--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jvmci/jdk.vm.ci.options/src/jdk/vm/ci/options/JVMCIJarsOptionDescriptorsProvider.java	Thu Oct 08 17:28:41 2015 -0700
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2014, 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 jdk.vm.ci.options;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.jar.JarFile;
+import java.util.zip.ZipEntry;
+
+import jdk.vm.ci.options.OptionsParser.OptionDescriptorsProvider;
+
+/**
+ * Access to the {@link OptionDescriptors} declared by
+ * {@code META-INF/services/jdk.vm.ci.options.OptionDescriptors} files in
+ * {@code <jre>/lib/jvmci/*.jar}.
+ */
+final class JVMCIJarsOptionDescriptorsProvider implements OptionDescriptorsProvider {
+
+    static final String OptionDescriptorsServiceFile = "META-INF/services/" + OptionDescriptors.class.getName();
+
+    private final Iterator<File> jars;
+    private final List<OptionDescriptors> optionsDescriptorsList;
+
+    /**
+     * Creates a {@link JVMCIJarsOptionDescriptorsProvider} if at least one JVMCI jar is available
+     * otherwise returns null.
+     */
+    static JVMCIJarsOptionDescriptorsProvider create() {
+        List<File> jarsList = findJVMCIJars();
+        if (jarsList.isEmpty()) {
+            return null;
+        }
+        return new JVMCIJarsOptionDescriptorsProvider(jarsList);
+    }
+
+    private JVMCIJarsOptionDescriptorsProvider(List<File> jarsList) {
+        this.jars = jarsList.iterator();
+        this.optionsDescriptorsList = new ArrayList<>(jarsList.size() * 3);
+    }
+
+    /**
+     * Finds the list of JVMCI jars.
+     */
+    private static List<File> findJVMCIJars() {
+        File javaHome = new File(System.getProperty("java.home"));
+        File lib = new File(javaHome, "lib");
+        File jvmci = new File(lib, "jvmci");
+        if (!jvmci.exists()) {
+            return Collections.emptyList();
+        }
+
+        List<File> jarFiles = new ArrayList<>();
+        for (String fileName : jvmci.list()) {
+            if (fileName.endsWith(".jar")) {
+                File file = new File(jvmci, fileName);
+                if (file.isDirectory()) {
+                    continue;
+                }
+                jarFiles.add(file);
+            }
+        }
+        return jarFiles;
+    }
+
+    public OptionDescriptor get(String name) {
+        // Look up loaded option descriptors first
+        for (OptionDescriptors optionDescriptors : optionsDescriptorsList) {
+            OptionDescriptor desc = optionDescriptors.get(name);
+            if (desc != null) {
+                return desc;
+            }
+        }
+        while (jars.hasNext()) {
+            File path = jars.next();
+            try (JarFile jar = new JarFile(path)) {
+                ZipEntry entry = jar.getEntry(OptionDescriptorsServiceFile);
+                if (entry != null) {
+                    BufferedReader br = new BufferedReader(new InputStreamReader(jar.getInputStream(entry)));
+                    String line = null;
+                    OptionDescriptor desc = null;
+                    while ((line = br.readLine()) != null) {
+                        OptionDescriptors options;
+                        try {
+                            options = (OptionDescriptors) Class.forName(line).newInstance();
+                            optionsDescriptorsList.add(options);
+                            if (desc == null) {
+                                desc = options.get(name);
+                            }
+                        } catch (Exception e) {
+                            throw new InternalError("Error instantiating class " + line + " read from " + path, e);
+                        }
+                    }
+                    if (desc != null) {
+                        return desc;
+                    }
+                }
+            } catch (IOException e) {
+                throw new InternalError("Error reading " + path, e);
+            }
+        }
+        return null;
+    }
+}