2 #include "threads-model.h"
8 #include "concretepredicate.h"
13 #include "execution.h"
15 NewFuzzer::NewFuzzer() :
17 thrd_last_func_inst(),
18 thrd_selected_child_branch(),
21 paused_thread_table(128),
26 * @brief Register the ModelHistory and ModelExecution engine
28 void NewFuzzer::register_engine(ModelHistory * history, ModelExecution *execution)
30 this->history = history;
31 this->execution = execution;
34 int NewFuzzer::selectWrite(ModelAction *read, SnapVector<ModelAction *> * rf_set)
36 // return random() % rf_set->size();
38 thread_id_t tid = read->get_tid();
39 int thread_id = id_to_int(tid);
41 if (thrd_last_read_act.size() <= (uint) thread_id) {
42 thrd_last_read_act.resize(thread_id + 1);
43 thrd_last_func_inst.resize(thread_id + 1);
46 // A new read action is encountered, select a random child branch of current predicate
47 if (read != thrd_last_read_act[thread_id]) {
48 FuncNode * func_node = history->get_curr_func_node(tid);
49 Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
50 FuncInst * read_inst = func_node->get_inst(read);
51 Predicate * selected_branch = selectBranch(tid, curr_pred, read_inst);
53 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
54 prune_writes(tid, selected_branch, rf_set, inst_act_map);
56 if (!failed_predicates.isEmpty())
57 failed_predicates.reset();
59 thrd_last_read_act[thread_id] = read;
60 thrd_last_func_inst[thread_id] = read_inst;
63 // No write satisfies the selected predicate, so pause this thread.
64 while ( rf_set->size() == 0 ) {
65 Thread * read_thread = execution->get_thread(tid);
66 //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());
68 if (find_threads(read)) {
69 // reset thread pending action and revert sequence numbers
70 read_thread->set_pending(read);
71 read->reset_seq_number();
72 execution->restore_last_seq_num();
74 conditional_sleep(read_thread);
76 // Returning -1 stops the while loop of ModelExecution::process_read
79 Predicate * selected_branch = get_selected_child_branch(tid);
80 failed_predicates.put(selected_branch, true);
82 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
83 for (uint i = 0; i < pruned_writes->size(); i++) {
84 rf_set->push_back( (*pruned_writes)[i] );
87 // Reselect a predicate and prune writes
88 Predicate * curr_pred = selected_branch->get_parent();
89 FuncInst * read_inst = thrd_last_func_inst[thread_id];
90 selected_branch = selectBranch(tid, curr_pred, read_inst);
92 FuncNode * func_node = history->get_curr_func_node(tid);
93 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
94 prune_writes(tid, selected_branch, rf_set, inst_act_map);
96 ASSERT(selected_branch);
100 ASSERT(rf_set->size() != 0);
101 int random_index = random() % rf_set->size();
106 /* Select a random branch from the children of curr_pred
107 * @return The selected branch
109 Predicate * NewFuzzer::selectBranch(thread_id_t tid, Predicate * curr_pred, FuncInst * read_inst)
111 int thread_id = id_to_int(tid);
112 if ( thrd_selected_child_branch.size() <= (uint) thread_id)
113 thrd_selected_child_branch.resize(thread_id + 1);
115 if (curr_pred == NULL || read_inst == NULL) {
116 thrd_selected_child_branch[thread_id] = NULL;
120 ModelVector<Predicate *> * children = curr_pred->get_children();
121 SnapVector<Predicate *> branches;
123 for (uint i = 0; i < children->size(); i++) {
124 Predicate * child = (*children)[i];
125 if (child->get_func_inst() == read_inst && !failed_predicates.contains(child)) {
126 branches.push_back(child);
130 // predicate children have not been generated
131 if (branches.size() == 0) {
132 thrd_selected_child_branch[thread_id] = NULL;
136 // randomly select a branch
137 int random_index = random() % branches.size();
138 Predicate * random_branch = branches[ random_index ];
139 thrd_selected_child_branch[thread_id] = random_branch;
141 return random_branch;
144 Predicate * NewFuzzer::get_selected_child_branch(thread_id_t tid)
146 int thread_id = id_to_int(tid);
147 if (thrd_selected_child_branch.size() <= (uint) thread_id)
150 return thrd_selected_child_branch[thread_id];
153 /* Remove writes from the rf_set that do not satisfie the selected predicate,
154 * and store them in thrd_pruned_writes
156 * @return true if rf_set is pruned
158 bool NewFuzzer::prune_writes(thread_id_t tid, Predicate * pred,
159 SnapVector<ModelAction *> * rf_set, inst_act_map_t * inst_act_map)
164 PredExprSet * pred_expressions = pred->get_pred_expressions();
165 if (pred_expressions->getSize() == 0) // unset predicates
168 int thread_id = id_to_int(tid);
169 uint old_size = thrd_pruned_writes.size();
170 if (thrd_pruned_writes.size() <= (uint) thread_id) {
171 uint new_size = thread_id + 1;
172 thrd_pruned_writes.resize(new_size);
173 for (uint i = old_size; i < new_size; i++)
174 thrd_pruned_writes[i] = new SnapVector<ModelAction *>();
176 SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
177 pruned_writes->clear(); // clear the old pruned_writes set
182 while ( index < rf_set->size() ) {
183 ModelAction * write_act = (*rf_set)[index];
184 uint64_t write_val = write_act->get_write_value();
185 bool satisfy_predicate = true;
187 PredExprSetIter * pred_expr_it = pred_expressions->iterator();
188 while (pred_expr_it->hasNext()) {
189 struct pred_expr * expression = pred_expr_it->next();
192 switch (expression->token) {
196 FuncInst * to_be_compared;
197 ModelAction * last_act;
200 to_be_compared = expression->func_inst;
201 last_act = inst_act_map->get(to_be_compared);
202 last_read = last_act->get_reads_from_value();
204 equality = (write_val == last_read);
205 if (equality != expression->value)
206 satisfy_predicate = false;
209 equality = ((void*)write_val == NULL);
210 if (equality != expression->value)
211 satisfy_predicate = false;
214 model_print("unknown predicate token\n");
218 if (!satisfy_predicate)
222 if (!satisfy_predicate) {
223 ASSERT(rf_set != NULL);
224 (*rf_set)[index] = rf_set->back();
226 pruned_writes->push_back(write_act);
235 /* @brief Put a thread to sleep because no writes in rf_set satisfies the selected predicate.
