libgcj/5695: verify.cc test that target is an object before running down interfaces

[toddastock at yahoo dot com]

>Number:         5695
>Category:       libgcj
>Synopsis:       verify.cc test that target is an object before running down interfaces
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Feb 14 18:26:00 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     
>Release:        3.1 20020214 (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
>Description:
verify.cc test that target is an object before running down interfaces.  Based on the prior bug (5670)
>How-To-Repeat:
import java.io.*;
import java.util.*;

public class Test2
  {
  Vector v = new Vector( );
  public void addBuildListener( TestListener l )
    {
      v.addElement( l );
    }
  }
import java.io.*;
import java.util.*;

public class Test
  {
  Object x = null;
  int y = 0;

  public static void main (String[] args)
    {

      Test t = new Test( );
      try
        {
          t.doit( );
        }
      catch( Exception e )
        {
        }
    }

  private void doit( ) throws Exception
    {
      final Test2 t = new Test2();
      addListener(t);
    }

  protected void addListener( Test2 t )
    {
      t.addBuildListener(doitSub());
    }

  private TestLogger testE () throws IOException
    {
      return new TestLoggerDefault();
    }

  private TestLogger doitSub ()
    {
      TestLogger logger = null;
      if( x != null )
        {
          try
          {
            logger = testE();
          }
          catch( IOException e )
          {
            throw new RuntimeException( );
          }
          catch( Exception e )
          {
            throw new RuntimeException( );
          }
        }
      else
        {
          logger = new TestLoggerDefault( );
        }
  
      logger.print(y);
      return logger;
    }
  }
public interface TestListener
  {
  }
public class TestLoggerDefault implements TestLogger
  {

  public void print ( int y )
    {
    }

  }
public interface TestLogger extends TestListener
  {
  void print ( int y );
  }
>Fix:
Reorder to check if target is an Object prior to running down the sources interface chain.
Index: verify.cc
===================================================================
RCS file: /cvsroot/gcc/gcc/libjava/verify.cc,v
retrieving revision 1.37
diff -u -r1.37 verify.cc
--- verify.cc	14 Feb 2002 17:48:36 -0000	1.37
+++ verify.cc	15 Feb 2002 02:16:54 -0000
@@ -245,7 +245,13 @@
 	// interface even if it hasn't been prepared.
 	else if ((target->state > JV_STATE_LINKED || target->isInterface ())
 		 && source->state > JV_STATE_LINKED)
+	  {
 	  return _Jv_IsAssignableFrom (target, source);
+	  }
+	else if (target == &java::lang::Object::class$)
+	  {
+	  return true;
+          }
 	else if (target->isInterface ())
 	  {
 	    for (int i = 0; i < source->interface_count; ++i)
@@ -272,10 +278,10 @@
 	    if (target == NULL)
 	      return false;
 	  }
-	else if (target == &java::lang::Object::class$)
-	  return true;
 	else if (source == &java::lang::Object::class$)
+	  {
 	  return false;
+	  }
 	else
 	  source = source->getSuperclass ();
       }
>Release-Note:
>Audit-Trail:
>Unformatted: