From 15ecf67703750e5e5bf46953f4fa53306cec4731 Mon Sep 17 00:00:00 2001
From: jjenista <jjenista>
Date: Mon, 6 Oct 2008 23:54:38 +0000
Subject: [PATCH] Added hooks for global sweep and made sure that strong update
 logic without effecting the actual strong update does not affect the final
 result.  Next step is to do the strong update edge removal and implement
 global sweep after strong updates and all method calls.

---
 .../OwnershipAnalysis/OwnershipGraph.java     | 80 +++++++++++--------
 1 file changed, 48 insertions(+), 32 deletions(-)

diff --git a/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java b/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java
index a4fa3272..cd46e708 100644
--- a/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java
+++ b/Robust/src/Analysis/OwnershipAnalysis/OwnershipGraph.java
@@ -462,46 +462,45 @@ public class OwnershipGraph {
 	  sourceBetaForNewEdge = edgeY.getBeta();
 	}
 
-	// create the actual reference edge hrnX.f -> hrnY
+	// prepare the new reference edge hrnX.f -> hrnY
 	ReferenceEdge edgeNew = new ReferenceEdge(hrnX,
 	                                          hrnY,
 	                                          f,
 	                                          false,
 	                                          sourceBetaForNewEdge.pruneBy(hrnX.getAlpha() )
 	                                          );
-	addReferenceEdge(hrnX, hrnY, edgeNew);
-
-	/*
-	   if( f != null ) {
-	    // we can do a strong update here if one of two cases holds
-	    // SAVE FOR LATER, WITHOUT STILL CORRECT
-	    if( (hrnX.getNumReferencers() == 1)                           ||
-	        ( lnX.getNumReferencees() == 1 && hrnX.isSingleObject() )
-	      ) {
-	        clearReferenceEdgesFrom( hrnX, f, false );
-	    }
-
-	    addReferenceEdge( hrnX, hrnY, edgeNew );
 
-	   } else {
-	    // if the field is null, or "any" field, then
-	    // look to see if an any field already exists
-	    // and merge with it, otherwise just add the edge
-	    ReferenceEdge edgeExisting = hrnX.getReferenceTo( hrnY, f );
+	// we can do a strong update here if one of two cases holds	
+	boolean strongUpdate = false;
+	if( f != null &&
+	    (   (hrnX.getNumReferencers() == 1)                           ||
+		( lnX.getNumReferencees() == 1 && hrnX.isSingleObject() )
+	    )
+	  ) {
+	  strongUpdate = true;
+	  //clearReferenceEdgesFrom( hrnX, f, false );
+	}
 
-	    if( edgeExisting != null ) {
-	        edgeExisting.setBetaNew(
-	          edgeExisting.getBetaNew().union( edgeNew.getBeta() )
-	                               );
-	        // a new edge here cannot be reflexive, so existing will
-	        // always be also not reflexive anymore
-	        edgeExisting.setIsInitialParamReflexive( false );
+	// look to see if an edge with same field exists
+	// and merge with it, otherwise just add the edge
+	ReferenceEdge edgeExisting = hrnX.getReferenceTo( hrnY, f );
+	  
+	if( edgeExisting != null ) {
+	  edgeExisting.setBetaNew(
+				  edgeExisting.getBetaNew().union( edgeNew.getBeta() )
+				  );
+	  // a new edge here cannot be reflexive, so existing will
+	  // always be also not reflexive anymore
+	  edgeExisting.setIsInitialParamReflexive( false );
+	} else {
+	  addReferenceEdge( hrnX, hrnY, edgeNew );
+	}
 
-	    } else {
-	        addReferenceEdge( hrnX, hrnY, edgeNew );
-	    }
-	   }
-	 */
+	// if it was a strong update, make sure to improve
+	// reachability with a global sweep
+	if( strongUpdate ) {
+	  globalSweep();
+	}	
       }
     }
 
@@ -1501,6 +1500,10 @@ public class OwnershipGraph {
 	}
       }
     }
+
+    // last thing in the entire method call is to do a global sweep
+    // and try to clean up a little bit
+    globalSweep();
   }
 
 
@@ -1798,6 +1801,20 @@ public class OwnershipGraph {
 
 
 
+  ////////////////////////////////////////////////////
+  //
+  //  This global sweep is an optional step to prune
+  //  reachability sets that are not internally
+  //  consistent with the global graph.  It should be
+  //  invoked after strong updates or method calls.
+  //
+  ////////////////////////////////////////////////////
+  protected void globalSweep() {
+    
+  }  
+
+
+
   ////////////////////////////////////////////////////
   // in merge() and equals() methods the suffix A
   // represents the passed in graph and the suffix
@@ -2239,7 +2256,6 @@ public class OwnershipGraph {
     return id2paramIndex.size() == og.id2paramIndex.size();
   }
 
-
   public boolean hasPotentialAlias(Integer paramIndex1, Integer paramIndex2) {
 
     // get parameter's heap region
-- 
2.34.1