--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.jvmci.debug/src/com/oracle/jvmci/debug/DebugMetric.java	Tue May 26 23:21:15 2015 +0200
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 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.jvmci.debug;
+
+/**
+ * A counter for some value of interest.
+ */
+public interface DebugMetric {
+
+    /**
+     * Adds 1 to this counter if metering is {@link Debug#isMeterEnabled() enabled} or this is an
+     * {@linkplain #isConditional() unconditional} metric.
+     */
+    void increment();
+
+    /**
+     * Adds {@code value} to this counter if metering is {@link Debug#isMeterEnabled() enabled} or
+     * this is an {@linkplain #isConditional() unconditional} metric.
+     */
+    void add(long value);
+
+    /**
+     * Sets a flag determining if this counter is only enabled if metering is
+     * {@link Debug#isMeterEnabled() enabled}.
+     */
+    void setConditional(boolean flag);
+
+    /**
+     * Determines if this counter is only enabled if metering is {@link Debug#isMeterEnabled()
+     * enabled}.
+     */
+    boolean isConditional();
+
+    /**
+     * Gets the current value of this metric.
+     */
+    long getCurrentValue();
+
+    /**
+     * Determines if this counter is enabled (either conditionally or unconditionally).
+     */
+    default boolean isEnabled() {
+        return !isConditional() || Debug.isMeterEnabled();
+    }
+}