237 * @param thread A thread whose last action is a read
239 void NewFuzzer::conditional_sleep(Thread * thread)
241 int index = paused_thread_list.size();
243 model->getScheduler()->add_sleep(thread);
244 paused_thread_list.push_back(thread);
245 paused_thread_table.put(thread, index); // Update table
247 /* Add the waiting condition to ModelHistory */
248 ModelAction * read = thread->get_pending();
249 thread_id_t tid = thread->get_id();
250 FuncNode * func_node = history->get_curr_func_node(tid);
251 inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
253 Predicate * selected_branch = get_selected_child_branch(tid);
254 ConcretePredicate * concrete = selected_branch->evaluate(inst_act_map, tid);
255 concrete->set_location(read->get_location());
257 history->add_waiting_write(concrete);
258 /* history->add_waiting_thread is already called in find_threads */
261 bool NewFuzzer::has_paused_threads()
263 return paused_thread_list.size() != 0;
266 Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
268 if (numthreads == 0 && has_paused_threads()) {
269 wake_up_paused_threads(threadlist, &numthreads);
270 //model_print("list size: %d, active t id: %d\n", numthreads, threadlist[0]);
273 int random_index = random() % numthreads;
274 int thread = threadlist[random_index];
275 thread_id_t curr_tid = int_to_id(thread);
276 return execution->get_thread(curr_tid);
279 /* Force waking up one of threads paused by Fuzzer, because otherwise
280 * the Fuzzer is not making progress
282 void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
284 int random_index = random() % paused_thread_list.size();
285 Thread * thread = paused_thread_list[random_index];
286 model->getScheduler()->remove_sleep(thread);
288 Thread * last_thread = paused_thread_list.back();
289 paused_thread_list[random_index] = last_thread;
290 paused_thread_list.pop_back();
291 paused_thread_table.put(last_thread, random_index); // Update table
292 paused_thread_table.remove(thread);
294 thread_id_t tid = thread->get_id();
295 history->remove_waiting_write(tid);
296 history->remove_waiting_thread(tid);
298 //model_print("thread %d is woken up\n", tid);
299 threadlist[*numthreads] = tid;
303 /* Wake up conditional sleeping threads if the desired write is available */
304 void NewFuzzer::notify_paused_thread(Thread * thread)
306 ASSERT(paused_thread_table.contains(thread));
308 int index = paused_thread_table.get(thread);
309 model->getScheduler()->remove_sleep(thread);
311 Thread * last_thread = paused_thread_list.back();
312 paused_thread_list[index] = last_thread;
313 paused_thread_list.pop_back();
314 paused_thread_table.put(last_thread, index); // Update table
315 paused_thread_table.remove(thread);
317 thread_id_t tid = thread->get_id();
318 history->remove_waiting_write(tid);
319 history->remove_waiting_thread(tid);
322 /* Find threads that may write values that the pending read action is waiting for
323 * @return True if any thread is found
325 bool NewFuzzer::find_threads(ModelAction * pending_read)
327 ASSERT(pending_read->is_read());
329 void * location = pending_read->get_location();
330 thread_id_t self_id = pending_read->get_tid();
331 bool finds_waiting_for = false;
333 SnapVector<FuncNode *> * func_node_list = history->getWrFuncNodes(location);
334 for (uint i = 0; i < func_node_list->size(); i++) {
335 FuncNode * target_node = (*func_node_list)[i];
336 for (uint i = 1; i < execution->get_num_threads(); i++) {
337 thread_id_t tid = int_to_id(i);
341 FuncNode * node = history->get_curr_func_node(tid);
342 /* It is possible that thread tid is not in any FuncNode */
346 int distance = node->compute_distance(target_node);
347 if (distance != -1) {
348 history->add_waiting_thread(self_id, tid, target_node, distance);
349 finds_waiting_for = true;
350 //model_print("thread: %d; distance from node %d to node %d: %d\n", tid, node->get_func_id(), target_node->get_func_id(), distance);
355 return finds_waiting_for;
358 bool NewFuzzer::shouldWait(const ModelAction * act)