1. 19 Sep, 2010 1 commit
    • Edward Z. Yang's avatar
      Interruptible FFI calls with pthread_kill and CancelSynchronousIO. v4 · 83d563cb
      Edward Z. Yang authored
      This is patch that adds support for interruptible FFI calls in the form
      of a new foreign import keyword 'interruptible', which can be used
      instead of 'safe' or 'unsafe'.  Interruptible FFI calls act like safe
      FFI calls, except that the worker thread they run on may be interrupted.
      
      Internally, it replaces BlockedOnCCall_NoUnblockEx with
      BlockedOnCCall_Interruptible, and changes the behavior of the RTS
      to not modify the TSO_ flags on the event of an FFI call from
      a thread that was interruptible.  It also modifies the bytecode
      format for foreign call, adding an extra Word16 to indicate
      interruptibility.
      
      The semantics of interruption vary from platform to platform, but the
      intent is that any blocking system calls are aborted with an error code.
      This is most useful for making function calls to system library
      functions that support interrupting.  There is no support for pre-Vista
      Windows.
      
      There is a partner testsuite patch which adds several tests for this
      functionality.
      83d563cb
  2. 15 Sep, 2010 1 commit
  3. 06 Sep, 2010 1 commit
  4. 06 May, 2010 1 commit
  5. 17 Mar, 2010 1 commit
  6. 04 Mar, 2010 1 commit
    • simonpj@microsoft.com's avatar
      Refactor part of the renamer to fix Trac #3901 · f1cc3eb9
      simonpj@microsoft.com authored
      This one was bigger than I anticipated!  The problem was that were
      were gathering the binders from a pattern before renaming -- but with
      record wild-cards we don't know what variables are bound by C {..}
      until after the renamer has filled in the "..".
      
      So this patch does the following
      
      * Change all the collect-X-Binders functions in HsUtils so that
        they expect to only be called *after* renaming.  That means they
        don't need to return [Located id] but just [id].  Which turned out
        to be a very worthwhile simplification all by itself.
      
      * Refactor the renamer, and in ptic RnExpr.rnStmt, so that it
        doesn't need to use collectLStmtsBinders on pre-renamed Stmts.
      
      * This in turn required me to understand how GroupStmt and
        TransformStmts were renamed.  Quite fiddly. I rewrote most of it;
        result is much shorter.
      
      * In doing so I flattened HsExpr.GroupByClause into its parent
        GroupStmt, with trivial knock-on effects in other files.
      
      Blargh.
      f1cc3eb9
  7. 10 Feb, 2010 2 commits
    • simonpj@microsoft.com's avatar
      Keep track of explicit kinding in HsTyVarBndr; plus fix Trac #3845 · 836b1e90
      simonpj@microsoft.com authored
      To print HsTypes correctly we should remember whether the Kind on
      a HsTyVarBndr came from type inference, or was put there by the
      user.  See Note [Printing KindedTyVars] in HsTypes.  So instead of
      changing a UserTyVar to a KindedTyVar during kind checking, we
      simply add a PostTcKind to the UserTyVar.
      
      The change was provoked by Trac #3830, although other changes
      mean that #3830 gets a diferent and better error message now.
      So this patch is simply doing the Right Thing for the future.
      
      This patch also fixes Trac #3845, which was caused by a *type splice*
      not remembering the free *term variables* mentioned in it.  Result
      was that we build a 'let' when it should have been 'letrec'.
      Hence a new FreeVars field in HsSpliceTy.
      
      While I was at it, I got rid of HsSpliceTyOut and use a PostTcKind
      on HsSpliceTy instead, just like on the UserTyVar.
      836b1e90
    • simonpj@microsoft.com's avatar
      Several TH/quasiquote changes · 6f8ff0bb
      simonpj@microsoft.com authored
      a) Added quasi-quote forms for
            declarations
            types
         e.g.   f :: [$qq| ... |]
      
      b) Allow Template Haskell pattern quotes (but not splices)
         e.g.  f x = [p| Int -> $x |]
      
      c) Improve pretty-printing for HsPat to remove superfluous
         parens.  (This isn't TH related really, but it affects
         some of the same code.)
      
