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         action_list_buffer(),
  11         predicate_tree_position()
  12 {
  13         predicate_tree_entry = new Predicate(NULL, true);
  14         predicate_tree_entry->add_predicate_expr(NOPREDICATE, NULL, true);
  15
  16         // memories that are reclaimed after each execution
  17         read_locations = new loc_set_t();
  18         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
  19         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  20         thrd_inst_act_map = new SnapVector<inst_act_map_t *>();
  21
  22         //values_may_read_from = new value_set_t();
  23 }
  24
  25 /* Reallocate snapshotted memories when new executions start */
  26 void FuncNode::set_new_exec_flag()
  27 {
  28         for (mllnode<FuncInst *> * it = inst_list.begin(); it != NULL; it = it->getNext()) {
  29                 FuncInst * inst = it->getVal();
  30                 inst->unset_location();
  31         }
  32
  33         read_locations = new loc_set_t();
  34         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
  35         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  36         thrd_inst_act_map = new SnapVector<inst_act_map_t *>();
  37
  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 rw_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_write())
 151                         rw_act_list.push_back(act);
 152
 153                 if (func_inst->is_read()) {
 154                         rw_act_list.push_back(act);
 155                         /* If func_inst may only read_from a single location, then:
 156                          *
 157                          * The first time an action reads from some location, import all the values that have
 158                          * been written to this location from ModelHistory and notify ModelHistory that this
 159                          * FuncNode may read from this location.
 160                          */
 161                         void * loc = act->get_location();
 162                         if (!read_locations->contains(loc) && func_inst->is_single_location()) {
 163                                 read_locations->add(loc);
 164                                 value_set_t * write_values = write_history->get(loc);
 165                                 add_to_val_loc_map(write_values, loc);
 166                                 history->add_to_loc_func_nodes_map(loc, this);
 167                         }
 168                 }
 169         }
 170
 171 //      model_print("function %s\n", func_name);
 172 //      print_val_loc_map();
 173
 174         update_inst_tree(&inst_list);
 175         update_predicate_tree(&rw_act_list);
 176
 177 //      print_predicate_tree();
 178 }
 179
 180 /**
 181  * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
 182  * @param inst_list A list of FuncInsts
 183  */
 184 void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
 185 {
 186         if (inst_list == NULL)
 187                 return;
 188         else if (inst_list->size() == 0)
 189                 return;
 190
 191         /* start linking */
 192         sllnode<FuncInst *>* it = inst_list->begin();
 193         sllnode<FuncInst *>* prev;
 194
 195         /* add the first instruction to the list of entry insts */
 196         FuncInst * entry_inst = it->getVal();
 197         add_entry_inst(entry_inst);
 198
 199         it = it->getNext();
 200         while (it != NULL) {
 201                 prev = it->getPrev();
 202
 203                 FuncInst * prev_inst = prev->getVal();
 204                 FuncInst * curr_inst = it->getVal();
 205
 206                 prev_inst->add_succ(curr_inst);
 207                 curr_inst->add_pred(prev_inst);
 208
 209                 it = it->getNext();
 210         }
 211 }
 212
 213 void FuncNode::update_predicate_tree(action_list_t * act_list)
 214 {
 215         if (act_list == NULL || act_list->size() == 0)
 216                 return;
 217
 218         /* map a FuncInst to the its predicate */
 219         HashTable<FuncInst *, Predicate *, uintptr_t, 0> inst_pred_map(128);
 220
 221         // number FuncInsts to detect loops
 222         HashTable<FuncInst *, uint32_t, uintptr_t, 0> inst_id_map(128);
 223         uint32_t inst_counter = 0;
 224
 225         HashTable<void *, ModelAction *, uintptr_t, 0> loc_act_map(128);
 226         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> inst_act_map(128);
 227
 228         sllnode<ModelAction *> *it = act_list->begin();
 229         Predicate * curr_pred = predicate_tree_entry;
 230         while (it != NULL) {
 231                 ModelAction * next_act = it->getVal();
 232                 FuncInst * next_inst = get_inst(next_act);
 233
 234                 SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
 235                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, &unset_predicates);
 236
 237                 // A branch with unset predicate expression is detected
 238                 if (!branch_found && unset_predicates.size() != 0) {
 239                         ASSERT(unset_predicates.size() == 1);
 240                         Predicate * one_branch = unset_predicates[0];
 241
 242                         bool amended = amend_predicate_expr(&curr_pred, next_inst, next_act);
 243                         if (amended)
 244                                 continue;
 245                         else {
 246                                 curr_pred = one_branch;
 247                                 branch_found = true;
 248                         }
 249                 }
 250
 251                 // Detect loops
 252                 if (!branch_found && inst_id_map.contains(next_inst)) {
 253                         FuncInst * curr_inst = curr_pred->get_func_inst();
 254                         uint32_t curr_id = inst_id_map.get(curr_inst);
 255                         uint32_t next_id = inst_id_map.get(next_inst);
 256
 257                         if (curr_id >= next_id) {
 258                                 Predicate * old_pred = inst_pred_map.get(next_inst);
 259                                 Predicate * back_pred = old_pred->get_parent();
 260
 261                                 curr_pred->add_backedge(back_pred);
 262                                 curr_pred = back_pred;
 263
 264                                 continue;
 265                         }
 266                 }
 267
 268                 // Generate new branches
