1. 01 Oct, 2013 1 commit
  2. 11 Sep, 2013 1 commit
  3. 03 Sep, 2013 1 commit
    • Simon Peyton Jones's avatar
      Improve Linting in GHCi (fixes Trac #8215) · dfa8ef03
      Simon Peyton Jones authored
      The original problem was that we weren't bringing varaibles bound in the
      interactive context into scope before Linting the result of a top-level
      declaration in GHCi.  (We were doing this for expressions.)
      Moreover I found that we weren't Linting the result of desugaring
      a GHCi expression, which we really should be doing.
      It took me a bit of time to unravel all this, and I did some refactoring
      to make it easier next time.
        * CoreMonad contains the Lint wrappers that get the right
          environments into place.  It always had endPass and lintPassResult
          (which Lints bindings), but now it has lintInteractiveExpr.
        * Both use a common function CoreMonad.interactiveInScope to find
          those in-scope variables.
      Quite a bit of knock-on effects from this, but nothing exciting.
  4. 29 Aug, 2013 1 commit
  5. 27 Aug, 2013 1 commit
  6. 21 Jun, 2013 1 commit
    • eir@cis.upenn.edu's avatar
      Revise implementation of overlapping type family instances. · 569b2652
      eir@cis.upenn.edu authored
      This commit changes the syntax and story around overlapping type
      family instances. Before, we had "unbranched" instances and
      "branched" instances. Now, we have closed type families and
      open ones.
      The behavior of open families is completely unchanged. In particular,
      coincident overlap of open type family instances still works, despite
      emails to the contrary.
      A closed type family is declared like this:
      > type family F a where
      >   F Int = Bool
      >   F a   = Char
      The equations are tried in order, from top to bottom, subject to
      certain constraints, as described in the user manual. It is not
      allowed to declare an instance of a closed family.
  7. 30 May, 2013 1 commit
    • Simon Peyton Jones's avatar
      Make 'SPECIALISE instance' work again · 1ed04090
      Simon Peyton Jones authored
      This is a long-standing regression (Trac #7797), which meant that in
      particular the Eq [Char] instance does not get specialised.
      (The *methods* do, but the dictionary itself doesn't.)  So when you
      call a function
           f :: Eq a => blah
      on a string type (ie a=[Char]), 7.6 passes a dictionary of un-specialised
      This only matters when calling an overloaded function from a
      specialised context, but that does matter in some programs.  I
      remember (though I cannot find the details) that Nick Frisby discovered
      this to be the source of some pretty solid performanc regresisons.
      Anyway it works now. The key change is that a DFunUnfolding now takes
      a form that is both simpler than before (the DFunArg type is eliminated)
      and more general:
      data Unfolding
        = ...
        | DFunUnfolding {     -- The Unfolding of a DFunId
          			-- See Note [DFun unfoldings]
            		  	--     df = /\a1..am. \d1..dn. MkD t1 .. tk
                              --                                 (op1 a1..am d1..dn)
           		      	--     	    	      	       	   (op2 a1..am d1..dn)
              df_bndrs :: [Var],      -- The bound variables [a1..m],[d1..dn]
              df_con   :: DataCon,    -- The dictionary data constructor (never a newtype datacon)
              df_args  :: [CoreExpr]  -- Args of the data con: types, superclasses and methods,
          }                           -- in positional order
      That in turn allowed me to re-enable the DFunUnfolding specialisation in
      DsBinds.  Lots of details here in TcInstDcls:
      	  Note [SPECIALISE instance pragmas]
      I also did some refactoring, in particular to pass the InScopeSet to
      exprIsConApp_maybe (which in turn means it has to go to a RuleFun).
      NB: Interface file format has changed!
  8. 25 May, 2013 1 commit
  9. 20 May, 2013 1 commit
  10. 19 May, 2013 1 commit
    • ian@well-typed.com's avatar
      Fix a build problem with integer-simple · fdd552e0
      ian@well-typed.com authored
      We were trying to look up the mkInteger Id before we'd compiled
      the Integer modules. I'm not sure why this never showed up with
      integer-gmp; possibly we just always got lucky with the build
  11. 14 May, 2013 1 commit
    • ian@well-typed.com's avatar
      Fix the GHC package DLL-splitting · 60b86b04
      ian@well-typed.com authored
      There's now an internal -dll-split flag, which we use to tell GHC how
      the GHC package is split into 2 separate DLLs. This is used by
      Packages.isDllName to determine whether a call is within the same
      DLL, or whether it is a call to another DLL.
