X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FId.lhs;h=2f5e93c428758c16d23595663116a80395419134;hp=eff4c153cb4519ee196aae37a2d9dda3301bee26;hb=4bc25e8c30559b7a6a87b39afcc79340ae778788;hpb=17b297d97d327620ed6bfab942f8992b2446f1bf diff --git a/compiler/basicTypes/Id.lhs b/compiler/basicTypes/Id.lhs index eff4c15..2f5e93c 100644 --- a/compiler/basicTypes/Id.lhs +++ b/compiler/basicTypes/Id.lhs @@ -5,33 +5,47 @@ \section[Id]{@Ids@: Value and constructor identifiers} \begin{code} -{-# OPTIONS_GHC -w #-} --- The above warning supression flag is a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings --- for details - +-- | +-- #name_types# +-- GHC uses several kinds of name internally: +-- +-- * 'OccName.OccName': see "OccName#name_types" +-- +-- * 'RdrName.RdrName': see "RdrName#name_types" +-- +-- * 'Name.Name': see "Name#name_types" +-- +-- * 'Id.Id' represents names that not only have a 'Name.Name' but also a 'TypeRep.Type' and some additional +-- details (a 'IdInfo.IdInfo' and one of 'Var.LocalIdDetails' or 'IdInfo.GlobalIdDetails') that +-- are added, modified and inspected by various compiler passes. These 'Var.Var' names may either +-- be global or local, see "Var#globalvslocal" +-- +-- * 'Var.Var': see "Var#name_types" module Id ( + -- * The main types Id, DictId, - -- Simple construction - mkGlobalId, mkLocalId, mkLocalIdWithInfo, - mkSysLocal, mkUserLocal, mkVanillaGlobal, - mkTemplateLocals, mkTemplateLocalsNum, mkWildId, mkTemplateLocal, - mkWorkerId, mkExportedLocalId, + -- ** Simple construction + mkGlobalId, mkVanillaGlobal, mkVanillaGlobalWithInfo, + mkLocalId, mkLocalIdWithInfo, mkExportedLocalId, + mkSysLocal, mkSysLocalM, mkUserLocal, mkUserLocalM, + mkTemplateLocals, mkTemplateLocalsNum, mkTemplateLocal, + mkWorkerId, - -- Taking an Id apart - idName, idType, idUnique, idInfo, - isId, globalIdDetails, idPrimRep, + -- ** Taking an Id apart + idName, idType, idUnique, idInfo, idDetails, + isId, idPrimRep, recordSelectorFieldLabel, - -- Modifying an Id - setIdName, setIdUnique, Id.setIdType, setIdExported, setIdNotExported, + -- ** Modifying an Id + setIdName, setIdUnique, Id.setIdType, + setIdExported, setIdNotExported, + globaliseId, localiseId, setIdInfo, lazySetIdInfo, modifyIdInfo, maybeModifyIdInfo, - zapLamIdInfo, zapDemandIdInfo, zapFragileIdInfo, + zapLamIdInfo, zapDemandIdInfo, zapFragileIdInfo, transferPolyIdInfo, + - -- Predicates + -- ** Predicates on Ids isImplicitId, isDeadBinder, isDictId, isStrictId, isExportedId, isLocalId, isGlobalId, isRecordSelector, isNaughtyRecordSelector, @@ -39,37 +53,19 @@ module Id ( isPrimOpId, isPrimOpId_maybe, isFCallId, isFCallId_maybe, isDataConWorkId, isDataConWorkId_maybe, isDataConId_maybe, idDataCon, - isBottomingId, idIsFrom, + isConLikeId, isBottomingId, idIsFrom, isTickBoxOp, isTickBoxOp_maybe, hasNoBinding, - -- Inline pragma stuff - idInlinePragma, setInlinePragma, modifyInlinePragma, - + -- ** Inline pragma stuff + idInlinePragma, setInlinePragma, modifyInlinePragma, + idInlineActivation, setInlineActivation, idRuleMatchInfo, - -- One shot lambda stuff + -- ** One-shot lambdas isOneShotBndr, isOneShotLambda, isStateHackType, setOneShotLambda, clearOneShotLambda, - -- IdInfo stuff - setIdUnfolding, - setIdArity, - setIdNewDemandInfo, - setIdNewStrictness, zapIdNewStrictness, - setIdWorkerInfo, - setIdSpecialisation, - setIdCafInfo, - setIdOccInfo, - -#ifdef OLD_STRICTNESS - idDemandInfo, - idStrictness, - idCprInfo, - setIdStrictness, - setIdDemandInfo, - setIdCprInfo, -#endif - + -- ** Reading 'IdInfo' fields idArity, idNewDemandInfo, idNewDemandInfo_maybe, idNewStrictness, idNewStrictness_maybe, @@ -81,22 +77,45 @@ module Id ( idOccInfo, #ifdef OLD_STRICTNESS - newStrictnessFromOld -- Temporary + idDemandInfo, + idStrictness, + idCprInfo, #endif + -- ** Writing 'IdInfo' fields + setIdUnfolding, + setIdArity, + setIdNewDemandInfo, + setIdNewStrictness, zapIdNewStrictness, + setIdWorkerInfo, + setIdSpecialisation, + setIdCafInfo, + setIdOccInfo, zapIdOccInfo, + +#ifdef OLD_STRICTNESS + setIdStrictness, + setIdDemandInfo, + setIdCprInfo, +#endif ) where #include "HsVersions.h" -import CoreSyn +import CoreSyn ( CoreRule, Unfolding ) + +import IdInfo import BasicTypes + +-- Imported and re-exported +import Var( Var, Id, DictId, + idInfo, idDetails, globaliseId, + isId, isLocalId, isGlobalId, isExportedId ) import qualified Var -import Var hiding (mkLocalId, mkGlobalId, mkExportedLocalId) + import TyCon import Type import TcType import TysPrim -import IdInfo #ifdef OLD_STRICTNESS import qualified Demand #endif @@ -104,12 +123,17 @@ import DataCon import NewDemand import Name import Module +import Class +import PrimOp +import ForeignCall import OccName import Maybes import SrcLoc import Outputable import Unique +import UniqSupply import FastString +import Util( count ) import StaticFlags -- infixl so you can say (id `set` a `set` b) @@ -128,7 +152,68 @@ infixl 1 `setIdUnfolding`, #endif \end{code} +%************************************************************************ +%* * +\subsection{Basic Id manipulation} +%* * +%************************************************************************ + +\begin{code} +idName :: Id -> Name +idName = Var.varName + +idUnique :: Id -> Unique +idUnique = Var.varUnique + +idType :: Id -> Kind +idType = Var.varType + +idPrimRep :: Id -> PrimRep +idPrimRep id = typePrimRep (idType id) + +setIdName :: Id -> Name -> Id +setIdName = Var.setVarName + +setIdUnique :: Id -> Unique -> Id +setIdUnique = Var.setVarUnique + +-- | Not only does this set the 'Id' 'Type', it also evaluates the type to try and +-- reduce space usage +setIdType :: Id -> Type -> Id +setIdType id ty = seqType ty `seq` Var.setVarType id ty + +setIdExported :: Id -> Id +setIdExported = Var.setIdExported + +setIdNotExported :: Id -> Id +setIdNotExported = Var.setIdNotExported + +localiseId :: Id -> Id +-- Make an with the same unique and type as the +-- incoming Id, but with an *Internal* Name and *LocalId* flavour +localiseId id + | isLocalId id && isInternalName name + = id + | otherwise + = mkLocalIdWithInfo (localiseName name) (idType id) (idInfo id) + where + name = idName id + +lazySetIdInfo :: Id -> IdInfo -> Id +lazySetIdInfo = Var.lazySetIdInfo + +setIdInfo :: Id -> IdInfo -> Id +setIdInfo id info = seqIdInfo info `seq` (lazySetIdInfo id info) + -- Try to avoid spack leaks by seq'ing + +modifyIdInfo :: (IdInfo -> IdInfo) -> Id -> Id +modifyIdInfo fn id = setIdInfo id (fn (idInfo id)) +-- maybeModifyIdInfo tries to avoid unnecesary thrashing +maybeModifyIdInfo :: Maybe IdInfo -> Id -> Id +maybeModifyIdInfo (Just new_info) id = lazySetIdInfo id new_info +maybeModifyIdInfo Nothing id = id +\end{code} %************************************************************************ %* * @@ -140,32 +225,61 @@ Absolutely all Ids are made by mkId. It is just like Var.mkId, but in addition it pins free-tyvar-info onto the Id's type, where it can easily be found. +Note [Free type variables] +~~~~~~~~~~~~~~~~~~~~~~~~~~ +At one time we cached the free type variables of the type of an Id +at the root of the type in a TyNote. The idea was to avoid repeating +the free-type-variable calculation. But it turned out to slow down +the compiler overall. I