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         predicate_tree_position()
  11 {
  12         predicate_tree_entry = new Predicate(NULL, true);
  13         predicate_tree_entry->add_predicate_expr(NOPREDICATE, NULL, true);
  14
  15         // memories that are reclaimed after each execution
  16         action_list_buffer = new SnapList<action_list_t *>();
  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         action_list_buffer = new SnapList<action_list_t *>();
  34         read_locations = new loc_set_t();
  35         val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
  36         loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
  37         thrd_inst_act_map = new SnapVector<inst_act_map_t *>();
  38
  39         //values_may_read_from = new value_set_t();
  40 }
  41
  42 /* Check whether FuncInst with the same type, position, and location
  43  * as act has been added to func_inst_map or not. If not, add it.
  44  *
  45  * Note: currently, actions with the same position are filtered out by process_action,
  46  * so the collision list of FuncInst is not used. May remove it later.
  47  */
  48 void FuncNode::add_inst(ModelAction *act)
  49 {
  50         ASSERT(act);
  51         const char * position = act->get_position();
  52
  53         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  54          * actions are not tagged with their source line numbers
  55          */
  56         if (position == NULL)
  57                 return;
  58
  59         if ( func_inst_map.contains(position) ) {
  60                 FuncInst * inst = func_inst_map.get(position);
  61
  62                 ASSERT(inst->get_type() == act->get_type());
  63
  64                 // locations are set to NULL when new executions start
  65                 if (inst->get_location() == NULL)
  66                         inst->set_location(act->get_location());
  67
  68                 if (inst->get_location() != act->get_location())
  69                         inst->not_single_location();
  70
  71                 return;
  72         }
  73
  74         FuncInst * func_inst = new FuncInst(act, this);
  75
  76         func_inst_map.put(position, func_inst);
  77         inst_list.push_back(func_inst);
  78 }
  79
  80 /* Get the FuncInst with the same type, position, and location
  81  * as act
  82  *
  83  * @return FuncInst with the same type, position, and location as act */
  84 FuncInst * FuncNode::get_inst(ModelAction *act)
  85 {
  86         ASSERT(act);
  87         const char * position = act->get_position();
  88
  89         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  90          * actions are not tagged with their source line numbers
  91          */
  92         if (position == NULL)
  93                 return NULL;
  94
  95         FuncInst * inst = func_inst_map.get(position);
  96         if (inst == NULL)
  97                 return NULL;
  98
  99         action_type inst_type = inst->get_type();
 100         action_type act_type = act->get_type();
 101
 102         // else if branch: an RMWRCAS action is converted to a RMW or READ action
 103         if (inst_type == act_type)
 104                 return inst;
 105         else if (inst_type == ATOMIC_RMWRCAS &&
 106                         (act_type == ATOMIC_RMW || act_type == ATOMIC_READ))
 107                 return inst;
 108
 109         return NULL;
 110 }
 111
 112
 113 void FuncNode::add_entry_inst(FuncInst * inst)
 114 {
 115         if (inst == NULL)
 116                 return;
 117
 118         mllnode<FuncInst *> * it;
 119         for (it = entry_insts.begin(); it != NULL; it = it->getNext()) {
 120                 if (inst == it->getVal())
 121                         return;
 122         }
 123
 124         entry_insts.push_back(inst);
 125 }
 126
 127 /**
 128  * @brief Convert ModelAdtion list to FuncInst list
 129  * @param act_list A list of ModelActions
 130  */
 131 void FuncNode::update_tree(action_list_t * act_list)
 132 {
 133         if (act_list == NULL || act_list->size() == 0)
 134                 return;
 135
 136         HashTable<void *, value_set_t *, uintptr_t, 4> * write_history = history->getWriteHistory();
 137
 138         /* build inst_list from act_list for later processing */
 139         func_inst_list_t inst_list;
 140         action_list_t rw_act_list;
 141
 142         for (sllnode<ModelAction *> * it = act_list->begin(); it != NULL; it = it->getNext()) {
 143                 ModelAction * act = it->getVal();
 144                 FuncInst * func_inst = get_inst(act);
 145
 146                 if (func_inst == NULL)
 147                         continue;
 148
 149                 inst_list.push_back(func_inst);
 150
 151                 /* NOTE: for rmw actions, func_inst and act may have different
 152                  * action types because of action type conversion in ModelExecution
 153                  * func_inst->is_write() <==> pure writes (excluding rmw) */
 154                 if (func_inst->is_write()) {
 155                         // model_print("write detected\n");
 156                         rw_act_list.push_back(act);
 157                 }
 158
 159                 /* func_inst->is_read() <==> read + rmw */
 160                 if (func_inst->is_read()) {
 161                         rw_act_list.push_back(act);
 162                         /* If func_inst may only read_from a single location, then:
 163                          *
 164                          * The first time an action reads from some location,
 165                          * import all the values that have been written to this
 166                          * location from ModelHistory and notify ModelHistory
 167                          * that this FuncNode may read from this location.
