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                         cvmap.get(act)->print();
  33                         if (badrfset.contains(act)) {
  34                                 model_print("DESIRED %u \n",badrfset.get(act)->get_seq_number());
  35                         }
  36                 }
  37                 hash = hash ^ (hash << 3) ^ ((*it)->hash());
  38         }
  39         model_print("HASH %u\n", hash);
  40         model_print("---------------------------------------------------------------------\n");
  41 }
  42
  43 void SCAnalysis::analyze(action_list_t *actions) {
  44         buildVectors(actions);
  45         computeCV(actions);
  46         action_list_t *list = generateSC(actions);
  47         check_rf(list);
  48         print_list(list);
  49 }
  50
  51 void SCAnalysis::check_rf(action_list_t *list) {
  52         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
  53                 const ModelAction *act = *it;
  54                 if (act->is_read()) {
  55                         if (act->get_reads_from()!=lastwrmap.get(act->get_location()))
  56                                 badrfset.put(act,lastwrmap.get(act->get_location()));
  57                 }
  58                 if (act->is_write())
  59                         lastwrmap.put(act->get_location(), act);
  60         }
  61 }
  62
  63 bool SCAnalysis::merge(ClockVector *cv, const ModelAction *act, const ModelAction *act2) {
  64         ClockVector * cv2=cvmap.get(act2);
  65         if (cv2==NULL)
  66                 return true;
  67         if (cv2->getClock(act->get_tid()) >= act->get_seq_number() && act->get_seq_number() != 0) {
  68                 cyclic=true;
  69                 //refuse to introduce cycles into clock vectors
  70                 return false;
  71         }
  72
  73         return cv->merge(cv2);
  74 }
  75
  76 ModelAction * SCAnalysis::getNextAction() {
  77         ModelAction *act = NULL;
  78         /* Find the earliest in SC ordering */
  79         for (int i = 0; i <= maxthreads; i++) {
  80                 action_list_t *threadlist = &threadlists[i];
  81                 if (threadlist->empty())
  82                         continue;
  83                 ModelAction *first = threadlist->front();
  84                 if (act==NULL) {
  85                         act=first;
  86                         continue;
  87                 }
  88                 ClockVector *cv = cvmap.get(act);
  89                 if (cv->synchronized_since(first)) {
  90                         act = first;
  91                 }
  92         }
  93         if (act == NULL)
  94                 return act;
  95
  96
  97         /* Find the model action with the earliest sequence number in case of a cycle.
  98          */
  99
 100         for (int i = 0; i <= maxthreads; i++) {
 101                 action_list_t *threadlist = &threadlists[i];
 102                 if (threadlist->empty())
 103                         continue;
 104                 ModelAction *first = threadlist->front();
 105                 ClockVector *cv = cvmap.get(act);
 106                 ClockVector *cvfirst = cvmap.get(first);
 107                 if (first->get_seq_number()<act->get_seq_number()&&
 108                                 (cv->synchronized_since(first)||!cvfirst->synchronized_since(act))) {
 109                         act=first;
 110                 }
 111         }
 112
 113         /* See if hb demands an earlier action. */
 114         for (int i = 0; i <= maxthreads; i++) {
 115                 action_list_t *threadlist = &threadlists[i];
 116                 if (threadlist->empty())
 117                         continue;
 118                 ModelAction *first = threadlist->front();
 119                 ClockVector *cv = act->get_cv();
 120                 if (cv->synchronized_since(first)) {
 121                         act = first;
 122                 }
 123         }
 124         return act;
 125 }
 126
 127 action_list_t * SCAnalysis::generateSC(action_list_t *list) {
 128         action_list_t *sclist = new action_list_t();
 129         while (true) {
 130                 ModelAction *act = getNextAction();
 131                 if (act == NULL)
 132                         break;
 133                 thread_id_t tid = act->get_tid();
 134                 //remove action
 135                 threadlists[id_to_int(tid)].pop_front();
 136                 //add ordering constraints from this choice
 137                 if (updateConstraints(act)) {
 138                         //propagate changes if we have them
 139                         computeCV(list);
 140                 }
 141                 //add action to end
 142                 sclist->push_back(act);
 143         }
 144         return sclist;
 145 }
 146
 147 void SCAnalysis::buildVectors(action_list_t *list) {
 148         maxthreads = 0;
 149         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 150                 ModelAction *act = *it;
 151                 int threadid = id_to_int(act->get_tid());
 152                 if (threadid > maxthreads) {
 153                         threadlists.resize(threadid + 1);
 154                         maxthreads = threadid;
 155                 }
 156                 threadlists[threadid].push_back(act);
 157         }
 158 }
 159
