#include <stdio.h>
#include <algorithm>
+#include <mutex>
#include "model.h"
#include "action.h"
#include "cyclegraph.h"
#include "promise.h"
#include "datarace.h"
-#include "mutex.h"
-#include "threads.h"
+#include "threads-model.h"
#define INITIAL_THREAD_ID 0
thread_map(new HashTable<int, Thread *, int>()),
obj_map(new HashTable<const void *, action_list_t, uintptr_t, 4>()),
lock_waiters_map(new HashTable<const void *, action_list_t, uintptr_t, 4>()),
+ condvar_waiters_map(new HashTable<const void *, action_list_t, uintptr_t, 4>()),
obj_thrd_map(new HashTable<void *, std::vector<action_list_t>, uintptr_t, 4 >()),
promises(new std::vector< Promise *, SnapshotAlloc<Promise *> >()),
futurevalues(new std::vector< struct PendingFutureValue, SnapshotAlloc<struct PendingFutureValue> >()),
delete obj_thrd_map;
delete obj_map;
delete lock_waiters_map;
+ delete condvar_waiters_map;
delete action_trace;
for (unsigned int i = 0; i < promises->size(); i++)
return ++priv->used_sequence_numbers;
}
+Node * ModelChecker::get_curr_node() {
+ return node_stack->get_head();
+}
+
/**
* @brief Choose the next thread to execute.
*
scheduler->update_sleep_set(prevnode);
/* Reached divergence point */
- if (nextnode->increment_promise()) {
+ if (nextnode->increment_misc()) {
+ /* The next node will try to satisfy a different misc_index values. */
+ tid = next->get_tid();
+ node_stack->pop_restofstack(2);
+ } else if (nextnode->increment_promise()) {
/* The next node will try to satisfy a different set of promises. */
tid = next->get_tid();
node_stack->pop_restofstack(2);
scheduler->add_sleep(thread_map->get(id_to_int(next->get_tid())));
tid = prevnode->get_next_backtrack();
/* Make sure the backtracked thread isn't sleeping. */
- scheduler->remove_sleep(thread_map->get(id_to_int(tid)));
node_stack->pop_restofstack(1);
if (diverge==earliest_diverge) {
earliest_diverge=prevnode->get_action();
for(unsigned int i=0;i<get_num_threads();i++) {
thread_id_t tid=int_to_id(i);
Thread *thr=get_thread(tid);
- if ( scheduler->get_enabled(thr) == THREAD_SLEEP_SET ) {
+ if ( scheduler->get_enabled(thr) == THREAD_SLEEP_SET &&
+ thr->get_pending() == NULL ) {
thr->set_state(THREAD_RUNNING);
scheduler->next_thread(thr);
Thread::swap(&system_context, thr);
+ priv->current_action->set_sleep_flag();
thr->set_pending(priv->current_action);
}
}
Thread *thr=get_thread(tid);
if ( scheduler->get_enabled(thr) == THREAD_SLEEP_SET ) {
ModelAction *pending_act=thr->get_pending();
- if (pending_act->could_synchronize_with(curr)) {
+ if ((!curr->is_rmwr())&&pending_act->could_synchronize_with(curr)) {
//Remove this thread from sleep set
scheduler->remove_sleep(thr);
}
DEBUG("Number of acquires waiting on pending release sequences: %zu\n",
pending_rel_seqs->size());
- if (isfinalfeasible() || DBG_ENABLED())
+
+ if (isfinalfeasible() || (params.bound != 0 && priv->used_sequence_numbers > params.bound ) || DBG_ENABLED() ) {
+ checkDataRaces();
print_summary();
+ }
if ((diverge = get_next_backtrack()) == NULL)
return false;
}
break;
}
+ case ATOMIC_WAIT: {
+ /* linear search: from most recent to oldest */
+ action_list_t *list = obj_map->get_safe_ptr(act->get_location());
+ action_list_t::reverse_iterator rit;
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *prev = *rit;
+ if (!act->same_thread(prev)&&prev->is_failed_trylock())
+ return prev;
+ if (!act->same_thread(prev)&&prev->is_notify())
+ return prev;
+ }
+ break;
+ }
+
+ case ATOMIC_NOTIFY_ALL:
+ case ATOMIC_NOTIFY_ONE: {
+ /* linear search: from most recent to oldest */
+ action_list_t *list = obj_map->get_safe_ptr(act->get_location());
+ action_list_t::reverse_iterator rit;
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *prev = *rit;
+ if (!act->same_thread(prev)&&prev->is_wait())
+ return prev;
+ }
+ break;
+ }
default:
break;
}
for(int i = low_tid; i < high_tid; i++) {
thread_id_t tid = int_to_id(i);
