#include <stdio.h>
#include "model.h"
+#include "action.h"
+#include "nodestack.h"
#include "schedule.h"
+#include "snapshot-interface.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;
+ :
/* Initialize default scheduler */
- this->scheduler = new Scheduler();
+ scheduler(new Scheduler()),
+ /* First thread created will have id INITIAL_THREAD_ID */
+ next_thread_id(INITIAL_THREAD_ID),
+ used_sequence_numbers(0),
- this->current_action = NULL;
+ num_executions(0),
+ current_action(NULL),
+ diverge(NULL),
+ nextThread(THREAD_ID_T_NONE),
+ action_trace(new action_list_t()),
+ thread_map(new std::map<int, class Thread *>),
+ node_stack(new NodeStack()),
+ next_backtrack(NULL)
+{
}
ModelChecker::~ModelChecker()
{
- delete this->scheduler;
+ std::map<int, class Thread *>::iterator it;
+ for (it = thread_map->begin(); it != thread_map->end(); it++)
+ delete (*it).second;
+ delete thread_map;
+
+ delete action_trace;
+
+ delete node_stack;
+ delete scheduler;
+}
+
+void ModelChecker::reset_to_initial_state()
+{
+ DEBUG("+++ Resetting to initial state +++\n");
+ node_stack->reset_execution();
+ current_action = NULL;
+ next_thread_id = INITIAL_THREAD_ID;
+ used_sequence_numbers = 0;
+ nextThread = 0;
+ next_backtrack = NULL;
+ snapshotObject->backTrackBeforeStep(0);
+}
+
+thread_id_t ModelChecker::get_next_id()
+{
+ return next_thread_id++;
+}
+
+int ModelChecker::get_num_threads()
+{
+ return next_thread_id;
+}
+
+int ModelChecker::get_next_seq_num()
+{
+ return ++used_sequence_numbers;
+}
+
+Thread * ModelChecker::schedule_next_thread()
+{
+ Thread *t;
+ if (nextThread == THREAD_ID_T_NONE)
+ return NULL;
+ t = (*thread_map)[id_to_int(nextThread)];
+
+ ASSERT(t != NULL);
+
+ return t;
+}
+
+/*
+ * 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;
+
+ /* Have we completed exploring the preselected path? */
+ if (diverge == NULL)
+ return THREAD_ID_T_NONE;
+
+ /* Else, we are trying to replay an execution */
+ next = node_stack->get_next()->get_action();
+
+ if (next == diverge) {
+ Node *node = next->get_node();
+
+ /* Reached divergence point */
+ DEBUG("*** Divergence point ***\n");
+ tid = node->get_next_backtrack();
+ diverge = NULL;
+ } else {
+ tid = next->get_tid();
+ }
+ DEBUG("*** ModelChecker chose next thread = %d ***\n", tid);
+ return tid;
+}
+
+bool ModelChecker::next_execution()
+{
+ DBG();
+
+ num_executions++;
+ print_summary();
+ if ((diverge = model->get_next_backtrack()) == NULL)
+ return false;
+
+ if (DBG_ENABLED()) {
+ printf("Next execution will diverge at:\n");
+ diverge->print();
+ }
+
+ model->reset_to_initial_state();
+ return true;
+}
+
+ModelAction * ModelChecker::get_last_conflict(ModelAction *act)
+{
+ action_type type = act->get_type();
+
+ switch (type) {
+ case THREAD_CREATE:
+ case THREAD_YIELD:
+ case THREAD_JOIN:
+ return NULL;
+ case ATOMIC_READ:
+ case ATOMIC_WRITE:
+ 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 (act->is_dependent(prev))
+ return prev;
+ }
+ return NULL;
}
-void ModelChecker::assign_id(struct thread *t)
+void ModelChecker::set_backtracking(ModelAction *act)
{
- t->id = ++this->used_thread_id;
+ ModelAction *prev;
+ Node *node;
+ Thread *t = get_thread(act->get_tid());
+
+ prev = get_last_conflict(act);
+ if (prev == NULL)
+ return;
+
+ node = prev->get_node();
+
+ while (!node->is_enabled(t))
+ t = t->get_parent();
+
+ /* Check if this has been explored already */
+ if (node->has_been_explored(t->get_id()))
+ return;
+
+ if (!next_backtrack || *prev > *next_backtrack)
+ next_backtrack = prev;
+
+ /* If this is a new backtracking point, mark the tree */
+ if (!node->set_backtrack(t->get_id()))
+ return;
+ DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n",
+ prev->get_tid(), t->get_id());
+ if (DBG_ENABLED()) {
+ prev->print();
+ act->print();
+ }
}
-void ModelChecker::add_system_thread(struct thread *t)
+ModelAction * ModelChecker::get_next_backtrack()
{
- this->system_thread = t;
+ ModelAction *next = next_backtrack;
+ next_backtrack = NULL;
+ return next;
}
void ModelChecker::check_current_action(void)
{
- if (this->current_action)
- this->action_trace.push_back(this->current_action);
- else
+ Node *currnode;
+
+ ModelAction *curr = this->current_action;
+ current_action = NULL;
+ if (!curr) {
DEBUG("trying to push NULL action...\n");
+ return;
+ }
+
+ curr = node_stack->explore_action(curr);
+ nextThread = get_next_replay_thread();
+
+ currnode = curr->get_node();
+
+ if (!currnode->backtrack_empty())
+ if (!next_backtrack || *curr > *next_backtrack)
+ next_backtrack = curr;
+
+ set_backtracking(curr);
+ this->action_trace->push_back(curr);
}
-void ModelChecker::print_trace(void)
+void ModelChecker::print_summary(void)
{
- std::list<class ModelAction *>::iterator it;
+ printf("\n");
+ printf("Number of executions: %d\n", num_executions);
+ printf("Total nodes created: %d\n", Node::get_total_nodes());
+
+ scheduler->print();
+
+ print_list(action_trace);
+ printf("\n");
+}
+
+void ModelChecker::print_list(action_list_t *list)
+{
+ action_list_t::iterator it;
+
+ printf("---------------------------------------------------------------------\n");
+ printf("Trace:\n");
- for (it = action_trace.begin(); it != action_trace.end(); it++) {
- DBG();
+ for (it = list->begin(); it != list->end(); it++) {
(*it)->print();
}
+ printf("---------------------------------------------------------------------\n");
}
-ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int value)
-{
- struct thread *t = thread_current();
- ModelAction *act = this;
-
- act->type = type;
- act->order = order;
- act->location = loc;
- act->tid = t->id;
- act->value = value;
-}
-
-void ModelAction::print(void)
-{
- const char *type_str;
- switch (this->type) {
- case THREAD_CREATE:
- type_str = "thread create";
- break;
- case THREAD_YIELD:
- type_str = "thread yield";
- break;
- case THREAD_JOIN:
- type_str = "thread join";
- break;
- case ATOMIC_READ:
- type_str = "atomic read";
- break;
- case ATOMIC_WRITE:
- type_str = "atomic write";
- break;
- default:
- type_str = "unknown type";
- }
+int ModelChecker::add_thread(Thread *t)
+{
+ (*thread_map)[id_to_int(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;
- printf("Thread: %d\tAction: %s\tMO: %d\tLoc: %#014zx\tValue: %d\n", tid, type_str, order, (size_t)location, value);
+ DBG();
+ old = thread_current();
+ set_current_action(act);
+ old->set_state(THREAD_READY);
+ return Thread::swap(old, get_system_context());
}