1. 24 Aug, 2011 1 commit
  2. 16 Aug, 2011 1 commit
  3. 02 Aug, 2011 1 commit
    • Simon Peyton Jones's avatar
      Change the representation of export lists in .hi files · fe44af73
      Simon Peyton Jones authored
      Currently export list in .hi files are partitioned by module
        export M T(C1,C2)
               N f,g
      In each list we only have OccNames, all assumed to come from
      the parent module M or N resp.
      
      This patch changes the representatation so that export lists
      have full Names:
        export M.T(M.C1,M.C2), N.f, N.g
      
      Numerous advatages
        * AvailInfo no longer needs to be parameterised; it always
          contains Names
      
        * Fixes Trac #5306.  This was the main provocation
      
        * Less to-and-fro conversion when reading interface files
      
      It's all generally simpler.  Interface files should not get bigger,
      becuase they have a nice compact representation for Names.
      fe44af73
  4. 16 Jun, 2011 1 commit
  5. 09 Jun, 2011 1 commit
    • Ian Lynagh's avatar
      Refactor SrcLoc and SrcSpan · b2bd63f9
      Ian Lynagh authored
      The "Unhelpful" cases are now in a separate type. This allows us to
      improve various things, e.g.:
      * Most of the panic's in SrcLoc are now gone
      * The Lexer now works with RealSrcSpans rather than SrcSpans, i.e. it
        knows that it has real locations and thus can assume that the line
        number etc really exists
      * Some of the more suspicious cases are no longer necessary, e.g.
        we no longer need this case in advanceSrcLoc:
            advanceSrcLoc loc _ = loc -- Better than nothing
      
      More improvements can probably be made, e.g. tick locations can
      probably use RealSrcSpans too.
      b2bd63f9
  6. 24 Apr, 2011 1 commit
  7. 12 Jan, 2011 1 commit
    • simonpj@microsoft.com's avatar
      Major refactoring of the type inference engine · 27310213
      simonpj@microsoft.com authored
      This patch embodies many, many changes to the contraint solver, which
      make it simpler, more robust, and more beautiful.  But it has taken
      me ages to get right. The forcing issue was some obscure programs
      involving recursive dictionaries, but these eventually led to a
      massive refactoring sweep.
      
      Main changes are:
       * No more "frozen errors" in the monad.  Instead "insoluble
         constraints" are now part of the WantedConstraints type.
      
       * The WantedConstraint type is a product of bags, instead of (as
         before) a bag of sums.  This eliminates a good deal of tagging and
         untagging.
      
       * This same WantedConstraints data type is used
           - As the way that constraints are gathered
           - As a field of an implication constraint
           - As both argument and result of solveWanted
           - As the argument to reportUnsolved
      
       * We do not generate any evidence for Derived constraints. They are
         purely there to allow "impovement" by unifying unification
         variables.
      
       * In consequence, nothing is ever *rewritten* by a Derived
         constraint.  This removes, by construction, all the horrible
         potential recursive-dictionary loops that were making us tear our
         hair out.  No more isGoodRecEv search either. Hurrah!
      
       * We add the superclass Derived constraints during canonicalisation,
         after checking for duplicates.  So fewer superclass constraints
         are generated than before.
      
       * Skolem tc-tyvars no longer carry SkolemInfo.  Instead, the
         SkolemInfo lives in the GivenLoc of the Implication, where it
         can be tidied, zonked, and substituted nicely.  This alone is
         a major improvement.
      
       * Tidying is improved, so that we tend to get t1, t2, t3, rather
         than t1, t11, t111, etc
      
         Moreover, unification variables are always printed with a digit
         (thus a0, a1, etc), so that plain 'a' is available for a skolem
         arising from a type signature etc. In this way,
           (a) We quietly say which variables are unification variables,
               for those who know and care
           (b) Types tend to get printed as the user expects.  If he writes
                   f :: a -> a
                   f = ...blah...
               then types involving 'a' get printed with 'a', rather than
               some tidied variant.
      
       * There are significant improvements in error messages, notably
         in the "Cannot deduce X from Y" messages.
      27310213
  8. 30 Aug, 2010 1 commit
  9. 30 Mar, 2010 1 commit
  10. 29 Oct, 2009 1 commit
    • simonpj@microsoft.com's avatar
      The Big INLINE Patch: totally reorganise way that INLINE pragmas work · 72462499
      simonpj@microsoft.com authored
      This patch has been a long time in gestation and has, as a
      result, accumulated some extra bits and bobs that are only
      loosely related.  I separated the bits that are easy to split
      off, but the rest comes as one big patch, I'm afraid.
      
      Note that:
       * It comes together with a patch to the 'base' library
       * Interface file formats change slightly, so you need to
         recompile all libraries
      
      The patch is mainly giant tidy-up, driven in part by the
      particular stresses of the Data Parallel Haskell project. I don't
      expect a big performance win for random programs.  Still, here are the
      nofib results, relative to the state of affairs without the patch
      
              Program           Size    Allocs   Runtime   Elapsed
      --------------------------------------------------------------------------------
                  Min         -12.7%    -14.5%    -17.5%    -17.8%
                  Max          +4.7%    +10.9%     +9.1%     +8.4%
       Geometric Mean          +0.9%     -0.1%     -5.6%     -7.3%
      
      The +10.9% allocation outlier is rewrite, which happens to have a
      very delicate optimisation opportunity involving an interaction
      of CSE and inlining (see nofib/Simon-nofib-notes). The fact that
      the 'before' case found the optimisation is somewhat accidental.
      Runtimes seem to go down, but I never kno wwhether to really trust
      this number.  Binary sizes wobble a bit, but nothing drastic.
      
      
      The Main Ideas are as follows.
      
