry) {
1449   kmp_task_t *task;
1450   kmp_taskdata_t *taskdata;
1451   kmp_info_t *thread = __kmp_threads[gtid];
1452   kmp_team_t *team = thread->th.th_team;
1453   kmp_taskdata_t *parent_task = thread->th.th_current_task;
1454   size_t shareds_offset;
1455 
1456   if (UNLIKELY(!TCR_4(__kmp_init_middle)))
1457     __kmp_middle_initialize();
1458 
1459   if (flags->hidden_helper) {
1460     if (__kmp_enable_hidden_helper) {
1461       if (!TCR_4(__kmp_init_hidden_helper))
1462         __kmp_hidden_helper_initialize();
1463     } else {
1464       // If the hidden helper task is not enabled, reset the flag to FALSE.
1465       flags->hidden_helper = FALSE;
1466     }
1467   }
1468 
1469   KA_TRACE(10, ("__kmp_task_alloc(enter): T#%d loc=%p, flags=(0x%x) "
1470                 "sizeof_task=%ld sizeof_shared=%ld entry=%p\n",
1471                 gtid, loc_ref, *((kmp_int32 *)flags), sizeof_kmp_task_t,
1472                 sizeof_shareds, task_entry));
1473 
1474   KMP_DEBUG_ASSERT(parent_task);
1475   if (parent_task->td_flags.final) {
1476     if (flags->merged_if0) {
1477     }
1478     flags->final = 1;
1479   }
1480 
1481   if (flags->tiedness == TASK_UNTIED && !team->t.t_serialized) {
1482     // Untied task encountered causes the TSC algorithm to check entire deque of
1483     // the victim thread. If no untied task encountered, then checking the head
1484     // of the deque should be enough.
1485     KMP_CHECK_UPDATE(thread->th.th_task_team->tt.tt_untied_task_encountered, 1);
1486   }
1487 
1488   // Detachable tasks are not proxy tasks yet but could be in the future. Doing
1489   // the tasking setup
1490   // when that happens is too late.
1491   if (UNLIKELY(flags->proxy == TASK_PROXY ||
1492                flags->detachable == TASK_DETACHABLE || flags->hidden_helper)) {
1493     if (flags->proxy == TASK_PROXY) {
1494       flags->tiedness = TASK_UNTIED;
1495       flags->merged_if0 = 1;
1496     }
1497     /* are we running in a sequential parallel or tskm_immediate_exec... we need
1498        tasking support enabled */
1499     if ((thread->th.th_task_team) == NULL) {
1500       /* This should only happen if the team is serialized
1501           setup a task team and propagate it to the thread */
1502       KMP_DEBUG_ASSERT(team->t.t_serialized);
1503       KA_TRACE(30,
1504                ("T#%d creating task team in __kmp_task_alloc for proxy task\n",
1505                 gtid));
1506       // 1 indicates setup the current team regardless of nthreads
1507       __kmp_task_team_setup(thread, team, 1);
1508       thread->th.th_task_team = team->t.t_task_team[thread->th.th_task_state];
1509     }
1510     kmp_task_team_t *task_team = thread->th.th_task_team;
1511 
1512     /* tasking must be enabled now as the task might not be pushed */
1513     if (!KMP_TASKING_ENABLED(task_team)) {
1514       KA_TRACE(
1515           30,
1516           ("T#%d enabling tasking in __kmp_task_alloc for proxy task\n", gtid));
1517       __kmp_enable_tasking(task_team, thread);
1518       kmp_int32 tid = thread->th.th_info.ds.ds_tid;
1519       kmp_thread_data_t *thread_data = &task_team->tt.tt_threads_data[tid];
1520       // No lock needed since only owner can allocate
1521       if (thread_data->td.td_deque == NULL) {
1522         __kmp_alloc_task_deque(thread, thread_data);
1523       }
1524     }
1525 
1526     if ((flags->proxy == TASK_PROXY || flags->detachable == TASK_DETACHABLE) &&
1527         task_team->tt.tt_found_proxy_tasks == FALSE)
1528       TCW_4(task_team->tt.tt_found_proxy_tasks, TRUE);
1529     if (flags->hidden_helper &&
1530         task_team->tt.tt_hidden_helper_task_encountered == FALSE)
1531       TCW_4(task_team->tt.tt_hidden_helper_task_encountered, TRUE);
1532   }
1533 
1534   // Calculate shared structure offset including padding after kmp_task_t struct
1535   // to align pointers in shared struct
1536   shareds_offset = sizeof(kmp_taskdata_t) + sizeof_kmp_task_t;
1537   shareds_offset = __kmp_round_up_to_val(shareds_offset, sizeof(void *));
1538 
1539   // Allocate a kmp_taskdata_t block and a kmp_task_t block.
1540   KA_TRACE(30, ("__kmp_task_alloc: T#%d First malloc size: %ld\n", gtid,
1541                 shareds_offset));
1542   KA_TRACE(30, ("__kmp_task_alloc: T#%d Second malloc size: %ld\n", gtid,
1543                 sizeof_shareds));
1544 
1545   // Avoid double allocation here by combining shareds with taskdata
1546 #if USE_FAST_MEMORY
1547   taskdata = (kmp_taskdata_t *)__kmp_fast_allocate(thread, shareds_offset +
1548                                                                sizeof_shareds);
1549 #else /* ! USE_FAST_MEMORY */
1550   taskdata = (kmp_taskdata_t *)__kmp_thread_malloc(thread, shareds_offset +
1551                                                                sizeof_shareds);
1552 #endif /* USE_FAST_MEMORY */
1553 
1554   task = KMP_TASKDATA_TO_TASK(taskdata);
1555 
1556 // Make sure task & taskdata are aligned appropriately
1557 #if KMP_ARCH_X86 || KMP_ARCH_PPC64 || !KMP_HAVE_QUAD
1558   KMP_DEBUG_ASSERT((((kmp_uintptr_t)taskdata) & (sizeof(double) - 1)) == 0);
1559   KMP_DEBUG_ASSERT((((kmp_uintptr_t)task) & (sizeof(double) - 1)) == 0);
1560 #else
1561   KMP_DEBUG_ASSERT((((kmp_uintptr_t)taskdata) & (sizeof(_Quad) - 1)) == 0);
1562   KMP_DEBUG_ASSERT((((kmp_uintptr_t)task) & (sizeof(_Quad) - 1)) == 0);
1563 #endif
1564   if (sizeof_shareds > 0) {
1565     // Avoid double allocation here by combining shareds with taskdata
1566     task->shareds = &((char *)taskdata)[shareds_offset];
1567     // Make sure shareds struct is aligned to pointer size
1568     KMP_DEBUG_ASSERT((((kmp_uintptr_t)task->shareds) & (sizeof(void *) - 1)) ==
1569                      0);
1570   } else {
1571     task->shareds = NULL;
1572   }
1573   task->routine = task_entry;
1574   task->part_id = 0; // AC: Always start with 0 part id
1575 
1576   taskdata->td_task_id = KMP_GEN_TASK_ID();
1577   taskdata->td_team = thread->th.th_team;
1578   taskdata->td_alloc_thread = thread;
1579   taskdata->td_parent = parent_task;
1580   taskdata->td_level = parent_task->td_level + 1; // increment nesting level
1581   KMP_ATOMIC_ST_RLX(&taskdata->td_untied_count, 0);
1582   taskdata->td_ident = loc_ref;
1583   taskdata->td_taskwait_ident = NULL;
1584   taskdata->td_taskwait_counter = 0;
1585   taskdata->td_taskwait_thread = 0;
1586   KMP_DEBUG_ASSERT(taskdata->td_parent != NULL);
1587   // avoid copying icvs for proxy tasks
1588   if (flags->proxy == TASK_FULL)
1589     copy_icvs(&taskdata->td_icvs, &taskdata->td_parent->td_icvs);
1590 
1591   taskdata->td_flags = *flags;
1592   taskdata->td_task_team = thread->th.th_task_team;
1593   taskdata->td_size_alloc = shareds_offset + sizeof_shareds;
1594   taskdata->td_flags.tasktype = TASK_EXPLICIT;
1595   // If it is hidden helper task, we need to set the team and task team
1596   // correspondingly.
1597   if (flags->hidden_helper) {
1598     kmp_info_t *shadow_thread = __kmp_threads[KMP_GTID_TO_SHADOW_GTID(gtid)];
1599     taskdata->td_team = shadow_thread->th.th_team;
1600     taskdata->td_task_team = shadow_thread->th.th_task_team;
1601   }
1602 
1603   // GEH - TODO: fix this to copy parent task's value of tasking_ser flag
1604   taskdata->td_flags.tasking_ser = (__kmp_tasking_mode == tskm_immediate_exec);
1605 
1606   // GEH - TODO: fix this to copy parent task's value of team_serial flag
1607   taskdata->td_flags.team_serial = (team->t.t_serialized) ? 1 : 0;
1608 
1609   // GEH - Note we serialize the task if the team is serialized to make sure
1610   // implicit parallel region tasks are not left until program termination to
1611   // execute. Also, it helps locality to execute immediately.
1612 
1613   taskdata->td_flags.task_serial =
1614       (parent_task->td_flags.final || taskdata->td_flags.team_serial ||
1615        taskdata->td_flags.tasking_ser || flags->merged_if0);
1616 
1617   taskdata->td_flags.started = 0;
1618   taskdata->td_flags.executing = 0;
1619   taskdata->td_flags.complete = 0;
1620   taskdata->td_flags.freed = 0;
1621 #if OMPX_TASKGRAPH
1622   taskdata->td_flags.onced = 0;
1623 #endif
1624   KMP_ATOMIC_ST_RLX(&taskdata->td_incomplete_child_tasks, 0);
1625   // start at one because counts current task and children
1626   KMP_ATOMIC_ST_RLX(&taskdata->td_allocated_child_tasks, 1);
1627   taskdata->td_taskgroup =
1628       parent_task->td_taskgroup; // task inherits taskgroup from the parent task
1629   taskdata->td_dephash = NULL;
1630   taskdata->td_depnode = NULL;
1631   taskdata->td_target_data.async_handle = NULL;
1632   if (flags->tiedness == TASK_UNTIED)
1633     taskdata->td_last_tied = NULL; // will be set when the task is scheduled
1634   else
1635     taskdata->td_last_tied = taskdata;
1636   taskdata->td_allow_completion_event.type = KMP_EVENT_UNINITIALIZED;
1637 #if OMPT_SUPPORT
1638   if (UNLIKELY(ompt_enabled.enabled))
1639     __ompt_task_init(taskdata, gtid);
1640 #endif
1641   // TODO: What would be the balance between the conditions in the function and
1642   // an atomic operation?
1643   if (__kmp_track_children_task(taskdata)) {
1644     KMP_ATOMIC_INC(&parent_task->td_incomplete_child_tasks);
1645     if (parent_task->td_taskgroup)
1646       KMP_ATOMIC_INC(&parent_task->td_taskgroup->count);
1647     // Only need to keep track of allocated child tasks for explicit tasks since
1648     // implicit not deallocated
1649     if (taskdata->td_parent->td_flags.tasktype == TASK_EXPLICIT) {
1650       KMP_ATOMIC_INC(&taskdata->td_parent->td_allocated_child_tasks);
1651     }
1652     if (flags->hidden_helper) {
1653       taskdata->td_flags.task_serial = FALSE;
1654       // Increment the number of hidden helper tasks to be executed
1655       KMP_ATOMIC_INC(&__kmp_unexecuted_hidden_helper_tasks);
1656     }
1657   }
1658 
1659 #if OMPX_TASKGRAPH
1660   kmp_tdg_info_t *tdg = __kmp_find_tdg(__kmp_curr_tdg_idx);
1661   if (tdg && __kmp_tdg_is_recording(tdg->tdg_status) &&
1662       (task_entry != (kmp_routine_entry_t)__kmp_taskloop_task)) {
1663     taskdata->is_taskgraph = 1;
1664     taskdata->tdg = __kmp_global_tdgs[__kmp_curr_tdg_idx];
1665     taskdata->td_task_id = KMP_ATOMIC_INC(&__kmp_tdg_task_id);
1666   }
1667 #endif
1668   KA_TRACE(20, ("__kmp_task_alloc(exit): T#%d created task %p parent=%p\n",
1669                 gtid, taskdata, taskdata->td_parent));
1670 
1671   return task;
1672 }
1673 
1674 kmp_task_t *__kmpc_omp_task_alloc(ident_t *loc_ref, kmp_int32 gtid,
1675                                   kmp_int32 flags, size_t sizeof_kmp_task_t,
1676                                   size_t sizeof_shareds,
1677                                   kmp_routine_entry_t task_entry) {
1678   kmp_task_t *retval;
1679   kmp_tasking_flags_t *input_flags = (kmp_tasking_flags_t *)&flags;
1680   __kmp_assert_valid_gtid(gtid);
1681   input_flags->native = FALSE;
1682   // __kmp_task_alloc() sets up all other runtime flags
1683   KA_TRACE(10, ("__kmpc_omp_task_alloc(enter): T#%d loc=%p, flags=(%s %s %s) "
1684                 "sizeof_task=%ld sizeof_shared=%ld entry=%p\n",
1685                 gtid, loc_ref, input_flags->tiedness ? "tied  " : "untied",
1686                 input_flags->proxy ? "proxy" : "",
1687                 input_flags->detachable ? "detachable" : "", sizeof_kmp_task_t,
1688                 sizeof_shareds, task_entry));
1689 
1690   retval = __kmp_task_alloc(loc_ref, gtid, input_flags, sizeof_kmp_task_t,
1691                             sizeof_shareds, task_entry);
1692 
1693   KA_TRACE(20, ("__kmpc_omp_task_alloc(exit): T#%d retval %p\n", gtid, retval));
1694 
1695   return retval;
1696 }
1697 
1698 kmp_task_t *__kmpc_omp_target_task_alloc(ident_t *loc_ref, kmp_int32 gtid,
1699                                          kmp_int32 flags,
1700                                          size_t sizeof_kmp_task_t,
1701                                          size_t sizeof_shareds,
1702                                          kmp_routine_entry_t task_entry,
1703                                          kmp_int64 device_id) {
1704   auto &input_flags = reinterpret_cast<kmp_tasking_flags_t &>(flags);
1705   // target task is untied defined in the specification
1706   input_flags.tiedness = TASK_UNTIED;
1707 
1708   if (__kmp_enable_hidden_helper)
1709     input_flags.hidden_helper = TRUE;
1710 
1711   return __kmpc_omp_task_alloc(loc_ref, gtid, flags, sizeof_kmp_task_t,
1712                                sizeof_shareds, task_entry);
1713 }
1714 
1715 /*!
1716 @ingroup TASKING
1717 @param loc_ref location of the original task directive
1718 @param gtid Global Thread ID of encountering thread
1719 @param new_task task thunk allocated by __kmpc_omp_task_alloc() for the ''new
1720 task''
1721 @param naffins Number of affinity items
1722 @param affin_list List of affinity items
1723 @return Returns non-zero if registering affinity information was not successful.
1724  Returns 0 if registration was successful
1725 This entry registers the affinity information attached to a task with the task
1726 thunk structure kmp_taskdata_t.
1727 */
1728 kmp_int32
1729 __kmpc_omp_reg_task_with_affinity(ident_t *loc_ref, kmp_int32 gtid,
1730                                   kmp_task_t *new_task, kmp_int32 naffins,
1731                                   kmp_task_affinity_info_t *affin_list) {
1732   return 0;
1733 }
1734 
1735 //  __kmp_invoke_task: invoke the specified task
1736 //
1737 // gtid: global thread ID of caller
1738 // task: the task to invoke
1739 // current_task: the task to resume after task invocation
1740 static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
1741                               kmp_taskdata_t *current_task) {
1742   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
1743   kmp_info_t *thread;
1744   int discard = 0 /* false */;
1745   KA_TRACE(
1746       30, ("__kmp_invoke_task(enter): T#%d invoking task %p, current_task=%p\n",
1747            gtid, taskdata, current_task));
1748   KMP_DEBUG_ASSERT(task);
1749   if (UNLIKELY(taskdata->td_flags.proxy == TASK_PROXY &&
1750                taskdata->td_flags.complete == 1)) {
1751     // This is a proxy task that was already completed but it needs to run
1752     // its bottom-half finish
1753     KA_TRACE(
1754         30,
1755         ("__kmp_invoke_task: T#%d running bottom finish for proxy task %p\n",
1756          gtid, taskdata));
1757 
1758     __kmp_bottom_half_finish_proxy(gtid, task);
1759 
1760     KA_TRACE(30, ("__kmp_invoke_task(exit): T#%d completed bottom finish for "
1761                   "proxy task %p, resuming task %p\n",
1762                   gtid, taskdata, current_task));
1763 
1764     return;
1765   }
1766 
1767 #if OMPT_SUPPORT
1768   // For untied tasks, the first task executed only calls __kmpc_omp_task and
1769   // does not execute code.
1770   ompt_thread_info_t oldInfo;
1771   if (UNLIKELY(ompt_enabled.enabled)) {
1772     // Store the threads states and restore them after the task
1773     thread = __kmp_threads[gtid];
1774     oldInfo = thread->th.ompt_thread_info;
1775     thread->th.ompt_thread_info.wait_id = 0;
1776     thread->th.ompt_thread_info.state = (thread->th.th_team_serialized)
1777                                             ? ompt_state_work_serial
1778                                             : ompt_state_work_parallel;
1779     taskdata->ompt_task_info.frame.exit_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
1780   }
1781 #endif
1782 
1783   // Proxy tasks are not handled by the runtime
1784   if (taskdata->td_flags.proxy != TASK_PROXY) {
1785     __kmp_task_start(gtid, task, current_task); // OMPT only if not discarded
1786   }
1787 
1788   // TODO: cancel tasks if the parallel region has also been cancelled
1789   // TODO: check if this sequence can be hoisted above __kmp_task_start
1790   // if cancellation has been enabled for this run ...
1791   if (UNLIKELY(__kmp_omp_cancellation)) {
1792     thread = __kmp_threads[gtid];
1793     kmp_team_t *this_team = thread->th.th_team;
1794     kmp_taskgroup_t *taskgroup = taskdata->td_taskgroup;
1795     if ((taskgroup && taskgroup->cancel_request) ||
1796         (this_team->t.t_cancel_request == cancel_parallel)) {
1797 #if OMPT_SUPPORT && OMPT_OPTIONAL
1798       ompt_data_t *task_data;
1799       if (UNLIKELY(ompt_enabled.ompt_callback_cancel)) {
1800         __ompt_get_task_info_internal(0, NULL, &task_data, NULL, NULL, NULL);
1801         ompt_callbacks.ompt_callback(ompt_callback_cancel)(
1802             task_data,
1803             ((taskgroup && taskgroup->cancel_request) ? ompt_cancel_taskgroup
1804                                                       : ompt_cancel_parallel) |
1805                 ompt_cancel_discarded_task,
1806             NULL);
1807       }
1808 #endif
1809       KMP_COUNT_BLOCK(TASK_cancelled);
1810       // this task belongs to a task group and we need to cancel it
1811       discard = 1 /* true */;
1812     }
1813   }
1814 
1815   // Invoke the task routine and pass in relevant data.
1816   // Thunks generated by gcc take a different argument list.
1817   if (!discard) {
1818     if (taskdata->td_flags.tiedness == TASK_UNTIED) {
1819       taskdata->td_last_tied = current_task->td_last_tied;
1820       KMP_DEBUG_ASSERT(taskdata->td_last_tied);
1821     }
1822 #if KMP_STATS_ENABLED
1823     KMP_COUNT_BLOCK(TASK_executed);
1824     switch (KMP_GET_THREAD_STATE()) {
1825     case FORK_JOIN_BARRIER:
1826       KMP_PUSH_PARTITIONED_TIMER(OMP_task_join_bar);
1827       break;
1828     case PLAIN_BARRIER:
1829       KMP_PUSH_PARTITIONED_TIMER(OMP_task_plain_bar);
1830       break;
1831     case TASKYIELD:
1832       KMP_PUSH_PARTITIONED_TIMER(OMP_task_taskyield);
1833       break;
1834     case TASKWAIT:
1835       KMP_PUSH_PARTITIONED_TIMER(OMP_task_taskwait);
1836       break;
1837     case TASKGROUP:
1838       KMP_PUSH_PARTITIONED_TIMER(OMP_task_taskgroup);
1839       break;
1840     default:
1841       KMP_PUSH_PARTITIONED_TIMER(OMP_task_immediate);
1842       break;
1843     }
1844 #endif // KMP_STATS_ENABLED
1845 
1846 // OMPT task begin
1847 #if OMPT_SUPPORT
1848     if (UNLIKELY(ompt_enabled.enabled))
1849       __ompt_task_start(task, current_task, gtid);
1850 #endif
1851 #if OMPT_SUPPORT && OMPT_OPTIONAL
1852     if (UNLIKELY(ompt_enabled.ompt_callback_dispatch &&
1853                  taskdata->ompt_task_info.dispatch_chunk.iterations > 0)) {
1854       ompt_data_t instance = ompt_data_none;
1855       instance.ptr = &(taskdata->ompt_task_info.dispatch_chunk);
1856       ompt_team_info_t *team_info = __ompt_get_teaminfo(0, NULL);
1857       ompt_callbacks.ompt_callback(ompt_callback_dispatch)(
1858           &(team_info->parallel_data), &(taskdata->ompt_task_info.task_data),
1859           ompt_dispatch_taskloop_chunk, instance);
1860       taskdata->ompt_task_info.dispatch_chunk = {0, 0};
1861     }
1862 #endif // OMPT_SUPPORT && OMPT_OPTIONAL
1863 
1864 #if OMPD_SUPPORT
1865     if (ompd_state & OMPD_ENABLE_BP)
1866       ompd_bp_task_begin();
1867 #endif
1868 
1869 #if USE_ITT_BUILD && USE_ITT_NOTIFY
1870     kmp_uint64 cur_time;
1871     kmp_int32 kmp_itt_count_task =
1872         __kmp_forkjoin_frames_mode == 3 && !taskdata->td_flags.task_serial &&
1873         current_task->td_flags.tasktype == TASK_IMPLICIT;
1874     if (kmp_itt_count_task) {
1875       thread = __kmp_threads[gtid];
1876       // Time outer level explicit task on barrier for adjusting imbalance time
1877       if (thread->th.th_bar_arrive_time)
1878         cur_time = __itt_get_timestamp();
1879       else
1880         kmp_itt_count_task = 0; // thread is not on a barrier - skip timing
1881     }
1882     KMP_FSYNC_ACQUIRED(taskdata); // acquired self (new task)
1883 #endif
1884 
1885 #if ENABLE_LIBOMPTARGET
1886     if (taskdata->td_target_data.async_handle != NULL) {
1887       // If we have a valid target async handle, that means that we have already
1888       // executed the task routine once. We must query for the handle completion
1889       // instead of re-executing the routine.
1890       KMP_ASSERT(tgt_target_nowait_query);
1891       tgt_target_nowait_query(&taskdata->td_target_data.async_handle);
1892     } else
1893 #endif
1894     if (task->routine != NULL) {
1895 #ifdef KMP_GOMP_COMPAT
1896       if (taskdata->td_flags.native) {
1897         ((void (*)(void *))(*(task->routine)))(task->shareds);
1898       } else
1899 #endif /* KMP_GOMP_COMPAT */
1900       {
1901         (*(task->routine))(gtid, task);
1902       }
1903     }
1904     KMP_POP_PARTITIONED_TIMER();
1905 
1906 #if USE_ITT_BUILD && USE_ITT_NOTIFY
1907     if (kmp_itt_count_task) {
1908       // Barrier imbalance - adjust arrive time with the task duration
1909       thread->th.th_bar_arrive_time += (__itt_get_timestamp() - cur_time);
1910     }
1911     KMP_FSYNC_CANCEL(taskdata); // destroy self (just executed)
1912     KMP_FSYNC_RELEASING(taskdata->td_parent); // releasing parent
1913 #endif
1914   }
1915 
1916 #if OMPD_SUPPORT
1917   if (ompd_state & OMPD_ENABLE_BP)
1918     ompd_bp_task_end();
1919 #endif
1920 
1921   // Proxy tasks are not handled by the runtime
1922   if (taskdata->td_flags.proxy != TASK_PROXY) {
1923 #if OMPT_SUPPORT
1924     if (UNLIKELY(ompt_enabled.enabled)) {
1925       thread->th.ompt_thread_info = oldInfo;
1926       if (taskdata->td_flags.tiedness == TASK_TIED) {
1927         taskdata->ompt_task_info.frame.exit_frame = ompt_data_none;
1928       }
1929       __kmp_task_finish<true>(gtid, task, current_task);
1930     } else
1931 #endif
1932       __kmp_task_finish<false>(gtid, task, current_task);
1933   }
1934 
1935   KA_TRACE(
1936       30,
1937       ("__kmp_invoke_task(exit): T#%d completed task %p, resuming task %p\n",
1938        gtid, taskdata, current_task));
1939   return;
1940 }
1941 
1942 // __kmpc_omp_task_parts: Schedule a thread-switchable task for execution
1943 //
1944 // loc_ref: location of original task pragma (ignored)
1945 // gtid: Global Thread ID of encountering thread
1946 // new_task: task thunk allocated by __kmp_omp_task_alloc() for the ''new task''
1947 // Returns:
1948 //    TASK_CURRENT_NOT_QUEUED (0) if did not suspend and queue current task to
1949 //    be resumed later.
1950 //    TASK_CURRENT_QUEUED (1) if suspended and queued the current task to be
1951 //    resumed later.
