First bug fix is that the "unshadow" token conversion mistakenly transforms the oldes...
[IRC.git] / Robust / src / Analysis / OwnershipAnalysis / OwnershipGraph.java
index 72cc326ba8762194b302bc316e82735310e15602..a3a65298f549ed3d7e5c3c5059461d7c93f73fa1 100644 (file)
@@ -8,6 +8,7 @@ import java.io.*;
 public class OwnershipGraph {
 
   private int allocationDepth;
+  private TypeUtil typeUtil;
 
   // there was already one other very similar reason
   // for traversing heap nodes that is no longer needed
@@ -30,8 +31,9 @@ public class OwnershipGraph {
 
 
 
-  public OwnershipGraph(int allocationDepth) {
+  public OwnershipGraph(int allocationDepth, TypeUtil typeUtil) {
     this.allocationDepth = allocationDepth;
+    this.typeUtil        = typeUtil;
 
     id2hrn         = new Hashtable<Integer,        HeapRegionNode>();
     td2ln          = new Hashtable<TempDescriptor, LabelNode     >();
@@ -887,7 +889,6 @@ public class OwnershipGraph {
                                 FlatMethod fm,
                                 OwnershipGraph ogCallee) {
 
-
     // define rewrite rules and other structures to organize
     // data by parameter/argument index
     Hashtable<Integer, ReachabilitySet> paramIndex2rewriteH =
@@ -988,7 +989,7 @@ public class OwnershipGraph {
       if( isStatic ) {
        argTemp_i = fc.getArg(paramIndex);
       } else {
-       if( paramIndex == 0 ) {
+       if( paramIndex.equals( 0 ) ) {
          argTemp_i = fc.getThis();
        } else {
          argTemp_i = fc.getArg(paramIndex - 1);
@@ -1010,9 +1011,11 @@ public class OwnershipGraph {
       Iterator<ReferenceEdge> edgeItr = argLabel_i.iteratorToReferencees();
       while( edgeItr.hasNext() ) {
        ReferenceEdge edge = edgeItr.next();
-       D_i = D_i.union(edge.getBeta() );
+       D_i = D_i.union(edge.getBeta());
       }
+
       D_i = D_i.exhaustiveArityCombinations();
+
       paramIndex2rewriteD.put(paramIndex, D_i);
     }
 
@@ -1065,13 +1068,16 @@ public class OwnershipGraph {
       while( hrnItr.hasNext() ) {
        HeapRegionNode hrn = hrnItr.next();
 
-       rewriteCallerNodeAlpha(fm.numParameters(),
-                              index,
-                              hrn,
-                              paramIndex2rewriteH,
-                              paramIndex2rewriteD,
-                              paramIndex2paramToken,
-                              paramIndex2paramTokenStar);
+       rewriteCallerReachability(index,
+                                 hrn,
+                                 null,
+                                 paramIndex2rewriteH.get(index),
+                                 paramIndex2rewriteD,
+                                 paramIndex2paramToken.get(index),
+                                 paramToken2paramIndex,
+                                 paramTokenStar2paramIndex,
+                                 false,
+                                 null);
 
        nodesWithNewAlpha.add(hrn);
 
@@ -1105,43 +1111,43 @@ public class OwnershipGraph {
        }
       }
 
-
       // update reachable edges
       Iterator<ReferenceEdge> edgeReachableItr = edgesReachable.iterator();
       while( edgeReachableItr.hasNext() ) {
        ReferenceEdge edgeReachable = edgeReachableItr.next();
 
-       rewriteCallerEdgeBeta(fm.numParameters(),
-                             index,
-                             edgeReachable,
-                             paramIndex2rewriteJ,
-                             paramIndex2rewriteD,
-                             paramIndex2paramToken,
-                             paramIndex2paramTokenStar,
-                             false,
-                             null);
+       rewriteCallerReachability(index,
+                                 null,
+                                 edgeReachable,
+                                 paramIndex2rewriteJ.get(index),
+                                 paramIndex2rewriteD,
+                                 paramIndex2paramToken.get(index),
+                                 paramToken2paramIndex,
+                                 paramTokenStar2paramIndex,
+                                 false,
+                                 null);
 
        edgesWithNewBeta.add(edgeReachable);
       }
 
-
       // update upstream edges
-      Hashtable<ReferenceEdge, ChangeTupleSet> edgeUpstreamPlannedChanges
-      = new Hashtable<ReferenceEdge, ChangeTupleSet>();
+      Hashtable<ReferenceEdge, ChangeTupleSet> edgeUpstreamPlannedChanges =
+       new Hashtable<ReferenceEdge, ChangeTupleSet>();
 
       Iterator<ReferenceEdge> edgeUpstreamItr = edgesUpstream.iterator();
       while( edgeUpstreamItr.hasNext() ) {
        ReferenceEdge edgeUpstream = edgeUpstreamItr.next();
 
-       rewriteCallerEdgeBeta(fm.numParameters(),
-                             index,
-                             edgeUpstream,
-                             paramIndex2rewriteK,
-                             paramIndex2rewriteD,
-                             paramIndex2paramToken,
-                             paramIndex2paramTokenStar,
-                             true,
-                             edgeUpstreamPlannedChanges);
+       rewriteCallerReachability(index,
+                                 null,
+                                 edgeUpstream,
+                                 paramIndex2rewriteK.get(index),
+                                 paramIndex2rewriteD,
+                                 paramIndex2paramToken.get(index),
+                                 paramToken2paramIndex,
+                                 paramTokenStar2paramIndex,
+                                 true,
+                                 edgeUpstreamPlannedChanges);
 
        edgesWithNewBeta.add(edgeUpstream);
       }
@@ -1164,7 +1170,6 @@ public class OwnershipGraph {
     }
 
 
-
     // verify the existence of allocation sites and their
     // shadows from the callee in the context of this caller graph
     // then map allocated nodes of callee onto the caller shadows
@@ -1191,13 +1196,16 @@ public class OwnershipGraph {
       // so rewrite and immediately commit--and they don't belong
       // to a particular parameter, so use a bogus param index
       // that pulls a self-rewrite out of H
-      rewriteCallerNodeAlpha(fm.numParameters(),
-                             bogusIndex,
-                             hrnShadowSummary,
-                             paramIndex2rewriteH,
-                             paramIndex2rewriteD,
-                             paramIndex2paramToken,
-                             paramIndex2paramTokenStar);
+      rewriteCallerReachability(bogusIndex,
+                               hrnShadowSummary,
+                               null,
+                               hrnShadowSummary.getAlpha(),
+                               paramIndex2rewriteD,
+                               bogusToken,
+                               paramToken2paramIndex,
+                               paramTokenStar2paramIndex,
+                               false,
+                               null);
 
       hrnShadowSummary.applyAlphaNew();
 
