X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FbasicTypes%2FDataCon.lhs;h=9ce966ee7743dbbfff37e6288f352bd5f5d10374;hb=fe3321f99f4d9c9ff40429a7ac290f8ef7ca3297;hp=8d300d288ca5146e45d53ff9d69ca76fd18b3699;hpb=8ddec564494dc7889ea7aa8b4133f08cf3e64e0c;p=ghc-hetmet.git diff --git a/compiler/basicTypes/DataCon.lhs b/compiler/basicTypes/DataCon.lhs index 8d300d2..9ce966e 100644 --- a/compiler/basicTypes/DataCon.lhs +++ b/compiler/basicTypes/DataCon.lhs @@ -1,4 +1,5 @@ % +% (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1998 % \section[DataCon]{@DataCon@: Data Constructors} @@ -9,10 +10,10 @@ module DataCon ( ConTag, fIRST_TAG, mkDataCon, dataConRepType, dataConSig, dataConFullSig, - dataConName, dataConTag, dataConTyCon, dataConUserType, - dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, dataConResTys, - dataConEqSpec, dataConTheta, dataConStupidTheta, - dataConInstArgTys, dataConOrigArgTys, + dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType, + dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, + dataConEqSpec, eqSpecPreds, dataConTheta, dataConStupidTheta, + dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy, dataConInstOrigArgTys, dataConRepArgTys, dataConFieldLabels, dataConFieldType, dataConStrictMarks, dataConExStricts, @@ -23,31 +24,30 @@ module DataCon ( isNullarySrcDataCon, isNullaryRepDataCon, isTupleCon, isUnboxedTupleCon, isVanillaDataCon, classDataCon, - splitProductType_maybe, splitProductType, + splitProductType_maybe, splitProductType, deepSplitProductType, + deepSplitProductType_maybe ) where #include "HsVersions.h" -import Type ( Type, ThetaType, - substTyWith, substTyVar, mkTopTvSubst, - mkForAllTys, mkFunTys, mkTyConApp, mkTyVarTy, mkTyVarTys, - splitTyConApp_maybe, - mkPredTys, isStrictPred, pprType - ) -import Coercion ( isEqPred, mkEqPred ) -import TyCon ( TyCon, FieldLabel, tyConDataCons, - isProductTyCon, isTupleTyCon, isUnboxedTupleTyCon, - isNewTyCon ) -import Class ( Class, classTyCon ) -import Name ( Name, NamedThing(..), nameUnique ) -import Var ( TyVar, Id ) -import BasicTypes ( Arity, StrictnessMark(..) ) +import Type +import Coercion +import TyCon +import Class +import Name +import Var +import BasicTypes import Outputable -import Unique ( Unique, Uniquable(..) ) -import ListSetOps ( assoc, minusList ) -import Util ( zipEqual, zipWithEqual ) -import List ( partition ) -import Maybes ( expectJust ) +import Unique +import ListSetOps +import Util +import Maybes +import FastString +import PackageConfig +import Module + +import Data.Char +import Data.Word \end{code} @@ -101,22 +101,55 @@ data constructor. The type checker translates it into either the wrapper Id The data con has one or two Ids associated with it: - The "worker Id", is the actual data constructor. - Its type may be different to the Haskell source constructor - because: - - useless dict args are dropped - - strict args may be flattened - The worker is very like a primop, in that it has no binding. +The "worker Id", is the actual data constructor. +* Every data constructor (newtype or data type) has a worker - Newtypes have no worker Id +* The worker is very like a primop, in that it has no binding. +* For a *data* type, the worker *is* the data constructor; + it has no unfolding - The "wrapper Id", $WC, whose type is exactly what it looks like - in the source program. It is an ordinary function, - and it gets a top-level binding like any other function. +* For a *newtype*, the worker has a compulsory unfolding which + does a cast, e.g. + newtype T = MkT Int + The worker for MkT has unfolding + \(x:Int). x `cast` sym CoT + Here CoT is the type constructor, witnessing the FC axiom + axiom CoT : T = Int - The wrapper Id isn't generated for a data type if the worker - and wrapper are identical. It's always generated for a newtype. +The "wrapper Id", $WC, goes as follows + +* Its type is exactly what it looks like in the source program. + +* It is an ordinary function, and it gets a top-level binding + like any other function. + +* The wrapper Id isn't generated for a data type if there is + nothing for the wrapper to do. That is, if its defn would be + $wC = C + +Why might the wrapper have anything to do? Two reasons: + +* Unboxing strict fields (with -funbox-strict-fields) + data T = MkT !