don't quite know why; perhaps finding free +type variables of an Id isn't all that common whereas applying a +substitution (which changes the free type variables) is more common. +Anyway, we removed it in March 2008. + \begin{code} -mkLocalIdWithInfo :: Name -> Type -> IdInfo -> Id -mkLocalIdWithInfo name ty info = Var.mkLocalId name (addFreeTyVars ty) info +-- | For an explanation of global vs. local 'Id's, see "Var#globalvslocal" +mkGlobalId :: IdDetails -> Name -> Type -> IdInfo -> Id +mkGlobalId = Var.mkGlobalVar -mkExportedLocalId :: Name -> Type -> Id -mkExportedLocalId name ty = Var.mkExportedLocalId name (addFreeTyVars ty) vanillaIdInfo +-- | Make a global 'Id' without any extra information at all +mkVanillaGlobal :: Name -> Type -> Id +mkVanillaGlobal name ty = mkVanillaGlobalWithInfo name ty vanillaIdInfo -mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id -mkGlobalId details name ty info = Var.mkGlobalId details name (addFreeTyVars ty) info -\end{code} +-- | Make a global 'Id' with no global information but some generic 'IdInfo' +mkVanillaGlobalWithInfo :: Name -> Type -> IdInfo -> Id +mkVanillaGlobalWithInfo = mkGlobalId VanillaId -\begin{code} + +-- | For an explanation of global vs. local 'Id's, see "Var#globalvslocal" mkLocalId :: Name -> Type -> Id mkLocalId name ty = mkLocalIdWithInfo name ty vanillaIdInfo --- SysLocal: for an Id being created by the compiler out of thin air... +mkLocalIdWithInfo :: Name -> Type -> IdInfo -> Id +mkLocalIdWithInfo name ty info = Var.mkLocalVar VanillaId name ty info + -- Note [Free type variables] + +-- | Create a local 'Id' that is marked as exported. +-- This prevents things attached to it from being removed as dead code. +mkExportedLocalId :: Name -> Type -> Id +mkExportedLocalId name ty = Var.mkExportedLocalVar VanillaId name ty vanillaIdInfo + -- Note [Free type variables] + + +-- | Create a system local 'Id'. These are local 'Id's (see "Var#globalvslocal") +-- that are created by the compiler out of thin air mkSysLocal :: FastString -> Unique -> Type -> Id mkSysLocal fs uniq ty = mkLocalId (mkSystemVarName uniq fs) ty +mkSysLocalM :: MonadUnique m => FastString -> Type -> m Id +mkSysLocalM fs ty = getUniqueM >>= (\uniq -> return (mkSysLocal fs uniq ty)) --- UserLocal: an Id with a name the user might recognize... + +-- | Create a user local 'Id'. These are local 'Id's (see "Var#globalvslocal") with a name and location that the user might recognize mkUserLocal :: OccName -> Unique -> Type -> SrcSpan -> Id -mkVanillaGlobal :: Name -> Type -> IdInfo -> Id +mkUserLocal occ uniq ty loc = mkLocalId (mkInternalName uniq occ loc) ty + +mkUserLocalM :: MonadUnique m => OccName -> Type -> SrcSpan -> m Id +mkUserLocalM occ ty loc = getUniqueM >>= (\uniq -> return (mkUserLocal occ uniq ty loc)) -mkUserLocal occ uniq ty loc = mkLocalId (mkInternalName uniq occ loc) ty -mkVanillaGlobal = mkGlobalId VanillaGlobal \end{code} Make some local @Ids@ for a template @CoreExpr@. These have bogus @@ -173,43 +287,24 @@ Make some local @Ids@ for a template @CoreExpr@. These have bogus instantiated before use. \begin{code} --- "Wild Id" typically used when you need a binder that you don't expect to use -mkWildId :: Type -> Id -mkWildId ty = mkSysLocal FSLIT("wild") (mkBuiltinUnique 1) ty - +-- | Workers get local names. "CoreTidy" will externalise these if necessary mkWorkerId :: Unique -> Id -> Type -> Id --- A worker gets a local name. CoreTidy will externalise it if necessary. mkWorkerId uniq unwrkr ty = mkLocalId wkr_name ty where wkr_name = mkInternalName uniq (mkWorkerOcc (getOccName unwrkr)) (getSrcSpan unwrkr) --- "Template