is this correct code?

Hi all,

I am currently trying to find an bytecode problem in a strange 
situation. The code is fine if verified and normally run, but fails if 
debugged in IntelliJ with:

java.lang.VerifyError: (class: 
org/codehaus/groovy/ast/builder/AstBuilderTransformation, method: 
<clinit> signature: ()V) Attempt to split long or double on the stack

No clinit looks like this:

>   static <clinit>()V
>     LDC 0
>     INVOKESTATIC org/codehaus/groovy/runtime/typehandling/DefaultTypeTransformation.box (J)Ljava/lang/Object;
>     CHECKCAST java/lang/Long
>     ASTORE 0
>     ALOAD 0
>     INVOKESTATIC org/codehaus/groovy/runtime/typehandling/DefaultTypeTransformation.longUnbox (Ljava/lang/Object;)J
>     PUTSTATIC org/codehaus/groovy/ast/builder/AstBuilderTransformation.__timeStamp__239_neverHappen1291891067850 : J
>     ALOAD 0
>     POP
>     LDC 1291891067849
>     INVOKESTATIC org/codehaus/groovy/runtime/typehandling/DefaultTypeTransformation.box (J)Ljava/lang/Object;
>     CHECKCAST java/lang/Long
>     ASTORE 1
>     ALOAD 1
>     INVOKESTATIC org/codehaus/groovy/runtime/typehandling/DefaultTypeTransformation.longUnbox (Ljava/lang/Object;)J
>     PUTSTATIC org/codehaus/groovy/ast/builder/AstBuilderTransformation.__timeStamp : J
>     ALOAD 1
>     POP
>     RETURN
>     RETURN
>     NOP
>     MAXSTACK = 2
>     MAXLOCALS = 2

And I see two potential problems.

First there is the LDC 1291891067849, which should produce an int or 
long? I quite never understood how a constant can be long and int at the 
same time here. Anyway, next is a method call that takes an long and we 
may or may not have one. Now I know that there is actually no way to 
represent a real long constant over 1l, so this is probably right and 
what the java compiler would have done as well.

But before that there is also a LDC 0 followed by a box call that takes 
a long. This is the only place I can imagine could cause a problem. And 
I recently had the case that I did "LDC 0; LSTORE 5" and the verifier 
complained... sometimes. I could fix it there by instead having 
"LCONST_0; LSTORE 5".

Now I am wondering about some things:
(1) why is it valid to use LDC one time and at another not?
(2) if it is not valid, why is it sometimes a VerifyError and sometimes not?
(3) shouldn't asm do a strict check here (I am using asm 3.2) and point 
this out as error?

bye blackdrag

-- 
Jochen "blackdrag" Theodorou
The Groovy Project Tech Lead
http://blackdragsview.blogspot.com/
For Groovy programming sources visit http://groovy.codehaus.org

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