obj_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 *>()),
+ futurevalues(new std::vector<struct PendingFutureValue>()),
lazy_sync_with_release(new HashTable<void *, std::list<ModelAction *>, uintptr_t, 4>()),
thrd_last_action(new std::vector<ModelAction *>(1)),
node_stack(new NodeStack()),
{
ModelAction *prev;
Node *node;
- Thread *t = get_thread(act->get_tid());
+ Thread *t = get_thread(act);
prev = get_last_conflict(act);
if (prev == NULL)
* @param second_part_of_rmw is boolean that is true is this is the second action of a rmw.
* @return True if processing this read updates the mo_graph.
*/
-
bool ModelChecker::process_read(ModelAction *curr, Thread * th, bool second_part_of_rmw) {
uint64_t value;
- bool updated=false;
- while(true) {
+ bool updated = false;
+ while (true) {
const ModelAction *reads_from = curr->get_node()->get_read_from();
if (reads_from != NULL) {
+ mo_graph->startChanges();
+
value = reads_from->get_value();
- /* Assign reads_from, perform release/acquire synchronization */
- curr->read_from(reads_from);
+ bool r_status = false;
+
if (!second_part_of_rmw) {
check_recency(curr,false);
+ r_status = r_modification_order(curr, reads_from);
}
- bool r_status=r_modification_order(curr,reads_from);
- if (!second_part_of_rmw&&!isfeasible()&&(curr->get_node()->increment_read_from()||!curr->get_node()->future_value_empty())) {
+ if (!second_part_of_rmw&&!isfeasible()&&(curr->get_node()->increment_read_from()||curr->get_node()->increment_future_value())) {
mo_graph->rollbackChanges();
- too_many_reads=false;
+ too_many_reads = false;
continue;
}
+ curr->read_from(reads_from);
mo_graph->commitChanges();
updated |= r_status;
- } else {
+ } else if (!second_part_of_rmw) {
/* Read from future value */
value = curr->get_node()->get_future_value();
+ modelclock_t expiration = curr->get_node()->get_future_value_expiration();
curr->read_from(NULL);
- Promise *valuepromise = new Promise(curr, value);
+ Promise *valuepromise = new Promise(curr, value, expiration);
promises->push_back(valuepromise);
}
th->set_return_value(value);
second_part_of_rmw = true;
delete curr;
curr = tmp;
+ compute_promises(curr);
} else {
ModelAction *tmp = node_stack->explore_action(curr);
if (tmp) {
}
/* Thread specific actions */
- switch(curr->get_type()) {
+ switch (curr->get_type()) {
case THREAD_CREATE: {
Thread *th = (Thread *)curr->get_location();
th->set_creation(curr);
break;
}
case THREAD_JOIN: {
- Thread *wait, *join;
- wait = get_thread(curr->get_tid());
- join = (Thread *)curr->get_location();
- if (!join->is_complete())
- scheduler->wait(wait, 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);
+ }
break;
}
case THREAD_FINISH: {
- Thread *th = get_thread(curr->get_tid());
+ Thread *th = get_thread(curr);
while (!th->wait_list_empty()) {
- Thread *wake = th->pop_wait_list();
+ ModelAction *act = th->pop_wait_list();
+ Thread *wake = get_thread(act);
scheduler->wake(wake);
}
th->complete();
break;
}
- Thread *th = get_thread(curr->get_tid());
-
bool updated = false;
+
if (curr->is_read()) {
- updated=process_read(curr, th, second_part_of_rmw);
+ updated = process_read(curr, get_thread(curr), second_part_of_rmw);
}
if (curr->is_write()) {
- bool updated_mod_order=w_modification_order(curr);
- bool updated_promises=resolve_promises(curr);
- updated=updated_mod_order|updated_promises;
+ bool updated_mod_order = w_modification_order(curr);
+ bool updated_promises = resolve_promises(curr);
+ updated = updated_mod_order || updated_promises;
+
+ 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) &&
