explicit null heap region changes rolled back

diff --git a/Robust/src/Analysis/OwnershipAnalysis/OwnershipAnalysis.java b/Robust/src/Analysis/OwnershipAnalysis/OwnershipAnalysis.java
index f1d1d1c615088d31420b01118d5e1a9e4f77cc8f..97cc05be0d8a5446581c72b8f3bd0dad257fd5d9 100644 (file)
--- a/Robust/src/Analysis/OwnershipAnalysis/OwnershipAnalysis.java
+++ b/Robust/src/Analysis/OwnershipAnalysis/OwnershipAnalysis.java
@@ -313,11 +313,6 @@ public class OwnershipAnalysis {
   // reserved IDs for special purposes
   static private int uniqueIDcount = 10;
 
-  // special purpose region for "null" 
-  // included in every graph
-  static public int nullRegionID =  9;
-
-
   // Use these data structures to track progress of
   // processing all methods in the program, and by methods
   // TaskDescriptor and MethodDescriptor are combined
@@ -760,17 +755,7 @@ public class OwnershipAnalysis {
        og.merge(ogInitParamAlloc);
       }
       break;
-
-    case FKind.FlatLiteralNode:
-      FlatLiteralNode fln = (FlatLiteralNode) fn;
-      if( fln.getValue() == null ) {
-       // when we set something to null, use the special
-       // "null" heap region as the target
-       lhs = fln.getDst();
-       og.assignTempXEqualToNull(lhs);
-      }
-      break;
-
+      
     case FKind.FlatOpNode:
       FlatOpNode fon = (FlatOpNode) fn;
       if( fon.getOp().getOp() == Operation.ASSIGN ) {

diff --git a/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java b/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java
index 9a0faf11faf2b86a7d76fd71f2124581283a7943..717b612c0b4d3db79673ebdf506c5621bc67838d 100644 (file)
--- a/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java
+++ b/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java
@@ -67,9 +67,6 @@ public class OwnershipGraph {
   public Hashtable<Integer, TokenTuple> paramIndex2paramTokenSecondaryStar;
 
 
-  public HeapRegionNode hrnNull;
-
-
   public OwnershipGraph(int allocationDepth, TypeUtil typeUtil) {
     this.allocationDepth = allocationDepth;
     this.typeUtil        = typeUtil;
@@ -94,16 +91,6 @@ public class OwnershipGraph {
     paramIndex2paramTokenSecondaryStar = new Hashtable<Integer,        TokenTuple    >();
 
     allocationSites = new HashSet <AllocationSite>();
-
-    hrnNull = createNewHeapRegionNode( OwnershipAnalysis.nullRegionID,
-                                      false,
-                                      false,
-                                      false,
-                                      false,
-                                      null,
-                                      null,
-                                      null,
-                                      "null" );
   }
 
 
@@ -321,23 +308,6 @@ public class OwnershipGraph {
   }
 
 
-  public void assignTempXEqualToNull(TempDescriptor x) {
-
-    LabelNode lnX = getLabelNodeFromTemp(x);
-
-    clearReferenceEdgesFrom(lnX, null, null, true);
-
-    ReferenceEdge edgeNew = new ReferenceEdge(lnX,
-                                             hrnNull,
-                                             null,
-                                             null,
-                                             false,
-                                             null);
-
-    addReferenceEdge(lnX, hrnNull, edgeNew);
-  }
-
-
   public void assignTypedTempXEqualToTempY(TempDescriptor x,
                                           TempDescriptor y,
                                           TypeDescriptor type) {
@@ -375,12 +345,6 @@ public class OwnershipGraph {
       HeapRegionNode  hrnY  = edgeY.getDst();
       ReachabilitySet betaY = edgeY.getBeta();
 
-      // skip the null region, load statement is not
-      // meaningful for this region
-      if( hrnY == hrnNull ) {
-       continue;
-      }
-
       Iterator<ReferenceEdge> itrHrnFhrn = hrnY.iteratorToReferencees();
       while( itrHrnFhrn.hasNext() ) {
        ReferenceEdge   edgeHrn = itrHrnFhrn.next();
@@ -423,11 +387,6 @@ public class OwnershipGraph {
       ReferenceEdge edgeX = itrXhrn.next();
       HeapRegionNode hrnX = edgeX.getDst();
 
-      // if we are looking at the null region, skip
-      if( hrnX == hrnNull ) {
-       continue;
-      }
-
       // we can do a strong update here if one of two cases holds      
       if( f != null &&
          f != OwnershipAnalysis.getArrayField( f.getType() ) &&            
@@ -447,11 +406,6 @@ public class OwnershipGraph {
       HeapRegionNode hrnX = edgeX.getDst();
       ReachabilitySet betaX = edgeX.getBeta();
 