 168                          */
 169                         void * loc = act->get_location();
 170                         if (!read_locations->contains(loc) && func_inst->is_single_location()) {
 171                                 read_locations->add(loc);
 172                                 value_set_t * write_values = write_history->get(loc);
 173                                 add_to_val_loc_map(write_values, loc);
 174                                 history->add_to_loc_func_nodes_map(loc, this);
 175                         }
 176                 }
 177         }
 178
 179 //      model_print("function %s\n", func_name);
 180 //      print_val_loc_map();
 181
 182         update_inst_tree(&inst_list);
 183         update_predicate_tree(&rw_act_list);
 184
 185 //      print_predicate_tree();
 186 }
 187
 188 /**
 189  * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
 190  * @param inst_list A list of FuncInsts
 191  */
 192 void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
 193 {
 194         if (inst_list == NULL)
 195                 return;
 196         else if (inst_list->size() == 0)
 197                 return;
 198
 199         /* start linking */
 200         sllnode<FuncInst *>* it = inst_list->begin();
 201         sllnode<FuncInst *>* prev;
 202
 203         /* add the first instruction to the list of entry insts */
 204         FuncInst * entry_inst = it->getVal();
 205         add_entry_inst(entry_inst);
 206
 207         it = it->getNext();
 208         while (it != NULL) {
 209                 prev = it->getPrev();
 210
 211                 FuncInst * prev_inst = prev->getVal();
 212                 FuncInst * curr_inst = it->getVal();
 213
 214                 prev_inst->add_succ(curr_inst);
 215                 curr_inst->add_pred(prev_inst);
 216
 217                 it = it->getNext();
 218         }
 219 }
 220
 221 void FuncNode::update_predicate_tree(action_list_t * act_list)
 222 {
 223         if (act_list == NULL || act_list->size() == 0)
 224                 return;
 225
 226         /* map a FuncInst to the its predicate */
 227         HashTable<FuncInst *, Predicate *, uintptr_t, 0> inst_pred_map(128);
 228
 229         // number FuncInsts to detect loops
 230         HashTable<FuncInst *, uint32_t, uintptr_t, 0> inst_id_map(128);
 231         uint32_t inst_counter = 0;
 232
 233         HashTable<void *, ModelAction *, uintptr_t, 0> loc_act_map(128);
 234         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> inst_act_map(128);
 235
 236         sllnode<ModelAction *> *it = act_list->begin();
 237         Predicate * curr_pred = predicate_tree_entry;
 238         while (it != NULL) {
 239                 ModelAction * next_act = it->getVal();
 240                 FuncInst * next_inst = get_inst(next_act);
 241
 242                 SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
 243                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, &unset_predicates);
 244
 245                 // A branch with unset predicate expression is detected
 246                 if (!branch_found && unset_predicates.size() != 0) {
 247                         ASSERT(unset_predicates.size() == 1);
 248                         Predicate * one_branch = unset_predicates[0];
 249
 250                         bool amended = amend_predicate_expr(&curr_pred, next_inst, next_act);
 251                         if (amended)
 252                                 continue;
 253                         else {
 254                                 curr_pred = one_branch;
 255                                 branch_found = true;
 256                         }
 257                 }
 258
 259                 // Detect loops
 260                 if (!branch_found && inst_id_map.contains(next_inst)) {
 261                         FuncInst * curr_inst = curr_pred->get_func_inst();
 262                         uint32_t curr_id = inst_id_map.get(curr_inst);
 263                         uint32_t next_id = inst_id_map.get(next_inst);
 264
 265                         if (curr_id >= next_id) {
 266                                 Predicate * old_pred = inst_pred_map.get(next_inst);
 267                                 Predicate * back_pred = old_pred->get_parent();
 268
 269                                 curr_pred->add_backedge(back_pred);
 270                                 curr_pred = back_pred;
 271
 272                                 continue;
 273                         }
 274                 }
 275
 276                 // Generate new branches
 277                 if (!branch_found) {
 278                         SnapVector<struct half_pred_expr *> half_pred_expressions;
 279                         infer_predicates(next_inst, next_act, &loc_act_map, &half_pred_expressions);
 280                         generate_predicates(&curr_pred, next_inst, &half_pred_expressions);
 281                         continue;
 282                 }
 283
 284                 if (next_act->is_write())
 285                         curr_pred->set_write(true);
 286
 287                 inst_pred_map.put(next_inst, curr_pred);
 288                 if (!inst_id_map.contains(next_inst))
 289                         inst_id_map.put(next_inst, inst_counter++);
 290
 291                 loc_act_map.put(next_act->get_location(), next_act);
 292                 inst_act_map.put(next_inst, next_act);
 293                 it = it->getNext();
 294         }
 295 }
 296
 297 /* Given curr_pred and next_inst, find the branch following curr_pred that
 298  * contains next_inst and the correct predicate.
