--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.tools/src/com/oracle/truffle/tools/CoverageTracker.java	Tue May 26 16:38:13 2015 -0700
@@ -0,0 +1,320 @@
+/*
+ * 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.truffle.tools;
+
+import java.io.*;
+import java.util.*;
+import java.util.Map.Entry;
+
+import com.oracle.truffle.api.instrument.*;
+import com.oracle.truffle.api.instrument.impl.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.source.*;
+
+/**
+ * An {@link InstrumentationTool} that counts interpreter <em>execution calls</em> to AST nodes that
+ * hold a specified {@linkplain SyntaxTag syntax tag}, tabulated by source and line number
+ * associated with each node. Syntax tags are presumed to be applied external to the tool. If no tag
+ * is specified, {@linkplain StandardSyntaxTag#STATEMENT STATEMENT} is used, corresponding to
+ * conventional behavior for code coverage tools.
+ * <p>
+ * No counts will be kept for execution in sources that hold the {@link SourceTag}
+ * {@link Tags#NO_COVERAGE}.
+ * <p>
+ * <b>Tool Life Cycle</b>
+ * <p>
+ * See {@link InstrumentationTool} for the life cycle common to all such tools.
+ * <p>
+ * <b>Execution Counts</b>
+ * <p>
+ * <ul>
+ * <li>"Execution call" on a node is is defined as invocation of a node method that is instrumented
+ * to produce the event {@link SimpleInstrumentListener#enter(Probe)};</li>
+ * <li>Execution calls are tabulated only at <em>instrumented</em> nodes, i.e. those for which
+ * {@linkplain Node#isInstrumentable() isInstrumentable() == true};</li>
+ * <li>Execution calls are tabulated only at nodes present in the AST when originally created;
+ * dynamically added nodes will not be instrumented.</li>
+ * </ul>
+ * </p>
+ * <b>Results</b>
+ * <p>
+ * A modification-safe copy of the {@linkplain #getCounts() counts} can be retrieved at any time,
+ * without effect on the state of the tool.
+ * </p>
+ * <p>
+ * A "default" {@linkplain #print(PrintStream) print()} method can summarizes the current counts at
+ * any time in a simple textual format, with no other effect on the state of the tool.
+ * </p>
+ *
+ * @see Instrument
+ * @see SyntaxTag
+ */
+public final class CoverageTracker extends InstrumentationTool {
+
+    public enum Tags implements SourceTag {
+
+        /**
+         * Report no counts for sources holding this tag.
+         */
+        NO_COVERAGE("No Coverage", "Coverage Tracker will igore");
+
+        private final String name;
+        private final String description;
+
+        private Tags(String name, String description) {
+            this.name = name;
+            this.description = description;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public String getDescription() {
+            return description;
+        }
+    }
+
+    /** Counting data. */
+    private final Map<LineLocation, CoverageRecord> coverageMap = new HashMap<>();
+
+    /** Needed for disposal. */
+    private final List<Instrument> instruments = new ArrayList<>();
+
+    /**
+     * Coverage counting is restricted to nodes holding this tag.
+     */
+    private final SyntaxTag countingTag;
+
+    private final ProbeListener probeListener;
+
+    /**
+     * Create a per-line coverage tool for nodes tagged as {@linkplain StandardSyntaxTag#STATEMENT
+     * statements} in subsequently created ASTs.
+     */
+    public CoverageTracker() {
+        this(StandardSyntaxTag.STATEMENT);
+    }
+
+    /**
+     * Create a per-line coverage tool for nodes tagged as specified, presuming that tags applied
+     * outside this tool.
+     */
+    public CoverageTracker(SyntaxTag tag) {
+        this.probeListener = new CoverageProbeListener();
+        this.countingTag = tag;
+    }
+
+    @Override
+    protected boolean internalInstall() {
+        Probe.addProbeListener(probeListener);
+        return true;
+    }
+
+    @Override
+    protected void internalReset() {
+        coverageMap.clear();
+    }
+
+    @Override
+    protected void internalDispose() {
+        Probe.removeProbeListener(probeListener);
+        for (Instrument instrument : instruments) {
+            instrument.dispose();
+        }
+    }
+
+    /**
+     * Gets a modification-safe summary of the current per-type node execution counts; does not
+     * affect the counts.
+     * <p>
+     * The map holds an array for each source, and elements of the a array corresponding to the
+     * textual lines of that source. An array entry contains null if the corresponding line of
+     * source is associated with no nodes of the relevant type, i.e. where no count was made. A
+     * numeric entry represents the execution count at the corresponding line of source.
+     * <p>
+     * <b>Note:</b> source line numbers are 1-based, so array index {@code i} corresponds to source
+     * line number {@code i + 1}
+     */
+    public Map<Source, Long[]> getCounts() {
+
+        /**
+         * Counters for every {Source, line number} for which a counter was installed, i.e. for
+         * every line associated with an appropriately tagged AST node; iterable in order of source
+         * name, then line number.