      InlineRules
      ~~~~~~~~~~~
      When you say 
            {-# INLINE f #-}
            f x = <rhs>
      you intend that calls (f e) are replaced by <rhs>[e/x] So we
      should capture (\x.<rhs>) in the Unfolding of 'f', and never meddle
      with it.  Meanwhile, we can optimise <rhs> to our heart's content,
      leaving the original unfolding intact in Unfolding of 'f'.
      
      So the representation of an Unfolding has changed quite a bit
      (see CoreSyn).  An INLINE pragma gives rise to an InlineRule 
      unfolding.  
      
      Moreover, it's only used when 'f' is applied to the
      specified number of arguments; that is, the number of argument on 
      the LHS of the '=' sign in the original source definition. 
      For example, (.) is now defined in the libraries like this
         {-# INLINE (.) #-}
         (.) f g = \x -> f (g x)
      so that it'll inline when applied to two arguments. If 'x' appeared
      on the left, thus
         (.) f g x = f (g x)
      it'd only inline when applied to three arguments.  This slightly-experimental
      change was requested by Roman, but it seems to make sense.
      
      Other associated changes
      
      * Moving the deck chairs in DsBinds, which processes the INLINE pragmas
      
      * In the old system an INLINE pragma made the RHS look like
         (Note InlineMe <rhs>)
        The Note switched off optimisation in <rhs>.  But it was quite
        fragile in corner cases. The new system is more robust, I believe.
        In any case, the InlineMe note has disappeared 
      
      * The workerInfo of an Id has also been combined into its Unfolding,
        so it's no longer a separate field of the IdInfo.
      
      * Many changes in CoreUnfold, esp in callSiteInline, which is the critical
        function that decides which function to inline.  Lots of comments added!
      
      * exprIsConApp_maybe has moved to CoreUnfold, since it's so strongly
        associated with "does this expression unfold to a constructor application".
        It can now do some limited beta reduction too, which Roman found 
        was an important.
      
      Instance declarations
      ~~~~~~~~~~~~~~~~~~~~~
      It's always been tricky to get the dfuns generated from instance
      declarations to work out well.  This is particularly important in 
      the Data Parallel Haskell project, and I'm now on my fourth attempt,
      more or less.
      
      There is a detailed description in TcInstDcls, particularly in
      Note [How instance declarations are translated].   Roughly speaking
      we now generate a top-level helper function for every method definition
      in an instance declaration, so that the dfun takes a particularly
      stylised form:
        dfun a d1 d2 = MkD (op1 a d1 d2) (op2 a d1 d2) ...etc...
      
      In fact, it's *so* stylised that we never need to unfold a dfun.
      Instead ClassOps have a special rewrite rule that allows us to
      short-cut dictionary selection.  Suppose dfun :: Ord a -> Ord [a]
                                                  d :: Ord a
      Then   
          compare (dfun a d)  -->   compare_list a d 
      in one rewrite, without first inlining the 'compare' selector
      and the body of the dfun.
      
      To support this
      a) ClassOps have a BuiltInRule (see MkId.dictSelRule)
      b) DFuns have a special form of unfolding (CoreSyn.DFunUnfolding)
         which is exploited in CoreUnfold.exprIsConApp_maybe
      
      Implmenting all this required a root-and-branch rework of TcInstDcls
      and bits of TcClassDcl.
      
      
      Default methods
      ~~~~~~~~~~~~~~~
      If you give an INLINE pragma to a default method, it should be just
      as if you'd written out that code in each instance declaration, including
      the INLINE pragma.  I think that it now *is* so.  As a result, library
      code can be simpler; less duplication.
      
      
      The CONLIKE pragma
      ~~~~~~~~~~~~~~~~~~
      In the DPH project, Roman found cases where he had
      
         p n k = let x = replicate n k
                 in ...(f x)...(g x)....
      
         {-# RULE f (replicate x) = f_rep x #-}
      
      Normally the RULE would not fire, because doing so involves 
      (in effect) duplicating the redex (replicate n k).  A new
      experimental modifier to the INLINE pragma, {-# INLINE CONLIKE
      replicate #-}, allows you to tell GHC to be prepared to duplicate
      a call of this function if it allows a RULE to fire.
      
      See Note [CONLIKE pragma] in BasicTypes
      
      
      Join points
      ~~~~~~~~~~~
      See Note [Case binders and join points] in Simplify
      
      
      Other refactoring
      ~~~~~~~~~~~~~~~~~
      * I moved endPass from CoreLint to CoreMonad, with associated jigglings
      
      * Better pretty-printing of Core
      
      * The top-level RULES (ones that are not rules for locally-defined things)
        are now substituted on every simplifier iteration.  I'm not sure how
        we got away without doing this before.  This entails a bit more plumbing
        in SimplCore.
      
      * The necessary stuff to serialise and deserialise the new
        info across interface files.
      
      * Something about bottoming floats in SetLevels
            Note [Bottoming floats]
      
