X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=Robust%2Fsrc%2FAnalysis%2FSSJava%2FDefinitelyWrittenCheck.java;h=63cbf7e38c71bfc338063c0e285980de4d55077a;hb=4e6e3860c77a7d2a8817976d909533a74ce8d02c;hp=437c22ba42f435486af51df1076e8e527cd0ab72;hpb=f7d7d8aff5cfc5e0462c687d2b2c6815d5d202b3;p=IRC.git

diff --git a/Robust/src/Analysis/SSJava/DefinitelyWrittenCheck.java b/Robust/src/Analysis/SSJava/DefinitelyWrittenCheck.java
index 437c22ba..63cbf7e3 100644
--- a/Robust/src/Analysis/SSJava/DefinitelyWrittenCheck.java
+++ b/Robust/src/Analysis/SSJava/DefinitelyWrittenCheck.java
@@ -1,5 +1,9 @@
 package Analysis.SSJava;
 
+import java.io.BufferedWriter;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.Enumeration;
 import java.util.HashSet;
 import java.util.Hashtable;
 import java.util.Iterator;
@@ -9,21 +13,26 @@ import java.util.Stack;
 
 import Analysis.CallGraph.CallGraph;
 import Analysis.Loops.LoopFinder;
+import IR.ClassDescriptor;
 import IR.Descriptor;
 import IR.FieldDescriptor;
 import IR.MethodDescriptor;
 import IR.Operation;
 import IR.State;
 import IR.TypeDescriptor;
+import IR.TypeExtension;
 import IR.Flat.FKind;
 import IR.Flat.FlatCall;
+import IR.Flat.FlatElementNode;
 import IR.Flat.FlatFieldNode;
 import IR.Flat.FlatLiteralNode;
 import IR.Flat.FlatMethod;
 import IR.Flat.FlatNode;
 import IR.Flat.FlatOpNode;
+import IR.Flat.FlatSetElementNode;
 import IR.Flat.FlatSetFieldNode;
 import IR.Flat.TempDescriptor;
+import IR.Tree.Modifiers;
 import Util.Pair;
 
 public class DefinitelyWrittenCheck {
@@ -32,6 +41,8 @@ public class DefinitelyWrittenCheck {
   State state;
   CallGraph callGraph;
 
+  int debugcount = 0;
+
   // maps a descriptor to its known dependents: namely
   // methods or tasks that call the descriptor's method
   // AND are part of this analysis (reachable from main)
@@ -39,142 +50,218 @@ public class DefinitelyWrittenCheck {
 
   // maps a flat node to its WrittenSet: this keeps all heap path overwritten
   // previously.
-  private Hashtable<FlatNode, Set<NTuple<Descriptor>>> mapFlatNodeToWrittenSet;
+  private Hashtable<FlatNode, Set<NTuple<Descriptor>>> mapFlatNodeToMustWriteSet;
 
   // maps a temp descriptor to its heap path
   // each temp descriptor has a unique heap path since we do not allow any
   // alias.
   private Hashtable<Descriptor, NTuple<Descriptor>> mapHeapPath;
 
+  // maps a temp descriptor to its composite location
+  private Hashtable<Descriptor, NTuple<Location>> mapDescriptorToLocationStrPath;
+
   // maps a flat method to the READ that is the set of heap path that is
   // expected to be written before method invocation
-  private Hashtable<FlatMethod, Set<NTuple<Descriptor>>> mapFlatMethodToRead;
+  private Hashtable<FlatMethod, Set<NTuple<Descriptor>>> mapFlatMethodToReadSet;
+
+  // maps a flat method to the must-write set that is the set of heap path that
+  // is overwritten on every possible path during method invocation
+  private Hashtable<FlatMethod, Set<NTuple<Descriptor>>> mapFlatMethodToMustWriteSet;
+
+  // maps a flat method to the DELETE SET that is a set of heap path to shared
+  // locations that are
+  // written to but not overwritten by the higher value
+  private Hashtable<FlatMethod, Set<NTuple<Descriptor>>> mapFlatMethodToDeleteSet;
+
+  // maps a flat method to the S SET that is a set of heap path to shared
+  // locations that are overwritten by the higher value
+  private Hashtable<FlatMethod, SharedLocMappingSet> mapFlatMethodToSharedLocMappingSet;
+
+  // maps a flat method to the may-wirte set that is the set of heap path that
+  // might be written to
+  private Hashtable<FlatMethod, Set<NTuple<Descriptor>>> mapFlatMethodToMayWriteSet;
+
+  // maps a call site to the read set contributed by all callees
+  private Hashtable<FlatNode, Set<NTuple<Descriptor>>> mapFlatNodeToBoundReadSet;
+
+  // maps a call site to the must write set contributed by all callees
+  private Hashtable<FlatNode, Set<NTuple<Descriptor>>> mapFlatNodeToBoundMustWriteSet;
 
-  // maps a flat method to the OVERWRITE that is the set of heap path that is
-  // overwritten on every possible path during method invocation
-  private Hashtable<FlatMethod, Set<NTuple<Descriptor>>> mapFlatMethodToOverWrite;
+  // maps a call site to the may read set contributed by all callees
+  private Hashtable<FlatNode, Set<NTuple<Descriptor>>> mapFlatNodeToBoundMayWriteSet;
 
   // points to method containing SSJAVA Loop
   private MethodDescriptor methodContainingSSJavaLoop;
 
   // maps a flatnode to definitely written analysis mapping M
-  private Hashtable<FlatNode, Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>>> definitelyWrittenResults;
+  private Hashtable<FlatNode, Hashtable<NTuple<Descriptor>, Set<WriteAge>>> mapFlatNodetoEventLoopMap;
 
   // maps a method descriptor to its current summary during the analysis
   // then analysis reaches fixed-point, this mapping will have the final summary
   // for each method descriptor
-  private Hashtable<MethodDescriptor, Hashtable<NTuple<Descriptor>, SharedLocState>> mapMethodDescriptorToCompleteClearingSummary;
+  private Hashtable<MethodDescriptor, ClearingSummary> mapMethodDescriptorToCompleteClearingSummary;
 
   // maps a method descriptor to the merged incoming caller's current
   // overwritten status
-  private Hashtable<MethodDescriptor, Hashtable<NTuple<Descriptor>, SharedLocState>> mapMethodDescriptorToInitialClearingSummary;
+  private Hashtable<MethodDescriptor, ClearingSummary> mapMethodDescriptorToInitialClearingSummary;
 
   // maps a flat node to current partial results
-  private Hashtable<FlatNode, Hashtable<NTuple<Descriptor>, SharedLocState>> mapFlatNodeToClearingSummary;
+  private Hashtable<FlatNode, ClearingSummary> mapFlatNodeToClearingSummary;
 
   // maps shared location to the set of descriptors which belong to the shared
   // location
-  private Hashtable<Pair<NTuple<Descriptor>, Location>, Set<Descriptor>> mapSharedLocation2DescriptorSet;
 
-  // data structure for merging current state
-  private Hashtable<Pair<NTuple<Descriptor>, Location>, Boolean> mapHeapPathLocation2Flag;
+  // keep current descriptors to visit in fixed-point interprocedural analysis,
+  private Stack<MethodDescriptor> methodDescriptorsToVisitStack;
+
+  // when analyzing flatcall, need to re-schedule set of callee
+  private Set<MethodDescriptor> calleesToEnqueue;
+
+  private Set<ReadSummary> possibleCalleeReadSummarySetToCaller;
+
+  public static final String arrayElementFieldName = "___element_";
+  static protected Hashtable<TypeDescriptor, FieldDescriptor> mapTypeToArrayField;
+
+  private Set<ClearingSummary> possibleCalleeCompleteSummarySetToCaller;
+
+  // maps a method descriptor to the merged incoming caller's current
+  // reading status
+  // it is for setting clearance flag when all read set is overwritten
+  private Hashtable<MethodDescriptor, ReadSummary> mapMethodDescriptorToReadSummary;
+
+  private MultiSourceMap<Location, Descriptor> mapLocationPathToMayWrittenSet;
+
+  private Hashtable<MethodDescriptor, MultiSourceMap<Location, Descriptor>> mapMethodToSharedWriteMapping;
+
+  private Hashtable<FlatNode, SharedLocMappingSet> mapFlatNodeToSharedLocMapping;
+
+  private Hashtable<Location, Set<Descriptor>> mapSharedLocationToCoverSet;
+
+  private LinkedList<MethodDescriptor> sortedDescriptors;
 
   private FlatNode ssjavaLoopEntrance;
   private LoopFinder ssjavaLoop;
   private Set<FlatNode> loopIncElements;
 
   private Set<NTuple<Descriptor>> calleeUnionBoundReadSet;
-  private Set<NTuple<Descriptor>> calleeIntersectBoundOverWriteSet;
+  private Set<NTuple<Descriptor>> calleeIntersectBoundMustWriteSet;
+  private Set<NTuple<Descriptor>> calleeUnionBoundMayWriteSet;
+  private Set<NTuple<Descriptor>> calleeUnionBoundDeleteSet;
+  private SharedLocMappingSet calleeIntersectBoundSharedSet;
+
+  private Hashtable<Descriptor, Location> mapDescToLocation;
 
   private TempDescriptor LOCAL;
 
+  public static int MAXAGE = 1;
+
   public DefinitelyWrittenCheck(SSJavaAnalysis ssjava, State state) {
     this.state = state;
     this.ssjava = ssjava;
     this.callGraph = ssjava.getCallGraph();
-    this.mapFlatNodeToWrittenSet = new Hashtable<FlatNode, Set<NTuple<Descriptor>>>();
+    this.mapFlatNodeToMustWriteSet = new Hashtable<FlatNode, Set<NTuple<Descriptor>>>();
     this.mapDescriptorToSetDependents = new Hashtable<Descriptor, Set<MethodDescriptor>>();
     this.mapHeapPath = new Hashtable<Descriptor, NTuple<Descriptor>>();
-    this.mapFlatMethodToRead = new Hashtable<FlatMethod, Set<NTuple<Descriptor>>>();
-    this.mapFlatMethodToOverWrite = new Hashtable<FlatMethod, Set<NTuple<Descriptor>>>();
-    this.definitelyWrittenResults =
-        new Hashtable<FlatNode, Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>>>();
+    this.mapDescriptorToLocationStrPath = new Hashtable<Descriptor, NTuple<Location>>();
+    this.mapFlatMethodToReadSet = new Hashtable<FlatMethod, Set<NTuple<Descriptor>>>();
+    this.mapFlatMethodToMustWriteSet = new Hashtable<FlatMethod, Set<NTuple<Descriptor>>>();
+    this.mapFlatMethodToMayWriteSet = new Hashtable<FlatMethod, Set<NTuple<Descriptor>>>();
+    this.mapFlatNodetoEventLoopMap =
+        new Hashtable<FlatNode, Hashtable<NTuple<Descriptor>, Set<WriteAge>>>();
     this.calleeUnionBoundReadSet = new HashSet<NTuple<Descriptor>>();
-    this.calleeIntersectBoundOverWriteSet = new HashSet<NTuple<Descriptor>>();
+    this.calleeIntersectBoundMustWriteSet = new HashSet<NTuple<Descriptor>>();
+    this.calleeUnionBoundMayWriteSet = new HashSet<NTuple<Descriptor>>();
 
     this.mapMethodDescriptorToCompleteClearingSummary =
-        new Hashtable<MethodDescriptor, Hashtable<NTuple<Descriptor>, SharedLocState>>();
+        new Hashtable<MethodDescriptor, ClearingSummary>();
     this.mapMethodDescriptorToInitialClearingSummary =
-        new Hashtable<MethodDescriptor, Hashtable<NTuple<Descriptor>, SharedLocState>>();
-    this.mapFlatNodeToClearingSummary =
-        new Hashtable<FlatNode, Hashtable<NTuple<Descriptor>, SharedLocState>>();
-    this.mapSharedLocation2DescriptorSet =
-        new Hashtable<Pair<NTuple<Descriptor>, Location>, Set<Descriptor>>();
-    this.mapHeapPathLocation2Flag = new Hashtable<Pair<NTuple<Descriptor>, Location>, Boolean>();
+        new Hashtable<MethodDescriptor, ClearingSummary>();
+    this.methodDescriptorsToVisitStack = new Stack<MethodDescriptor>();
+    this.calleesToEnqueue = new HashSet<MethodDescriptor>();
+    this.possibleCalleeCompleteSummarySetToCaller = new HashSet<ClearingSummary>();
+    this.mapTypeToArrayField = new Hashtable<TypeDescriptor, FieldDescriptor>();
     this.LOCAL = new TempDescriptor("LOCAL");
+    this.mapDescToLocation = new Hashtable<Descriptor, Location>();
+    this.possibleCalleeReadSummarySetToCaller = new HashSet<ReadSummary>();
+    this.mapMethodDescriptorToReadSummary = new Hashtable<MethodDescriptor, ReadSummary>();
+    this.mapFlatNodeToBoundReadSet = new Hashtable<FlatNode, Set<NTuple<Descriptor>>>();
+    this.mapFlatNodeToBoundMustWriteSet = new Hashtable<FlatNode, Set<NTuple<Descriptor>>>();
+    this.mapFlatNodeToBoundMayWriteSet = new Hashtable<FlatNode, Set<NTuple<Descriptor>>>();
+    this.mapSharedLocationToCoverSet = new Hashtable<Location, Set<Descriptor>>();
+    this.mapFlatNodeToSharedLocMapping = new Hashtable<FlatNode, SharedLocMappingSet>();
+    this.mapFlatMethodToDeleteSet = new Hashtable<FlatMethod, Set<NTuple<Descriptor>>>();
+    this.calleeUnionBoundDeleteSet = new HashSet<NTuple<Descriptor>>();
+    this.calleeIntersectBoundSharedSet = new SharedLocMappingSet();
+    this.mapFlatMethodToSharedLocMappingSet = new Hashtable<FlatMethod, SharedLocMappingSet>();
+    this.mapLocationPathToMayWrittenSet = new MultiSourceMap<Location, Descriptor>();
+    this.mapMethodToSharedWriteMapping =
+        new Hashtable<MethodDescriptor, MultiSourceMap<Location, Descriptor>>();
   }
 
   public void definitelyWrittenCheck() {
     if (!ssjava.getAnnotationRequireSet().isEmpty()) {
-      methodReadOverWriteAnalysis();
-      writtenAnalyis();
-      sharedLocationAnalysis();
-      checkSharedLocationResult();
-    }
-  }
+      initialize();
+      computeSharedCoverSet();
 
-  private void checkSharedLocationResult() {
+      System.out.println("#");
+      System.out.println(mapLocationPathToMayWrittenSet);
 
-    Hashtable<NTuple<Descriptor>, SharedLocState> result =
-        mapFlatNodeToClearingSummary.get(ssjavaLoopEntrance);
-    System.out.println("checkSharedLocationResult=" + result);
-    Set<NTuple<Descriptor>> hpKeySet = result.keySet();
-    for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
-      NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
-      SharedLocState state = result.get(hpKey);
-      Set<Location> locKeySet = state.getLocationSet();
-      for (Iterator iterator2 = locKeySet.iterator(); iterator2.hasNext();) {
-        Location locKey = (Location) iterator2.next();
-        if (!state.getFlag(locKey)) {
-          throw new Error(
-              "Some concrete locations of the shared abstract location are not cleared at the same time.");
-        }
-      }
-    }
+      methodReadWriteSetAnalysis();
 
+      // sharedLocAnalysis();
+
+      // eventLoopAnalysis();
+
+      // XXXXXXX
+      // methodReadWriteSetAnalysis();
+      // methodReadWriteSetAnalysisToEventLoopBody();
+      // eventLoopAnalysis();
+      // XXXXXXX
+      // sharedLocationAnalysis();
+      // checkSharedLocationResult();
+    }
   }
 
-  private void sharedLocationAnalysis() {
-    // verify that all concrete locations of shared location are cleared out at
-    // the same time once per the out-most loop
+  private void sharedLocAnalysis() {
 
-    computeReadSharedDescriptorSet();
+    // perform method READ/OVERWRITE analysis
+    LinkedList<MethodDescriptor> descriptorListToAnalyze =
+        (LinkedList<MethodDescriptor>) sortedDescriptors.clone();
 
-    Set<MethodDescriptor> methodDescriptorsToAnalyze = new HashSet<MethodDescriptor>();
-    methodDescriptorsToAnalyze.addAll(ssjava.getAnnotationRequireSet());
+    // current descriptors to visit in fixed-point interprocedural analysis,
+    // prioritized by
+    // dependency in the call graph
+    methodDescriptorsToVisitStack.clear();
 
-    LinkedList<MethodDescriptor> sortedDescriptors = topologicalSort(methodDescriptorsToAnalyze);
+    descriptorListToAnalyze.removeFirst();
 
-    Stack<MethodDescriptor> methodDescriptorsToVisitStack = new Stack<MethodDescriptor>();
     Set<MethodDescriptor> methodDescriptorToVistSet = new HashSet<MethodDescriptor>();
-    methodDescriptorToVistSet.addAll(sortedDescriptors);
+    methodDescriptorToVistSet.addAll(descriptorListToAnalyze);
 
-    while (!sortedDescriptors.isEmpty()) {
-      MethodDescriptor md = sortedDescriptors.removeLast();
+    while (!descriptorListToAnalyze.isEmpty()) {
+      MethodDescriptor md = descriptorListToAnalyze.removeFirst();
       methodDescriptorsToVisitStack.add(md);
     }
 
     // analyze scheduled methods until there are no more to visit
     while (!methodDescriptorsToVisitStack.isEmpty()) {
+      // start to analyze leaf node
       MethodDescriptor md = methodDescriptorsToVisitStack.pop();
       FlatMethod fm = state.getMethodFlat(md);
 
-      sharedLocation_analyzeMethod(fm, (md.equals(methodContainingSSJavaLoop)));
+      Set<NTuple<Descriptor>> deleteSet = new HashSet<NTuple<Descriptor>>();
+
+      sharedLoc_analyzeMethod(fm, deleteSet);
+      System.out.println("deleteSet result=" + deleteSet);
 
