libgcj/5782: prims.cc produces null pointer while allocating an uninitialized object

libgcj/5782: prims.cc produces null pointer while allocating an uninitialized object

[toddastock]

>Number:         5782
>Category:       libgcj
>Synopsis:       prims.cc null pointer while allocating an unitialized object.
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 25 19:56:02 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     
>Release:        3.1 20020225 (experimental)
>Organization:
>Environment:
System: Linux escher 2.4.9-21 #1 Thu Jan 17 14:16:30 EST 2002 i686 unknown
Architecture: i686

	
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ./configure --enable-threads=posix --prefix=/home/tstock/local --disable-shared --enable-languages=c++,java : (reconfigured)  : (reconfigured) 
>Description:
In prims.cc it's possible to reach _Jv_AllocObjectNoFinalizer with class size equal to zero.  Thus causing the _Jv_AllocObj to fail and throw a null pointer exception.
Nothing prior to the NestedCreater.create() call in the test case initializes the class TestDecl2 so the size is zero.  It's initialized upon entering _Jv_AllocObjectNoFinalizer, but the size field is not re-read.
>How-To-Repeat:
File: Test.java:
========================================
import java.io.*;
import java.util.*;
import java.lang.reflect.*;

public class Test
  {

  static Class clz = null;

  public static void main (String[] args)
    {

      Test t = new Test( );
      try
        {
	  clz = Class.forName( "TestDecl1" );
          t.doit( clz );
        }
      catch( ClassNotFoundException e )
        {
        }
    }

  interface NestedCreator
    {
      public Object create(Object parent)
          throws InvocationTargetException, IllegalAccessException, InstantiationException;
    }

  public void doit (final Class bean)
    {
      NestedCreator creator = null;
      try
        {
          Method[] methods = bean.getMethods();
          for( int i=0; i<methods.length; i++ )
            {
              final Method m = methods[i];
              final String name = m.getName();

              if( ! "dummy".equals(name) ) continue;

              Class[] args = m.getParameterTypes();
              final Constructor c = args[0].getConstructor(new Class[] {});
              creator = new NestedCreator()
                {
                  public Object create(Object parent)
                    throws InvocationTargetException, IllegalAccessException, InstantiationException
                    {
                      Object o = c.newInstance(new Object[] {});
                      m.invoke(parent, new Object[] {o});
                      return o;
                    }
                 };
            }
        }
      catch( NoSuchMethodException nse )
        {
        }

      try
        {
// Throws NullPointerException
          System.err.println("create="+creator.create( Test.clz.newInstance() ));
        }
      catch( IllegalAccessException e )
        {
        }
      catch( InstantiationException e )
        {
        }
      catch( InvocationTargetException e )
        {
        }
    }
  }
File: TestDecl1.java:
========================================
public class TestDecl1 extends TestDecl {

}
File: TestDecl2.java:
========================================
public class TestDecl2 extends TestDecl {

}
File: TestDecl.java:
========================================
public abstract class TestDecl {

  public void dummy( TestDecl2 o )
    {
      System.err.println("dummy");
    }
}
>Fix:
This may not be the appropriate fix for the problem.  Possibly you would want to run _Jv_InitClass prior to entering the _Jv_AllocObjectNoFinalizer.
Index: prims.cc
===================================================================
RCS file: /cvsroot/gcc/gcc/libjava/prims.cc,v
retrieving revision 1.71
diff -u -r1.71 prims.cc
--- prims.cc	7 Feb 2002 18:59:50 -0000	1.71
+++ prims.cc	26 Feb 2002 03:00:17 -0000
@@ -381,6 +381,7 @@
 _Jv_AllocObjectNoFinalizer (jclass klass, jint size)
 {
   _Jv_InitClass (klass);
+  if( size == 0 ) size = klass->size();
   jobject obj = (jobject) _Jv_AllocObj (size, klass);
   jvmpi_notify_alloc (klass, size, obj);
   return obj;
>Release-Note:
>Audit-Trail:
>Unformatted: