Fixing an out of bound bug.

[jpf-core.git] / src / main / gov / nasa / jpf / listener / StateReducer.java

diff --git a/src/main/gov/nasa/jpf/listener/StateReducer.java b/src/main/gov/nasa/jpf/listener/StateReducer.java
index 6d5a026deaf20e552e058bcae870085ee912154b..93043fa33d7b9a09491bdb3ac33df09f44e014d3 100644 (file)
--- a/src/main/gov/nasa/jpf/listener/StateReducer.java
+++ b/src/main/gov/nasa/jpf/listener/StateReducer.java
@@ -76,7 +76,7 @@ public class StateReducer extends ListenerAdapter {
   private HashSet<String> backtrackSet;
   private HashMap<Integer, HashSet<Integer>> conflictPairMap;
   // Map choicelist with start index
-//  private HashMap<Integer[],Integer> choiceListStartIndexMap;
+  //  private HashMap<Integer[],Integer> choiceListStartIndexMap;
 
   // Map that represents graph G
   // (i.e., visible operation dependency graph (VOD Graph)
@@ -87,6 +87,8 @@ public class StateReducer extends ListenerAdapter {
   private HashSet<Integer> visitedStateSet;
   // Current state
   private int stateId;
+  // Previous choice number
+  private int prevChoiceValue;
 
   public StateReducer(Config config, JPF jpf) {
     debugMode = config.getBoolean("debug_state_transition", false);
@@ -104,6 +106,7 @@ public class StateReducer extends ListenerAdapter {
     vodGraphMap = new HashMap<>();
     visitedStateSet = new HashSet<>();
     stateId = -1;
+    prevChoiceValue = -1;
     initializeStateReduction();
   }
 
@@ -238,7 +241,7 @@ public class StateReducer extends ListenerAdapter {
           // Advance choice counter for sub-graphs
           choiceCounter++;
           // Do this for every CG after finishing each backtrack list
-          if (icsCG.getNextChoice() == -1) {
+          if (icsCG.getNextChoice() == -1 || visitedStateSet.contains(stateId)) {
             int event = cgMap.get(icsCG);
             LinkedList<Integer[]> choiceLists = backtrackMap.get(event);
             if (choiceLists != null && choiceLists.peekFirst() != null) {
@@ -295,26 +298,20 @@ public class StateReducer extends ListenerAdapter {
               " which is " + detail + " Transition: " + transition + "\n");
     }
     if (stateReductionMode) {
-      // Line 19 in the paper page 11 (see the heading note above)
-      stateId = search.getStateId();
-      if (visitedStateSet.contains(stateId)) {
-        // VOD graph is not updated if the "new" state has been seen earlier
-        return;
-      }
-      // Add state ID into the visited state set
-      visitedStateSet.add(stateId);
       // Update vodGraph
       int currChoice = choiceCounter - 1;
-      int prevChoice = currChoice - 1;
-      if (currChoice < 0) {
-        // Current choice has to be at least 0 (initial case can be -1)
+      if (currChoice < 0 || currChoice > choices.length - 1 || choices[currChoice] == -1 || prevChoiceValue == choices[currChoice]) {
+        // Handle all corner cases (e.g., out of bound values)
         return;
       }
-      // Current choice and previous choice values could be -1 (since we use -1 as the end-of-array condition)
-      int currChoiceValue = (choices[currChoice] == -1) ? 0 : choices[currChoice];
       // When current choice is 0, previous choice could be -1
-      int prevChoiceValue = (prevChoice == -1) ? -1 : choices[prevChoice];
-      updateVODGraph(prevChoiceValue, currChoiceValue);
+      updateVODGraph(prevChoiceValue, choices[currChoice]);
+      // Current choice becomes previous choice in the next iteration
+      prevChoiceValue = choices[currChoice];
+      // Line 19 in the paper page 11 (see the heading note above)
+      stateId = search.getStateId();
+      // Add state ID into the visited state set
+      visitedStateSet.add(stateId);
     }
   }