1. 16 Oct, 2000 1 commit
  2. 13 Oct, 2000 1 commit
  3. 11 Oct, 2000 1 commit
  4. 03 Oct, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-10-03 08:43:00 by simonpj] · 710e2074
      simonpj authored
      --------------------------------------
      	Adding generics		SLPJ Oct 2000
      	--------------------------------------
      
      This big commit adds Hinze/PJ-style generic class definitions, based
      on work by Andrei Serjantov.  For example:
      
        class Bin a where
          toBin   :: a -> [Int]
          fromBin :: [Int] -> (a, [Int])
      
          toBin {| Unit |}    Unit	  = []
          toBin {| a :+: b |} (Inl x)   = 0 : toBin x
          toBin {| a :+: b |} (Inr y)   = 1 : toBin y
          toBin {| a :*: b |} (x :*: y) = toBin x ++ toBin y
      
      
          fromBin {| Unit |}    bs      = (Unit, bs)
          fromBin {| a :+: b |} (0:bs)  = (Inl x, bs')    where (x,bs') = fromBin bs
          fromBin {| a :+: b |} (1:bs)  = (Inr y, bs')    where (y,bs') = fromBin bs
          fromBin {| a :*: b |} bs  	  = (x :*: y, bs'') where (x,bs' ) = fromBin bs
      							  (y,bs'') = fromBin bs'
      
      Now we can say simply
      
        instance Bin a => Bin [a]
      
      and the compiler will derive the appropriate code automatically.
      
      		(About 9k lines of diffs.  Ha!)
      
      
      Generic related things
      ~~~~~~~~~~~~~~~~~~~~~~
      
      * basicTypes/BasicTypes: The EP type (embedding-projection pairs)
      
      * types/TyCon:
      	An extra field in an algebraic tycon (genInfo)
      
      * types/Class, and hsSyn/HsBinds:
      	Each class op (or ClassOpSig) carries information about whether
      	it  	a) has no default method
      		b) has a polymorphic default method
      		c) has a generic default method
      	There's a new data type for this: Class.DefMeth
      
      * types/Generics:
      	A new module containing good chunk of the generic-related code
      	It has a .hi-boot file (alas).
      
      * typecheck/TcInstDcls, typecheck/TcClassDcl:
      	Most of the rest of the generics-related code
      
      * hsSyn/HsTypes:
      	New infix type form to allow types of the form
      		data a :+: b = Inl a | Inr b
      
      * parser/Parser.y, Lex.lhs, rename/ParseIface.y:
      	Deal with the new syntax
      
      * prelude/TysPrim, TysWiredIn:
      	Need to generate generic stuff for the wired-in TyCons
      
      * rename/RnSource RnBinds:
      	A rather gruesome hack to deal with scoping of type variables
      	from a generic patterns.  Details commented in the ClassDecl
      	case of RnSource.rnDecl.
      
      	Of course, there are many minor renamer consequences of the
      	other changes above.
      
      * lib/std/PrelBase.lhs
      	Data type declarations for Unit, :+:, :*:
      
      
      Slightly unrelated housekeeping
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * hsSyn/HsDecls:
      	ClassDecls now carry the Names for their implied declarations
      	(superclass selectors, tycon, etc) in a list, rather than
      	laid out one by one.  This simplifies code between the parser
      	and the type checker.
      
      * prelude/PrelNames, TysWiredIn:
      	All the RdrNames are now together in PrelNames.
      
      * utils/ListSetOps:
      	Add finite mappings based on equality and association lists (Assoc a b)
      	Move stuff from List.lhs that is related
      710e2074
  5. 22 Sep, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-09-22 15:56:12 by simonpj] · 1bba522f
      simonpj authored
      --------------------------------------------------
      	Tidying up HsLit, and making it possible to define
      		your own numeric library
      
      		Simon PJ 22 Sept 00
      	--------------------------------------------------
      
      ** NOTE: I did these changes on the aeroplane.  They should compile,
      	 and the Prelude still compiles OK, but it's entirely 
      	 possible that I've broken something
      
      The original reason for this many-file but rather shallow
      commit is that it's impossible in Haskell to write your own
      numeric library.  Why?  Because when you say '1' you get 
      (Prelude.fromInteger 1), regardless of what you hide from the
      Prelude, or import from other libraries you have written.  So the
      idea is to extend the -fno-implicit-prelude flag so that 
      in addition to no importing the Prelude, you can rebind 
      	fromInteger	-- Applied to literal constants
      	fromRational	-- Ditto
      	negate		-- Invoked by the syntax (-x)
      	the (-) used when desugaring n+k patterns
      
      After toying with other designs, I eventually settled on a simple,
      crude one: rather than adding a new flag, I just extended the
      semantics of -fno-implicit-prelude so that uses of fromInteger,
      fromRational and negate are all bound to "whatever is in scope" 
      rather than "the fixed Prelude functions".  So if you say
      
      	{-# OPTIONS -fno-implicit-prelude #-}
      	module M where
       	import MyPrelude( fromInteger )
      
      	x = 3
      
      the literal 3 will use whatever (unqualified) "fromInteger" is in scope,
      in this case the one gotten from MyPrelude.
      
      
      On the way, though, I studied how HsLit worked, and did a substantial tidy
      up, deleting quite a lot of code along the way.  In particular.
      
