July 2015 - ghc-tickets

[GHC] #10527: Panic Simplifier ticks exhausted with type families
by GHC 08 Dec '15

08 Dec '15

#10527: Panic Simplifier ticks exhausted with type families -------------------------------------+------------------------------------- Reporter: sopvop | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I've tried to compile my vinyl-like records with 7.10.2-rc1 and got: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.10.1.20150612 for x86_64-unknown-linux): Simplifier ticks exhausted When trying RuleFired Class op rreplace 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: 225484 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Attached self contained test compiles with 7.10.1, but fails with 7.10.2-rc1 when compiled with optimizations. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10527> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10653: PatternSynonyms should be imported/exported as part of the wildcard notation
by GHC 08 Dec '15

08 Dec '15

#10653: PatternSynonyms should be imported/exported as part of the wildcard notation -------------------------------------+------------------------------------- Reporter: gridaphobe | Owner: Type: feature | Status: new request | Milestone: 7.12.1 Priority: normal | Version: 7.11 Component: Compiler | Operating System: Unknown/Multiple Keywords: pattern | Type of failure: None/Unknown synonyms | Blocked By: Architecture: | Related Tickets: Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Suppose I have the following two modules. {{{#!hs {-# LANGUAGE PatternSynonyms #-} module A where data A = A2 Int Int pattern A1 a <- A2 a _ where A1 a = A2 a 0 }}} {{{#!hs module B where import A ( A(..) ) a = A1 0 }}} When I try to compile `B.hs` I get an error because `A1` is unbound in module `B`. {{{ $ ghc --make B.hs [1 of 2] Compiling A ( A.hs, A.o ) [2 of 2] Compiling B ( B.hs, B.o ) B.hs:5:5: Not in scope: data constructor ‘A1’ Perhaps you meant ‘A2’ (imported from A) }}} The issue is that the import `A(..)` brings all of `A`s data constructors and accessors into scope, but not any associated pattern synonyms. Instead I have to enable `PatternSynonyms` in module `B` (or just import everything from `A`). {{{#!hs {-# LANGUAGE PatternSynonyms #-} module B where import A ( A(..), pattern A1 ) a = A1 0 }}} I'd like to propose that we extend the semantics of the `A(..)` import/export notation to include any associated pattern synonyms. I think this is in line with the spirit of `PatternSynonyms`, that the extension should allow internal refactoring without causing API breakage, and that the extension should only need to be enabled to *define* pattern synonyms. FYI, this issue does appear in the wild, I ran into it while working on https://phabricator.haskell.org/D861 and had to modify two import lists in Cabal. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10653> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10444: Tex.Read.Lex.lex broken
by GHC 07 Dec '15

07 Dec '15

#10444: Tex.Read.Lex.lex broken -------------------------------------+------------------------------------- Reporter: strake888 | Owner: ekmett Type: bug | Status: new Priority: normal | Milestone: Component: Core | Version: 7.10.1 Libraries | Operating System: Unknown/Multiple Keywords: | Type of failure: Incorrect result Architecture: | at runtime Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- {{{ Prelude> lex "&) = mempty" [("&",") = mempty")] Prelude> lex "∘) = mempty" [] }}} I traced this problem to Text.Read.Lex.lex -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10444> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8245: ghc-pkg list prints packages in non-alphabetical order
by GHC 07 Dec '15

07 Dec '15

#8245: ghc-pkg list prints packages in non-alphabetical order ------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Instead, it prints the ones with the smallest version first. That does not make much sense. I will attach a patch. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8245> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9015: A documented way to differentiate between statements, declarations, imports, etc.
by GHC 07 Dec '15

