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                         /* If func_inst may only read_from a single location, then:
 154                          *
 155                          * The first time an action reads from some location, import all the values that have
 156                          * been written to this location from ModelHistory and notify ModelHistory that this
 157                          * FuncNode may read from this location
 158                          */
 159                         void * loc = act->get_location();
 160                         if (!read_locations->contains(loc) && func_inst->is_single_location()) {
 161                                 read_locations->add(loc);
 162                                 value_set_t * write_values = write_history->get(loc);
 163                                 add_to_val_loc_map(write_values, loc);
 164                                 history->add_to_loc_func_nodes_map(loc, this);
 165                         }
 166                 }
 167         }
 168
 169 //      model_print("function %s\n", func_name);
 170 //      print_val_loc_map();
 171
 172         update_inst_tree(&inst_list);
 173         update_predicate_tree(&read_act_list);
 174
 175 //      print_predicate_tree();
 176 }
 177
 178 /**
 179  * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
 180  * @param inst_list A list of FuncInsts
 181  */
 182 void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
 183 {
 184         if (inst_list == NULL)
 185                 return;
 186         else if (inst_list->size() == 0)
 187                 return;
 188
 189         /* start linking */
 190         sllnode<FuncInst *>* it = inst_list->begin();
 191         sllnode<FuncInst *>* prev;
 192
 193         /* add the first instruction to the list of entry insts */
 194         FuncInst * entry_inst = it->getVal();
 195         add_entry_inst(entry_inst);
 196
 197         it = it->getNext();
 198         while (it != NULL) {
 199                 prev = it->getPrev();
 200
 201                 FuncInst * prev_inst = prev->getVal();
 202                 FuncInst * curr_inst = it->getVal();
 203
 204                 prev_inst->add_succ(curr_inst);
 205                 curr_inst->add_pred(prev_inst);
 206
 207                 it = it->getNext();
 208         }
 209 }
 210
 211 /* @param tid thread id
 212  * Store the values read by atomic read actions into thrd_read_map */
 213 void FuncNode::store_read(ModelAction * act, thread_id_t tid)
 214 {
 215 /*
 216         ASSERT(act);
 217
 218         void * location = act->get_location();
 219         uint64_t read_from_val = act->get_reads_from_value();
 220
 221         // resize and initialize
 222         uint32_t old_size = thrd_read_map.size();
 223         if (old_size <= tid) {
 224                 thrd_read_map.resize(tid + 1);
 225                 for (uint32_t i = old_size; i < tid + 1;i++)
 226                         thrd_read_map[i] = new read_map_t();
 227         }
 228
 229         read_map_t * read_map = thrd_read_map[tid];
 230         read_map->put(location, read_from_val);
 231 */
 232 }
 233
 234 uint64_t FuncNode::query_last_read(void * location, thread_id_t tid)
 235 {
 236 /*
 237         if (thrd_read_map.size() <= tid)
 238                 return VALUE_NONE;
 239
 240         read_map_t * read_map = thrd_read_map[tid];
 241
 242         // last read value not found
 243         if ( !read_map->contains(location) )
 244                 return VALUE_NONE;
 245
 246         uint64_t read_val = read_map->get(location);
 247         return read_val;
 248 */
 249 }
 250
 251 /* @param tid thread id
 252  * Reset read map for a thread. This function shall only be called
 253  * when a thread exits a function
 254  */
 255 void FuncNode::clear_read_map(thread_id_t tid)
 256 {
 257 /*
 258         if (thrd_read_map.size() <= tid)
 259                 return;
 260
 261         thrd_read_map[tid]->reset();
 262 */
 263 }
 264
 265 void FuncNode::update_predicate_tree(action_list_t * act_list)
 266 {
 267         if (act_list == NULL || act_list->size() == 0)
 268                 return;
 269
 270         /* map a FuncInst to the its predicate */
 271         HashTable<FuncInst *, Predicate *, uintptr_t, 0> inst_pred_map(128);
 272
 273         // number FuncInsts to detect loops
 274         HashTable<FuncInst *, uint32_t, uintptr_t, 0> inst_id_map(128);
 275         uint32_t inst_counter = 0;
 276
 277         HashTable<void *, ModelAction *, uintptr_t, 0> loc_act_map(128);
 278         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> inst_act_map(128);
 279
 280         sllnode<ModelAction *> *it = act_list->begin();
 281         Predicate * curr_pred = predicate_tree_entry;
 282         while (it != NULL) {
 283                 ModelAction * next_act = it->getVal();
 284                 FuncInst * next_inst = get_inst(next_act);
 285
 286                 SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
 287                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, &unset_predicates);
 288
 289                 // no predicate expressions
 290                 if (!branch_found && unset_predicates.size() != 0) {
 291                         ASSERT(unset_predicates.size() == 1);