      * HsBasic.lhs is renamed HsLit.lhs.  It defines the HsLit type.
      
      * There are now two HsLit types, both defined in HsLit.
      	HsLit for non-overloaded literals (like 'x')
      	HsOverLit for overloaded literals (like 1 and 2.3)
      
      * HsOverLit completely replaces Inst.OverloadedLit, which disappears.
        An HsExpr can now be an HsOverLit as well as an HsLit.
      
      * HsOverLit carries the Name of the fromInteger/fromRational operation,
        so that the renamer can help with looking up the unqualified name 
        when -fno-implicit-prelude is on.  Ditto the HsExpr for negation.
        It's all very tidy now.
      
      * RdrHsSyn contains the stuff that handles -fno-implicit-prelude
        (see esp RdrHsSyn.prelQual).  RdrHsSyn also contains all the "smart constructors"
        used by the parser when building HsSyn.  See for example RdrHsSyn.mkNegApp
        (previously the renamer (!) did the business of turning (- 3#) into -3#).
      
      * I tidied up the handling of "special ids" in the parser.  There's much
        less duplication now.
      
      * Move Sven's Horner stuff to the desugarer, where it belongs.  
        There's now a nice function DsUtils.mkIntegerLit which brings together
        related code from no fewer than three separate places into one single
        place.  Nice!
      
      * A nice tidy-up in MatchLit.partitionEqnsByLit became possible.
      
      * Desugaring of HsLits is now much tidier (DsExpr.dsLit)
      
      * Some stuff to do with RdrNames is moved from ParseUtil.lhs to RdrHsSyn.lhs,
        which is where it really belongs.
      
      * I also removed 
      	many unnecessary imports from modules 
      	quite a bit of dead code
        in divers places
      1bba522f
  6. 14 Sep, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-09-14 13:46:39 by simonpj] · cae34044
      simonpj authored
      ---------------------------------------
      	Simon's tuning changes: early Sept 2000
      	---------------------------------------
      
      Library changes
      ~~~~~~~~~~~~~~~
      * Eta expand PrelShow.showLitChar.  It's impossible to compile this well,
        and it makes a big difference to some programs (e.g. gen_regexps)
      
      * Make PrelList.concat into a good producer (in the foldr/build sense)
      
      
      Flag changes
      ~~~~~~~~~~~~
      * Add -ddump-hi-diffs to print out changes in interface files.  Useful
        when watching what the compiler is doing
      
      * Add -funfolding-update-in-place to enable the experimental optimisation
        that makes the inliner a bit keener to inline if it's in the RHS of
        a thunk that might be updated in place.  Sometimes this is a bad idea
        (one example is in spectral/sphere; see notes in nofib/Simon-nofib-notes)
      
      
      Tuning things
      ~~~~~~~~~~~~~
      * Fix a bug in SetLevels.lvlMFE.  (change ctxt_lvl to dest_level)
        I don't think this has any performance effect, but it saves making
        a redundant let-binding that is later eliminated.
      
      * Desugar.dsProgram and DsForeign
        Glom together all the bindings into a single Rec.  Previously the
        bindings generated by 'foreign' declarations were not glommed together, but
        this led to an infelicity (i.e. poorer code than necessary) in the modules
        that actually declare Float and Double (explained a bit more in Desugar.dsProgram)
      
      * OccurAnal.shortMeOut and IdInfo.shortableIdInfo
        Don't do the occurrence analyser's shorting out stuff for things which
        have rules.  Comments near IdInfo.shortableIdInfo.
        This is deeply boring, and mainly to do with making rules work well.
        Maybe rules should have phases attached too....
      
      * CprAnalyse.addIdCprInfo
        Be a bit more willing to add CPR information to thunks;
        in particular, if the strictness analyser has just discovered that this
        is a strict let, then the let-to-case transform will happen, and CPR is fine.
        This made a big difference to PrelBase.modInt, which had something like
      	modInt = \ x -> let r = ... -> I# v in
      			...body strict in r...
        r's RHS isn't a value yet; but modInt returns r in various branches, so
        if r doesn't have the CPR property then neither does modInt
      
      * MkId.mkDataConWrapId
        Arrange that vanilla constructors, like (:) and I#, get unfoldings that are
        just a simple variable $w:, $wI#.  This ensures they'll be inlined even into
        rules etc, which makes matching a bit more reliable.  The downside is that in
        situations like (map (:) xs), we'll end up with (map (\y ys. $w: y ys) xs.
        Which is tiresome but it doesn't happen much.
      
      * SaAbsInt.findStrictness
        Deal with the case where a thing with no arguments is bottom.  This is Good.
        E.g.   module M where { foo = error "help" }
        Suppose we have in another module
      	case M.foo of ...
        Then we'd like to do the case-of-error transform, without inlining foo.
      
      
      Tidying up things
      ~~~~~~~~~~~~~~~~~
      * Reorganised Simplify.completeBinding (again).
      
      * Removed the is_bot field in CoreUnfolding (is_cheap is true if is_bot is!)
        This is just a tidy up
      
      * HsDecls and others
        Remove the NewCon constructor from ConDecl.  It just added code, and nothing else.
        And it led to a bug in MkIface, which though that a newtype decl was always changing!
      
