--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/AcquiredCASLockNode.java	Wed Nov 25 14:50:57 2015 +0100
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2015, 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.hotspot.nodes;
+
+import com.oracle.graal.compiler.common.type.StampFactory;
+import com.oracle.graal.graph.NodeClass;
+import com.oracle.graal.nodeinfo.NodeInfo;
+import com.oracle.graal.nodes.FixedWithNextNode;
+import com.oracle.graal.nodes.ValueNode;
+import com.oracle.graal.nodes.spi.LIRLowerable;
+import com.oracle.graal.nodes.spi.NodeLIRBuilderTool;
+
+/**
+ * Marks the control flow path where an object acquired a lightweight lock based on an atomic
+ * compare-and-swap (CAS) of the mark word in the object's header.
+ */
+@NodeInfo
+public final class AcquiredCASLockNode extends FixedWithNextNode implements LIRLowerable {
+    public static final NodeClass<AcquiredCASLockNode> TYPE = NodeClass.create(AcquiredCASLockNode.class);
+
+    @Input ValueNode object;
+
+    public AcquiredCASLockNode(ValueNode object) {
+        super(TYPE, StampFactory.forVoid());
+        this.object = object;
+    }
+
+    public ValueNode object() {
+        return object;
+    }
+
+    public void generate(NodeLIRBuilderTool generator) {
+        // This is just a marker node so it generates nothing
+    }
+
+    @NodeIntrinsic
+    public static native void mark(Object object);
+}

--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java	Wed Nov 25 14:48:57 2015 +0100
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java	Wed Nov 25 14:50:57 2015 +0100
@@ -74,6 +74,7 @@
 import com.oracle.graal.graph.iterators.NodeIterable;
 import com.oracle.graal.hotspot.meta.HotSpotProviders;
 import com.oracle.graal.hotspot.meta.HotSpotRegistersProvider;
+import com.oracle.graal.hotspot.nodes.AcquiredCASLockNode;
 import com.oracle.graal.hotspot.nodes.CurrentLockNode;
 import com.oracle.graal.hotspot.nodes.DirectCompareAndSwapNode;
 import com.oracle.graal.hotspot.nodes.FastAcquireBiasedLockNode;
@@ -394,6 +395,7 @@
         } else {
             traceObject(trace, "+lock{cas}", object, true);
             lockCas.inc();
+            AcquiredCASLockNode.mark(object);
         }
     }
 
@@ -669,7 +671,7 @@
     private static native void monitorenterStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
 
     @NodeIntrinsic(ForeignCallNode.class)
-    private static native void monitorexitStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
+    public static native void monitorexitStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
 
     /**
      * Counters for the various paths for acquiring a lock. The counters whose names start with