07 Dec '15

#9015: A documented way to differentiate between statements, declarations, imports, etc. -------------------------------------+------------------------------------- Reporter: splinterofchaos | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: GHC API | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Documentation Difficulty: Moderate (less | bug than a day) | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- I'm working on a little REPL and the GHC API seems to supply two functions for evaluating one line, without compiling and evaluating into an `HValue`, which doesn't seem to have an `Outputable` instace: `runStmt` and `runDecls`. As it turns out, I need slightly different code to run on declarations verses statements, so this makes sense, but given a random string from the user, how can I tell the difference? I don't see anything in the documentation about this. I took a look at ghci's source (https://github.com/ghc/ghc/blob/a6f2c852d49313fa8acea2deb3741ab86c6ef995/gh…] and it looks like they just peek at the first word of the input, and that may be correct and sufficient, but impossible to verify without looking at Haskell's grammar. But even if I did verify it, that doesn't make explicit the difference between what `runDecls` and `runStmt` will accept. For a contrived example, consider if GHC implemented a feature that allowed for a new type of decl. It might be enabled by a language extension which means that testing whether a string is a statement or declaration cannot be done purely as we have to check the dynflags. Furthermore, the client may not be aware of the extension and thus send the input to `runStmt` instead. It would seem to me that requiring the user to manually parse the input violates separation of concerns since truly GHC knows best what source GHC will accept. The user should not have to examine the input except for if they need to modify or interpret it as something other than Haskell source code. The GHC API should either document an example function for differentiating declarations from statements (and even import statements), supply one itself, or supply several along the lines of `isDecl, isStmt, isImport :: String -> Bool`. This would improve ease-of-use by making client code more obvious and correct. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9015> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9706: New block-structured heap organization for 64-bit
by GHC 05 Dec '15

05 Dec '15

#9706: New block-structured heap organization for 64-bit -------------------------------------+------------------------------------- Reporter: ezyang | Owner: simonmar Type: task | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I was having some discussion about GHC's block structured heap with Sergio Benitez and Adam Belay, and during the discussion it was suggested that the way GHC manages the block structured heap is suboptimal when we're on 64-bit architectures. At the moment, we allocate memory from the operating system per-megablock, storing metadata in the very first megablock. We have to do this because, on 32-bit, we can't generally be too picky about what address our memory ends up living. On 64-bits, we have a lot more flexibility. Here is the proposal: 1. Statically decide on a maximum heap size in a power of two. 2. Next, probe for some appropriately aligned chunk of available virtual address space for this. On POSIX, we can mmap /dev/null using PROT_NONE and MAP_NORESERVE. On Windows, we can use VirtualAlloc with MEM_RESERVE. (There are few other runtimes which do this trick, including GCC Go.) 3. Divide this region into blocks as before. The maximum heap size is now the megablock size, and the block size is still the same as before. Masking to find the block descriptor works as before. 4. To allocate, we keep track of the high-watermark, and mmap in 1MB pages as they are requested. We also keep track of how much metadata we need, and mmap extra pages to store metadata as necessary. We still want to request memory from the operating system in conveniently sized chunks, but we can now abolish the notion of a megablock and the megablock allocator, and work purely with block coalescing. Additionally, the recorded heap location means that we can check if a pointer is HEAP_ALLOCED using a mask and equality check, solving #8199. What do people think? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9706> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8582: Record syntax for pattern synonyms
by GHC 04 Dec '15

04 Dec '15

#8582: Record syntax for pattern synonyms ------------------------------------+------------------------------------- Reporter: cactus | Owner: cactus Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: 5144 | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Implement syntax for {{{ pattern Cons{car, cdr} = (car, cdr) }}} which can then be used just like a regular record constructor, so the following are all valid patterns: {{{ Cons (Just x) [] Cons{car = Just x} }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8582> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8098: Faulty Word64 arithmetic if optimized
by GHC 02 Dec '15

02 Dec '15

#8098: Faulty Word64 arithmetic if optimized ----------------------------+--------------------------------- Reporter: achp | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.2 Keywords: | Operating System: Windows Architecture: x86 | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------+--------------------------------- The following program produces different results depending on optimization: Checked.hs: {{{ module Checked ((.-.)) where (.-.) :: (Bounded a, Integral a) => a -> a -> Maybe a x .-. y | x >= 0 && y < 0 = if z > x then Just z else Nothing | x >= 0 = if z <= x then Just z else Nothing | x < 0 && y > 0 = if z < x then Just z else Nothing | otherwise = Just z where z = x - y }}} Main.hs: {{{ module Main (main) where import Data.Maybe import Data.Word import Numeric import Checked main :: IO () main = print $ showHex (fromJust ((0xFFFFFFFF00000000 :: Word64) .-. 0x00000000FFFFFFFF)) "" }}} {{{ D:\dev\haskell\ch1>ghc --make Checked.hs Main.hs [1 of 2] Compiling Checked ( Checked.hs, Checked.o ) [2 of 2] Compiling Main ( Main.hs, Main.o ) Linking Main.exe ... D:\dev\haskell\ch1>Main.exe "fffffffe00000001" D:\dev\haskell\ch1>del *.hi *.o *.exe D:\dev\haskell\ch1>ghc --make -O2 Checked.hs Main.hs [1 of 2] Compiling Checked ( Checked.hs, Checked.o ) [2 of 2] Compiling Main ( Main.hs, Main.o ) Linking Main.exe ... D:\dev\haskell\ch1>Main.exe "fffe00000001" D:\dev\haskell\ch1> }}} The bug disappears if definition and usage of (.-.) are in the same module. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8098> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10279: panic on haskell-src-exts
by GHC 27 Nov '15

