scanalysis.cc

   1 #include "scanalysis.h"
   2 #include "action.h"
   3 #include "threads-model.h"
   4 #include "clockvector.h"
   5 #include "execution.h"
   6 #include <sys/time.h>
   7
   8
   9 SCAnalysis::SCAnalysis() :
  10         cvmap(),
  11         cyclic(false),
  12         badrfset(),
  13         lastwrmap(),
  14         threadlists(1),
  15         execution(NULL),
  16         print_always(false),
  17         print_buggy(true),
  18         print_nonsc(false),
  19         time(false),
  20         stats((struct sc_statistics *)model_calloc(1, sizeof(struct sc_statistics)))
  21 {
  22 }
  23
  24 SCAnalysis::~SCAnalysis() {
  25         delete(stats);
  26 }
  27
  28 void SCAnalysis::setExecution(ModelExecution * execution) {
  29         this->execution=execution;
  30 }
  31
  32 const char * SCAnalysis::name() {
  33         const char * name = "SC";
  34         return name;
  35 }
  36
  37 void SCAnalysis::finish() {
  38         if (time)
  39                 model_print("Elapsed time in usec %llu\n", stats->elapsedtime);
  40         model_print("SC count: %u\n", stats->sccount);
  41         model_print("Non-SC count: %u\n", stats->nonsccount);
  42 }
  43
  44 bool SCAnalysis::option(char * opt) {
  45         if (strcmp(opt, "verbose")==0) {
  46                 print_always=true;
  47                 return false;
  48         } else if (strcmp(opt, "buggy")==0) {
  49                 return false;
  50         } else if (strcmp(opt, "quiet")==0) {
  51                 print_buggy=false;
  52                 return false;
  53         } else if (strcmp(opt, "nonsc")==0) {
  54                 print_nonsc=true;
  55                 return false;
  56         } else if (strcmp(opt, "time")==0) {
  57                 time=true;
  58                 return false;
  59         } else if (strcmp(opt, "help") != 0) {
  60                 model_print("Unrecognized option: %s\n", opt);
  61         }
  62
  63         model_print("SC Analysis options\n");
  64         model_print("verbose -- print all feasible executions\n");
  65         model_print("buggy -- print only buggy executions (default)\n");
  66         model_print("nonsc -- print non-sc execution\n");
  67         model_print("quiet -- print nothing\n");
  68         model_print("time -- time execution of scanalysis\n");
  69         model_print("\n");
  70
  71         return true;
  72 }
  73
  74 void SCAnalysis::print_list(action_list_t *list) {
  75         model_print("---------------------------------------------------------------------\n");
  76         if (cyclic)
  77                 model_print("Not SC\n");
  78         unsigned int hash = 0;
  79
  80         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
  81                 const ModelAction *act = *it;
  82                 if (act->get_seq_number() > 0) {
  83                         if (badrfset.contains(act))
  84                                 model_print("BRF ");
  85                         act->print();
  86                         if (badrfset.contains(act)) {
  87                                 model_print("Desired Rf: %u \n", badrfset.get(act)->get_seq_number());
  88                         }
  89                 }
  90                 hash = hash ^ (hash << 3) ^ ((*it)->hash());
  91         }
  92         model_print("HASH %u\n", hash);
  93         model_print("---------------------------------------------------------------------\n");
  94 }
  95
  96 void SCAnalysis::analyze(action_list_t *actions) {
  97
  98         struct timeval start;
  99         struct timeval finish;
 100         if (time)
 101                 gettimeofday(&start, NULL);
 102         action_list_t *list = generateSC(actions);
 103         check_rf(list);
 104         if (print_always || (print_buggy && execution->have_bug_reports())|| (print_nonsc && cyclic))
 105                 print_list(list);
 106         if (time) {
 107                 gettimeofday(&finish, NULL);
 108                 stats->elapsedtime+=((finish.tv_sec*1000000+finish.tv_usec)-(start.tv_sec*1000000+start.tv_usec));
 109         }
 110         update_stats();
 111 }
 112
 113 void SCAnalysis::update_stats() {
 114         if (cyclic) {
 115                 stats->nonsccount++;
 116         } else {
 117                 stats->sccount++;
 118         }
 119 }
 120
 121 void SCAnalysis::check_rf(action_list_t *list) {
 122         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 123                 const ModelAction *act = *it;
 124                 if (act->is_read()) {
 125                         if (act->get_reads_from() != lastwrmap.get(act->get_location()))
 126                                 badrfset.put(act, lastwrmap.get(act->get_location()));
 127                 }
 128                 if (act->is_write())
 129                         lastwrmap.put(act->get_location(), act);
 130         }
 131 }
 132
 133 bool SCAnalysis::merge(ClockVector *cv, const ModelAction *act, const ModelAction *act2) {
 134         ClockVector *cv2 = cvmap.get(act2);
 135         if (cv2 == NULL)
 136                 return true;
 137         if (cv2->getClock(act->get_tid()) >= act->get_seq_number() && act->get_seq_number() != 0) {
 138                 cyclic = true;
 139                 //refuse to introduce cycles into clock vectors
 140                 return false;
 141         }
 142
 143         return cv->merge(cv2);
 144 }
 145
 146 int SCAnalysis::getNextActions(ModelAction ** array) {
 147         int count=0;
 148
 149         for (int t = 0; t <= maxthreads; t++) {
 150                 action_list_t *tlt = &threadlists[t];
 151                 if (tlt->empty())
 152                         continue;
 153                 ModelAction *act = tlt->front();
 154                 ClockVector *cv = cvmap.get(act);
 155
 156                 /* Find the earliest in SC ordering */
 157                 for (int i = 0; i <= maxthreads; i++) {
 158                         if ( i == t )
 159                                 continue;
 160                         action_list_t *threadlist = &threadlists[i];
 161                         if (threadlist->empty())
 162                                 continue;
 163                         ModelAction *first = threadlist->front();
 164                         if (cv->synchronized_since(first)) {
 165                                 act = NULL;
 166                                 break;
 167                         }
 168                 }
 169                 if (act != NULL) {
 170                         array[count++]=act;
 171                 }
 172         }
 173         if (count != 0)
 174                 return count;
 175         for (int t = 0; t <= maxthreads; t++) {
 176                 action_list_t *tlt = &threadlists[t];
 177                 if (tlt->empty())
 178                         continue;
 179                 ModelAction *act = tlt->front();
 180                 ClockVector *cv = act->get_cv();
 181
 182                 /* Find the earliest in SC ordering */
 183                 for (int i = 0; i <= maxthreads; i++) {
 184                         if ( i == t )
 185                                 continue;
 186                         action_list_t *threadlist = &threadlists[i];
 187                         if (threadlist->empty())
 188                                 continue;
 189                         ModelAction *first = threadlist->front();
 190                         if (cv->synchronized_since(first)) {
 191                                 act = NULL;
 192                                 break;
 193                         }
 194                 }
 195                 if (act != NULL) {
 196                         array[count++]=act;
 197                 }
 198         }
 199
 200         ASSERT(count==0 || cyclic);
 201
 202         return count;
 203 }
 204
 205 ModelAction * SCAnalysis::pruneArray(ModelAction **array,int count) {
 206         /* No choice */
 207         if (count == 1)
 208                 return array[0];
 209
 210         /* Choose first non-write action */
 211         ModelAction *nonwrite=NULL;
 212         for(int i=0;i<count;i++) {
 213                 if (!array[i]->is_write())
 214                         if (nonwrite==NULL || nonwrite->get_seq_number() > array[i]->get_seq_number())
 215                                 nonwrite = array[i];
 216         }
 217         if (nonwrite != NULL)
 218                 return nonwrite;
 219
 220         /* Look for non-conflicting action */
 221         ModelAction *nonconflict=NULL;
 222         for(int a=0;a<count;a++) {
 223                 ModelAction *act=array[a];
 224                 for (int i = 0; i <= maxthreads && act != NULL; i++) {
 225                         thread_id_t tid = int_to_id(i);
 226                         if (tid == act->get_tid())
 227                                 continue;
 228
 229                         action_list_t *list = &threadlists[id_to_int(tid)];
 230                         for (action_list_t::iterator rit = list->begin(); rit != list->end(); rit++) {
 231                                 ModelAction *write = *rit;
 232                                 if (!write->is_write())
 233                                         continue;
 234                                 ClockVector *writecv = cvmap.get(write);
 235                                 if (writecv->synchronized_since(act))
 236                                         break;
 237                                 if (write->get_location() == act->get_location()) {
 238                                         //write is sc after act
 239                                         act = NULL;
 240                                         break;
 241                                 }
 242                         }
 243                 }
 244                 if (act != NULL) {
