+
+/* @brief Put a thread to sleep because no writes in rf_set satisfies the selected predicate.
+ *
+ * @param thread A thread whose last action is a read
+ */
+void NewFuzzer::conditional_sleep(Thread * thread)
+{
+ int index = paused_thread_list.size();
+
+ model->getScheduler()->add_sleep(thread);
+ paused_thread_list.push_back(thread);
+ paused_thread_table.put(thread, index); // Update table
+
+ /* Add the waiting condition to ModelHistory */
+ ModelAction * read = thread->get_pending();
+ thread_id_t tid = thread->get_id();
+ FuncNode * func_node = history->get_curr_func_node(tid);
+ inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
+
+ Predicate * selected_branch = get_selected_child_branch(tid);
+ ConcretePredicate * concrete = selected_branch->evaluate(inst_act_map, tid);
+ concrete->set_location(read->get_location());
+
+ history->add_waiting_write(concrete);
+ /* history->add_waiting_thread is already called in find_threads */
+}
+
+/**
+ * Decides whether a thread should condition sleep based on
+ * the sleep score of the chosen predicate.
+ *
+ * sleep_score = 0: never sleeps
+ * sleep_score = 100: always sleeps
+ **/
+bool NewFuzzer::should_conditional_sleep(Predicate * predicate)
+{
+ return false;
+ /*
+ int sleep_score = predicate->get_sleep_score();
+ int random_num = random() % 100;
+
+ // should sleep if random_num falls within [0, sleep_score)
+ if (random_num < sleep_score)
+ return true;
+
+ return false;
+ */
+}
+
+bool NewFuzzer::has_paused_threads()
+{
+ return paused_thread_list.size() != 0;
+}
+
+Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
+{
+ if (numthreads == 0 && has_paused_threads()) {
+ wake_up_paused_threads(threadlist, &numthreads);
+ //model_print("list size: %d, active t id: %d\n", numthreads, threadlist[0]);
+ }
+
+ int random_index = random() % numthreads;
+ int thread = threadlist[random_index];
+ thread_id_t curr_tid = int_to_id(thread);
+ return execution->get_thread(curr_tid);
+}
+
+/* Force waking up one of threads paused by Fuzzer, because otherwise
+ * the Fuzzer is not making progress
+ */
+void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
+{
+ int random_index = random() % paused_thread_list.size();
+ Thread * thread = paused_thread_list[random_index];
+ model->getScheduler()->remove_sleep(thread);
+
+ Thread * last_thread = paused_thread_list.back();
+ paused_thread_list[random_index] = last_thread;
+ paused_thread_list.pop_back();
+ paused_thread_table.put(last_thread, random_index); // Update table
+ paused_thread_table.remove(thread);
+
+ thread_id_t tid = thread->get_id();
+ history->remove_waiting_write(tid);
+ history->remove_waiting_thread(tid);
+
+ threadlist[*numthreads] = tid;
+ (*numthreads)++;
+
+/*--
+ Predicate * selected_branch = get_selected_child_branch(tid);
+ update_predicate_score(selected_branch, SLEEP_FAIL_TYPE3);
+*/
+
+ model_print("thread %d is woken up\n", tid);
+}
+
+/* Wake up conditional sleeping threads if the desired write is available */
+void NewFuzzer::notify_paused_thread(Thread * thread)
+{
+ ASSERT(paused_thread_table.contains(thread));
+
+ int index = paused_thread_table.get(thread);
+ model->getScheduler()->remove_sleep(thread);
+
+ Thread * last_thread = paused_thread_list.back();
+ paused_thread_list[index] = last_thread;
+ paused_thread_list.pop_back();
+ paused_thread_table.put(last_thread, index); // Update table
+ paused_thread_table.remove(thread);
+
+ thread_id_t tid = thread->get_id();
+ history->remove_waiting_write(tid);
+ history->remove_waiting_thread(tid);
+
+/*--
+ Predicate * selected_branch = get_selected_child_branch(tid);
+ update_predicate_score(selected_branch, SLEEP_SUCCESS);
+*/
+
+ model_print("** thread %d is woken up\n", tid);
+}
+
+/* Find threads that may write values that the pending read action is waiting for.
