newfuzzer.cc

   1 #include "newfuzzer.h"
   2 #include "threads-model.h"
   3 #include "action.h"
   4 #include "history.h"
   5 #include "funcnode.h"
   6 #include "funcinst.h"
   7 #include "predicate.h"
   8 #include "concretepredicate.h"
   9
  10 #include "model.h"
  11 #include "schedule.h"
  12 #include "execution.h"
  13
  14 NewFuzzer::NewFuzzer() :
  15         thrd_last_read_act(),
  16         thrd_curr_pred(),
  17         thrd_selected_child_branch(),
  18         thrd_pruned_writes(),
  19         paused_thread_set()
  20 {}
  21
  22 /**
  23  * @brief Register the ModelHistory and ModelExecution engine
  24  */
  25 void NewFuzzer::register_engine(ModelHistory * history, ModelExecution *execution)
  26 {
  27         this->history = history;
  28         this->execution = execution;
  29 }
  30
  31 int NewFuzzer::selectWrite(ModelAction *read, SnapVector<ModelAction *> * rf_set)
  32 {
  33 //      return random() % rf_set->size();
  34
  35         thread_id_t tid = read->get_tid();
  36         int thread_id = id_to_int(tid);
  37
  38         if (thrd_last_read_act.size() <= (uint) thread_id)
  39                 thrd_last_read_act.resize(thread_id + 1);
  40
  41         // A new read action is encountered, select a random child branch of current predicate
  42         if (read != thrd_last_read_act[thread_id]) {
  43                 thrd_last_read_act[thread_id] = read;
  44
  45                 SnapVector<func_id_list_t> * thrd_func_list = execution->get_thrd_func_list();
  46                 uint32_t func_id = (*thrd_func_list)[thread_id].back();
  47                 FuncNode * func_node = history->get_func_node(func_id);
  48                 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
  49                 Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
  50                 FuncInst * read_inst = func_node->get_inst(read);
  51
  52                 Predicate * selected_branch = selectBranch(tid, curr_pred, read_inst);
  53                 prune_writes(tid, selected_branch, rf_set, inst_act_map);
  54         }
  55
  56         // No write satisfies the selected predicate
  57         if ( rf_set->size() == 0 ) {
  58                 Thread * read_thread = execution->get_thread(tid);
  59                 model_print("the %d read action of thread %d is unsuccessful\n", read->get_seq_number(), read_thread->get_id());
  60
  61                 // reset thread pending action and revert sequence numbers
  62                 read_thread->set_pending(read);
  63                 read->reset_seq_number();
  64                 execution->restore_last_seq_num();
  65
  66                 conditional_sleep(read_thread);
  67                 return -1;
  68 /*
  69                 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
  70                 for (uint i = 0; i < pruned_writes->size(); i++)
  71                         rf_set->push_back( (*pruned_writes)[i] );
  72                 pruned_writes->clear();
  73 */
  74         }
  75
  76         ASSERT(rf_set->size() != 0);
  77         int random_index = random() % rf_set->size();
  78
  79         return random_index;
  80 }
  81
  82 /* Select a random branch from the children of curr_pred
  83  * @return The selected branch
  84  */
  85 Predicate * NewFuzzer::selectBranch(thread_id_t tid, Predicate * curr_pred, FuncInst * read_inst)
  86 {
  87         int thread_id = id_to_int(tid);
  88         if ( thrd_selected_child_branch.size() <= (uint) thread_id)
  89                 thrd_selected_child_branch.resize(thread_id + 1);
  90
  91         if (curr_pred == NULL || read_inst == NULL) {
  92                 thrd_selected_child_branch[thread_id] = NULL;
  93                 return NULL;
  94         }
  95
  96         ModelVector<Predicate *> * children = curr_pred->get_children();
  97         SnapVector<Predicate *> branches;
  98
  99         for (uint i = 0; i < children->size(); i++) {
 100                 Predicate * child = (*children)[i];
 101                 if (child->get_func_inst() == read_inst)
 102                         branches.push_back(child);
 103         }
 104
 105         // predicate children have not been generated
 106         if (branches.size() == 0) {
 107                 thrd_selected_child_branch[thread_id] = NULL;
 108                 return NULL;
 109         }
 110
 111         // randomly select a branch
 112         int random_index = random() % branches.size();
 113         Predicate * random_branch = branches[ random_index ];
 114         thrd_selected_child_branch[thread_id] = random_branch;
 115
 116         return random_branch;
 117 }
 118
 119 Predicate * NewFuzzer::get_selected_child_branch(thread_id_t tid)
 120 {
 121         int thread_id = id_to_int(tid);
 122         if (thrd_selected_child_branch.size() <= (uint) thread_id)
 123                 return NULL;
 124
 125         return thrd_selected_child_branch[thread_id];
 126 }
 127
 128 /* Remove writes from the rf_set that do not satisfie the selected predicate,
 129  * and store them in thrd_pruned_writes
 130  *
 131  * @return true if rf_set is pruned
 132  */
 133 bool NewFuzzer::prune_writes(thread_id_t tid, Predicate * pred,
