May 2012 - Glasgow-haskell-users

Potential GSoC proposal: Reduce the speed gap between 'ghc -c' and 'ghc --make'
by Mikhail Glushenkov 24 May '12

24 May '12

Hi all, [Hoping it's not too late.] During my work on parallelising 'ghc --make' [1] I encountered a stumbling block: running 'ghc --make' can be often much faster than using separate compile ('ghc -c') and link stages, which means that any parallel build tool built on top of 'ghc -c' will be significantly handicapped [2]. As far as I understand, this is mainly due to the effects of interface file caching - 'ghc --make' only needs to parse and load them once. One potential improvement (suggested by Duncan Coutts [3]) is to produce whole-package interface files and load them in using mmap(). Questions: Would implementing this optimisation be a worthwhile/realistic GSoC project? What are other potential ways to bring 'ghc -c' performance up to par with 'ghc --make'? [1] https://github.com/23Skidoo/ghc-parmake [2] https://gist.github.com/1360470 [3] http://www.reddit.com/r/haskell/comments/qwj5j/the_cabal_of_my_dreams/c41a5… -- () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments

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How to staticly build ghc?
by Magicloud Magiclouds 21 May '12

21 May '12

Hi, I am with ghc 7.4.1. For some reason I need a totally static linked compilation to my code. But it failed when linking some packages came with ghc, like unix-2.5.1.0. Trying to rebuild ghc to make all staticly, but failed to find args like this when configuring ghc. What should I do? -- 竹密岂妨流水过山高哪阻野云飞 And for G+, please use magiclouds#gmail.com.

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ANNOUNCE: GHC 7.4.2 Release Candidate 1
by Ian Lynagh 18 May '12

18 May '12

We are pleased to announce the first release candidate for GHC 7.4.2: http://www.haskell.org/ghc/dist/7.4.2-rc1/ This includes the source tarball, installers for OS X and Windows, and bindists for amd64/Linux, i386/Linux, amd64/FreeBSD and i386/FreeBSD. Please test as much as possible; bugs are much cheaper if we find them before the release! Thanks Ian, on behalf of the GHC team

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Re: GHC 7.2.2 Distribution.Simple.Program.Ar
by Duncan Coutts 18 May '12

18 May '12

On 18 May 2012 22:03, Joe Buehler <aspam(a)cox.net> wrote: > Duncan Coutts wrote: > >> I'm very surprised it's not working on some version of Red Hat. This >> has worked on many varieties of linux for many years. You don't have >> some non-standard ar installed do you? What version of gnu binutils? >> (ar -V) > > No, it's the RHES ar program. > > # rpm -qf /usr/bin/ar > binutils-2.14.90.0.4-42 > > A CentOS 6 box works fine, so this may be a bug in RHES 3. > > The installed binutils is the latest for RHES 3. Locally compiled > versions of binutils have the same bug, so perhaps there is a bug > elsewhere in the system. For example, I do not have the very latest C > library. As a local workaround you can of course hack your Cabal library sources and reinstall the lib. Until we work out what's going on I'm a bit reluctant to chage the upstream version since that has been tested on so many systems (Linuxes, BSDs, other unixes). Duncan

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GHC 7.2.2 Distribution.Simple.Program.Ar
by Joe Buehler 18 May '12

18 May '12

I built GHC 7.2.2 on a LINUX box running RHEL 3. When compiling a package using this GHC it is trying to invoke ar thus: execve("/usr/bin/ar", ["/usr/bin/ar", "-r", "-c", "dist/build/libHSregex-base-0.93."..., "dist/build/Text/Regex/Base.o", "dist/build/Text/Regex/Base/Regex"..., "dist/build/Text/Regex/Base/Conte"..., "dist/build/Text/Regex/Base/Impl."...], [/* 45 vars */]) = 0 My version of ar does not like being invoked as "/usr/bin/ar -r -c lib.a file file file...", it complains that the .a file is missing. I believe it should be "/usr/bin/ar rc lib.a file file file...". This appears to originate in Distribution.Simple.Program.Ar. Can someone tell me what is going on here? Joe Buehler

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How to force recompilation of preprocessed files (-F -pgmF ..)
by Simon Hengel 17 May '12

17 May '12

Hi, I'm experimenting with a preprocessor to automatically generate test drivers[1]. The result depends on the existence of other files on the disk. When files are added or removed, the test driver has to be regenerated. Ideally ghc would just always recompile that single file (akin to make's .PHONY), and it should work with ghci's :reload and with cabal. I tried to touch the file within the preprocessor, but this does not work. It seems, that GHC checks the modification time only after preprocessing. Any ideas how to tackle this? Cheers, Simon [1] https://github.com/sol/hspec-discover

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Heads up: importing the Cabal issue tracker to github next week
by Bryan O'Sullivan 16 May '12

16 May '12

I am planning on doing this early next week, probably in two phases. As part of the import process, github will generate a *lot* of notification emails. I'm afraid there is nothing I can do to stem the tide, as github does not provide a mechanism to suppress these. If you have a github account, please brace yourself.

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[ANN] Accelerate version 0.12: GPU computing with Haskell
by Manuel M T Chakravarty 14 May '12

14 May '12

We just released version 0.12 of Data.Array.Accelerate, the GPGPU[1] library for Haskell: http://justtesting.org/gpu-accelerated-array-computations-in-haskell This is a beta release. The library is not perfect, but it is definitely usable, and we are looking for early adopters. Manuel [1] Currently only NVIDIA GPUs are supported via NVIDIA's CUDA framework.

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7.4.2 release plan update
by Ian Lynagh 13 May '12

13 May '12

Hi all, A quick 7.4.2 release plan update: We've been having trouble with our nightly builds, so we haven't managed to put out a release candidate yet. As soon as we have builds ready, we'll put the RC out, and all being well the release will follow one or two weeks later. Thanks Ian, on behalf of the GHC team

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Win64 support
by Bulat Ziganshin 09 May '12

09 May '12

Hello glasgow-haskell-users, the one thing that users of my program asked most is the Win64 support: http://code.google.com/p/freearc/issues/list . we have waited for a several years, but it's still not in GHC, so i want to know at least: why it's not going forward? can we have unregisterized build at least? -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

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