X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=Robust%2Fsrc%2FAnalysis%2FSSJava%2FFlowGraph.java;h=2031460dd48cc983a8bd974aabfa0d93b6ce4314;hb=ddac34bb8ed87db61d32630e714e7f006a077c8e;hp=f9790963afc1fe18026f3348f23b8f7052249031;hpb=28876fc6038265b38688ea04cd0f5d8241604bd6;p=IRC.git

diff --git a/Robust/src/Analysis/SSJava/FlowGraph.java b/Robust/src/Analysis/SSJava/FlowGraph.java
index f9790963..2031460d 100644
--- a/Robust/src/Analysis/SSJava/FlowGraph.java
+++ b/Robust/src/Analysis/SSJava/FlowGraph.java
@@ -1,96 +1,937 @@
 package Analysis.SSJava;
 
+import java.io.BufferedWriter;
+import java.io.FileWriter;
+import java.io.IOException;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 
+import IR.ClassDescriptor;
 import IR.Descriptor;
+import IR.FieldDescriptor;
 import IR.MethodDescriptor;
+import IR.NameDescriptor;
+import IR.VarDescriptor;
+import IR.Tree.MethodInvokeNode;
 
 public class FlowGraph {
 
   MethodDescriptor md;
 
-  Set<FlowNode> nodeSet;
+  Set<FlowNode> returnNodeSet;
   FlowNode thisVarNode;
 
+  Map<FlowNode, Set<FlowEdge>> mapFlowNodeToInEdgeSet;
+  Map<FlowNode, Set<FlowEdge>> mapFlowNodeToOutEdgeSet;
+
+  Map<NTuple<Location>, FlowNode> mapLocTupleToFlowNode;
+  Map<FlowNode, NTuple<Location>> mapFlowNodeToLocTuple;
+
   // maps the composite representation of field/var descriptors to infer nodes
   Map<NTuple<Descriptor>, FlowNode> mapDescTupleToInferNode;
 
-  // maps an infer node to the set of neighbors which is pointed by the node
-  Map<NTuple<Descriptor>, Set<FlowNode>> mapNodeToNeighborSet;
+  // maps a paramter descriptor to its index
+  Map<Descriptor, Integer> mapParamDescToIdx;
+
+  // DS for the lattice generation
+  Map<Integer, FlowNode> mapIdxToFlowNode;
+
+  Map<MethodInvokeNode, FlowReturnNode> mapMethodInvokeNodeToFlowReturnNode;
+
+  Map<Descriptor, ClassDescriptor> mapIntersectionDescToEnclosingDescriptor;
+
+  public static int interseed = 0;
 
   boolean debug = true;
 
-  public FlowGraph(MethodDescriptor md) {
+  public FlowGraph(MethodDescriptor md, Map<Descriptor, Integer> mapParamDescToIdx) {
     this.md = md;
-    nodeSet = new HashSet<FlowNode>();
-    mapDescTupleToInferNode = new HashMap<NTuple<Descriptor>, FlowNode>();
-    mapNodeToNeighborSet = new HashMap<NTuple<Descriptor>, Set<FlowNode>>();
+    this.mapFlowNodeToLocTuple = new HashMap<FlowNode, NTuple<Location>>();
+    this.mapLocTupleToFlowNode = new HashMap<NTuple<Location>, FlowNode>();
+    this.mapDescTupleToInferNode = new HashMap<NTuple<Descriptor>, FlowNode>();
+    this.mapParamDescToIdx = new HashMap<Descriptor, Integer>();
+    this.mapParamDescToIdx.putAll(mapParamDescToIdx);
+    this.returnNodeSet = new HashSet<FlowNode>();
+    this.mapIdxToFlowNode = new HashMap<Integer, FlowNode>();
+    this.mapFlowNodeToOutEdgeSet = new HashMap<FlowNode, Set<FlowEdge>>();
+    this.mapFlowNodeToInEdgeSet = new HashMap<FlowNode, Set<FlowEdge>>();
+    this.mapMethodInvokeNodeToFlowReturnNode = new HashMap<MethodInvokeNode, FlowReturnNode>();
+    this.mapIntersectionDescToEnclosingDescriptor = new HashMap<Descriptor, ClassDescriptor>();
+
+    if (!md.isStatic()) {
+      // create a node for 'this' varialbe
+      // NTuple<Descriptor> thisDescTuple = new NTuple<Descriptor>();
+      // thisDescTuple.add(md.getThis());
+
+      NTuple<Descriptor> thisVarTuple = new NTuple<Descriptor>();
+      thisVarTuple.add(md.getThis());
+      FlowNode thisNode = createNewFlowNode(thisVarTuple);
+      thisNode.setSkeleton(true);
+      thisVarNode = thisNode;
+    }
+
+    setupMapIdxToDesc();
+
+  }
+
+  public void addMapInterLocNodeToEnclosingDescriptor(Descriptor interDesc, ClassDescriptor desc) {
+    System.out.println("##### INTERLOC=" + interDesc + "    enclosing desc=" + desc);
+    mapIntersectionDescToEnclosingDescriptor.put(interDesc, desc);
+  }
+
+  public ClassDescriptor getEnclosingDescriptor(Descriptor interDesc) {
+    return mapIntersectionDescToEnclosingDescriptor.get(interDesc);
+  }
+
+  public Map<NTuple<Descriptor>, FlowNode> getMapDescTupleToInferNode() {
+    return mapDescTupleToInferNode;
+  }
+
+  public void setMapDescTupleToInferNode(Map<NTuple<Descriptor>, FlowNode> in) {
+    this.mapDescTupleToInferNode.putAll(in);
+  }
+
+  public Map<NTuple<Location>, FlowNode> getMapLocTupleToFlowNode() {
+    return mapLocTupleToFlowNode;
+  }
+
+  public void setMapLocTupleToFlowNode(Map<NTuple<Location>, FlowNode> in) {
+    this.mapLocTupleToFlowNode.putAll(in);
+  }
+
+  public void setReturnNodeSet(Set<FlowNode> in) {
+    this.returnNodeSet.addAll(in);
+  }
+
+  public void setThisVarNode(FlowNode thisVarNode) {
+    this.thisVarNode = thisVarNode;
+  }
+
+  public Map<Descriptor, Integer> getMapParamDescToIdx() {
+    return mapParamDescToIdx;
+  }
+
+  public FlowNode createIntermediateNode() {
+    NTuple<Descriptor> tuple = new NTuple<Descriptor>();
+    Descriptor interDesc = new InterDescriptor(LocationInference.INTERLOC + interseed);
+    tuple.add(interDesc);
+    interseed++;
+
+    FlowNode newNode = new FlowNode(tuple);
+    newNode.setIntermediate(true);
+
+    mapDescTupleToInferNode.put(tuple, newNode);
+    // nodeSet.add(newNode);
 
