2 #include "threads-model.h"
7 #include "concretepredicate.h"
12 #include "execution.h"
14 NewFuzzer::NewFuzzer() :
16 thrd_last_func_inst(),
17 available_branches_tmp_storage(),
18 thrd_selected_child_branch(),
21 paused_thread_table(128),
22 failed_predicates(32),
27 * @brief Register the ModelHistory and ModelExecution engine
29 void NewFuzzer::register_engine(ModelHistory * history, ModelExecution *execution)
31 this->history = history;
32 this->execution = execution;
35 int NewFuzzer::selectWrite(ModelAction *read, SnapVector<ModelAction *> * rf_set)
37 // return random() % rf_set->size();
39 thread_id_t tid = read->get_tid();
40 int thread_id = id_to_int(tid);
42 if (thrd_last_read_act.size() <= (uint) thread_id) {
43 thrd_last_read_act.resize(thread_id + 1);
44 thrd_last_func_inst.resize(thread_id + 1);
47 // A new read action is encountered, select a random child branch of current predicate
48 if (read != thrd_last_read_act[thread_id]) {
49 FuncNode * func_node = history->get_curr_func_node(tid);
50 Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
51 FuncInst * read_inst = func_node->get_inst(read);
52 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
54 if (curr_pred != NULL) {
55 Predicate * selected_branch = NULL;
57 if (check_store_visibility(curr_pred, read_inst, inst_act_map, rf_set))
58 selected_branch = selectBranch(tid, curr_pred, read_inst);
60 // no child of curr_pred matches read_inst, check back edges
61 PredSet * back_edges = curr_pred->get_backedges();
62 PredSetIter * it = back_edges->iterator();
64 while (it->hasNext()) {
65 curr_pred = it->next();
66 if (check_store_visibility(curr_pred, read_inst, inst_act_map, rf_set)) {
67 selected_branch = selectBranch(tid, curr_pred, read_inst);
75 prune_writes(tid, selected_branch, rf_set, inst_act_map);
78 if (!failed_predicates.isEmpty())
79 failed_predicates.reset();
81 thrd_last_read_act[thread_id] = read;
82 thrd_last_func_inst[thread_id] = read_inst;
85 ASSERT(rf_set->size() != 0);
86 int random_index = random() % rf_set->size();
91 /* For children of curr_pred that matches read_inst.
92 * If any store in rf_set satisfies the a child's predicate,
93 * increment the store visibility count for it.
95 * @return False if no child matches read_inst
97 bool NewFuzzer::check_store_visibility(Predicate * curr_pred, FuncInst * read_inst,
98 inst_act_map_t * inst_act_map, SnapVector<ModelAction *> * rf_set)
100 available_branches_tmp_storage.clear();
102 ASSERT(!rf_set->empty());
103 if (curr_pred == NULL || read_inst == NULL)
106 ModelVector<Predicate *> * children = curr_pred->get_children();
107 bool any_child_match = false;
109 /* Iterate over all predicate children */
110 for (uint i = 0;i < children->size();i++) {
111 Predicate * branch = (*children)[i];
113 /* The children predicates may have different FuncInsts */
114 if (branch->get_func_inst() == read_inst) {
115 PredExprSet * pred_expressions = branch->get_pred_expressions();
116 any_child_match = true;
118 branch->incr_total_checking_count();
120 if (pred_expressions->isEmpty()) {
121 /* Do not check predicate expression of unset predicates */
122 available_branches_tmp_storage.push_back(branch);
123 branch->incr_store_visible_count();
127 /* Iterate over all write actions */
128 for (uint j = 0;j < rf_set->size();j++) {
129 ModelAction * write_act = (*rf_set)[j];
130 uint64_t write_val = write_act->get_write_value();
