March 2014 - ghc-devs

Arrow notation vs RebindableSyntax
by Nicolas Frisby 15 Mar '14

15 Mar '14

The 7.8-rc2 User Guide for rebindable syntax includes: Arrow notation (see Section 7.16, "Arrow notation ") uses whatever arr, > (>>>), first, app, (|||) and loop functions are in scope. But unlike the > other constructs, the types of these functions must match the Prelude types > very closely. Details are in flux; if you want to use this, ask! I want to use this: my types for the functions apparently do not match the Prelude types closely enough. Whom should I ask about this? Thanks very much. -Nick ----- Further Context If I do something similar with Monad and RebindableSyntax, it type-checks. I'm doing some experimentation for work. I'd like to index my arrows as follows. (Disclaimer: I have not yet considered any of the laws; I do not currently intend to support `app' and |||.) infixr 1 >>>, <<< type family (:*:) (i :: Maybe *) (j :: Maybe *) :: Maybe * type instance Nothing :*: j = j type instance i :*: Nothing = i type instance Just i :*: Just j = Just (i,j) returnA :: IArrow arr => arr Nothing a a returnA = arr id -- second, ***, and &&& can have the standard default definitions class IArrow (arr :: Maybe * -> * -> * -> *) where arr :: (b -> c) -> arr Nothing b c (>>>) :: arr i a b -> arr j b c -> arr (i :*: j) a c first :: arr i b c -> arr i (b,d) (c,d) Unfortunately, the following does not type-check with -XArrows and -XRebindableSyntax. diagram :: IArrow arr => arr f x fx -> arr g x gx -> arr (f :*: g) x gx diagram f g = proc x -> do fx <- f -< x gx <- g -< x returnA -< gx The error messages indicate that the type-checker is attempting to unify the types of f, g, returnA, and the entire proc block. However, the copy-and-pasted desugaring of that code *does* type-check (mutatis mutandi). This S data type is an example of an IArrow. data S i a b where SN :: ( a -> b ) -> S Nothing a b SJ :: s -> ((a,s) -> (b,s)) -> S (Just s) a b In terms of the S type, the objective of IArrow is to allow each "box in the diagram" to have its own state.

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testing ghc-7.8 rc2: linker issues
by Matthias Fischmann 14 Mar '14

14 Mar '14

hi, this time i am running 7.8 rc2 (binary for x64 on debian testing). after a successful '/usr/bin/cabal install cabal-install', i am running into different instances of this: | [...] | [25 of 25] Compiling Text.ParserCombinators.Parsec.Perm ( Text/ParserCombinators/Parsec/Perm.hs, dist/build/Text/ParserCombinators/Parsec/Perm.o ) | /usr/bin/ld: cannot find -lHSmtl-2.1.2-ghc7.8.0.20140228 | collect2: error: ld returned 1 exit status | Failed to install parsec-3.1.5 | cabal: Error: some packages failed to install: | network-2.4.2.2 depends on parsec-3.1.5 which failed to install. | parsec-3.1.5 failed during the building phase. The exception was: | ExitFailure 1 what makes me suspect this could be relevant to this list is that the symptoms are weirdly sporadic. my story: 1. cabal install string-conversions fails because -lHStext-1.1.0.1 cannot be found. 2. ghc-pkg unregister <a few packages> 3. cabal install network (which pulls text) => fails (see above) 4. cabal install string-conversions => works! i will read up on dynamic linking in ghc now. cheers, matthias

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haddock issue building ghc-7.8 from git
by Matthias Fischmann 14 Mar '14

14 Mar '14

Hi, When building from git (branch ghc-7.8 as of today), I run into a haddock issue because __GLASGOW_HASKELL__ appearently is not 709 on my system. Not sure whether this is a bug, and if it should go to trac/haddock or trac/ghc, so I decided to post it here. My "fix" is easy enough (even though I ran into other problems later, so I don't really know how well it works): | ~/src/ghc/utils/haddock/src/Haddock$ git diff | diff --git a/src/Haddock/InterfaceFile.hs b/src/Haddock/InterfaceFile.hs | index 924829d..19a742f 100644 | --- a/src/Haddock/InterfaceFile.hs | +++ b/src/Haddock/InterfaceFile.hs | @@ -76,14 +76,14 @@ binaryInterfaceMagic = 0xD0Cface | -- (2) set `binaryInterfaceVersionCompatibility` to [binaryInterfaceVersion] | -- | binaryInterfaceVersion :: Word16 | -#if __GLASGOW_HASKELL__ == 709 | +-- #if __GLASGOW_HASKELL__ == 709 | binaryInterfaceVersion = 25 | | binaryInterfaceVersionCompatibility :: [Word16] | binaryInterfaceVersionCompatibility = [binaryInterfaceVersion] | -#else | -#error Unsupported GHC version | -#endif | +-- #else | +-- #error Unsupported GHC version | +-- #endif | | | initBinMemSize :: Int thanks, matthias

