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 // The chosen branch fails, reselect new branches
86 while ( rf_set->size() == 0 ) {
87 Predicate * selected_branch = get_selected_child_branch(tid);
88 failed_predicates.put(selected_branch, true);
90 //model_print("the %d read action of thread %d at %p is unsuccessful\n", read->get_seq_number(), read_thread->get_id(), read->get_location());
92 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
93 for (uint i = 0; i < pruned_writes->size(); i++) {
94 rf_set->push_back( (*pruned_writes)[i] );
97 // Reselect a predicate and prune writes
98 Predicate * curr_pred = selected_branch->get_parent();
99 FuncInst * read_inst = thrd_last_func_inst[thread_id];
100 selected_branch = selectBranch(tid, curr_pred, read_inst);
102 FuncNode * func_node = history->get_curr_func_node(tid);
103 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
104 prune_writes(tid, selected_branch, rf_set, inst_act_map);
106 ASSERT(selected_branch);
109 int random_index = random() % rf_set->size();
114 /* For children of curr_pred that matches read_inst.
115 * If any store in rf_set satisfies the a child's predicate,
116 * increment the store visibility count for it.
118 * @return False if no child matches read_inst
120 bool NewFuzzer::check_store_visibility(Predicate * curr_pred, FuncInst * read_inst,
121 inst_act_map_t * inst_act_map, SnapVector<ModelAction *> * rf_set)
123 available_branches_tmp_storage.clear();
125 ASSERT(!rf_set->empty());
126 if (curr_pred == NULL || read_inst == NULL)
129 ModelVector<Predicate *> * children = curr_pred->get_children();
130 bool any_child_match = false;
132 /* Iterate over all predicate children */
133 for (uint i = 0;i < children->size();i++) {
134 Predicate * branch = (*children)[i];
136 /* The children predicates may have different FuncInsts */
137 if (branch->get_func_inst() == read_inst) {
138 any_child_match = true;
139 available_branches_tmp_storage.push_back(branch);
143 return any_child_match;
146 /* Select a random branch from the children of curr_pred
147 * @return The selected branch
149 Predicate * NewFuzzer::selectBranch(thread_id_t tid, Predicate * curr_pred, FuncInst * read_inst)
151 int thread_id = id_to_int(tid);
152 if ( thrd_selected_child_branch.size() <= (uint) thread_id)
153 thrd_selected_child_branch.resize(thread_id + 1);
155 if (curr_pred == NULL || read_inst == NULL) {
156 thrd_selected_child_branch[thread_id] = NULL;
160 // predicate children have not been generated
161 if (available_branches_tmp_storage.size() == 0) {
162 thrd_selected_child_branch[thread_id] = NULL;
166 int index = choose_branch_index(&available_branches_tmp_storage);
167 Predicate * random_branch = available_branches_tmp_storage[ index ];
168 thrd_selected_child_branch[thread_id] = random_branch;
170 /* Remove the chosen branch from vec in case that this
171 * branch fails and need to choose another one */
172 available_branches_tmp_storage[index] = available_branches_tmp_storage.back();
173 available_branches_tmp_storage.pop_back();
175 return random_branch;
179 * @brief Select a branch from the given predicate branch
181 int NewFuzzer::choose_branch_index(SnapVector<Predicate *> * branches)
183 if (branches->size() == 1)
186 double total_weight = 0;
187 SnapVector<double> weights;
188 for (uint i = 0; i < branches->size(); i++) {
189 Predicate * branch = (*branches)[i];
190 double weight = branch->get_weight();
191 total_weight += weight;
192 weights.push_back(weight);
195 double prob = (double) random() / RAND_MAX;
199 for (uint i = 0; i < weights.size(); i++) {
201 prob_sum += (double) (weights[i] / total_weight);
202 if (prob_sum > prob) {
208 // return random() % branches->size();
211 Predicate * NewFuzzer::get_selected_child_branch(thread_id_t tid)
213 int thread_id = id_to_int(tid);
214 if (thrd_selected_child_branch.size() <= (uint) thread_id)
217 return thrd_selected_child_branch[thread_id];
220 /* Remove writes from the rf_set that do not satisfie the selected predicate,
221 * and store them in thrd_pruned_writes
223 * @return true if rf_set is pruned
225 bool NewFuzzer::prune_writes(thread_id_t tid, Predicate * pred,
226 SnapVector<ModelAction *> * rf_set, inst_act_map_t * inst_act_map)
231 PredExprSet * pred_expressions = pred->get_pred_expressions();
232 if (pred_expressions->getSize() == 0) // unset predicates
235 int thread_id = id_to_int(tid);
236 uint old_size = thrd_pruned_writes.size();
237 if (thrd_pruned_writes.size() <= (uint) thread_id) {
238 uint new_size = thread_id + 1;
239 thrd_pruned_writes.resize(new_size);
240 for (uint i = old_size;i < new_size;i++)
241 thrd_pruned_writes[i] = new SnapVector<ModelAction *>();
243 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
244 pruned_writes->clear(); // clear the old pruned_writes set
249 while ( index < rf_set->size() ) {
250 ModelAction * write_act = (*rf_set)[index];
251 uint64_t write_val = write_act->get_write_value();
252 bool no_predicate = false;
253 bool satisfy_predicate = check_predicate_expressions(pred_expressions, inst_act_map, write_val, &no_predicate);
258 if (!satisfy_predicate) {
259 ASSERT(rf_set != NULL);
260 (*rf_set)[index] = rf_set->back();
262 pruned_writes->push_back(write_act);
271 /* @brief Put a thread to sleep because no writes in rf_set satisfies the selected predicate.