-    // create a node for 'this' varialbe
-    FlowNode thisNode = new FlowNode(null, md.getThis());
-    NTuple<Descriptor> thisVarTuple = new NTuple<Descriptor>();
-    thisVarTuple.add(md.getThis());
-    mapDescTupleToInferNode.put(thisVarTuple, thisNode);
-    thisVarNode = thisNode;
+    System.out.println("create new intermediate node= " + newNode);
 
+    return newNode;
   }
 
-  public void addNeighbor(FlowNode node, FlowNode neighbor) {
-    Set<FlowNode> set = mapNodeToNeighborSet.get(node);
-    if (set == null) {
-      set = new HashSet<FlowNode>();
+  public FlowReturnNode getFlowReturnNode(MethodInvokeNode min) {
+    return mapMethodInvokeNodeToFlowReturnNode.get(min);
+  }
+
+  public FlowReturnNode createReturnNode(MethodInvokeNode min) {
+    NTuple<Descriptor> tuple = new NTuple<Descriptor>();
+    NameDescriptor n = new NameDescriptor("RETURNLOC" + (LocationInference.locSeed++));
+    tuple.add(n);
+
+    FlowReturnNode newNode = new FlowReturnNode(tuple, min);
+    mapDescTupleToInferNode.put(tuple, newNode);
+    mapMethodInvokeNodeToFlowReturnNode.put(min, newNode);
+    // nodeSet.add(newNode);
+
+    System.out.println("create new set node= " + newNode);
+
+    return newNode;
+  }
+
+  private void setupMapIdxToDesc() {
+
+    Set<Descriptor> descSet = mapParamDescToIdx.keySet();
+    for (Iterator iterator = descSet.iterator(); iterator.hasNext();) {
+      Descriptor paramDesc = (Descriptor) iterator.next();
+      int idx = mapParamDescToIdx.get(paramDesc);
+      NTuple<Descriptor> descTuple = new NTuple<Descriptor>();
+      descTuple.add(paramDesc);
+      FlowNode paramNode = getFlowNode(descTuple);
+      mapIdxToFlowNode.put(idx, paramNode);
+      paramNode.setSkeleton(true);
     }
-    set.add(neighbor);
 
-    System.out.println("add a new neighbor " + neighbor + " to " + node);
   }
 
-  public void addValueFlowEdge(NTuple<Descriptor> fromDescTuple, NTuple<Descriptor> toDescTuple) {
+  public int getNumParameters() {
+    return mapIdxToFlowNode.keySet().size();
+  }
+
+  public FlowNode getParamFlowNode(int idx) {
+    return mapIdxToFlowNode.get(idx);
+  }
+
+  public Set<FlowEdge> getEdgeSet() {
+    Set<FlowEdge> edgeSet = new HashSet<FlowEdge>();
+
+    Set<FlowNode> nodeSet = getNodeSet();
+    for (Iterator iterator = nodeSet.iterator(); iterator.hasNext();) {
+      FlowNode flowNode = (FlowNode) iterator.next();
+      edgeSet.addAll(getOutEdgeSet(flowNode));
+    }
+    System.out.println("EDGESET=" + edgeSet);
+    return edgeSet;
+  }
+
+  public Set<FlowNode> getParamFlowNodeSet() {
+    Set<FlowNode> setParamFlowNode = new HashSet<FlowNode>();
+    setParamFlowNode.addAll(mapIdxToFlowNode.values());
+    return setParamFlowNode;
+  }
+
+  public Set<FlowNode> getNodeSet() {
+    Set<FlowNode> set = new HashSet<FlowNode>();
+    set.addAll(mapDescTupleToInferNode.values());
+    System.out.println("NODESET=" + set);
+    return set;
+  }
+
+  public MethodDescriptor getMethodDescriptor() {
+    return md;
+  }
+
+  public boolean isParamDesc(Descriptor desc) {
+
+    if (mapParamDescToIdx.containsKey(desc)) {
+      int idx = mapParamDescToIdx.get(desc);
+      if (!md.isStatic() && idx == 0) {
+        return false;
+      }
+      return true;
+    }
+
+    return false;
+  }
+
+  public boolean hasEdge(NTuple<Descriptor> fromDescTuple, NTuple<Descriptor> toDescTuple) {
 
