December 2016 - ghc-devs

How to inline early in a GHC plugin?
by Conal Elliott 08 Dec '16

08 Dec '16

I'm implementing a GHC plugin that installs a `BuiltInRule` that does the work, and I'd like to learn how to inline more flexibly. Given an identifier `v`, I'm using `maybeUnfoldingTemplate (realIdUnfolding v)` to get a `Maybe CoreExpr`. Sometimes this recipe yields `Nothing` until a later compiler phase. Meanwhile, I guess my variable `v` has been replaced by one with inlining info. First, am I understanding this mechanism correctly? A GHC source pointer to how inlining is made available would help me. Second, can I access the inlining info before it's made available to the rest of the simplifier? Thanks, - Conal

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Measuring performance of GHC
by Michal Terepeta 08 Dec '16

08 Dec '16

Hi everyone, I've been running nofib a few times recently to see the effect of some changes on compile time (not the runtime of the compiled program). And I've started wondering how representative nofib is when it comes to measuring compile time and compiler allocations? It seems that most of the nofib programs compile really quickly... Is there some collections of modules/libraries/applications that were put together with the purpose of benchmarking GHC itself and I just haven't seen/found it? If not, maybe we should create something? IMHO it sounds reasonable to have separate benchmarks for: - Performance of GHC itself. - Performance of the code generated by GHC. Thanks, Michal

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timings for individual compiler passes (in rc3)
by Johannes Waldmann 07 Dec '16

07 Dec '16

Hi. There is this (closed) https://ghc.haskell.org/trac/ghc/ticket/11653 and it's landed in 8.rc3. Thats good, and I want to make an effort to use this. But how? Just "-v2"? This gives a lot of noise. And no summary? Automatic analysis (of the output text stream, by external program) could be somewhat easier if each data set (starting at "\n!!!") did occupy exactly one line (currently, line breaks do occur). Anyway, what do I look for? Any large or suspicious number - but what exactly is "suspicious"? Anything above 1 second? Are we to believe the assignment of cost to pass, or could there be mis-attribution because result of an earlier pass is only forced later? Oh, and where do you want discussion of this feature (mailing list, ticket, ...)? I do hope that it will prove useful, in the sense that it could allow non-developers like me, or even build bots, to help spot performance problems. (E.g., you could advertise to enable this on travis. Yes, their build times depend on a lot of things, but still.) - J.W.

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New perf.haskell.org/ghc builder up
by Joachim Breitner 03 Dec '16

03 Dec '16

Hi, Brynmar, via Richard, has sponsored a new machine to build GHC commits for https://perf.haskell.org/ghc/ and I have set it up now. Since the numbers will be incomparable with the previous ones, I started the benchmarking from scratch, starting with 853cdaea7f8724cd071f4fa7ad6c5377a2a8a6e4 which was the last commit benchmarked before. The machine is churning through all commits of the last month at a speed of one commit per hour, so eventually https://perf.haskell.org/ghc/ will give information about up-to-date commits again. Greetings, Joachim -- Joachim “nomeata” Breitner mail(a)joachim-breitner.de • https://www.joachim-breitner.de/ XMPP: nomeata(a)joachim-breitner.de • OpenPGP-Key: 0xF0FBF51F Debian Developer: nomeata(a)debian.org

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Re: [GHC] #11744: Latest Xcode update violates POSIX compliance of `nm -P`
by George Colpitts 02 Dec '16

02 Dec '16

I can confirm that what Ben says is true for me using XCode 8.1 On Thu, Dec 1, 2016 at 6:21 PM GHC <ghc-devs(a)haskell.org> wrote: > #11744: Latest Xcode update violates POSIX compliance of `nm -P` > ---------------------------------+-------------------------------------- > Reporter: hvr | Owner: > Type: bug | Status: new > Priority: highest | Milestone: > Component: Build System | Version: > Resolution: | Keywords: > Operating System: MacOS X | Architecture: x86_64 (amd64) > Type of failure: None/Unknown | Test Case: > Blocked By: | Blocking: > Related Tickets: | Differential Rev(s): phab:D2113 > Wiki Page: | > ---------------------------------+-------------------------------------- > > Comment (by bgamari): > > It actually appears that the latest XCode release (8.1) fixes this. It > shouldn't be necessary to use `nm-classic` with, > {{{ > $ nm --version > Apple LLVM version 8.0.0 (clang-800.0.38) > Optimized build. > Default target: x86_64-apple-darwin16.0.0 > Host CPU: haswell > }}} > > -- > Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11744#comment:20> > GHC <http://www.haskell.org/ghc/> > The Glasgow Haskell Compiler >

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testsuite broken
by Simon Peyton Jones 02 Dec '16

