\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, 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}
%************************************************************************
%* *
Anyway, we removed it in March 2008.
\begin{code}
+-- | For an explanation of global vs. local 'Id's, see "Var#globalvslocal"
+mkGlobalId :: IdDetails -> Name -> Type -> IdInfo -> Id
+mkGlobalId = Var.mkGlobalVar
+
+-- | Make a global 'Id' without any extra information at all
+mkVanillaGlobal :: Name -> Type -> Id
+mkVanillaGlobal name ty = mkVanillaGlobalWithInfo name ty vanillaIdInfo
+
+-- | Make a global 'Id' with no global information but some generic 'IdInfo'
+mkVanillaGlobalWithInfo :: Name -> Type -> IdInfo -> Id
+mkVanillaGlobalWithInfo = mkGlobalId VanillaId
+
+
+-- | For an explanation of global vs. local 'Id's, see "Var#globalvslocal"
+mkLocalId :: Name -> Type -> Id
+mkLocalId name ty = mkLocalIdWithInfo name ty vanillaIdInfo
+
mkLocalIdWithInfo :: Name -> Type -> IdInfo -> Id
-mkLocalIdWithInfo name ty info = Var.mkLocalId name ty info
+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.mkExportedLocalId name ty vanillaIdInfo
+mkExportedLocalId name ty = Var.mkExportedLocalVar VanillaId name ty vanillaIdInfo
-- Note [Free type variables]
-mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
-mkGlobalId details name ty info = Var.mkGlobalId details name ty info
-\end{code}
-\begin{code}
-mkLocalId :: Name -> Type -> Id
-mkLocalId name ty = mkLocalIdWithInfo name ty vanillaIdInfo
-
--- SysLocal: for an Id being created by the compiler out of thin air...
+-- | 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
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
--- "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 ty
-
-idPrimRep :: Id -> PrimRep
-idPrimRep id = typePrimRep (idType id)
\end{code}
%************************************************************************
\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
\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}
%* *
%************************************************************************
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 <id> has a so-called "strict type" because if
-the demand for <id> hasn't been computed yet but <id> has a strict
-type, we still want (isStrictId <id>) 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)
---------------------------------
-- 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}
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}
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
-- 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
| 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
Note [transferPolyIdInfo]
~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
+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 ...
-where g has interesting strictness information. Then if we float thus
+Then if we float thus
g' = /\a. rhs
- f = /\a. ...[g' a/g]
+ f = /\a. ...[g' a/g]....
-we *do not* want to lose the strictness information on g. Nor arity.
+we *do not* want to lose g's
+ * strictness information
+ * arity
+ * inline pragma (though that is bit more debatable)
+ * occurrence info
-It's simple to retain strictness and arity, but not so simple to retain
- worker info
- rules
+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.
-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 -> Id -> Id
-transferPolyIdInfo old_id new_id
+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
- old_info = idInfo old_id
- transfer new_info = new_info `setNewStrictnessInfo` (newStrictnessInfo old_info)
- `setArityInfo` (arityInfo old_info)
+ 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}
-
projects / ghc-hetmet.git / blobdiff