- ghc-devs - Haskell.org

Consistent CI failure in job nightly-i386-linux-deb9-validate
by Bryan Richter 29 Sep '22

29 Sep '22

Hi all, For the past week or so, nightly-i386-linux-deb9-validate has been failing consistently. They show up on the failure dashboard because the logs contain the phrase "Cannot allocate memory". I haven't looked yet to see if they always fail in the same place, but I'll do that soon. The first example I looked at, however, has the line "xz: (stdin): Cannot allocate memory", so it's not GHC (alone) causing the problem. As a consequence of showing up on the dashboard, the jobs get restarted. Since they fail consistently, they keep getting restarted. Since the jobs keep getting restarted, the pipelines stay alive. When I checked just now, there were 8 nightly runs still running. :) Thus I'm going to cancel the still-running nightly-i386-linux-deb9-validate jobs and let the pipelines die in peace. You can still find all examples of failed jobs on the dashboard: https://grafana.gitlab.haskell.org/d/167r9v6nk/ci-spurious-failures?orgId=2… To prevent future problems, it would be good if someone could help me look into this. Otherwise I'll just disable the job. :(

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Pushing to nofib
by Simon Peyton Jones 27 Sep '22

27 Sep '22

Friends How do I push to the nofib/ repository? I just wanted to add some documentation. I'm on branch 'master' and tried to push. Got this below. What next? Thanks Simon bash$ git push Enumerating objects: 5, done. Counting objects: 100% (5/5), done. Delta compression using up to 24 threads Compressing objects: 100% (3/3), done. Writing objects: 100% (3/3), 543 bytes | 543.00 KiB/s, done. Total 3 (delta 2), reused 0 (delta 0) remote: GitLab: You are not allowed to push code to protected branches on this project. To gitlab.haskell.org:ghc/nofib.git ! [remote rejected] master -> master (pre-receive hook declined) error: failed to push some refs to 'git@gitlab.haskell.org:ghc/nofib.git' simonpj@LHR-WD-22561:~/code/HEAD-1/nofib$

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GItlab search
by Simon Peyton Jones 26 Sep '22

26 Sep '22

Friends I'm struggling with GitLab search. eg I was looking for #22200 I wen to https://gitlab.haskell.org/ghc/ghc/-/issues, and put "-DEEBUG" and "slow" in the search box. No #22200. Yet both of those strings appear in the title of the ticket. Looking for DEBUG or *DEBUG also fails. I find that DDEBUG succeeds. What are the rules? Thanks Simon

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Tier 1 architectures
by Simon Peyton Jones 22 Sep '22

22 Sep '22

Ben, Matthew, Moritz, and friends Is this wiki page about architectures still accurate? https://gitlab.haskell.org/ghc/ghc/-/wikis/platforms For example, ARM is not Tier 1, or "apple silicon". Yet I know some of our developers have invested lots of effort in other architectures, so maybe those efforts are not reflected here. Relevant is Moritz's post about 32-bit architectures <https://discourse.haskell.org/t/running-project-built-on-raspberry-pi-with-…> . We should in due course add Javascript and Web Assembly as Tier 1 back ends? Are we saying "if your customer bases uses Tier 2 architectures, you can't rely on GHC from one release to the next"? I wonder if there are companies for which Tier-2 architectures are mission-critical. Mis-aligned expectations cause upset. I mention all this because it is relevant to our stability guarantees. Every time we release we should point to this list. Simon

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Alternative to isTypeLevPoly
by Csaba Hruska 16 Sep '22

16 Sep '22

Hello GHC Devs, I've noticed that the `isTypeLevPoly` function has been removed from GHC since 9.4. I used it to decide the validity of querying the representation type of every value in the STG IR. It was mandatory to prevent GHC panics, because there are a lot of partial functions in GHC. Is there an alternative to `isTypeLevPoly` in GHC 9.4? Best regards, Csaba Hruska

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Haskell program coverage
by Simon Peyton Jones 15 Sep '22

15 Sep '22

Matthias, David, David Binder <http://ps.informatik.uni-tuebingen.de/team/binder/>apparently has some PRs for GHC's HPC program coverage stuff that have somehow languished un-merged for some time. David, can you point us to them, so we can look? Matthias <https://github.com/Tritlo>wants to extend HPC in a number of ways. See here <https://github.mpg.is/posts/2022/04/26/better-hpc-traces.html>and here <https://github.com/ghc-proposals/ghc-proposals/pull/539>. Maybe you want to talk to each other? You are both here at ICFP! And it would be great to have a little team that cared about HPC more generally, and could look after it. Thanks. Apologies if I have misunderstood anyone. Simon

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Runtime linker
by Lana Black 13 Sep '22

13 Sep '22

Hello, My personal project involves making a port of GHC for an almost bare-bones environment, which doesn't provide runtime linking support. GHC configure script sets `TargetHasRTSLinker` flag, but it seems to be ignored in RTS itself, and the linker is built regardless. Is this a regression, perhaps due to the migration from Makefiles to Hadrian? Or is building RTS without runtime linker no longer supported? Thank you.

