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