1952 kmp_int32 __kmpc_omp_task_parts(ident_t *loc_ref, kmp_int32 gtid,
1953                                 kmp_task_t *new_task) {
1954   kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
1955 
1956   KA_TRACE(10, ("__kmpc_omp_task_parts(enter): T#%d loc=%p task=%p\n", gtid,
1957                 loc_ref, new_taskdata));
1958 
1959 #if OMPT_SUPPORT
1960   kmp_taskdata_t *parent;
1961   if (UNLIKELY(ompt_enabled.enabled)) {
1962     parent = new_taskdata->td_parent;
1963     if (ompt_enabled.ompt_callback_task_create) {
1964       ompt_callbacks.ompt_callback(ompt_callback_task_create)(
1965           &(parent->ompt_task_info.task_data), &(parent->ompt_task_info.frame),
1966           &(new_taskdata->ompt_task_info.task_data), ompt_task_explicit, 0,
1967           OMPT_GET_RETURN_ADDRESS(0));
1968     }
1969   }
1970 #endif
1971 
1972   /* Should we execute the new task or queue it? For now, let's just always try
1973      to queue it.  If the queue fills up, then we'll execute it.  */
1974 
1975   if (__kmp_push_task(gtid, new_task) == TASK_NOT_PUSHED) // if cannot defer
1976   { // Execute this task immediately
1977     kmp_taskdata_t *current_task = __kmp_threads[gtid]->th.th_current_task;
1978     new_taskdata->td_flags.task_serial = 1;
1979     __kmp_invoke_task(gtid, new_task, current_task);
1980   }
1981 
1982   KA_TRACE(
1983       10,
1984       ("__kmpc_omp_task_parts(exit): T#%d returning TASK_CURRENT_NOT_QUEUED: "
1985        "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n",
1986        gtid, loc_ref, new_taskdata));
1987 
1988 #if OMPT_SUPPORT
1989   if (UNLIKELY(ompt_enabled.enabled)) {
1990     parent->ompt_task_info.frame.enter_frame = ompt_data_none;
1991   }
1992 #endif
1993   return TASK_CURRENT_NOT_QUEUED;
1994 }
1995 
1996 // __kmp_omp_task: Schedule a non-thread-switchable task for execution
1997 //
1998 // gtid: Global Thread ID of encountering thread
1999 // new_task:non-thread-switchable task thunk allocated by __kmp_omp_task_alloc()
2000 // serialize_immediate: if TRUE then if the task is executed immediately its
2001 // execution will be serialized
2002 // Returns:
2003 //    TASK_CURRENT_NOT_QUEUED (0) if did not suspend and queue current task to
2004 //    be resumed later.
2005 //    TASK_CURRENT_QUEUED (1) if suspended and queued the current task to be
2006 //    resumed later.
2007 kmp_int32 __kmp_omp_task(kmp_int32 gtid, kmp_task_t *new_task,
2008                          bool serialize_immediate) {
2009   kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
2010 
2011 #if OMPX_TASKGRAPH
2012   if (new_taskdata->is_taskgraph &&
2013       __kmp_tdg_is_recording(new_taskdata->tdg->tdg_status)) {
2014     kmp_tdg_info_t *tdg = new_taskdata->tdg;
2015     // extend the record_map if needed
2016     if (new_taskdata->td_task_id >= new_taskdata->tdg->map_size) {
2017       __kmp_acquire_bootstrap_lock(&tdg->graph_lock);
2018       // map_size could have been updated by another thread if recursive
2019       // taskloop
2020       if (new_taskdata->td_task_id >= tdg->map_size) {
2021         kmp_uint old_size = tdg->map_size;
2022         kmp_uint new_size = old_size * 2;
2023         kmp_node_info_t *old_record = tdg->record_map;
2024         kmp_node_info_t *new_record = (kmp_node_info_t *)__kmp_allocate(
2025             new_size * sizeof(kmp_node_info_t));
2026 
2027         KMP_MEMCPY(new_record, old_record, old_size * sizeof(kmp_node_info_t));
2028         tdg->record_map = new_record;
2029 
2030         __kmp_free(old_record);
2031 
2032         for (kmp_int i = old_size; i < new_size; i++) {
2033           kmp_int32 *successorsList = (kmp_int32 *)__kmp_allocate(
2034               __kmp_successors_size * sizeof(kmp_int32));
2035           new_record[i].task = nullptr;
2036           new_record[i].successors = successorsList;
2037           new_record[i].nsuccessors = 0;
2038           new_record[i].npredecessors = 0;
2039           new_record[i].successors_size = __kmp_successors_size;
2040           KMP_ATOMIC_ST_REL(&new_record[i].npredecessors_counter, 0);
2041         }
2042         // update the size at the end, so that we avoid other
2043         // threads use old_record while map_size is already updated
2044         tdg->map_size = new_size;
2045       }
2046       __kmp_release_bootstrap_lock(&tdg->graph_lock);
2047     }
2048     // record a task
2049     if (tdg->record_map[new_taskdata->td_task_id].task == nullptr) {
2050       tdg->record_map[new_taskdata->td_task_id].task = new_task;
2051       tdg->record_map[new_taskdata->td_task_id].parent_task =
2052           new_taskdata->td_parent;
2053       KMP_ATOMIC_INC(&tdg->num_tasks);
2054     }
2055   }
2056 #endif
2057 
2058   /* Should we execute the new task or queue it? For now, let's just always try
2059      to queue it.  If the queue fills up, then we'll execute it.  */
2060   if (new_taskdata->td_flags.proxy == TASK_PROXY ||
2061       __kmp_push_task(gtid, new_task) == TASK_NOT_PUSHED) // if cannot defer
2062   { // Execute this task immediately
2063     kmp_taskdata_t *current_task = __kmp_threads[gtid]->th.th_current_task;
2064     if (serialize_immediate)
2065       new_taskdata->td_flags.task_serial = 1;
2066     __kmp_invoke_task(gtid, new_task, current_task);
2067   } else if (__kmp_dflt_blocktime != KMP_MAX_BLOCKTIME &&
2068              __kmp_wpolicy_passive) {
2069     kmp_info_t *this_thr = __kmp_threads[gtid];
2070     kmp_team_t *team = this_thr->th.th_team;
2071     kmp_int32 nthreads = this_thr->th.th_team_nproc;
2072     for (int i = 0; i < nthreads; ++i) {
2073       kmp_info_t *thread = team->t.t_threads[i];
2074       if (thread == this_thr)
2075         continue;
2076       if (thread->th.th_sleep_loc != NULL) {
2077         __kmp_null_resume_wrapper(thread);
2078         break; // awake one thread at a time
2079       }
2080     }
2081   }
2082   return TASK_CURRENT_NOT_QUEUED;
2083 }
2084 
2085 // __kmpc_omp_task: Wrapper around __kmp_omp_task to schedule a
2086 // non-thread-switchable task from the parent thread only!
2087 //
2088 // loc_ref: location of original task pragma (ignored)
2089 // gtid: Global Thread ID of encountering thread
2090 // new_task: non-thread-switchable task thunk allocated by
2091 // __kmp_omp_task_alloc()
2092 // Returns:
2093 //    TASK_CURRENT_NOT_QUEUED (0) if did not suspend and queue current task to
2094 //    be resumed later.
2095 //    TASK_CURRENT_QUEUED (1) if suspended and queued the current task to be
2096 //    resumed later.
2097 kmp_int32 __kmpc_omp_task(ident_t *loc_ref, kmp_int32 gtid,
2098                           kmp_task_t *new_task) {
2099   kmp_int32 res;
2100   KMP_SET_THREAD_STATE_BLOCK(EXPLICIT_TASK);
2101 
2102 #if KMP_DEBUG || OMPT_SUPPORT
2103   kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
2104 #endif
2105   KA_TRACE(10, ("__kmpc_omp_task(enter): T#%d loc=%p task=%p\n", gtid, loc_ref,
2106                 new_taskdata));
2107   __kmp_assert_valid_gtid(gtid);
2108 
2109 #if OMPT_SUPPORT
2110   kmp_taskdata_t *parent = NULL;
2111   if (UNLIKELY(ompt_enabled.enabled)) {
2112     if (!new_taskdata->td_flags.started) {
2113       OMPT_STORE_RETURN_ADDRESS(gtid);
2114       parent = new_taskdata->td_parent;
2115       if (!parent->ompt_task_info.frame.enter_frame.ptr) {
2116         parent->ompt_task_info.frame.enter_frame.ptr =
2117             OMPT_GET_FRAME_ADDRESS(0);
2118       }
2119       if (ompt_enabled.ompt_callback_task_create) {
2120         ompt_callbacks.ompt_callback(ompt_callback_task_create)(
2121             &(parent->ompt_task_info.task_data),
2122             &(parent->ompt_task_info.frame),
2123             &(new_taskdata->ompt_task_info.task_data),
2124             ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 0,
2125             OMPT_LOAD_RETURN_ADDRESS(gtid));
2126       }
2127     } else {
2128       // We are scheduling the continuation of an UNTIED task.
2129       // Scheduling back to the parent task.
2130       __ompt_task_finish(new_task,
2131                          new_taskdata->ompt_task_info.scheduling_parent,
2132                          ompt_task_switch);
2133       new_taskdata->ompt_task_info.frame.exit_frame = ompt_data_none;
2134     }
2135   }
2136 #endif
2137 
2138   res = __kmp_omp_task(gtid, new_task, true);
2139 
2140   KA_TRACE(10, ("__kmpc_omp_task(exit): T#%d returning "
2141                 "TASK_CURRENT_NOT_QUEUED: loc=%p task=%p\n",
2142                 gtid, loc_ref, new_taskdata));
2143 #if OMPT_SUPPORT
2144   if (UNLIKELY(ompt_enabled.enabled && parent != NULL)) {
2145     parent->ompt_task_info.frame.enter_frame = ompt_data_none;
2146   }
2147 #endif
2148   return res;
2149 }
2150 
2151 // __kmp_omp_taskloop_task: Wrapper around __kmp_omp_task to schedule
2152 // a taskloop task with the correct OMPT return address
2153 //
2154 // loc_ref: location of original task pragma (ignored)
2155 // gtid: Global Thread ID of encountering thread
2156 // new_task: non-thread-switchable task thunk allocated by
2157 // __kmp_omp_task_alloc()
2158 // codeptr_ra: return address for OMPT callback
2159 // Returns:
2160 //    TASK_CURRENT_NOT_QUEUED (0) if did not suspend and queue current task to
2161 //    be resumed later.
2162 //    TASK_CURRENT_QUEUED (1) if suspended and queued the current task to be
2163 //    resumed later.
2164 kmp_int32 __kmp_omp_taskloop_task(ident_t *loc_ref, kmp_int32 gtid,
2165                                   kmp_task_t *new_task, void *codeptr_ra) {
2166   kmp_int32 res;
2167   KMP_SET_THREAD_STATE_BLOCK(EXPLICIT_TASK);
2168 
2169 #if KMP_DEBUG || OMPT_SUPPORT
2170   kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
2171 #endif
2172   KA_TRACE(10, ("__kmpc_omp_task(enter): T#%d loc=%p task=%p\n", gtid, loc_ref,
2173                 new_taskdata));
2174 
2175 #if OMPT_SUPPORT
2176   kmp_taskdata_t *parent = NULL;
2177   if (UNLIKELY(ompt_enabled.enabled && !new_taskdata->td_flags.started)) {
2178     parent = new_taskdata->td_parent;
2179     if (!parent->ompt_task_info.frame.enter_frame.ptr)
2180       parent->ompt_task_info.frame.enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
2181     if (ompt_enabled.ompt_callback_task_create) {
2182       ompt_callbacks.ompt_callback(ompt_callback_task_create)(
2183           &(parent->ompt_task_info.task_data), &(parent->ompt_task_info.frame),
2184           &(new_taskdata->ompt_task_info.task_data),
2185           ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 0,
2186           codeptr_ra);
2187     }
2188   }
2189 #endif
2190 
2191   res = __kmp_omp_task(gtid, new_task, true);
2192 
2193   KA_TRACE(10, ("__kmpc_omp_task(exit): T#%d returning "
2194                 "TASK_CURRENT_NOT_QUEUED: loc=%p task=%p\n",
2195                 gtid, loc_ref, new_taskdata));
2196 #if OMPT_SUPPORT
2197   if (UNLIKELY(ompt_enabled.enabled && parent != NULL)) {
2198     parent->ompt_task_info.frame.enter_frame = ompt_data_none;
2199   }
2200 #endif
2201   return res;
2202 }
2203 
2204 template <bool ompt>
2205 static kmp_int32 __kmpc_omp_taskwait_template(ident_t *loc_ref, kmp_int32 gtid,
2206                                               void *frame_address,
2207                                               void *return_address) {
2208   kmp_taskdata_t *taskdata = nullptr;
2209   kmp_info_t *thread;
2210   int thread_finished = FALSE;
2211   KMP_SET_THREAD_STATE_BLOCK(TASKWAIT);
2212 
2213   KA_TRACE(10, ("__kmpc_omp_taskwait(enter): T#%d loc=%p\n", gtid, loc_ref));
2214   KMP_DEBUG_ASSERT(gtid >= 0);
2215 
2216   if (__kmp_tasking_mode != tskm_immediate_exec) {
2217     thread = __kmp_threads[gtid];
2218     taskdata = thread->th.th_current_task;
2219 
2220 #if OMPT_SUPPORT && OMPT_OPTIONAL
2221     ompt_data_t *my_task_data;
2222     ompt_data_t *my_parallel_data;
2223 
2224     if (ompt) {
2225       my_task_data = &(taskdata->ompt_task_info.task_data);
2226       my_parallel_data = OMPT_CUR_TEAM_DATA(thread);
2227 
2228       taskdata->ompt_task_info.frame.enter_frame.ptr = frame_address;
2229 
2230       if (ompt_enabled.ompt_callback_sync_region) {
2231         ompt_callbacks.ompt_callback(ompt_callback_sync_region)(
2232             ompt_sync_region_taskwait, ompt_scope_begin, my_parallel_data,
2233             my_task_data, return_address);
2234       }
2235 
2236       if (ompt_enabled.ompt_callback_sync_region_wait) {
2237         ompt_callbacks.ompt_callback(ompt_callback_sync_region_wait)(
2238             ompt_sync_region_taskwait, ompt_scope_begin, my_parallel_data,
2239             my_task_data, return_address);
2240       }
2241     }
2242 #endif // OMPT_SUPPORT && OMPT_OPTIONAL
2243 
2244 // Debugger: The taskwait is active. Store location and thread encountered the
2245 // taskwait.
2246 #if USE_ITT_BUILD
2247 // Note: These values are used by ITT events as well.
2248 #endif /* USE_ITT_BUILD */
2249     taskdata->td_taskwait_counter += 1;
2250     taskdata->td_taskwait_ident = loc_ref;
2251     taskdata->td_taskwait_thread = gtid + 1;
2252 
2253 #if USE_ITT_BUILD
2254     void *itt_sync_obj = NULL;
2255 #if USE_ITT_NOTIFY
2256     KMP_ITT_TASKWAIT_STARTING(itt_sync_obj);
2257 #endif /* USE_ITT_NOTIFY */
2258 #endif /* USE_ITT_BUILD */
2259 
2260     bool must_wait =
2261         !taskdata->td_flags.team_serial && !taskdata->td_flags.final;
2262 
2263     must_wait = must_wait || (thread->th.th_task_team != NULL &&
2264                               thread->th.th_task_team->tt.tt_found_proxy_tasks);
2265     // If hidden helper thread is encountered, we must enable wait here.
2266     must_wait =
2267         must_wait ||
2268         (__kmp_enable_hidden_helper && thread->th.th_task_team != NULL &&
2269          thread->th.th_task_team->tt.tt_hidden_helper_task_encountered);
2270 
2271     if (must_wait) {
2272       kmp_flag_32<false, false> flag(
2273           RCAST(std::atomic<kmp_uint32> *,
2274                 &(taskdata->td_incomplete_child_tasks)),
2275           0U);
2276       while (KMP_ATOMIC_LD_ACQ(&taskdata->td_incomplete_child_tasks) != 0) {
2277         flag.execute_tasks(thread, gtid, FALSE,
2278                            &thread_finished USE_ITT_BUILD_ARG(itt_sync_obj),
2279                            __kmp_task_stealing_constraint);
2280       }
2281     }
2282 #if USE_ITT_BUILD
2283     KMP_ITT_TASKWAIT_FINISHED(itt_sync_obj);
2284     KMP_FSYNC_ACQUIRED(taskdata); // acquire self - sync with children
2285 #endif /* USE_ITT_BUILD */
2286 
2287     // Debugger:  The taskwait is completed. Location remains, but thread is
2288     // negated.
2289     taskdata->td_taskwait_thread = -taskdata->td_taskwait_thread;
2290 
2291 #if OMPT_SUPPORT && OMPT_OPTIONAL
2292     if (ompt) {
2293       if (ompt_enabled.ompt_callback_sync_region_wait) {
2294         ompt_callbacks.ompt_callback(ompt_callback_sync_region_wait)(
2295             ompt_sync_region_taskwait, ompt_scope_end, my_parallel_data,
2296             my_task_data, return_address);
2297       }
2298       if (ompt_enabled.ompt_callback_sync_region) {
2299         ompt_callbacks.ompt_callback(ompt_callback_sync_region)(
2300             ompt_sync_region_taskwait, ompt_scope_end, my_parallel_data,
2301             my_task_data, return_address);
2302       }
2303       taskdata->ompt_task_info.frame.enter_frame = ompt_data_none;
2304     }
2305 #endif // OMPT_SUPPORT && OMPT_OPTIONAL
2306   }
2307 
2308   KA_TRACE(10, ("__kmpc_omp_taskwait(exit): T#%d task %p finished waiting, "
2309                 "returning TASK_CURRENT_NOT_QUEUED\n",
2310                 gtid, taskdata));
2311 
2312   return TASK_CURRENT_NOT_QUEUED;
2313 }
2314 
2315 #if OMPT_SUPPORT && OMPT_OPTIONAL
2316 OMPT_NOINLINE
2317 static kmp_int32 __kmpc_omp_taskwait_ompt(ident_t *loc_ref, kmp_int32 gtid,
2318                                           void *frame_address,
2319                                           void *return_address) {
2320   return __kmpc_omp_taskwait_template<true>(loc_ref, gtid, frame_address,
2321                                             return_address);
2322 }
2323 #endif // OMPT_SUPPORT && OMPT_OPTIONAL
2324 
2325 // __kmpc_omp_taskwait: Wait until all tasks generated by the current task are
2326 // complete
2327 kmp_int32 __kmpc_omp_taskwait(ident_t *loc_ref, kmp_int32 gtid) {
2328 #if OMPT_SUPPORT && OMPT_OPTIONAL
2329   if (UNLIKELY(ompt_enabled.enabled)) {
2330     OMPT_STORE_RETURN_ADDRESS(gtid);
2331     return __kmpc_omp_taskwait_ompt(loc_ref, gtid, OMPT_GET_FRAME_ADDRESS(0),
2332                                     OMPT_LOAD_RETURN_ADDRESS(gtid));
2333   }
2334 #endif
2335   return __kmpc_omp_taskwait_template<false>(loc_ref, gtid, NULL, NULL);
2336 }
2337 
2338 // __kmpc_omp_taskyield: switch to a different task
2339 kmp_int32 __kmpc_omp_taskyield(ident_t *loc_ref, kmp_int32 gtid, int end_part) {
2340   kmp_taskdata_t *taskdata = NULL;
2341   kmp_info_t *thread;
2342   int thread_finished = FALSE;
2343 
2344   KMP_COUNT_BLOCK(OMP_TASKYIELD);
2345   KMP_SET_THREAD_STATE_BLOCK(TASKYIELD);
2346 
2347   KA_TRACE(10, ("__kmpc_omp_taskyield(enter): T#%d loc=%p end_part = %d\n",
2348                 gtid, loc_ref, end_part));
2349   __kmp_assert_valid_gtid(gtid);
2350 
2351   if (__kmp_tasking_mode != tskm_immediate_exec && __kmp_init_parallel) {
2352     thread = __kmp_threads[gtid];
2353     taskdata = thread->th.th_current_task;
2354 // Should we model this as a task wait or not?
2355 // Debugger: The taskwait is active. Store location and thread encountered the
2356 // taskwait.
2357 #if USE_ITT_BUILD
2358 // Note: These values are used by ITT events as well.
2359 #endif /* USE_ITT_BUILD */
2360     taskdata->td_taskwait_counter += 1;
2361     taskdata->td_taskwait_ident = loc_ref;
2362     taskdata->td_taskwait_thread = gtid + 1;
2363 
2364 #if USE_ITT_BUILD
2365     void *itt_sync_obj = NULL;
2366 #if USE_ITT_NOTIFY
2367     KMP_ITT_TASKWAIT_STARTING(itt_sync_obj);
2368 #endif /* USE_ITT_NOTIFY */
2369 #endif /* USE_ITT_BUILD */
2370     if (!taskdata->td_flags.team_serial) {
2371       kmp_task_team_t *task_team = thread->th.th_task_team;
2372       if (task_team != NULL) {
2373         if (KMP_TASKING_ENABLED(task_team)) {
2374 #if OMPT_SUPPORT
2375           if (UNLIKELY(ompt_enabled.enabled))
2376             thread->th.ompt_thread_info.ompt_task_yielded = 1;
2377 #endif
2378           __kmp_execute_tasks_32(
2379               thread, gtid, (kmp_flag_32<> *)NULL, FALSE,
2380               &thread_finished USE_ITT_BUILD_ARG(itt_sync_obj),
2381               __kmp_task_stealing_constraint);
2382 #if OMPT_SUPPORT
2383           if (UNLIKELY(ompt_enabled.enabled))
2384             thread->th.ompt_thread_info.ompt_task_yielded = 0;
2385 #endif
2386         }
2387       }
2388     }
2389 #if USE_ITT_BUILD
2390     KMP_ITT_TASKWAIT_FINISHED(itt_sync_obj);
2391 #endif /* USE_ITT_BUILD */
2392 
2393     // Debugger:  The taskwait is completed. Location remains, but thread is
2394     // negated.
2395     taskdata->td_taskwait_thread = -taskdata->td_taskwait_thread;
2396   }
2397 
2398   KA_TRACE(10, ("__kmpc_omp_taskyield(exit): T#%d task %p resuming, "
2399                 "returning TASK_CURRENT_NOT_QUEUED\n",
2400                 gtid, taskdata));
2401 
2402   return TASK_CURRENT_NOT_QUEUED;
2403 }
2404 
2405 // Task Reduction implementation
2406 //
2407 // Note: initial implementation didn't take into account the possibility
2408 // to specify omp_orig for initializer of the UDR (user defined reduction).
2409 // Corrected implementation takes into account the omp_orig object.
2410 // Compiler is free to use old implementation if omp_orig is not specified.
2411 
2412 /*!
2413 @ingroup BASIC_TYPES
2414 @{
2415 */
2416 
2417 /*!
2418 Flags for special info per task reduction item.
2419 */
2420 typedef struct kmp_taskred_flags {
2421   /*! 1 - use lazy alloc/init (e.g. big objects, num tasks < num threads) */
2422   unsigned lazy_priv : 1;
2423   unsigned reserved31 : 31;
2424 } kmp_taskred_flags_t;
2425 
2426 /*!
2427 Internal struct for reduction data item related info set up by compiler.
2428 */
2429 typedef struct kmp_task_red_input {
2430   void *reduce_shar; /**< shared between tasks item to reduce into */
2431   size_t reduce_size; /**< size of data item in bytes */
2432   // three compiler-generated routines (init, fini are optional):
2433   void *reduce_init; /**< data initialization routine (single parameter) */
2434   void *reduce_fini; /**< data finalization routine */
2435   void *reduce_comb; /**< data combiner routine */
2436   kmp_taskred_flags_t flags; /**< flags for additional info from compiler */
2437 } kmp_task_red_input_t;
2438 
2439 /*!
2440 Internal struct for reduction data item related info saved by the library.
2441 */
2442 typedef struct kmp_taskred_data {
2443   void *reduce_shar; /**< shared between tasks item to reduce into */
2444   size_t reduce_size; /**< size of data item */
2445   kmp_taskred_flags_t flags; /**< flags for additional info from compiler */
2446   void *reduce_priv; /**< array of thread specific items */
2447   void *reduce_pend; /**< end of private data for faster comparison op */
2448   // three compiler-generated routines (init, fini are optional):
2449   void *reduce_comb; /**< data combiner routine */
2450   void *reduce_init; /**< data initialization routine (two parameters) */
2451   void *reduce_fini; /**< data finalization routine */
2452   void *reduce_orig; /**< original item (can be used in UDR initializer) */
2453 } kmp_taskred_data_t;
2454 
2455 /*!
2456 Internal struct for reduction data item related info set up by compiler.
2457 
2458 New interface: added reduce_orig field to provide omp_orig for UDR initializer.
2459 */
2460 typedef struct kmp_taskred_input {
2461   void *reduce_shar; /**< shared between tasks item to reduce into */
2462   void *reduce_orig; /**< original reduction item used for initialization */
2463   size_t reduce_size; /**< size of data item */
2464   // three compiler-generated routines (init, fini are optional):
2465   void *reduce_init; /**< data initialization routine (two parameters) */
2466   void *reduce_fini; /**< data finalization routine */
2467   void *reduce_comb; /**< data combiner routine */
2468   kmp_taskred_flags_t flags; /**< flags for additional info from compiler */
2469 } kmp_taskred_input_t;
2470 /*!
