X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=model.cc;h=73d212d0166d2ac3d2fc7368f25afac0333ac491;hb=12b1a10eeff58161619bafcfd8e288b3e2c76621;hp=744fec5e17a27ef75b07a2bca068ff344e951ee8;hpb=f8bac60ca108ab3d7729c0254ff80819e6d8c121;p=model-checker.git

diff --git a/model.cc b/model.cc
index 744fec5..73d212d 100644
--- a/model.cc
+++ b/model.cc
@@ -12,6 +12,7 @@
 #include "promise.h"
 #include "datarace.h"
 #include "mutex.h"
+#include "threads.h"
 
 #define INITIAL_THREAD_ID	0
 
@@ -99,6 +100,12 @@ int ModelChecker::get_num_threads()
 	return priv->next_thread_id;
 }
 
+/** @return The currently executing Thread. */
+Thread * ModelChecker::get_current_thread()
+{
+	return scheduler->get_current_thread();
+}
+
 /** @return a sequence number for a new ModelAction */
 modelclock_t ModelChecker::get_next_seq_num()
 {
@@ -139,6 +146,9 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr)
 	ModelAction *next = node_stack->get_next()->get_action();
 
 	if (next == diverge) {
+		if (earliest_diverge == NULL || *diverge < *earliest_diverge)
+			earliest_diverge=diverge;
+
 		Node *nextnode = next->get_node();
 		/* Reached divergence point */
 		if (nextnode->increment_promise()) {
@@ -158,8 +168,12 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr)
 			Node *node = nextnode->get_parent();
 			tid = node->get_next_backtrack();
 			node_stack->pop_restofstack(1);
+			if (diverge==earliest_diverge) {
+				earliest_diverge=node->get_action();
+			}
 		}
 		DEBUG("*** Divergence point ***\n");
+
 		diverge = NULL;
 	} else {
 		tid = next->get_tid();
@@ -181,6 +195,7 @@ bool ModelChecker::next_execution()
 	DBG();
 
 	num_executions++;
+
 	if (isfinalfeasible()) {
 		printf("Earliest divergence point since last feasible execution:\n");
 		if (earliest_diverge)
@@ -192,15 +207,15 @@ bool ModelChecker::next_execution()
 		num_feasible_executions++;
 	}
 
+	DEBUG("Number of acquires waiting on pending release sequences: %lu\n",
+			pending_acq_rel_seq->size());
+
 	if (isfinalfeasible() || DBG_ENABLED())
 		print_summary();
 
 	if ((diverge = get_next_backtrack()) == NULL)
 		return false;
 
-	if (earliest_diverge == NULL || *diverge < *earliest_diverge)
-		earliest_diverge=diverge;
-
 	if (DBG_ENABLED()) {
 		printf("Next execution will diverge at:\n");
 		diverge->print();
@@ -471,11 +486,11 @@ bool ModelChecker::process_write(ModelAction *curr)
  * (e.g., ATOMIC_{READ,WRITE,RMW,LOCK}, etc.)
  *
  * @param curr The current action
- * @return True if synchronization was updated
+ * @return True if synchronization was updated or a thread completed
  */
 bool ModelChecker::process_thread_action(ModelAction *curr)
 {
-	bool synchronized = false;
+	bool updated = false;
 
 	switch (curr->get_type()) {
 	case THREAD_CREATE: {
@@ -484,19 +499,29 @@ bool ModelChecker::process_thread_action(ModelAction *curr)
 		break;
 	}
 	case THREAD_JOIN: {
-		Thread *blocking = (Thread *)curr->get_location();
-		ModelAction *act = get_last_action(blocking->get_id());
-		curr->synchronize_with(act);
-		synchronized = true;
+		Thread *waiting, *blocking;
+		waiting = get_thread(curr);
+		blocking = (Thread *)curr->get_location();
+		if (!blocking->is_complete()) {
+			blocking->push_wait_list(curr);
+			scheduler->sleep(waiting);
+		} else {
+			do_complete_join(curr);
+			updated = true; /* trigger rel-seq checks */
+		}
 		break;
 	}
 	case THREAD_FINISH: {
 		Thread *th = get_thread(curr);
 		while (!th->wait_list_empty()) {
 			ModelAction *act = th->pop_wait_list();
-			scheduler->wake(get_thread(act));
+			Thread *wake = get_thread(act);
+			scheduler->wake(wake);
+			do_complete_join(act);
+			updated = true; /* trigger rel-seq checks */
 		}
 		th->complete();
+		updated = true; /* trigger rel-seq checks */
 		break;
 	}
 	case THREAD_START: {
@@ -507,7 +532,7 @@ bool ModelChecker::process_thread_action(ModelAction *curr)
 		break;
 	}
 