 160 bool SCAnalysis::updateConstraints(ModelAction *act) {
 161         bool changed = false;
 162         for (int i = 0; i <= maxthreads; i++) {
 163                 thread_id_t tid = int_to_id(i);
 164                 if (tid == act->get_tid())
 165                         continue;
 166
 167                 action_list_t *list = &threadlists[id_to_int(tid)];
 168                 for (action_list_t::iterator rit = list->begin(); rit != list->end(); rit++) {
 169                         ModelAction *write = *rit;
 170                         if (!write->is_write())
 171                                 continue;
 172                         ClockVector *writecv = cvmap.get(write);
 173                         if (writecv->synchronized_since(act))
 174                                 break;
 175                         if (write->get_location() == act->get_location()) {
 176                                 //write is sc after act
 177                                 merge(writecv, write, act);
 178                                 changed = true;
 179                                 break;
 180                         }
 181                 }
 182         }
 183         return changed;
 184 }
 185
 186 bool SCAnalysis::processRead(ModelAction *read, ClockVector *cv) {
 187         bool changed = false;
 188
 189         /* Merge in the clock vector from the write */
 190         const ModelAction *write = read->get_reads_from();
 191         ClockVector *writecv = cvmap.get(write);
 192         changed |= merge(cv, read, write) && (*read < *write);
 193
 194         for (int i = 0; i <= maxthreads; i++) {
 195                 thread_id_t tid = int_to_id(i);
 196                 if (tid == read->get_tid())
 197                         continue;
 198                 if (tid == write->get_tid())
 199                         continue;
 200                 action_list_t *list = execution->get_actions_on_obj(read->get_location(), tid);
 201                 if (list == NULL)
 202                         continue;
 203                 for (action_list_t::reverse_iterator rit = list->rbegin(); rit != list->rend(); rit++) {
 204                         ModelAction *write2 = *rit;
 205                         if (!write2->is_write())
 206                                 continue;
 207
 208                         ClockVector *write2cv = cvmap.get(write2);
 209                         if (write2cv == NULL)
 210                                 continue;
 211
 212                         /* write -sc-> write2 &&
 213                                  write -rf-> R =>
 214                                  R -sc-> write2 */
 215                         if (write2cv->synchronized_since(write)) {
 216                                 changed |= merge(write2cv, write2, read);
 217                         }
 218
 219                         //looking for earliest write2 in iteration to satisfy this
 220                         /* write2 -sc-> R &&
 221                                  write -rf-> R =>
 222                                  write2 -sc-> write */
 223                         if (cv->synchronized_since(write2)) {
 224                                 changed |= writecv==NULL || merge(writecv, write, write2);
 225                                 break;
 226                         }
 227                 }
 228         }
 229         return changed;
 230 }
 231
 232 void SCAnalysis::computeCV(action_list_t *list) {
 233         bool changed = true;
 234         bool firsttime = true;
 235         ModelAction **last_act = (ModelAction **)model_calloc(1, (maxthreads + 1) * sizeof(ModelAction *));
 236         while (changed) {
 237                 changed = changed&firsttime;
 238                 firsttime = false;
 239
 240                 for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 241                         ModelAction *act = *it;
 242                         ModelAction *lastact = last_act[id_to_int(act->get_tid())];
 243                         if (act->is_thread_start())
 244                                 lastact = execution->get_thread(act)->get_creation();
 245                         last_act[id_to_int(act->get_tid())] = act;
 246                         ClockVector *cv = cvmap.get(act);
 247                         if (cv == NULL) {
 248                                 cv = new ClockVector(NULL, act);
 249                                 cvmap.put(act, cv);
 250                         }
 251                         if (lastact != NULL) {
 252                                 merge(cv, act, lastact);
 253                         }
 254                         if (act->is_thread_join()) {
 255                                 Thread *joinedthr = act->get_thread_operand();
 256                                 ModelAction *finish = execution->get_last_action(joinedthr->get_id());
 257                                 changed |= merge(cv, act, finish);
 258                         }
 259                         if (act->is_read()) {
 260                                 changed |= processRead(act, cv);
 261                         }
 262                 }
 263                 /* Reset the last action array */
 264                 if (changed) {
 265                         bzero(last_act, (maxthreads + 1) * sizeof(ModelAction *));
 266                 }
 267         }
 268         model_free(last_act);
 269 }