- ghc-devs - Haskell.org

Re: [commit: packages/template-haskell] master: Make Pred a type synonym of Type (issue #7021) (57b662c)
by Johan Tibell 23 Mar '14

23 Mar '14

What's the right way to fix libraries (e.g. aeson) that break because classP was removed? On Mon, Feb 10, 2014 at 2:39 AM, <git(a)git.haskell.org> wrote: > Repository : ssh://git@git.haskell.org/template-haskell > > On branch : master > Link : > http://git.haskell.org/packages/template-haskell.git/commitdiff/57b662c3efd… > > >--------------------------------------------------------------- > > commit 57b662c3efd8579595c8642fce2d4cd60ba4ec0b > Author: YoEight <yo.eight(a)gmail.com> > Date: Fri Jan 10 21:42:01 2014 +0100 > > Make Pred a type synonym of Type (issue #7021) > > In order to make any type as a Predicate in Template Haskell, as > allowed by ConstraintKinds > > Signed-off-by: Richard Eisenberg <eir(a)cis.upenn.edu> > > > >--------------------------------------------------------------- > > 57b662c3efd8579595c8642fce2d4cd60ba4ec0b > Language/Haskell/TH.hs | 7 +++---- > Language/Haskell/TH/Lib.hs | 21 ++++++++------------- > Language/Haskell/TH/Ppr.hs | 8 ++------ > Language/Haskell/TH/Syntax.hs | 6 ++---- > 4 files changed, 15 insertions(+), 27 deletions(-) > > diff --git a/Language/Haskell/TH.hs b/Language/Haskell/TH.hs > index 2ab19bd..e9765a9 100644 > --- a/Language/Haskell/TH.hs > +++ b/Language/Haskell/TH.hs > @@ -68,7 +68,7 @@ module Language.Haskell.TH( > -- ** Patterns > Pat(..), FieldExp, FieldPat, > -- ** Types > - Type(..), TyVarBndr(..), TyLit(..), Kind, Cxt, Pred(..), > Syntax.Role(..), > + Type(..), TyVarBndr(..), TyLit(..), Kind, Cxt, Pred, > Syntax.Role(..), > > -- * Library functions > -- ** Abbreviations > @@ -105,14 +105,14 @@ module Language.Haskell.TH( > bindS, letS, noBindS, parS, > > -- *** Types > - forallT, varT, conT, appT, arrowT, listT, tupleT, sigT, litT, > + forallT, varT, conT, appT, arrowT, equalityT, listT, tupleT, sigT, > litT, > promotedT, promotedTupleT, promotedNilT, promotedConsT, > -- **** Type literals > numTyLit, strTyLit, > -- **** Strictness > isStrict, notStrict, strictType, varStrictType, > -- **** Class Contexts > - cxt, classP, equalP, normalC, recC, infixC, forallC, > + cxt, normalC, recC, infixC, forallC, > > -- *** Kinds > varK, conK, tupleK, arrowK, listK, appK, starK, constraintK, > @@ -146,4 +146,3 @@ module Language.Haskell.TH( > import Language.Haskell.TH.Syntax as Syntax > import Language.Haskell.TH.Lib > import Language.Haskell.TH.Ppr > - > diff --git a/Language/Haskell/TH/Lib.hs b/Language/Haskell/TH/Lib.hs > index b7a88d6..17e794b 100644 > --- a/Language/Haskell/TH/Lib.hs > +++ b/Language/Haskell/TH/Lib.hs > @@ -466,19 +466,6 @@ tySynEqn lhs rhs = > cxt :: [PredQ] -> CxtQ > cxt = sequence > > -classP :: Name -> [TypeQ] -> PredQ > -classP cla tys > - = do > - tys1 <- sequence tys > - return (ClassP cla tys1) > - > -equalP :: TypeQ -> TypeQ -> PredQ > -equalP tleft tright > - = do > - tleft1 <- tleft > - tright1 <- tright > - return (EqualP tleft1 tright1) > - > normalC :: Name -> [StrictTypeQ] -> ConQ > normalC con strtys = liftM (NormalC con) $ sequence strtys > > @@ -536,6 +523,14 @@ sigT t k > t' <- t > return $ SigT t' k > > +equalityT :: TypeQ -> TypeQ -> TypeQ > +equalityT tleft tright > + = do > + tleft1 <- tleft > + tright1 <- tright > + let typ = AppT (AppT EqualityT tleft1) tright1 > + return typ > + > promotedT :: Name -> TypeQ > promotedT = return . PromotedT > > diff --git a/Language/Haskell/TH/Ppr.hs b/Language/Haskell/TH/Ppr.hs > index 2023f3a..e237066 100644 > --- a/Language/Haskell/TH/Ppr.hs > +++ b/Language/Haskell/TH/Ppr.hs > @@ -496,6 +496,8 @@ instance Ppr Type where > > pprTyApp :: (Type, [Type]) -> Doc > pprTyApp (ArrowT, [arg1,arg2]) = sep [pprFunArgType arg1 <+> text "->", > ppr arg2] > +pprTyApp (EqualityT, [arg1, arg2]) = > + sep [pprFunArgType arg1 <+> text "~", ppr arg2] > pprTyApp (ListT, [arg]) = brackets (ppr arg) > pprTyApp (TupleT n, args) > | length args == n = parens (sep (punctuate comma (map ppr args))) > @@ -540,11 +542,6 @@ pprCxt [t] = ppr t <+> text "=>" > pprCxt ts = parens (sep $ punctuate comma $ map ppr ts) <+> text "=>" > > ------------------------------ > -instance Ppr Pred where > - ppr (ClassP cla tys) = ppr cla <+> sep (map pprParendType tys) > - ppr (EqualP ty1 ty2) = pprFunArgType ty1 <+> char '~' <+> pprFunArgType > ty2 > - > ------------------------------- > instance Ppr Range where > ppr = brackets . pprRange > where pprRange :: Range -> Doc > @@ -569,4 +566,3 @@ hashParens d = text "(# " <> d <> text " #)" > > quoteParens :: Doc -> Doc > quoteParens d = text "'(" <> d <> text ")" > - > diff --git a/Language/Haskell/TH/Syntax.hs b/Language/Haskell/TH/Syntax.hs > index 3606f9d..17bb065 100644 > --- a/Language/Haskell/TH/Syntax.hs > +++ b/Language/Haskell/TH/Syntax.hs > @@ -1346,9 +1346,7 @@ data AnnTarget = ModuleAnnotation > > type Cxt = [Pred] -- ^ @(Eq a, Ord b)@ > > -data Pred = ClassP Name [Type] -- ^ @Eq (Int, a)@ > - | EqualP Type Type -- ^ @F a ~ Bool@ > - deriving( Show, Eq, Data, Typeable ) > +type Pred = Type > > data Strict = IsStrict | NotStrict | Unpacked > deriving( Show, Eq, Data, Typeable ) > @@ -1373,6 +1371,7 @@ data Type = ForallT [TyVarBndr] Cxt Type -- ^ > @forall \<vars\>. \<ctxt\> -> \<t > | TupleT Int -- ^ @(,), (,,), etc.@ > | UnboxedTupleT Int -- ^ @(#,#), (#,,#), etc.@ > | ArrowT -- ^ @->@ > + | EqualityT -- ^ @~@ > | ListT -- ^ @[]@ > | PromotedTupleT Int -- ^ @'(), '(,), '(,,), etc.@ > | PromotedNilT -- ^ @'[]@ > @@ -1453,4 +1452,3 @@ cmpEq _ = False > thenCmp :: Ordering -> Ordering -> Ordering > thenCmp EQ o2 = o2 > thenCmp o1 _ = o1 > - > > _______________________________________________ > ghc-commits mailing list > ghc-commits(a)haskell.org > http://www.haskell.org/mailman/listinfo/ghc-commits >

5 7

ghc-7.8.1 RC2 ppc dyn linked executable segfaults
by Jens Petersen 23 Mar '14

23 Mar '14

> > http://www.haskell.org/ghc/dist/7.8.1-rc2/ >> >> > A test build on ppc completed but then the dyn executable sanity check > failed (not yet sure why): > http://ppc.koji.fedoraproject.org/koji/taskinfo?taskID=1707922 > The ppc64 build looks okay, but ppc seems to have a problem with executables dyn linked to Haskell libs segfaulting. Is anyone able to reproduce this on Linux/ppc (32bit)? Debian? I don't have access yet to a ppc box to investigate further but I see the segfault for "ghc -dynamic Hello.hs; ./Hello" on ppc in the fedora buildsys. http://ppc.koji.fedoraproject.org/kojifiles/work/tasks/1459/1711459/build.l…"ghc -v -dynamic Foo.hs") [1] I guess I should file a bug anyway. I sent a heads-up mail to Gustavo too. Jens [1] full log is http://ppc.koji.fedoraproject.org/kojifiles/work/tasks/1459/1711459/build.l…

2 4

HEADS-UP: new server-side validation git hook for submodule updates & call-for-help
by Herbert Valerio Riedel 23 Mar '14

23 Mar '14

Hello *, I've put in place a new server-side validation hook a few days ago, and since nobody seemed to have complained yet, I assume it didn't have any adverse effects so far :-) It will only be triggered when Git submodule references are touched by a commit; you can find some preliminary (but incomplete) documentation and a sample session triggering validation-failure on purpose at https://ghc.haskell.org/trac/ghc/ticket/8251#comment:4 (this will be turned into a proper wiki-page once #8251 is completed; there's some minor details wrt some corner cases that still need to be looked at) So, this mostly addresses the server-side requirements for migrating to a proper git-submodule set-up for ghc.git; The next steps, however, include taking care of the client-side work-flow for working with a fully "submoduled" ghc.git setup. Personally, I'm quite comfortable using direct git commands to manage such a construct, but I'm well aware not everyone is (as previous discussions here have shown). Also, as my time is rather limited, I'd like to ask interested parties to join in and help formulate the future client-side work-flow[1] and/or update (or rewrite) the 'sync-all' to provide a seamless or at least smooth transition for those GHC devs who want to keep using "sync-all" instead of using direct Git commands. [1]: There's some difference in how tracked upstream packages and GHC-HQ owned sub-repos are to be handled workflow-wise, to avoid ending up with a noisy ghc.git history. For instance, having ghc.git with submodules is not the same as having a huge monolithic ghc.git repository with all subrepos embedded. specifically, it might not be sensible to propagate *every* single subrepo-commit as a separate ghc.git submod-ref update, but rather in logical batches (N.B.: using submodules gives the additional ability to git bisect within subrepos instead of having to bisect always only at top-level). This is one example of things to discuss/consider when designing the new work-flow. Cheers, hvr

5 6

Was GHC 7.8 RC2 profiled-compiled?
by Alfredo Di Napoli 21 Mar '14

21 Mar '14

Evening guys, was GHC 7.8 RC2 released with profiling enabled? Trying to use TH yields: You can't use Template Haskell with a profiled compiler This message is spit out from ghc mod. Do you guys know if the plan was releasing the RC2 profile compiled or is just a flag forgotten to be disabled? Furthermore, do you know if is available a non-profiled version available for Mavericks ? Sorry if I'm just being stupid! Alfredo

1 1

Haddock strings in .hi files
by Mateusz Kowalczyk 21 Mar '14

21 Mar '14

Hi all, I saw https://ghc.haskell.org/trac/ghc/ticket/5467 pop up in my inbox and it reminded me of something I've been wondering for a while: why do we not store Haddock docstrings in the interface file? I think that if we did, we could do some great things: 1. Show docs in GHCi (I vaguely recall someone working on this ~1 year ago, does anyone have any info?) 2. Allow Haddock to work a lot faster: the big majority of time spent when creating documentation is actually spent by Haddock calling various GHC functions, such as type-checking the modules. Only a small amount of time is actually spent by Haddock on other tasks such as parsing or outputting the documentation. If we could simply get everything we need from the .hi files, we save ourselves a lot of time. 3. Allow Haddock to create partial documentation: a complaint I sometimes hear is if anything at all in the project doesn't type check, we don't get any documentation at all. I think that it'd be viable to generate only the documentation for the modules/functions that do type-check and perhaps skip type signatures for everything else. Points 1. and 2. are of clear benefit. Point 3. is a simple afterthought and thinking about it some more, I think that maybe it'd be possible to do this with what we have right now: is type-checking separate parts of the module supported? Can we retrieve documentation for the parts that don't type-check? I am asking for input on what people think. I am not familiar at all with what goes into the .hi file (and I can't find anything concrete! Am I missing some wiki page?) at all and why. At the very least, 1. should be easy to implement. It was suggested that I submit a proposal for this as part of GSoC, namely implementing 1. and 2.. I admit that having much faster documentation builds would be amazing and Edward K. and Carter S. seem to think that this is very do-able in the 3 month period that GSoC runs over. While I say all this, I have already submitted my proposal on a different topic. I am considering writing this up and submitting this as well but I am looking for some insight into the problem first. If there are any students around still looking for ideas, please do speak up if you want to snatch this. If there are people that are eager to mentor something like this then I suppose they should speak up too. Thanks! -- Mateusz K.