 292                         Predicate * one_branch = unset_predicates[0];
 293
 294                         bool amended = amend_predicate_expr(&curr_pred, next_inst, next_act);
 295                         if (amended)
 296                                 continue;
 297                         else {
 298                                 curr_pred = one_branch;
 299                                 branch_found = true;
 300                         }
 301                 }
 302
 303                 // detect loops
 304                 if (!branch_found && inst_id_map.contains(next_inst)) {
 305                         FuncInst * curr_inst = curr_pred->get_func_inst();
 306                         uint32_t curr_id = inst_id_map.get(curr_inst);
 307                         uint32_t next_id = inst_id_map.get(next_inst);
 308
 309                         if (curr_id >= next_id) {
 310                                 Predicate * old_pred = inst_pred_map.get(next_inst);
 311                                 Predicate * back_pred = old_pred->get_parent();
 312
 313                                 curr_pred->add_backedge(back_pred);
 314                                 curr_pred = back_pred;
 315
 316                                 continue;
 317                         }
 318                 }
 319
 320                 // generate new branches
 321                 if (!branch_found) {
 322                         SnapVector<struct half_pred_expr *> half_pred_expressions;
 323                         void * loc = next_act->get_location();
 324
 325                         if ( loc_act_map.contains(loc) ) {
 326                                 ModelAction * last_act = loc_act_map.get(loc);
 327                                 FuncInst * last_inst = get_inst(last_act);
 328                                 struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 329                                 half_pred_expressions.push_back(expression);
 330                         } else if ( next_inst->is_single_location() ){
 331                                 loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
 332
 333                                 if (loc_may_equal != NULL) {
 334                                         loc_set_iter * loc_it = loc_may_equal->iterator();
 335                                         while (loc_it->hasNext()) {
 336                                                 void * neighbor = loc_it->next();
 337                                                 if (loc_act_map.contains(neighbor)) {
 338                                                         ModelAction * last_act = loc_act_map.get(neighbor);
 339                                                         FuncInst * last_inst = get_inst(last_act);
 340
 341                                                         struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 342                                                         half_pred_expressions.push_back(expression);
 343                                                 }
 344                                         }
 345                                 }
 346                         } else {
 347                                 // next_inst is not single location
 348                                 uint64_t read_val = next_act->get_reads_from_value();
 349
 350                                 // only generate NULLITY predicate when it is actually NULL.
 351                                 if ( (void*)read_val == NULL) {
 352                                         struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
 353                                         half_pred_expressions.push_back(expression);
 354                                 }
 355                         }
 356
 357                         if (half_pred_expressions.size() == 0) {
 358                                 // no predicate needs to be generated
 359                                 Predicate * new_pred = new Predicate(next_inst);
 360                                 curr_pred->add_child(new_pred);
 361                                 new_pred->set_parent(curr_pred);
 362
 363                                 if (curr_pred->is_entry_predicate())
 364                                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 365
 366                                 curr_pred = new_pred;
 367                         } else {
 368                                 generate_predicate(&curr_pred, next_inst, &half_pred_expressions);
 369                                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, NULL);
 370                                 ASSERT(branch_found);
 371                         }
 372                 }
 373
 374                 inst_pred_map.put(next_inst, curr_pred);
 375                 if (!inst_id_map.contains(next_inst))
 376                         inst_id_map.put(next_inst, inst_counter++);
 377
 378                 loc_act_map.put(next_act->get_location(), next_act);
 379                 inst_act_map.put(next_inst, next_act);
 380                 it = it->getNext();
 381         }
 382 }
 383
 384 /* Given curr_pred and next_inst, find the branch following curr_pred that
 385  * contains next_inst and the correct predicate.
