history.cc

   1 #include <inttypes.h>
   2 #include "history.h"
   3 #include "action.h"
   4 #include "funcnode.h"
   5 #include "funcinst.h"
   6 #include "common.h"
   7 #include "concretepredicate.h"
   8 #include "waitobj.h"
   9
  10 #include "model.h"
  11 #include "execution.h"
  12 #include "newfuzzer.h"
  13
  14 /** @brief Constructor */
  15 ModelHistory::ModelHistory() :
  16         func_counter(1),        /* function id starts with 1 */
  17         func_map(),
  18         func_map_rev(),
  19         func_nodes()
  20 {
  21         /* The following are snapshot data structures */
  22         write_history = new HashTable<void *, value_set_t *, uintptr_t, 0>();
  23         loc_rd_func_nodes_map = new HashTable<void *, SnapVector<FuncNode *> *, uintptr_t, 0>();
  24         loc_wr_func_nodes_map = new HashTable<void *, SnapVector<FuncNode *> *, uintptr_t, 0>();
  25         loc_waiting_writes_map = new HashTable<void *, SnapVector<ConcretePredicate *> *, uintptr_t, 0>();
  26         thrd_func_act_lists = new SnapVector< SnapList<action_list_t *> *>();
  27         thrd_func_list = new SnapVector<func_id_list_t>();
  28         thrd_last_entered_func = new SnapVector<uint32_t>();
  29         thrd_waiting_write = new SnapVector<ConcretePredicate *>();
  30         thrd_wait_obj = new SnapVector<WaitObj *>();
  31         func_inst_act_maps = new HashTable<uint32_t, SnapVector<inst_act_map_t *> *, int, 0>(128);
  32 }
  33
  34 ModelHistory::~ModelHistory()
  35 {
  36         // TODO: complete deconstructor; maybe not needed
  37         for (uint i = 0;i < thrd_wait_obj->size();i++)
  38                 delete (*thrd_wait_obj)[i];
  39 }
  40
  41 void ModelHistory::enter_function(const uint32_t func_id, thread_id_t tid)
  42 {
  43         //model_print("thread %d entering func %d\n", tid, func_id);
  44         uint id = id_to_int(tid);
  45
  46         if ( thrd_func_list->size() <= id ) {
  47                 uint oldsize = thrd_func_list->size();
  48                 thrd_func_list->resize( id + 1 );
  49                 thrd_func_act_lists->resize( id + 1 );
  50
  51                 for (uint i = oldsize;i < id + 1;i++) {
  52                         // push 0 as a dummy function id to a void seg fault
  53                         new (&(*thrd_func_list)[i]) func_id_list_t();
  54                         (*thrd_func_list)[i].push_back(0);
  55
  56                         (*thrd_func_act_lists)[i] = new SnapList<action_list_t *>();
  57                         thrd_last_entered_func->push_back(0);
  58                 }
  59         }
  60
  61         SnapList<action_list_t *> * func_act_lists = (*thrd_func_act_lists)[id];
  62         func_act_lists->push_back( new action_list_t() );
  63
  64         uint32_t last_entered_func_id = (*thrd_last_entered_func)[id];
  65         (*thrd_last_entered_func)[id] = func_id;
  66         (*thrd_func_list)[id].push_back(func_id);
  67
  68         if ( func_nodes.size() <= func_id )
  69                 resize_func_nodes( func_id + 1 );
  70
  71         FuncNode * func_node = func_nodes[func_id];
  72         func_node->init_predicate_tree_position(tid);
  73         func_node->init_inst_act_map(tid);
  74
  75         /* Add edges between FuncNodes */
  76         if (last_entered_func_id != 0) {
  77                 FuncNode * last_func_node = func_nodes[last_entered_func_id];
  78                 last_func_node->add_out_edge(func_node);
  79         }
  80
  81         /* Monitor the statuses of threads waiting for tid */
  82         // monitor_waiting_thread(func_id, tid);
  83 }
  84
  85 /* @param func_id a non-zero value */
  86 void ModelHistory::exit_function(const uint32_t func_id, thread_id_t tid)
  87 {
  88         uint32_t id = id_to_int(tid);
  89
  90         SnapList<action_list_t *> * func_act_lists = (*thrd_func_act_lists)[id];
  91         uint32_t last_func_id = (*thrd_func_list)[id].back();
  92
  93         if (last_func_id == func_id) {
  94                 FuncNode * func_node = func_nodes[func_id];
  95                 func_node->set_predicate_tree_position(tid, NULL);
  96                 func_node->reset_inst_act_map(tid);
  97
  98                 action_list_t * curr_act_list = func_act_lists->back();
  99
 100                 /* defer the processing of curr_act_list until the function has exits a few times
 101                  * (currently twice) so that more information can be gathered to infer nullity predicates.
