#include "schedule.h"
#include "snapshot-interface.h"
#include "common.h"
+#include "clockvector.h"
#define INITIAL_THREAD_ID 0
ModelChecker *model;
+/** @brief Constructor */
ModelChecker::ModelChecker()
:
/* Initialize default scheduler */
diverge(NULL),
nextThread(THREAD_ID_T_NONE),
action_trace(new action_list_t()),
- thread_map(new std::map<int, class Thread *>),
+ thread_map(new std::map<int, Thread *>),
obj_thrd_map(new std::map<void *, std::vector<action_list_t> >()),
thrd_last_action(new std::vector<ModelAction *>(1)),
node_stack(new NodeStack()),
{
}
+/** @brief Destructor */
ModelChecker::~ModelChecker()
{
- std::map<int, class Thread *>::iterator it;
+ std::map<int, Thread *>::iterator it;
for (it = thread_map->begin(); it != thread_map->end(); it++)
delete (*it).second;
delete thread_map;
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");
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;
}
-int ModelChecker::get_next_seq_num()
+/** @returns a sequence number for a new ModelAction */
+modelclock_t 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;
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()
{
next = node_stack->get_next()->get_action();
if (next == diverge) {
- Node *node = next->get_node();
+ Node *node = next->get_node()->get_parent();
/* Reached divergence point */
DEBUG("*** Divergence point ***\n");
return tid;
}
+/**
+ * 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();
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;
if (prev == NULL)
return;
- node = prev->get_node();
+ node = prev->get_node()->get_parent();
while (!node->is_enabled(t))
t = t->get_parent();
if (node->has_been_explored(t->get_id()))
return;
+ /* Cache the latest backtracking point */
if (!next_backtrack || *prev > *next_backtrack)
next_backtrack = prev;
Node *currnode;
ModelAction *curr = this->current_action;
+ ModelAction *tmp;
current_action = NULL;
if (!curr) {
DEBUG("trying to push NULL action...\n");
return;
}
- /* TODO: if get_last_action() is NULL, sync with parent thread */
- curr = node_stack->explore_action(curr, get_last_action(curr->get_tid()));
+ 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();
+ currnode = curr->get_node()->get_parent();
if (!currnode->backtrack_empty())
if (!next_backtrack || *curr > *next_backtrack)
add_action_to_lists(curr);
}
+/**
+ * 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)
{
action_trace->push_back(act);
return (*thrd_last_action)[id_to_int(tid)];
}
-void ModelChecker::print_summary(void)
+ModelAction * ModelChecker::get_parent_action(thread_id_t tid)
{
- printf("\n");
- printf("Number of executions: %d\n", num_executions);
- printf("Total nodes created: %d\n", Node::get_total_nodes());
+ ModelAction *parent = get_last_action(tid);
+ if (!parent)
+ parent = get_thread(tid)->get_creation();
+ return parent;
+}
- scheduler->print();
+ClockVector * ModelChecker::get_cv(thread_id_t tid) {
+ return get_parent_action(tid)->get_cv();
+}
- print_list(action_trace);
- printf("\n");
+/**
+ * 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<action_list_t> *thrd_lists = &(*obj_thrd_map)[curr->get_location()];
+ unsigned int i;
+
+ ASSERT(curr->is_read());
+
+ /* Track whether this object has been initialized */
+ bool initialized = false;
+
+ 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 per-thread that "happens before" curr */
+ if (act->happens_before(curr)) {
+ initialized = true;
+ break;
+ }
+ }
+ }
+
+ if (!initialized) {
+ /* TODO: need a more informative way of reporting errors */
+ printf("ERROR: may read from uninitialized atomic\n");
+ }
+
+ if (DBG_ENABLED() || !initialized) {
+ printf("Reached read action:\n");
+ curr->print();
+ printf("Printing may_read_from\n");
+ curr->get_node()->print_may_read_from();
+ printf("End printing may_read_from\n");
+ }
+
+ ASSERT(initialized);
}
-void ModelChecker::print_list(action_list_t *list)
+static void print_list(action_list_t *list)
{
action_list_t::iterator it;
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;
projects / model-checker.git / blobdiff