- if (!node->is_enabled(tid))
+ /* Make sure this thread can be enabled here. */
+ if (i >= node->get_num_threads())
+ break;
+
+ /* Don't backtrack into a point where the thread is disabled or sleeping. */
+ if (node->enabled_status(tid)!=THREAD_ENABLED)
continue;
/* Check if this has been explored already */
*/
bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw)
{
- uint64_t value;
+ uint64_t value = VALUE_NONE;
bool updated = false;
while (true) {
const ModelAction *reads_from = curr->get_node()->get_read_from();
* @return True if synchronization was updated; false otherwise
*/
bool ModelChecker::process_mutex(ModelAction *curr) {
- std::mutex *mutex = (std::mutex *)curr->get_location();
- struct std::mutex_state *state = mutex->get_state();
+ std::mutex *mutex=NULL;
+ struct std::mutex_state *state=NULL;
+
+ if (curr->is_trylock() || curr->is_lock() || curr->is_unlock()) {
+ mutex = (std::mutex *)curr->get_location();
+ state = mutex->get_state();
+ } else if(curr->is_wait()) {
+ mutex = (std::mutex *)curr->get_value();
+ state = mutex->get_state();
+ }
+
switch (curr->get_type()) {
case ATOMIC_TRYLOCK: {
bool success = !state->islocked;
waiters->clear();
break;
}
+ case ATOMIC_WAIT: {
+ //unlock the lock
+ state->islocked = false;
+ //wake up the other threads
+ action_list_t *waiters = lock_waiters_map->get_safe_ptr((void *) curr->get_value());
+ //activate all the waiting threads
+ for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) {
+ scheduler->wake(get_thread(*rit));
+ }
+ waiters->clear();
+ //check whether we should go to sleep or not...simulate spurious failures
+ if (curr->get_node()->get_misc()==0) {
+ condvar_waiters_map->get_safe_ptr(curr->get_location())->push_back(curr);
+ //disable us
+ scheduler->sleep(get_current_thread());
+ }
+ break;
+ }
+ case ATOMIC_NOTIFY_ALL: {
+ action_list_t *waiters = condvar_waiters_map->get_safe_ptr(curr->get_location());
+ //activate all the waiting threads
+ for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) {
+ scheduler->wake(get_thread(*rit));
+ }
+ waiters->clear();
+ break;
+ }
+ case ATOMIC_NOTIFY_ONE: {
+ action_list_t *waiters = condvar_waiters_map->get_safe_ptr(curr->get_location());
+ int wakeupthread=curr->get_node()->get_misc();
+ action_list_t::iterator it = waiters->begin();
+ advance(it, wakeupthread);
+ scheduler->wake(get_thread(*it));
+ waiters->erase(it);
+ break;
+ }
+
default:
ASSERT(0);
}
if (promises->size() == 0) {
for (unsigned int i = 0; i < futurevalues->size(); i++) {
struct PendingFutureValue pfv = (*futurevalues)[i];
- if (pfv.act->get_node()->add_future_value(pfv.value, pfv.expiration) &&
+ //Do more ambitious checks now that mo is more complete
+ if (mo_may_allow(pfv.writer, pfv.act)&&
+ pfv.act->get_node()->add_future_value(pfv.writer->get_value(), pfv.writer->get_seq_number()+params.maxfuturedelay) &&
(!priv->next_backtrack || *pfv.act > *priv->next_backtrack))
priv->next_backtrack = pfv.act;
}
break;
}
case THREAD_JOIN: {
- Thread *waiting, *blocking;
- waiting = get_thread(curr);
- blocking = (Thread *)curr->get_location();
- if (!blocking->is_complete()) {
- blocking->push_wait_list(curr);
- scheduler->sleep(waiting);
- } else {
- do_complete_join(curr);
- updated = true; /* trigger rel-seq checks */
- }
+ Thread *blocking = (Thread *)curr->get_location();
+ ModelAction *act = get_last_action(blocking->get_id());
+ curr->synchronize_with(act);
+ updated = true; /* trigger rel-seq checks */
break;
}
case THREAD_FINISH: {
Thread *th = get_thread(curr);
while (!th->wait_list_empty()) {
ModelAction *act = th->pop_wait_list();
- Thread *wake = get_thread(act);
- scheduler->wake(wake);
- do_complete_join(act);
- updated = true; /* trigger rel-seq checks */
+ scheduler->wake(get_thread(act));
}
th->complete();
updated = true; /* trigger rel-seq checks */
* initializing clock vectors, and computing the promises to fulfill.
