- ghc-devs - Haskell.org

RTS linker refactoring
by Sylvain Henry 08 Dec '15

08 Dec '15

Hi devs, I have made a patch to refactor the RTS linker, especially to drastically reduce its memory usage: https://phabricator.haskell.org/D1470 We need to test it on differrent OS/architectures before it can be merged. Here is the current state: - Linux/x86-64: OK (Harbormaster and I) - Solaris/x86-64: was OK, maybe needs to be retested (@kgardas) - OpenBSD/x86-64: was OK, maybe needs to be tetested (@kgardas) - Solaris/i386: was failing with unrelated error, needs to be retested (@kgardas) - Linux/PowerPC: OK (@erikd) - Linux/ARM: was failing with unrelated #11123 (@erikd), OK? (@bgamari) - Windows: ? - MacOS: ? - ia64: ? I don't have access to Windows and Mac OS boxes so I don't even know if it compiles there. Could someone test it (validate) on these OSes and report any issue they encounter to me (by mail or on phabricator)? Do we support ia64 architecture? Thanks! Sylvain

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Re: [GHC] #11177: panic! tc_hs_type: record
by Alan & Kim Zimmerman 08 Dec '15

08 Dec '15

I am travelling until Thursday, will only be able to look on Friday. Alan On 08 Dec 2015 2:44 PM, "GHC" <ghc-devs(a)haskell.org> wrote: > #11177: panic! tc_hs_type: record > ---------------------------------+----------------------------- > Reporter: apanagio | Owner: > Type: bug | Status: new > Priority: normal | Milestone: > Component: Compiler | Version: 7.6.3 > Resolution: | Keywords: > Operating System: Linux | Architecture: x86 > Type of failure: None/Unknown | Test Case: > Blocked By: | Blocking: > Related Tickets: | Differential Rev(s): > Wiki Page: | > ---------------------------------+----------------------------- > Changes (by simonpj): > > * cc: alanz (added) > > > Comment: > > This looks like fallout from the 'refactor `ConDecl` patch. > > Alan? > > Simon > > -- > Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11177#comment:1> > GHC <http://www.haskell.org/ghc/> > The Glasgow Haskell Compiler >

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A GHC Library
by Richard Eisenberg 08 Dec '15

08 Dec '15

Hi devs, It has struck me that we have a vast trove of documentation about GHC in the form of academic papers, but little organization to this trove. The papers are scattered across authors' websites, and sometimes it is hard to remember what a paper is titled when searching for it. I have thus started a wiki page here: https://ghc.haskell.org/trac/ghc/wiki/Library I would love for this page to be the Definitive List of GHC-related papers. The list I've included is, of course, woefully short, but it is a starting point. Please add to it! Have you written a GHC paper? If so, make sure it's included. Thanks, Richard

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Kind equalities
by Simon Peyton Jones 07 Dec '15

07 Dec '15

Richard What’s your ETA on the kind-equality stuff? We wondered in today’s call. We want to make an RC next week. Simon

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[ANNOUNCE] 7.10.3 release candidate 2
by Ben Gamari 07 Dec '15

07 Dec '15

Hello everyone, We are pleased to announce the second release candidate for GHC 7.10.3: https://downloads.haskell.org/~ghc/7.10.3-rc2/ This release differs from -rc1 by only two commits, * Disable the newly-introduced readelf configure check on non-ELF platforms. * Remove some tracing output from the typechecker that was causing some testsuites to fail. At the moment you should find the source tarball as well as 32- and 64-bit modern Linux (built on Debian 8) binary distributions available at the above URL. Windows and CentOS binaries will be made available shortly. As usual, you may need to work around our content delivery network's update latency by adding redundant forward-slashes to the URL. As far as OS X support goes, we are still looking for contributors to help us to support their platform by offering access to hardware, testing, or builds. Please let us know if you would be willing to provide any of the above. Happy testing! Cheers, - Ben

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How do I use CallStack?
by Richard Eisenberg 07 Dec '15