-	return synchronized;
+	return updated;
 }
 
 /**
@@ -566,12 +591,9 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
 }
 
 /**
- * @brief Check whether a model action is enabled.
- *
- * Checks whether a lock or join operation would be successful (i.e., is the
- * lock already locked, or is the joined thread already complete). If not, put
- * the action in a waiter list.
- *
+ * This method checks whether a model action is enabled at the given point.
+ * At this point, it checks whether a lock operation would be successful at this point.
+ * If not, it puts the thread in a waiter list.
  * @param curr is the ModelAction to check whether it is enabled.
  * @return a bool that indicates whether the action is enabled.
  */
@@ -584,12 +606,6 @@ bool ModelChecker::check_action_enabled(ModelAction *curr) {
 			lock_waiters_map->get_safe_ptr(curr->get_location())->push_back(curr);
 			return false;
 		}
-	} else if (curr->get_type() == THREAD_JOIN) {
-		Thread *blocking = (Thread *)curr->get_location();
-		if (!blocking->is_complete()) {
-			blocking->push_wait_list(curr);
-			return false;
-		}
 	}
 
 	return true;
@@ -615,7 +631,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
 
 	if (!check_action_enabled(curr)) {
 		/* Make the execution look like we chose to run this action
-		 * much later, when a lock/join can succeed */
+		 * much later, when a lock is actually available to release */
 		get_current_thread()->set_pending(curr);
 		scheduler->sleep(get_current_thread());
 		return get_next_thread(NULL);
@@ -699,6 +715,19 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
 	return get_next_thread(curr);
 }
 
+/**
+ * Complete a THREAD_JOIN operation, by synchronizing with the THREAD_FINISH
+ * operation from the Thread it is joining with. Must be called after the
+ * completion of the Thread in question.
+ * @param join The THREAD_JOIN action
+ */
+void ModelChecker::do_complete_join(ModelAction *join)
+{
+	Thread *blocking = (Thread *)join->get_location();
+	ModelAction *act = get_last_action(blocking->get_id());
+	join->synchronize_with(act);
+}
+
 void ModelChecker::check_curr_backtracking(ModelAction * curr) {
 	Node *currnode = curr->get_node();
 	Node *parnode = currnode->get_parent();
@@ -1306,6 +1335,8 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_
 		}
 
 		if (updated) {
+			/* Re-check all pending release sequences */
+			work_queue->push_back(CheckRelSeqWorkEntry(NULL));
 			/* Re-check act for mo_graph edges */
 			work_queue->push_back(MOEdgeWorkEntry(act));
 
@@ -1457,6 +1488,7 @@ bool ModelChecker::resolve_promises(ModelAction *write)
 			//Make sure the promise's value matches the write's value
 			ASSERT(promise->get_value() == write->get_value());
 
+			delete(promise);
 			promises->erase(promises->begin() + promise_index);
 			resolved = true;
 		} else
@@ -1659,12 +1691,35 @@ void ModelChecker::remove_thread(Thread *t)
 	scheduler->remove_thread(t);
 }
 
+/**
+ * @brief Get a Thread reference by its ID
+ * @param tid The Thread's ID
+ * @return A Thread reference
+ */
+Thread * ModelChecker::get_thread(thread_id_t tid)
+{
+	return thread_map->get(id_to_int(tid));
+}
+
+/**
+ * @brief Get a reference to the Thread in which a ModelAction was executed
+ * @param act The ModelAction
+ * @return A Thread reference
+ */
+Thread * ModelChecker::get_thread(ModelAction *act)
+{
+	return get_thread(act->get_tid());
+}
+
 /**
  * Switch from a user-context to the "master thread" context (a.k.a. system
  * context). This switch is made with the intention of exploring a particular
  * model-checking action (described by a ModelAction object). Must be called
  * from a user-thread context.
- * @param act The current action that will be explored. Must not be NULL.
+ *
+ * @param act The current action that will be explored. May be NULL only if
+ * trace is exiting via an assertion (see ModelChecker::set_assert and
+ * ModelChecker::has_asserted).
  * @return Return status from the 'swap' call (i.e., success/fail, 0/-1)
  */
 int ModelChecker::switch_to_master(ModelAction *act)