*
* @param curr The current action, as passed from the user context; may be
- * freed/invalidated after the execution of this function
- * @return The current action, as processed by the ModelChecker. Is only the
- * same as the parameter @a curr if this is a newly-explored action.
+ * freed/invalidated after the execution of this function, with a different
+ * action "returned" its place (pass-by-reference)
+ * @return True if curr is a newly-explored action; false otherwise
*/
-ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
+bool ModelChecker::initialize_curr_action(ModelAction **curr)
{
ModelAction *newcurr;
- if (curr->is_rmwc() || curr->is_rmw()) {
- newcurr = process_rmw(curr);
- delete curr;
+ if ((*curr)->is_rmwc() || (*curr)->is_rmw()) {
+ newcurr = process_rmw(*curr);
+ delete *curr;
if (newcurr->is_rmw())
compute_promises(newcurr);
- return newcurr;
+
+ *curr = newcurr;
+ return false;
}
- curr->set_seq_number(get_next_seq_num());
+ (*curr)->set_seq_number(get_next_seq_num());
- newcurr = node_stack->explore_action(curr, scheduler->get_enabled());
+ newcurr = node_stack->explore_action(*curr, scheduler->get_enabled());
if (newcurr) {
/* First restore type and order in case of RMW operation */
- if (curr->is_rmwr())
- newcurr->copy_typeandorder(curr);
+ if ((*curr)->is_rmwr())
+ newcurr->copy_typeandorder(*curr);
- ASSERT(curr->get_location() == newcurr->get_location());
- newcurr->copy_from_new(curr);
+ ASSERT((*curr)->get_location() == newcurr->get_location());
+ newcurr->copy_from_new(*curr);
/* Discard duplicate ModelAction; use action from NodeStack */
- delete curr;
+ delete *curr;
/* Always compute new clock vector */
newcurr->create_cv(get_parent_action(newcurr->get_tid()));
+
+ *curr = newcurr;
+ return false; /* Action was explored previously */
} else {
- newcurr = curr;
+ newcurr = *curr;
/* Always compute new clock vector */
newcurr->create_cv(get_parent_action(newcurr->get_tid()));
compute_promises(newcurr);
else if (newcurr->is_relseq_fixup())
compute_relseq_breakwrites(newcurr);
+ else if (newcurr->is_wait())
+ newcurr->get_node()->set_misc_max(2);
+ else if (newcurr->is_notify_one()) {
+ newcurr->get_node()->set_misc_max(condvar_waiters_map->get_safe_ptr(newcurr->get_location())->size());
+ }
+ return true; /* This was a new ModelAction */
}
- return newcurr;
}
/**
- * This method checks whether a model action is enabled at the given point.
- * At this point, it checks whether a lock operation would be successful at this point.
- * If not, it puts the thread in a waiter list.
+ * @brief Check whether a model action is enabled.
+ *
+ * Checks whether a lock or join operation would be successful (i.e., is the
+ * lock already locked, or is the joined thread already complete). If not, put
+ * the action in a waiter list.
+ *
* @param curr is the ModelAction to check whether it is enabled.
* @return a bool that indicates whether the action is enabled.
*/
lock_waiters_map->get_safe_ptr(curr->get_location())->push_back(curr);
return false;
}
+ } else if (curr->get_type() == THREAD_JOIN) {
+ Thread *blocking = (Thread *)curr->get_location();
+ if (!blocking->is_complete()) {
+ blocking->push_wait_list(curr);
+ return false;
+ }
}
return true;
if (!check_action_enabled(curr)) {
/* Make the execution look like we chose to run this action
- * much later, when a lock is actually available to release */
+ * much later, when a lock/join can succeed */
get_current_thread()->set_pending(curr);
scheduler->sleep(get_current_thread());
return get_next_thread(NULL);
}
- wake_up_sleeping_actions(curr);
-
- ModelAction *newcurr = initialize_curr_action(curr);
+ bool newly_explored = initialize_curr_action(&curr);
+ wake_up_sleeping_actions(curr);
/* Add the action to lists before any other model-checking tasks */
if (!second_part_of_rmw)
- add_action_to_lists(newcurr);
+ add_action_to_lists(curr);
/* Build may_read_from set for newly-created actions */
- if (curr == newcurr && curr->is_read())
+ if (newly_explored && curr->is_read())
build_reads_from_past(curr);
- curr = newcurr;
/* Initialize work_queue with the "current action" work */
work_queue_t work_queue(1, CheckCurrWorkEntry(curr));
return get_next_thread(curr);
}
-/**
- * Complete a THREAD_JOIN operation, by synchronizing with the THREAD_FINISH
- * operation from the Thread it is joining with. Must be called after the
- * completion of the Thread in question.
