September 2014 - ghc-tickets

[GHC] #8278: Improve error message when the same type is imported from two different library versions
by GHC 14 Feb '16

14 Feb '16

#8278: Improve error message when the same type is imported from two different library versions ------------------------------------+------------------------------------- Reporter: Yuras | 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: | ------------------------------------+------------------------------------- When a package indirectly depends on different versions of the same library, ghc reports cryptic error: {{{ Couldn't match expected type `ByteString' with actual type `bytestring-0.9.2.1:Data.ByteString.Internal.ByteString' }}} Error contains fully qualified type with package name and version only when the type is imported from different versions on the library, so looks like ghc knows what is wrong. Is it possible to add something like the next: {{{ Note: ByteString is imported from different package versions: bytestring-0.9.2.1 and bytestring-0.10.0.1 }}} It is inspired by a number of StackOverflow questions (e.g. http://stackoverflow.com/questions/12576817/couldnt-match-expected-type- with-actual-type-error-when-using-codec-bmp/12577025#12577025, http://stackoverflow.com/questions/18767086/bytestring-to-lazy-text-and- vice-versa/18769431?noredirect=1#comment27676563_18769431) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8278> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9022: TH pretty printer and GHC parser semicolon placement mismatch
by GHC 12 Feb '16

12 Feb '16

#9022: TH pretty printer and GHC parser semicolon placement mismatch ----------------------------+---------------------------------------------- Reporter: roldugin | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 (Parser) | Operating System: Unknown/Multiple Keywords: | Type of failure: GHC rejects valid program Architecture: | Test Case: Unknown/Multiple | Blocking: Difficulty: Unknown | Blocked By: | Related Tickets: | ----------------------------+---------------------------------------------- In GHC 7.8 TemplateHaskell pretty printer started inserting explicit braces and semicolons. It puts semicolons at the end of the line as opposed to the beginning of the next line. This causes GHC to fail parsing if we try to compile the pretty printed code. {{{ $ cat Foo.hs module Main where import Language.Haskell.TH main = putStrLn $ pprint foo foo :: Dec foo = barD where barD = FunD ( mkName "bar" ) [ Clause manyArgs (NormalB barBody) [] ] barBody = DoE [letxStmt, retxStmt] letxStmt = LetS [ ValD (VarP xName) (NormalB $ LitE $ IntegerL 5) [] ] retxStmt = NoBindS $ AppE returnVarE xVarE xName = mkName "x" returnVarE = VarE $ mkName "return" xVarE = VarE xName manyArgs = map argP [0..9] argP n = VarP $ mkName $ "arg" ++ show n $ ghc-7.8.2 Foo.hs [1 of 1] Compiling Main ( Foo.hs, Foo.o ) Linking Foo ... $ ./Foo | tee Bar.hs bar arg0 arg1 arg2 arg3 arg4 arg5 arg6 arg7 arg8 arg9 = do {let x = 5; return x} $ ghc Bar.hs [1 of 1] Compiling Main ( Bar.hs, Bar.o ) Bar.hs:2:61: parse error on input `return' }}} I don't know if this is a problem with TH pretty printer or if GHC is supposed to parse semicolons wherever they are.. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9022> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9386: GHCi cannot load .so in same ./
by GHC 11 Feb '16

11 Feb '16

#9386: GHCi cannot load .so in same ./ -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: GHCi crash Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- In my directory ./ I have an empty file Foo.hs and a shared object file mylib.so. From that directory in the shell, $ ghci Foo *.so GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading object (dynamic) mylib.so ... failed. <command line>: user specified .o/.so/.DLL could not be loaded (mylib.so: cannot open shared object file: No such file or directory) Whilst trying to load: (dynamic) mylib.so Additional directories searched: (none) It's interesting that GHCi searches ./ and identifies the correct object file, but then fails to load it. I have also tried the path ./*.so for the GHCi option. However, if I move mylib.so to a directory ./Temp, $ ghci Foo Temp/*.so loads without issue. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9386> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8136: arr020 test fails randomly with ghci way
by GHC 07 Feb '16

