#include "history.h"
#include "funcnode.h"
#include "funcinst.h"
-#include "predicate.h"
#include "concretepredicate.h"
#include "waitobj.h"
NewFuzzer::NewFuzzer() :
thrd_last_read_act(),
- thrd_curr_pred(),
+ thrd_last_func_inst(),
thrd_selected_child_branch(),
thrd_pruned_writes(),
- paused_thread_set(),
- paused_thread_table(128)
+ paused_thread_list(),
+ paused_thread_table(128),
+ failed_predicates(32),
+ dist_info_vec()
{}
/**
thread_id_t tid = read->get_tid();
int thread_id = id_to_int(tid);
- if (thrd_last_read_act.size() <= (uint) thread_id)
+ if (thrd_last_read_act.size() <= (uint) thread_id) {
thrd_last_read_act.resize(thread_id + 1);
+ thrd_last_func_inst.resize(thread_id + 1);
+ }
// A new read action is encountered, select a random child branch of current predicate
if (read != thrd_last_read_act[thread_id]) {
- thrd_last_read_act[thread_id] = read;
-
FuncNode * func_node = history->get_curr_func_node(tid);
Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
FuncInst * read_inst = func_node->get_inst(read);
- Predicate * selected_branch = selectBranch(tid, curr_pred, read_inst);
-
inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
+
+ check_store_visibility(curr_pred, read_inst, inst_act_map, rf_set);
+ Predicate * selected_branch = selectBranch(tid, curr_pred, read_inst);
prune_writes(tid, selected_branch, rf_set, inst_act_map);
+
+ if (!failed_predicates.isEmpty())
+ failed_predicates.reset();
+
+ thrd_last_read_act[thread_id] = read;
+ thrd_last_func_inst[thread_id] = read_inst;
}
// No write satisfies the selected predicate, so pause this thread.
- if ( rf_set->size() == 0 ) {
+ while ( rf_set->size() == 0 ) {
+ Predicate * selected_branch = get_selected_child_branch(tid);
+
+ //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());
+
+/*--
Thread * read_thread = execution->get_thread(tid);
- 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());
+ bool should_reselect_predicate = true;
+ bool should_sleep = should_conditional_sleep(selected_branch);
+ dist_info_vec.clear();
+
+ if (!find_threads(read)) {
+ update_predicate_score(selected_branch, SLEEP_FAIL_TYPE1);
+ should_reselect_predicate = true;
+ } else if (!should_sleep) {
+ update_predicate_score(selected_branch, SLEEP_FAIL_TYPE2);
+ should_reselect_predicate = true;
+ } else {
+ for (uint i = 0; i < dist_info_vec.size(); i++) {
+ struct node_dist_info info = dist_info_vec[i];
+ history->add_waiting_thread(tid, info.tid, info.target, info.dist);
+ }
- // reset thread pending action and revert sequence numbers
- read_thread->set_pending(read);
- read->reset_seq_number();
- execution->restore_last_seq_num();
+ // reset thread pending action and revert sequence numbers
+ read_thread->set_pending(read);
+ read->reset_seq_number();
+ execution->restore_last_seq_num();
- conditional_sleep(read_thread);
+ conditional_sleep(read_thread);
+ // Returning -1 stops the while loop of ModelExecution::process_read
+ return -1;
+ }
+*/
- return -1;
-/*
SnapVector<ModelAction *> * pruned_writes = thrd_pruned_writes[thread_id];
- for (uint i = 0; i < pruned_writes->size(); i++)
+ for (uint i = 0; i < pruned_writes->size(); i++) {
rf_set->push_back( (*pruned_writes)[i] );
- pruned_writes->clear();
-*/
+ }
+
+ // Reselect a predicate and prune writes
+ Predicate * curr_pred = selected_branch->get_parent();
+ FuncInst * read_inst = thrd_last_func_inst[thread_id];
+ selected_branch = selectBranch(tid, curr_pred, read_inst);
+
+ FuncNode * func_node = history->get_curr_func_node(tid);
+ inst_act_map_t * inst_act_map = func_node->get_inst_act_map(tid);
+ prune_writes(tid, selected_branch, rf_set, inst_act_map);
+
+ ASSERT(selected_branch);
}
ASSERT(rf_set->size() != 0);
return random_index;
}
+void NewFuzzer::check_store_visibility(Predicate * curr_pred, FuncInst * read_inst,
+ inst_act_map_t * inst_act_map, SnapVector<ModelAction *> * rf_set)
+{
+ ASSERT(!rf_set->empty());
+ if (curr_pred == NULL || read_inst == NULL)
+ return;
+
+ ModelVector<Predicate *> * children = curr_pred->get_children();
+
+ /* Iterate over all predicate children */
+ for (uint i = 0; i < children->size(); i++) {
+ Predicate * branch = (*children)[i];
+
+ /* The children predicates may have different FuncInsts */
+ if (branch->get_func_inst() == read_inst) {
+ PredExprSet * pred_expressions = branch->get_pred_expressions();
+
+ /* Do not check unset predicates */
+ if (pred_expressions->isEmpty())
+ continue;
+
+ branch->incr_total_checking_count();
+
+ /* Iterate over all write actions */
+ for (uint j = 0; j < rf_set->size(); j++) {
+ ModelAction * write_act = (*rf_set)[j];
+ uint64_t write_val = write_act->get_write_value();
+ bool dummy = true;
+ bool satisfy_predicate = check_predicate_expressions(pred_expressions, inst_act_map, write_val, &dummy);
+
+ /* If one write value satisfies the predicate, go to check the next predicate */
+ if (satisfy_predicate) {
+ branch->incr_store_visible_count();
+ break;
+ }
+ }
+ }
+
+ }
+}
+
+
/* Select a random branch from the children of curr_pred
* @return The selected branch
*/
for (uint i = 0; i < children->size(); i++) {
Predicate * child = (*children)[i];
- if (child->get_func_inst() == read_inst)
+ if (child->get_func_inst() == read_inst && !failed_predicates.contains(child)) {
branches.push_back(child);
+
+ /*-- max of (exploration counts + 1)
+ if (child->get_expl_count() + 1 > numerator)
+ numerator = child->get_expl_count() + 1;
+ */
+ }
}
// predicate children have not been generated
return NULL;
}
- // randomly select a branch
- int random_index = random() % branches.size();
- Predicate * random_branch = branches[ random_index ];
+ int index = choose_index(&branches, 0);
+ Predicate * random_branch = branches[ index ];
thrd_selected_child_branch[thread_id] = random_branch;
+ // Update predicate tree position
+ FuncNode * func_node = history->get_curr_func_node(tid);
+ func_node->set_predicate_tree_position(tid, random_branch);
+
return random_branch;
}
+/**
+ * @brief Select a branch from the given predicate branches based
+ * on their exploration counts.
+ *
+ * Let b_1, ..., b_n be branches with exploration counts c_1, ..., c_n
+ * M := max(c_1, ..., c_n) + 1
+ * Factor f_i := M / (c_i + 1)
+ * The probability p_i that branch b_i is selected:
+ * p_i := f_i / (f_1 + ... + f_n)
+ * = \fraction{ 1/(c_i + 1) }{ 1/(c_1 + 1) + ... + 1/(c_n + 1) }
+ *
+ * Note: (1) c_i + 1 is used because counts may be 0.