@@ -1219,13 +1227,16 @@ public class OwnershipGraph {
        HeapRegionNode hrnIthCallee = ogCallee.id2hrn.get(idIth);
        hrnIthShadow.setAlpha(toShadowTokens(ogCallee, hrnIthCallee.getAlpha() ) );
 
-       rewriteCallerNodeAlpha(fm.numParameters(),
-                              bogusIndex,
-                              hrnIthShadow,
-                              paramIndex2rewriteH,
-                              paramIndex2rewriteD,
-                              paramIndex2paramToken,
-                              paramIndex2paramTokenStar);
+       rewriteCallerReachability(bogusIndex,
+                                 hrnIthShadow,
+                                 null,
+                                 hrnIthShadow.getAlpha(),
+                                 paramIndex2rewriteD,
+                                 bogusToken,
+                                 paramToken2paramIndex,
+                                 paramTokenStar2paramIndex,
+                                 false,
+                                 null);
 
        hrnIthShadow.applyAlphaNew();
       }
@@ -1267,15 +1278,16 @@ public class OwnershipGraph {
                                                                    false,
                                                                    toShadowTokens(ogCallee, edgeCallee.getBeta() )
                                                                    );
-         rewriteCallerEdgeBeta(fm.numParameters(),
-                               bogusIndex,
-                               edgeNewInCallerTemplate,
-                               paramIndex2rewriteJ,
-                               paramIndex2rewriteD,
-                               paramIndex2paramToken,
-                               paramIndex2paramTokenStar,
-                               false,
-                               null);
+         rewriteCallerReachability(bogusIndex,
+                                   null,
+                                   edgeNewInCallerTemplate,
+                                   edgeNewInCallerTemplate.getBeta(),
+                                   paramIndex2rewriteD,
+                                   bogusToken,
+                                   paramToken2paramIndex,
+                                   paramTokenStar2paramIndex,
+                                   false,
+                                   null);
 
          edgeNewInCallerTemplate.applyBetaNew();
 
@@ -1292,46 +1304,26 @@ public class OwnershipGraph {
            getHRNSetThatPossiblyMapToCalleeHRN(ogCallee,
                                                edgeCallee.getDst(),
                                                paramIndex2reachableCallerNodes);
-         
+
 
          // make every possible pair of {srcSet} -> {dstSet} edges in the caller
          Iterator srcItr = possibleCallerSrcs.iterator();
          while( srcItr.hasNext() ) {
            HeapRegionNode src = (HeapRegionNode) srcItr.next();
 
-           // check that if this source node has a definite type that
-           // it also has the appropriate field, otherwise prune this
-           AllocationSite asSrc = src.getAllocationSite();
-           if( asSrc != null ) {
-             boolean foundField = false;             
-             Iterator fieldsSrcItr = asSrc.getType().getClassDesc().getFields();
-             while( fieldsSrcItr.hasNext() ) {
-               FieldDescriptor fd = (FieldDescriptor) fieldsSrcItr.next();
-               if( fd == edgeCallee.getFieldDesc() ) {
-                 foundField = true;
-                 break;
-               }
-             }
-             if( !foundField ) {
-               // prune this source node possibility
-               continue;
-             }
+           if( !hasMatchingField(src, edgeCallee) ) {
+             // prune this source node possibility
+             continue;
            }
 
            Iterator dstItr = possibleCallerDsts.iterator();
            while( dstItr.hasNext() ) {
              HeapRegionNode dst = (HeapRegionNode) dstItr.next();
 
-             // check if this dst node has a definite type and
-             // if it matches the callee edge
-             AllocationSite asDst = dst.getAllocationSite();
-             if( asDst != null && edgeCallee.getFieldDesc() != null ) {
-               if( asDst.getType() == null && edgeCallee.getFieldDesc().getType() != null ) { continue; }
-               if( asDst.getType() != null && edgeCallee.getFieldDesc().getType() == null ) { continue; }
-               if( asDst.getType() != null && edgeCallee.getFieldDesc().getType() != null ) {
-                 if( !asDst.getType().equals( edgeCallee.getFieldDesc().getType() ) ) { continue; }
-               }
-             }       
+             if( !hasMatchingType(edgeCallee, dst) ) {
+               // prune
+               continue;
+             }
 
              // otherwise the caller src and dst pair can match the edge, so make it
              ReferenceEdge edgeNewInCaller = edgeNewInCallerTemplate.copy();
@@ -1353,11 +1345,11 @@ public class OwnershipGraph {
     }
 
 
-
     // return value may need to be assigned in caller
-    if( fc.getReturnTemp() != null ) {
+    TempDescriptor returnTemp = fc.getReturnTemp();
+    if( returnTemp != null && !returnTemp.getType().isImmutable() ) {
 
-      LabelNode lnLhsCaller = getLabelNodeFromTemp(fc.getReturnTemp() );
+      LabelNode lnLhsCaller = getLabelNodeFromTemp(returnTemp);
       clearReferenceEdgesFrom(lnLhsCaller, null, true);
 
       LabelNode lnReturnCallee = ogCallee.getLabelNodeFromTemp(tdReturn);
@@ -1366,21 +1358,22 @@ public class OwnershipGraph {
        ReferenceEdge edgeCallee = edgeCalleeItr.next();
 
        ReferenceEdge edgeNewInCallerTemplate = new ReferenceEdge(null,
-                                                                 null,
-                                                                 edgeCallee.getFieldDesc(),
-                                                                 false,
-                                                                 toShadowTokens(ogCallee, edgeCallee.getBeta() )
-                                                                 );
-       rewriteCallerEdgeBeta(fm.numParameters(),
-                             bogusIndex,
-                             edgeNewInCallerTemplate,
-                             paramIndex2rewriteJ,
-                             paramIndex2rewriteD,
-                             paramIndex2paramToken,
-                             paramIndex2paramTokenStar,
-                             false,
-                             null);
-       
+                                                                 null,
+                                                                 edgeCallee.getFieldDesc(),
+                                                                 false,
+                                                                 toShadowTokens(ogCallee, edgeCallee.getBeta() )
+                                                                 );
+       rewriteCallerReachability(bogusIndex,
+                                 null,
+                                 edgeNewInCallerTemplate,
+                                 edgeNewInCallerTemplate.getBeta(),
+                                 paramIndex2rewriteD,
+                                 bogusToken,
+                                 paramToken2paramIndex,
+                                 paramTokenStar2paramIndex,
+                                 false,
+                                 null);
+
        edgeNewInCallerTemplate.applyBetaNew();
 
