X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=action.cc;h=c6504cd388d0f44f6ec72c038d36996b79fad882;hb=38b76fe373e538f275cb3a864a6e919664dc9bda;hp=3fda30de4bf7e425ac99fe95d5c30aca198965d5;hpb=70525635cea4c0622d30571c7028c1c293950bb5;p=model-checker.git

diff --git a/action.cc b/action.cc
index 3fda30d..c6504cd 100644
--- a/action.cc
+++ b/action.cc
@@ -7,6 +7,9 @@
 #include "action.h"
 #include "clockvector.h"
 #include "common.h"
+#include "threads.h"
+
+#define ACTION_INITIAL_CLOCK 0
 
 ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, uint64_t value) :
 	type(type),
@@ -14,44 +17,66 @@ ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, uint
 	location(loc),
 	value(value),
 	reads_from(NULL),
+	seq_number(ACTION_INITIAL_CLOCK),
 	cv(NULL)
 {
 	Thread *t = thread_current();
 	this->tid = t->get_id();
-	this->seq_number = model->get_next_seq_num();
 }
 
+/** @brief ModelAction destructor */
 ModelAction::~ModelAction()
 {
-	if (cv)
-		delete cv;
+	/**
+	 * We can't free the clock vector:
+	 * Clock vectors are snapshotting state. When we delete model actions,
+	 * they are at the end of the node list and have invalid old clock
+	 * vectors which have already been rolled back to an unallocated state.
+	 */
+
+	/*
+	 if (cv)
+		delete cv; */
+}
+
+void ModelAction::copy_from_new(ModelAction *newaction)
+{
+	seq_number = newaction->seq_number;
 }
 
-void ModelAction::copy_from_new(ModelAction *newaction) {
-	seq_number=newaction->seq_number;
+void ModelAction::set_seq_number(modelclock_t num)
+{
+	ASSERT(seq_number == ACTION_INITIAL_CLOCK);
+	seq_number = num;
 }
 
-bool ModelAction::is_mutex_op() const {
+bool ModelAction::is_mutex_op() const
+{
 	return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK;
 }
 
-bool ModelAction::is_lock() const {
+bool ModelAction::is_lock() const
+{
 	return type == ATOMIC_LOCK;
 }
 
-bool ModelAction::is_unlock() const {
+bool ModelAction::is_unlock() const
+{
 	return type == ATOMIC_UNLOCK;
 }
 
-bool ModelAction::is_trylock() const {
+bool ModelAction::is_trylock() const
+{
 	return type == ATOMIC_TRYLOCK;
 }
 
-bool ModelAction::is_success_lock() const {
+bool ModelAction::is_success_lock() const
+{
 	return type == ATOMIC_LOCK || (type == ATOMIC_TRYLOCK && value == VALUE_TRYSUCCESS);
 }
 
-bool ModelAction::is_failed_trylock() const {
+bool ModelAction::is_failed_trylock() const
+{
 	return (type == ATOMIC_TRYLOCK && value == VALUE_TRYFAILED);
 }
 
@@ -130,8 +155,8 @@ bool ModelAction::same_thread(const ModelAction *act) const
 }
 
 void ModelAction::copy_typeandorder(ModelAction * act) {
-	this->type=act->type;
-	this->order=act->order;
+	this->type = act->type;
+	this->order = act->order;
 }
 
 /** This method changes an existing read part of an RMW action into either:
@@ -201,11 +226,16 @@ bool ModelAction::is_conflicting_lock(const ModelAction *act) const
 	return false;
 }
 
+/**
+ * Create a new clock vector for this action. Note that this function allows a
+ * user to clobber (and leak) a ModelAction's existing clock vector. A user
+ * should ensure that the vector has already either been rolled back
+ * (effectively "freed") or freed.
+ *
+ * @param parent A ModelAction from which to inherit a ClockVector
+ */
 void ModelAction::create_cv(const ModelAction *parent)
 {
-	if (cv)
-		delete cv;
-
 	if (parent)
 		cv = new ClockVector(parent->cv, this);
 	else
@@ -219,28 +249,41 @@ void ModelAction::set_try_lock(bool obtainedlock) {
 		value=VALUE_TRYFAILED;
 }
 
-/** Update the model action's read_from action */
-void ModelAction::read_from(const ModelAction *act)
+/**
+ * Update the model action's read_from action
+ * @param act The action to read from; should be a write
+ * @return True if this read established synchronization
+ */
+bool ModelAction::read_from(const ModelAction *act)
 {
 	ASSERT(cv);
 	reads_from = act;
 	if (act != NULL && this->is_acquire()) {
 		rel_heads_list_t release_heads;
 		model->get_release_seq_heads(this, &release_heads);
+		int num_heads = release_heads.size();
 		for (unsigned int i = 0; i < release_heads.size(); i++)
-			synchronize_with(release_heads[i]);
+			if (!synchronize_with(release_heads[i])) {
+				model->set_bad_synchronization();
+				num_heads--;
+			}
+		return num_heads > 0;
 	}
+	return false;
 }
 
 /**
  * Synchronize the current thread with the thread corresponding to the
  * ModelAction parameter.
  * @param act The ModelAction to synchronize with
+ * @return True if this is a valid synchronization; false otherwise
  */
-void ModelAction::synchronize_with(const ModelAction *act) {
-	ASSERT(*act < *this || type == THREAD_JOIN || type == ATOMIC_LOCK );
-	model->check_promises(cv, act->cv);
+bool ModelAction::synchronize_with(const ModelAction *act) {
+	if (*this < *act && type != THREAD_JOIN && type != ATOMIC_LOCK)
+		return false;
+	model->check_promises(act->get_tid(), cv, act->cv);
 	cv->merge(act->cv);
+	return true;
 }
 
 bool ModelAction::has_synchronized_with(const ModelAction *act) const
@@ -259,7 +302,8 @@ bool ModelAction::happens_before(const ModelAction *act) const
 	return act->cv->synchronized_since(this);
 }
 
-void ModelAction::print(void) const
+/** @brief Print nicely-formatted info about this ModelAction */
+void ModelAction::print() const
 {
 	const char *type_str, *mo_str;
 	switch (this->type) {