Description Dave Liu 2007-04-25 15:47:12 EDT

Compiling the following enum using Eclipse 3.3 M6:

public enum TestEnum {
	C { @Override public boolean test() { return true; } };

	static {
		for (int i = 0; i < 1; i++) {
		}
	}
	
	public boolean test() {
		return false;
	}
}

Produces the following static initializer with an incorrect stackmap:

static {};
  Code:
   Stack=6, Locals=1, Args_size=0
   0:   new     #12; //class TestEnum$1
   3:   dup
   4:   ldc     #14; //String C
   6:   iconst_0
   7:   invokespecial   #15; //Method TestEnum$1."<init>":(Ljava/lang/String;I)V
   10:  putstatic       #19; //Field C:LTestEnum;
   13:  iconst_1
   14:  anewarray       #1; //class TestEnum
   17:  dup
   18:  iconst_0
   19:  getstatic       #19; //Field C:LTestEnum;
   22:  aastore
   23:  putstatic       #21; //Field ENUM$VALUES:[LTestEnum;
   26:  iconst_0
   27:  istore_0
   28:  goto    34
   31:  iinc    0, 1
   34:  iload_0
   35:  iconst_1
   36:  if_icmplt       31
   39:  return
  LineNumberTable: 
   line 3: 0
   line 6: 26
   line 2: 39

  LocalVariableTable: 
   Start  Length  Slot  Name   Signature
   28      11      0    i       I

  StackMapTable: number_of_entries = 2
   frame_type = 255 /* full_frame */
     offset_delta = 31
     locals = [ int ]
     stack = [ uninitialized 0, uninitialized 0 ]
   frame_type = 255 /* full_frame */
     offset_delta = 2
     locals = [ int ]
     stack = [ uninitialized 0, uninitialized 0 ]

This stackmap fails to verify:

bin> java -XX:-FailOverToOldVerifier -classpath . TestEnum
Exception in thread "main" java.lang.VerifyError: Inconsistent stackmap frames at branch target 34 in method TestEnum.<clinit>()V at offset 28

If the overridden method "test" is removed from "C", then the problem disappears.