 245                         if (nonconflict == NULL || nonconflict->get_seq_number() > act->get_seq_number())
 246                                 nonconflict=act;
 247                 }
 248         }
 249         return nonconflict;
 250 }
 251
 252 action_list_t * SCAnalysis::generateSC(action_list_t *list) {
 253         int numactions=buildVectors(list);
 254         computeCV(list);
 255
 256         action_list_t *sclist = new action_list_t();
 257         ModelAction **array = (ModelAction **)model_calloc(1, (maxthreads + 1) * sizeof(ModelAction *));
 258         int * choices = (int *) model_calloc(1, sizeof(int)*numactions);
 259         int endchoice = 0;
 260         int currchoice = 0;
 261         int lastchoice = -1;
 262         while (true) {
 263                 int numActions = getNextActions(array);
 264                 if (numActions == 0)
 265                         break;
 266                 ModelAction * act=pruneArray(array, numActions);
 267                 if (act == NULL) {
 268                         if (currchoice < endchoice) {
 269                                 act = array[choices[currchoice]];
 270                                 //check whether there is still another option
 271                                 if ((choices[currchoice]+1)<numActions)
 272                                         lastchoice=currchoice;
 273                                 currchoice++;
 274                         } else {
 275                                 act = array[0];
 276                                 choices[currchoice]=0;
 277                                 if (numActions>1)
 278                                         lastchoice=currchoice;
 279                                 currchoice++;
 280                         }
 281                 }
 282                 thread_id_t tid = act->get_tid();
 283                 //remove action
 284                 threadlists[id_to_int(tid)].pop_front();
 285                 //add ordering constraints from this choice
 286                 if (updateConstraints(act)) {
 287                         //propagate changes if we have them
 288                         bool prevc=cyclic;
 289                         computeCV(list);
 290                         if (!prevc && cyclic) {
 291                                 model_print("ROLLBACK in SC\n");
 292                                 //check whether we have another choice
 293                                 if (lastchoice != -1) {
 294                                         //have to reset everything
 295                                         choices[lastchoice]++;
 296                                         endchoice=lastchoice+1;
 297                                         currchoice=0;
 298                                         lastchoice=-1;
 299                                         reset(list);
 300                                         buildVectors(list);
 301                                         computeCV(list);
 302                                         sclist->clear();
 303                                         continue;
 304                                 }
 305                         }
 306                 }
 307                 //add action to end
 308                 sclist->push_back(act);
 309         }
 310         model_free(array);
 311         return sclist;
 312 }
 313
 314 int SCAnalysis::buildVectors(action_list_t *list) {
 315         maxthreads = 0;
 316         int numactions = 0;
 317         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 318                 ModelAction *act = *it;
 319                 numactions++;
 320                 int threadid = id_to_int(act->get_tid());
 321                 if (threadid > maxthreads) {
 322                         threadlists.resize(threadid + 1);
 323                         maxthreads = threadid;
 324                 }
 325                 threadlists[threadid].push_back(act);
 326         }
 327         return numactions;
 328 }
 329
 330 void SCAnalysis::reset(action_list_t *list) {
 331         for (int t = 0; t <= maxthreads; t++) {
 332                 action_list_t *tlt = &threadlists[t];
 333                 tlt->clear();
 334         }
 335         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 336                 ModelAction *act = *it;
 337                 delete cvmap.get(act);
 338                 cvmap.put(act, NULL);
 339         }
 340
 341         cyclic=false;
 342 }
 343
 344 bool SCAnalysis::updateConstraints(ModelAction *act) {
 345         bool changed = false;
 346         for (int i = 0; i <= maxthreads; i++) {
 347                 thread_id_t tid = int_to_id(i);
 348                 if (tid == act->get_tid())
 349                         continue;
 350
 351                 action_list_t *list = &threadlists[id_to_int(tid)];
 352                 for (action_list_t::iterator rit = list->begin(); rit != list->end(); rit++) {