27 Nov '15

#10279: panic on haskell-src-exts -------------------------------------+------------------------------------- Reporter: | Owner: throwaway123 | Status: new Type: bug | Milestone: Priority: normal | Version: 7.10.1 Component: Compiler | Operating System: Linux Keywords: | Type of failure: Compile-time Architecture: x86_64 | crash (amd64) | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Compiling `Bug.hs`: {{{ {-# LANGUAGE QuasiQuotes #-} import Language.Haskell.Exts.QQ (dec) main :: IO () main = return () where foo = [dec| bar = 3 |] }}} by `ghc --make -v -dcore-lint Bug.hs` gives {{{ ghc --make -v -dcore-lint Bug.hs Glasgow Haskell Compiler, Version 7.10.1, stage 2 booted by GHC version 7.8.4 Using binary package database: /usr/lib/ghc-7.10.1/package.conf.d/package.cache wired-in package ghc-prim mapped to ghc- prim-0.4.0.0-7c945cc0c41d3b7b70f3edd125671166 wired-in package integer-gmp mapped to integer- gmp-1.0.0.0-3c947e5fb6dca14804d9b2793c521b67 wired-in package base mapped to base-4.8.0.0-1b689eb8d72c4d4cc88f445839c1f01a wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.10.0.0-e895139a0ffff267d412e3d0191ce93b wired-in package ghc mapped to ghc-7.10.1-325809317787a897b7a97d646ceaa3a3 wired-in package dph-seq not found. wired-in package dph-par not found. Hsc static flags: wired-in package ghc-prim mapped to ghc- prim-0.4.0.0-7c945cc0c41d3b7b70f3edd125671166 wired-in package integer-gmp mapped to integer- gmp-1.0.0.0-3c947e5fb6dca14804d9b2793c521b67 wired-in package base mapped to base-4.8.0.0-1b689eb8d72c4d4cc88f445839c1f01a wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.10.0.0-e895139a0ffff267d412e3d0191ce93b wired-in package ghc mapped to ghc-7.10.1-325809317787a897b7a97d646ceaa3a3 wired-in package dph-seq not found. wired-in package dph-par not found. *** Chasing dependencies: Chasing modules from: *Bug.hs Stable obj: [] Stable BCO: [] Ready for upsweep [NONREC ModSummary { ms_hs_date = 2015-04-09 10:01:43.312180074 UTC ms_mod = Main, ms_textual_imps = [import (implicit) Prelude, import Language.Haskell.Exts.QQ ( dec )] ms_srcimps = [] }] *** Deleting temp files: Deleting: compile: input file Bug.hs Created temporary directory: /tmp/ghc7356_0 *** Checking old interface for Main: [1 of 1] Compiling Main ( Bug.hs, Bug.o ) *** Parser: *** Renamer/typechecker: *** Simplify: *** CorePrep: *** ByteCodeGen: Loading package ghc-prim-0.4.0.0 ... linking ... done. *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/integ_2aU3IZNMF9a7mQ0OzsZ0dS --print-file-name libgmp.so Loading package integer-gmp-1.0.0.0 ... linking ... done. Loading package base-4.8.0.0 ... linking ... done. Loading package array-0.5.1.0 ... linking ... done. Loading package filepath-1.4.0.0 ... linking ... done. Loading package deepseq-1.4.1.1 ... linking ... done. Loading package time-1.5.0.1 ... linking ... done. Loading package bytestring-0.10.6.0 ... linking ... done. *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name librt.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name libutil.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name libdl.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name libpthread.so Loading package unix-2.7.1.0 ... linking ... done. Loading package directory-1.2.2.0 ... linking ... done. Loading package old-locale-1.0.0.7 ... linking ... done. Loading package old-time-1.1.0.3 ... linking ... done. Loading package text-1.2.0.4 ... linking ... done. Loading package polyparse-1.11 ... linking ... done. Loading package cpphs-1.19 ... linking ... done. Loading package pretty-1.1.2.0 ... linking ... done. Loading package haskell-src-exts-1.16.0.1 ... linking ... done. Loading package syb-0.4.4 ... linking ... done. Loading package template-haskell-2.10.0.0 ... linking ... done. Loading package transformers-0.4.2.0 ... linking ... done. Loading package mtl-2.2.1 ... linking ... done. Loading package nats-1 ... linking ... done. Loading package th-lift-0.7.2 ... linking ... done. Loading package containers-0.5.6.2 ... linking ... done. Loading package safe-0.3.8 ... linking ... done. Loading package th-expand-syns-0.3.0.6 ... linking ... done. Loading package th-reify-many-0.1.3 ... linking ... done. Loading package th-orphans-0.11.1 ... linking ... done. Loading package haskell-src-meta-0.6.0.9 ... linking ... done. Loading package haskell-src-exts-qq-0.6.1 ... linking ... done. Bug.hs:8:16:*** Deleting temp files: Deleting: /tmp/ghc7356_0/ghc7356_1.s Warning: deleting non-existent /tmp/ghc7356_0/ghc7356_1.s *** Deleting temp dirs: Deleting: /tmp/ghc7356_0 ghc: panic! (the 'impossible' happened) (GHC version 7.10.1 for x86_64-unknown-linux): qual_pkg haskell-src-exts-1.16.0.1 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} on my machine: {{{ $ uname -a Linux io 3.19.3-1-ARCH #1 SMP PREEMPT Thu Mar 26 14:56:16 CET 2015 x86_64 GNU/Linux $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/lto- wrapper Target: x86_64-unknown-linux-gnu Configured with: /build/gcc/src/gcc-4.9-20150304/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --with-system-zlib --enable-__cxa_atexit --disable- libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-cloog-backend=isl --enable-lto --enable-plugin --enable-install- libiberty --with-linker-hash-style=gnu --disable-multilib --disable-werror --enable-checking=release Thread model: posix gcc version 4.9.2 20150304 (prerelease) (GCC) $ ghc-pkg list /usr/lib/ghc-7.10.1/package.conf.d Cabal-1.22.2.0 array-0.5.1.0 async-2.0.2 base-4.8.0.0 bin-package-db-0.0.0.0 binary-0.7.3.0 bytestring-0.10.6.0 containers-0.5.6.2 cpphs-1.19 deepseq-1.4.1.1 directory-1.2.2.0 filepath-1.4.0.0 ghc-7.10.1 ghc-paths-0.1.0.9 ghc-prim-0.4.0.0 haddock-api-2.16.0 haddock-library-1.2.0 haskeline-0.7.2.1 haskell-src-exts-1.16.0.1 haskell-src-exts-qq-0.6.1 haskell-src-meta-0.6.0.9 hoopl-3.10.0.2 hpc-0.6.0.2 integer-gmp-1.0.0.0 minisat-0.1.1 mtl-2.2.1 nats-1 old-locale-1.0.0.7 old-time-1.1.0.3 polyparse-1.11 pretty-1.1.2.0 process-1.2.3.0 rts-1.0 safe-0.3.8 satchmo-core-0.8.0 stm-2.4.4 syb-0.4.4 template-haskell-2.10.0.0 terminfo-0.4.0.1 text-1.2.0.4 th-expand-syns-0.3.0.6 th-lift-0.7.2 th-orphans-0.11.1 th-reify-many-0.1.3 time-1.5.0.1 transformers-0.4.2.0 unix-2.7.1.0 xhtml-3000.2.1 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10279> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10394: LLVM mangler doesn't mangle AVX instructions
by GHC 27 Nov '15

27 Nov '15

#10394: LLVM mangler doesn't mangle AVX instructions -------------------------------------+------------------------------------- Reporter: dobenour | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.11 (LLVM) | Operating System: Unknown/Multiple Keywords: | Type of failure: Runtime crash Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The LLVM mangler does not currently transform AVX instructions on x86-64 platforms, due to a missing #include. Also, it is significantly more complicated than necessary, due to the file into sections (not needed anymore), and is sensitive to the details of the whitespace in the assembly. I have attached a modified mangler that I believe to be simpler and more robust. I have not tested it, though, as I do not have a recent enough version of LLVM on my machine. I am marking this as `Runtime crash' because that is what would happen if the unchanged AVX instructions made their way into the executable. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10394> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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