2471 @}
2472 */
2473 
2474 template <typename T> void __kmp_assign_orig(kmp_taskred_data_t &item, T &src);
2475 template <>
2476 void __kmp_assign_orig<kmp_task_red_input_t>(kmp_taskred_data_t &item,
2477                                              kmp_task_red_input_t &src) {
2478   item.reduce_orig = NULL;
2479 }
2480 template <>
2481 void __kmp_assign_orig<kmp_taskred_input_t>(kmp_taskred_data_t &item,
2482                                             kmp_taskred_input_t &src) {
2483   if (src.reduce_orig != NULL) {
2484     item.reduce_orig = src.reduce_orig;
2485   } else {
2486     item.reduce_orig = src.reduce_shar;
2487   } // non-NULL reduce_orig means new interface used
2488 }
2489 
2490 template <typename T> void __kmp_call_init(kmp_taskred_data_t &item, size_t j);
2491 template <>
2492 void __kmp_call_init<kmp_task_red_input_t>(kmp_taskred_data_t &item,
2493                                            size_t offset) {
2494   ((void (*)(void *))item.reduce_init)((char *)(item.reduce_priv) + offset);
2495 }
2496 template <>
2497 void __kmp_call_init<kmp_taskred_input_t>(kmp_taskred_data_t &item,
2498                                           size_t offset) {
2499   ((void (*)(void *, void *))item.reduce_init)(
2500       (char *)(item.reduce_priv) + offset, item.reduce_orig);
2501 }
2502 
2503 template <typename T>
2504 void *__kmp_task_reduction_init(int gtid, int num, T *data) {
2505   __kmp_assert_valid_gtid(gtid);
2506   kmp_info_t *thread = __kmp_threads[gtid];
2507   kmp_taskgroup_t *tg = thread->th.th_current_task->td_taskgroup;
2508   kmp_uint32 nth = thread->th.th_team_nproc;
2509   kmp_taskred_data_t *arr;
2510 
2511   // check input data just in case
2512   KMP_ASSERT(tg != NULL);
2513   KMP_ASSERT(data != NULL);
2514   KMP_ASSERT(num > 0);
2515   if (nth == 1) {
2516     KA_TRACE(10, ("__kmpc_task_reduction_init: T#%d, tg %p, exiting nth=1\n",
2517                   gtid, tg));
2518     return (void *)tg;
2519   }
2520   KA_TRACE(10, ("__kmpc_task_reduction_init: T#%d, taskgroup %p, #items %d\n",
2521                 gtid, tg, num));
2522   arr = (kmp_taskred_data_t *)__kmp_thread_malloc(
2523       thread, num * sizeof(kmp_taskred_data_t));
2524   for (int i = 0; i < num; ++i) {
2525     size_t size = data[i].reduce_size - 1;
2526     // round the size up to cache line per thread-specific item
2527     size += CACHE_LINE - size % CACHE_LINE;
2528     KMP_ASSERT(data[i].reduce_comb != NULL); // combiner is mandatory
2529     arr[i].reduce_shar = data[i].reduce_shar;
2530     arr[i].reduce_size = size;
2531     arr[i].flags = data[i].flags;
2532     arr[i].reduce_comb = data[i].reduce_comb;
2533     arr[i].reduce_init = data[i].reduce_init;
2534     arr[i].reduce_fini = data[i].reduce_fini;
2535     __kmp_assign_orig<T>(arr[i], data[i]);
2536     if (!arr[i].flags.lazy_priv) {
2537       // allocate cache-line aligned block and fill it with zeros
2538       arr[i].reduce_priv = __kmp_allocate(nth * size);
2539       arr[i].reduce_pend = (char *)(arr[i].reduce_priv) + nth * size;
2540       if (arr[i].reduce_init != NULL) {
2541         // initialize all thread-specific items
2542         for (size_t j = 0; j < nth; ++j) {
2543           __kmp_call_init<T>(arr[i], j * size);
2544         }
2545       }
2546     } else {
2547       // only allocate space for pointers now,
2548       // objects will be lazily allocated/initialized if/when requested
2549       // note that __kmp_allocate zeroes the allocated memory
2550       arr[i].reduce_priv = __kmp_allocate(nth * sizeof(void *));
2551     }
2552   }
2553   tg->reduce_data = (void *)arr;
2554   tg->reduce_num_data = num;
2555   return (void *)tg;
2556 }
2557 
2558 /*!
2559 @ingroup TASKING
2560 @param gtid      Global thread ID
2561 @param num       Number of data items to reduce
2562 @param data      Array of data for reduction
2563 @return The taskgroup identifier
2564 
2565 Initialize task reduction for the taskgroup.
2566 
2567 Note: this entry supposes the optional compiler-generated initializer routine
2568 has single parameter - pointer to object to be initialized. That means
2569 the reduction either does not use omp_orig object, or the omp_orig is accessible
2570 without help of the runtime library.
2571 */
2572 void *__kmpc_task_reduction_init(int gtid, int num, void *data) {
2573 #if OMPX_TASKGRAPH
2574   kmp_tdg_info_t *tdg = __kmp_find_tdg(__kmp_curr_tdg_idx);
2575   if (tdg && __kmp_tdg_is_recording(tdg->tdg_status)) {
2576     kmp_tdg_info_t *this_tdg = __kmp_global_tdgs[__kmp_curr_tdg_idx];
2577     this_tdg->rec_taskred_data =
2578         __kmp_allocate(sizeof(kmp_task_red_input_t) * num);
2579     this_tdg->rec_num_taskred = num;
2580     KMP_MEMCPY(this_tdg->rec_taskred_data, data,
2581                sizeof(kmp_task_red_input_t) * num);
2582   }
2583 #endif
2584   return __kmp_task_reduction_init(gtid, num, (kmp_task_red_input_t *)data);
2585 }
2586 
2587 /*!
2588 @ingroup TASKING
2589 @param gtid      Global thread ID
2590 @param num       Number of data items to reduce
2591 @param data      Array of data for reduction
2592 @return The taskgroup identifier
2593 
2594 Initialize task reduction for the taskgroup.
2595 
2596 Note: this entry supposes the optional compiler-generated initializer routine
2597 has two parameters, pointer to object to be initialized and pointer to omp_orig
2598 */
2599 void *__kmpc_taskred_init(int gtid, int num, void *data) {
2600 #if OMPX_TASKGRAPH
2601   kmp_tdg_info_t *tdg = __kmp_find_tdg(__kmp_curr_tdg_idx);
2602   if (tdg && __kmp_tdg_is_recording(tdg->tdg_status)) {
2603     kmp_tdg_info_t *this_tdg = __kmp_global_tdgs[__kmp_curr_tdg_idx];
2604     this_tdg->rec_taskred_data =
2605         __kmp_allocate(sizeof(kmp_task_red_input_t) * num);
2606     this_tdg->rec_num_taskred = num;
2607     KMP_MEMCPY(this_tdg->rec_taskred_data, data,
2608                sizeof(kmp_task_red_input_t) * num);
2609   }
2610 #endif
2611   return __kmp_task_reduction_init(gtid, num, (kmp_taskred_input_t *)data);
2612 }
2613 
2614 // Copy task reduction data (except for shared pointers).
2615 template <typename T>
2616 void __kmp_task_reduction_init_copy(kmp_info_t *thr, int num, T *data,
2617                                     kmp_taskgroup_t *tg, void *reduce_data) {
2618   kmp_taskred_data_t *arr;
2619   KA_TRACE(20, ("__kmp_task_reduction_init_copy: Th %p, init taskgroup %p,"
2620                 " from data %p\n",
2621                 thr, tg, reduce_data));
2622   arr = (kmp_taskred_data_t *)__kmp_thread_malloc(
2623       thr, num * sizeof(kmp_taskred_data_t));
2624   // threads will share private copies, thunk routines, sizes, flags, etc.:
2625   KMP_MEMCPY(arr, reduce_data, num * sizeof(kmp_taskred_data_t));
2626   for (int i = 0; i < num; ++i) {
2627     arr[i].reduce_shar = data[i].reduce_shar; // init unique shared pointers
2628   }
2629   tg->reduce_data = (void *)arr;
2630   tg->reduce_num_data = num;
2631 }
2632 
2633 /*!
2634 @ingroup TASKING
2635 @param gtid    Global thread ID
2636 @param tskgrp  The taskgroup ID (optional)
2637 @param data    Shared location of the item
2638 @return The pointer to per-thread data
2639 
2640 Get thread-specific location of data item
2641 */
2642 void *__kmpc_task_reduction_get_th_data(int gtid, void *tskgrp, void *data) {
2643   __kmp_assert_valid_gtid(gtid);
2644   kmp_info_t *thread = __kmp_threads[gtid];
2645   kmp_int32 nth = thread->th.th_team_nproc;
2646   if (nth == 1)
2647     return data; // nothing to do
2648 
2649   kmp_taskgroup_t *tg = (kmp_taskgroup_t *)tskgrp;
2650   if (tg == NULL)
2651     tg = thread->th.th_current_task->td_taskgroup;
2652   KMP_ASSERT(tg != NULL);
2653   kmp_taskred_data_t *arr = (kmp_taskred_data_t *)(tg->reduce_data);
2654   kmp_int32 num = tg->reduce_num_data;
2655   kmp_int32 tid = thread->th.th_info.ds.ds_tid;
2656 
2657 #if OMPX_TASKGRAPH
2658   if ((thread->th.th_current_task->is_taskgraph) &&
2659       (!__kmp_tdg_is_recording(
2660           __kmp_global_tdgs[__kmp_curr_tdg_idx]->tdg_status))) {
2661     tg = thread->th.th_current_task->td_taskgroup;
2662     KMP_ASSERT(tg != NULL);
2663     KMP_ASSERT(tg->reduce_data != NULL);
2664     arr = (kmp_taskred_data_t *)(tg->reduce_data);
2665     num = tg->reduce_num_data;
2666   }
2667 #endif
2668 
2669   KMP_ASSERT(data != NULL);
2670   while (tg != NULL) {
2671     for (int i = 0; i < num; ++i) {
2672       if (!arr[i].flags.lazy_priv) {
2673         if (data == arr[i].reduce_shar ||
2674             (data >= arr[i].reduce_priv && data < arr[i].reduce_pend))
2675           return (char *)(arr[i].reduce_priv) + tid * arr[i].reduce_size;
2676       } else {
2677         // check shared location first
2678         void **p_priv = (void **)(arr[i].reduce_priv);
2679         if (data == arr[i].reduce_shar)
2680           goto found;
2681         // check if we get some thread specific location as parameter
2682         for (int j = 0; j < nth; ++j)
2683           if (data == p_priv[j])
2684             goto found;
2685         continue; // not found, continue search
2686       found:
2687         if (p_priv[tid] == NULL) {
2688           // allocate thread specific object lazily
2689           p_priv[tid] = __kmp_allocate(arr[i].reduce_size);
2690           if (arr[i].reduce_init != NULL) {
2691             if (arr[i].reduce_orig != NULL) { // new interface
2692               ((void (*)(void *, void *))arr[i].reduce_init)(
2693                   p_priv[tid], arr[i].reduce_orig);
2694             } else { // old interface (single parameter)
2695               ((void (*)(void *))arr[i].reduce_init)(p_priv[tid]);
2696             }
2697           }
2698         }
2699         return p_priv[tid];
2700       }
2701     }
2702     tg = tg->parent;
2703     arr = (kmp_taskred_data_t *)(tg->reduce_data);
2704     num = tg->reduce_num_data;
2705   }
2706   KMP_ASSERT2(0, "Unknown task reduction item");
2707   return NULL; // ERROR, this line never executed
2708 }
2709 
2710 // Finalize task reduction.
2711 // Called from __kmpc_end_taskgroup()
2712 static void __kmp_task_reduction_fini(kmp_info_t *th, kmp_taskgroup_t *tg) {
2713   kmp_int32 nth = th->th.th_team_nproc;
2714   KMP_DEBUG_ASSERT(nth > 1); // should not be called if nth == 1
2715   kmp_taskred_data_t *arr = (kmp_taskred_data_t *)tg->reduce_data;
2716   kmp_int32 num = tg->reduce_num_data;
2717   for (int i = 0; i < num; ++i) {
2718     void *sh_data = arr[i].reduce_shar;
2719     void (*f_fini)(void *) = (void (*)(void *))(arr[i].reduce_fini);
2720     void (*f_comb)(void *, void *) =
2721         (void (*)(void *, void *))(arr[i].reduce_comb);
2722     if (!arr[i].flags.lazy_priv) {
2723       void *pr_data = arr[i].reduce_priv;
2724       size_t size = arr[i].reduce_size;
2725       for (int j = 0; j < nth; ++j) {
2726         void *priv_data = (char *)pr_data + j * size;
2727         f_comb(sh_data, priv_data); // combine results
2728         if (f_fini)
2729           f_fini(priv_data); // finalize if needed
2730       }
2731     } else {
2732       void **pr_data = (void **)(arr[i].reduce_priv);
2733       for (int j = 0; j < nth; ++j) {
2734         if (pr_data[j] != NULL) {
2735           f_comb(sh_data, pr_data[j]); // combine results
2736           if (f_fini)
2737             f_fini(pr_data[j]); // finalize if needed
2738           __kmp_free(pr_data[j]);
2739         }
2740       }
2741     }
2742     __kmp_free(arr[i].reduce_priv);
2743   }
2744   __kmp_thread_free(th, arr);
2745   tg->reduce_data = NULL;
2746   tg->reduce_num_data = 0;
2747 }
2748 
2749 // Cleanup task reduction data for parallel or worksharing,
2750 // do not touch task private data other threads still working with.
2751 // Called from __kmpc_end_taskgroup()
2752 static void __kmp_task_reduction_clean(kmp_info_t *th, kmp_taskgroup_t *tg) {
2753   __kmp_thread_free(th, tg->reduce_data);
2754   tg->reduce_data = NULL;
2755   tg->reduce_num_data = 0;
2756 }
2757 
2758 template <typename T>
2759 void *__kmp_task_reduction_modifier_init(ident_t *loc, int gtid, int is_ws,
2760                                          int num, T *data) {
2761   __kmp_assert_valid_gtid(gtid);
2762   kmp_info_t *thr = __kmp_threads[gtid];
2763   kmp_int32 nth = thr->th.th_team_nproc;
2764   __kmpc_taskgroup(loc, gtid); // form new taskgroup first
2765   if (nth == 1) {
2766     KA_TRACE(10,
2767              ("__kmpc_reduction_modifier_init: T#%d, tg %p, exiting nth=1\n",
2768               gtid, thr->th.th_current_task->td_taskgroup));
2769     return (void *)thr->th.th_current_task->td_taskgroup;
2770   }
2771   kmp_team_t *team = thr->th.th_team;
2772   void *reduce_data;
2773   kmp_taskgroup_t *tg;
2774   reduce_data = KMP_ATOMIC_LD_RLX(&team->t.t_tg_reduce_data[is_ws]);
2775   if (reduce_data == NULL &&
2776       __kmp_atomic_compare_store(&team->t.t_tg_reduce_data[is_ws], reduce_data,
2777                                  (void *)1)) {
2778     // single thread enters this block to initialize common reduction data
2779     KMP_DEBUG_ASSERT(reduce_data == NULL);
2780     // first initialize own data, then make a copy other threads can use
2781     tg = (kmp_taskgroup_t *)__kmp_task_reduction_init<T>(gtid, num, data);
2782     reduce_data = __kmp_thread_malloc(thr, num * sizeof(kmp_taskred_data_t));
2783     KMP_MEMCPY(reduce_data, tg->reduce_data, num * sizeof(kmp_taskred_data_t));
2784     // fini counters should be 0 at this point
2785     KMP_DEBUG_ASSERT(KMP_ATOMIC_LD_RLX(&team->t.t_tg_fini_counter[0]) == 0);
2786     KMP_DEBUG_ASSERT(KMP_ATOMIC_LD_RLX(&team->t.t_tg_fini_counter[1]) == 0);
2787     KMP_ATOMIC_ST_REL(&team->t.t_tg_reduce_data[is_ws], reduce_data);
2788   } else {
2789     while (
2790         (reduce_data = KMP_ATOMIC_LD_ACQ(&team->t.t_tg_reduce_data[is_ws])) ==
2791         (void *)1) { // wait for task reduction initialization
2792       KMP_CPU_PAUSE();
2793     }
2794     KMP_DEBUG_ASSERT(reduce_data > (void *)1); // should be valid pointer here
2795     tg = thr->th.th_current_task->td_taskgroup;
2796     __kmp_task_reduction_init_copy<T>(thr, num, data, tg, reduce_data);
2797   }
2798   return tg;
2799 }
2800 
2801 /*!
2802 @ingroup TASKING
2803 @param loc       Source location info
2804 @param gtid      Global thread ID
2805 @param is_ws     Is 1 if the reduction is for worksharing, 0 otherwise
2806 @param num       Number of data items to reduce
2807 @param data      Array of data for reduction
2808 @return The taskgroup identifier
2809 
2810 Initialize task reduction for a parallel or worksharing.
2811 
2812 Note: this entry supposes the optional compiler-generated initializer routine
2813 has single parameter - pointer to object to be initialized. That means
2814 the reduction either does not use omp_orig object, or the omp_orig is accessible
2815 without help of the runtime library.
2816 */
2817 void *__kmpc_task_reduction_modifier_init(ident_t *loc, int gtid, int is_ws,
2818                                           int num, void *data) {
2819   return __kmp_task_reduction_modifier_init(loc, gtid, is_ws, num,
2820                                             (kmp_task_red_input_t *)data);
2821 }
2822 
2823 /*!
2824 @ingroup TASKING
2825 @param loc       Source location info
2826 @param gtid      Global thread ID
2827 @param is_ws     Is 1 if the reduction is for worksharing, 0 otherwise
2828 @param num       Number of data items to reduce
2829 @param data      Array of data for reduction
2830 @return The taskgroup identifier
2831 
2832 Initialize task reduction for a parallel or worksharing.
2833 
2834 Note: this entry supposes the optional compiler-generated initializer routine
2835 has two parameters, pointer to object to be initialized and pointer to omp_orig
2836 */
2837 void *__kmpc_taskred_modifier_init(ident_t *loc, int gtid, int is_ws, int num,
2838                                    void *data) {
2839   return __kmp_task_reduction_modifier_init(loc, gtid, is_ws, num,
2840                                             (kmp_taskred_input_t *)data);
2841 }
2842 
2843 /*!
2844 @ingroup TASKING
2845 @param loc       Source location info
2846 @param gtid      Global thread ID
2847 @param is_ws     Is 1 if the reduction is for worksharing, 0 otherwise
2848 
2849 Finalize task reduction for a parallel or worksharing.
2850 */
2851 void __kmpc_task_reduction_modifier_fini(ident_t *loc, int gtid, int is_ws) {
2852   __kmpc_end_taskgroup(loc, gtid);
2853 }
2854 
2855 // __kmpc_taskgroup: Start a new taskgroup
2856 void __kmpc_taskgroup(ident_t *loc, int gtid) {
2857   __kmp_assert_valid_gtid(gtid);
2858   kmp_info_t *thread = __kmp_threads[gtid];
2859   kmp_taskdata_t *taskdata = thread->th.th_current_task;
2860   kmp_taskgroup_t *tg_new =
2861       (kmp_taskgroup_t *)__kmp_thread_malloc(thread, sizeof(kmp_taskgroup_t));
2862   KA_TRACE(10, ("__kmpc_taskgroup: T#%d loc=%p group=%p\n", gtid, loc, tg_new));
2863   KMP_ATOMIC_ST_RLX(&tg_new->count, 0);
2864   KMP_ATOMIC_ST_RLX(&tg_new->cancel_request, cancel_noreq);
2865   tg_new->parent = taskdata->td_taskgroup;
2866   tg_new->reduce_data = NULL;
2867   tg_new->reduce_num_data = 0;
2868   tg_new->gomp_data = NULL;
2869   taskdata->td_taskgroup = tg_new;
2870 
2871 #if OMPT_SUPPORT && OMPT_OPTIONAL
2872   if (UNLIKELY(ompt_enabled.ompt_callback_sync_region)) {
2873     void *codeptr = OMPT_LOAD_RETURN_ADDRESS(gtid);
2874     if (!codeptr)
2875       codeptr = OMPT_GET_RETURN_ADDRESS(0);
2876     kmp_team_t *team = thread->th.th_team;
2877     ompt_data_t my_task_data = taskdata->ompt_task_info.task_data;
2878     // FIXME: I think this is wrong for lwt!
2879     ompt_data_t my_parallel_data = team->t.ompt_team_info.parallel_data;
2880 
2881     ompt_callbacks.ompt_callback(ompt_callback_sync_region)(
2882         ompt_sync_region_taskgroup, ompt_scope_begin, &(my_parallel_data),
2883         &(my_task_data), codeptr);
2884   }
2885 #endif
2886 }
2887 
2888 // __kmpc_end_taskgroup: Wait until all tasks generated by the current task
2889 //                       and its descendants are complete
2890 void __kmpc_end_taskgroup(ident_t *loc, int gtid) {
2891   __kmp_assert_valid_gtid(gtid);
2892   kmp_info_t *thread = __kmp_threads[gtid];
2893   kmp_taskdata_t *taskdata = thread->th.th_current_task;
2894   kmp_taskgroup_t *taskgroup = taskdata->td_taskgroup;
2895   int thread_finished = FALSE;
2896 
2897 #if OMPT_SUPPORT && OMPT_OPTIONAL
2898   kmp_team_t *team;
2899   ompt_data_t my_task_data;
2900   ompt_data_t my_parallel_data;
2901   void *codeptr = nullptr;
2902   if (UNLIKELY(ompt_enabled.enabled)) {
2903     team = thread->th.th_team;
2904     my_task_data = taskdata->ompt_task_info.task_data;
2905     // FIXME: I think this is wrong for lwt!
2906     my_parallel_data = team->t.ompt_team_info.parallel_data;
2907     codeptr = OMPT_LOAD_RETURN_ADDRESS(gtid);
2908     if (!codeptr)
2909       codeptr = OMPT_GET_RETURN_ADDRESS(0);
2910   }
2911 #endif
2912 
2913   KA_TRACE(10, ("__kmpc_end_taskgroup(enter): T#%d loc=%p\n", gtid, loc));
2914   KMP_DEBUG_ASSERT(taskgroup != NULL);
2915   KMP_SET_THREAD_STATE_BLOCK(TASKGROUP);
2916 
2917   if (__kmp_tasking_mode != tskm_immediate_exec) {
2918     // mark task as waiting not on a barrier
2919     taskdata->td_taskwait_counter += 1;
2920     taskdata->td_taskwait_ident = loc;
2921     taskdata->td_taskwait_thread = gtid + 1;
2922 #if USE_ITT_BUILD
2923     // For ITT the taskgroup wait is similar to taskwait until we need to
2924     // distinguish them
2925     void *itt_sync_obj = NULL;
2926 #if USE_ITT_NOTIFY
2927     KMP_ITT_TASKWAIT_STARTING(itt_sync_obj);
2928 #endif /* USE_ITT_NOTIFY */
2929 #endif /* USE_ITT_BUILD */
2930 
2931 #if OMPT_SUPPORT && OMPT_OPTIONAL
2932     if (UNLIKELY(ompt_enabled.ompt_callback_sync_region_wait)) {
2933       ompt_callbacks.ompt_callback(ompt_callback_sync_region_wait)(
2934           ompt_sync_region_taskgroup, ompt_scope_begin, &(my_parallel_data),
2935           &(my_task_data), codeptr);
2936     }
2937 #endif
2938 
2939     if (!taskdata->td_flags.team_serial ||
2940         (thread->th.th_task_team != NULL &&
2941          (thread->th.th_task_team->tt.tt_found_proxy_tasks ||
2942           thread->th.th_task_team->tt.tt_hidden_helper_task_encountered))) {
2943       kmp_flag_32<false, false> flag(
2944           RCAST(std::atomic<kmp_uint32> *, &(taskgroup->count)), 0U);
2945       while (KMP_ATOMIC_LD_ACQ(&taskgroup->count) != 0) {
2946         flag.execute_tasks(thread, gtid, FALSE,
2947                            &thread_finished USE_ITT_BUILD_ARG(itt_sync_obj),
2948                            __kmp_task_stealing_constraint);
2949       }
2950     }
2951     taskdata->td_taskwait_thread = -taskdata->td_taskwait_thread; // end waiting
2952 
2953 #if OMPT_SUPPORT && OMPT_OPTIONAL
2954     if (UNLIKELY(ompt_enabled.ompt_callback_sync_region_wait)) {
2955       ompt_callbacks.ompt_callback(ompt_callback_sync_region_wait)(
2956           ompt_sync_region_taskgroup, ompt_scope_end, &(my_parallel_data),
2957           &(my_task_data), codeptr);
2958     }
2959 #endif
2960 
2961 #if USE_ITT_BUILD
2962     KMP_ITT_TASKWAIT_FINISHED(itt_sync_obj);
2963     KMP_FSYNC_ACQUIRED(taskdata); // acquire self - sync with descendants
2964 #endif /* USE_ITT_BUILD */
2965   }
2966   KMP_DEBUG_ASSERT(taskgroup->count == 0);
2967 
2968   if (taskgroup->reduce_data != NULL &&
2969       !taskgroup->gomp_data) { // need to reduce?
2970     int cnt;
2971     void *reduce_data;
2972     kmp_team_t *t = thread->th.th_team;
2973     kmp_taskred_data_t *arr = (kmp_taskred_data_t *)taskgroup->reduce_data;
2974     // check if <priv> data of the first reduction variable shared for the team
2975     void *priv0 = arr[0].reduce_priv;
2976     if ((reduce_data = KMP_ATOMIC_LD_ACQ(&t->t.t_tg_reduce_data[0])) != NULL &&
2977         ((kmp_taskred_data_t *)reduce_data)[0].reduce_priv == priv0) {
2978       // finishing task reduction on parallel
2979       cnt = KMP_ATOMIC_INC(&t->t.t_tg_fini_counter[0]);
2980       if (cnt == thread->th.th_team_nproc - 1) {
2981         // we are the last thread passing __kmpc_reduction_modifier_fini()
2982         // finalize task reduction:
2983         __kmp_task_reduction_fini(thread, taskgroup);
2984         // cleanup fields in the team structure:
2985         // TODO: is relaxed store enough here (whole barrier should follow)?
2986         __kmp_thread_free(thread, reduce_data);
2987         KMP_ATOMIC_ST_REL(&t->t.t_tg_reduce_data[0], NULL);
2988         KMP_ATOMIC_ST_REL(&t->t.t_tg_fini_counter[0], 0);
2989       } else {
2990         // we are not the last thread passing __kmpc_reduction_modifier_fini(),
2991         // so do not finalize reduction, just clean own copy of the data
2992         __kmp_task_reduction_clean(thread, taskgroup);
2993       }
2994     } else if ((reduce_data = KMP_ATOMIC_LD_ACQ(&t->t.t_tg_reduce_data[1])) !=
2995                    NULL &&
2996                ((kmp_taskred_data_t *)reduce_data)[0].reduce_priv == priv0) {
2997       // finishing task reduction on worksharing
2998       cnt = KMP_ATOMIC_INC(&t->t.t_tg_fini_counter[1]);
2999       if (cnt == thread->th.th_team_nproc - 1) {
3000         // we are the last thread passing __kmpc_reduction_modifier_fini()
3001         __kmp_task_reduction_fini(thread, taskgroup);
3002         // cleanup fields in team structure:
3003         // TODO: is relaxed store enough here (whole barrier should follow)?
