+
+ if (curr->is_rmwc()||curr->is_rmw()) {
+ ModelAction *tmp=process_rmw(curr);
+ already_added = true;
+ delete curr;
+ curr=tmp;
+ } 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);
+ 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);
+ }
+ }
+
+ /* Assign 'creation' parent */
+ if (curr->get_type() == THREAD_CREATE) {
+ Thread *th = (Thread *)curr->get_location();
+ th->set_creation(curr);
+ }
+
+ /* Deal with new thread */
+ if (curr->get_type() == THREAD_START) {
+ check_promises(NULL, curr->get_cv());
+ }
+
+ /* Assign reads_from values */
+ Thread *th = get_thread(curr->get_tid());
+ uint64_t value = VALUE_NONE;
+ if (curr->is_read()) {
+ const ModelAction *reads_from = curr->get_node()->get_read_from();
+ if (reads_from!=NULL) {
+ value = reads_from->get_value();
+ /* Assign reads_from, perform release/acquire synchronization */
+ curr->read_from(reads_from);
+ r_modification_order(curr,reads_from);
+ } else {
+ /* Read from future value */
+ value = curr->get_node()->get_future_value();
+ curr->read_from(NULL);
+ Promise * valuepromise=new Promise(curr, value);
+ promises->push_back(valuepromise);
+ }
+ } else if (curr->is_write()) {
+ w_modification_order(curr);
+ resolve_promises(curr);
+ }
+
+ th->set_return_value(value);
+
+ /* Add action to list. */
+ if (!already_added)
+ add_action_to_lists(curr);
+
+ /* Is there a better interface for setting the next thread rather
+ than this field/convoluted approach? Perhaps like just returning
+ it or something? */
+
+ /* Do not split atomic actions. */
+ if (curr->is_rmwr()) {
+ nextThread = thread_current()->get_id();
+ } else {
+ nextThread = get_next_replay_thread();
+ }
+
+ Node *currnode = curr->get_node();
+ Node *parnode = currnode->get_parent();
+
+ if (!parnode->backtrack_empty()||!currnode->readsfrom_empty()||!currnode->futurevalues_empty()||!currnode->promises_empty())
+ if (!next_backtrack || *curr > *next_backtrack)
+ next_backtrack = curr;
+
+ set_backtracking(curr);
+}
+
+/** @returns whether the current trace is feasible. */
+bool ModelChecker::isfeasible() {
+ return !cyclegraph->checkForCycles() && !failed_promise;
+}
+
+/** Close out a RMWR by converting previous RMWR into a RMW or READ. */
+ModelAction * ModelChecker::process_rmw(ModelAction * act) {
+ int tid = id_to_int(act->get_tid());
+ ModelAction *lastread=get_last_action(tid);
+ lastread->process_rmw(act);
+ if (act->is_rmw())
+ cyclegraph->addRMWEdge(lastread, lastread->get_reads_from());
+ return lastread;
+}
+
+/**
+ * Updates the cyclegraph with the constraints imposed from the current read.
+ * @param curr The current action. Must be a read.
+ * @param rf The action that curr reads from. Must be a write.
+ */
+void ModelChecker::r_modification_order(ModelAction * curr, const ModelAction *rf) {
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->ensureptr(curr->get_location());
+ unsigned int i;
+ ASSERT(curr->is_read());
+
+ /* Iterate over all threads */
+ for (i = 0; i < thrd_lists->size(); i++) {
+ /* 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;
+
+ /* Include at most one act per-thread that "happens before" curr */
+ if (act->happens_before(curr)) {
+ if (act->is_read()) {
+ const ModelAction * prevreadfrom=act->get_reads_from();
+ if (rf!=prevreadfrom)
+ cyclegraph->addEdge(rf, prevreadfrom);
+ } else if (rf!=act) {
+ cyclegraph->addEdge(rf, act);
+ }
+ break;
+ }
+ }
+ }
+}
+
+/**
+ * Updates the cyclegraph with the constraints imposed from the current write.
+ * @param curr The current action. Must be a write.
+ */
+void ModelChecker::w_modification_order(ModelAction * curr) {
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->ensureptr(curr->get_location());
+ unsigned int i;
+ ASSERT(curr->is_write());
+
+ 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());
+ if (last_seq_cst!=NULL)
+ cyclegraph->addEdge(curr, last_seq_cst);
+ }
+
+ /* Iterate over all threads */
+ for (i = 0; i < thrd_lists->size(); i++) {
+ /* 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;
+
+ /* Include at most one act per-thread that "happens before" curr */
+ if (act->happens_before(curr)) {
+ if (act->is_read()) {
+ cyclegraph->addEdge(curr, act->get_reads_from());
+ } else
+ cyclegraph->addEdge(curr, act);
+ break;
+ } else {
+ if (act->is_read()&&!act->is_synchronizing(curr)&&!act->same_thread(curr)) {
+ /* We have an action that:
+ (1) did not happen before us
+ (2) is a read and we are a write
+ (3) cannot synchronize with us
+ (4) is in a different thread
+ =>
+ that read could potentially read from our write.
+ */
+
+ if (act->get_node()->add_future_value(curr->get_value())&&
+ (!next_backtrack || *act > * next_backtrack))
+ next_backtrack = act;
+ }
+ }
+ }
+ }
+}
+
+/**
+ * Performs various bookkeeping operations for the current ModelAction. For
+ * instance, adds action to the per-object, per-thread action vector and to the
+ * action trace list of all thread actions.
+ *
+ * @param act is the ModelAction to add.
+ */
+void ModelChecker::add_action_to_lists(ModelAction *act)
+{
+ int tid = id_to_int(act->get_tid());
+ action_trace->push_back(act);
+
+ obj_map->ensureptr(act->get_location())->push_back(act);
+
+ std::vector<action_list_t> *vec = obj_thrd_map->ensureptr(act->get_location());
+ if (tid >= (int)vec->size())
+ vec->resize(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;
+}
+
+ModelAction * ModelChecker::get_last_action(thread_id_t tid)
+{
+ int nthreads = get_num_threads();
+ if ((int)thrd_last_action->size() < nthreads)
+ thrd_last_action->resize(nthreads);
+ return (*thrd_last_action)[id_to_int(tid)];
+}
+
+/**
+ * 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
+ */
+ModelAction * ModelChecker::get_last_seq_cst(const void *location)
+{
+ action_list_t *list = obj_map->ensureptr(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())
+ return *rit;
+ return NULL;
+}
+
+ModelAction * ModelChecker::get_parent_action(thread_id_t tid)
+{
+ ModelAction *parent = get_last_action(tid);
+ if (!parent)
+ parent = get_thread(tid)->get_creation();
+ return parent;
+}
+
+/**
+ * Returns the clock vector for a given thread.
+ * @param tid The thread whose clock vector we want
+ * @return Desired clock vector
+ */
+ClockVector * ModelChecker::get_cv(thread_id_t tid) {
+ return get_parent_action(tid)->get_cv();
+}
+
+
+/** Resolve promises. */
+
+void ModelChecker::resolve_promises(ModelAction *write) {
+ for(unsigned int i=0;i<promises->size();i++) {
+ Promise * promise=(*promises)[i];
+ if (write->get_node()->get_promise(i)) {
+ ModelAction * read=promise->get_action();
+ read->read_from(write);
+ r_modification_order(read, write);
+ }
+ }