Squeak-dev August 2012

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Next meeting
by Colin Putney 01 Sep '12

01 Sep '12

Let's do it again! https://plus.google.com/u/0/events/c0nfhlfod6ogn3aumsq6seda7g8/102275780496…

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Daily Commit Log
by commits＠source.squeak.org 01 Sep '12

01 Sep '12

Changes to Trunk (http://source.squeak.org/trunk.html) in the last 24 hours: http://lists.squeakfoundation.org/pipermail/packages/2012-August/005489.html Name: KernelTests-nice.231 Ancestors: KernelTests-cmm.230 Add a test for (1<<63) negated arithmetic bugs =============================================

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Re: [squeak-dev] The Trunk: KernelTests-nice.231.mcz
by David T. Lewis 01 Sep '12

01 Sep '12

This turns out to be an exceptionally well written test. Some of the expressions in the test will crash a VM that is compiled in 64 bit mode. But the test fails before reaching that point, so it correctly identifies the problem in the VM without actually crashing the the VM. Excellent :) Dave On Fri, Aug 31, 2012 at 09:01:39PM +0000, commits(a)source.squeak.org wrote: > Nicolas Cellier uploaded a new version of KernelTests to project The Trunk: > http://source.squeak.org/trunk/KernelTests-nice.231.mcz > > ==================== Summary ==================== > > Name: KernelTests-nice.231 > Author: nice > Time: 31 August 2012, 11:01:26.531 pm > UUID: fb87513c-6c77-42a4-bd01-2d2b12acf8b8 > Ancestors: KernelTests-cmm.230 > > Add a test for (1<<63) negated arithmetic bugs > > =============== Diff against KernelTests-cmm.230 =============== > > Item was added: > + ----- Method: LargeNegativeIntegerTest>>testMinimumNegativeIntegerArithmetic (in category 'tests') ----- > + testMinimumNegativeIntegerArithmetic > + "We are speaking of minimum integer in underlying hardware here. > + In 2-complement, abs(INT_MIN) = (INT-MAX+1) and thus overflows hardware register. > + Since some old VM forgot this edge case they may fail and it's better to be aware of it. > + http://code.google.com/p/cog/issues/detail?id=92 > + http://bugs.squeak.org/view.php?id=7705 > + We only test the cases of 32 and 64 bit signed integers." > + > + #(32 64) do: [:nBits | > + | largePositiveInt largeNegativeInt | > + largePositiveInt := (1 << (nBits - 1)). > + largeNegativeInt := largePositiveInt negated. > + self assert: (largeNegativeInt >> 3) equals: (largeNegativeInt bitInvert >> 3) bitInvert. > + self assert: (largeNegativeInt + 1) equals: (largePositiveInt - 1) negated. > + self assert: (largeNegativeInt - -1) equals: (largePositiveInt - 1) negated. > + self assert: (largeNegativeInt // -1) equals: largePositiveInt. > + self assert: (largeNegativeInt \\ -1) equals: 0. > + self assert: (largeNegativeInt rem: -1) equals: 0. > + self assert: (largeNegativeInt quo: -1) equals: largePositiveInt. > + self assert: (largeNegativeInt * -1) equals: largePositiveInt. > + self assert: (largeNegativeInt / -1) equals: largePositiveInt]! >

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The Trunk: KernelTests-nice.231.mcz
by commits＠source.squeak.org 31 Aug '12

