--- a/src/share/vm/oops/methodOop.cpp	Mon Apr 19 18:58:31 2010 -0400
+++ b/src/share/vm/oops/methodOop.cpp	Tue May 04 15:12:08 2010 -0400
@@ -1114,6 +1114,20 @@
     return ( a < b ? -1 : (a == b ? 0 : 1));
   }
 
+  // We implement special compare versions for narrow oops to avoid
+  // testing for UseCompressedOops on every comparison.
+  static int method_compare_narrow(narrowOop* a, narrowOop* b) {
+    methodOop m = (methodOop)oopDesc::load_decode_heap_oop(a);
+    methodOop n = (methodOop)oopDesc::load_decode_heap_oop(b);
+    return m->name()->fast_compare(n->name());
+  }
+
+  static int method_compare_narrow_idempotent(narrowOop* a, narrowOop* b) {
+    int i = method_compare_narrow(a, b);
+    if (i != 0) return i;
+    return ( a < b ? -1 : (a == b ? 0 : 1));
+  }
+
   typedef int (*compareFn)(const void*, const void*);
 }
 
@@ -1166,7 +1180,7 @@
 
     // Use a simple bubble sort for small number of methods since
     // qsort requires a functional pointer call for each comparison.
-    if (UseCompressedOops || length < 8) {
+    if (length < 8) {
       bool sorted = true;
       for (int i=length-1; i>0; i--) {
         for (int j=0; j<i; j++) {
@@ -1182,10 +1196,10 @@
           sorted = true;
       }
     } else {
-      // XXX This doesn't work for UseCompressedOops because the compare fn
-      // will have to decode the methodOop anyway making it not much faster
-      // than above.
-      compareFn compare = (compareFn) (idempotent ? method_compare_idempotent : method_compare);
+      compareFn compare =
+        (UseCompressedOops ?
+         (compareFn) (idempotent ? method_compare_narrow_idempotent : method_compare_narrow):
+         (compareFn) (idempotent ? method_compare_idempotent : method_compare));
       qsort(methods->base(), length, heapOopSize, compare);
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/runtime/6925573/SortMethodsTest.java	Tue May 04 15:12:08 2010 -0400
@@ -0,0 +1,190 @@
+/*
+ * Copyright 2008-2010 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import java.lang.reflect.Method;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.Vector;
+
+import javax.tools.Diagnostic;
+import javax.tools.DiagnosticCollector;
+import javax.tools.FileObject;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaCompiler.CompilationTask;
+import javax.tools.JavaFileManager;
+import javax.tools.JavaFileObject;
+import javax.tools.JavaFileObject.Kind;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.StandardJavaFileManager;
+import javax.tools.ToolProvider;
+
+/*
+ * @test SortMethodsTest
+ * @bug 6925573
+ * @summary verify that class loading does not need quadratic time with regard to the number of class
+methods.
+ * @run main SortMethodsTest
+ * @author volker.simonis@gmail.com
+*/
+
+public class SortMethodsTest {
+
+  static String createClass(String name, int nrOfMethods) {
+    StringWriter sw = new StringWriter();
+    PrintWriter pw = new PrintWriter(sw);
+    pw.println("public class " + name + "{");
+    for (int i = 0; i < nrOfMethods; i++) {
+      pw.println("  public void m" + i + "() {}");
+    }
+    pw.println("  public static String sayHello() {");
+    pw.println("    return \"Hello from class \" + " + name +
+               ".class.getName() + \" with \" + " + name +
+               ".class.getDeclaredMethods().length + \" methods\";");
+    pw.println("  }");
+    pw.println("}");
+    pw.close();
+    return sw.toString();
+  }
+
+  public static void main(String args[]) {
+
+    JavaCompiler comp = ToolProvider.getSystemJavaCompiler();
+    DiagnosticCollector<JavaFileObject> diags = new DiagnosticCollector<JavaFileObject>();