07 Dec '15

Hi devs, I wish to use the new CallStack feature to track call sites of a function. I want my function to print out where it was called from. I do not want to call `error`. How do I do this? I looked in the release notes. They describe the CallStack feature at an overview, and the docs suggest that it has a Show instance. But the notes don't say where to import CallStack from. I found it in GHC.Stack, but I'm unsure this is the right place to take it from. The GHC release notes also refer me to the ghc-prim release notes. These (which I assume are ghc-prim/changelog.md) don't discuss CallStack. In any case, when I try to `show ?callstack`, I learn that CallStack is not an instance of Show, or I somehow haven't imported the instance. Help? Thanks! Richard

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Haddock for GHC 8.0
by Ben Gamari 07 Dec '15

07 Dec '15

tl;dr: Help needed to bring Haddock up-to-date for the GHC 8.0 release. Hello everyone, As you likely know, the GHC 8.0 release cycle is quickly drawing to a close. One of the tasks that remains outstanding is porting the patches on Haddock's `ghc-head` branch to `master`. This task is bound to require a bit more work than usual this time around as both GHC and Haddock have evolved significantly (which is a good thing!). Sadly, Austin and I are quite busy at the moment and would be hard-pressed to undertake such a task ourselves. Consequently, we need a volunteer to pick up this work. At the moment the GHC release schedule is largely determined by progress on the no-kinds branch but we expect to have a release candidate out within the next two weeks. If we aren't able to find someone to bring haddock up-to-date by mid-January I'm afraid we'll have to release GHC 8.0 with the current state of the `ghc-head` branch. Considering the significant effort that went into this summer's GSoC projects, this would be a shame. If you think you might be able to contribute to this effort, please say so in this thread. Thanks for all of your effort, - Ben

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Phab out of memory
by Richard Eisenberg 07 Dec '15

