newfuzzer.cc

   1 #include "newfuzzer.h"
   2 #include "threads-model.h"
   3 #include "model.h"
   4 #include "action.h"
   5 #include "execution.h"
   6 #include "funcnode.h"
   7 #include "schedule.h"
   8
   9 NewFuzzer::NewFuzzer() :
  10         thrd_last_read_act(),
  11         thrd_curr_pred(),
  12         thrd_selected_child_branch(),
  13         thrd_pruned_writes(),
  14         paused_thread_set()
  15 {}
  16
  17 /**
  18  * @brief Register the ModelHistory and ModelExecution engine
  19  */
  20 void NewFuzzer::register_engine(ModelHistory * history, ModelExecution *execution)
  21 {
  22         this->history = history;
  23         this->execution = execution;
  24 }
  25
  26 int NewFuzzer::selectWrite(ModelAction *read, SnapVector<ModelAction *> * rf_set)
  27 {
  28 //      return random() % rf_set->size();
  29
  30         thread_id_t tid = read->get_tid();
  31         int thread_id = id_to_int(tid);
  32
  33         if (thrd_last_read_act.size() <= (uint) thread_id)
  34                 thrd_last_read_act.resize(thread_id + 1);
  35
  36         // A new read action is encountered, select a random child branch of current predicate
  37         if (read != thrd_last_read_act[thread_id]) {
  38                 thrd_last_read_act[thread_id] = read;
  39
  40                 SnapVector<func_id_list_t> * thrd_func_list = execution->get_thrd_func_list();
  41                 uint32_t func_id = (*thrd_func_list)[thread_id].back();
  42                 FuncNode * func_node = history->get_func_node(func_id);
  43                 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
  44                 Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
  45                 FuncInst * read_inst = func_node->get_inst(read);
  46
  47                 Predicate * selected_branch = selectBranch(tid, curr_pred, read_inst);
  48                 prune_writes(tid, selected_branch, rf_set, inst_act_map);
  49         }
  50
  51         // No write satisfies the selected predicate
  52         if ( rf_set->size() == 0 ) {
  53                 Thread * read_thread = execution->get_thread(tid);
  54                 model_print("the %d read action of thread %d is unsuccessful\n", read->get_seq_number(), read_thread->get_id());
  55
  56                 // reset thread pending action and revert sequence numbers
  57                 read_thread->set_pending(read);
  58                 read->reset_seq_number();
  59                 execution->restore_last_seq_num();
  60
  61                 conditional_sleep(read_thread);
  62                 return -1;
  63 /*
  64                 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
  65                 for (uint i = 0; i < pruned_writes->size(); i++)
  66                         rf_set->push_back( (*pruned_writes)[i] );
  67                 pruned_writes->clear();
  68 */
  69         }
  70
  71         ASSERT(rf_set->size() != 0);
  72         int random_index = random() % rf_set->size();
  73
  74         return random_index;
  75 }
  76
  77 /* Select a random branch from the children of curr_pred
  78  * @return The selected branch
  79  */
  80 Predicate * NewFuzzer::selectBranch(thread_id_t tid, Predicate * curr_pred, FuncInst * read_inst)
  81 {
  82         int thread_id = id_to_int(tid);
  83         if ( thrd_selected_child_branch.size() <= (uint) thread_id)
  84                 thrd_selected_child_branch.resize(thread_id + 1);
  85
  86         if (curr_pred == NULL || read_inst == NULL) {
  87                 thrd_selected_child_branch[thread_id] = NULL;
  88                 return NULL;
  89         }
  90
  91         ModelVector<Predicate *> * children = curr_pred->get_children();
  92         SnapVector<Predicate *> branches;
  93
  94         for (uint i = 0; i < children->size(); i++) {
  95                 Predicate * child = (*children)[i];
  96                 if (child->get_func_inst() == read_inst)
  97                         branches.push_back(child);
  98         }
  99
 100         // predicate children have not been generated
 101         if (branches.size() == 0) {
 102                 thrd_selected_child_branch[thread_id] = NULL;
 103                 return NULL;
 104         }
 105
 106         // randomly select a branch
 107         int random_index = random() % branches.size();
 108         Predicate * random_branch = branches[ random_index ];
 109         thrd_selected_child_branch[thread_id] = random_branch;
 110
 111         return random_branch;
 112 }
 113
 114 Predicate * NewFuzzer::get_selected_child_branch(thread_id_t tid)
 115 {
 116         int thread_id = id_to_int(tid);
 117         if (thrd_selected_child_branch.size() <= (uint) thread_id)
 118                 return NULL;
 119
 120         return thrd_selected_child_branch[thread_id];
 121 }
 122
 123 /* Remove writes from the rf_set that do not satisfie the selected predicate,
 124  * and store them in thrd_pruned_writes
 125  *
 126  * @return true if rf_set is pruned
 127  */
 128 bool NewFuzzer::prune_writes(thread_id_t tid, Predicate * pred,