      * substUnfolding has moved from SimplEnv to CoreSubs, where it belongs
      
      
      --------------------------------------------------------------------------------
              Program           Size    Allocs   Runtime   Elapsed
      --------------------------------------------------------------------------------
                 anna          +2.4%     -0.5%      0.16      0.17
                 ansi          +2.6%     -0.1%      0.00      0.00
                 atom          -3.8%     -0.0%     -1.0%     -2.5%
               awards          +3.0%     +0.7%      0.00      0.00
               banner          +3.3%     -0.0%      0.00      0.00
           bernouilli          +2.7%     +0.0%     -4.6%     -6.9%
                boyer          +2.6%     +0.0%      0.06      0.07
               boyer2          +4.4%     +0.2%      0.01      0.01
                 bspt          +3.2%     +9.6%      0.02      0.02
            cacheprof          +1.4%     -1.0%    -12.2%    -13.6%
             calendar          +2.7%     -1.7%      0.00      0.00
             cichelli          +3.7%     -0.0%      0.13      0.14
              circsim          +3.3%     +0.0%     -2.3%     -9.9%
             clausify          +2.7%     +0.0%      0.05      0.06
        comp_lab_zift          +2.6%     -0.3%     -7.2%     -7.9%
             compress          +3.3%     +0.0%     -8.5%     -9.6%
            compress2          +3.6%     +0.0%    -15.1%    -17.8%
          constraints          +2.7%     -0.6%    -10.0%    -10.7%
         cryptarithm1          +4.5%     +0.0%     -4.7%     -5.7%
         cryptarithm2          +4.3%    -14.5%      0.02      0.02
                  cse          +4.4%     -0.0%      0.00      0.00
                eliza          +2.8%     -0.1%      0.00      0.00
                event          +2.6%     -0.0%     -4.9%     -4.4%
               exp3_8          +2.8%     +0.0%     -4.5%     -9.5%
               expert          +2.7%     +0.3%      0.00      0.00
                  fem          -2.0%     +0.6%      0.04      0.04
                  fft          -6.0%     +1.8%      0.05      0.06
                 fft2          -4.8%     +2.7%      0.13      0.14
             fibheaps          +2.6%     -0.6%      0.05      0.05
                 fish          +4.1%     +0.0%      0.03      0.04
                fluid          -2.1%     -0.2%      0.01      0.01
               fulsom          -4.8%     +9.2%     +9.1%     +8.4%
               gamteb          -7.1%     -1.3%      0.10      0.11
                  gcd          +2.7%     +0.0%      0.05      0.05
          gen_regexps          +3.9%     -0.0%      0.00      0.00
               genfft          +2.7%     -0.1%      0.05      0.06
                   gg          -2.7%     -0.1%      0.02      0.02
                 grep          +3.2%     -0.0%      0.00      0.00
               hidden          -0.5%     +0.0%    -11.9%    -13.3%
                  hpg          -3.0%     -1.8%     +0.0%     -2.4%
                  ida          +2.6%     -1.2%      0.17     -9.0%
                infer          +1.7%     -0.8%      0.08      0.09
              integer          +2.5%     -0.0%     -2.6%     -2.2%
            integrate          -5.0%     +0.0%     -1.3%     -2.9%
              knights          +4.3%     -1.5%      0.01      0.01
                 lcss          +2.5%     -0.1%     -7.5%     -9.4%
                 life          +4.2%     +0.0%     -3.1%     -3.3%
                 lift          +2.4%     -3.2%      0.00      0.00
            listcompr          +4.0%     -1.6%      0.16      0.17
             listcopy          +4.0%     -1.4%      0.17      0.18
             maillist          +4.1%     +0.1%      0.09      0.14
               mandel          +2.9%     +0.0%      0.11      0.12
              mandel2          +4.7%     +0.0%      0.01      0.01
              minimax          +3.8%     -0.0%      0.00      0.00
              mkhprog          +3.2%     -4.2%      0.00      0.00
           multiplier          +2.5%     -0.4%     +0.7%     -1.3%
             nucleic2          -9.3%     +0.0%      0.10      0.10
                 para          +2.9%     +0.1%     -0.7%     -1.2%
            paraffins         -10.4%     +0.0%      0.20     -1.9%
               parser          +3.1%     -0.0%      0.05      0.05
              parstof          +1.9%     -0.0%      0.00      0.01
                  pic          -2.8%     -0.8%      0.01      0.02
                power          +2.1%     +0.1%     -8.5%     -9.0%
               pretty         -12.7%     +0.1%      0.00      0.00
               primes          +2.8%     +0.0%      0.11      0.11
            primetest          +2.5%     -0.0%     -2.1%     -3.1%
               prolog          +3.2%     -7.2%      0.00      0.00
               puzzle          +4.1%     +0.0%     -3.5%     -8.0%
               queens          +2.8%     +0.0%      0.03      0.03
              reptile          +2.2%     -2.2%      0.02      0.02
              rewrite          +3.1%    +10.9%      0.03      0.03
                 rfib          -5.2%     +0.2%      0.03      0.03
                  rsa          +2.6%     +0.0%      0.05      0.06
                  scc          +4.6%     +0.4%      0.00      0.00
                sched          +2.7%     +0.1%      0.03      0.03
                  scs          -2.6%     -0.9%     -9.6%    -11.6%
               simple          -4.0%     +0.4%    -14.6%    -14.9%
                solid          -5.6%     -0.6%     -9.3%    -14.3%
              sorting          +3.8%     +0.0%      0.00      0.00
               sphere          -3.6%     +8.5%      0.15      0.16
               symalg          -1.3%     +0.2%      0.03      0.03
                  tak          +2.7%     +0.0%      0.02      0.02
            transform          +2.0%     -2.9%     -8.0%     -8.8%
             treejoin          +3.1%     +0.0%    -17.5%    -17.8%
            typecheck          +2.9%     -0.3%     -4.6%     -6.6%
              veritas          +3.9%     -0.3%      0.00      0.00
                 wang          -6.2%     +0.0%      0.18     -9.8%
            wave4main         -10.3%     +2.6%     -2.1%     -2.3%
         wheel-sieve1          +2.7%     -0.0%     +0.3%     -0.6%
         wheel-sieve2          +2.7%     +0.0%     -3.7%     -7.5%
                 x2n1          -4.1%     +0.1%      0.03      0.04
      --------------------------------------------------------------------------------
                  Min         -12.7%    -14.5%    -17.5%    -17.8%
                  Max          +4.7%    +10.9%     +9.1%     +8.4%
       Geometric Mean          +0.9%     -0.1%     -5.6%     -7.3%
      72462499
  11. 21 Aug, 2009 1 commit
  12. 28 May, 2009 1 commit
    • simonpj@microsoft.com's avatar
      Improve printing of Orig RdrNames · 30ced404
      simonpj@microsoft.com authored
      In Tempate Haskell -ddump-splices, the "after" expression is populated 
      with RdrNames, many of which are Orig things.  We used to print these
      fully-qualified, but that's a bit heavy.
      
