--- a/graal/com.oracle.graal.truffle.hotspot/src/com/oracle/graal/truffle/hotspot/HotSpotFrameInstance.java	Wed Apr 16 18:33:10 2014 +0200
+++ b/graal/com.oracle.graal.truffle.hotspot/src/com/oracle/graal/truffle/hotspot/HotSpotFrameInstance.java	Wed Apr 16 18:51:54 2014 +0200
@@ -154,7 +154,7 @@
         public static final Method METHOD;
         static {
             try {
-                METHOD = RootCallTarget.class.getDeclaredMethod("callProxy", VirtualFrame.class);
+                METHOD = OptimizedCallTarget.class.getDeclaredMethod("callProxy", VirtualFrame.class);
             } catch (NoSuchMethodException | SecurityException e) {
                 throw new GraalInternalError(e);
             }

--- a/graal/com.oracle.graal.truffle/src/com/oracle/graal/truffle/OptimizedCallTarget.java	Wed Apr 16 18:33:10 2014 +0200
+++ b/graal/com.oracle.graal.truffle/src/com/oracle/graal/truffle/OptimizedCallTarget.java	Wed Apr 16 18:51:54 2014 +0200
@@ -38,7 +38,7 @@
 /**
  * Call target that is optimized by Graal upon surpassing a specific invocation threshold.
  */
-public abstract class OptimizedCallTarget extends RootCallTarget implements LoopCountReceiver, ReplaceObserver {
+public abstract class OptimizedCallTarget extends InstalledCode implements RootCallTarget, LoopCountReceiver, ReplaceObserver {
 
     protected static final PrintStream OUT = TTY.out().out();
 
@@ -51,8 +51,16 @@
     private OptimizedCallTarget splitSource;
     private final AtomicInteger callSitesKnown = new AtomicInteger(0);
 
+    private final RootNode rootNode;
+
+    public final RootNode getRootNode() {
+        return rootNode;
+    }
+
     public OptimizedCallTarget(RootNode rootNode, int invokeCounter, int compilationThreshold, boolean compilationEnabled, CompilationPolicy compilationPolicy) {
-        super(rootNode);
+        this.rootNode = rootNode;
+        this.rootNode.adoptChildren();
+        this.rootNode.setCallTarget(this);
         this.installedCode = new InstalledCode();
         this.compilationEnabled = compilationEnabled;
         this.compilationPolicy = compilationPolicy;
@@ -62,6 +70,15 @@
         }
     }
 
+    protected final Object callProxy(VirtualFrame frame) {
+        try {
+            return getRootNode().execute(frame);
+        } finally {
+            // this assertion is needed to keep the values from being cleared as non-live locals
+            assert frame != null && this != null;
+        }
+    }
+
     public final int getKnownCallSiteCount() {
         return callSitesKnown.get();
     }
@@ -84,7 +101,7 @@
 
     @Override
     public String toString() {
-        String superString = super.toString();
+        String superString = rootNode.toString();
         if (installedCode.isValid()) {
             superString += " <compiled>";
         }

--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/RootCallTarget.java	Wed Apr 16 18:33:10 2014 +0200
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/RootCallTarget.java	Wed Apr 16 18:51:54 2014 +0200
@@ -24,38 +24,13 @@
  */
 package com.oracle.truffle.api;
 
-import com.oracle.truffle.api.frame.*;
 import com.oracle.truffle.api.nodes.*;
 
 /**
  * Represents the target of a call to a {@link RootNode}, i.e., to another tree of nodes. Instances
  * of this class can be created using {@link TruffleRuntime#createCallTarget(RootNode)}.
  */
-public abstract class RootCallTarget implements CallTarget {
-
-    private final RootNode rootNode;
-
-    public RootCallTarget(RootNode function) {
-        this.rootNode = function;
-        this.rootNode.adoptChildren();
-        this.rootNode.setCallTarget(this);
-    }
+public interface RootCallTarget extends CallTarget {
 
-    @Override
-    public String toString() {
-        return rootNode.toString();
-    }
-
-    public final RootNode getRootNode() {
-        return rootNode;
-    }
-
-    protected final Object callProxy(VirtualFrame frame) {
-        try {
-            return getRootNode().execute(frame);
-        } finally {
-            // this assertion is needed to keep the values from being cleared as non-live locals
-            assert frame != null && this != null;
-        }
-    }
+    RootNode getRootNode();
 }

--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/impl/DefaultCallTarget.java	Wed Apr 16 18:33:10 2014 +0200
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/impl/DefaultCallTarget.java	Wed Apr 16 18:51:54 2014 +0200
@@ -32,15 +32,28 @@
  * This is an implementation-specific class. Do not use or instantiate it. Instead, use
  * {@link TruffleRuntime#createCallTarget(RootNode)} to create a {@link RootCallTarget}.
  */
-public class DefaultCallTarget extends RootCallTarget {
+public class DefaultCallTarget implements RootCallTarget {
+
+    private final RootNode rootNode;
 
-    protected DefaultCallTarget(RootNode function) {
-        super(function);
+    public DefaultCallTarget(RootNode function) {
+        this.rootNode = function;
+        this.rootNode.adoptChildren();
+        this.rootNode.setCallTarget(this);
+    }
+
+    @Override
+    public String toString() {
+        return rootNode.toString();
+    }
+
+    public final RootNode getRootNode() {
+        return rootNode;
     }
 
     @Override
     public Object call(Object... args) {
         VirtualFrame frame = new DefaultVirtualFrame(getRootNode().getFrameDescriptor(), args);
-        return callProxy(frame);
+        return getRootNode().execute(frame);
     }
 }