X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FId.lhs;h=5ac261255cb787d280a1bd86395b24d2622b6076;hp=cb2422d20bc427a7987fc9cc77bb617bfffb88f2;hb=914e415702a25a6e52ab1eaaf2aea233d6c6097e;hpb=2e3b6bd7e00fa3faaa07ea0badee7f020a7c8306 diff --git a/compiler/basicTypes/Id.lhs b/compiler/basicTypes/Id.lhs index cb2422d..5ac2612 100644 --- a/compiler/basicTypes/Id.lhs +++ b/compiler/basicTypes/Id.lhs @@ -5,126 +5,198 @@ \section[Id]{@Ids@: Value and constructor identifiers} \begin{code} +-- | +-- #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 ( - Id, DictId, - - -- Simple construction - mkGlobalId, mkLocalId, mkLocalIdWithInfo, - mkSysLocal, mkUserLocal, mkVanillaGlobal, - mkTemplateLocals, mkTemplateLocalsNum, mkWildId, mkTemplateLocal, - mkWorkerId, mkExportedLocalId, - - -- Taking an Id apart - idName, idType, idUnique, idInfo, - isId, globalIdDetails, idPrimRep, - recordSelectorFieldLabel, - - -- Modifying an Id - setIdName, setIdUnique, Id.setIdType, setIdExported, setIdNotExported, + -- * The main types + Var, Id, isId, + + -- ** Simple construction + mkGlobalId, mkVanillaGlobal, mkVanillaGlobalWithInfo, + mkLocalId, mkLocalIdWithInfo, mkExportedLocalId, + mkSysLocal, mkSysLocalM, mkUserLocal, mkUserLocalM, + mkTemplateLocals, mkTemplateLocalsNum, mkTemplateLocal, + mkWorkerId, mkWiredInIdName, + + -- ** Taking an Id apart + idName, idType, idUnique, idInfo, idDetails, + idPrimRep, recordSelectorFieldLabel, + + -- ** Modifying an Id + setIdName, setIdUnique, Id.setIdType, + setIdExported, setIdNotExported, + globaliseId, localiseId, setIdInfo, lazySetIdInfo, modifyIdInfo, maybeModifyIdInfo, - zapLamIdInfo, zapDemandIdInfo, zapFragileIdInfo, + zapLamIdInfo, zapDemandIdInfo, zapFragileIdInfo, transferPolyIdInfo, + - -- Predicates - isImplicitId, isDeadBinder, isDictId, isStrictId, + -- ** Predicates on Ids + isImplicitId, isDeadBinder, + isStrictId, isExportedId, isLocalId, isGlobalId, isRecordSelector, isNaughtyRecordSelector, - isClassOpId_maybe, + isClassOpId_maybe, isDFunId, dfunNSilent, 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, + -- ** Evidence variables + DictId, isDictId, isEvVar, evVarPred, + -- ** 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, - idWorkerInfo, - idUnfolding, + idDemandInfo, idDemandInfo_maybe, + idStrictness, idStrictness_maybe, + idUnfolding, realIdUnfolding, idSpecialisation, idCoreRules, idHasRules, idCafInfo, idLBVarInfo, idOccInfo, -#ifdef OLD_STRICTNESS - newStrictnessFromOld -- Temporary -#endif + -- ** Writing 'IdInfo' fields + setIdUnfoldingLazily, + setIdUnfolding, + setIdArity, + setIdDemandInfo, + setIdStrictness, zapIdStrictness, + setIdSpecialisation, + setIdCafInfo, + setIdOccInfo, zapIdOccInfo, ) where #include "HsVersions.h" -import CoreSyn +import CoreSyn ( CoreRule, Unfolding( NoUnfolding ) ) + +import IdInfo import BasicTypes + +-- Imported and re-exported +import Var( Var, Id, DictId, EvVar, + idInfo, idDetails, globaliseId, varType, + 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 import DataCon -import NewDemand +import Demand 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) -infixl 1 `setIdUnfolding`, +infixl 1 `setIdUnfoldingLazily`, + `setIdUnfolding`, `setIdArity`, - `setIdNewDemandInfo`, - `setIdNewStrictness`, - `setIdWorkerInfo`, + `setIdOccInfo`, + `setIdDemandInfo`, + `setIdStrictness`, `setIdSpecialisation`, `setInlinePragma`, + `setInlineActivation`, `idCafInfo` -#ifdef OLD_STRICTNESS - ,`idCprInfo` - ,`setIdStrictness` - ,`setIdDemandInfo` -#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 + | ASSERT( isId 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} %************************************************************************ %* * @@ -136,32 +208,64 @@ 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 