funcnode.cc

   1 #include "funcnode.h"
   2
   3 FuncNode::FuncNode(ModelHistory * history) :
   4         history(history),
   5         predicate_tree_initialized(false),
   6         exit_count(0),
   7         func_inst_map(),
   8         inst_list(),
   9         entry_insts(),
  10 //      thrd_read_map(),
  11         action_list_buffer(),
  12         predicate_tree_position()
  13 {
  14         predicate_tree_entry = new Predicate(NULL, true);
  15         predicate_tree_entry->add_predicate_expr(NOPREDICATE, NULL, true);
  16
  17         // memories that are reclaimed after each execution
  18         read_locations = new loc_set_t();
  19         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
  20         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  21         //values_may_read_from = new value_set_t();
  22 }
  23
  24 /* Reallocate snapshotted memories when new executions start */
  25 void FuncNode::set_new_exec_flag()
  26 {
  27 //      for (uint i = 0; i < thrd_read_map.size(); i++)
  28 //              thrd_read_map[i] = new read_map_t();
  29
  30         for (mllnode<FuncInst *> * it = inst_list.begin(); it != NULL; it = it->getNext()) {
  31                 FuncInst * inst = it->getVal();
  32                 inst->unset_location();
  33         }
  34
  35         read_locations = new loc_set_t();
  36         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
  37         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  38         //values_may_read_from = new value_set_t();
  39 }
  40
  41 /* Check whether FuncInst with the same type, position, and location
  42  * as act has been added to func_inst_map or not. If not, add it.
  43  *
  44  * Note: currently, actions with the same position are filtered out by process_action,
  45  * so the collision list of FuncInst is not used. May remove it later.
  46  */
  47 void FuncNode::add_inst(ModelAction *act)
  48 {
  49         ASSERT(act);
  50         const char * position = act->get_position();
  51
  52         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  53          * actions are not tagged with their source line numbers
  54          */
  55         if (position == NULL)
  56                 return;
  57
  58         if ( func_inst_map.contains(position) ) {
  59                 FuncInst * inst = func_inst_map.get(position);
  60
  61                 ASSERT(inst->get_type() == act->get_type());
  62
  63                 // locations are set to NULL when new executions start
  64                 if (inst->get_location() == NULL)
  65                         inst->set_location(act->get_location());
  66
  67                 if (inst->get_location() != act->get_location())
  68                         inst->not_single_location();
  69
  70                 return;
  71         }
  72
  73         FuncInst * func_inst = new FuncInst(act, this);
  74
  75         func_inst_map.put(position, func_inst);
  76         inst_list.push_back(func_inst);
  77 }
  78
  79 /* Get the FuncInst with the same type, position, and location
  80  * as act
  81  *
  82  * @return FuncInst with the same type, position, and location as act */
  83 FuncInst * FuncNode::get_inst(ModelAction *act)
  84 {
  85         ASSERT(act);
  86         const char * position = act->get_position();
  87
  88         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  89          * actions are not tagged with their source line numbers
  90          */
  91         if (position == NULL)
  92                 return NULL;
  93
  94         FuncInst * inst = func_inst_map.get(position);
  95         if (inst == NULL)
  96                 return NULL;
  97
  98         action_type inst_type = inst->get_type();
  99         action_type act_type = act->get_type();
 100
 101         // else if branch: an RMWRCAS action is converted to a RMW or READ action
 102         if (inst_type == act_type)
 103                 return inst;
 104         else if (inst_type == ATOMIC_RMWRCAS &&
 105                         (act_type == ATOMIC_RMW || act_type == ATOMIC_READ))
 106                 return inst;
 107
 108         return NULL;
 109 }
 110
 111
 112 void FuncNode::add_entry_inst(FuncInst * inst)
 113 {
 114         if (inst == NULL)
 115                 return;
 116
 117         mllnode<FuncInst *> * it;
 118         for (it = entry_insts.begin(); it != NULL; it = it->getNext()) {
 119                 if (inst == it->getVal())
 120                         return;
 121         }
 122
 123         entry_insts.push_back(inst);
 124 }
 125
 126 /**
 127  * @brief Convert ModelAdtion list to FuncInst list
 128  * @param act_list A list of ModelActions
 129  */
 130 void FuncNode::update_tree(action_list_t * act_list)
 131 {
 132         if (act_list == NULL || act_list->size() == 0)
 133                 return;
 134
 135         HashTable<void *, value_set_t *, uintptr_t, 4> * write_history = history->getWriteHistory();
 136
 137         /* build inst_list from act_list for later processing */
 138         func_inst_list_t inst_list;
 139         action_list_t read_act_list;
 140
 141         for (sllnode<ModelAction *> * it = act_list->begin(); it != NULL; it = it->getNext()) {
 142                 ModelAction * act = it->getVal();
 143                 FuncInst * func_inst = get_inst(act);
 144
 145                 if (func_inst == NULL)
 146                         continue;
 147
 148                 inst_list.push_back(func_inst);
 149
 150                 if (func_inst->is_read()) {
 151                         read_act_list.push_back(act);
 152
 153                         /* the first time an action reads from some location, import all the values that have
 154                          * been written to this location from ModelHistory and notify ModelHistory that this
 155                          * FuncNode may read from this location.