+         */
+        final TreeSet<Entry<LineLocation, CoverageRecord>> entries = new TreeSet<>(new LineLocationEntryComparator());
+
+        for (Entry<LineLocation, CoverageRecord> entry : coverageMap.entrySet()) {
+            entries.add(entry);
+        }
+        final Map<Source, Long[]> result = new HashMap<>();
+        Source curSource = null;
+        Long[] curLineTable = null;
+        for (Entry<LineLocation, CoverageRecord> entry : entries) {
+            final LineLocation key = entry.getKey();
+            final Source source = key.getSource();
+            final int lineNo = key.getLineNumber();
+            if (source != curSource) {
+                if (curSource != null) {
+                    result.put(curSource, curLineTable);
+                }
+                curSource = source;
+                curLineTable = new Long[source.getLineCount()];
+            }
+            curLineTable[lineNo - 1] = entry.getValue().count;
+        }
+        if (curSource != null) {
+            result.put(curSource, curLineTable);
+        }
+        return result;
+    }
+
+    /**
+     * A default printer for the current line counts, producing lines of the form " (<count>) <line
+     * number> : <text of line>", grouped by source.
+     */
+    public void print(PrintStream out) {
+        out.println();
+        out.println(countingTag.name() + " coverage:");
+
+        /**
+         * Counters for every {Source, line number} for which a counter was installed, i.e. for
+         * every line associated with an appropriately tagged AST node; iterable in order of source
+         * name, then line number.
+         */
+        final TreeSet<Entry<LineLocation, CoverageRecord>> entries = new TreeSet<>(new LineLocationEntryComparator());
+
+        for (Entry<LineLocation, CoverageRecord> entry : coverageMap.entrySet()) {
+            entries.add(entry);
+        }
+        Source curSource = null;
+        int curLineNo = 1;
+        for (Entry<LineLocation, CoverageRecord> entry : entries) {
+            final LineLocation key = entry.getKey();
+            final Source source = key.getSource();
+            final int lineNo = key.getLineNumber();
+            if (source != curSource) {
+                if (curSource != null) {
+                    while (curLineNo <= curSource.getLineCount()) {
+                        displayLine(out, null, curSource, curLineNo++);
+                    }
+                }
+                curSource = source;
+                curLineNo = 1;
+                out.println();
+                out.println(source.getPath());
+            }
+            while (curLineNo < lineNo) {
+                displayLine(out, null, curSource, curLineNo++);
+            }
+            displayLine(out, entry.getValue(), curSource, curLineNo++);
+        }
+        if (curSource != null) {
+            while (curLineNo <= curSource.getLineCount()) {
+                displayLine(out, null, curSource, curLineNo++);
+            }
+        }
+    }
+
+    private static void displayLine(PrintStream out, CoverageRecord record, Source source, int lineNo) {
+        if (record == null) {
+            out.format("%14s", " ");
+        } else {
+            out.format("(%12d)", record.count);
+        }
+        out.format(" %3d: ", lineNo);
+        out.println(source.getCode(lineNo));
+    }
+
+    /**
+     * A listener for events at each instrumented AST location. This listener counts
+     * "execution calls" to the instrumented node.
+     */
+    private final class CoverageRecord extends DefaultSimpleInstrumentListener {
+
+        private final SourceSection srcSection; // The text of the code being counted
+        private Instrument instrument;  // The attached Instrument, in case need to remove.
+        private long count = 0;
+
+        CoverageRecord(SourceSection srcSection) {
+            this.srcSection = srcSection;
+        }
+
+        @Override
+        public void enter(Probe probe) {
+            if (isEnabled()) {
+                count++;
+            }
+        }
+
+    }
+
+    private static final class LineLocationEntryComparator implements Comparator<Entry<LineLocation, CoverageRecord>> {
+
+        public int compare(Entry<LineLocation, CoverageRecord> e1, Entry<LineLocation, CoverageRecord> e2) {
+            return LineLocation.COMPARATOR.compare(e1.getKey(), e2.getKey());
+        }
+    }
+
+    /**
+     * Attach a counting instrument to each node that is assigned a specified tag.
+     */
+    private class CoverageProbeListener extends DefaultProbeListener {
+
+        @Override
+        public void probeTaggedAs(Probe probe, SyntaxTag tag, Object tagValue) {
+            if (countingTag == tag) {
+
+                final SourceSection srcSection = probe.getProbedSourceSection();
+                if (srcSection == null) {
+                    // TODO (mlvdv) report this?
+                } else if (!srcSection.getSource().isTaggedAs(Tags.NO_COVERAGE)) {
+                    // Get the source line where the
+                    final LineLocation lineLocation = srcSection.getLineLocation();
+                    CoverageRecord record = coverageMap.get(lineLocation);
+                    if (record != null) {
+                        // Another node starts on same line; count only the first (textually)
+                        if (srcSection.getCharIndex() > record.srcSection.getCharIndex()) {
+                            // Existing record, corresponds to code earlier on line
+                            return;
+                        } else {
+                            // Existing record, corresponds to code at a later position; replace it
+                            record.instrument.dispose();
+                        }
+                    }
+
+                    final CoverageRecord coverage = new CoverageRecord(srcSection);
+                    final Instrument instrument = Instrument.create(coverage, CoverageTracker.class.getSimpleName());
+                    coverage.instrument = instrument;
+                    instruments.add(instrument);
+                    probe.attach(instrument);
+                    coverageMap.put(lineLocation, coverage);
+                }
+            }
+        }
+    }
+
+}