X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=nodestack.cc;h=1de51693eea6ecd606fe3fd616536fa152cfdc4f;hb=84e24d516d4e9dbd30f1fff7e9a185d1540d20eb;hp=87b3ee531fbe2d10a7b52f229f23e7ea90196e9d;hpb=8587e516d89ec5d8da43fc28b7d89fc4d65e343e;p=model-checker.git diff --git a/nodestack.cc b/nodestack.cc index 87b3ee5..1de5169 100644 --- a/nodestack.cc +++ b/nodestack.cc @@ -3,15 +3,32 @@ #include "common.h" #include "model.h" -/** @brief Node constructor */ -Node::Node(ModelAction *act, int nthreads) +/** + * @brief Node constructor + * + * Constructs a single Node for use in a NodeStack. Each Node is associated + * with exactly one ModelAction (exception: the first Node should be created + * as an empty stub, to represent the first thread "choice") and up to one + * parent. + * + * @param act The ModelAction to associate with this Node. May be NULL. + * @param par The parent Node in the NodeStack. May be NULL if there is no + * parent. + * @param nthreads The number of threads which exist at this point in the + * execution trace. + */ +Node::Node(ModelAction *act, Node *par, int nthreads) : action(act), + parent(par), num_threads(nthreads), explored_children(num_threads), backtrack(num_threads), numBacktracks(0), - may_read_from() + may_read_from(), + read_from_index(0) { + if (act) + act->set_node(this); } /** @brief Node desctructor */ @@ -30,6 +47,14 @@ void Node::print() printf("******** empty action ********\n"); } +/** @brief Prints info about may_read_from set */ +void Node::print_may_read_from() +{ + readfrom_set_t::iterator it; + for (it = may_read_from.begin(); it != may_read_from.end(); it++) + (*it)->print(); +} + /** * Checks if the Thread associated with this thread ID has been explored from * this Node already. @@ -49,18 +74,19 @@ bool Node::has_been_explored(thread_id_t tid) */ bool Node::backtrack_empty() { - return numBacktracks == 0; + return (numBacktracks == 0); +} + +bool Node::readsfrom_empty() { + return ((read_from_index+1)>=may_read_from.size()); } /** - * Explore a child Node using a given ModelAction. This updates both the - * Node-internal and the ModelAction data to associate the ModelAction with - * this Node. - * @param act is the ModelAction to explore + * Mark the appropriate backtracking infromation for exploring a thread choice. + * @param act The ModelAction to explore */ void Node::explore_child(ModelAction *act) { - act->set_node(this); explore(act->get_tid()); } @@ -88,8 +114,9 @@ thread_id_t Node::get_next_backtrack() for (i = 0; i < backtrack.size(); i++) if (backtrack[i] == true) break; - if (i >= backtrack.size()) - return THREAD_ID_T_NONE; + /* Backtrack set was empty? */ + ASSERT(i != backtrack.size()); + backtrack[i] = false; numBacktracks--; return int_to_id(i); @@ -104,9 +131,26 @@ bool Node::is_enabled(Thread *t) * Add an action to the may_read_from set. * @param act is the action to add */ -void Node::add_read_from(ModelAction *act) +void Node::add_read_from(const ModelAction *act) { - may_read_from.insert(act); + may_read_from.push_back(act); +} + +/** + * Gets the next 'may_read_from' action from this Node. Only valid for a node + * where this->action is a 'read'. + * @todo Perform reads_from backtracking/replay properly, so that this function + * may remove elements from may_read_from + * @return The first element in may_read_from + */ +const ModelAction * Node::get_read_from() { + ASSERT(read_from_indexhas_been_explored(act->get_tid())) { + if (it != node_list.end()) { iter++; return (*iter)->get_action(); } - /* Diverging from previous execution; clear out remainder of list */ - node_list_t::iterator it = iter; - it++; - clear_node_list(&node_list, it, node_list.end()); - /* Record action */ get_head()->explore_child(act); - node_list.push_back(new Node(act, model->get_num_threads())); + node_list.push_back(new Node(act, get_head(), model->get_num_threads())); total_nodes++; iter++; return NULL; } +/** + * Empties the stack of all trailing nodes after a given position and calls the + * destructor for each. This function is provided an offset which determines + * how many nodes (relative to the current replay state) to save before popping + * the stack. + * @param numAhead The number of nodes to skip forward before popping the stack. + */ +void NodeStack::pop_restofstack(int numAhead) +{ + /* Diverging from previous execution; clear out remainder of list */ + node_list_t::iterator it = iter; + while (numAhead--) + it++; + clear_node_list(&node_list, it, node_list.end()); +} + Node * NodeStack::get_head() { if (node_list.empty())