 
@@ -1392,19 +1385,11 @@ public class OwnershipGraph {
        Iterator<HeapRegionNode> itrHrn = assignCallerRhs.iterator();
        while( itrHrn.hasNext() ) {
          HeapRegionNode hrnCaller = itrHrn.next();
-        
-         // check if this dst node has a definite type and
-         // if it matches the callee edge
-         // check if this dst node has a definite type and
-         // if it matches the callee edge
-         AllocationSite asDst = hrnCaller.getAllocationSite();
-         if( asDst != null && edgeCallee.getFieldDesc() != null ) {
-           if( asDst.getType() == null && edgeCallee.getFieldDesc().getType() != null ) { continue; }
-           if( asDst.getType() != null && edgeCallee.getFieldDesc().getType() == null ) { continue; }
-           if( asDst.getType() != null && edgeCallee.getFieldDesc().getType() != null ) {
-             if( !asDst.getType().equals( edgeCallee.getFieldDesc().getType() ) ) { continue; }
-           }
-         }           
+
+         if( !hasMatchingType(edgeCallee, hrnCaller) ) {
+           // prune
+           continue;
+         }
 
          // otherwise caller node can match callee edge, so make it
          ReferenceEdge edgeNewInCaller = edgeNewInCallerTemplate.copy();
@@ -1413,18 +1398,18 @@ public class OwnershipGraph {
 
          ReferenceEdge edgeExisting = lnLhsCaller.getReferenceTo(hrnCaller, edgeNewInCaller.getFieldDesc() );
          if( edgeExisting == null ) {
+
            // if this edge doesn't exist in the caller, create it
            addReferenceEdge(lnLhsCaller, hrnCaller, edgeNewInCaller);
          } else {
            // if it already exists, merge with it
            edgeExisting.setBeta(edgeExisting.getBeta().union(edgeNewInCaller.getBeta() ) );
-         }      
+         }
        }
       }
     }
 
 
-
     // merge the shadow nodes of allocation sites back down to normal capacity
     Iterator<AllocationSite> allocItr = ogCallee.allocationSites.iterator();
     while( allocItr.hasNext() ) {
@@ -1494,6 +1479,67 @@ public class OwnershipGraph {
   }
 
 
+  protected boolean hasMatchingField(HeapRegionNode src, ReferenceEdge edge) {
+
+    // if no allocation site, then it's a match-everything region
+    AllocationSite asSrc = src.getAllocationSite();
+    if( asSrc == null ) {
+      return true;
+    }
+
+    TypeDescriptor tdSrc = asSrc.getType();
+    assert tdSrc != null;
+
+    // if it's not a class, it doesn't have any fields to match
+    if( !tdSrc.isClass() ) {
+      return false;
+    }
+
+    Iterator fieldsSrcItr = tdSrc.getClassDesc().getFields();
+    while( fieldsSrcItr.hasNext() ) {
+      FieldDescriptor fd = (FieldDescriptor) fieldsSrcItr.next();
+      if( fd == edge.getFieldDesc() ) {
+       return true;
+      }
+    }
+
+    // otherwise it is a class with fields
+    // but we didn't find a match
+    return false;
+  }
+
+
+  protected boolean hasMatchingType(ReferenceEdge edge, HeapRegionNode dst) {
+
+    // if the region has no type, matches everything
+    AllocationSite asDst = dst.getAllocationSite();
+    if( asDst == null ) {
+      return true;
+    }
+
+    TypeDescriptor tdDst = asDst.getType();
+    assert tdDst != null;
+
+    // if the type is not a class don't match because
+    // primitives are copied, no memory aliases
+    ClassDescriptor cdDst = tdDst.getClassDesc();
+    if( cdDst == null ) {
+      return false;
+    }
+
+    // if the field is null, it matches everything
+    FieldDescriptor fd = edge.getFieldDesc();
+    if( fd == null ) {
+      return true;
+    }
+    TypeDescriptor tdFd = fd.getType();
+    assert tdFd != null;
+
+    return typeUtil.isSuperorType(tdFd, tdDst);
+  }
+
+
+
   protected void unshadowTokens(AllocationSite as, ReferenceEdge edge) {
     edge.setBeta(edge.getBeta().unshadowTokens(as) );
   }
@@ -1519,198 +1565,166 @@ public class OwnershipGraph {
   }
 
 
-  private void rewriteCallerNodeAlpha(int numParameters,
-                                      Integer paramIndex,
-                                      HeapRegionNode hrn,
-                                      Hashtable<Integer, ReachabilitySet> paramIndex2rewriteH,
-                                      Hashtable<Integer, ReachabilitySet> paramIndex2rewriteD,
-                                      Hashtable<Integer, TokenTuple> paramIndex2paramToken,
-                                      Hashtable<Integer, TokenTuple> paramIndex2paramTokenStar) {
+  private void rewriteCallerReachability(Integer paramIndex,
+                                        HeapRegionNode hrn,
+                                        ReferenceEdge edge,
+                                        ReachabilitySet rules,
+                                        Hashtable<Integer, ReachabilitySet> paramIndex2rewriteD,
+                                        TokenTuple p_i,
+                                        Hashtable<TokenTuple, Integer> paramToken2paramIndex,
+                                        Hashtable<TokenTuple, Integer> paramTokenStar2paramIndex,
+                                        boolean makeChangeSet,
+                                        Hashtable<ReferenceEdge, ChangeTupleSet> edgePlannedChanges) {
+    assert (hrn == null && edge != null) || 
+           (hrn != null && edge == null);
 
-    ReachabilitySet rules = paramIndex2rewriteH.get(paramIndex);
     assert rules != null;
+    assert p_i != null;
 
