April 2017 - ghc-tickets

[GHC] #13527: ghc has a stack space leak when prints warnings
by GHC 21 Apr '17

21 Apr '17

#13527: ghc has a stack space leak when prints warnings -------------------------------------+------------------------------------- Reporter: slyfox | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- Found on a crash when ghc tried to print a warning in a huge assembly file. I've simplified it to autogenerated C file with an error: {{{ # generate 10 million lines file # and put an error into the very end of file $ { for i in `seq 1 $((10 * 1000 * 1000))`; do echo "// a comment number $i"; done; echo 'static int foo = ;'; } > a.c }}} {{{ $ LANG=C powerpc64le-unknown-linux-gnu-ghc -c a.c +RTS -K128M stack overflow: use +RTS -K<size> to increase it }}} C compiler tried to output something like the following to stderr: {{{ a.c:10000001:0: error: error: expected expression before ';' token static int foo = ; }}} GHC finds 'a.c:10000001' location and tries to pretty-print the line. We get a space leak somewhere. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13527> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9210: "overlapping instances" through FunctionalDependencies
by GHC 21 Apr '17

21 Apr '17

#9210: "overlapping instances" through FunctionalDependencies -------------------------------------------+------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.8.1 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: -------------------------------------------+------------------------------- This program prints `("1",2)`, but if you reverse the order of the two instances, it prints `(1,"2")`. {{{ {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE FunctionalDependencies #-} -- extracted from http://lpaste.net/105656 import Control.Applicative import Data.Functor.Identity modify :: ((a -> Identity b) -> s -> Identity t) -> (a -> b) -> (s -> t) modify l f s = runIdentity (l (Identity . f) s) class Foo s t a b | a b s -> t where foo :: Applicative f => (a -> f b) -> s -> f t instance Foo (x, a) (y, a) x y where foo f (a,b) = (\fa -> (fa,b)) <$> f a instance Foo (a, x) (a, y) x y where foo f (a,b) = (\fb -> (a,fb)) <$> f b main = print $ modify foo (show :: Int -> String) (1 :: Int, 2 :: Int) }}} Note that the two instances involved `Foo (Int, Int) (String, Int) Int String` and `Foo (Int, Int) (Int, String) Int String` are not actually overlapping. But, they have the same `a`, `b`, and `s` fields and it seems that this makes GHC think that either one is equally valid, thanks to the fundep. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9210> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13495: ghc-stage1: panic! (the 'impossible' happened) creating cross compiler for PPC
by GHC 20 Apr '17

20 Apr '17

#13495: ghc-stage1: panic! (the 'impossible' happened) creating cross compiler for PPC --------------------------------+---------------------------------------- Reporter: jms | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: powerpc | Type of failure: Building GHC failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+---------------------------------------- We have a product based on a Freescale MPC8544E. I have previously built powerpc-unknown-linux-gnuspe-ghc-7.8.3 and that produces viable code though annoyingly rather large binaries but this is covered elsewhere. I looked at both 7.8.4 and 7.10 a while ago but they proved to be non- starters for reasons I no longer remember. Now for reasons tooling reasons (Stack and friends) it would be nice to use 8.0.2 My procedure is as follows In the (ghc-7.83 or) ghc-8.0.2 source directory base=powerpc-unknown-linux-gnuspe; ./configure --prefix=/tmp/prefix --target=$base --with-gcc=$base-gcc --with-ld=$base-ld --with-nm=$base-nm --with-ar=$base-ar --with-ranlib=$base-ranlib --enable-unregisterised I edit mk/build.mk to make flavour "quick-cross" I edit ghc.mk and comment out anything with haskeline or terminfo The bottom of settings says ("Unregisterised", "YES"), ("LLVM llc command", "/usr/bin/llc-3.7"), ("LLVM opt command", "/usr/bin/opt-3.7") But the make itself (on Ubuntu 16 amd64) fails. "inplace/bin/ghc-stage1" -hisuf hi -osuf o -hcsuf hc -static -O0 -H64m -Wall -this-unit-id ghc-prim-0.5.0.0 -hide-all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -ilibraries /ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/dist- install/build -Ilibraries/ghc-prim/dist-install/build/autogen -Ilibraries /ghc-prim/. -optP-include -optPlibraries/ghc-prim/dist- install/build/autogen/cabal_macros.h -package-id rts -this-unit-id ghc- prim -XHaskell2010 -O -fllvm -no-user-package-db -rtsopts -Wno- trustworthy-safe -Wno-deprecated-flags -Wnoncanonical-monad-instances -odir libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim /dist-install/build -stubdir libraries/ghc-prim/dist-install/build -c libraries/ghc-prim/./GHC/Types.hs -o libraries/ghc-prim/dist- install/build/GHC/Types.o ghc-stage1: panic! (the 'impossible' happened) (GHC version 8.0.2 for powerpc-unknown-linux): LlvmCodeGen.Ppr: Cross compiling without valid target info. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13495> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13597: ghc: panic! (the 'impossible' happened)
by GHC 20 Apr '17