 156                          */
 157                         void * loc = act->get_location();
 158                         if (!read_locations->contains(loc)) {
 159                                 read_locations->add(loc);
 160                                 value_set_t * write_values = write_history->get(loc);
 161                                 add_to_val_loc_map(write_values, loc);
 162                                 history->add_to_loc_func_nodes_map(loc, this);
 163                         }
 164                 }
 165         }
 166
 167 //      model_print("function %s\n", func_name);
 168 //      print_val_loc_map();
 169
 170         update_inst_tree(&inst_list);
 171         update_predicate_tree(&read_act_list);
 172
 173 //      print_predicate_tree();
 174 }
 175
 176 /**
 177  * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
 178  * @param inst_list A list of FuncInsts
 179  */
 180 void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
 181 {
 182         if (inst_list == NULL)
 183                 return;
 184         else if (inst_list->size() == 0)
 185                 return;
 186
 187         /* start linking */
 188         sllnode<FuncInst *>* it = inst_list->begin();
 189         sllnode<FuncInst *>* prev;
 190
 191         /* add the first instruction to the list of entry insts */
 192         FuncInst * entry_inst = it->getVal();
 193         add_entry_inst(entry_inst);
 194
 195         it = it->getNext();
 196         while (it != NULL) {
 197                 prev = it->getPrev();
 198
 199                 FuncInst * prev_inst = prev->getVal();
 200                 FuncInst * curr_inst = it->getVal();
 201
 202                 prev_inst->add_succ(curr_inst);
 203                 curr_inst->add_pred(prev_inst);
 204
 205                 it = it->getNext();
 206         }
 207 }
 208
 209 /* @param tid thread id
 210  * Store the values read by atomic read actions into thrd_read_map */
 211 void FuncNode::store_read(ModelAction * act, thread_id_t tid)
 212 {
 213 /*
 214         ASSERT(act);
 215
 216         void * location = act->get_location();
 217         uint64_t read_from_val = act->get_reads_from_value();
 218
 219         // resize and initialize
 220         uint32_t old_size = thrd_read_map.size();
 221         if (old_size <= tid) {
 222                 thrd_read_map.resize(tid + 1);
 223                 for (uint32_t i = old_size; i < tid + 1;i++)
 224                         thrd_read_map[i] = new read_map_t();
 225         }
 226
 227         read_map_t * read_map = thrd_read_map[tid];
 228         read_map->put(location, read_from_val);
 229 */
 230 }
 231
 232 uint64_t FuncNode::query_last_read(void * location, thread_id_t tid)
 233 {
 234 /*
 235         if (thrd_read_map.size() <= tid)
 236                 return VALUE_NONE;
 237
 238         read_map_t * read_map = thrd_read_map[tid];
 239
 240         // last read value not found
 241         if ( !read_map->contains(location) )
 242                 return VALUE_NONE;
 243
 244         uint64_t read_val = read_map->get(location);
 245         return read_val;
 246 */
 247 }
 248
 249 /* @param tid thread id
 250  * Reset read map for a thread. This function shall only be called
 251  * when a thread exits a function
 252  */
 253 void FuncNode::clear_read_map(thread_id_t tid)
 254 {
 255 /*
 256         if (thrd_read_map.size() <= tid)
 257                 return;
 258
 259         thrd_read_map[tid]->reset();
 260 */
 261 }
 262
 263 void FuncNode::update_predicate_tree(action_list_t * act_list)
 264 {
 265         if (act_list == NULL || act_list->size() == 0)
 266                 return;
 267
 268         /* map a FuncInst to the its predicate */
 269         HashTable<FuncInst *, Predicate *, uintptr_t, 0> inst_pred_map(128);
 270
 271         // number FuncInsts to detect loops
 272         HashTable<FuncInst *, uint32_t, uintptr_t, 0> inst_id_map(128);
 273         uint32_t inst_counter = 0;
 274
 275         HashTable<void *, ModelAction *, uintptr_t, 0> loc_act_map(128);
 276         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> inst_act_map(128);
 277
 278         sllnode<ModelAction *> *it = act_list->begin();
 279         Predicate * curr_pred = predicate_tree_entry;
 280         while (it != NULL) {
 281                 ModelAction * next_act = it->getVal();
 282                 FuncInst * next_inst = get_inst(next_act);