 102                  */
 103                 func_node->incr_exit_count();
 104                 if (func_node->get_exit_count() >= 2) {
 105                         SnapList<action_list_t *> * action_list_buffer = func_node->get_action_list_buffer();
 106                         while (action_list_buffer->size() > 0) {
 107                                 action_list_t * act_list = action_list_buffer->back();
 108                                 action_list_buffer->pop_back();
 109                                 func_node->update_tree(act_list);
 110                         }
 111
 112                         func_node->update_tree(curr_act_list);
 113                 } else
 114                         func_node->get_action_list_buffer()->push_front(curr_act_list);
 115
 116                 (*thrd_func_list)[id].pop_back();
 117                 func_act_lists->pop_back();
 118         } else {
 119                 model_print("trying to exit with a wrong function id\n");
 120                 model_print("--- last_func: %d, func_id: %d\n", last_func_id, func_id);
 121         }
 122         //model_print("thread %d exiting func %d\n", tid, func_id);
 123 }
 124
 125 void ModelHistory::resize_func_nodes(uint32_t new_size)
 126 {
 127         uint32_t old_size = func_nodes.size();
 128
 129         if ( old_size < new_size )
 130                 func_nodes.resize(new_size);
 131
 132         for (uint32_t id = old_size;id < new_size;id++) {
 133                 const char * func_name = func_map_rev[id];
 134                 FuncNode * func_node = new FuncNode(this);
 135                 func_node->set_func_id(id);
 136                 func_node->set_func_name(func_name);
 137                 func_nodes[id] = func_node;
 138         }
 139 }
 140
 141 void ModelHistory::process_action(ModelAction *act, thread_id_t tid)
 142 {
 143         uint32_t thread_id = id_to_int(tid);
 144         /* Return if thread tid has not entered any function that contains atomics */
 145         if ( thrd_func_list->size() <= thread_id )
 146                 return;
 147
 148         /* Monitor the statuses of threads waiting for tid */
 149         // monitor_waiting_thread_counter(tid);
 150
 151         /* Every write action should be processed, including
 152          * nonatomic writes (which have no position) */
 153         if (act->is_write()) {
 154                 void * location = act->get_location();
 155                 uint64_t value = act->get_write_value();
 156                 update_write_history(location, value);
 157
 158                 /* Notify FuncNodes that may read from this location */
 159                 SnapVector<FuncNode *> * func_node_list = getRdFuncNodes(location);
 160                 for (uint i = 0;i < func_node_list->size();i++) {
 161                         FuncNode * func_node = (*func_node_list)[i];
 162                         func_node->add_to_val_loc_map(value, location);
 163                 }
 164
 165                 // check_waiting_write(act);
 166         }
 167
 168         uint32_t func_id = (*thrd_func_list)[thread_id].back();
 169
 170         /* The following does not care about actions that are not inside
 171          * any function that contains atomics or actions without a position */
 172         if (func_id == 0 || act->get_position() == NULL)
 173                 return;
 174
 175         SnapList<action_list_t *> * func_act_lists = (*thrd_func_act_lists)[thread_id];
 176
 177         /* The list of actions that thread tid has taken in its current function */
 178         action_list_t * curr_act_list = func_act_lists->back();
 179
 180         if (skip_action(act, curr_act_list))
 181                 return;
 182
 183         /* Add to curr_inst_list */
 184         act->setFuncActRef(curr_act_list->add_back(act));
 185
 186         FuncNode * func_node = func_nodes[func_id];
 187         func_node->add_inst(act);
 188
 189         if (act->is_read()) {
 190                 func_node->update_inst_act_map(tid, act);
 191
 192                 Fuzzer * fuzzer = model->get_execution()->getFuzzer();
 193                 Predicate * selected_branch = ((NewFuzzer *)fuzzer)->get_selected_child_branch(tid);