-    TokenTuple tokenToRewrite = paramIndex2paramToken.get(paramIndex);
-    assert tokenToRewrite != null;
-
-    ReachabilitySet r0 = new ReachabilitySet().makeCanonical();
-    Iterator<TokenTupleSet> ttsItr = rules.iterator();
-    while( ttsItr.hasNext() ) {
-      TokenTupleSet tts = ttsItr.next();
-      r0 = r0.union(tts.rewriteToken(tokenToRewrite,
-                                     hrn.getAlpha(),
-                                     false,
-                                     null) );
-    }
-
-    ReachabilitySet r1 = new ReachabilitySet().makeCanonical();
-    ttsItr = r0.iterator();
-    while( ttsItr.hasNext() ) {
-      TokenTupleSet tts = ttsItr.next();
-      r1 = r1.union(rewriteDpass(numParameters,
-                                 paramIndex,
-                                 tts,
-                                 paramIndex2rewriteD,
-                                 paramIndex2paramToken,
-                                 paramIndex2paramTokenStar) );
+    ReachabilitySet callerReachabilityCurrent;
+    if( hrn == null ) {
+      callerReachabilityCurrent = edge.getBeta();
+    } else {
+      callerReachabilityCurrent = hrn.getAlpha();
     }
 
-    hrn.setAlphaNew(hrn.getAlphaNew().union(r1) );
-  }
-
+    ReachabilitySet callerReachabilityNew = new ReachabilitySet().makeCanonical();
 
-  private void rewriteCallerEdgeBeta(int numParameters,
-                                     Integer paramIndex,
-                                     ReferenceEdge edge,
-                                     Hashtable<Integer, ReachabilitySet> paramIndex2rewriteJorK,
-                                     Hashtable<Integer, ReachabilitySet> paramIndex2rewriteD,
-                                     Hashtable<Integer, TokenTuple> paramIndex2paramToken,
-                                     Hashtable<Integer, TokenTuple> paramIndex2paramTokenStar,
-                                     boolean makeChangeSet,
-                                     Hashtable<ReferenceEdge, ChangeTupleSet> edgePlannedChanges) {
+    // for initializing structures in this method
+    TokenTupleSet ttsEmpty = new TokenTupleSet().makeCanonical();
 
-    ReachabilitySet rules = paramIndex2rewriteJorK.get(paramIndex);
-    assert rules != null;
+    // use this to construct a change set if required; the idea is to
+    // map every partially rewritten token tuple set to the set of 
+    // caller-context token tuple sets that were used to generate it
+    Hashtable<TokenTupleSet, HashSet<TokenTupleSet> > rewritten2source =
+      new Hashtable<TokenTupleSet, HashSet<TokenTupleSet> >();
+    rewritten2source.put(ttsEmpty, new HashSet<TokenTupleSet>() );
 
-    TokenTuple tokenToRewrite = paramIndex2paramToken.get(paramIndex);
-    assert tokenToRewrite != null;
 
-    ChangeTupleSet cts0 = new ChangeTupleSet().makeCanonical();
+    Iterator<TokenTupleSet> rulesItr = rules.iterator();
+    while(rulesItr.hasNext()) {
+      TokenTupleSet rule = rulesItr.next();
 
-    Iterator<TokenTupleSet> ttsItr = rules.iterator();
-    while( ttsItr.hasNext() ) {
-      TokenTupleSet tts = ttsItr.next();
+      ReachabilitySet rewrittenRule = new ReachabilitySet(ttsEmpty).makeCanonical();
 
-      Hashtable<TokenTupleSet, TokenTupleSet> forChangeSet =
-        new Hashtable<TokenTupleSet, TokenTupleSet>();
+      Iterator<TokenTuple> ruleItr = rule.iterator();
+      while(ruleItr.hasNext()) {
+       TokenTuple ttCallee = ruleItr.next();
 
-      ReachabilitySet rTemp = tts.rewriteToken(tokenToRewrite,
-                                               edge.getBeta(),
-                                               true,
-                                               forChangeSet);
+       // compute the possibilities for rewriting this callee token
+       ReachabilitySet ttCalleeRewrites = null;
+       boolean callerSourceUsed = false;
 
-      Iterator fcsItr = forChangeSet.entrySet().iterator();
-      while( fcsItr.hasNext() ) {
-       Map.Entry me = (Map.Entry)fcsItr.next();
-       TokenTupleSet ttsMatch = (TokenTupleSet) me.getKey();
-       TokenTupleSet ttsAdd   = (TokenTupleSet) me.getValue();
-
-       ChangeTuple ct = new ChangeTuple(ttsMatch,
-                                        ttsAdd
-                                        ).makeCanonical();
-
-       cts0 = cts0.union(ct);
-      }
-    }
-
-
-    ReachabilitySet r1 = new ReachabilitySet().makeCanonical();
-    ChangeTupleSet cts1 = new ChangeTupleSet().makeCanonical();
-
-    Iterator<ChangeTuple> ctItr = cts0.iterator();
-    while( ctItr.hasNext() ) {
-      ChangeTuple ct = ctItr.next();
-
-      ReachabilitySet rTemp = rewriteDpass(numParameters,
-                                           paramIndex,
-                                           ct.getSetToAdd(),
-                                           paramIndex2rewriteD,
-                                           paramIndex2paramToken,
-                                           paramIndex2paramTokenStar
-                                           ).makeCanonical();
-      r1 = r1.union(rTemp);
+       if( ttCallee.equals( p_i ) ) {
+         // replace the arity-one token of the current parameter with the reachability
+         // information from the caller edge
+         ttCalleeRewrites = callerReachabilityCurrent;
+         callerSourceUsed = true;
+         
+       } else if( paramToken2paramIndex.containsKey( ttCallee ) ||
+                  paramTokenStar2paramIndex.containsKey( ttCallee ) ) {
+
+         // this token is another callee parameter, or any ARITY_MANY callee parameter,
+         // so rewrite it with the D rules for that parameter
+         Integer paramIndex_j;
+         if( paramToken2paramIndex.containsKey( ttCallee ) ) {
+           paramIndex_j = paramToken2paramIndex.get( ttCallee );
+         } else {
+           paramIndex_j = paramTokenStar2paramIndex.get( ttCallee );
+         }
 
-      if( makeChangeSet ) {
-       assert edgePlannedChanges != null;
+         ttCalleeRewrites = paramIndex2rewriteD.get( paramIndex_j );
+         assert ttCalleeRewrites != null;
 
-       Iterator<TokenTupleSet> ttsTempItr = rTemp.iterator();
-       while( ttsTempItr.hasNext() ) {
-         TokenTupleSet tts = ttsTempItr.next();
+       } else {
 
