diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/modref/ModRef.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/modref/ModRef.java
index c77c62ea5..91301ebfd 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/modref/ModRef.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/modref/ModRef.java
@@ -57,7 +57,7 @@ public class ModRef {
    * @throws IllegalArgumentException  if cg is null
    * 
    */
-  public static Map<CGNode, OrdinalSet<PointerKey>> computeMod(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
+  public Map<CGNode, OrdinalSet<PointerKey>> computeMod(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
     if (cg == null) {
       throw new IllegalArgumentException("cg is null");
     }
@@ -71,7 +71,7 @@ public class ModRef {
    * @throws IllegalArgumentException  if cg is null
    * 
    */
-  public static Map<CGNode, OrdinalSet<PointerKey>> computeRef(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
+  public Map<CGNode, OrdinalSet<PointerKey>> computeRef(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
     if (cg == null) {
       throw new IllegalArgumentException("cg is null");
     }
@@ -84,7 +84,7 @@ public class ModRef {
    * model) may it write, including its callees transitively
    * 
    */
-  public static Map<CGNode, OrdinalSet<PointerKey>> computeMod(CallGraph cg, PointerAnalysis pa) {
+  public Map<CGNode, OrdinalSet<PointerKey>> computeMod(CallGraph cg, PointerAnalysis pa) {
     return computeMod(cg, pa, null);
   }
 
@@ -93,11 +93,11 @@ public class ModRef {
    * model) may it read, including its callees transitively
    * 
    */
-  public static Map<CGNode, OrdinalSet<PointerKey>> computeRef(CallGraph cg, PointerAnalysis pa) {
+  public Map<CGNode, OrdinalSet<PointerKey>> computeRef(CallGraph cg, PointerAnalysis pa) {
     return computeRef(cg, pa, null);
   }
 
-  private static Map<CGNode, OrdinalSet<PointerKey>> transitiveClosure(CallGraph cg, Map<CGNode, Collection<PointerKey>> scan) {
+  private Map<CGNode, OrdinalSet<PointerKey>> transitiveClosure(CallGraph cg, Map<CGNode, Collection<PointerKey>> scan) {
     GenReach<CGNode, PointerKey> gr = new GenReach<CGNode, PointerKey>(GraphInverter.invert(cg), scan);
     BitVectorSolver<CGNode> solver = new BitVectorSolver<CGNode>(gr);
     solver.solve();
@@ -116,7 +116,7 @@ public class ModRef {
    * 
    * @param heapExclude
    */
-  private static Map<CGNode, Collection<PointerKey>> scanForMod(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
+  private Map<CGNode, Collection<PointerKey>> scanForMod(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
     Map<CGNode, Collection<PointerKey>> result = HashMapFactory.make();
     for (Iterator<? extends CGNode> it = cg.iterator(); it.hasNext();) {
       CGNode n = it.next();
@@ -131,7 +131,7 @@ public class ModRef {
    * 
    * @param heapExclude
    */
-  private static Map<CGNode, Collection<PointerKey>> scanForRef(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
+  private Map<CGNode, Collection<PointerKey>> scanForRef(CallGraph cg, PointerAnalysis pa, HeapExclusions heapExclude) {
     Map<CGNode, Collection<PointerKey>> result = HashMapFactory.make();
     for (Iterator<? extends CGNode> it = cg.iterator(); it.hasNext();) {
       CGNode n = it.next();
@@ -146,10 +146,10 @@ public class ModRef {
    * 
    * @param heapExclude
    */
-  private static Collection<PointerKey> scanNodeForMod(final CGNode n, final PointerAnalysis pa, HeapExclusions heapExclude) {
+  private Collection<PointerKey> scanNodeForMod(final CGNode n, final PointerAnalysis pa, HeapExclusions heapExclude) {
     Collection<PointerKey> result = HashSetFactory.make();
     final ExtendedHeapModel h = new DelegatingExtendedHeapModel(pa.getHeapModel());
-    SSAInstruction.Visitor v = new ModVisitor(n, result, h, pa);
+    SSAInstruction.Visitor v = makeModVisitor(n, result, pa, h);
     IR ir = n.getIR();
     if (ir != null) {
       for (Iterator<SSAInstruction> it = ir.iterateNormalInstructions(); it.hasNext();) {
@@ -166,10 +166,10 @@ public class ModRef {
    * For a call graph node, what heap locations (as determined by a heap model)
    * may it read, <bf> NOT </bf> including it's callees transitively
    */
-  private static Collection<PointerKey> scanNodeForRef(final CGNode n, final PointerAnalysis pa, HeapExclusions heapExclude) {
+  private Collection<PointerKey> scanNodeForRef(final CGNode n, final PointerAnalysis pa, HeapExclusions heapExclude) {
     Collection<PointerKey> result = HashSetFactory.make();
     final ExtendedHeapModel h = new DelegatingExtendedHeapModel(pa.getHeapModel());
-    SSAInstruction.Visitor v = new RefVisitor(n, result, pa, h);
+    SSAInstruction.Visitor v = makeRefVisitor(n, result, pa, h);
     IR ir = n.getIR();
     if (ir != null) {
       for (Iterator<SSAInstruction> it = ir.iterateNormalInstructions(); it.hasNext();) {
@@ -182,7 +182,7 @@ public class ModRef {
     return result;
   }
 