- * @param join The THREAD_JOIN action
- */
-void ModelChecker::do_complete_join(ModelAction *join)
-{
- Thread *blocking = (Thread *)join->get_location();
- ModelAction *act = get_last_action(blocking->get_id());
- join->synchronize_with(act);
-}
-
void ModelChecker::check_curr_backtracking(ModelAction * curr) {
Node *currnode = curr->get_node();
Node *parnode = currnode->get_parent();
if ((!parnode->backtrack_empty() ||
+ !currnode->misc_empty() ||
!currnode->read_from_empty() ||
!currnode->future_value_empty() ||
!currnode->promise_empty() ||
/** @return whether the current partial trace must be a prefix of a
* feasible trace. */
bool ModelChecker::isfeasibleprefix() {
- return promises->size() == 0 && pending_rel_seqs->size() == 0;
+ return promises->size() == 0 && pending_rel_seqs->size() == 0 && isfeasible();
}
/** @return whether the current partial trace is feasible. */
ModelAction *act=*rit;
bool foundvalue = false;
for (int j = 0; j<act->get_node()->get_read_from_size(); j++) {
- if (act->get_node()->get_read_from_at(i)==write) {
+ if (act->get_node()->get_read_from_at(j)==write) {
foundvalue = true;
break;
}
(3) cannot synchronize with us
(4) is in a different thread
=>
- that read could potentially read from our write.
+ that read could potentially read from our write. Note that
+ these checks are overly conservative at this point, we'll
+ do more checks before actually removing the
+ pendingfuturevalue.
+
*/
if (thin_air_constraint_may_allow(curr, act)) {
if (isfeasible() ||
(curr->is_rmw() && act->is_rmw() && curr->get_reads_from() == act->get_reads_from() && isfeasibleotherthanRMW())) {
- struct PendingFutureValue pfv = {curr->get_value(),curr->get_seq_number()+params.maxfuturedelay,act};
+ struct PendingFutureValue pfv = {curr,act};
futurevalues->push_back(pfv);
}
}
return true;
}
+/**
+ * Arbitrary reads from the future are not allowed. Section 29.3 part 9 places
+ * some constraints. This method checks one the following constraint (others
+ * require compiler support):
+ *
+ * If X --hb-> Y --mo-> Z, then X should not read from Z.
+ */
+bool ModelChecker::mo_may_allow(const ModelAction *writer, const ModelAction *reader)
+{
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->get_safe_ptr(reader->get_location());
+ unsigned int i;
+ /* Iterate over all threads */
+ for (i = 0; i < thrd_lists->size(); i++) {
+ const ModelAction *write_after_read = NULL;
+
+ /* Iterate over actions in thread, starting from most recent */
+ action_list_t *list = &(*thrd_lists)[i];
+ action_list_t::reverse_iterator rit;
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *act = *rit;
+
+ if (!reader->happens_before(act))
+ break;
+ else if (act->is_write())
+ write_after_read = act;
+ else if (act->is_read()&&act->get_reads_from()!=NULL&&act!=reader) {
+ write_after_read = act->get_reads_from();
+ }
+ }
+
+ if (write_after_read && write_after_read!=writer && mo_graph->checkReachable(write_after_read, writer))
+ return false;
+ }
+ return true;
+}
+
/**
* Finds the head(s) of the release sequence(s) containing a given ModelAction.