-         ChangeTuple ctFinal = new ChangeTuple(ct.getSetToMatch(),
-                                               tts
-                                               ).makeCanonical();
+         // otherwise there's no need for a rewrite, just pass this one on
+         TokenTupleSet ttsCaller = new TokenTupleSet(ttCallee).makeCanonical();
+         ttCalleeRewrites = new ReachabilitySet(ttsCaller).makeCanonical();
+       }
+       
+       // branch every version of the working rewritten rule with 
+       // the possibilities for rewriting the current callee token
+       ReachabilitySet rewrittenRuleWithTTCallee = new ReachabilitySet().makeCanonical();
+
+       Iterator<TokenTupleSet> rewrittenRuleItr = rewrittenRule.iterator();
+       while( rewrittenRuleItr.hasNext() ) {
+         TokenTupleSet ttsRewritten = rewrittenRuleItr.next();
+
+         Iterator<TokenTupleSet> ttCalleeRewritesItr = ttCalleeRewrites.iterator();
+         while( ttCalleeRewritesItr.hasNext() ) {
+           TokenTupleSet ttsBranch = ttCalleeRewritesItr.next();
+
+           TokenTupleSet ttsRewrittenNext = ttsRewritten.unionUpArity( ttsBranch );
+
+           if( makeChangeSet ) {
+             // in order to keep the list of source token tuple sets
+             // start with the sets used to make the partially rewritten
+             // rule up to this point
+             HashSet<TokenTupleSet> sourceSets = rewritten2source.get( ttsRewritten );
+             assert sourceSets != null;
+
+             // make a shallow copy for possible modification
+             sourceSets = (HashSet<TokenTupleSet>) sourceSets.clone();
+
+             // if we used something from the caller to rewrite it, remember
+             if( callerSourceUsed ) {
+               sourceSets.add( ttsBranch );
+             }
 
-         cts1 = cts1.union(ctFinal);
+             // set mapping for the further rewritten rule
+             rewritten2source.put( ttsRewrittenNext, sourceSets );
+           }
+         
+           rewrittenRuleWithTTCallee = 
+             rewrittenRuleWithTTCallee.union( ttsRewrittenNext );
+         }
        }
+
+       // now the rewritten rule's possibilities have been extended by
+       // rewriting the current callee token, remember result
+       rewrittenRule = rewrittenRuleWithTTCallee;
       }
-    }
 
-    if( makeChangeSet ) {
-      edgePlannedChanges.put(edge, cts1);
+      // the rule has been entirely rewritten into the caller context
+      // now, so add it to the new reachability information
+      callerReachabilityNew =
+       callerReachabilityNew.union( rewrittenRule );
     }
 
-    edge.setBetaNew(edge.getBetaNew().union(r1) );
-  }
-
-
-  private ReachabilitySet rewriteDpass(int numParameters,
-                                       Integer paramIndex,
-                                       TokenTupleSet ttsIn,
-                                       Hashtable<Integer, ReachabilitySet> paramIndex2rewriteD,
-                                       Hashtable<Integer, TokenTuple> paramIndex2paramToken,
-                                       Hashtable<Integer, TokenTuple> paramIndex2paramTokenStar) {
-
-    ReachabilitySet rsOut = new ReachabilitySet().makeCanonical();
-
-    boolean rewritten = false;
-
-    for( int j = 0; j < numParameters; ++j ) {
-      Integer paramIndexJ = new Integer(j);
-      ReachabilitySet D_j = paramIndex2rewriteD.get(paramIndexJ);
-      assert D_j != null;
-
-      if( paramIndexJ != paramIndex ) {
-       TokenTuple tokenToRewriteJ = paramIndex2paramToken.get(paramIndexJ);
-       assert tokenToRewriteJ != null;
-       if( ttsIn.containsTuple(tokenToRewriteJ) ) {
-         ReachabilitySet r = ttsIn.rewriteToken(tokenToRewriteJ,
-                                                D_j,
-                                                false,
-                                                null);
-         Iterator<TokenTupleSet> ttsItr = r.iterator();
-         while( ttsItr.hasNext() ) {
-           TokenTupleSet tts = ttsItr.next();
-           rsOut = rsOut.union(rewriteDpass(numParameters,
-                                            paramIndex,
-                                            tts,
-                                            paramIndex2rewriteD,
-                                            paramIndex2paramToken,
-                                            paramIndex2paramTokenStar) );
-           rewritten = true;
-         }
+    if( makeChangeSet ) {
+      ChangeTupleSet callerChangeSet = new ChangeTupleSet().makeCanonical();
+      
+      // each possibility for the final reachability should have a set of
+      // caller sources mapped to it, use to create the change set
+      Iterator<TokenTupleSet> callerReachabilityItr = callerReachabilityNew.iterator();
+      while( callerReachabilityItr.hasNext() ) {
+       TokenTupleSet ttsRewrittenFinal = callerReachabilityItr.next();
+       HashSet<TokenTupleSet> sourceSets = rewritten2source.get( ttsRewrittenFinal );
+       assert sourceSets != null;
+
+       Iterator<TokenTupleSet> sourceSetsItr = sourceSets.iterator();
+       while( sourceSetsItr.hasNext() ) {
+         TokenTupleSet ttsSource = sourceSetsItr.next();      
+
+         callerChangeSet =
+           callerChangeSet.union( new ChangeTuple( ttsSource, ttsRewrittenFinal ) );
        }
       }
 
-      TokenTuple tokenStarToRewriteJ = paramIndex2paramTokenStar.get(paramIndexJ);
-      assert tokenStarToRewriteJ != null;
-      if( ttsIn.containsTuple(tokenStarToRewriteJ) ) {
-       ReachabilitySet r = ttsIn.rewriteToken(tokenStarToRewriteJ,
-                                              D_j,
-                                              false,
-                                              null);
-       Iterator<TokenTupleSet> ttsItr = r.iterator();
-       while( ttsItr.hasNext() ) {
-         TokenTupleSet tts = ttsItr.next();
-         rsOut = rsOut.union(rewriteDpass(numParameters,
-                                          paramIndex,
-                                          tts,
-                                          paramIndex2rewriteD,
-                                          paramIndex2paramToken,
-                                          paramIndex2paramTokenStar) );
-         rewritten = true;
-       }
-      }
+      assert edgePlannedChanges != null;
+      edgePlannedChanges.put(edge, callerChangeSet);
     }
 