      
      A consequence of (a) is that when gathering and grouping declarations
      in RnSource.findSplice, we must expand quasiquotes as we do so.
      Otherwise it's all fairly straightforward.  I did a little bit of
      refactoring in TcSplice.
      
      User-manual changes still to come.
      6f8ff0bb
  8. 20 Jan, 2010 1 commit
    • simonpj@microsoft.com's avatar
      Fix Trac #3813: unused variables in GHCi bindings · 85f969a6
      simonpj@microsoft.com authored
      In a GHCi stmt we don't want to report unused variables, 
      because we don't know the scope of the binding, eg
      
      	Prelude> x <- blah
      
      Fixing this needed a little more info about the context of the stmt,
      thus the new constructor GhciStmt in the HsStmtContext type.
      85f969a6
  9. 04 Jan, 2010 1 commit
  10. 30 Oct, 2009 1 commit
  11. 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
  12. 10 Sep, 2009 1 commit
    • simonpj@microsoft.com's avatar
      Three improvements to Template Haskell (fixes #3467) · 1e436f2b
      simonpj@microsoft.com authored
      This patch implements three significant improvements to Template Haskell.
        
      Declaration-level splices with no "$" 
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      This change simply allows you to omit the "$(...)" wrapper for 
      declaration-level TH splices.  An expression all by itself is
      not legal, so we now treat it as a TH splice.  Thus you can now
      say
      	data T = T1 | T2
       	deriveMyStuff ''T
      
      where deriveMyStuff :: Name -> Q [Dec]
      This makes a much nicer interface for clients of libraries that use
      TH: no scary $(deriveMyStuff ''T).
      
      Nested top-level splices
      ~~~~~~~~~~~~~~~~~~~~~~~~
      Previously TH would reject this, saying that splices cannot be nested:
      	f x = $(g $(h 'x))
      But there is no reason for this not to work.  First $(h 'x) is run,
      yielding code <blah> that is spliced instead of the $(h 'x). Then (g
      <blah>) is typechecked and run, yielding code that replaces the
      $(g ...) splice.  
      
      So this simply lifts the restriction.
      
      Fix Trac #3467: non-top-level type splices
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      
      It appears that when I added the ability to splice types in TH
      programs, I failed to pay attention to non-top-level splices -- that
      is, splices inside quotatation brackets.  
      
      This patch fixes the problem.  I had to modify HsType, so there's a
      knock-on change to Haddock.
      
      Its seems that a lot of lines of code has changed, but almost all the
      new lines are comments!
      
      General tidying up
      ~~~~~~~~~~~~~~~~~~
      As a result of thinking all this out I re-jigged the data type ThStage,
      which had far too many values before.  And I wrote a nice state transition
      diagram to make it all precise; 
         see Note [Template Haskell state diagram] in TcSplice
      
      Lots more refactoring in TcSplice, resulting in significantly less code.
      (A few more lines, but actually less code -- the rest is comments.)
      
      I think the result is significantly cleaner.
      1e436f2b
  13. 23 Jul, 2009 1 commit
    • simonpj@microsoft.com's avatar
      Add tuple sections as a new feature · 58521c72
      simonpj@microsoft.com authored
      This patch adds tuple sections, so that
      
      	(x,,z)  means   \y -> (x,y,z)
      
      Thanks for Max Bolinbroke for doing the hard work.
      
      In the end, instead of using two constructors in HsSyn, I used
      just one (still called ExplicitTuple) whose arguments can be
      	Present (LHsExpr id)
      or	Missing PostTcType
      
      While I was at it, I did a bit of refactoring too.
      58521c72
  14. 07 Jul, 2009 1 commit
  15. 06 Jul, 2009 1 commit
  16. 02 Jul, 2009 1 commit
    • simonpj@microsoft.com's avatar
      New syntax for GADT-style record declarations, and associated refactoring · 432b9c93
      simonpj@microsoft.com authored
      The main purpose of this patch is to fix Trac #3306, by fleshing out the
      syntax for GADT-style record declraations so that you have a context in 
      the type.  The new form is
         data T a where
           MkT :: forall a. Eq a => { x,y :: !a } -> T a
      See discussion on the Trac ticket.
      
      The old form is still allowed, but give a deprecation warning.
      
