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