funcnode.cc

   1 #include "action.h"
   2 #include "history.h"
   3 #include "funcnode.h"
   4 #include "funcinst.h"
   5 #include "predicate.h"
   6 #include "concretepredicate.h"
   7
   8 #include "model.h"
   9 #include <cmath>
  10
  11 FuncNode::FuncNode(ModelHistory * history) :
  12         history(history),
  13         exit_count(0),
  14         marker(1),
  15         func_inst_map(),
  16         inst_list(),
  17         entry_insts(),
  18         inst_pred_map(128),
  19         inst_id_map(128),
  20         loc_act_map(128),
  21         predicate_tree_position(),
  22         predicate_leaves(),
  23         edge_table(32),
  24         out_edges()
  25 {
  26         predicate_tree_entry = new Predicate(NULL, true);
  27         predicate_tree_entry->add_predicate_expr(NOPREDICATE, NULL, true);
  28
  29         predicate_tree_exit = new Predicate(NULL, false, true);
  30         predicate_tree_exit->set_depth(MAX_DEPTH);
  31
  32         /* Snapshot data structures below */
  33         action_list_buffer = new SnapList<action_list_t *>();
  34         read_locations = new loc_set_t();
  35         write_locations = new loc_set_t();
  36         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0, snapshot_malloc, snapshot_calloc, snapshot_free, int64_hash>();
  37         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  38
  39         //values_may_read_from = new value_set_t();
  40 }
  41
  42 /* Reallocate snapshotted memories when new executions start */
  43 void FuncNode::set_new_exec_flag()
  44 {
  45         action_list_buffer = new SnapList<action_list_t *>();
  46         read_locations = new loc_set_t();
  47         write_locations = new loc_set_t();
  48         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0, snapshot_malloc, snapshot_calloc, snapshot_free, int64_hash>();
  49         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  50
  51         //values_may_read_from = new value_set_t();
  52 }
  53
  54 /* Check whether FuncInst with the same type, position, and location
  55  * as act has been added to func_inst_map or not. If not, add it.
  56  */
  57 void FuncNode::add_inst(ModelAction *act)
  58 {
  59         ASSERT(act);
  60         const char * position = act->get_position();
  61
  62         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  63          * actions are not tagged with their source line numbers
  64          */
  65         if (position == NULL)
  66                 return;
  67
  68         FuncInst * func_inst = func_inst_map.get(position);
  69
  70         /* This position has not been inserted into hashtable before */
  71         if (func_inst == NULL) {
  72                 func_inst = create_new_inst(act);
  73                 func_inst_map.put(position, func_inst);
  74                 return;
  75         }
  76
  77         /* Volatile variables that use ++ or -- syntax may result in read and write actions with the same position */
  78         if (func_inst->get_type() != act->get_type()) {
  79                 FuncInst * collision_inst = func_inst->search_in_collision(act);
  80
  81                 if (collision_inst == NULL) {
  82                         collision_inst = create_new_inst(act);
  83                         func_inst->add_to_collision(collision_inst);
  84                         return;
  85                 } else {
  86                         func_inst = collision_inst;
  87                 }
  88         }
  89
  90         ASSERT(func_inst->get_type() == act->get_type());
  91         int curr_execution_number = model->get_execution_number();
  92
  93         /* Reset locations when new executions start */
  94         if (func_inst->get_execution_number() != curr_execution_number) {
  95                 func_inst->set_location(act->get_location());
  96                 func_inst->set_execution_number(curr_execution_number);
  97         }
  98
  99         /* Mark the memory location of such inst as not unique */
 100         if (func_inst->get_location() != act->get_location())
 101                 func_inst->not_single_location();