      When we remove the old form we'll also get rid of the one reduce/reduce
      error in the grammar. Hurrah!
      
      While I was at it, I failed as usual to resist the temptation to do lots of
      refactoring.  The parsing of data/type declarations is now much simpler and
      more uniform.  Less code, less chance of errors, and more functionality.
      Took longer than I planned, though.
      
      ConDecl has record syntax, but it was not being used consistently, so I
      pushed that through the compiler.
      432b9c93
  17. 26 Jun, 2009 1 commit
  18. 11 Jun, 2009 1 commit
  19. 27 May, 2009 1 commit
    • simonpj@microsoft.com's avatar
      Template Haskell: improve lifting for strings · 97a8fe87
      simonpj@microsoft.com authored
      When you have a (\s::String -> ....[| s |]....), the string 
      's' is lifted.  We used to get a chain of single-character 
      Cons nodes, correct but lots and lots of code.  
      
      This patch arranges to optimise that to a string literal. It does
      so in two places:
        a) In TcExpr, if we know that s::String, we generate liftString directly
        b) In DsMeta, if we find a list of character literals, we convert to
           a string.  This catches a few cases that (a) does not
      
      There an accompanying  patch in the template-haskell package, 
      adding Language.Haskell.TH.Syntax.liftString
      
      
      97a8fe87
  20. 26 Mar, 2009 2 commits
  21. 24 Mar, 2009 1 commit
  22. 19 Mar, 2009 2 commits
  23. 16 Dec, 2008 1 commit
    • Simon Marlow's avatar
      Rollback INLINE patches · e79c9ce0
      Simon Marlow authored
      rolling back:
      
      Fri Dec  5 16:54:00 GMT 2008  simonpj@microsoft.com
        * Completely new treatment of INLINE pragmas (big patch)
        
        This is a major patch, which changes the way INLINE pragmas work.
        Although lots of files are touched, the net is only +21 lines of
        code -- and I bet that most of those are comments!
        
        HEADS UP: interface file format has changed, so you'll need to
        recompile everything.
        
        There is not much effect on overall performance for nofib, 
        probably because those programs don't make heavy use of INLINE pragmas.
        
                Program           Size    Allocs   Runtime   Elapsed
                    Min         -11.3%     -6.9%     -9.2%     -8.2%
                    Max          -0.1%     +4.6%     +7.5%     +8.9%
         Geometric Mean          -2.2%     -0.2%     -1.0%     -0.8%
        
        (The +4.6% for on allocs is cichelli; see other patch relating to
        -fpass-case-bndr-to-join-points.)
        
        The old INLINE system
        ~~~~~~~~~~~~~~~~~~~~~
        The old system worked like this. A function with an INLINE pragam
        got a right-hand side which looked like
             f = __inline_me__ (\xy. e)
        The __inline_me__ part was an InlineNote, and was treated specially
        in various ways.  Notably, the simplifier didn't inline inside an
        __inline_me__ note.  
        
        As a result, the code for f itself was pretty crappy. That matters
        if you say (map f xs), because then you execute the code for f,
        rather than inlining a copy at the call site.
        
        The new story: InlineRules
        ~~~~~~~~~~~~~~~~~~~~~~~~~~
        The new system removes the InlineMe Note altogether.  Instead there
        is a new constructor InlineRule in CoreSyn.Unfolding.  This is a 
        bit like a RULE, in that it remembers the template to be inlined inside
        the InlineRule.  No simplification or inlining is done on an InlineRule,
        just like RULEs.  
        
        An Id can have an InlineRule *or* a CoreUnfolding (since these are two
        constructors from Unfolding). The simplifier treats them differently:
        
          - An InlineRule is has the substitution applied (like RULES) but 
            is otherwise left undisturbed.
        
          - A CoreUnfolding is updated with the new RHS of the definition,
            on each iteration of the simplifier.
        
        An InlineRule fires regardless of size, but *only* when the function
        is applied to enough arguments.  The "arity" of the rule is specified
        (by the programmer) as the number of args on the LHS of the "=".  So
        it makes a difference whether you say
          	{-# INLINE f #-}
        	f x = \y -> e     or     f x y = e
        This is one of the big new features that InlineRule gives us, and it
        is one that Roman really wanted.
        