02 Dec '16

Yikes. I can’t run the testsuite on Linux (debian ? I think…). See below. I installed python3 by saying apt-get install python3 And indeed python3 --version Python 3.2.3 This is bad. Can anyone help? Simon PYTHON="python3" "python3" ../../driver/runtests.py -e ghc_compiler_always_flags="'-dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -dno-debug-output'" -e config.compiler_debugged=True -e ghc_with_native_codegen=1 -e config.have_vanilla=True -e config.have_dynamic=True -e config.have_profiling=False -e ghc_with_threaded_rts=1 -e ghc_with_dynamic_rts=1 -e config.have_interp=False -e config.unregisterised=False -e config.ghc_dynamic_by_default=False -e config.ghc_dynamic=False -e ghc_with_smp=1 -e ghc_with_llvm=0 -e windows=False -e darwin=False -e config.in_tree_compiler=True --threads=33 -e config.cleanup=True -e config.local=False --rootdir=. --configfile=../../config/ghc -e 'config.confdir="../../config"' -e 'config.platform="x86_64-unknown-linux"' -e 'config.os="linux"' -e 'config.arch="x86_64"' -e 'config.wordsize="64"' -e 'config.timeout=int() or config.timeout' -e 'config.exeext=""' -e 'config.top="/5playpen/simonpj/HEAD-4/testsuite"' --config 'compiler="/5playpen/simonpj/HEAD-4/inplace/test spaces/ghc-stage1"' --config 'ghc_pkg="/5playpen/simonpj/HEAD-4/inplace/test spaces/ghc-pkg"' --config 'haddock="/5playpen/simonpj/HEAD-4/inplace/test spaces/haddock"' --config 'hp2ps="/5playpen/simonpj/HEAD-4/inplace/test spaces/hp2ps"' --config 'hpc="/5playpen/simonpj/HEAD-4/inplace/test spaces/hpc"' --config 'gs="gs"' --config 'timeout_prog="../../timeout/install-inplace/bin/timeout"' -e "config.stage=1" --summary-file "../../../testsuite_summary_stage1.txt" --no-print-summary 1 \ \ \ \ \ \ -e config.speed="2" \ Traceback (most recent call last): File "../../driver/runtests.py", line 210, in <module> from testlib import * File "/home/simonpj/code/HEAD-4/testsuite/driver/testlib.py", line 1286 f.write(u':set prog ' + name + u'\n') ^ SyntaxError: invalid syntax

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Compiling on OpenBSD-current
by Adam Steen 01 Dec '16

01 Dec '16

Hi When Compiling on OpenBSD-Current I get the follow error, what do i need to do to fix this? Cheers Adam ===--- building phase 0 gmake --no-print-directory -f ghc.mk phase=0 phase_0_builds gmake[1]: Nothing to be done for 'phase_0_builds'. ===--- building phase 1 gmake --no-print-directory -f ghc.mk phase=1 phase_1_builds "/usr/local/bin/ghc" -o utils/hsc2hs/dist/build/tmp/hsc2hs -hisuf hi -osuf o -hcsuf hc -static -O0 -H64m -Wall -package-db libraries/bootstrapping.conf -hide-all-packages -i -iutils/hsc2hs/. -iutils/hsc2hs/dist/build -Iutils/hsc2hs/dist/build -iutils/hsc2hs/dist/build/hsc2hs/autogen -Iutils/hsc2hs/dist/build/hsc2hs/autogen -optP-include -optPutils/hsc2hs/dist/build/hsc2hs/autogen/cabal_macros.h -package-id base-4.9.0.0 -package-id containers-0.5.7.1 -package-id directory-1.2.6.2 -package-id filepath-1.4.1.0 -package-id process-1.4.2.0 -XHaskell2010 -no-user-package-db -rtsopts -odir utils/hsc2hs/dist/build -hidir utils/hsc2hs/dist/build -stubdir utils/hsc2hs/dist/build -optl-z -optlwxneeded -static -O0 -H64m -Wall -package-db libraries/bootstrapping.conf -hide-all-packages -i -iutils/hsc2hs/. -iutils/hsc2hs/dist/build -Iutils/hsc2hs/dist/build -iutils/hsc2hs/dist/build/hsc2hs/autogen -Iutils/hsc2hs/dist/build/hsc2hs/autogen -optP-include -optPutils/hsc2hs/dist/build/hsc2hs/autogen/cabal_macros.h -package-id base-4.9.0.0 -package-id containers-0.5.7.1 -package-id directory-1.2.6.2 -package-id filepath-1.4.1.0 -package-id process-1.4.2.0 -XHaskell2010 -no-user-package-db -rtsopts utils/hsc2hs/dist/build/Main.o utils/hsc2hs/dist/build/C.o utils/hsc2hs/dist/build/Common.o utils/hsc2hs/dist/build/CrossCodegen.o utils/hsc2hs/dist/build/DirectCodegen.o utils/hsc2hs/dist/build/Flags.o utils/hsc2hs/dist/build/HSCParser.o utils/hsc2hs/dist/build/UtilsCodegen.o utils/hsc2hs/dist/build/Paths_hsc2hs.o <no location info>: error: Warning: Couldn't figure out linker information! Make sure you're using GNU ld, GNU gold or the built in OS X linker, etc. cc: wxneeded: No such file or directory `cc' failed in phase `Linker'. (Exit code: 1) compiler/ghc.mk:580: compiler/stage1/build/.depend-v.haskell: No such file or directory gmake[1]: *** [utils/hsc2hs/ghc.mk:15: utils/hsc2hs/dist/build/tmp/hsc2hs] Error 1 gmake: *** [Makefile:125: all] Error 2

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