(Int,Int) + $wMkT :: (Int,Int) -> T + $wMkT (x,y) = MkT x y + Notice that the worker has two fields where the wapper has + just one. That is, the worker has type + MkT :: Int -> Int -> T + +* Equality constraints for GADTs + data T a where { MkT :: a -> T [a] } + + The worker gets a type with explicit equality + constraints, thus: + MkT :: forall a b. (a=[b]) => b -> T a + + The wrapper has the programmer-specified type: + $wMkT :: a -> T [a] + $wMkT a x = MkT [a] a [a] x + The third argument is a coerion + [a] :: [a]:=:[a] @@ -205,7 +238,7 @@ data DataCon -- dcEqSpec = [a:=:(x,y)] -- dcTheta = [Ord x] -- dcOrigArgTys = [a,List b] - -- dcTyCon = T + -- dcRepTyCon = T dcVanilla :: Bool, -- True <=> This is a vanilla Haskell 98 data constructor -- Its type is of form @@ -218,6 +251,8 @@ data DataCon -- The declaration format is held in the TyCon (algTcGadtSyntax) dcUnivTyVars :: [TyVar], -- Universally-quantified type vars + -- INVARIANT: length matches arity of the dcRepTyCon + dcExTyVars :: [TyVar], -- Existentially-quantified type vars -- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS -- FOR THE PARENT TyCon. With GADTs the data con might not even have @@ -225,6 +260,9 @@ data DataCon -- [This is a change (Oct05): previously, vanilla datacons guaranteed to -- have the same type variables as their parent TyCon, but that seems ugly.] + -- INVARIANT: the UnivTyVars and ExTyVars all have distinct OccNames + -- Reason: less confusing, and easier to generate IfaceSyn + dcEqSpec :: [(TyVar,Type)], -- Equalities derived from the result type, -- *as written by the programmer* -- This field allows us to move conveniently between the two ways @@ -257,9 +295,11 @@ data DataCon dcOrigArgTys :: [Type], -- Original argument types -- (before unboxing and flattening of strict fields) - - -- Result type of constructor is T t1..tn - dcTyCon :: TyCon, -- Result tycon, T + dcOrigResTy :: Type, -- Original result type + -- NB: for a data instance, the original user result type may + -- differ from the DataCon's representation TyCon. Example + -- data instance T [a] where MkT :: a -> T [a] + -- The OrigResTy is T [a], but the dcRepTyCon might be :T123 -- Now the strictness annotations and field labels of the constructor dcStrictMarks :: [StrictnessMark], @@ -269,7 +309,7 @@ data DataCon dcFields :: [FieldLabel], -- Field labels for this constructor, in the - -- same order as the argument types; + -- same order as the dcOrigArgTys; -- length = 0 (if not a record) or dataConSourceArity. -- Constructor representation @@ -278,6 +318,10 @@ data DataCon -- and *including* existential dictionaries dcRepStrictness :: [StrictnessMark], -- One for each *representation* argument + -- See also Note [Data-con worker strictness] in MkId.lhs + + -- Result type of constructor is T t1..tn + dcRepTyCon :: TyCon, -- Result tycon, T dcRepType :: Type, -- Type of the constructor -- forall a x y. (a:=:(x,y), Ord x) => x -> y -> MkT a @@ -305,10 +349,9 @@ data DataCon } data DataConIds - = NewDC Id -- Newtypes have only a wrapper, but no worker - | AlgDC (Maybe Id) Id -- Algebraic data types always have a worker, and + = DCIds (Maybe Id) Id -- Algebraic data types always have a worker, and -- may or may not have a wrapper, depending on whether - -- the wrapper does anything. + -- the