     FlowNode fromNode = mapDescTupleToInferNode.get(fromDescTuple);
     FlowNode toNode = mapDescTupleToInferNode.get(toDescTuple);
 
-    System.out.println("create an edge from " + fromNode + " to " + toNode);
+    Set<FlowEdge> fromNodeOutEdgeSet = getOutEdgeSet(fromNode);
+    for (Iterator iterator = fromNodeOutEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge flowEdge = (FlowEdge) iterator.next();
+      if (flowEdge.getDst().equals(toNode)) {
+        return true;
+      } else {
+        if (hasEdge(flowEdge.getDst().getDescTuple(), toDescTuple)) {
+          return true;
+        }
+      }
+    }
+
+    return false;
+  }
+
+  public Set<FlowEdge> getOutEdgeSetStartingFrom(FlowNode startNode) {
+
+    Descriptor prefixDesc = startNode.getCurrentDescTuple().get(0);
+
+    // returns the set of edges that share the same prefix of startNode
+    Set<FlowEdge> edgeSet = new HashSet<FlowEdge>();
+
+    for (Iterator<Set<FlowEdge>> iter = mapFlowNodeToOutEdgeSet.values().iterator(); iter.hasNext();) {
+      Set<FlowEdge> nodeEdgeSet = iter.next();
+      for (Iterator<FlowEdge> iter2 = nodeEdgeSet.iterator(); iter2.hasNext();) {
+        FlowEdge edge = iter2.next();
+        if (edge.getInitTuple().get(0).equals(prefixDesc)) {
+          edgeSet.add(edge);
+        }
+      }
+    }
+
+    return edgeSet;
+  }
+
+  public Set<FlowEdge> getOutEdgeSet(FlowNode node) {
+    if (!mapFlowNodeToOutEdgeSet.containsKey(node)) {
+      mapFlowNodeToOutEdgeSet.put(node, new HashSet<FlowEdge>());
+    }
+    return mapFlowNodeToOutEdgeSet.get(node);
+  }
+
+  public Set<FlowEdge> getInEdgeSet(FlowNode node) {
+    if (!mapFlowNodeToInEdgeSet.containsKey(node)) {
+      mapFlowNodeToInEdgeSet.put(node, new HashSet<FlowEdge>());
+    }
+    return mapFlowNodeToInEdgeSet.get(node);
+  }
+
+  public void addValueFlowEdge(NTuple<Descriptor> fromDescTuple, NTuple<Descriptor> toDescTuple) {
+
+    FlowNode fromNode = getFlowNode(fromDescTuple);
+    FlowNode toNode = getFlowNode(toDescTuple);
+
+    if (toNode.getDescTuple().get(0).equals(LocationInference.LITERALDESC)) {
+      return;
+    }
+
+    // System.out.println("create an edge from " + fromNode + " to " + toNode);
 
     int fromTupleSize = fromDescTuple.size();
-    NTuple<Descriptor> curTuple = new NTuple<Descriptor>();
+    NTuple<Descriptor> curFromTuple = new NTuple<Descriptor>();
     for (int i = 0; i < fromTupleSize; i++) {
       Descriptor desc = fromDescTuple.get(i);
-      curTuple.add(desc);
-      addNeighbor(getInferNode(curTuple), toNode);
+      curFromTuple.add(desc);
+      int toTupleSize = toDescTuple.size();
+      NTuple<Descriptor> curToTuple = new NTuple<Descriptor>();
+      for (int k = 0; k < toTupleSize; k++) {
+        Descriptor toDesc = toDescTuple.get(k);
+        curToTuple.add(toDesc);
+        addFlowEdge(getFlowNode(curFromTuple), getFlowNode(curToTuple), fromDescTuple, toDescTuple);
+      }
     }
 
-    int toTupleSize = toDescTuple.size();
-    curTuple = new NTuple<Descriptor>();
-    for (int i = 0; i < toTupleSize; i++) {
-      Descriptor desc = toDescTuple.get(i);
-      curTuple.add(desc);
-      addNeighbor(fromNode, getInferNode(curTuple));
+    // int fromTupleSize = fromDescTuple.size();
+    // NTuple<Descriptor> curTuple = new NTuple<Descriptor>();
+    // for (int i = 0; i < fromTupleSize; i++) {
+    // Descriptor desc = fromDescTuple.get(i);
+    // curTuple.add(desc);
+    // addFlowEdge(getFlowNode(curTuple), toNode, fromDescTuple, toDescTuple);
+    // }
+    //
+    // int toTupleSize = toDescTuple.size();
+    // curTuple = new NTuple<Descriptor>();
+    // for (int i = 0; i < toTupleSize; i++) {
+    // Descriptor desc = toDescTuple.get(i);
+    // curTuple.add(desc);
+    // addFlowEdge(fromNode, getFlowNode(curTuple), fromDescTuple, toDescTuple);
+    // }
+
+  }
+
+  private void addFlowEdge(FlowNode fromNode, FlowNode toNode, NTuple<Descriptor> initTuple,
+      NTuple<Descriptor> endTuple) {
+
+    FlowEdge edge = new FlowEdge(fromNode, toNode, initTuple, endTuple);
+    addOutEdge(fromNode, edge);
+    addInEdge(toNode, edge);
+
+    // System.out.println("add a new edge=" + edge);
+  }
+
+  private void addInEdge(FlowNode toNode, FlowEdge edge) {
+    getInEdgeSet(toNode).add(edge);
+  }
+
+  private void addOutEdge(FlowNode fromNode, FlowEdge edge) {
+    if (!mapFlowNodeToOutEdgeSet.containsKey(fromNode)) {
+      mapFlowNodeToOutEdgeSet.put(fromNode, new HashSet<FlowEdge>());
     }
+    mapFlowNodeToOutEdgeSet.get(fromNode).add(edge);
+  }
 