 283
 284                 SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
 285                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, &unset_predicates);
 286
 287                 // no predicate expressions
 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
 314                                 continue;
 315                         }
 316                 }
 317
 318                 // generate new branches
 319                 if (!branch_found) {
 320                         SnapVector<struct half_pred_expr *> half_pred_expressions;
 321                         void * loc = next_act->get_location();
 322
 323                         if ( loc_act_map.contains(loc) ) {
 324                                 ModelAction * last_act = loc_act_map.get(loc);
 325                                 FuncInst * last_inst = get_inst(last_act);
 326                                 struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 327                                 half_pred_expressions.push_back(expression);
 328                         } else if ( next_inst->is_single_location() ){
 329                                 loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
 330
 331                                 if (loc_may_equal != NULL) {
 332                                         loc_set_iter * loc_it = loc_may_equal->iterator();
 333                                         while (loc_it->hasNext()) {
 334                                                 void * neighbor = loc_it->next();
 335                                                 if (loc_act_map.contains(neighbor)) {
 336                                                         ModelAction * last_act = loc_act_map.get(neighbor);
 337                                                         FuncInst * last_inst = get_inst(last_act);
 338
 339                                                         struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 340                                                         half_pred_expressions.push_back(expression);
 341                                                 }
 342                                         }
 343                                 }
 344                         } else {
 345                                 // next_inst is not single location
 346                                 uint64_t read_val = next_act->get_reads_from_value();
 347
 348                                 // only generate NULLITY predicate when it is actually NULL.
 349                                 if ( (void*)read_val == NULL) {
 350                                         struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
 351                                         half_pred_expressions.push_back(expression);
 352                                 }
 353                         }
 354
 355                         if (half_pred_expressions.size() == 0) {
 356                                 // no predicate needs to be generated
 357                                 Predicate * new_pred = new Predicate(next_inst);
 358                                 curr_pred->add_child(new_pred);
 359                                 new_pred->set_parent(curr_pred);
 360
 361                                 if (curr_pred->is_entry_predicate())
 362                                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 363
 364                                 curr_pred = new_pred;
 365                         } else {
 366                                 generate_predicate(&curr_pred, next_inst, &half_pred_expressions);
 367                                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, NULL);
 368                                 ASSERT(branch_found);
 369                         }
 370                 }
 371
 372                 inst_pred_map.put(next_inst, curr_pred);
 373                 if (!inst_id_map.contains(next_inst))
 374                         inst_id_map.put(next_inst, inst_counter++);
 375
 376                 loc_act_map.put(next_act->get_location(), next_act);
 377                 inst_act_map.put(next_inst, next_act);
 378                 it = it->getNext();
 379         }
 380 }
 381
 382 /* Given curr_pred and next_inst, find the branch following curr_pred that
 383  * contains next_inst and the correct predicate.
 384  * @return true if branch found, false otherwise.