locals" typically used in unfoldings +-- | Create a /template local/: a family of system local 'Id's in bijection with @Int@s, typically used in unfoldings +mkTemplateLocal :: Int -> Type -> Id +mkTemplateLocal i ty = mkSysLocal (fsLit "tpl") (mkBuiltinUnique i) ty + +-- | Create a template local for a series of types mkTemplateLocals :: [Type] -> [Id] -mkTemplateLocals tys = zipWith mkTemplateLocal [1..] tys +mkTemplateLocals = mkTemplateLocalsNum 1 +-- | Create a template local for a series of type, but start from a specified template local mkTemplateLocalsNum :: Int -> [Type] -> [Id] --- The Int gives the starting point for unique allocation mkTemplateLocalsNum n tys = zipWith mkTemplateLocal [n..] tys - -mkTemplateLocal :: Int -> Type -> Id -mkTemplateLocal i ty = mkSysLocal FSLIT("tpl") (mkBuiltinUnique i) ty -\end{code} - - -%************************************************************************ -%* * -\subsection[Id-general-funs]{General @Id@-related functions} -%* * -%************************************************************************ - -\begin{code} -setIdType :: Id -> Type -> Id - -- Add free tyvar info to the type -setIdType id ty = seqType ty `seq` Var.setIdType id (addFreeTyVars ty) - -idPrimRep :: Id -> PrimRep -idPrimRep id = typePrimRep (idType id) \end{code} @@ -220,102 +315,126 @@ idPrimRep id = typePrimRep (idType id) %************************************************************************ \begin{code} +-- | If the 'Id' is that for a record selector, extract the 'sel_tycon' and label. Panic otherwise recordSelectorFieldLabel :: Id -> (TyCon, FieldLabel) recordSelectorFieldLabel id - = case globalIdDetails id of - RecordSelId { sel_tycon = tycon, sel_label = lbl } -> (tycon,lbl) - other -> panic "recordSelectorFieldLabel" - -isRecordSelector id = case globalIdDetails id of - RecordSelId {} -> True - other -> False - -isNaughtyRecordSelector id = case globalIdDetails id of - RecordSelId { sel_naughty = n } -> n - other -> False - -isClassOpId_maybe id = case globalIdDetails id of + = case Var.idDetails id of + RecSelId { sel_tycon = tycon } -> (tycon, idName id) + _ -> panic "recordSelectorFieldLabel" + +isRecordSelector :: Id -> Bool +isNaughtyRecordSelector :: Id -> Bool +isPrimOpId :: Id -> Bool +isFCallId :: Id -> Bool +isDataConWorkId :: Id -> Bool + +isClassOpId_maybe :: Id -> Maybe Class +isPrimOpId_maybe :: Id -> Maybe PrimOp +isFCallId_maybe :: Id -> Maybe ForeignCall +isDataConWorkId_maybe :: Id -> Maybe DataCon + +isRecordSelector id = case Var.idDetails id of + RecSelId {} -> True + _ -> False + +isNaughtyRecordSelector id = case Var.idDetails id of + RecSelId { sel_naughty = n } -> n + _ -> False + +isClassOpId_maybe id = case Var.idDetails id of ClassOpId cls -> Just cls _other -> Nothing -isPrimOpId id = case globalIdDetails id of - PrimOpId op -> True - other -> False +isPrimOpId id = case Var.idDetails id of + PrimOpId _ -> True + _ -> False -isPrimOpId_maybe id = case globalIdDetails id of - PrimOpId op -> Just op - other -> Nothing +isPrimOpId_maybe id = case Var.idDetails id of + PrimOpId op -> Just op + _ -> Nothing -isFCallId id = case globalIdDetails id of - FCallId call -> True - other -> False +isFCallId id = case Var.idDetails id of + FCallId _ -> True + _ -> False -isFCallId_maybe id = case globalIdDetails id of - FCallId call -> Just call - other -> Nothing +isFCallId_maybe id = case Var.idDetails id of + FCallId call -> Just call + _ -> Nothing -isDataConWorkId id = case globalIdDetails id of - DataConWorkId _ -> True - other -> False +isDataConWorkId id = case Var.idDetails id of + DataConWorkId _ -> True + _ -> False -isDataConWorkId_maybe id = case globalIdDetails id of - DataConWorkId con -> Just con - other -> Nothing +isDataConWorkId_maybe id = case Var.idDetails id of + DataConWorkId con -> Just con + _ -> Nothing isDataConId_maybe :: Id -> Maybe DataCon -isDataConId_maybe id = case globalIdDetails id of - DataConWorkId con -> Just con - DataConWrapId con -> Just con - other -> Nothing +isDataConId_maybe id = case Var.idDetails id of + DataConWorkId con -> Just con + DataConWrapId con -> Just con + _ -> Nothing idDataCon :: Id -> DataCon --- Get from either the worker or the wrapper to the DataCon --- Currently used only in the desugarer --- INVARIANT: idDataCon (dataConWrapId d) = d --- (Remember, dataConWrapId can return either the wrapper or the worker.) -idDataCon id = case globalIdDetails id of - DataConWorkId con -> con - DataConWrapId con -> con - other -> pprPanic "idDataCon" (ppr id) +-- ^ Get from either the worker or the wrapper 'Id' to the 'DataCon'. Currently used only in the desugarer. +-- +-- INVARIANT: @idDataCon (dataConWrapId d) = d@: remember, 'dataConWrapId' can return either the wrapper or the worker +idDataCon id = isDataConId_maybe id `orElse` pprPanic "idDataCon" (ppr id) isDictId :: Id -> Bool isDictId id = isDictTy (idType id) --- hasNoBinding returns True of an Id which may not have a --- binding, even though it is defined in this module. +hasNoBinding :: Id -> Bool +-- ^ Returns @True@ of an 'Id' which may not have a +-- binding, even though it is defined in this module. + -- Data constructor workers used to be things of this kind, but -- they aren't any more. Instead, we inject a binding for -- them at the CorePrep stage. -- EXCEPT: unboxed tuples, which definitely have no binding -hasNoBinding id = case globalIdDetails id of - PrimOpId _ -> True +hasNoBinding id = case Var.idDetails id of + PrimOpId _ -> True -- See Note [Primop wrappers] FCallId _ -> True DataConWorkId dc -> isUnboxedTupleCon dc - other -> False + _ -> False isImplicitId :: Id -> Bool - -- isImplicitId tells whether an Id's info is implied by other - -- declarations, so we don't need to put its signature in an interface - -- file, even if it's mentioned in some other interface unfolding. +-- ^ 'isImplicitId' tells whether an 'Id's info is implied by other +-- declarations, so we don't need to put its signature in an interface +-- file, even if it's mentioned in some other interface unfolding. isImplicitId id - = case globalIdDetails id of - RecordSelId {} -> True + = case Var.idDetails id of FCallId _ -> True + ClassOpId _ -> True PrimOpId _ -> True - ClassOpId _ -> True DataConWorkId _ -> True DataConWrapId _ -> True -- These are are implied by their type or class decl; -- remember that all type and class decls appear in the interface file. -- The dfun id is not an implicit Id; it must *not* be omitted, because -- it carries version info for the instance decl - other -> False + _ -> False idIsFrom :: Module -> Id -> Bool idIsFrom mod id = nameIsLocalOrFrom mod (idName id) \end{code} +Note [Primop wrappers] +~~~~~~~~~~~~~~~~~~~~~~ +Currently hasNoBinding claims that PrimOpIds don't have a curried +function definition. But actually they do, in GHC.PrimopWrappers, +which is auto-generated from prelude/primops.txt.pp. So actually, hasNoBinding +could return 'False' for PrimOpIds. + +But we'd need to add something in CoreToStg to swizzle any unsaturated +applications of GHC.Prim.plusInt# to GHC.PrimopWrappers.plusInt#. + +Nota Bene: GHC.PrimopWrappers is needed *regardless*, because it's +used by GHCi, which does not implement primops direct at