+  public boolean contains(NTuple<Descriptor> descTuple) {
+    return mapDescTupleToInferNode.containsKey(descTuple);
   }
 
-  public FlowNode getInferNode(NTuple<Descriptor> descTuple) {
-    if (mapDescTupleToInferNode.containsKey(descTuple)) {
-      return mapDescTupleToInferNode.get(descTuple);
+  public FlowNode getFlowNode(NTuple<Descriptor> descTuple) {
+    if (!mapDescTupleToInferNode.containsKey(descTuple)) {
+      FlowNode node = createNewFlowNode(descTuple);
+      mapDescTupleToInferNode.put(descTuple, node);
     }
-    return null;
+    return mapDescTupleToInferNode.get(descTuple);
   }
 
   public FlowNode getThisVarNode() {
     return thisVarNode;
   }
 
-  public void createNewFlowNode(NTuple<Descriptor> base) {
+  public FlowNode createNewFlowNode(NTuple<Descriptor> tuple) {
+
+    // System.out.println("createNewFlowNode=" + tuple);
+    if (!mapDescTupleToInferNode.containsKey(tuple)) {
+      FlowNode node = new FlowNode(tuple);
+      mapDescTupleToInferNode.put(tuple, node);
+      // nodeSet.add(node);
+
+      mapLocTupleToFlowNode.put(getLocationTuple(node), node);
 
-    FlowNode node = new FlowNode(base);
-    mapDescTupleToInferNode.put(base, node);
+      if (tuple.size() > 1) {
+        NTuple<Descriptor> baseTuple = tuple.subList(0, tuple.size() - 1);
+        getFlowNode(baseTuple).addFieldNode(node);
+      }
 
-    System.out.println("Creating new node=" + node);
+      // System.out.println("Creating new node=" + node);
+      return node;
+    } else {
+      return mapDescTupleToInferNode.get(tuple);
+    }
 
