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 {
  13         predicate_tree_entry = new Predicate(NULL, true);
  14         predicate_tree_entry->add_predicate_expr(NOPREDICATE, NULL, true);
  15
  16         // memory will be 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         values_may_read_from = new value_set_t();
  21 }
  22
  23 /* Reallocate some snapshotted memories when new executions start */
  24 void FuncNode::set_new_exec_flag()
  25 {
  26 //      for (uint i = 0; i < thrd_read_map.size(); i++)
  27 //              thrd_read_map[i] = new read_map_t();
  28
  29         for (mllnode<FuncInst *> * it = inst_list.begin(); it != NULL; it = it->getNext()) {
  30                 FuncInst * inst = it->getVal();
  31                 inst->reset_location();
  32         }
  33
  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         values_may_read_from = new value_set_t();
  38 }
  39
  40 /* Check whether FuncInst with the same type, position, and location
  41  * as act has been added to func_inst_map or not. If not, add it.
  42  *
  43  * Note: currently, actions with the same position are filtered out by process_action,
  44  * so the collision list of FuncInst is not used. May remove it later.
  45  */
  46 void FuncNode::add_inst(ModelAction *act)
  47 {
  48         ASSERT(act);
  49         const char * position = act->get_position();
  50
  51         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  52          * actions are not tagged with their source line numbers
  53          */
  54         if (position == NULL)
  55                 return;
  56
  57         if ( func_inst_map.contains(position) ) {
  58                 FuncInst * inst = func_inst_map.get(position);
  59
  60                 ASSERT(inst->get_type() == act->get_type());
  61
  62                 // locations are set to NULL when new executions start
  63                 if (inst->get_location() == NULL)
  64                         inst->set_location(act->get_location());
  65
  66                 if (inst->get_location() != act->get_location())
  67                         inst->not_single_location();
  68
  69                 return;
  70         }
  71
  72         FuncInst * func_inst = new FuncInst(act, this);
  73
  74         func_inst_map.put(position, func_inst);
  75         inst_list.push_back(func_inst);
  76 }
  77
  78 /* Get the FuncInst with the same type, position, and location
  79  * as act
  80  *
  81  * @return FuncInst with the same type, position, and location as act */
  82 FuncInst * FuncNode::get_inst(ModelAction *act)
  83 {
  84         ASSERT(act);
  85         const char * position = act->get_position();
  86
  87         /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
  88          * actions are not tagged with their source line numbers
  89          */
  90         if (position == NULL)
  91                 return NULL;
  92
  93         FuncInst * inst = func_inst_map.get(position);
  94         if (inst == NULL)
  95                 return NULL;
  96
  97         action_type inst_type = inst->get_type();
  98         action_type act_type = act->get_type();
  99
 100         // else if branch: an RMWRCAS action is converted to a RMW or READ action
 101         if (inst_type == act_type)
 102                 return inst;
 103         else if (inst_type == ATOMIC_RMWRCAS &&
 104                         (act_type == ATOMIC_RMW || act_type == ATOMIC_READ))
 105                 return inst;
 106
 107         return NULL;
 108 }
 109
 110
 111 void FuncNode::add_entry_inst(FuncInst * inst)
 112 {
 113         if (inst == NULL)
 114                 return;
 115
 116         mllnode<FuncInst *> * it;
 117         for (it = entry_insts.begin(); it != NULL; it = it->getNext()) {
 118                 if (inst == it->getVal())
 119                         return;
 120         }
 121
 122         entry_insts.push_back(inst);
 123 }
 124
 125 /**
 126  * @brief Convert ModelAdtion list to FuncInst list
 127  * @param act_list A list of ModelActions
 128  */
 129 void FuncNode::update_tree(action_list_t * act_list)
 130 {
 131         if (act_list == NULL || act_list->size() == 0)
 132                 return;
 133
 134         HashTable<void *, value_set_t *, uintptr_t, 4> * write_history = history->getWriteHistory();
 135
 136         /* build inst_list from act_list for later processing */
 137         func_inst_list_t inst_list;
 138         action_list_t read_act_list;
 139
 140         for (sllnode<ModelAction *> * it = act_list->begin(); it != NULL; it = it->getNext()) {
 141                 ModelAction * act = it->getVal();
 142                 FuncInst * func_inst = get_inst(act);
 143
 144                 if (func_inst == NULL)
 145                         continue;
 146
 147                 inst_list.push_back(func_inst);
 148
 149                 if (func_inst->is_read()) {
 150                         read_act_list.push_back(act);
 151
 152                         /* the first time an action reads from some location, import all the values that have
 153                          * been written to this location from ModelHistory and notify ModelHistory that this
 154                          * FuncNode may read from this location.
