--- a/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/CachedGraph.java	Tue May 19 14:00:11 2015 +0200
+++ b/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/CachedGraph.java	Tue May 19 14:24:47 2015 +0200
@@ -22,6 +22,9 @@
  */
 package com.oracle.graal.graph;
 
+import java.util.*;
+import java.util.function.*;
+
 /**
  * This class is a container of a graph that needs to be readonly and optionally a lazily created
  * mutable copy of the graph.
@@ -39,9 +42,9 @@
         return readonlyCopy;
     }
 
-    public Graph getMutableCopy() {
+    public Graph getMutableCopy(Consumer<Map<Node, Node>> duplicationMapCallback) {
         if (mutableCopy == null) {
-            mutableCopy = readonlyCopy.copy();
+            mutableCopy = readonlyCopy.copy(duplicationMapCallback);
         }
         return mutableCopy;
     }

--- a/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/Graph.java	Tue May 19 14:00:11 2015 +0200
+++ b/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/Graph.java	Tue May 19 14:24:47 2015 +0200
@@ -25,6 +25,7 @@
 import static com.oracle.graal.graph.Edges.Type.*;
 
 import java.util.*;
+import java.util.function.*;
 
 import com.oracle.graal.compiler.common.*;
 import com.oracle.graal.debug.*;
@@ -220,7 +221,16 @@
      * Creates a copy of this graph.
      */
     public Graph copy() {
-        return copy(name);
+        return copy(name, null);
+    }
+
+    /**
+     * Creates a copy of this graph.
+     *
+     * @param duplicationMapCallback consumer of the duplication map created during the copying
+     */
+    public Graph copy(Consumer<Map<Node, Node>> duplicationMapCallback) {
+        return copy(name, duplicationMapCallback);
     }
 
     /**
@@ -229,8 +239,21 @@
      * @param newName the name of the copy, used for debugging purposes (can be null)
      */
     public Graph copy(String newName) {
+        return copy(newName, null);
+    }
+
+    /**
+     * Creates a copy of this graph.
+     *
+     * @param newName the name of the copy, used for debugging purposes (can be null)
+     * @param duplicationMapCallback consumer of the duplication map created during the copying
+     */
+    public Graph copy(String newName, Consumer<Map<Node, Node>> duplicationMapCallback) {
         Graph copy = new Graph(newName);
-        copy.addDuplicates(getNodes(), this, this.getNodeCount(), (Map<Node, Node>) null);
+        Map<Node, Node> duplicates = copy.addDuplicates(getNodes(), this, this.getNodeCount(), (Map<Node, Node>) null);
+        if (duplicationMapCallback != null) {
+            duplicationMapCallback.accept(duplicates);
+        }
         return copy;
     }