 102 }
 103
 104 FuncInst * FuncNode::create_new_inst(ModelAction * act)
 105 {
 106         FuncInst * func_inst = new FuncInst(act, this);
 107         int exec_num = model->get_execution_number();
 108         func_inst->set_execution_number(exec_num);
 109
 110         inst_list.push_back(func_inst);
 111
 112         return func_inst;
 113 }
 114
 115
 116 /* Get the FuncInst with the same type, position, and location
 117  * as act
 118  *
 119  * @return FuncInst with the same type, position, and location as act */
 120 FuncInst * FuncNode::get_inst(ModelAction *act)
 121 {
 122         ASSERT(act);
 123         const char * position = act->get_position();
 124
 125         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
 126          * actions are not tagged with their source line numbers
 127          */
 128         if (position == NULL)
 129                 return NULL;
 130
 131         FuncInst * inst = func_inst_map.get(position);
 132         if (inst == NULL)
 133                 return NULL;
 134
 135         action_type inst_type = inst->get_type();
 136         action_type act_type = act->get_type();
 137
 138         if (inst_type == act_type) {
 139                 return inst;
 140         }
 141         /* RMWRCAS actions are converted to RMW or READ actions */
 142         else if (inst_type == ATOMIC_RMWRCAS &&
 143                                          (act_type == ATOMIC_RMW || act_type == ATOMIC_READ)) {
 144                 return inst;
 145         }
 146         /* Return the FuncInst in the collision list */
 147         else {
 148                 return inst->search_in_collision(act);
 149         }
 150 }
 151
 152
 153 void FuncNode::add_entry_inst(FuncInst * inst)
 154 {
 155         if (inst == NULL)
 156                 return;
 157
 158         mllnode<FuncInst *> * it;
 159         for (it = entry_insts.begin();it != NULL;it = it->getNext()) {
 160                 if (inst == it->getVal())
 161                         return;
 162         }
 163
 164         entry_insts.push_back(inst);
 165 }
 166
 167 /**
 168  * @brief Convert ModelAdtion list to FuncInst list
 169  * @param act_list A list of ModelActions
 170  */
 171 void FuncNode::update_tree(action_list_t * act_list)
 172 {
 173         if (act_list == NULL || act_list->size() == 0)
 174                 return;
 175
 176         HashTable<void *, value_set_t *, uintptr_t, 0> * write_history = history->getWriteHistory();
 177
 178         /* build inst_list from act_list for later processing */
 179         func_inst_list_t inst_list;
 180         action_list_t rw_act_list;
 181
 182         for (sllnode<ModelAction *> * it = act_list->begin();it != NULL;it = it->getNext()) {
 183                 ModelAction * act = it->getVal();
 184                 FuncInst * func_inst = get_inst(act);
 185                 void * loc = act->get_location();
 186
 187                 if (func_inst == NULL)
 188                         continue;
 189
 190                 inst_list.push_back(func_inst);
 191                 bool act_added = false;
 192
 193                 if (act->is_write()) {
 194                         rw_act_list.push_back(act);
 195                         act_added = true;
 196                         if (!write_locations->contains(loc)) {
 197                                 write_locations->add(loc);
 198                                 history->update_loc_wr_func_nodes_map(loc, this);
 199                         }
 200                 }
 201
 202                 if (act->is_read()) {
 203                         if (!act_added)
 204                                 rw_act_list.push_back(act);
 205
 206                         /* If func_inst may only read_from a single location, then:
 207                          *
 208                          * The first time an action reads from some location,
 209                          * import all the values that have been written to this
 210                          * location from ModelHistory and notify ModelHistory
 211                          * that this FuncNode may read from this location.
