March 2015 - ghc-tickets

[GHC] #10137: Rewrite switch code generation
by GHC 21 Jan '16

21 Jan '16

#10137: Rewrite switch code generation -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 (CodeGen) | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Inspired by #10124 I looked at the code generation for enumeration and integer types, and I think this can be improved in a few ways. My goals are: * Fancier code for integer types. Currently, the code for enumeration types will emit jump tables for dense choices; there is no reason to treat integer types differently. * The ability to behave differently if some of the cases are equal, and, as an extension of that, * The possibility to create branchless code if multiple checks would go to the same jump. The current scheme is roughly: * When we generate Cmm code for a STG case expression, we handle enumeration types and literals separately. * At this point, the decisions about what code to generate are made (jump tables (but only for enumeration types) or if-then-else trees). * The Common Block Optimization on Cmm happens later in the pipeline, making it non-trivial to detect branches that do the same thing. My plan is the following: * In the STG→Cmm transformation, floats will be handled separately. Matching against literals literals is fishy anyways, so my suggestion is to simply generate a linear list of equality checks here – turning the intended operation (equality test) into something else (comparisons in a if-then-else tree) feels wrong to me for floats. And the rest would not work well for floats, so I’d like to have them out of the way. * The case of enumeration types will be reduced to word literals, and treated the same from now on. * For integer types, no code generation decisions is made at this point. Instead, always a `CmmSwitch` statement is generated. * In a separate Cmm transformation pass, which will run /after/ the common block optimization, we visit all `CmmSwitches` and create proper code for them. I’d like to separate the algorithm that plans the code generation into a function (possibly even module) of its own, so that the decisions can easily by analyized and modified. The algorithm has a few choices to make: * If multiple values point to the same code, we can generate branchless code (`y := x == 1 || x == 5 || x = 7; if (y==0) then goto l1 else goto l2`). * If there are whole ranges pointing to the same code, the above can also use comparisons. * If there are dense ranges (i.e. a range with more than half of the possible values mapped to something), we want to generate jump tables from them (still `CmmSwitch` values). * Unless all options are handled by one of these possibilities, they need to be combined using `if-then-else` trees. The `CmmSwitch` constructor needs to change for that. It currently takes a `[Maybe Label]` argument, which is not suitable for before that pass, when its table may be sparse. I think an `IntMap Label` would work nicely. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10137> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9357: Kind-polymorphic type family accepts unlifted type arguments
by GHC 21 Jan '16

21 Jan '16

#9357: Kind-polymorphic type family accepts unlifted type arguments -------------------------------------+------------------------------------- Reporter: kosmikus | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.8.2 checker) | Operating System: Keywords: | Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: GHC Difficulty: Unknown | accepts invalid program Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- The following code is accepted by ghc-7.8.2 and ghc-7.6.3: {{{#!hs {-# LANGUAGE TypeFamilies, MagicHash, PolyKinds #-} import GHC.Exts type family F (a :: k) :: * type instance F Int# = () }}} In nearly all other places, it seems that unlifted types are explicitly forbidden. I'm also not allowed to actually apply `F` to `Int#` after defining the type family like this. So I think the compiler should probably reject the `type instance`. (BTW, is it actually clear that using `#` as an argument kind to a type family or as an index kind for a GADT is in any way harmful?) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9357> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9215: GHC 7.8.2 mingw-w64: symbol not found in link
by GHC 21 Jan '16

21 Jan '16

#9215: GHC 7.8.2 mingw-w64: symbol not found in link ------------------------------------+------------------------------------- Reporter: stuartallenmills | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- This includes calls such as strdup, stat, , and snprintf. These calls are not available in the 64 bit libraries (though 64 bit versions are such as _strdup, _snprintf) These problems have occurred in building yaml and unix-compat. They also occurred in system-fileio but jmilikin generated a patch for that library -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9215> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9182: Empty case analysis for function clauses
by GHC 21 Jan '16

21 Jan '16

#9182: Empty case analysis for function clauses ------------------------------------+------------------------------------- Reporter: dfranke | Owner: Type: feature request | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Thanks to `-XEmptyCase`, the following is legal: {{{ module Empty where data Empty empty :: Empty -> a empty x = case x of { } }}} However, if I leave off the last line, GHC will complain that `The type signature for ‘empty’ lacks an accompanying binding`. I think this program should be accepted. It isn't that I'm not giving a definition for `empty`; it's that I'm defining it to be a function with no accompanying equations, as could be represented in Template Haskell by $(return [FunD (mkName "empty") []]) Currently, this too is rejected, with GHC complaining `Function binding for ‘empty’ has no equations`. I think this should be legal, with an empty list of clauses in a function definition being treated the same way as an empty list of matches in a case expression. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9182> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9202: Strange Closure Type
by GHC 21 Jan '16

