#include "nodestack.h"
#include "action.h"
#include "common.h"
+#include "model.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)
: action(act),
- num_threads(parent ? parent->num_threads : 1),
+ 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)
{
- 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);
}
+/** @brief Node desctructor */
Node::~Node()
{
if (action)
delete action;
}
+/** Prints debugging info for the ModelAction associated with this Node */
void Node::print()
{
if (action)
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();
+}
+
+/** This method sets a promise to explore meeting with the given
+ * node.
+ * @param i is the promise index.
+ */
+
+void Node::set_promise(uint32_t i) {
+ if (i>=promises.size())
+ promises.resize(i+1,0);
+ promises[i]=1;
+}
+
+/** This method looks up whether a given promise should be satisfied
+ * by this node.
+ *
+ * @param i is the promise index.
+ * @return true if the promise should be satisfied by the given model action.
+ */
+
+bool Node::get_promise(uint32_t i) {
+ return (i<promises.size())&&(promises[i]==2);
+}
+
+/** This method 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]==1) {
+ promises[i]=2;
+ while (i>0) {
+ i--;
+ if (promises[i]==2)
+ promises[i]=1;
+ }
+ return true;
+ }
+ }
+ return false;
+}
+
+/** This method 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]==1)
+ 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) {
+ for(unsigned int i=0;i<future_values.size();i++)
+ if (future_values[i]==value)
+ return false;
+
+ future_values.push_back(value);
+ 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.
+ * @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());
+}
+
+
+
+/**
+ * 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());
}
+/**
+ * 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);
}
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_index<future_values.size());
+ return future_values[future_index];
+}
+
+/**
+ * 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() {
+ 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;
}
}
NodeStack::NodeStack()
+ : total_nodes(0)
{
node_list.push_back(new Node());
+ total_nodes++;
iter = node_list.begin();
}
DBG();
ASSERT(!node_list.empty());
+ node_list_t::iterator it=iter;
+ it++;
- 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);
- act->create_cv(get_head()->get_action());
- node_list.push_back(new Node(act, get_head()));
+ if (it != node_list.end()) {
iter++;
+ return (*iter)->get_action();
}
- return (*iter)->get_action();
+
+ /* Record action */
+ get_head()->explore_child(act);
+ 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()
projects / c11tester.git / blobdiff