      This patch refactors the code a bit so that the same print-unqualified
      mechanism we use for Names also works for RdrNames.  Lots of comments
      too, because it took me a while to figure out how it all worked again.
      30ced404
  13. 11 Aug, 2008 1 commit
  14. 07 Aug, 2008 1 commit
  15. 04 Aug, 2008 1 commit
  16. 28 May, 2008 1 commit
    • Simon Marlow's avatar
      Use MD5 checksums for recompilation checking (fixes #1372, #1959) · 526c3af1
      Simon Marlow authored
      This is a much more robust way to do recompilation checking.  The idea
      is to create a fingerprint of the ABI of an interface, and track
      dependencies by recording the fingerprints of ABIs that a module
      depends on.  If any of those ABIs have changed, then we need to
      recompile.
      
      In bug #1372 we weren't recording dependencies on package modules,
      this patch fixes that by recording fingerprints of package modules
      that we depend on.  Within a package there is still fine-grained
      recompilation avoidance as before.
      
      We currently use MD5 for fingerprints, being a good compromise between
      efficiency and security.  We're not worried about attackers, but we
      are worried about accidental collisions.
      
      All the MD5 sums do make interface files a bit bigger, but compile
      times on the whole are about the same as before.  Recompilation
      avoidance should be a bit more accurate than in 6.8.2 due to fixing
      #1959, especially when using -O.
      526c3af1
  17. 12 Apr, 2008 1 commit
  18. 26 Jan, 2008 1 commit
  19. 17 Jan, 2008 1 commit
    • Isaac Dupree's avatar
      lots of portability changes (#1405) · 206b4dec
      Isaac Dupree authored
      re-recording to avoid new conflicts was too hard, so I just put it
      all in one big patch :-(  (besides, some of the changes depended on
      each other.)  Here are what the component patches were:
      
      Fri Dec 28 11:02:55 EST 2007  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * document BreakArray better
      
      Fri Dec 28 11:39:22 EST 2007  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * properly ifdef BreakArray for GHCI
      
      Fri Jan  4 13:50:41 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * change ifs on __GLASGOW_HASKELL__ to account for... (#1405)
        for it not being defined. I assume it being undefined implies
        a compiler with relatively modern libraries but without most
        unportable glasgow extensions.
      
      Fri Jan  4 14:21:21 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * MyEither-->EitherString to allow Haskell98 instance
      
      Fri Jan  4 16:13:29 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * re-portabilize Pretty, and corresponding changes
      
      Fri Jan  4 17:19:55 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * Augment FastTypes to be much more complete
      
      Fri Jan  4 20:14:19 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * use FastFunctions, cleanup FastString slightly
      
      Fri Jan  4 21:00:22 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * Massive de-"#", mostly Int# --> FastInt (#1405)
      
      Fri Jan  4 21:02:49 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * miscellaneous unnecessary-extension-removal
      
      Sat Jan  5 19:30:13 EST 2008  Isaac Dupree <id@isaac.cedarswampstudios.org>
        * add FastFunctions
      206b4dec
  20. 14 Nov, 2007 1 commit
  21. 10 Sep, 2007 1 commit
    • Simon Marlow's avatar
      FIX #903: mkWWcpr: not a product · 3b1438a9
      Simon Marlow authored
      This fixes the long-standing bug that prevents some code with
      mutally-recursive modules from being compiled with --make and -O,
      including GHC itself.  See the comments for details.
      
      There are some additional cleanups that were forced/enabled by this
      patch: I removed importedSrcLoc/importedSrcSpan: it wasn't adding any
      useful information, since a Name already contains its defining Module.
      In fact when re-typechecking an interface file we were wrongly
      replacing the interesting SrcSpans in the Names with boring
      importedSrcSpans, which meant that location information could degrade
      after reloading modules.  Also, recreating all these Names was a waste
      of space/time.
      3b1438a9
  22. 06 Sep, 2007 1 commit
    • Simon Marlow's avatar
      FIX #1465, error messages could sometimes say things like "A.T doesn't match A.T" · 42181975
      Simon Marlow authored
      This turned out to be a black hole, however we believe we now have a
      plan that does the right thing and shouldn't need to change again.
      Error messages will only ever refer to a name in an unambiguous way,
      falling back to <package>:<module>.<name> if no unambiguous shorter
      variant can be found.  See HscTypes.mkPrintUnqualified for the
      details.
      
      Earlier hacks to work around this problem have been removed (TcSimplify).
      42181975
  23. 04 Sep, 2007 1 commit
  24. 03 Sep, 2007 1 commit
  25. 01 Sep, 2007 1 commit
  26. 11 May, 2007 1 commit
  27. 25 Apr, 2007 1 commit
  28. 29 Nov, 2006 1 commit
    • andy@galois.com's avatar
      TickBox representation change · 8100cd43
      andy@galois.com authored
      This changes the internal representation of TickBoxes,
      from
              Note (TickBox "module" n)  <expr>
      into
      
              case tick<module,n> of
                _ -> <expr>
      
      tick has type :: #State #World, when the module and tick numbe
      are stored inside IdInfo.
      