3004         __kmp_thread_free(thread, reduce_data);
3005         KMP_ATOMIC_ST_REL(&t->t.t_tg_reduce_data[1], NULL);
3006         KMP_ATOMIC_ST_REL(&t->t.t_tg_fini_counter[1], 0);
3007       } else {
3008         // we are not the last thread passing __kmpc_reduction_modifier_fini(),
3009         // so do not finalize reduction, just clean own copy of the data
3010         __kmp_task_reduction_clean(thread, taskgroup);
3011       }
3012     } else {
3013       // finishing task reduction on taskgroup
3014       __kmp_task_reduction_fini(thread, taskgroup);
3015     }
3016   }
3017   // Restore parent taskgroup for the current task
3018   taskdata->td_taskgroup = taskgroup->parent;
3019   __kmp_thread_free(thread, taskgroup);
3020 
3021   KA_TRACE(10, ("__kmpc_end_taskgroup(exit): T#%d task %p finished waiting\n",
3022                 gtid, taskdata));
3023 
3024 #if OMPT_SUPPORT && OMPT_OPTIONAL
3025   if (UNLIKELY(ompt_enabled.ompt_callback_sync_region)) {
3026     ompt_callbacks.ompt_callback(ompt_callback_sync_region)(
3027         ompt_sync_region_taskgroup, ompt_scope_end, &(my_parallel_data),
3028         &(my_task_data), codeptr);
3029   }
3030 #endif
3031 }
3032 
3033 static kmp_task_t *__kmp_get_priority_task(kmp_int32 gtid,
3034                                            kmp_task_team_t *task_team,
3035                                            kmp_int32 is_constrained) {
3036   kmp_task_t *task = NULL;
3037   kmp_taskdata_t *taskdata;
3038   kmp_taskdata_t *current;
3039   kmp_thread_data_t *thread_data;
3040   int ntasks = task_team->tt.tt_num_task_pri;
3041   if (ntasks == 0) {
3042     KA_TRACE(
3043         20, ("__kmp_get_priority_task(exit #1): T#%d No tasks to get\n", gtid));
3044     return NULL;
3045   }
3046   do {
3047     // decrement num_tasks to "reserve" one task to get for execution
3048     if (__kmp_atomic_compare_store(&task_team->tt.tt_num_task_pri, ntasks,
3049                                    ntasks - 1))
3050       break;
3051     ntasks = task_team->tt.tt_num_task_pri;
3052   } while (ntasks > 0);
3053   if (ntasks == 0) {
3054     KA_TRACE(20, ("__kmp_get_priority_task(exit #2): T#%d No tasks to get\n",
3055                   __kmp_get_gtid()));
3056     return NULL;
3057   }
3058   // We got a "ticket" to get a "reserved" priority task
3059   int deque_ntasks;
3060   kmp_task_pri_t *list = task_team->tt.tt_task_pri_list;
3061   do {
3062     KMP_ASSERT(list != NULL);
3063     thread_data = &list->td;
3064     __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
3065     deque_ntasks = thread_data->td.td_deque_ntasks;
3066     if (deque_ntasks == 0) {
3067       __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3068       KA_TRACE(20, ("__kmp_get_priority_task: T#%d No tasks to get from %p\n",
3069                     __kmp_get_gtid(), thread_data));
3070       list = list->next;
3071     }
3072   } while (deque_ntasks == 0);
3073   KMP_DEBUG_ASSERT(deque_ntasks);
3074   int target = thread_data->td.td_deque_head;
3075   current = __kmp_threads[gtid]->th.th_current_task;
3076   taskdata = thread_data->td.td_deque[target];
3077   if (__kmp_task_is_allowed(gtid, is_constrained, taskdata, current)) {
3078     // Bump head pointer and Wrap.
3079     thread_data->td.td_deque_head =
3080         (target + 1) & TASK_DEQUE_MASK(thread_data->td);
3081   } else {
3082     if (!task_team->tt.tt_untied_task_encountered) {
3083       // The TSC does not allow to steal victim task
3084       __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3085       KA_TRACE(20, ("__kmp_get_priority_task(exit #3): T#%d could not get task "
3086                     "from %p: task_team=%p ntasks=%d head=%u tail=%u\n",
3087                     gtid, thread_data, task_team, deque_ntasks, target,
3088                     thread_data->td.td_deque_tail));
3089       task_team->tt.tt_num_task_pri++; // atomic inc, restore value
3090       return NULL;
3091     }
3092     int i;
3093     // walk through the deque trying to steal any task
3094     taskdata = NULL;
3095     for (i = 1; i < deque_ntasks; ++i) {
3096       target = (target + 1) & TASK_DEQUE_MASK(thread_data->td);
3097       taskdata = thread_data->td.td_deque[target];
3098       if (__kmp_task_is_allowed(gtid, is_constrained, taskdata, current)) {
3099         break; // found task to execute
3100       } else {
3101         taskdata = NULL;
3102       }
3103     }
3104     if (taskdata == NULL) {
3105       // No appropriate candidate found to execute
3106       __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3107       KA_TRACE(
3108           10, ("__kmp_get_priority_task(exit #4): T#%d could not get task from "
3109                "%p: task_team=%p ntasks=%d head=%u tail=%u\n",
3110                gtid, thread_data, task_team, deque_ntasks,
3111                thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
3112       task_team->tt.tt_num_task_pri++; // atomic inc, restore value
3113       return NULL;
3114     }
3115     int prev = target;
3116     for (i = i + 1; i < deque_ntasks; ++i) {
3117       // shift remaining tasks in the deque left by 1
3118       target = (target + 1) & TASK_DEQUE_MASK(thread_data->td);
3119       thread_data->td.td_deque[prev] = thread_data->td.td_deque[target];
3120       prev = target;
3121     }
3122     KMP_DEBUG_ASSERT(
3123         thread_data->td.td_deque_tail ==
3124         (kmp_uint32)((target + 1) & TASK_DEQUE_MASK(thread_data->td)));
3125     thread_data->td.td_deque_tail = target; // tail -= 1 (wrapped))
3126   }
3127   thread_data->td.td_deque_ntasks = deque_ntasks - 1;
3128   __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3129   task = KMP_TASKDATA_TO_TASK(taskdata);
3130   return task;
3131 }
3132 
3133 // __kmp_remove_my_task: remove a task from my own deque
3134 static kmp_task_t *__kmp_remove_my_task(kmp_info_t *thread, kmp_int32 gtid,
3135                                         kmp_task_team_t *task_team,
3136                                         kmp_int32 is_constrained) {
3137   kmp_task_t *task;
3138   kmp_taskdata_t *taskdata;
3139   kmp_thread_data_t *thread_data;
3140   kmp_uint32 tail;
3141 
3142   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
3143   KMP_DEBUG_ASSERT(task_team->tt.tt_threads_data !=
3144                    NULL); // Caller should check this condition
3145 
3146   thread_data = &task_team->tt.tt_threads_data[__kmp_tid_from_gtid(gtid)];
3147 
3148   KA_TRACE(10, ("__kmp_remove_my_task(enter): T#%d ntasks=%d head=%u tail=%u\n",
3149                 gtid, thread_data->td.td_deque_ntasks,
3150                 thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
3151 
3152   if (TCR_4(thread_data->td.td_deque_ntasks) == 0) {
3153     KA_TRACE(10,
3154              ("__kmp_remove_my_task(exit #1): T#%d No tasks to remove: "
3155               "ntasks=%d head=%u tail=%u\n",
3156               gtid, thread_data->td.td_deque_ntasks,
3157               thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
3158     return NULL;
3159   }
3160 
3161   __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
3162 
3163   if (TCR_4(thread_data->td.td_deque_ntasks) == 0) {
3164     __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3165     KA_TRACE(10,
3166              ("__kmp_remove_my_task(exit #2): T#%d No tasks to remove: "
3167               "ntasks=%d head=%u tail=%u\n",
3168               gtid, thread_data->td.td_deque_ntasks,
3169               thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
3170     return NULL;
3171   }
3172 
3173   tail = (thread_data->td.td_deque_tail - 1) &
3174          TASK_DEQUE_MASK(thread_data->td); // Wrap index.
3175   taskdata = thread_data->td.td_deque[tail];
3176 
3177   if (!__kmp_task_is_allowed(gtid, is_constrained, taskdata,
3178                              thread->th.th_current_task)) {
3179     // The TSC does not allow to steal victim task
3180     __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3181     KA_TRACE(10,
3182              ("__kmp_remove_my_task(exit #3): T#%d TSC blocks tail task: "
3183               "ntasks=%d head=%u tail=%u\n",
3184               gtid, thread_data->td.td_deque_ntasks,
3185               thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
3186     return NULL;
3187   }
3188 
3189   thread_data->td.td_deque_tail = tail;
3190   TCW_4(thread_data->td.td_deque_ntasks, thread_data->td.td_deque_ntasks - 1);
3191 
3192   __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3193 
3194   KA_TRACE(10, ("__kmp_remove_my_task(exit #4): T#%d task %p removed: "
3195                 "ntasks=%d head=%u tail=%u\n",
3196                 gtid, taskdata, thread_data->td.td_deque_ntasks,
3197                 thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
3198 
3199   task = KMP_TASKDATA_TO_TASK(taskdata);
3200   return task;
3201 }
3202 
3203 // __kmp_steal_task: remove a task from another thread's deque
3204 // Assume that calling thread has already checked existence of
3205 // task_team thread_data before calling this routine.
3206 static kmp_task_t *__kmp_steal_task(kmp_info_t *victim_thr, kmp_int32 gtid,
3207                                     kmp_task_team_t *task_team,
3208                                     std::atomic<kmp_int32> *unfinished_threads,
3209                                     int *thread_finished,
3210                                     kmp_int32 is_constrained) {
3211   kmp_task_t *task;
3212   kmp_taskdata_t *taskdata;
3213   kmp_taskdata_t *current;
3214   kmp_thread_data_t *victim_td, *threads_data;
3215   kmp_int32 target;
3216   kmp_int32 victim_tid;
3217 
3218   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
3219 
3220   threads_data = task_team->tt.tt_threads_data;
3221   KMP_DEBUG_ASSERT(threads_data != NULL); // Caller should check this condition
3222 
3223   victim_tid = victim_thr->th.th_info.ds.ds_tid;
3224   victim_td = &threads_data[victim_tid];
3225 
3226   KA_TRACE(10, ("__kmp_steal_task(enter): T#%d try to steal from T#%d: "
3227                 "task_team=%p ntasks=%d head=%u tail=%u\n",
3228                 gtid, __kmp_gtid_from_thread(victim_thr), task_team,
3229                 victim_td->td.td_deque_ntasks, victim_td->td.td_deque_head,
3230                 victim_td->td.td_deque_tail));
3231 
3232   if (TCR_4(victim_td->td.td_deque_ntasks) == 0) {
3233     KA_TRACE(10, ("__kmp_steal_task(exit #1): T#%d could not steal from T#%d: "
3234                   "task_team=%p ntasks=%d head=%u tail=%u\n",
3235                   gtid, __kmp_gtid_from_thread(victim_thr), task_team,
3236                   victim_td->td.td_deque_ntasks, victim_td->td.td_deque_head,
3237                   victim_td->td.td_deque_tail));
3238     return NULL;
3239   }
3240 
3241   __kmp_acquire_bootstrap_lock(&victim_td->td.td_deque_lock);
3242 
3243   int ntasks = TCR_4(victim_td->td.td_deque_ntasks);
3244   // Check again after we acquire the lock
3245   if (ntasks == 0) {
3246     __kmp_release_bootstrap_lock(&victim_td->td.td_deque_lock);
3247     KA_TRACE(10, ("__kmp_steal_task(exit #2): T#%d could not steal from T#%d: "
3248                   "task_team=%p ntasks=%d head=%u tail=%u\n",
3249                   gtid, __kmp_gtid_from_thread(victim_thr), task_team, ntasks,
3250                   victim_td->td.td_deque_head, victim_td->td.td_deque_tail));
3251     return NULL;
3252   }
3253 
3254   KMP_DEBUG_ASSERT(victim_td->td.td_deque != NULL);
3255   current = __kmp_threads[gtid]->th.th_current_task;
3256   taskdata = victim_td->td.td_deque[victim_td->td.td_deque_head];
3257   if (__kmp_task_is_allowed(gtid, is_constrained, taskdata, current)) {
3258     // Bump head pointer and Wrap.
3259     victim_td->td.td_deque_head =
3260         (victim_td->td.td_deque_head + 1) & TASK_DEQUE_MASK(victim_td->td);
3261   } else {
3262     if (!task_team->tt.tt_untied_task_encountered) {
3263       // The TSC does not allow to steal victim task
3264       __kmp_release_bootstrap_lock(&victim_td->td.td_deque_lock);
3265       KA_TRACE(10, ("__kmp_steal_task(exit #3): T#%d could not steal from "
3266                     "T#%d: task_team=%p ntasks=%d head=%u tail=%u\n",
3267                     gtid, __kmp_gtid_from_thread(victim_thr), task_team, ntasks,
3268                     victim_td->td.td_deque_head, victim_td->td.td_deque_tail));
3269       return NULL;
3270     }
3271     int i;
3272     // walk through victim's deque trying to steal any task
3273     target = victim_td->td.td_deque_head;
3274     taskdata = NULL;
3275     for (i = 1; i < ntasks; ++i) {
3276       target = (target + 1) & TASK_DEQUE_MASK(victim_td->td);
3277       taskdata = victim_td->td.td_deque[target];
3278       if (__kmp_task_is_allowed(gtid, is_constrained, taskdata, current)) {
3279         break; // found victim task
3280       } else {
3281         taskdata = NULL;
3282       }
3283     }
3284     if (taskdata == NULL) {
3285       // No appropriate candidate to steal found
3286       __kmp_release_bootstrap_lock(&victim_td->td.td_deque_lock);
3287       KA_TRACE(10, ("__kmp_steal_task(exit #4): T#%d could not steal from "
3288                     "T#%d: task_team=%p ntasks=%d head=%u tail=%u\n",
3289                     gtid, __kmp_gtid_from_thread(victim_thr), task_team, ntasks,
3290                     victim_td->td.td_deque_head, victim_td->td.td_deque_tail));
3291       return NULL;
3292     }
3293     int prev = target;
3294     for (i = i + 1; i < ntasks; ++i) {
3295       // shift remaining tasks in the deque left by 1
3296       target = (target + 1) & TASK_DEQUE_MASK(victim_td->td);
3297       victim_td->td.td_deque[prev] = victim_td->td.td_deque[target];
3298       prev = target;
3299     }
3300     KMP_DEBUG_ASSERT(
3301         victim_td->td.td_deque_tail ==
3302         (kmp_uint32)((target + 1) & TASK_DEQUE_MASK(victim_td->td)));
3303     victim_td->td.td_deque_tail = target; // tail -= 1 (wrapped))
3304   }
3305   if (*thread_finished) {
3306     // We need to un-mark this victim as a finished victim.  This must be done
3307     // before releasing the lock, or else other threads (starting with the
3308     // primary thread victim) might be prematurely released from the barrier!!!
3309 #if KMP_DEBUG
3310     kmp_int32 count =
3311 #endif
3312         KMP_ATOMIC_INC(unfinished_threads);
3313     KA_TRACE(
3314         20,
3315         ("__kmp_steal_task: T#%d inc unfinished_threads to %d: task_team=%p\n",
3316          gtid, count + 1, task_team));
3317     *thread_finished = FALSE;
3318   }
3319   TCW_4(victim_td->td.td_deque_ntasks, ntasks - 1);
3320 
3321   __kmp_release_bootstrap_lock(&victim_td->td.td_deque_lock);
3322 
3323   KMP_COUNT_BLOCK(TASK_stolen);
3324   KA_TRACE(10,
3325            ("__kmp_steal_task(exit #5): T#%d stole task %p from T#%d: "
3326             "task_team=%p ntasks=%d head=%u tail=%u\n",
3327             gtid, taskdata, __kmp_gtid_from_thread(victim_thr), task_team,
3328             ntasks, victim_td->td.td_deque_head, victim_td->td.td_deque_tail));
3329 
3330   task = KMP_TASKDATA_TO_TASK(taskdata);
3331   return task;
3332 }
3333 
3334 // __kmp_execute_tasks_template: Choose and execute tasks until either the
3335 // condition is statisfied (return true) or there are none left (return false).
3336 //
3337 // final_spin is TRUE if this is the spin at the release barrier.
3338 // thread_finished indicates whether the thread is finished executing all
3339 // the tasks it has on its deque, and is at the release barrier.
3340 // spinner is the location on which to spin.
3341 // spinner == NULL means only execute a single task and return.
3342 // checker is the value to check to terminate the spin.
3343 template <class C>
3344 static inline int __kmp_execute_tasks_template(
3345     kmp_info_t *thread, kmp_int32 gtid, C *flag, int final_spin,
3346     int *thread_finished USE_ITT_BUILD_ARG(void *itt_sync_obj),
3347     kmp_int32 is_constrained) {
3348   kmp_task_team_t *task_team = thread->th.th_task_team;
3349   kmp_thread_data_t *threads_data;
3350   kmp_task_t *task;
3351   kmp_info_t *other_thread;
3352   kmp_taskdata_t *current_task = thread->th.th_current_task;
3353   std::atomic<kmp_int32> *unfinished_threads;
3354   kmp_int32 nthreads, victim_tid = -2, use_own_tasks = 1, new_victim = 0,
3355                       tid = thread->th.th_info.ds.ds_tid;
3356 
3357   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
3358   KMP_DEBUG_ASSERT(thread == __kmp_threads[gtid]);
3359 
3360   if (task_team == NULL || current_task == NULL)
3361     return FALSE;
3362 
3363   KA_TRACE(15, ("__kmp_execute_tasks_template(enter): T#%d final_spin=%d "
3364                 "*thread_finished=%d\n",
3365                 gtid, final_spin, *thread_finished));
3366 
3367   thread->th.th_reap_state = KMP_NOT_SAFE_TO_REAP;
3368   threads_data = (kmp_thread_data_t *)TCR_PTR(task_team->tt.tt_threads_data);
3369 
3370   KMP_DEBUG_ASSERT(threads_data != NULL);
3371 
3372   nthreads = task_team->tt.tt_nproc;
3373   unfinished_threads = &(task_team->tt.tt_unfinished_threads);
3374   KMP_DEBUG_ASSERT(nthreads > 1 || task_team->tt.tt_found_proxy_tasks ||
3375                    task_team->tt.tt_hidden_helper_task_encountered);
3376   KMP_DEBUG_ASSERT(*unfinished_threads >= 0);
3377 
3378   while (1) { // Outer loop keeps trying to find tasks in case of single thread
3379     // getting tasks from target constructs
3380     while (1) { // Inner loop to find a task and execute it
3381       task = NULL;
3382       if (task_team->tt.tt_num_task_pri) { // get priority task first
3383         task = __kmp_get_priority_task(gtid, task_team, is_constrained);
3384       }
3385       if (task == NULL && use_own_tasks) { // check own queue next
3386         task = __kmp_remove_my_task(thread, gtid, task_team, is_constrained);
3387       }
3388       if ((task == NULL) && (nthreads > 1)) { // Steal a task finally
3389         int asleep = 1;
3390         use_own_tasks = 0;
3391         // Try to steal from the last place I stole from successfully.
3392         if (victim_tid == -2) { // haven't stolen anything yet
3393           victim_tid = threads_data[tid].td.td_deque_last_stolen;
3394           if (victim_tid !=
3395               -1) // if we have a last stolen from victim, get the thread
3396             other_thread = threads_data[victim_tid].td.td_thr;
3397         }
3398         if (victim_tid != -1) { // found last victim
3399           asleep = 0;
3400         } else if (!new_victim) { // no recent steals and we haven't already
3401           // used a new victim; select a random thread
3402           do { // Find a different thread to steal work from.
3403             // Pick a random thread. Initial plan was to cycle through all the
3404             // threads, and only return if we tried to steal from every thread,
3405             // and failed.  Arch says that's not such a great idea.
3406             victim_tid = __kmp_get_random(thread) % (nthreads - 1);
3407             if (victim_tid >= tid) {
3408               ++victim_tid; // Adjusts random distribution to exclude self
3409             }
3410             // Found a potential victim
3411             other_thread = threads_data[victim_tid].td.td_thr;
3412             // There is a slight chance that __kmp_enable_tasking() did not wake
3413             // up all threads waiting at the barrier.  If victim is sleeping,
3414             // then wake it up. Since we were going to pay the cache miss
3415             // penalty for referencing another thread's kmp_info_t struct
3416             // anyway,
3417             // the check shouldn't cost too much performance at this point. In
3418             // extra barrier mode, tasks do not sleep at the separate tasking
3419             // barrier, so this isn't a problem.
3420             asleep = 0;
3421             if ((__kmp_tasking_mode == tskm_task_teams) &&
3422                 (__kmp_dflt_blocktime != KMP_MAX_BLOCKTIME) &&
3423                 (TCR_PTR(CCAST(void *, other_thread->th.th_sleep_loc)) !=
3424                  NULL)) {
3425               asleep = 1;
3426               __kmp_null_resume_wrapper(other_thread);
3427               // A sleeping thread should not have any tasks on it's queue.
3428               // There is a slight possibility that it resumes, steals a task
3429               // from another thread, which spawns more tasks, all in the time
3430               // that it takes this thread to check => don't write an assertion
3431               // that the victim's queue is empty.  Try stealing from a
3432               // different thread.
3433             }
3434           } while (asleep);
3435         }
3436 
3437         if (!asleep) {
3438           // We have a victim to try to steal from
3439           task = __kmp_steal_task(other_thread, gtid, task_team,
3440                                   unfinished_threads, thread_finished,
3441                                   is_constrained);
3442         }
3443         if (task != NULL) { // set last stolen to victim
3444           if (threads_data[tid].td.td_deque_last_stolen != victim_tid) {
3445             threads_data[tid].td.td_deque_last_stolen = victim_tid;
3446             // The pre-refactored code did not try more than 1 successful new
3447             // vicitm, unless the last one generated more local tasks;
3448             // new_victim keeps track of this
3449             new_victim = 1;
3450           }
3451         } else { // No tasks found; unset last_stolen
3452           KMP_CHECK_UPDATE(threads_data[tid].td.td_deque_last_stolen, -1);
3453           victim_tid = -2; // no successful victim found
3454         }
3455       }
3456 
3457       if (task == NULL)
3458         break; // break out of tasking loop
3459 
3460 // Found a task; execute it
3461 #if USE_ITT_BUILD && USE_ITT_NOTIFY
3462       if (__itt_sync_create_ptr || KMP_ITT_DEBUG) {
3463         if (itt_sync_obj == NULL) { // we are at fork barrier where we could not
3464           // get the object reliably
3465           itt_sync_obj = __kmp_itt_barrier_object(gtid, bs_forkjoin_barrier);
3466         }
3467         __kmp_itt_task_starting(itt_sync_obj);
3468       }
3469 #endif /* USE_ITT_BUILD && USE_ITT_NOTIFY */
3470       __kmp_invoke_task(gtid, task, current_task);
3471 #if USE_ITT_BUILD
3472       if (itt_sync_obj != NULL)
3473         __kmp_itt_task_finished(itt_sync_obj);
3474 #endif /* USE_ITT_BUILD */
3475       // If this thread is only partway through the barrier and the condition is
3476       // met, then return now, so that the barrier gather/release pattern can
3477       // proceed. If this thread is in the last spin loop in the barrier,
3478       // waiting to be released, we know that the termination condition will not
3479       // be satisfied, so don't waste any cycles checking it.
3480       if (flag == NULL || (!final_spin && flag->done_check())) {
3481         KA_TRACE(
3482             15,
3483             ("__kmp_execute_tasks_template: T#%d spin condition satisfied\n",
3484              gtid));
3485         return TRUE;
3486       }
3487       if (thread->th.th_task_team == NULL) {
3488         break;
3489       }
3490       KMP_YIELD(__kmp_library == library_throughput); // Yield before next task
3491       // If execution of a stolen task results in more tasks being placed on our
3492       // run queue, reset use_own_tasks
3493       if (!use_own_tasks && TCR_4(threads_data[tid].td.td_deque_ntasks) != 0) {
3494         KA_TRACE(20, ("__kmp_execute_tasks_template: T#%d stolen task spawned "
3495                       "other tasks, restart\n",
3496                       gtid));
3497         use_own_tasks = 1;
3498         new_victim = 0;
3499       }
3500     }
3501 
3502     // The task source has been exhausted. If in final spin loop of barrier,
3503     // check if termination condition is satisfied. The work queue may be empty
3504     // but there might be proxy tasks still executing.
3505     if (final_spin &&
3506         KMP_ATOMIC_LD_ACQ(&current_task->td_incomplete_child_tasks) == 0) {
3507       // First, decrement the #unfinished threads, if that has not already been
3508       // done.  This decrement might be to the spin location, and result in the
3509       // termination condition being satisfied.
3510       if (!*thread_finished) {
3511 #if KMP_DEBUG
3512         kmp_int32 count = -1 +
3513 #endif
3514             KMP_ATOMIC_DEC(unfinished_threads);
3515         KA_TRACE(20, ("__kmp_execute_tasks_template: T#%d dec "
3516                       "unfinished_threads to %d task_team=%p\n",
3517                       gtid, count, task_team));
3518         *thread_finished = TRUE;
3519       }
3520 
3521       // It is now unsafe to reference thread->th.th_team !!!
3522       // Decrementing task_team->tt.tt_unfinished_threads can allow the primary
3523       // thread to pass through the barrier, where it might reset each thread's
3524       // th.th_team field for the next parallel region. If we can steal more
3525       // work, we know that this has not happened yet.
3526       if (flag != NULL && flag->done_check()) {
3527         KA_TRACE(
3528             15,
3529             ("__kmp_execute_tasks_template: T#%d spin condition satisfied\n",
3530              gtid));
3531         return TRUE;
3532       }
3533     }
3534 
3535     // If this thread's task team is NULL, primary thread has recognized that
3536     // there are no more tasks; bail out
3537     if (thread->th.th_task_team == NULL) {
3538       KA_TRACE(15,
3539                ("__kmp_execute_tasks_template: T#%d no more tasks\n", gtid));
3540       return FALSE;
3541     }
3542 
3543     // Check the flag again to see if it has already done in case to be trapped
3544     // into infinite loop when a if0 task depends on a hidden helper task
3545     // outside any parallel region. Detached tasks are not impacted in this case
3546     // because the only thread executing this function has to execute the proxy
3547     // task so it is in another code path that has the same check.
