--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/TruffleOptions.java	Wed Jun 26 17:21:59 2013 +0200
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api;
+
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.nodes.NodeInfo.Kind;
+
+/**
+ * Class containing general Truffle options.
+ */
+public class TruffleOptions {
+
+    /** Enables/disables the rewriting of traces in the truffle runtime to stdout. */
+    public static final boolean TraceRewrites = true;
+
+    /**
+     * Filters rewrites that do not contain the given string in the qualified name of the source or
+     * target class hierarchy.
+     */
+    public static final String TraceRewritesFilterClass = null;
+
+    /**
+     * Filters rewrites which does not contain the {@link Kind} in its source {@link NodeInfo}. If
+     * no {@link NodeInfo} is defined the element is filtered if the filter value is set.
+     */
+    public static final NodeInfo.Kind TraceRewritesFilterFromKind = null;
+
+    /**
+     * Filters rewrites which does not contain the {@link Kind} in its target {@link NodeInfo}. If
+     * no {@link NodeInfo} is defined the element is filtered if the filter value is set.
+     */
+    public static final NodeInfo.Kind TraceRewritesFilterToKind = null;
+
+}

--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/Node.java	Wed Jun 26 15:22:21 2013 +0200
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/Node.java	Wed Jun 26 17:21:59 2013 +0200
@@ -26,6 +26,7 @@
 import java.util.*;
 
 import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.nodes.NodeInfo.Kind;
 
 /**
  * Abstract base class for all Truffle nodes.
@@ -199,6 +200,72 @@
      * @param reason the reason the replace supplied
      */
     protected void onReplace(Node newNode, String reason) {
+        if (TruffleOptions.TraceRewrites) {
+            Class<? extends Node> from = getClass();
+            Class<? extends Node> to = newNode.getClass();
+
+            if (TruffleOptions.TraceRewritesFilterFromKind != null) {
+                if (filterByKind(from, TruffleOptions.TraceRewritesFilterFromKind)) {
+                    return;
+                }
+            }
+
+            if (TruffleOptions.TraceRewritesFilterToKind != null) {
+                if (filterByKind(to, TruffleOptions.TraceRewritesFilterToKind)) {
+                    return;
+                }
+            }
+
+            String filter = TruffleOptions.TraceRewritesFilterClass;
+            if (filter != null && (filterByContainsClassName(from, filter) || filterByContainsClassName(to, filter))) {
+                return;
+            }
+
+            // CheckStyle: stop system..print check
+            System.out.printf("[truffle]   rewrite %-50s |From %-40s |To %-40s |Reason %s.%n", this.toString(), formatNodeInfo(from), formatNodeInfo(to), reason);
+            // CheckStyle: resume system..print check
+        }
+    }
+
+    private static String formatNodeInfo(Class<? extends Node> clazz) {
+        NodeInfo nodeInfo = clazz.getAnnotation(NodeInfo.class);
+        String kind = "?";
+        if (nodeInfo != null) {
+            switch (nodeInfo.kind()) {
+                case GENERIC:
+                    kind = "G";
+                    break;
+                case SPECIALIZED:
+                    kind = "S";
+                    break;
+                case UNINITIALIZED:
+                    kind = "U";
+                    break;
+                default:
+                    kind = "?";
+                    break;
+            }
+        }
+        return kind + " " + clazz.getSimpleName();
+    }
+
+    private static boolean filterByKind(Class<?> clazz, Kind kind) {
+        NodeInfo info = clazz.getAnnotation(NodeInfo.class);
+        if (info != null) {
+            return info.kind() != kind;
+        }
+        return true;
+    }
+
+    private static boolean filterByContainsClassName(Class<? extends Node> from, String filter) {
+        Class<?> currentFrom = from;
+        while (currentFrom != null) {
+            if (currentFrom.getName().contains(filter)) {
+                return false;
+            }
+            currentFrom = currentFrom.getSuperclass();
+        }
+        return true;
     }
 
     /**