21 Jan '16

#9202: Strange Closure Type -------------------------------------+------------------------------------- Reporter: athanclark | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: strange-closure- | Operating System: Linux type | Type of failure: Compile-time Architecture: x86_64 (amd64) | crash Difficulty: Project (more | Test Case: than a week) | Blocking: Blocked By: | Related Tickets: | -------------------------------------+------------------------------------- Hello masters of the universe, I am here with a plea. I have recently installed GHC 7.8.2 and cabal-install 1.20.0.0 (following [https://gist.github.com/wting/8498731 this] guide), and have ran into a fun road block on the way to installing yesod-platform. I have had a few incidents of the 'strange closure type ###' error on this machine before, on the 7.6.x version available in Ubuntu's repository. I believe this failure is occuring when installing text, because that was the error that I got when installing attoparsec alone, but without a sandbox. I know (barely) better now, so when I went to install yesod-platform, I did a {{{cabal unpack $1 && cd $1* && cabal sandbox init && cabal install --only-dependencies && cabal build}}}, but I failed at preventing the error, still :( I've attached the output as output.txt, and I've also included my `lspci` and `lshw` outputs just for giggles :) I hope someone can direct me in the right direction, I would appreciate it tremendously. Thank you! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9202> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8114: GHC panic when building `thyme`
by GHC 17 Jan '16

17 Jan '16

#8114: GHC panic when building `thyme` -----------------------------------+--------------------------------------- Reporter: Ptharien's | Owner: Flame | Status: new Type: bug | Milestone: Priority: normal | Version: 7.6.3 Component: Compiler | Operating System: MacOS X Keywords: | Type of failure: Compile-time crash Architecture: x86_64 (amd64) | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- While attempting to build `thyme` from Hackage with core, stg, and cmm linting and -O2 enabled, GHC crashed with an internal panic. See attached terminal log. {{{ rrdhcp-10-32-234-247:thyme-0.2.4.1 Alexander$ ghc --version The Glorious Glasgow Haskell Compilation System, version 7.6.3 rrdhcp-10-32-234-247:thyme-0.2.4.1 Alexander$ cabal --version cabal-install version 1.16.0.2 using version 1.16.0 of the Cabal library rrdhcp-10-32-234-247:thyme-0.2.4.1 Alexander$ which ghc /usr/local/bin/ghc rrdhcp-10-32-234-247:thyme-0.2.4.1 Alexander$ which cabal /Users/Alexander/Library/Haskell/bin/cabal }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8114> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8613: simplifier ticks exhausted
by GHC 14 Jan '16