 212                          */
 213                         if (!read_locations->contains(loc) && func_inst->is_single_location()) {
 214                                 read_locations->add(loc);
 215                                 value_set_t * write_values = write_history->get(loc);
 216                                 add_to_val_loc_map(write_values, loc);
 217                                 history->update_loc_rd_func_nodes_map(loc, this);
 218                         }
 219                 }
 220         }
 221
 222 //      model_print("function %s\n", func_name);
 223 //      print_val_loc_map();
 224
 225         update_inst_tree(&inst_list);
 226         update_predicate_tree(&rw_act_list);
 227
 228 //      print_predicate_tree();
 229 }
 230
 231 /**
 232  * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
 233  * @param inst_list A list of FuncInsts
 234  */
 235 void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
 236 {
 237         if (inst_list == NULL)
 238                 return;
 239         else if (inst_list->size() == 0)
 240                 return;
 241
 242         /* start linking */
 243         sllnode<FuncInst *>* it = inst_list->begin();
 244         sllnode<FuncInst *>* prev;
 245
 246         /* add the first instruction to the list of entry insts */
 247         FuncInst * entry_inst = it->getVal();
 248         add_entry_inst(entry_inst);
 249
 250         it = it->getNext();
 251         while (it != NULL) {
 252                 prev = it->getPrev();
 253
 254                 FuncInst * prev_inst = prev->getVal();
 255                 FuncInst * curr_inst = it->getVal();
 256
 257                 prev_inst->add_succ(curr_inst);
 258                 curr_inst->add_pred(prev_inst);
 259
 260                 it = it->getNext();
 261         }
 262 }
 263
 264 void FuncNode::update_predicate_tree(action_list_t * act_list)
 265 {
 266         if (act_list == NULL || act_list->size() == 0)
 267                 return;
 268
 269         incr_marker();
 270         uint32_t inst_counter = 0;
 271
 272         // Clear hashtables
 273         loc_act_map.reset();    /* Only need to store the locations of read actions */
 274         inst_pred_map.reset();
 275         inst_id_map.reset();
 276
 277         sllnode<ModelAction *> *it = act_list->begin();
 278         Predicate * curr_pred = predicate_tree_entry;
 279         while (it != NULL) {
 280                 ModelAction * next_act = it->getVal();
 281                 FuncInst * next_inst = get_inst(next_act);
 282                 next_inst->set_associated_act(next_act, marker);
 283
 284                 SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
 285                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &unset_predicates);
 286
 287                 // A branch with unset predicate expression is detected
 288                 if (!branch_found && unset_predicates.size() != 0) {
 289                         ASSERT(unset_predicates.size() == 1);
 290                         Predicate * one_branch = unset_predicates[0];
 291
 292                         bool amended = amend_predicate_expr(curr_pred, next_inst, next_act);
 293                         if (amended)
 294                                 continue;
 295                         else {
 296                                 curr_pred = one_branch;
 297                                 branch_found = true;
 298                         }
 299                 }
 300
 301                 // Detect loops
 302                 if (!branch_found && inst_id_map.contains(next_inst)) {
 303                         FuncInst * curr_inst = curr_pred->get_func_inst();
 304                         uint32_t curr_id = inst_id_map.get(curr_inst);
 305                         uint32_t next_id = inst_id_map.get(next_inst);
 306
 307                         if (curr_id >= next_id) {
 308                                 Predicate * old_pred = inst_pred_map.get(next_inst);
 309                                 Predicate * back_pred = old_pred->get_parent();
 310
 311                                 curr_pred->add_backedge(back_pred);
 312                                 curr_pred = back_pred;
 313                                 continue;
 314                         }
 315                 }
 316
 317                 // Generate new branches
 318                 if (!branch_found) {
 319                         SnapVector<struct half_pred_expr *> half_pred_expressions;
 320                         infer_predicates(next_inst, next_act, &half_pred_expressions);
 321                         generate_predicates(curr_pred, next_inst, &half_pred_expressions);
 322                         continue;
 323                 }
 324
 325                 if (next_act->is_write())
 326                         curr_pred->set_write(true);
 327
 328                 if (next_act->is_read()) {
 329                         loc_act_map.put(next_act->get_location(), next_act);
 330                 }
 331
 332                 inst_pred_map.put(next_inst, curr_pred);
 333                 if (!inst_id_map.contains(next_inst))
 334                         inst_id_map.put(next_inst, inst_counter++);
 335
 336                 it = it->getNext();
 337                 curr_pred->incr_expl_count();
 338         }
 339
 340         if (curr_pred->get_exit() == NULL) {
 341                 // Exit predicate is unset yet
 342                 curr_pred->set_exit(predicate_tree_exit);
 343         }
 344
 345         update_predicate_tree_weight();
 346 }
 347
 348 /* Given curr_pred and next_inst, find the branch following curr_pred that
 349  * contains next_inst and the correct predicate.
 350  * @return true if branch found, false otherwise.