132 bool satisfy_predicate = check_predicate_expressions(pred_expressions, inst_act_map, write_val, &dummy);
134 /* If one write value satisfies the predicate, go to check the next predicate */
135 if (satisfy_predicate) {
136 branch->incr_store_visible_count();
137 available_branches_tmp_storage.push_back(branch);
144 return any_child_match;
147 /* Select a random branch from the children of curr_pred
148 * @return The selected branch
150 Predicate * NewFuzzer::selectBranch(thread_id_t tid, Predicate * curr_pred, FuncInst * read_inst)
152 int thread_id = id_to_int(tid);
153 if ( thrd_selected_child_branch.size() <= (uint) thread_id)
154 thrd_selected_child_branch.resize(thread_id + 1);
156 if (curr_pred == NULL || read_inst == NULL) {
157 thrd_selected_child_branch[thread_id] = NULL;
161 // predicate children have not been generated
162 if (available_branches_tmp_storage.size() == 0) {
163 thrd_selected_child_branch[thread_id] = NULL;
167 int index = choose_index(&available_branches_tmp_storage);
168 Predicate * random_branch = available_branches_tmp_storage[ index ];
169 thrd_selected_child_branch[thread_id] = random_branch;
171 return random_branch;
175 * @brief Select a branch from the given predicate branch
177 int NewFuzzer::choose_index(SnapVector<Predicate *> * branches)
179 if (branches->size() == 1)
182 double total_weight = 0;
183 SnapVector<double> weights;
184 for (uint i = 0; i < branches->size(); i++) {
185 Predicate * branch = (*branches)[i];
186 double weight = branch->get_weight();
187 total_weight += weight;
188 weights.push_back(weight);
191 double prob = (double) random() / RAND_MAX;
195 for (uint i = 0; i < weights.size(); i++) {
197 prob_sum += (double) (weights[i] / total_weight);
198 if (prob_sum > prob) {
204 // return random() % branches->size();
207 Predicate * NewFuzzer::get_selected_child_branch(thread_id_t tid)
209 int thread_id = id_to_int(tid);
210 if (thrd_selected_child_branch.size() <= (uint) thread_id)
213 return thrd_selected_child_branch[thread_id];
216 /* Remove writes from the rf_set that do not satisfie the selected predicate,
217 * and store them in thrd_pruned_writes
219 * @return true if rf_set is pruned
221 bool NewFuzzer::prune_writes(thread_id_t tid, Predicate * pred,
222 SnapVector<ModelAction *> * rf_set, inst_act_map_t * inst_act_map)
227 PredExprSet * pred_expressions = pred->get_pred_expressions();
228 if (pred_expressions->getSize() == 0) // unset predicates
231 int thread_id = id_to_int(tid);
232 uint old_size = thrd_pruned_writes.size();
233 if (thrd_pruned_writes.size() <= (uint) thread_id) {
234 uint new_size = thread_id + 1;
235 thrd_pruned_writes.resize(new_size);
236 for (uint i = old_size;i < new_size;i++)
237 thrd_pruned_writes[i] = new SnapVector<ModelAction *>();
239 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
240 pruned_writes->clear(); // clear the old pruned_writes set
245 while ( index < rf_set->size() ) {
246 ModelAction * write_act = (*rf_set)[index];
247 uint64_t write_val = write_act->get_write_value();
248 bool no_predicate = false;
249 bool satisfy_predicate = check_predicate_expressions(pred_expressions, inst_act_map, write_val, &no_predicate);
254 if (!satisfy_predicate) {
255 ASSERT(rf_set != NULL);
256 (*rf_set)[index] = rf_set->back();
258 pruned_writes->push_back(write_act);
267 /* @brief Put a thread to sleep because no writes in rf_set satisfies the selected predicate.