 299  * @return true if branch found, false otherwise.
 300  */
 301 bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act,
 302         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> * inst_act_map,
 303         SnapVector<Predicate *> * unset_predicates)
 304 {
 305         /* check if a branch with func_inst and corresponding predicate exists */
 306         bool branch_found = false;
 307         ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
 308         for (uint i = 0; i < branches->size(); i++) {
 309                 Predicate * branch = (*branches)[i];
 310                 if (branch->get_func_inst() != next_inst)
 311                         continue;
 312
 313                 /* check against predicate expressions */
 314                 bool predicate_correct = true;
 315                 PredExprSet * pred_expressions = branch->get_pred_expressions();
 316                 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
 317
 318                 /* Only read and rmw actions my have unset predicate expressions */
 319                 if (pred_expressions->getSize() == 0) {
 320                         predicate_correct = false;
 321                         unset_predicates->push_back(branch);
 322                 }
 323
 324                 while (pred_expr_it->hasNext()) {
 325                         pred_expr * pred_expression = pred_expr_it->next();
 326                         uint64_t last_read, next_read;
 327                         bool equality;
 328
 329                         switch(pred_expression->token) {
 330                                 case NOPREDICATE:
 331                                         predicate_correct = true;
 332                                         break;
 333                                 case EQUALITY:
 334                                         FuncInst * to_be_compared;
 335                                         ModelAction * last_act;
 336
 337                                         to_be_compared = pred_expression->func_inst;
 338                                         last_act = inst_act_map->get(to_be_compared);
 339
 340                                         last_read = last_act->get_reads_from_value();
 341                                         next_read = next_act->get_reads_from_value();
 342                                         equality = (last_read == next_read);
 343                                         if (equality != pred_expression->value)
 344                                                 predicate_correct = false;
 345
 346                                         break;
 347                                 case NULLITY:
 348                                         next_read = next_act->get_reads_from_value();
 349                                         equality = ((void*)next_read == NULL);
 350                                         if (equality != pred_expression->value)
 351                                                 predicate_correct = false;
 352                                         break;
 353                                 default:
 354                                         predicate_correct = false;
 355                                         model_print("unkown predicate token\n");
 356                                         break;
 357                         }
 358                 }
 359
 360                 if (predicate_correct) {
 361                         *curr_pred = branch;
 362                         branch_found = true;
 363                         break;
 364                 }
 365         }
 366
 367         return branch_found;
 368 }
 369
 370 /* Infer predicate expressions, which are generated in FuncNode::generate_predicates */
 371 void FuncNode::infer_predicates(FuncInst * next_inst, ModelAction * next_act,
 372         HashTable<void *, ModelAction *, uintptr_t, 0> * loc_act_map,
 373         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 374 {
 375         void * loc = next_act->get_location();
 376
 377         if (next_inst->is_read()) {
 378                 /* read + rmw */
 379                 if ( loc_act_map->contains(loc) ) {
 380                         ModelAction * last_act = loc_act_map->get(loc);
 381                         FuncInst * last_inst = get_inst(last_act);
 382                         struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 383                         half_pred_expressions->push_back(expression);
 384                 } else if ( next_inst->is_single_location() ){
 385                         loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
 386
 387                         if (loc_may_equal != NULL) {
 388                                 loc_set_iter * loc_it = loc_may_equal->iterator();
 389                                 while (loc_it->hasNext()) {
 390                                         void * neighbor = loc_it->next();
 391                                         if (loc_act_map->contains(neighbor)) {
 392                                                 ModelAction * last_act = loc_act_map->get(neighbor);
 393                                                 FuncInst * last_inst = get_inst(last_act);
 394
 395                                                 struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 396                                                 half_pred_expressions->push_back(expression);
 397                                         }
 398                                 }
 399                         }
 400                 } else {
 401                         // next_inst is not single location
 402                         uint64_t read_val = next_act->get_reads_from_value();
 403
 404                         // only infer NULLITY predicate when it is actually NULL.