        In contrast, a CoreUnfolding can fire when it is applied to fewer
        args than than the function has lambdas, provided the result is small
        enough.
        
        
        Consequential stuff
        ~~~~~~~~~~~~~~~~~~~
        * A 'wrapper' no longer has a WrapperInfo in the IdInfo.  Instead,
          the InlineRule has a field identifying wrappers.
        
        * Of course, IfaceSyn and interface serialisation changes appropriately.
        
        * Making implication constraints inline nicely was a bit fiddly. In
          the end I added a var_inline field to HsBInd.VarBind, which is why
          this patch affects the type checker slightly
        
        * I made some changes to the way in which eta expansion happens in
          CorePrep, mainly to ensure that *arguments* that become let-bound
          are also eta-expanded.  I'm still not too happy with the clarity
          and robustness fo the result.
        
        * We now complain if the programmer gives an INLINE pragma for
          a recursive function (prevsiously we just ignored it).  Reason for
          change: we don't want an InlineRule on a LoopBreaker, because then
          we'd have to check for loop-breaker-hood at occurrence sites (which
          isn't currenlty done).  Some tests need changing as a result.
        
        This patch has been in my tree for quite a while, so there are
        probably some other minor changes.
        
      
          M ./compiler/basicTypes/Id.lhs -11
          M ./compiler/basicTypes/IdInfo.lhs -82
          M ./compiler/basicTypes/MkId.lhs -2 +2
          M ./compiler/coreSyn/CoreFVs.lhs -2 +25
          M ./compiler/coreSyn/CoreLint.lhs -5 +1
          M ./compiler/coreSyn/CorePrep.lhs -59 +53
          M ./compiler/coreSyn/CoreSubst.lhs -22 +31
          M ./compiler/coreSyn/CoreSyn.lhs -66 +92
          M ./compiler/coreSyn/CoreUnfold.lhs -112 +112
          M ./compiler/coreSyn/CoreUtils.lhs -185 +184
          M ./compiler/coreSyn/MkExternalCore.lhs -1
          M ./compiler/coreSyn/PprCore.lhs -4 +40
          M ./compiler/deSugar/DsBinds.lhs -70 +118
          M ./compiler/deSugar/DsForeign.lhs -2 +4
          M ./compiler/deSugar/DsMeta.hs -4 +3
          M ./compiler/hsSyn/HsBinds.lhs -3 +3
          M ./compiler/hsSyn/HsUtils.lhs -2 +7
          M ./compiler/iface/BinIface.hs -11 +25
          M ./compiler/iface/IfaceSyn.lhs -13 +21
          M ./compiler/iface/MkIface.lhs -24 +19
          M ./compiler/iface/TcIface.lhs -29 +23
          M ./compiler/main/TidyPgm.lhs -55 +49
          M ./compiler/parser/ParserCore.y -5 +6
          M ./compiler/simplCore/CSE.lhs -2 +1
          M ./compiler/simplCore/FloatIn.lhs -6 +1
          M ./compiler/simplCore/FloatOut.lhs -23
          M ./compiler/simplCore/OccurAnal.lhs -36 +5
          M ./compiler/simplCore/SetLevels.lhs -59 +54
          M ./compiler/simplCore/SimplCore.lhs -48 +52
          M ./compiler/simplCore/SimplEnv.lhs -26 +22
          M ./compiler/simplCore/SimplUtils.lhs -28 +4
          M ./compiler/simplCore/Simplify.lhs -91 +109
          M ./compiler/specialise/Specialise.lhs -15 +18
          M ./compiler/stranal/WorkWrap.lhs -14 +11
          M ./compiler/stranal/WwLib.lhs -2 +2
          M ./compiler/typecheck/Inst.lhs -1 +3
          M ./compiler/typecheck/TcBinds.lhs -17 +27
          M ./compiler/typecheck/TcClassDcl.lhs -1 +2
          M ./compiler/typecheck/TcExpr.lhs -4 +6
          M ./compiler/typecheck/TcForeign.lhs -1 +1
          M ./compiler/typecheck/TcGenDeriv.lhs -14 +13
          M ./compiler/typecheck/TcHsSyn.lhs -3 +2
          M ./compiler/typecheck/TcInstDcls.lhs -5 +4
          M ./compiler/typecheck/TcRnDriver.lhs -2 +11
          M ./compiler/typecheck/TcSimplify.lhs -10 +17
          M ./compiler/vectorise/VectType.hs +7
      