      * IdInfo and many others
        Remove all vestiges of UpdateInfo (hasn't been used for years)
      cae34044
  7. 01 Aug, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-08-01 09:08:25 by simonpj] · fe69f3c1
      simonpj authored
      Simon's Marktoberdorf Commits
      
      1.  Tidy up the renaming story for "system binders", such as
      dictionary functions, default methods, constructor workers etc.  These
      are now documented in HsDecls.  The main effect of the change, apart
      from tidying up, is to make the *type-checker* (instead of the
      renamer) generate names for dict-funs and default-methods.  This is
      good because Sergei's generic-class stuff generates new classes at
      typecheck time.
      
      
      2.  Fix the CSE pass so it does not require the no-shadowing invariant.
      Keith discovered that the simplifier occasionally returns a result
      with shadowing.  After much fiddling around (which has improved the
      code in the simplifier a bit) I found that it is nearly impossible to
      arrange that it really does do no-shadowing.  So I gave up and fixed
      the CSE pass (which is the only one to rely on it) instead.
      
      
      3. Fix a performance bug in the simplifier.  The change is in
      SimplUtils.interestingArg.  It computes whether an argment should 
      be considered "interesting"; if a function is applied to an interesting
      argument, we are more likely to inline that function.
      Consider this case
      	let x = 3 in f x
      The 'x' argument was considered "uninteresting" for a silly reason.
      Since x only occurs once, it was unconditionally substituted, but
      interestingArg didn't take account of that case.  Now it does.
      
      I also made interestingArg a bit more liberal.  Let's see if we
      get too much inlining now.
      
      
      4.  In the occurrence analyser, we were choosing a bad loop breaker.
      Here's the comment that's now in OccurAnal.reOrderRec
      
          score ((bndr, rhs), _, _)
      	| exprIsTrivial rhs 	   = 3	-- Practically certain to be inlined
      		-- Used to have also: && not (isExportedId bndr)
      		-- But I found this sometimes cost an extra iteration when we have
      		--	rec { d = (a,b); a = ...df...; b = ...df...; df = d }
      		-- where df is the exported dictionary. Then df makes a really
      		-- bad choice for loop breaker
      
      I also increased the score for bindings with a non-functional type, so that
      dictionaries have a better chance of getting inlined early
      
      
      5. Add a hash code to the InScopeSet (and make it properly abstract)
      This should make uniqAway a lot more robust.  Simple experiments suggest
      that uniqAway no longer gets into the long iteration chains that it used
      to.
      
      
      6.  Fix a bug in the inliner that made the simplifier tend to get into
      a loop where it would keep iterating ("4 iterations, bailing out" message).
      In SimplUtils.mkRhsTyLam we float bindings out past a big lambda, thus:
      	x = /\ b -> let g = \x -> f x x
      		    in E
      becomes
      	g* = /\a -> \x -> f x x
      	x = /\ b -> let g = g* b in E
      	
      It's essential that we don't simply inling g* back into the RHS of g,
      else we will be back to square 1.  The inliner is meant not to do this
      because there's no benefit to the inlining, but the size calculation
      was a little off in CoreUnfold.
      
      
      7.  In SetLevels we were bogus-ly building a Subst with an empty in-scope
      set, so a WARNING popped up when compiling some modules.  (knights/ChessSetList
      was the example that tickled it.)  Now in fact the warning wasn't an error,
      but the Right Thing to do is to carry down a proper Subst in SetLevels, so
      that is what I have now done.  It is very little more expensive.
      fe69f3c1
  8. 14 Jul, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-07-14 08:17:36 by simonpj] · 77a8c0db
      simonpj authored
      This commit completely re-does the kind-inference mechanism.
      Previously it was inter-wound with type inference, but that was
      always hard to understand, and it finally broke when we started
      checking for ambiguity when type-checking a type signature (details
      irrelevant).
      
      So now kind inference is more clearly separated, so that it never
      takes place at the same time as type inference.  The biggest change
      is in TcTyClsDecls, which does the kind inference for a group of
      type and class declarations.  It now contains comments to explain
      how it all works.
      
      There are also comments in TypeRep which describes the slightly
      tricky way in which we deal with the fact that kind 'type' (written
      '*') actually has 'boxed type' and 'unboxed type' as sub-kinds.
      The whole thing is a bit of a hack, because we don't really have 
      sub-kinding, but it's less of a hack than before.
      
      A lot of general tidying up happened at the same time.
      In particular, I removed some dead code here and there
      77a8c0db
  9. 11 Jul, 2000 1 commit
  10. 06 Jul, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-07-06 16:31:45 by simonpj] · 525898a9
      simonpj authored
      * Improve the warning "M is imported but nothing from it is used"
        In particular, don't warn if some instances from it are imported.
      
        It's pretty much impossible to do the Right Thing always.
        A comment in Rename.lhs says
      	-- NOTE: Consider
      	--	      module This
      	--		import M ()
      	--
      	--	 The import M() is not *necessarily* redundant, even if
      	-- 	 we suck in no instance decls from M (e.g. it contains
      	--	 no instance decls, or This contains no code).  It may be
      	--	 that we import M solely to ensure that M's orphan instance
      	--	 decls (or those in its imports) are visible to people who
      	--	 import This.  Sigh.
      	--	 There's really no good way to detect this, so the error message
      	--	 in RnEnv.warnUnusedModules is weakened instead
      
      * Minor comment changes to RnIfaces.lhs
      
      * Use NameEnv instead of UFM in TcEnv (tidy up only)
      525898a9
  11. 25 May, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-05-25 12:41:14 by simonpj] · 495ef8bd
      simonpj authored
      ~~~~~~~~~~~~
      		Apr/May 2000
      		~~~~~~~~~~~~
      
      This is a pretty big commit!  It adds stuff I've been working on
      over the last month or so.  DO NOT MERGE IT WITH 4.07!
      
