X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=model.cc;h=f447c1dfa50e98139b4b1b30a7cb5d9d5a6a5060;hb=996d51da9229031b9d7841c2f3d3b7629db2cba9;hp=19194cda06a766ccb84b1674b6fb5142bcc4bef4;hpb=3ec8b2cabc09653e410e28531669102d2bab449b;p=model-checker.git

diff --git a/model.cc b/model.cc
index 19194cd..f447c1d 100644
--- a/model.cc
+++ b/model.cc
@@ -1,45 +1,314 @@
 #include <stdio.h>
 
 #include "model.h"
+#include "action.h"
+#include "tree.h"
 #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 DefaultScheduler();
+	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;
+	action_trace = new action_list_t();
 }
 
 ModelChecker::~ModelChecker()
 {
+	delete action_trace;
 	delete this->scheduler;
+	delete rootNode;
+}
+
+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()
+{
+	return ++used_thread_id;
+}
+
+Thread * ModelChecker::schedule_next_thread()
+{
+	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;
+}
+
+/*
+ * 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)
+{
+	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::set_backtracking(ModelAction *act)
+{
+	ModelAction *prev;
+	TreeNode *node;
+
+	prev = get_last_conflict(act);
+	if (prev == NULL)
+		return;
+
+	node = prev->get_node();
+
+	/* Check if this has been explored already */
+	if (node->hasBeenExplored(act->get_tid()))
+		return;
+	/* If this is a new backtracking point, mark the tree */
+	if (node->setBacktrack(act->get_tid()) != 0)
+		return;
+
+	DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n",
+			prev->get_tid(), act->get_tid());
+	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;
+
+	if (!next) {
+		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_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();
+	}
+	printf("---------------------------------------------------------------------\n");
 }
 
-void ModelChecker::assign_id(struct thread *t)
+int ModelChecker::add_thread(Thread *t)
 {
-	t->id = ++this->used_thread_id;
+	thread_map[t->get_id()] = t;
+	scheduler->add_thread(t);
+	return 0;
 }
 
-void ModelChecker::add_system_thread(struct thread *t)
+void ModelChecker::remove_thread(Thread *t)
 {
-	this->system_thread = t;
+	scheduler->remove_thread(t);
+}
+
+int ModelChecker::switch_to_master(ModelAction *act)
+{
+	Thread *old;
+
+	DBG();
+	old = thread_current();
+	set_current_action(act);
+	old->set_state(THREAD_READY);
+	return Thread::swap(old, get_system_context());
 }
 
 ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int value)
 {
-	struct thread *t = thread_current();
+	Thread *t = thread_current();
 	ModelAction *act = this;
 
 	act->type = type;
 	act->order = order;
 	act->location = loc;
-	act->tid = t->id;
+	act->tid = t->get_id();
 	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;