December 2014 - ghc-devs

arc land changes author
by Joachim Breitner 19 Dec '15

19 Dec '15

Hi, I was just about to apply a DR by David. First I ran $ arc patch D390 which put me on a feature branch. Then I reworded the commit with $ git commit --amend and then I tried to land it with $ arc land Luckily I also passed --hold... It even asked me if I want to land the commit although I am not the author: This branch has revision 'D390: Reorder GHC.List; fix performance regressions' but you are not the author. Land this revision by dfeuer? [y/N] y But it still put me in the author field: $ git show HEAD commit a387c359b99667ce55016de3816b5d9873a155db Author: Joachim Breitner <mail(a)joachim-breitner.de> Date: Wed Oct 29 08:17:05 2014 +0100 Reorder GHC.List; fix performance regressions Summary: Rearrange some oddly placed code. (and undid my commit message changes....) Did I do something wrong? Anyways, it said something along the lines of Cleaning up feature branch... (Use `git checkout -b 'arcpatch-D390' 'a3ceb0e7f44d53f728fb8bd0dfb4c97297818029'` if you want it back.) so with $ git commit --amend -C a3ceb0e7f44d53f728fb8bd0dfb4c97297818029 I was able to get the edited commit message with the right author back. Greetings, Joachim -- Joachim “nomeata” Breitner mail(a)joachim-breitner.de • http://www.joachim-breitner.de/ Jabber: nomeata(a)joachim-breitner.de • GPG-Key: 0xF0FBF51F Debian Developer: nomeata(a)debian.org

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Right way to turn off dynamic linking in build.mk
by Johan Tibell 07 Jul '15

07 Jul '15

Some times when I play around with GHC I'd like to turn off dynamic linking to make GHC compile faster. I'm not sure what the right way to do this in build.mk. It's made confusing by the conditional statements in that file: GhcLibWays = $(if $(filter $(DYNAMIC_GHC_PROGRAMS),YES),v dyn,v) This line make me worry that if I don't put DYNAMIC_GHC_PROGRAMS = NO in the right place in build.mk it wont "take". There's also this one: ifeq "$(PlatformSupportsSharedLibs)" "YES" GhcLibWays += dyn endif Seeing this makes me wonder if DYNAMIC_GHC_PROGRAMS = NO DYNAMIC_BY_DEFAULT = NO is enough or if the build system still sniffs out the fact that my platform supports dynamic linking. Could someone please give an authoritative answer to how to turn off dynamic linking? -- Johan

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Automating GHC build for Windows
by Roman Kuznetsov 29 Mar '15

29 Mar '15

Hello *, As I am still new in this, I will ask. Were there any attempt to automate GHC build process on Windows with some kind of CI engine, like Hudson, Jenkins, etc.? It seems to be rather helpful to publish build results if not after each commit, but at least once every day. WDYT? -- Sincerely yours, Roman Kuznetsov

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Porting to Haiku
by Jessica Hamilton 11 Mar '15

11 Mar '15

Hi, I (and one other) am working on porting GHC to Haiku; we've successfully got a working GHC cross-compiler running on Haiku, and now are able to also build GHC on Haiku from the cross-compiler when using the "quickest" profile in the mk/build.mk file. However, using the default build profile, we're running into a couple of issues. 1. A random segfault in ghc-stage1 (is probably an issue in Haiku, not entirely sure yet), with the following call stack: runCFinalizers + 0x3a runAllCFinalizers + 0x37 hs_exit_ +0x99 shutdownHaskellAndExit + 0x2f hs_main + 0xb1 .../ghc-7.8.3/inplace/lib/bin/ghc-stage1 + 0xc7b374 _start + 0x4b runtime_loader + 0x130 I can't really see anything obvious in the source code myself (although our debugger fails to enumerate the semaphores, and also needs to be killed). Restarting the build is sufficient to get past the issue, however. 2. A more pressing issue is with ghc-cabal. It fails with the error "resource exhausted" when running the following command: inplace/bin/ghc-cabal copy compiler stage2 This error is reproducible every time. I've tried setting up a profile build in the mk/build.mk file in order to get a stack trace from ghc-cabal; however, after rebuilding GHC from scratch, running ghc-cabal +RTS -xc, it still complains that the flag -xc requires the program to be built with -prof. Some advice would be handy before diving into another couple hours of rebuilding GHC to try and get a profiled build of ghc-cabal out of the build system ;-) Cheers, Jessica

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Can't install packages with my inplace compiler
by Simon Peyton Jones 06 Feb '15

06 Feb '15

When I say cabal install --with-ghc=/home/simonpj/5builds/HEAD-2/inplace/bin/ghc-stage2 I get this ghc-stage2: ghc no longer supports single-file style package databases (dist/package.conf.inplace) use 'ghc-pkg init' to create the database with the correct format. Now, this is an old build tree, and I could blow it away entirely, but maybe there is something else going on. What should I do? Thanks (all on Linux) Simon

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RE: cminusminus.org does not have a link to the spec
by Simon Peyton Jones 19 Jan '15