-      if (true) {
+      Set<NTuple<Descriptor>> prevDeleteSet = mapFlatMethodToDeleteSet.get(fm);
+
+      if (!deleteSet.equals(prevDeleteSet)) {
+        mapFlatMethodToDeleteSet.put(fm, deleteSet);
 
         // results for callee changed, so enqueue dependents caller for
-        // further analysis
+        // further
+        // analysis
         Iterator<MethodDescriptor> depsItr = getDependents(md).iterator();
         while (depsItr.hasNext()) {
           MethodDescriptor methodNext = depsItr.next();
@@ -189,72 +276,46 @@ public class DefinitelyWrittenCheck {
 
     }
 
-    Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
-    flatNodesToVisit.add(ssjavaLoopEntrance);
-
   }
 
-  private void sharedLocation_analyzeMethod(FlatMethod fm, boolean onlyVisitSSJavaLoop) {
-
+  private void sharedLoc_analyzeMethod(FlatMethod fm, Set<NTuple<Descriptor>> deleteSet) {
     if (state.SSJAVADEBUG) {
-      System.out.println("Definitely written for shared locations Analyzing: " + fm + " "
-          + onlyVisitSSJavaLoop);
+      System.out.println("SSJAVA: Definite clearance for shared locations Analyzing: " + fm);
     }
 
+    sharedLoc_analyzeBody(fm, deleteSet, false);
+
+  }
+
+  private void sharedLoc_analyzeBody(FlatNode startNode, Set<NTuple<Descriptor>> deleteSet,
+      boolean isEventLoopBody) {
+
     // intraprocedural analysis
     Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
-
-    if (onlyVisitSSJavaLoop) {
-      flatNodesToVisit.add(ssjavaLoopEntrance);
-    } else {
-      flatNodesToVisit.add(fm);
-    }
+    flatNodesToVisit.add(startNode);
 
     while (!flatNodesToVisit.isEmpty()) {
       FlatNode fn = flatNodesToVisit.iterator().next();
       flatNodesToVisit.remove(fn);
 
-      Hashtable<NTuple<Descriptor>, SharedLocState> curr =
-          new Hashtable<NTuple<Descriptor>, SharedLocState>();
+      SharedLocMappingSet currSharedSet = new SharedLocMappingSet();
 
-      mapHeapPathLocation2Flag.clear();
       for (int i = 0; i < fn.numPrev(); i++) {
         FlatNode prevFn = fn.getPrev(i);
-        Hashtable<NTuple<Descriptor>, SharedLocState> in = mapFlatNodeToClearingSummary.get(prevFn);
+        SharedLocMappingSet in = mapFlatNodeToSharedLocMapping.get(prevFn);
         if (in != null) {
-          mergeSharedAnaylsis(curr, in);
+          merge(currSharedSet, in);
         }
       }
-      // merge flag status
-      Set<NTuple<Descriptor>> hpKeySet = curr.keySet();
-      for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
-        NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
-        SharedLocState currState = curr.get(hpKey);
-        Set<Location> locKeySet = currState.getMap().keySet();
-        for (Iterator iterator2 = locKeySet.iterator(); iterator2.hasNext();) {
-          Location locKey = (Location) iterator2.next();
-          Pair<Set<Descriptor>, Boolean> pair = currState.getMap().get(locKey);
-          boolean currentFlag = pair.getSecond().booleanValue();
-          Boolean inFlag = mapHeapPathLocation2Flag.get(new Pair(hpKey, locKey));
-          boolean newFlag = currentFlag | inFlag.booleanValue();
-          if (currentFlag != newFlag) {
-            currState.getMap().put(locKey, new Pair(pair.getFirst(), new Boolean(newFlag)));
-          }
-        }
-      }
-
-      sharedLocation_nodeActions(fn, curr, onlyVisitSSJavaLoop);
 
-      Hashtable<NTuple<Descriptor>, SharedLocState> clearingPrev =
-          mapFlatNodeToClearingSummary.get(fn);
-
-      if (!curr.equals(clearingPrev)) {
-        mapFlatNodeToClearingSummary.put(fn, curr);
+      sharedLoc_nodeActions(fn, currSharedSet, deleteSet, isEventLoopBody);
 
+      SharedLocMappingSet mustSetPrev = mapFlatNodeToSharedLocMapping.get(fn);
+      if (!currSharedSet.equals(mustSetPrev)) {
+        mapFlatNodeToSharedLocMapping.put(fn, currSharedSet);
         for (int i = 0; i < fn.numNext(); i++) {
           FlatNode nn = fn.getNext(i);
-
-          if (!onlyVisitSSJavaLoop || (onlyVisitSSJavaLoop && loopIncElements.contains(nn))) {
+          if ((!isEventLoopBody) || loopIncElements.contains(nn)) {
             flatNodesToVisit.add(nn);
           }
 
@@ -265,50 +326,71 @@ public class DefinitelyWrittenCheck {
 
   }
 
-  private void sharedLocation_nodeActions(FlatNode fn,
-      Hashtable<NTuple<Descriptor>, SharedLocState> curr, boolean isSSJavaLoop) {
+  private void sharedLoc_nodeActions(FlatNode fn, SharedLocMappingSet curr,
+      Set<NTuple<Descriptor>> deleteSet, boolean isEventLoopBody) {
+
+    SharedLocMappingSet killSet = new SharedLocMappingSet();
+    SharedLocMappingSet genSet = new SharedLocMappingSet();
 
     TempDescriptor lhs;
     TempDescriptor rhs;
     FieldDescriptor fld;
+
     switch (fn.kind()) {
 
     case FKind.FlatOpNode: {
-      FlatOpNode fon = (FlatOpNode) fn;
-      lhs = fon.getDest();
-      rhs = fon.getLeft();
 
-      if (fon.getOp().getOp() == Operation.ASSIGN) {
-        if (rhs.getType().isImmutable() && isSSJavaLoop) {
-          // in ssjavaloop, we need to take care about reading local variables!
-          NTuple<Descriptor> rhsHeapPath = new NTuple<Descriptor>();
-          NTuple<Descriptor> lhsHeapPath = new NTuple<Descriptor>();
-          rhsHeapPath.add(LOCAL);
-          lhsHeapPath.add(LOCAL);
-          if (!lhs.getSymbol().startsWith("neverused")) {
-            readLocation(curr, rhsHeapPath, rhs);
-            writeLocation(curr, lhsHeapPath, lhs);
-          }
-        }
-      }
+      if (isEventLoopBody) {
+        FlatOpNode fon = (FlatOpNode) fn;
+        lhs = fon.getDest();
+        rhs = fon.getLeft();
 
-    }
-      break;
+        if (!lhs.getSymbol().startsWith("neverused")) {
 
-    case FKind.FlatFieldNode:
-    case FKind.FlatElementNode: {
+          if (rhs.getType().isImmutable()) {
+            NTuple<Descriptor> rhsHeapPath = computePath(rhs);
 
-      FlatFieldNode ffn = (FlatFieldNode) fn;
-      lhs = ffn.getDst();
-      rhs = ffn.getSrc();
-      fld = ffn.getField();
+            if (rhs.getType().getExtension() instanceof Location
+                && lhs.getType().getExtension() instanceof CompositeLocation) {
+              // rhs is field!
+              Location rhsLoc = (Location) rhs.getType().getExtension();
 
-      // read field
-      NTuple<Descriptor> srcHeapPath = mapHeapPath.get(rhs);
-      NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(srcHeapPath.getList());
+              CompositeLocation lhsCompLoc = (CompositeLocation) lhs.getType().getExtension();
+              Location dstLoc = lhsCompLoc.get(lhsCompLoc.getSize() - 1);
 
-      if (fld.getType().isImmutable()) {
-        readLocation(curr, fldHeapPath, fld);
+              NTuple<Descriptor> heapPath = new NTuple<Descriptor>();
+              for (int i = 0; i < rhsHeapPath.size() - 1; i++) {
+                heapPath.add(rhsHeapPath.get(i));
+              }
+
+              NTuple<Descriptor> writeHeapPath = new NTuple<Descriptor>();
+              writeHeapPath.addAll(heapPath);
+              writeHeapPath.add(lhs);
+
+              System.out.println("VAR WRITE:" + fn);
+              System.out.println("LHS TYPE EXTENSION=" + lhs.getType().getExtension());
+              System.out.println("RHS TYPE EXTENSION=" + rhs.getType().getExtension()
+                  + " HEAPPATH=" + rhsHeapPath);
+
+              // computing gen/kill set
+              computeKILLSetForWrite(curr, heapPath, dstLoc, killSet);
+              if (!dstLoc.equals(rhsLoc)) {
+                computeGENSetForHigherWrite(curr, heapPath, dstLoc, lhs, genSet);
+                deleteSet.remove(writeHeapPath);
+              } else {
+                computeGENSetForSharedWrite(curr, heapPath, dstLoc, lhs, genSet);
+                deleteSet.add(writeHeapPath);
+              }
+
+            }
+
+            // System.out.println("fieldLoc=" + fieldLoc + " srcLoc=" + srcLoc);
+            System.out.println("KILLSET=" + killSet);
+            System.out.println("GENSet=" + genSet);
+            System.out.println("DELETESET=" + deleteSet);
+
+          }
+        }
       }
 
     }
@@ -317,289 +399,1182 @@ public class DefinitelyWrittenCheck {
     case FKind.FlatSetFieldNode:
     case FKind.FlatSetElementNode: {
 
-      FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
-      lhs = fsfn.getDst();
-      fld = fsfn.getField();
+      if (fn.kind() == FKind.FlatSetFieldNode) {
+        FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
+        lhs = fsfn.getDst();
+        fld = fsfn.getField();
+        rhs = fsfn.getSrc();
+      } else {
+        FlatSetElementNode fsen = (FlatSetElementNode) fn;
+        lhs = fsen.getDst();
+        rhs = fsen.getSrc();
+        TypeDescriptor td = lhs.getType().dereference();
+        fld = getArrayField(td);
+      }
 
-      // write(field)
-      NTuple<Descriptor> lhsHeapPath = computePath(lhs);
-      NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
+      // shared loc extension
+      Location srcLoc = getLocation(rhs);
+      Location fieldLoc = (Location) fld.getType().getExtension();
+      if (ssjava.isSharedLocation(fieldLoc)) {
+        // only care the case that loc(f) is shared location
+        // write(field)
+        NTuple<Descriptor> lhsHeapPath = computePath(lhs);
+        NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
+        fldHeapPath.add(fld);
 
-      if (fld.getType().isImmutable()) {
-        writeLocation(curr, fldHeapPath, fld);
+        // computing gen/kill set
+        computeKILLSetForWrite(curr, lhsHeapPath, fieldLoc, killSet);
+        if (!fieldLoc.equals(srcLoc)) {
+          System.out.println("LOC IS DIFFERENT");
+          computeGENSetForHigherWrite(curr, lhsHeapPath, fieldLoc, fld, genSet);
+          deleteSet.remove(fldHeapPath);
+        } else {
+          computeGENSetForSharedWrite(curr, lhsHeapPath, fieldLoc, fld, genSet);
+          deleteSet.add(fldHeapPath);
+        }
       }
 
+      System.out.println("################");
+      System.out.println("FIELD WRITE:" + fn);
+      System.out.println("fieldLoc=" + fieldLoc + " srcLoc=" + srcLoc);
+      System.out.println("KILLSET=" + killSet);
+      System.out.println("GENSet=" + genSet);
+      System.out.println("DELETESET=" + deleteSet);
+
     }
       break;
 
     case FKind.FlatCall: {
+      FlatCall fc = (FlatCall) fn;
+
+      bindHeapPathCallerArgWithCaleeParamForSharedLoc(fc);
 
+      // generateKILLSetForFlatCall(fc, curr, readWriteKillSet);
+      // generateGENSetForFlatCall(fc, readWriteGenSet);
+
+      // System.out.println
+      // // only care the case that loc(f) is shared location
+      // // write(field)
+      // NTuple<Descriptor> lhsHeapPath = computePath(lhs);
+      // NTuple<Descriptor> fldHeapPath = new
+      // NTuple<Descriptor>(lhsHeapPath.getList());
+      // fldHeapPath.add(fld);
+      //
+      // // computing gen/kill set
+      // computeKILLSetForWrite(curr, lhsHeapPath, fieldLoc, killSet);
+      // if (!fieldLoc.equals(srcLoc)) {
+      // System.out.println("LOC IS DIFFERENT");
+      // computeGENSetForHigherWrite(curr, lhsHeapPath, fieldLoc, fld, genSet);
+      // deleteSet.remove(fldHeapPath);
+      // } else {
+      // computeGENSetForSharedWrite(curr, lhsHeapPath, fieldLoc, fld, genSet);
+      // deleteSet.add(fldHeapPath);
+      // }
+      // ("FLATCALL:" + fn);
+      // System.out.println("bound DELETE Set=" + calleeUnionBoundDeleteSet);
+      // // System.out.println("KILLSET=" + KILLSet);
+      // // System.out.println("GENSet=" + GENSet);
+      //
     }
-      break;
+    // break;
+
     }
 
+    // computeNewMapping(curr, readWriteKillSet, readWriteGenSet);
+    // System.out.println("#######" + curr);
+
   }
 
-  private void computeReadSharedDescriptorSet() {
-    Set<MethodDescriptor> methodDescriptorsToAnalyze = new HashSet<MethodDescriptor>();
-    methodDescriptorsToAnalyze.addAll(ssjava.getAnnotationRequireSet());
+  private void computeKILLSetForWrite(SharedLocMappingSet curr, NTuple<Descriptor> hp,
+      Location loc, SharedLocMappingSet killSet) {
 
-    for (Iterator iterator = methodDescriptorsToAnalyze.iterator(); iterator.hasNext();) {
-      MethodDescriptor md = (MethodDescriptor) iterator.next();
-      FlatMethod fm = state.getMethodFlat(md);
-      computeReadSharedDescriptorSet_analyzeMethod(fm, md.equals(methodContainingSSJavaLoop));
+    Set<Descriptor> currWriteSet = curr.getWriteSet(hp, loc);
+    if (!currWriteSet.isEmpty()) {
+      killSet.addWriteSet(hp, loc, currWriteSet);
     }
 
   }
 
-  private void computeReadSharedDescriptorSet_analyzeMethod(FlatMethod fm,
-      boolean onlyVisitSSJavaLoop) {
+  private void computeGENSetForHigherWrite(SharedLocMappingSet curr, NTuple<Descriptor> hp,
+      Location loc, Descriptor desc, SharedLocMappingSet genSet) {
 
-    Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
-    Set<FlatNode> visited = new HashSet<FlatNode>();
+    Set<Descriptor> genWriteSet = new HashSet<Descriptor>();
+    genWriteSet.addAll(curr.getWriteSet(hp, loc));
+    genWriteSet.add(desc);
 
-    if (onlyVisitSSJavaLoop) {
-      flatNodesToVisit.add(ssjavaLoopEntrance);
-    } else {
-      flatNodesToVisit.add(fm);
-    }
+    genSet.addWriteSet(hp, loc, genWriteSet);
 
-    while (!flatNodesToVisit.isEmpty()) {
-      FlatNode fn = flatNodesToVisit.iterator().next();
-      flatNodesToVisit.remove(fn);
-      visited.add(fn);
+  }
 
-      computeReadSharedDescriptorSet_nodeActions(fn, onlyVisitSSJavaLoop);
+  private void computeGENSetForSharedWrite(SharedLocMappingSet curr, NTuple<Descriptor> hp,
+      Location loc, Descriptor desc, SharedLocMappingSet genSet) {
 
-      for (int i = 0; i < fn.numNext(); i++) {
-        FlatNode nn = fn.getNext(i);
-        if (!visited.contains(nn)) {
-          if (!onlyVisitSSJavaLoop || (onlyVisitSSJavaLoop && loopIncElements.contains(nn))) {
-            flatNodesToVisit.add(nn);
-          }
-        }
-      }
+    Set<Descriptor> genWriteSet = new HashSet<Descriptor>();
+    genWriteSet.addAll(curr.getWriteSet(hp, loc));
+    genWriteSet.remove(desc);
+
+    if (!genWriteSet.isEmpty()) {
+      genSet.addWriteSet(hp, loc, genWriteSet);
+    }
+  }
 
+  private void merge(SharedLocMappingSet currSharedSet, SharedLocMappingSet in) {
+
+    Set<NTuple<Descriptor>> hpKeySet = in.getHeapPathKeySet();
+    for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+      Set<Location> locSet = in.getLocationKeySet(hpKey);
+      for (Iterator iterator2 = locSet.iterator(); iterator2.hasNext();) {
+        Location locKey = (Location) iterator2.next();
+        Set<Descriptor> writeSet = in.getWriteSet(hpKey, locKey);
+        currSharedSet.intersectWriteSet(hpKey, locKey, writeSet);
+      }
     }
 
   }
 
-  private void computeReadSharedDescriptorSet_nodeActions(FlatNode fn, boolean isSSJavaLoop) {
+  private void checkSharedLocationResult() {
 
-    TempDescriptor lhs;
-    TempDescriptor rhs;
-    FieldDescriptor fld;
+    // mapping of method containing ssjava loop has the final result of
+    // shared location analysis
 
-    switch (fn.kind()) {
-    case FKind.FlatOpNode: {
-      FlatOpNode fon = (FlatOpNode) fn;
-      lhs = fon.getDest();
-      rhs = fon.getLeft();
+    ClearingSummary result =
+        mapMethodDescriptorToCompleteClearingSummary.get(methodContainingSSJavaLoop);
 
