#include "schedule.h"
#include "common.h"
+#define INITIAL_THREAD_ID 0
+
ModelChecker *model;
ModelChecker::ModelChecker()
{
- /* First thread created (system_thread) will have id 1 */
- this->used_thread_id = 0;
+ /* First thread created will have id (INITIAL_THREAD_ID + 1) */
+ this->used_thread_id = INITIAL_THREAD_ID;
/* Initialize default scheduler */
this->scheduler = new Scheduler();
+ num_executions = 0;
this->current_action = NULL;
+ this->exploring = NULL;
+ this->nextThread = THREAD_ID_T_NONE;
rootNode = new TreeNode(NULL);
currentNode = rootNode;
delete rootNode;
}
-void ModelChecker::assign_id(Thread *t)
+void ModelChecker::reset_to_initial_state()
+{
+ DEBUG("+++ Resetting to initial state +++\n");
+ std::map<thread_id_t, class Thread *>::iterator it;
+ for (it = thread_map.begin(); it != thread_map.end(); it++) {
+ delete (*it).second;
+ }
+ thread_map.clear();
+ action_trace = new action_list_t();
+ currentNode = rootNode;
+ current_action = NULL;
+ used_thread_id = INITIAL_THREAD_ID;
+ /* scheduler reset ? */
+}
+
+int ModelChecker::get_next_id()
{
- t->set_id(++used_thread_id);
+ return ++used_thread_id;
}
-void ModelChecker::add_system_thread(Thread *t)
+Thread * ModelChecker::schedule_next_thread()
{
- this->system_thread = t;
+ Thread *t;
+ if (nextThread == THREAD_ID_T_NONE)
+ return NULL;
+ t = thread_map[nextThread];
+ if (t == NULL)
+ DEBUG("*** error: thread not in thread_map: id = %d\n", nextThread);
+ return t;
}
-ModelAction *ModelChecker::get_last_conflict(ModelAction *act)
+/*
+ * get_next_replay_thread() - 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.
+ */
+thread_id_t ModelChecker::get_next_replay_thread()
+{
+ ModelAction *next;
+ thread_id_t tid;
+
+ next = exploring->get_state();
+
+ if (next == exploring->get_diverge()) {
+ TreeNode *node = next->get_node();
+
+ /* Reached divergence point; discard our current 'exploring' */
+ DEBUG("*** Discard 'Backtrack' object ***\n");
+ tid = node->getNextBacktrack();
+ delete exploring;
+ exploring = NULL;
+ } else {
+ tid = next->get_tid();
+ }
+ DEBUG("*** ModelChecker chose next thread = %d ***\n", tid);
+ return tid;
+}
+
+thread_id_t ModelChecker::advance_backtracking_state()
+{
+ /* Have we completed exploring the preselected path? */
+ if (exploring == NULL)
+ return THREAD_ID_T_NONE;
+
+ /* Else, we are trying to replay an execution */
+ exploring->advance_state();
+ if (exploring->get_state() == NULL)
+ DEBUG("*** error: reached end of backtrack trace\n");
+
+ return get_next_replay_thread();
+}
+
+bool ModelChecker::next_execution()
+{
+ num_executions++;
+ print_summary();
+ if ((exploring = model->get_next_backtrack()) == NULL)
+ return false;
+ model->reset_to_initial_state();
+ nextThread = get_next_replay_thread();
+ return true;
+}
+
+ModelAction * ModelChecker::get_last_conflict(ModelAction *act)
{
- void *loc = act->get_location();
action_type type = act->get_type();
- thread_id_t id = act->get_tid();
switch (type) {
case THREAD_CREATE:
default:
break;
}
+ /* linear search: from most recent to oldest */
action_list_t::reverse_iterator rit;
for (rit = action_trace->rbegin(); rit != action_trace->rend(); rit++) {
ModelAction *prev = *rit;
- if (prev->get_location() != loc)
- continue;
- if (type == ATOMIC_READ && prev->get_type() != ATOMIC_WRITE)
- continue;
- /* Conflict from the same thread is not really a conflict */
- if (id == prev->get_tid())
- return NULL;
- return prev;
+ if (act->is_dependent(prev))
+ return prev;
}
return NULL;
}
if (node->setBacktrack(act->get_tid()) != 0)
return;
- printf("Setting backtrack: conflict = %d, instead tid = %d\n",
+ DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n",
prev->get_tid(), act->get_tid());
- prev->print();
- act->print();
+ if (DBG_ENABLED()) {
+ prev->print();
+ act->print();
+ }
Backtrack *back = new Backtrack(prev, action_trace);
backtrack_list.push_back(back);
}
+Backtrack * ModelChecker::get_next_backtrack()
+{
+ Backtrack *next;
+ if (backtrack_list.empty())
+ return NULL;
+ next = backtrack_list.back();
+ backtrack_list.pop_back();
+ return next;
+}
+
void ModelChecker::check_current_action(void)
{
ModelAction *next = this->current_action;
DEBUG("trying to push NULL action...\n");
return;
}
+ current_action = NULL;
+ nextThread = advance_backtracking_state();
next->set_node(currentNode);
set_backtracking(next);
currentNode = currentNode->exploreChild(next->get_tid());
this->action_trace->push_back(next);
}
-void ModelChecker::print_trace(void)
+void ModelChecker::print_summary(void)
{
action_list_t::iterator it;
printf("\n");
printf("---------------------------------------------------------------------\n");
+ printf("Number of executions: %d\n", num_executions);
printf("Total nodes created: %d\n\n", TreeNode::getTotalNodes());
+ scheduler->print();
+
+ printf("Trace:\n\n");
+
for (it = action_trace->begin(); it != action_trace->end(); it++) {
DBG();
(*it)->print();
int ModelChecker::add_thread(Thread *t)
{
thread_map[t->get_id()] = t;
+ scheduler->add_thread(t);
return 0;
}
+void ModelChecker::remove_thread(Thread *t)
+{
+ scheduler->remove_thread(t);
+}
+
int ModelChecker::switch_to_master(ModelAction *act)
{
- Thread *old, *next;
+ Thread *old;
DBG();
old = thread_current();
set_current_action(act);
old->set_state(THREAD_READY);
- next = system_thread;
- return old->swap(next);
+ return Thread::swap(old, get_system_context());
}
ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int value)
act->value = value;
}
+bool ModelAction::is_read()
+{
+ return type == ATOMIC_READ;
+}
+
+bool ModelAction::is_write()
+{
+ return type == ATOMIC_WRITE;
+}
+
+bool ModelAction::is_acquire()
+{
+ switch (order) {
+ case memory_order_acquire:
+ case memory_order_acq_rel:
+ case memory_order_seq_cst:
+ return true;
+ default:
+ return false;
+ }
+}
+
+bool ModelAction::is_release()
+{
+ switch (order) {
+ case memory_order_release:
+ case memory_order_acq_rel:
+ case memory_order_seq_cst:
+ return true;
+ default:
+ return false;
+ }
+}
+
+bool ModelAction::same_var(ModelAction *act)
+{
+ return location == act->location;
+}
+
+bool ModelAction::same_thread(ModelAction *act)
+{
+ return tid == act->tid;
+}
+
+bool ModelAction::is_dependent(ModelAction *act)
+{
+ if (!is_read() && !is_write())
+ return false;
+ if (!act->is_read() && !act->is_write())
+ return false;
+ if (same_var(act) && !same_thread(act) &&
+ (is_write() || act->is_write()))
+ return true;
+ return false;
+}
+
void ModelAction::print(void)
{
const char *type_str;
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