14 Jan '16

#8613: simplifier ticks exhausted ----------------------------------+---------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: Other Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+---------------------------- (Sent by chrisreade(a)mac.com ) Compiler giving up with simplifier ticks exhausted. Large amount of simplification may be going on to cause this. The problem goes away when using -fsimpl-tick-factor=1000 and the code runs. This is the session output without the flag (asking to have bug reported): chris$ ghc -O2 -rtsopts RedBlackStencilOpt.hs -v Glasgow Haskell Compiler, Version 7.6.3, stage 2 booted by GHC version 7.4.2 Using binary package database: /Library/Frameworks/GHC.framework/Versions/7.6.3-x86_64/usr/lib/ghc-7.6.3/package.conf.d/package.cache Using binary package database: /Users/chris/.ghc/x86_64-darwin-7.6.3/package.conf.d/package.cache hiding package binary-0.5.1.1 to avoid conflict with later version binary-0.6.4.0 hiding package Cabal-1.16.0 to avoid conflict with later version Cabal-1.18.1.1 wired-in package ghc-prim mapped to ghc- prim-0.3.0.0-d5221a8c8a269b66ab9a07bdc23317dd wired-in package integer-gmp mapped to integer- gmp-0.5.0.0-2f15426f5b53fe4c6490832f9b20d8d7 wired-in package base mapped to base-4.6.0.1-6c351d70a24d3e96f315cba68f3acf57 wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.8.0.0-c2c1b21dbbb37ace4b7dc26c966ec664 wired-in package dph-seq not found. wired-in package dph-par not found. Hsc static flags: -static *** Chasing dependencies: Chasing modules from: *RedBlackStencilOpt.hs Stable obj: [] Stable BCO: [] Ready for upsweep [NONREC ModSummary { ms_hs_date = 2013-12-13 13:12:37 UTC ms_mod = main:RedBlackStencilOpt, ms_textual_imps = [import (implicit) Prelude, import Data.Array.Repa.Stencil.Dim2 as A, import Data.Array.Repa.Stencil as A, import Data.Array.Repa as A] ms_srcimps = [] }] *** Deleting temp files: Deleting: compile: input file RedBlackStencilOpt.hs Created temporary directory: /var/folders/dz/m1mks1yn1bsft72zgh105sw40000gn/T/ghc93155_0 *** Checking old interface for main:RedBlackStencilOpt: [1 of 1] Compiling RedBlackStencilOpt ( RedBlackStencilOpt.hs, RedBlackStencilOpt.o ) *** Parser: *** Renamer/typechecker: *** Simplify: *** CorePrep: *** ByteCodeGen: Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. *** gcc: '/usr/bin/gcc' '-m64' '-fno-stack-protector' '-m64' '-L/Library/Frameworks/GHC.framework/Versions/7.6.3-x86_64/usr/lib/ghc-7.6.3/base-4.6.0.1' '--print-file-name' 'libiconv.dylib' Loading package base ... linking ... done. Loading package pretty-1.1.1.0 ... linking ... done. Loading package array-0.4.0.1 ... linking ... done. Loading package deepseq-1.3.0.1 ... linking ... done. Loading package containers-0.5.0.0 ... linking ... done. Loading package old-locale-1.0.0.5 ... linking ... done. Loading package time-1.4.0.1 ... linking ... done. Loading package random-1.0.1.1 ... linking ... done. Loading package template-haskell ... linking ... done. Loading package QuickCheck-2.6 ... linking ... done. Loading package bytestring-0.10.0.2 ... linking ... done. Loading package primitive-0.5.0.1 ... linking ... done. Loading package vector-0.10.0.1 ... linking ... done. Loading package repa-3.2.3.3 ... linking ... done. *** Simplify: *** CorePrep: *** ByteCodeGen: *** Desugar: Result size of Desugar (after optimization) = {terms: 900, types: 1,810, coercions: 340} *** Simplifier: Result size of Simplifier iteration=1 = {terms: 834, types: 1,757, coercions: 567} Result size of Simplifier iteration=2 = {terms: 830, types: 1,721, coercions: 567} Result size of Simplifier = {terms: 830, types: 1,721, coercions: 567} *** Specialise: Result size of Specialise = {terms: 830, types: 1,721, coercions: 567} *** Float out(FOS {Lam = Just 0, Consts = True, PAPs = False}): Result size of Float out(FOS {Lam = Just 0, Consts = True, PAPs = False}) = {terms: 993, types: 2,131, coercions: 567} *** Float inwards: Result size of Float inwards = {terms: 993, types: 2,131, coercions: 567} *** Simplifier: *** Deleting temp files: Deleting: /var/folders/dz/m1mks1yn1bsft72zgh105sw40000gn/T/ghc93155_0/ghc93155_0.s Warning: deleting non-existent /var/folders/dz/m1mks1yn1bsft72zgh105sw40000gn/T/ghc93155_0/ghc93155_0.s *** Deleting temp dirs: Deleting: /var/folders/dz/m1mks1yn1bsft72zgh105sw40000gn/T/ghc93155_0 ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-apple-darwin): Simplifier ticks exhausted When trying RuleFired Class op szipWith 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: 60402 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8613> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10070: Cross compiling from Linux to Windows with mising Win32 library
by GHC 14 Jan '16

14 Jan '16

#10070: Cross compiling from Linux to Windows with mising Win32 library -------------------------------------+------------------------------------- Reporter: erikd | Owner: erikd Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Build | Version: 7.11 System | Operating System: Unknown/Multiple Keywords: cross- | Type of failure: Building GHC compiling | failed Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- After applying the proposed patch from #9524, building a Linux to Windows cross-compiler terminates with: {{{ Configuring time-1.5.0.1... ghc-cabal: At least the following dependencies are missing: Win32 -any }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10070> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9048: armel: evacuate(static): strange closure type 0
by GHC 13 Jan '16