 353                         ModelAction *write = *rit;
 354                         if (!write->is_write())
 355                                 continue;
 356                         ClockVector *writecv = cvmap.get(write);
 357                         if (writecv->synchronized_since(act))
 358                                 break;
 359                         if (write->get_location() == act->get_location()) {
 360                                 //write is sc after act
 361                                 merge(writecv, write, act);
 362                                 changed = true;
 363                                 break;
 364                         }
 365                 }
 366         }
 367         return changed;
 368 }
 369
 370 bool SCAnalysis::processRead(ModelAction *read, ClockVector *cv) {
 371         bool changed = false;
 372
 373         /* Merge in the clock vector from the write */
 374         const ModelAction *write = read->get_reads_from();
 375         ClockVector *writecv = cvmap.get(write);
 376         changed |= merge(cv, read, write) && (*read < *write);
 377
 378         for (int i = 0; i <= maxthreads; i++) {
 379                 thread_id_t tid = int_to_id(i);
 380                 if (tid == read->get_tid())
 381                         continue;
 382                 if (tid == write->get_tid())
 383                         continue;
 384                 action_list_t *list = execution->get_actions_on_obj(read->get_location(), tid);
 385                 if (list == NULL)
 386                         continue;
 387                 for (action_list_t::reverse_iterator rit = list->rbegin(); rit != list->rend(); rit++) {
 388                         ModelAction *write2 = *rit;
 389                         if (!write2->is_write())
 390                                 continue;
 391
 392                         ClockVector *write2cv = cvmap.get(write2);
 393                         if (write2cv == NULL)
 394                                 continue;
 395
 396                         /* write -sc-> write2 &&
 397                                  write -rf-> R =>
 398                                  R -sc-> write2 */
 399                         if (write2cv->synchronized_since(write)) {
 400                                 changed |= merge(write2cv, write2, read);
 401                         }
 402
 403                         //looking for earliest write2 in iteration to satisfy this
 404                         /* write2 -sc-> R &&
 405                                  write -rf-> R =>
 406                                  write2 -sc-> write */
 407                         if (cv->synchronized_since(write2)) {
 408                                 changed |= writecv == NULL || merge(writecv, write, write2);
 409                                 break;
 410                         }
 411                 }
 412         }
 413         return changed;
 414 }
 415
 416 void SCAnalysis::computeCV(action_list_t *list) {
 417         bool changed = true;
 418         bool firsttime = true;
 419         ModelAction **last_act = (ModelAction **)model_calloc(1, (maxthreads + 1) * sizeof(ModelAction *));
 420         while (changed) {
 421                 changed = changed&firsttime;
 422                 firsttime = false;
 423
 424                 for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 425                         ModelAction *act = *it;
 426                         ModelAction *lastact = last_act[id_to_int(act->get_tid())];
 427                         if (act->is_thread_start())
 428                                 lastact = execution->get_thread(act)->get_creation();
 429                         last_act[id_to_int(act->get_tid())] = act;
 430                         ClockVector *cv = cvmap.get(act);
 431                         if (cv == NULL) {
 432                                 cv = new ClockVector(NULL, act);
 433                                 cvmap.put(act, cv);
 434                         }
 435                         if (lastact != NULL) {
 436                                 merge(cv, act, lastact);
 437                         }
 438                         if (act->is_thread_join()) {
 439                                 Thread *joinedthr = act->get_thread_operand();
 440                                 ModelAction *finish = execution->get_last_action(joinedthr->get_id());
 441                                 changed |= merge(cv, act, finish);
 442                         }
 443                         if (act->is_read()) {
 444                                 changed |= processRead(act, cv);
 445                         }
 446                 }
 447                 /* Reset the last action array */
 448                 if (changed) {
 449                         bzero(last_act, (maxthreads + 1) * sizeof(ModelAction *));
 450                 }
 451         }
 452         model_free(last_act);
 453 }