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 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 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 +mkWiredInIdName :: Module -> FastString -> Unique -> Id -> Name +mkWiredInIdName mod fs uniq id + = mkWiredInName mod (mkOccNameFS varName fs) uniq (AnId id) UserSyntax \end{code} Make some local @Ids@ for a template @CoreExpr@. These have bogus @@ -169,43 +273,22 @@ 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) + = mkLocalId (mkDerivedInternalName mkWorkerOcc uniq (getName unwrkr)) ty + +-- | 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 --- "Template locals" typically used in unfoldings +-- | 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 ty - -idPrimRep :: Id -> PrimRep -idPrimRep id = typePrimRep (idType id) \end{code} @@ -216,104 +299,107 @@ 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) + = case Var.idDetails id of + RecSelId { sel_tycon = tycon } -> (tycon, idName id) _ -> panic "recordSelectorFieldLabel" -isRecordSelector :: Var -> Bool -isNaughtyRecordSelector :: Var -> Bool -isPrimOpId :: Var -> Bool -isFCallId :: Var -> Bool -isDataConWorkId :: Var -> Bool -hasNoBinding :: Var -> Bool +isRecordSelector :: Id -> Bool +isNaughtyRecordSelector :: Id -> Bool +isPrimOpId :: Id -> Bool +isFCallId :: Id -> Bool +isDataConWorkId :: Id -> Bool +isDFunId :: Id -> Bool -isClassOpId_maybe :: Var -> Maybe Class -isPrimOpId_maybe :: Var -> Maybe PrimOp -isFCallId_maybe :: Var -> Maybe ForeignCall -isDataConWorkId_maybe :: Var -> Maybe DataCon +isClassOpId_maybe :: Id -> Maybe Class +isPrimOpId_maybe :: Id -> Maybe PrimOp +isFCallId_maybe :: Id -> Maybe ForeignCall +isDataConWorkId_maybe :: Id -> Maybe DataCon -isRecordSelector id = case globalIdDetails id of - RecordSelId {} -> True +isRecordSelector id = case Var.idDetails id of + RecSelId {} -> True _ -> False -isNaughtyRecordSelector id = case globalIdDetails id of - RecordSelId { sel_naughty = n } -> n +isNaughtyRecordSelector id = case Var.idDetails id of + RecSelId { sel_naughty = n } -> n _ -> False -isClassOpId_maybe id = case globalIdDetails id of +isClassOpId_maybe id = case Var.idDetails id of ClassOpId cls -> Just cls _other -> Nothing -isPrimOpId id = case globalIdDetails id of +isPrimOpId id = case Var.idDetails id of PrimOpId _ -> True _ -> False -isPrimOpId_maybe id = case globalIdDetails id of +isDFunId id = case Var.idDetails id of + DFunId {} -> True + _ -> False + +dfunNSilent :: Id -> Int +dfunNSilent id = case Var.idDetails id of + DFunId ns _ -> ns + _ -> pprTrace "dfunSilent: not a dfun:" (ppr id) 0 + +isPrimOpId_maybe id = case Var.idDetails id of PrimOpId op -> Just op _ -> Nothing -isFCallId id = case globalIdDetails id of +isFCallId id = case Var.idDetails id of FCallId _ -> True _ -> False -isFCallId_maybe id = case globalIdDetails id of +isFCallId_maybe id = case Var.idDetails id of FCallId call -> Just call _ -> Nothing -isDataConWorkId id = case globalIdDetails id of +isDataConWorkId id = case Var.idDetails id of DataConWorkId _ -> True _ -> False -isDataConWorkId_maybe id = case globalIdDetails id of +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 +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 - _ -> 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 :: Id -> Bool +-- ^ Returns @True@ of an 'Id' which may not have a +-- binding, even though it is defined in this module. --- hasNoBinding 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 +hasNoBinding id = case Var.idDetails id of PrimOpId _ -> True -- See Note [Primop wrappers] FCallId _ -> True DataConWorkId dc -> isUnboxedTupleCon dc _ -> 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 - FCallId _ -> True - PrimOpId _ -> True - ClassOpId _ -> True - DataConWorkId _ -> True - DataConWrapId _ -> True + = case Var.idDetails id of + FCallId {} -> True + ClassOpId {} -> True + PrimOpId {} -> 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 @@ -348,19 +434,39 @@ isDeadBinder bndr | isId bndr = isDeadOcc (idOccInfo bndr) \begin{code} isTickBoxOp :: Id -> Bool isTickBoxOp id = - case globalIdDetails id of + 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} %************************************************************************ %* * + Evidence variables +%* * +%************************************************************************ + +\begin{code} +isEvVar :: Var -> Bool +isEvVar var = isPredTy (varType var) + +isDictId :: Id -> Bool +isDictId id = isDictTy (idType id) + +evVarPred :: EvVar -> PredType +evVarPred var + = case splitPredTy_maybe (varType var) of + Just pred -> pred + Nothing -> pprPanic "evVarPred" (ppr var <+> ppr (varType var)) +\end{code} + +%************************************************************************ +%* * \subsection{IdInfo stuff} %* * %************************************************************************ @@ -374,83 +480,68 @@ idArity id = arityInfo (idInfo id) setIdArity :: Id -> Arity -> Id setIdArity id arity = modifyIdInfo (`setArityInfo` arity) id -#ifdef OLD_STRICTNESS - --------------------------------- - -- (OLD) STRICTNESS -idStrictness :: Id -> StrictnessInfo -idStrictness id = strictnessInfo (idInfo id) - -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) +isBottomingId id = isBottomingSig (idStrictness id) -idNewStrictness_maybe :: Id -> Maybe StrictSig -idNewStrictness :: Id -> StrictSig +idStrictness_maybe :: Id -> Maybe StrictSig +idStrictness :: Id -> StrictSig -idNewStrictness_maybe id = newStrictnessInfo (idInfo id) -idNewStrictness id = idNewStrictness_maybe id `orElse` topSig +idStrictness_maybe id = strictnessInfo (idInfo id) +idStrictness id = idStrictness_maybe id `orElse` topSig -setIdNewStrictness :: Id -> StrictSig -> Id -setIdNewStrictness id sig = modifyIdInfo (`setNewStrictnessInfo` Just sig) id +setIdStrictness :: Id -> StrictSig -> Id +setIdStrictness id sig = modifyIdInfo (`setStrictnessInfo` Just sig) id -zapIdNewStrictness :: Id -> Id -zapIdNewStrictness id = modifyIdInfo (`setNewStrictnessInfo` Nothing) id -\end{code} +zapIdStrictness :: Id -> Id +zapIdStrictness id = modifyIdInfo (`setStrictnessInfo` Nothing) id -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 ) - (isStrictDmd (idNewDemandInfo id)) || + (isStrictDmd (idDemandInfo id)) || (isStrictType (idType id)) --------------------------------- - -- WORKER ID -idWorkerInfo :: Id -> WorkerInfo -idWorkerInfo id = workerInfo (idInfo id) - -setIdWorkerInfo :: Id -> WorkerInfo -> Id -setIdWorkerInfo id work_info = modifyIdInfo (`setWorkerInfo` work_info) id - - --------------------------------- -- UNFOLDING idUnfolding :: Id -> Unfolding -idUnfolding id = unfoldingInfo (idInfo id) +-- Do not expose the unfolding of a loop breaker! +idUnfolding id + | isNonRuleLoopBreaker (occInfo info) = NoUnfolding + | otherwise = unfoldingInfo info + where + info = idInfo id -setIdUnfolding :: Id -> Unfolding -> Id -setIdUnfolding id unfolding = modifyIdInfo (`setUnfoldingInfo` unfolding) id +realIdUnfolding :: Id -> Unfolding +-- Expose the unfolding if there is one, including for loop breakers +realIdUnfolding id = unfoldingInfo (idInfo id) -#ifdef OLD_STRICTNESS - --------------------------------- - -- (OLD) DEMAND -idDemandInfo :: Id -> Demand.Demand -idDemandInfo id = demandInfo (idInfo id) +setIdUnfoldingLazily :: Id -> Unfolding -> Id +setIdUnfoldingLazily id unfolding = modifyIdInfo (`setUnfoldingInfoLazily` unfolding) id -setIdDemandInfo :: Id -> Demand.Demand -> Id -setIdDemandInfo id demand_info = modifyIdInfo (`setDemandInfo` demand_info) id -#endif +setIdUnfolding :: Id -> Unfolding -> Id +setIdUnfolding id unfolding = modifyIdInfo (`setUnfoldingInfo` unfolding) id -idNewDemandInfo_maybe :: Id -> Maybe NewDemand.Demand -idNewDemandInfo :: Id -> NewDemand.Demand +idDemandInfo_maybe :: Id -> Maybe Demand +idDemandInfo :: Id -> Demand -idNewDemandInfo_maybe id = newDemandInfo (idInfo id) -idNewDemandInfo id = newDemandInfo (idInfo id) `orElse` NewDemand.topDmd +idDemandInfo_maybe id = demandInfo (idInfo id) +idDemandInfo id = demandInfo (idInfo id) `orElse` topDmd -setIdNewDemandInfo :: Id -> NewDemand.Demand -> Id -setIdNewDemandInfo id dmd = modifyIdInfo (`setNewDemandInfo` Just dmd) id +setIdDemandInfo :: Id -> Demand -> Id +setIdDemandInfo id dmd = modifyIdInfo (`setDemandInfo` Just dmd) id --------------------------------- -- SPECIALISATION + +-- See Note [Specialisations and RULES in IdInfo] in IdInfo.lhs + idSpecialisation :: Id -> SpecInfo idSpecialisation id = specInfo (idInfo id) @@ -466,34 +557,21 @@ setIdSpecialisation id spec_info = modifyIdInfo (`setSpecInfo` spec_info) id --------------------------------- -- CAF INFO idCafInfo :: Id -> CafInfo -#ifdef OLD_STRICTNESS -idCafInfo id = case cgInfo (idInfo id) of - NoCgInfo -> pprPanic "idCafInfo" (ppr id) - info -> cgCafInfo info -#else idCafInfo id = cafInfo (idInfo id) -#endif setIdCafInfo :: Id -> CafInfo -> Id setIdCafInfo id caf_info = modifyIdInfo (`setCafInfo` caf_info) id --------------------------------- - -- CPR INFO -#ifdef OLD_STRICTNESS -idCprInfo :: Id -> CprInfo -idCprInfo id = cprInfo (idInfo id) - -setIdCprInfo :: Id -> CprInfo -> Id -setIdCprInfo id cpr_info = modifyIdInfo (`setCprInfo` cpr_info) id -#endif - - --------------------------------- -- Occcurrence INFO idOccInfo :: Id -> OccInfo 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} @@ -503,14 +581,26 @@ 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 (\prag -> setInlinePragmaActivation prag act) + +idRuleMatchInfo :: Id -> RuleMatchInfo +idRuleMatchInfo id = inlinePragmaRuleMatchInfo (idInlinePragma id) + +isConLikeId :: Id -> Bool +isConLikeId id = isDataConWorkId id || isConLike (idRuleMatchInfo id) \end{code} @@ -520,11 +610,15 @@ 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 @@ -552,7 +646,8 @@ 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 @@ -566,6 +661,7 @@ 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 @@ -585,3 +681,75 @@ zapFragileIdInfo :: Id -> Id zapFragileIdInfo = zapInfo zapFragileInfo \end{code} +Note [transferPolyIdInfo] +~~~~~~~~~~~~~~~~~~~~~~~~~ +This transfer is used in two places: + FloatOut (long-distance let-floating) + SimplUtils.abstractFloats (short-distance let-floating) + +Consider the short-distance let-floating: + + f = /\a. let g = rhs in ... + +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) + * occurrence info + +Mostly this is just an optimisation, but it's *vital* to +transfer the occurrence info. Consider + + NonRec { f = /\a. let Rec { g* = ..g.. } in ... } + +where the '*' means 'LoopBreaker'. Then if we float we must get + + Rec { g'* = /\a. ...(g' a)... } + NonRec { f = /\a. ...[g' a/g]....} + +where g' is also marked as LoopBreaker. If not, terrible things +can happen if we re-simplify the binding (and the Simplifier does +sometimes simplify a term twice); see Trac #4345. + +It's not so simple to retain + * worker info + * rules +so we simply discard those. Sooner or later this may bite us. + +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 + old_occ_info = occInfo old_info + new_arity = old_arity + arity_increase + old_strictness = strictnessInfo old_info + new_strictness = fmap (increaseStrictSigArity arity_increase) old_strictness + + transfer new_info = new_info `setStrictnessInfo` new_strictness + `setArityInfo` new_arity + `setInlinePragInfo` old_inline_prag + `setOccInfo` old_occ_info +\end{code}