 351  */
 352 bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst,
 353 ModelAction * next_act, SnapVector<Predicate *> * unset_predicates)
 354 {
 355         /* Check if a branch with func_inst and corresponding predicate exists */
 356         bool branch_found = false;
 357         ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
 358         for (uint i = 0;i < branches->size();i++) {
 359                 Predicate * branch = (*branches)[i];
 360                 if (branch->get_func_inst() != next_inst)
 361                         continue;
 362
 363                 /* Check against predicate expressions */
 364                 bool predicate_correct = true;
 365                 PredExprSet * pred_expressions = branch->get_pred_expressions();
 366                 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
 367
 368                 /* Only read and rmw actions my have unset predicate expressions */
 369                 if (pred_expressions->getSize() == 0) {
 370                         predicate_correct = false;
 371                         unset_predicates->push_back(branch);
 372                 }
 373
 374                 while (pred_expr_it->hasNext()) {
 375                         pred_expr * pred_expression = pred_expr_it->next();
 376                         uint64_t last_read, next_read;
 377                         bool equality;
 378
 379                         switch(pred_expression->token) {
 380                                 case NOPREDICATE:
 381                                         predicate_correct = true;
 382                                         break;
 383                                 case EQUALITY:
 384                                         FuncInst * to_be_compared;
 385                                         ModelAction * last_act;
 386
 387                                         to_be_compared = pred_expression->func_inst;
 388                                         last_act = to_be_compared->get_associated_act(marker);
 389
 390                                         last_read = last_act->get_reads_from_value();
 391                                         next_read = next_act->get_reads_from_value();
 392                                         equality = (last_read == next_read);
 393                                         if (equality != pred_expression->value)
 394                                                 predicate_correct = false;
 395
 396                                         break;
 397                                 case NULLITY:
 398                                         next_read = next_act->get_reads_from_value();
 399                                         // TODO: implement likely to be null
 400                                         equality = ( (void*) (next_read & 0xffffffff) == NULL);
 401                                         if (equality != pred_expression->value)
 402                                                 predicate_correct = false;
 403                                         break;
 404                                 default:
 405                                         predicate_correct = false;
 406                                         model_print("unkown predicate token\n");
 407                                         break;
 408                         }
 409                 }
 410
 411                 if (predicate_correct) {
 412                         *curr_pred = branch;
 413                         branch_found = true;
 414                         break;
 415                 }
 416         }
 417
 418         return branch_found;
 419 }
 420
 421 /* Infer predicate expressions, which are generated in FuncNode::generate_predicates */
 422 void FuncNode::infer_predicates(FuncInst * next_inst, ModelAction * next_act,
 423 SnapVector<struct half_pred_expr *> * half_pred_expressions)
 424 {
 425         void * loc = next_act->get_location();
 426
 427         if (next_inst->is_read()) {
 428                 /* read + rmw */
 429                 if ( loc_act_map.contains(loc) ) {
 430                         ModelAction * last_act = loc_act_map.get(loc);
 431                         FuncInst * last_inst = get_inst(last_act);
 432                         struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 433                         half_pred_expressions->push_back(expression);
 434                 } else if ( next_inst->is_single_location() ) {
 435                         loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
 436
 437                         if (loc_may_equal != NULL) {
 438                                 loc_set_iter * loc_it = loc_may_equal->iterator();
 439                                 while (loc_it->hasNext()) {
 440                                         void * neighbor = loc_it->next();
 441                                         if (loc_act_map.contains(neighbor)) {
 442                                                 ModelAction * last_act = loc_act_map.get(neighbor);
 443                                                 FuncInst * last_inst = get_inst(last_act);
 444
 445                                                 struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 446                                                 half_pred_expressions->push_back(expression);
 447                                         }
 448                                 }
 449                         }
 450                 } else {
 451                         // next_inst is not single location
 452                         uint64_t read_val = next_act->get_reads_from_value();
 453
 454                         // only infer NULLITY predicate when it is actually NULL.
 455                         if ( (void*)read_val == NULL) {
 456                                 struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
 457                                 half_pred_expressions->push_back(expression);
 458                         }
 459                 }
 460         } else {
 461                 /* Pure writes */
 462                 // TODO: do anything here?