-    if( !rewritten ) {
-      rsOut = rsOut.union(ttsIn);
+    if( hrn == null ) {
+      edge.setBetaNew(edge.getBetaNew().union(callerReachabilityNew) );
+    } else {
+      hrn.setAlphaNew(hrn.getAlphaNew().union(callerReachabilityNew) );
     }
-
-    return rsOut;
   }
 
 
+
   private HashSet<HeapRegionNode>
   getHRNSetThatPossiblyMapToCalleeHRN(OwnershipGraph ogCallee,
                                       HeapRegionNode hrnCallee,
@@ -2202,105 +2216,281 @@ public class OwnershipGraph {
   }
 
 
-  /*
-     // given a set B of heap region node ID's, return the set of heap
-     // region node ID's that is reachable from B
-     public HashSet<Integer> getReachableSet( HashSet<Integer> idSetB ) {
+  public boolean hasPotentialAlias(Integer paramIndex1, Integer paramIndex2) {
 
-      HashSet<HeapRegionNode> toVisit = new HashSet<HeapRegionNode>();
-      HashSet<HeapRegionNode> visited = new HashSet<HeapRegionNode>();
+    // get parameter's heap region
+    assert paramIndex2id.containsKey(paramIndex1);
+    Integer idParam1 = paramIndex2id.get(paramIndex1);
 
-      // initial nodes to visit are from set B
-      Iterator initialItr = idSetB.iterator();
-      while( initialItr.hasNext() ) {
-          Integer idInitial = (Integer) initialItr.next();
-          assert id2hrn.contains( idInitial );
-          HeapRegionNode hrnInitial = id2hrn.get( idInitial );
-          toVisit.add( hrnInitial );
-      }
+    assert id2hrn.containsKey(idParam1);
+    HeapRegionNode hrnParam1 = id2hrn.get(idParam1);
+    assert hrnParam1 != null;
+
+    // get tokens for this parameter
+    TokenTuple p1 = new TokenTuple(hrnParam1.getID(),
+                                   true,
+                                   TokenTuple.ARITY_ONE).makeCanonical();
+
+    TokenTuple pStar1 = new TokenTuple(hrnParam1.getID(),
+                                       true,
+                                       TokenTuple.ARITY_MANY).makeCanonical();
 
-      HashSet<Integer> idSetReachableFromB = new HashSet<Integer>();
 
-      // do a heap traversal
-      while( !toVisit.isEmpty() ) {
-          HeapRegionNode hrnVisited = (HeapRegionNode) toVisit.iterator().next();
-          toVisit.remove( hrnVisited );
-          visited.add   ( hrnVisited );
+    // get tokens for the other parameter
+    assert paramIndex2id.containsKey(paramIndex2);
+    Integer idParam2 = paramIndex2id.get(paramIndex2);
 
-          // for every node visited, add it to the total
-          // reachable set
-          idSetReachableFromB.add( hrnVisited.getID() );
+    assert id2hrn.containsKey(idParam2);
+    HeapRegionNode hrnParam2 = id2hrn.get(idParam2);
+    assert hrnParam2 != null;
 
-          // find other reachable nodes
-          Iterator referenceeItr = hrnVisited.setIteratorToReferencedRegions();
-          while( referenceeItr.hasNext() ) {
-              Map.Entry me                 = (Map.Entry)               referenceeItr.next();
-              HeapRegionNode hrnReferencee = (HeapRegionNode)          me.getKey();
-              ReferenceEdgeProperties rep  = (ReferenceEdgeProperties) me.getValue();
+    TokenTuple p2 = new TokenTuple(hrnParam2.getID(),
+                                   true,
+                                   TokenTuple.ARITY_ONE).makeCanonical();
 
-              if( !visited.contains( hrnReferencee ) ) {
-                  toVisit.add( hrnReferencee );
-              }
-          }
+    TokenTuple pStar2 = new TokenTuple(hrnParam2.getID(),
+                                       true,
+                                       TokenTuple.ARITY_MANY).makeCanonical();
+
+
+    // get special label p_q for first parameter
+    TempDescriptor tdParamQ1 = paramIndex2tdQ.get(paramIndex1);
+    assert tdParamQ1 != null;
+    LabelNode lnParamQ1 = td2ln.get(tdParamQ1);
+    assert lnParamQ1 != null;
+
+    // then get the edge from label q to parameter's hrn
+    ReferenceEdge edgeSpecialQ1 = lnParamQ1.getReferenceTo(hrnParam1, null);
+    assert edgeSpecialQ1 != null;
+
+    // if the beta of this edge has tokens from both parameters in one
+    // token tuple set, then there is a potential alias between them
+    ReachabilitySet beta1 = edgeSpecialQ1.getBeta();
+    assert beta1 != null;
+
+    if( beta1.containsTupleSetWithBoth(p1,     p2) ) {
+      return true;
+    }
+    if( beta1.containsTupleSetWithBoth(pStar1, p2) ) {
+      return true;
+    }
+    if( beta1.containsTupleSetWithBoth(p1,     pStar2) ) {
+      return true;
+    }
+    if( beta1.containsTupleSetWithBoth(pStar1, pStar2) ) {
+      return true;
+    }
+
+    return false;
+  }
+
+
+  public boolean hasPotentialAlias(Integer paramIndex, AllocationSite as) {
+
+    // get parameter's heap region
+    assert paramIndex2id.containsKey(paramIndex);
+    Integer idParam = paramIndex2id.get(paramIndex);
+
+    assert id2hrn.containsKey(idParam);
+    HeapRegionNode hrnParam = id2hrn.get(idParam);
+    assert hrnParam != null;
+
+    // get tokens for this parameter
+    TokenTuple p = new TokenTuple(hrnParam.getID(),
+                                  true,
+                                  TokenTuple.ARITY_ONE).makeCanonical();
+
+    TokenTuple pStar = new TokenTuple(hrnParam.getID(),
+                                      true,
+                                      TokenTuple.ARITY_MANY).makeCanonical();
+
+    // get special label p_q
+    TempDescriptor tdParamQ = paramIndex2tdQ.get(paramIndex);
+    assert tdParamQ != null;
+    LabelNode lnParamQ = td2ln.get(tdParamQ);
+    assert lnParamQ != null;
+
+    // then get the edge from label q to parameter's hrn
+    ReferenceEdge edgeSpecialQ = lnParamQ.getReferenceTo(hrnParam, null);
+    assert edgeSpecialQ != null;
+
+    // look through this beta set for potential aliases
+    ReachabilitySet beta = edgeSpecialQ.getBeta();
+    assert beta != null;
+
+
+    // get tokens for summary node
+    TokenTuple gs = new TokenTuple(as.getSummary(),
+                                   true,
+                                   TokenTuple.ARITY_ONE).makeCanonical();
+
+    TokenTuple gsStar = new TokenTuple(as.getSummary(),
+                                       true,
+                                       TokenTuple.ARITY_MANY).makeCanonical();
+
+    if( beta.containsTupleSetWithBoth(p,     gs) ) {
+      return true;
+    }
+    if( beta.containsTupleSetWithBoth(pStar, gs) ) {
+      return true;
+    }
+    if( beta.containsTupleSetWithBoth(p,     gsStar) ) {
+      return true;
+    }
+    if( beta.containsTupleSetWithBoth(pStar, gsStar) ) {
+      return true;
+    }
+
+    // check for other nodes
+    for( int i = 0; i < as.getAllocationDepth(); ++i ) {
+
+      // the other nodes of an allocation site are single, no stars
+      TokenTuple gi = new TokenTuple(as.getIthOldest(i),
+                                     false,
+                                     TokenTuple.ARITY_ONE).makeCanonical();
+
+      if( beta.containsTupleSetWithBoth(p,     gi) ) {
+       return true;
+      }
+      if( beta.containsTupleSetWithBoth(pStar, gi) ) {
+       return true;
       }
+    }
 