07 Feb '16

#8136: arr020 test fails randomly with ghci way -----------------------------+---------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.7 Keywords: | Operating System: Linux Architecture: x86 | Type of failure: Runtime crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -----------------------------+---------------------------------- I noticed that when I run arr020 (`make TEST=arr020`) it randomly segfaults when running `ghci` way. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8136> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8265: getTokenStream fails for source using cpp
by GHC 07 Feb '16

07 Feb '16

#8265: getTokenStream fails for source using cpp -----------------------------------+--------------------------------------- Reporter: alanz | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHC API | Version: 7.6.3 Keywords: | Operating System: Linux Architecture: | Type of failure: Compile-time crash Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- Calling getTokenStream (or getRichTokenStream) on a module that has CPP directives fails as the lexer is given un-preprocessed source -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8265> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8842: Make sure msys2 builds non emulating binaries
by GHC 06 Feb '16

06 Feb '16

#8842: Make sure msys2 builds non emulating binaries ------------------------------------+--------------------------------- Reporter: schyler | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.1-rc2 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+--------------------------------- I came across this in my own project. MSys2 doesn't enter #ifdef blocks which test for _WIN32. Instead, it pretends to be Linux and has a set of headers which emulate things like mmap. These emulation functions are really really slow -- in my personal tests about 10x slower than calling the WINAPI -- so this ticket is just a reminder (it may already be done) for someone to check that MSys2 builds things non-emulated in GHC. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8842> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9638: Speed up Data.Char.isDigit
by GHC 05 Feb '16

05 Feb '16

#9638: Speed up Data.Char.isDigit -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: Runtime hour) | performance bug Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- `isDigit` is currently defined like this: {{{#!hs isDigit :: Char -> Bool isDigit c = c >= '0' && c <= '9' }}} This will short-circuit the right way if you're looking for digits mixed with spaces, but the wrong way if you're looking for digits mixed with letters. It also requires a conditional jump to do that short-circuiting (confirmed by inspecting the assembly). It should be better to use an unsigned comparison instead: {{{#!hs isDigit :: Char -> Bool isDigit c = (fromIntegral (ord c) :: Word) - 48 <= 9 }}} The interesting section looks like this {{{ movq 7(%rbx),%rax addq $-48,%rax cmpq $9,%rax setbe %al movzbl %al,%eax shlq $3,%rax movq ghczmprim_GHCziTypes_Bool_closure_tbl(%rax),%rbx addq $8,%rbp jmp *(%rbp) }}} or like this with -fllvm: {{{ movq 7(%rbx), %rax addq $-48, %rax cmpq $10, %rax sbbq %rax, %rax andq $8, %rax movq ghczmprim_GHCziTypes_Bool_closure_tbl(%rax), %rbx movq 8(%rbp), %rax addq $8, %rbp jmpq *%rax # TAILCALL }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9638> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8746: Crosscompiling
by GHC 02 Feb '16