-      // if we are looking at the null region, skip
-      if( hrnX == hrnNull ) {
-       continue;
-      }
-
       ReachabilitySet R = hrnX.getAlpha().intersection(edgeX.getBeta() );
 
       Iterator<ReferenceEdge> itrYhrn = lnY.iteratorToReferencees();
@@ -506,11 +460,6 @@ public class OwnershipGraph {
       ReferenceEdge edgeX = itrXhrn.next();
       HeapRegionNode hrnX = edgeX.getDst();
 
-      // if we are looking at the null region, skip
-      if( hrnX == hrnNull ) {
-       continue;
-      }
-
       Iterator<ReferenceEdge> itrYhrn = lnY.iteratorToReferencees();
       while( itrYhrn.hasNext() ) {
        ReferenceEdge edgeY = itrYhrn.next();
@@ -1197,18 +1146,18 @@ public class OwnershipGraph {
     assert x  != null;
     assert as != null;
 
-    age(as);
+    age( as );
 
     // after the age operation the newest (or zero-ith oldest)
     // node associated with the allocation site should have
     // no references to it as if it were a newly allocated
     // heap region
-    Integer idNewest  = as.getIthOldest(0);
-    HeapRegionNode hrnNewest = id2hrn.get(idNewest);
-    assert hrnNewest != null;
+    Integer        idNewest   = as.getIthOldest( 0 );
+    HeapRegionNode hrnNewest  = id2hrn.get( idNewest );
+    assert         hrnNewest != null;
 
-    LabelNode lnX = getLabelNodeFromTemp(x);
-    clearReferenceEdgesFrom(lnX, null, null, true);
+    LabelNode lnX = getLabelNodeFromTemp( x );
+    clearReferenceEdgesFrom( lnX, null, null, true );
 
     // make a new reference to allocated node
     TypeDescriptor type    = as.getType();
@@ -1222,50 +1171,6 @@ public class OwnershipGraph {
                         );
 
     addReferenceEdge( lnX, hrnNewest, edgeNew );
-
-    // if there are class or array fields, initialize 
-    // all of them to the null heap region
-    if( type.isArray() ) {
-      /*
-      TypeDescriptor  tdElement  = type.dereference();
-      FieldDescriptor fdElement  = OwnershipAnalysis.getArrayField( tdElement );
-      ReferenceEdge   edgeToNull =
-       new ReferenceEdge( hrnNewest,             // source
-                          hrnNull,               // dest
-                          fdElement.getType(),   // type
-                          fdElement.getSymbol(), // field name
-                          false,                 // is initial param
-                          null                   // beta
-                          );
-      addReferenceEdge( hrnNewest, hrnNull, edgeToNull );              
-      */
-
-    } else if( type.isClass() ) {
-      ClassDescriptor cd = type.getClassDesc();
-      while( cd != null ) {
-
-       Iterator<FieldDescriptor> fieldItr = cd.getFields();
-       while( fieldItr.hasNext() ) {     
-         FieldDescriptor fd        = fieldItr.next();
-         TypeDescriptor  typeField = fd.getType();
-
-         assert typeField != null;
-
-         ReferenceEdge edgeToNull =
-           new ReferenceEdge( hrnNewest,             // source
-                              hrnNull,               // dest
-                              typeField,             // type
-                              typeField.getSymbol(), // field name
-                              false,                 // is initial param
-                              null                   // beta
-                              );
-
-         addReferenceEdge( hrnNewest, hrnNull, edgeToNull );     
-       }
-
-       cd = cd.getSuperDesc();
-      }
-    }
   }
 
 
@@ -2808,9 +2713,6 @@ public class OwnershipGraph {
                                                 pi2dr,
                                                 pi2r );
 
-         // always remove the null region as a possible source of edges
-         possibleCallerSrcs.remove( hrnNull );
-
          HashSet<HeapRegionNode> possibleCallerDsts =
            getHRNSetThatPossiblyMapToCalleeHRN( ogCallee,
                                                 edgeCallee.getDst(),
@@ -3312,12 +3214,6 @@ public class OwnershipGraph {
     
     HashSet<HeapRegionNode> possibleCallerHRNs = new HashSet<HeapRegionNode>();
 
-    if( hrnCallee == ogCallee.hrnNull ) {
-      // this is the null heap region
-      possibleCallerHRNs.add( id2hrn.get( hrnCallee.getID() ) );
-      return possibleCallerHRNs;
-    }
-
     Set<Integer> paramIndicesCallee_p = ogCallee.idPrimary2paramIndexSet  .get( hrnCallee.getID() );
     Set<Integer> paramIndicesCallee_s = ogCallee.idSecondary2paramIndexSet.get( hrnCallee.getID() );