      Interface file formats have changed a little; you'll need
      to make clean before remaking.
      
      						Simon PJ
      
      Recompilation checking
      ~~~~~~~~~~~~~~~~~~~~~~
      Substantial improvement in recompilation checking.  The version management
      is now entirely internal to GHC.  ghc-iface.lprl is dead!
      
      The trick is to generate the new interface file in two steps:
        - first convert Types etc to HsTypes etc, and thereby
      	build a new ParsedIface
        - then compare against the parsed (but not renamed) version of the old
      	interface file
      Doing this meant adding code to convert *to* HsSyn things, and to
      compare HsSyn things for equality.  That is the main tedious bit.
      
      Another improvement is that we now track version info for
      fixities and rules, which was missing before.
      
      
      Interface file reading
      ~~~~~~~~~~~~~~~~~~~~~~
      Make interface files reading more robust.
        * If the old interface file is unreadable, don't fail. [bug fix]
      
        * If the old interface file mentions interfaces
          that are unreadable, don't fail. [bug fix]
      
        * When we can't find the interface file,
          print the directories we are looking in.  [feature]
      
      
      Type signatures
      ~~~~~~~~~~~~~~~
        * New flag -ddump-types to print type signatures
      
      
      Type pruning
      ~~~~~~~~~~~~
      When importing
      	data T = T1 A | T2 B | T3 C
      it seems excessive to import the types A, B, C as well, unless
      the constructors T1, T2 etc are used.  A,B,C might be more types,
      and importing them may mean reading more interfaces, and so on.
       So the idea is that the renamer will just import the decl
      	data T
      unless one of the constructors is used.  This turns out to be quite
      easy to implement.  The downside is that we must make sure the
      constructors are always available if they are really needed, so
      I regard this as an experimental feature.
      
      
      Elimininate ThinAir names
      ~~~~~~~~~~~~~~~~~~~~~~~~~
      Eliminate ThinAir.lhs and all its works.  It was always a hack, and now
      the desugarer carries around an environment I think we can nuke ThinAir
      altogether.
      
      As part of this, I had to move all the Prelude RdrName defns from PrelInfo
      to PrelMods --- so I renamed PrelMods as PrelNames.
      
      I also had to move the builtinRules so that they are injected by the renamer
      (rather than appearing out of the blue in SimplCore).  This is if anything simpler.
      
      Miscellaneous
      ~~~~~~~~~~~~~
      * Tidy up the data types involved in Rules
      
      * Eliminate RnEnv.better_provenance; use Name.hasBetterProv instead
      
      * Add Unique.hasKey :: Uniquable a => a -> Unique -> Bool
        It's useful in a lot of places
      
      * Fix a bug in interface file parsing for __U[!]
      495ef8bd
  12. 10 May, 2000 1 commit
  13. 08 May, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-05-08 07:14:35 by simonpj] · cf58efc1
      simonpj authored
      Interface file reading
      ~~~~~~~~~~~~~~~~~~~~~~
      Make interface files reading more robust.  
        * If the old interface file is unreadable, don't fail. [bug fix]
      
        * If the old interface file mentions interfaces 
          that are unreadable, don't fail. [bug fix]
      
        * When we can't find the interface file, 
          print the directories we are looking in.  [feature]
      cf58efc1
  14. 13 Apr, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-04-13 11:56:35 by simonpj] · 9579283c
      simonpj authored
      Add support for 'packages'.
      
      * A package is a group of modules.
      
      * A package has a name (e.g. std)
      
      * A package is built into a single library (Unix; e.g. libHSstd.a)
                             or a single DLL     (Windows; e.g. HSstd.dll)
      
      * The '-package-name foo' flag tells GHC that the module being compiled
        is destined for package foo.
      
      * The '-package foo' flag tells GHC to make available modules
        from package 'foo'.  It replaces '-syslib foo' which is now deprecated.
      
      * Cross-package references cost an extra indirection in Windows,
        but not Unix
      
      * GHC does not maintain detailed cross-package dependency information.
        It does remember which modules in other packages the current module
        depends on, but not which things within those imported things.
      
      
      All of this tidies up the Prelude enormously.  The Prelude and
      Standard Libraries are built into a singl package called 'std'.  (This
      is a change; the library is now called libHSstd.a instead of libHS.a)
      9579283c
  15. 07 Apr, 2000 2 commits
    • simonpj's avatar
      [project @ 2000-04-07 15:24:15 by simonpj] · 5f990952
      simonpj authored
      * Make it so that interface files track dependencies on
        all modules except Prelude modules.
        (Was "library" modules, distinguished by a gross hack
         but that messed up StgHugs.)
      5f990952
    • simonpj's avatar
      [project @ 2000-04-07 13:45:46 by simonpj] · cfbedcec
      simonpj authored
      * Fix 'foreign export' and 'foreign export dynamic' so
        that we can export pure (non-IO) functions as well as IO-ish ones
      
        NB: There's a change to PrelIOBase, so you'll
            need to recompile the Prelude
      
      * Add Type.mkDictTys and call it in various places.
      cfbedcec
  16. 27 Mar, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-03-27 16:22:09 by simonpj] · 783e505e
      simonpj authored
      Fix a bug in import listing in interface files that meant we lost track of
      interface files.  This fixes the problem that led Sven to add lots of
      import PprType() decls.  I've removed them all again!
      783e505e
  17. 24 Mar, 2000 1 commit
    • simonpj's avatar
      [project @ 2000-03-24 17:49:29 by simonpj] · 6c872fff
      simonpj authored
      a) Small wibbles to do with inlining and floating
      
      b) Implement Ralf's request, so that one can write
      
      	type F = forall a. a -> a
      
      	f :: Int -> F
      	f = ...
      