 194                 func_node->set_predicate_tree_position(tid, selected_branch);
 195         }
 196
 197         if (act->is_write()) {
 198                 Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
 199                 FuncInst * curr_inst = func_node->get_inst(act);
 200
 201                 if (curr_pred) {
 202                         // Follow child
 203                         curr_pred = curr_pred->follow_write_child(curr_inst);
 204                 }
 205                 func_node->set_predicate_tree_position(tid, curr_pred);
 206         }
 207 }
 208
 209 /* Return the FuncNode given its func_id  */
 210 FuncNode * ModelHistory::get_func_node(uint32_t func_id)
 211 {
 212         if (func_id == 0)
 213                 return NULL;
 214
 215         // This node has not been added to func_nodes
 216         if (func_nodes.size() <= func_id)
 217                 return NULL;
 218
 219         return func_nodes[func_id];
 220 }
 221
 222 /* Return the current FuncNode when given a thread id */
 223 FuncNode * ModelHistory::get_curr_func_node(thread_id_t tid)
 224 {
 225         int thread_id = id_to_int(tid);
 226         uint32_t func_id = (*thrd_func_list)[thread_id].back();
 227
 228         if (func_id != 0) {
 229                 return func_nodes[func_id];
 230         }
 231
 232         return NULL;
 233 }
 234
 235 void ModelHistory::update_write_history(void * location, uint64_t write_val)
 236 {
 237         value_set_t * write_set = write_history->get(location);
 238
 239         if (write_set == NULL) {
 240                 write_set = new value_set_t();
 241                 write_history->put(location, write_set);
 242         }
 243
 244         write_set->add(write_val);
 245 }
 246
 247 void ModelHistory::update_loc_rd_func_nodes_map(void * location, FuncNode * node)
 248 {
 249         SnapVector<FuncNode *> * func_node_list = getRdFuncNodes(location);
 250         func_node_list->push_back(node);
 251 }
 252
 253 void ModelHistory::update_loc_wr_func_nodes_map(void * location, FuncNode * node)
 254 {
 255         SnapVector<FuncNode *> * func_node_list = getWrFuncNodes(location);
 256         func_node_list->push_back(node);
 257 }
 258
 259 SnapVector<FuncNode *> * ModelHistory::getRdFuncNodes(void * location)
 260 {
 261         SnapVector<FuncNode *> * func_node_list = loc_rd_func_nodes_map->get(location);
 262         if (func_node_list == NULL) {
 263                 func_node_list = new SnapVector<FuncNode *>();
 264                 loc_rd_func_nodes_map->put(location, func_node_list);
 265         }
 266
 267         return func_node_list;
 268 }
 269
 270 SnapVector<FuncNode *> * ModelHistory::getWrFuncNodes(void * location)
 271 {
 272         SnapVector<FuncNode *> * func_node_list = loc_wr_func_nodes_map->get(location);
 273         if (func_node_list == NULL) {
 274                 func_node_list = new SnapVector<FuncNode *>();
 275                 loc_wr_func_nodes_map->put(location, func_node_list);
 276         }
 277
 278         return func_node_list;
 279 }
 280
 281 /* When a thread is paused by Fuzzer, keep track of the condition it is waiting for */
 282 void ModelHistory::add_waiting_write(ConcretePredicate * concrete)
 283 {
 284         void * location = concrete->get_location();
 285         SnapVector<ConcretePredicate *> * waiting_conditions = loc_waiting_writes_map->get(location);
 286         if (waiting_conditions == NULL) {
 287                 waiting_conditions = new SnapVector<ConcretePredicate *>();
 288                 loc_waiting_writes_map->put(location, waiting_conditions);
 289         }
 290
 291         /* waiting_conditions should not have duplications */
 292         waiting_conditions->push_back(concrete);
 293
 294         int thread_id = id_to_int(concrete->get_tid());
 295         if (thrd_waiting_write->size() <= (uint) thread_id) {
 296                 thrd_waiting_write->resize(thread_id + 1);
 297         }
 298
 299         (*thrd_waiting_write)[thread_id] = concrete;
 300 }
 301
 302 void ModelHistory::remove_waiting_write(thread_id_t tid)
 303 {