      Binary tick boxes change from
      
               Note (BinaryTickBox "module" t f) <expr>
      
      into
      
                btick<module,t,f> <expr>
      
      btick has type :: Bool -> Bool, with the module and tick number
      stored inside IdInfo.
      8100cd43
  29. 11 Oct, 2006 2 commits
    • Simon Marlow's avatar
      Module header tidyup, phase 1 · 49c98d14
      Simon Marlow authored
      This patch is a start on removing import lists and generally tidying
      up the top of each module.  In addition to removing import lists:
      
         - Change DATA.IOREF -> Data.IORef etc.
         - Change List -> Data.List etc.
         - Remove $Id$
         - Update copyrights
         - Re-order imports to put non-GHC imports last
         - Remove some unused and duplicate imports
      49c98d14
    • Simon Marlow's avatar
      Interface file optimisation and removal of nameParent · b00b5bc0
      Simon Marlow authored
      This large commit combines several interrelated changes:
      
        - IfaceSyn now contains actual Names rather than the special
          IfaceExtName type.  The binary interface file contains
          a symbol table of Names, where each entry is a (package,
          ModuleName, OccName) triple.  Names in the IfaceSyn point
          to entries in the symbol table.
      
          This reduces the size of interface files, which should
          hopefully improve performance (not measured yet).
      
          The toIfaceXXX functions now do not need to pass around
          a function from Name -> IfaceExtName, which makes that
          code simpler.
      
        - Names now do not point directly to their parents, and the
          nameParent operation has gone away.  It turned out to be hard to
          keep this information consistent in practice, and the parent info
          was only valid in some Names.  Instead we made the following
          changes:
      
          * ImportAvails contains a new field 
                imp_parent :: NameEnv AvailInfo
            which gives the family info for any Name in scope, and
            is used by the renamer when renaming export lists, amongst
            other things.  This info is thrown away after renaming.
      
          * The mi_ver_fn field of ModIface now maps to
            (OccName,Version) instead of just Version, where the
            OccName is the parent name.  This mapping is used when
            constructing the usage info for dependent modules.
            There may be entries in mi_ver_fn for things that are not in
            scope, whereas imp_parent only deals with in-scope things.
      
          * The md_exports field of ModDetails now contains
            [AvailInfo] rather than NameSet.  This gives us
            family info for the exported names of a module.
      
      Also:
      
         - ifaceDeclSubBinders moved to IfaceSyn (seems like the
           right place for it).
      
         - heavily refactored renaming of import/export lists.
      
         - Unfortunately external core is now broken, as it relied on
           IfaceSyn.  It requires some attention.
      b00b5bc0
  30. 18 Sep, 2006 1 commit
    • chak@cse.unsw.edu.au.'s avatar
      Type tags in import/export lists · 0cfba505
      chak@cse.unsw.edu.au. authored
      Tue Sep 12 16:57:32 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
        * Type tags in import/export lists
        - To write something like GMapKey(type GMap, empty, lookup, insert)
        - Requires -findexed-types
      0cfba505
  31. 25 Jul, 2006 2 commits
    • Simon Marlow's avatar
      Unbox the Unique stored in a Name · ddb04482
      Simon Marlow authored
      I measured that this makes the comiler allocate a bit more, but it
      might also make it faster and reduce residency.  The extra allocation
      is probably just because we're not inlining enough somewhere, so I
      think this change is a step in the right direction.
      ddb04482
    • Simon Marlow's avatar
      Generalise Package Support · 61d2625a
      Simon Marlow authored
      This patch pushes through one fundamental change: a module is now
      identified by the pair of its package and module name, whereas
      previously it was identified by its module name alone.  This means
      that now a program can contain multiple modules with the same name, as
      long as they belong to different packages.
      
      This is a language change - the Haskell report says nothing about
      packages, but it is now necessary to understand packages in order to
      understand GHC's module system.  For example, a type T from module M
      in package P is different from a type T from module M in package Q.
      Previously this wasn't an issue because there could only be a single
      module M in the program.
      
      The "module restriction" on combining packages has therefore been
      lifted, and a program can contain multiple versions of the same
      package.
      
      Note that none of the proposed syntax changes have yet been
      implemented, but the architecture is geared towards supporting import
      declarations qualified by package name, and that is probably the next
      step.
      
      It is now necessary to specify the package name when compiling a
      package, using the -package-name flag (which has been un-deprecated).
      Fortunately Cabal still uses -package-name.
      
      Certain packages are "wired in".  Currently the wired-in packages are:
      base, haskell98, template-haskell and rts, and are always referred to
      by these versionless names.  Other packages are referred to with full
      package IDs (eg. "network-1.0").  This is because the compiler needs
      to refer to entities in the wired-in packages, and we didn't want to
      bake the version of these packages into the comiler.  It's conceivable
      that someone might want to upgrade the base package independently of
      GHC.
      
      Internal changes:
      
        - There are two module-related types:
      
              ModuleName      just a FastString, the name of a module
              Module          a pair of a PackageId and ModuleName
      
          A mapping from ModuleName can be a UniqFM, but a mapping from Module
          must be a FiniteMap (we provide it as ModuleEnv).
      
        - The "HomeModules" type that was passed around the compiler is now
          gone, replaced in most cases by the current package name which is
          contained in DynFlags.  We can tell whether a Module comes from the
          current package by comparing its package name against the current
          package.
      
        - While I was here, I changed PrintUnqual to be a little more useful:
          it now returns the ModuleName that the identifier should be qualified
          with according to the current scope, rather than its original
          module.  Also, PrintUnqual tells whether to qualify module names with
          package names (currently unused).
      