all. + + + \begin{code} isDeadBinder :: Id -> Bool isDeadBinder bndr | isId bndr = isDeadOcc (idOccInfo bndr) @@ -325,13 +444,13 @@ isDeadBinder bndr | isId bndr = isDeadOcc (idOccInfo bndr) \begin{code} isTickBoxOp :: Id -> Bool isTickBoxOp id = - case globalIdDetails id of - TickBoxOpId tick -> True + case Var.idDetails id of + TickBoxOpId _ -> True _ -> False isTickBoxOp_maybe :: Id -> Maybe TickBoxOp isTickBoxOp_maybe id = - case globalIdDetails id of + case Var.idDetails id of TickBoxOpId tick -> Just tick _ -> Nothing \end{code} @@ -361,7 +480,7 @@ setIdStrictness :: Id -> StrictnessInfo -> Id setIdStrictness id strict_info = modifyIdInfo (`setStrictnessInfo` strict_info) id #endif --- isBottomingId returns true if an application to n args would diverge +-- | Returns true if an application to n args would diverge isBottomingId :: Id -> Bool isBottomingId id = isBottomingSig (idNewStrictness id) @@ -376,15 +495,13 @@ setIdNewStrictness id sig = modifyIdInfo (`setNewStrictnessInfo` Just sig) id zapIdNewStrictness :: Id -> Id zapIdNewStrictness id = modifyIdInfo (`setNewStrictnessInfo` Nothing) id -\end{code} -This predicate says whether the id has a strict demand placed on it or -has a type such that it can always be evaluated strictly (e.g., an -unlifted type, but see the comment for isStrictType). We need to -check separately whether has a so-called "strict type" because if -the demand for hasn't been computed yet but has a strict -type, we still want (isStrictId ) to be True. -\begin{code} +-- | This predicate says whether the 'Id' has a strict demand placed on it or +-- has a type such that it can always be evaluated strictly (e.g., an +-- unlifted type, but see the comment for 'isStrictType'). We need to +-- check separately whether the 'Id' has a so-called \"strict type\" because if +-- the demand for the given @id@ hasn't been computed yet but @id@ has a strict +-- type, we still want @isStrictId id@ to be @True@. isStrictId :: Id -> Bool isStrictId id = ASSERT2( isId id, text "isStrictId: not an id: " <+> ppr id ) @@ -471,6 +588,9 @@ idOccInfo id = occInfo (idInfo id) setIdOccInfo :: Id -> OccInfo -> Id setIdOccInfo id occ_info = modifyIdInfo (`setOccInfo` occ_info) id + +zapIdOccInfo :: Id -> Id +zapIdOccInfo b = b `setIdOccInfo` NoOccInfo \end{code} @@ -480,14 +600,26 @@ The inline pragma tells us to be very keen to inline this Id, but it's still OK not to if optimisation is switched off. \begin{code} -idInlinePragma :: Id -> InlinePragInfo +idInlinePragma :: Id -> InlinePragma idInlinePragma id = inlinePragInfo (idInfo id) -setInlinePragma :: Id -> InlinePragInfo -> Id +setInlinePragma :: Id -> InlinePragma -> Id setInlinePragma id prag = modifyIdInfo (`setInlinePragInfo` prag) id -modifyInlinePragma :: Id -> (InlinePragInfo -> InlinePragInfo) -> Id +modifyInlinePragma :: Id -> (InlinePragma -> InlinePragma) -> Id modifyInlinePragma id fn = modifyIdInfo (\info -> info `setInlinePragInfo` (fn (inlinePragInfo info))) id + +idInlineActivation :: Id -> Activation +idInlineActivation id = inlinePragmaActivation (idInlinePragma id) + +setInlineActivation :: Id -> Activation -> Id +setInlineActivation id act = modifyInlinePragma id (\(InlinePragma _ match_info) -> InlinePragma act match_info) + +idRuleMatchInfo :: Id -> RuleMatchInfo +idRuleMatchInfo id = inlinePragmaRuleMatchInfo (idInlinePragma id) + +isConLikeId :: Id -> Bool +isConLikeId id = isDataConWorkId id || isConLike (idRuleMatchInfo id) \end{code} @@ -497,11 +629,15 @@ modifyInlinePragma id fn = modifyIdInfo (\info -> info `setInlinePragInfo` (fn ( idLBVarInfo :: Id -> LBVarInfo idLBVarInfo