 304         ConcretePredicate * concrete = (*thrd_waiting_write)[ id_to_int(tid) ];
 305         void * location = concrete->get_location();
 306         SnapVector<ConcretePredicate *> * concrete_preds = loc_waiting_writes_map->get(location);
 307
 308         /* Linear search should be fine because presumably not many ConcretePredicates
 309          * are at the same memory location */
 310         for (uint i = 0;i < concrete_preds->size();i++) {
 311                 ConcretePredicate * current = (*concrete_preds)[i];
 312                 if (concrete == current) {
 313                         (*concrete_preds)[i] = concrete_preds->back();
 314                         concrete_preds->pop_back();
 315                         break;
 316                 }
 317         }
 318
 319         int thread_id = id_to_int( concrete->get_tid() );
 320         (*thrd_waiting_write)[thread_id] = NULL;
 321         delete concrete;
 322 }
 323
 324 /* Check if any other thread is waiting for this write action. If so, "notify" them */
 325 void ModelHistory::check_waiting_write(ModelAction * write_act)
 326 {
 327         void * location = write_act->get_location();
 328         uint64_t value = write_act->get_write_value();
 329         SnapVector<ConcretePredicate *> * concrete_preds = loc_waiting_writes_map->get(location);
 330         if (concrete_preds == NULL)
 331                 return;
 332
 333         uint index = 0;
 334         while (index < concrete_preds->size()) {
 335                 ConcretePredicate * concrete_pred = (*concrete_preds)[index];
 336                 SnapVector<struct concrete_pred_expr> * concrete_exprs = concrete_pred->getExpressions();
 337                 bool satisfy_predicate = true;
 338                 /* Check if the written value satisfies every predicate expression */
 339                 for (uint i = 0;i < concrete_exprs->size();i++) {
 340                         struct concrete_pred_expr concrete = (*concrete_exprs)[i];
 341                         bool equality = false;
 342                         switch (concrete.token) {
 343                         case EQUALITY:
 344                                 equality = (value == concrete.value);
 345                                 break;
 346                         case NULLITY:
 347                                 equality = ((void*)value == NULL);
 348                                 break;
 349                         default:
 350                                 model_print("unknown predicate token");
 351                                 break;
 352                         }
 353
 354                         if (equality != concrete.equality) {
 355                                 satisfy_predicate = false;
 356                                 break;
 357                         }
 358                 }
 359
 360                 if (satisfy_predicate) {
 361                         /* Wake up threads */
 362                         thread_id_t tid = concrete_pred->get_tid();
 363                         Thread * thread = model->get_thread(tid);
 364
 365                         //model_print("** thread %d is woken up\n", thread->get_id());
 366                         ((NewFuzzer *)model->get_execution()->getFuzzer())->notify_paused_thread(thread);
 367                 }
 368
 369                 index++;
 370         }
 371 }
 372
 373 WaitObj * ModelHistory::getWaitObj(thread_id_t tid)
 374 {
 375         int thread_id = id_to_int(tid);
 376         int old_size = thrd_wait_obj->size();
 377         if (old_size <= thread_id) {
 378                 thrd_wait_obj->resize(thread_id + 1);
 379                 for (int i = old_size;i < thread_id + 1;i++) {
 380                         (*thrd_wait_obj)[i] = new WaitObj( int_to_id(i) );
 381                 }
 382         }
 383
 384         return (*thrd_wait_obj)[thread_id];
 385 }
 386
 387 void ModelHistory::add_waiting_thread(thread_id_t self_id,
 388                                                                                                                                                         thread_id_t waiting_for_id, FuncNode * target_node, int dist)
 389 {
