bool r_status = false;
if (!second_part_of_rmw) {
- check_recency(curr,false);
+ check_recency(curr);
r_status = r_modification_order(curr, reads_from);
}
return updated_mod_order || updated_promises;
}
+/**
+ * Initialize the current action by performing one or more of the following
+ * actions, as appropriate: merging RMWR and RMWC/RMW actions, stepping forward
+ * in the NodeStack, manipulating backtracking sets, allocating and
+ * 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.
+ */
+ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
+{
+ ModelAction *newcurr;
+
+ if (curr->is_rmwc() || curr->is_rmw()) {
+ newcurr = process_rmw(curr);
+ delete curr;
+ compute_promises(newcurr);
+ return newcurr;
+ }
+
+ newcurr = node_stack->explore_action(curr);
+ if (newcurr) {
+ /* First restore type and order in case of RMW operation */
+ if (curr->is_rmwr())
+ newcurr->copy_typeandorder(curr);
+
+ /* Discard duplicate ModelAction; use action from NodeStack */
+ delete curr;
+
+ /* If we have diverged, we need to reset the clock vector. */
+ if (diverge == NULL)
+ newcurr->create_cv(get_parent_action(newcurr->get_tid()));
+ } else {
+ newcurr = curr;
+ /*
+ * Perform one-time actions when pushing new ModelAction onto
+ * NodeStack
+ */
+ curr->create_cv(get_parent_action(curr->get_tid()));
+ if (curr->is_write())
+ compute_promises(curr);
+ }
+ return newcurr;
+}
+
/**
* This is the heart of the model checker routine. It performs model-checking
* actions corresponding to a given "current action." Among other processes, it
*/
Thread * ModelChecker::check_current_action(ModelAction *curr)
{
- bool second_part_of_rmw = false;
-
ASSERT(curr);
- if (curr->is_rmwc() || curr->is_rmw()) {
- ModelAction *tmp = process_rmw(curr);
- second_part_of_rmw = true;
- delete curr;
- curr = tmp;
- compute_promises(curr);
- } else {
- ModelAction *tmp = node_stack->explore_action(curr);
- if (tmp) {
- /* Discard duplicate ModelAction; use action from NodeStack */
- /* First restore type and order in case of RMW operation */
- if (curr->is_rmwr())
- tmp->copy_typeandorder(curr);
-
- /* If we have diverged, we need to reset the clock vector. */
- if (diverge == NULL)
- tmp->create_cv(get_parent_action(tmp->get_tid()));
-
- delete curr;
- curr = tmp;
- } else {
- /*
- * Perform one-time actions when pushing new ModelAction onto
- * NodeStack
- */
- curr->create_cv(get_parent_action(curr->get_tid()));
- /* Build may_read_from set */
- if (curr->is_read())
- build_reads_from_past(curr);
- if (curr->is_write())
- compute_promises(curr);
- }
- }
+ bool second_part_of_rmw = curr->is_rmwc() || curr->is_rmw();
+
+ ModelAction *newcurr = initialize_curr_action(curr);
+
+ /* Add the action to lists before any other model-checking tasks */
+ if (!second_part_of_rmw)
+ add_action_to_lists(newcurr);
+
+ /* Build may_read_from set for newly-created actions */
+ if (curr == newcurr && curr->is_read())
+ build_reads_from_past(curr);
+ curr = newcurr;
/* Thread specific actions */
switch (curr->get_type()) {
if (!blocking->is_complete()) {
blocking->push_wait_list(curr);
scheduler->sleep(waiting);
+ } else {
+ do_complete_join(curr);
}
break;
}
ModelAction *act = th->pop_wait_list();
Thread *wake = get_thread(act);
scheduler->wake(wake);
+ do_complete_join(act);
}
th->complete();
break;
break;
}
- /* Add current action to lists before work_queue loop */
- if (!second_part_of_rmw)
- add_action_to_lists(curr);
-
work_queue_t work_queue(1, CheckCurrWorkEntry(curr));
while (!work_queue.empty()) {
case WORK_CHECK_RELEASE_SEQ:
resolve_release_sequences(work.location, &work_queue);
break;
- case WORK_CHECK_MO_EDGES:
- /** @todo Perform follow-up mo_graph checks */
+ case WORK_CHECK_MO_EDGES: {
+ /** @todo Complete verification of work_queue */
+ ModelAction *act = work.action;
+ bool updated = false;
+
+ if (act->is_read()) {
+ if (r_modification_order(act, act->get_reads_from()))
+ updated = true;
+ }
+ if (act->is_write()) {
+ if (w_modification_order(act))
+ updated = true;
+ }
+
+ if (updated)
+ work_queue.push_back(CheckRelSeqWorkEntry(act->get_location()));
+ break;
+ }
default:
ASSERT(false);
break;
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();
/** @returns whether the current partial trace is feasible other than
* multiple RMW reading from the same store. */
bool ModelChecker::isfeasibleotherthanRMW() {
+ if (DBG_ENABLED()) {
+ if (mo_graph->checkForCycles())
+ DEBUG("Infeasible: modification order cycles\n");
+ if (failed_promise)
+ DEBUG("Infeasible: failed promise\n");
+ if (too_many_reads)
+ DEBUG("Infeasible: too many reads\n");
+ if (promises_expired())
+ DEBUG("Infeasible: promises expired\n");
+ }
return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads && !promises_expired();
}
/** Returns whether the current completed trace is feasible. */
bool ModelChecker::isfinalfeasible() {
+ if (DBG_ENABLED() && promises->size() != 0)
+ DEBUG("Infeasible: unrevolved promises\n");
+
return isfeasible() && promises->size() == 0;
}
*
* If so, we decide that the execution is no longer feasible.
