--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/nodes/MonitorCounterNode.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2012, 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 org.graalvm.compiler.hotspot.nodes;
+
+import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;
+
+import java.util.BitSet;
+
+import org.graalvm.compiler.core.common.type.StampFactory;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.NodeClass;
+import org.graalvm.compiler.lir.VirtualStackSlot;
+import org.graalvm.compiler.nodeinfo.NodeCycles;
+import org.graalvm.compiler.nodeinfo.NodeInfo;
+import org.graalvm.compiler.nodes.calc.FloatingNode;
+import org.graalvm.compiler.nodes.spi.LIRLowerable;
+import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
+import org.graalvm.compiler.word.Word;
+import org.graalvm.compiler.word.WordTypes;
+
+import jdk.vm.ci.meta.Value;
+
+/**
+ * Node that is used to maintain a stack based counter of how many locks are currently held.
+ */
+@NodeInfo(cycles = NodeCycles.CYCLES_2, size = SIZE_1)
+public final class MonitorCounterNode extends FloatingNode implements LIRLowerable, Node.ValueNumberable {
+    public static final NodeClass<MonitorCounterNode> TYPE = NodeClass.create(MonitorCounterNode.class);
+
+    public MonitorCounterNode(@InjectedNodeParameter WordTypes wordTypes) {
+        super(TYPE, StampFactory.forKind(wordTypes.getWordKind()));
+    }
+
+    @Override
+    public void generate(NodeLIRBuilderTool gen) {
+        assert graph().getNodes().filter(MonitorCounterNode.class).count() == 1 : "monitor counters not canonicalized to single instance";
+        VirtualStackSlot counter = gen.getLIRGeneratorTool().getResult().getFrameMapBuilder().allocateStackSlots(1, new BitSet(0), null);
+        Value result = gen.getLIRGeneratorTool().emitAddress(counter);
+        gen.setResult(this, result);
+    }
+
+    @NodeIntrinsic
+    public static native Word counter();
+}