I can't check it on Squeak anymore. Squeak not works on Mac Sierra for me.

I attach crash file. When I try it second time. After step over I got DNU error which shows very strange thing that 0 integer was sent as message. And when I click on basicSize method image crashed. Then I try to get same behaviour but can't. Image crash when I press step over debugger button. (dump file about this case)

2016-12-05 14:33 GMT+01:00 David T. Lewis lewis@mail.msen.com:

On Mon, Dec 05, 2016 at 01:10:28PM +0100, Denis Kudriashov wrote:

...

Hi.

I just remind about it

2016-04-15 15:42 GMT+02:00 Denis Kudriashov dionisiydk@gmail.com:

...

Hi

In debugger (Squeak or Pharo) try "step over" for expression "Object basicSize": image will crash.

I just tried on Squeak 64 bit Spur and no crash. Is there a specific VM version that has the problem?

Dave

...

...

We have opened issue for this in Pharo tracker 17962 <https://pharo.fogbugz.com/f/cases/17962/Image-is-crashed-

when-step-over-Object-basicSize-in-debugger>

...

...

I found automated way how to check problem:

p := [ Object basicSize ] fork. p suspend.

3 timesRepeat: [p step: p suspendedContext]. newContext := p completeStep: p suspendedContext. newContext selector. "=> doesNotUnderstand:" newContext arguments first selector == 0

2016-12-05 15:08 GMT+01:00 Denis Kudriashov dionisiydk@gmail.com:

2016-12-05 15:07 GMT+01:00 Denis Kudriashov dionisiydk@gmail.com:

...

I attach crash file. When I try it second time. After step over I got DNU error which shows very strange thing that 0 integer was sent as message. And when I click on basicSize method image crashed. Then I try to get same behaviour but can't. Image crash when I press step over debugger button. (dump file about this case)

It is on one of latest pharo 6 image and mac os VM (dump includes this information I guess)

Hi Denis,

On Mon, Dec 5, 2016 at 6:29 AM, Denis Kudriashov dionisiydk@gmail.com wrote:

2016-12-05 15:25 GMT+01:00 Denis Kudriashov dionisiydk@gmail.com:

...

I found automated way how to check problem:

p := [ Object basicSize ] fork. p suspend.

3 timesRepeat: [p step: p suspendedContext]. newContext := p completeStep: p suspendedContext. newContext selector. "=> doesNotUnderstand:" newContext arguments first selector == 0

Thanks. This reproduces in the simulator. The interpreter is accessing byte codes beyond the return at the end of Object>>#basicSize. I should be bale to understand this better soon.

And arguments of DNU message argument is also very strange:

newContext arguments first arguments "an Array(0 Context>>jump)"

2016-12-08 23:44 GMT+01:00 Eliot Miranda eliot.miranda@gmail.com:

Hi Denis,

this is fixed in VMMaker.oscog-eem.2032.  I'll generate sources and

push to github presently. Thanks for the test case. This is a "new" case the VM has to deal with with the "new" callPrimitive byte code. I had written the code to handle the case quite a while ago (2013?) but had written incorrect code.

Thank's Eliot.

2016-12-05 17:20 GMT+01:00 Levente Uzonyi leves@caesar.elte.hu:

Don't be that naive. Just because the executable is called Pharo, it's still a Squeak VM. You can open a Squeak image with it.

Thank's Levente. I not thought about it :)

No I tried 32 bits squeak with "some" Pharo vm for MacOS Sierra. Both squeak 5.1 and trunk 6 are crashed. And they are crashed also with my example at line with #completeStep:. (Pharo has different implementation I guess) Dump file attached for squeak 6 case