id = lbvarInfo (idInfo id) +-- | Returns whether the lambda associated with the 'Id' is certainly applied at most once +-- OR we are applying the \"state hack\" which makes it appear as if theis is the case for +-- lambdas used in @IO@. You should prefer using this over 'isOneShotLambda' isOneShotBndr :: Id -> Bool -- This one is the "business end", called externally. -- Its main purpose is to encapsulate the Horrible State Hack isOneShotBndr id = isOneShotLambda id || isStateHackType (idType id) +-- | Should we apply the state hack to values of this 'Type'? isStateHackType :: Type -> Bool isStateHackType ty | opt_NoStateHack @@ -509,7 +645,7 @@ isStateHackType ty | otherwise = case splitTyConApp_maybe ty of Just (tycon,_) -> tycon == statePrimTyCon - other -> False + _ -> False -- This is a gross hack. It claims that -- every function over realWorldStatePrimTy is a one-shot -- function. This is pretty true in practice, and makes a big @@ -529,7 +665,8 @@ isStateHackType ty -- spot that fill_in has arity 2 (and when Keith is done, we will) but we can't yet. --- The OneShotLambda functions simply fiddle with the IdInfo flag +-- | Returns whether the lambda associated with the 'Id' is certainly applied at most once. +-- You probably want to use 'isOneShotBndr' instead isOneShotLambda :: Id -> Bool isOneShotLambda id = case idLBVarInfo id of IsOneShotLambda -> True @@ -543,6 +680,7 @@ clearOneShotLambda id | isOneShotLambda id = modifyIdInfo (`setLBVarInfo` NoLBVarInfo) id | otherwise = id +-- The OneShotLambda functions simply fiddle with the IdInfo flag -- But watch out: this may change the type of something else -- f = \x -> e -- If we change the one-shot-ness of x, f's type changes @@ -555,9 +693,65 @@ zapInfo zapper id = maybeModifyIdInfo (zapper (idInfo id)) id zapLamIdInfo :: Id -> Id zapLamIdInfo = zapInfo zapLamInfo +zapDemandIdInfo :: Id -> Id zapDemandIdInfo = zapInfo zapDemandInfo zapFragileIdInfo :: Id -> Id zapFragileIdInfo = zapInfo zapFragileInfo \end{code} +Note [transferPolyIdInfo] +~~~~~~~~~~~~~~~~~~~~~~~~~ +Suppose we have + + f = /\a. let g = rhs in ... + +where g has interesting strictness information. Then if we float thus + + g' = /\a. rhs + f = /\a. ...[g' a/g] + +we *do not* want to lose g's + * strictness information + * arity + * inline pragma (though that is bit more debatable) + +It's simple to retain strictness and arity, but not so simple to retain + * worker info + * rules +so we simply discard those. Sooner or later this may bite us. + +This transfer is used in two places: + FloatOut (long-distance let-floating) + SimplUtils.abstractFloats (short-distance let-floating) + +If we abstract wrt one or more *value* binders, we must modify the +arity and strictness info before transferring it. E.g. + f = \x. e +--> + g' = \y. \x. e + + substitute (g' y) for g +Notice that g' has an arity one more than the original g + +\begin{code} +transferPolyIdInfo :: Id -- Original Id + -> [Var] -- Abstract wrt these variables + -> Id -- New Id + -> Id +transferPolyIdInfo old_id abstract_wrt new_id + = modifyIdInfo transfer new_id + where + arity_increase = count isId abstract_wrt -- Arity increases by the + -- number of value binders + + old_info = idInfo old_id + old_arity = arityInfo old_info + old_inline_prag = inlinePragInfo old_info + new_arity = old_arity + arity_increase + old_strictness = newStrictnessInfo old_info + new_strictness = fmap (increaseStrictSigArity arity_increase) old_strictness + + transfer new_info = new_info `setNewStrictnessInfo` new_strictness + `setArityInfo` new_arity + `setInlinePragInfo` old_inline_prag +\end{code}