X-Git-Url: http://plrg.eecs.uci.edu/git/?p=cdsspec-compiler.git;a=blobdiff_plain;f=nodestack.cc;h=b4f75e0336a3afdc3978b7ecb086e459423df455;hp=743cb864452589f615d937220fe9440bf8bad093;hb=caa1df880547acce2804221c8e6995170a5121eb;hpb=15fabc6f4e6591341940a8087a8dd088af59bb5c

diff --git a/nodestack.cc b/nodestack.cc
index 743cb86..b4f75e0 100644
--- a/nodestack.cc
+++ b/nodestack.cc
@@ -192,26 +192,39 @@ bool Node::misc_empty() {
 
 
 /**
- * Adds a value from a weakly ordered future write to backtrack to.
+ * Adds a value from a weakly ordered future write to backtrack to. This
+ * operation may "fail" if the future value has already been run (within some
+ * sloppiness window of this expiration), or if the futurevalues set has
+ * reached its maximum.
+ * @see model_params.maxfuturevalues
+ *
  * @param value is the value to backtrack to.
+ * @return True if the future value was successully added; false otherwise
  */
 bool Node::add_future_value(uint64_t value, modelclock_t expiration) {
-	int suitableindex=-1;
+	int idx = -1; /* Highest index where value is found */
 	for (unsigned int i = 0; i < future_values.size(); i++) {
 		if (future_values[i].value == value) {
-			if (future_values[i].expiration>=expiration)
+			if (expiration <= future_values[i].expiration)
 				return false;
-			if (future_index < ((int) i)) {
-				suitableindex=i;
-			}
+			idx = i;
 		}
 	}
-
-	if (suitableindex!=-1) {
-		future_values[suitableindex].expiration=expiration;
+	if (idx > future_index) {
+		/* Future value hasn't been explored; update expiration */
+		future_values[idx].expiration = expiration;
 		return true;
+	} else if (idx >= 0 && expiration <= future_values[idx].expiration + model->params.expireslop) {
+		/* Future value has been explored and is within the "sloppy" window */
+		return false;
 	}
-	struct future_value newfv={value, expiration};
+
+	/* Limit the size of the future-values set */
+	if (model->params.maxfuturevalues > 0 &&
+			(int)future_values.size() >= model->params.maxfuturevalues)
+		return false;
+
+	struct future_value newfv = {value, expiration};
 	future_values.push_back(newfv);
 	return true;
 }