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