 386  * @return true if branch found, false otherwise.
 387  */
 388 bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act,
 389         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> * inst_act_map,
 390         SnapVector<Predicate *> * unset_predicates)
 391 {
 392         /* check if a branch with func_inst and corresponding predicate exists */
 393         bool branch_found = false;
 394         ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
 395         for (uint i = 0; i < branches->size(); i++) {
 396                 Predicate * branch = (*branches)[i];
 397                 if (branch->get_func_inst() != next_inst)
 398                         continue;
 399
 400                 /* check against predicate expressions */
 401                 bool predicate_correct = true;
 402                 PredExprSet * pred_expressions = branch->get_pred_expressions();
 403                 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
 404
 405                 if (pred_expressions->getSize() == 0) {
 406                         predicate_correct = false;
 407                         unset_predicates->push_back(branch);
 408                 }
 409
 410                 while (pred_expr_it->hasNext()) {
 411                         pred_expr * pred_expression = pred_expr_it->next();
 412                         uint64_t last_read, next_read;
 413                         bool equality;
 414
 415                         switch(pred_expression->token) {
 416                                 case NOPREDICATE:
 417                                         predicate_correct = true;
 418                                         break;
 419                                 case EQUALITY:
 420                                         FuncInst * to_be_compared;
 421                                         ModelAction * last_act;
 422
 423                                         to_be_compared = pred_expression->func_inst;
 424                                         last_act = inst_act_map->get(to_be_compared);
 425
 426                                         last_read = last_act->get_reads_from_value();
 427                                         next_read = next_act->get_reads_from_value();
 428                                         equality = (last_read == next_read);
 429                                         if (equality != pred_expression->value)
 430                                                 predicate_correct = false;
 431
 432                                         break;
 433                                 case NULLITY:
 434                                         next_read = next_act->get_reads_from_value();
 435                                         equality = ((void*)next_read == NULL);
 436                                         if (equality != pred_expression->value)
 437                                                 predicate_correct = false;
 438                                         break;
 439                                 default:
 440                                         predicate_correct = false;
 441                                         model_print("unkown predicate token\n");
 442                                         break;
 443                         }
 444                 }
 445
 446                 if (predicate_correct) {
 447                         *curr_pred = branch;
 448                         branch_found = true;
 449                         break;
 450                 }
 451         }
 452
 453         return branch_found;
 454 }
 455
 456 /* Able to generate complex predicates when there are multiple predciate expressions */
 457 void FuncNode::generate_predicate(Predicate ** curr_pred, FuncInst * next_inst,
 458         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 459 {
 460         ASSERT(half_pred_expressions->size() != 0);
 461         SnapVector<Predicate *> predicates;
 462
 463         struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
 464         predicates.push_back(new Predicate(next_inst));
 465         predicates.push_back(new Predicate(next_inst));
 466
 467         predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 468         predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 469
 470         for (uint i = 1; i < half_pred_expressions->size(); i++) {
 471                 half_expr = (*half_pred_expressions)[i];
 472
 473                 uint old_size = predicates.size();
 474                 for (uint j = 0; j < old_size; j++) {
 475                         Predicate * pred = predicates[j];
 476                         Predicate * new_pred = new Predicate(next_inst);
 477                         new_pred->copy_predicate_expr(pred);
 478
 479                         pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 480                         new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 481
 482                         predicates.push_back(new_pred);
 483                 }
 484         }
 485
 486         for (uint i = 0; i < predicates.size(); i++) {
 487                 Predicate * pred= predicates[i];
 488                 (*curr_pred)->add_child(pred);
 489                 pred->set_parent(*curr_pred);
 490         }
 491 }
 492
 493 /* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
 494 bool FuncNode::amend_predicate_expr(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act)
 495 {
 496         // there should only be only child
 497         Predicate * unset_pred = (*curr_pred)->get_children()->back();
 498         uint64_t read_val = next_act->get_reads_from_value();
 499
 500         // only generate NULLITY predicate when it is actually NULL.