+ (!priv->next_backtrack || *pfv.act > *priv->next_backtrack))
+ priv->next_backtrack = pfv.act;
+ }
+ futurevalues->resize(0);
+ }
mo_graph->commitChanges();
- th->set_return_value(VALUE_NONE);
+ get_thread(curr)->set_return_value(VALUE_NONE);
}
if (updated)
if (!second_part_of_rmw)
add_action_to_lists(curr);
+ check_curr_backtracking(curr);
+
+ set_backtracking(curr);
+
+ return get_next_thread(curr);
+}
+
+void ModelChecker::check_curr_backtracking(ModelAction * curr) {
Node *currnode = curr->get_node();
Node *parnode = currnode->get_parent();
if ((!parnode->backtrack_empty() ||
- !currnode->read_from_empty() ||
- !currnode->future_value_empty() ||
- !currnode->promise_empty())
- && (!priv->next_backtrack ||
- *curr > *priv->next_backtrack)) {
+ !currnode->read_from_empty() ||
+ !currnode->future_value_empty() ||
+ !currnode->promise_empty())
+ && (!priv->next_backtrack ||
+ *curr > *priv->next_backtrack)) {
priv->next_backtrack = curr;
}
+}
- set_backtracking(curr);
-
- return get_next_thread(curr);
+bool ModelChecker::promises_expired() {
+ for (unsigned int promise_index = 0; promise_index < promises->size(); promise_index++) {
+ Promise *promise = (*promises)[promise_index];
+ if (promise->get_expiration()<priv->used_sequence_numbers) {
+ return true;
+ }
+ }
+ return false;
}
/** @returns whether the current partial trace must be a prefix of a
/** @returns whether the current partial trace is feasible. */
bool ModelChecker::isfeasible() {
- return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads;
+ return !mo_graph->checkForRMWViolation() && isfeasibleotherthanRMW();
+}
+
+/** @returns whether the current partial trace is feasible other than
+ * multiple RMW reading from the same store. */
+bool ModelChecker::isfeasibleotherthanRMW() {
+ return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads && !promises_expired();
}
/** Returns whether the current completed trace is feasible. */
int tid = id_to_int(act->get_tid());
ModelAction *lastread = get_last_action(tid);
lastread->process_rmw(act);
- if (act->is_rmw())
+ if (act->is_rmw() && lastread->get_reads_from()!=NULL) {
mo_graph->addRMWEdge(lastread->get_reads_from(), lastread);
+ mo_graph->commitChanges();
+ }
return lastread;
}
action_list_t::reverse_iterator rit = list->rbegin();
/* Skip past curr */
- if (!already_added) {
+ if (already_added) {
for (; (*rit) != curr; rit++)
;
/* go past curr now */
rit++;
}
- action_list_t::reverse_iterator ritcopy=rit;
+ action_list_t::reverse_iterator ritcopy = rit;
//See if we have enough reads from the same value
- int count=0;
+ int count = 0;
for (; count < params.maxreads; rit++,count++) {
if (rit==list->rend())
return;
return;
}
- for (int i=0;i<curr->get_node()->get_read_from_size();i++) {
+ for (int i = 0; i<curr->get_node()->get_read_from_size(); i++) {
//Get write
- const ModelAction * write=curr->get_node()->get_read_from_at(i);
+ const ModelAction * write = curr->get_node()->get_read_from_at(i);
//Need a different write
if (write==curr->get_reads_from())
continue;
/* Test to see whether this is a feasible write to read from*/
+ mo_graph->startChanges();
r_modification_order(curr, write);
- bool feasiblereadfrom=isfeasible();
+ bool feasiblereadfrom = isfeasible();
mo_graph->rollbackChanges();
if (!feasiblereadfrom)
continue;
- rit=ritcopy;
+ rit = ritcopy;
- bool feasiblewrite=true;
+ bool feasiblewrite = true;
//new we need to see if this write works for everyone
- for (int loop=count;loop>0;loop--,rit++) {
+ for (int loop = count; loop>0; loop--,rit++) {
ModelAction *act=*rit;
- bool foundvalue=false;