 463         }
 464 }
 465
 466 /* Able to generate complex predicates when there are multiple predciate expressions */
 467 void FuncNode::generate_predicates(Predicate * curr_pred, FuncInst * next_inst,
 468 SnapVector<struct half_pred_expr *> * half_pred_expressions)
 469 {
 470         if (half_pred_expressions->size() == 0) {
 471                 Predicate * new_pred = new Predicate(next_inst);
 472                 curr_pred->add_child(new_pred);
 473                 new_pred->set_parent(curr_pred);
 474
 475                 /* Maintain predicate leaves */
 476                 predicate_leaves.add(new_pred);
 477                 predicate_leaves.remove(curr_pred);
 478
 479                 /* entry predicates and predicates containing pure write actions
 480                  * have no predicate expressions */
 481                 if ( curr_pred->is_entry_predicate() )
 482                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 483                 else if (next_inst->is_write()) {
 484                         /* next_inst->is_write() <==> pure writes */
 485                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 486                 }
 487
 488                 return;
 489         }
 490
 491         SnapVector<Predicate *> predicates;
 492
 493         struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
 494         predicates.push_back(new Predicate(next_inst));
 495         predicates.push_back(new Predicate(next_inst));
 496
 497         predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 498         predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 499
 500         for (uint i = 1;i < half_pred_expressions->size();i++) {
 501                 half_expr = (*half_pred_expressions)[i];
 502
 503                 uint old_size = predicates.size();
 504                 for (uint j = 0;j < old_size;j++) {
 505                         Predicate * pred = predicates[j];
 506                         Predicate * new_pred = new Predicate(next_inst);
 507                         new_pred->copy_predicate_expr(pred);
 508
 509                         pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 510                         new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 511
 512                         predicates.push_back(new_pred);
 513                 }
 514         }
 515
 516         for (uint i = 0;i < predicates.size();i++) {
 517                 Predicate * pred= predicates[i];
 518                 curr_pred->add_child(pred);
 519                 pred->set_parent(curr_pred);
 520
 521                 /* Add new predicate leaves */
 522                 predicate_leaves.add(pred);
 523         }
 524
 525         /* Remove predicate node that has children */
 526         predicate_leaves.remove(curr_pred);
 527
 528         /* Free memories allocated by infer_predicate */
 529         for (uint i = 0;i < half_pred_expressions->size();i++) {
 530                 struct half_pred_expr * tmp = (*half_pred_expressions)[i];
 531                 snapshot_free(tmp);
 532         }
 533 }
 534
 535 /* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
 536 bool FuncNode::amend_predicate_expr(Predicate * curr_pred, FuncInst * next_inst, ModelAction * next_act)
 537 {
 538         // there should only be only child
 539         Predicate * unset_pred = curr_pred->get_children()->back();
 540         uint64_t read_val = next_act->get_reads_from_value();
 541
 542         // only generate NULLITY predicate when it is actually NULL.
 543         if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
 544                 Predicate * new_pred = new Predicate(next_inst);
 545
 546                 curr_pred->add_child(new_pred);
 547                 new_pred->set_parent(curr_pred);
 548
 549                 unset_pred->add_predicate_expr(NULLITY, NULL, false);
 550                 new_pred->add_predicate_expr(NULLITY, NULL, true);
 551
 552                 return true;
 553         }
 554
 555         return false;
 556 }
 557
 558 void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 559 {
 560         loc_set_t * locations = val_loc_map->get(val);
 561
 562         if (locations == NULL) {
 563                 locations = new loc_set_t();
 564                 val_loc_map->put(val, locations);
 565         }
 566
 567         update_loc_may_equal_map(loc, locations);
 568         locations->add(loc);
 569         // values_may_read_from->add(val);
 570 }
 571
 572 void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
 573 {
 574         if (values == NULL)
 575                 return;