6 12

Possible refactoring for __stg_gc_fun in HeapStackCheck.cmm
by Horsng Junn 20 Mar '14

20 Mar '14

Hi list! This is my first mail to the list; please correct me if I made any mistakes. I’ve been studying GHC source code for studying’s sake, and think I’ve found a few problems in this function. Below comes the function in its current form: ———————————————————— __stg_gc_fun /* explicit stack */ { W_ size; W_ info; W_ type; info = %GET_FUN_INFO(UNTAG(R1)); // cache the size type = TO_W_(StgFunInfoExtra_fun_type(info)); if (type == ARG_GEN) { size = BITMAP_SIZE(StgFunInfoExtra_bitmap(info)); } else { if (type == ARG_GEN_BIG) { #ifdef TABLES_NEXT_TO_CODE // bitmap field holds an offset size = StgLargeBitmap_size( StgFunInfoExtra_bitmap(info) + %GET_ENTRY(UNTAG(R1)) /* ### */ ); #else size = StgLargeBitmap_size( StgFunInfoExtra_bitmap(info) ); #endif } else { size = BITMAP_SIZE(W_[stg_arg_bitmaps + WDS(type)]); } } #ifdef NO_ARG_REGS // we don't have to save any registers away Sp_adj(-3); Sp(2) = R1; Sp(1) = size; Sp(0) = stg_gc_fun_info; jump stg_gc_noregs []; #else W_ type; type = TO_W_(StgFunInfoExtra_fun_type(info)); // cache the size if (type == ARG_GEN || type == ARG_GEN_BIG) { // regs already saved by the heap check code Sp_adj(-3); Sp(2) = R1; Sp(1) = size; Sp(0) = stg_gc_fun_info; // DEBUG_ONLY(foreign "C" debugBelch("stg_fun_gc_gen(ARG_GEN)");); jump stg_gc_noregs []; } else { jump W_[stg_stack_save_entries + WDS(type)] [*]; // all regs live // jumps to stg_gc_noregs after saving stuff } #endif /* !NO_ARG_REGS */ } The problems I see: 1. “type” variable is declared and its value calculated twice, 2. if (type == ARG_GEN … check is needlessly done twice, 3. “size" value is calculated and then discarded in !NO_ARG_REGS, for types other than ARG_GEN or ARG_GEN_BIG, and 4. (this is a minor one) Sp_adj(-3) ~ jmup_stg_gc_noregs code is duplicated. I know they’re in separate #if branch but still... And my proposed fixes are: ———————————————————— __stg_gc_fun /* explicit stack */ { W_ size; W_ info; W_ type; info = %GET_FUN_INFO(UNTAG(R1)); // cache the size type = TO_W_(StgFunInfoExtra_fun_type(info)); if (type == ARG_GEN) { // regs already saved by the heap check code size = BITMAP_SIZE(StgFunInfoExtra_bitmap(info)); } else { if (type == ARG_GEN_BIG) { // regs already saved by the heap check code #ifdef TABLES_NEXT_TO_CODE // bitmap field holds an offset size = StgLargeBitmap_size( StgFunInfoExtra_bitmap(info) + %GET_ENTRY(UNTAG(R1)) /* ### */ ); #else size = StgLargeBitmap_size( StgFunInfoExtra_bitmap(info) ); #endif } else { #ifdef NO_ARG_REGS // we don't have to save any registers away size = BITMAP_SIZE(W_[stg_arg_bitmaps + WDS(type)]); #else jump W_[stg_stack_save_entries + WDS(type)] [*]; // all regs live // jumps to stg_gc_noregs after saving stuff #endif } } Sp_adj(-3); Sp(2) = R1; Sp(1) = size; Sp(0) = stg_gc_fun_info; jump stg_gc_noregs []; } What do you guys think? Thanks, Horsng Junn

2 2

Pretty printing
by Simon Peyton Jones 19 Mar '14

19 Mar '14

Gergo I'm a bit out of date... did you update those test results etc to get to clean validate? S

3 2

"quick" vs "perf" builds
by Johan Tibell 19 Mar '14

19 Mar '14

Hi, In my mind the "quick" build should be like the "perf" build, except building the stage2 compiler should be much faster. However, the perf build uses GhcLibHcOpts = -O2 while the quick build uses GhcLibHcOpts = -O -fasm This means that if you're working on optimizing the generated code and are running benchmarks to verify your results, the quick build doesn't do the right thing. Since the purpose of the quick build is to work on the stage2 compiler, would it make sense having it build the libraries in the same way as the perf build? -- Johan