-  private static final class RefVisitor extends SSAInstruction.Visitor {
+  protected static class RefVisitor extends SSAInstruction.Visitor {
     private final CGNode n;
 
     private final Collection<PointerKey> result;
@@ -191,7 +191,7 @@ public class ModRef {
 
     private final ExtendedHeapModel h;
 
-    private RefVisitor(CGNode n, Collection<PointerKey> result, PointerAnalysis pa, ExtendedHeapModel h) {
+    protected RefVisitor(CGNode n, Collection<PointerKey> result, PointerAnalysis pa, ExtendedHeapModel h) {
       this.n = n;
       this.result = result;
       this.pa = pa;
@@ -230,7 +230,7 @@ public class ModRef {
     }
   }
 
-  private static final class ModVisitor extends SSAInstruction.Visitor {
+  protected static class ModVisitor extends SSAInstruction.Visitor {
     private final CGNode n;
 
     private final Collection<PointerKey> result;
@@ -239,7 +239,8 @@ public class ModRef {
 
     private final PointerAnalysis pa;
 
-    private ModVisitor(CGNode n, Collection<PointerKey> result, ExtendedHeapModel h, PointerAnalysis pa) {
+
+    protected ModVisitor(CGNode n, Collection<PointerKey> result, ExtendedHeapModel h, PointerAnalysis pa) {
       this.n = n;
       this.result = result;
       this.h = h;
@@ -324,24 +325,32 @@ public class ModRef {
     }
   }
 
-  public static Collection<PointerKey> getMod(CGNode n, ExtendedHeapModel h, PointerAnalysis pa, SSAInstruction s,
+  protected ModVisitor makeModVisitor(CGNode n, Collection<PointerKey> result, PointerAnalysis pa, ExtendedHeapModel h) {
+      return new ModVisitor(n, result, h, pa);
+  }
+
+  public Collection<PointerKey> getMod(CGNode n, ExtendedHeapModel h, PointerAnalysis pa, SSAInstruction s,
       HeapExclusions hexcl) {
     if (s == null) {
           throw new IllegalArgumentException("s is null");
         }
     Collection<PointerKey> result = HashSetFactory.make(2);
-    ModVisitor v = new ModVisitor(n, result, h, pa);
+    ModVisitor v = makeModVisitor(n, result, pa, h);
     s.visit(v);
     return hexcl == null ? result : hexcl.filter(result);
   }
 