31 Aug '12

Nicolas Cellier uploaded a new version of KernelTests to project The Trunk: http://source.squeak.org/trunk/KernelTests-nice.231.mcz ==================== Summary ==================== Name: KernelTests-nice.231 Author: nice Time: 31 August 2012, 11:01:26.531 pm UUID: fb87513c-6c77-42a4-bd01-2d2b12acf8b8 Ancestors: KernelTests-cmm.230 Add a test for (1<<63) negated arithmetic bugs =============== Diff against KernelTests-cmm.230 =============== Item was added: + ----- Method: LargeNegativeIntegerTest>>testMinimumNegativeIntegerArithmetic (in category 'tests') ----- + testMinimumNegativeIntegerArithmetic + "We are speaking of minimum integer in underlying hardware here. + In 2-complement, abs(INT_MIN) = (INT-MAX+1) and thus overflows hardware register. + Since some old VM forgot this edge case they may fail and it's better to be aware of it. + http://code.google.com/p/cog/issues/detail?id=92 + http://bugs.squeak.org/view.php?id=7705 + We only test the cases of 32 and 64 bit signed integers." + + #(32 64) do: [:nBits | + | largePositiveInt largeNegativeInt | + largePositiveInt := (1 << (nBits - 1)). + largeNegativeInt := largePositiveInt negated. + self assert: (largeNegativeInt >> 3) equals: (largeNegativeInt bitInvert >> 3) bitInvert. + self assert: (largeNegativeInt + 1) equals: (largePositiveInt - 1) negated. + self assert: (largeNegativeInt - -1) equals: (largePositiveInt - 1) negated. + self assert: (largeNegativeInt // -1) equals: largePositiveInt. + self assert: (largeNegativeInt \\ -1) equals: 0. + self assert: (largeNegativeInt rem: -1) equals: 0. + self assert: (largeNegativeInt quo: -1) equals: largePositiveInt. + self assert: (largeNegativeInt * -1) equals: largePositiveInt. + self assert: (largeNegativeInt / -1) equals: largePositiveInt]!

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Community meeting
by Colin Putney 31 Aug '12

31 Aug '12

Hi all, Thanks to everyone who came out to the community meeting yesterday! I had some <cough> technical difficulties <cough>, and was late, but I did catch the last hour or so. It was great to put faces to names and meet people, and just see where the conversation went! Colin

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minor update to OMeta2
by Hans-Martin Mosner 31 Aug '12

31 Aug '12

Hi folks, there was a long-standing bug in decompiling OMeta2 rule methods. Today I found some time at Camp Smalltalk to look at it and could at least produce a version that does not raise exceptions when decompiling (it still prints only numbered temporaries, as it is not able to fetch the names from the generated source). Free free to update using http://www.squeaksource.com/OMeta/OMeta2-hmm.1.mcm Cheers, Hans-Martin

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An Apology
by Casey Ransberger 31 Aug '12

31 Aug '12

Hello everyone. I was distressed when I wrote my farewell. I came off as a total jerk. I'm sorry. Shit happened. Some friends of mine, who were in my favorite band, were gunned down. I'm still dealing with it. It's still not easy to talk about. I want to say: the people on this list are rare, brilliant, and beautiful. Don't ever stop doing what you do, don't ever stop believing in what you believe, and never stop fighting for the causes that matter to you. Life is really short. We don't get a lot of time. Some of us get more time than others. It's not always clear what to do, but we should use the time that we have to improve the lot for everyone else, and more so, for the kids who will follow us into the unknown. I have met more wonderful people on this list than I can count on my fingers and toes. I've learned more than I realized at the outset was to be learned from you. Thank you. Is what I should have said. I hope that some day soon, I'll be able to contribute something to the Smalltalk community, but for now, I have to go rest and heal. And play my guitar. Farewell for now, Casey

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List-Mod Bailing
by Casey Ransberger 29 Aug '12

29 Aug '12

</duncareanymore> Also, don't often have regular access to the Internet. CRAIG; you said you'd do it. I can't usually get access to the Internet anymore, so I'm a duck on one leg at moderating the list. Can't do it anymore. You volunteered. Do it. Start tomorrow. Realize that you're doing something that matters. I HAVE TO GO NOW, AT LEAST FOR AWHILE. I love all of you, but I have to deal with real life for awhile. I'm not waiting anymore. Farewell for now. All of you beautiful people. All the love. Etcetera. C On Aug 28, 2012, at 10:52 PM, AMS <arisadq(a)gmail.com> wrote: > Guys! I need min 20 responses in order to be able to use it in IBM SPSS modular. Your participation is highly appreciated. > > On Wednesday, 29 August 2012 04:50:58 UTC+1, AMS wrote: > Hi all, > > I have designed a short questionnaire for the purpose of my MSc project. Would you kindly spare few minutes to participate in. > > Purpose of questionnaire: > > This questionnaire is part of an MSc IT Project Management major project investigating the development of trust between virtual project team members.We are seeking the views of managers and team members who have experience in both virtual and traditional project team settings. > > If you take part in the questionnaire and provide us with your email address we shall share our findings with you. > > Here is the link: > > http://kwiksurveys.com/s.asp?sid=6iop4uh3snwm5tr4984 > > Kind regards, > Ary

