X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FhsSyn%2FHsBinds.lhs;h=2544515391cf25349ed3aef27aad9683eb1dbcef;hp=a6d8523e93e752b13e0663017695a31d956b284c;hb=a3bab0506498db41853543558c52a4fda0d183af;hpb=72462499b891d5779c19f3bda03f96e24f9554ae diff --git a/compiler/hsSyn/HsBinds.lhs b/compiler/hsSyn/HsBinds.lhs index a6d8523..2544515 100644 --- a/compiler/hsSyn/HsBinds.lhs +++ b/compiler/hsSyn/HsBinds.lhs @@ -13,6 +13,7 @@ Datatype for: @BindGroup@, @Bind@, @Sig@, @Bind@. -- any warnings in the module. See -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings -- for details +{-# LANGUAGE DeriveDataTypeable #-} module HsBinds where @@ -31,9 +32,14 @@ import BasicTypes import Outputable import SrcLoc import Util +import VarEnv import Var import Bag +import Unique import FastString + +import Data.IORef( IORef ) +import Data.Data hiding ( Fixity ) \end{code} %************************************************************************ @@ -58,24 +64,25 @@ data HsLocalBindsLR idL idR -- Bindings in a 'let' expression = HsValBinds (HsValBindsLR idL idR) | HsIPBinds (HsIPBinds idR) | EmptyLocalBinds + deriving (Data, Typeable) type HsValBinds id = HsValBindsLR id id data HsValBindsLR idL idR -- Value bindings (not implicit parameters) - = ValBindsIn -- Before typechecking + = ValBindsIn -- Before renaming (LHsBindsLR idL idR) [LSig idR] -- Not dependency analysed -- Recursive by default - | ValBindsOut -- After renaming + | ValBindsOut -- After renaming [(RecFlag, LHsBinds idL)] -- Dependency analysed, later bindings -- in the list may depend on earlier -- ones. [LSig Name] + deriving (Data, Typeable) -type LHsBinds id = Bag (LHsBind id) -type DictBinds id = LHsBinds id -- Used for dictionary or method bindings -type LHsBind id = Located (HsBind id) -type HsBind id = HsBindLR id id +type LHsBinds id = Bag (LHsBind id) +type LHsBind id = Located (HsBind id) +type HsBind id = HsBindLR id id type LHsBindLR idL idR = Located (HsBindLR idL idR) type LHsBindsLR idL idR = Bag (LHsBindLR idL idR) @@ -118,7 +125,7 @@ data HsBindLR idL idR -- Before renaming, and after typechecking, -- the field is unused; it's just an error thunk - fun_tick :: Maybe (Int,[idR]) -- ^ This is the (optional) module-local tick number. + fun_tick :: Maybe (Int,[Id]) -- ^ This is the (optional) module-local tick number. } | PatBind { -- The pattern is never a simple variable; @@ -136,18 +143,20 @@ data HsBindLR idL idR -- (used for implication constraints only) } - | AbsBinds { -- Binds abstraction; TRANSLATION + | AbsBinds { -- Binds abstraction; TRANSLATION abs_tvs :: [TyVar], - abs_dicts :: [DictId], -- Includes equality constraints + abs_ev_vars :: [EvVar], -- Includes equality constraints -- AbsBinds only gets used when idL = idR after renaming, -- but these need to be idL's for the collect... code in HsUtil to have -- the right type - abs_exports :: [([TyVar], idL, idL, [LSpecPrag])], -- (tvs, poly_id, mono_id, prags) - abs_binds :: LHsBinds idL -- The dictionary bindings and typechecked user bindings - -- mixed up together; you can tell the dict bindings because - -- they are all VarBinds + abs_exports :: [([TyVar], idL, idL, TcSpecPrags)], -- (tvs, poly_id, mono_id, prags) + + abs_ev_binds :: TcEvBinds, -- Evidence bindings + abs_binds :: LHsBinds idL -- Typechecked user bindings } + + deriving (Data, Typeable) -- Consider (AbsBinds tvs ds [(ftvs, poly_f, mono_f) binds] -- -- Creates bindings for (polymorphic, overloaded) poly_f @@ -237,6 +246,13 @@ plusHsValBinds (ValBindsIn ds1 sigs1) (ValBindsIn ds2 sigs2) = ValBindsIn (ds1 `unionBags` ds2) (sigs1 ++ sigs2) plusHsValBinds (ValBindsOut ds1 sigs1) (ValBindsOut ds2 sigs2) = ValBindsOut (ds1 ++ ds2) (sigs1 ++ sigs2) + +getTypeSigNames :: HsValBinds a -> NameSet +-- Get the names that have a user type sig +getTypeSigNames (ValBindsIn {}) + = panic "getTypeSigNames" +getTypeSigNames (ValBindsOut _ sigs) + = mkNameSet [unLoc n | L _ (TypeSig n _) <- sigs] \end{code} What AbsBinds means @@ -269,18 +285,24 @@ instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsBindLR idL id ppr_monobind :: (OutputableBndr idL, OutputableBndr idR) => HsBindLR idL idR -> SDoc -ppr_monobind (PatBind { pat_lhs = pat, pat_rhs = grhss }) = pprPatBind pat grhss -ppr_monobind (VarBind { var_id = var, var_rhs = rhs }) = pprBndr CaseBind var <+> equals <+> pprExpr (unLoc rhs) +ppr_monobind (PatBind { pat_lhs = pat, pat_rhs = grhss }) + = pprPatBind pat grhss +ppr_monobind (VarBind { var_id = var, var_rhs = rhs }) + = sep [pprBndr CaseBind var, nest 2 $ equals <+> pprExpr (unLoc rhs)] ppr_monobind (FunBind { fun_id = fun, fun_infix = inf, + fun_co_fn = wrap, fun_matches = matches, fun_tick = tick }) = pprTicks empty (case tick of Nothing -> empty Just t -> text "-- tick id = " <> ppr t) + $$ ifPprDebug (pprBndr LetBind (unLoc fun)) $$ pprFunBind (unLoc fun) inf matches + $$ ifPprDebug (ppr wrap) -ppr_monobind (AbsBinds { abs_tvs = tyvars, abs_dicts = dictvars, - abs_exports = exports, abs_binds = val_binds }) +ppr_monobind (AbsBinds { abs_tvs = tyvars, abs_ev_vars = dictvars + , abs_exports = exports, abs_binds = val_binds + , abs_ev_binds = ev_binds }) = sep [ptext (sLit "AbsBinds"), brackets (interpp'SP tyvars), brackets (interpp'SP dictvars), @@ -289,10 +311,12 @@ ppr_monobind (AbsBinds { abs_tvs = tyvars, abs_dicts = dictvars, nest 2 ( vcat [pprBndr LetBind x | (_,x,_,_) <- exports] -- Print type signatures $$ pprLHsBinds val_binds ) + $$ + ifPprDebug (ppr ev_binds) where ppr_exp (tvs, gbl, lcl, prags) = vcat [ppr gbl <+> ptext (sLit "<=") <+> ppr tvs <+> ppr lcl, - nest 2 (vcat (map (pprPrag gbl) prags))] + nest 2 (pprTcSpecPrags prags)] \end{code} @@ -315,11 +339,12 @@ pprTicks pp_no_debug pp_when_debug data HsIPBinds id = IPBinds [LIPBind id] - (DictBinds id) -- Only in typechecker output; binds + TcEvBinds -- Only in typechecker output; binds -- uses of the implicit parameters + deriving (Data, Typeable) isEmptyIPBinds :: HsIPBinds id -> Bool -isEmptyIPBinds (IPBinds is ds) = null is && isEmptyBag ds +isEmptyIPBinds (IPBinds is ds) = null is && isEmptyTcEvBinds ds type LIPBind id = Located (IPBind id) @@ -328,10 +353,11 @@ data IPBind id = IPBind (IPName id) (LHsExpr id) + deriving (Data, Typeable) instance (OutputableBndr id) => Outputable (HsIPBinds id) where ppr (IPBinds bs ds) = pprDeeperList vcat (map ppr bs) - $$ pprLHsBinds ds + $$ ifPprDebug (ppr ds) instance (OutputableBndr id) => Outputable (IPBind id) where ppr (IPBind id rhs) = pprBndr LetBind id <+> equals <+> pprExpr (unLoc rhs) @@ -351,64 +377,148 @@ instance (OutputableBndr id) => Outputable (IPBind id) where data HsWrapper = WpHole -- The identity coercion - | WpCompose HsWrapper HsWrapper -- (\a1..an. []) `WpCompose` (\x1..xn. []) - -- = (\a1..an \x1..xn. []) + | WpCompose HsWrapper HsWrapper + -- (wrap1 `WpCompse` wrap2)[e] = wrap1[ wrap2[ e ]] + -- + -- Hence (\a. []) `WpCompose` (\b. []) = (\a b. []) + -- But ([] a) `WpCompose` ([] b) = ([] b a) | WpCast Coercion -- A cast: [] `cast` co -- Guaranteed not the identity coercion - | WpApp Var -- [] d the 'd' is a type-class dictionary or coercion variable - - | WpTyApp Type -- [] t the 't' is a type or corecion - -- ToDo: it'd be tidier if 't' was always a type (not coercion), - -- but that is inconvenient in Inst.instCallDicts + -- Evidence abstraction and application + -- (both dictionaries and coercions) + | WpEvLam EvVar -- \d. [] the 'd' is an evidence variable + | WpEvApp EvTerm -- [] d the 'd' is evidence for a constraint - | WpLam Var -- \d. [] the 'd' is a type-class dictionary or coercion variable + -- Type abstraction and application | WpTyLam TyVar -- \a. [] the 'a' is a type variable (not coercion var) + | WpTyApp Type -- [] t the 't' is a type (not coercion) - -- Non-empty bindings, so that the identity coercion - -- is always exactly WpHole - | WpLet (LHsBinds Id) -- let binds in [] - -- (would be nicer to be core bindings) -instance Outputable HsWrapper where - ppr co_fn = pprHsWrapper (ptext (sLit "<>")) co_fn + | WpLet TcEvBinds -- Non-empty (or possibly non-empty) evidence bindings, + -- so that the identity coercion is always exactly WpHole + deriving (Data, Typeable) -pprHsWrapper :: SDoc -> HsWrapper -> SDoc -pprHsWrapper it wrap = - let - help it WpHole = it - help it (WpCompose f1 f2) = help (help it f2) f1 - help it (WpCast co) = sep [it, nest 2 (ptext (sLit "`cast`") <+> pprParendType co)] - help it (WpApp id) = sep [it, nest 2 (ppr id)] - help it (WpTyApp ty) = sep [it, ptext (sLit "@") <+> pprParendType ty] - help it (WpLam id) = sep [ptext (sLit "\\") <> pprBndr LambdaBind id <> dot, it] - help it (WpTyLam tv) = sep [ptext (sLit "/\\") <> pprBndr LambdaBind tv <> dot, it] - help it (WpLet binds) = sep [ptext (sLit "let") <+> braces (ppr binds), it] - in - -- in debug mode, print the wrapper - -- otherwise just print what's inside - getPprStyle (\ s -> if debugStyle s then (help it wrap) else it) +data TcEvBinds + = TcEvBinds -- Mutable evidence bindings + EvBindsVar -- Mutable because they are updated "later" + -- when an implication constraint is solved + + | EvBinds -- Immutable after zonking + (Bag EvBind) + + deriving( Typeable ) + +data EvBindsVar = EvBindsVar (IORef EvBindMap) Unique + -- The Unique is only for debug printing + +----------------- +type EvBindMap = VarEnv EvBind + +emptyEvBindMap :: EvBindMap +emptyEvBindMap = emptyVarEnv + +extendEvBinds :: EvBindMap -> EvVar -> EvTerm -> EvBindMap +extendEvBinds bs v t = extendVarEnv bs v (EvBind v t) + +lookupEvBind :: EvBindMap -> EvVar -> Maybe EvBind +lookupEvBind = lookupVarEnv + +evBindMapBinds :: EvBindMap -> Bag EvBind +evBindMapBinds = foldVarEnv consBag emptyBag + +----------------- +instance Data TcEvBinds where + -- Placeholder; we can't travers into TcEvBinds + toConstr _ = abstractConstr "TcEvBinds" + gunfold _ _ = error "gunfold" + dataTypeOf _ = mkNoRepType "TcEvBinds" + +-- All evidence is bound by EvBinds; no side effects +data EvBind = EvBind EvVar EvTerm + +data EvTerm + = EvId EvId -- Term-level variable-to-variable bindings + -- (no coercion variables! they come via EvCoercion) + + | EvCoercion Coercion -- Coercion bindings + + | EvCast EvVar Coercion -- d |> co + + | EvDFunApp DFunId -- Dictionary instance application + [Type] [EvVar] + + | EvSuperClass DictId Int -- n'th superclass. Used for both equalities and + -- dictionaries, even though the former have no + -- selector Id. We count up from _0_ + + deriving( Data, Typeable) + +evVarTerm :: EvVar -> EvTerm +evVarTerm v | isCoVar v = EvCoercion (mkCoVarCoercion v) + | otherwise = EvId v +\end{code} + +Note [EvBinds/EvTerm] +~~~~~~~~~~~~~~~~~~~~~ +How evidence is created and updated. Bindings for dictionaries, +and coercions and implicit parameters are carried around in TcEvBinds +which during constraint generation and simplification is always of the +form (TcEvBinds ref). After constraint simplification is finished it +will be transformed to t an (EvBinds ev_bag). + +Evidence for coercions *SHOULD* be filled in using the TcEvBinds +However, all EvVars that correspond to *wanted* coercion terms in +an EvBind must be mutable variables so that they can be readily +inlined (by zonking) after constraint simplification is finished. + +Conclusion: a new wanted coercion variable should be made mutable. +[Notice though that evidence variables that bind coercion terms + from super classes will be "given" and hence rigid] + + +\begin{code} +emptyTcEvBinds :: TcEvBinds +emptyTcEvBinds = EvBinds emptyBag + +isEmptyTcEvBinds :: TcEvBinds -> Bool +isEmptyTcEvBinds (EvBinds b) = isEmptyBag b +isEmptyTcEvBinds (TcEvBinds {}) = panic "isEmptyTcEvBinds" + (<.>) :: HsWrapper -> HsWrapper -> HsWrapper WpHole <.> c = c c <.> WpHole = c c1 <.> c2 = c1 `WpCompose` c2 mkWpTyApps :: [Type] -> HsWrapper -mkWpTyApps tys = mk_co_fn WpTyApp (reverse tys) +mkWpTyApps tys = mk_co_app_fn WpTyApp tys -mkWpApps :: [Var] -> HsWrapper -mkWpApps ids = mk_co_fn WpApp (reverse ids) +mkWpEvApps :: [EvTerm] -> HsWrapper +mkWpEvApps args = mk_co_app_fn WpEvApp args + +mkWpEvVarApps :: [EvVar] -> HsWrapper +mkWpEvVarApps vs = mkWpEvApps (map evVarTerm vs) mkWpTyLams :: [TyVar] -> HsWrapper -mkWpTyLams ids = mk_co_fn WpTyLam ids +mkWpTyLams ids = mk_co_lam_fn WpTyLam ids mkWpLams :: [Var] -> HsWrapper -mkWpLams ids = mk_co_fn WpLam ids +mkWpLams ids = mk_co_lam_fn WpEvLam ids + +mkWpLet :: TcEvBinds -> HsWrapper +-- This no-op is a quite a common case +mkWpLet (EvBinds b) | isEmptyBag b = WpHole +mkWpLet ev_binds = WpLet ev_binds + +mk_co_lam_fn :: (a -> HsWrapper) -> [a] -> HsWrapper +mk_co_lam_fn f as = foldr (\x wrap -> f x `WpCompose` wrap) WpHole as -mk_co_fn :: (a -> HsWrapper) -> [a] -> HsWrapper -mk_co_fn f as = foldr (WpCompose . f) WpHole as +mk_co_app_fn :: (a -> HsWrapper) -> [a] -> HsWrapper +-- For applications, the *first* argument must +-- come *last* in the composition sequence +mk_co_app_fn f as = foldr (\x wrap -> wrap `WpCompose` f x) WpHole as idHsWrapper :: HsWrapper idHsWrapper = WpHole @@ -418,6 +528,55 @@ isIdHsWrapper WpHole = True isIdHsWrapper _ = False \end{code} +Pretty printing + +\begin{code} +instance Outputable HsWrapper where + ppr co_fn = pprHsWrapper (ptext (sLit "<>")) co_fn + +pprHsWrapper :: SDoc -> HsWrapper -> SDoc +-- In debug mode, print the wrapper +-- otherwise just print what's inside +pprHsWrapper doc wrap + = getPprStyle (\ s -> if debugStyle s then (help (add_parens doc) wrap False) else doc) + where + help :: (Bool -> SDoc) -> HsWrapper -> Bool -> SDoc + -- True <=> appears in function application position + -- False <=> appears as body of