         The for-alls inside F are hoisted out to the top of
         the type signature for f.  This applies uniformly to
         all user-written types
      6c872fff
  18. 23 Mar, 2000 2 commits
    • simonpj's avatar
      [project @ 2000-03-23 17:45:17 by simonpj] · 111cee3f
      simonpj authored
      This utterly gigantic commit is what I've been up to in background
      mode in the last couple of months.  Originally the main goal
      was to get rid of Con (staturated constant applications)
      in the CoreExpr type, but one thing led to another, and I kept
      postponing actually committing.   Sorry.
      
      	Simon, 23 March 2000
      
      
      I've tested it pretty thoroughly, but doubtless things will break.
      
      Here are the highlights
      
      * Con is gone; the CoreExpr type is simpler
      * NoRepLits have gone
      * Better usage info in interface files => less recompilation
      * Result type signatures work
      * CCall primop is tidied up
      * Constant folding now done by Rules
      * Lots of hackery in the simplifier
      * Improvements in CPR and strictness analysis
      
      Many bug fixes including
      
      * Sergey's DoCon compiles OK; no loop in the strictness analyser
      * Volker Wysk's programs don't crash the CPR analyser
      
      I have not done much on measuring compilation times and binary sizes;
      they could have got worse.  I think performance has got significantly
      better, though, in most cases.
      
      
      Removing the Con form of Core expressions
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      The big thing is that
      
        For every constructor C there are now *two* Ids:
      
      	C is the constructor's *wrapper*. It evaluates and unboxes arguments
      	before calling $wC.  It has a perfectly ordinary top-level defn
      	in the module defining the data type.
      
      	$wC is the constructor's *worker*.  It is like a primop that simply
      	allocates and builds the constructor value.  Its arguments are the
      	actual representation arguments of the constructor.
      	Its type may be different to C, because:
      		- useless dict args are dropped
      		- strict args may be flattened
      
        For every primop P there is *one* Id, its (curried) Id
      
        Neither contructor worker Id nor the primop Id have a defminition anywhere.
        Instead they are saturated during the core-to-STG pass, and the code generator
        generates code for them directly. The STG language still has saturated
        primops and constructor applications.
      
      * The Const type disappears, along with Const.lhs.  The literal part
        of Const.lhs reappears as Literal.lhs.  Much tidying up in here,
        to bring all the range checking into this one module.
      
      * I got rid of NoRep literals entirely.  They just seem to be too much trouble.
      
      * Because Con's don't exist any more, the funny C { args } syntax
        disappears from inteface files.
      
      
      Parsing
      ~~~~~~~
      * Result type signatures now work
      	f :: Int -> Int = \x -> x
      	-- The Int->Int is the type of f
      
      	g x y :: Int = x+y
      	-- The Int is the type of the result of (g x y)
      
      
      Recompilation checking and make
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * The .hi file for a modules is not touched if it doesn't change.  (It used to
        be touched regardless, forcing a chain of recompilations.)  The penalty for this
        is that we record exported things just as if they were mentioned in the body of
        the module.  And the penalty for that is that we may recompile a module when
        the only things that have changed are the things it is passing on without using.
        But it seems like a good trade.
      
      * -recomp is on by default
      
      Foreign declarations
      ~~~~~~~~~~~~~~~~~~~~
      * If you say
      	foreign export zoo :: Int -> IO Int
        then you get a C produre called 'zoo', not 'zzoo' as before.
        I've also added a check that complains if you export (or import) a C
        procedure whose name isn't legal C.
      
      
      Code generation and labels
      ~~~~~~~~~~~~~~~~~~~~~~~~~~
      * Now that constructor workers and wrappers have distinct names, there's
        no need to have a Foo_static_closure and a Foo_closure for constructor Foo.
        I nuked the entire StaticClosure story.  This has effects in some of
        the RTS headers (i.e. s/static_closure/closure/g)
      
      
      Rules, constant folding
      ~~~~~~~~~~~~~~~~~~~~~~~
      * Constant folding becomes just another rewrite rule, attached to the Id for the
        PrimOp.   To achieve this, there's a new form of Rule, a BuiltinRule (see CoreSyn.lhs).
        The prelude rules are in prelude/PrelRules.lhs, while simplCore/ConFold.lhs has gone.
      
      * Appending of constant strings now works, using fold/build fusion, plus
        the rewrite rule
      	unpack "foo" c (unpack "baz" c n)  =  unpack "foobaz" c n
        Implemented in PrelRules.lhs
      
      * The CCall primop is tidied up quite a bit.  There is now a data type CCall,
        defined in PrimOp, that packages up the info needed for a particular CCall.
        There is a new Id for each new ccall, with an big "occurrence name"
      	{__ccall "foo" gc Int# -> Int#}
        In interface files, this is parsed as a single Id, which is what it is, really.
      
