[Vm-dev] Re: Method executing but not sent to the receiver

Mariano Martinez Peck marianopeck at gmail.com
Tue Apr 26 14:31:53 UTC 2011


On Tue, Apr 26, 2011 at 12:50 PM, Henrik Sperre Johansen <
henrik.s.johansen at veloxit.no> wrote:

>
> Say you have Class A:
> inst vars : one two three
>
> and method compiled on it:
> foo
> ^one
>
> Then you also have Class B:
> inst vars: three two one
>
> Then you do
> methodFoo := A >> #foo
> methodFoo executeWithReceiver: B new one: 1; three: 3; yourself arguments:
> #()
>
> It'll return 3, which'll probably confuse those not very familiar with the
> bytecodes.
>
> Or using a class with no instvars, it'll crash in a similar manner to what
> you get if you currently do:
> Test methodDictionary at: #foo put: MCPackage >> #packageInfo.
> Test >> #foo.
> Test new foo
>

You see, now I got it :)  I am just slow.
Thanks Henrik for this example. In fact, it was not even obvious for me
until you told me. The "problem" is that the bytecodes to access/set
instanceVariables work by position instead of name, no?
I mean, 'one' is never put in the literals of A >> #foo

Nevertheless, exactly the same happens with #valueWithReceiver:arguments:
so...ok, we have this problem but we also have from before ;)
right ?

solutions?

First I would put a nice comment in #valueWithReceiver:arguments:   and
#valueWithReceiver:arguments:

Second, if I understood you correctly you mean to do in your previous email,
you want to validate that the class of the receiver is the same as the class
where the CompiledMethod is installed and if it is not, throw an error ?

On the one hand that would limit a bit the usage because that fails only
when there is instance var access, doesn't it?  On the other hand, it
prevents some crashes or weird cases where the results are not the expected
ones.

Opinions?



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> --
> View this message in context:
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> Sent from the Squeak VM mailing list archive at Nabble.com.
>



-- 
Mariano
http://marianopeck.wordpress.com
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