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GHC compiler perf CI
by Simon Peyton Jones 11 Sep '22

11 Sep '22

Dear devs I used to use the build *x86_64-linux-deb10-int_native-validate* as the place to look for compiler/bytes-allocated changes in perf/compiler. But now it doesn't show those results any more, only runtime/bytes-allocated in perf/should_run. - Should we not run perf/compiler in every build? - Why has it gone from the build above - Which build should I look at to see perf/compiler data Thanks Simon

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When do we get loads/stores with volatile semantics (if we get them at all)?
by Travis Whitaker 09 Sep '22

09 Sep '22

Hello Haskell Friends, Recently I noticed some strange behavior in a program that uses peek/poke to manipulate memory mapped hardware registers, that smells a lot like missing volatile semantics to me. It hadn’t occurred to me that peek/poke might not have volatile semantics (they return an IO, and that IO has to happen, right?), but naturally once they’re lowered all such bets are off. This made me wonder: - Do we have a type like #Addr whose loads/stores have volatile semantics? - Do we have any primops with volatile semantics at all? - Are there any tricks one could use to get volatile semantics out of base’s peek/poke functions? Poking around, I’m afraid the answer to all three of these is “no.” If so, I’d be very interested in contributing volatile load/store primops and working out some way to make them easily available from Foreign.Storable. Does no such thing currently exist or am I missing something? Thanks for all your ongoing efforts, Travis

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Unix library apparently broken
by Simon Peyton Jones 07 Sep '22

07 Sep '22

My !8750 builds are failing in the Unix library with the "pattern match is redundant" message below. And indeed the pattern match is redundant. Here's the .hs version of the file unpackRLimit :: CRLim -> ResourceLimit unpackRLimit (18446744073709551615) = ResourceLimitInfinity {-# LINE 101 "libraries/unix/System/Posix/Resource.hsc" #-} unpackRLimit other {-# LINE 103 "libraries/unix/System/Posix/Resource.hsc" #-} | ((18446744073709551615) :: CRLim) /= (18446744073709551615) && {-# LINE 104 "libraries/unix/System/Posix/Resource.hsc" #-} other == (18446744073709551615) = ResourceLimitUnknown {-# LINE 105 "libraries/unix/System/Posix/Resource.hsc" #-} {-# LINE 106 "libraries/unix/System/Posix/Resource.hsc" #-} {-# LINE 107 "libraries/unix/System/Posix/Resource.hsc" #-} | ((18446744073709551615) :: CRLim) /= (18446744073709551615) && {-# LINE 108 "libraries/unix/System/Posix/Resource.hsc" #-} other == (18446744073709551615) = ResourceLimitUnknown {-# LINE 109 "libraries/unix/System/Posix/Resource.hsc" #-} {-# LINE 110 "libraries/unix/System/Posix/Resource.hsc" #-} | otherwise = ResourceLimit (fromIntegral other) The red line means that the blue lines will fail. So the warning looks correct. But it's stopping my CI from working. I have no idea why this doesn't happen in HEAD. Can anyone help? Thanks Simon Command line: _build/stage0/bin/aarch64-linux-gnu-ghc -Wall -Wcompat -fdiagnostics-color=never -dynamic-too -hisuf hi -osuf o -hcsuf hc -static -hide-all-packages -no-user-package-db '-package-env -' '-package-db _build/stage1/lib/package.conf.d' '-this-unit-id unix-2.7.2.2' '-package-id base-4.17.0.0' '-package-id bytestring-0.11.3.1' '-package-id time-1.12.2' -i -i/builds/ghc/ghc/_build/stage1/libraries/unix/build -i/builds/ghc/ghc/_build/stage1/libraries/unix/build/autogen -i/builds/ghc/ghc/libraries/unix -Irts/include -I_build/stage1/libraries/unix/build -I_build/stage1/libraries/unix/build/include -Ilibraries/unix/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/time-1.12.2/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/bytestring-0.11.3.1/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/base-4.17.0.0/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/ghc-bignum-1.3/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/rts-1.0.2/include -optP-include -optP_build/stage1/libraries/unix/build/autogen/cabal_macros.h -outputdir _build/stage1/libraries/unix/build -Wnoncanonical-monad-instances -optc-Wno-error=inline -optP-Wno-nonportable-include-path -c _build/stage1/libraries/unix/build/System/Posix/Resource.hs -o _build/stage1/libraries/unix/build/System/Posix/Resource.o -fllvm-fill-undef-with-garbage -dno-debug-output -Wall -XHaskell2010 -no-global-package-db -package-db=/builds/ghc/ghc/_build/stage1/lib/package.conf.d -ghcversion-file=rts/include/ghcversion.h -ghcversion-file=rts/include/ghcversion.h -O -Wno-deprecated-flags -Werror -dlint ===> Command failed with error code: 1 libraries/unix/System/Posix/Resource.hsc:107:7: error: [-Woverlapping-patterns, -Werror=overlapping-patterns] Pattern match is redundant In an equation for ‘unpackRLimit’: unpackRLimit other | ((18446744073709551615) :: CRLim) /= (18446744073709551615) && other == (18446744073709551615) = ... | 107 | | ((#const RLIM_SAVED_CUR) :: CRLim) /= (#const RLIM_INFINITY) && | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...

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