 155                          */
 156                         void * loc = act->get_location();
 157                         if (!read_locations->contains(loc)) {
 158                                 read_locations->add(loc);
 159                                 value_set_t * write_values = write_history->get(loc);
 160                                 add_to_val_loc_map(write_values, loc);
 161                                 history->add_to_loc_func_nodes_map(loc, this);
 162                         }
 163                 }
 164         }
 165
 166         model_print("function %s\n", func_name);
 167 //      print_val_loc_map();
 168
 169         update_inst_tree(&inst_list);
 170         update_predicate_tree(&read_act_list);
 171
 172         print_predicate_tree();
 173 }
 174
 175 /**
 176  * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
 177  * @param inst_list A list of FuncInsts
 178  */
 179 void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
 180 {
 181         if (inst_list == NULL)
 182                 return;
 183         else if (inst_list->size() == 0)
 184                 return;
 185
 186         /* start linking */
 187         sllnode<FuncInst *>* it = inst_list->begin();
 188         sllnode<FuncInst *>* prev;
 189
 190         /* add the first instruction to the list of entry insts */
 191         FuncInst * entry_inst = it->getVal();
 192         add_entry_inst(entry_inst);
 193
 194         it = it->getNext();
 195         while (it != NULL) {
 196                 prev = it->getPrev();
 197
 198                 FuncInst * prev_inst = prev->getVal();
 199                 FuncInst * curr_inst = it->getVal();
 200
 201                 prev_inst->add_succ(curr_inst);
 202                 curr_inst->add_pred(prev_inst);
 203
 204                 it = it->getNext();
 205         }
 206 }
 207
 208 /* @param tid thread id
 209  * Store the values read by atomic read actions into thrd_read_map */
 210 void FuncNode::store_read(ModelAction * act, uint32_t tid)
 211 {
 212 /*
 213         ASSERT(act);
 214
 215         void * location = act->get_location();
 216         uint64_t read_from_val = act->get_reads_from_value();
 217
 218         // resize and initialize
 219         uint32_t old_size = thrd_read_map.size();
 220         if (old_size <= tid) {
 221                 thrd_read_map.resize(tid + 1);
 222                 for (uint32_t i = old_size; i < tid + 1;i++)
 223                         thrd_read_map[i] = new read_map_t();
 224         }
 225
 226         read_map_t * read_map = thrd_read_map[tid];
 227         read_map->put(location, read_from_val);
 228 */
 229 }
 230
 231 uint64_t FuncNode::query_last_read(void * location, uint32_t tid)
 232 {
 233 /*
 234         if (thrd_read_map.size() <= tid)
 235                 return VALUE_NONE;
 236
 237         read_map_t * read_map = thrd_read_map[tid];
 238
 239         // last read value not found
 240         if ( !read_map->contains(location) )
 241                 return VALUE_NONE;
 242
 243         uint64_t read_val = read_map->get(location);
 244         return read_val;
 245 */
 246 }
 247
 248 /* @param tid thread id
 249  * Reset read map for a thread. This function shall only be called
 250  * when a thread exits a function
 251  */
 252 void FuncNode::clear_read_map(uint32_t tid)
 253 {
 254 /*
 255         if (thrd_read_map.size() <= tid)
 256                 return;
 257
 258         thrd_read_map[tid]->reset();
 259 */
 260 }
 261
 262 void FuncNode::update_predicate_tree(action_list_t * act_list)
 263 {
 264         if (act_list == NULL || act_list->size() == 0)
 265                 return;
 266
 267         /* map a FuncInst to the its predicate */
 268         HashTable<FuncInst *, Predicate *, uintptr_t, 0> inst_pred_map(128);
 269
 270         // number FuncInsts to detect loops
 271         HashTable<FuncInst *, uint32_t, uintptr_t, 0> inst_id_map(128);
 272         uint32_t inst_counter = 0;
 273
 274         HashTable<void *, ModelAction *, uintptr_t, 0> loc_act_map(128);
 275         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> inst_act_map(128);
 276
 277         sllnode<ModelAction *> *it = act_list->begin();
 278         Predicate * curr_pred = predicate_tree_entry;
 279         while (it != NULL) {
 280                 ModelAction * next_act = it->getVal();
 281                 FuncInst * next_inst = get_inst(next_act);
 282
 283                 SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
 284                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, &unset_predicates);
 285
 286                 // no predicate expressions
 287                 if (!branch_found && unset_predicates.size() != 0) {
 288                         ASSERT(unset_predicates.size() == 1);
 289                         Predicate * one_branch = unset_predicates[0];
 290
 291                         bool amended = amend_predicate_expr(&curr_pred, next_inst, next_act);
 292                         if (amended)
 293                                 continue;
