X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=nodestack.cc;h=3db80e8f6b4f8931ad3a238215c4294c86cd9708;hp=379fb3b1fc15f219cdd870b4976af0e394fd2263;hb=b8b39c87557325a384faa45d0cae56a6f71f52b1;hpb=810306cb85accaaace9a50f174264f105991230b

diff --git a/nodestack.cc b/nodestack.cc
index 379fb3b..3db80e8 100644
--- a/nodestack.cc
+++ b/nodestack.cc
@@ -1,29 +1,89 @@
+#include <string.h>
+
 #include "nodestack.h"
 #include "action.h"
 #include "common.h"
+#include "model.h"
+#include "threads.h"
 
-int Node::total_nodes = 0;
-
-Node::Node(ModelAction *act, Node *parent)
+/**
+ * @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, Node *prevfairness)
 	: action(act),
-	num_threads(parent ? parent->num_threads : 1),
+	parent(par),
+	num_threads(nthreads),
 	explored_children(num_threads),
-	backtrack(num_threads)
+	backtrack(num_threads),
+	fairness(num_threads),
+	numBacktracks(0),
+	enabled_array(NULL),
+	may_read_from(),
+	read_from_index(0),
+	future_values(),
+	future_index(-1),
+	relseq_break_writes(),
+	relseq_break_index(0)
 {
-	total_nodes++;
-	if (act && act->get_type() == THREAD_CREATE) {
-		num_threads++;
-		explored_children.resize(num_threads);
-		backtrack.resize(num_threads);
+	if (act) {
+		act->set_node(this);
+		int currtid=id_to_int(act->get_tid());
+		int prevtid=(prevfairness != NULL)?id_to_int(prevfairness->action->get_tid()):0;
+		
+		if ( model->params.fairwindow != 0 ) {
+			for(int i=0;i<nthreads;i++) {
+				ASSERT(i<((int)fairness.size()));
+				struct fairness_info * fi=& fairness[i];
+				struct fairness_info * prevfi=(par!=NULL)&&(i<par->get_num_threads())?&par->fairness[i]:NULL;
+				if (prevfi) {
+					*fi=*prevfi;
+				}
+				if (parent->enabled_array[i]==THREAD_ENABLED) {
+					fi->enabled_count++;
+				}
+				if (i==currtid) {
+					fi->turns++;
+					fi->priority = false;
+				}
+				//Do window processing
+				if (prevfairness != NULL) {
+					if (prevfairness -> parent->enabled_array[i] == THREAD_ENABLED)
+						fi->enabled_count--;
+					if (i==prevtid) {
+						fi->turns--;
+					}
+					//Need full window to start evaluating conditions
+					//If we meet the enabled count and have no turns, give us priority
+					if ((fi->enabled_count >= model->params.enabledcount) &&
+							(fi->turns == 0))
+						fi->priority = true;
+				}
+			}
+		}
 	}
 }
 
+/** @brief Node desctructor */
 Node::~Node()
 {
 	if (action)
 		delete action;
+	if (enabled_array)
+		model_free(enabled_array);
 }
 
+/** Prints debugging info for the ModelAction associated with this Node */
 void Node::print()
 {
 	if (action)
@@ -32,142 +92,421 @@ 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() {
+	DBG();
+
+	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 < ((int) 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) >= ((int)future_values.size()));
+}
+
+/**
+ * Checks if the Thread associated with this thread ID has been explored from
+ * this Node already.
+ * @param tid is the thread ID to check
+ * @return true if this thread choice has been explored already, false
+ * otherwise
+ */
 bool Node::has_been_explored(thread_id_t tid)
 {
 	int id = id_to_int(tid);
 	return explored_children[id];
 }
 
+/**
+ * Checks if the backtracking set is empty.
+ * @return true if the backtracking set is empty
+ */
 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);
+}
+
+/**
+ * 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());
 }
 
