November 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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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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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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Status and future of the LLVM backend
by Ben Gamari 27 Dec '14

27 Dec '14

I've written down some thoughts on the current status and future direction of the LLVM backend here [1]. Have a look when you get a chance. To summarize, * it seems like LLVM 3.4 chokes on the code produced by my 3.5 rework when the `$def` symbols are marked as internal * ARM is broken (again) due to a bug in the GHC calling convention implementation; an LLVM fix is waiting to be merged * I have code reworking TNTC for LLVM 3.6; unfortunately LLVM 3.6 support will likely need to wait until 7.12 * Austin's LLVM packaging proposal seems very much like the right way forward * Anticipating this proposal, I have started collecting [2] optimization passes Cheers, - Ben [1]: http://smart-cactus.org/~ben/posts/2014-11-28-state-of-llvm-backend.html [2]: https://github.com/bgamari/ghc-llvm-analyses

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Failing tests: literals T5681 annotations
by Joachim Breitner 26 Dec '14

26 Dec '14

Hi, the CI weather is bad these days. Maybe a broken-window-effect? I currently observe Unexpected results from: TEST="literals T5681 annotations" Details: Compile failed (status 256) errors were: /tmp/ghc13786_0/ghc13786_5.s: Assembler messages: /tmp/ghc13786_0/ghc13786_5.s:26:0: Error: can't resolve `.rodata' {.rodata section} - `Main_zdwwork_info$def' {.text section} /tmp/ghc13786_0/ghc13786_5.s:46:0: Error: can't resolve `.rodata' {.rodata section} - `Main_work_info$def' {.text section} /tmp/ghc13786_0/ghc13786_5.s:66:0: Error: can't resolve `.rodata' {.rodata section} - `Main_main1_info$def' {.text section} /tmp/ghc13786_0/ghc13786_5.s:86:0: Error: can't resolve `.rodata' {.rodata section} - `Main_main_info$def' {.text section} /tmp/ghc13786_0/ghc13786_5.s:106:0: Error: can't resolve `.rodata' {.rodata section} - `Main_main2_info$def' {.text section} /tmp/ghc13786_0/ghc13786_5.s:126:0: Error: can't resolve `.rodata' {.rodata section} - `ZCMain_main_info$def' {.text section} *** unexpected failure for T5681(optllvm) =====> T8131(optllvm) 1496 of 4230 [0, 1, 0] Wrong exit code (expected 0 , actual 2 ) Stdout: Stderr: /usr/bin/ld: reopening annotations.o: No such file or directory /usr/bin/ld:annotations.o: bfd_stat failed: No such file or directory /usr/bin/ld: reopening annotations.o: No such file or directory /usr/bin/ld: BFD (GNU Binutils for Ubuntu) 2.22 internal error, aborting at ../../bfd/merge.c line 873 in _bfd_merged_section_offset /usr/bin/ld: Please report this bug. collect2: ld returned 1 exit status make[3]: *** [annotations] Error 1 *** unexpected failure for annotations(normal) Wrong exit code (expected 0 , actual 2 ) Stdout: Stderr: /usr/bin/ld: reopening literals.o: No such file or directory /usr/bin/ld:literals.o: bfd_stat failed: No such file or directory /usr/bin/ld: reopening literals.o: No such file or directory /usr/bin/ld: BFD (GNU Binutils for Ubuntu) 2.22 internal error, aborting at ../../bfd/merge.c line 873 in _bfd_merged_section_offset /usr/bin/ld: Please report this bug. collect2: ld returned 1 exit status make[3]: *** [literals] Error 1 *** unexpected failure for literals(normal) Does anyone feel responsible? 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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Status updates
by Austin Seipp 18 Dec '14

18 Dec '14

Hi *, Here are some status updates: - I've merged the Applicative Monad patchset! Yay! Many thanks to Nathan Howell for helping me out in the end there. Please let me know if anything explodes horribly (I hope not). - Gabor has set up some build documentation for us based on HEAD, hooray! See here - http://haskell.inf.elte.hu/ - I still need to fix haskell.org/ghc to link to this properly (there may be other dead links, please let me know). - As I'm sure most of you were aware, it was a slow week due to ICFP & related events being most of last week. - As I'm also sure you were aware, Haskell.org suffered a lot of instability this past week. I've been focusing most of my efforts since about Thursday on this, since it's come and gone a lot and has needed some consistent monitoring. Unfortunately, it is not done yet, and there is still more work to be done. :( - ghc.haskell.org was migrated to a new server in the US as a part of this effort this weekend (send a thanks to Herbert). In general, you should notice nothing really new, but latency for UK citizens may be a bit higher than it was before now. - Now that Applicative/Monad is done, there are some more changes to 'base' that will happen (Bifunctors, Foldable/Traversable) that will need to happen. So I'm sure this discussion will start soon. - I still can't set up the Windows bot yet, sorry! Phabricator work is still not yet available upstream. Hopefully soon. - Sergei spent some time filing bugs that we should fix in the testsuite, because they fail --slow validate. I believe these are two of them: - https://ghc.haskell.org/trac/ghc/ticket/9567 - https://ghc.haskell.org/trac/ghc/ticket/9566 We'll probably need to fix these before we turn it on. Simon, these look like something up your alley... - For those who missed ICFP, Simon gave a nice status update for GHC, which is on YouTube: https://www.youtube.com/watch?v=Ex79K4lvJno&list=PL4UWOFngo5DW6nKDjK0UB5Oy9… -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

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Trouble committing
by Andreas Voellmy 14 Dec '14

14 Dec '14

Hi GHCers, I just fixed a bug (#9423) and went through the Phab workflow. Then I did a fresh checkout from git and ran: $ git checkout master $ arc patch --nobranch D129 $ git push origin master as explained on https://ghc.haskell.org/trac/ghc/wiki/Phabricator, but on the last command I get this error: fatal: remote error: access denied or repository not exported: /ghc.git Maybe I just no longer have commit access to ghc? If so, could someone restore my access? Or I'd be happy if someone else can push the patch. Thanks, Andi

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