3548     if (flag == NULL || (!final_spin && flag->done_check())) {
3549       KA_TRACE(15,
3550                ("__kmp_execute_tasks_template: T#%d spin condition satisfied\n",
3551                 gtid));
3552       return TRUE;
3553     }
3554 
3555     // We could be getting tasks from target constructs; if this is the only
3556     // thread, keep trying to execute tasks from own queue
3557     if (nthreads == 1 &&
3558         KMP_ATOMIC_LD_ACQ(&current_task->td_incomplete_child_tasks))
3559       use_own_tasks = 1;
3560     else {
3561       KA_TRACE(15,
3562                ("__kmp_execute_tasks_template: T#%d can't find work\n", gtid));
3563       return FALSE;
3564     }
3565   }
3566 }
3567 
3568 template <bool C, bool S>
3569 int __kmp_execute_tasks_32(
3570     kmp_info_t *thread, kmp_int32 gtid, kmp_flag_32<C, S> *flag, int final_spin,
3571     int *thread_finished USE_ITT_BUILD_ARG(void *itt_sync_obj),
3572     kmp_int32 is_constrained) {
3573   return __kmp_execute_tasks_template(
3574       thread, gtid, flag, final_spin,
3575       thread_finished USE_ITT_BUILD_ARG(itt_sync_obj), is_constrained);
3576 }
3577 
3578 template <bool C, bool S>
3579 int __kmp_execute_tasks_64(
3580     kmp_info_t *thread, kmp_int32 gtid, kmp_flag_64<C, S> *flag, int final_spin,
3581     int *thread_finished USE_ITT_BUILD_ARG(void *itt_sync_obj),
3582     kmp_int32 is_constrained) {
3583   return __kmp_execute_tasks_template(
3584       thread, gtid, flag, final_spin,
3585       thread_finished USE_ITT_BUILD_ARG(itt_sync_obj), is_constrained);
3586 }
3587 
3588 template <bool C, bool S>
3589 int __kmp_atomic_execute_tasks_64(
3590     kmp_info_t *thread, kmp_int32 gtid, kmp_atomic_flag_64<C, S> *flag,
3591     int final_spin, int *thread_finished USE_ITT_BUILD_ARG(void *itt_sync_obj),
3592     kmp_int32 is_constrained) {
3593   return __kmp_execute_tasks_template(
3594       thread, gtid, flag, final_spin,
3595       thread_finished USE_ITT_BUILD_ARG(itt_sync_obj), is_constrained);
3596 }
3597 
3598 int __kmp_execute_tasks_oncore(
3599     kmp_info_t *thread, kmp_int32 gtid, kmp_flag_oncore *flag, int final_spin,
3600     int *thread_finished USE_ITT_BUILD_ARG(void *itt_sync_obj),
3601     kmp_int32 is_constrained) {
3602   return __kmp_execute_tasks_template(
3603       thread, gtid, flag, final_spin,
3604       thread_finished USE_ITT_BUILD_ARG(itt_sync_obj), is_constrained);
3605 }
3606 
3607 template int
3608 __kmp_execute_tasks_32<false, false>(kmp_info_t *, kmp_int32,
3609                                      kmp_flag_32<false, false> *, int,
3610                                      int *USE_ITT_BUILD_ARG(void *), kmp_int32);
3611 
3612 template int __kmp_execute_tasks_64<false, true>(kmp_info_t *, kmp_int32,
3613                                                  kmp_flag_64<false, true> *,
3614                                                  int,
3615                                                  int *USE_ITT_BUILD_ARG(void *),
3616                                                  kmp_int32);
3617 
3618 template int __kmp_execute_tasks_64<true, false>(kmp_info_t *, kmp_int32,
3619                                                  kmp_flag_64<true, false> *,
3620                                                  int,
3621                                                  int *USE_ITT_BUILD_ARG(void *),
3622                                                  kmp_int32);
3623 
3624 template int __kmp_atomic_execute_tasks_64<false, true>(
3625     kmp_info_t *, kmp_int32, kmp_atomic_flag_64<false, true> *, int,
3626     int *USE_ITT_BUILD_ARG(void *), kmp_int32);
3627 
3628 template int __kmp_atomic_execute_tasks_64<true, false>(
3629     kmp_info_t *, kmp_int32, kmp_atomic_flag_64<true, false> *, int,
3630     int *USE_ITT_BUILD_ARG(void *), kmp_int32);
3631 
3632 // __kmp_enable_tasking: Allocate task team and resume threads sleeping at the
3633 // next barrier so they can assist in executing enqueued tasks.
3634 // First thread in allocates the task team atomically.
3635 static void __kmp_enable_tasking(kmp_task_team_t *task_team,
3636                                  kmp_info_t *this_thr) {
3637   kmp_thread_data_t *threads_data;
3638   int nthreads, i, is_init_thread;
3639 
3640   KA_TRACE(10, ("__kmp_enable_tasking(enter): T#%d\n",
3641                 __kmp_gtid_from_thread(this_thr)));
3642 
3643   KMP_DEBUG_ASSERT(task_team != NULL);
3644   KMP_DEBUG_ASSERT(this_thr->th.th_team != NULL);
3645 
3646   nthreads = task_team->tt.tt_nproc;
3647   KMP_DEBUG_ASSERT(nthreads > 0);
3648   KMP_DEBUG_ASSERT(nthreads == this_thr->th.th_team->t.t_nproc);
3649 
3650   // Allocate or increase the size of threads_data if necessary
3651   is_init_thread = __kmp_realloc_task_threads_data(this_thr, task_team);
3652 
3653   if (!is_init_thread) {
3654     // Some other thread already set up the array.
3655     KA_TRACE(
3656         20,
3657         ("__kmp_enable_tasking(exit): T#%d: threads array already set up.\n",
3658          __kmp_gtid_from_thread(this_thr)));
3659     return;
3660   }
3661   threads_data = (kmp_thread_data_t *)TCR_PTR(task_team->tt.tt_threads_data);
3662   KMP_DEBUG_ASSERT(threads_data != NULL);
3663 
3664   if (__kmp_tasking_mode == tskm_task_teams &&
3665       (__kmp_dflt_blocktime != KMP_MAX_BLOCKTIME)) {
3666     // Release any threads sleeping at the barrier, so that they can steal
3667     // tasks and execute them.  In extra barrier mode, tasks do not sleep
3668     // at the separate tasking barrier, so this isn't a problem.
3669     for (i = 0; i < nthreads; i++) {
3670       void *sleep_loc;
3671       kmp_info_t *thread = threads_data[i].td.td_thr;
3672 
3673       if (i == this_thr->th.th_info.ds.ds_tid) {
3674         continue;
3675       }
3676       // Since we haven't locked the thread's suspend mutex lock at this
3677       // point, there is a small window where a thread might be putting
3678       // itself to sleep, but hasn't set the th_sleep_loc field yet.
3679       // To work around this, __kmp_execute_tasks_template() periodically checks
3680       // see if other threads are sleeping (using the same random mechanism that
3681       // is used for task stealing) and awakens them if they are.
3682       if ((sleep_loc = TCR_PTR(CCAST(void *, thread->th.th_sleep_loc))) !=
3683           NULL) {
3684         KF_TRACE(50, ("__kmp_enable_tasking: T#%d waking up thread T#%d\n",
3685                       __kmp_gtid_from_thread(this_thr),
3686                       __kmp_gtid_from_thread(thread)));
3687         __kmp_null_resume_wrapper(thread);
3688       } else {
3689         KF_TRACE(50, ("__kmp_enable_tasking: T#%d don't wake up thread T#%d\n",
3690                       __kmp_gtid_from_thread(this_thr),
3691                       __kmp_gtid_from_thread(thread)));
3692       }
3693     }
3694   }
3695 
3696   KA_TRACE(10, ("__kmp_enable_tasking(exit): T#%d\n",
3697                 __kmp_gtid_from_thread(this_thr)));
3698 }
3699 
3700 /* // TODO: Check the comment consistency
3701  * Utility routines for "task teams".  A task team (kmp_task_t) is kind of
3702  * like a shadow of the kmp_team_t data struct, with a different lifetime.
3703  * After a child * thread checks into a barrier and calls __kmp_release() from
3704  * the particular variant of __kmp_<barrier_kind>_barrier_gather(), it can no
3705  * longer assume that the kmp_team_t structure is intact (at any moment, the
3706  * primary thread may exit the barrier code and free the team data structure,
3707  * and return the threads to the thread pool).
3708  *
3709  * This does not work with the tasking code, as the thread is still
3710  * expected to participate in the execution of any tasks that may have been
3711  * spawned my a member of the team, and the thread still needs access to all
3712  * to each thread in the team, so that it can steal work from it.
3713  *
3714  * Enter the existence of the kmp_task_team_t struct.  It employs a reference
3715  * counting mechanism, and is allocated by the primary thread before calling
3716  * __kmp_<barrier_kind>_release, and then is release by the last thread to
3717  * exit __kmp_<barrier_kind>_release at the next barrier.  I.e. the lifetimes
3718  * of the kmp_task_team_t structs for consecutive barriers can overlap
3719  * (and will, unless the primary thread is the last thread to exit the barrier
3720  * release phase, which is not typical). The existence of such a struct is
3721  * useful outside the context of tasking.
3722  *
3723  * We currently use the existence of the threads array as an indicator that
3724  * tasks were spawned since the last barrier.  If the structure is to be
3725  * useful outside the context of tasking, then this will have to change, but
3726  * not setting the field minimizes the performance impact of tasking on
3727  * barriers, when no explicit tasks were spawned (pushed, actually).
3728  */
3729 
3730 static kmp_task_team_t *__kmp_free_task_teams =
3731     NULL; // Free list for task_team data structures
3732 // Lock for task team data structures
3733 kmp_bootstrap_lock_t __kmp_task_team_lock =
3734     KMP_BOOTSTRAP_LOCK_INITIALIZER(__kmp_task_team_lock);
3735 
3736 // __kmp_alloc_task_deque:
3737 // Allocates a task deque for a particular thread, and initialize the necessary
3738 // data structures relating to the deque.  This only happens once per thread
3739 // per task team since task teams are recycled. No lock is needed during
3740 // allocation since each thread allocates its own deque.
3741 static void __kmp_alloc_task_deque(kmp_info_t *thread,
3742                                    kmp_thread_data_t *thread_data) {
3743   __kmp_init_bootstrap_lock(&thread_data->td.td_deque_lock);
3744   KMP_DEBUG_ASSERT(thread_data->td.td_deque == NULL);
3745 
3746   // Initialize last stolen task field to "none"
3747   thread_data->td.td_deque_last_stolen = -1;
3748 
3749   KMP_DEBUG_ASSERT(TCR_4(thread_data->td.td_deque_ntasks) == 0);
3750   KMP_DEBUG_ASSERT(thread_data->td.td_deque_head == 0);
3751   KMP_DEBUG_ASSERT(thread_data->td.td_deque_tail == 0);
3752 
3753   KE_TRACE(
3754       10,
3755       ("__kmp_alloc_task_deque: T#%d allocating deque[%d] for thread_data %p\n",
3756        __kmp_gtid_from_thread(thread), INITIAL_TASK_DEQUE_SIZE, thread_data));
3757   // Allocate space for task deque, and zero the deque
3758   // Cannot use __kmp_thread_calloc() because threads not around for
3759   // kmp_reap_task_team( ).
3760   thread_data->td.td_deque = (kmp_taskdata_t **)__kmp_allocate(
3761       INITIAL_TASK_DEQUE_SIZE * sizeof(kmp_taskdata_t *));
3762   thread_data->td.td_deque_size = INITIAL_TASK_DEQUE_SIZE;
3763 }
3764 
3765 // __kmp_free_task_deque:
3766 // Deallocates a task deque for a particular thread. Happens at library
3767 // deallocation so don't need to reset all thread data fields.
3768 static void __kmp_free_task_deque(kmp_thread_data_t *thread_data) {
3769   if (thread_data->td.td_deque != NULL) {
3770     __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
3771     TCW_4(thread_data->td.td_deque_ntasks, 0);
3772     __kmp_free(thread_data->td.td_deque);
3773     thread_data->td.td_deque = NULL;
3774     __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
3775   }
3776 
3777 #ifdef BUILD_TIED_TASK_STACK
3778   // GEH: Figure out what to do here for td_susp_tied_tasks
3779   if (thread_data->td.td_susp_tied_tasks.ts_entries != TASK_STACK_EMPTY) {
3780     __kmp_free_task_stack(__kmp_thread_from_gtid(gtid), thread_data);
3781   }
3782 #endif // BUILD_TIED_TASK_STACK
3783 }
3784 
3785 // __kmp_realloc_task_threads_data:
3786 // Allocates a threads_data array for a task team, either by allocating an
3787 // initial array or enlarging an existing array.  Only the first thread to get
3788 // the lock allocs or enlarges the array and re-initializes the array elements.
3789 // That thread returns "TRUE", the rest return "FALSE".
3790 // Assumes that the new array size is given by task_team -> tt.tt_nproc.
3791 // The current size is given by task_team -> tt.tt_max_threads.
3792 static int __kmp_realloc_task_threads_data(kmp_info_t *thread,
3793                                            kmp_task_team_t *task_team) {
3794   kmp_thread_data_t **threads_data_p;
3795   kmp_int32 nthreads, maxthreads;
3796   int is_init_thread = FALSE;
3797 
3798   if (TCR_4(task_team->tt.tt_found_tasks)) {
3799     // Already reallocated and initialized.
3800     return FALSE;
3801   }
3802 
3803   threads_data_p = &task_team->tt.tt_threads_data;
3804   nthreads = task_team->tt.tt_nproc;
3805   maxthreads = task_team->tt.tt_max_threads;
3806 
3807   // All threads must lock when they encounter the first task of the implicit
3808   // task region to make sure threads_data fields are (re)initialized before
3809   // used.
3810   __kmp_acquire_bootstrap_lock(&task_team->tt.tt_threads_lock);
3811 
3812   if (!TCR_4(task_team->tt.tt_found_tasks)) {
3813     // first thread to enable tasking
3814     kmp_team_t *team = thread->th.th_team;
3815     int i;
3816 
3817     is_init_thread = TRUE;
3818     if (maxthreads < nthreads) {
3819 
3820       if (*threads_data_p != NULL) {
3821         kmp_thread_data_t *old_data = *threads_data_p;
3822         kmp_thread_data_t *new_data = NULL;
3823 
3824         KE_TRACE(
3825             10,
3826             ("__kmp_realloc_task_threads_data: T#%d reallocating "
3827              "threads data for task_team %p, new_size = %d, old_size = %d\n",
3828              __kmp_gtid_from_thread(thread), task_team, nthreads, maxthreads));
3829         // Reallocate threads_data to have more elements than current array
3830         // Cannot use __kmp_thread_realloc() because threads not around for
3831         // kmp_reap_task_team( ).  Note all new array entries are initialized
3832         // to zero by __kmp_allocate().
3833         new_data = (kmp_thread_data_t *)__kmp_allocate(
3834             nthreads * sizeof(kmp_thread_data_t));
3835         // copy old data to new data
3836         KMP_MEMCPY_S((void *)new_data, nthreads * sizeof(kmp_thread_data_t),
3837                      (void *)old_data, maxthreads * sizeof(kmp_thread_data_t));
3838 
3839 #ifdef BUILD_TIED_TASK_STACK
3840         // GEH: Figure out if this is the right thing to do
3841         for (i = maxthreads; i < nthreads; i++) {
3842           kmp_thread_data_t *thread_data = &(*threads_data_p)[i];
3843           __kmp_init_task_stack(__kmp_gtid_from_thread(thread), thread_data);
3844         }
3845 #endif // BUILD_TIED_TASK_STACK
3846        // Install the new data and free the old data
3847         (*threads_data_p) = new_data;
3848         __kmp_free(old_data);
3849       } else {
3850         KE_TRACE(10, ("__kmp_realloc_task_threads_data: T#%d allocating "
3851                       "threads data for task_team %p, size = %d\n",
3852                       __kmp_gtid_from_thread(thread), task_team, nthreads));
3853         // Make the initial allocate for threads_data array, and zero entries
3854         // Cannot use __kmp_thread_calloc() because threads not around for
3855         // kmp_reap_task_team( ).
3856         *threads_data_p = (kmp_thread_data_t *)__kmp_allocate(
3857             nthreads * sizeof(kmp_thread_data_t));
3858 #ifdef BUILD_TIED_TASK_STACK
3859         // GEH: Figure out if this is the right thing to do
3860         for (i = 0; i < nthreads; i++) {
3861           kmp_thread_data_t *thread_data = &(*threads_data_p)[i];
3862           __kmp_init_task_stack(__kmp_gtid_from_thread(thread), thread_data);
3863         }
3864 #endif // BUILD_TIED_TASK_STACK
3865       }
3866       task_team->tt.tt_max_threads = nthreads;
3867     } else {
3868       // If array has (more than) enough elements, go ahead and use it
3869       KMP_DEBUG_ASSERT(*threads_data_p != NULL);
3870     }
3871 
3872     // initialize threads_data pointers back to thread_info structures
3873     for (i = 0; i < nthreads; i++) {
3874       kmp_thread_data_t *thread_data = &(*threads_data_p)[i];
3875       thread_data->td.td_thr = team->t.t_threads[i];
3876 
3877       if (thread_data->td.td_deque_last_stolen >= nthreads) {
3878         // The last stolen field survives across teams / barrier, and the number
3879         // of threads may have changed.  It's possible (likely?) that a new
3880         // parallel region will exhibit the same behavior as previous region.
3881         thread_data->td.td_deque_last_stolen = -1;
3882       }
3883     }
3884 
3885     KMP_MB();
3886     TCW_SYNC_4(task_team->tt.tt_found_tasks, TRUE);
3887   }
3888 
3889   __kmp_release_bootstrap_lock(&task_team->tt.tt_threads_lock);
3890   return is_init_thread;
3891 }
3892 
3893 // __kmp_free_task_threads_data:
3894 // Deallocates a threads_data array for a task team, including any attached
3895 // tasking deques.  Only occurs at library shutdown.
3896 static void __kmp_free_task_threads_data(kmp_task_team_t *task_team) {
3897   __kmp_acquire_bootstrap_lock(&task_team->tt.tt_threads_lock);
3898   if (task_team->tt.tt_threads_data != NULL) {
3899     int i;
3900     for (i = 0; i < task_team->tt.tt_max_threads; i++) {
3901       __kmp_free_task_deque(&task_team->tt.tt_threads_data[i]);
3902     }
3903     __kmp_free(task_team->tt.tt_threads_data);
3904     task_team->tt.tt_threads_data = NULL;
3905   }
3906   __kmp_release_bootstrap_lock(&task_team->tt.tt_threads_lock);
3907 }
3908 
3909 // __kmp_free_task_pri_list:
3910 // Deallocates tasking deques used for priority tasks.
3911 // Only occurs at library shutdown.
3912 static void __kmp_free_task_pri_list(kmp_task_team_t *task_team) {
3913   __kmp_acquire_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
3914   if (task_team->tt.tt_task_pri_list != NULL) {
3915     kmp_task_pri_t *list = task_team->tt.tt_task_pri_list;
3916     while (list != NULL) {
3917       kmp_task_pri_t *next = list->next;
3918       __kmp_free_task_deque(&list->td);
3919       __kmp_free(list);
3920       list = next;
3921     }
3922     task_team->tt.tt_task_pri_list = NULL;
3923   }
3924   __kmp_release_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
3925 }
3926 
3927 // __kmp_allocate_task_team:
3928 // Allocates a task team associated with a specific team, taking it from
3929 // the global task team free list if possible.  Also initializes data
3930 // structures.
3931 static kmp_task_team_t *__kmp_allocate_task_team(kmp_info_t *thread,
3932                                                  kmp_team_t *team) {
3933   kmp_task_team_t *task_team = NULL;
3934   int nthreads;
3935 
3936   KA_TRACE(20, ("__kmp_allocate_task_team: T#%d entering; team = %p\n",
3937                 (thread ? __kmp_gtid_from_thread(thread) : -1), team));
3938 
3939   if (TCR_PTR(__kmp_free_task_teams) != NULL) {
3940     // Take a task team from the task team pool
3941     __kmp_acquire_bootstrap_lock(&__kmp_task_team_lock);
3942     if (__kmp_free_task_teams != NULL) {
3943       task_team = __kmp_free_task_teams;
3944       TCW_PTR(__kmp_free_task_teams, task_team->tt.tt_next);
3945       task_team->tt.tt_next = NULL;
3946     }
3947     __kmp_release_bootstrap_lock(&__kmp_task_team_lock);
3948   }
3949 
3950   if (task_team == NULL) {
3951     KE_TRACE(10, ("__kmp_allocate_task_team: T#%d allocating "
3952                   "task team for team %p\n",
3953                   __kmp_gtid_from_thread(thread), team));
3954     // Allocate a new task team if one is not available. Cannot use
3955     // __kmp_thread_malloc because threads not around for kmp_reap_task_team.
3956     task_team = (kmp_task_team_t *)__kmp_allocate(sizeof(kmp_task_team_t));
3957     __kmp_init_bootstrap_lock(&task_team->tt.tt_threads_lock);
3958     __kmp_init_bootstrap_lock(&task_team->tt.tt_task_pri_lock);
3959 #if USE_ITT_BUILD && USE_ITT_NOTIFY && KMP_DEBUG
3960     // suppress race conditions detection on synchronization flags in debug mode
3961     // this helps to analyze library internals eliminating false positives
3962     __itt_suppress_mark_range(
3963         __itt_suppress_range, __itt_suppress_threading_errors,
3964         &task_team->tt.tt_found_tasks, sizeof(task_team->tt.tt_found_tasks));
3965     __itt_suppress_mark_range(__itt_suppress_range,
3966                               __itt_suppress_threading_errors,
3967                               CCAST(kmp_uint32 *, &task_team->tt.tt_active),
3968                               sizeof(task_team->tt.tt_active));
3969 #endif /* USE_ITT_BUILD && USE_ITT_NOTIFY && KMP_DEBUG */
3970     // Note: __kmp_allocate zeroes returned memory, othewise we would need:
3971     // task_team->tt.tt_threads_data = NULL;
3972     // task_team->tt.tt_max_threads = 0;
3973     // task_team->tt.tt_next = NULL;
3974   }
3975 
3976   TCW_4(task_team->tt.tt_found_tasks, FALSE);
3977   TCW_4(task_team->tt.tt_found_proxy_tasks, FALSE);
3978   TCW_4(task_team->tt.tt_hidden_helper_task_encountered, FALSE);
3979   task_team->tt.tt_nproc = nthreads = team->t.t_nproc;
3980 
3981   KMP_ATOMIC_ST_REL(&task_team->tt.tt_unfinished_threads, nthreads);
3982   TCW_4(task_team->tt.tt_hidden_helper_task_encountered, FALSE);
3983   TCW_4(task_team->tt.tt_active, TRUE);
3984 
3985   KA_TRACE(20, ("__kmp_allocate_task_team: T#%d exiting; task_team = %p "
3986                 "unfinished_threads init'd to %d\n",
3987                 (thread ? __kmp_gtid_from_thread(thread) : -1), task_team,
3988                 KMP_ATOMIC_LD_RLX(&task_team->tt.tt_unfinished_threads)));
3989   return task_team;
3990 }
3991 
3992 // __kmp_free_task_team:
3993 // Frees the task team associated with a specific thread, and adds it
3994 // to the global task team free list.
3995 void __kmp_free_task_team(kmp_info_t *thread, kmp_task_team_t *task_team) {
3996   KA_TRACE(20, ("__kmp_free_task_team: T#%d task_team = %p\n",
3997                 thread ? __kmp_gtid_from_thread(thread) : -1, task_team));
3998 
3999   // Put task team back on free list
4000   __kmp_acquire_bootstrap_lock(&__kmp_task_team_lock);
4001 
4002   KMP_DEBUG_ASSERT(task_team->tt.tt_next == NULL);
4003   task_team->tt.tt_next = __kmp_free_task_teams;
4004   TCW_PTR(__kmp_free_task_teams, task_team);
4005 
4006   __kmp_release_bootstrap_lock(&__kmp_task_team_lock);
4007 }
4008 
4009 // __kmp_reap_task_teams:
4010 // Free all the task teams on the task team free list.
4011 // Should only be done during library shutdown.
4012 // Cannot do anything that needs a thread structure or gtid since they are
4013 // already gone.
4014 void __kmp_reap_task_teams(void) {
4015   kmp_task_team_t *task_team;
4016 
4017   if (TCR_PTR(__kmp_free_task_teams) != NULL) {
4018     // Free all task_teams on the free list
4019     __kmp_acquire_bootstrap_lock(&__kmp_task_team_lock);
4020     while ((task_team = __kmp_free_task_teams) != NULL) {
4021       __kmp_free_task_teams = task_team->tt.tt_next;
4022       task_team->tt.tt_next = NULL;
4023 
4024       // Free threads_data if necessary
4025       if (task_team->tt.tt_threads_data != NULL) {
4026         __kmp_free_task_threads_data(task_team);
4027       }
4028       if (task_team->tt.tt_task_pri_list != NULL) {
4029         __kmp_free_task_pri_list(task_team);
4030       }
4031       __kmp_free(task_team);
4032     }
4033     __kmp_release_bootstrap_lock(&__kmp_task_team_lock);
4034   }
4035 }
4036 
4037 // __kmp_wait_to_unref_task_teams:
4038 // Some threads could still be in the fork barrier release code, possibly
4039 // trying to steal tasks.  Wait for each thread to unreference its task team.
4040 void __kmp_wait_to_unref_task_teams(void) {
4041   kmp_info_t *thread;
4042   kmp_uint32 spins;
4043   kmp_uint64 time;
4044   int done;
4045 
4046   KMP_INIT_YIELD(spins);
4047   KMP_INIT_BACKOFF(time);
4048 
4049   for (;;) {
4050     done = TRUE;
4051 
4052     // TODO: GEH - this may be is wrong because some sync would be necessary
4053     // in case threads are added to the pool during the traversal. Need to
4054     // verify that lock for thread pool is held when calling this routine.
4055     for (thread = CCAST(kmp_info_t *, __kmp_thread_pool); thread != NULL;
4056          thread = thread->th.th_next_pool) {
4057 #if KMP_OS_WINDOWS
4058       DWORD exit_val;
4059 #endif
4060       if (TCR_PTR(thread->th.th_task_team) == NULL) {
4061         KA_TRACE(10, ("__kmp_wait_to_unref_task_team: T#%d task_team == NULL\n",
4062                       __kmp_gtid_from_thread(thread)));
4063         continue;
4064       }
4065 #if KMP_OS_WINDOWS
4066       // TODO: GEH - add this check for Linux* OS / OS X* as well?
4067       if (!__kmp_is_thread_alive(thread, &exit_val)) {
4068         thread->th.th_task_team = NULL;
4069         continue;
4070       }
4071 #endif
4072 
4073       done = FALSE; // Because th_task_team pointer is not NULL for this thread
4074 
4075       KA_TRACE(10, ("__kmp_wait_to_unref_task_team: Waiting for T#%d to "
4076                     "unreference task_team\n",
4077                     __kmp_gtid_from_thread(thread)));
4078 
4079       if (__kmp_dflt_blocktime != KMP_MAX_BLOCKTIME) {
4080         void *sleep_loc;
4081         // If the thread is sleeping, awaken it.
4082         if ((sleep_loc = TCR_PTR(CCAST(void *, thread->th.th_sleep_loc))) !=
4083             NULL) {
4084           KA_TRACE(
4085               10,
4086               ("__kmp_wait_to_unref_task_team: T#%d waking up thread T#%d\n",
4087                __kmp_gtid_from_thread(thread), __kmp_gtid_from_thread(thread)));
4088           __kmp_null_resume_wrapper(thread);
4089         }
4090       }
4091     }
4092     if (done) {
4093       break;
4094     }
4095 
4096     // If oversubscribed or have waited a bit, yield.
