[Vm-dev] Something weird with prim 83/84/100

[Eliot Miranda]

Hi Boris,

   in trunk Squeak 6.1 alpha, VM Open Smalltalk Cog[Spur] VM
[CoInterpreterPrimitives VMMaker.oscog-eem.3256] 5.20221022.0042, I get the
debugger both ways. Both routes, testDirect & testIndirect result in a
notifier failing in primitives 83, 84 & 100.  The failure code for
#100, Object>>#perform:withArguments:inSuperclass:, infers that the number
of arguments is incorrect.

When I modify the source of these methods to include the primitive error
code then in each failure the VM correctly supplies the #'bad number of
arguments' error code.

So I see a correct system.  I'm not seeing what you're seeing.

On Fri, Oct 21, 2022 at 6:54 AM Boris Shingarov <boris at shingarov.com> wrote:

>  Dear fellow VM hackers:
> There is something about the #perform: prims I do not understand.
>
> If I send #perform: not giving it enough arguments, I would expect the
> primitive to fail through to the Smalltalk code in
> Object>>perform:withArguments:inSuperclass:.
>
> But, sometimes it's indeed what happens and sometimes it's not what
> happens.  In the attached test , if you run testDirect (in this
> morning's Squeak6) you will end up in the debugger (expected), but if
> you wrap in an extra send such as testIndirect, the prim will pass nil
> for the missing argument (to me this is unexpected).  I also tested in
> last night's build of Cuis, and in Pharo8 (in the latter, the behavior
> is even weirder: if you replace the fail code to answer #somethingElse,
> you get #(somethingElse false false) instead of the #(false false false)
> in Squeak).
>
> Anyone has any thoughts on this?
>


-- 
_,,,^..^,,,_
best, Eliot
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