 405                         if ( (void*)read_val == NULL) {
 406                                 struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
 407                                 half_pred_expressions->push_back(expression);
 408                         }
 409                 }
 410         } else {
 411                 /* Pure writes */
 412                 // TODO: do anything here?
 413         }
 414 }
 415
 416 /* Able to generate complex predicates when there are multiple predciate expressions */
 417 void FuncNode::generate_predicates(Predicate ** curr_pred, FuncInst * next_inst,
 418         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 419 {
 420         if (half_pred_expressions->size() == 0) {
 421                 Predicate * new_pred = new Predicate(next_inst);
 422                 (*curr_pred)->add_child(new_pred);
 423                 new_pred->set_parent(*curr_pred);
 424
 425                 /* entry predicates and predicates containing pure write actions
 426                  * have no predicate expressions */
 427                 if ( (*curr_pred)->is_entry_predicate() )
 428                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 429                 else if (next_inst->is_write()) {
 430                         /* next_inst->is_write() <==> pure writes */
 431                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 432                 }
 433
 434                 return;
 435         }
 436
 437         SnapVector<Predicate *> predicates;
 438
 439         struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
 440         predicates.push_back(new Predicate(next_inst));
 441         predicates.push_back(new Predicate(next_inst));
 442
 443         predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 444         predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 445
 446         for (uint i = 1; i < half_pred_expressions->size(); i++) {
 447                 half_expr = (*half_pred_expressions)[i];
 448
 449                 uint old_size = predicates.size();
 450                 for (uint j = 0; j < old_size; j++) {
 451                         Predicate * pred = predicates[j];
 452                         Predicate * new_pred = new Predicate(next_inst);
 453                         new_pred->copy_predicate_expr(pred);
 454
 455                         pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 456                         new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 457
 458                         predicates.push_back(new_pred);
 459                 }
 460         }
 461
 462         for (uint i = 0; i < predicates.size(); i++) {
 463                 Predicate * pred= predicates[i];
 464                 (*curr_pred)->add_child(pred);
 465                 pred->set_parent(*curr_pred);
 466         }
 467 }
 468
 469 /* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
 470 bool FuncNode::amend_predicate_expr(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act)
 471 {
 472         // there should only be only child
 473         Predicate * unset_pred = (*curr_pred)->get_children()->back();
 474         uint64_t read_val = next_act->get_reads_from_value();
 475
 476         // only generate NULLITY predicate when it is actually NULL.