wrapper does anything. Newtypes just have a worker -- _Neither_ the worker _nor_ the wrapper take the dcStupidTheta dicts as arguments @@ -316,10 +359,10 @@ data DataConIds -- The worker takes dcRepArgTys as its arguments -- If the worker is absent, dcRepArgTys is the same as dcOrigArgTys - -- The 'Nothing' case of AlgDC is important + -- The 'Nothing' case of DCIds is important -- Not only is this efficient, -- but it also ensures that the wrapper is replaced - -- by the worker (becuase it *is* the wroker) + -- by the worker (becuase it *is* the worker) -- even when there are no args. E.g. in -- f (:) x -- the (:) *is* the worker. @@ -409,22 +452,30 @@ mkDataCon name declared_infix eq_spec theta orig_arg_tys tycon stupid_theta ids +-- Warning: mkDataCon is not a good place to check invariants. +-- If the programmer writes the wrong result type in the decl, thus: +-- data T a where { MkT :: S } +-- then it's possible that the univ_tvs may hit an assertion failure +-- if you pull on univ_tvs. This case is checked by checkValidDataCon, +-- so the error is detected properly... it's just that asaertions here +-- are a little dodgy. + = ASSERT( not (any isEqPred theta) ) -- We don't currently allow any equality predicates on -- a data constructor (apart from the GADT ones in eq_spec) con where is_vanilla = null ex_tvs && null eq_spec && null theta - con = ASSERT( is_vanilla || not (isNewTyCon tycon) ) - -- Invariant: newtypes have a vanilla data-con - MkData {dcName = name, dcUnique = nameUnique name, + con = MkData {dcName = name, dcUnique = nameUnique name, dcVanilla = is_vanilla, dcInfix = declared_infix, dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, dcStupidTheta = stupid_theta, dcTheta = theta, - dcOrigArgTys = orig_arg_tys, dcTyCon = tycon, + dcOrigArgTys = orig_arg_tys, dcOrigResTy = orig_res_ty, + dcRepTyCon = tycon, dcRepArgTys = rep_arg_tys, - dcStrictMarks = arg_stricts, dcRepStrictness = rep_arg_stricts, + dcStrictMarks = arg_stricts, + dcRepStrictness = rep_arg_stricts, dcFields = fields, dcTag = tag, dcRepType = ty, dcIds = ids } @@ -439,6 +490,15 @@ mkDataCon name declared_infix real_arg_tys = dict_tys ++ orig_arg_tys real_stricts = map mk_dict_strict_mark theta ++ arg_stricts + -- Example + -- data instance T (b,c) where + -- TI :: forall e. e -> T (e,e) + -- + -- The representation tycon looks like this: + -- data :R7T b c where + -- TI :: forall b1 c1. (b1 ~ c1) => b1 -> :R7T b1 c1 + orig_res_ty = mkFamilyTyConApp tycon (substTyVars (mkTopTvSubst eq_spec) univ_tvs) + -- Representation arguments and demands -- To do: eliminate duplication with MkId (rep_arg_stricts, rep_arg_tys) = computeRep real_stricts real_arg_tys @@ -467,7 +527,7 @@ dataConTag :: DataCon -> ConTag dataConTag = dcTag dataConTyCon :: DataCon -> TyCon -dataConTyCon = dcTyCon +dataConTyCon = dcRepTyCon dataConRepType :: DataCon -> Type dataConRepType = dcRepType @@ -493,28 +553,24 @@ dataConTheta = dcTheta dataConWorkId :: DataCon -> Id dataConWorkId dc = case dcIds dc of - AlgDC _ wrk_id -> wrk_id - NewDC _ -> pprPanic "dataConWorkId" (ppr dc) + DCIds _ wrk_id -> wrk_id dataConWrapId_maybe :: DataCon -> Maybe Id -- Returns Nothing if there is no wrapper for an algebraic data con -- and also for a newtype (whose constructor is inlined compulsorily) dataConWrapId_maybe dc = case dcIds dc of - AlgDC mb_wrap _ -> mb_wrap - NewDC wrap -> Nothing + DCIds mb_wrap _ -> mb_wrap dataConWrapId :: DataCon -> Id -- Returns an Id which looks like the Haskell-source constructor dataConWrapId dc = case dcIds dc of - AlgDC (Just wrap) _ -> wrap - AlgDC Nothing wrk -> wrk -- worker=wrapper - NewDC wrap -> wrap + DCIds (Just wrap) _ -> wrap + DCIds Nothing wrk -> wrk -- worker=wrapper dataConImplicitIds :: DataCon -> [Id] dataConImplicitIds dc = case dcIds dc of - AlgDC (Just wrap) work -> [wrap,work] - AlgDC Nothing work -> [work] - NewDC wrap -> [wrap] + DCIds (Just wrap) work -> [wrap,work] + DCIds Nothing work -> [work] dataConFieldLabels :: DataCon -> [FieldLabel] dataConFieldLabels = dcFields @@ -550,66 +606,71 @@ dataConRepStrictness :: DataCon -> [StrictnessMark] -- Core constructor application (Con dc args) dataConRepStrictness dc = dcRepStrictness dc -dataConSig :: DataCon -> ([TyVar], ThetaType, [Type]) +dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type) dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcTheta = theta, dcOrigArgTys = arg_tys, dcTyCon = tycon}) - = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ theta, arg_tys) + dcTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) + = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ theta, arg_tys, res_ty) dataConFullSig :: DataCon - -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, [Type]) + -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, [Type], Type) dataConFullSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcTheta = theta, dcOrigArgTys = arg_tys, dcTyCon = tycon}) - = (univ_tvs, ex_tvs, eq_spec, theta, arg_tys) + dcTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) + = (univ_tvs, ex_tvs, eq_spec, theta, arg_tys, res_ty) + +dataConOrigResTy :: DataCon -> Type +dataConOrigResTy dc = dcOrigResTy dc dataConStupidTheta :: DataCon -> ThetaType dataConStupidTheta dc = dcStupidTheta dc -dataConResTys :: DataCon -> [Type] -dataConResTys dc = [substTyVar env tv | tv <- dcUnivTyVars dc] - where - env = mkTopTvSubst (dcEqSpec dc) - dataConUserType :: DataCon -> Type -- The user-declared type of the data constructor -- in the nice-to-read form --- T :: forall a. a -> T [a] +-- T :: forall a b. a -> b -> T [a] -- rather than --- T :: forall b. forall a. (a=[b]) => a -> T b +-- T :: forall a c. forall b. (c=[a]) => a -> b -> T c +-- NB: If the constructor is part of a data instance, the result type +-- mentions the family tycon, not the internal one. dataConUserType (MkData { dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, dcTheta = theta, dcOrigArgTys = arg_tys, - dcTyCon = tycon }) + dcOrigResTy = res_ty }) = mkForAllTys ((univ_tvs `minusList` map fst eq_spec) ++ ex_tvs) $ mkFunTys (mkPredTys theta) $ mkFunTys arg_tys $ - mkTyConApp tycon (map (substTyVar subst) univ_tvs) - where - subst = mkTopTvSubst eq_spec + res_ty -dataConInstArgTys :: DataCon +dataConInstArgTys :: DataCon -- A datacon with no existentials or equality constraints + -- However, it can have a dcTheta (notably it can be a + -- class dictionary, with superclasses) -> [Type] -- Instantiated at these types - -- NB: these INCLUDE the existentially quantified arg types -> [Type] -- Needs arguments of these types - -- NB: these INCLUDE the existentially quantified dict args + -- NB: these INCLUDE any dict args -- but EXCLUDE the data-decl context which is discarded -- It's all post-flattening etc; this is a representation type -dataConInstArgTys (MkData {dcRepArgTys = arg_tys, - dcUnivTyVars = univ_tvs, - dcExTyVars = ex_tvs}) inst_tys - = ASSERT( length tyvars == length inst_tys ) - map (substTyWith tyvars inst_tys) arg_tys - where - tyvars = univ_tvs ++ ex_tvs - --- And the same deal for the original arg tys -dataConInstOrigArgTys :: DataCon -> [Type] -> [Type] -dataConInstOrigArgTys (MkData {dcOrigArgTys = arg_tys, - dcUnivTyVars = univ_tvs, - dcExTyVars = ex_tvs}) inst_tys - = ASSERT( length tyvars == length inst_tys ) - map (substTyWith tyvars inst_tys) arg_tys - where - tyvars = univ_tvs ++ ex_tvs +dataConInstArgTys dc@(MkData {dcRepArgTys = rep_arg_tys, + dcUnivTyVars = univ_tvs, dcEqSpec = eq_spec, + dcExTyVars = ex_tvs}) inst_tys + = ASSERT2 ( length univ_tvs == length inst_tys + , ptext SLIT("dataConInstArgTys") <+> ppr