-  public static Collection<PointerKey> getRef(CGNode n, ExtendedHeapModel h, PointerAnalysis pa, SSAInstruction s,
+  protected RefVisitor makeRefVisitor(CGNode n, Collection<PointerKey> result, PointerAnalysis pa, ExtendedHeapModel h) {
+    return new RefVisitor(n, result, pa, h);
+  }
+
+  public Collection<PointerKey> getRef(CGNode n, ExtendedHeapModel h, PointerAnalysis pa, SSAInstruction s,
       HeapExclusions hexcl) {
     if (s == null) {
           throw new IllegalArgumentException("s is null");
         }
     Collection<PointerKey> result = HashSetFactory.make(2);
-    RefVisitor v = new RefVisitor(n, result, pa, h);
+    RefVisitor v = makeRefVisitor(n, result, pa, h);
     s.visit(v);
     return hexcl == null ? result : hexcl.filter(result);
   }
diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/HeapReachingDefs.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/HeapReachingDefs.java
index 3bb0f0ad5..ef119d6f2 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/HeapReachingDefs.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/HeapReachingDefs.java
@@ -69,6 +69,12 @@ public class HeapReachingDefs {
 
   private static final boolean VERBOSE = false;
 
+  private final ModRef modRef;
+
+  public HeapReachingDefs(ModRef modRef) {
+    this.modRef = modRef;
+  }
+
   /**
    * For each statement s, return the set of statements that may def the heap
    * value read by s.
@@ -93,7 +99,7 @@ public class HeapReachingDefs {
    * @throws IllegalArgumentException
    *             if statements is null
    */
-  public static Map<Statement, OrdinalSet<Statement>> computeReachingDefs(CGNode node, IR ir, PointerAnalysis pa,
+  public Map<Statement, OrdinalSet<Statement>> computeReachingDefs(CGNode node, IR ir, PointerAnalysis pa,
       Map<CGNode, OrdinalSet<PointerKey>> mod, Collection<Statement> statements, HeapExclusions exclusions, CallGraph cg) {
 
     if (statements == null) {
@@ -132,7 +138,7 @@ public class HeapReachingDefs {
         ssaInstructionIndex2Statement, exclusions, cg);
   }
 
-  private static class RDMap implements Map<Statement, OrdinalSet<Statement>> {
+  private class RDMap implements Map<Statement, OrdinalSet<Statement>> {
     final Map<Statement, OrdinalSet<Statement>> delegate = HashMapFactory.make();
 
     private final HeapExclusions exclusions;
@@ -194,7 +200,7 @@ public class HeapReachingDefs {
       return pointerKeyMod;
     }
 
-    private static MutableIntSet findOrCreateIntSet(Map<PointerKey, MutableIntSet> map, PointerKey key) {
+    private MutableIntSet findOrCreateIntSet(Map<PointerKey, MutableIntSet> map, PointerKey key) {
       MutableIntSet result = map.get(key);
       if (result == null) {
         result = new MutableSparseIntSet();
@@ -277,14 +283,14 @@ public class HeapReachingDefs {
      * For a statement s, compute the set of statements that may def the heap
      * value read by s.
      */
-    private OrdinalSet<Statement> computeResult(Statement s, Map<PointerKey, MutableIntSet> pointerKeyMod,
+    OrdinalSet<Statement> computeResult(Statement s, Map<PointerKey, MutableIntSet> pointerKeyMod,
         BitVectorSolver<IBasicBlock> solver, OrdinalSetMapping<Statement> domain, CGNode node, ExtendedHeapModel h,
         PointerAnalysis pa, Map<CGNode, OrdinalSet<PointerKey>> mod, ExplodedControlFlowGraph cfg,
         Map<Integer, NormalStatement> ssaInstructionIndex2Statement) {
       switch (s.getKind()) {
       case NORMAL:
         NormalStatement n = (NormalStatement) s;
-        Collection<PointerKey> ref = ModRef.getRef(node, h, pa, n.getInstruction(), exclusions);
+        Collection<PointerKey> ref = modRef.getRef(node, h, pa, n.getInstruction(), exclusions);
         if (!ref.isEmpty()) {
           IBasicBlock bb = cfg.getBlockForInstruction(n.getInstructionIndex());
           BitVectorVariable v = (BitVectorVariable) solver.getIn(bb);
@@ -359,7 +365,7 @@ public class HeapReachingDefs {
    * For each statement s, compute the set of statements that may def the heap
    * value read by s.
    */
-  private static Map<Statement, OrdinalSet<Statement>> makeResult(BitVectorSolver<IBasicBlock> solver,
+  private Map<Statement, OrdinalSet<Statement>> makeResult(BitVectorSolver<IBasicBlock> solver,
       OrdinalSetMapping<Statement> domain, CGNode node, ExtendedHeapModel h, PointerAnalysis pa,
       Map<CGNode, OrdinalSet<PointerKey>> mod, ExplodedControlFlowGraph cfg,
       Map<Integer, NormalStatement> ssaInstructionIndex2Statement, HeapExclusions exclusions, CallGraph cg) {
@@ -384,12 +390,12 @@ public class HeapReachingDefs {
     return true;
   }
 
