X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=model.cc;h=f12e4d27db44af7b3593067c806c539ce930ced9;hp=d28c1c26634ab2c772aab5881db6d78d49ffcaac;hb=ad660ce6ce8b50abe7a380f643a5e22fb2b282df;hpb=b7827b7c4bb29f0859b8623bccc34e5032cfd2aa diff --git a/model.cc b/model.cc index d28c1c2..f12e4d2 100644 --- a/model.cc +++ b/model.cc @@ -6,11 +6,13 @@ #include "schedule.h" #include "snapshot-interface.h" #include "common.h" +#include "clockvector.h" #define INITIAL_THREAD_ID 0 ModelChecker *model; +/** @brief Constructor */ ModelChecker::ModelChecker() : /* Initialize default scheduler */ @@ -25,11 +27,14 @@ ModelChecker::ModelChecker() nextThread(THREAD_ID_T_NONE), action_trace(new action_list_t()), thread_map(new std::map), + obj_thrd_map(new std::map >()), + thrd_last_action(new std::vector(1)), node_stack(new NodeStack()), next_backtrack(NULL) { } +/** @brief Destructor */ ModelChecker::~ModelChecker() { std::map::iterator it; @@ -37,12 +42,17 @@ ModelChecker::~ModelChecker() delete (*it).second; delete thread_map; + delete obj_thrd_map; delete action_trace; - + delete thrd_last_action; delete node_stack; delete scheduler; } +/** + * Restores user program to initial state and resets all model-checker data + * structures. + */ void ModelChecker::reset_to_initial_state() { DEBUG("+++ Resetting to initial state +++\n"); @@ -52,20 +62,36 @@ void ModelChecker::reset_to_initial_state() used_sequence_numbers = 0; nextThread = 0; next_backtrack = NULL; - /* scheduler reset ? */ snapshotObject->backTrackBeforeStep(0); } +/** @returns a thread ID for a new Thread */ thread_id_t ModelChecker::get_next_id() { return next_thread_id++; } +/** @returns the number of user threads created during this execution */ +int ModelChecker::get_num_threads() +{ + return next_thread_id; +} + +/** @returns a sequence number for a new ModelAction */ int ModelChecker::get_next_seq_num() { return ++used_sequence_numbers; } +/** + * Performs the "scheduling" for the model-checker. That is, it checks if the + * model-checker has selected a "next thread to run" and returns it, if + * available. This function should be called from the Scheduler routine, where + * the Scheduler falls back to a default scheduling routine if needed. + * + * @return The next thread chosen by the model-checker. If the model-checker + * makes no selection, retuns NULL. + */ Thread * ModelChecker::schedule_next_thread() { Thread *t; @@ -78,12 +104,12 @@ Thread * ModelChecker::schedule_next_thread() return t; } -/* - * get_next_replay_thread() - Choose the next thread in the replay sequence +/** + * Choose the next thread in the replay sequence. * - * If we've reached the 'diverge' point, then we pick a thread from the - * backtracking set. - * Otherwise, we simply return the next thread in the sequence. + * If the replay sequence has reached the 'diverge' point, returns a thread + * from the backtracking set. Otherwise, simply returns the next thread in the + * sequence that is being replayed. */ thread_id_t ModelChecker::get_next_replay_thread() { @@ -98,7 +124,7 @@ thread_id_t ModelChecker::get_next_replay_thread() next = node_stack->get_next()->get_action(); if (next == diverge) { - Node *node = next->get_node(); + Node *node = next->get_node()->get_parent(); /* Reached divergence point */ DEBUG("*** Divergence point ***\n"); @@ -111,6 +137,13 @@ thread_id_t ModelChecker::get_next_replay_thread() return tid; } +/** + * Queries the model-checker for more executions to explore and, if one + * exists, resets the model-checker state to execute a new execution. + * + * @return If there are more executions to explore, return true. Otherwise, + * return false. + */ bool ModelChecker::next_execution() { DBG(); @@ -147,7 +180,7 @@ ModelAction * ModelChecker::get_last_conflict(ModelAction *act) action_list_t::reverse_iterator rit; for (rit = action_trace->rbegin(); rit != action_trace->rend(); rit++) { ModelAction *prev = *rit; - if (act->is_dependent(prev)) + if (act->is_synchronizing(prev)) return prev; } return NULL; @@ -163,7 +196,7 @@ void ModelChecker::set_backtracking(ModelAction *act) if (prev == NULL) return; - node = prev->get_node(); + node = prev->get_node()->get_parent(); while (!node->is_enabled(t)) t = t->get_parent(); @@ -172,6 +205,7 @@ void ModelChecker::set_backtracking(ModelAction *act) if (node->has_been_explored(t->get_id())) return; + /* Cache the latest backtracking point */ if (!next_backtrack || *prev > *next_backtrack) next_backtrack = prev; @@ -198,38 +232,122 @@ void ModelChecker::check_current_action(void) Node *currnode; ModelAction *curr = this->current_action; + ModelAction *tmp; current_action = NULL; if (!curr) { DEBUG("trying to push NULL action...\n"); return; } - curr = node_stack->explore_action(curr); + tmp = node_stack->explore_action(curr); + if (tmp) { + /* Discard duplicate ModelAction; use action from NodeStack */ + 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); + } + + /* Assign 'creation' parent */ + if (curr->get_type() == THREAD_CREATE) { + Thread *th = (Thread *)curr->get_location(); + th->set_creation(curr); + } + nextThread = get_next_replay_thread(); - currnode = curr->get_node(); + currnode = curr->get_node()->get_parent(); if (!currnode->backtrack_empty()) if (!next_backtrack || *curr > *next_backtrack) next_backtrack = curr; set_backtracking(curr); - this->action_trace->push_back(curr); + + add_action_to_lists(curr); } -void ModelChecker::print_summary(void) +/** + * 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) { - printf("\n"); - printf("Number of executions: %d\n", num_executions); - printf("Total nodes created: %d\n", Node::get_total_nodes()); + action_trace->push_back(act); - scheduler->print(); + std::vector *vec = &(*obj_thrd_map)[act->get_location()]; + if (id_to_int(act->get_tid()) >= (int)vec->size()) + vec->resize(next_thread_id); + (*vec)[id_to_int(act->get_tid())].push_back(act); - print_list(action_trace); - printf("\n"); + (*thrd_last_action)[id_to_int(act->get_tid())] = act; } -void ModelChecker::print_list(action_list_t *list) +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)]; +} + +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; +} + +/** + * Build up an initial set of all past writes that this 'read' action may read + * from. This set is determined by the clock vector's "happens before" + * relationship. + * @param curr is the current ModelAction that we are exploring; it must be a + * 'read' operation. + */ +void ModelChecker::build_reads_from_past(ModelAction *curr) +{ + std::vector *thrd_lists = &(*obj_thrd_map)[curr->get_location()]; + unsigned int i; + + ASSERT(curr->is_read()); + + for (i = 0; i < thrd_lists->size(); i++) { + action_list_t *list = &(*thrd_lists)[i]; + action_list_t::reverse_iterator rit; + for (rit = list->rbegin(); rit != list->rend(); rit++) { + ModelAction *act = *rit; + + /* Only consider 'write' actions */ + if (!act->is_write()) + continue; + + DEBUG("Adding action to may_read_from:\n"); + if (DBG_ENABLED()) { + act->print(); + curr->print(); + } + curr->get_node()->add_read_from(act); + + /* Include at most one act that "happens before" curr */ + if (act->happens_before(curr)) + break; + } + } +} + +static void print_list(action_list_t *list) { action_list_t::iterator it; @@ -242,6 +360,18 @@ void ModelChecker::print_list(action_list_t *list) printf("---------------------------------------------------------------------\n"); } +void ModelChecker::print_summary(void) +{ + printf("\n"); + printf("Number of executions: %d\n", num_executions); + printf("Total nodes created: %d\n", node_stack->get_total_nodes()); + + scheduler->print(); + + print_list(action_trace); + printf("\n"); +} + int ModelChecker::add_thread(Thread *t) { (*thread_map)[id_to_int(t->get_id())] = t;