 576
 577         value_set_iter * it = values->iterator();
 578         while (it->hasNext()) {
 579                 uint64_t val = it->next();
 580                 add_to_val_loc_map(val, loc);
 581         }
 582 }
 583
 584 void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 585 {
 586         if ( old_locations->contains(new_loc) )
 587                 return;
 588
 589         loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
 590
 591         if (neighbors == NULL) {
 592                 neighbors = new loc_set_t();
 593                 loc_may_equal_map->put(new_loc, neighbors);
 594         }
 595
 596         loc_set_iter * loc_it = old_locations->iterator();
 597         while (loc_it->hasNext()) {
 598                 // new_loc: { old_locations, ... }
 599                 void * member = loc_it->next();
 600                 neighbors->add(member);
 601
 602                 // for each i in old_locations, i : { new_loc, ... }
 603                 loc_set_t * _neighbors = loc_may_equal_map->get(member);
 604                 if (_neighbors == NULL) {
 605                         _neighbors = new loc_set_t();
 606                         loc_may_equal_map->put(member, _neighbors);
 607                 }
 608                 _neighbors->add(new_loc);
 609         }
 610 }
 611
 612 /* Every time a thread enters a function, set its position to the predicate tree entry */
 613 void FuncNode::init_predicate_tree_position(thread_id_t tid)
 614 {
 615         int thread_id = id_to_int(tid);
 616         if (predicate_tree_position.size() <= (uint) thread_id)
 617                 predicate_tree_position.resize(thread_id + 1);
 618
 619         predicate_tree_position[thread_id] = predicate_tree_entry;
 620 }
 621
 622 void FuncNode::set_predicate_tree_position(thread_id_t tid, Predicate * pred)
 623 {
 624         int thread_id = id_to_int(tid);
 625         predicate_tree_position[thread_id] = pred;
 626 }
 627
 628 /* @return The position of a thread in a predicate tree */
 629 Predicate * FuncNode::get_predicate_tree_position(thread_id_t tid)
 630 {
 631         int thread_id = id_to_int(tid);
 632         return predicate_tree_position[thread_id];
 633 }
 634
 635 /* Make sure elements of thrd_inst_act_map are initialized properly when threads enter functions */
 636 void FuncNode::init_inst_act_map(thread_id_t tid)
 637 {
 638         int thread_id = id_to_int(tid);
 639         SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
 640         uint old_size = thrd_inst_act_map->size();
 641
 642         if (thrd_inst_act_map->size() <= (uint) thread_id) {
 643                 uint new_size = thread_id + 1;
 644                 thrd_inst_act_map->resize(new_size);
 645
 646                 for (uint i = old_size;i < new_size;i++)
 647                         (*thrd_inst_act_map)[i] = new inst_act_map_t(128);
 648         }
 649 }
 650
 651 /* Reset elements of thrd_inst_act_map when threads exit functions */
 652 void FuncNode::reset_inst_act_map(thread_id_t tid)
 653 {
 654         int thread_id = id_to_int(tid);
 655         SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
 656
 657         inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
 658         map->reset();
 659 }
 660
 661 void FuncNode::update_inst_act_map(thread_id_t tid, ModelAction * read_act)
 662 {
 663         int thread_id = id_to_int(tid);
 664         SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
 665
 666         inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
 667         FuncInst * read_inst = get_inst(read_act);
 668         map->put(read_inst, read_act);
 669 }
 670
 671 inst_act_map_t * FuncNode::get_inst_act_map(thread_id_t tid)
 672 {
 673         int thread_id = id_to_int(tid);
 674         SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
 675
 676         return (*thrd_inst_act_map)[thread_id];
 677 }
 678
 679 /* Add FuncNodes that this node may follow */
 680 void FuncNode::add_out_edge(FuncNode * other)
 681 {
 682         if ( !edge_table.contains(other) ) {
 683                 edge_table.put(other, OUT_EDGE);
 684                 out_edges.push_back(other);
 685                 return;
 686         }
 687
 688         edge_type_t edge = edge_table.get(other);
 689         if (edge == IN_EDGE) {
 690                 edge_table.put(other, BI_EDGE);
 691                 out_edges.push_back(other);
 692         }
 693 }
 694
 695 /* Compute the distance between this FuncNode and the target node.
 696  * Return -1 if the target node is unreachable or the actual distance
 697  * is greater than max_step.
