scanalysis.cc

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