[armedbear-devel] Questions about r14452 (Fix cl-cont)

Rudolf Schlatte rudi at constantly.at
Tue Apr 2 18:08:44 UTC 2013

What makes me suspicious is the output of
    (describe (make-instance 'funcallable-standard-object))
    (describe (make-instance 'standard-generic-function))

There's a layout called layoutFuncallableStandardClass, defined in StandardClass.java, which has NAME as first slot, but that's for class objects with metaclass funcallable-standard-class, not for instances of these classes.  I'll think a bit in the next days and try to either resolve my doubts or come up with another fix for the problem.  Maybe I'm simply confused; wouldn't be the first time.  :)


On Apr 2, 2013, at 19:52, Erik Huelsmann <ehuels at gmail.com> wrote:

> Hi Rudi,
> Basically the expectation we violated was the fact that %set-lambda-name didn't want to take a funcallable instance as its function argument. The commit changed that and used the first slot  of the funcallable  instance class layout (called NAME) to store the name. I guess we forget to finalize the class somewhere, so the spots don't appear?
> Bye,
> Erik.
> sent from my phone
> On Apr 2, 2013 7:32 PM, "Rudolf Schlatte" <rudi at constantly.at> wrote:
> Hi,
> I suspect that the changes in commit r14452 only work by accident.
> The definions of SLOT_INDEX_NAME in FuncallableStandardClass vs FuncallableStandardObject are no problem, since the latter simply isn't used anywhere.  But the new methods getName() and setName() assume that a) the FuncallableStandardObject instance has at least one slot, and b) that slot holds a name.  Since
>     (class-slots (find-class 'funcallable-standard-object))
> returns NIL, these assumptions hold only when the objects are in fact generic functions.
> Amusingly,
>     (function-lambda-expression (make-instance 'funcallable-standard-object))
> runs into the type error on line 2666 of Primitives.lisp ("The value #<FUNCALLABLE-STANDARD-OBJECT {665C5A83}> is not of type FUNCTION.") even though
>     (typep (make-instance 'funcallable-standard-object) 'function) => T
> so I can't trigger the array-out-of-bounds error right now.
> Could I have a recipe for triggering the bug?  I'd like to see how cl-cont uses funcallable-standard-objects, and what expectations we violate.  I believe I can fix this properly.
> Cheers,
> Rudi

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.common-lisp.net/pipermail/armedbear-devel/attachments/20130402/6d4b0bcd/attachment.html>

More information about the armedbear-devel mailing list