   }
 
-}
+  public void addReturnFlowNode(NTuple<Descriptor> tuple) {
+
+    if (!mapDescTupleToInferNode.containsKey(tuple)) {
+      createNewFlowNode(tuple);
+    }
+
+    FlowNode node = mapDescTupleToInferNode.get(tuple);
+    returnNodeSet.add(node);
+  }
+
+  public Set<FlowNode> getReturnNodeSet() {
+    return returnNodeSet;
+  }
+
+  public Set<FlowNode> getLocalReachFlowNodeSetFrom(FlowNode fn) {
+    Set<FlowNode> set = new HashSet<FlowNode>();
+    recurLocalReachFlowNodeSet(fn, set);
+    return set;
+  }
+
+  private void recurLocalReachFlowNodeSet(FlowNode fn, Set<FlowNode> visited) {
+
+    Set<FlowEdge> outEdgeSet = getOutEdgeSet(fn);
+    for (Iterator iterator = outEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge edge = (FlowEdge) iterator.next();
+      FlowNode originalDstNode = edge.getDst();
+
+      Set<FlowNode> dstNodeSet = new HashSet<FlowNode>();
+      if (originalDstNode instanceof FlowReturnNode) {
+        FlowReturnNode rnode = (FlowReturnNode) originalDstNode;
+        Set<NTuple<Descriptor>> rtupleSetFromRNode = rnode.getReturnTupleSet();
+        Set<NTuple<Descriptor>> rtupleSet = getReturnTupleSet(rtupleSetFromRNode);
+        for (Iterator iterator2 = rtupleSet.iterator(); iterator2.hasNext();) {
+          NTuple<Descriptor> rtuple = (NTuple<Descriptor>) iterator2.next();
+          dstNodeSet.add(getFlowNode(rtuple));
+        }
+      } else {
+        dstNodeSet.add(originalDstNode);
+      }
+
+      for (Iterator iterator2 = dstNodeSet.iterator(); iterator2.hasNext();) {
+        FlowNode dstNode = (FlowNode) iterator2.next();
+        if (!visited.contains(dstNode)) {
+          visited.add(dstNode);
+          recurLocalReachFlowNodeSet(dstNode, visited);
+        }
+      }
+
+    }
+
+  }
+
+  private void getReachFlowNodeSetFrom(FlowNode fn, Set<FlowNode> visited) {
+
+    Set<FlowEdge> outEdgeSet = getOutEdgeSet(fn);
+    for (Iterator iterator = outEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge edge = (FlowEdge) iterator.next();
+
+      if (fn.equals(getFlowNode(edge.getInitTuple()))) {
+        FlowNode dstNode = getFlowNode(edge.getEndTuple());
+        if (!visited.contains(dstNode)) {
+          visited.add(dstNode);
+          getReachFlowNodeSetFrom(dstNode, visited);
+        }
+      }
+    }
+
+  }
+
+  public Set<FlowNode> getReachFlowNodeSetFrom(FlowNode fn) {
+    Set<FlowNode> set = new HashSet<FlowNode>();
+    getReachFlowNodeSetFrom(fn, set);
+    return set;
+  }
+
+  public Set<FlowNode> getReachableSetFrom(NTuple<Descriptor> prefix) {
+    Set<FlowNode> reachableSet = new HashSet<FlowNode>();
+
+    Set<FlowNode> nodeSet = getNodeSet();
+    for (Iterator iterator = nodeSet.iterator(); iterator.hasNext();) {
+      FlowNode originalSrcNode = (FlowNode) iterator.next();
+
+      Set<FlowNode> srcNodeSet = new HashSet<FlowNode>();
+      if (originalSrcNode instanceof FlowReturnNode) {
+        FlowReturnNode rnode = (FlowReturnNode) originalSrcNode;
+        Set<NTuple<Descriptor>> rtupleSetFromRNode = rnode.getReturnTupleSet();
+        Set<NTuple<Descriptor>> rtupleSet = getReturnTupleSet(rtupleSetFromRNode);
+        // System.out.println("#rnode=" + rnode + "  rtupleSet=" + rtupleSet);
+        for (Iterator iterator2 = rtupleSet.iterator(); iterator2.hasNext();) {
+          NTuple<Descriptor> rtuple = (NTuple<Descriptor>) iterator2.next();
+          if (rtuple.startsWith(prefix)) {
+            // System.out.println("rtuple=" + rtuple + "   give it to recur=" + originalSrcNode);
+            recurReachableSetFrom(originalSrcNode, reachableSet);
+          }
+        }
+      } else {
+        if (originalSrcNode.getCurrentDescTuple().startsWith(prefix)) {
+          recurReachableSetFrom(originalSrcNode, reachableSet);
+        }
+      }
+
+    }
+
+    return reachableSet;
+  }
+
+  public Set<NTuple<Descriptor>> getReturnTupleSet(Set<NTuple<Descriptor>> in) {
+
+    Set<NTuple<Descriptor>> normalTupleSet = new HashSet<NTuple<Descriptor>>();
+    for (Iterator iterator2 = in.iterator(); iterator2.hasNext();) {
+      NTuple<Descriptor> tuple = (NTuple<Descriptor>) iterator2.next();
+      FlowNode tupleNode = getFlowNode(tuple);
+      if (tupleNode instanceof FlowReturnNode) {
+        normalTupleSet.addAll(getReturnTupleSet(((FlowReturnNode) tupleNode).getReturnTupleSet()));
+      } else {
+        normalTupleSet.add(tuple);
+      }
+    }
+    return normalTupleSet;
+  }
+
+  // private void getReachFlowNodeSetFrom(FlowNode fn, Set<FlowNode> visited) {
+  //
+  // for (Iterator iterator = fn.getOutEdgeSet().iterator();
+  // iterator.hasNext();) {
+  // FlowEdge edge = (FlowEdge) iterator.next();
+  //
+  // if (fn.equals(getFlowNode(edge.getInitTuple()))) {
+  //
+  // FlowNode dstNode = getFlowNode(edge.getEndTuple());
+  //
+  // if (!visited.contains(dstNode)) {
+  // visited.add(dstNode);
+  // getReachFlowNodeSetFrom(dstNode, visited);
+  // }
+  // }
+  // }
+  //
+  // }
+