let or lambda + help it WpHole = it + help it (WpCompose f1 f2) = help (help it f2) f1 + help it (WpCast co) = add_parens $ sep [it False, nest 2 (ptext (sLit "|>") + <+> pprParendType co)] + help it (WpEvApp id) = no_parens $ sep [it True, nest 2 (ppr id)] + help it (WpTyApp ty) = no_parens $ sep [it True, ptext (sLit "@") <+> pprParendType ty] + help it (WpEvLam id) = add_parens $ sep [ ptext (sLit "\\") <> pp_bndr id, it False] + help it (WpTyLam tv) = add_parens $ sep [ptext (sLit "/\\") <> pp_bndr tv, it False] + help it (WpLet binds) = add_parens $ sep [ptext (sLit "let") <+> braces (ppr binds), it False] + + pp_bndr v = pprBndr LambdaBind v <> dot + + add_parens, no_parens :: SDoc -> Bool -> SDoc + add_parens d True = parens d + add_parens d False = d + no_parens d _ = d + +instance Outputable TcEvBinds where + ppr (TcEvBinds v) = ppr v + ppr (EvBinds bs) = ptext (sLit "EvBinds") <> braces (ppr bs) + +instance Outputable EvBindsVar where + ppr (EvBindsVar _ u) = ptext (sLit "EvBindsVar") <> angleBrackets (ppr u) + +instance Outputable EvBind where + ppr (EvBind v e) = ppr v <+> equals <+> ppr e + +instance Outputable EvTerm where + ppr (EvId v) = ppr v + ppr (EvCast v co) = ppr v <+> (ptext (sLit "`cast`")) <+> pprParendType co + ppr (EvCoercion co) = ppr co + ppr (EvSuperClass d n) = ptext (sLit "sc") <> parens (ppr (d,n)) + ppr (EvDFunApp df tys ts) = ppr df <+> sep [ char '@' <> ppr tys, ppr ts ] +\end{code} %************************************************************************ %* * @@ -466,17 +625,40 @@ data Sig name -- Signatures and pragmas -- {-# SPECIALISE instance Eq [Int] #-} | SpecInstSig (LHsType name) -- (Class tys); should be a specialisation of the -- current instance decl + deriving (Data, Typeable) type LFixitySig name = Located (FixitySig name) data FixitySig name = FixitySig (Located name) Fixity + deriving (Data, Typeable) + +-- TsSpecPrags conveys pragmas from the type checker to the desugarer +data TcSpecPrags + = IsDefaultMethod -- Super-specialised: a default method should + -- be macro-expanded at every call site + | SpecPrags [LTcSpecPrag] + deriving (Data, Typeable) --- A Prag conveys pragmas from the type checker to the desugarer -type LSpecPrag = Located SpecPrag -data SpecPrag +type LTcSpecPrag = Located TcSpecPrag + +data TcSpecPrag = SpecPrag + Id -- The Id to be specialised HsWrapper -- An wrapper, that specialises the polymorphic function InlinePragma -- Inlining spec for the specialised function + deriving (Data, Typeable) + +noSpecPrags :: TcSpecPrags +noSpecPrags = SpecPrags [] + +hasSpecPrags :: TcSpecPrags -> Bool +hasSpecPrags (SpecPrags ps) = not (null ps) +hasSpecPrags IsDefaultMethod = False + +isDefaultMethod :: TcSpecPrags -> Bool +isDefaultMethod IsDefaultMethod = True +isDefaultMethod (SpecPrags {}) = False + \end{code} \begin{code} @@ -597,7 +779,11 @@ pprSpec var pp_ty inl = ptext (sLit "SPECIALIZE") <+> pp_inl <+> pprVarSig var p pp_inl | isDefaultInlinePragma inl = empty | otherwise = ppr inl -pprPrag :: Outputable id => id -> LSpecPrag -> SDoc -pprPrag var (L _ (SpecPrag _expr inl)) = pprSpec var (ptext (sLit "")) inl +pprTcSpecPrags :: TcSpecPrags -> SDoc +pprTcSpecPrags IsDefaultMethod = ptext (sLit "") +pprTcSpecPrags (SpecPrags ps) = vcat (map (ppr . unLoc) ps) + +instance Outputable TcSpecPrag where + ppr (SpecPrag var _ inl) = pprSpec var (ptext (sLit "")) inl \end{code}