4 5

Re: We need to add role annotations for 7.8
by David Terei 19 Mar '14

19 Mar '14

Adding in GHC-DEV. Yes, sorry for no contact, my GHC email filter was misconfigured so only got alerted when SPJ emailed me directly a few days back. On 18 March 2014 17:36, David Mazieres expires 2014-06-16 PDT <mazieres-i58umkudjfnfpfdx6jbbn3ymzi(a)temporary-address.scs.stanford.edu> wrote: > At Fri, 14 Mar 2014 18:45:16 +0100, > Mikhail Glushenkov wrote: >> >> Hi Richard, >> >> > The real trouble with making this decision is that we have no real >> > guidance. We've tried contacting David Terei (the originator of >> > Safe Haskell) several times to no avail. If you are an actual >> > consumer of Safe Haskell and would like to share your opinion on >> > this front, I do encourage you to make a ticket, essentially >> > requesting a resurrection of the extra Safe checks. >> >> Yes, it would be nice if David Terei or David Mazières (CC:ed) could comment. > > Sadly, it appears some mail may not have made it through to David > Terei's mailbox. > > At any rate, David and I just discussed the new Coerce typeclass. > Based on David's understanding of its behavior, it sounds pretty > dangerous for Safe Haskell. At a minimum, the programmer is going to > need to understand a lot more than Haskell 2010 to write secure code. > > Based on my possibly limited understanding of the new > feature--automatically generating instances of the Coerce type seems > very un-Haskell-like. By analogy, we could automatically generate > instance of Read and Show (or add equivalent DebugRead/DebugShow > classes) wherever possible, but this would similarly break abstraction > by providing effective access to non-exported constructors. > > I understand why there is a need for something better than > GeneralizedNewtypeDeriving. However, implementing Coerce as a > typeclass has the very serious disadvantage that there is no Haskell > mechanism for controlling instance exports. And if we are going to > add a new mechanism (roles) to control such exports, exporting an > instance that is never requested and that undermines modularity and > abstraction is an unfortunate default. > > It may be too late for this, but a cleaner solution more in keeping > with other extensions would be to have a -XDeriveCoerce extension that > allows Coerce to be explicitly derived when safe. This could be > combined with leaving the previous behavior of > GeneralizedNewtypeDeriving and just deprecating the language feature. > > Though controlling instance exports does not have a precedent, another > option might be to special-case the Coerce class and only export > instances of Coerce when all constructors of a type are also exported. > This would prevent anyone from using Coerce to do things they couldn't > already do manually. > > David >

1 0

Re: [commit: ghc] ghc-parmake-gsoc: Implement the parallel upsweep (#910) (8d9edfe)
by Johan Tibell 17 Mar '14

17 Mar '14

I just had reason to have a look at this code. I just want to say thanks for writing such nice, readable code. I wish all code in GHC had nicely written Haddock like these. Would make GHC hacking a bit more approachable. On Tue, Aug 27, 2013 at 4:11 PM, <git(a)git.haskell.org> wrote: > Repository : ssh://git@git.haskell.org/ghc > > On branch : ghc-parmake-gsoc > Link : > http://ghc.haskell.org/trac/ghc/changeset/8d9edfed74e8fd03933d4e3540f6372c2… > > >--------------------------------------------------------------- > > commit 8d9edfed74e8fd03933d4e3540f6372c269de538 > Author: Patrick Palka <patrick(a)parcs.ath.cx> > Date: Wed Aug 21 16:55:52 2013 -0400 > > Implement the parallel upsweep (#910) > > The parallel upsweep is the parallel counterpart to the default > sequential upsweep. It attempts to compile modules in parallel by > subdividing the work of the upsweep into parts that can be executed > concurrently by multiple Haskell threads. > > In order to enable the parallel upsweep, the user has to pass the -jN > flag to GHC, where N is an optional number denoting the number of jobs, > or modules, to compile in parallel, like with GNU make. In GHC this > just > sets the number of capabilities to N. > > > >--------------------------------------------------------------- > > 8d9edfed74e8fd03933d4e3540f6372c269de538 > compiler/main/DynFlags.hs | 8 + > compiler/main/GhcMake.hs | 354 > ++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 359 insertions(+), 3 deletions(-) > > Diff suppressed because of size. To see it, use: > > git diff-tree --root --patch-with-stat --no-color --find-copies-harder > --ignore-space-at-eol --cc 8d9edfed74e8fd03933d4e3540f6372c269de538 > > _______________________________________________ > ghc-commits mailing list > ghc-commits(a)haskell.org > http://www.haskell.org/mailman/listinfo/ghc-commits >

1 0