 129         SnapVector<ModelAction *> * rf_set, inst_act_map_t * inst_act_map)
 130 {
 131         if (pred == NULL)
 132                 return false;
 133
 134         PredExprSet * pred_expressions = pred->get_pred_expressions();
 135         if (pred_expressions->getSize() == 0)   // unset predicates
 136                 return false;
 137
 138         int thread_id = id_to_int(tid);
 139         uint old_size = thrd_pruned_writes.size();
 140         if (thrd_pruned_writes.size() <= (uint) thread_id) {
 141                 uint new_size = thread_id + 1;
 142                 thrd_pruned_writes.resize(new_size);
 143                 for (uint i = old_size; i < new_size; i++)
 144                         thrd_pruned_writes[i] = new SnapVector<ModelAction *>();
 145         }
 146         SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
 147         pruned_writes->clear(); // clear the old pruned_writes set
 148
 149         bool pruned = false;
 150         uint index = 0;
 151         SnapVector<struct concrete_pred_expr> concrete_exprs = pred->evaluate(inst_act_map);
 152
 153         while ( index < rf_set->size() ) {
 154                 ModelAction * write_act = (*rf_set)[index];
 155                 uint64_t write_val = write_act->get_write_value();
 156                 bool satisfy_predicate = true;
 157
 158                 for (uint i = 0; i < concrete_exprs.size(); i++) {
 159                         struct concrete_pred_expr concrete = concrete_exprs[i];
 160                         bool equality;
 161
 162                         switch (concrete.token) {
 163                                 case NOPREDICATE:
 164                                         return false;
 165                                 case EQUALITY:
 166                                         equality = (write_val == concrete.value);
 167                                         if (equality != concrete.equality)
 168                                                 satisfy_predicate = false;
 169                                         break;
 170                                 case NULLITY:
 171                                         equality = ((void*)write_val == NULL);
 172                                         if (equality != concrete.equality)
 173                                                 satisfy_predicate = false;
 174                                         break;
 175                                 default:
 176                                         model_print("unknown predicate token\n");
 177                                         break;
 178                         }
 179
 180                         if (!satisfy_predicate)
 181                                 break;
 182                 }
 183
 184                 if (!satisfy_predicate) {
 185                         ASSERT(rf_set != NULL);
 186                         (*rf_set)[index] = rf_set->back();
 187                         rf_set->pop_back();
 188                         pruned_writes->push_back(write_act);
 189                         pruned = true;
 190                 } else
 191                         index++;
 192         }
 193
 194         return pruned;
 195 }
 196
 197 /* @brief Put a thread to sleep because no writes in rf_set satisfies the selected predicate.
 198  *
 199  * @param thread A thread whose last action is a read
 200  */
 201 void NewFuzzer::conditional_sleep(Thread * thread)
 202 {
 203         model->getScheduler()->add_sleep(thread);
 204         paused_thread_set.push_back(thread);
 205 }
 206
 207 bool NewFuzzer::has_paused_threads()
 208 {
 209         return paused_thread_set.size() != 0;
 210 }
 211
 212 Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
 213 {
 214         if (numthreads == 0 && has_paused_threads()) {
 215                 wake_up_paused_threads(threadlist, &numthreads);
 216                 model_print("list size: %d\n", numthreads);
 217                 model_print("active t id: %d\n", threadlist[0]);
 218         }
 219
 220         int random_index = random() % numthreads;
 221         int thread = threadlist[random_index];
 222         thread_id_t curr_tid = int_to_id(thread);
 223         return model->get_thread(curr_tid);
 224 }
 225
 226 /* Force waking up one of threads paused by Fuzzer */
 227 void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
 228 {
 229         int random_index = random() % paused_thread_set.size();
 230         Thread * thread = paused_thread_set[random_index];
 231         model->getScheduler()->remove_sleep(thread);
 232
 233         paused_thread_set[random_index] = paused_thread_set.back();
 234         paused_thread_set.pop_back();
 235
 236         model_print("thread %d is woken up\n", thread->get_id());
 237         threadlist[*numthreads] = thread->get_id();
 238         (*numthreads)++;
 239 }
 240
 241 /* Notify one of conditional sleeping threads if the desired write is available */
 242 bool NewFuzzer::notify_conditional_sleep(Thread * thread)
 243 {
 244
 245 }
 246
 247 bool NewFuzzer::shouldWait(const ModelAction * act)
 248 {
 249         return random() & 1;
 250 }