      Mon Dec  8 12:43:10 GMT 2008  simonpj@microsoft.com
        * White space only
      
          M ./compiler/simplCore/Simplify.lhs -2
      
      Mon Dec  8 12:48:40 GMT 2008  simonpj@microsoft.com
        * Move simpleOptExpr from CoreUnfold to CoreSubst
      
          M ./compiler/coreSyn/CoreSubst.lhs -1 +87
          M ./compiler/coreSyn/CoreUnfold.lhs -72 +1
      
      Mon Dec  8 17:30:18 GMT 2008  simonpj@microsoft.com
        * Use CoreSubst.simpleOptExpr in place of the ad-hoc simpleSubst (reduces code too)
      
          M ./compiler/deSugar/DsBinds.lhs -50 +16
      
      Tue Dec  9 17:03:02 GMT 2008  simonpj@microsoft.com
        * Fix Trac #2861: bogus eta expansion
        
        Urghlhl!  I "tided up" the treatment of the "state hack" in CoreUtils, but
        missed an unexpected interaction with the way that a bottoming function
        simply swallows excess arguments.  There's a long
             Note [State hack and bottoming functions]
        to explain (which accounts for most of the new lines of code).
        
      
          M ./compiler/coreSyn/CoreUtils.lhs -16 +53
      
      Mon Dec 15 10:02:21 GMT 2008  Simon Marlow <marlowsd@gmail.com>
        * Revert CorePrep part of "Completely new treatment of INLINE pragmas..."
        
        The original patch said:
        
        * I made some changes to the way in which eta expansion happens in
          CorePrep, mainly to ensure that *arguments* that become let-bound
          are also eta-expanded.  I'm still not too happy with the clarity
          and robustness fo the result.
          
        Unfortunately this change apparently broke some invariants that were
        relied on elsewhere, and in particular lead to panics when compiling
        with profiling on.
        
        Will re-investigate in the new year.
      
          M ./compiler/coreSyn/CorePrep.lhs -53 +58
          M ./configure.ac -1 +1
      
      Mon Dec 15 12:28:51 GMT 2008  Simon Marlow <marlowsd@gmail.com>
        * revert accidental change to configure.ac
      
          M ./configure.ac -1 +1
      e79c9ce0
  24. 05 Dec, 2008 1 commit
    • simonpj@microsoft.com's avatar
      Completely new treatment of INLINE pragmas (big patch) · d95ce839
      simonpj@microsoft.com authored
      This is a major patch, which changes the way INLINE pragmas work.
      Although lots of files are touched, the net is only +21 lines of
      code -- and I bet that most of those are comments!
      
      HEADS UP: interface file format has changed, so you'll need to
      recompile everything.
      
      There is not much effect on overall performance for nofib, 
      probably because those programs don't make heavy use of INLINE pragmas.
      
              Program           Size    Allocs   Runtime   Elapsed
                  Min         -11.3%     -6.9%     -9.2%     -8.2%
                  Max          -0.1%     +4.6%     +7.5%     +8.9%
       Geometric Mean          -2.2%     -0.2%     -1.0%     -0.8%
      
      (The +4.6% for on allocs is cichelli; see other patch relating to
      -fpass-case-bndr-to-join-points.)
      
      The old INLINE system
      ~~~~~~~~~~~~~~~~~~~~~
      The old system worked like this. A function with an INLINE pragam
      got a right-hand side which looked like
           f = __inline_me__ (\xy. e)
      The __inline_me__ part was an InlineNote, and was treated specially
      in various ways.  Notably, the simplifier didn't inline inside an
      __inline_me__ note.  
      
      As a result, the code for f itself was pretty crappy. That matters
      if you say (map f xs), because then you execute the code for f,
      rather than inlining a copy at the call site.
      
      The new story: InlineRules
      ~~~~~~~~~~~~~~~~~~~~~~~~~~
      The new system removes the InlineMe Note altogether.  Instead there
      is a new constructor InlineRule in CoreSyn.Unfolding.  This is a 
      bit like a RULE, in that it remembers the template to be inlined inside
      the InlineRule.  No simplification or inlining is done on an InlineRule,
      just like RULEs.  
      