4097     KMP_YIELD_OVERSUB_ELSE_SPIN(spins, time);
4098   }
4099 }
4100 
4101 void __kmp_shift_task_state_stack(kmp_info_t *this_thr, kmp_uint8 value) {
4102   // Shift values from th_task_state_top+1 to task_state_stack_sz
4103   if (this_thr->th.th_task_state_top + 1 >=
4104       this_thr->th.th_task_state_stack_sz) { // increase size
4105     kmp_uint32 new_size = 2 * this_thr->th.th_task_state_stack_sz;
4106     kmp_uint8 *old_stack, *new_stack;
4107     kmp_uint32 i;
4108     new_stack = (kmp_uint8 *)__kmp_allocate(new_size);
4109     for (i = 0; i <= this_thr->th.th_task_state_top; ++i) {
4110       new_stack[i] = this_thr->th.th_task_state_memo_stack[i];
4111     }
4112     // If we need to reallocate do the shift at the same time.
4113     for (; i < this_thr->th.th_task_state_stack_sz; ++i) {
4114       new_stack[i + 1] = this_thr->th.th_task_state_memo_stack[i];
4115     }
4116     for (i = this_thr->th.th_task_state_stack_sz; i < new_size;
4117          ++i) { // zero-init rest of stack
4118       new_stack[i] = 0;
4119     }
4120     old_stack = this_thr->th.th_task_state_memo_stack;
4121     this_thr->th.th_task_state_memo_stack = new_stack;
4122     this_thr->th.th_task_state_stack_sz = new_size;
4123     __kmp_free(old_stack);
4124   } else {
4125     kmp_uint8 *end;
4126     kmp_uint32 i;
4127 
4128     end = &this_thr->th
4129                .th_task_state_memo_stack[this_thr->th.th_task_state_stack_sz];
4130 
4131     for (i = this_thr->th.th_task_state_stack_sz - 1;
4132          i > this_thr->th.th_task_state_top; i--, end--)
4133       end[0] = end[-1];
4134   }
4135   this_thr->th.th_task_state_memo_stack[this_thr->th.th_task_state_top + 1] =
4136       value;
4137 }
4138 
4139 // __kmp_task_team_setup:  Create a task_team for the current team, but use
4140 // an already created, unused one if it already exists.
4141 void __kmp_task_team_setup(kmp_info_t *this_thr, kmp_team_t *team, int always) {
4142   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
4143 
4144   // If this task_team hasn't been created yet, allocate it. It will be used in
4145   // the region after the next.
4146   // If it exists, it is the current task team and shouldn't be touched yet as
4147   // it may still be in use.
4148   if (team->t.t_task_team[this_thr->th.th_task_state] == NULL &&
4149       (always || team->t.t_nproc > 1)) {
4150     team->t.t_task_team[this_thr->th.th_task_state] =
4151         __kmp_allocate_task_team(this_thr, team);
4152     KA_TRACE(20, ("__kmp_task_team_setup: Primary T#%d created new task_team %p"
4153                   " for team %d at parity=%d\n",
4154                   __kmp_gtid_from_thread(this_thr),
4155                   team->t.t_task_team[this_thr->th.th_task_state], team->t.t_id,
4156                   this_thr->th.th_task_state));
4157   }
4158   if (this_thr->th.th_task_state == 1 && always && team->t.t_nproc == 1) {
4159     // fix task state stack to adjust for proxy and helper tasks
4160     KA_TRACE(20, ("__kmp_task_team_setup: Primary T#%d needs to shift stack"
4161                   " for team %d at parity=%d\n",
4162                   __kmp_gtid_from_thread(this_thr), team->t.t_id,
4163                   this_thr->th.th_task_state));
4164     __kmp_shift_task_state_stack(this_thr, this_thr->th.th_task_state);
4165   }
4166 
4167   // After threads exit the release, they will call sync, and then point to this
4168   // other task_team; make sure it is allocated and properly initialized. As
4169   // threads spin in the barrier release phase, they will continue to use the
4170   // previous task_team struct(above), until they receive the signal to stop
4171   // checking for tasks (they can't safely reference the kmp_team_t struct,
4172   // which could be reallocated by the primary thread). No task teams are formed
4173   // for serialized teams.
4174   if (team->t.t_nproc > 1) {
4175     int other_team = 1 - this_thr->th.th_task_state;
4176     KMP_DEBUG_ASSERT(other_team >= 0 && other_team < 2);
4177     if (team->t.t_task_team[other_team] == NULL) { // setup other team as well
4178       team->t.t_task_team[other_team] =
4179           __kmp_allocate_task_team(this_thr, team);
4180       KA_TRACE(20, ("__kmp_task_team_setup: Primary T#%d created second new "
4181                     "task_team %p for team %d at parity=%d\n",
4182                     __kmp_gtid_from_thread(this_thr),
4183                     team->t.t_task_team[other_team], team->t.t_id, other_team));
4184     } else { // Leave the old task team struct in place for the upcoming region;
4185       // adjust as needed
4186       kmp_task_team_t *task_team = team->t.t_task_team[other_team];
4187       if (!task_team->tt.tt_active ||
4188           team->t.t_nproc != task_team->tt.tt_nproc) {
4189         TCW_4(task_team->tt.tt_nproc, team->t.t_nproc);
4190         TCW_4(task_team->tt.tt_found_tasks, FALSE);
4191         TCW_4(task_team->tt.tt_found_proxy_tasks, FALSE);
4192         TCW_4(task_team->tt.tt_hidden_helper_task_encountered, FALSE);
4193         KMP_ATOMIC_ST_REL(&task_team->tt.tt_unfinished_threads,
4194                           team->t.t_nproc);
4195         TCW_4(task_team->tt.tt_active, TRUE);
4196       }
4197       // if team size has changed, the first thread to enable tasking will
4198       // realloc threads_data if necessary
4199       KA_TRACE(20, ("__kmp_task_team_setup: Primary T#%d reset next task_team "
4200                     "%p for team %d at parity=%d\n",
4201                     __kmp_gtid_from_thread(this_thr),
4202                     team->t.t_task_team[other_team], team->t.t_id, other_team));
4203     }
4204   }
4205 
4206   // For regular thread, task enabling should be called when the task is going
4207   // to be pushed to a dequeue. However, for the hidden helper thread, we need
4208   // it ahead of time so that some operations can be performed without race
4209   // condition.
4210   if (this_thr == __kmp_hidden_helper_main_thread) {
4211     for (int i = 0; i < 2; ++i) {
4212       kmp_task_team_t *task_team = team->t.t_task_team[i];
4213       if (KMP_TASKING_ENABLED(task_team)) {
4214         continue;
4215       }
4216       __kmp_enable_tasking(task_team, this_thr);
4217       for (int j = 0; j < task_team->tt.tt_nproc; ++j) {
4218         kmp_thread_data_t *thread_data = &task_team->tt.tt_threads_data[j];
4219         if (thread_data->td.td_deque == NULL) {
4220           __kmp_alloc_task_deque(__kmp_hidden_helper_threads[j], thread_data);
4221         }
4222       }
4223     }
4224   }
4225 }
4226 
4227 // __kmp_task_team_sync: Propagation of task team data from team to threads
4228 // which happens just after the release phase of a team barrier.  This may be
4229 // called by any thread, but only for teams with # threads > 1.
4230 void __kmp_task_team_sync(kmp_info_t *this_thr, kmp_team_t *team) {
4231   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
4232 
4233   // Toggle the th_task_state field, to switch which task_team this thread
4234   // refers to
4235   this_thr->th.th_task_state = (kmp_uint8)(1 - this_thr->th.th_task_state);
4236 
4237   // It is now safe to propagate the task team pointer from the team struct to
4238   // the current thread.
4239   TCW_PTR(this_thr->th.th_task_team,
4240           team->t.t_task_team[this_thr->th.th_task_state]);
4241   KA_TRACE(20,
4242            ("__kmp_task_team_sync: Thread T#%d task team switched to task_team "
4243             "%p from Team #%d (parity=%d)\n",
4244             __kmp_gtid_from_thread(this_thr), this_thr->th.th_task_team,
4245             team->t.t_id, this_thr->th.th_task_state));
4246 }
4247 
4248 // __kmp_task_team_wait: Primary thread waits for outstanding tasks after the
4249 // barrier gather phase. Only called by primary thread if #threads in team > 1
4250 // or if proxy tasks were created.
4251 //
4252 // wait is a flag that defaults to 1 (see kmp.h), but waiting can be turned off
4253 // by passing in 0 optionally as the last argument. When wait is zero, primary
4254 // thread does not wait for unfinished_threads to reach 0.
4255 void __kmp_task_team_wait(
4256     kmp_info_t *this_thr,
4257     kmp_team_t *team USE_ITT_BUILD_ARG(void *itt_sync_obj), int wait) {
4258   kmp_task_team_t *task_team = team->t.t_task_team[this_thr->th.th_task_state];
4259 
4260   KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
4261   KMP_DEBUG_ASSERT(task_team == this_thr->th.th_task_team);
4262 
4263   if ((task_team != NULL) && KMP_TASKING_ENABLED(task_team)) {
4264     if (wait) {
4265       KA_TRACE(20, ("__kmp_task_team_wait: Primary T#%d waiting for all tasks "
4266                     "(for unfinished_threads to reach 0) on task_team = %p\n",
4267                     __kmp_gtid_from_thread(this_thr), task_team));
4268       // Worker threads may have dropped through to release phase, but could
4269       // still be executing tasks. Wait here for tasks to complete. To avoid
4270       // memory contention, only primary thread checks termination condition.
4271       kmp_flag_32<false, false> flag(
4272           RCAST(std::atomic<kmp_uint32> *,
4273                 &task_team->tt.tt_unfinished_threads),
4274           0U);
4275       flag.wait(this_thr, TRUE USE_ITT_BUILD_ARG(itt_sync_obj));
4276     }
4277     // Deactivate the old task team, so that the worker threads will stop
4278     // referencing it while spinning.
4279     KA_TRACE(
4280         20,
4281         ("__kmp_task_team_wait: Primary T#%d deactivating task_team %p: "
4282          "setting active to false, setting local and team's pointer to NULL\n",
4283          __kmp_gtid_from_thread(this_thr), task_team));
4284     KMP_DEBUG_ASSERT(task_team->tt.tt_nproc > 1 ||
4285                      task_team->tt.tt_found_proxy_tasks == TRUE ||
4286                      task_team->tt.tt_hidden_helper_task_encountered == TRUE);
4287     TCW_SYNC_4(task_team->tt.tt_found_proxy_tasks, FALSE);
4288     TCW_SYNC_4(task_team->tt.tt_hidden_helper_task_encountered, FALSE);
4289     KMP_CHECK_UPDATE(task_team->tt.tt_untied_task_encountered, 0);
4290     TCW_SYNC_4(task_team->tt.tt_active, FALSE);
4291     KMP_MB();
4292 
4293     TCW_PTR(this_thr->th.th_task_team, NULL);
4294   }
4295 }
4296 
4297 // __kmp_tasking_barrier:
4298 // This routine is called only when __kmp_tasking_mode == tskm_extra_barrier.
4299 // Internal function to execute all tasks prior to a regular barrier or a join
4300 // barrier. It is a full barrier itself, which unfortunately turns regular
4301 // barriers into double barriers and join barriers into 1 1/2 barriers.
4302 void __kmp_tasking_barrier(kmp_team_t *team, kmp_info_t *thread, int gtid) {
4303   std::atomic<kmp_uint32> *spin = RCAST(
4304       std::atomic<kmp_uint32> *,
4305       &team->t.t_task_team[thread->th.th_task_state]->tt.tt_unfinished_threads);
4306   int flag = FALSE;
4307   KMP_DEBUG_ASSERT(__kmp_tasking_mode == tskm_extra_barrier);
4308 
4309 #if USE_ITT_BUILD
4310   KMP_FSYNC_SPIN_INIT(spin, NULL);
4311 #endif /* USE_ITT_BUILD */
4312   kmp_flag_32<false, false> spin_flag(spin, 0U);
4313   while (!spin_flag.execute_tasks(thread, gtid, TRUE,
4314                                   &flag USE_ITT_BUILD_ARG(NULL), 0)) {
4315 #if USE_ITT_BUILD
4316     // TODO: What about itt_sync_obj??
4317     KMP_FSYNC_SPIN_PREPARE(RCAST(void *, spin));
4318 #endif /* USE_ITT_BUILD */
4319 
4320     if (TCR_4(__kmp_global.g.g_done)) {
4321       if (__kmp_global.g.g_abort)
4322         __kmp_abort_thread();
4323       break;
4324     }
4325     KMP_YIELD(TRUE);
4326   }
4327 #if USE_ITT_BUILD
4328   KMP_FSYNC_SPIN_ACQUIRED(RCAST(void *, spin));
4329 #endif /* USE_ITT_BUILD */
4330 }
4331 
4332 // __kmp_give_task puts a task into a given thread queue if:
4333 //  - the queue for that thread was created
4334 //  - there's space in that queue
4335 // Because of this, __kmp_push_task needs to check if there's space after
4336 // getting the lock
4337 static bool __kmp_give_task(kmp_info_t *thread, kmp_int32 tid, kmp_task_t *task,
4338                             kmp_int32 pass) {
4339   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
4340   kmp_task_team_t *task_team = taskdata->td_task_team;
4341 
4342   KA_TRACE(20, ("__kmp_give_task: trying to give task %p to thread %d.\n",
4343                 taskdata, tid));
4344 
4345   // If task_team is NULL something went really bad...
4346   KMP_DEBUG_ASSERT(task_team != NULL);
4347 
4348   bool result = false;
4349   kmp_thread_data_t *thread_data = &task_team->tt.tt_threads_data[tid];
4350 
4351   if (thread_data->td.td_deque == NULL) {
4352     // There's no queue in this thread, go find another one
4353     // We're guaranteed that at least one thread has a queue
4354     KA_TRACE(30,
4355              ("__kmp_give_task: thread %d has no queue while giving task %p.\n",
4356               tid, taskdata));
4357     return result;
4358   }
4359 
4360   if (TCR_4(thread_data->td.td_deque_ntasks) >=
4361       TASK_DEQUE_SIZE(thread_data->td)) {
4362     KA_TRACE(
4363         30,
4364         ("__kmp_give_task: queue is full while giving task %p to thread %d.\n",
4365          taskdata, tid));
4366 
4367     // if this deque is bigger than the pass ratio give a chance to another
4368     // thread
4369     if (TASK_DEQUE_SIZE(thread_data->td) / INITIAL_TASK_DEQUE_SIZE >= pass)
4370       return result;
4371 
4372     __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
4373     if (TCR_4(thread_data->td.td_deque_ntasks) >=
4374         TASK_DEQUE_SIZE(thread_data->td)) {
4375       // expand deque to push the task which is not allowed to execute
4376       __kmp_realloc_task_deque(thread, thread_data);
4377     }
4378 
4379   } else {
4380 
4381     __kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
4382 
4383     if (TCR_4(thread_data->td.td_deque_ntasks) >=
4384         TASK_DEQUE_SIZE(thread_data->td)) {
4385       KA_TRACE(30, ("__kmp_give_task: queue is full while giving task %p to "
4386                     "thread %d.\n",
4387                     taskdata, tid));
4388 
4389       // if this deque is bigger than the pass ratio give a chance to another
4390       // thread
4391       if (TASK_DEQUE_SIZE(thread_data->td) / INITIAL_TASK_DEQUE_SIZE >= pass)
4392         goto release_and_exit;
4393 
4394       __kmp_realloc_task_deque(thread, thread_data);
4395     }
4396   }
4397 
4398   // lock is held here, and there is space in the deque
4399 
4400   thread_data->td.td_deque[thread_data->td.td_deque_tail] = taskdata;
4401   // Wrap index.
4402   thread_data->td.td_deque_tail =
4403       (thread_data->td.td_deque_tail + 1) & TASK_DEQUE_MASK(thread_data->td);
4404   TCW_4(thread_data->td.td_deque_ntasks,
4405         TCR_4(thread_data->td.td_deque_ntasks) + 1);
4406 
4407   result = true;
4408   KA_TRACE(30, ("__kmp_give_task: successfully gave task %p to thread %d.\n",
4409                 taskdata, tid));
4410 
4411 release_and_exit:
4412   __kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
4413 
4414   return result;
4415 }
4416 
4417 #define PROXY_TASK_FLAG 0x40000000
4418 /* The finish of the proxy tasks is divided in two pieces:
4419     - the top half is the one that can be done from a thread outside the team
4420     - the bottom half must be run from a thread within the team
4421 
4422    In order to run the bottom half the task gets queued back into one of the
4423    threads of the team. Once the td_incomplete_child_task counter of the parent
4424    is decremented the threads can leave the barriers. So, the bottom half needs
4425    to be queued before the counter is decremented. The top half is therefore
4426    divided in two parts:
4427     - things that can be run before queuing the bottom half
4428     - things that must be run after queuing the bottom half
4429 
4430    This creates a second race as the bottom half can free the task before the
4431    second top half is executed. To avoid this we use the
4432    td_incomplete_child_task of the proxy task to synchronize the top and bottom
4433    half. */
4434 static void __kmp_first_top_half_finish_proxy(kmp_taskdata_t *taskdata) {
4435   KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
4436   KMP_DEBUG_ASSERT(taskdata->td_flags.proxy == TASK_PROXY);
4437   KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 0);
4438   KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
4439 
4440   taskdata->td_flags.complete = 1; // mark the task as completed
4441 #if OMPX_TASKGRAPH
4442   taskdata->td_flags.onced = 1;
4443 #endif
4444 
4445   if (taskdata->td_taskgroup)
4446     KMP_ATOMIC_DEC(&taskdata->td_taskgroup->count);
4447 
4448   // Create an imaginary children for this task so the bottom half cannot
4449   // release the task before we have completed the second top half
4450   KMP_ATOMIC_OR(&taskdata->td_incomplete_child_tasks, PROXY_TASK_FLAG);
4451 }
4452 
4453 static void __kmp_second_top_half_finish_proxy(kmp_taskdata_t *taskdata) {
4454 #if KMP_DEBUG
4455   kmp_int32 children = 0;
4456   // Predecrement simulated by "- 1" calculation
4457   children = -1 +
4458 #endif
4459       KMP_ATOMIC_DEC(&taskdata->td_parent->td_incomplete_child_tasks);
4460   KMP_DEBUG_ASSERT(children >= 0);
4461 
4462   // Remove the imaginary children
4463   KMP_ATOMIC_AND(&taskdata->td_incomplete_child_tasks, ~PROXY_TASK_FLAG);
4464 }
4465 
4466 static void __kmp_bottom_half_finish_proxy(kmp_int32 gtid, kmp_task_t *ptask) {
4467   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(ptask);
4468   kmp_info_t *thread = __kmp_threads[gtid];
4469 
4470   KMP_DEBUG_ASSERT(taskdata->td_flags.proxy == TASK_PROXY);
4471   KMP_DEBUG_ASSERT(taskdata->td_flags.complete ==
4472                    1); // top half must run before bottom half
4473 
4474   // We need to wait to make sure the top half is finished
4475   // Spinning here should be ok as this should happen quickly
4476   while ((KMP_ATOMIC_LD_ACQ(&taskdata->td_incomplete_child_tasks) &
4477           PROXY_TASK_FLAG) > 0)
4478     ;
4479 
4480   __kmp_release_deps(gtid, taskdata);
4481   __kmp_free_task_and_ancestors(gtid, taskdata, thread);
4482 }
4483 
4484 /*!
4485 @ingroup TASKING
4486 @param gtid Global Thread ID of encountering thread
4487 @param ptask Task which execution is completed
4488 
4489 Execute the completion of a proxy task from a thread of that is part of the
4490 team. Run first and bottom halves directly.
4491 */
4492 void __kmpc_proxy_task_completed(kmp_int32 gtid, kmp_task_t *ptask) {
4493   KMP_DEBUG_ASSERT(ptask != NULL);
4494   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(ptask);
4495   KA_TRACE(
4496       10, ("__kmp_proxy_task_completed(enter): T#%d proxy task %p completing\n",
4497            gtid, taskdata));
4498   __kmp_assert_valid_gtid(gtid);
4499   KMP_DEBUG_ASSERT(taskdata->td_flags.proxy == TASK_PROXY);
4500 
4501   __kmp_first_top_half_finish_proxy(taskdata);
4502   __kmp_second_top_half_finish_proxy(taskdata);
4503   __kmp_bottom_half_finish_proxy(gtid, ptask);
4504 
4505   KA_TRACE(10,
4506            ("__kmp_proxy_task_completed(exit): T#%d proxy task %p completing\n",
4507             gtid, taskdata));
4508 }
4509 
4510 void __kmpc_give_task(kmp_task_t *ptask, kmp_int32 start = 0) {
4511   KMP_DEBUG_ASSERT(ptask != NULL);
4512   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(ptask);
4513 
4514   // Enqueue task to complete bottom half completion from a thread within the
4515   // corresponding team
4516   kmp_team_t *team = taskdata->td_team;
4517   kmp_int32 nthreads = team->t.t_nproc;
4518   kmp_info_t *thread;
4519 
4520   // This should be similar to start_k = __kmp_get_random( thread ) % nthreads
4521   // but we cannot use __kmp_get_random here
4522   kmp_int32 start_k = start % nthreads;
4523   kmp_int32 pass = 1;
4524   kmp_int32 k = start_k;
4525 
4526   do {
4527     // For now we're just linearly trying to find a thread
4528     thread = team->t.t_threads[k];
4529     k = (k + 1) % nthreads;
4530 
4531     // we did a full pass through all the threads
4532     if (k == start_k)
4533       pass = pass << 1;
4534 
4535   } while (!__kmp_give_task(thread, k, ptask, pass));
4536 
4537   if (__kmp_dflt_blocktime != KMP_MAX_BLOCKTIME && __kmp_wpolicy_passive) {
4538     // awake at least one thread to execute given task
4539     for (int i = 0; i < nthreads; ++i) {
4540       thread = team->t.t_threads[i];
4541       if (thread->th.th_sleep_loc != NULL) {
4542         __kmp_null_resume_wrapper(thread);
4543         break;
4544       }
4545     }
4546   }
4547 }
4548 
4549 /*!
4550 @ingroup TASKING
4551 @param ptask Task which execution is completed
4552 
4553 Execute the completion of a proxy task from a thread that could not belong to
4554 the team.
4555 */
4556 void __kmpc_proxy_task_completed_ooo(kmp_task_t *ptask) {
4557   KMP_DEBUG_ASSERT(ptask != NULL);
4558   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(ptask);
4559 
4560   KA_TRACE(
4561       10,
4562       ("__kmp_proxy_task_completed_ooo(enter): proxy task completing ooo %p\n",
4563        taskdata));
4564 
4565   KMP_DEBUG_ASSERT(taskdata->td_flags.proxy == TASK_PROXY);
4566 
4567   __kmp_first_top_half_finish_proxy(taskdata);
4568 
4569   __kmpc_give_task(ptask);
4570 
4571   __kmp_second_top_half_finish_proxy(taskdata);
4572 
4573   KA_TRACE(
4574       10,
4575       ("__kmp_proxy_task_completed_ooo(exit): proxy task completing ooo %p\n",
4576        taskdata));
4577 }
4578 
4579 kmp_event_t *__kmpc_task_allow_completion_event(ident_t *loc_ref, int gtid,
4580                                                 kmp_task_t *task) {
4581   kmp_taskdata_t *td = KMP_TASK_TO_TASKDATA(task);
4582   if (td->td_allow_completion_event.type == KMP_EVENT_UNINITIALIZED) {
4583     td->td_allow_completion_event.type = KMP_EVENT_ALLOW_COMPLETION;
4584     td->td_allow_completion_event.ed.task = task;
4585     __kmp_init_tas_lock(&td->td_allow_completion_event.lock);
4586   }
4587   return &td->td_allow_completion_event;
4588 }
4589 
4590 void __kmp_fulfill_event(kmp_event_t *event) {
4591   if (event->type == KMP_EVENT_ALLOW_COMPLETION) {
4592     kmp_task_t *ptask = event->ed.task;
4593     kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(ptask);
4594     bool detached = false;
4595     int gtid = __kmp_get_gtid();
4596 
4597     // The associated task might have completed or could be completing at this
4598     // point.
4599     // We need to take the lock to avoid races
4600     __kmp_acquire_tas_lock(&event->lock, gtid);
4601     if (taskdata->td_flags.proxy == TASK_PROXY) {
4602       detached = true;
4603     } else {
4604 #if OMPT_SUPPORT
4605       // The OMPT event must occur under mutual exclusion,
4606       // otherwise the tool might access ptask after free
4607       if (UNLIKELY(ompt_enabled.enabled))
4608         __ompt_task_finish(ptask, NULL, ompt_task_early_fulfill);
4609 #endif
4610     }
4611     event->type = KMP_EVENT_UNINITIALIZED;
4612     __kmp_release_tas_lock(&event->lock, gtid);
4613 
4614     if (detached) {
4615 #if OMPT_SUPPORT
4616       // We free ptask afterwards and know the task is finished,
4617       // so locking is not necessary
4618       if (UNLIKELY(ompt_enabled.enabled))
4619         __ompt_task_finish(ptask, NULL, ompt_task_late_fulfill);
4620 #endif
4621       // If the task detached complete the proxy task
4622       if (gtid >= 0) {
4623         kmp_team_t *team = taskdata->td_team;
4624         kmp_info_t *thread = __kmp_get_thread();
4625         if (thread->th.th_team == team) {
4626           __kmpc_proxy_task_completed(gtid, ptask);
4627           return;
4628         }
4629       }
4630 
4631       // fallback
4632       __kmpc_proxy_task_completed_ooo(ptask);
4633     }
4634   }
4635 }
4636 
4637 // __kmp_task_dup_alloc: Allocate the taskdata and make a copy of source task
4638 // for taskloop
4639 //
4640 // thread:   allocating thread
4641 // task_src: pointer to source task to be duplicated
4642 // taskloop_recur: used only when dealing with taskgraph,
4643 //      indicating whether we need to update task->td_task_id
4644 // returns:  a pointer to the allocated kmp_task_t structure (task).