*/
-void ModelChecker::check_recency(ModelAction *curr, bool already_added) {
+void ModelChecker::check_recency(ModelAction *curr) {
if (params.maxreads != 0) {
if (curr->get_node()->get_read_from_size() <= 1)
return;
action_list_t::reverse_iterator rit = list->rbegin();
/* Skip past curr */
- if (already_added) {
- for (; (*rit) != curr; rit++)
- ;
- /* go past curr now */
- rit++;
- }
+ for (; (*rit) != curr; rit++)
+ ;
+ /* go past curr now */
+ rit++;
action_list_t::reverse_iterator ritcopy = rit;
//See if we have enough reads from the same value
*/
if (act->happens_before(curr) && act != curr) {
if (act->is_write()) {
- if (rf != act && act != curr) {
+ if (rf != act) {
mo_graph->addEdge(act, rf);
added = true;
}
added = true;
}
}
-
break;
}
}
if (curr->is_seqcst()) {
/* We have to at least see the last sequentially consistent write,
so we are initialized. */
- ModelAction *last_seq_cst = get_last_seq_cst(curr->get_location());
+ ModelAction *last_seq_cst = get_last_seq_cst(curr);
if (last_seq_cst != NULL) {
mo_graph->addEdge(last_seq_cst, curr);
added = true;
action_list_t::reverse_iterator rit;
for (rit = list->rbegin(); rit != list->rend(); rit++) {
ModelAction *act = *rit;
+ if (act == curr) {
+ /*
+ * If RMW, we already have all relevant edges,
+ * so just skip to next thread.
+ * If normal write, we need to look at earlier
+ * actions, so continue processing list.
+ */
+ if (curr->is_rmw())
+ break;
+ else
+ continue;
+ }
/*
* Include at most one act per-thread that "happens
- * before" curr. Only consider reflexively if curr is
- * RMW.
+ * before" curr
*/
- if (act->happens_before(curr) && (act != curr || curr->is_rmw())) {
+ if (act->happens_before(curr)) {
/*
* Note: if act is RMW, just add edge:
* act --mo--> curr
* The following edge should be handled elsewhere:
* readfrom(act) --mo--> act
*/
- if (act->is_write()) {
- //RMW shouldn't have an edge to themselves
- if (act!=curr)
- mo_graph->addEdge(act, curr);
- } else if (act->is_read() && act->get_reads_from() != NULL)
+ if (act->is_write())
+ mo_graph->addEdge(act, curr);
+ else if (act->is_read() && act->get_reads_from() != NULL)
mo_graph->addEdge(act->get_reads_from(), curr);
added = true;
break;
}
/**
- * Gets the last memory_order_seq_cst action (in the total global sequence)
- * performed on a particular object (i.e., memory location).
- * @param location The object location to check
- * @return The last seq_cst action performed
+ * Gets the last memory_order_seq_cst write (in the total global sequence)
+ * performed on a particular object (i.e., memory location), not including the
+ * current action.
+ * @param curr The current ModelAction; also denotes the object location to
+ * check
+ * @return The last seq_cst write
*/
-ModelAction * ModelChecker::get_last_seq_cst(const void *location)
+ModelAction * ModelChecker::get_last_seq_cst(ModelAction *curr)
{
+ void *location = curr->get_location();
action_list_t *list = obj_map->get_safe_ptr(location);
/* Find: max({i in dom(S) | seq_cst(t_i) && isWrite(t_i) && samevar(t_i, t)}) */
action_list_t::reverse_iterator rit;
for (rit = list->rbegin(); rit != list->rend(); rit++)
- if ((*rit)->is_write() && (*rit)->is_seqcst())
+ if ((*rit)->is_write() && (*rit)->is_seqcst() && (*rit) != curr)
return *rit;
return NULL;
}
bool initialized = false;
if (curr->is_seqcst()) {
- last_seq_cst = get_last_seq_cst(curr->get_location());
+ last_seq_cst = get_last_seq_cst(curr);
/* We have to at least see the last sequentially consistent write,
so we are initialized. */
if (last_seq_cst != NULL)
ModelAction *act = *rit;
/* Only consider 'write' actions */
- if (!act->is_write())
+ if (!act->is_write() || act == curr)
continue;
/* Don't consider more than one seq_cst write if we are a seq_cst read. */
projects / model-checker.git / blobdiff