--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/snippets/SnippetCounter.java	Thu Jul 05 10:31:30 2012 +0200
@@ -0,0 +1,149 @@
+/*
+ * 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.graal.hotspot.snippets;
+
+import java.io.*;
+import java.util.*;
+
+import sun.misc.*;
+
+import com.oracle.graal.graph.*;
+import com.oracle.graal.snippets.Snippet.Fold;
+
+/**
+ * A counter that can be safely {@linkplain #inc() incremented} from within a
+ * snippet for gathering snippet specific metrics.
+ */
+public class SnippetCounter implements Comparable<SnippetCounter> {
+
+    /**
+     * A group of related counters.
+     */
+    public static class Group {
+        final String name;
+        final List<SnippetCounter> counters;
+
+        public Group(String name) {
+            this.name = name;
+            this.counters = new ArrayList<>();
+        }
+
+        @Override
+        public synchronized String toString() {
+            Collections.sort(counters);
+
+            long total = 0;
+            for (SnippetCounter c : counters) {
+                total += c.value;
+            }
+
+            StringBuilder buf = new StringBuilder(String.format("Counters: %s%n", name));
+
+            for (SnippetCounter c : counters) {
+                double percent = total == 0D ? 0D : ((double) (c.value * 100)) / total;
+                buf.append(String.format("%16s: %5.2f%%%10d  // %s%n", c.name, percent, c.value, c.description));
+            }
+            return buf.toString();
+        }
+    }
+
+    /**
+     * Sorts counters in descending order of their {@linkplain #value() values}.
+     */
+    @Override
+    public int compareTo(SnippetCounter o) {
+        if (value > o.value) {
+            return -1;
+        } else if (o.value < value) {
+            return 1;
+        }
+        return 0;
+    }
+
+    private static final List<Group> groups = new ArrayList<>();
+
+    private final Group group;
+    private final int index;
+    private final String name;
+    private final String description;
+    private long value;
+
+    @Fold
+    private static int countOffset() {
+        try {
+            return (int) Unsafe.getUnsafe().objectFieldOffset(SnippetCounter.class.getDeclaredField("value"));
+        } catch (Exception e) {
+            throw new GraalInternalError(e);
+        }
+    }
+
+    /**
+     * Creates a counter.
+     *
+     * @param group the group to which the counter belongs. If this is null, the newly created counter is disabled and
+     *            {@linkplain #inc() incrementing} is a no-op.
+     * @param name the name of the counter
+     * @param description a brief comment describing the metric represented by the counter
+     */
+    public SnippetCounter(Group group, String name, String description) {
+        this.group = group;
+        this.name = name;
+        this.description = description;
+        if (group != null) {
+            List<SnippetCounter> counters = group.counters;
+            this.index = counters.size();
+            counters.add(this);
+            if (index == 0) {
+                groups.add(group);
+            }
+        } else {
+            this.index = -1;
+        }
+    }
+
+    /**
+     * Increments the value of this counter. This method can be safely used in a snippet
+     * if it is invoked on a compile-time constant {@link SnippetCounter} object.
+     */
+    public void inc() {
+        if (group != null) {
+            DirectObjectStoreNode.storeLong(this, countOffset(), 0, value + 1);
+        }
+    }
+
+    /**
+     * Gets the value of this counter.
+     */
+    public long value() {
+        return value;
+    }
+
+    /**
+     * Prints all the counter groups to a given stream.
+     */
+    public static void printGroups(PrintStream out) {
+        for (Group group : groups) {
+            out.println(group);
+        }
+    }
+}