19 Jan '15

Sergei C-- was originally envisaged as a target language for a variety of compilers. But in fact LLVM, which was developed at a similar time, "won" that race and has built a far larger ecosystem. That's fine with us -- it's great how successful LLVM has been -- but it means that C-- is now used essentially only in GHC. I'm not sure where the original C-- documents now are; Norman can you say? (I do know that the cminusminus.org has lapsed.) The GHC variant of C-- is defined mainly by the Cmm data type in GHC's source code. It does have a concrete syntax, because some bits of GHC's runtime system are written in Cmm. But I fear that this concrete language is not well documented. (Simon Marlow may know more here.) Because GHC's Cmm is part of GHC, we are free to change it. Would you like to say more about the change you want to make, and why you want to make it? Is this relating directly to GHC or to some other project? Simon | -----Original Message----- | From: Sergei Trofimovich [mailto:slyich@gmail.com] | Sent: 14 September 2014 17:16 | To: Simon Peyton Jones | Subject: cminusminus.org does not have a link to the spec | | Hello Simon! | | I had a plan to tweak a bit "import" statement | syntax of Cmm in GHC. | | Namely, to distinct between | import some_c_function; | import some_c_global_variable; | | To try it I first attempted to find latest c-- spec | (to find some design sketches if available) at | | http://www.cminusminus.org/c-downloads/ | | But seems the links (and images?) have gone away | as well as rsync server described at: | | http://www.cminusminus.org/the-c-rsync-server/ | | Maybe you could forward it to site admins so they would | tweak links or point me to working copy. | | Apologies for bothering you on such minor | | Thank you! | | -- | | Sergei

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Out of memory mystery
by Lennart Augustsson 19 Jan '15

19 Jan '15

I'm running the 32-bit Windows version of ghc-7.8.3. Here are two runs: $ RunMu +RTS -A64M -h -Sstat.log -i1 -RTS -c Strat.App.Abacus.Main Compiling afresh Strat.App.Abacus.Main Compiled afresh Strat.App.Abacus.Main, 1302.84s $ RunMu +RTS -A64M -Sstat.log -i1 -RTS -c Strat.App.Abacus.Main Compiling afresh Strat.App.Abacus.Main RunMu.exe: out of memory The binary is compiled without profiling, but in the first run I'm using the -h flag to get the rudimentary heap profile. And with -h it works, but without the flag it runs out of memory. Any bright ideas from the RTS experts on why this could happen? -- Lennart

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ANNOUNCE: GHC 7.10.1 Release Candidate 1
by Austin Seipp 17 Jan '15

17 Jan '15

We are pleased to announce the first release candidate for GHC 7.10.1: https://downloads.haskell.org/~ghc/7.10.1-rc1/ This includes the source tarball and bindists for 64bit/32bit Linux and Windows. Binary builds for other platforms will be available shortly. (CentOS 6.5 binaries are not available at this time like they were for 7.8.x). These binaries and tarballs have an accompanying SHA256SUMS file signed by my GPG key id (0x3B58D86F). We plan to make the 7.10.1 release sometime in February of 2015. We expect another RC to occur during January of 2015. Please test as much as possible; bugs are much cheaper if we find them before the release! -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

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ANNOUNCE: GHC version 7.8.4
by Austin Seipp 12 Jan '15

12 Jan '15

============================================================== The (Interactive) Glasgow Haskell Compiler -- version 7.8.4 ============================================================== The GHC Team is pleased to announce a new patchlevel release of GHC, 7.8.4. This is an important bugfix release relative to 7.8.3 (with over 30 defects fixed), so we highly recommend upgrading from the previous 7.8 releases. The full release notes are here: https://downloads.haskell.org/~ghc/7.8.4/docs/html/users_guide/release-7-8-… How to get it ~~~~~~~~~~~~~ The easy way is to go to the web page, which should be self-explanatory: https://www.haskell.org/ghc/ We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place. Packages will appear as they are built - if the package for your system isn't available yet, please try again later. Background ~~~~~~~~~~ Haskell is a standard lazy functional programming language. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, whatever). GHC is distributed under a BSD-style open source license. A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page (see below). On-line GHC-related resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ GHC developers' home page http://ghc.haskell.org/trac/ghc/ Haskell home page http://www.haskell.org/ Supported Platforms ~~~~~~~~~~~~~~~~~~~ The list of platforms we support, and the people responsible for them, is here: http://ghc.haskell.org/trac/ghc/wiki/Platforms http://ghc.haskell.org/trac/ghc/wiki/CodeOwners Ports to other platforms are possible with varying degrees of difficulty. The Building Guide describes how to go about porting to a new platform: http://ghc.haskell.org/trac/ghc/wiki/Building Developers ~~~~~~~~~~ We welcome new contributors. Instructions on accessing our source code repository, and getting started with hacking on GHC, are available from the GHC's developer's site run by Trac: http://ghc.haskell.org/trac/ghc/ Mailing lists ~~~~~~~~~~~~~ We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at http://www.haskell.org/mailman/listinfo/glasgow-haskell-users http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see http://www.haskell.org/mailman/listinfo/ Some GHC developers hang out on #haskell on IRC, too: http://www.haskell.org/haskellwiki/IRC_channel Please report bugs using our bug tracking system. Instructions on reporting bugs can be found here: http://www.haskell.org/ghc/reportabug Hashes & Signatures ~~~~~~~~~~~~~~~~~ On https://downloads.haskell.org/~ghc/7.8.4/ you will find a signed copy of the SHA256 hashes for the tarballs, using my GPG key (keyid 0x3B58D86F). -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

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linker_unload
by Simon Peyton Jones 08 Jan '15

08 Jan '15

I'm getting this for test linker_unload on Linux. I'm sure it's not my fault! But it makes validate fail Simon Wrong exit code (expected 0 , actual 2 ) Stdout: Stderr: linker_unload: /5playpen/simonpj/HEAD-2/libraries/integer-gmp2/dist-install/build/libHSinteg_2MbWUstH60IEgCAexOk3v3.a: unknown symbol `__gmpn_rshift' linker_unload: resolveObjs failed make[3]: *** [linker_unload] Error 1 *** unexpected failure for linker_unload(normal)

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