* The ModelAction under consideration is expected to be taking part in
continue;
}
- /* Only writes can break release sequences */
- if (!act->is_write())
+ /* Only non-RMW writes can break release sequences */
+ if (!act->is_write() || act->is_rmw())
continue;
/* Check modification order */
if ((int)thrd_last_action->size() <= tid)
thrd_last_action->resize(get_num_threads());
(*thrd_last_action)[tid] = act;
+
+ if (act->is_wait()) {
+ void *mutex_loc=(void *) act->get_value();
+ obj_map->get_safe_ptr(mutex_loc)->push_back(act);
+
+ std::vector<action_list_t> *vec = obj_thrd_map->get_safe_ptr(mutex_loc);
+ if (tid >= (int)vec->size())
+ vec->resize(priv->next_thread_id);
+ (*vec)[tid].push_back(act);
+
+ if ((int)thrd_last_action->size() <= tid)
+ thrd_last_action->resize(get_num_threads());
+ (*thrd_last_action)[tid] = act;
+ }
}
/**
/* Find: max({i in dom(S) | isUnlock(t_i) && samevar(t_i, t)}) */
action_list_t::reverse_iterator rit;
for (rit = list->rbegin(); rit != list->rend(); rit++)
- if ((*rit)->is_unlock())
+ if ((*rit)->is_unlock() || (*rit)->is_wait())
return *rit;
return NULL;
}
bool ModelChecker::resolve_promises(ModelAction *write)
{
bool resolved = false;
- std::vector<thread_id_t> threads_to_check;
+ std::vector< thread_id_t, ModelAlloc<thread_id_t> > threads_to_check;
for (unsigned int i = 0, promise_index = 0; promise_index < promises->size(); i++) {
Promise *promise = (*promises)[promise_index];
act->is_read() &&
!act->could_synchronize_with(curr) &&
!act->same_thread(curr) &&
+ act->get_location() == curr->get_location() &&
promise->get_value() == curr->get_value()) {
- curr->get_node()->set_promise(i);
+ curr->get_node()->set_promise(i, act->is_rmw());
}
}
}
}
}
+void ModelChecker::check_promises_thread_disabled() {
+ for (unsigned int i = 0; i < promises->size(); i++) {
+ Promise *promise = (*promises)[i];
+ if (promise->check_promise()) {
+ failed_promise = true;
+ return;
+ }
+ }
+}
+
/** Checks promises in response to addition to modification order for threads.
* Definitions:
* pthread is the thread that performed the read that created the promise
//do we have a pwrite for the promise, if not, set it
if (promise->get_write() == NULL ) {
promise->set_write(write);
+ //The pwrite cannot happen before the promise
+ if (write->happens_before(act) && (write != act)) {
+ failed_promise = true;
+ return;
+ }
}
if (mo_graph->checkPromise(write, promise)) {
failed_promise = true;
if (promise->has_sync_thread(tid))
continue;
- if (mo_graph->checkReachable(promise->get_write(), write)) {
+ if (promise->get_write()&&mo_graph->checkReachable(promise->get_write(), write)) {
if (promise->increment_threads(tid)) {
failed_promise = true;
return;
act->print();
curr->print();
}
- curr->get_node()->add_read_from(act);
+
+ if (curr->get_sleep_flag() && ! curr->is_seqcst()) {
+ if (sleep_can_read_from(curr, act))
+ curr->get_node()->add_read_from(act);
+ } else
+ curr->get_node()->add_read_from(act);
}
/* Include at most one act per-thread that "happens before" curr */
if (!initialized) {
/** @todo Need a more informative way of reporting errors. */
printf("ERROR: may read from uninitialized atomic\n");
+ set_assert();
}
if (DBG_ENABLED() || !initialized) {
curr->get_node()->print_may_read_from();
printf("End printing may_read_from\n");
}
+}
- ASSERT(initialized);
+bool ModelChecker::sleep_can_read_from(ModelAction * curr, const ModelAction *write) {
+ while(true) {
+ Node *prevnode=write->get_node()->get_parent();
+
+ bool thread_sleep=prevnode->enabled_status(curr->get_tid())==THREAD_SLEEP_SET;
+ if (write->is_release()&&thread_sleep)
+ return true;
+ if (!write->is_rmw()) {
+ return false;
+ }
+ if (write->get_reads_from()==NULL)
+ return true;
+ write=write->get_reads_from();
+ }
}
static void print_list(action_list_t *list)
printf("---------------------------------------------------------------------\n");
printf("Trace:\n");
-
+ unsigned int hash=0;
+
for (it = list->begin(); it != list->end(); it++) {
(*it)->print();
+ hash=hash^(hash<<3)^((*it)->hash());
}
+ printf("HASH %u\n", hash);
printf("---------------------------------------------------------------------\n");
}
if (!isfeasible())
return false;
+ if (params.bound != 0) {
+ if (priv->used_sequence_numbers > params.bound) {
+ return false;
+ }
+ }
+
DEBUG("(%d, %d)\n", curr ? id_to_int(curr->get_id()) : -1,
next ? id_to_int(next->get_id()) : -1);
projects / model-checker.git / blobdiff