-  private static Collection<PointerKey> getMod(Statement s, CGNode n, ExtendedHeapModel h, PointerAnalysis pa,
+  private Collection<PointerKey> getMod(Statement s, CGNode n, ExtendedHeapModel h, PointerAnalysis pa,
       HeapExclusions exclusions) {
     switch (s.getKind()) {
     case NORMAL:
       NormalStatement ns = (NormalStatement) s;
-      return ModRef.getMod(n, h, pa, ns.getInstruction(), exclusions);
+      return modRef.getMod(n, h, pa, ns.getInstruction(), exclusions);
     case HEAP_PARAM_CALLEE:
     case HEAP_RET_CALLER:
       HeapStatement hs = (HeapStatement) s;
@@ -437,7 +443,7 @@ public class HeapReachingDefs {
   /**
    * Reaching def flow functions
    */
-  private static class RD implements ITransferFunctionProvider<IBasicBlock> {
+  private class RD implements ITransferFunctionProvider<IBasicBlock> {
 
     private final CGNode node;
 
@@ -552,7 +558,7 @@ public class HeapReachingDefs {
             assert (domainIndex != -1);
             return heapReturnCaller.getRelated(domainIndex);
           } else {
-            Collection<PointerKey> gen = ModRef.getMod(node, h, pa, s, exclusions);
+            Collection<PointerKey> gen = modRef.getMod(node, h, pa, s, exclusions);
             if (gen.isEmpty()) {
               return null;
             } else {
@@ -587,7 +593,7 @@ public class HeapReachingDefs {
       if (s == null) {
         return null;
       } else {
-        Collection<PointerKey> mod = ModRef.getMod(node, h, pa, s, exclusions);
+        Collection<PointerKey> mod = modRef.getMod(node, h, pa, s, exclusions);
         if (mod.isEmpty()) {
           return null;
         } else {
diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/PDG.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/PDG.java
index 5a3f1499b..bd069b30d 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/PDG.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/PDG.java
@@ -102,6 +102,8 @@ public class PDG extends SlowSparseNumberedGraph<Statement> {
   
   private final CallGraph cg;
 
+  private final ModRef modRef;
+
   /**
    * @param mod
    *            the set of heap locations which may be written (transitively) by
@@ -114,7 +116,7 @@ public class PDG extends SlowSparseNumberedGraph<Statement> {
    */
   public PDG(final CGNode node, PointerAnalysis pa, Map<CGNode, OrdinalSet<PointerKey>> mod,
       Map<CGNode, OrdinalSet<PointerKey>> ref, DataDependenceOptions dOptions, ControlDependenceOptions cOptions,
-      HeapExclusions exclusions, CallGraph cg) {
+	     HeapExclusions exclusions, CallGraph cg, ModRef modRef) {
 
     super();
     if (node == null) {
@@ -127,6 +129,7 @@ public class PDG extends SlowSparseNumberedGraph<Statement> {
     this.dOptions = dOptions;
     this.mod = mod;
     this.exclusions = exclusions;
+    this.modRef = modRef;
     instructionIndices = computeInstructionIndices(node.getIR());
     createNodes(ref, cOptions);
     createScalarEdges(cOptions);
@@ -511,7 +514,7 @@ public class PDG extends SlowSparseNumberedGraph<Statement> {
     };
     Collection<Statement> relevantStatements = Iterator2Collection.toCollection(new FilterIterator<Statement>(iterator(), f));
 