+  private void recurReachableSetFrom(FlowNode curNode, Set<FlowNode> reachableSet) {
+
+    Set<FlowEdge> edgeSet = getOutEdgeSet(curNode);
+    for (Iterator iterator = edgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge edge = (FlowEdge) iterator.next();
+      FlowNode dstNode = getFlowNode(edge.getEndTuple());
+      if (!reachableSet.contains(dstNode)) {
+        reachableSet.add(dstNode);
+        recurReachableSetFrom(dstNode, reachableSet);
+      }
+    }
+
+  }
+
+  public Set<NTuple<Location>> getReachableFlowTupleSet(Set<NTuple<Location>> visited, FlowNode fn) {
+
+    Set<FlowEdge> outEdgeSet = getOutEdgeSet(fn);
+
+    for (Iterator iterator = outEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge edge = (FlowEdge) iterator.next();
+
+      if (fn.getDescTuple().equals(edge.getInitTuple())) {
+        FlowNode dstNode = getFlowNode(edge.getEndTuple());
+        NTuple<Location> dstTuple = getLocationTuple(dstNode);
+
+        if (!visited.contains(dstTuple)) {
+          visited.add(dstTuple);
+          visited.addAll(getReachableFlowTupleSet(visited, dstNode));
+        }
+
+      }
+    }
+    return visited;
+  }
+
+  public NTuple<Location> getLocationTuple(NTuple<Descriptor> descTuple) {
+    return getLocationTuple(getFlowNode(descTuple));
+  }
+
+  public NTuple<Location> getLocationTuple(FlowNode fn) {
+
+    if (!mapFlowNodeToLocTuple.containsKey(fn)) {
+      NTuple<Descriptor> descTuple = fn.getDescTuple();
+      NTuple<Location> locTuple = new NTuple<Location>();
+      ClassDescriptor cd = null;
+
+      Descriptor localDesc = fn.getDescTuple().get(0);
+
+      if (fn.isIntermediate() && fn.getDescTuple().size() == 1) {
+        Location interLoc = new Location(md, localDesc.getSymbol());
+        interLoc.setLocDescriptor(localDesc);
+        locTuple.add(interLoc);
+      } else if (localDesc.getSymbol().equals(SSJavaAnalysis.TOP)) {
+        Location topLoc = new Location(md, Location.TOP);
+        topLoc.setLocDescriptor(LocationInference.TOPDESC);
+        locTuple.add(topLoc);
+      } else if (localDesc.getSymbol().equals(LocationInference.GLOBALLOC)) {
+        Location globalLoc = new Location(md, LocationInference.GLOBALLOC);
+        globalLoc.setLocDescriptor(LocationInference.GLOBALDESC);
+        locTuple.add(globalLoc);
+      } else {
+        // normal case
+        for (int i = 0; i < descTuple.size(); i++) {
+          Descriptor curDesc = descTuple.get(i);
+          Location loc;
+          if (i == 0) {
+            loc = new Location(md, curDesc.getSymbol());
+            loc.setLocDescriptor(curDesc);
+            if (curDesc instanceof VarDescriptor) {
+              cd = ((VarDescriptor) curDesc).getType().getClassDesc();
+            } else if (curDesc instanceof InterDescriptor) {
+              cd = mapIntersectionDescToEnclosingDescriptor.get(curDesc);
+            } else {
+              // otherwise it should be the last element
+              cd = null;
+            }
+          } else {
+            loc = new Location(cd, curDesc.getSymbol());
+            loc.setLocDescriptor(curDesc);
+
+            if (curDesc instanceof FieldDescriptor) {
+              cd = ((FieldDescriptor) curDesc).getType().getClassDesc();
+            } else if (curDesc instanceof LocationDescriptor) {
+              cd = ((LocationDescriptor) curDesc).getEnclosingClassDesc();
+            } else {
+              // otherwise it should be the last element of the tuple
+              cd = null;
+            }
+
+          }
+          locTuple.add(loc);
+        }
+      }
+
+      mapFlowNodeToLocTuple.put(fn, locTuple);
+    }
+    return mapFlowNodeToLocTuple.get(fn);
+  }
+
+  public Set<FlowNode> getIncomingFlowNodeSet(FlowNode node) {
+    Set<FlowNode> set = new HashSet<FlowNode>();
+    getIncomingFlowNodeSet(node, set);
+    return set;
+  }
+
+  public void getIncomingFlowNodeSet(FlowNode node, Set<FlowNode> visited) {
+
+    for (Iterator iterator = getNodeSet().iterator(); iterator.hasNext();) {
+      FlowNode curNode = (FlowNode) iterator.next();
+      Set<FlowEdge> edgeSet = getOutEdgeSet(curNode);
+
+      for (Iterator iterator2 = edgeSet.iterator(); iterator2.hasNext();) {
+        FlowEdge flowEdge = (FlowEdge) iterator2.next();
+
+        if (node.equals(getFlowNode(flowEdge.getEndTuple()))) {
+          FlowNode incomingNode = getFlowNode(flowEdge.getInitTuple());
+
+          if (incomingNode instanceof FlowReturnNode) {
+            FlowReturnNode rnode = (FlowReturnNode) incomingNode;
+            Set<NTuple<Descriptor>> nodeTupleSet = rnode.getReturnTupleSet();
+            Set<NTuple<Descriptor>> rtupleSet = getReturnTupleSet(nodeTupleSet);
+            for (Iterator iterator3 = rtupleSet.iterator(); iterator3.hasNext();) {
+              NTuple<Descriptor> nodeTuple = (NTuple<Descriptor>) iterator3.next();
+              FlowNode fn = getFlowNode(nodeTuple);
+              if (!visited.contains(fn)) {
+                visited.add(fn);
+                getIncomingFlowNodeSet(fn, visited);