      Miscellaneous
      ~~~~~~~~~~~~~
      * There were numerous places where the host compiler's
        minInt/maxInt was being used as the target machine's minInt/maxInt.
        I nuked all of these; everything is localised to inIntRange and inWordRange,
        in Literal.lhs
      
      * Desugaring record updates was broken: it didn't generate correct matches when
        used withe records with fancy unboxing etc.  It now uses matchWrapper.
      
      * Significant tidying up in codeGen/SMRep.lhs
      
      * Add __word, __word64, __int64 terminals to signal the obvious types
        in interface files.  Add the ability to print word values in hex into
        C code.
      
      * PrimOp.lhs is no longer part of a loop.  Remove PrimOp.hi-boot*
      
      
      Types
      ~~~~~
      * isProductTyCon no longer returns False for recursive products, nor
        for unboxed products; you have to test for these separately.
        There's no reason not to do CPR for recursive product types, for example.
        Ditto splitProductType_maybe.
      
      Simplification
      ~~~~~~~~~~~~~~~
      * New -fno-case-of-case flag for the simplifier.  We use this in the first run
        of the simplifier, where it helps to stop messing up expressions that
        the (subsequent) full laziness pass would otherwise find float out.
        It's much more effective than previous half-baked hacks in inlining.
      
        Actually, it turned out that there were three places in Simplify.lhs that
        needed to know use this flag.
      
      * Make the float-in pass push duplicatable bindings into the branches of
        a case expression, in the hope that we never have to allocate them.
        (see FloatIn.sepBindsByDropPoint)
      
      * Arrange that top-level bottoming Ids get a NOINLINE pragma
        This reduced gratuitous inlining of error messages.
        But arrange that such things still get w/w'd.
      
      * Arrange that a strict argument position is regarded as an 'interesting'
        context, so that if we see
      	foldr k z (g x)
        then we'll be inclined to inline g; this can expose a build.
      
      * There was a missing case in CoreUtils.exprEtaExpandArity that meant
        we were missing some obvious cases for eta expansion
        Also improve the code when handling applications.
      
      * Make record selectors (identifiable by their IdFlavour) into "cheap" operations.
      	  [The change is a 2-liner in CoreUtils.exprIsCheap]
        This means that record selection may be inlined into function bodies, which
        greatly improves the arities of overloaded functions.
      
      * Make a cleaner job of inlining "lone variables".  There was some distributed
        cunning, but I've centralised it all now in SimplUtils.analyseCont, which
        analyses the context of a call to decide whether it is "interesting".
      
      * Don't specialise very small functions in Specialise.specDefn
        It's better to inline it.  Rather like the worker/wrapper case.
      
      * Be just a little more aggressive when floating out of let rhss.
        See comments with Simplify.wantToExpose
        A small change with an occasional big effect.
      
      * Make the inline-size computation think that
      	case x of I# x -> ...
        is *free*.
      
      
      CPR analysis
      ~~~~~~~~~~~~
      * Fix what was essentially a bug in CPR analysis.  Consider
      
      	letrec f x = let g y = let ... in f e1
      		     in
      		     if ... then (a,b) else g x
      
        g has the CPR property if f does; so when generating the final annotated
        RHS for f, we must use an envt in which f is bound to its final abstract
        value.  This wasn't happening.  Instead, f was given the CPR tag but g
        wasn't; but of course the w/w pass gives rotten results in that case!!
        (Because f's CPR-ness relied on g's.)
      
        On they way I tidied up the code in CprAnalyse.  It's quite a bit shorter.
      
        The fact that some data constructors return a constructed product shows
        up in their CPR info (MkId.mkDataConId) not in CprAnalyse.lhs
      
      
      
      Strictness analysis and worker/wrapper
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * BIG THING: pass in the demand to StrictAnal.saExpr.  This affects situations
        like
      	f (let x = e1 in (x,x))
        where f turns out to have strictness u(SS), say.  In this case we can
        mark x as demanded, and use a case expression for it.
      
        The situation before is that we didn't "know" that there is the u(SS)
        demand on the argument, so we simply computed that the body of the let
        expression is lazy in x, and marked x as lazily-demanded.  Then even after
        f was w/w'd we got
      
      	let x = e1 in case (x,x) of (a,b) -> $wf a b
      
        and hence
      
      	let x = e1 in $wf a b
      
        I found a much more complicated situation in spectral/sphere/Main.shade,
        which improved quite a bit with this change.
      