4645 kmp_task_t *__kmp_task_dup_alloc(kmp_info_t *thread, kmp_task_t *task_src
4646 #if OMPX_TASKGRAPH
4647                                  , int taskloop_recur
4648 #endif
4649 ) {
4650   kmp_task_t *task;
4651   kmp_taskdata_t *taskdata;
4652   kmp_taskdata_t *taskdata_src = KMP_TASK_TO_TASKDATA(task_src);
4653   kmp_taskdata_t *parent_task = taskdata_src->td_parent; // same parent task
4654   size_t shareds_offset;
4655   size_t task_size;
4656 
4657   KA_TRACE(10, ("__kmp_task_dup_alloc(enter): Th %p, source task %p\n", thread,
4658                 task_src));
4659   KMP_DEBUG_ASSERT(taskdata_src->td_flags.proxy ==
4660                    TASK_FULL); // it should not be proxy task
4661   KMP_DEBUG_ASSERT(taskdata_src->td_flags.tasktype == TASK_EXPLICIT);
4662   task_size = taskdata_src->td_size_alloc;
4663 
4664   // Allocate a kmp_taskdata_t block and a kmp_task_t block.
4665   KA_TRACE(30, ("__kmp_task_dup_alloc: Th %p, malloc size %ld\n", thread,
4666                 task_size));
4667 #if USE_FAST_MEMORY
4668   taskdata = (kmp_taskdata_t *)__kmp_fast_allocate(thread, task_size);
4669 #else
4670   taskdata = (kmp_taskdata_t *)__kmp_thread_malloc(thread, task_size);
4671 #endif /* USE_FAST_MEMORY */
4672   KMP_MEMCPY(taskdata, taskdata_src, task_size);
4673 
4674   task = KMP_TASKDATA_TO_TASK(taskdata);
4675 
4676   // Initialize new task (only specific fields not affected by memcpy)
4677 #if OMPX_TASKGRAPH
4678   if (!taskdata->is_taskgraph || taskloop_recur)
4679     taskdata->td_task_id = KMP_GEN_TASK_ID();
4680   else if (taskdata->is_taskgraph &&
4681            __kmp_tdg_is_recording(taskdata_src->tdg->tdg_status))
4682     taskdata->td_task_id = KMP_ATOMIC_INC(&__kmp_tdg_task_id);
4683 #else
4684   taskdata->td_task_id = KMP_GEN_TASK_ID();
4685 #endif
4686   if (task->shareds != NULL) { // need setup shareds pointer
4687     shareds_offset = (char *)task_src->shareds - (char *)taskdata_src;
4688     task->shareds = &((char *)taskdata)[shareds_offset];
4689     KMP_DEBUG_ASSERT((((kmp_uintptr_t)task->shareds) & (sizeof(void *) - 1)) ==
4690                      0);
4691   }
4692   taskdata->td_alloc_thread = thread;
4693   taskdata->td_parent = parent_task;
4694   // task inherits the taskgroup from the parent task
4695   taskdata->td_taskgroup = parent_task->td_taskgroup;
4696   // tied task needs to initialize the td_last_tied at creation,
4697   // untied one does this when it is scheduled for execution
4698   if (taskdata->td_flags.tiedness == TASK_TIED)
4699     taskdata->td_last_tied = taskdata;
4700 
4701   // Only need to keep track of child task counts if team parallel and tasking
4702   // not serialized
4703   if (!(taskdata->td_flags.team_serial || taskdata->td_flags.tasking_ser)) {
4704     KMP_ATOMIC_INC(&parent_task->td_incomplete_child_tasks);
4705     if (parent_task->td_taskgroup)
4706       KMP_ATOMIC_INC(&parent_task->td_taskgroup->count);
4707     // Only need to keep track of allocated child tasks for explicit tasks since
4708     // implicit not deallocated
4709     if (taskdata->td_parent->td_flags.tasktype == TASK_EXPLICIT)
4710       KMP_ATOMIC_INC(&taskdata->td_parent->td_allocated_child_tasks);
4711   }
4712 
4713   KA_TRACE(20,
4714            ("__kmp_task_dup_alloc(exit): Th %p, created task %p, parent=%p\n",
4715             thread, taskdata, taskdata->td_parent));
4716 #if OMPT_SUPPORT
4717   if (UNLIKELY(ompt_enabled.enabled))
4718     __ompt_task_init(taskdata, thread->th.th_info.ds.ds_gtid);
4719 #endif
4720   return task;
4721 }
4722 
4723 // Routine optionally generated by the compiler for setting the lastprivate flag
4724 // and calling needed constructors for private/firstprivate objects
4725 // (used to form taskloop tasks from pattern task)
4726 // Parameters: dest task, src task, lastprivate flag.
4727 typedef void (*p_task_dup_t)(kmp_task_t *, kmp_task_t *, kmp_int32);
4728 
4729 KMP_BUILD_ASSERT(sizeof(long) == 4 || sizeof(long) == 8);
4730 
4731 // class to encapsulate manipulating loop bounds in a taskloop task.
4732 // this abstracts away the Intel vs GOMP taskloop interface for setting/getting
4733 // the loop bound variables.
4734 class kmp_taskloop_bounds_t {
4735   kmp_task_t *task;
4736   const kmp_taskdata_t *taskdata;
4737   size_t lower_offset;
4738   size_t upper_offset;
4739 
4740 public:
4741   kmp_taskloop_bounds_t(kmp_task_t *_task, kmp_uint64 *lb, kmp_uint64 *ub)
4742       : task(_task), taskdata(KMP_TASK_TO_TASKDATA(task)),
4743         lower_offset((char *)lb - (char *)task),
4744         upper_offset((char *)ub - (char *)task) {
4745     KMP_DEBUG_ASSERT((char *)lb > (char *)_task);
4746     KMP_DEBUG_ASSERT((char *)ub > (char *)_task);
4747   }
4748   kmp_taskloop_bounds_t(kmp_task_t *_task, const kmp_taskloop_bounds_t &bounds)
4749       : task(_task), taskdata(KMP_TASK_TO_TASKDATA(_task)),
4750         lower_offset(bounds.lower_offset), upper_offset(bounds.upper_offset) {}
4751   size_t get_lower_offset() const { return lower_offset; }
4752   size_t get_upper_offset() const { return upper_offset; }
4753   kmp_uint64 get_lb() const {
4754     kmp_int64 retval;
4755 #if defined(KMP_GOMP_COMPAT)
4756     // Intel task just returns the lower bound normally
4757     if (!taskdata->td_flags.native) {
4758       retval = *(kmp_int64 *)((char *)task + lower_offset);
4759     } else {
4760       // GOMP task has to take into account the sizeof(long)
4761       if (taskdata->td_size_loop_bounds == 4) {
4762         kmp_int32 *lb = RCAST(kmp_int32 *, task->shareds);
4763         retval = (kmp_int64)*lb;
4764       } else {
4765         kmp_int64 *lb = RCAST(kmp_int64 *, task->shareds);
4766         retval = (kmp_int64)*lb;
4767       }
4768     }
4769 #else
4770     (void)taskdata;
4771     retval = *(kmp_int64 *)((char *)task + lower_offset);
4772 #endif // defined(KMP_GOMP_COMPAT)
4773     return retval;
4774   }
4775   kmp_uint64 get_ub() const {
4776     kmp_int64 retval;
4777 #if defined(KMP_GOMP_COMPAT)
4778     // Intel task just returns the upper bound normally
4779     if (!taskdata->td_flags.native) {
4780       retval = *(kmp_int64 *)((char *)task + upper_offset);
4781     } else {
4782       // GOMP task has to take into account the sizeof(long)
4783       if (taskdata->td_size_loop_bounds == 4) {
4784         kmp_int32 *ub = RCAST(kmp_int32 *, task->shareds) + 1;
4785         retval = (kmp_int64)*ub;
4786       } else {
4787         kmp_int64 *ub = RCAST(kmp_int64 *, task->shareds) + 1;
4788         retval = (kmp_int64)*ub;
4789       }
4790     }
4791 #else
4792     retval = *(kmp_int64 *)((char *)task + upper_offset);
4793 #endif // defined(KMP_GOMP_COMPAT)
4794     return retval;
4795   }
4796   void set_lb(kmp_uint64 lb) {
4797 #if defined(KMP_GOMP_COMPAT)
4798     // Intel task just sets the lower bound normally
4799     if (!taskdata->td_flags.native) {
4800       *(kmp_uint64 *)((char *)task + lower_offset) = lb;
4801     } else {
4802       // GOMP task has to take into account the sizeof(long)
4803       if (taskdata->td_size_loop_bounds == 4) {
4804         kmp_uint32 *lower = RCAST(kmp_uint32 *, task->shareds);
4805         *lower = (kmp_uint32)lb;
4806       } else {
4807         kmp_uint64 *lower = RCAST(kmp_uint64 *, task->shareds);
4808         *lower = (kmp_uint64)lb;
4809       }
4810     }
4811 #else
4812     *(kmp_uint64 *)((char *)task + lower_offset) = lb;
4813 #endif // defined(KMP_GOMP_COMPAT)
4814   }
4815   void set_ub(kmp_uint64 ub) {
4816 #if defined(KMP_GOMP_COMPAT)
4817     // Intel task just sets the upper bound normally
4818     if (!taskdata->td_flags.native) {
4819       *(kmp_uint64 *)((char *)task + upper_offset) = ub;
4820     } else {
4821       // GOMP task has to take into account the sizeof(long)
4822       if (taskdata->td_size_loop_bounds == 4) {
4823         kmp_uint32 *upper = RCAST(kmp_uint32 *, task->shareds) + 1;
4824         *upper = (kmp_uint32)ub;
4825       } else {
4826         kmp_uint64 *upper = RCAST(kmp_uint64 *, task->shareds) + 1;
4827         *upper = (kmp_uint64)ub;
4828       }
4829     }
4830 #else
4831     *(kmp_uint64 *)((char *)task + upper_offset) = ub;
4832 #endif // defined(KMP_GOMP_COMPAT)
4833   }
4834 };
4835 
4836 // __kmp_taskloop_linear: Start tasks of the taskloop linearly
4837 //
4838 // loc        Source location information
4839 // gtid       Global thread ID
4840 // task       Pattern task, exposes the loop iteration range
4841 // lb         Pointer to loop lower bound in task structure
4842 // ub         Pointer to loop upper bound in task structure
4843 // st         Loop stride
4844 // ub_glob    Global upper bound (used for lastprivate check)
4845 // num_tasks  Number of tasks to execute
4846 // grainsize  Number of loop iterations per task
4847 // extras     Number of chunks with grainsize+1 iterations
4848 // last_chunk Reduction of grainsize for last task
4849 // tc         Iterations count
4850 // task_dup   Tasks duplication routine
4851 // codeptr_ra Return address for OMPT events
4852 void __kmp_taskloop_linear(ident_t *loc, int gtid, kmp_task_t *task,
4853                            kmp_uint64 *lb, kmp_uint64 *ub, kmp_int64 st,
4854                            kmp_uint64 ub_glob, kmp_uint64 num_tasks,
4855                            kmp_uint64 grainsize, kmp_uint64 extras,
4856                            kmp_int64 last_chunk, kmp_uint64 tc,
4857 #if OMPT_SUPPORT
4858                            void *codeptr_ra,
4859 #endif
4860                            void *task_dup) {
4861   KMP_COUNT_BLOCK(OMP_TASKLOOP);
4862   KMP_TIME_PARTITIONED_BLOCK(OMP_taskloop_scheduling);
4863   p_task_dup_t ptask_dup = (p_task_dup_t)task_dup;
4864   // compiler provides global bounds here
4865   kmp_taskloop_bounds_t task_bounds(task, lb, ub);
4866   kmp_uint64 lower = task_bounds.get_lb();
4867   kmp_uint64 upper = task_bounds.get_ub();
4868   kmp_uint64 i;
4869   kmp_info_t *thread = __kmp_threads[gtid];
4870   kmp_taskdata_t *current_task = thread->th.th_current_task;
4871   kmp_task_t *next_task;
4872   kmp_int32 lastpriv = 0;
4873 
4874   KMP_DEBUG_ASSERT(tc == num_tasks * grainsize +
4875                              (last_chunk < 0 ? last_chunk : extras));
4876   KMP_DEBUG_ASSERT(num_tasks > extras);
4877   KMP_DEBUG_ASSERT(num_tasks > 0);
4878   KA_TRACE(20, ("__kmp_taskloop_linear: T#%d: %lld tasks, grainsize %lld, "
4879                 "extras %lld, last_chunk %lld, i=%lld,%lld(%d)%lld, dup %p\n",
4880                 gtid, num_tasks, grainsize, extras, last_chunk, lower, upper,
4881                 ub_glob, st, task_dup));
4882 
4883   // Launch num_tasks tasks, assign grainsize iterations each task
4884   for (i = 0; i < num_tasks; ++i) {
4885     kmp_uint64 chunk_minus_1;
4886     if (extras == 0) {
4887       chunk_minus_1 = grainsize - 1;
4888     } else {
4889       chunk_minus_1 = grainsize;
4890       --extras; // first extras iterations get bigger chunk (grainsize+1)
4891     }
4892     upper = lower + st * chunk_minus_1;
4893     if (upper > *ub) {
4894       upper = *ub;
4895     }
4896     if (i == num_tasks - 1) {
4897       // schedule the last task, set lastprivate flag if needed
4898       if (st == 1) { // most common case
4899         KMP_DEBUG_ASSERT(upper == *ub);
4900         if (upper == ub_glob)
4901           lastpriv = 1;
4902       } else if (st > 0) { // positive loop stride
4903         KMP_DEBUG_ASSERT((kmp_uint64)st > *ub - upper);
4904         if ((kmp_uint64)st > ub_glob - upper)
4905           lastpriv = 1;
4906       } else { // negative loop stride
4907         KMP_DEBUG_ASSERT(upper + st < *ub);
4908         if (upper - ub_glob < (kmp_uint64)(-st))
4909           lastpriv = 1;
4910       }
4911     }
4912 
4913 #if OMPX_TASKGRAPH
4914     next_task = __kmp_task_dup_alloc(thread, task, /* taskloop_recur */ 0);
4915 #else
4916     next_task = __kmp_task_dup_alloc(thread, task); // allocate new task
4917 #endif
4918 
4919     kmp_taskdata_t *next_taskdata = KMP_TASK_TO_TASKDATA(next_task);
4920     kmp_taskloop_bounds_t next_task_bounds =
4921         kmp_taskloop_bounds_t(next_task, task_bounds);
4922 
4923     // adjust task-specific bounds
4924     next_task_bounds.set_lb(lower);
4925     if (next_taskdata->td_flags.native) {
4926       next_task_bounds.set_ub(upper + (st > 0 ? 1 : -1));
4927     } else {
4928       next_task_bounds.set_ub(upper);
4929     }
4930     if (ptask_dup != NULL) // set lastprivate flag, construct firstprivates,
4931                            // etc.
4932       ptask_dup(next_task, task, lastpriv);
4933     KA_TRACE(40,
4934              ("__kmp_taskloop_linear: T#%d; task #%llu: task %p: lower %lld, "
4935               "upper %lld stride %lld, (offsets %p %p)\n",
4936               gtid, i, next_task, lower, upper, st,
4937               next_task_bounds.get_lower_offset(),
4938               next_task_bounds.get_upper_offset()));
4939 #if OMPT_SUPPORT
4940     __kmp_omp_taskloop_task(NULL, gtid, next_task,
4941                             codeptr_ra); // schedule new task
4942 #if OMPT_OPTIONAL
4943     if (ompt_enabled.ompt_callback_dispatch) {
4944       OMPT_GET_DISPATCH_CHUNK(next_taskdata->ompt_task_info.dispatch_chunk,
4945                               lower, upper, st);
4946     }
4947 #endif // OMPT_OPTIONAL
4948 #else
4949     __kmp_omp_task(gtid, next_task, true); // schedule new task
4950 #endif
4951     lower = upper + st; // adjust lower bound for the next iteration
4952   }
4953   // free the pattern task and exit
4954   __kmp_task_start(gtid, task, current_task); // make internal bookkeeping
4955   // do not execute the pattern task, just do internal bookkeeping
4956   __kmp_task_finish<false>(gtid, task, current_task);
4957 }
4958 
4959 // Structure to keep taskloop parameters for auxiliary task
4960 // kept in the shareds of the task structure.
4961 typedef struct __taskloop_params {
4962   kmp_task_t *task;
4963   kmp_uint64 *lb;
4964   kmp_uint64 *ub;
4965   void *task_dup;
4966   kmp_int64 st;
4967   kmp_uint64 ub_glob;
4968   kmp_uint64 num_tasks;
4969   kmp_uint64 grainsize;
4970   kmp_uint64 extras;
4971   kmp_int64 last_chunk;
4972   kmp_uint64 tc;
4973   kmp_uint64 num_t_min;
4974 #if OMPT_SUPPORT
4975   void *codeptr_ra;
4976 #endif
4977 } __taskloop_params_t;
4978 
4979 void __kmp_taskloop_recur(ident_t *, int, kmp_task_t *, kmp_uint64 *,
4980                           kmp_uint64 *, kmp_int64, kmp_uint64, kmp_uint64,
4981                           kmp_uint64, kmp_uint64, kmp_int64, kmp_uint64,
4982                           kmp_uint64,
4983 #if OMPT_SUPPORT
4984                           void *,
4985 #endif
4986                           void *);
4987 
4988 // Execute part of the taskloop submitted as a task.
4989 int __kmp_taskloop_task(int gtid, void *ptask) {
4990   __taskloop_params_t *p =
4991       (__taskloop_params_t *)((kmp_task_t *)ptask)->shareds;
4992   kmp_task_t *task = p->task;
4993   kmp_uint64 *lb = p->lb;
4994   kmp_uint64 *ub = p->ub;
4995   void *task_dup = p->task_dup;
4996   //  p_task_dup_t ptask_dup = (p_task_dup_t)task_dup;
4997   kmp_int64 st = p->st;
4998   kmp_uint64 ub_glob = p->ub_glob;
4999   kmp_uint64 num_tasks = p->num_tasks;
5000   kmp_uint64 grainsize = p->grainsize;
5001   kmp_uint64 extras = p->extras;
5002   kmp_int64 last_chunk = p->last_chunk;
5003   kmp_uint64 tc = p->tc;
5004   kmp_uint64 num_t_min = p->num_t_min;
5005 #if OMPT_SUPPORT
5006   void *codeptr_ra = p->codeptr_ra;
5007 #endif
5008 #if KMP_DEBUG
5009   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
5010   KMP_DEBUG_ASSERT(task != NULL);
5011   KA_TRACE(20,
5012            ("__kmp_taskloop_task: T#%d, task %p: %lld tasks, grainsize"
5013             " %lld, extras %lld, last_chunk %lld, i=%lld,%lld(%d), dup %p\n",
5014             gtid, taskdata, num_tasks, grainsize, extras, last_chunk, *lb, *ub,
5015             st, task_dup));
5016 #endif
5017   KMP_DEBUG_ASSERT(num_tasks * 2 + 1 > num_t_min);
5018   if (num_tasks > num_t_min)
5019     __kmp_taskloop_recur(NULL, gtid, task, lb, ub, st, ub_glob, num_tasks,
5020                          grainsize, extras, last_chunk, tc, num_t_min,
5021 #if OMPT_SUPPORT
5022                          codeptr_ra,
5023 #endif
5024                          task_dup);
5025   else
5026     __kmp_taskloop_linear(NULL, gtid, task, lb, ub, st, ub_glob, num_tasks,
5027                           grainsize, extras, last_chunk, tc,
5028 #if OMPT_SUPPORT
5029                           codeptr_ra,
5030 #endif
5031                           task_dup);
5032 
5033   KA_TRACE(40, ("__kmp_taskloop_task(exit): T#%d\n", gtid));
5034   return 0;
5035 }
5036 
5037 // Schedule part of the taskloop as a task,
5038 // execute the rest of the taskloop.
5039 //
5040 // loc        Source location information
5041 // gtid       Global thread ID
5042 // task       Pattern task, exposes the loop iteration range
5043 // lb         Pointer to loop lower bound in task structure
5044 // ub         Pointer to loop upper bound in task structure
5045 // st         Loop stride
5046 // ub_glob    Global upper bound (used for lastprivate check)
5047 // num_tasks  Number of tasks to execute
5048 // grainsize  Number of loop iterations per task
5049 // extras     Number of chunks with grainsize+1 iterations
5050 // last_chunk Reduction of grainsize for last task
5051 // tc         Iterations count
5052 // num_t_min  Threshold to launch tasks recursively
5053 // task_dup   Tasks duplication routine
5054 // codeptr_ra Return address for OMPT events
5055 void __kmp_taskloop_recur(ident_t *loc, int gtid, kmp_task_t *task,
5056                           kmp_uint64 *lb, kmp_uint64 *ub, kmp_int64 st,
5057                           kmp_uint64 ub_glob, kmp_uint64 num_tasks,
5058                           kmp_uint64 grainsize, kmp_uint64 extras,
5059                           kmp_int64 last_chunk, kmp_uint64 tc,
5060                           kmp_uint64 num_t_min,
5061 #if OMPT_SUPPORT
5062                           void *codeptr_ra,
5063 #endif
5064                           void *task_dup) {
5065   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
5066   KMP_DEBUG_ASSERT(task != NULL);
5067   KMP_DEBUG_ASSERT(num_tasks > num_t_min);
5068   KA_TRACE(20,
5069            ("__kmp_taskloop_recur: T#%d, task %p: %lld tasks, grainsize"
5070             " %lld, extras %lld, last_chunk %lld, i=%lld,%lld(%d), dup %p\n",
5071             gtid, taskdata, num_tasks, grainsize, extras, last_chunk, *lb, *ub,
5072             st, task_dup));
5073   p_task_dup_t ptask_dup = (p_task_dup_t)task_dup;
5074   kmp_uint64 lower = *lb;
5075   kmp_info_t *thread = __kmp_threads[gtid];
5076   //  kmp_taskdata_t *current_task = thread->th.th_current_task;
5077   kmp_task_t *next_task;
5078   size_t lower_offset =
5079       (char *)lb - (char *)task; // remember offset of lb in the task structure
5080   size_t upper_offset =
5081       (char *)ub - (char *)task; // remember offset of ub in the task structure
5082 
5083   KMP_DEBUG_ASSERT(tc == num_tasks * grainsize +
5084                              (last_chunk < 0 ? last_chunk : extras));
5085   KMP_DEBUG_ASSERT(num_tasks > extras);
5086   KMP_DEBUG_ASSERT(num_tasks > 0);
5087 
5088   // split the loop in two halves
5089   kmp_uint64 lb1, ub0, tc0, tc1, ext0, ext1;
5090   kmp_int64 last_chunk0 = 0, last_chunk1 = 0;
5091   kmp_uint64 gr_size0 = grainsize;
5092   kmp_uint64 n_tsk0 = num_tasks >> 1; // num_tasks/2 to execute
5093   kmp_uint64 n_tsk1 = num_tasks - n_tsk0; // to schedule as a task
5094   if (last_chunk < 0) {
5095     ext0 = ext1 = 0;
5096     last_chunk1 = last_chunk;
5097     tc0 = grainsize * n_tsk0;
5098     tc1 = tc - tc0;
5099   } else if (n_tsk0 <= extras) {
5100     gr_size0++; // integrate extras into grainsize
5101     ext0 = 0; // no extra iters in 1st half
5102     ext1 = extras - n_tsk0; // remaining extras
5103     tc0 = gr_size0 * n_tsk0;
5104     tc1 = tc - tc0;
5105   } else { // n_tsk0 > extras
5106     ext1 = 0; // no extra iters in 2nd half
5107     ext0 = extras;
5108     tc1 = grainsize * n_tsk1;
5109     tc0 = tc - tc1;
5110   }
5111   ub0 = lower + st * (tc0 - 1);
5112   lb1 = ub0 + st;
5113 
5114   // create pattern task for 2nd half of the loop
5115 #if OMPX_TASKGRAPH
5116   next_task = __kmp_task_dup_alloc(thread, task,
5117                                    /* taskloop_recur */ 1);
5118 #else
5119   next_task = __kmp_task_dup_alloc(thread, task); // duplicate the task
5120 #endif
5121   // adjust lower bound (upper bound is not changed) for the 2nd half
5122   *(kmp_uint64 *)((char *)next_task + lower_offset) = lb1;
5123   if (ptask_dup != NULL) // construct firstprivates, etc.