02 Feb '16

#8746: Crosscompiling -------------------------------------+------------------------------------- Reporter: Visionstar | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Keywords: Crosscompile | Operating System: Linux cross compile failed ncurses | Type of failure: Building GHC setupterm not found | failed Architecture: Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -------------------------------------+------------------------------------- Hello! I tried to crosscompile from linux i386 to arm-linux-gnueabihf, but i cant make it happen, because it gives me this weird error while running 'make': {{{ checking ncurses.h usability... yes checking ncurses.h presence... yes checking for ncurses.h... yes checking for setupterm in -ltinfo... no checking for setupterm in -lncursesw... no checking for setupterm in -lncurses... no checking for setupterm in -lcurses... no configure: error: in '/home/edi/ghc_cross/ghc/libraries/terminfo': configure: error: curses library not found, so this package cannot be built See 'config.log' for more details make[2]: *** [libraries/terminfo/dist-install/package-data.mk] Error 1 make[1]: *** [all_libraries/terminfo] Error 2 make[1]: Leave Directory '/home/edi/ghc_cross/ghc' make: *** [all] Error 2 }}} What have i done: -) Compiled 7.8.0 from github (The log says 'That should have been 7.8.0', i chose 7.8 because i thought it would be more stable for crosscompiling) to my i386 (normal boot, configure, make, make install). This worked fine -) installed newest llvm from svn (LLVM version 3.5svn) -) replaced the libffi-3.0.11.tar.gz in ghc/libffi-tarballs with libffi-3.0.13 -) added this version of mk/build.mk: {{{ SRC_HC_OPTS = -H32m _o -fasm -Rghc-timing GhcStage1HcOpts = -O -fasm GhcStage2HcOpts = -O0 -DDEBUG -Wall GhcLibHcOpts = -O -fasm -XGenerics GhcLibWays = v dyn SplitObjs = NO Stage1Only = YES }}} -) downloaded the sourcecode of ncurses from http://ftp.de.debian.org/debian/pool/main/n/ncurses/ncurses_5.9.orig.tar.gz and builded it with "./configure arm-linux-gnueabihf --with-gcc=arm-linux- gnueabihf-gcc --target=arm-linux-gnueabihf --prefix=/usr/arm-linux- gnueabihf " + "make". afterwards i added the folder to my $PATH -)did "perl boot", "./configure --target=arm-linux-gnueabihf --with-gcc =arm-linux-gnueabihf-gcc --prefix=/usr/arm-linux-gnueabihf" and "make". ./configure worked, but make gives me this weird error. I also tried copying all included files from ncurses to the libraries/terminfo folder, but that also didn't work. I think the mistake is somewhere in the building process, but i'm not exactly sure, so thats why i'm posting this bug. Does anyone have an idea about that? PS: i also made sure that i met the prerequirements mentioned in https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Linux and https://ghc.haskell.org/trac/ghc/wiki/Building/CrossCompiling Greetings, Edi -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8746> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9105: Profiling binary consumes CPU even when idle on Linux.
by GHC 27 Jan '16

27 Jan '16

#9105: Profiling binary consumes CPU even when idle on Linux. ----------------------------+--------------------------------- Reporter: robinp | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Linux Architecture: x86 | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------+--------------------------------- The program is main = forever $ threadDelay 1000000 >> return () . Compiled with 32bit GHC 7.6.3 or 7.8.2 on Debian (inside a VM), GHC 7.4.1 on Ubuntu (not VM). The non-profiling binary doesn't consume CPU, the profiling does ~10% (of a 2Ghz machine). Running with +RTS -I0, so this is not the idle gc. When strace-ing, the profiling one seems to receive a constant flow of SIGVTALRM, while the normal receives one burst each second. I see I can switch off "master tick interval" with -V0, and then CPU is not used, but the consequences of this are not very well documented (apart from context switching becoming deterministic). Interestingly, if I compile using profiling on Windows (latest haskell- platform, 64bit), it doesn't use more CPU than the non-profiling. So, the question is, why does this happen on Linux, and if it can be avoided somehow. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9105> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8287: exploring calling convention changes and related engineering for 7.10
by GHC 25 Jan '16

25 Jan '16

#8287: exploring calling convention changes and related engineering for 7.10 ------------------------------------+------------------------------------- Reporter: carter | Owner: Type: task | Status: new Priority: high | Milestone: 7.10.1 Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Rocket Science | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I'm creating this as a master ticket for systematically exploring and benchmarking (possibly breaking) changes to the GHC calling convention. This work will initially focus on x86/x86_64, but may have larger scope. Goals: 1. if possible, improve performance systematically for code run on recent CPU micro architecture generations (eg sandybridge, haswell, and future extensions like Knights Landing and Skylake), ideally without pessimizing code on other or older x86_64 micro-architectures 2. Try to bring native and llvm codegens closer to feature parity (or at the very least, do not widen their capability gap) 3. a few other pieces too, will amend this ticket as ideas / plans clarify -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8287> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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