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         buildVectors(actions);
  44         computeCV(actions);
  45         action_list_t *list = generateSC(actions);
  46         check_rf(list);
  47         print_list(list);
  48 }
  49
  50 void SCAnalysis::check_rf(action_list_t *list) {
  51         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
  52                 const ModelAction *act = *it;
  53                 if (act->is_read()) {
  54                         if (act->get_reads_from()!=lastwrmap.get(act->get_location()))
  55                                 badrfset.put(act,lastwrmap.get(act->get_location()));
  56                 }
  57                 if (act->is_write())
  58                         lastwrmap.put(act->get_location(), act);
  59         }
  60 }
  61
  62 bool SCAnalysis::merge(ClockVector *cv, const ModelAction *act, const ModelAction *act2) {
  63         ClockVector * cv2=cvmap.get(act2);
  64         if (cv2==NULL)
  65                 return true;
  66         if (cv2->getClock(act->get_tid()) >= act->get_seq_number() && act->get_seq_number() != 0) {
  67                 cyclic=true;
  68                 //refuse to introduce cycles into clock vectors
  69                 return false;
  70         }
  71
  72         return cv->merge(cv2);
  73 }
  74
  75 ModelAction * SCAnalysis::getNextAction() {
  76         ModelAction *act = NULL;
  77         /* Find the earliest in SC ordering */
  78         for (int i = 0; i <= maxthreads; i++) {
  79                 action_list_t *threadlist = &threadlists[i];
  80                 if (threadlist->empty())
  81                         continue;
  82                 ModelAction *first = threadlist->front();
  83                 if (act==NULL) {
  84                         act = first;
  85                         continue;
  86                 }
  87                 ClockVector *cv = cvmap.get(act);
  88                 if (cv->synchronized_since(first)) {
  89                         act = first;
  90                 }
  91         }
  92         if (act == NULL)
  93                 return act;
  94
  95         /* Find the model action with the earliest sequence number in case of a cycle.
  96          */
  97
  98         for (int i = 0; i <= maxthreads; i++) {
  99                 action_list_t *threadlist = &threadlists[i];
 100                 if (threadlist->empty())
 101                         continue;
 102                 ModelAction *first = threadlist->front();
 103                 ClockVector *cvfirst = cvmap.get(first);
 104                 if (first->get_seq_number()<act->get_seq_number()) {
 105                         bool candidate=true;
 106                         for (int j = 0; j <= maxthreads; j++) {
 107                                 action_list_t *threadlist2 = &threadlists[j];
 108                                 if (threadlist2->empty())
 109                                         continue;
 110                                 ModelAction *check = threadlist2->front();
 111                                 if ((check!=first) &&
 112                                                 cvfirst->synchronized_since(check)) {
 113                                         candidate=false;
 114                                         break;
 115                                 }
 116                         }
 117                         if (candidate)
 118                                 act=first;
 119                 }
 120         }
 121
 122         /* See if hb demands an earlier action. */
 123         for (int i = 0; i <= maxthreads; i++) {
 124                 action_list_t *threadlist = &threadlists[i];
 125                 if (threadlist->empty())
 126                         continue;
 127                 ModelAction *first = threadlist->front();
 128                 ClockVector *cv = act->get_cv();
 129                 if (cv->synchronized_since(first)) {
 130                         act = first;
 131                 }
 132         }
 133         return act;
 134 }
 135
 136 action_list_t * SCAnalysis::generateSC(action_list_t *list) {
 137         action_list_t *sclist = new action_list_t();
 138         while (true) {
 139                 ModelAction *act = getNextAction();
 140                 if (act == NULL)
 141                         break;
 142                 thread_id_t tid = act->get_tid();
 143                 //remove action
 144                 threadlists[id_to_int(tid)].pop_front();
 145                 //add ordering constraints from this choice
 146                 if (updateConstraints(act)) {
 147                         //propagate changes if we have them
 148                         computeCV(list);
 149                 }
 150                 //add action to end
 151                 sclist->push_back(act);
 152         }
 153         return sclist;
 154 }
 155
 156 void SCAnalysis::buildVectors(action_list_t *list) {
 157         maxthreads = 0;
 158         for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 159                 ModelAction *act = *it;
 160                 int threadid = id_to_int(act->get_tid());
 161                 if (threadid > maxthreads) {
 162                         threadlists.resize(threadid + 1);
 163                         maxthreads = threadid;
 164                 }
 165                 threadlists[threadid].push_back(act);
 166         }
 167 }
 168