-      return idSetReachableFromB;
-     }
+    return false;
+  }
 
 
-     // used to find if a heap region can possibly have a reference to
-     // any of the heap regions in the given set
-     // if the id supplied is in the set, then a self-referencing edge
-     // would return true, but that special case is specifically allowed
-     // meaning that it isn't an external alias
-     public boolean canIdReachSet( Integer id, HashSet<Integer> idSet ) {
+  public boolean hasPotentialAlias(AllocationSite as1, AllocationSite as2) {
 
-      assert id2hrn.contains( id );
-      HeapRegionNode hrn = id2hrn.get( id );
+    // get tokens for summary nodes
+    TokenTuple gs1 = new TokenTuple(as1.getSummary(),
+                                    true,
+                                    TokenTuple.ARITY_ONE).makeCanonical();
 
+    TokenTuple gsStar1 = new TokenTuple(as1.getSummary(),
+                                        true,
+                                        TokenTuple.ARITY_MANY).makeCanonical();
 
-      //HashSet<HeapRegionNode> hrnSet = new HashSet<HeapRegionNode>();
+    // get summary node's alpha
+    Integer idSum1 = as1.getSummary();
+    assert id2hrn.containsKey(idSum1);
+    HeapRegionNode hrnSum1 = id2hrn.get(idSum1);
+    assert hrnSum1 != null;
+    ReachabilitySet alphaSum1 = hrnSum1.getAlpha();
+    assert alphaSum1 != null;
 
-      //Iterator i = idSet.iterator();
-      //while( i.hasNext() ) {
-      //    Integer idFromSet = (Integer) i.next();
-      //   assert id2hrn.contains( idFromSet );
-      //    hrnSet.add( id2hrn.get( idFromSet ) );
-      //}
 
+    // and for the other one
+    TokenTuple gs2 = new TokenTuple(as2.getSummary(),
+                                    true,
+                                    TokenTuple.ARITY_ONE).makeCanonical();
 
-      // do a traversal from hrn and see if any of the
-      // heap regions from the set come up during that
-      HashSet<HeapRegionNode> toVisit = new HashSet<HeapRegionNode>();
-      HashSet<HeapRegionNode> visited = new HashSet<HeapRegionNode>();
+    TokenTuple gsStar2 = new TokenTuple(as2.getSummary(),
+                                        true,
+                                        TokenTuple.ARITY_MANY).makeCanonical();
 
-      toVisit.add( hrn );
-      while( !toVisit.isEmpty() ) {
-          HeapRegionNode hrnVisited = (HeapRegionNode) toVisit.iterator().next();
-          toVisit.remove( hrnVisited );
-          visited.add   ( hrnVisited );
+    // get summary node's alpha
+    Integer idSum2 = as2.getSummary();
+    assert id2hrn.containsKey(idSum2);
+    HeapRegionNode hrnSum2 = id2hrn.get(idSum2);
+    assert hrnSum2 != null;
+    ReachabilitySet alphaSum2 = hrnSum2.getAlpha();
+    assert alphaSum2 != null;
 
-          Iterator referenceeItr = hrnVisited.setIteratorToReferencedRegions();
-          while( referenceeItr.hasNext() ) {
-              Map.Entry me                 = (Map.Entry)               referenceeItr.next();
-              HeapRegionNode hrnReferencee = (HeapRegionNode)          me.getKey();
-              ReferenceEdgeProperties rep  = (ReferenceEdgeProperties) me.getValue();
+    // does either one report reachability from the other tokens?
+    if( alphaSum1.containsTuple(gsStar2) ) {
+      return true;
+    }
+    if( alphaSum2.containsTuple(gsStar1) ) {
+      return true;
+    }
 
-              if( idSet.contains( hrnReferencee.getID() ) ) {
-                  if( !id.equals( hrnReferencee.getID() ) ) {
-                      return true;
-                  }
-              }
+    // only check non-star token if they are different sites
+    if( as1 != as2 ) {
+      if( alphaSum1.containsTuple(gs2) ) {
+       return true;
+      }
+      if( alphaSum2.containsTuple(gs1) ) {
+       return true;
+      }
+    }
+
+
+    // check sum2 against alloc1 nodes
+    for( int i = 0; i < as1.getAllocationDepth(); ++i ) {
+      Integer idI1 = as1.getIthOldest(i);
+      assert id2hrn.containsKey(idI1);
+      HeapRegionNode hrnI1 = id2hrn.get(idI1);
+      assert hrnI1 != null;
+      ReachabilitySet alphaI1 = hrnI1.getAlpha();
+      assert alphaI1 != null;
+
+      // the other nodes of an allocation site are single, no stars
+      TokenTuple gi1 = new TokenTuple(as1.getIthOldest(i),
+                                      false,
+                                      TokenTuple.ARITY_ONE).makeCanonical();
 
