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