      Docs to follow.
      61d2625a
  32. 07 Apr, 2006 1 commit
    • Simon Marlow's avatar
      Reorganisation of the source tree · 0065d5ab
      Simon Marlow authored
      Most of the other users of the fptools build system have migrated to
      Cabal, and with the move to darcs we can now flatten the source tree
      without losing history, so here goes.
      
      The main change is that the ghc/ subdir is gone, and most of what it
      contained is now at the top level.  The build system now makes no
      pretense at being multi-project, it is just the GHC build system.
      
      No doubt this will break many things, and there will be a period of
      instability while we fix the dependencies.  A straightforward build
      should work, but I haven't yet fixed binary/source distributions.
      Changes to the Building Guide will follow, too.
      0065d5ab
  33. 25 Jan, 2006 1 commit
    • simonpj@microsoft.com's avatar
      Simon's big boxy-type commit · ac10f840
      simonpj@microsoft.com authored
      This very large commit adds impredicativity to GHC, plus
      numerous other small things.
        
      *** WARNING: I have compiled all the libraries, and
      ***	     a stage-2 compiler, and everything seems
      ***	     fine.  But don't grab this patch if you 
      ***	     can't tolerate a hiccup if something is
      ***	     broken.
        
      The big picture is this:
      
      a) GHC handles impredicative polymorphism, as described in the
         "Boxy types: type inference for higher-rank types and
         impredicativity" paper
      
      b) GHC handles GADTs in the new simplified (and very sligtly less
         epxrssive) way described in the
         "Simple unification-based type inference for GADTs" paper
      
        
      But there are lots of smaller changes, and since it was pre-Darcs
      they are not individually recorded.
        
      Some things to watch out for:
        
      c)   The story on lexically-scoped type variables has changed, as per
           my email.  I append the story below for completeness, but I 
           am still not happy with it, and it may change again.  In particular,
           the new story does not allow a pattern-bound scoped type variable
           to be wobbly, so (\(x::[a]) -> ...) is usually rejected.  This is
           more restrictive than before, and we might loosen up again.
        
      d)   A consequence of adding impredicativity is that GHC is a bit less
           gung ho about converting automatically between
        	(ty1 -> forall a. ty2)    and    (forall a. ty1 -> ty2)
           In particular, you may need to eta-expand some functions to make
           typechecking work again.
         
           Furthermore, functions are now invariant in their argument types,
           rather than being contravariant.  Again, the main consequence is
           that you may occasionally need to eta-expand function arguments when
           using higher-rank polymorphism.
        
      
      Please test, and let me know of any hiccups
      
      
      Scoped type variables in GHC
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      	January 2006
      
      0) Terminology.
         
         A *pattern binding* is of the form
      	pat = rhs
      
         A *function binding* is of the form
      	f pat1 .. patn = rhs
      
         A binding of the formm
      	var = rhs
         is treated as a (degenerate) *function binding*.
      
      
         A *declaration type signature* is a separate type signature for a
         let-bound or where-bound variable:
      	f :: Int -> Int
      
         A *pattern type signature* is a signature in a pattern: 
      	\(x::a) -> x
      	f (x::a) = x
      
         A *result type signature* is a signature on the result of a
         function definition:
      	f :: forall a. [a] -> a
      	head (x:xs) :: a = x
      
         The form
      	x :: a = rhs
         is treated as a (degnerate) function binding with a result
         type signature, not as a pattern binding.
      
      1) The main invariants:
      
           A) A lexically-scoped type variable always names a (rigid)
       	type variable (not an arbitrary type).  THIS IS A CHANGE.
              Previously, a scoped type variable named an arbitrary *type*.
      
           B) A type signature always describes a rigid type (since
      	its free (scoped) type variables name rigid type variables).
      	This is also a change, a consequence of (A).
      
           C) Distinct lexically-scoped type variables name distinct
      	rigid type variables.  This choice is open; 
      
      2) Scoping
      
      2(a) If a declaration type signature has an explicit forall, those type
         variables are brought into scope in the right hand side of the 
         corresponding binding (plus, for function bindings, the patterns on
         the LHS).  
      	f :: forall a. a -> [a]
      	f (x::a) = [x :: a, x]
         Both occurences of 'a' in the second line are bound by 
         the 'forall a' in the first line
      
         A declaration type signature *without* an explicit top-level forall
         is implicitly quantified over all the type variables that are
         mentioned in the type but not already in scope.  GHC's current
         rule is that this implicit quantification does *not* bring into scope
         any new scoped type variables.
      	f :: a -> a
      	f x = ...('a' is not in scope here)...
         This gives compatibility with Haskell 98
      
      2(b) A pattern type signature implicitly brings into scope any type
         variables mentioned in the type that are not already into scope.
         These are called *pattern-bound type variables*.
      	g :: a -> a -> [a]
      	g (x::a) (y::a) = [y :: a, x]
         The pattern type signature (x::a) brings 'a' into scope.
         The 'a' in the pattern (y::a) is bound, as is the occurrence on 
         the RHS.  
      