 269                 if (!branch_found) {
 270                         SnapVector<struct half_pred_expr *> half_pred_expressions;
 271                         infer_predicates(next_inst, next_act, &loc_act_map, &half_pred_expressions);
 272                         generate_predicates(&curr_pred, next_inst, &half_pred_expressions);
 273                         continue;
 274                 }
 275
 276                 inst_pred_map.put(next_inst, curr_pred);
 277                 if (!inst_id_map.contains(next_inst))
 278                         inst_id_map.put(next_inst, inst_counter++);
 279
 280                 loc_act_map.put(next_act->get_location(), next_act);
 281                 inst_act_map.put(next_inst, next_act);
 282                 it = it->getNext();
 283         }
 284 }
 285
 286 /* Given curr_pred and next_inst, find the branch following curr_pred that
 287  * contains next_inst and the correct predicate.
 288  * @return true if branch found, false otherwise.
 289  */
 290 bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act,
 291         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> * inst_act_map,
 292         SnapVector<Predicate *> * unset_predicates)
 293 {
 294         /* check if a branch with func_inst and corresponding predicate exists */
 295         bool branch_found = false;
 296         ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
 297         for (uint i = 0; i < branches->size(); i++) {
 298                 Predicate * branch = (*branches)[i];
 299                 if (branch->get_func_inst() != next_inst)
 300                         continue;
 301
 302                 /* check against predicate expressions */
 303                 bool predicate_correct = true;
 304                 PredExprSet * pred_expressions = branch->get_pred_expressions();
 305                 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
 306
 307                 if (pred_expressions->getSize() == 0) {
 308                         predicate_correct = false;
 309                         unset_predicates->push_back(branch);
 310                 }
 311
 312                 while (pred_expr_it->hasNext()) {
 313                         pred_expr * pred_expression = pred_expr_it->next();
 314                         uint64_t last_read, next_read;
 315                         bool equality;
 316
 317                         switch(pred_expression->token) {
 318                                 case NOPREDICATE:
 319                                         predicate_correct = true;
 320                                         break;
 321                                 case EQUALITY:
 322                                         FuncInst * to_be_compared;
 323                                         ModelAction * last_act;
 324
 325                                         to_be_compared = pred_expression->func_inst;
 326                                         last_act = inst_act_map->get(to_be_compared);
 327
 328                                         last_read = last_act->get_reads_from_value();
 329                                         next_read = next_act->get_reads_from_value();
 330                                         equality = (last_read == next_read);
 331                                         if (equality != pred_expression->value)
 332                                                 predicate_correct = false;
 333
 334                                         break;
 335                                 case NULLITY:
 336                                         next_read = next_act->get_reads_from_value();
 337                                         equality = ((void*)next_read == NULL);
 338                                         if (equality != pred_expression->value)
 339                                                 predicate_correct = false;
 340                                         break;
 341                                 default:
 342                                         predicate_correct = false;
 343                                         model_print("unkown predicate token\n");
 344                                         break;
 345                         }
 346                 }
 347
 348                 if (predicate_correct) {
 349                         *curr_pred = branch;
 350                         branch_found = true;
 351                         break;
 352                 }
 353         }
 354
 355         return branch_found;
 356 }
 357
 358 void FuncNode::infer_predicates(FuncInst * next_inst, ModelAction * next_act,
 359         HashTable<void *, ModelAction *, uintptr_t, 0> * loc_act_map,
 360         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 361 {
 362         void * loc = next_act->get_location();
 363
 364         if (next_inst->is_read()) {
 365                 if ( loc_act_map->contains(loc) ) {
 366                         ModelAction * last_act = loc_act_map->get(loc);
 367                         FuncInst * last_inst = get_inst(last_act);
 368                         struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 369                         half_pred_expressions->push_back(expression);
 370                 } else if ( next_inst->is_single_location() ){
 371                         loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
 372
 373                         if (loc_may_equal != NULL) {
 374                                 loc_set_iter * loc_it = loc_may_equal->iterator();
 375                                 while (loc_it->hasNext()) {
 376                                         void * neighbor = loc_it->next();
 377                                         if (loc_act_map->contains(neighbor)) {
 378                                                 ModelAction * last_act = loc_act_map->get(neighbor);
 379                                                 FuncInst * last_inst = get_inst(last_act);
 380
 381                                                 struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 382                                                 half_pred_expressions->push_back(expression);
 383                                         }
 384                                 }
 385                         }
 386                 } else {
 387                         // next_inst is not single location
 388                         uint64_t read_val = next_act->get_reads_from_value();
 389
 390                         // only infer NULLITY predicate when it is actually NULL.