  12. 15 Feb, 2013 1 commit
  13. 04 Feb, 2013 1 commit
    • chak@cse.unsw.edu.au.'s avatar
      Fix tidying of vectorised code · 82a30378
      chak@cse.unsw.edu.au. authored
      * We need to keep the vectorised version of a variable alive while the original is alive.
      * This implies that the vectorised version needs to get into the iface if the original appears in an unfolding.
  14. 30 Jan, 2013 1 commit
  15. 28 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Pure refactoring · f1fa6eb2
      Simon Peyton Jones authored
      * Move tidyType and friends from TcType to TypeRep
        (It was always wrong to have it in TcType.)
      * Move mkCoAxBranch and friends from FamInst to Coercion
      * Move pprCoAxBranch and friends from FamInstEnv to Coercion
      No change in functionality, though there might be a little
      wibble in error message output, because I combined two different
      functions both called pprCoAxBranch!
  16. 21 Jan, 2013 1 commit
  17. 17 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Major patch to implement the new Demand Analyser · 0831a12e
      Simon Peyton Jones authored
      This patch is the result of Ilya Sergey's internship at MSR.  It
      constitutes a thorough overhaul and simplification of the demand
      analyser.  It makes a solid foundation on which we can now build.
      Main changes are
      * Instead of having one combined type for Demand, a Demand is
         now a pair (JointDmd) of
            - a StrDmd and
            - an AbsDmd.
         This allows strictness and absence to be though about quite
         orthogonally, and greatly reduces brain melt-down.
      * Similarly in the DmdResult type, it's a pair of
           - a PureResult (indicating only divergence/non-divergence)
           - a CPRResult (which deals only with the CPR property
      * In IdInfo, the
          strictnessInfo field contains a StrictSig, not a Maybe StrictSig
          demandInfo     field contains a Demand, not a Maybe Demand
        We don't need Nothing (to indicate no strictness/demand info)
        any more; topSig/topDmd will do.
      * Remove "boxity" analysis entirely.  This was an attempt to
        avoid "reboxing", but it added complexity, is extremely
        ad-hoc, and makes very little difference in practice.
      * Remove the "unboxing strategy" computation. This was an an
        attempt to ensure that a worker didn't get zillions of
        arguments by unboxing big tuples.  But in fact removing it
        DRAMATICALLY reduces allocation in an inner loop of the
        I/O library (where the threshold argument-count had been
        set just too low).  It's exceptional to have a zillion arguments
        and I don't think it's worth the complexity, especially since
        it turned out to have a serious performance hit.
      * Remove quite a bit of ad-hoc cruft
      * Move worthSplittingFun, worthSplittingThunk from WorkWrap to
        Demand. This allows JointDmd to be fully abstract, examined
        only inside Demand.
      Everything else really follows from these changes.
      All of this is really just refactoring, so we don't expect
      big performance changes, but acutally the numbers look quite
      good.  Here is a full nofib run with some highlights identified:
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
               expert          -2.6%    -15.5%      0.00      0.00     +0.0%
                fluid          -2.4%     -7.1%      0.01      0.01     +0.0%
                   gg          -2.5%    -28.9%      0.02      0.02    -33.3%
            integrate          -2.6%     +3.2%     +2.6%     +2.6%     +0.0%
              mandel2          -2.6%     +4.2%      0.01      0.01     +0.0%
             nucleic2          -2.0%    -16.3%      0.11      0.11     +0.0%
                 para          -2.6%    -20.0%    -11.8%    -11.7%     +0.0%
               parser          -2.5%    -17.9%      0.05      0.05     +0.0%
               prolog          -2.6%    -13.0%      0.00      0.00     +0.0%
               puzzle          -2.6%     +2.2%     +0.8%     +0.8%     +0.0%
              sorting          -2.6%    -35.9%      0.00      0.00     +0.0%
             treejoin          -2.6%    -52.2%     -9.8%     -9.9%     +0.0%
                  Min          -2.7%    -52.2%    -11.8%    -11.7%    -33.3%
                  Max          -1.8%     +4.2%    +10.5%    +10.5%     +7.7%
       Geometric Mean          -2.5%     -2.8%     -0.4%     -0.5%     -0.4%
      Things to note
      * Binary sizes are smaller. I don't know why, but it's good.
      * Allocation is sometiemes a *lot* smaller. I believe that all the big numbers
        (I checked treejoin, gg, sorting) arise from one place, namely a function
        GHC.IO.Encoding.UTF8.utf8_decode, which is strict in two Buffers both of
        which have several arugments.  Not w/w'ing both arguments (which is what
        we did before) has a big effect.  So the big win in actually somewhat
        accidental, gained by removing the "unboxing strategy" code.
      * A couple of benchmarks allocate slightly more.  This turns out
        to be due to reboxing (integrate).  But the biggest increase is
        mandel2, and *that* turned out also to be a somewhat accidental
        loss of CSE, and pointed the way to doing better CSE: see Trac
      * Runtimes are never very reliable, but seem to improve very slightly.
      All in all, a good piece of work.  Thank you Ilya!
  18. 01 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Refactor the invariants for ClsInsts · 5efe9b11
      Simon Peyton Jones authored
      We now have the invariant for a ClsInst that the is_tvs field
      is always completely fresh type variables. See
      Note [Template tyvars are fresh] in InstEnv.
      (Previously we frehened them when extending the instance environment,
      but that seems messier because it was an invariant only when the
      ClsInst was in an InstEnv.  Moreover, there was an invariant that
      thet tyvars of the DFunid in the ClsInst had to match, and I have
      removed that invariant altogether; there is no need for it.)
      Other changes I made at the same time:
       * Make is_tvs into a *list*, in the right order for the dfun type
         arguments.  This removes the wierd need for the dfun to have the
         same tyvars as the ClsInst template, an invariant I have always
         hated. The cost is that we need to make it a VarSet when matching.
         We could cache an is_tv_set instead.
       * Add a cached is_cls field to the ClsInst, to save fishing
         the Class out of the DFun.  (Renamed is_cls to is_cls_nm.)
       * Make tcSplitDFunTy return the dfun args, not just the *number*
         of dfun args
       * Make InstEnv.instanceHead return just the *head* of the
         instance declaration.  Add instanceSig to return the whole
  19. 22 Dec, 2012 1 commit
    • eir@cis.upenn.edu's avatar
      Implement overlapping type family instances. · 8366792e
      eir@cis.upenn.edu authored
      An ordered, overlapping type family instance is introduced by 'type
      where', followed by equations. See the new section in the user manual
      ( for details. The canonical example is Boolean equality at the
      type family Equals (a :: k) (b :: k) :: Bool
      type instance where
        Equals a a = True
        Equals a b = False
      A branched family instance, such as this one, checks its equations in
      and applies only the first the matches. As explained in the note
      checking within groups] in FamInstEnv.lhs, we must be careful not to
      say, (Equals Int b) to False, because b might later unify with Int.
      This commit includes all of the commits on the overlapping-tyfams
      branch. SPJ
      requested that I combine all my commits over the past several months
      into one
      monolithic commit. The following GHC repos are affected: ghc, testsuite,
      utils/haddock, libraries/template-haskell, and libraries/dph.
      Here are some details for the interested:
      - The definition of CoAxiom has been moved from TyCon.lhs to a
        new file CoAxiom.lhs. I made this decision because of the
        number of definitions necessary to support BranchList.
      - BranchList is a GADT whose type tracks whether it is a
        singleton list or not-necessarily-a-singleton-list. The reason
        I introduced this type is to increase static checking of places
        where GHC code assumes that a FamInst or CoAxiom is indeed a
        singleton. This assumption takes place roughly 10 times
        throughout the code. I was worried that a future change to GHC
        would invalidate the assumption, and GHC might subtly fail to
        do the right thing. By explicitly labeling CoAxioms and
        FamInsts as being Unbranched (singleton) or
        Branched (not-necessarily-singleton), we make this assumption
        explicit and checkable. Furthermore, to enforce the accuracy of
        this label, the list of branches of a CoAxiom or FamInst is
        stored using a BranchList, whose constructors constrain its
        type index appropriately.
      I think that the decision to use BranchList is probably the most
      controversial decision I made from a code design point of view.
      Although I provide conversions to/from ordinary lists, it is more
      efficient to use the brList... functions provided in CoAxiom than
      always to convert. The use of these functions does not wander far
      from the core CoAxiom/FamInst logic.
      BranchLists are motivated and explained in the note [Branched axioms] in
      - The CoAxiom type has changed significantly. You can see the new
        type in CoAxiom.lhs. It uses a CoAxBranch type to track
        branches of the CoAxiom. Correspondingly various functions
        producing and consuming CoAxioms had to change, including the
        binary layout of interface files.
      - To get branched axioms to work correctly, it is important to have a
        of type "apartness": two types are apart if they cannot unify, and no
        substitution of variables can ever get them to unify, even after type
        simplification. (This is different than the normal failure to unify
        of the type family bit.) This notion in encoded in tcApartTys, in
        Because apartness is finer-grained than unification, the tcUnifyTys
        calls tcApartTys.
      - CoreLinting axioms has been updated, both to reflect the new
        form of CoAxiom and to enforce the apartness rules of branch
        application. The formalization of the new rules is in
      - The FamInst type (in types/FamInstEnv.lhs) has changed
        significantly, paralleling the changes to CoAxiom. Of course,
        this forced minor changes in many files.
      - There are several new Notes in FamInstEnv.lhs, including one
        discussing confluent overlap and why we're not doing it.
      - lookupFamInstEnv, lookupFamInstEnvConflicts, and
        lookup_fam_inst_env' (the function that actually does the work)
        have all been more-or-less completely rewritten. There is a
        Note [lookup_fam_inst_env' implementation] describing the
        implementation. One of the changes that affects other files is
        to change the type of matches from a pair of (FamInst, [Type])
        to a new datatype (which now includes the index of the matching
        branch). This seemed a better design.
      - The TySynInstD constructor in Template Haskell was updated to
        use the new datatype TySynEqn. I also bumped the TH version
        number, requiring changes to DPH cabal files. (That's why the
        DPH repo has an overlapping-tyfams branch.)
      - As SPJ requested, I refactored some of the code in HsDecls:
       * splitting up TyDecl into SynDecl and DataDecl, correspondingly
         changing HsTyDefn to HsDataDefn (with only one constructor)
       * splitting FamInstD into TyFamInstD and DataFamInstD and
         splitting FamInstDecl into DataFamInstDecl and TyFamInstDecl
       * making the ClsInstD take a ClsInstDecl, for parallelism with
         InstDecl's other constructors
       * changing constructor TyFamily into FamDecl
       * creating a FamilyDecl type that stores the details for a family
         declaration; this is useful because FamilyDecls can appear in classes
         other decls cannot
       * restricting the associated types and associated type defaults for a
       * class
         to be the new, more restrictive types
       * splitting cid_fam_insts into cid_tyfam_insts and cid_datafam_insts,
         according to the new types
       * perhaps one or two more that I'm overlooking
      None of these changes has far-reaching implications.
      - The user manual, section, is updated to describe the new type
  20. 06 Dec, 2012 1 commit
    • Simon Peyton Jones's avatar
      Stop attempting to "trim" data types in interface files · 9a20e540
      Simon Peyton Jones authored
      Without -O, we previously tried to make interface files smaller
      by not including the data constructors of data types.  But
      there are a lot of exceptions, notably when Template Haskell is
      involved or, more recently, DataKinds.
      However Trac #7445 shows that even without TemplateHaskell, using
      the Data class and invoking Language.Haskell.TH.Quote.dataToExpQ
      is enough to require us to expose the data constructors.
      So I've given up on this "optimisation" -- it's probably not
      important anyway.  Now I'm simply not attempting to trim off
      the data constructors.  The gain in simplicity is worth the
      modest cost in interface file growth, which is limited to the
      bits reqd to describe those data constructors.
  21. 05 Dec, 2012 1 commit
  22. 18 Oct, 2012 1 commit
    • ian@well-typed.com's avatar
      Refactor the way dump flags are handled · d4a19643
      ian@well-typed.com authored
      We were being inconsistent about how we tested whether dump flags
      were enabled; in particular, sometimes we also checked the verbosity,
      and sometimes we didn't.
      This lead to oddities such as "ghc -v4" printing an "Asm code" section
      which didn't contain any code, and "-v4" enabled some parts of
      "-ddump-deriv" but not others.
      Now all the tests use dopt, which also takes the verbosity into account
      as appropriate.
  23. 16 Oct, 2012 1 commit
    • ian@well-typed.com's avatar
      Some alpha renaming · cd33eefd
      ian@well-typed.com authored
      Mostly d -> g (matching DynFlag -> GeneralFlag).
      Also renamed if* to when*, matching the Haskell if/when names
  24. 09 Oct, 2012 1 commit
    • ian@well-typed.com's avatar
      Make the opt_UF_* static flags dynamic · 0a768bcb
      ian@well-typed.com authored
      I also removed the default values from the "Discounts and thresholds"
      note: most of them were no longer up-to-date.
