<div dir="ltr">Hi Tim,<div class="gmail_extra"><br><div class="gmail_quote">On Tue, May 12, 2015 at 7:59 AM, Tim Olson <span dir="ltr"><<a href="mailto:tim.olson.mail@gmail.com" target="_blank">tim.olson.mail@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class=""><br>
On May 12, 2015, at 3:10 AM, marcel.taeumel <<a href="mailto:Marcel.Taeumel@hpi.de">Marcel.Taeumel@hpi.de</a>> wrote:<br>
<br>
> I think that's only a symptom. Why else is the bug related to different VM<br>
> versions?<br>
<br>
</span>I ran into this and various variants of it a little while ago, when I tried to update my somewhat outdated image using the latest Cog VM. When I ran using an older interpreter VM, the build went fine.<br>
<br>
In tracking down one of the MNU failures I was seeing with the Cog build, I saw this:<br>
<br>
SmallInteger(Object) >> doesNotUnderstand: #isEmptyOrNil<br>
PluggableListMorphOfMany(PluggableListMorph) >> hasFilter<br>
<br>
where:<br>
<br>
hasFilter<br>
^ lastKeystrokes isEmptyOrNil not<br>
<br>
the debugger in the context of hasFilter says that lastKeystrokes is an empty ByteString, but when I click on self for the SmallInteger DNU, it says that the receiver is a SmallInteger 0.<br>
<br>
Looking at the object context of PluggableListMorphOfMany, I saw that the only SmallInteger 0 value was the instance variable “lastKeystrokeTime” just before “lastKeystrokes”.<br>
<br>
So it looks to me like there may be a (rare) instance variable to register mapping bug in the latest Cog VMs.<br></blockquote><div><br></div><div>Yes, very nearly. In fact it was a bug in new register allocation code for compiling #==. It is fixed in the r3343 VMs. Sorry for the inconvenience. <a href="http://www.mirandabanda.org/files/Cog/VM/VM.r3343">http://www.mirandabanda.org/files/Cog/VM/VM.r3343</a></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<span class="HOEnZb"><font color="#888888"><br>
— tim<br>
<br>
<br>
</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">best,<div>Eliot</div></div>
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