-void Node::explore_child(ModelAction *act)
+/**
+ * Mark the appropriate backtracking information for exploring a thread choice.
+ * @param act The ModelAction to explore
+ */
+void Node::explore_child(ModelAction *act, enabled_type_t * is_enabled)
 {
-	act->set_node(this);
+	if ( ! enabled_array )
+		enabled_array=(enabled_type_t *)model_malloc(sizeof(enabled_type_t)*num_threads);
+	if (is_enabled != NULL)
+		memcpy(enabled_array, is_enabled, sizeof(enabled_type_t)*num_threads);
+	else {
+		for(int i=0;i<num_threads;i++)
+			enabled_array[i]=THREAD_DISABLED;
+	}
+
 	explore(act->get_tid());
 }
 
+/**
+ * Records a backtracking reference for a thread choice within this Node.
+ * Provides feedback as to whether this thread choice is already set for
+ * backtracking.
+ * @return false if the thread was already set to be backtracked, true
+ * otherwise
+ */
 bool Node::set_backtrack(thread_id_t id)
 {
 	int i = id_to_int(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);
 }
 
 bool Node::is_enabled(Thread *t)
 {
-	return id_to_int(t->get_id()) < num_threads;
+	int thread_id=id_to_int(t->get_id());
+	return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
 }
 
-void Node::explore(thread_id_t tid)
+bool Node::is_enabled(thread_id_t tid)
 {
-	int i = id_to_int(tid);
-	backtrack[i] = false;
-	explored_children[i] = true;
+	int thread_id=id_to_int(tid);
+	return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
+}
+
+bool Node::has_priority(thread_id_t tid)
+{
+	return fairness[id_to_int(tid)].priority;
 }
 
-static void clear_node_list(node_list_t *list, node_list_t::iterator start,
-					       node_list_t::iterator end)
+/**
+ * Add an action to the may_read_from set.
+ * @param act is the action to add
+ */
+void Node::add_read_from(const ModelAction *act)
 {
-	node_list_t::iterator it;
+	may_read_from.push_back(act);
+}
 
-	for (it = start; it != end; it++)
-		delete (*it);
-	list->erase(start, end);
+/**
+ * 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_index<((int)future_values.size()));
+	return future_values[future_index].value;
 }
 
-NodeStack::NodeStack()
+modelclock_t Node::get_future_value_expiration() {
+	ASSERT(future_index<((int)future_values.size()));
+	return future_values[future_index].expiration;
+}
+
+
+int Node::get_read_from_size() {
+	return may_read_from.size();
+}
+
+const ModelAction * Node::get_read_from_at(int i) {
+	return may_read_from[i];
+}
+
+/**
+ * Gets the next 'may_read_from' action from this Node. Only valid for a node
+ * where this->action 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() {
+	DBG();
+	promises.clear();
+	if (read_from_index < may_read_from.size()) {
+		read_from_index++;
+		return read_from_index < may_read_from.size();
+	}
+	return false;
+}
+
+/**
+ * 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() {
+	DBG();
+	promises.clear();
+	if (future_index < ((int)future_values.size())) {
+		future_index++;
+		return (future_index < ((int)future_values.size()));
+	}
+	return false;
+}
+
+/**
+ * Add a write ModelAction to the set of writes that may break the release
+ * sequence. This is used during replay exploration of pending release
+ * sequences. This Node must correspond to a release sequence fixup action.
+ *
+ * @param write The write that may break the release sequence. NULL means we
+ * allow the release sequence to synchronize.
+ */
+void Node::add_relseq_break(const ModelAction *write)
+{
+	relseq_break_writes.push_back(write);
+}
+
+/**
+ * Get the write that may break the current pending release sequence,
+ * according to the replay / divergence pattern.
+ *
+ * @return A write that may break the release sequence. If NULL, that means
+ * the release sequence should not be broken.
+ */
+const ModelAction * Node::get_relseq_break()
 {
-	node_list.push_back(new Node());
-	iter = node_list.begin();
+	if (relseq_break_index < (int)relseq_break_writes.size())
+		return relseq_break_writes[relseq_break_index];
+	else
+		return NULL;
+}
+
+/**
+ * Increments the index into the relseq_break_writes set to explore the next
+ * item.
+ * @return Returns false if we have explored all values.
+ */
+bool Node::increment_relseq_break()
+{
+	DBG();
+	promises.clear();
+	if (relseq_break_index < ((int)relseq_break_writes.size())) {
+		relseq_break_index++;
+		return (relseq_break_index < ((int)relseq_break_writes.size()));
+	}
+	return false;
+}
+
+/**
+ * @return True if all writes that may break the release sequence have been
+ * explored
+ */
+bool Node::relseq_break_empty() {
+	return ((relseq_break_index + 1) >= ((int)relseq_break_writes.size()));
+}
+
+void Node::explore(thread_id_t tid)
+{
+	int i = id_to_int(tid);
+	if (backtrack[i]) {
+		backtrack[i] = false;
+		numBacktracks--;
+	}
+	explored_children[i] = true;
+}
+
+NodeStack::NodeStack() :
+	node_list(1, new Node()),
+	iter(0),
+	total_nodes(0)
+{
+	total_nodes++;
 }
 