+    final String cName = new String("ManyMethodsClass");
+    Vector<Long> results = new Vector<Long>();
+
+    for (int i = 6; i < 600000; i*=10) {
+      String klass =  createClass(cName, i);
+      JavaMemoryFileObject file = new JavaMemoryFileObject(cName, klass);
+      MemoryFileManager mfm = new MemoryFileManager(comp.getStandardFileManager(diags, null, null), file);
+      CompilationTask task = comp.getTask(null, mfm, diags, null, null, Arrays.asList(file));
+
+      if (task.call()) {
+        try {
+          MemoryClassLoader mcl = new MemoryClassLoader(file);
+          long start = System.nanoTime();
+          Class<? extends Object> c = Class.forName(cName, true, mcl);
+          long end = System.nanoTime();
+          results.add(end - start);
+          Method m = c.getDeclaredMethod("sayHello", new Class[0]);
+          String ret = (String)m.invoke(null, new Object[0]);
+          System.out.println(ret + " (loaded and resloved in " + (end - start) + "ns)");
+        } catch (Exception e) {
+          System.err.println(e);
+        }
+      }
+      else {
+        System.out.println(klass);
+        System.out.println();
+        for (Diagnostic diag : diags.getDiagnostics()) {
+          System.out.println(diag.getCode() + "\n" + diag.getKind() + "\n" + diag.getPosition());
+          System.out.println(diag.getSource() + "\n" + diag.getMessage(null));
+        }
+      }
+    }
+
+    long lastRatio = 0;
+    for (int i = 2; i < results.size(); i++) {
+      long normalized1 = Math.max(results.get(i-1) - results.get(0), 1);
+      long normalized2 = Math.max(results.get(i) - results.get(0), 1);
+      long ratio = normalized2/normalized1;
+      lastRatio = ratio;
+      System.out.println("10 x more methods requires " + ratio + " x more time");
+    }
+    // The following is just vague estimation but seems to work on current x86_64 and sparcv9 machines
+    if (lastRatio > 80) {
+      throw new RuntimeException("ATTENTION: it seems that class loading needs quadratic time with regard to the number of class methods!!!");
+    }
+  }
+}
+
+class JavaMemoryFileObject extends SimpleJavaFileObject {
+
+  private final String code;
+  private ByteArrayOutputStream byteCode;
+
+  JavaMemoryFileObject(String name, String code) {
+    super(URI.create("string:///" + name.replace('.','/') + Kind.SOURCE.extension), Kind.SOURCE);
+    this.code = code;
+  }
+
+  @Override
+  public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+    return code;
+  }
+
+  @Override
+  public OutputStream openOutputStream() {
+    byteCode = new ByteArrayOutputStream();
+    return byteCode;
+  }
+
+  byte[] getByteCode() {
+    return byteCode.toByteArray();
+   }
+}
+
+class MemoryClassLoader extends ClassLoader {
+
+  private final JavaMemoryFileObject jfo;
+
+  public MemoryClassLoader(JavaMemoryFileObject jfo) {
+    this.jfo = jfo;
+  }
+
+  public Class findClass(String name) {
+    byte[] b = jfo.getByteCode();
+    return defineClass(name, b, 0, b.length);
+  }
+}
+
+class MemoryFileManager extends ForwardingJavaFileManager<JavaFileManager> {
+
+  private final JavaFileObject jfo;
+
+  public MemoryFileManager(StandardJavaFileManager jfm, JavaFileObject jfo) {
+    super(jfm);
+    this.jfo = jfo;
+  }
+
+  @Override
+  public FileObject getFileForInput(Location location, String packageName,
+                                    String relativeName) throws IOException {
+    return jfo;
+  }
+
+  @Override
+  public JavaFileObject getJavaFileForOutput(Location location, String qualifiedName,
+                                             Kind kind, FileObject outputFile) throws IOException {
+    return jfo;
+  }
+
+}