-    Map<Statement, OrdinalSet<Statement>> heapReachingDefs = dOptions.isIgnoreHeap() ? null : HeapReachingDefs.computeReachingDefs(
+    Map<Statement, OrdinalSet<Statement>> heapReachingDefs = dOptions.isIgnoreHeap() ? null : (new HeapReachingDefs(modRef)).computeReachingDefs(
         node, ir, pa, mod, relevantStatements, new HeapExclusions(SetComplement.complement(new SingletonSet(t))), cg);
 
     for (Statement st : heapReachingDefs.keySet()) {
@@ -930,7 +933,7 @@ public class PDG extends SlowSparseNumberedGraph<Statement> {
     case NORMAL:
       NormalStatement st = (NormalStatement) N;
       if (!(IGNORE_ALLOC_HEAP_DEFS && st.getInstruction() instanceof SSANewInstruction)) {
-        Collection<PointerKey> ref = ModRef.getRef(node, heapModel, pa, st.getInstruction(), exclusions);
+	Collection<PointerKey> ref = modRef.getRef(node, heapModel, pa, st.getInstruction(), exclusions);
         for (PointerKey pk : ref) {
           createHeapDataDependenceEdges(pk);
         }
@@ -950,7 +953,7 @@ public class PDG extends SlowSparseNumberedGraph<Statement> {
     case NORMAL:
       NormalStatement st = (NormalStatement) N;
       if (!(IGNORE_ALLOC_HEAP_DEFS && st.getInstruction() instanceof SSANewInstruction)) {
-        Collection<PointerKey> ref = ModRef.getMod(node, heapModel, pa, st.getInstruction(), exclusions);
+	  Collection<PointerKey> ref = modRef.getMod(node, heapModel, pa, st.getInstruction(), exclusions);
         for (PointerKey pk : ref) {
           createHeapDataDependenceEdges(pk);
         }
diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/SDG.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/SDG.java
index 95d278667..dcf10b5ac 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/SDG.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/SDG.java
@@ -106,20 +106,26 @@ public class SDG extends AbstractNumberedGraph<Statement> implements ISDG {
    */
   private final HeapExclusions heapExclude;
 
+  private final ModRef modRef;
 
   public SDG(final CallGraph cg, PointerAnalysis pa, DataDependenceOptions dOptions, ControlDependenceOptions cOptions) {
-    this(cg, pa, dOptions, cOptions, null);
+    this(cg, pa, new ModRef(), dOptions, cOptions, null);
   }
 
-  public SDG(CallGraph cg, PointerAnalysis pa, DataDependenceOptions dOptions, ControlDependenceOptions cOptions, HeapExclusions heapExclude) throws IllegalArgumentException {
+  public SDG(final CallGraph cg, PointerAnalysis pa, ModRef modRef, DataDependenceOptions dOptions, ControlDependenceOptions cOptions) {
+    this(cg, pa, modRef, dOptions, cOptions, null);
+  }
+
+  public SDG(CallGraph cg, PointerAnalysis pa, ModRef modRef, DataDependenceOptions dOptions, ControlDependenceOptions cOptions, HeapExclusions heapExclude) throws IllegalArgumentException {
     super();
     if (dOptions == null) {
       throw new IllegalArgumentException("dOptions must not be null");
     }
+    this.modRef = modRef;
     this.cg = cg;
     this.pa = pa;
-    this.mod = dOptions.isIgnoreHeap() ? null : ModRef.computeMod(cg, pa, heapExclude);
-    this.ref = dOptions.isIgnoreHeap() ? null : ModRef.computeRef(cg, pa, heapExclude);
+    this.mod = dOptions.isIgnoreHeap() ? null : modRef.computeMod(cg, pa, heapExclude);
+    this.ref = dOptions.isIgnoreHeap() ? null : modRef.computeRef(cg, pa, heapExclude);
     this.dOptions = dOptions;
     this.cOptions = cOptions;
     this.heapExclude = heapExclude;
@@ -618,7 +624,7 @@ public class SDG extends AbstractNumberedGraph<Statement> implements ISDG {
   public PDG getPDG(CGNode node) {
     PDG result = pdgMap.get(node);
     if (result == null) {
-      result = new PDG(node, pa, mod, ref, dOptions, cOptions, heapExclude, cg);
+	result = new PDG(node, pa, mod, ref, dOptions, cOptions, heapExclude, cg, modRef);
       pdgMap.put(node, result);
       for (Iterator<? extends Statement> it = result.iterator(); it.hasNext();) {
         nodeMgr.addNode(it.next());
diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/Slicer.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/Slicer.java
index 06e259d94..0acf5091a 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/Slicer.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/Slicer.java
@@ -25,6 +25,7 @@ import com.ibm.wala.dataflow.IFDS.TabulationResult;
 import com.ibm.wala.dataflow.IFDS.TabulationSolver;
 import com.ibm.wala.ipa.callgraph.CallGraph;
 import com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis;
+import com.ibm.wala.ipa.modref.ModRef;
 import com.ibm.wala.ipa.slicer.Statement.Kind;
 import com.ibm.wala.util.collections.HashSetFactory;
 import com.ibm.wala.util.collections.Iterator2Collection;
@@ -190,7 +191,12 @@ public class Slicer {
    * @param ss
    *          a collection of statements of interest
    */
-  private static Collection<Statement> computeSlice(SDG sdg, Collection<Statement> ss, CallGraph cg, PointerAnalysis pa,
+  protected static Collection<Statement> computeSlice(SDG sdg, Collection<Statement> ss, CallGraph cg, PointerAnalysis pa,
+      DataDependenceOptions dOptions, ControlDependenceOptions cOptions, boolean backward) {
+    return computeSlice(sdg, ss, cg, pa, new ModRef(), dOptions, cOptions, backward);
+  }
+
+  protected static Collection<Statement> computeSlice(SDG sdg, Collection<Statement> ss, CallGraph cg, PointerAnalysis pa, ModRef modRef,
       DataDependenceOptions dOptions, ControlDependenceOptions cOptions, boolean backward) {
 