20 Apr '17

#13597: ghc: panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: rzil | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: MacOS X Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{ Downloading stack-1.4.0... Configuring stack-1.4.0... Building stack-1.4.0... Failed to install stack-1.4.0 Build log ( /Users/ruben/.cabal/logs/stack-1.4.0.log ): cabal: Entering directory '/var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T/cabal- tmp-4956/stack-1.4.0' [1 of 1] Compiling Main ( /var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T/cabal- tmp-4956/stack-1.4.0/dist/setup/setup.hs, /var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T/cabal- tmp-4956/stack-1.4.0/dist/setup/Main.o ) Linking /var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T/cabal- tmp-4956/stack-1.4.0/dist/setup/setup ... Configuring stack-1.4.0... Building stack-1.4.0... Preprocessing library stack-1.4.0... [ 1 of 124] Compiling Text.PrettyPrint.Leijen.Extended ( src/Text/PrettyPrint/Leijen/Extended.hs, dist/build/Text/PrettyPrint/Leijen/Extended.o ) [ 2 of 124] Compiling Hackage.Security.Client.Repository.HttpLib.HttpClient ( src/Hackage/Security/Client/Repository/HttpLib/HttpClient.hs, dist/build/Hackage/Security/Client/Repository/HttpLib/HttpClient.o ) [ 3 of 124] Compiling Stack.Options.ScriptParser ( src/Stack/Options/ScriptParser.hs, dist/build/Stack/Options/ScriptParser.o ) [ 4 of 124] Compiling Stack.Ghci.Script ( src/Stack/Ghci/Script.hs, dist/build/Stack/Ghci/Script.o ) [ 5 of 124] Compiling Stack.FileWatch ( src/Stack/FileWatch.hs, dist/build/Stack/FileWatch.o ) [ 6 of 124] Compiling System.Process.PagerEditor ( src/System/Process/PagerEditor.hs, dist/build/System/Process/PagerEditor.o ) [ 7 of 124] Compiling System.Process.Log ( src/System/Process/Log.hs, dist/build/System/Process/Log.o ) [ 8 of 124] Compiling Paths_stack ( dist/build/autogen/Paths_stack.hs, dist/build/Paths_stack.o ) [ 9 of 124] Compiling Path.Find ( src/Path/Find.hs, dist/build/Path/Find.o ) [ 10 of 124] Compiling Path.Extra ( src/Path/Extra.hs, dist/build/Path/Extra.o ) [ 11 of 124] Compiling System.Process.Read ( src/System/Process/Read.hs, dist/build/System/Process/Read.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-apple-darwin): Loading temp shared object failed: dlopen(/var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T/ghc17927_0/libghc_85.dylib, 5): no suitable image found. Did find: /var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T/ghc17927_0/libghc_85.dylib: malformed mach-o: load commands size (39456) > 32768 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug cabal: Leaving directory '/var/folders/sr/jktws8p56m58qw9h6k53dbfr0000gn/T /cabal-tmp-4956/stack-1.4.0' cabal: Error: some packages failed to install: stack-1.4.0 failed during the building phase. The exception was: ExitFailure 1 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13597> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13589: Possible inconsistency in CSE's treatment of NOINLINE
by GHC 20 Apr '17

20 Apr '17

#13589: Possible inconsistency in CSE's treatment of NOINLINE -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) 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 debugging #13535 I noticed the following inconsistency in CSE: `Note [CSE for INLINE and NOINLINE]` states that we need to take care when adding expressions bound to binders with inline pragmas to the `CSEnv`. To see why, consider the following, {{{#!hs {-# NOINLINE bar #-} bar = <rhs> -- Same rhs as foo foo = <rhs> }}} Given this program, we need to avoid producing `foo = bar` since doing so would mean that we would lose the ability to inline `foo`'s original RHS. The note then goes on to give the following rule, > We should not add > > {{{<rhs> :-> bar}}} > > to the CSEnv if `bar` has any constraints on when it can inline; > that is, if its 'activation' not always active. Otherwise we > might replace `<rhs>` by `bar`, and then later be unable to see that it > really was `<rhs>`. This rule is implemented in `noCSE` with, {{{#!hs not (isAlwaysActive (idInlineActivation id)) }}} However, it's quite unclear to me that this rule avoids the issue we set out to solve. Afterall, `NOINLINE bar` is always active, but it still means that rewriting `foo` to `foo=bar` would lose us the ability to see `foo`'s original RHS. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13589> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13592: Newtype type class with compiler generated instances
by GHC 20 Apr '17