 134         SnapVector<ModelAction *> * rf_set, inst_act_map_t * inst_act_map)
 135 {
 136         if (pred == NULL)
 137                 return false;
 138
 139         PredExprSet * pred_expressions = pred->get_pred_expressions();
 140         if (pred_expressions->getSize() == 0)   // unset predicates
 141                 return false;
 142
 143         int thread_id = id_to_int(tid);
 144         uint old_size = thrd_pruned_writes.size();
 145         if (thrd_pruned_writes.size() <= (uint) thread_id) {
 146                 uint new_size = thread_id + 1;
 147                 thrd_pruned_writes.resize(new_size);
 148                 for (uint i = old_size; i < new_size; i++)
 149                         thrd_pruned_writes[i] = new SnapVector<ModelAction *>();
 150         }
 151         SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
 152         pruned_writes->clear(); // clear the old pruned_writes set
 153
 154         bool pruned = false;
 155         uint index = 0;
 156
 157         ConcretePredicate * concrete_pred = pred->evaluate(inst_act_map, tid);
 158         SnapVector<struct concrete_pred_expr> * concrete_exprs = concrete_pred->getExpressions();
 159
 160         while ( index < rf_set->size() ) {
 161                 ModelAction * write_act = (*rf_set)[index];
 162                 uint64_t write_val = write_act->get_write_value();
 163                 bool satisfy_predicate = true;
 164
 165                 for (uint i = 0; i < concrete_exprs->size(); i++) {
 166                         struct concrete_pred_expr concrete = (*concrete_exprs)[i];
 167                         bool equality;
 168
 169                         switch (concrete.token) {
 170                                 case NOPREDICATE:
 171                                         return false;
 172                                 case EQUALITY:
 173                                         equality = (write_val == concrete.value);
 174                                         if (equality != concrete.equality)
 175                                                 satisfy_predicate = false;
 176                                         break;
 177                                 case NULLITY:
 178                                         equality = ((void*)write_val == NULL);
 179                                         if (equality != concrete.equality)
 180                                                 satisfy_predicate = false;
 181                                         break;
 182                                 default:
 183                                         model_print("unknown predicate token\n");
 184                                         break;
 185                         }
 186
 187                         if (!satisfy_predicate)
 188                                 break;
 189                 }
 190
 191                 if (!satisfy_predicate) {
 192                         ASSERT(rf_set != NULL);
 193                         (*rf_set)[index] = rf_set->back();
 194                         rf_set->pop_back();
 195                         pruned_writes->push_back(write_act);
 196                         pruned = true;
 197                 } else
 198                         index++;
 199         }
 200
 201         return pruned;
 202 }
 203
 204 /* @brief Put a thread to sleep because no writes in rf_set satisfies the selected predicate.
 205  *
 206  * @param thread A thread whose last action is a read
 207  */
 208 void NewFuzzer::conditional_sleep(Thread * thread)
 209 {
 210         model->getScheduler()->add_sleep(thread);
 211         paused_thread_set.push_back(thread);
 212 }
 213
 214 bool NewFuzzer::has_paused_threads()
 215 {
 216         return paused_thread_set.size() != 0;
 217 }
 218
 219 Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
 220 {
 221         if (numthreads == 0 && has_paused_threads()) {
 222                 wake_up_paused_threads(threadlist, &numthreads);
 223                 model_print("list size: %d\n", numthreads);
 224                 model_print("active t id: %d\n", threadlist[0]);
 225         }
 226
 227         int random_index = random() % numthreads;
 228         int thread = threadlist[random_index];
 229         thread_id_t curr_tid = int_to_id(thread);
 230         return model->get_thread(curr_tid);
 231 }
 232
 233 /* Force waking up one of threads paused by Fuzzer */
 234 void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
 235 {
 236         int random_index = random() % paused_thread_set.size();
 237         Thread * thread = paused_thread_set[random_index];
 238         model->getScheduler()->remove_sleep(thread);
 239
 240         paused_thread_set[random_index] = paused_thread_set.back();
 241         paused_thread_set.pop_back();
 242
 243         model_print("thread %d is woken up\n", thread->get_id());
 244         threadlist[*numthreads] = thread->get_id();
 245         (*numthreads)++;
 246 }
 247
 248 /* Notify one of conditional sleeping threads if the desired write is available */
 249 bool NewFuzzer::notify_conditional_sleep(Thread * thread)
 250 {
 251
 252 }
 253
 254 bool NewFuzzer::shouldWait(const ModelAction * act)
 255 {
 256         return random() & 1;
 257 }