--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/gen/LIRGenerator.java	Wed Mar 12 20:32:44 2014 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/gen/LIRGenerator.java	Wed Mar 12 20:40:01 2014 +0100
@@ -341,7 +341,8 @@
     }
 
     public LabelRef getLIRBlock(FixedNode b) {
-        Block result = lir.getControlFlowGraph().blockFor(b);
+        assert lir.getControlFlowGraph() instanceof ControlFlowGraph;
+        Block result = ((ControlFlowGraph) lir.getControlFlowGraph()).blockFor(b);
         int suxIndex = currentBlock.getSuccessors().indexOf(result);
         assert suxIndex != -1 : "Block not in successor list of current block";
 

--- a/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/LIR.java	Wed Mar 12 20:32:44 2014 +0100
+++ b/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/LIR.java	Wed Mar 12 20:40:01 2014 +0100
@@ -35,7 +35,7 @@
  */
 public class LIR {
 
-    private final ControlFlowGraph cfg;
+    private final AbstractControlFlowGraph<?> cfg;
 
     /**
      * The linear-scan ordered list of blocks.
@@ -65,14 +65,14 @@
     /**
      * Creates a new LIR instance for the specified compilation.
      */
-    public LIR(ControlFlowGraph cfg, List<? extends AbstractBlock<?>> linearScanOrder, List<? extends AbstractBlock<?>> codeEmittingOrder) {
+    public LIR(AbstractControlFlowGraph<?> cfg, List<? extends AbstractBlock<?>> linearScanOrder, List<? extends AbstractBlock<?>> codeEmittingOrder) {
         this.cfg = cfg;
         this.codeEmittingOrder = codeEmittingOrder;
         this.linearScanOrder = linearScanOrder;
         this.lirInstructions = new BlockMap<>(cfg);
     }
 
-    public ControlFlowGraph getControlFlowGraph() {
+    public AbstractControlFlowGraph<?> getControlFlowGraph() {
         return cfg;
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/cfg/AbstractControlFlowGraph.java	Wed Mar 12 20:40:01 2014 +0100
@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2014, 2014, 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.graal.nodes.cfg;
+
+public interface AbstractControlFlowGraph<T extends AbstractBlock<T>> {
+
+    T[] getBlocks();
+
+    Loop[] getLoops();
+
+    Block getStartBlock();
+}

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/cfg/BlockMap.java	Wed Mar 12 20:32:44 2014 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/cfg/BlockMap.java	Wed Mar 12 20:40:01 2014 +0100
@@ -27,7 +27,7 @@
     private final T[] data;
 
     @SuppressWarnings("unchecked")
-    public BlockMap(ControlFlowGraph cfg) {
+    public BlockMap(AbstractControlFlowGraph<?> cfg) {
         data = (T[]) new Object[cfg.getBlocks().length];
     }
 

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/cfg/ControlFlowGraph.java	Wed Mar 12 20:32:44 2014 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/cfg/ControlFlowGraph.java	Wed Mar 12 20:40:01 2014 +0100
@@ -28,7 +28,7 @@
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 
-public class ControlFlowGraph {
+public class ControlFlowGraph implements AbstractControlFlowGraph<Block> {
 
     public final StructuredGraph graph;
 

--- a/graal/com.oracle.graal.printer/src/com/oracle/graal/printer/CFGPrinterObserver.java	Wed Mar 12 20:32:44 2014 +0100
+++ b/graal/com.oracle.graal.printer/src/com/oracle/graal/printer/CFGPrinterObserver.java	Wed Mar 12 20:40:01 2014 +0100
@@ -141,7 +141,8 @@
             cfgPrinter.target = cfgPrinter.lirGenerator.target();
         }
         if (cfgPrinter.lir != null) {
-            cfgPrinter.cfg = cfgPrinter.lir.getControlFlowGraph();
+            assert cfgPrinter.lir.getControlFlowGraph() instanceof ControlFlowGraph;
+            cfgPrinter.cfg = (ControlFlowGraph) cfgPrinter.lir.getControlFlowGraph();
         }
 
         CodeCacheProvider codeCache = Debug.contextLookup(CodeCacheProvider.class);