269 * @param thread A thread whose last action is a read
271 void NewFuzzer::conditional_sleep(Thread * thread)
273 int index = paused_thread_list.size();
275 model->getScheduler()->add_sleep(thread);
276 paused_thread_list.push_back(thread);
277 paused_thread_table.put(thread, index); // Update table
279 /* Add the waiting condition to ModelHistory */
280 ModelAction * read = thread->get_pending();
281 thread_id_t tid = thread->get_id();
282 FuncNode * func_node = history->get_curr_func_node(tid);
283 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
285 Predicate * selected_branch = get_selected_child_branch(tid);
286 ConcretePredicate * concrete = selected_branch->evaluate(inst_act_map, tid);
287 concrete->set_location(read->get_location());
289 history->add_waiting_write(concrete);
290 /* history->add_waiting_thread is already called in find_threads */
293 bool NewFuzzer::has_paused_threads()
295 return paused_thread_list.size() != 0;
298 Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
300 if (numthreads == 0 && has_paused_threads()) {
301 wake_up_paused_threads(threadlist, &numthreads);
302 //model_print("list size: %d, active t id: %d\n", numthreads, threadlist[0]);
305 int random_index = random() % numthreads;
306 int thread = threadlist[random_index];
307 thread_id_t curr_tid = int_to_id(thread);
308 return execution->get_thread(curr_tid);
311 /* Force waking up one of threads paused by Fuzzer, because otherwise
312 * the Fuzzer is not making progress
314 void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
316 int random_index = random() % paused_thread_list.size();
317 Thread * thread = paused_thread_list[random_index];
318 model->getScheduler()->remove_sleep(thread);
320 Thread * last_thread = paused_thread_list.back();
321 paused_thread_list[random_index] = last_thread;
322 paused_thread_list.pop_back();
323 paused_thread_table.put(last_thread, random_index); // Update table
324 paused_thread_table.remove(thread);
326 thread_id_t tid = thread->get_id();
327 history->remove_waiting_write(tid);
328 history->remove_waiting_thread(tid);
330 threadlist[*numthreads] = tid;
334 Predicate * selected_branch = get_selected_child_branch(tid);
335 update_predicate_score(selected_branch, SLEEP_FAIL_TYPE3);
338 model_print("thread %d is woken up\n", tid);
341 /* Wake up conditional sleeping threads if the desired write is available */
342 void NewFuzzer::notify_paused_thread(Thread * thread)
344 ASSERT(paused_thread_table.contains(thread));
346 int index = paused_thread_table.get(thread);
347 model->getScheduler()->remove_sleep(thread);
349 Thread * last_thread = paused_thread_list.back();
350 paused_thread_list[index] = last_thread;
351 paused_thread_list.pop_back();
352 paused_thread_table.put(last_thread, index); // Update table
353 paused_thread_table.remove(thread);
355 thread_id_t tid = thread->get_id();
356 history->remove_waiting_write(tid);
357 history->remove_waiting_thread(tid);
360 Predicate * selected_branch = get_selected_child_branch(tid);
361 update_predicate_score(selected_branch, SLEEP_SUCCESS);
364 model_print("** thread %d is woken up\n", tid);
367 /* Find threads that may write values that the pending read action is waiting for.
368 * Side effect: waiting thread related info are stored in dist_info_vec
370 * @return True if any thread is found
372 bool NewFuzzer::find_threads(ModelAction * pending_read)
374 ASSERT(pending_read->is_read());
376 void * location = pending_read->get_location();
377 thread_id_t self_id = pending_read->get_tid();
378 bool finds_waiting_for = false;
380 SnapVector<FuncNode *> * func_node_list = history->getWrFuncNodes(location);
381 for (uint i = 0;i < func_node_list->size();i++) {
382 FuncNode * target_node = (*func_node_list)[i];
383 for (uint i = 1;i < execution->get_num_threads();i++) {
384 thread_id_t tid = int_to_id(i);
388 FuncNode * node = history->get_curr_func_node(tid);
389 /* It is possible that thread tid is not in any FuncNode */
393 int distance = node->compute_distance(target_node);
394 if (distance != -1) {
395 finds_waiting_for = true;
396 //model_print("thread: %d; distance from node %d to node %d: %d\n", tid, node->get_func_id(), target_node->get_func_id(), distance);
398 dist_info_vec.push_back(node_dist_info(tid, target_node, distance));
403 return finds_waiting_for;
406 bool NewFuzzer::check_predicate_expressions(PredExprSet * pred_expressions,
407 inst_act_map_t * inst_act_map, uint64_t write_val, bool * no_predicate)
409 bool satisfy_predicate = true;
411 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
412 while (pred_expr_it->hasNext()) {
413 struct pred_expr * expression = pred_expr_it->next();
416 switch (expression->token) {
418 *no_predicate = true;
421 FuncInst * to_be_compared;
422 ModelAction * last_act;
425 to_be_compared = expression->func_inst;
426 last_act = inst_act_map->get(to_be_compared);
427 last_read = last_act->get_reads_from_value();
429 equality = (write_val == last_read);
430 if (equality != expression->value)
431 satisfy_predicate = false;
434 // TODO: implement likely to be null
435 equality = ((void*) (write_val & 0xffffffff) == NULL);
436 if (equality != expression->value)
437 satisfy_predicate = false;
440 model_print("unknown predicate token\n");
444 if (!satisfy_predicate)
449 return satisfy_predicate;
452 bool NewFuzzer::shouldWait(const ModelAction * act)