         A pattern type siganture is the only way you can bring existentials 
         into scope.
      	data T where
      	  MkT :: forall a. a -> (a->Int) -> T
      
      	f x = case x of
      		MkT (x::a) f -> f (x::a)
      
      2a) QUESTION
      	class C a where
      	  op :: forall b. b->a->a
      
      	instance C (T p q) where
      	  op = <rhs>
          Clearly p,q are in scope in <rhs>, but is 'b'?  Not at the moment.
          Nor can you add a type signature for op in the instance decl.
          You'd have to say this:
      	instance C (T p q) where
      	  op = let op' :: forall b. ...
      	           op' = <rhs>
      	       in op'
      
      3) A pattern-bound type variable is allowed only if the pattern's
         expected type is rigid.  Otherwise we don't know exactly *which*
         skolem the scoped type variable should be bound to, and that means
         we can't do GADT refinement.  This is invariant (A), and it is a 
         big change from the current situation.
      
      	f (x::a) = x	-- NO; pattern type is wobbly
      	
      	g1 :: b -> b
      	g1 (x::b) = x	-- YES, because the pattern type is rigid
      
      	g2 :: b -> b
      	g2 (x::c) = x	-- YES, same reason
      
      	h :: forall b. b -> b
      	h (x::b) = x	-- YES, but the inner b is bound
      
      	k :: forall b. b -> b
      	k (x::c) = x	-- NO, it can't be both b and c
      
      3a) You cannot give different names for the same type variable in the same scope
          (Invariant (C)):
      
      	f1 :: p -> p -> p		-- NO; because 'a' and 'b' would be
      	f1 (x::a) (y::b) = (x::a)	--     bound to the same type variable
      
      	f2 :: p -> p -> p		-- OK; 'a' is bound to the type variable
      	f2 (x::a) (y::a) = (x::a)	--     over which f2 is quantified
      					-- NB: 'p' is not lexically scoped
      
      	f3 :: forall p. p -> p -> p	-- NO: 'p' is now scoped, and is bound to
      	f3 (x::a) (y::a) = (x::a)	--     to the same type varialble as 'a'
      
      	f4 :: forall p. p -> p -> p	-- OK: 'p' is now scoped, and its occurences
      	f4 (x::p) (y::p) = (x::p)	--     in the patterns are bound by the forall
      
      
      3b) You can give a different name to the same type variable in different
          disjoint scopes, just as you can (if you want) give diferent names to 
          the same value parameter
      
      	g :: a -> Bool -> Maybe a
      	g (x::p) True  = Just x  :: Maybe p
      	g (y::q) False = Nothing :: Maybe q
      
      3c) Scoped type variables respect alpha renaming. For example, 
          function f2 from (3a) above could also be written:
      	f2' :: p -> p -> p
      	f2' (x::b) (y::b) = x::b
         where the scoped type variable is called 'b' instead of 'a'.
      
      
      4) Result type signatures obey the same rules as pattern types signatures.
         In particular, they can bind a type variable only if the result type is rigid
      
      	f x :: a = x	-- NO
      
      	g :: b -> b
      	g x :: b = x	-- YES; binds b in rhs
      
      5) A *pattern type signature* in a *pattern binding* cannot bind a 
         scoped type variable
      
      	(x::a, y) = ...		-- Legal only if 'a' is already in scope
      
         Reason: in type checking, the "expected type" of the LHS pattern is
         always wobbly, so we can't bind a rigid type variable.  (The exception
         would be for an existential type variable, but existentials are not
         allowed in pattern bindings either.)
       
         Even this is illegal
      	f :: forall a. a -> a
      	f x = let ((y::b)::a, z) = ... 
      	      in 
         Here it looks as if 'b' might get a rigid binding; but you can't bind
         it to the same skolem as a.
      
      6) Explicitly-forall'd type variables in the *declaration type signature(s)*
         for a *pattern binding* do not scope AT ALL.
      
      	x :: forall a. a->a	  -- NO; the forall a does 
      	Just (x::a->a) = Just id  --     not scope at all
      
      	y :: forall a. a->a
      	Just y = Just (id :: a->a)  -- NO; same reason
      
         THIS IS A CHANGE, but one I bet that very few people will notice.
         Here's why:
      
      	strange :: forall b. (b->b,b->b)
      	strange = (id,id)
      
      	x1 :: forall a. a->a
      	y1 :: forall b. b->b
      	(x1,y1) = strange
      
          This is legal Haskell 98 (modulo the forall). If both 'a' and 'b'
          both scoped over the RHS, they'd get unified and so cannot stand
          for distinct type variables. One could *imagine* allowing this:
         
      	x2 :: forall a. a->a
      	y2 :: forall a. a->a
      	(x2,y2) = strange
      
          using the very same type variable 'a' in both signatures, so that
          a single 'a' scopes over the RHS.  That seems defensible, but odd,
          because though there are two type signatures, they introduce just
          *one* scoped type variable, a.
      
      7) Possible extension.  We might consider allowing
      	\(x :: [ _ ]) -> <expr>
          where "_" is a wild card, to mean "x has type list of something", without
          naming the something.
      ac10f840
  34. 06 Jan, 2006 1 commit
    • simonmar's avatar
      [project @ 2006-01-06 16:30:17 by simonmar] · 9d7da331
      simonmar authored
      Add support for UTF-8 source files
      
      GHC finally has support for full Unicode in source files.  Source
      files are now assumed to be UTF-8 encoded, and the full range of
      Unicode characters can be used, with classifications recognised using
      the implementation from Data.Char.  This incedentally means that only
      the stage2 compiler will recognise Unicode in source files, because I
      was too lazy to port the unicode classifier code into libcompat.
      
      Additionally, the following synonyms for keywords are now recognised:
      
        forall symbol 	(U+2200)	forall
        right arrow   	(U+2192)	->
        left arrow   		(U+2190)	<-
        horizontal ellipsis 	(U+22EF)	..
      
      there are probably more things we could add here.
      
      This will break some source files if Latin-1 characters are being used.
      In most cases this should result in a UTF-8 decoding error.  Later on
      if we want to support more encodings (perhaps with a pragma to specify
      the encoding), I plan to do it by recoding into UTF-8 before parsing.
      
      Internally, there were some pretty big changes:
      
        - FastStrings are now stored in UTF-8
      
        - Z-encoding has been moved right to the back end.  Previously we
          used to Z-encode every identifier on the way in for simplicity,
          and only decode when we needed to show something to the user.
          Instead, we now keep every string in its UTF-8 encoding, and
          Z-encode right before printing it out.  To avoid Z-encoding the
          same string multiple times, the Z-encoding is cached inside the
          FastString the first time it is requested.
      