 NodeStack::~NodeStack()
 {
-	clear_node_list(&node_list, node_list.begin(), node_list.end());
+	for (unsigned int i = 0; i < node_list.size(); i++)
+		delete node_list[i];
 }
 
 void NodeStack::print()
 {
-	node_list_t::iterator it;
 	printf("............................................\n");
 	printf("NodeStack printing node_list:\n");
-	for (it = node_list.begin(); it != node_list.end(); it++) {
+	for (unsigned int it = 0; it < node_list.size(); it++) {
 		if (it == this->iter)
 			printf("vvv following action is the current iterator vvv\n");
-		(*it)->print();
+		node_list[it]->print();
 	}
 	printf("............................................\n");
 }
 
-ModelAction * NodeStack::explore_action(ModelAction *act)
+/** Note: The is_enabled set contains what actions were enabled when
+ *  act was chosen. */
+
+ModelAction * NodeStack::explore_action(ModelAction *act, enabled_type_t * is_enabled)
 {
 	DBG();
 
 	ASSERT(!node_list.empty());
 
-	if (get_head()->has_been_explored(act->get_tid())) {
-		/* Discard duplicate ModelAction */
-		delete act;
-		iter++;
-	} else { /* 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, get_head()));
+	if ((iter+1) < node_list.size()) {
 		iter++;
+		return node_list[iter]->get_action();
 	}
-	return (*iter)->get_action();
+
+	/* Record action */
+	get_head()->explore_child(act, is_enabled);
+	Node *prevfairness = NULL;
+	if ( model->params.fairwindow != 0 && iter > model->params.fairwindow ) {
+		prevfairness = node_list[iter-model->params.fairwindow];
+	}
+	node_list.push_back(new Node(act, get_head(), model->get_num_threads(), prevfairness));
+	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 */
+	unsigned int it=iter+numAhead;
+	for(unsigned int i=it;i<node_list.size();i++)
+		delete node_list[i];
+	node_list.resize(it);
 }
 
 Node * NodeStack::get_head()
 {
 	if (node_list.empty())
 		return NULL;
-	return *iter;
+	return node_list[iter];
 }
 
 Node * NodeStack::get_next()
 {
-	node_list_t::iterator it = iter;
 	if (node_list.empty()) {
 		DEBUG("Empty\n");
 		return NULL;
 	}
-	it++;
-	if (it == node_list.end()) {
+	unsigned int it=iter+1;
+	if (it == node_list.size()) {
 		DEBUG("At end\n");
 		return NULL;
 	}
-	return *it;
+	return node_list[it];
 }
 
 void NodeStack::reset_execution()
 {
-	iter = node_list.begin();
+	iter = 0;
 }