 169 bool SCAnalysis::updateConstraints(ModelAction *act) {
 170         bool changed = false;
 171         for (int i = 0; i <= maxthreads; i++) {
 172                 thread_id_t tid = int_to_id(i);
 173                 if (tid == act->get_tid())
 174                         continue;
 175
 176                 action_list_t *list = &threadlists[id_to_int(tid)];
 177                 for (action_list_t::iterator rit = list->begin(); rit != list->end(); rit++) {
 178                         ModelAction *write = *rit;
 179                         if (!write->is_write())
 180                                 continue;
 181                         ClockVector *writecv = cvmap.get(write);
 182                         if (writecv->synchronized_since(act))
 183                                 break;
 184                         if (write->get_location() == act->get_location()) {
 185                                 //write is sc after act
 186                                 merge(writecv, write, act);
 187                                 changed = true;
 188                                 break;
 189                         }
 190                 }
 191         }
 192         return changed;
 193 }
 194
 195 bool SCAnalysis::processRead(ModelAction *read, ClockVector *cv) {
 196         bool changed = false;
 197
 198         /* Merge in the clock vector from the write */
 199         const ModelAction *write = read->get_reads_from();
 200         ClockVector *writecv = cvmap.get(write);
 201         changed |= merge(cv, read, write) && (*read < *write);
 202
 203         for (int i = 0; i <= maxthreads; i++) {
 204                 thread_id_t tid = int_to_id(i);
 205                 if (tid == read->get_tid())
 206                         continue;
 207                 if (tid == write->get_tid())
 208                         continue;
 209                 action_list_t *list = execution->get_actions_on_obj(read->get_location(), tid);
 210                 if (list == NULL)
 211                         continue;
 212                 for (action_list_t::reverse_iterator rit = list->rbegin(); rit != list->rend(); rit++) {
 213                         ModelAction *write2 = *rit;
 214                         if (!write2->is_write())
 215                                 continue;
 216
 217                         ClockVector *write2cv = cvmap.get(write2);
 218                         if (write2cv == NULL)
 219                                 continue;
 220
 221                         /* write -sc-> write2 &&
 222                                  write -rf-> R =>
 223                                  R -sc-> write2 */
 224                         if (write2cv->synchronized_since(write)) {
 225                                 changed |= merge(write2cv, write2, read);
 226                         }
 227
 228                         //looking for earliest write2 in iteration to satisfy this
 229                         /* write2 -sc-> R &&
 230                                  write -rf-> R =>
 231                                  write2 -sc-> write */
 232                         if (cv->synchronized_since(write2)) {
 233                                 changed |= writecv==NULL || merge(writecv, write, write2);
 234                                 break;
 235                         }
 236                 }
 237         }
 238         return changed;
 239 }
 240
 241 void SCAnalysis::computeCV(action_list_t *list) {
 242         bool changed = true;
 243         bool firsttime = true;
 244         ModelAction **last_act = (ModelAction **)model_calloc(1, (maxthreads + 1) * sizeof(ModelAction *));
 245         while (changed) {
 246                 changed = changed&firsttime;
 247                 firsttime = false;
 248
 249                 for (action_list_t::iterator it = list->begin(); it != list->end(); it++) {
 250                         ModelAction *act = *it;
 251                         ModelAction *lastact = last_act[id_to_int(act->get_tid())];
 252                         if (act->is_thread_start())
 253                                 lastact = execution->get_thread(act)->get_creation();
 254                         last_act[id_to_int(act->get_tid())] = act;
 255                         ClockVector *cv = cvmap.get(act);
 256                         if (cv == NULL) {
 257                                 cv = new ClockVector(NULL, act);
 258                                 cvmap.put(act, cv);
 259                         }
 260                         if (lastact != NULL) {
 261                                 merge(cv, act, lastact);
 262                         }
 263                         if (act->is_thread_join()) {
 264                                 Thread *joinedthr = act->get_thread_operand();
 265                                 ModelAction *finish = execution->get_last_action(joinedthr->get_id());
 266                                 changed |= merge(cv, act, finish);
 267                         }
 268                         if (act->is_read()) {
 269                                 changed |= processRead(act, cv);
 270                         }
 271                 }
 272                 /* Reset the last action array */
 273                 if (changed) {
 274                         bzero(last_act, (maxthreads + 1) * sizeof(ModelAction *));
 275                 }
 276         }
 277         model_free(last_act);
 278 }