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