 501         if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
 502                 Predicate * new_pred = new Predicate(next_inst);
 503
 504                 (*curr_pred)->add_child(new_pred);
 505                 new_pred->set_parent(*curr_pred);
 506
 507                 unset_pred->add_predicate_expr(NULLITY, NULL, false);
 508                 new_pred->add_predicate_expr(NULLITY, NULL, true);
 509
 510                 return true;
 511         }
 512
 513         return false;
 514 }
 515
 516 void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 517 {
 518         loc_set_t * locations = val_loc_map->get(val);
 519
 520         if (locations == NULL) {
 521                 locations = new loc_set_t();
 522                 val_loc_map->put(val, locations);
 523         }
 524
 525         update_loc_may_equal_map(loc, locations);
 526         locations->add(loc);
 527         // values_may_read_from->add(val);
 528 }
 529
 530 void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
 531 {
 532         if (values == NULL)
 533                 return;
 534
 535         value_set_iter * it = values->iterator();
 536         while (it->hasNext()) {
 537                 uint64_t val = it->next();
 538                 add_to_val_loc_map(val, loc);
 539         }
 540 }
 541
 542 void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 543 {
 544         if ( old_locations->contains(new_loc) )
 545                 return;
 546
 547         loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
 548
 549         if (neighbors == NULL) {
 550                 neighbors = new loc_set_t();
 551                 loc_may_equal_map->put(new_loc, neighbors);
 552         }
 553
 554         loc_set_iter * loc_it = old_locations->iterator();
 555         while (loc_it->hasNext()) {
 556                 // new_loc: { old_locations, ... }
 557                 void * member = loc_it->next();
 558                 neighbors->add(member);
 559
 560                 // for each i in old_locations, i : { new_loc, ... }
 561                 loc_set_t * _neighbors = loc_may_equal_map->get(member);
 562                 if (_neighbors == NULL) {
 563                         _neighbors = new loc_set_t();
 564                         loc_may_equal_map->put(member, _neighbors);
 565                 }
 566                 _neighbors->add(new_loc);
 567         }
 568 }
 569
 570 void FuncNode::init_predicate_tree_position(thread_id_t tid)
 571 {
 572         uint thread_id = id_to_int(tid);
 573         if (predicate_tree_position.size() <= thread_id)
 574                 predicate_tree_position.resize(thread_id + 1);
 575
 576         predicate_tree_position[thread_id] = predicate_tree_entry;
 577 }
 578
 579 void FuncNode::unset_predicate_tree_position(thread_id_t tid)
 580 {
 581         uint thread_id = id_to_int(tid);
 582         predicate_tree_position[thread_id] = NULL;
 583 }
 584
 585 Predicate * FuncNode::get_predicate_tree_position(thread_id_t tid)
 586 {
 587         uint thread_id = id_to_int(tid);
 588         return predicate_tree_position[thread_id];
 589 }
 590
 591 void FuncNode::print_predicate_tree()
 592 {
 593         model_print("digraph function_%s {\n", func_name);
 594         predicate_tree_entry->print_pred_subtree();
 595         model_print("}\n");     // end of graph
 596 }
 597
 598 void FuncNode::print_val_loc_map()
 599 {
 600 /*
 601         value_set_iter * val_it = values_may_read_from->iterator();
 602         while (val_it->hasNext()) {
 603                 uint64_t value = val_it->next();
 604                 model_print("val %llx: ", value);
 605
 606                 loc_set_t * locations = val_loc_map->get(value);
 607                 loc_set_iter * loc_it = locations->iterator();
 608                 while (loc_it->hasNext()) {
 609                         void * location = loc_it->next();
 610                         model_print("%p ", location);
 611                 }
 612                 model_print("\n");
 613         }
 614 */
 615 }
 616
 617 /* @param tid thread id
 618  * Print the values read by the last read actions for each memory location
 619  */
 620 /*
 621 void FuncNode::print_last_read(thread_id_t tid)
 622 {
 623         ASSERT(thrd_read_map.size() > tid);
 624         read_map_t * read_map = thrd_read_map[tid];
 625
 626         mllnode<void *> * it;
 627         for (it = read_locations.begin();it != NULL;it=it->getNext()) {
 628                 if ( !read_map->contains(it->getVal()) )
 629                         break;
 630
 631                 uint64_t read_val = read_map->get(it->getVal());
 632                 model_print("last read of thread %d at %p: 0x%x\n", tid, it->getVal(), read_val);
 633         }
 634 }
 635 */