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Where to find GHC.Types.D#_con_info
by Karel Gardas 14 Mar '14

14 Mar '14

Hello, I'm trying to debug few issues in SPARC NCG, now dealing with double floats issue. Always get 0.0 and while hunting this I've stepped over GHC.Types.D#_con_info which I'm not able to find in GHC sources but I guess it should be somewhere... Any idea where to look to see its code for reference? Thanks! Karel

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New validate failures
by Johan Tibell 14 Mar '14

14 Mar '14

Hi, Did something change in pretty-printing recently? I saw these new validate failures today: Unexpected failures: ghci.debugger/scripts break008 [bad stdout] (ghci) ghci.debugger/scripts break012 [bad stdout] (ghci) ghci.debugger/scripts break026 [bad stdout] (ghci) ghci.debugger/scripts hist001 [bad stdout] (ghci) ghci/scripts T5545 [bad stdout] (ghci) ghci/scripts ghci008 [bad stdout] (ghci) ghci/scripts ghci012 [bad stdout] (ghci) ghci/scripts ghci023 [bad stdout] (ghci) ghci/scripts ghci025 [bad stdout] (ghci) ghci/scripts ghci026 [bad stdout] (ghci) ghci/scripts ghci055 [bad stdout] (ghci) Two example stdout changes: --- ./T5545.stdout 2014-03-13 09:48:23.000000000 +0100 +++ ./T5545.run.stdout 2014-03-13 21:11:32.000000000 +0100 @@ -1,2 +1,2 @@ -($!) :: (a -> b) -> a -> b -- Defined in 'Prelude' +$! :: forall a b. (a -> b) -> a -> b -- Defined in 'Prelude' infixr 0 $! *** unexpected failure for T5545(ghci) --- ./ghci008.stdout 2014-03-13 09:48:23.000000000 +0100 +++ ./ghci008.run.stdout 2014-03-13 21:12:20.000000000 +0100 @@ -32,5 +32,5 @@ -- Defined in 'GHC.Float' instance RealFloat Float -- Defined in 'GHC.Float' instance RealFloat Double -- Defined in 'GHC.Float' -Data.List.isPrefixOf :: Eq a => [a] -> [a] -> Bool +isPrefixOf :: forall a. Eq a -> [a] -> [a] -> Bool -- Defined in 'Data.List' *** unexpected failure for ghci008(ghci)

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Should we always inline newByteArray#?
by Johan Tibell 13 Mar '14

13 Mar '14

Hi all, After some refactoring of the StgCmmPrim, it's now possible to have both an inline and an out-of-line (in PrimOps.cmm) version of the same primop. Very soon (#8876) we'll have both an inline and an out-of-line version of newByteArray#. The inline version is used when the array size is statically known and commons up the allocation with the normal heap check. The reason to have both versions is that we don't want to increase code size to much (by inlining a primop which implementation is large) unless we know that there's a benefit in doing so. However, the newByteArray# implementation is one function call (to allocate) followed by three stores (to the closure header). Perhaps, that's small enough to always inline? It would save one function call for each call to newByteArray#. Anyone have any thoughts on whether always inlining would be a good idea? -- Johan

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[PATCH] sync-all: Skip END actions on exceptions
by Florian Weimer 13 Mar '14

13 Mar '14

The instructions at <https://ghc.haskell.org/trac/ghc/wiki/Newcomers> were slightly outdated, and result in a rather confusing error messsage: $ ./sync-all --testsuite get Unrecognised flag: --testsuite at ./sync-all line 872. == Checking for old haddock repo == Checking for old binary repo == Checking for old mtl repo == Checking for old Cabal repo == Checking for old time from tarball ============================ ATTENTION! You have an old time package in your GHC tree! Please remove it (e.g. "rm -r libraries/time"), and then run "./sync-all get" to get the new repository. ============================ == Checking for obsolete Git repo URL $ The patch corrects the error message. I've removed the --testsuite flag from the wiki page as well.