      * Moved the StrictnessInfo type from IdInfo to Demand.  It's the logical
        place for it, and helps avoid module loops
      
      * Do worker/wrapper for coerces even if the arity is zero.  Thus:
      	stdout = coerce Handle (..blurg..)
        ==>
      	wibble = (...blurg...)
      	stdout = coerce Handle wibble
        This is good because I found places where we were saying
      	case coerce t stdout of { MVar a ->
      	...
      	case coerce t stdout of { MVar b ->
      	...
        and the redundant case wasn't getting eliminated because of the coerce.
      111cee3f
    • sewardj's avatar
      [project @ 2000-03-23 12:22:04 by sewardj] · 1e5271f1
      sewardj authored
      In interface files, don't forget to mention the names of modules imported
      via hi-boot files.  This is needed so that Hugs can use the import decls
      in interface files to safely overestimate the dependency sets which it will
      encounter when linking object code.
      1e5271f1
  19. 02 Mar, 2000 1 commit
  20. 25 Feb, 2000 1 commit
    • panne's avatar
      [project @ 2000-02-25 14:55:31 by panne] · f83a5a68
      panne authored
      Deprecations of variables now works, although the source location is
      not yet reported correctly and the code needs some cleanup. Added a
      new flag -fwarn-deprecations to the set of standard warnings. The
      syntax of deprecations has been extended to deprecate types, classes,
      or even constructors, although this does not work yet.
      f83a5a68
  21. 22 Feb, 2000 1 commit
    • panne's avatar
      [project @ 2000-02-22 15:47:56 by panne] · b78eb7be
      panne authored
      Load deprecations from interface files into a deprecation environment
      which maps Names to RenamedDeprecations. This map is not used yet, but
      very soon it will...
      
      This commit fixes a bug related to implicit parameters, too:
      Previously, an interface file containing the name "with" could not be
      read by the interface parser. This broke Malcolm's HaXml 0.9 (released
      today). Remember Sven's glaexts-commandment (Jeffrey? :-) : Always
      keep Lex.lhs's ghcExtensionKeywordsFM and ParseIface.y's var_fs
      production in synch!
      b78eb7be
  22. 10 Feb, 2000 1 commit
  23. 20 Dec, 1999 1 commit
    • simonpj's avatar
      [project @ 1999-12-20 10:34:27 by simonpj] · e921b2e3
      simonpj authored
      This commit implements a substantial re-organisation of the Prelude
      It also fixes a couple of small renamer bugs that were reported recently
      	(notably, Sven pointed out that we weren't reporting
      	unused imports properly)
      
      My original goal was to get rid of all "orphan" modules (i.e. ones
      with instance decls that don't belong either to a tycon or a class
      defined in the same module).  This should reduce the number of
      interface files that have to be read when compiling small Haskell
      modules.
      
      But like most expeditions into the Prelude Swamp, it spiraled out
      of control.  The result is quite satisfactory, though.
      
      	GONE AWAY:	PrelCCall, PrelNumExtra
      
      	NEW:		PrelReal, PrelFloat, PrelByteArr, PrelNum.hi-boot
      
      (The extra PrelNum.hi-boot is because of a tiresome thin-air Id, addr2Integer,
      which used to be in PrelBase.)
      
      Quite a lot of types have moved from one module to another,
      which entails some changes to part of the compiler (PrelInfo, PrelMods) etc,
      and there are a few places in the RTS includes and even in the driver
      that know about these home modules (alas).
      
      So the rough structure is as follows, in (linearised) dependency order
      	[this list now appears in PrelBase.lhs]
      
      PrelGHC		Has no implementation.  It defines built-in things, and
      		by importing it you bring them into scope.
      		The source file is PrelGHC.hi-boot, which is just
      		copied to make PrelGHC.hi
      
      		Classes: CCallable, CReturnable
      
      PrelBase	Classes: Eq, Ord, Functor, Monad
      		Types:   list, (), Int, Bool, Ordering, Char, String
      
      PrelTup		Types: tuples, plus instances for PrelBase classes
      
      PrelShow	Class: Show, plus instances for PrelBase/PrelTup types
      
      PrelEnum	Class: Enum,  plus instances for PrelBase/PrelTup types
      
      PrelMaybe	Type: Maybe, plus instances for PrelBase classes
      
      PrelNum		Class: Num, plus instances for Int
      		Type:  Integer, plus instances for all classes so far (Eq, Ord, Num, Show)
      
      		Integer is needed here because it is mentioned in the signature
      		of 'fromInteger' in class Num
      
      PrelReal	Classes: Real, Integral, Fractional, RealFrac
      			 plus instances for Int, Integer
      		Types:  Ratio, Rational
      			plus intances for classes so far
      
      		Rational is needed here because it is mentioned in the signature
      		of 'toRational' in class Real
      
      Ix		Classes: Ix, plus instances for Int, Bool, Char, Integer, Ordering, tuples
      
      PrelArr		Types: Array, MutableArray, MutableVar
      
      		Does *not* contain any ByteArray stuff (see PrelByteArr)
      		Arrays are used by a function in PrelFloat
      
      PrelFloat	Classes: Floating, RealFloat
      		Types:   Float, Double, plus instances of all classes so far
      
      		This module contains everything to do with floating point.
      		It is a big module (900 lines)
      		With a bit of luck, many modules can be compiled without ever reading PrelFloat.hi
      
      PrelByteArr	Types: ByteArray, MutableByteArray
      
      		We want this one to be after PrelFloat, because it defines arrays
      		of unboxed floats.
      
      
      Other Prelude modules are much easier with fewer complex dependencies.
      e921b2e3
  24. 10 Dec, 1999 1 commit
  25. 09 Dec, 1999 1 commit
    • simonpj's avatar
      [project @ 1999-12-09 12:30:56 by simonpj] · 39262efa
      simonpj authored
      A bunch of small changes in the way that usage information
      is generated to stuff into interface files.  I'm not certain
      anything was really wrong before, but it's tidier now, and
      there are slightly fewer dependencies generated.  Main
      differences are in RnIfaces.getImportVersions
      
      I also made the check for orphan rules a bit cleverer
      (Rename.isOrphanDecl) so that we get fewer spurious orphan modules.
      