 391                         if ( (void*)read_val == NULL) {
 392                                 struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
 393                                 half_pred_expressions->push_back(expression);
 394                         }
 395                 }
 396         } else {
 397                 // TODO: when next_act is a write action, do anything?
 398         }
 399 }
 400
 401 /* Able to generate complex predicates when there are multiple predciate expressions */
 402 void FuncNode::generate_predicates(Predicate ** curr_pred, FuncInst * next_inst,
 403         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 404 {
 405         if (half_pred_expressions->size() == 0) {
 406                 Predicate * new_pred = new Predicate(next_inst);
 407                 (*curr_pred)->add_child(new_pred);
 408                 new_pred->set_parent(*curr_pred);
 409
 410                 /* entry predicates and predicates containing write actions
 411                  * have no predicate expressions */
 412                 if ( (*curr_pred)->is_entry_predicate() )
 413                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 414                 else if (next_inst->is_write())
 415                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 416
 417                 return;
 418         }
 419
 420         SnapVector<Predicate *> predicates;
 421
 422         struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
 423         predicates.push_back(new Predicate(next_inst));
 424         predicates.push_back(new Predicate(next_inst));
 425
 426         predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 427         predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 428
 429         for (uint i = 1; i < half_pred_expressions->size(); i++) {
 430                 half_expr = (*half_pred_expressions)[i];
 431
 432                 uint old_size = predicates.size();
 433                 for (uint j = 0; j < old_size; j++) {
 434                         Predicate * pred = predicates[j];
 435                         Predicate * new_pred = new Predicate(next_inst);
 436                         new_pred->copy_predicate_expr(pred);
 437
 438                         pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 439                         new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 440
 441                         predicates.push_back(new_pred);
 442                 }
 443         }
 444
 445         for (uint i = 0; i < predicates.size(); i++) {
 446                 Predicate * pred= predicates[i];
 447                 (*curr_pred)->add_child(pred);
 448                 pred->set_parent(*curr_pred);
 449         }
 450 }
 451
 452 /* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
 453 bool FuncNode::amend_predicate_expr(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act)
 454 {
 455         // there should only be only child
 456         Predicate * unset_pred = (*curr_pred)->get_children()->back();
 457         uint64_t read_val = next_act->get_reads_from_value();
 458
 459         // only generate NULLITY predicate when it is actually NULL.
