Description ulf.brosziewski 2009-01-06 04:30:16 EST

To reproduce the bug, compile the following class (compliance level 1.6) and
run its main method with
   java -XX:-FailOverToOldVerifier StackMapBug

public class StackMapBug {
   
   private static void dummy(Class<?> c, int n) { }

   public static void main(String... args) {
      dummy(Integer.class, (args == null ? -1 : 1));
   }
}

The JVM (JDK 1.6.0_10, Win32) exits with
Exception in thread "main" java.lang.VerifyError: Inconsistent stackmap frames
at branch target 10 in method StackMapBug.main([Ljava/lang/String;)V at offset 3

In the two stackmap frames for the main method, the type of the first stack
item is specified as java/lang/Integer (instead of java/lang/Class). Here is
a part of the javap output for the example class:

  StackMapTable: number_of_entries = 2
   frame_type = 74 /* same_locals_1_stack_item */
     stack = [ class java/lang/Integer ]
   frame_type = 255 /* full_frame */
     offset_delta = 0
     locals = [ class "[Ljava/lang/String;" ]
     stack = [ class java/lang/Integer, int ]