 294                         else {
 295                                 curr_pred = one_branch;
 296                                 branch_found = true;
 297                         }
 298                 }
 299
 300                 // detect loops
 301                 if (!branch_found && inst_id_map.contains(next_inst)) {
 302                         FuncInst * curr_inst = curr_pred->get_func_inst();
 303                         uint32_t curr_id = inst_id_map.get(curr_inst);
 304                         uint32_t next_id = inst_id_map.get(next_inst);
 305
 306                         if (curr_id >= next_id) {
 307                                 Predicate * old_pred = inst_pred_map.get(next_inst);
 308                                 Predicate * back_pred = old_pred->get_parent();
 309
 310                                 curr_pred->add_backedge(back_pred);
 311                                 curr_pred = back_pred;
 312
 313                                 continue;
 314                         }
 315                 }
 316
 317                 // generate new branches
 318                 if (!branch_found) {
 319                         SnapVector<struct half_pred_expr *> half_pred_expressions;
 320                         void * loc = next_act->get_location();
 321
 322                         if ( loc_act_map.contains(loc) ) {
 323                                 ModelAction * last_act = loc_act_map.get(loc);
 324                                 FuncInst * last_inst = get_inst(last_act);
 325                                 struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 326                                 half_pred_expressions.push_back(expression);
 327                         } else if ( next_inst->is_single_location() ){
 328                                 loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
 329
 330                                 if (loc_may_equal != NULL) {
 331                                         loc_set_iter * loc_it = loc_may_equal->iterator();
 332                                         while (loc_it->hasNext()) {
 333                                                 void * neighbor = loc_it->next();
 334                                                 if (loc_act_map.contains(neighbor)) {
 335                                                         ModelAction * last_act = loc_act_map.get(neighbor);
 336                                                         FuncInst * last_inst = get_inst(last_act);
 337
 338                                                         struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
 339                                                         half_pred_expressions.push_back(expression);
 340                                                 }
 341                                         }
 342                                 }
 343                         } else {
 344                                 // next_inst is not single location
 345                                 uint64_t read_val = next_act->get_reads_from_value();
 346
 347                                 // only generate NULLITY predicate when it is actually NULL.
 348                                 if ( (void*)read_val == NULL) {
 349                                         struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
 350                                         half_pred_expressions.push_back(expression);
 351                                 }
 352                         }
 353
 354                         if (half_pred_expressions.size() == 0) {
 355                                 // no predicate needs to be generated
 356                                 Predicate * new_pred = new Predicate(next_inst);
 357                                 curr_pred->add_child(new_pred);
 358                                 new_pred->set_parent(curr_pred);
 359
 360                                 if (curr_pred->is_entry_predicate())
 361                                         new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
 362
 363                                 curr_pred = new_pred;
 364                         } else {
 365                                 generate_predicate(&curr_pred, next_inst, &half_pred_expressions);
 366                                 bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &inst_act_map, NULL);
 367                                 ASSERT(branch_found);
 368                         }
 369                 }
 370
 371                 inst_pred_map.put(next_inst, curr_pred);
 372                 if (!inst_id_map.contains(next_inst))
 373                         inst_id_map.put(next_inst, inst_counter++);
 374
 375                 loc_act_map.put(next_act->get_location(), next_act);
 376                 inst_act_map.put(next_inst, next_act);
 377                 it = it->getNext();
 378         }
 379 }
 380
 381 /* Given curr_pred and next_inst, find the branch following curr_pred that
 382  * contains next_inst and the correct predicate.
 383  * @return true if branch found, false otherwise.
 384  */
 385 bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act,
 386         HashTable<FuncInst *, ModelAction *, uintptr_t, 0> * inst_act_map,
 387         SnapVector<Predicate *> * unset_predicates)
 388 {
 389         /* check if a branch with func_inst and corresponding predicate exists */
 390         bool branch_found = false;
 391         ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
 392         for (uint i = 0; i < branches->size(); i++) {
 393                 Predicate * branch = (*branches)[i];
 394                 if (branch->get_func_inst() != next_inst)
 395                         continue;
 396
 397                 /* check against predicate expressions */
 398                 bool predicate_correct = true;
 399                 PredExprSet * pred_expressions = branch->get_pred_expressions();
 400                 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
 401
 402                 if (pred_expressions->getSize() == 0) {
 403                         predicate_correct = false;
 404                         unset_predicates->push_back(branch);
 405                 }
 406
 407                 while (pred_expr_it->hasNext()) {
 408                         pred_expr * pred_expression = pred_expr_it->next();
 409                         uint64_t last_read, next_read;
 410                         bool equality;
 411
 412                         switch(pred_expression->token) {
 413                                 case NOPREDICATE:
 414                                         predicate_correct = true;
 415                                         break;
 416                                 case EQUALITY:
 417                                         FuncInst * to_be_compared;
 418                                         ModelAction * last_act;
 419
 420                                         to_be_compared = pred_expression->func_inst;
 421                                         last_act = inst_act_map->get(to_be_compared);
 422
 423                                         last_read = last_act->get_reads_from_value();
 424                                         next_read = next_act->get_reads_from_value();
 425                                         equality = (last_read == next_read);
 426                                         if (equality != pred_expression->value)
 427                                                 predicate_correct = false;
 428
 429                                         break;
 430                                 case NULLITY:
 431                                         next_read = next_act->get_reads_from_value();
 432                                         equality = ((void*)next_read == NULL);
 433                                         if (equality != pred_expression->value)
 434                                                 predicate_correct = false;
 435                                         break;
 436                                 default:
 437                                         predicate_correct = false;
 438                                         model_print("unkown predicate token\n");
 439                                         break;
 440                         }
 441                 }
 442
 443                 if (predicate_correct) {
 444                         *curr_pred = branch;
 445                         branch_found = true;
 446                         break;
 447                 }
 448         }
 449
 450         return branch_found;
 451 }
 452
 453 /* Able to generate complex predicates when there are multiple predciate expressions */
 454 void FuncNode::generate_predicate(Predicate ** curr_pred, FuncInst * next_inst,
 455         SnapVector<struct half_pred_expr *> * half_pred_expressions)
 456 {
 457         ASSERT(half_pred_expressions->size() != 0);
 458         SnapVector<Predicate *> predicates;
 459
 460         struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
 461         predicates.push_back(new Predicate(next_inst));
 462         predicates.push_back(new Predicate(next_inst));
 463
 464         predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 465         predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 466
 467         for (uint i = 1; i < half_pred_expressions->size(); i++) {
 468                 half_expr = (*half_pred_expressions)[i];
 469
 470                 uint old_size = predicates.size();
 471                 for (uint j = 0; j < old_size; j++) {
 472                         Predicate * pred = predicates[j];
 473                         Predicate * new_pred = new Predicate(next_inst);
 474                         new_pred->copy_predicate_expr(pred);
 475
 476                         pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
 477                         new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
 478
 479                         predicates.push_back(new_pred);
 480                 }
 481         }
 482
 483         for (uint i = 0; i < predicates.size(); i++) {
 484                 Predicate * pred= predicates[i];
 485                 (*curr_pred)->add_child(pred);
 486                 pred->set_parent(*curr_pred);
 487         }
 488 }
 489
 490 /* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
 491 bool FuncNode::amend_predicate_expr(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act)
 492 {
 493         // there should only be only child
 494         Predicate * unset_pred = (*curr_pred)->get_children()->back();
 495         uint64_t read_val = next_act->get_reads_from_value();
 496
 497         // only generate NULLITY predicate when it is actually NULL.
 498         if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
 499                 Predicate * new_pred = new Predicate(next_inst);
 500
 501                 (*curr_pred)->add_child(new_pred);
 502                 new_pred->set_parent(*curr_pred);
 503
 504                 unset_pred->add_predicate_expr(NULLITY, NULL, false);
 505                 new_pred->add_predicate_expr(NULLITY, NULL, true);
 506
 507                 return true;
 508         }
 509
 510         return false;
 511 }
 512
 513 void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 514 {
 515         loc_set_t * locations = val_loc_map->get(val);
 516
 517         if (locations == NULL) {
 518                 locations = new loc_set_t();
 519                 val_loc_map->put(val, locations);
 520         }
 521
 522         update_loc_may_equal_map(loc, locations);
 523         locations->add(loc);
 524         values_may_read_from->add(val);
 525 }
 526
 527 void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
 528 {
 529         value_set_iter * it = values->iterator();
 530         while (it->hasNext()) {
 531                 uint64_t val = it->next();
 532                 add_to_val_loc_map(val, loc);
 533         }
 534 }
 535
 536 void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 537 {
 538         loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
 539
 540         if (neighbors == NULL) {
 541                 neighbors = new loc_set_t();
 542                 loc_may_equal_map->put(new_loc, neighbors);
 543         }
 544
 545         loc_set_iter * loc_it = old_locations->iterator();
 546         while (loc_it->hasNext()) {
 547                 // new_loc: { old_locations, ... }
 548                 void * member = loc_it->next();
 549                 neighbors->add(member);
 550
 551                 // for each i in old_locations, i : { new_loc, ... }
 552                 loc_set_t * _neighbors = loc_may_equal_map->get(member);
 553                 if (_neighbors == NULL) {
 554                         _neighbors = new loc_set_t();
 555                         loc_may_equal_map->put(member, _neighbors);
 556                 }
 557                 _neighbors->add(new_loc);
 558         }
 559 }
 560
 561 void FuncNode::print_predicate_tree()
 562 {
 563         model_print("digraph function_%s {\n", func_name);
 564         predicate_tree_entry->print_pred_subtree();
 565         model_print("}\n");     // end of graph
 566 }
 567
 568 void FuncNode::print_val_loc_map()
 569 {
 570         value_set_iter * val_it = values_may_read_from->iterator();
 571         while (val_it->hasNext()) {
 572                 uint64_t value = val_it->next();
 573                 model_print("val %llx: ", value);
 574
 575                 loc_set_t * locations = val_loc_map->get(value);
 576                 loc_set_iter * loc_it = locations->iterator();
 577                 while (loc_it->hasNext()) {
 578                         void * location = loc_it->next();
 579                         model_print("%p ", location);
 580                 }
 581                 model_print("\n");
 582         }
 583 }
 584
 585 /* @param tid thread id
 586  * Print the values read by the last read actions for each memory location
 587  */
 588 /*
 589 void FuncNode::print_last_read(uint32_t tid)
 590 {
 591         ASSERT(thrd_read_map.size() > tid);
 592         read_map_t * read_map = thrd_read_map[tid];
 593
 594         mllnode<void *> * it;
 595         for (it = read_locations.begin();it != NULL;it=it->getNext()) {
 596                 if ( !read_map->contains(it->getVal()) )
 597                         break;
 598
 599                 uint64_t read_val = read_map->get(it->getVal());
 600                 model_print("last read of thread %d at %p: 0x%x\n", tid, it->getVal(), read_val);
 601         }
 602 }
 603 */