[squeak-dev] Re: Bug in BytecodeGenerator>>#jump:if:

nice ncellier at ifrance.com
Sun Jun 22 16:17:45 UTC 2008

Klaus D. Witzel wrote:
> On Sun, 22 Jun 2008 17:16:37 +0200, Nicolas wrote:
>> So what would you assert about longJumpIfFalseTest?
> ;)
>> We could assert that trying to compile such a method should raise an 
>> Exception (let's say a ByteCodeLimitException).
> No, I wouldn't do that. I'd wrap the instance of CompiledMethod into an 
> InstructionStream using temps | is msg | and check it on the meta level, 
> without executing the method and without the possibility that this 
> crashes the VM, like
>  (msg := is nextInstruction) selector == #pushConstant: and: [msg 
> arguments = #(true)].
>  (msg := is nextInstruction) selector == #jump:if: and:  [msg arguments 
> = #(offset false)]
> where offset is the one expected.
> /Klaus

Thanks, that's a nice alternative which is future proof toward Bytecode 
definition change.

However, i have two objections:
1) the test would still not pass if i install a handler that can 
overcome ByteCodeLimitException
2) the test won't avoid para-phrasing ByteCodeGenerator job. Because you 
need to calculate the offset...

In other words, I would always prefer higher level tests if possible 
(like asserting the result of execution of ifTrue:ifFalse:).


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