-      if (fon.getOp().getOp() == Operation.ASSIGN) {
-        if (rhs.getType().isImmutable() && isSSJavaLoop && (!rhs.getSymbol().startsWith("srctmp"))) {
-          // in ssjavaloop, we need to take care about reading local variables!
-          NTuple<Descriptor> rhsHeapPath = new NTuple<Descriptor>();
-          NTuple<Descriptor> lhsHeapPath = new NTuple<Descriptor>();
-          rhsHeapPath.add(LOCAL);
-          addReadDescriptor(rhsHeapPath, rhs);
+    String str = generateNotClearedResult(result);
+    if (str.length() > 0) {
+      throw new Error(
+          "Following concrete locations of the shared abstract location are not cleared at the same time:\n"
+              + str);
+    }
+
+  }
+
+  private String generateNotClearedResult(ClearingSummary result) {
+    Set<NTuple<Descriptor>> keySet = result.keySet();
+
+    StringBuffer str = new StringBuffer();
+    for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+      SharedStatus status = result.get(hpKey);
+      Hashtable<Location, Pair<Set<Descriptor>, Boolean>> map = status.getMap();
+      Set<Location> locKeySet = map.keySet();
+      for (Iterator iterator2 = locKeySet.iterator(); iterator2.hasNext();) {
+        Location locKey = (Location) iterator2.next();
+        if (status.haveWriteEffect(locKey)) {
+          Pair<Set<Descriptor>, Boolean> pair = map.get(locKey);
+          if (!pair.getSecond().booleanValue()) {
+            // not cleared!
+            str.append("- Concrete locations of the shared location '" + locKey
+                + "' are not cleared out, which are reachable through the heap path '" + hpKey
+                + ".\n");
+          }
         }
       }
-
     }
-      break;
 
-    case FKind.FlatFieldNode:
-    case FKind.FlatElementNode: {
+    return str.toString();
 
-      FlatFieldNode ffn = (FlatFieldNode) fn;
-      lhs = ffn.getDst();
-      rhs = ffn.getSrc();
-      fld = ffn.getField();
+  }
 
-      // read field
-      NTuple<Descriptor> srcHeapPath = mapHeapPath.get(rhs);
-      NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(srcHeapPath.getList());
-      // fldHeapPath.add(fld);
+  private void writeReadMapFile() {
 
-      if (fld.getType().isImmutable()) {
-        addReadDescriptor(fldHeapPath, fld);
-      }
+    String fileName = "SharedLocationReadMap";
 
-      // propagate rhs's heap path to the lhs
-      mapHeapPath.put(lhs, fldHeapPath);
+    try {
+      BufferedWriter bw = new BufferedWriter(new FileWriter(fileName + ".txt"));
 
+      Set<MethodDescriptor> keySet = mapMethodDescriptorToReadSummary.keySet();
+      for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
+        MethodDescriptor mdKey = (MethodDescriptor) iterator.next();
+        ReadSummary summary = mapMethodDescriptorToReadSummary.get(mdKey);
+        bw.write("Method " + mdKey + "::\n");
+        bw.write(summary + "\n\n");
+      }
+      bw.close();
+    } catch (IOException e) {
+      e.printStackTrace();
     }
-      break;
 
-    case FKind.FlatSetFieldNode:
-    case FKind.FlatSetElementNode: {
+  }
 
-      FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
-      lhs = fsfn.getDst();
-      fld = fsfn.getField();
+  private void sharedLocationAnalysis() {
+    // verify that all concrete locations of shared location are cleared out at
+    // the same time once per the out-most loop
 
-      // write(field)
-      NTuple<Descriptor> lhsHeapPath = computePath(lhs);
-      NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
-      // writeLocation(curr, fldHeapPath, fld, getLocation(fld));
+    computeSharedCoverSet();
 
+    if (state.SSJAVADEBUG) {
+      writeReadMapFile();
     }
-      break;
 
-    }
-  }
+    // methodDescriptorsToVisitStack.clear();
+    // methodDescriptorsToVisitStack.add(sortedDescriptors.peekFirst());
 
-  private void addReadDescriptor(NTuple<Descriptor> hp, Descriptor d) {
+    LinkedList<MethodDescriptor> descriptorListToAnalyze =
+        (LinkedList<MethodDescriptor>) sortedDescriptors.clone();
 
-    Location loc = getLocation(d);
+    // current descriptors to visit in fixed-point interprocedural analysis,
+    // prioritized by
+    // dependency in the call graph
+    methodDescriptorsToVisitStack.clear();
 
-    if (loc != null && ssjava.isSharedLocation(loc)) {
+    Set<MethodDescriptor> methodDescriptorToVistSet = new HashSet<MethodDescriptor>();
+    methodDescriptorToVistSet.addAll(descriptorListToAnalyze);
 
-      Pair key = new Pair(hp, loc);
-      Set<Descriptor> set = mapSharedLocation2DescriptorSet.get(key);
-      if (set == null) {
-        set = new HashSet<Descriptor>();
-        mapSharedLocation2DescriptorSet.put(key, set);
-      }
-      set.add(d);
+    while (!descriptorListToAnalyze.isEmpty()) {
+      MethodDescriptor md = descriptorListToAnalyze.removeFirst();
+      methodDescriptorsToVisitStack.add(md);
     }
 
-  }
+    // analyze scheduled methods until there are no more to visit
+    while (!methodDescriptorsToVisitStack.isEmpty()) {
+      MethodDescriptor md = methodDescriptorsToVisitStack.pop();
 
-  private Location getLocation(Descriptor d) {
+      ClearingSummary completeSummary =
+          sharedLocation_analyzeMethod(md, (md.equals(methodContainingSSJavaLoop)));
 
-    if (d instanceof FieldDescriptor) {
-      return (Location) ((FieldDescriptor) d).getType().getExtension();
-    } else {
-      assert d instanceof TempDescriptor;
-      CompositeLocation comp = (CompositeLocation) ((TempDescriptor) d).getType().getExtension();
-      if (comp == null) {
-        return null;
-      } else {
-        return comp.get(comp.getSize() - 1);
-      }
-    }
+      ClearingSummary prevCompleteSummary = mapMethodDescriptorToCompleteClearingSummary.get(md);
 
-  }
+      if (!completeSummary.equals(prevCompleteSummary)) {
 
-  private void writeLocation(Hashtable<NTuple<Descriptor>, SharedLocState> curr,
-      NTuple<Descriptor> hp, Descriptor d) {
-    Location loc = getLocation(d);
-    if (loc != null && ssjava.isSharedLocation(loc)) {
-      SharedLocState state = getState(curr, hp);
-      state.addVar(loc, d);
+        mapMethodDescriptorToCompleteClearingSummary.put(md, completeSummary);
 
-      // if the set v contains all of variables belonging to the shared
-      // location, set flag to true
+        // results for callee changed, so enqueue dependents caller for
+        // further analysis
+        Iterator<MethodDescriptor> depsItr = getDependents(md).iterator();
+        while (depsItr.hasNext()) {
+          MethodDescriptor methodNext = depsItr.next();
+          if (!methodDescriptorsToVisitStack.contains(methodNext)) {
+            methodDescriptorsToVisitStack.add(methodNext);
+          }
+        }
 
-      Set<Descriptor> sharedVarSet =
-          mapSharedLocation2DescriptorSet.get(new Pair<NTuple<Descriptor>, Location>(hp, loc));
+        // if there is set of callee to be analyzed,
+        // add this set into the top of stack
+        Iterator<MethodDescriptor> calleeIter = calleesToEnqueue.iterator();
+        while (calleeIter.hasNext()) {
+          MethodDescriptor mdNext = calleeIter.next();
+          if (!methodDescriptorsToVisitStack.contains(mdNext)) {
+            methodDescriptorsToVisitStack.add(mdNext);
+          }
+        }
+        calleesToEnqueue.clear();
 
-      if (state.getVarSet(loc).containsAll(sharedVarSet)) {
-        state.updateFlag(loc, true);
       }
-    }
-  }
 
-  private void readLocation(Hashtable<NTuple<Descriptor>, SharedLocState> curr,
-      NTuple<Descriptor> hp, Descriptor d) {
-    // remove reading var x from written set
-    Location loc = getLocation(d);
-    if (loc != null && ssjava.isSharedLocation(loc)) {
-      SharedLocState state = getState(curr, hp);
-      state.removeVar(loc, d);
     }
-  }
 
-  private SharedLocState getState(Hashtable<NTuple<Descriptor>, SharedLocState> curr,
-      NTuple<Descriptor> hp) {
-    SharedLocState state = curr.get(hp);
-    if (state == null) {
-      state = new SharedLocState();
-      curr.put(hp, state);
-    }
-    return state;
   }
 
-  private void writtenAnalyis() {
-    // perform second stage analysis: intraprocedural analysis ensure that
-    // all
-    // variables are definitely written in-between the same read
+  private ClearingSummary sharedLocation_analyzeMethod(MethodDescriptor md,
+      boolean onlyVisitSSJavaLoop) {
 
-    // First, identify ssjava loop entrace
-    FlatMethod fm = state.getMethodFlat(methodContainingSSJavaLoop);
+    if (state.SSJAVADEBUG) {
+      System.out.println("SSJAVA: Definite clearance for shared locations Analyzing: " + md);
+    }
+
+    FlatMethod fm = state.getMethodFlat(md);
+
+    // intraprocedural analysis
     Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
-    flatNodesToVisit.add(fm);
 
-    LoopFinder loopFinder = new LoopFinder(fm);
+    // start a new mapping of partial results for each flat node
+    mapFlatNodeToClearingSummary = new Hashtable<FlatNode, ClearingSummary>();
+
+    if (onlyVisitSSJavaLoop) {
+      flatNodesToVisit.add(ssjavaLoopEntrance);
+    } else {
+      flatNodesToVisit.add(fm);
+    }
+
+    Set<FlatNode> returnNodeSet = new HashSet<FlatNode>();
+
+    while (!flatNodesToVisit.isEmpty()) {
+      FlatNode fn = flatNodesToVisit.iterator().next();
+      flatNodesToVisit.remove(fn);
+
+      ClearingSummary curr = new ClearingSummary();
+
+      Set<ClearingSummary> prevSet = new HashSet<ClearingSummary>();
+      for (int i = 0; i < fn.numPrev(); i++) {
+        FlatNode prevFn = fn.getPrev(i);
+        ClearingSummary in = mapFlatNodeToClearingSummary.get(prevFn);
+        if (in != null) {
+          prevSet.add(in);
+        }
+      }
+      mergeSharedLocationAnaylsis(curr, prevSet);
+
+      sharedLocation_nodeActions(md, fn, curr, returnNodeSet, onlyVisitSSJavaLoop);
+      ClearingSummary clearingPrev = mapFlatNodeToClearingSummary.get(fn);
+
+      if (!curr.equals(clearingPrev)) {
+        mapFlatNodeToClearingSummary.put(fn, curr);
+
+        for (int i = 0; i < fn.numNext(); i++) {
+          FlatNode nn = fn.getNext(i);
+
+          if (!onlyVisitSSJavaLoop || (onlyVisitSSJavaLoop && loopIncElements.contains(nn))) {
+            flatNodesToVisit.add(nn);
+          }
+
+        }
+      }
+
+    }
+
+    ClearingSummary completeSummary = new ClearingSummary();
+    Set<ClearingSummary> summarySet = new HashSet<ClearingSummary>();
+
+    if (onlyVisitSSJavaLoop) {
+      // when analyzing ssjava loop,
+      // complete summary is merging of all previous nodes of ssjava loop
+      // entrance
+      for (int i = 0; i < ssjavaLoopEntrance.numPrev(); i++) {
+        ClearingSummary frnSummary =
+            mapFlatNodeToClearingSummary.get(ssjavaLoopEntrance.getPrev(i));
+        if (frnSummary != null) {
+          summarySet.add(frnSummary);
+        }
+      }
+    } else {
+      // merging all exit node summary into the complete summary
+      if (!returnNodeSet.isEmpty()) {
+        for (Iterator iterator = returnNodeSet.iterator(); iterator.hasNext();) {
+          FlatNode frn = (FlatNode) iterator.next();
+          ClearingSummary frnSummary = mapFlatNodeToClearingSummary.get(frn);
+          summarySet.add(frnSummary);
+        }
+      }
+    }
+    mergeSharedLocationAnaylsis(completeSummary, summarySet);
+
+    return completeSummary;
+  }
+
+  private void sharedLocation_nodeActions(MethodDescriptor md, FlatNode fn, ClearingSummary curr,
+      Set<FlatNode> returnNodeSet, boolean isSSJavaLoop) {
+
+    TempDescriptor lhs;
+    TempDescriptor rhs;
+    FieldDescriptor fld;
+    switch (fn.kind()) {
+
+    case FKind.FlatMethod: {
+      FlatMethod fm = (FlatMethod) fn;
+
+      ClearingSummary summaryFromCaller =
+          mapMethodDescriptorToInitialClearingSummary.get(fm.getMethod());
+
+      Set<ClearingSummary> inSet = new HashSet<ClearingSummary>();
+      if (summaryFromCaller != null) {
+        inSet.add(summaryFromCaller);
+        mergeSharedLocationAnaylsis(curr, inSet);
+      }
+
+    }
+      break;
+
+    case FKind.FlatOpNode: {
+      FlatOpNode fon = (FlatOpNode) fn;
+      lhs = fon.getDest();
+      rhs = fon.getLeft();
+
+      if (fon.getOp().getOp() == Operation.ASSIGN) {
+        if (rhs.getType().isImmutable() && isSSJavaLoop) {
+          // in ssjavaloop, we need to take care about reading local variables!
+          NTuple<Descriptor> rhsHeapPath = new NTuple<Descriptor>();
+          NTuple<Descriptor> lhsHeapPath = new NTuple<Descriptor>();
+          rhsHeapPath.add(LOCAL);
+          lhsHeapPath.add(LOCAL);
+          if (!lhs.getSymbol().startsWith("neverused")) {
+            readLocation(md, curr, rhsHeapPath, getLocation(rhs), rhs);
+            writeLocation(md, curr, lhsHeapPath, getLocation(lhs), lhs);
+          }
+        }
+      }
+
+    }
+      break;
+
+    case FKind.FlatSetFieldNode:
+    case FKind.FlatSetElementNode: {
+
+      // x.f=y
+
+      if (fn.kind() == FKind.FlatSetFieldNode) {
+        FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
+        lhs = fsfn.getDst();
+        fld = fsfn.getField();
+        rhs = fsfn.getSrc();
+      } else {
+        FlatSetElementNode fsen = (FlatSetElementNode) fn;
+        lhs = fsen.getDst();
+        rhs = fsen.getSrc();
+        TypeDescriptor td = lhs.getType().dereference();
+        fld = getArrayField(td);
+      }
+
+      // write(field)
+      NTuple<Descriptor> lhsHeapPath = computePath(lhs);
+      NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
+      if (fld.getType().isImmutable()) {
+
+        writeLocation(md, curr, fldHeapPath, getLocation(fld), fld);
+
+        Descriptor desc = fldHeapPath.get(fldHeapPath.size() - 1);
+        if (desc instanceof FieldDescriptor) {
+          NTuple<Descriptor> arrayPath = new NTuple<Descriptor>();
+          for (int i = 0; i < fldHeapPath.size() - 1; i++) {
+            arrayPath.add(fldHeapPath.get(i));
+          }
+          SharedStatus state = getState(curr, arrayPath);
+          state.setWriteEffect(getLocation(desc));
+        }
+
+      } else {
+        // updates reference field case:
+        fldHeapPath.add(fld);
+        updateWriteEffectOnReferenceField(curr, fldHeapPath);
+      }
+
+    }
+      break;
+
+    case FKind.FlatCall: {
+
+      FlatCall fc = (FlatCall) fn;
+
+      if (ssjava.isSSJavaUtil(fc.getMethod().getClassDesc())) {
+        // ssjava util case!
+        // have write effects on the first argument
+
+        if (fc.getArg(0).getType().isArray()) {
+          // updates reference field case:
+          // 2. if there exists a tuple t in sharing summary that starts with
+          // hp(x) then, set flag of tuple t to 'true'
+          NTuple<Descriptor> argHeapPath = computePath(fc.getArg(0));
+
+          Location loc = getLocation(fc.getArg(0));
+          NTuple<Descriptor> newHeapPath = new NTuple<Descriptor>();
+          for (int i = 0; i < argHeapPath.size() - 1; i++) {
+            newHeapPath.add(argHeapPath.get(i));
+          }
+          fld = (FieldDescriptor) argHeapPath.get(argHeapPath.size() - 1);
+          argHeapPath = newHeapPath;
+
+          writeLocation(md, curr, argHeapPath, loc, fld);
+        }
+
+      } else {
+        // find out the set of callees
+        MethodDescriptor mdCallee = fc.getMethod();
+        FlatMethod fmCallee = state.getMethodFlat(mdCallee);
+        Set<MethodDescriptor> setPossibleCallees = new HashSet<MethodDescriptor>();
+        setPossibleCallees.addAll(callGraph.getMethods(mdCallee));
+
+        possibleCalleeCompleteSummarySetToCaller.clear();
+
+        for (Iterator iterator = setPossibleCallees.iterator(); iterator.hasNext();) {
+          MethodDescriptor mdPossibleCallee = (MethodDescriptor) iterator.next();
+          FlatMethod calleeFlatMethod = state.getMethodFlat(mdPossibleCallee);
+
+          addDependent(mdPossibleCallee, // callee
+              md); // caller
+
+          calleesToEnqueue.add(mdPossibleCallee);
+
+          // updates possible callee's initial summary using caller's current
+          // writing status
+          ClearingSummary prevCalleeInitSummary =
+              mapMethodDescriptorToInitialClearingSummary.get(mdPossibleCallee);
+
+          ClearingSummary calleeInitSummary =
+              bindHeapPathOfCalleeCallerEffects(fc, calleeFlatMethod, curr);
+
+          Set<ClearingSummary> inSet = new HashSet<ClearingSummary>();
+          if (prevCalleeInitSummary != null) {
+            inSet.add(prevCalleeInitSummary);
+            mergeSharedLocationAnaylsis(calleeInitSummary, inSet);
+          }
+
+          // if changes, update the init summary
+          // and reschedule the callee for analysis
+          if (!calleeInitSummary.equals(prevCalleeInitSummary)) {
+
+            if (!methodDescriptorsToVisitStack.contains(mdPossibleCallee)) {
+              methodDescriptorsToVisitStack.add(mdPossibleCallee);
+            }
+
+            mapMethodDescriptorToInitialClearingSummary.put(mdPossibleCallee, calleeInitSummary);
+          }
+
+        }
+
+        // contribute callee's writing effects to the caller
+        mergeSharedLocationAnaylsis(curr, possibleCalleeCompleteSummarySetToCaller);
+
+      }
+
+    }
+      break;
+
+    case FKind.FlatReturnNode: {
+      returnNodeSet.add(fn);
+    }
+      break;
+
+    }
+
+  }
+
+  private void updateWriteEffectOnReferenceField(ClearingSummary curr, NTuple<Descriptor> heapPath) {
+
+    // 2. if there exists a tuple t in sharing summary that starts with
+    // hp(x) then, set flag of tuple t to 'true'
+    Set<NTuple<Descriptor>> hpKeySet = curr.keySet();
+    for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+      if (hpKey.startsWith(heapPath)) {
+        curr.get(hpKey).updateFlag(true);
+      }
+    }
+
+  }
+
+  private ClearingSummary bindHeapPathOfCalleeCallerEffects(FlatCall fc,
+      FlatMethod calleeFlatMethod, ClearingSummary curr) {
+
+    ClearingSummary boundSet = new ClearingSummary();
+
+    // create mapping from arg idx to its heap paths
+    Hashtable<Integer, NTuple<Descriptor>> mapArgIdx2CallerArgHeapPath =
+        new Hashtable<Integer, NTuple<Descriptor>>();
+
+    if (fc.getThis() != null) {
+      // arg idx is starting from 'this' arg
+      NTuple<Descriptor> thisHeapPath = mapHeapPath.get(fc.getThis());
+      if (thisHeapPath == null) {
+        // method is called without creating new flat node representing 'this'
+        thisHeapPath = new NTuple<Descriptor>();
+        thisHeapPath.add(fc.getThis());
+      }
+
+      mapArgIdx2CallerArgHeapPath.put(Integer.valueOf(0), thisHeapPath);
+    }
+
+    for (int i = 0; i < fc.numArgs(); i++) {
+      TempDescriptor arg = fc.getArg(i);
+      NTuple<Descriptor> argHeapPath = computePath(arg);
+      mapArgIdx2CallerArgHeapPath.put(Integer.valueOf(i + 1), argHeapPath);
+    }
+
+    Hashtable<Integer, TempDescriptor> mapParamIdx2ParamTempDesc =
+        new Hashtable<Integer, TempDescriptor>();
+    int offset = 0;
+    if (calleeFlatMethod.getMethod().isStatic()) {
+      // static method does not have implicit 'this' arg
+      offset = 1;
+    }
+    for (int i = 0; i < calleeFlatMethod.numParameters(); i++) {
+      TempDescriptor param = calleeFlatMethod.getParameter(i);
+      mapParamIdx2ParamTempDesc.put(Integer.valueOf(i + offset), param);
+    }
+
+    // binding caller's writing effects to callee's params
+    for (int i = 0; i < calleeFlatMethod.numParameters(); i++) {
+      NTuple<Descriptor> argHeapPath = mapArgIdx2CallerArgHeapPath.get(Integer.valueOf(i));
+
+      if (argHeapPath != null) {
+        // if method is static, the first argument is nulll because static
+        // method does not have implicit "THIS" arg
+        TempDescriptor calleeParamHeapPath = mapParamIdx2ParamTempDesc.get(Integer.valueOf(i));
+
+        // iterate over caller's writing effect set
+        Set<NTuple<Descriptor>> hpKeySet = curr.keySet();
+        for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
+          NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+          // current element is reachable caller's arg
+          // so need to bind it to the caller's side and add it to the
+          // callee's
+          // init summary
+          if (hpKey.startsWith(argHeapPath)) {
+            NTuple<Descriptor> boundHeapPath = replace(hpKey, argHeapPath, calleeParamHeapPath);
+            boundSet.put(boundHeapPath, curr.get(hpKey).clone());
+          }
+
+        }
+      }
+
+    }
+
+    // contribute callee's complete summary into the caller's current summary
+    ClearingSummary calleeCompleteSummary =
+        mapMethodDescriptorToCompleteClearingSummary.get(calleeFlatMethod.getMethod());
+    if (calleeCompleteSummary != null) {
+      ClearingSummary boundCalleeEfffects = new ClearingSummary();
+      for (int i = 0; i < calleeFlatMethod.numParameters(); i++) {
+        NTuple<Descriptor> argHeapPath = mapArgIdx2CallerArgHeapPath.get(Integer.valueOf(i));
+
+        if (argHeapPath != null) {
+          // if method is static, the first argument is nulll because static
+          // method does not have implicit "THIS" arg
+          TempDescriptor calleeParamHeapPath = mapParamIdx2ParamTempDesc.get(Integer.valueOf(i));
+
+          // iterate over callee's writing effect set
+          Set<NTuple<Descriptor>> hpKeySet = calleeCompleteSummary.keySet();
+          for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
+            NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+            // current element is reachable caller's arg
+            // so need to bind it to the caller's side and add it to the
+            // callee's
+            // init summary
+            if (hpKey.startsWith(calleeParamHeapPath)) {
+
+              NTuple<Descriptor> boundHeapPathForCaller = replace(hpKey, argHeapPath);
+
+              boundCalleeEfffects.put(boundHeapPathForCaller, calleeCompleteSummary.get(hpKey)
+                  .clone());
+
+            }
+          }
+
+        }
+
+      }
+      possibleCalleeCompleteSummarySetToCaller.add(boundCalleeEfffects);
+    }
+
+    return boundSet;
+  }
+
+  private NTuple<Descriptor> replace(NTuple<Descriptor> hpKey, NTuple<Descriptor> argHeapPath) {
+
+    // replace the head of heap path with caller's arg path
+    // for example, heap path 'param.a.b' in callee's side will be replaced with
+    // (corresponding arg heap path).a.b for caller's side
+
+    NTuple<Descriptor> bound = new NTuple<Descriptor>();
+
+    for (int i = 0; i < argHeapPath.size(); i++) {
+      bound.add(argHeapPath.get(i));
+    }
+
+    for (int i = 1; i < hpKey.size(); i++) {
+      bound.add(hpKey.get(i));
+    }
+
+    return bound;
+  }
+
+  private NTuple<Descriptor> replace(NTuple<Descriptor> effectHeapPath,
+      NTuple<Descriptor> argHeapPath, TempDescriptor calleeParamHeapPath) {
+    // replace the head of caller's heap path with callee's param heap path
+
+    NTuple<Descriptor> boundHeapPath = new NTuple<Descriptor>();
+    boundHeapPath.add(calleeParamHeapPath);
+
+    for (int i = argHeapPath.size(); i < effectHeapPath.size(); i++) {
+      boundHeapPath.add(effectHeapPath.get(i));
+    }
+
+    return boundHeapPath;
+  }
+
+  private void computeSharedCoverSet() {
+    LinkedList<MethodDescriptor> descriptorListToAnalyze =
+        (LinkedList<MethodDescriptor>) sortedDescriptors.clone();
+
+    // current descriptors to visit in fixed-point interprocedural analysis,
+    // prioritized by
+    // dependency in the call graph
+    methodDescriptorsToVisitStack.clear();
+
+    descriptorListToAnalyze.removeFirst();
+
+    Set<MethodDescriptor> methodDescriptorToVistSet = new HashSet<MethodDescriptor>();
+    methodDescriptorToVistSet.addAll(descriptorListToAnalyze);
+
+    while (!descriptorListToAnalyze.isEmpty()) {
+      MethodDescriptor md = descriptorListToAnalyze.removeFirst();
+      methodDescriptorsToVisitStack.add(md);
+    }
+
+    // analyze scheduled methods until there are no more to visit
+    while (!methodDescriptorsToVisitStack.isEmpty()) {
+      MethodDescriptor md = methodDescriptorsToVisitStack.pop();
+      FlatMethod fm = state.getMethodFlat(md);
+      computeSharedCoverSet_analyzeMethod(fm, md.equals(methodContainingSSJavaLoop));
+    }
+
+    computeSharedCoverSetForEventLoop();
+
+  }
+
+  private void computeSharedCoverSetForEventLoop() {
+    computeSharedCoverSet_analyzeMethod(state.getMethodFlat(methodContainingSSJavaLoop), true);
+  }
+
+  private void computeSharedCoverSet_analyzeMethod(FlatMethod fm, boolean onlyVisitSSJavaLoop) {
+
+    MethodDescriptor md = fm.getMethod();
+    Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
+
+    Set<FlatNode> visited = new HashSet<FlatNode>();
+
+    if (onlyVisitSSJavaLoop) {
+      flatNodesToVisit.add(ssjavaLoopEntrance);
+    } else {
+      flatNodesToVisit.add(fm);
+    }
+
+    while (!flatNodesToVisit.isEmpty()) {
+      FlatNode fn = flatNodesToVisit.iterator().next();
+      flatNodesToVisit.remove(fn);
+      visited.add(fn);
+
+      computeSharedCoverSet_nodeActions(md, fn);
+
+      for (int i = 0; i < fn.numNext(); i++) {
+        FlatNode nn = fn.getNext(i);
+
+        if (!visited.contains(nn)) {
+          if (!onlyVisitSSJavaLoop || (onlyVisitSSJavaLoop && loopIncElements.contains(nn))) {
+            flatNodesToVisit.add(nn);
+          }
+        }
+
+      }
+
+    }
+
+  }
+
+  private void computeSharedCoverSet_nodeActions(MethodDescriptor md, FlatNode fn) {
+    TempDescriptor lhs;
+    TempDescriptor rhs;
+    FieldDescriptor fld;
+
+    switch (fn.kind()) {
+
+    case FKind.FlatLiteralNode: {
+      FlatLiteralNode fln = (FlatLiteralNode) fn;
+      lhs = fln.getDst();
+
+      if (lhs.getType().isPrimitive() && !lhs.getSymbol().startsWith("neverused")
+          && !lhs.getSymbol().startsWith("srctmp")) {
+        // only need to care about composite location case here
+        if (lhs.getType().getExtension() instanceof SSJavaType) {
+          CompositeLocation compLoc = ((SSJavaType) lhs.getType().getExtension()).getCompLoc();
+          Location lastLocElement = compLoc.get(compLoc.getSize() - 1);
+          // check if the last one is shared loc
+          if (ssjava.isSharedLocation(lastLocElement)) {
+            addSharedLocDescriptor(lastLocElement, lhs);
+          }
+        }
+      }
+
+    }
+      break;
+
+    case FKind.FlatOpNode: {
+      FlatOpNode fon = (FlatOpNode) fn;
+      // for a normal assign node, need to propagate lhs's location path to
+      // rhs
+      if (fon.getOp().getOp() == Operation.ASSIGN) {
+        rhs = fon.getLeft();
+        lhs = fon.getDest();
+
+        if (lhs.getType().isPrimitive() && !lhs.getSymbol().startsWith("neverused")
+            && !lhs.getSymbol().startsWith("srctmp") && !lhs.getSymbol().startsWith("leftop")
+            && !lhs.getSymbol().startsWith("rightop")) {
+
+          NTuple<Location> locTuple = deriveLocationTuple(md, rhs);
+          mapLocationPathToMayWrittenSet.put(locTuple, null, lhs);
+          addMayWrittenSet(md, locTuple, lhs);
 
-    while (!flatNodesToVisit.isEmpty()) {
-      FlatNode fn = flatNodesToVisit.iterator().next();
-      flatNodesToVisit.remove(fn);
+        }
 
-      String label = (String) state.fn2labelMap.get(fn);
-      if (label != null) {
+        if (mapDescriptorToLocationStrPath.containsKey(rhs)) {
+          mapDescriptorToLocationStrPath.put(lhs, mapDescriptorToLocationStrPath.get(rhs));
+        } else {
+          if (rhs.getType().getExtension() instanceof SSJavaType) {
+            NTuple<Location> locTuple =
+                ((SSJavaType) rhs.getType().getExtension()).getCompLoc().getTuple();
+            mapDescriptorToLocationStrPath.put(lhs, locTuple);
+          }
+        }
+
+      }
+    }
+      break;
+
+    case FKind.FlatSetFieldNode:
+    case FKind.FlatSetElementNode: {
+
+      // x.f=y;
+
+      if (fn.kind() == FKind.FlatSetFieldNode) {
+        FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
+        lhs = fsfn.getDst();
+        fld = fsfn.getField();
+        rhs = fsfn.getSrc();
+      } else {
+        FlatSetElementNode fsen = (FlatSetElementNode) fn;
+        lhs = fsen.getDst();
+        rhs = fsen.getSrc();
+        TypeDescriptor td = lhs.getType().dereference();
+        fld = getArrayField(td);
+      }
+
+      Location fieldLocation = (Location) fld.getType().getExtension();
+      if (ssjava.isSharedLocation(fieldLocation)) {
+        addSharedLocDescriptor(fieldLocation, fld);
+
+        System.out.println("FIELD WRITE FN=" + fn);
+        NTuple<Location> locTuple = deriveLocationTuple(md, lhs);
+        locTuple.addAll(deriveLocationTuple(md, fld));
+        System.out.println("LOC TUPLE=" + locTuple);
+
+        // mapLocationPathToMayWrittenSet.put(locTuple, null, fld);
+        addMayWrittenSet(md, locTuple, fld);
+      }
+
+    }
+      break;
+
+    case FKind.FlatElementNode:
+    case FKind.FlatFieldNode: {
+
+      // x=y.f;
+
+      if (fn.kind() == FKind.FlatFieldNode) {
+        FlatFieldNode ffn = (FlatFieldNode) fn;
+        lhs = ffn.getDst();
+        rhs = ffn.getSrc();
+        fld = ffn.getField();
+      } else {
+        FlatElementNode fen = (FlatElementNode) fn;
+        lhs = fen.getDst();
+        rhs = fen.getSrc();
+        TypeDescriptor td = rhs.getType().dereference();
+        fld = getArrayField(td);
+      }
+
+      if (fld.isFinal()) {
+        // if field is final no need to check
+        break;
+      }
+
+      NTuple<Location> locTuple = deriveLocationTuple(md, rhs);
+      locTuple.addAll(deriveLocationTuple(md, fld));
+      mapDescriptorToLocationStrPath.put(lhs, locTuple);
+
+    }
+      break;
+
+    case FKind.FlatCall: {
+
+      // System.out.println("###FLATCALL=" + fn);
+      FlatCall fc = (FlatCall) fn;
+      bindLocationPathCallerArgWithCalleeParam(md, fc);
+
+    }
+      break;
+
+    }
+  }
+
+  private void addMayWrittenSet(MethodDescriptor md, NTuple<Location> locTuple, Descriptor d) {
+
+    MultiSourceMap<Location, Descriptor> map = mapMethodToSharedWriteMapping.get(md);
+    if (map == null) {
+      map = new MultiSourceMap<Location, Descriptor>();
+      mapMethodToSharedWriteMapping.put(md, map);
+    }
+
+    Set<Descriptor> writeSet = map.get(locTuple);
+    if (writeSet == null) {
+      writeSet = new HashSet<Descriptor>();
+      map.put(locTuple, writeSet);
+    }
+    writeSet.add(d);
+
+    System.out.println("ADD WRITE DESC=" + d + " TO locTuple=" + locTuple);
+  }
+
+  private void bindLocationPathCallerArgWithCalleeParam(MethodDescriptor mdCaller, FlatCall fc) {
+
+    if (ssjava.isSSJavaUtil(fc.getMethod().getClassDesc())) {
+      // ssjava util case!
+      // have write effects on the first argument
+      TempDescriptor arg = fc.getArg(0);
+      NTuple<Location> argLocationPath = deriveLocationTuple(mdCaller, arg);
+      NTuple<Descriptor> argHeapPath = computePath(arg);
+      mapLocationPathToMayWrittenSet.put(argLocationPath, null,
+          argHeapPath.get(argHeapPath.size() - 1));
+
+    } else {
+
+      // if arg is not primitive type, we need to propagate maywritten set to
+      // the caller's location path
+
+      MethodDescriptor mdCallee = fc.getMethod();
+      Set<MethodDescriptor> setPossibleCallees = new HashSet<MethodDescriptor>();
+      setPossibleCallees.addAll(callGraph.getMethods(mdCallee));
+
+      // create mapping from arg idx to its heap paths
+      Hashtable<Integer, NTuple<Location>> mapArgIdx2CallerAgLocationStrPath =
+          new Hashtable<Integer, NTuple<Location>>();
+
+      // arg idx is starting from 'this' arg
+      if (fc.getThis() != null) {
+        NTuple<Location> thisLocationPath = deriveLocationTuple(mdCaller, fc.getThis());
+        mapArgIdx2CallerAgLocationStrPath.put(Integer.valueOf(0), thisLocationPath);
+      }
+
+      Hashtable<Integer, Set<Descriptor>> mapParamIdx2WriteSet =
+          new Hashtable<Integer, Set<Descriptor>>();
+
+      for (int i = 0; i < fc.numArgs() + 1; i++) {
+        mapParamIdx2WriteSet.put(Integer.valueOf(i), new HashSet<Descriptor>());
+      }
+
+      for (int i = 0; i < fc.numArgs(); i++) {
+        TempDescriptor arg = fc.getArg(i);
+        NTuple<Location> argLocationPath = deriveLocationTuple(mdCaller, arg);
+        mapArgIdx2CallerAgLocationStrPath.put(Integer.valueOf(i + 1), argLocationPath);
+      }
+
+      for (Iterator iterator = setPossibleCallees.iterator(); iterator.hasNext();) {
+        MethodDescriptor callee = (MethodDescriptor) iterator.next();
+        FlatMethod calleeFlatMethod = state.getMethodFlat(callee);
+
+        // binding caller's args and callee's params
+
+        Hashtable<Integer, TempDescriptor> mapParamIdx2ParamTempDesc =
+            new Hashtable<Integer, TempDescriptor>();
+        int offset = 0;
+        if (calleeFlatMethod.getMethod().isStatic()) {
+          // static method does not have implicit 'this' arg
+          offset = 1;
+        }
+        for (int i = 0; i < calleeFlatMethod.numParameters(); i++) {
+          TempDescriptor param = calleeFlatMethod.getParameter(i);
+          mapParamIdx2ParamTempDesc.put(Integer.valueOf(i + offset), param);
+        }
+
+        Set<Integer> keySet = mapArgIdx2CallerAgLocationStrPath.keySet();
+        for (Iterator iterator2 = keySet.iterator(); iterator2.hasNext();) {
+          Integer idx = (Integer) iterator2.next();
+          NTuple<Location> callerArgLocationStrPath = mapArgIdx2CallerAgLocationStrPath.get(idx);
+
+          TempDescriptor calleeParam = mapParamIdx2ParamTempDesc.get(idx);
+          NTuple<Location> calleeLocationPath = deriveLocationTuple(mdCallee, calleeParam);
+
+          // System.out.println("#createNewMappingOfMayWrittenSet callee=" +
+          // callee
+          // + " callerArgLocationStrPath=" + callerArgLocationStrPath +
+          // "calleeLocationPath="
+          // + calleeLocationPath + " idx=" + idx + " writeset=" +
+          // mapParamIdx2WriteSet.get(idx));
+          createNewMappingOfMayWrittenSet(callee, callerArgLocationStrPath, calleeLocationPath,
+              mapParamIdx2WriteSet.get(idx));
 
-        if (label.equals(ssjava.SSJAVA)) {
-          ssjavaLoopEntrance = fn;
-          break;
         }
+
       }
 
-      for (int i = 0; i < fn.numNext(); i++) {
-        FlatNode nn = fn.getNext(i);
-        flatNodesToVisit.add(nn);
+    }
+
+  }
+
+  private void createNewMappingOfMayWrittenSet(MethodDescriptor callee,
+      NTuple<Location> callerPath, NTuple<Location> calleeParamPath, Set<Descriptor> writeSet) {
+
+    // propagate may-written-set associated with the key that is started with
+    // calleepath to the caller
+    // 1) makes a new key by combining caller path and callee path(except local
+    // loc element of param)
+    // 2) create new mapping of may-written-set of callee path to caller path
+
+    // extract all may written effect accessed through callee param path
+    MultiSourceMap<Location, Descriptor> mapping = mapMethodToSharedWriteMapping.get(callee);
+
+    if (mapping == null) {
+      return;
+    }
+
+    Hashtable<NTuple<Location>, Set<Descriptor>> paramMapping =
+        mapping.getMappingByStartedWith(calleeParamPath);
+
+    Set<NTuple<Location>> calleeKeySet = mapping.keySet();
+    for (Iterator iterator = calleeKeySet.iterator(); iterator.hasNext();) {
+      NTuple<Location> calleeKey = (NTuple<Location>) iterator.next();
+      Set<Descriptor> calleeMayWriteSet = paramMapping.get(calleeKey);
+
+      if (calleeMayWriteSet != null) {
+        writeSet.addAll(calleeMayWriteSet);
+
+        NTuple<Location> newKey = new NTuple<Location>();
+        newKey.addAll(callerPath);
+        // need to replace the local location with the caller's path so skip the
+        // local location of the parameter
+        for (int i = 1; i < calleeKey.size(); i++) {
+          newKey.add(calleeKey.get(i));
+        }
+
+        System.out.println("calleeParamPath=" + calleeParamPath + " newKey=" + newKey
+            + " maywriteSet=" + writeSet);
+        mapLocationPathToMayWrittenSet.put(calleeKey, newKey, writeSet);
       }
+
     }
 
-    assert ssjavaLoopEntrance != null;
+  }
 
-    // assume that ssjava loop is top-level loop in method, not nested loop
-    Set nestedLoop = loopFinder.nestedLoops();
-    for (Iterator loopIter = nestedLoop.iterator(); loopIter.hasNext();) {
-      LoopFinder lf = (LoopFinder) loopIter.next();
-      if (lf.loopEntrances().iterator().next().equals(ssjavaLoopEntrance)) {
-        ssjavaLoop = lf;
+  private void addSharedLocDescriptor(Location sharedLoc, Descriptor desc) {
+
+    Set<Descriptor> descSet = mapSharedLocationToCoverSet.get(sharedLoc);
+    if (descSet == null) {
+      descSet = new HashSet<Descriptor>();
+      mapSharedLocationToCoverSet.put(sharedLoc, descSet);
+    }
+
+    descSet.add(desc);
+
+  }
+
+  private boolean hasReadingEffectOnSharedLocation(MethodDescriptor md, NTuple<Descriptor> hp,
+      Location loc, Descriptor d) {
+
+    ReadSummary summary = mapMethodDescriptorToReadSummary.get(md);
+
+    if (summary != null) {
+      Hashtable<Location, Set<Descriptor>> map = summary.get(hp);
+      if (map != null) {
+        Set<Descriptor> descSec = map.get(loc);
+        if (descSec != null) {
+          return descSec.contains(d);
+        }
       }
     }
+    return false;
 
-    assert ssjavaLoop != null;
+  }
+
+  private Location getLocation(Descriptor d) {
+
+    System.out.println("GETLOCATION d=" + d + " d=" + d.getClass());
+
+    if (d instanceof FieldDescriptor) {
+      TypeExtension te = ((FieldDescriptor) d).getType().getExtension();
+      if (te != null) {
+        return (Location) te;
+      }
+    } else {
+      assert d instanceof TempDescriptor;
+      TempDescriptor td = (TempDescriptor) d;
+
+      TypeExtension te = td.getType().getExtension();
+      if (te != null) {
+        if (te instanceof SSJavaType) {
+          SSJavaType ssType = (SSJavaType) te;
+          CompositeLocation comp = ssType.getCompLoc();
+          return comp.get(comp.getSize() - 1);
+        } else {
+          return (Location) te;
+        }
+      }
+    }
+
+    return mapDescToLocation.get(d);
+  }
+
+  private void writeLocation(MethodDescriptor md, ClearingSummary curr, NTuple<Descriptor> hp,
+      Location loc, Descriptor d) {
+
+    SharedStatus state = getState(curr, hp);
+    if (loc != null && hasReadingEffectOnSharedLocation(md, hp, loc, d)) {
+      // 1. add field x to the clearing set
+
+      state.addVar(loc, d);
+
+      // 3. if the set v contains all of variables belonging to the shared
+      // location, set flag to true
+      if (isOverWrittenAllDescsOfSharedLoc(md, hp, loc, state.getVarSet(loc))) {
+        state.updateFlag(loc, true);
+      }
+    }
+    state.setWriteEffect(loc);
+
+  }
+
+  private boolean isOverWrittenAllDescsOfSharedLoc(MethodDescriptor md, NTuple<Descriptor> hp,
+      Location loc, Set<Descriptor> writtenSet) {
+
+    ReadSummary summary = mapMethodDescriptorToReadSummary.get(md);
+
+    if (summary != null) {
+      Hashtable<Location, Set<Descriptor>> map = summary.get(hp);
+      if (map != null) {
+        Set<Descriptor> descSet = map.get(loc);
+        if (descSet != null) {
+          return writtenSet.containsAll(descSet);
+        }
+      }
+    }
+    return false;
+  }
 
-    writtenAnalysis_analyzeLoop();
+  private void readLocation(MethodDescriptor md, ClearingSummary curr, NTuple<Descriptor> hp,
+      Location loc, Descriptor d) {
+    // remove reading var x from written set
+    if (loc != null && hasReadingEffectOnSharedLocation(md, hp, loc, d)) {
+      SharedStatus state = getState(curr, hp);
+      state.removeVar(loc, d);
+    }
+  }
 
+  private SharedStatus getState(ClearingSummary curr, NTuple<Descriptor> hp) {
+    SharedStatus state = curr.get(hp);
+    if (state == null) {
+      state = new SharedStatus();
+      curr.put(hp, state);
+    }
+    return state;
   }
 
-  private void writtenAnalysis_analyzeLoop() {
+  private void eventLoopAnalysis() {
+    // perform second stage analysis: intraprocedural analysis ensure that
+    // all
+    // variables are definitely written in-between the same read
 
     Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
     flatNodesToVisit.add(ssjavaLoopEntrance);
 
-    loopIncElements = (Set<FlatNode>) ssjavaLoop.loopIncElements();
-
     while (!flatNodesToVisit.isEmpty()) {
       FlatNode fn = (FlatNode) flatNodesToVisit.iterator().next();
       flatNodesToVisit.remove(fn);
 
-      Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> prev =
-          definitelyWrittenResults.get(fn);
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> prev = mapFlatNodetoEventLoopMap.get(fn);
 
-      Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> curr =
-          new Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>>();
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> curr =
+          new Hashtable<NTuple<Descriptor>, Set<WriteAge>>();
       for (int i = 0; i < fn.numPrev(); i++) {
         FlatNode nn = fn.getPrev(i);
-        Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> dwIn =
-            definitelyWrittenResults.get(nn);
-        if (dwIn != null) {
-          merge(curr, dwIn);
+        Hashtable<NTuple<Descriptor>, Set<WriteAge>> in = mapFlatNodetoEventLoopMap.get(nn);
+        if (in != null) {
+          union(curr, in);
         }
       }
 
-      writtenAnalysis_nodeAction(fn, curr, ssjavaLoopEntrance);
+      eventLoopAnalysis_nodeAction(fn, curr, ssjavaLoopEntrance);
 
       // if a new result, schedule forward nodes for analysis
       if (!curr.equals(prev)) {
-        definitelyWrittenResults.put(fn, curr);
+        mapFlatNodetoEventLoopMap.put(fn, curr);
 
         for (int i = 0; i < fn.numNext(); i++) {
           FlatNode nn = fn.getNext(i);
@@ -612,56 +1587,87 @@ public class DefinitelyWrittenCheck {
     }
   }
 
-  private void writtenAnalysis_nodeAction(FlatNode fn,
-      Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> curr, FlatNode loopEntrance) {
+  private void union(Hashtable<NTuple<Descriptor>, Set<WriteAge>> curr,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> in) {
+
+    Set<NTuple<Descriptor>> inKeySet = in.keySet();
+    for (Iterator iterator = inKeySet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> inKey = (NTuple<Descriptor>) iterator.next();
+      Set<WriteAge> inSet = in.get(inKey);
+
+      Set<WriteAge> currSet = curr.get(inKey);
+
+      if (currSet == null) {
+        currSet = new HashSet<WriteAge>();
+        curr.put(inKey, currSet);
+      }
+      currSet.addAll(inSet);
+    }
+
+  }
+
+  private void eventLoopAnalysis_nodeAction(FlatNode fn,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> curr, FlatNode loopEntrance) {
+
+    Hashtable<NTuple<Descriptor>, Set<WriteAge>> readWriteKillSet =
+        new Hashtable<NTuple<Descriptor>, Set<WriteAge>>();
+    Hashtable<NTuple<Descriptor>, Set<WriteAge>> readWriteGenSet =
+        new Hashtable<NTuple<Descriptor>, Set<WriteAge>>();
 
     if (fn.equals(loopEntrance)) {
       // it reaches loop entrance: changes all flag to true
       Set<NTuple<Descriptor>> keySet = curr.keySet();
       for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
         NTuple<Descriptor> key = (NTuple<Descriptor>) iterator.next();
-        Hashtable<FlatNode, Boolean> pair = curr.get(key);
-        if (pair != null) {
-          Set<FlatNode> pairKeySet = pair.keySet();
-          for (Iterator iterator2 = pairKeySet.iterator(); iterator2.hasNext();) {
-            FlatNode pairKey = (FlatNode) iterator2.next();
-            pair.put(pairKey, Boolean.TRUE);
-          }
+        Set<WriteAge> writeAgeSet = curr.get(key);
+
+        Set<WriteAge> incSet = new HashSet<WriteAge>();
+        incSet.addAll(writeAgeSet);
+        writeAgeSet.clear();
+
+        for (Iterator iterator2 = incSet.iterator(); iterator2.hasNext();) {
+          WriteAge writeAge = (WriteAge) iterator2.next();
+          WriteAge newWriteAge = writeAge.copy();
+          newWriteAge.inc();
+          writeAgeSet.add(newWriteAge);
         }
+
       }
+      // System.out.println("EVENT LOOP ENTRY=" + curr);
+
     } else {
       TempDescriptor lhs;
       TempDescriptor rhs;
       FieldDescriptor fld;
 
       switch (fn.kind()) {
+
       case FKind.FlatOpNode: {
         FlatOpNode fon = (FlatOpNode) fn;
         lhs = fon.getDest();
         rhs = fon.getLeft();
 
-        NTuple<Descriptor> rhsHeapPath = computePath(rhs);
-        if (!rhs.getType().isImmutable()) {
-          mapHeapPath.put(lhs, rhsHeapPath);
-        } else {
-          if (fon.getOp().getOp() == Operation.ASSIGN) {
-            // read(rhs)
-            readValue(fn, rhsHeapPath, curr);
-          }
-          // write(lhs)
-          NTuple<Descriptor> lhsHeapPath = computePath(lhs);
-          removeHeapPath(curr, lhsHeapPath);
-        }
-      }
-        break;
+        if (!lhs.getSymbol().startsWith("neverused")) {
+          NTuple<Descriptor> rhsHeapPath = computePath(rhs);
+          if (!rhs.getType().isImmutable()) {
+            mapHeapPath.put(lhs, rhsHeapPath);
+          } else {
+            // write(lhs)
+            // NTuple<Descriptor> lhsHeapPath = computePath(lhs);
+            NTuple<Descriptor> path = new NTuple<Descriptor>();
+            path.add(lhs);
 
-      case FKind.FlatLiteralNode: {
-        FlatLiteralNode fln = (FlatLiteralNode) fn;
-        lhs = fln.getDst();
+            // System.out.println("WRITE VARIABLE=" + path + " from=" + lhs);
 
-        // write(lhs)
-        NTuple<Descriptor> lhsHeapPath = computePath(lhs);
-        removeHeapPath(curr, lhsHeapPath);
+            computeKILLSetForWrite(curr, path, readWriteKillSet);
+            computeGENSetForWrite(path, readWriteGenSet);
+
+            // System.out.println("#VARIABLE WRITE:" + fn);
+            // System.out.println("#KILLSET=" + KILLSet);
+            // System.out.println("#GENSet=" + GENSet);
+
+          }
+        }
 
       }
         break;
@@ -669,22 +1675,33 @@ public class DefinitelyWrittenCheck {
       case FKind.FlatFieldNode:
       case FKind.FlatElementNode: {
 
-        FlatFieldNode ffn = (FlatFieldNode) fn;
-        lhs = ffn.getDst();
-        rhs = ffn.getSrc();
-        fld = ffn.getField();
+        if (fn.kind() == FKind.FlatFieldNode) {
+          FlatFieldNode ffn = (FlatFieldNode) fn;
+          lhs = ffn.getDst();
+          rhs = ffn.getSrc();
+          fld = ffn.getField();
+        } else {
+          FlatElementNode fen = (FlatElementNode) fn;
+          lhs = fen.getDst();
+          rhs = fen.getSrc();
+          TypeDescriptor td = rhs.getType().dereference();
+          fld = getArrayField(td);
+        }
 
         // read field
         NTuple<Descriptor> srcHeapPath = mapHeapPath.get(rhs);
-        NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(srcHeapPath.getList());
-        fldHeapPath.add(fld);
-
-        if (fld.getType().isImmutable()) {
-          readValue(fn, fldHeapPath, curr);
+        NTuple<Descriptor> fldHeapPath;
+        if (srcHeapPath != null) {
+          fldHeapPath = new NTuple<Descriptor>(srcHeapPath.getList());
+        } else {
+          // if srcHeapPath is null, it is static reference
+          fldHeapPath = new NTuple<Descriptor>();
+          fldHeapPath.add(rhs);
         }
+        fldHeapPath.add(fld);
 
-        // propagate rhs's heap path to the lhs
-        mapHeapPath.put(lhs, fldHeapPath);
+        Set<WriteAge> writeAgeSet = curr.get(fldHeapPath);
+        checkWriteAgeSet(writeAgeSet, fldHeapPath, fn);
 
       }
         break;
@@ -692,57 +1709,140 @@ public class DefinitelyWrittenCheck {
       case FKind.FlatSetFieldNode:
       case FKind.FlatSetElementNode: {
 
-        FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
-        lhs = fsfn.getDst();
-        fld = fsfn.getField();
+        if (fn.kind() == FKind.FlatSetFieldNode) {
+          FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
+          lhs = fsfn.getDst();
+          fld = fsfn.getField();
+        } else {
+          FlatSetElementNode fsen = (FlatSetElementNode) fn;
+          lhs = fsen.getDst();
+          rhs = fsen.getSrc();
+          TypeDescriptor td = lhs.getType().dereference();
+          fld = getArrayField(td);
+        }
 
         // write(field)
         NTuple<Descriptor> lhsHeapPath = computePath(lhs);
         NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
         fldHeapPath.add(fld);
-        removeHeapPath(curr, fldHeapPath);
+
+        computeKILLSetForWrite(curr, fldHeapPath, readWriteKillSet);
+        computeGENSetForWrite(fldHeapPath, readWriteGenSet);
+
+        // System.out.println("FIELD WRITE:" + fn);
+        // System.out.println("KILLSET=" + KILLSet);
+        // System.out.println("GENSet=" + GENSet);
 
       }
         break;
 
       case FKind.FlatCall: {
         FlatCall fc = (FlatCall) fn;
-        bindHeapPathCallerArgWithCaleeParam(fc);
-
-        // add <hp,statement,false> in which hp is an element of
-        // READ_bound set
-        // of callee: callee has 'read' requirement!
-        for (Iterator iterator = calleeUnionBoundReadSet.iterator(); iterator.hasNext();) {
-          NTuple<Descriptor> read = (NTuple<Descriptor>) iterator.next();
-
-          Hashtable<FlatNode, Boolean> gen = curr.get(read);
-          if (gen == null) {
-            gen = new Hashtable<FlatNode, Boolean>();
-            curr.put(read, gen);
-          }
-          Boolean currentStatus = gen.get(fn);
-          if (currentStatus == null) {
-            gen.put(fn, Boolean.FALSE);
-          } else {
-            checkFlag(currentStatus.booleanValue(), fn, read);
-          }
+
+        generateKILLSetForFlatCall(fc, curr, readWriteKillSet);
+        generateGENSetForFlatCall(fc, readWriteGenSet);
+
+        // System.out.println("FLATCALL:" + fn);
+        // System.out.println("KILLSET=" + KILLSet);
+        // System.out.println("GENSet=" + GENSet);
+
+      }
+        break;
+
+      }
+
+      computeNewMapping(curr, readWriteKillSet, readWriteGenSet);
+      // System.out.println("#######" + curr);
+
+    }
+
+  }
+
+  private void checkWriteAgeSet(Set<WriteAge> writeAgeSet, NTuple<Descriptor> path, FlatNode fn) {
+    if (writeAgeSet != null) {
+      for (Iterator iterator = writeAgeSet.iterator(); iterator.hasNext();) {
+        WriteAge writeAge = (WriteAge) iterator.next();
+        if (writeAge.getAge() >= MAXAGE) {
+          throw new Error(
+              "Memory location, which is reachable through references "
+                  + path
+                  + ", who comes back to the same read statement without being overwritten at the out-most iteration at "
+                  + methodContainingSSJavaLoop.getClassDesc().getSourceFileName() + "::"
+                  + fn.getNumLine());
         }
+      }
+    }
+  }
+
+  private void generateGENSetForFlatCall(FlatCall fc,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> GENSet) {
+
+    Set<NTuple<Descriptor>> boundMayWriteSet = mapFlatNodeToBoundMayWriteSet.get(fc);
+
+    for (Iterator iterator = boundMayWriteSet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> key = (NTuple<Descriptor>) iterator.next();
+      // TODO: shared location
+      Set<WriteAge> set = new HashSet<WriteAge>();
+      set.add(new WriteAge(0));
+      GENSet.put(key, set);
+    }
+
+  }
+
+  private void generateKILLSetForFlatCall(FlatCall fc,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> curr,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> KILLSet) {
+
+    Set<NTuple<Descriptor>> boundMustWriteSet = mapFlatNodeToBoundMustWriteSet.get(fc);
+
+    for (Iterator iterator = boundMustWriteSet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> key = (NTuple<Descriptor>) iterator.next();
+      // TODO: shared location
+      if (curr.get(key) != null) {
+        KILLSet.put(key, curr.get(key));
+      }
+    }
+
+  }
+
+  private void computeNewMapping(SharedLocMappingSet curr, SharedLocMappingSet KILLSet,
+      SharedLocMappingSet GENSet) {
+    curr.kill(KILLSet);
+    curr.add(GENSet);
+  }
 
-        // removes <hp,statement,flag> if hp is an element of
-        // OVERWRITE_bound
-        // set of callee. it means that callee will overwrite it
-        for (Iterator iterator = calleeIntersectBoundOverWriteSet.iterator(); iterator.hasNext();) {
-          NTuple<Descriptor> write = (NTuple<Descriptor>) iterator.next();
-          removeHeapPath(curr, write);
-        }
-      }
-        break;
+  private void computeNewMapping(Hashtable<NTuple<Descriptor>, Set<WriteAge>> curr,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> KILLSet,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> GENSet) {
 
+    for (Enumeration<NTuple<Descriptor>> e = KILLSet.keys(); e.hasMoreElements();) {
+      NTuple<Descriptor> key = e.nextElement();
+
+      Set<WriteAge> writeAgeSet = curr.get(key);
+      if (writeAgeSet == null) {
+        writeAgeSet = new HashSet<WriteAge>();
+        curr.put(key, writeAgeSet);
       }
+      writeAgeSet.removeAll(KILLSet.get(key));
+    }
+
+    for (Enumeration<NTuple<Descriptor>> e = GENSet.keys(); e.hasMoreElements();) {
+      NTuple<Descriptor> key = e.nextElement();
+      curr.put(key, GENSet.get(key));
     }
 
   }
 
+  private void computeGENSetForWrite(NTuple<Descriptor> fldHeapPath,
+      Hashtable<NTuple<Descriptor>, Set<WriteAge>> GENSet) {
+
+    // generate write age 0 for the field being written to
+    Set<WriteAge> writeAgeSet = new HashSet<WriteAge>();
+    writeAgeSet.add(new WriteAge(0));
+    GENSet.put(fldHeapPath, writeAgeSet);
+
+  }
+
   private void readValue(FlatNode fn, NTuple<Descriptor> hp,
       Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> curr) {
     Hashtable<FlatNode, Boolean> gen = curr.get(hp);
@@ -759,8 +1859,8 @@ public class DefinitelyWrittenCheck {
 
   }
 
-  private void removeHeapPath(Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> curr,
-      NTuple<Descriptor> hp) {
+  private void computeKILLSetForWrite(Hashtable<NTuple<Descriptor>, Set<WriteAge>> curr,
+      NTuple<Descriptor> hp, Hashtable<NTuple<Descriptor>, Set<WriteAge>> KILLSet) {
 
     // removes all of heap path that starts with prefix 'hp'
     // since any reference overwrite along heap path gives overwriting side
@@ -770,40 +1870,142 @@ public class DefinitelyWrittenCheck {
     for (Iterator<NTuple<Descriptor>> iter = keySet.iterator(); iter.hasNext();) {
       NTuple<Descriptor> key = iter.next();
       if (key.startsWith(hp)) {
-        curr.put(key, new Hashtable<FlatNode, Boolean>());
+        KILLSet.put(key, curr.get(key));
       }
     }
 
   }
 
-  private void bindHeapPathCallerArgWithCaleeParam(FlatCall fc) {
+  private void bindHeapPathCallerArgWithCalleeParam(FlatCall fc) {
     // compute all possible callee set
-    // transform all READ/OVERWRITE set from the any possible
-    // callees to the
-    // caller
-
+    // transform all READ/WRITE set from the any possible
+    // callees to the caller
     calleeUnionBoundReadSet.clear();
-    calleeIntersectBoundOverWriteSet.clear();
+    calleeIntersectBoundMustWriteSet.clear();
+    calleeUnionBoundMayWriteSet.clear();
+
+    if (ssjava.isSSJavaUtil(fc.getMethod().getClassDesc())) {
+      // ssjava util case!
+      // have write effects on the first argument
+      TempDescriptor arg = fc.getArg(0);
+      NTuple<Descriptor> argHeapPath = computePath(arg);
+      calleeIntersectBoundMustWriteSet.add(argHeapPath);
+      calleeUnionBoundMayWriteSet.add(argHeapPath);
+    } else {
+      MethodDescriptor mdCallee = fc.getMethod();
+      Set<MethodDescriptor> setPossibleCallees = new HashSet<MethodDescriptor>();
+      setPossibleCallees.addAll(callGraph.getMethods(mdCallee));
+
+      // create mapping from arg idx to its heap paths
+      Hashtable<Integer, NTuple<Descriptor>> mapArgIdx2CallerArgHeapPath =
+          new Hashtable<Integer, NTuple<Descriptor>>();
+
+      // arg idx is starting from 'this' arg
+      if (fc.getThis() != null) {
+        NTuple<Descriptor> thisHeapPath = mapHeapPath.get(fc.getThis());
+        if (thisHeapPath == null) {
+          // method is called without creating new flat node representing 'this'
+          thisHeapPath = new NTuple<Descriptor>();
+          thisHeapPath.add(fc.getThis());
+        }
+
+        mapArgIdx2CallerArgHeapPath.put(Integer.valueOf(0), thisHeapPath);
+      }
+
+      for (int i = 0; i < fc.numArgs(); i++) {
+        TempDescriptor arg = fc.getArg(i);
+        NTuple<Descriptor> argHeapPath = computePath(arg);
+        mapArgIdx2CallerArgHeapPath.put(Integer.valueOf(i + 1), argHeapPath);
+      }
+
+      for (Iterator iterator = setPossibleCallees.iterator(); iterator.hasNext();) {
+        MethodDescriptor callee = (MethodDescriptor) iterator.next();
+        FlatMethod calleeFlatMethod = state.getMethodFlat(callee);
+
+        // binding caller's args and callee's params
+
+        Set<NTuple<Descriptor>> calleeReadSet = mapFlatMethodToReadSet.get(calleeFlatMethod);
+        if (calleeReadSet == null) {
+          calleeReadSet = new HashSet<NTuple<Descriptor>>();
+          mapFlatMethodToReadSet.put(calleeFlatMethod, calleeReadSet);
+        }
+
+        Set<NTuple<Descriptor>> calleeMustWriteSet =
+            mapFlatMethodToMustWriteSet.get(calleeFlatMethod);
+
+        if (calleeMustWriteSet == null) {
+          calleeMustWriteSet = new HashSet<NTuple<Descriptor>>();
+          mapFlatMethodToMustWriteSet.put(calleeFlatMethod, calleeMustWriteSet);
+        }
+
+        Set<NTuple<Descriptor>> calleeMayWriteSet =
+            mapFlatMethodToMayWriteSet.get(calleeFlatMethod);
+
+        if (calleeMayWriteSet == null) {
+          calleeMayWriteSet = new HashSet<NTuple<Descriptor>>();
+          mapFlatMethodToMayWriteSet.put(calleeFlatMethod, calleeMayWriteSet);
+        }
+
+        Hashtable<Integer, TempDescriptor> mapParamIdx2ParamTempDesc =
+            new Hashtable<Integer, TempDescriptor>();
+        int offset = 0;
+        if (calleeFlatMethod.getMethod().isStatic()) {
+          // static method does not have implicit 'this' arg
+          offset = 1;
+        }
+        for (int i = 0; i < calleeFlatMethod.numParameters(); i++) {
+          TempDescriptor param = calleeFlatMethod.getParameter(i);
+          mapParamIdx2ParamTempDesc.put(Integer.valueOf(i + offset), param);
+        }
+
+        Set<NTuple<Descriptor>> calleeBoundReadSet =
+            bindSet(calleeReadSet, mapParamIdx2ParamTempDesc, mapArgIdx2CallerArgHeapPath);
+        // union of the current read set and the current callee's
+        // read set
+        calleeUnionBoundReadSet.addAll(calleeBoundReadSet);
+
+        Set<NTuple<Descriptor>> calleeBoundMustWriteSet =
+            bindSet(calleeMustWriteSet, mapParamIdx2ParamTempDesc, mapArgIdx2CallerArgHeapPath);
+        // intersection of the current overwrite set and the current
+        // callee's
+        // overwrite set
+        merge(calleeIntersectBoundMustWriteSet, calleeBoundMustWriteSet);
+
+        Set<NTuple<Descriptor>> boundWriteSetFromCallee =
+            bindSet(calleeMayWriteSet, mapParamIdx2ParamTempDesc, mapArgIdx2CallerArgHeapPath);
+        calleeUnionBoundMayWriteSet.addAll(boundWriteSetFromCallee);
+      }
+
+    }
+
+  }
+
+  private void bindHeapPathCallerArgWithCaleeParamForSharedLoc(FlatCall fc) {
+    // compute all possible callee set
+    // transform all DELETE set from the any possible
+    // callees to the caller
+    calleeUnionBoundDeleteSet.clear();
+    calleeIntersectBoundSharedSet.clear();
 
     MethodDescriptor mdCallee = fc.getMethod();
-    FlatMethod fmCallee = state.getMethodFlat(mdCallee);
     Set<MethodDescriptor> setPossibleCallees = new HashSet<MethodDescriptor>();
-    TypeDescriptor typeDesc = fc.getThis().getType();
-    setPossibleCallees.addAll(callGraph.getMethods(mdCallee, typeDesc));
+    setPossibleCallees.addAll(callGraph.getMethods(mdCallee));
 
     // create mapping from arg idx to its heap paths
     Hashtable<Integer, NTuple<Descriptor>> mapArgIdx2CallerArgHeapPath =
         new Hashtable<Integer, NTuple<Descriptor>>();
 
     // arg idx is starting from 'this' arg
-    NTuple<Descriptor> thisHeapPath = mapHeapPath.get(fc.getThis());
-    if (thisHeapPath == null) {
-      // method is called without creating new flat node representing 'this'
-      thisHeapPath = new NTuple<Descriptor>();
-      thisHeapPath.add(fc.getThis());
-    }
+    if (fc.getThis() != null) {
+      NTuple<Descriptor> thisHeapPath = mapHeapPath.get(fc.getThis());
+      if (thisHeapPath == null) {
+        // method is called without creating new flat node representing 'this'
+        thisHeapPath = new NTuple<Descriptor>();
+        thisHeapPath.add(fc.getThis());
+      }
 
-    mapArgIdx2CallerArgHeapPath.put(Integer.valueOf(0), thisHeapPath);
+      mapArgIdx2CallerArgHeapPath.put(Integer.valueOf(0), thisHeapPath);
+    }
 
     for (int i = 0; i < fc.numArgs(); i++) {
       TempDescriptor arg = fc.getArg(i);
@@ -817,102 +2019,168 @@ public class DefinitelyWrittenCheck {
 
       // binding caller's args and callee's params
 
-      Set<NTuple<Descriptor>> calleeReadSet = mapFlatMethodToRead.get(calleeFlatMethod);
+      Set<NTuple<Descriptor>> calleeReadSet = mapFlatMethodToDeleteSet.get(calleeFlatMethod);
       if (calleeReadSet == null) {
         calleeReadSet = new HashSet<NTuple<Descriptor>>();
-        mapFlatMethodToRead.put(calleeFlatMethod, calleeReadSet);
-      }
-      Set<NTuple<Descriptor>> calleeOverWriteSet = mapFlatMethodToOverWrite.get(calleeFlatMethod);
-      if (calleeOverWriteSet == null) {
-        calleeOverWriteSet = new HashSet<NTuple<Descriptor>>();
-        mapFlatMethodToOverWrite.put(calleeFlatMethod, calleeOverWriteSet);
+        mapFlatMethodToDeleteSet.put(calleeFlatMethod, calleeReadSet);
       }
 
       Hashtable<Integer, TempDescriptor> mapParamIdx2ParamTempDesc =
           new Hashtable<Integer, TempDescriptor>();
+      int offset = 0;
+      if (calleeFlatMethod.getMethod().isStatic()) {
+        // static method does not have implicit 'this' arg
+        offset = 1;
+      }
       for (int i = 0; i < calleeFlatMethod.numParameters(); i++) {
         TempDescriptor param = calleeFlatMethod.getParameter(i);
-        mapParamIdx2ParamTempDesc.put(Integer.valueOf(i), param);
+        mapParamIdx2ParamTempDesc.put(Integer.valueOf(i + offset), param);
       }
 
-      Set<NTuple<Descriptor>> calleeBoundReadSet =
+      Set<NTuple<Descriptor>> calleeBoundDeleteSet =
           bindSet(calleeReadSet, mapParamIdx2ParamTempDesc, mapArgIdx2CallerArgHeapPath);
       // union of the current read set and the current callee's
       // read set
-      calleeUnionBoundReadSet.addAll(calleeBoundReadSet);
-      Set<NTuple<Descriptor>> calleeBoundWriteSet =
-          bindSet(calleeOverWriteSet, mapParamIdx2ParamTempDesc, mapArgIdx2CallerArgHeapPath);
-      // intersection of the current overwrite set and the current
-      // callee's
-      // overwrite set
-      merge(calleeIntersectBoundOverWriteSet, calleeBoundWriteSet);
+      calleeUnionBoundDeleteSet.addAll(calleeBoundDeleteSet);
+
+      SharedLocMappingSet calleeSharedLocMap =
+          mapFlatMethodToSharedLocMappingSet.get(calleeFlatMethod);
+
+      Set<NTuple<Descriptor>> calleeHeapPathKeySet = calleeSharedLocMap.getHeapPathKeySet();
+
+      for (Iterator iterator2 = calleeHeapPathKeySet.iterator(); iterator2.hasNext();) {
+        NTuple<Descriptor> calleeHeapPathKey = (NTuple<Descriptor>) iterator2.next();
+
+        NTuple<Descriptor> calleeBoundHeapPathKey =
+            bind(calleeHeapPathKey, mapParamIdx2ParamTempDesc, mapArgIdx2CallerArgHeapPath);
+
+        Set<Location> calleeLocSet = calleeSharedLocMap.getLocationKeySet(calleeHeapPathKey);
+
+        for (Iterator iterator3 = calleeLocSet.iterator(); iterator3.hasNext();) {
+          Location calleeLocKey = (Location) iterator3.next();
+          Set<Descriptor> calleeWriteSet =
+              calleeSharedLocMap.getWriteSet(calleeHeapPathKey, calleeLocKey);
+
+          calleeIntersectBoundSharedSet.intersectWriteSet(calleeBoundHeapPathKey, calleeLocKey,
+              calleeWriteSet);
+
+        }
+
+      }
+
     }
 
   }
 
+  private NTuple<Descriptor> bind(NTuple<Descriptor> calleeHeapPathKey,
+      Hashtable<Integer, TempDescriptor> mapParamIdx2ParamTempDesc,
+      Hashtable<Integer, NTuple<Descriptor>> mapCallerArgIdx2HeapPath) {
+
+    Set<Integer> keySet = mapCallerArgIdx2HeapPath.keySet();
+    for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
+      Integer idx = (Integer) iterator.next();
+      NTuple<Descriptor> callerArgHeapPath = mapCallerArgIdx2HeapPath.get(idx);
+      TempDescriptor calleeParam = mapParamIdx2ParamTempDesc.get(idx);
+      if (calleeHeapPathKey.startsWith(calleeParam)) {
+        NTuple<Descriptor> boundElement = combine(callerArgHeapPath, calleeHeapPathKey);
+        return boundElement;
+      }
+    }
+    return null;
+  }
+
   private void checkFlag(boolean booleanValue, FlatNode fn, NTuple<Descriptor> hp) {
     if (booleanValue) {
-      throw new Error(
-          "There is a variable, which is reachable through references "
-              + hp
-              + ", who comes back to the same read statement without being overwritten at the out-most iteration at "
-              + methodContainingSSJavaLoop.getClassDesc().getSourceFileName() + "::"
-              + fn.getNumLine());
+      // the definitely written analysis only takes care about locations that
+      // are written to inside of the SSJava loop
+      for (Iterator iterator = calleeUnionBoundMayWriteSet.iterator(); iterator.hasNext();) {
+        NTuple<Descriptor> write = (NTuple<Descriptor>) iterator.next();
+        if (hp.startsWith(write)) {
+          // it has write effect!
+          // throw new Error(
+          System.out
+              .println("###"
+                  + "There is a variable, which is reachable through references "
+                  + hp
+                  + ", who comes back to the same read statement without being overwritten at the out-most iteration at "
+                  + methodContainingSSJavaLoop.getClassDesc().getSourceFileName() + "::"
+                  + fn.getNumLine());
+          debugcount++;
+        }
+      }
     }
   }
 