- for(int j=0;j<act->get_node()->get_read_from_size();j++) {
+ 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) {
- foundvalue=true;
+ foundvalue = true;
break;
}
}
if (!foundvalue) {
- feasiblewrite=false;
+ feasiblewrite = false;
break;
}
}
/* Include at most one act per-thread that "happens before" curr */
if (act->happens_before(curr)) {
- if (act->is_read()) {
+ if (act->is_write()) {
+ if (rf != act && act != curr) {
+ mo_graph->addEdge(act, rf);
+ added = true;
+ }
+ } else {
const ModelAction *prevreadfrom = act->get_reads_from();
if (prevreadfrom != NULL && rf != prevreadfrom) {
mo_graph->addEdge(prevreadfrom, rf);
added = true;
}
- } else if (rf != act) {
- mo_graph->addEdge(act, rf);
- added = true;
}
+
break;
}
}
* The following edge should be handled elsewhere:
* readfrom(act) --mo--> act
*/
- if (act->is_write())
- mo_graph->addEdge(act, curr);
- else if (act->is_read() && act->get_reads_from() != NULL)
+ 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)
mo_graph->addEdge(act->get_reads_from(), curr);
added = true;
break;
=>
that read could potentially read from our write.
*/
- if (act->get_node()->add_future_value(curr->get_value()) &&
- (!priv->next_backtrack || *act > *priv->next_backtrack))
- priv->next_backtrack = act;
+ 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};
+ futurevalues->push_back(pfv);
+ }
+ }
}
}
}
return added;
}
+/** Arbitrary reads from the future are not allowed. Section 29.3
+ * part 9 places some constraints. This method checks one result of constraint
+ * constraint. Others require compiler support. */
+
+bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, const ModelAction *reader) {
+ if (!writer->is_rmw())
+ return true;
+
+ if (!reader->is_rmw())
+ return true;
+
+ for (const ModelAction *search = writer->get_reads_from(); search != NULL; search = search->get_reads_from()) {
+ if (search==reader)
+ return false;
+ if (search->get_tid() == reader->get_tid() &&
+ search->happens_before(reader))
+ break;
+ }
+
+ 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
bool ModelChecker::release_seq_head(const ModelAction *rf,
std::vector<const ModelAction *> *release_heads) const
{
- ASSERT(rf->is_write());
if (!rf) {
/* read from future: need to settle this later */
return false; /* incomplete */
}
+
+ ASSERT(rf->is_write());
+
if (rf->is_release())
release_heads->push_back(rf);
if (rf->is_rmw()) {
bool ModelChecker::resolve_promises(ModelAction *write)
{
bool resolved = false;
+
for (unsigned int i = 0, promise_index = 0; promise_index < promises->size(); i++) {
Promise *promise = (*promises)[promise_index];
if (write->get_node()->get_promise(i)) {
ModelAction *read = promise->get_action();
read->read_from(write);
+ if (read->is_rmw()) {
+ mo_graph->addRMWEdge(write, read);
+ }
r_modification_order(read, write);
post_r_modification_order(read, write);
promises->erase(promises->begin() + promise_index);
} else
promise_index++;
}
-
return resolved;
}
continue;
/* Don't consider more than one seq_cst write if we are a seq_cst read. */
- if (!act->is_seqcst() || !curr->is_seqcst() || act == last_seq_cst) {
+ if (!curr->is_seqcst()|| (!act->is_seqcst() && (last_seq_cst==NULL||!act->happens_before(last_seq_cst))) || act == last_seq_cst) {
DEBUG("Adding action to may_read_from:\n");
if (DBG_ENABLED()) {
act->print();
if (curr) {
if (curr->get_state() == THREAD_READY) {
ASSERT(priv->current_action);
+
priv->nextThread = check_current_action(priv->current_action);
priv->current_action = NULL;
if (!curr->is_blocked() && !curr->is_complete())
projects / model-checker.git / blobdiff