-              if( !visited.contains( hrnReferencee ) ) {
-                  toVisit.add( hrnReferencee );
-              }
-          }
+      if( alphaSum2.containsTuple(gi1) ) {
+       return true;
       }
+      if( alphaI1.containsTuple(gs2) ) {
+       return true;
+      }
+      if( alphaI1.containsTuple(gsStar2) ) {
+       return true;
+      }
+    }
 
-      return false;
-     }
-   */
+    // check sum1 against alloc2 nodes
+    for( int i = 0; i < as2.getAllocationDepth(); ++i ) {
+      Integer idI2 = as2.getIthOldest(i);
+      assert id2hrn.containsKey(idI2);
+      HeapRegionNode hrnI2 = id2hrn.get(idI2);
+      assert hrnI2 != null;
+      ReachabilitySet alphaI2 = hrnI2.getAlpha();
+      assert alphaI2 != null;
+
+      TokenTuple gi2 = new TokenTuple(as2.getIthOldest(i),
+                                      false,
+                                      TokenTuple.ARITY_ONE).makeCanonical();
+
+      if( alphaSum1.containsTuple(gi2) ) {
+       return true;
+      }
+      if( alphaI2.containsTuple(gs1) ) {
+       return true;
+      }
+      if( alphaI2.containsTuple(gsStar1) ) {
+       return true;
+      }
+
+      // while we're at it, do an inner loop for alloc2 vs alloc1 nodes
+      for( int j = 0; j < as1.getAllocationDepth(); ++j ) {
+       Integer idI1 = as1.getIthOldest(j);
+
+       // if these are the same site, don't look for the same token, no alias
+       // different tokens of the same site could alias together though
+       if( idI1 == idI2 ) {
+         continue;
+       }
+
+       HeapRegionNode hrnI1 = id2hrn.get(idI1);
+       ReachabilitySet alphaI1 = hrnI1.getAlpha();
+       TokenTuple gi1 = new TokenTuple(as1.getIthOldest(j),
+                                       false,
+                                       TokenTuple.ARITY_ONE).makeCanonical();
+       if( alphaI2.containsTuple(gi1) ) {
+         return true;
+       }
+       if( alphaI1.containsTuple(gi2) ) {
+         return true;
+       }
+      }
+    }
+
+    return false;
+  }
 
 
   // for writing ownership graphs to dot files
@@ -2309,7 +2499,8 @@ public class OwnershipGraph {
                          boolean writeLabels,
                          boolean labelSelect,
                          boolean pruneGarbage,
-                         boolean writeReferencers
+                         boolean writeReferencers,
+                        boolean writeParamMappings
                          ) throws java.io.IOException {
     writeGraph(
       methodDesc.getSymbol() +
@@ -2318,55 +2509,43 @@ public class OwnershipGraph {
       writeLabels,
       labelSelect,
       pruneGarbage,
-      writeReferencers
+      writeReferencers,
+      writeParamMappings
       );
   }
 
-  /*
-     public void writeGraph(Descriptor methodDesc,
-                         FlatNode fn,
+  public void writeGraph(Descriptor methodDesc,
                          boolean writeLabels,
-                         boolean writeReferencers
+                         boolean labelSelect,
+                         boolean pruneGarbage,
+                         boolean writeReferencers,
+                        boolean writeParamMappings
                          ) throws java.io.IOException {
-     writeGraph(
-      methodDesc.getSymbol() +
-      methodDesc.getNum() +
-      fn.toString(),
-      writeLabels,
-      false,
-      false,
-      writeReferencers
-      );
-     }
 
-     public void writeGraph(Descriptor methodDesc,
-                         boolean writeLabels,
-                         boolean writeReferencers
-                         ) throws java.io.IOException {
-     writeGraph(
-      methodDesc.getSymbol() +
-      methodDesc.getNum() +
-      "COMPLETE",
-      writeLabels,
-      false,
-      false,
-      writeReferencers
-      );
-     }
-   */
+    writeGraph(methodDesc+"COMPLETE",
+               writeLabels,
+               labelSelect,
+               pruneGarbage,
+               writeReferencers,
+              writeParamMappings
+               );
+  }
 
   public void writeGraph(Descriptor methodDesc,
+                         Integer numUpdate,
                          boolean writeLabels,
                          boolean labelSelect,
                          boolean pruneGarbage,
-                         boolean writeReferencers
+                         boolean writeReferencers,
+                        boolean writeParamMappings
                          ) throws java.io.IOException {
 
-    writeGraph(methodDesc+"COMPLETE",
+    writeGraph(methodDesc+"COMPLETE"+String.format("%05d", numUpdate),
                writeLabels,
                labelSelect,
                pruneGarbage,
-               writeReferencers
+               writeReferencers,
+              writeParamMappings
                );
   }
 
@@ -2374,7 +2553,8 @@ public class OwnershipGraph {
                          boolean writeLabels,
                          boolean labelSelect,
                          boolean pruneGarbage,
-                         boolean writeReferencers
+                         boolean writeReferencers,
+                        boolean writeParamMappings
                          ) throws java.io.IOException {
 
     // remove all non-word characters from the graph name so
@@ -2383,7 +2563,6 @@ public class OwnershipGraph {
 
     BufferedWriter bw = new BufferedWriter(new FileWriter(graphName+".dot") );
     bw.write("digraph "+graphName+" {\n");
-    //bw.write( "  size=\"7.5,10\";\n" );
 
     HashSet<HeapRegionNode> visited = new HashSet<HeapRegionNode>();
 
@@ -2407,6 +2586,16 @@ public class OwnershipGraph {
 
     bw.write("  graphTitle[label=\""+graphName+"\",shape=box];\n");
 
+    if( writeParamMappings ) {
+      Set df = paramIndex2id.entrySet();
+      Iterator ih = df.iterator();
+      while( ih.hasNext() ) {
+       Map.Entry meh = (Map.Entry)ih.next();
+       Integer pi = (Integer) meh.getKey();
+       Integer id = (Integer) meh.getValue();
+       bw.write("  pindex"+pi+"[label=\""+pi+" to "+id+"\",shape=box];\n");
+      }
+    }
 
     // then visit every label node, useful for debugging
     if( writeLabels ) {
@@ -2426,7 +2615,7 @@ public class OwnershipGraph {
          }
        }
 
-       bw.write(ln.toString() + ";\n");
+       //bw.write("  "+ln.toString() + ";\n");
 
        Iterator<ReferenceEdge> heapRegionsItr = ln.iteratorToReferencees();
        while( heapRegionsItr.hasNext() ) {