5124     ptask_dup(next_task, task, 0);
5125   *ub = ub0; // adjust upper bound for the 1st half
5126 
5127   // create auxiliary task for 2nd half of the loop
5128   // make sure new task has same parent task as the pattern task
5129   kmp_taskdata_t *current_task = thread->th.th_current_task;
5130   thread->th.th_current_task = taskdata->td_parent;
5131   kmp_task_t *new_task =
5132       __kmpc_omp_task_alloc(loc, gtid, 1, 3 * sizeof(void *),
5133                             sizeof(__taskloop_params_t), &__kmp_taskloop_task);
5134   // restore current task
5135   thread->th.th_current_task = current_task;
5136   __taskloop_params_t *p = (__taskloop_params_t *)new_task->shareds;
5137   p->task = next_task;
5138   p->lb = (kmp_uint64 *)((char *)next_task + lower_offset);
5139   p->ub = (kmp_uint64 *)((char *)next_task + upper_offset);
5140   p->task_dup = task_dup;
5141   p->st = st;
5142   p->ub_glob = ub_glob;
5143   p->num_tasks = n_tsk1;
5144   p->grainsize = grainsize;
5145   p->extras = ext1;
5146   p->last_chunk = last_chunk1;
5147   p->tc = tc1;
5148   p->num_t_min = num_t_min;
5149 #if OMPT_SUPPORT
5150   p->codeptr_ra = codeptr_ra;
5151 #endif
5152 
5153 #if OMPX_TASKGRAPH
5154   kmp_taskdata_t *new_task_data = KMP_TASK_TO_TASKDATA(new_task);
5155   new_task_data->tdg = taskdata->tdg;
5156   new_task_data->is_taskgraph = 0;
5157 #endif
5158 
5159 #if OMPT_SUPPORT
5160   // schedule new task with correct return address for OMPT events
5161   __kmp_omp_taskloop_task(NULL, gtid, new_task, codeptr_ra);
5162 #else
5163   __kmp_omp_task(gtid, new_task, true); // schedule new task
5164 #endif
5165 
5166   // execute the 1st half of current subrange
5167   if (n_tsk0 > num_t_min)
5168     __kmp_taskloop_recur(loc, gtid, task, lb, ub, st, ub_glob, n_tsk0, gr_size0,
5169                          ext0, last_chunk0, tc0, num_t_min,
5170 #if OMPT_SUPPORT
5171                          codeptr_ra,
5172 #endif
5173                          task_dup);
5174   else
5175     __kmp_taskloop_linear(loc, gtid, task, lb, ub, st, ub_glob, n_tsk0,
5176                           gr_size0, ext0, last_chunk0, tc0,
5177 #if OMPT_SUPPORT
5178                           codeptr_ra,
5179 #endif
5180                           task_dup);
5181 
5182   KA_TRACE(40, ("__kmp_taskloop_recur(exit): T#%d\n", gtid));
5183 }
5184 
5185 static void __kmp_taskloop(ident_t *loc, int gtid, kmp_task_t *task, int if_val,
5186                            kmp_uint64 *lb, kmp_uint64 *ub, kmp_int64 st,
5187                            int nogroup, int sched, kmp_uint64 grainsize,
5188                            int modifier, void *task_dup) {
5189   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
5190   KMP_DEBUG_ASSERT(task != NULL);
5191   if (nogroup == 0) {
5192 #if OMPT_SUPPORT && OMPT_OPTIONAL
5193     OMPT_STORE_RETURN_ADDRESS(gtid);
5194 #endif
5195     __kmpc_taskgroup(loc, gtid);
5196   }
5197 
5198 #if OMPX_TASKGRAPH
5199   KMP_ATOMIC_DEC(&__kmp_tdg_task_id);
5200 #endif
5201   // =========================================================================
5202   // calculate loop parameters
5203   kmp_taskloop_bounds_t task_bounds(task, lb, ub);
5204   kmp_uint64 tc;
5205   // compiler provides global bounds here
5206   kmp_uint64 lower = task_bounds.get_lb();
5207   kmp_uint64 upper = task_bounds.get_ub();
5208   kmp_uint64 ub_glob = upper; // global upper used to calc lastprivate flag
5209   kmp_uint64 num_tasks = 0, extras = 0;
5210   kmp_int64 last_chunk =
5211       0; // reduce grainsize of last task by last_chunk in strict mode
5212   kmp_uint64 num_tasks_min = __kmp_taskloop_min_tasks;
5213   kmp_info_t *thread = __kmp_threads[gtid];
5214   kmp_taskdata_t *current_task = thread->th.th_current_task;
5215 
5216   KA_TRACE(20, ("__kmp_taskloop: T#%d, task %p, lb %lld, ub %lld, st %lld, "
5217                 "grain %llu(%d, %d), dup %p\n",
5218                 gtid, taskdata, lower, upper, st, grainsize, sched, modifier,
5219                 task_dup));
5220 
5221   // compute trip count
5222   if (st == 1) { // most common case
5223     tc = upper - lower + 1;
5224   } else if (st < 0) {
5225     tc = (lower - upper) / (-st) + 1;
5226   } else { // st > 0
5227     tc = (upper - lower) / st + 1;
5228   }
5229   if (tc == 0) {
5230     KA_TRACE(20, ("__kmp_taskloop(exit): T#%d zero-trip loop\n", gtid));
5231     // free the pattern task and exit
5232     __kmp_task_start(gtid, task, current_task);
5233     // do not execute anything for zero-trip loop
5234     __kmp_task_finish<false>(gtid, task, current_task);
5235     return;
5236   }
5237 
5238 #if OMPT_SUPPORT && OMPT_OPTIONAL
5239   ompt_team_info_t *team_info = __ompt_get_teaminfo(0, NULL);
5240   ompt_task_info_t *task_info = __ompt_get_task_info_object(0);
5241   if (ompt_enabled.ompt_callback_work) {
5242     ompt_callbacks.ompt_callback(ompt_callback_work)(
5243         ompt_work_taskloop, ompt_scope_begin, &(team_info->parallel_data),
5244         &(task_info->task_data), tc, OMPT_GET_RETURN_ADDRESS(0));
5245   }
5246 #endif
5247 
5248   if (num_tasks_min == 0)
5249     // TODO: can we choose better default heuristic?
5250     num_tasks_min =
5251         KMP_MIN(thread->th.th_team_nproc * 10, INITIAL_TASK_DEQUE_SIZE);
5252 
5253   // compute num_tasks/grainsize based on the input provided
5254   switch (sched) {
5255   case 0: // no schedule clause specified, we can choose the default
5256     // let's try to schedule (team_size*10) tasks
5257     grainsize = thread->th.th_team_nproc * 10;
5258     KMP_FALLTHROUGH();
5259   case 2: // num_tasks provided
5260     if (grainsize > tc) {
5261       num_tasks = tc; // too big num_tasks requested, adjust values
5262       grainsize = 1;
5263       extras = 0;
5264     } else {
5265       num_tasks = grainsize;
5266       grainsize = tc / num_tasks;
5267       extras = tc % num_tasks;
5268     }
5269     break;
5270   case 1: // grainsize provided
5271     if (grainsize > tc) {
5272       num_tasks = 1;
5273       grainsize = tc; // too big grainsize requested, adjust values
5274       extras = 0;
5275     } else {
5276       if (modifier) {
5277         num_tasks = (tc + grainsize - 1) / grainsize;
5278         last_chunk = tc - (num_tasks * grainsize);
5279         extras = 0;
5280       } else {
5281         num_tasks = tc / grainsize;
5282         // adjust grainsize for balanced distribution of iterations
5283         grainsize = tc / num_tasks;
5284         extras = tc % num_tasks;
5285       }
5286     }
5287     break;
5288   default:
5289     KMP_ASSERT2(0, "unknown scheduling of taskloop");
5290   }
5291 
5292   KMP_DEBUG_ASSERT(tc == num_tasks * grainsize +
5293                              (last_chunk < 0 ? last_chunk : extras));
5294   KMP_DEBUG_ASSERT(num_tasks > extras);
5295   KMP_DEBUG_ASSERT(num_tasks > 0);
5296   // =========================================================================
5297 
5298   // check if clause value first
5299   // Also require GOMP_taskloop to reduce to linear (taskdata->td_flags.native)
5300   if (if_val == 0) { // if(0) specified, mark task as serial
5301     taskdata->td_flags.task_serial = 1;
5302     taskdata->td_flags.tiedness = TASK_TIED; // AC: serial task cannot be untied
5303     // always start serial tasks linearly
5304     __kmp_taskloop_linear(loc, gtid, task, lb, ub, st, ub_glob, num_tasks,
5305                           grainsize, extras, last_chunk, tc,
5306 #if OMPT_SUPPORT
5307                           OMPT_GET_RETURN_ADDRESS(0),
5308 #endif
5309                           task_dup);
5310     // !taskdata->td_flags.native => currently force linear spawning of tasks
5311     // for GOMP_taskloop
5312   } else if (num_tasks > num_tasks_min && !taskdata->td_flags.native) {
5313     KA_TRACE(20, ("__kmp_taskloop: T#%d, go recursive: tc %llu, #tasks %llu"
5314                   "(%lld), grain %llu, extras %llu, last_chunk %lld\n",
5315                   gtid, tc, num_tasks, num_tasks_min, grainsize, extras,
5316                   last_chunk));
5317     __kmp_taskloop_recur(loc, gtid, task, lb, ub, st, ub_glob, num_tasks,
5318                          grainsize, extras, last_chunk, tc, num_tasks_min,
5319 #if OMPT_SUPPORT
5320                          OMPT_GET_RETURN_ADDRESS(0),
5321 #endif
5322                          task_dup);
5323   } else {
5324     KA_TRACE(20, ("__kmp_taskloop: T#%d, go linear: tc %llu, #tasks %llu"
5325                   "(%lld), grain %llu, extras %llu, last_chunk %lld\n",
5326                   gtid, tc, num_tasks, num_tasks_min, grainsize, extras,
5327                   last_chunk));
5328     __kmp_taskloop_linear(loc, gtid, task, lb, ub, st, ub_glob, num_tasks,
5329                           grainsize, extras, last_chunk, tc,
5330 #if OMPT_SUPPORT
5331                           OMPT_GET_RETURN_ADDRESS(0),
5332 #endif
5333                           task_dup);
5334   }
5335 
5336 #if OMPT_SUPPORT && OMPT_OPTIONAL
5337   if (ompt_enabled.ompt_callback_work) {
5338     ompt_callbacks.ompt_callback(ompt_callback_work)(
5339         ompt_work_taskloop, ompt_scope_end, &(team_info->parallel_data),
5340         &(task_info->task_data), tc, OMPT_GET_RETURN_ADDRESS(0));
5341   }
5342 #endif
5343 
5344   if (nogroup == 0) {
5345 #if OMPT_SUPPORT && OMPT_OPTIONAL
5346     OMPT_STORE_RETURN_ADDRESS(gtid);
5347 #endif
5348     __kmpc_end_taskgroup(loc, gtid);
5349   }
5350   KA_TRACE(20, ("__kmp_taskloop(exit): T#%d\n", gtid));
5351 }
5352 
5353 /*!
5354 @ingroup TASKING
5355 @param loc       Source location information
5356 @param gtid      Global thread ID
5357 @param task      Task structure
5358 @param if_val    Value of the if clause
5359 @param lb        Pointer to loop lower bound in task structure
5360 @param ub        Pointer to loop upper bound in task structure
5361 @param st        Loop stride
5362 @param nogroup   Flag, 1 if nogroup clause specified, 0 otherwise
5363 @param sched     Schedule specified 0/1/2 for none/grainsize/num_tasks
5364 @param grainsize Schedule value if specified
5365 @param task_dup  Tasks duplication routine
5366 
5367 Execute the taskloop construct.
5368 */
5369 void __kmpc_taskloop(ident_t *loc, int gtid, kmp_task_t *task, int if_val,
5370                      kmp_uint64 *lb, kmp_uint64 *ub, kmp_int64 st, int nogroup,
5371                      int sched, kmp_uint64 grainsize, void *task_dup) {
5372   __kmp_assert_valid_gtid(gtid);
5373   KA_TRACE(20, ("__kmpc_taskloop(enter): T#%d\n", gtid));
5374   __kmp_taskloop(loc, gtid, task, if_val, lb, ub, st, nogroup, sched, grainsize,
5375                  0, task_dup);
5376   KA_TRACE(20, ("__kmpc_taskloop(exit): T#%d\n", gtid));
5377 }
5378 
5379 /*!
5380 @ingroup TASKING
5381 @param loc       Source location information
5382 @param gtid      Global thread ID
5383 @param task      Task structure
5384 @param if_val    Value of the if clause
5385 @param lb        Pointer to loop lower bound in task structure
5386 @param ub        Pointer to loop upper bound in task structure
5387 @param st        Loop stride
5388 @param nogroup   Flag, 1 if nogroup clause specified, 0 otherwise
5389 @param sched     Schedule specified 0/1/2 for none/grainsize/num_tasks
5390 @param grainsize Schedule value if specified
5391 @param modifier  Modifier 'strict' for sched, 1 if present, 0 otherwise
5392 @param task_dup  Tasks duplication routine
5393 
5394 Execute the taskloop construct.
5395 */
5396 void __kmpc_taskloop_5(ident_t *loc, int gtid, kmp_task_t *task, int if_val,
5397                        kmp_uint64 *lb, kmp_uint64 *ub, kmp_int64 st,
5398                        int nogroup, int sched, kmp_uint64 grainsize,
5399                        int modifier, void *task_dup) {
5400   __kmp_assert_valid_gtid(gtid);
5401   KA_TRACE(20, ("__kmpc_taskloop_5(enter): T#%d\n", gtid));
5402   __kmp_taskloop(loc, gtid, task, if_val, lb, ub, st, nogroup, sched, grainsize,
5403                  modifier, task_dup);
5404   KA_TRACE(20, ("__kmpc_taskloop_5(exit): T#%d\n", gtid));
5405 }
5406 
5407 /*!
5408 @ingroup TASKING
5409 @param gtid Global Thread ID of current thread
5410 @return Returns a pointer to the thread's current task async handle. If no task
5411 is present or gtid is invalid, returns NULL.
5412 
5413 Acqurires a pointer to the target async handle from the current task.
5414 */
5415 void **__kmpc_omp_get_target_async_handle_ptr(kmp_int32 gtid) {
5416   if (gtid == KMP_GTID_DNE)
5417     return NULL;
5418 
5419   kmp_info_t *thread = __kmp_thread_from_gtid(gtid);
5420   kmp_taskdata_t *taskdata = thread->th.th_current_task;
5421 
5422   if (!taskdata)
5423     return NULL;
5424 
5425   return &taskdata->td_target_data.async_handle;
5426 }
5427 
5428 /*!
5429 @ingroup TASKING
5430 @param gtid Global Thread ID of current thread
5431 @return Returns TRUE if the current task being executed of the given thread has
5432 a task team allocated to it. Otherwise, returns FALSE.
5433 
5434 Checks if the current thread has a task team.
5435 */
5436 bool __kmpc_omp_has_task_team(kmp_int32 gtid) {
5437   if (gtid == KMP_GTID_DNE)
5438     return FALSE;
5439 
5440   kmp_info_t *thread = __kmp_thread_from_gtid(gtid);
5441   kmp_taskdata_t *taskdata = thread->th.th_current_task;
5442 
5443   if (!taskdata)
5444     return FALSE;
5445 
5446   return taskdata->td_task_team != NULL;
5447 }
5448 
5449 #if OMPX_TASKGRAPH
5450 // __kmp_find_tdg: identify a TDG through its ID
5451 // gtid:   Global Thread ID
5452 // tdg_id: ID of the TDG
5453 // returns: If a TDG corresponding to this ID is found and not
5454 // its initial state, return the pointer to it, otherwise nullptr
5455 static kmp_tdg_info_t *__kmp_find_tdg(kmp_int32 tdg_id) {
5456   kmp_tdg_info_t *res = nullptr;
5457   if (__kmp_max_tdgs == 0)
5458     return res;
5459 
5460   if (__kmp_global_tdgs == NULL)
5461     __kmp_global_tdgs = (kmp_tdg_info_t **)__kmp_allocate(
5462         sizeof(kmp_tdg_info_t *) * __kmp_max_tdgs);
5463 
5464   if ((__kmp_global_tdgs[tdg_id]) &&
5465       (__kmp_global_tdgs[tdg_id]->tdg_status != KMP_TDG_NONE))
5466     res = __kmp_global_tdgs[tdg_id];
5467   return res;
5468 }
5469 
5470 // __kmp_print_tdg_dot: prints the TDG to a dot file
5471 // tdg:    ID of the TDG
5472 void __kmp_print_tdg_dot(kmp_tdg_info_t *tdg) {
5473   kmp_int32 tdg_id = tdg->tdg_id;
5474   KA_TRACE(10, ("__kmp_print_tdg_dot(enter): T#%d tdg_id=%d \n", gtid, tdg_id));
5475 
5476   char file_name[20];
5477   sprintf(file_name, "tdg_%d.dot", tdg_id);
5478   kmp_safe_raii_file_t tdg_file(file_name, "w");
5479 
5480   kmp_int32 num_tasks = KMP_ATOMIC_LD_RLX(&tdg->num_tasks);
5481   fprintf(tdg_file,
5482           "digraph TDG {\n"
5483           "   compound=true\n"
5484           "   subgraph cluster {\n"
5485           "      label=TDG_%d\n",
5486           tdg_id);
5487   for (kmp_int32 i = 0; i < num_tasks; i++) {
5488     fprintf(tdg_file, "      %d[style=bold]\n", i);
5489   }
5490   fprintf(tdg_file, "   }\n");
5491   for (kmp_int32 i = 0; i < num_tasks; i++) {
5492     kmp_int32 nsuccessors = tdg->record_map[i].nsuccessors;
5493     kmp_int32 *successors = tdg->record_map[i].successors;
5494     if (nsuccessors > 0) {
5495       for (kmp_int32 j = 0; j < nsuccessors; j++)
5496         fprintf(tdg_file, "   %d -> %d \n", i, successors[j]);
5497     }
5498   }
5499   fprintf(tdg_file, "}");
5500   KA_TRACE(10, ("__kmp_print_tdg_dot(exit): T#%d tdg_id=%d \n", gtid, tdg_id));
5501 }
5502 
5503 // __kmp_start_record: launch the execution of a previous
5504 // recorded TDG
5505 // gtid:   Global Thread ID
5506 // tdg:    ID of the TDG
5507 void __kmp_exec_tdg(kmp_int32 gtid, kmp_tdg_info_t *tdg) {
5508   KMP_DEBUG_ASSERT(tdg->tdg_status == KMP_TDG_READY);
5509   KA_TRACE(10, ("__kmp_exec_tdg(enter): T#%d tdg_id=%d num_roots=%d\n", gtid,
5510                 tdg->tdg_id, tdg->num_roots));
5511   kmp_node_info_t *this_record_map = tdg->record_map;
5512   kmp_int32 *this_root_tasks = tdg->root_tasks;
5513   kmp_int32 this_num_roots = tdg->num_roots;
5514   kmp_int32 this_num_tasks = KMP_ATOMIC_LD_RLX(&tdg->num_tasks);
5515 
5516   kmp_info_t *thread = __kmp_threads[gtid];
5517   kmp_taskdata_t *parent_task = thread->th.th_current_task;
5518 
5519   if (tdg->rec_taskred_data) {
5520     __kmpc_taskred_init(gtid, tdg->rec_num_taskred, tdg->rec_taskred_data);
5521   }
5522 
5523   for (kmp_int32 j = 0; j < this_num_tasks; j++) {
5524     kmp_taskdata_t *td = KMP_TASK_TO_TASKDATA(this_record_map[j].task);
5525 
5526     td->td_parent = parent_task;
5527     this_record_map[j].parent_task = parent_task;
5528 
5529     kmp_taskgroup_t *parent_taskgroup =
5530         this_record_map[j].parent_task->td_taskgroup;
5531 
5532     KMP_ATOMIC_ST_RLX(&this_record_map[j].npredecessors_counter,
5533                       this_record_map[j].npredecessors);
5534     KMP_ATOMIC_INC(&this_record_map[j].parent_task->td_incomplete_child_tasks);
5535 
5536     if (parent_taskgroup) {
5537       KMP_ATOMIC_INC(&parent_taskgroup->count);
5538       // The taskgroup is different so we must update it
5539       td->td_taskgroup = parent_taskgroup;
5540     } else if (td->td_taskgroup != nullptr) {
5541       // If the parent doesnt have a taskgroup, remove it from the task
5542       td->td_taskgroup = nullptr;
5543     }
5544     if (this_record_map[j].parent_task->td_flags.tasktype == TASK_EXPLICIT)
5545       KMP_ATOMIC_INC(&this_record_map[j].parent_task->td_allocated_child_tasks);
5546   }
5547 
5548   for (kmp_int32 j = 0; j < this_num_roots; ++j) {
5549     __kmp_omp_task(gtid, this_record_map[this_root_tasks[j]].task, true);
5550   }
5551   KA_TRACE(10, ("__kmp_exec_tdg(exit): T#%d tdg_id=%d num_roots=%d\n", gtid,
5552                 tdg->tdg_id, tdg->num_roots));
5553 }
5554 
5555 // __kmp_start_record: set up a TDG structure and turn the
5556 // recording flag to true
5557 // gtid:        Global Thread ID of the encountering thread
5558 // input_flags: Flags associated with the TDG
5559 // tdg_id:      ID of the TDG to record
5560 static inline void __kmp_start_record(kmp_int32 gtid,
5561                                       kmp_taskgraph_flags_t *flags,
5562                                       kmp_int32 tdg_id) {
5563   kmp_tdg_info_t *tdg =
5564       (kmp_tdg_info_t *)__kmp_allocate(sizeof(kmp_tdg_info_t));
5565   __kmp_global_tdgs[__kmp_curr_tdg_idx] = tdg;
5566   // Initializing the TDG structure
5567   tdg->tdg_id = tdg_id;
5568   tdg->map_size = INIT_MAPSIZE;
5569   tdg->num_roots = -1;
5570   tdg->root_tasks = nullptr;
5571   tdg->tdg_status = KMP_TDG_RECORDING;
5572   tdg->rec_num_taskred = 0;
5573   tdg->rec_taskred_data = nullptr;
5574   KMP_ATOMIC_ST_RLX(&tdg->num_tasks, 0);
5575 
5576   // Initializing the list of nodes in this TDG
5577   kmp_node_info_t *this_record_map =
5578       (kmp_node_info_t *)__kmp_allocate(INIT_MAPSIZE * sizeof(kmp_node_info_t));
5579   for (kmp_int32 i = 0; i < INIT_MAPSIZE; i++) {
5580     kmp_int32 *successorsList =
5581         (kmp_int32 *)__kmp_allocate(__kmp_successors_size * sizeof(kmp_int32));
5582     this_record_map[i].task = nullptr;
5583     this_record_map[i].successors = successorsList;
5584     this_record_map[i].nsuccessors = 0;
5585     this_record_map[i].npredecessors = 0;
5586     this_record_map[i].successors_size = __kmp_successors_size;
5587     KMP_ATOMIC_ST_RLX(&this_record_map[i].npredecessors_counter, 0);
5588   }
5589 
5590   __kmp_global_tdgs[__kmp_curr_tdg_idx]->record_map = this_record_map;
5591 }
5592 
5593 // __kmpc_start_record_task: Wrapper around __kmp_start_record to mark
5594 // the beginning of the record process of a task region
5595 // loc_ref:     Location of TDG, not used yet
5596 // gtid:        Global Thread ID of the encountering thread
5597 // input_flags: Flags associated with the TDG
5598 // tdg_id:      ID of the TDG to record, for now, incremental integer
5599 // returns:     1 if we record, otherwise, 0
5600 kmp_int32 __kmpc_start_record_task(ident_t *loc_ref, kmp_int32 gtid,
5601                                    kmp_int32 input_flags, kmp_int32 tdg_id) {
5602 
5603   kmp_int32 res;
5604   kmp_taskgraph_flags_t *flags = (kmp_taskgraph_flags_t *)&input_flags;
5605   KA_TRACE(10,
5606            ("__kmpc_start_record_task(enter): T#%d loc=%p flags=%d tdg_id=%d\n",
5607             gtid, loc_ref, input_flags, tdg_id));
5608 
5609   if (__kmp_max_tdgs == 0) {
5610     KA_TRACE(
5611         10,
5612         ("__kmpc_start_record_task(abandon): T#%d loc=%p flags=%d tdg_id = %d, "
5613          "__kmp_max_tdgs = 0\n",
5614          gtid, loc_ref, input_flags, tdg_id));
5615     return 1;
5616   }
5617 
5618   __kmpc_taskgroup(loc_ref, gtid);
5619   if (kmp_tdg_info_t *tdg = __kmp_find_tdg(tdg_id)) {
5620     // TODO: use re_record flag
5621     __kmp_exec_tdg(gtid, tdg);
5622     res = 0;
5623   } else {
5624     __kmp_curr_tdg_idx = tdg_id;
5625     KMP_DEBUG_ASSERT(__kmp_curr_tdg_idx < __kmp_max_tdgs);
5626     __kmp_start_record(gtid, flags, tdg_id);
5627     __kmp_num_tdg++;
5628     res = 1;
5629   }
5630   KA_TRACE(10, ("__kmpc_start_record_task(exit): T#%d TDG %d starts to %s\n",
5631                 gtid, tdg_id, res ? "record" : "execute"));
5632   return res;
5633 }
5634 
5635 // __kmp_end_record: set up a TDG after recording it
5636 // gtid:   Global thread ID
5637 // tdg:    Pointer to the TDG
5638 void __kmp_end_record(kmp_int32 gtid, kmp_tdg_info_t *tdg) {
5639   // Store roots
5640   kmp_node_info_t *this_record_map = tdg->record_map;
5641   kmp_int32 this_num_tasks = KMP_ATOMIC_LD_RLX(&tdg->num_tasks);
5642   kmp_int32 *this_root_tasks =
5643       (kmp_int32 *)__kmp_allocate(this_num_tasks * sizeof(kmp_int32));
5644   kmp_int32 this_map_size = tdg->map_size;
5645   kmp_int32 this_num_roots = 0;
5646   kmp_info_t *thread = __kmp_threads[gtid];
5647 
5648   for (kmp_int32 i = 0; i < this_num_tasks; i++) {
5649     if (this_record_map[i].npredecessors == 0) {
5650       this_root_tasks[this_num_roots++] = i;
5651     }
5652   }
5653 
5654   // Update with roots info and mapsize
5655   tdg->map_size = this_map_size;
5656   tdg->num_roots = this_num_roots;
5657   tdg->root_tasks = this_root_tasks;
5658   KMP_DEBUG_ASSERT(tdg->tdg_status == KMP_TDG_RECORDING);
5659   tdg->tdg_status = KMP_TDG_READY;
5660 
5661   if (thread->th.th_current_task->td_dephash) {
5662     __kmp_dephash_free(thread, thread->th.th_current_task->td_dephash);
5663     thread->th.th_current_task->td_dephash = NULL;
5664   }
5665 
5666   // Reset predecessor counter
5667   for (kmp_int32 i = 0; i < this_num_tasks; i++) {
5668     KMP_ATOMIC_ST_RLX(&this_record_map[i].npredecessors_counter,
5669                       this_record_map[i].npredecessors);
5670   }
5671   KMP_ATOMIC_ST_RLX(&__kmp_tdg_task_id, 0);
5672 
5673   if (__kmp_tdg_dot)
5674     __kmp_print_tdg_dot(tdg);
5675 }
5676 
5677 // __kmpc_end_record_task: wrapper around __kmp_end_record to mark
5678 // the end of recording phase
5679 //
5680 // loc_ref:      Source location information
5681 // gtid:         Global thread ID
5682 // input_flags:  Flags attached to the graph
5683 // tdg_id:       ID of the TDG just finished recording
5684 void __kmpc_end_record_task(ident_t *loc_ref, kmp_int32 gtid,
5685                             kmp_int32 input_flags, kmp_int32 tdg_id) {
5686   kmp_tdg_info_t *tdg = __kmp_find_tdg(tdg_id);
5687 
5688   KA_TRACE(10, ("__kmpc_end_record_task(enter): T#%d loc=%p finishes recording"
5689                 " tdg=%d with flags=%d\n",
5690                 gtid, loc_ref, tdg_id, input_flags));
5691   if (__kmp_max_tdgs) {
5692     // TODO: use input_flags->nowait
5693     __kmpc_end_taskgroup(loc_ref, gtid);
5694     if (__kmp_tdg_is_recording(tdg->tdg_status))
5695       __kmp_end_record(gtid, tdg);
5696   }
5697   KA_TRACE(10, ("__kmpc_end_record_task(exit): T#%d loc=%p finished recording"
5698                 " tdg=%d, its status is now READY\n",
5699                 gtid, loc_ref, tdg_id));
5700 }
5701 #endif
5702