      An Id can have an InlineRule *or* a CoreUnfolding (since these are two
      constructors from Unfolding). The simplifier treats them differently:
      
        - An InlineRule is has the substitution applied (like RULES) but 
          is otherwise left undisturbed.
      
        - A CoreUnfolding is updated with the new RHS of the definition,
          on each iteration of the simplifier.
      
      An InlineRule fires regardless of size, but *only* when the function
      is applied to enough arguments.  The "arity" of the rule is specified
      (by the programmer) as the number of args on the LHS of the "=".  So
      it makes a difference whether you say
        	{-# INLINE f #-}
      	f x = \y -> e     or     f x y = e
      This is one of the big new features that InlineRule gives us, and it
      is one that Roman really wanted.
      
      In contrast, a CoreUnfolding can fire when it is applied to fewer
      args than than the function has lambdas, provided the result is small
      enough.
      
      
      Consequential stuff
      ~~~~~~~~~~~~~~~~~~~
      * A 'wrapper' no longer has a WrapperInfo in the IdInfo.  Instead,
        the InlineRule has a field identifying wrappers.
      
      * Of course, IfaceSyn and interface serialisation changes appropriately.
      
      * Making implication constraints inline nicely was a bit fiddly. In
        the end I added a var_inline field to HsBInd.VarBind, which is why
        this patch affects the type checker slightly
      
      * I made some changes to the way in which eta expansion happens in
        CorePrep, mainly to ensure that *arguments* that become let-bound
        are also eta-expanded.  I'm still not too happy with the clarity
        and robustness fo the result.
      
      * We now complain if the programmer gives an INLINE pragma for
        a recursive function (prevsiously we just ignored it).  Reason for
        change: we don't want an InlineRule on a LoopBreaker, because then
        we'd have to check for loop-breaker-hood at occurrence sites (which
        isn't currenlty done).  Some tests need changing as a result.
      
      This patch has been in my tree for quite a while, so there are
      probably some other minor changes.
      d95ce839
  25. 03 Oct, 2008 1 commit
  26. 07 Aug, 2008 1 commit
  27. 31 Jul, 2008 1 commit
  28. 07 May, 2008 1 commit
  29. 06 May, 2008 2 commits
    • Ian Lynagh's avatar
      5664dcac
    • simonpj@microsoft.com's avatar
      Fix Trac #2246; overhaul handling of overloaded literals · ecdaf6bc
      simonpj@microsoft.com authored
      The real work of fixing Trac #2246 is to use shortCutLit in
      MatchLit.dsOverLit, so that type information discovered late in the
      day by the type checker can still be exploited during desugaring.
      
      However, as usual I found myself doing some refactoring along the
      way, to tidy up the handling of overloaded literals.   The main
      change is to split HsOverLit into a record, which in turn uses
      a sum type for the three variants.  This makes the code significantly
      more modular.
      
      data HsOverLit id
        = OverLit {
      	ol_val :: OverLitVal, 
      	ol_rebindable :: Bool,		-- True <=> rebindable syntax
      					-- False <=> standard syntax
      	ol_witness :: SyntaxExpr id,	-- Note [Overloaded literal witnesses]
      	ol_type :: PostTcType }
      
      data OverLitVal
        = HsIntegral   !Integer   	-- Integer-looking literals;
        | HsFractional !Rational   	-- Frac-looking literals
        | HsIsString   !FastString 	-- String-looking literals
      ecdaf6bc
  30. 04 May, 2008 1 commit
  31. 23 Apr, 2008 1 commit
  32. 12 Apr, 2008 1 commit
  33. 18 Jan, 2008 1 commit
    • simonpj@microsoft.com's avatar
      Add quasi-quotation, courtesy of Geoffrey Mainland · f3399c44
      simonpj@microsoft.com authored
      This patch adds quasi-quotation, as described in
        "Nice to be Quoted: Quasiquoting for Haskell"
      	(Geoffrey Mainland, Haskell Workshop 2007)
      Implemented by Geoffrey and polished by Simon.
      