      Simon
      39262efa
  26. 02 Dec, 1999 1 commit
  27. 30 Nov, 1999 1 commit
    • lewie's avatar
      [project @ 1999-11-30 16:10:07 by lewie] · e1e1d020
      lewie authored
      First bits o' functional dependencies - just the syntax and related
      datatypes, plus started moving some of the static checks from the
      renamer (where we don't know about fundeps) to later in the typechecker.
      e1e1d020
  28. 29 Nov, 1999 1 commit
    • simonpj's avatar
      [project @ 1999-11-29 17:34:14 by simonpj] · e1a4f2a5
      simonpj authored
      Make it so that a class decl generates default method decls
      for every method, not just for the ones that the user supplies
      default-methods for.
      
      GHC will never call these default-default methods, because
      when it finds an instance decl with no defn for a method,
      *and* the class decl doesn't have a user-programmed default
      method, it whips up a new default method for that instance
      decl so that the error message is more informative than
      the default-default method would be.
      
      But Hugs isn't so smart, and wants to call something from
      the class decl.
      
      This change required fiddling with more than I expected.  Sigh.
      
      Simon
      e1a4f2a5
  29. 16 Sep, 1999 1 commit
  30. 24 Aug, 1999 1 commit
    • simonpj's avatar
      [project @ 1999-08-24 08:59:14 by simonpj] · 7d845299
      simonpj authored
      Record all orphan modules (including "library" ones)
      in the usage info in an interface file.  Leaving these out
      prevents propagation of orphan module information.
      7d845299
  31. 08 Jul, 1999 1 commit
  32. 06 Jul, 1999 1 commit
    • simonpj's avatar
      [project @ 1999-07-06 16:45:31 by simonpj] · 9d38678e
      simonpj authored
      All Simon's recent tuning changes.  Rough summary follows:
      
      * Fix Kevin Atkinson's cant-find-instance bug.  Turns out that Rename.slurpSourceRefs
        needs to repeatedly call getImportedInstDecls, and then go back to slurping
        source-refs.  Comments with Rename.slurpSourceRefs.
      
      * Add a case to Simplify.mkDupableAlt for the quite-common case where there's
        a very simple alternative, in which case there's no point in creating a
        join-point binding.
      
      * Fix CoreUtils.exprOkForSpeculation so that it returns True of (==# a# b#).
        This lack meant that
      	case ==# a# b# of { True -> x; False -> x }
        was not simplifying
      
      * Make float-out dump bindings at the top of a function argument, as
        at the top of a let(rec) rhs.  See notes with FloatOut.floatRhs
      
      * Make the ArgOf case of mkDupableAlt generate a OneShot lambda.
        This gave a noticeable boost to spectral/boyer2
      
      
      * Reduce the number of coerces, using worker/wrapper stuff.
        The main idea is in WwLib.mkWWcoerce.  The gloss is that we must do
        the w/w split even for small non-recursive things.  See notes with
        WorkWrap.tryWw.
      
      * This further complicated getWorkerId, so I finally bit the bullet and
        make the workerInfo field of the IdInfo work properly, including
        under substitutions.  Death to getWorkerId.  Kevin Glynn will be happy.
      
      * Make all lambdas over realWorldStatePrimTy
        into one-shot lambdas.  This is a GROSS HACK.
      
      * Also make the occurrence analyser aware of one-shot lambdas.
      
      * Make various Prelude things into INLINE, so that foldr doesn't
        get inlined in their body, so that the caller gets the benefit
        of fusion.  Notably in PrelArr.lhs.
      9d38678e
  33. 05 Jul, 1999 1 commit
    • simonpj's avatar
      [project @ 1999-07-05 15:30:25 by simonpj] · 8ae0e52a
      simonpj authored
      Make sure that instance gates have their home modules
      loaded by RnIfaces.getImportedInstDecls.  This was causing
      Kevin Atkinson's missing-instance bug.
      8ae0e52a
  34. 28 Jun, 1999 1 commit
  35. 17 Jun, 1999 1 commit
  36. 08 Jun, 1999 1 commit
  37. 01 Jun, 1999 1 commit
    • simonmar's avatar
      [project @ 1999-06-01 16:40:41 by simonmar] · 904f158f
      simonmar authored
      This commit replaces the old yacc parser with a Happy-generated one.
      Notes:
      
      	- The generated .hs file is *big*.  Best to use a recent
      	  version of Happy, and even better to add the -c flag
      	  to use unsafeCoerce# with ghc (versions 4.02+ please).
      
      	- The lexer has grown all sorts of unsightly growths and
      	  should be put down as soon as possible.
      
      	- Parse errors may result in strange diagnostics.  I'm looking
      	  into this.
      
      	- HsSyn now contains a few extra constructors due to the way
      	  patterns are parsed as expressions in the parser.
      
      	- The layout rule is implemented according to the Haskell
      	  report.  I found a couple of places in the libraries where
      	  we previously weren't adhering to this - in particular the
      	  rule about "nested contexts must be more indented than
      	  outer contexts".  The rule is necessary to disambiguate
      	  in the presence of empty declaration lists.
      904f158f
  38. 26 May, 1999 1 commit