+              }
+            }
+          } else {
+            if (!visited.contains(incomingNode)) {
+              visited.add(incomingNode);
+              getIncomingFlowNodeSet(incomingNode, visited);
+            }
+          }
+
+        }
+      }
+    }
+
+  }
+
+  public boolean isParameter(NTuple<Descriptor> tuple) {
+    // return true if a descriptor tuple is started with a parameter descriptor
+    Descriptor firstIdxDesc = tuple.get(0);
+    return mapParamDescToIdx.containsKey(firstIdxDesc);
+  }
+
+  public int getParamIdx(NTuple<Descriptor> tuple) {
+    Descriptor firstIdxDesc = tuple.get(0);
+    return mapParamDescToIdx.get(firstIdxDesc);
+  }
+
+  public FlowGraph clone() {
+    FlowGraph clone = new FlowGraph(md, mapParamDescToIdx);
+
+    // clone.setNodeSet(getNodeSet());
+    clone.setMapLocTupleToFlowNode(getMapLocTupleToFlowNode());
+    clone.setMapFlowNodeToLocTuple(getMapFlowNodeToLocTuple());
+    clone.setMapDescTupleToInferNode(getMapDescTupleToInferNode());
+
+    clone.setMapFlowNodeToOutEdgeSet(getMapFlowNodeToOutEdgeSet());
+    clone.setReturnNodeSet(getReturnNodeSet());
+    clone.setThisVarNode(getThisVarNode());
+
+    return clone;
+  }
+
+  public Map<FlowNode, NTuple<Location>> getMapFlowNodeToLocTuple() {
+    return mapFlowNodeToLocTuple;
+  }
+
+  public void setMapFlowNodeToLocTuple(Map<FlowNode, NTuple<Location>> in) {
+    this.mapFlowNodeToLocTuple.putAll(in);
+  }
+
+  public Map<FlowNode, Set<FlowEdge>> getMapFlowNodeToOutEdgeSet() {
+    return mapFlowNodeToOutEdgeSet;
+  }
+
+  public Set<FlowNode> getIncomingNodeSetByPrefix(Descriptor prefix) {
+
+    Set<FlowNode> incomingNodeSet = new HashSet<FlowNode>();
+
+    for (Iterator iterator = getNodeSet().iterator(); iterator.hasNext();) {
+      FlowNode curNode = (FlowNode) iterator.next();
+      Set<FlowEdge> outEdgeSet = getOutEdgeSet(curNode);
+
+      for (Iterator iterator2 = outEdgeSet.iterator(); iterator2.hasNext();) {
+        FlowEdge outEdge = (FlowEdge) iterator2.next();
+
+        if (outEdge.getEndTuple().startsWith(prefix)) {
+          incomingNodeSet.add(curNode);
+          recurIncomingNodeSetByPrefix(prefix, curNode, incomingNodeSet);
+
+        }
+
+      }
+    }
+
+    return incomingNodeSet;
+
+  }
+
+  private void recurIncomingNodeSetByPrefix(Descriptor prefix, FlowNode node, Set<FlowNode> visited) {
+
+    Set<FlowEdge> inEdgeSet = getInEdgeSet(node);
+
+    for (Iterator iterator = inEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge inEdge = (FlowEdge) iterator.next();
+
+      FlowNode inNode = getFlowNode(inEdge.getInitTuple());
+      if (!inEdge.getInitTuple().startsWith(prefix) && !visited.contains(inNode)) {
+        visited.add(inNode);
+        recurIncomingNodeSetByPrefix(prefix, inNode, visited);
+      }
+    }
+
+  }
+
+  public void setMapFlowNodeToOutEdgeSet(Map<FlowNode, Set<FlowEdge>> inMap) {
+    Set<FlowNode> keySet = inMap.keySet();
+    for (Iterator iterator = keySet.iterator(); iterator.hasNext();) {
+      FlowNode key = (FlowNode) iterator.next();
+      Set<FlowEdge> newEdgeSet = new HashSet<FlowEdge>();
+      newEdgeSet.addAll(inMap.get(key));
+      mapFlowNodeToOutEdgeSet.put(key, newEdgeSet);
+    }
+  }
+
+  private void drawEdges(FlowNode node, BufferedWriter bw, Set<FlowNode> addedNodeSet,
+      Set<FlowEdge> addedEdgeSet) throws IOException {
+
+    Set<FlowEdge> edgeSet = getOutEdgeSet(node);
+
+    for (Iterator<FlowEdge> iterator = edgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge flowEdge = iterator.next();
+
+      FlowNode u = flowEdge.getSrc();
+      FlowNode v = flowEdge.getDst();
+
+      if (u.getDescTuple().equals(flowEdge.getInitTuple())
+          && v.getDescTuple().equals(flowEdge.getEndTuple())) {
+        // only draw an edge of the actual value flow
+
+        if (!addedEdgeSet.contains(flowEdge)) {
+
+          if (!addedNodeSet.contains(u)) {
+            drawNode(u, bw);
+            addedNodeSet.add(u);
+          }
+          if (!addedNodeSet.contains(v)) {
+            drawNode(v, bw);
+            addedNodeSet.add(v);
+          }
+
+          bw.write("" + u.getID() + " -> " + v.getID() + ";\n");
+          addedEdgeSet.add(flowEdge);
+        }
+      }
+
+    }
+
+  }
+
+  private void drawNode(FlowNode node, BufferedWriter bw) throws IOException {
+    if (node instanceof FlowReturnNode) {
+      FlowReturnNode rnode = (FlowReturnNode) node;
+      bw.write(node.getID() + " [label=\"" + node.getPrettyID() + "\"]" + ";\n");
+    } else {
+      bw.write(node.getID() + " [label=\"" + node.getPrettyID() + "\"]" + ";\n");
+    }
+
+  }
+
+  public void writeGraph() throws java.io.IOException {
+    writeGraph("");
+  }
+
+  public void writeGraph(String suffix) throws java.io.IOException {
+
+    String graphName = "flowgraph_" + md.toString() + suffix;
+    graphName = graphName.replaceAll("[\\W]", "");
+
+    BufferedWriter bw = new BufferedWriter(new FileWriter(graphName + ".dot"));
