X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=nodestack.cc;h=431baafbdce9809a2cb49ebcea30837182c852cf;hb=5485feb8f53f4fe816b08d854fc3e82b00c33b0b;hp=c9878a339ec384febedaa95385e31cac478cc169;hpb=eb8e9f61a400856421465d95ac52d9cffed2a491;p=model-checker.git diff --git a/nodestack.cc b/nodestack.cc index c9878a3..431baaf 100644 --- a/nodestack.cc +++ b/nodestack.cc @@ -3,13 +3,34 @@ #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) + backtrack(num_threads), + numBacktracks(0), + may_read_from(), + read_from_index(0), + future_values(), + future_index(-1) { + if (act) + act->set_node(this); } /** @brief Node desctructor */ @@ -28,6 +49,96 @@ void Node::print() printf("******** empty action ********\n"); } +/** @brief Prints info about may_read_from set */ +void Node::print_may_read_from() +{ + for (unsigned int i = 0; i < may_read_from.size(); i++) + may_read_from[i]->print(); +} + +/** + * Sets a promise to explore meeting with the given node. + * @param i is the promise index. + */ +void Node::set_promise(unsigned int i) { + if (i >= promises.size()) + promises.resize(i + 1, PROMISE_IGNORE); + if (promises[i] == PROMISE_IGNORE) + promises[i] = PROMISE_UNFULFILLED; +} + +/** + * Looks up whether a given promise should be satisfied by this node. + * @param i The promise index. + * @return true if the promise should be satisfied by the given model action. + */ +bool Node::get_promise(unsigned int i) { + return (i < promises.size()) && (promises[i] == PROMISE_FULFILLED); +} + +/** + * Increments to the next combination of promises. + * @return true if we have a valid combination. + */ +bool Node::increment_promise() { + for (unsigned int i = 0; i < promises.size(); i++) { + if (promises[i] == PROMISE_UNFULFILLED) { + promises[i] = PROMISE_FULFILLED; + while (i > 0) { + i--; + if (promises[i] == PROMISE_FULFILLED) + promises[i] = PROMISE_UNFULFILLED; + } + return true; + } + } + return false; +} + +/** + * Returns whether the promise set is empty. + * @return true if we have explored all promise combinations. + */ +bool Node::promise_empty() { + for (unsigned int i = 0; i < promises.size();i++) + if (promises[i] == PROMISE_UNFULFILLED) + return false; + return true; +} + +/** + * Adds a value from a weakly ordered future write to backtrack to. + * @param value is the value to backtrack to. + */ +bool Node::add_future_value(uint64_t value, modelclock_t expiration) { + int suitableindex=-1; + for (unsigned int i = 0; i < future_values.size(); i++) { + if (future_values[i].value == value) { + if (future_values[i].expiration>=expiration) + return false; + if (future_index < i) { + suitableindex=i; + } + } + } + + if (suitableindex!=-1) { + future_values[suitableindex].expiration=expiration; + return true; + } + struct future_value newfv={value, expiration}; + future_values.push_back(newfv); + return true; +} + +/** + * Checks whether the future_values set for this node is empty. + * @return true if the future_values set is empty. + */ +bool Node::future_value_empty() { + return ((future_index + 1) >= future_values.size()); +} + /** * Checks if the Thread associated with this thread ID has been explored from * this Node already. @@ -47,22 +158,23 @@ bool Node::has_been_explored(thread_id_t tid) */ bool Node::backtrack_empty() { - unsigned int i; - for (i = 0; i < backtrack.size(); i++) - if (backtrack[i] == true) - return false; - return true; + return (numBacktracks == 0); } /** - * 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 + * Checks whether the readsfrom set for this node is empty. + * @return true if the readsfrom set is empty. + */ +bool Node::read_from_empty() { + return ((read_from_index+1) >= may_read_from.size()); +} + +/** + * Mark the appropriate backtracking information 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()); } @@ -79,19 +191,22 @@ bool Node::set_backtrack(thread_id_t id) if (backtrack[i]) return false; backtrack[i] = true; + numBacktracks++; return true; } thread_id_t Node::get_next_backtrack() { - /* TODO: find next backtrack */ + /** @todo Find next backtrack */ unsigned int i; 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); } @@ -100,15 +215,81 @@ bool Node::is_enabled(Thread *t) return id_to_int(t->get_id()) < num_threads; } +/** + * Add an action to the may_read_from set. + * @param act is the action to add + */ +void Node::add_read_from(const ModelAction *act) +{ + may_read_from.push_back(act); +} + +/** + * Gets the next 'future_value' value from this Node. Only valid for a node + * where this->action is a 'read'. + * @return The first element in future_values + */ +uint64_t Node::get_future_value() { + ASSERT(future_indexaction is a 'read'. + * @return The first element in may_read_from + */ +const ModelAction * Node::get_read_from() { + if (read_from_index < may_read_from.size()) + return may_read_from[read_from_index]; + else + return NULL; +} + +/** + * Increments the index into the readsfrom set to explore the next item. + * @return Returns false if we have explored all items. + */ +bool Node::increment_read_from() { + read_from_index++; + return (read_from_index < may_read_from.size()); +} + +/** + * Increments the index into the future_values set to explore the next item. + * @return Returns false if we have explored all values. + */ +bool Node::increment_future_value() { + future_index++; + return (future_index < future_values.size()); +} + void Node::explore(thread_id_t tid) { int i = id_to_int(tid); - backtrack[i] = false; + if (backtrack[i]) { + backtrack[i] = false; + numBacktracks--; + } explored_children[i] = true; } static void clear_node_list(node_list_t *list, node_list_t::iterator start, - node_list_t::iterator end) + node_list_t::iterator end) { node_list_t::iterator it; @@ -148,25 +329,39 @@ ModelAction * NodeStack::explore_action(ModelAction *act) DBG(); ASSERT(!node_list.empty()); + node_list_t::iterator it=iter; + it++; - if (get_head()->has_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 gives the number of Nodes (including this Node) to skip over + * before removing nodes. + */ +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())