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Fwd: doesn't Primitive 33 primitiveQuoLargeIntegers relies on C Undefined Behaviour ? uncover a BUG in Primitive 32 primitiveDivLargeIntegers and maybe some others
by Nicolas Cellier 29 Aug '12

29 Aug '12

Sorry to post here, this bounced at vm-dev But I think it's important Nicolas ---------- Forwarded message ---------- From: Nicolas Cellier <nicolas.cellier.aka.nice(a)gmail.com> Date: 2012/8/28 Subject: doesn't Primitive 33 primitiveQuoLargeIntegers relies on C Undefined Behaviour ? uncover a BUG in Primitive 32 primitiveDivLargeIntegers and maybe some others To: vm-dev-request(a)lists.squeakfoundation.org (1 << 63) negated is converted to signed long long 0x8000000000000000LL by signed64BitValueOf: So far so good... Then in primitiveQuoLargeIntegers, we will try to take absolute value of this beast... integerRcvr > 0 ifTrue: [ integerArg > 0 ifTrue: [result := integerRcvr // integerArg] ifFalse: [result := 0 - (integerRcvr // (0 - integerArg))]. ] ifFalse: [ integerArg > 0 ifTrue: [result := 0 - ((0 - integerRcvr) // integerArg)] ifFalse: [result := (0 - integerRcvr) // (0 - integerArg)]. ]. That is translated straightfully in C... sqLong integerArg; sqLong integerRcvr; sqLong result; snip... if (integerRcvr > 0) { if (integerArg > 0) { result = integerRcvr / integerArg; } else { result = 0 - (integerRcvr / (0 - integerArg)); } } else { if (integerArg > 0) { result = 0 - ((0 - integerRcvr) / integerArg); } else { result = (0 - integerRcvr) / (0 - integerArg); } } Isn't this relying on UB? like http://stackoverflow.com/questions/2539178/why-is-abs0x80000000-0x80000000 At worse, I would expect 0 - 0x8000000000000000LL to be converted to itself 0x8000000000000000LL... So can someone explain why this works? ((1 << 63) negated quo: 2) = (1 << 62) negated I guess it must be some compiler optimization, like: 0 - (0-a)/b -> 0 - (0/b-a/b) -> a/b But then, why doing the sign checks at all? Isn't it just result = integerRcvr / integerArg; whatever the signs? Maybe the compiler is able to just do that, but it sounds like obfuscation... Anyway, that won't work in primitiveDivLargeIntegers, i would expect: ((1 << 63) negated // -2) = (1 << 62) But I get ((1 << 63) negated // -2) = (1 << 62) negated Ah Ah, it looks like a bug this time, no Compiler optimization did save us We have several solutions... - let signed64BitValueOf: (1 << 63) negated fail - protect each and every negation of those - perform most arithmetic with unsigned, handle sign separately Nicolas

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Daily Commit Log
by commits＠source.squeak.org 28 Aug '12

28 Aug '12

Changes to Trunk (http://source.squeak.org/trunk.html) in the last 24 hours: http://lists.squeakfoundation.org/pipermail/packages/2012-August/005485.html Name: Monticello-cmm.522 Ancestors: Monticello-cmm.521 - Factor cut-and-pasted code. ============================================= http://lists.squeakfoundation.org/pipermail/packages/2012-August/005486.html Name: Collections-fbs.490 Ancestors: Collections-ul.488 Symbol >> #isBinary returns true if that Symbol is a valid binary message - something like #+, #>>=, and so on. It returns false for all other kinds of Symbols. ============================================= http://lists.squeakfoundation.org/pipermail/packages/2012-August/005487.html Name: CollectionsTests-fbs.191 Ancestors: CollectionsTests-ul.189 Symbol >> #isBinary returns true if that Symbol is a valid binary message - something like #+, #>>=, and so on. It returns false for all other kinds of Symbols. ============================================= http://lists.squeakfoundation.org/pipermail/packages/2012-August/005488.html Name: Tools-dtl.421 Ancestors: Tools-fbs.420 Initialize all ProcessBrowsers on image restart. Background: http://bugs.squeak.org/view.php?id=1578 fixed the case of open process browsers with auto-update running, for which the auto-update no longer worked after an image restart. However, an open process browser that does not have auto-update running also requires an initialize on image restart, otherwise a manual "update list" does not work. This is an old bug that had gone unnoticed. =============================================

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