07 Dec '15

I just tried to update D808, but the following happened. Any ideas? Thanks, Richard rae:22:44:22 ~/Documents/ghc> arc diff origin/master --update D808 --allow-untracked --head HEAD --trace libphutil loaded from '/Users/rae/local/share/libphutil/src'. arcanist loaded from '/Users/rae/local/share/arcanist/src'. Config: Reading user configuration file "/Users/rae/.arcrc"... Config: Did not find system configuration at "/etc/arcconfig". Working Copy: Reading .arcconfig from "/Users/rae/Documents/ghc/.arcconfig". Working Copy: Path "/Users/rae/Documents/ghc" is part of `git` working copy "/Users/rae/Documents/ghc". Working Copy: Project root is at "/Users/rae/Documents/ghc". Config: Did not find local configuration at "/Users/rae/Documents/ghc/.git/arc/config". Loading phutil library from '/Users/rae/Documents/ghc/.arc-linters/arcanist-external-json-linter'... >>> [0] <conduit> conduit.connect() <bytes = 545> >>> [1] <http> https://phabricator.haskell.org/api/conduit.connect <<< [1] <http> 172,210 us <<< [0] <conduit> 1,237,507 us >>> [2] <event> diff.didCollectChanges <listeners = 0> <<< [2] <event> 138 us >>> [3] <conduit> differential.query() <bytes = 189> >>> [4] <http> https://phabricator.haskell.org/api/differential.query <<< [4] <http> 134,230 us <<< [3] <conduit> 134,659 us >>> [5] <conduit> differential.getcommitmessage() <bytes = 212> >>> [6] <http> https://phabricator.haskell.org/api/differential.getcommitmessage <<< [6] <http> 109,179 us <<< [5] <conduit> 109,721 us >>> [7] <conduit> differential.parsecommitmessage() <bytes = 1,358> >>> [8] <http> https://phabricator.haskell.org/api/differential.parsecommitmessage <<< [8] <http> 106,739 us <<< [7] <conduit> 107,306 us >>> [9] <event> diff.didBuildMessage <listeners = 0> <<< [9] <event> 168 us >>> [10] <exec> $ git rev-parse --git-dir <<< [10] <exec> 8,502 us >>> [11] <exec> $ git rev-parse 'HEAD' <<< [11] <exec> 5,632 us >>> [12] <exec> $ git merge-base 'origin/master' '9eb7237750f9409a4e1b00c509f2519983d97130' <<< [12] <exec> 119,778 us >>> [13] <exec> $ git log --first-parent --format=medium 'c865c425a37b0bc52f4dead9d70eb0ee2bc287d6'..'9eb7237750f9409a4e1b00c509f2519983d97130' <<< [13] <exec> 117,008 us >>> [14] <conduit> differential.querydiffs() <bytes = 191> >>> [15] <http> https://phabricator.haskell.org/api/differential.querydiffs <<< [15] <http> 3,462,000 us <<< [14] <conduit> 3,462,526 us [2015-12-05 03:44:31] EXCEPTION: (HTTPFutureHTTPResponseStatus) [HTTP/500] Internal Server Error >>> UNRECOVERABLE FATAL ERROR <<< Out of memory (allocated 501743616) (tried to allocate 70083487 bytes) /opt/phabricator/src/aphront/response/AphrontResponse.php:167 ┻━┻ ︵ ¯\_(ツ)_/¯ ︵ ┻━┻ at [<phutil>/src/future/http/BaseHTTPFuture.php:339] arcanist(head=master, ref.master=87306cfe1453), external-json-linter(), phutil(head=master, ref.master=e65ffd33db02) #0 BaseHTTPFuture::parseRawHTTPResponse(string) called at [<phutil>/src/future/http/HTTPSFuture.php:415] #1 HTTPSFuture::isReady() called at [<phutil>/src/future/Future.php:37] #2 Future::resolve(NULL) called at [<phutil>/src/future/FutureProxy.php:34] #3 FutureProxy::resolve() called at [<phutil>/src/conduit/ConduitClient.php:58] #4 ConduitClient::callMethodSynchronous(string, array) called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:2231] #5 ArcanistDiffWorkflow::loadActiveLocalCommitInfo() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:2129] #6 ArcanistDiffWorkflow::getGitUpdateMessage() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:2095] #7 ArcanistDiffWorkflow::getDefaultUpdateMessage() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:1882] #8 ArcanistDiffWorkflow::getUpdateMessage(array, NULL) called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:763] #9 ArcanistDiffWorkflow::buildRevisionFromCommitMessage(ArcanistDifferentialCommitMessage) called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:469] #10 ArcanistDiffWorkflow::run() called at [<arcanist>/scripts/arcanist.php:382]

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Re: ambiguous type stuff
by David Feuer 06 Dec '15

06 Dec '15

I think I didn't explain myself well enough. I'm not talking about expanded defaulting, although that may be tied up with the same mechanisms. Perhaps the best thing is just to work on the error message text for certain ambiguous type situations. Notably, situations where adding a proxy argument or similar is needed to avoid the error tend to be pretty mysterious until you realize that the system is not complaining because it can't determine a type, but rather because there is no way to pinpoint that type at the use site. If F is a type family then f :: Foo x => F x has a perfectly sensible translation, namely f :: forall x . Foo x -> F x The problem is purely one of inference on the Haskell side: there is no way to add a signature *at the call site* that determines what value of x to pass to f. The error message about x being ambiguous because F is a type family has to be read a bit backwards. At a *use site*, it'll be pretty clear-cut what's ambiguous, and it will soon become clear why it can't be pinned down. Perhaps it would pay to change the error message to explain why the type signature renders the term unusable.

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Plugins: How to determine ghc vs ghci
by Levent Erkok 05 Dec '15

05 Dec '15

I'm working on a plugin, and would like to be able to tell if it's GHC or GHCi that's running. I tried: df <- getDynFlags let isGHCi = ghcMode df == CompManager Alas, while that correctly tells apart "ghci" from "ghc -c", it also returns True when ghc is called without the "-c" argument. Is there a better/more robust way of figuring out whether we're in an interactive session? -Levent.

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