-  private void merge(Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> curr,
-      Hashtable<NTuple<Descriptor>, Hashtable<FlatNode, Boolean>> in) {
+  private void initialize() {
+    // First, identify ssjava loop entrace
 
-    Set<NTuple<Descriptor>> inKeySet = in.keySet();
-    for (Iterator iterator = inKeySet.iterator(); iterator.hasNext();) {
-      NTuple<Descriptor> inKey = (NTuple<Descriptor>) iterator.next();
-      Hashtable<FlatNode, Boolean> inPair = in.get(inKey);
+    // no need to analyze method having ssjava loop
+    methodContainingSSJavaLoop = ssjava.getMethodContainingSSJavaLoop();
+
+    FlatMethod fm = state.getMethodFlat(methodContainingSSJavaLoop);
+    Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
+    flatNodesToVisit.add(fm);
 
-      Set<FlatNode> pairKeySet = inPair.keySet();
-      for (Iterator iterator2 = pairKeySet.iterator(); iterator2.hasNext();) {
-        FlatNode pairKey = (FlatNode) iterator2.next();
-        Boolean inFlag = inPair.get(pairKey);
+    LoopFinder loopFinder = new LoopFinder(fm);
 
-        Hashtable<FlatNode, Boolean> currPair = curr.get(inKey);
-        if (currPair == null) {
-          currPair = new Hashtable<FlatNode, Boolean>();
-          curr.put(inKey, currPair);
-        }
+    while (!flatNodesToVisit.isEmpty()) {
+      FlatNode fn = flatNodesToVisit.iterator().next();
+      flatNodesToVisit.remove(fn);
 
-        Boolean currFlag = currPair.get(pairKey);
-        // by default, flag is set by false
-        if (currFlag == null) {
-          currFlag = Boolean.FALSE;
+      String label = (String) state.fn2labelMap.get(fn);
+      if (label != null) {
+
+        if (label.equals(ssjava.SSJAVA)) {
+          ssjavaLoopEntrance = fn;
+          break;
         }
-        currFlag = Boolean.valueOf(inFlag.booleanValue() | currFlag.booleanValue());
-        currPair.put(pairKey, currFlag);
       }
 
+      for (int i = 0; i < fn.numNext(); i++) {
+        FlatNode nn = fn.getNext(i);
+        flatNodesToVisit.add(nn);
+      }
+    }
+
+    assert ssjavaLoopEntrance != null;
+
+    // assume that ssjava loop is top-level loop in method, not nested loop
+    Set nestedLoop = loopFinder.nestedLoops();
+    for (Iterator loopIter = nestedLoop.iterator(); loopIter.hasNext();) {
+      LoopFinder lf = (LoopFinder) loopIter.next();
+      if (lf.loopEntrances().iterator().next().equals(ssjavaLoopEntrance)) {
+        ssjavaLoop = lf;
+      }
     }
 
-  }
+    assert ssjavaLoop != null;
 
-  private void methodReadOverWriteAnalysis() {
-    // perform method READ/OVERWRITE analysis
+    loopIncElements = (Set<FlatNode>) ssjavaLoop.loopIncElements();
+
+    // perform topological sort over the set of methods accessed by the main
+    // event loop
     Set<MethodDescriptor> methodDescriptorsToAnalyze = new HashSet<MethodDescriptor>();
     methodDescriptorsToAnalyze.addAll(ssjava.getAnnotationRequireSet());
+    sortedDescriptors = topologicalSort(methodDescriptorsToAnalyze);
+  }
 
-    LinkedList<MethodDescriptor> sortedDescriptors = topologicalSort(methodDescriptorsToAnalyze);
-
-    // no need to analyze method having ssjava loop
-    methodContainingSSJavaLoop = sortedDescriptors.removeFirst();
+  private void methodReadWriteSetAnalysis() {
+    // perform method READ/OVERWRITE analysis
+    LinkedList<MethodDescriptor> descriptorListToAnalyze =
+        (LinkedList<MethodDescriptor>) sortedDescriptors.clone();
 
     // current descriptors to visit in fixed-point interprocedural analysis,
     // prioritized by
     // dependency in the call graph
-    Stack<MethodDescriptor> methodDescriptorsToVisitStack = new Stack<MethodDescriptor>();
+    methodDescriptorsToVisitStack.clear();
+
+    descriptorListToAnalyze.removeFirst();
 
     Set<MethodDescriptor> methodDescriptorToVistSet = new HashSet<MethodDescriptor>();
-    methodDescriptorToVistSet.addAll(sortedDescriptors);
+    methodDescriptorToVistSet.addAll(descriptorListToAnalyze);
 
-    while (!sortedDescriptors.isEmpty()) {
-      MethodDescriptor md = sortedDescriptors.removeFirst();
+    while (!descriptorListToAnalyze.isEmpty()) {
+      MethodDescriptor md = descriptorListToAnalyze.removeFirst();
       methodDescriptorsToVisitStack.add(md);
     }
 
@@ -923,16 +2191,28 @@ public class DefinitelyWrittenCheck {
       FlatMethod fm = state.getMethodFlat(md);
 
       Set<NTuple<Descriptor>> readSet = new HashSet<NTuple<Descriptor>>();
-      Set<NTuple<Descriptor>> overWriteSet = new HashSet<NTuple<Descriptor>>();
-
-      methodReadOverWrite_analyzeMethod(fm, readSet, overWriteSet);
-
-      Set<NTuple<Descriptor>> prevRead = mapFlatMethodToRead.get(fm);
-      Set<NTuple<Descriptor>> prevOverWrite = mapFlatMethodToOverWrite.get(fm);
-
-      if (!(readSet.equals(prevRead) && overWriteSet.equals(prevOverWrite))) {
-        mapFlatMethodToRead.put(fm, readSet);
-        mapFlatMethodToOverWrite.put(fm, overWriteSet);
+      Set<NTuple<Descriptor>> mustWriteSet = new HashSet<NTuple<Descriptor>>();
+      Set<NTuple<Descriptor>> mayWriteSet = new HashSet<NTuple<Descriptor>>();
+      SharedLocMappingSet sharedLocMapping = new SharedLocMappingSet();
+      Set<NTuple<Descriptor>> deleteSet = new HashSet<NTuple<Descriptor>>();
+
+      methodReadWriteSet_analyzeMethod(fm, readSet, mustWriteSet, mayWriteSet, sharedLocMapping,
+          deleteSet);
+
+      Set<NTuple<Descriptor>> prevRead = mapFlatMethodToReadSet.get(fm);
+      Set<NTuple<Descriptor>> prevMustWrite = mapFlatMethodToMustWriteSet.get(fm);
+      Set<NTuple<Descriptor>> prevMayWrite = mapFlatMethodToMayWriteSet.get(fm);
+      SharedLocMappingSet prevSharedLocMapping = mapFlatMethodToSharedLocMappingSet.get(fm);
+      Set<NTuple<Descriptor>> prevDeleteSet = mapFlatMethodToDeleteSet.get(fm);
+
+      if (!(readSet.equals(prevRead) && mustWriteSet.equals(prevMustWrite)
+          && mayWriteSet.equals(prevMayWrite) && sharedLocMapping.equals(prevSharedLocMapping) && deleteSet
+            .equals(prevDeleteSet))) {
+        mapFlatMethodToReadSet.put(fm, readSet);
+        mapFlatMethodToMustWriteSet.put(fm, mustWriteSet);
+        mapFlatMethodToMayWriteSet.put(fm, mayWriteSet);
+        mapFlatMethodToSharedLocMappingSet.put(fm, sharedLocMapping);
+        mapFlatMethodToDeleteSet.put(fm, deleteSet);
 
         // results for callee changed, so enqueue dependents caller for
         // further
@@ -951,40 +2231,92 @@ public class DefinitelyWrittenCheck {
 
     }
 
+    methodReadWriteSetAnalysisToEventLoopBody();
+
+  }
+
+  private void methodReadWriteSet_analyzeMethod(FlatMethod fm, Set<NTuple<Descriptor>> readSet,
+      Set<NTuple<Descriptor>> mustWriteSet, Set<NTuple<Descriptor>> mayWriteSet,
+      SharedLocMappingSet sharedLocMapping, Set<NTuple<Descriptor>> deleteSet) {
+    if (state.SSJAVADEBUG) {
+      System.out.println("SSJAVA: Definitely written Analyzing: " + fm);
+    }
+
+    methodReadWriteSet_analyzeBody(fm, readSet, mustWriteSet, mayWriteSet, sharedLocMapping,
+        deleteSet, false);
+
   }
 
-  private void methodReadOverWrite_analyzeMethod(FlatMethod fm, Set<NTuple<Descriptor>> readSet,
-      Set<NTuple<Descriptor>> overWriteSet) {
+  private void methodReadWriteSetAnalysisToEventLoopBody() {
+
+    // perform method read/write analysis for Event Loop Body
+
+    FlatMethod flatMethodContainingSSJavaLoop = state.getMethodFlat(methodContainingSSJavaLoop);
+
     if (state.SSJAVADEBUG) {
-      System.out.println("Definitely written Analyzing: " + fm);
+      System.out.println("SSJAVA: Definitely written Event Loop Analyzing: "
+          + flatMethodContainingSSJavaLoop);
     }
 
+    Set<NTuple<Descriptor>> readSet = new HashSet<NTuple<Descriptor>>();
+    Set<NTuple<Descriptor>> mustWriteSet = new HashSet<NTuple<Descriptor>>();
+    Set<NTuple<Descriptor>> mayWriteSet = new HashSet<NTuple<Descriptor>>();
+    SharedLocMappingSet sharedLocMapping = new SharedLocMappingSet();
+    Set<NTuple<Descriptor>> deleteSet = new HashSet<NTuple<Descriptor>>();
+
+    mapFlatMethodToReadSet.put(flatMethodContainingSSJavaLoop, readSet);
+    mapFlatMethodToMustWriteSet.put(flatMethodContainingSSJavaLoop, mustWriteSet);
+    mapFlatMethodToMayWriteSet.put(flatMethodContainingSSJavaLoop, mayWriteSet);
+    mapFlatMethodToSharedLocMappingSet.put(flatMethodContainingSSJavaLoop, sharedLocMapping);
+    mapFlatMethodToDeleteSet.put(flatMethodContainingSSJavaLoop, deleteSet);
+
+    methodReadWriteSet_analyzeBody(ssjavaLoopEntrance, readSet, mustWriteSet, mayWriteSet,
+        sharedLocMapping, deleteSet, true);
+
+  }
+
+  private void methodReadWriteSet_analyzeBody(FlatNode startNode, Set<NTuple<Descriptor>> readSet,
+      Set<NTuple<Descriptor>> mustWriteSet, Set<NTuple<Descriptor>> mayWriteSet,
+      SharedLocMappingSet sharedLocMapping, Set<NTuple<Descriptor>> deleteSet,
+      boolean isEventLoopBody) {
+
     // intraprocedural analysis
     Set<FlatNode> flatNodesToVisit = new HashSet<FlatNode>();
-    flatNodesToVisit.add(fm);
+    flatNodesToVisit.add(startNode);
 
     while (!flatNodesToVisit.isEmpty()) {
       FlatNode fn = flatNodesToVisit.iterator().next();
       flatNodesToVisit.remove(fn);
 
-      Set<NTuple<Descriptor>> curr = new HashSet<NTuple<Descriptor>>();
+      SharedLocMappingSet currSharedLocMapping = new SharedLocMappingSet();
+      Set<NTuple<Descriptor>> currMustWriteSet = new HashSet<NTuple<Descriptor>>();
 
       for (int i = 0; i < fn.numPrev(); i++) {
         FlatNode prevFn = fn.getPrev(i);
-        Set<NTuple<Descriptor>> in = mapFlatNodeToWrittenSet.get(prevFn);
+        Set<NTuple<Descriptor>> in = mapFlatNodeToMustWriteSet.get(prevFn);
+        SharedLocMappingSet inSharedLoc = mapFlatNodeToSharedLocMapping.get(prevFn);
         if (in != null) {
-          merge(curr, in);
+          merge(currMustWriteSet, in);
+          merge(currSharedLocMapping, inSharedLoc);
         }
       }
 
-      methodReadOverWrite_nodeActions(fn, curr, readSet, overWriteSet);
+      methodReadWriteSet_nodeActions(fn, currMustWriteSet, readSet, mustWriteSet, mayWriteSet,
+          currSharedLocMapping, sharedLocMapping, deleteSet, isEventLoopBody);
+
+      SharedLocMappingSet prevSharedLocSet = mapFlatNodeToSharedLocMapping.get(fn);
+      Set<NTuple<Descriptor>> mustSetPrev = mapFlatNodeToMustWriteSet.get(fn);
 
-      Set<NTuple<Descriptor>> writtenSetPrev = mapFlatNodeToWrittenSet.get(fn);
-      if (!curr.equals(writtenSetPrev)) {
-        mapFlatNodeToWrittenSet.put(fn, curr);
+      if ((!currMustWriteSet.equals(mustSetPrev))
+          || (!currSharedLocMapping.equals(prevSharedLocSet))) {
+        mapFlatNodeToMustWriteSet.put(fn, currMustWriteSet);
+        mapFlatNodeToSharedLocMapping.put(fn, currSharedLocMapping);
         for (int i = 0; i < fn.numNext(); i++) {
           FlatNode nn = fn.getNext(i);
-          flatNodesToVisit.add(nn);
+          if ((!isEventLoopBody) || loopIncElements.contains(nn)) {
+            flatNodesToVisit.add(nn);
+          }
+
         }
       }
 
@@ -992,8 +2324,15 @@ public class DefinitelyWrittenCheck {
 
   }
 
-  private void methodReadOverWrite_nodeActions(FlatNode fn, Set<NTuple<Descriptor>> writtenSet,
-      Set<NTuple<Descriptor>> readSet, Set<NTuple<Descriptor>> overWriteSet) {
+  private void methodReadWriteSet_nodeActions(FlatNode fn,
+      Set<NTuple<Descriptor>> currMustWriteSet, Set<NTuple<Descriptor>> readSet,
+      Set<NTuple<Descriptor>> mustWriteSet, Set<NTuple<Descriptor>> mayWriteSet,
+      SharedLocMappingSet currSharedLocMapping, SharedLocMappingSet sharedLocMapping,
+      Set<NTuple<Descriptor>> deleteSet, boolean isEventLoopBody) {
+
+    SharedLocMappingSet killSetSharedLoc = new SharedLocMappingSet();
+    SharedLocMappingSet genSetSharedLoc = new SharedLocMappingSet();
+
     TempDescriptor lhs;
     TempDescriptor rhs;
     FieldDescriptor fld;
@@ -1023,21 +2362,80 @@ public class DefinitelyWrittenCheck {
         NTuple<Descriptor> rhsHeapPath = mapHeapPath.get(rhs);
         if (rhsHeapPath != null) {
           mapHeapPath.put(lhs, mapHeapPath.get(rhs));
+        } else {
+          NTuple<Descriptor> heapPath = new NTuple<Descriptor>();
+          heapPath.add(rhs);
+          mapHeapPath.put(lhs, heapPath);
+        }
+
+        // shared loc extension
+        if (isEventLoopBody) {
+          if (!lhs.getSymbol().startsWith("neverused") && rhs.getType().isImmutable()) {
+
+            if (rhs.getType().getExtension() instanceof Location
+                && lhs.getType().getExtension() instanceof CompositeLocation) {
+              // rhs is field!
+              Location rhsLoc = (Location) rhs.getType().getExtension();
+
+              CompositeLocation lhsCompLoc = (CompositeLocation) lhs.getType().getExtension();
+              Location dstLoc = lhsCompLoc.get(lhsCompLoc.getSize() - 1);
+
+              NTuple<Descriptor> heapPath = new NTuple<Descriptor>();
+              for (int i = 0; i < rhsHeapPath.size() - 1; i++) {
+                heapPath.add(rhsHeapPath.get(i));
+              }
+
+              NTuple<Descriptor> writeHeapPath = new NTuple<Descriptor>();
+              writeHeapPath.addAll(heapPath);
+              writeHeapPath.add(lhs);
+
+              System.out.println("VAR WRITE:" + fn);
+              System.out.println("LHS TYPE EXTENSION=" + lhs.getType().getExtension());
+              System.out.println("RHS TYPE EXTENSION=" + rhs.getType().getExtension()
+                  + " HEAPPATH=" + rhsHeapPath);
+
+              // computing gen/kill set
+              computeKILLSetForWrite(currSharedLocMapping, heapPath, dstLoc, killSetSharedLoc);
+              if (!dstLoc.equals(rhsLoc)) {
+                computeGENSetForHigherWrite(currSharedLocMapping, heapPath, dstLoc, lhs,
+                    genSetSharedLoc);
+                deleteSet.remove(writeHeapPath);
+              } else {
+                computeGENSetForSharedWrite(currSharedLocMapping, heapPath, dstLoc, lhs,
+                    genSetSharedLoc);
+                deleteSet.add(writeHeapPath);
+              }
+
+            }
+          }
         }
 
       }
     }
       break;
 