 390         WaitObj * self_wait_obj = getWaitObj(self_id);
 391         self_wait_obj->add_waiting_for(waiting_for_id, target_node, dist);
 392
 393         /* Update waited-by relation */
 394         WaitObj * other_wait_obj = getWaitObj(waiting_for_id);
 395         other_wait_obj->add_waited_by(self_id);
 396 }
 397
 398 /* Thread tid is woken up (or notified), so it is not waiting for others anymore */
 399 void ModelHistory::remove_waiting_thread(thread_id_t tid)
 400 {
 401         WaitObj * self_wait_obj = getWaitObj(tid);
 402         thrd_id_set_t * waiting_for = self_wait_obj->getWaitingFor();
 403
 404         /* Remove tid from waited_by's */
 405         thrd_id_set_iter * iter = waiting_for->iterator();
 406         while (iter->hasNext()) {
 407                 thread_id_t other_id = iter->next();
 408                 WaitObj * other_wait_obj = getWaitObj(other_id);
 409                 other_wait_obj->remove_waited_by(tid);
 410         }
 411
 412         self_wait_obj->clear_waiting_for();
 413         delete iter;
 414 }
 415
 416 void ModelHistory::stop_waiting_for_node(thread_id_t self_id,
 417                                                                                                                                                                  thread_id_t waiting_for_id, FuncNode * target_node)
 418 {
 419         WaitObj * self_wait_obj = getWaitObj(self_id);
 420         bool thread_removed = self_wait_obj->remove_waiting_for_node(waiting_for_id, target_node);
 421
 422         // model_print("\t%d gives up %d on node %d\n", self_id, waiting_for_id, target_node->get_func_id());
 423
 424         /* If thread self_id is not waiting for waiting_for_id anymore */
 425         if (thread_removed) {
 426                 WaitObj * other_wait_obj = getWaitObj(waiting_for_id);
 427                 other_wait_obj->remove_waited_by(self_id);
 428
 429                 thrd_id_set_t * self_waiting_for = self_wait_obj->getWaitingFor();
 430                 if ( self_waiting_for->isEmpty() ) {
 431                         // model_print("\tthread %d waits for nobody, wake up\n", self_id);
 432                         ModelExecution * execution = model->get_execution();
 433                         Thread * thread = execution->get_thread(self_id);
 434                         ((NewFuzzer *)execution->getFuzzer())->notify_paused_thread(thread);
 435                 }
 436         }
 437 }
 438
 439 SnapVector<inst_act_map_t *> * ModelHistory::getThrdInstActMap(uint32_t func_id)
 440 {
 441         ASSERT(func_id != 0);
 442
 443         SnapVector<inst_act_map_t *> * maps = func_inst_act_maps->get(func_id);
 444         if (maps == NULL) {
 445                 maps = new SnapVector<inst_act_map_t *>();
 446                 func_inst_act_maps->put(func_id, maps);
 447         }
 448
 449         return maps;
 450 }
 451
 452 bool ModelHistory::skip_action(ModelAction * act, SnapList<ModelAction *> * curr_act_list)
 453 {
 454         ASSERT(curr_act_list != NULL);
 455
 456         bool second_part_of_rmw = act->is_rmwc() || act->is_rmw();
 457         modelclock_t curr_seq_number = act->get_seq_number();
 458
 459         /* Skip actions that are second part of a read modify write */
 460         if (second_part_of_rmw)
 461                 return true;
 462
 463         /* Skip actions with the same sequence number */
 464         if (curr_act_list->size() != 0) {
 465                 ModelAction * last_act = curr_act_list->back();
 466                 if (last_act->get_seq_number() == curr_seq_number)
 467                         return true;
 468         }
 469
 470         /* Skip actions that are paused by fuzzer (sequence number is 0) */
 471         if (curr_seq_number == 0)
 472                 return true;
 473
 474         return false;
 475 }
 476
 477 /* Monitor thread tid and decide whether other threads (that are waiting for tid)
 478  * should keep waiting for this thread or not. Shall only be called when a thread
 479  * enters a function.
 480  *
 481  * Heuristics: If the distance from the current FuncNode to some target node
 482  * ever increases, stop waiting for this thread on this target node.