 460         if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
 461                 Predicate * new_pred = new Predicate(next_inst);
 462
 463                 (*curr_pred)->add_child(new_pred);
 464                 new_pred->set_parent(*curr_pred);
 465
 466                 unset_pred->add_predicate_expr(NULLITY, NULL, false);
 467                 new_pred->add_predicate_expr(NULLITY, NULL, true);
 468
 469                 return true;
 470         }
 471
 472         return false;
 473 }
 474
 475 void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 476 {
 477         loc_set_t * locations = val_loc_map->get(val);
 478
 479         if (locations == NULL) {
 480                 locations = new loc_set_t();
 481                 val_loc_map->put(val, locations);
 482         }
 483
 484         update_loc_may_equal_map(loc, locations);
 485         locations->add(loc);
 486         // values_may_read_from->add(val);
 487 }
 488
 489 void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
 490 {
 491         if (values == NULL)
 492                 return;
 493
 494         value_set_iter * it = values->iterator();
 495         while (it->hasNext()) {
 496                 uint64_t val = it->next();
 497                 add_to_val_loc_map(val, loc);
 498         }
 499 }
 500
 501 void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 502 {
 503         if ( old_locations->contains(new_loc) )
 504                 return;
 505
 506         loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
 507
 508         if (neighbors == NULL) {
 509                 neighbors = new loc_set_t();
 510                 loc_may_equal_map->put(new_loc, neighbors);
 511         }
 512
 513         loc_set_iter * loc_it = old_locations->iterator();
 514         while (loc_it->hasNext()) {
 515                 // new_loc: { old_locations, ... }
 516                 void * member = loc_it->next();
 517                 neighbors->add(member);
 518
 519                 // for each i in old_locations, i : { new_loc, ... }
 520                 loc_set_t * _neighbors = loc_may_equal_map->get(member);
 521                 if (_neighbors == NULL) {
 522                         _neighbors = new loc_set_t();
 523                         loc_may_equal_map->put(member, _neighbors);
 524                 }
 525                 _neighbors->add(new_loc);
 526         }
 527 }
 528
 529 void FuncNode::init_predicate_tree_position(thread_id_t tid)
 530 {
 531         int thread_id = id_to_int(tid);
 532         if (predicate_tree_position.size() <= (uint) thread_id)
 533                 predicate_tree_position.resize(thread_id + 1);
 534
 535         predicate_tree_position[thread_id] = predicate_tree_entry;
 536 }
 537
 538 void FuncNode::set_predicate_tree_position(thread_id_t tid, Predicate * pred)
 539 {
 540         int thread_id = id_to_int(tid);
 541         predicate_tree_position[thread_id] = pred;
 542 }
 543
 544 Predicate * FuncNode::get_predicate_tree_position(thread_id_t tid)
 545 {
 546         int thread_id = id_to_int(tid);
 547         return predicate_tree_position[thread_id];
 548 }
 549
 550 void FuncNode::init_inst_act_map(thread_id_t tid)
 551 {
 552         int thread_id = id_to_int(tid);
 553         uint old_size = thrd_inst_act_map->size();
 554
 555         if (thrd_inst_act_map->size() <= (uint) thread_id) {
 556                 uint new_size = thread_id + 1;
 557                 thrd_inst_act_map->resize(new_size);
 558
 559                 for (uint i = old_size; i < new_size; i++)
 560                         (*thrd_inst_act_map)[i] = new inst_act_map_t(128);
 561         }
 562 }
 563
 564 void FuncNode::reset_inst_act_map(thread_id_t tid)
 565 {
 566         int thread_id = id_to_int(tid);
 567         inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
 568         map->reset();
 569 }
 570
 571 void FuncNode::update_inst_act_map(thread_id_t tid, ModelAction * read_act)
 572 {
 573         int thread_id = id_to_int(tid);
 574         inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
 575         FuncInst * read_inst = get_inst(read_act);
 576         map->put(read_inst, read_act);
 577 }
 578
 579 inst_act_map_t * FuncNode::get_inst_act_map(thread_id_t tid)
 580 {
 581         int thread_id = id_to_int(tid);
 582         return (*thrd_inst_act_map)[thread_id];
 583 }
 584
 585 void FuncNode::print_predicate_tree()
 586 {
 587         model_print("digraph function_%s {\n", func_name);
 588         predicate_tree_entry->print_pred_subtree();
 589         model_print("}\n");     // end of graph
 590 }
 591
 592 void FuncNode::print_val_loc_map()
 593 {
 594 /*
 595         value_set_iter * val_it = values_may_read_from->iterator();
 596         while (val_it->hasNext()) {
 597                 uint64_t value = val_it->next();
 598                 model_print("val %llx: ", value);
 599
 600                 loc_set_t * locations = val_loc_map->get(value);
 601                 loc_set_iter * loc_it = locations->iterator();
 602                 while (loc_it->hasNext()) {
 603                         void * location = loc_it->next();
 604                         model_print("%p ", location);
 605                 }
 606                 model_print("\n");
 607         }
 608 */
 609 }