X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=model.cc;h=f12e4d27db44af7b3593067c806c539ce930ced9;hp=a7d9aeba173fef53b9375d157aa731f705a14e2a;hb=ad660ce6ce8b50abe7a380f643a5e22fb2b282df;hpb=1d6c949fef3b5da936f8499dde464f8df634267a diff --git a/model.cc b/model.cc index a7d9aeb..f12e4d2 100644 --- a/model.cc +++ b/model.cc @@ -2,132 +2,134 @@ #include "model.h" #include "action.h" -#include "tree.h" +#include "nodestack.h" #include "schedule.h" +#include "snapshot-interface.h" #include "common.h" +#include "clockvector.h" #define INITIAL_THREAD_ID 0 -class Backtrack { -public: - Backtrack(ModelAction *d, action_list_t *t) { - diverge = d; - actionTrace = t; - iter = actionTrace->begin(); - } - ModelAction * get_diverge() { return diverge; } - action_list_t * get_trace() { return actionTrace; } - void advance_state() { iter++; } - ModelAction * get_state() { - return iter == actionTrace->end() ? NULL : *iter; - } -private: - ModelAction *diverge; - action_list_t *actionTrace; - /* points to position in actionTrace as we replay */ - action_list_t::iterator iter; -}; - ModelChecker *model; -void free_action_list(action_list_t *list) -{ - action_list_t::iterator it; - for (it = list->begin(); it != list->end(); it++) - delete (*it); - delete list; -} - +/** @brief Constructor */ ModelChecker::ModelChecker() -{ - /* First thread created will have id INITIAL_THREAD_ID */ - this->next_thread_id = INITIAL_THREAD_ID; - used_sequence_numbers = 0; + : /* Initialize default scheduler */ - this->scheduler = new Scheduler(); - - num_executions = 0; - this->current_action = NULL; - this->exploring = NULL; - this->nextThread = THREAD_ID_T_NONE; - - rootNode = new TreeNode(); - currentNode = rootNode; - action_trace = new action_list_t(); + scheduler(new Scheduler()), + /* First thread created will have id INITIAL_THREAD_ID */ + next_thread_id(INITIAL_THREAD_ID), + used_sequence_numbers(0), + + num_executions(0), + current_action(NULL), + diverge(NULL), + 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, MyAlloc< std::pair< int, class Thread * > > >::iterator it; - for (it = thread_map.begin(); it != thread_map.end(); it++) + std::map::iterator it; + for (it = thread_map->begin(); it != thread_map->end(); it++) delete (*it).second; - thread_map.clear(); + delete thread_map; - free_action_list(action_trace); - - delete this->scheduler; - delete rootNode; + 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"); - std::map, MyAlloc< std::pair< int, class Thread * > > >::iterator it; - for (it = thread_map.begin(); it != thread_map.end(); it++) - delete (*it).second; - thread_map.clear(); - action_trace = new action_list_t(); - currentNode = rootNode; + node_stack->reset_execution(); current_action = NULL; next_thread_id = INITIAL_THREAD_ID; used_sequence_numbers = 0; - /* scheduler reset ? */ + nextThread = 0; + next_backtrack = NULL; + 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; if (nextThread == THREAD_ID_T_NONE) return NULL; - t = thread_map[id_to_int(nextThread)]; + t = (*thread_map)[id_to_int(nextThread)]; ASSERT(t != NULL); 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() { ModelAction *next; thread_id_t tid; - next = exploring->get_state(); + /* Have we completed exploring the preselected path? */ + if (diverge == NULL) + return THREAD_ID_T_NONE; + + /* Else, we are trying to replay an execution */ + next = node_stack->get_next()->get_action(); - if (next == exploring->get_diverge()) { - TreeNode *node = next->get_node(); + if (next == diverge) { + Node *node = next->get_node()->get_parent(); - /* Reached divergence point; discard our current 'exploring' */ - DEBUG("*** Discard 'Backtrack' object ***\n"); - tid = node->getNextBacktrack(); - delete exploring; - exploring = NULL; + /* Reached divergence point */ + DEBUG("*** Divergence point ***\n"); + tid = node->get_next_backtrack(); + diverge = NULL; } else { tid = next->get_tid(); } @@ -135,37 +137,28 @@ thread_id_t ModelChecker::get_next_replay_thread() return tid; } -thread_id_t ModelChecker::advance_backtracking_state() -{ - /* Have we completed exploring the preselected path? */ - if (exploring == NULL) - return THREAD_ID_T_NONE; - - /* Else, we are trying to replay an execution */ - exploring->advance_state(); - - ASSERT(exploring->get_state() != NULL); - - return get_next_replay_thread(); -} - +/** + * 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(); num_executions++; print_summary(); - if ((exploring = model->get_next_backtrack()) == NULL) + if ((diverge = model->get_next_backtrack()) == NULL) return false; if (DBG_ENABLED()) { printf("Next execution will diverge at:\n"); - exploring->get_diverge()->print(); - print_list(exploring->get_trace()); + diverge->print(); } model->reset_to_initial_state(); - nextThread = get_next_replay_thread(); return true; } @@ -187,7 +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; @@ -196,76 +189,165 @@ ModelAction * ModelChecker::get_last_conflict(ModelAction *act) void ModelChecker::set_backtracking(ModelAction *act) { ModelAction *prev; - TreeNode *node; + Node *node; Thread *t = get_thread(act->get_tid()); prev = get_last_conflict(act); if (prev == NULL) return; - node = prev->get_node(); + node = prev->get_node()->get_parent(); - while (t && !node->is_enabled(t)) + while (!node->is_enabled(t)) t = t->get_parent(); /* Check if this has been explored already */ - if (node->hasBeenExplored(t->get_id())) + if (node->has_been_explored(t->get_id())) return; + + /* Cache the latest backtracking point */ + if (!next_backtrack || *prev > *next_backtrack) + next_backtrack = prev; + /* If this is a new backtracking point, mark the tree */ - if (node->setBacktrack(t->get_id()) != 0) + if (!node->set_backtrack(t->get_id())) return; - DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n", prev->get_tid(), t->get_id()); if (DBG_ENABLED()) { prev->print(); act->print(); } - - Backtrack *back = new Backtrack(prev, action_trace); - backtrack_list.push_back(back); } -Backtrack * ModelChecker::get_next_backtrack() +ModelAction * ModelChecker::get_next_backtrack() { - Backtrack *next; - if (backtrack_list.empty()) - return NULL; - next = backtrack_list.back(); - backtrack_list.pop_back(); + ModelAction *next = next_backtrack; + next_backtrack = NULL; return next; } void ModelChecker::check_current_action(void) { - ModelAction *next = this->current_action; + Node *currnode; - if (!next) { + ModelAction *curr = this->current_action; + ModelAction *tmp; + current_action = NULL; + if (!curr) { DEBUG("trying to push NULL action...\n"); return; } - current_action = NULL; - nextThread = advance_backtracking_state(); - next->set_node(currentNode); - set_backtracking(next); - currentNode = currentNode->explore_child(next); - this->action_trace->push_back(next); + + 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()->get_parent(); + + if (!currnode->backtrack_empty()) + if (!next_backtrack || *curr > *next_backtrack) + next_backtrack = curr; + + set_backtracking(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", TreeNode::getTotalNodes()); + 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; +} + +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; } -void ModelChecker::print_list(action_list_t *list) +/** + * 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; @@ -278,9 +360,21 @@ 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; + (*thread_map)[id_to_int(t->get_id())] = t; scheduler->add_thread(t); return 0; }