 385  */
 386 bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act,
 387         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> * inst_act_map,
 388         SnapVector<Predicate *> * unset_predicates)
 389 {
 390         /* check if a branch with func_inst and corresponding predicate exists */
 391         bool branch_found = false;
 392         ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
 393         for (uint i = 0; i < branches->size(); i++) {
 394                 Predicate * branch = (*branches)[i];
 395                 if (branch->get_func_inst() != next_inst)
 396                         continue;
 397
 398                 /* check against predicate expressions */
 399                 bool predicate_correct = true;
 400                 PredExprSet * pred_expressions = branch->get_pred_expressions();
 401                 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
 402
 403                 if (pred_expressions->getSize() == 0) {
 404                         predicate_correct = false;
 405                         unset_predicates->push_back(branch);
 406                 }
 407
 408                 while (pred_expr_it->hasNext()) {
 409                         pred_expr * pred_expression = pred_expr_it->next();
 410                         uint64_t last_read, next_read;
 411                         bool equality;
 412
 413                         switch(pred_expression->token) {
 414                                 case NOPREDICATE:
 415                                         predicate_correct = true;
 416                                         break;
 417                                 case EQUALITY:
 418                                         FuncInst * to_be_compared;
 419                                         ModelAction * last_act;
 420
 421                                         to_be_compared = pred_expression->func_inst;
 422                                         last_act = inst_act_map->get(to_be_compared);
 423
 424                                         last_read = last_act->get_reads_from_value();
 425                                         next_read = next_act->get_reads_from_value();
 426                                         equality = (last_read == next_read);
 427                                         if (equality != pred_expression->value)
 428                                                 predicate_correct = false;
 429
 430                                         break;
 431                                 case NULLITY:
 432                                         next_read = next_act->get_reads_from_value();
 433                                         equality = ((void*)next_read == NULL);
 434                                         if (equality != pred_expression->value)
 435                                                 predicate_correct = false;
 436                                         break;
 437                                 default:
 438                                         predicate_correct = false;
 439                                         model_print("unkown predicate token\n");
 440                                         break;
 441                         }
 442                 }
 443
 444                 if (predicate_correct) {
 445                         *curr_pred = branch;
 446                         branch_found = true;
 447                         break;
 448                 }
 449         }
 450
 451         return branch_found;
 452 }
 453
 454 /* Able to generate complex predicates when there are multiple predciate expressions */
 455 void FuncNode::generate_predicate(Predicate ** curr_pred, FuncInst * next_inst,
 456         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 457 {
 458         ASSERT(half_pred_expressions->size() != 0);
 459         SnapVector<Predicate *> predicates;
 460
 461         struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
 462         predicates.push_back(new Predicate(next_inst));
 463         predicates.push_back(new Predicate(next_inst));
 464
 465         predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 466         predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 467
 468         for (uint i = 1; i < half_pred_expressions->size(); i++) {
 469                 half_expr = (*half_pred_expressions)[i];
 470
 471                 uint old_size = predicates.size();
 472                 for (uint j = 0; j < old_size; j++) {
 473                         Predicate * pred = predicates[j];
 474                         Predicate * new_pred = new Predicate(next_inst);
 475                         new_pred->copy_predicate_expr(pred);
 476
 477                         pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 478                         new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 479
 480                         predicates.push_back(new_pred);
 481                 }
 482         }
 483
 484         for (uint i = 0; i < predicates.size(); i++) {
 485                 Predicate * pred= predicates[i];
 486                 (*curr_pred)->add_child(pred);
 487                 pred->set_parent(*curr_pred);
 488         }
 489 }
 490
 491 /* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
 492 bool FuncNode::amend_predicate_expr(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act)
 493 {
 494         // there should only be only child
 495         Predicate * unset_pred = (*curr_pred)->get_children()->back();
 496         uint64_t read_val = next_act->get_reads_from_value();
 497
 498         // only generate NULLITY predicate when it is actually NULL.