 483  */
 484 void ModelHistory::monitor_waiting_thread(uint32_t func_id, thread_id_t tid)
 485 {
 486         WaitObj * wait_obj = getWaitObj(tid);
 487         thrd_id_set_t * waited_by = wait_obj->getWaitedBy();
 488         FuncNode * curr_node = func_nodes[func_id];
 489
 490         /* For each thread waiting for tid */
 491         thrd_id_set_iter * tid_iter = waited_by->iterator();
 492         while (tid_iter->hasNext()) {
 493                 thread_id_t waited_by_id = tid_iter->next();
 494                 WaitObj * other_wait_obj = getWaitObj(waited_by_id);
 495
 496                 node_set_t * target_nodes = other_wait_obj->getTargetNodes(tid);
 497                 node_set_iter * node_iter = target_nodes->iterator();
 498                 while (node_iter->hasNext()) {
 499                         FuncNode * target = node_iter->next();
 500                         int old_dist = other_wait_obj->lookup_dist(tid, target);
 501                         int new_dist = curr_node->compute_distance(target, old_dist);
 502
 503                         if (new_dist == -1) {
 504                                 stop_waiting_for_node(waited_by_id, tid, target);
 505                         }
 506                 }
 507
 508                 delete node_iter;
 509         }
 510
 511         delete tid_iter;
 512 }
 513
 514 void ModelHistory::monitor_waiting_thread_counter(thread_id_t tid)
 515 {
 516         WaitObj * wait_obj = getWaitObj(tid);
 517         thrd_id_set_t * waited_by = wait_obj->getWaitedBy();
 518
 519         // Thread tid has taken an action, update the counter for threads waiting for tid
 520         thrd_id_set_iter * tid_iter = waited_by->iterator();
 521         while (tid_iter->hasNext()) {
 522                 thread_id_t waited_by_id = tid_iter->next();
 523                 WaitObj * other_wait_obj = getWaitObj(waited_by_id);
 524
 525                 bool expire = other_wait_obj->incr_counter(tid);
 526                 if (expire) {
 527 //                      model_print("thread %d stops waiting for thread %d\n", waited_by_id, tid);
 528                         wait_obj->remove_waited_by(waited_by_id);
 529                         other_wait_obj->remove_waiting_for(tid);
 530
 531                         thrd_id_set_t * other_waiting_for = other_wait_obj->getWaitingFor();
 532                         if ( other_waiting_for->isEmpty() ) {
 533                                 // model_print("\tthread %d waits for nobody, wake up\n", self_id);
 534                                 ModelExecution * execution = model->get_execution();
 535                                 Thread * thread = execution->get_thread(waited_by_id);
 536                                 ((NewFuzzer *)execution->getFuzzer())->notify_paused_thread(thread);
 537                         }
 538                 }
 539         }
 540
 541         delete tid_iter;
 542 }
 543
 544 /* Reallocate some snapshotted memories when new executions start */
 545 void ModelHistory::set_new_exec_flag()
 546 {
 547         for (uint i = 1;i < func_nodes.size();i++) {
 548                 FuncNode * func_node = func_nodes[i];
 549                 func_node->set_new_exec_flag();
 550         }
 551 }
 552
 553 void ModelHistory::dump_func_node_graph()
 554 {
 555         model_print("digraph func_node_graph {\n");
 556         for (uint i = 1;i < func_nodes.size();i++) {
 557                 FuncNode * node = func_nodes[i];
 558                 ModelList<FuncNode *> * out_edges = node->get_out_edges();
 559
 560                 model_print("\"%p\" [label=\"%s\"]\n", node, node->get_func_name());
 561                 mllnode<FuncNode *> * it;
 562                 for (it = out_edges->begin();it != NULL;it = it->getNext()) {
 563                         FuncNode * other = it->getVal();
 564                         model_print("\"%p\" -> \"%p\"\n", node, other);
 565                 }
 566         }
 567         model_print("}\n");
 568 }
 569
 570 void ModelHistory::print_func_node()
 571 {
 572         /* function id starts with 1 */
 573         for (uint32_t i = 1;i < func_nodes.size();i++) {
 574                 FuncNode * func_node = func_nodes[i];
 575                 func_node->print_predicate_tree();
 576
 577 /*
 578                 func_inst_list_mt * entry_insts = func_node->get_entry_insts();
 579                 model_print("function %s has entry actions\n", func_node->get_func_name());
 580
 581                 mllnode<FuncInst*>* it;
 582                 for (it = entry_insts->begin();it != NULL;it=it->getNext()) {
 583                         FuncInst *inst = it->getVal();
 584                         model_print("type: %d, at: %s\n", inst->get_type(), inst->get_position());
 585                 }
 586  */
 587         }
 588 }
 589
 590 void ModelHistory::print_waiting_threads()
 591 {
 592         ModelExecution * execution = model->get_execution();
 593         for (unsigned int i = 0;i < execution->get_num_threads();i++) {
 594                 thread_id_t tid = int_to_id(i);
 595                 WaitObj * wait_obj = getWaitObj(tid);
 596                 wait_obj->print_waiting_for();
 597         }
 598
 599         for (unsigned int i = 0;i < execution->get_num_threads();i++) {
 600                 thread_id_t tid = int_to_id(i);
 601                 WaitObj * wait_obj = getWaitObj(tid);
 602                 wait_obj->print_waited_by();
 603         }
 604 }