dc $$ ppr univ_tvs $$ ppr inst_tys) + ASSERT2 ( null ex_tvs && null eq_spec, ppr dc ) + map (substTyWith univ_tvs inst_tys) rep_arg_tys + +dataConInstOrigArgTys + :: DataCon -- Works for any DataCon + -> [Type] -- Includes existential tyvar args, but NOT + -- equality constraints or dicts + -> [Type] -- Returns just the instsantiated *value* arguments +-- For vanilla datacons, it's all quite straightforward +-- But for the call in MatchCon, we really do want just the value args +dataConInstOrigArgTys dc@(MkData {dcOrigArgTys = arg_tys, + dcUnivTyVars = univ_tvs, + dcExTyVars = ex_tvs}) inst_tys + = ASSERT2( length tyvars == length inst_tys + , ptext SLIT("dataConInstOrigArgTys") <+> ppr dc $$ ppr tyvars $$ ppr inst_tys ) + map (substTyWith tyvars inst_tys) arg_tys + where + tyvars = univ_tvs ++ ex_tvs \end{code} These two functions get the real argument types of the constructor, @@ -628,13 +689,26 @@ dataConRepArgTys :: DataCon -> [Type] dataConRepArgTys dc = dcRepArgTys dc \end{code} +The string :. identifying a constructor, which is attached +to its info table and used by the GHCi debugger and the heap profiler. We want +this string to be UTF-8, so we get the bytes directly from the FastStrings. + +\begin{code} +dataConIdentity :: DataCon -> [Word8] +dataConIdentity dc = bytesFS (packageIdFS (modulePackageId mod)) ++ + fromIntegral (ord ':') : bytesFS (moduleNameFS (moduleName mod)) ++ + fromIntegral (ord '.') : bytesFS (occNameFS (nameOccName name)) + where name = dataConName dc + mod = nameModule name +\end{code} + \begin{code} isTupleCon :: DataCon -> Bool -isTupleCon (MkData {dcTyCon = tc}) = isTupleTyCon tc +isTupleCon (MkData {dcRepTyCon = tc}) = isTupleTyCon tc isUnboxedTupleCon :: DataCon -> Bool -isUnboxedTupleCon (MkData {dcTyCon = tc}) = isUnboxedTupleTyCon tc +isUnboxedTupleCon (MkData {dcRepTyCon = tc}) = isUnboxedTupleTyCon tc isVanillaDataCon :: DataCon -> Bool isVanillaDataCon dc = dcVanilla dc @@ -645,6 +719,7 @@ isVanillaDataCon dc = dcVanilla dc classDataCon :: Class -> DataCon classDataCon clas = case tyConDataCons (classTyCon clas) of (dict_constr:no_more) -> ASSERT( null no_more ) dict_constr + [] -> panic "classDataCon" \end{code} %************************************************************************ @@ -678,7 +753,8 @@ splitProductType_maybe ty -- and for constructors visible -> Just (tycon, ty_args, data_con, dataConInstArgTys data_con ty_args) where - data_con = head (tyConDataCons tycon) + data_con = ASSERT( not (null (tyConDataCons tycon)) ) + head (tyConDataCons tycon) other -> Nothing splitProductType str ty @@ -687,6 +763,22 @@ splitProductType str ty Nothing -> pprPanic (str ++ ": not a product") (pprType ty) +deepSplitProductType_maybe ty + = do { (res@(tycon, tycon_args, _, _)) <- splitProductType_maybe ty + ; let {result + | isClosedNewTyCon tycon && not (isRecursiveTyCon tycon) + = deepSplitProductType_maybe (newTyConInstRhs tycon tycon_args) + | isNewTyCon tycon = Nothing -- cannot unbox through recursive + -- newtypes nor through families + | otherwise = Just res} + ; result + } + +deepSplitProductType str ty + = case deepSplitProductType_maybe ty of + Just stuff -> stuff + Nothing -> pprPanic (str ++ ": not a product") (pprType ty) + computeRep :: [StrictnessMark] -- Original arg strictness -> [Type] -- and types -> ([StrictnessMark], -- Representation arg strictness @@ -698,6 +790,7 @@ computeRep stricts tys unbox NotMarkedStrict ty = [(NotMarkedStrict, ty)] unbox MarkedStrict ty = [(MarkedStrict, ty)] unbox MarkedUnboxed ty = zipEqual "computeRep" (dataConRepStrictness arg_dc) arg_tys - where - (_, _, arg_dc, arg_tys) = splitProductType "unbox_strict_arg_ty" ty + where + (_tycon, _tycon_args, arg_dc, arg_tys) + = deepSplitProductType "unbox_strict_arg_ty" ty \end{code}