 698  */
 699 int FuncNode::compute_distance(FuncNode * target, int max_step)
 700 {
 701         if (target == NULL)
 702                 return -1;
 703         else if (target == this)
 704                 return 0;
 705
 706         SnapList<FuncNode *> queue;
 707         HashTable<FuncNode *, int, uintptr_t, 0> distances(128);
 708
 709         queue.push_back(this);
 710         distances.put(this, 0);
 711
 712         while (!queue.empty()) {
 713                 FuncNode * curr = queue.front();
 714                 queue.pop_front();
 715                 int dist = distances.get(curr);
 716
 717                 if (max_step <= dist)
 718                         return -1;
 719
 720                 ModelList<FuncNode *> * outEdges = curr->get_out_edges();
 721                 mllnode<FuncNode *> * it;
 722                 for (it = outEdges->begin();it != NULL;it = it->getNext()) {
 723                         FuncNode * out_node = it->getVal();
 724
 725                         /* This node has not been visited before */
 726                         if ( !distances.contains(out_node) ) {
 727                                 if (out_node == target)
 728                                         return dist + 1;
 729
 730                                 queue.push_back(out_node);
 731                                 distances.put(out_node, dist + 1);
 732                         }
 733                 }
 734         }
 735
 736         /* Target node is unreachable */
 737         return -1;
 738 }
 739
 740 /* Implement quick sort to sort leaves before assigning base scores */
 741 static int partition(SnapVector<Predicate *> * arr, int low, int high)
 742 {
 743         unsigned int pivot = (*arr)[high]->get_depth();
 744         int i = low - 1;
 745
 746         for (int j = low; j <= high - 1; j++) {
 747                 if ( (*arr)[j]->get_depth() < pivot ) {
 748                         i++;
 749                         Predicate *tmp = (*arr)[i];
 750                         (*arr)[i] = (*arr)[j];
 751                         (*arr)[j] = tmp;
 752                 }
 753         }
 754
 755         Predicate * tmp = (*arr)[i + 1];
 756         (*arr)[i + 1] = (*arr)[high];
 757         (*arr)[high] = tmp;
 758
 759         return i + 1;
 760 }
 761
 762 /* Implement quick sort to sort leaves before assigning base scores */
 763 static void quickSort(SnapVector<Predicate *> * arr, int low, int high)
 764 {
 765         if (low < high) {
 766                 int pi = partition(arr, low, high);
 767
 768                 quickSort(arr, low, pi - 1);
 769                 quickSort(arr, pi + 1, high);
 770         }
 771 }
 772
 773 void FuncNode::assign_initial_weight()
 774 {
 775         PredSetIter * it = predicate_leaves.iterator();
 776         SnapVector<Predicate *> leaves;
 777         while (it->hasNext()) {
 778                 Predicate * pred = it->next();
 779                 double weight = 100.0 / sqrt(pred->get_expl_count() + 1);
 780                 pred->set_weight(weight);
 781                 leaves.push_back(pred);
 782         }
 783
 784         quickSort(&leaves, 0, leaves.size() - 1);
 785
 786         // assign scores for internal nodes;
 787         while ( !leaves.empty() ) {
 788                 Predicate * leaf = leaves.back();
 789                 leaves.pop_back();
 790
 791                 Predicate * curr = leaf->get_parent();
 792                 while (curr != NULL) {
 793                         if (curr->get_weight() != 0) {
 794                                 // Has been exlpored
 795                                 break;
 796                         }
 797
 798                         ModelVector<Predicate *> * children = curr->get_children();
 799                         double weight_sum = 0;
 800                         bool has_unassigned_node = false;
 801
 802                         for (uint i = 0; i < children->size(); i++) {
 803                                 Predicate * child = (*children)[i];
 804
 805                                 // If a child has unassigned weight
 806                                 double weight = child->get_weight();
 807                                 if (weight == 0) {
 808                                         has_unassigned_node = true;
 809                                         break;
 810                                 } else
 811                                         weight_sum += weight;
 812                         }
 813
 814                         if (!has_unassigned_node) {
 815                                 double average_weight = (double) weight_sum / (double) children->size();
 816                                 double weight = average_weight * pow(0.9, curr->get_depth());
 817                                 curr->set_weight(weight);
 818                         } else
 819                                 break;
 820
 821                         curr = curr->get_parent();
 822                 }
 823         }
 824 }
 825
 826 void FuncNode::update_predicate_tree_weight()
 827 {
 828         if (marker == 2) {
 829                 // Predicate tree is initially built
 830                 assign_initial_weight();
 831         } else {
 832
 833         }
 834 }
 835
 836 void FuncNode::print_predicate_tree()
 837 {
 838         model_print("digraph function_%s {\n", func_name);
 839         predicate_tree_entry->print_pred_subtree();
 840         predicate_tree_exit->print_predicate();
 841         model_print("}\n");     // end of graph
 842 }