-    case FKind.FlatFieldNode:
-    case FKind.FlatElementNode: {
+    case FKind.FlatElementNode:
+    case FKind.FlatFieldNode: {
+
+      // x=y.f;
 
-      // y=x.f;
+      if (fn.kind() == FKind.FlatFieldNode) {
+        FlatFieldNode ffn = (FlatFieldNode) fn;
+        lhs = ffn.getDst();
+        rhs = ffn.getSrc();
+        fld = ffn.getField();
+      } else {
+        FlatElementNode fen = (FlatElementNode) fn;
+        lhs = fen.getDst();
+        rhs = fen.getSrc();
+        TypeDescriptor td = rhs.getType().dereference();
+        fld = getArrayField(td);
+      }
 
-      FlatFieldNode ffn = (FlatFieldNode) fn;
-      lhs = ffn.getDst();
-      rhs = ffn.getSrc();
-      fld = ffn.getField();
+      if (fld.isFinal()) {
+        // if field is final no need to check
+        break;
+      }
 
       // set up heap path
       NTuple<Descriptor> srcHeapPath = mapHeapPath.get(rhs);
@@ -1052,13 +2450,12 @@ public class DefinitelyWrittenCheck {
         // read (x.f)
         if (fld.getType().isImmutable()) {
           // if WT doesnot have hp(x.f), add hp(x.f) to READ
-          if (!writtenSet.contains(readingHeapPath)) {
+          if (!currMustWriteSet.contains(readingHeapPath)) {
             readSet.add(readingHeapPath);
           }
         }
 
-        // need to kill hp(x.f) from WT
-        writtenSet.remove(readingHeapPath);
+        // no need to kill hp(x.f) from WT
       }
 
     }
@@ -1068,23 +2465,63 @@ public class DefinitelyWrittenCheck {
     case FKind.FlatSetElementNode: {
 
       // x.f=y;
-      FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
-      lhs = fsfn.getDst();
-      fld = fsfn.getField();
-      rhs = fsfn.getSrc();
+
+      if (fn.kind() == FKind.FlatSetFieldNode) {
+        SharedLocMappingSet killSet = new SharedLocMappingSet();
+        SharedLocMappingSet genSet = new SharedLocMappingSet();
+        FlatSetFieldNode fsfn = (FlatSetFieldNode) fn;
+        lhs = fsfn.getDst();
+        fld = fsfn.getField();
+        rhs = fsfn.getSrc();
+      } else {
+        FlatSetElementNode fsen = (FlatSetElementNode) fn;
+        lhs = fsen.getDst();
+        rhs = fsen.getSrc();
+        TypeDescriptor td = lhs.getType().dereference();
+        fld = getArrayField(td);
+      }
 
       // set up heap path
       NTuple<Descriptor> lhsHeapPath = mapHeapPath.get(lhs);
+
       if (lhsHeapPath != null) {
         // if lhs heap path is null, it means that it is not reachable from
         // callee's parameters. so just ignore it
-        NTuple<Descriptor> newHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
-        newHeapPath.add(fld);
-        mapHeapPath.put(fld, newHeapPath);
+        NTuple<Descriptor> fldHeapPath = new NTuple<Descriptor>(lhsHeapPath.getList());
+        fldHeapPath.add(fld);
+        mapHeapPath.put(fld, fldHeapPath);
 
         // write(x.f)
         // need to add hp(y) to WT
-        writtenSet.add(newHeapPath);
+        currMustWriteSet.add(fldHeapPath);
+        mayWriteSet.add(fldHeapPath);
+
+        // shared loc extension
+        Location srcLoc = getLocation(rhs);
+        Location fieldLoc = (Location) fld.getType().getExtension();
+        if (ssjava.isSharedLocation(fieldLoc)) {
+          // only care the case that loc(f) is shared location
+          // write(field)
+
+          computeKILLSetForWrite(currSharedLocMapping, lhsHeapPath, fieldLoc, killSetSharedLoc);
+          if (!fieldLoc.equals(srcLoc)) {
+            computeGENSetForHigherWrite(currSharedLocMapping, lhsHeapPath, fieldLoc, fld,
+                genSetSharedLoc);
+            deleteSet.remove(fldHeapPath);
+          } else {
+            computeGENSetForSharedWrite(currSharedLocMapping, lhsHeapPath, fieldLoc, fld,
+                genSetSharedLoc);
+            deleteSet.add(fldHeapPath);
+          }
+        }
+
+        System.out.println("################");
+        System.out.println("FIELD WRITE:" + fn);
+        System.out.println("fieldLoc=" + fieldLoc + " srcLoc=" + srcLoc);
+        System.out.println("KILLSET=" + killSetSharedLoc);
+        System.out.println("GENSet=" + genSetSharedLoc);
+        System.out.println("DELETESET=" + deleteSet);
+
       }
 
     }
@@ -1094,77 +2531,207 @@ public class DefinitelyWrittenCheck {
 
       FlatCall fc = (FlatCall) fn;
 
-      bindHeapPathCallerArgWithCaleeParam(fc);
+      bindHeapPathCallerArgWithCalleeParam(fc);
+
+      mapFlatNodeToBoundReadSet.put(fn, calleeUnionBoundReadSet);
+      mapFlatNodeToBoundMustWriteSet.put(fn, calleeIntersectBoundMustWriteSet);
+      mapFlatNodeToBoundMayWriteSet.put(fn, calleeUnionBoundMayWriteSet);
 
       // add heap path, which is an element of READ_bound set and is not
       // an
       // element of WT set, to the caller's READ set
       for (Iterator iterator = calleeUnionBoundReadSet.iterator(); iterator.hasNext();) {
         NTuple<Descriptor> read = (NTuple<Descriptor>) iterator.next();
-        if (!writtenSet.contains(read)) {
+        if (!currMustWriteSet.contains(read)) {
           readSet.add(read);
         }
       }
-      writtenSet.removeAll(calleeUnionBoundReadSet);
 
       // add heap path, which is an element of OVERWRITE_bound set, to the
       // caller's WT set
-      for (Iterator iterator = calleeIntersectBoundOverWriteSet.iterator(); iterator.hasNext();) {
+      for (Iterator iterator = calleeIntersectBoundMustWriteSet.iterator(); iterator.hasNext();) {
+        NTuple<Descriptor> write = (NTuple<Descriptor>) iterator.next();
+        currMustWriteSet.add(write);
+      }
+
+      // add heap path, which is an element of WRITE_BOUND set, to the
+      // caller's writeSet
+      for (Iterator iterator = calleeUnionBoundMayWriteSet.iterator(); iterator.hasNext();) {
         NTuple<Descriptor> write = (NTuple<Descriptor>) iterator.next();
-        writtenSet.add(write);
+        mayWriteSet.add(write);
       }
 
+      // shared loc extension
+      bindHeapPathCallerArgWithCaleeParamForSharedLoc(fc);
+
+      generateKILLSharedSetForFlatCall(currSharedLocMapping, killSetSharedLoc);
+      generateGENSharedSetForFlatCall(currSharedLocMapping, genSetSharedLoc);
+
+      System.out.println("### Analyzing FC=" + fc);
+      System.out.println("### BOUNDSET=" + calleeIntersectBoundSharedSet);
+      System.out.println("### GEN=" + genSetSharedLoc);
+      System.out.println("### KILL=" + killSetSharedLoc);
     }
       break;
 
     case FKind.FlatExit: {
       // merge the current written set with OVERWRITE set
-      merge(overWriteSet, writtenSet);
+      merge(mustWriteSet, currMustWriteSet);
+
+      // shared loc extension
+      merge(sharedLocMapping, currSharedLocMapping);
     }
       break;
 
     }
 
+    computeNewMapping(currSharedLocMapping, killSetSharedLoc, genSetSharedLoc);
+
   }
 
-  private void mergeSharedAnaylsis(Hashtable<NTuple<Descriptor>, SharedLocState> curr,
-      Hashtable<NTuple<Descriptor>, SharedLocState> in) {
+  private void generateGENSharedSetForFlatCall(SharedLocMappingSet currSharedLocMapping,
+      SharedLocMappingSet genSetSharedLoc) {
 
-    Set<NTuple<Descriptor>> keySet = in.keySet();
-    for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
+    Set<NTuple<Descriptor>> hpKeySet = calleeIntersectBoundSharedSet.getHeapPathKeySet();
+    for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
       NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
-      SharedLocState inState = in.get(hpKey);
+      Set<Location> locKeySet = calleeIntersectBoundSharedSet.getLocationKeySet(hpKey);
+      for (Iterator iterator2 = locKeySet.iterator(); iterator2.hasNext();) {
+        Location locKey = (Location) iterator2.next();
+
+        Set<Descriptor> calleeBoundWriteSet =
+            calleeIntersectBoundSharedSet.getWriteSet(hpKey, locKey);
+        System.out.println("calleeBoundWriteSet=" + calleeBoundWriteSet + " hp=" + hpKey + " loc="
+            + locKey);
+        Set<Descriptor> removeSet = computeRemoveSet(hpKey, locKey);
+
+        Set<Descriptor> currWriteSet = currSharedLocMapping.getWriteSet(hpKey, locKey);
+
+        genSetSharedLoc.addWriteSet(hpKey, locKey, currWriteSet);
+        genSetSharedLoc.addWriteSet(hpKey, locKey, calleeBoundWriteSet);
+        genSetSharedLoc.removeWriteSet(hpKey, locKey, removeSet);
 
-      SharedLocState currState = curr.get(hpKey);
-      if (currState == null) {
-        currState = new SharedLocState();
-        curr.put(hpKey, currState);
       }
-      currState.merge(inState);
+    }
 
-      Set<Location> locSet = inState.getMap().keySet();
-      for (Iterator iterator2 = locSet.iterator(); iterator2.hasNext();) {
-        Location loc = (Location) iterator2.next();
-        Pair<Set<Descriptor>, Boolean> pair = inState.getMap().get(loc);
-        boolean inFlag = pair.getSecond().booleanValue();
-
-        Pair<NTuple<Descriptor>, Location> flagKey =
-            new Pair<NTuple<Descriptor>, Location>(hpKey, loc);
-        Boolean current = mapHeapPathLocation2Flag.get(flagKey);
-        if (current == null) {
-          current = new Boolean(true);
+  }
+
+  public NTuple<Descriptor> getPrefix(NTuple<Descriptor> in) {
+    return in.subList(0, in.size() - 1);
+  }
+
+  public NTuple<Descriptor> getSuffix(NTuple<Descriptor> in) {
+    return in.subList(in.size() - 1, in.size());
+  }
+
+  private Set<Descriptor> computeRemoveSet(NTuple<Descriptor> hpKey, Location locKey) {
+    Set<Descriptor> removeSet = new HashSet<Descriptor>();
+
+    for (Iterator iterator = calleeUnionBoundDeleteSet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> removeHeapPath = (NTuple<Descriptor>) iterator.next();
+      if (getPrefix(removeHeapPath).equals(hpKey)) {
+        removeSet.add(getSuffix(removeHeapPath).get(0));
+      }
+    }
+
+    return removeSet;
+  }
+
+  private void generateKILLSharedSetForFlatCall(SharedLocMappingSet currSharedLocMapping,
+      SharedLocMappingSet killSetSharedLoc) {
+
+    Set<NTuple<Descriptor>> hpKeySet = calleeIntersectBoundSharedSet.getHeapPathKeySet();
+    for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+      Set<Location> locKeySet = calleeIntersectBoundSharedSet.getLocationKeySet(hpKey);
+      for (Iterator iterator2 = locKeySet.iterator(); iterator2.hasNext();) {
+        Location locKey = (Location) iterator2.next();
+        Set<Descriptor> currWriteSet = currSharedLocMapping.getWriteSet(hpKey, locKey);
+        killSetSharedLoc.addWriteSet(hpKey, locKey, currWriteSet);
+      }
+    }
+  }
+
+  static public FieldDescriptor getArrayField(TypeDescriptor td) {
+    FieldDescriptor fd = mapTypeToArrayField.get(td);
+    if (fd == null) {
+      fd =
+          new FieldDescriptor(new Modifiers(Modifiers.PUBLIC), td, arrayElementFieldName, null,
+              false);
+      mapTypeToArrayField.put(td, fd);
+    }
+    return fd;
+  }
+
+  private void mergeSharedLocationAnaylsis(ClearingSummary curr, Set<ClearingSummary> inSet) {
+    if (inSet.size() == 0) {
+      return;
+    }
+    Hashtable<Pair<NTuple<Descriptor>, Location>, Boolean> mapHeapPathLoc2Flag =
+        new Hashtable<Pair<NTuple<Descriptor>, Location>, Boolean>();
+
+    for (Iterator inIterator = inSet.iterator(); inIterator.hasNext();) {
+
+      ClearingSummary inTable = (ClearingSummary) inIterator.next();
+
+      Set<NTuple<Descriptor>> keySet = inTable.keySet();
+
+      for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
+        NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+        SharedStatus inState = inTable.get(hpKey);
+        SharedStatus currState = curr.get(hpKey);
+        if (currState == null) {
+          currState = new SharedStatus();
+          curr.put(hpKey, currState);
+        }
+
+        currState.merge(inState);
+
+        Set<Location> locSet = inState.getMap().keySet();
+        for (Iterator iterator2 = locSet.iterator(); iterator2.hasNext();) {
+          Location loc = (Location) iterator2.next();
+          Pair<Set<Descriptor>, Boolean> pair = inState.getMap().get(loc);
+          boolean inFlag = pair.getSecond().booleanValue();
+
+          Pair<NTuple<Descriptor>, Location> flagKey =
+              new Pair<NTuple<Descriptor>, Location>(hpKey, loc);
+          Boolean current = mapHeapPathLoc2Flag.get(flagKey);
+          if (current == null) {
+            current = new Boolean(true);
+          }
+          boolean newInFlag = current.booleanValue() & inFlag;
+          mapHeapPathLoc2Flag.put(flagKey, Boolean.valueOf(newInFlag));
         }
-        boolean newInFlag = current.booleanValue() & inFlag;
-        mapHeapPathLocation2Flag.put(flagKey, Boolean.valueOf(newInFlag));
+
       }
 
     }
 
+    // merge flag status
+    Set<NTuple<Descriptor>> hpKeySet = curr.keySet();
+    for (Iterator iterator = hpKeySet.iterator(); iterator.hasNext();) {
+      NTuple<Descriptor> hpKey = (NTuple<Descriptor>) iterator.next();
+      SharedStatus currState = curr.get(hpKey);
+      Set<Location> locKeySet = currState.getMap().keySet();
+      for (Iterator iterator2 = locKeySet.iterator(); iterator2.hasNext();) {
+        Location locKey = (Location) iterator2.next();
+        Pair<Set<Descriptor>, Boolean> pair = currState.getMap().get(locKey);
+        boolean currentFlag = pair.getSecond().booleanValue();
+        Boolean inFlag = mapHeapPathLoc2Flag.get(new Pair(hpKey, locKey));
+        if (inFlag != null) {
+          boolean newFlag = currentFlag | inFlag.booleanValue();
+          if (currentFlag != newFlag) {
+            currState.getMap().put(locKey, new Pair(pair.getFirst(), new Boolean(newFlag)));
+          }
+        }
+      }
+    }
+
   }
 
   private void merge(Set<NTuple<Descriptor>> curr, Set<NTuple<Descriptor>> in) {
     if (curr.isEmpty()) {
-      // WrittenSet has a special initial value which covers all possible
+      // set has a special initial value which covers all possible
       // elements
       // For the first time of intersection, we can take all previous set
       curr.addAll(in);
@@ -1205,7 +2772,6 @@ public class DefinitelyWrittenCheck {
 
       NTuple<Descriptor> callerArgHeapPath = mapCallerArgIdx2HeapPath.get(idx);
       TempDescriptor calleeParam = mapParamIdx2ParamTempDesc.get(idx);
-
       for (Iterator iterator2 = calleeSet.iterator(); iterator2.hasNext();) {
         NTuple<Descriptor> element = (NTuple<Descriptor>) iterator2.next();
         if (element.startsWith(calleeParam)) {
@@ -1251,16 +2817,13 @@ public class DefinitelyWrittenCheck {
 
     discovered.add(md);
 
-    // otherwise call graph guides DFS
     Iterator itr = callGraph.getCallerSet(md).iterator();
     while (itr.hasNext()) {
       MethodDescriptor dCaller = (MethodDescriptor) itr.next();
-
       // only consider callers in the original set to analyze
       if (!toSort.contains(dCaller)) {
         continue;
       }
-
       if (!discovered.contains(dCaller)) {
         addDependent(md, // callee
             dCaller // caller
@@ -1307,4 +2870,40 @@ public class DefinitelyWrittenCheck {
     }
   }
 
+  private NTuple<Location> deriveThisLocationTuple(MethodDescriptor md) {
+    String thisLocIdentifier = ssjava.getMethodLattice(md).getThisLoc();
+    Location thisLoc = new Location(md, thisLocIdentifier);
+    NTuple<Location> locTuple = new NTuple<Location>();
+    locTuple.add(thisLoc);
+    return locTuple;
+  }
+
+  private NTuple<Location> deriveLocationTuple(MethodDescriptor md, TempDescriptor td) {
+
+    assert td.getType() != null;
+
+    if (mapDescriptorToLocationStrPath.containsKey(td)) {
+      return mapDescriptorToLocationStrPath.get(td);
+    } else {
+      if (td.getSymbol().startsWith("this")) {
+        return deriveThisLocationTuple(md);
+      } else {
+        NTuple<Location> locTuple =
+            ((SSJavaType) td.getType().getExtension()).getCompLoc().getTuple();
+        return locTuple;
+      }
+    }
+
+  }
+
+  private NTuple<Location> deriveLocationTuple(MethodDescriptor md, FieldDescriptor fld) {
+
+    assert fld.getType() != null;
+
+    Location fieldLoc = (Location) fld.getType().getExtension();
+    NTuple<Location> locTuple = new NTuple<Location>();
+    locTuple.add(fieldLoc);
+    return locTuple;
+  }
+
 }
\ No newline at end of file