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Building GHC on Windows
by Jan Stolarek 13 Mar '14

13 Mar '14

I'm trying to build GHC on 64-bit Windows 7. I installed Cygwin, GHC and cloned the main repo but when I run configure I get this error: configure: Building in-tree ghc-pwd checking for path to top of build tree... cygwin warning: MS-DOS style path detected: C:/cygwin64/home/tewi/head Preferred POSIX equivalent is: /home/tewi/head CYGWIN environment variable option "nodosfilewarning" turns off this warning. Consult the user's guide for more details about POSIX paths: http://cygwin.com/cygwin-ug-net/using.html#using-pathnames C:/cygwin64/home/tewi/head checking for gcc... C:/cygwin64/home/tewi/head/inplace/mingw/bin/gcc.exe checking whether the C compiler works... no configure: error: in `/home/tewi/head': configure: error: C compiler cannot create executables See `config.log' for more details I have gcc installed under Cygwin, but for some reason ./configure is looking for an in-tree compiler. I tried passing --with-gcc=/usr/bin/gcc to configure but with no result. Help? Janek

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Can't build HEAD on OS X
by Johan Tibell 13 Mar '14

13 Mar '14

Checking out a clean tree today (commit: ) I can no longer build HEAD. Here's what I did: git clone git://git.haskell.org/ghc.git cd ghc ./sync-all --no-dph get cp mk/build.mk.sample mk/build.mk # Uncomment devel2 in mk/build.mk ./boot && ./configure --with-gcc=/usr/local/bin/gcc-4.9 make Here's the result: gcc -E -m64 -DPROFILING -DTHREADED_RTS -DDEBUG -Irts/dist/build -m64 -fno-stack-protector -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Winline -Waggregate-return -Wpointer-arith -Wmissing-noreturn -Wnested-externs -Wredundant-decls -Iincludes -Iincludes/dist -Iincludes/dist-derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -fno-strict-aliasing -fno-common -DDTRACE -O2 -fomit-frame-pointer -DRtsWay=\"rts_v\" -Wno-strict-prototypes -Wno-inline -finline-limit=2500 -MM -x c rts/sm/Compact.c -MF rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit clang: error: unknown argument: '-finline-limit=2500' [-Wunused-command-line-argument-hard-error-in-future] clang: note: this will be a hard error (cannot be downgraded to a warning) in the future make[1]: *** [rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm] Error 1 More context: sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.l_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.debug_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_debug_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_l_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.debug_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_debug_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.l_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_l_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && true gcc -E -m64 -DPROFILING -DTHREADED_RTS -DDEBUG -Irts/dist/build -m64 -fno-stack-protector -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Winline -Waggregate-return -Wpointer-arith -Wmissing-noreturn -Wnested-externs -Wredundant-decls -Iincludes -Iincludes/dist -Iincludes/dist-derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -fno-strict-aliasing -fno-common -DDTRACE -O2 -fomit-frame-pointer -DRtsWay=\"rts_v\" -Wno-strict-prototypes -Wno-inline -finline-limit=2500 -MM -x c rts/sm/Compact.c -MF rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit clang: error: unknown argument: '-finline-limit=2500' [-Wunused-command-line-argument-hard-error-in-future] clang: note: this will be a hard error (cannot be downgraded to a warning) in the future make[1]: *** [rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm] Error 1 make: *** [all] Error 2 -- Johan

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GHC 7.8 release
by Simon Peyton Jones 12 Mar '14

12 Mar '14

Friends The status of the GHC 7.8 release is here https://ghc.haskell.org/trac/ghc/wiki/Status/GHC-7.8/RC2. Alas we are currently stalled on #8870, #8834: we are getting seg-faults on Windows. (For example, on my laptop, the stage2 compiler seg-faults when compiling some (but not all) files. Although few people develop GHC on Windows, many people *use* GHC on Windows, so we can't really release in this state. We need help! Austin is trying, but it's all working on his Windows build. He's trying to get more machines to see if he can reproduce the failure there. Does anyone feel able to help? Even git-bisecting to find the offending commit would be a huge help. In principle I can do that (at two hours per bisection) but I was defeated by an out-of-sync Haddock. I need to know how to remove Haddock from the build altogether. But others are far more skilled than me. On #8834 Simon M speculates that we may have the callee-saves register wrong on Win64. Does anyone feel up to looking into that? Until we find what's going on, 7.8 is stalled. Thanks! Simon

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