20 Apr '17

#13592: Newtype type class with compiler generated instances -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature | Status: new request | 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: -------------------------------------+------------------------------------- Define a `Newtype` class, autmatically generating instances {{{#!hs class Newtype n where type O n :: Type pack :: O n -> n unpack :: n -> O n }}} as defined in Conal's [http://conal.net/papers/generic-parallel-functional /generic-parallel-functional.pdf Generic parallel functional programming] but also found in the [https://hackage.haskell.org/package/newtype-0.2 newtype] and [https://hackage.haskell.org/package/lens-4.15.1/docs /Control-Lens-Wrapped.html lens] packages. I run into this class every once in a while -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13592> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13411: GCC driver fails on Windows 10 15019+
by GHC 20 Apr '17

20 Apr '17

#13411: GCC driver fails on Windows 10 15019+ -------------------------------------+------------------------------------- Reporter: Phyx- | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Driver | Version: 8.0.2 Keywords: | Operating System: Windows Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Our GCC driver seems to be failing with a compatibility error on Windows 10 Insider builds 15019+. Leaving error code 0xc0000142. This driver has been unchanged since Windows XP and may just need some old APIs replaced. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13411> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4092: Floating point manipulation : ulp and coerce IEEE-754 Double# into Word64#
by GHC 20 Apr '17

20 Apr '17

#4092: Floating point manipulation : ulp and coerce IEEE-754 Double# into Word64# -------------------------------------+------------------------------------- Reporter: malosh | Owner: (none) Type: feature request | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 6.12.2 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): phab:D3358 Wiki Page: | -------------------------------------+------------------------------------- Changes (by erikd): * status: new => closed * resolution: => fixed Comment: This was implemented in: {{{ commit aa206346e6f12c9f88fdf051185741761ea88fbb Author: Erik de Castro Lopo <erikd(a)mega-nerd.com> Date: Wed Apr 12 14:09:49 2017 -0400 base: Implement bit casts between word and float types Test Plan: Test on x86 and x86_64 Reviewers: duncan, trofi, simonmar, tibbe, hvr, austin, rwbarton, bgamari Reviewed By: duncan Subscribers: Phyx, DemiMarie, rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3358 }}} Unfortunately too late for the ghc-8.2 release, but it will make the ghc-8.4 release. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4092#comment:30> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13501: TH segmentation fault on Linux when calling function from another package
by GHC 20 Apr '17

20 Apr '17

#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The bug was hit when using Buck (buckbuild.com) to build. I had two packages, A containing a single module with a TH function of type `TH.Q [TH.Dec]` and module B importing A it and calling that function at top-level. I've attached a tarball that reproduces the problem. I've verified that the problem occurs with 7.10.3, 8.0.2 and a semi-recent GHC HEAD from @bitonic. The issue doesn't occur on macOS and does not occur when the modules are in a single package or if the package is compiled as a shared library. The problem also does not occur when using stack, so this is likely related to how buck creates packages. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13501> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13458: Panic with unsafeCoerce and -dcore-lint
by GHC 20 Apr '17

20 Apr '17

#13458: Panic with unsafeCoerce and -dcore-lint -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE MagicHash, TypeInType, ScopedTypeVariables #-} module UIOST where import GHC.Exts import Data.Kind import Unsafe.Coerce unsafeCoerce' :: forall (r :: RuntimeRep) (a :: TYPE r) (b :: TYPE r). a -> b unsafeCoerce' = unsafeCoerce unsafeCoerce }}} Compiling this with optimization and `-dcore-lint` produces a panic: {{{ ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.1.20170308 for x86_64-unknown-linux): runtimeRepPrimRep typePrimRep (a_aW7 :: TYPE r_aW6) r_aW6 Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1191:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1195:37 in ghc:Outputable pprPanic, called at compiler/simplStg/RepType.hs:360:5 in ghc:RepType }}} Using `unsafeCoerce# unsafeCoerce` produces the panic without optimization. I have not been able to reproduce the problem without `-dcore-lint`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13458> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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