     if (VERBOSE) {
@@ -198,7 +204,7 @@ public class Slicer {
     }
 
     if (sdg == null) {
-      sdg = new SDG(cg, pa, dOptions, cOptions);
+      sdg = new SDG(cg, pa, modRef, dOptions, cOptions);
     }
 
     Collection<Statement> rootsConsidered = HashSetFactory.make();
diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/thin/ThinSlicer.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/thin/ThinSlicer.java
index be5957f95..a31a21d42 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/thin/ThinSlicer.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/slicer/thin/ThinSlicer.java
@@ -61,7 +61,11 @@ public class ThinSlicer {
   private final Graph<Statement> depGraph;
 
   public ThinSlicer(CallGraph cg, PointerAnalysis pa) {
-    SDG sdg = new SDG(cg, pa, DataDependenceOptions.NO_BASE_NO_HEAP, ControlDependenceOptions.NONE, null);
+    this(cg, pa, new ModRef());
+  }
+
+  public ThinSlicer(CallGraph cg, PointerAnalysis pa, ModRef modRef) {
+    SDG sdg = new SDG(cg, pa, modRef, DataDependenceOptions.NO_BASE_NO_HEAP, ControlDependenceOptions.NONE, null);
 
     Map<Statement, Set<PointerKey>> mod = scanForMod(sdg, pa);
     Map<Statement, Set<PointerKey>> ref = scanForRef(sdg, pa);
@@ -270,7 +274,7 @@ public class ThinSlicer {
       Statement st = it.next();
       switch (st.getKind()) {
       case NORMAL:
-        Set<PointerKey> c = HashSetFactory.make(ModRef.getMod(st.getNode(), h, pa, ((NormalStatement) st).getInstruction(),
+	  Set<PointerKey> c = HashSetFactory.make((new ModRef()).getMod(st.getNode(), h, pa, ((NormalStatement) st).getInstruction(),
             null));
         result.put(st, c);
         break;
@@ -290,7 +294,7 @@ public class ThinSlicer {
       Statement st = it.next();
       switch (st.getKind()) {
       case NORMAL:
-        Set<PointerKey> c = HashSetFactory.make(ModRef.getRef(st.getNode(), h, pa, ((NormalStatement) st).getInstruction(),
+	  Set<PointerKey> c = HashSetFactory.make((new ModRef()).getRef(st.getNode(), h, pa, ((NormalStatement) st).getInstruction(),
             null));
         result.put(st, c);
         break;