+    bw.write("digraph " + graphName + " {\n");
+    bw.write("compound=true;\n");
+
+    // then visit every flow node
+
+    // Iterator<FlowNode> iter = nodeSet.iterator();
+    Iterator<FlowNode> iter = getNodeSet().iterator();
+
+    Set<FlowEdge> addedEdgeSet = new HashSet<FlowEdge>();
+    Set<FlowNode> addedNodeSet = new HashSet<FlowNode>();
+
+    while (iter.hasNext()) {
+      FlowNode node = iter.next();
+
+      if (node.getDescTuple().size() == 1) {
+        // here, we just care about the local variable
+        if (node.getFieldNodeSet().size() > 0) {
+          drawSubgraph(node, bw, addedEdgeSet);
+        }
+      }
+      drawEdges(node, bw, addedNodeSet, addedEdgeSet);
+
+    }
+
+    bw.write("}\n");
+    bw.close();
+
+  }
+
+  public boolean constainsNode(FlowNode node) {
+    return getNodeSet().contains(node);
+  }
+
+  private void drawSubgraph(FlowNode node, BufferedWriter bw, Set<FlowEdge> addedSet)
+      throws IOException {
+
+    bw.write("subgraph cluster_" + node.getID() + "{\n");
+    bw.write("label=\"" + node.getPrettyID() + "\";\n");
+
+    Set<FlowNode> fieldNodeSet = node.getFieldNodeSet();
+    for (Iterator iterator = fieldNodeSet.iterator(); iterator.hasNext();) {
+      FlowNode fieldNode = (FlowNode) iterator.next();
+      if (fieldNode.getFieldNodeSet().size() > 0) {
+        drawSubgraph(fieldNode, bw, addedSet);
+      } else {
+        Descriptor desc = fieldNode.getDescTuple().getLastElement();
+        if (desc instanceof VarDescriptor) {
+          VarDescriptor varDesc = (VarDescriptor) desc;
+          if (varDesc.getType().isPrimitive()) {
+            bw.write(fieldNode.getID() + " [label=\"" + fieldNode.getPrettyID() + "\"];\n");
+          }
+        } else if (desc instanceof FieldDescriptor) {
+          FieldDescriptor fieldDesc = (FieldDescriptor) desc;
+          if (fieldDesc.getType().isPrimitive()) {
+            bw.write(fieldNode.getID() + " [label=\"" + fieldNode.getPrettyID() + "\"];\n");
+          }
+        }
+      }
+    }
+
+    bw.write("}\n");
+  }
+
+  public void removeEdge(NTuple<Descriptor> from, NTuple<Descriptor> to) {
+
+    Set<FlowEdge> toberemoved = new HashSet<FlowEdge>();
+    Set<FlowEdge> edgeSet = getOutEdgeSet(getFlowNode(from));
+
+    for (Iterator iterator = edgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge flowEdge = (FlowEdge) iterator.next();
+      if (flowEdge.getInitTuple().equals(from) && flowEdge.getEndTuple().equals(to)) {
+        toberemoved.add(flowEdge);
+      }
+    }
+
+    edgeSet.removeAll(toberemoved);
+
+  }
+
+  public void removeNode(FlowNode node) {
+
+    NTuple<Descriptor> tuple = node.getCurrentDescTuple();
+
+    Set<FlowEdge> inEdgeSet = getInEdgeSet(node);
+    for (Iterator iterator = inEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge flowEdge = (FlowEdge) iterator.next();
+      if (flowEdge.getEndTuple().equals(tuple)) {
+
+        Set<FlowEdge> outSet = getOutEdgeSet(getFlowNode(flowEdge.getInitTuple()));
+        Set<FlowEdge> toberemoved = new HashSet<FlowEdge>();
+        for (Iterator iterator2 = outSet.iterator(); iterator2.hasNext();) {
+          FlowEdge outEdge = (FlowEdge) iterator2.next();
+          if (outEdge.getEndTuple().equals(tuple)) {
+            toberemoved.add(outEdge);
+          }
+        }
+        outSet.removeAll(toberemoved);
+      }
+    }
+
+    Set<FlowEdge> outEdgeSet = getOutEdgeSet(node);
+    for (Iterator iterator = outEdgeSet.iterator(); iterator.hasNext();) {
+      FlowEdge flowEdge = (FlowEdge) iterator.next();
+      if (flowEdge.getInitTuple().equals(tuple)) {
+
+        Set<FlowEdge> inSet = getInEdgeSet(getFlowNode(flowEdge.getEndTuple()));
+        Set<FlowEdge> toberemoved = new HashSet<FlowEdge>();
+        for (Iterator iterator2 = inSet.iterator(); iterator2.hasNext();) {
+          FlowEdge inEdge = (FlowEdge) iterator2.next();
+          if (inEdge.getInitTuple().equals(tuple)) {
+            toberemoved.add(inEdge);
+          }
+        }
+        inSet.removeAll(toberemoved);
+      }
+    }
+
+    for (Iterator iterator = getNodeSet().iterator(); iterator.hasNext();) {
+      FlowNode flowNode = (FlowNode) iterator.next();
+      Set<FlowEdge> outSet = getOutEdgeSet(flowNode);
+      Set<FlowEdge> toberemoved = new HashSet<FlowEdge>();
+      for (Iterator iterator2 = outSet.iterator(); iterator2.hasNext();) {
+        FlowEdge flowEdge = (FlowEdge) iterator2.next();
+        if (flowEdge.getInitTuple().equals(tuple) || flowEdge.getEndTuple().equals(tuple)) {
+          toberemoved.add(flowEdge);
+        }
+      }
+      outSet.removeAll(toberemoved);
+    }
+
+    mapFlowNodeToOutEdgeSet.remove(node);
+    mapFlowNodeToInEdgeSet.remove(node);
+    System.out.println("REMOVING NODE=" + mapDescTupleToInferNode.get(tuple) + " from tuple="
+        + tuple);
+    mapDescTupleToInferNode.remove(tuple);
+    System.out.println("mapDescTupleToInferNode=" + mapDescTupleToInferNode);
+  }
+}
\ No newline at end of file