      Along the way I added FloatSuffix to the argument parser, analogous to
  25. 17 Sep, 2012 1 commit
  26. 03 Sep, 2012 1 commit
  27. 28 Aug, 2012 1 commit
  28. 13 Jul, 2012 1 commit
  29. 27 Jun, 2012 1 commit
    • Simon Peyton Jones's avatar
      Add silent superclass parameters (again) · aa1e0976
      Simon Peyton Jones authored
      Silent superclass parameters solve the problem that
      the superclasses of a dicionary construction can easily
      turn out to be (wrongly) bottom.  The problem and solution
      are described in
         Note [Silent superclass arguments] in TcInstDcls
      I first implemented this fix (with Dimitrios) in Dec 2010, but removed
      it again in Jun 2011 becuase we thought it wasn't necessary any
      more. (The reason we thought it wasn't necessary is that we'd stopped
      generating derived superclass constraints for *wanteds*.  But we were
      wrong; that didn't solve the superclass-loop problem.)
      So we have to re-implement it.  It's not hard.  Main features:
        * The IdDetails for a DFunId says how many silent arguments it has
        * A DFunUnfolding describes which dictionary args are
          just parameters (DFunLamArg) and which are a function to apply
          to the parameters (DFunPolyArg).  This adds the DFunArg type
          to CoreSyn
        * Consequential changes to IfaceSyn.  (Binary hi file format changes
        * TcInstDcls changes to generate the right dfuns
        * CoreSubst.exprIsConApp_maybe handles the new DFunUnfolding
      The thing taht is *not* done yet is to alter the vectoriser to
      pass the relevant extra argument when building a PA dictionary.
  30. 22 Jun, 2012 1 commit
  31. 11 Jun, 2012 1 commit
    • Ian Lynagh's avatar
      Pass DynFlags to the LogAction · 5716a2f8
      Ian Lynagh authored
      A side-effect is that we can no longer use the LogAction in
      defaultErrorHandler, as we don't have DynFlags at that point.
      But all that defaultErrorHandler did is to print Strings as
      SevFatal, so now it takes a 'FatalMessager' instead.
  32. 06 Jun, 2012 1 commit
  33. 29 May, 2012 2 commits
  34. 22 Apr, 2012 1 commit
  35. 04 Mar, 2012 1 commit
  36. 16 Jan, 2012 1 commit
  37. 15 Jan, 2012 1 commit
    • chak@cse.unsw.edu.au.'s avatar
      Fix vectorisation of classes · b68bbd86
      chak@cse.unsw.edu.au. authored
      - Make sure that we have no implicit names in ifaces
      - Any vectorisation info makes a module an orphan module
      - Allow 'Show' in vectorised code without vectorising it for the moment
  38. 03 Jan, 2012 1 commit
    • Simon Peyton Jones's avatar
      Major refactoring of CoAxioms · 98a642cf
      Simon Peyton Jones authored
      This patch should have no user-visible effect.  It implements a
      significant internal refactoring of the way that FC axioms are
      handled.  The ultimate goal is to put us in a position to implement
      "pattern-matching axioms".  But the changes here are only does
      refactoring; there is no change in functionality.
       * We now treat data/type family instance declarations very,
         very similarly to types class instance declarations:
         - Renamed InstEnv.Instance as InstEnv.ClsInst, for symmetry with
           FamInstEnv.FamInst.  This change does affect the GHC API, but
           for the better I think.
         - Previously, each family type/data instance declaration gave rise
           to a *TyCon*; typechecking a type/data instance decl produced
           that TyCon.  Now, each type/data instance gives rise to
           a *FamInst*, by direct analogy with each class instance
           declaration giving rise to a ClsInst.
         - Just as each ClsInst contains its evidence, a DFunId, so each FamInst
           contains its evidence, a CoAxiom.  See Note [FamInsts and CoAxioms]
           in FamInstEnv.  The CoAxiom is a System-FC thing, and can relate any
           two types, whereas the FamInst relates directly to the Haskell source
           language construct, and always has a function (F tys) on the LHS.
         - Just as a DFunId has its own declaration in an interface file, so now
           do CoAxioms (see IfaceSyn.IfaceAxiom).
         These changes give rise to almost all the refactoring.
       * We used to have a hack whereby a type family instance produced a dummy
         type synonym, thus
            type instance F Int = Bool -> Bool
         translated to
            axiom FInt :: F Int ~ R:FInt
            type R:FInt = Bool -> Bool
         This was always a hack, and now it's gone.  Instead the type instance
         declaration produces a FamInst, whose axiom has kind
            axiom FInt :: F Int ~ Bool -> Bool
         just as you'd expect.
       * Newtypes are done just as before; they generate a CoAxiom. These
         CoAxioms are "implicit" (do not generate an IfaceAxiom declaration),
         unlike the ones coming from family instance declarations.  See
         Note [Implicit axioms] in TyCon
      On the whole the code gets significantly nicer.  There were consequential
      tidy-ups in the vectoriser, but I think I got them right.
  39. 13 Dec, 2011 1 commit