+ * Side effect: waiting thread related info are stored in dist_info_vec
+ *
+ * @return True if any thread is found
+ */
+bool NewFuzzer::find_threads(ModelAction * pending_read)
+{
+ ASSERT(pending_read->is_read());
+
+ void * location = pending_read->get_location();
+ thread_id_t self_id = pending_read->get_tid();
+ bool finds_waiting_for = false;
+
+ SnapVector<FuncNode *> * func_node_list = history->getWrFuncNodes(location);
+ for (uint i = 0; i < func_node_list->size(); i++) {
+ FuncNode * target_node = (*func_node_list)[i];
+ for (uint i = 1; i < execution->get_num_threads(); i++) {
+ thread_id_t tid = int_to_id(i);
+ if (tid == self_id)
+ continue;
+
+ FuncNode * node = history->get_curr_func_node(tid);
+ /* It is possible that thread tid is not in any FuncNode */
+ if (node == NULL)
+ continue;
+
+ int distance = node->compute_distance(target_node);
+ if (distance != -1) {
+ finds_waiting_for = true;
+ //model_print("thread: %d; distance from node %d to node %d: %d\n", tid, node->get_func_id(), target_node->get_func_id(), distance);
+
+ dist_info_vec.push_back(node_dist_info(tid, target_node, distance));
+ }
+ }
+ }
+
+ return finds_waiting_for;
+}
+
+/* Update predicate counts and scores (asynchronous) when the read value is not available
+ *
+ * @param type
+ * type 1: find_threads return false
+ * type 2: find_threads return true, but the fuzzer decides that that thread shall not sleep based on sleep score
+ * type 3: threads are put to sleep but woken up before the waited value appears
+ * type 4: threads are put to sleep and the waited vaule appears (success)
+ */
+
+/*--
+void NewFuzzer::update_predicate_score(Predicate * predicate, sleep_result_t type)
+{
+ switch (type) {
+ case SLEEP_FAIL_TYPE1:
+ predicate->incr_fail_count();
+
+ // Do not choose this predicate when reselecting a new branch
+ failed_predicates.put(predicate, true);
+ break;
+ case SLEEP_FAIL_TYPE2:
+ predicate->incr_fail_count();
+ predicate->incr_sleep_score(1);
+ failed_predicates.put(predicate, true);
+ break;
+ case SLEEP_FAIL_TYPE3:
+ predicate->incr_fail_count();
+ predicate->decr_sleep_score(10);
+ break;
+ case SLEEP_SUCCESS:
+ predicate->incr_sleep_score(10);
+ break;
+ default:
+ model_print("unknown predicate result type.\n");
+ break;
+ }
+}
+*/
+
+bool NewFuzzer::check_predicate_expressions(PredExprSet * pred_expressions,
+ inst_act_map_t * inst_act_map, uint64_t write_val, bool * no_predicate)
+{
+ bool satisfy_predicate = true;
+
+ PredExprSetIter * pred_expr_it = pred_expressions->iterator();
+ while (pred_expr_it->hasNext()) {
+ struct pred_expr * expression = pred_expr_it->next();
+ bool equality;
+
+ switch (expression->token) {
+ case NOPREDICATE:
+ *no_predicate = true;
+ break;
+ case EQUALITY:
+ FuncInst * to_be_compared;
+ ModelAction * last_act;
+ uint64_t last_read;
+
+ to_be_compared = expression->func_inst;
+ last_act = inst_act_map->get(to_be_compared);
+ last_read = last_act->get_reads_from_value();
+
+ equality = (write_val == last_read);
+ if (equality != expression->value)
+ satisfy_predicate = false;
+ break;
+ case NULLITY:
+ equality = ((void*)write_val == NULL);
+ if (equality != expression->value)
+ satisfy_predicate = false;
+ break;
+ default:
+ model_print("unknown predicate token\n");
+ break;
+ }
+
+ if (!satisfy_predicate)
+ break;
+ }
+
+ return satisfy_predicate;
+}
+
+bool NewFuzzer::shouldWait(const ModelAction * act)
+{
+ return random() & 1;
+}