 477         if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
 478                 Predicate * new_pred = new Predicate(next_inst);
 479
 480                 (*curr_pred)->add_child(new_pred);
 481                 new_pred->set_parent(*curr_pred);
 482
 483                 unset_pred->add_predicate_expr(NULLITY, NULL, false);
 484                 new_pred->add_predicate_expr(NULLITY, NULL, true);
 485
 486                 return true;
 487         }
 488
 489         return false;
 490 }
 491
 492 void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 493 {
 494         loc_set_t * locations = val_loc_map->get(val);
 495
 496         if (locations == NULL) {
 497                 locations = new loc_set_t();
 498                 val_loc_map->put(val, locations);
 499         }
 500
 501         update_loc_may_equal_map(loc, locations);
 502         locations->add(loc);
 503         // values_may_read_from->add(val);
 504 }
 505
 506 void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
 507 {
 508         if (values == NULL)
 509                 return;
 510
 511         value_set_iter * it = values->iterator();
 512         while (it->hasNext()) {
 513                 uint64_t val = it->next();
 514                 add_to_val_loc_map(val, loc);
 515         }
 516 }
 517
 518 void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 519 {
 520         if ( old_locations->contains(new_loc) )
 521                 return;
 522
 523         loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
 524
 525         if (neighbors == NULL) {
 526                 neighbors = new loc_set_t();
 527                 loc_may_equal_map->put(new_loc, neighbors);
 528         }
 529
 530         loc_set_iter * loc_it = old_locations->iterator();
 531         while (loc_it->hasNext()) {
 532                 // new_loc: { old_locations, ... }
 533                 void * member = loc_it->next();
 534                 neighbors->add(member);
 535
 536                 // for each i in old_locations, i : { new_loc, ... }
 537                 loc_set_t * _neighbors = loc_may_equal_map->get(member);
 538                 if (_neighbors == NULL) {
 539                         _neighbors = new loc_set_t();
 540                         loc_may_equal_map->put(member, _neighbors);
 541                 }
 542                 _neighbors->add(new_loc);
 543         }
 544 }
 545
 546 /* Every time a thread enters a function, set its position to the predicate tree entry */
 547 void FuncNode::init_predicate_tree_position(thread_id_t tid)
 548 {
 549         int thread_id = id_to_int(tid);
 550         if (predicate_tree_position.size() <= (uint) thread_id)
 551                 predicate_tree_position.resize(thread_id + 1);
 552
 553         predicate_tree_position[thread_id] = predicate_tree_entry;
 554 }
 555
 556 void FuncNode::set_predicate_tree_position(thread_id_t tid, Predicate * pred)
 557 {
 558         int thread_id = id_to_int(tid);
 559         predicate_tree_position[thread_id] = pred;
 560 }
 561
 562 /* @return The position of a thread in a predicate tree */
 563 Predicate * FuncNode::get_predicate_tree_position(thread_id_t tid)
 564 {
 565         int thread_id = id_to_int(tid);
 566         return predicate_tree_position[thread_id];
 567 }
 568
 569 /* Make sure elements of thrd_inst_act_map are initialized properly when threads enter functions */
 570 void FuncNode::init_inst_act_map(thread_id_t tid)
 571 {
 572         int thread_id = id_to_int(tid);
 573         uint old_size = thrd_inst_act_map->size();
 574
 575         if (thrd_inst_act_map->size() <= (uint) thread_id) {
 576                 uint new_size = thread_id + 1;
 577                 thrd_inst_act_map->resize(new_size);
 578
 579                 for (uint i = old_size; i < new_size; i++)
 580                         (*thrd_inst_act_map)[i] = new inst_act_map_t(128);
 581         }
 582 }
 583
 584 /* Reset elements of thrd_inst_act_map when threads exit functions */
 585 void FuncNode::reset_inst_act_map(thread_id_t tid)
 586 {
 587         int thread_id = id_to_int(tid);
 588         inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
 589         map->reset();
 590 }
 591
 592 void FuncNode::update_inst_act_map(thread_id_t tid, ModelAction * read_act)
 593 {
 594         int thread_id = id_to_int(tid);
 595         inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
 596         FuncInst * read_inst = get_inst(read_act);
 597         map->put(read_inst, read_act);
 598 }
 599
 600 inst_act_map_t * FuncNode::get_inst_act_map(thread_id_t tid)
 601 {
 602         int thread_id = id_to_int(tid);
 603         return (*thrd_inst_act_map)[thread_id];
 604 }
 605
 606 void FuncNode::print_predicate_tree()
 607 {
 608         model_print("digraph function_%s {\n", func_name);
 609         predicate_tree_entry->print_pred_subtree();
 610         model_print("}\n");     // end of graph
 611 }
 612
 613 void FuncNode::print_val_loc_map()
 614 {
 615 /*
 616         value_set_iter * val_it = values_may_read_from->iterator();
 617         while (val_it->hasNext()) {
 618                 uint64_t value = val_it->next();
 619                 model_print("val %llx: ", value);
 620
 621                 loc_set_t * locations = val_loc_map->get(value);
 622                 loc_set_iter * loc_it = locations->iterator();
 623                 while (loc_it->hasNext()) {
 624                         void * location = loc_it->next();
 625                         model_print("%p ", location);
 626                 }
 627                 model_print("\n");
 628         }
 629 */
 630 }