 499         if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
 500                 Predicate * new_pred = new Predicate(next_inst);
 501
 502                 (*curr_pred)->add_child(new_pred);
 503                 new_pred->set_parent(*curr_pred);
 504
 505                 unset_pred->add_predicate_expr(NULLITY, NULL, false);
 506                 new_pred->add_predicate_expr(NULLITY, NULL, true);
 507
 508                 return true;
 509         }
 510
 511         return false;
 512 }
 513
 514 void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 515 {
 516         loc_set_t * locations = val_loc_map->get(val);
 517
 518         if (locations == NULL) {
 519                 locations = new loc_set_t();
 520                 val_loc_map->put(val, locations);
 521         }
 522
 523         update_loc_may_equal_map(loc, locations);
 524         locations->add(loc);
 525         // values_may_read_from->add(val);
 526 }
 527
 528 void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
 529 {
 530         if (values == NULL)
 531                 return;
 532
 533         value_set_iter * it = values->iterator();
 534         while (it->hasNext()) {
 535                 uint64_t val = it->next();
 536                 add_to_val_loc_map(val, loc);
 537         }
 538 }
 539
 540 void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 541 {
 542         loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
 543
 544         if (neighbors == NULL) {
 545                 neighbors = new loc_set_t();
 546                 loc_may_equal_map->put(new_loc, neighbors);
 547         }
 548
 549         loc_set_iter * loc_it = old_locations->iterator();
 550         while (loc_it->hasNext()) {
 551                 // new_loc: { old_locations, ... }
 552                 void * member = loc_it->next();
 553                 neighbors->add(member);
 554
 555                 // for each i in old_locations, i : { new_loc, ... }
 556                 loc_set_t * _neighbors = loc_may_equal_map->get(member);
 557                 if (_neighbors == NULL) {
 558                         _neighbors = new loc_set_t();
 559                         loc_may_equal_map->put(member, _neighbors);
 560                 }
 561                 _neighbors->add(new_loc);
 562         }
 563 }
 564
 565 void FuncNode::init_predicate_tree_position(thread_id_t tid)
 566 {
 567         uint thread_id = id_to_int(tid);
 568         if (predicate_tree_position.size() <= thread_id)
 569                 predicate_tree_position.resize(thread_id + 1);
 570
 571         predicate_tree_position[thread_id] = predicate_tree_entry;
 572 }
 573
 574 void FuncNode::unset_predicate_tree_position(thread_id_t tid)
 575 {
 576         uint thread_id = id_to_int(tid);
 577         predicate_tree_position[thread_id] = NULL;
 578 }
 579
 580 Predicate * FuncNode::get_predicate_tree_position(thread_id_t tid)
 581 {
 582         uint thread_id = id_to_int(tid);
 583         return predicate_tree_position[thread_id];
 584 }
 585
 586 void FuncNode::print_predicate_tree()
 587 {
 588         model_print("digraph function_%s {\n", func_name);
 589         predicate_tree_entry->print_pred_subtree();
 590         model_print("}\n");     // end of graph
 591 }
 592
 593 void FuncNode::print_val_loc_map()
 594 {
 595 /*
 596         value_set_iter * val_it = values_may_read_from->iterator();
 597         while (val_it->hasNext()) {
 598                 uint64_t value = val_it->next();
 599                 model_print("val %llx: ", value);
 600
 601                 loc_set_t * locations = val_loc_map->get(value);
 602                 loc_set_iter * loc_it = locations->iterator();
 603                 while (loc_it->hasNext()) {
 604                         void * location = loc_it->next();
 605                         model_print("%p ", location);
 606                 }
 607                 model_print("\n");
 608         }
 609 */
 610 }
 611
 612 /* @param tid thread id
 613  * Print the values read by the last read actions for each memory location
 614  */
 615 /*
 616 void FuncNode::print_last_read(thread_id_t tid)
 617 {
 618         ASSERT(thrd_read_map.size() > tid);
 619         read_map_t * read_map = thrd_read_map[tid];
 620
 621         mllnode<void *> * it;
 622         for (it = read_locations.begin();it != NULL;it=it->getNext()) {
 623                 if ( !read_map->contains(it->getVal()) )
 624                         break;
 625
 626                 uint64_t read_val = read_map->get(it->getVal());
 627                 model_print("last read of thread %d at %p: 0x%x\n", tid, it->getVal(), read_val);
 628         }
 629 }
 630 */