      Overview
      ~~~~~~~~
      The syntax for quasiquotation is very similar to the existing
      Template haskell syntax:
      	[$q| stuff |]
      where 'q' is the "quoter".  This syntax differs from the paper, by using
      a '$' rather than ':', to avoid clashing with parallel array comprehensions.
       
      The "quoter" is a value of type Language.Haskell.TH.Quote.QuasiQuoter, which
      contains two functions for quoting expressions and patterns, respectively.
       
           quote = Language.Haskell.TH.Quote.QuasiQuoter quoteExp quotePat
       
           quoteExp :: String -> Language.Haskell.TH.ExpQ
           quotePat :: String -> Language.Haskell.TH.PatQ
      
      TEXT is passed unmodified to the quoter. The context of the
      quasiquotation statement determines which of the two quoters is
      called: if the quasiquotation occurs in an expression context,
      quoteExp is called, and if it occurs in a pattern context, quotePat
      is called.
      
      The result of running the quoter on its arguments is spliced into
      the program using Template Haskell's existing mechanisms for
      splicing in code. Note that although Template Haskell does not
      support pattern brackets, with this patch binding occurrences of
      variables in patterns are supported. Quoters must also obey the same
      stage restrictions as Template Haskell; in particular, in this
      example quote may not be defined in the module where it is used as a
      quasiquoter, but must be imported from another module.
      
      Points to notice
      ~~~~~~~~~~~~~~~~
      * The whole thing is enabled with the flag -XQuasiQuotes
      
      * There is an accompanying patch to the template-haskell library. This
        involves one interface change:
      	currentModule :: Q String
        is replaced by
      	location :: Q Loc
        where Loc is a data type defined in TH.Syntax thus:
            data Loc
              = Loc { loc_filename :: String
      	      , loc_package  :: String
      	      , loc_module   :: String
      	      , loc_start    :: CharPos
      	      , loc_end      :: CharPos }
      
            type CharPos = (Int, Int)	-- Line and character position
       
        So you get a lot more info from 'location' than from 'currentModule'.
        The location you get is the location of the splice.
        
        This works in Template Haskell too of course, and lets a TH program
        generate much better error messages.
      
      * There's also a new module in the template-haskell package called 
        Language.Haskell.TH.Quote, which contains support code for the
        quasi-quoting feature.
      
      * Quasi-quote splices are run *in the renamer* because they can build 
        *patterns* and hence the renamer needs to see the output of running the
        splice.  This involved a bit of rejigging in the renamer, especially
        concerning the reporting of duplicate or shadowed names.
      
        (In fact I found and removed a few calls to checkDupNames in RnSource 
        that are redundant, becuase top-level duplicate decls are handled in
        RnNames.)
      
      
      f3399c44
  34. 16 Jan, 2008 1 commit
  35. 10 Oct, 2007 1 commit
    • Dan Licata's avatar
      View patterns, record wildcards, and record puns · 6a05ec5e
      Dan Licata authored
      This patch implements three new features:
      * view patterns (syntax: expression -> pat in a pattern)
      * working versions of record wildcards and record puns
      See the manual for detailed descriptions.
      
      Other minor observable changes:
      * There is a check prohibiting local fixity declarations
        when the variable being fixed is not defined in the same let
      * The warn-unused-binds option now reports warnings for do and mdo stmts
      
      Implementation notes: 
      
      * The pattern renamer is now in its own module, RnPat, and the
      implementation is now in a CPS style so that the correct context is
      delivered to pattern expressions.
      
      * These features required a fairly major upheaval to the renamer.
      Whereas the old version used to collect up all the bindings from a let
      (or top-level, or recursive do statement, ...) and put them into scope
      before renaming anything, the new version does the collection as it
      renames.  This allows us to do the right thing with record wildcard
      patterns (which need to be expanded to see what names should be
      collected), and it allows us to implement the desired semantics for view
      patterns in lets.  This change had a bunch of domino effects brought on
      by fiddling with the top-level renaming.
      
      * Prior to this patch, there was a tricky bug in mkRecordSelId in HEAD,
      which did not maintain the invariant necessary for loadDecl.  See note
      [Tricky iface loop] for details.
      6a05ec5e
  36. 04 Sep, 2007 1 commit