September 2016 - ghc-tickets

[GHC] #10858: Smaller generated instances
by GHC 05 Sep '16

05 Sep '16

#10858: Smaller generated instances -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- With very large modules with lots of deriving code, GHC spends quite some time compiling. I believe that we can improve things by reducing the size of the generated code. (More in the comments) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10858> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 21

Re: [GHC] #5615: ghc produces poor code for `div` with constant powers of 2.
by GHC 05 Sep '16

05 Sep '16

#5615: ghc produces poor code for `div` with constant powers of 2. -------------------------------------+------------------------------------- Reporter: Lennart | Owner: akio Type: bug | Status: closed Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.4.1-rc1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: x86 Type of failure: Runtime | Test Case: performance bug | Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2486 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => closed * resolution: => fixed * milestone: => 8.2.1 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5615#comment:32> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #5615: ghc produces poor code for `div` with constant powers of 2.
by GHC 05 Sep '16

05 Sep '16

#5615: ghc produces poor code for `div` with constant powers of 2. -------------------------------------+------------------------------------- Reporter: Lennart | Owner: akio Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86 Type of failure: Runtime | Test Case: performance bug | Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2486 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"6ea62427de419ea071e1ea79ad0c15d9f4e90a67/ghc" 6ea6242/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="6ea62427de419ea071e1ea79ad0c15d9f4e90a67" Turn divInt# and modInt# into bitwise operations when possible This implements #5615 for divInt# and modInt#. I also included rules to do constant-folding when the both arguments are known. Test Plan: validate Reviewers: austin, simonmar, bgamari Reviewed By: bgamari Subscribers: hvr, thomie Differential Revision: https://phabricator.haskell.org/D2486 GHC Trac Issues: #5615 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5615#comment:31> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #4806: Make error message more user friendly when module is not found because package is unusable
by GHC 05 Sep '16

05 Sep '16

#4806: Make error message more user friendly when module is not found because package is unusable -------------------------------------+------------------------------------- Reporter: mitar | Owner: bollu Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by mpickering): You could also make a sandbox and damage the sandbox package database? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4806#comment:18> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #4806: Make error message more user friendly when module is not found because package is unusable
by GHC 05 Sep '16

05 Sep '16

#4806: Make error message more user friendly when module is not found because package is unusable -------------------------------------+------------------------------------- Reporter: mitar | Owner: bollu Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Phyx-): @bollu, yeah, that seems like a reasonable thing to do, but I wouldn't go messing with your stage0 compiler (e.g. the one you use to compile the git source with the first time). Just do a normal compile and corrpupt the stage2 compiler in the folder `inplace` that gets created. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4806#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

[GHC] #12571: GHC panic
by GHC 05 Sep '16

05 Sep '16

#12571: GHC panic -------------------------------------+------------------------------------- Reporter: prsteele | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I received the following error message from GHC: {{{ <no location info>: ghc: panic! (the 'impossible' happened) (GHC version 7.10.3 for x86_64-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone $fStorableWord21 To increase the limit, use -fsimpl-tick-factor=N (default 100) If you need to do this, let GHC HQ know, and what factor you needed To see detailed counts use -ddump-simpl-stats Total ticks: 8040 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} When I followed the suggestion of adding `-fsimpl-tick-factor=200` the compiler proceeds normally (finding a syntax error in a file). Removing this option, strangely, also causes the compiler to proceed normally. I can no longer reproduce this bug, although several compilations in a row (before adding the option) reproduced the bug. Although I cannot reproduce this bug, the syntax error that is present came from an error of the form: {{{#!hs f :: A -> M B f a = do x <- g a let c = h a in do ... }}} The actual file is attached. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12571> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 8

[GHC] #12566: Memory leak
by GHC 05 Sep '16

05 Sep '16

#12566: Memory leak -------------------------------------+------------------------------------- Reporter: igloo | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- With the attached write.hs (which generates a file called "data") and read.hs (which consumes that file), if I run {{{ ghc -Wall -Werror -O write.hs -o write ghc -Wall -Werror -O -prof -auto-all read.hs -o read1 ghc -Wall -Werror -O -prof -auto-all read.hs -o read2 -DLEAK ./write ./read1 +RTS -h ./read2 +RTS -h }}} then read2's heap profile shows that it is retaining a lot of extra data. Perhaps I am missing something, but I can't see why this needs to be retained. I would expect the two heap profiles to look the same. Sources and heap profiles (using GHC 8.0.1) attached. I've copied the sources below for convenience: write.hs: {{{#!hs module Main (main) where import qualified Data.ByteString.Lazy.Char8 as L main :: IO () main = L.writeFile "data" $ L.concat $ map mkByteString [1..100000] mkByteString :: Int -> L.ByteString mkByteString i = L.concat (L.pack ("#" ++ show i ++ "\n") : replicate 100 (L.pack "Something else\n")) }}} read.hs: {{{#!hs {-# LANGUAGE BangPatterns, CPP #-} module Main (main) where import Data.List import Data.Set (Set) import qualified Data.Set as Set import qualified Data.ByteString.Char8 as S import qualified Data.ByteString.Lazy.Char8 as L main :: IO () main = do bs <- L.readFile "data" let stats = getMaybes bs s = mkSet stats print $ Set.size s mkSet :: [Maybe S.ByteString] -> Set S.ByteString mkSet ms = foldl' f Set.empty ms where f s (Just l) = Set.insert l s f s _ = s getMaybes :: L.ByteString -> [Maybe S.ByteString] getMaybes bs = if L.null bs then [] else case getMaybe bs of (stat, bs') -> stat : getMaybes bs' getMaybe :: L.ByteString -> (Maybe S.ByteString, L.ByteString) getMaybe bs = case L.uncons bs of Just ('#', bs') -> case L.break ('\n' ==) bs' of (l, bs'') -> let !l' = copy l in (Just l', bs'') _ -> case L.break ('\n' ==) bs of (_x, bs') -> #ifdef LEAK copy _x `seq` #endif (Nothing, L.tail bs') copy :: L.ByteString -> S.ByteString copy bs = S.copy $ L.toStrict bs }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12566> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 5

Re: [GHC] #4806: Make error message more user friendly when module is not found because package is unusable
by GHC 05 Sep '16

05 Sep '16

#4806: Make error message more user friendly when module is not found because package is unusable -------------------------------------+------------------------------------- Reporter: mitar | Owner: bollu Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bollu): How do I reproduce this, exactly? If I'm fixing this, I'll need to know when the bug is fixed, so I was wondering what the correct way to reproduce this is. Do I damage my package database on purpose? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4806#comment:16> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

[GHC] #12570: Different behaviour in Linux and Mac OS when using some locale environments
by GHC 04 Sep '16

04 Sep '16

#12570: Different behaviour in Linux and Mac OS when using some locale environments -------------------------------------+------------------------------------- Reporter: asr | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- While reporting [https://github.com/malcolmwallace/cpphs/issues/6 this] cpphs issue, we found the following behaviour: {{{ $ echo -e '\u2200' > test $ LC_CTYPE=C ghc -e 'putStr =<< readFile "test"' }}} In Ubuntu, we get the error {{{ <interactive>: test: hGetContents: invalid argument (invalid byte sequence) }}} but in Mac OS the output is {{{ ∀ }}} GHC version: 8.0.1 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12570> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

Re: [GHC] #4806: Make error message more user friendly when module is not found because package is unusable
by GHC 04 Sep '16

04 Sep '16

#4806: Make error message more user friendly when module is not found because package is unusable -------------------------------------+------------------------------------- Reporter: mitar | Owner: bollu Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by Phyx-): * cc: Phyx- (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4806#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0