Re: Compiling with jikes > 1.13

[Mark Wielaard]

Hi,

On Wed, 2002-02-06 at 20:17, Tom Tromey wrote:
> >>>>> "Mark" == Mark Wielaard <address@hidden> writes:
> 
> Mark> I changed the program a little bit to force loading all classes
> Mark> through the same ClassLoader when possible. Now it actually
> Mark> seems to work. But a lot of the VerifyErrors seem to be wrong.
> 
> There are probably remaining bugs in the verifier.  I'm interested in
> killing these as quickly as possible.
>
> Mark> For example the verifier doesn't like something like the following:
> 
> I tried the appended example, which gives nearly identical bytecode.
> It worked fine for me :-(.  Could you try it?

That one works now for me. A friend (hi Erwin!) pointed out that my
program was a bit eager with respect to loading java.lang.Throwable and
java.lang.String through my ClassLoader. The verifier got confused about
wether those classes were really assignable to the reference type on the
stack (they were not since they had different ClassLoaders!).

> Thanks, I'll give it a try soon.

Here is a new version that just ignores all java.lang classes.
Still have to debug some more since the program now get
NullPointerExceptions and hangs again on some classes (seems that trying
to fool the SystemClassLoader is not a good idea :) But I have attached
the results so far. I will go through the VerifyErrors I get now to see
if they are real.

Cheers,

Mark

import java.io.*;

public class VerifyClass extends ClassLoader
{
    public static void main(String args[])
    {
      if (args.length == 1)
        {
          System.out.println("Verifying: " + args[0]);
          try
            {
              if (args[0].indexOf("java/lang/") < 0)
                {
                  VerifyClass verifier = new VerifyClass();
                  Class c = verifier.load(args[0]);
                  verifier.resolveClass(c);
                }
              else
                System.out.println("Skipping java.lang class");
            }
          catch (Throwable t)
            {
              System.out.println(t);
            }
        }
      else
        System.out.println("argument must be a class file");
    }

    Class load(String classFile) throws IOException
    {
      InputStream is = new FileInputStream(classFile);
      ByteArrayOutputStream os = new ByteArrayOutputStream();
      byte[] buf = new byte[2048];

      int read = is.read(buf);
      while(read > 0)
        {
          os.write(buf, 0, read);
          read = is.read(buf);
        }

      byte[] data = os.toByteArray();
      return defineClass(data, 0, data.length);
    }

    protected Class loadClass(String name, boolean link)
      throws java.lang.ClassNotFoundException
    {
      // System.out.println("Loading: " + name);
      if (!name.startsWith("java.lang"))
        {
          try
            {
              Class c = load(name.replace('.','/') + ".class");

              if (link)
                resolveClass(c);

              return c;
            }
          catch(IOException ioe) { }
        }
      return super.loadClass(name, link);
    }
}

Verifying: ./java/lang/VerifyError.class
java.lang.VerifyError: verification failed at PC 64 in 
java.util.Collections:shuffle((Ljava.util.List;Ljava.util.Random;)V): array 
required
java.lang.VerifyError: verification failed at PC 37 in 
java.util.zip.ZipFile:readEntries(()V): incompatible type on stack
java.lang.VerifyError: verification failed at PC 37 in 
java.util.zip.ZipFile:readEntries(()V): incompatible type on stack
java.lang.VerifyError: verification failed at PC 54 in 
java.net.InetAddress:checkCacheFor((Ljava.lang.String;)[Ljava.net.InetAddress;):
 array required
java.lang.VerifyError: verification failed at PC 82 in 
java.net.URLDecoder:decode((Ljava.lang.String;Ljava.lang.String;)Ljava.lang.String;):
 array type expected
java.lang.VerifyError: verification failed at PC 58 in 
java.text.NumberFormat:computeInstance((Ljava.util.Locale;Ljava.lang.String;Ljava.lang.String;)Ljava.text.NumberFormat;):
 incompatible return type
java.lang.VerifyError: verification failed at PC 961 in 
java.text.SimpleDateFormat:parse((Ljava.lang.String;Ljava.text.ParsePosition;)Ljava.util.Date;):
 array type expected
java.lang.VerifyError: verification failed at PC 163 in 
java.text.AttributedString:<init>((Ljava.text.AttributedCharacterIterator;II[Ljava.text.AttributedCharacterIterator$Attribute;)V):
 incompatible type on stack
java.lang.VerifyError: verification failed at PC 58 in 
java.text.NumberFormat:computeInstance((Ljava.util.Locale;Ljava.lang.String;Ljava.lang.String;)Ljava.text.NumberFormat;):
 incompatible return type
java.lang.VerifyError: verification failed at PC 12 in 
java.beans.beancontext.BeanContextChildSupport:<init>((Ljava.beans.beancontext.BeanContextChild;)V):
 incompatible type on stack
java.lang.VerifyError: verification failed at PC 20 in 
java.rmi.server.ObjID:<init>(()V): incompatible type on stack
java.lang.VerifyError: verification failed at PC 43 in 
gnu.java.rmi.server.UnicastConnectionManager:getInstance((Ljava.lang.String;ILjava.rmi.server.RMIClientSocketFactory;)Lgnu.java.rmi.server.UnicastConnectionManager;):
 incompatible type on stack