13 Jan '16

#9048: armel: evacuate(static): strange closure type 0 ------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I guess I need to document the build failures here, instead of just mentioning them on the mailing list: Building 7.8 on armel on Debian fails with {{{ chmod +x inplace/bin/runghc inplace/bin/dll-split compiler/stage2/build/.depend-v-p-dyn.haskell "DynFlags" "Annotations Avail Bag BasicTypes BinIface Binary Bitmap BlockId BooleanFormula BreakArray BufWrite BuildTyCl ByteCodeAsm ByteCodeInstr ByteCodeItbls CLabel Class CmdLineParser Cmm CmmCallConv CmmExpr CmmInfo CmmMachOp CmmNode CmmType CmmUtils CoAxiom ConLike CodeGen.Platform CodeGen.Platform.ARM CodeGen.Platform.NoRegs CodeGen.Platform.PPC CodeGen.Platform.PPC_Darwin CodeGen.Platform.SPARC CodeGen.Platform.X86 CodeGen.Platform.X86_64 Coercion Config Constants CoreArity CoreFVs CoreLint CoreSubst CoreSyn CoreTidy CoreUnfold CoreUtils CostCentre DataCon Demand Digraph DriverPhases DsMonad DynFlags Encoding ErrUtils Exception ExtsCompat46 FamInstEnv FastBool FastFunctions FastMutInt FastString FastTypes Finder Fingerprint FiniteMap ForeignCall Hooks Hoopl Hoopl.Dataflow HsBinds HsDecls HsDoc HsExpr HsImpExp HsLit HsPat HsSyn HsTypes HsUtils HscTypes IOEnv Id IdInfo IfaceEnv IfaceSyn IfaceType InstEnv InteractiveEvalTypes Kind ListSetOps Literal LoadIface Maybes MkCore MkGraph MkId Module MonadUtils Name NameEnv NameSet OccName OccurAnal OptCoercion OrdList Outputable PackageConfig Packages Pair Panic PatSyn PipelineMonad Platform PlatformConstants PprCmm PprCmmDecl PprCmmExpr PprCore PrelInfo PrelNames PrelRules Pretty PrimOp RdrName Reg RegClass Rules SMRep Serialized SrcLoc StaticFlags StgCmmArgRep StgCmmClosure StgCmmEnv StgCmmLayout StgCmmMonad StgCmmProf StgCmmTicky StgCmmUtils StgSyn Stream StringBuffer TcEvidence TcIface TcRnMonad TcRnTypes TcType TcTypeNats TrieMap TyCon Type TypeRep TysPrim TysWiredIn Unify UniqFM UniqSet UniqSupply Unique Util Var VarEnv VarSet" dll-split: internal error: evacuate(static): strange closure type 0 (GHC version 7.8.2 for arm_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug make[2]: *** [compiler/stage2/dll-split.stamp] Aborted make[2]: *** Waiting for unfinished jobs.... make[1]: *** [all] Error 2 }}} Unfortunately, I’m no expert in strange architectures, so I need help from all you arm-lovers out there... Can someone, for starters, confirm this on an arm machine, or is this Debian specific somehow? (Hardening flags have been disabled.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9048> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8736: GHCi doesn't load .dyn_o files appropriately
by GHC 10 Jan '16

10 Jan '16

#8736: GHCi doesn't load .dyn_o files appropriately ------------------------------------+------------------------------------- Reporter: thoughtpolice | Owner: thoughtpolice Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Now that GHCi generally defaults to dynamic linking, it handles dynamic object files. But it doesn't implicitly handle the `-dynamic-too` case appropriately: {{{ $ cat Test.hs main = return () $ ./inplace/bin/ghc-stage2 -dynamic Test.hs [1 of 1] Compiling Main ( Test.hs, Test.o ) Linking Test ... $ ./inplace/bin/ghc-stage2 --interactive Test GHCi, version 7.8.20140130: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Ok, modules loaded: Main. Prelude Main> ^D $ ./inplace/bin/ghc-stage2 -dynamic-too Test.hs [1 of 1] Compiling Main ( Test.hs, Test.o ) Linking Test ... $ ./inplace/bin/ghc-stage2 --interactive Test GHCi, version 7.8.20140130: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling Main ( Test.hs, interpreted ) Ok, modules loaded: Main. *Main> }}} Also: {{{ $ ./inplace/bin/ghc-stage2 --interactive Test.dyn_o GHCi, version 7.8.20140130: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Warning: ignoring unrecognised input `Test.dyn_o' Prelude> }}} but it does handle the `.o` case. This should all be fixed and merged to 7.8 since it'll likely be very annoying. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8736> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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