273 * @param thread A thread whose last action is a read
275 void NewFuzzer::conditional_sleep(Thread * thread)
277 int index = paused_thread_list.size();
279 model->getScheduler()->add_sleep(thread);
280 paused_thread_list.push_back(thread);
281 paused_thread_table.put(thread, index); // Update table
283 /* Add the waiting condition to ModelHistory */
284 ModelAction * read = thread->get_pending();
285 thread_id_t tid = thread->get_id();
286 FuncNode * func_node = history->get_curr_func_node(tid);
287 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
289 Predicate * selected_branch = get_selected_child_branch(tid);
290 ConcretePredicate * concrete = selected_branch->evaluate(inst_act_map, tid);
291 concrete->set_location(read->get_location());
293 history->add_waiting_write(concrete);
294 /* history->add_waiting_thread is already called in find_threads */
297 bool NewFuzzer::has_paused_threads()
299 return paused_thread_list.size() != 0;
302 Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
304 if (numthreads == 0 && has_paused_threads()) {
305 wake_up_paused_threads(threadlist, &numthreads);
306 //model_print("list size: %d, active t id: %d\n", numthreads, threadlist[0]);
309 int random_index = random() % numthreads;
310 int thread = threadlist[random_index];
311 thread_id_t curr_tid = int_to_id(thread);
312 return execution->get_thread(curr_tid);
315 /* Force waking up one of threads paused by Fuzzer, because otherwise
316 * the Fuzzer is not making progress
318 void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
320 int random_index = random() % paused_thread_list.size();
321 Thread * thread = paused_thread_list[random_index];
322 model->getScheduler()->remove_sleep(thread);
324 Thread * last_thread = paused_thread_list.back();
325 paused_thread_list[random_index] = last_thread;
326 paused_thread_list.pop_back();
327 paused_thread_table.put(last_thread, random_index); // Update table
328 paused_thread_table.remove(thread);
330 thread_id_t tid = thread->get_id();
331 history->remove_waiting_write(tid);
332 history->remove_waiting_thread(tid);
334 threadlist[*numthreads] = tid;
338 Predicate * selected_branch = get_selected_child_branch(tid);
339 update_predicate_score(selected_branch, SLEEP_FAIL_TYPE3);
342 model_print("thread %d is woken up\n", tid);
345 /* Wake up conditional sleeping threads if the desired write is available */
346 void NewFuzzer::notify_paused_thread(Thread * thread)
348 ASSERT(paused_thread_table.contains(thread));
350 int index = paused_thread_table.get(thread);
351 model->getScheduler()->remove_sleep(thread);
353 Thread * last_thread = paused_thread_list.back();
354 paused_thread_list[index] = last_thread;
355 paused_thread_list.pop_back();
356 paused_thread_table.put(last_thread, index); // Update table
357 paused_thread_table.remove(thread);
359 thread_id_t tid = thread->get_id();
360 history->remove_waiting_write(tid);
361 history->remove_waiting_thread(tid);
364 Predicate * selected_branch = get_selected_child_branch(tid);
365 update_predicate_score(selected_branch, SLEEP_SUCCESS);
368 model_print("** thread %d is woken up\n", tid);
371 /* Find threads that may write values that the pending read action is waiting for.
372 * Side effect: waiting thread related info are stored in dist_info_vec
374 * @return True if any thread is found
376 bool NewFuzzer::find_threads(ModelAction * pending_read)
378 ASSERT(pending_read->is_read());
380 void * location = pending_read->get_location();
381 thread_id_t self_id = pending_read->get_tid();
382 bool finds_waiting_for = false;
384 SnapVector<FuncNode *> * func_node_list = history->getWrFuncNodes(location);
385 for (uint i = 0;i < func_node_list->size();i++) {
386 FuncNode * target_node = (*func_node_list)[i];
387 for (uint i = 1;i < execution->get_num_threads();i++) {
388 thread_id_t tid = int_to_id(i);
392 FuncNode * node = history->get_curr_func_node(tid);
393 /* It is possible that thread tid is not in any FuncNode */
397 int distance = node->compute_distance(target_node);
398 if (distance != -1) {
399 finds_waiting_for = true;
400 //model_print("thread: %d; distance from node %d to node %d: %d\n", tid, node->get_func_id(), target_node->get_func_id(), distance);
402 dist_info_vec.push_back(node_dist_info(tid, target_node, distance));
407 return finds_waiting_for;
410 bool NewFuzzer::check_predicate_expressions(PredExprSet * pred_expressions,
411 inst_act_map_t * inst_act_map, uint64_t write_val, bool * no_predicate)
413 bool satisfy_predicate = true;
415 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
416 while (pred_expr_it->hasNext()) {
417 struct pred_expr * expression = pred_expr_it->next();
420 switch (expression->token) {
422 *no_predicate = true;
425 FuncInst * to_be_compared;
426 ModelAction * last_act;
429 to_be_compared = expression->func_inst;
430 last_act = inst_act_map->get(to_be_compared);
431 last_read = last_act->get_reads_from_value();
433 equality = (write_val == last_read);
434 if (equality != expression->value)
435 satisfy_predicate = false;
438 // TODO: implement likely to be null
439 equality = ((void*) (write_val & 0xffffffff) == NULL);
440 if (equality != expression->value)
441 satisfy_predicate = false;
444 model_print("unknown predicate token\n");
448 if (!satisfy_predicate)
453 return satisfy_predicate;
456 bool NewFuzzer::shouldWait(const ModelAction * act)