          This speeds up the compiler - I've measured some definite
          improvement in parsing at least, and I expect compilations overall
          to be faster too.  It also cleans up a lot of cruft from the
          OccName interface.  Z-encoding is nicely hidden inside the
          Outputable instance for Names & OccNames now.
      
        - StringBuffers are UTF-8 too, and are now represented as
          ForeignPtrs.
      
        - I've put together some test cases, not by any means exhaustive,
          but there are some interesting UTF-8 decoding error cases that
          aren't obvious.  Also, take a look at unicode001.hs for a demo.
      9d7da331
  35. 25 Jul, 2005 1 commit
  36. 28 Apr, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-04-28 10:09:41 by simonpj] · dd313897
      simonpj authored
      This big commit does several things at once (aeroplane hacking)
      which change the format of interface files.  
      
      	So you'll need to recompile your libraries!
      
      1. The "stupid theta" of a newtype declaration
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      Retain the "stupid theta" in a newtype declaration.
      For some reason this was being discarded, and putting it
      back in meant changing TyCon and IfaceSyn slightly.
         
      
      2. Overlap flags travel with the instance
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      Arrange that the ability to support overlap and incoherence
      is a property of the *instance declaration* rather than the
      module that imports the instance decl.  This allows a library
      writer to define overlapping instance decls without the
      library client having to know.  
      
      The implementation is that in an Instance we store the
      overlap flag, and preseve that across interface files
      
      
      3. Nuke the "instnce pool" and "rule pool"
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      A major tidy-up and simplification of the way that instances
      and rules are sucked in from interface files.  Up till now
      an instance decl has been held in a "pool" until its "gates" 
      (a set of Names) are in play, when the instance is typechecked
      and added to the InstEnv in the ExternalPackageState.  
      This is complicated and error-prone; it's easy to suck in 
      too few (and miss an instance) or too many (and thereby be
      forced to suck in its type constructors, etc).
      
      Now, as we load an instance from an interface files, we 
      put it straight in the InstEnv... but the Instance we put in
      the InstEnv has some Names (the "rough-match" names) that 
      can be used on lookup to say "this Instance can't match".
      The detailed dfun is only read lazily, and the rough-match
      thing meansn it is'nt poked on until it has a chance of
      being needed.
      
      This simply continues the successful idea for Ids, whereby
      they are loaded straightaway into the TypeEnv, but their
      TyThing is a lazy thunk, not poked on until the thing is looked
      up.
      
      Just the same idea applies to Rules.
      
      On the way, I made CoreRule and Instance into full-blown records
      with lots of info, with the same kind of key status as TyCon or 
      DataCon or Class.  And got rid of IdCoreRule altogether.   
      It's all much more solid and uniform, but it meant touching
      a *lot* of modules.
      
      
      4. Allow instance decls in hs-boot files
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      Allowing instance decls in hs-boot files is jolly useful, becuase
      in a big mutually-recursive bunch of data types, you want to give
      the instances with the data type declarations.  To achieve this
      
      * The hs-boot file makes a provisional name for the dict-fun, something
        like $fx9.
      
      * When checking the "mother module", we check that the instance
        declarations line up (by type) and generate bindings for the 
        boot dfuns, such as
      	$fx9 = $f2
        where $f2 is the dfun generated by the mother module
      
      * In doing this I decided that it's cleaner to have DFunIds get their
        final External Name at birth.  To do that they need a stable OccName,
        so I have an integer-valued dfun-name-supply in the TcM monad.
        That keeps it simple.
      
      This feature is hardly tested yet.
      
      
      5. Tidy up tidying, and Iface file generation
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      main/TidyPgm now has two entry points:
      
        simpleTidyPgm is for hi-boot files, when typechecking only
        (not yet implemented), and potentially when compiling without -O.
        It ignores the bindings, and generates a nice small TypeEnv.
      
        optTidyPgm is the normal case: compiling with -O.  It generates a
        TypeEnv rich in IdInfo
      
      MkIface.mkIface now only generates a ModIface.  A separate
      procedure, MkIface.writeIfaceFile, writes the file out to disk.
      dd313897
  37. 08 Mar, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-03-08 17:12:51 by simonmar] · a8a2fc9c
      simonmar authored
      Fix something that's been bugging me for a while: by default, -ddump-*
      output doesn't include uniques when it outputs internal names, but in
      most cases you need them because the output hasn't been tidied, so you
      end up doing -dppr-debug which is overkill.
      
      Now, -ddump-* prints uniques for internal names by default.  This
      shouldn't affect anything else.
      a8a2fc9c
  38. 25 Feb, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-02-25 13:06:31 by simonpj] · 8e67f550
      simonpj authored
      ---------------------------------------------
      Type signatures are no longer instantiated with skolem constants
      	---------------------------------------------
      
      	Merge to STABLE
      
      Consider
      
        p :: a
        q :: b
        (p,q,r) = (r,r,p)
      
      Here, 'a' and 'b' end up being the same, because they are both bound
      to the type for 'r', which is just a meta type variable.  So 'a' and 'b'
      can't be skolems.
      
      Sigh.  This commit goes back to an earlier way of doing things, by
      arranging that type signatures get instantiated with *meta* type
      variables; then at the end we must check that they have not been
      unified with types, nor with each other.
      
      This is a real bore.  I had to do quite a bit of related fiddling around
      to make error messages come out right.  Improved one or two.
      
      Also a small unrelated fix to make
      	:i (:+)
      print with parens in ghci.  Sorry this got mixed up in the same commit.
      8e67f550