+ * (2) The numerator of f_i is chosen to reduce the effect of underflow
+ *
+ * @param numerator is M defined above
+ */
+int NewFuzzer::choose_index(SnapVector<Predicate *> * branches, uint32_t numerator)
+{
+ return random() % branches->size();
+/*--
+ if (branches->size() == 1)
+ return 0;
+
+ double total_factor = 0;
+ SnapVector<double> factors = SnapVector<double>( branches->size() + 1 );
+ for (uint i = 0; i < branches->size(); i++) {
+ Predicate * branch = (*branches)[i];
+ double factor = (double) numerator / (branch->get_expl_count() + 5 * branch->get_fail_count() + 1);
+ total_factor += factor;
+ factors.push_back(factor);
+ }
+
+ double prob = (double) random() / RAND_MAX;
+ double prob_sum = 0;
+ int index = 0;
+
+ for (uint i = 0; i < factors.size(); i++) {
+ index = i;
+ prob_sum += (double) (factors[i] / total_factor);
+ if (prob_sum > prob) {
+ break;
+ }
+ }
+
+ return index;
+*/
+}
+
Predicate * NewFuzzer::get_selected_child_branch(thread_id_t tid)
{
int thread_id = id_to_int(tid);
bool pruned = false;
uint index = 0;
- ConcretePredicate * concrete_pred = pred->evaluate(inst_act_map, tid);
- SnapVector<struct concrete_pred_expr> * concrete_exprs = concrete_pred->getExpressions();
-
while ( index < rf_set->size() ) {
ModelAction * write_act = (*rf_set)[index];
uint64_t write_val = write_act->get_write_value();
- bool satisfy_predicate = true;
-
- for (uint i = 0; i < concrete_exprs->size(); i++) {
- struct concrete_pred_expr concrete = (*concrete_exprs)[i];
- bool equality;
-
- switch (concrete.token) {
- case NOPREDICATE:
- return false;
- case EQUALITY:
- equality = (write_val == concrete.value);
- if (equality != concrete.equality)
- satisfy_predicate = false;
- break;
- case NULLITY:
- equality = ((void*)write_val == NULL);
- if (equality != concrete.equality)
- satisfy_predicate = false;
- break;
- default:
- model_print("unknown predicate token\n");
- break;
- }
+ bool no_predicate = false;
+ bool satisfy_predicate = check_predicate_expressions(pred_expressions, inst_act_map, write_val, &no_predicate);
- if (!satisfy_predicate)
- break;
- }
+ if (no_predicate)
+ return false;
if (!satisfy_predicate) {
ASSERT(rf_set != NULL);
index++;
}
- delete concrete_pred;
-
return pruned;
}
*/
void NewFuzzer::conditional_sleep(Thread * thread)
{
- int index = paused_thread_set.size();
+ int index = paused_thread_list.size();
model->getScheduler()->add_sleep(thread);
- paused_thread_set.push_back(thread);
+ paused_thread_list.push_back(thread);
paused_thread_table.put(thread, index); // Update table
/* Add the waiting condition to ModelHistory */
concrete->set_location(read->get_location());
history->add_waiting_write(concrete);
+ /* history->add_waiting_thread is already called in find_threads */
+}
- /* history->add_waiting_thread is called in find_threads */
- find_threads(read);
+/**
+ * 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_set.size() != 0;
+ return paused_thread_list.size() != 0;
}
Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
int random_index = random() % numthreads;
int thread = threadlist[random_index];
thread_id_t curr_tid = int_to_id(thread);
- return model->get_thread(curr_tid);
+ return execution->get_thread(curr_tid);
}
/* Force waking up one of threads paused by Fuzzer, because otherwise
*/
void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
{
- int random_index = random() % paused_thread_set.size();
- Thread * thread = paused_thread_set[random_index];
+ 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_set.back();
- paused_thread_set[random_index] = last_thread;
- paused_thread_set.pop_back();
+ 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);
history->remove_waiting_write(tid);
history->remove_waiting_thread(tid);
- model_print("thread %d is woken up\n", 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 */
int index = paused_thread_table.get(thread);
model->getScheduler()->remove_sleep(thread);
- Thread * last_thread = paused_thread_set.back();
- paused_thread_set[index] = last_thread;
- paused_thread_set.pop_back();
+ 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 */
-void NewFuzzer::find_threads(ModelAction * pending_read)
+/* 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++) {
int distance = node->compute_distance(target_node);
if (distance != -1) {
- history->add_waiting_thread(self_id, tid, distance);
- model_print("thread: %d; distance from node %d to node %d: %d\n", tid, node->get_func_id(), target_node->get_func_id(), distance);
+ 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)
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