%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[Id]{@Ids@: Value and constructor identifiers}
-- Modifying an Id
setIdName, setIdUnique, Id.setIdType, setIdExported, setIdNotExported,
setIdInfo, lazySetIdInfo, modifyIdInfo, maybeModifyIdInfo,
- zapLamIdInfo, zapDemandIdInfo,
+ zapLamIdInfo, zapDemandIdInfo, zapFragileIdInfo, transferPolyIdInfo,
-- Predicates
- isImplicitId, isDeadBinder, isDictId,
+ isImplicitId, isDeadBinder, isDictId, isStrictId,
isExportedId, isLocalId, isGlobalId,
isRecordSelector, isNaughtyRecordSelector,
isClassOpId_maybe,
isFCallId, isFCallId_maybe,
isDataConWorkId, isDataConWorkId_maybe, isDataConId_maybe, idDataCon,
isBottomingId, idIsFrom,
+ isTickBoxOp, isTickBoxOp_maybe,
hasNoBinding,
-- Inline pragma stuff
#include "HsVersions.h"
-
-import CoreSyn ( Unfolding, CoreRule )
-import BasicTypes ( Arity )
-import Var ( Id, DictId,
- isId, isExportedId, isLocalId,
- idName, idType, idUnique, idInfo, isGlobalId,
- setIdName, setIdType, setIdUnique,
- setIdExported, setIdNotExported,
- setIdInfo, lazySetIdInfo, modifyIdInfo,
- maybeModifyIdInfo,
- globalIdDetails
- )
-import qualified Var ( mkLocalId, mkGlobalId, mkExportedLocalId )
-import TyCon ( FieldLabel, TyCon )
-import Type ( Type, typePrimRep, addFreeTyVars, seqType,
- splitTyConApp_maybe, PrimRep )
-import TcType ( isDictTy )
-import TysPrim ( statePrimTyCon )
+import CoreSyn
+import BasicTypes
+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 ( Demand )
+import qualified Demand
#endif
-import DataCon ( DataCon, isUnboxedTupleCon )
-import NewDemand ( Demand, StrictSig, topDmd, topSig, isBottomingSig )
-import Name ( Name, OccName, nameIsLocalOrFrom,
- mkSystemVarName, mkInternalName, getOccName,
- getSrcLoc )
-import Module ( Module )
-import OccName ( mkWorkerOcc )
-import Maybes ( orElse )
-import SrcLoc ( SrcLoc )
+import DataCon
+import NewDemand
+import Name
+import Module
+import Class
+import PrimOp
+import ForeignCall
+import OccName
+import Maybes
+import SrcLoc
import Outputable
-import Unique ( Unique, mkBuiltinUnique )
-import FastString ( FastString )
-import StaticFlags ( opt_NoStateHack )
+import Unique
+import FastString
+import StaticFlags
-- infixl so you can say (id `set` a `set` b)
infixl 1 `setIdUnfolding`,
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
+mkLocalIdWithInfo name ty info = Var.mkLocalId name ty info
+ -- Note [Free type variables]
mkExportedLocalId :: Name -> Type -> Id
-mkExportedLocalId name ty = Var.mkExportedLocalId name (addFreeTyVars ty) vanillaIdInfo
+mkExportedLocalId name ty = Var.mkExportedLocalId name ty vanillaIdInfo
+ -- Note [Free type variables]
mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
-mkGlobalId details name ty info = Var.mkGlobalId details name (addFreeTyVars ty) info
+mkGlobalId details name ty info = Var.mkGlobalId details name ty info
\end{code}
\begin{code}
-- UserLocal: an Id with a name the user might recognize...
-mkUserLocal :: OccName -> Unique -> Type -> SrcLoc -> Id
+mkUserLocal :: OccName -> Unique -> Type -> SrcSpan -> Id
mkVanillaGlobal :: Name -> Type -> IdInfo -> Id
mkUserLocal occ uniq ty loc = mkLocalId (mkInternalName uniq occ loc) ty
\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
+mkWildId ty = mkSysLocal (fsLit "wild") (mkBuiltinUnique 1) ty
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)) (getSrcLoc unwrkr)
+ wkr_name = mkInternalName uniq (mkWorkerOcc (getOccName unwrkr)) (getSrcSpan unwrkr)
-- "Template locals" typically used in unfoldings
mkTemplateLocals :: [Type] -> [Id]
mkTemplateLocalsNum n tys = zipWith mkTemplateLocal [n..] tys
mkTemplateLocal :: Int -> Type -> Id
-mkTemplateLocal i ty = mkSysLocal FSLIT("tpl") (mkBuiltinUnique i) ty
+mkTemplateLocal i ty = mkSysLocal (fsLit "tpl") (mkBuiltinUnique i) ty
\end{code}
\begin{code}
setIdType :: Id -> Type -> Id
-- Add free tyvar info to the type
-setIdType id ty = seqType ty `seq` Var.setIdType id (addFreeTyVars ty)
+setIdType id ty = seqType ty `seq` Var.setIdType id ty
idPrimRep :: Id -> PrimRep
idPrimRep id = typePrimRep (idType id)
\begin{code}
recordSelectorFieldLabel :: Id -> (TyCon, FieldLabel)
-recordSelectorFieldLabel id = case globalIdDetails id of
- RecordSelId tycon lbl _ -> (tycon,lbl)
- other -> panic "recordSelectorFieldLabel"
+recordSelectorFieldLabel id
+ = case globalIdDetails id of
+ RecordSelId { sel_tycon = tycon, sel_label = lbl } -> (tycon,lbl)
+ _ -> panic "recordSelectorFieldLabel"
+
+isRecordSelector :: Var -> Bool
+isNaughtyRecordSelector :: Var -> Bool
+isPrimOpId :: Var -> Bool
+isFCallId :: Var -> Bool
+isDataConWorkId :: Var -> Bool
+hasNoBinding :: Var -> Bool
+
+isClassOpId_maybe :: Var -> Maybe Class
+isPrimOpId_maybe :: Var -> Maybe PrimOp
+isFCallId_maybe :: Var -> Maybe ForeignCall
+isDataConWorkId_maybe :: Var -> Maybe DataCon
isRecordSelector id = case globalIdDetails id of
- RecordSelId {} -> True
- other -> False
+ RecordSelId {} -> True
+ _ -> False
isNaughtyRecordSelector id = case globalIdDetails id of
- RecordSelId { sel_naughty = n } -> n
- other -> False
+ RecordSelId { sel_naughty = n } -> n
+ _ -> False
isClassOpId_maybe id = case globalIdDetails id of
ClassOpId cls -> Just cls
_other -> Nothing
isPrimOpId id = case globalIdDetails id of
- PrimOpId op -> True
- other -> False
+ PrimOpId _ -> True
+ _ -> False
isPrimOpId_maybe id = case globalIdDetails id of
- PrimOpId op -> Just op
- other -> Nothing
+ PrimOpId op -> Just op
+ _ -> Nothing
isFCallId id = case globalIdDetails id of
- FCallId call -> True
- other -> False
+ FCallId _ -> True
+ _ -> False
isFCallId_maybe id = case globalIdDetails id of
- FCallId call -> Just call
- other -> Nothing
+ FCallId call -> Just call
+ _ -> Nothing
isDataConWorkId id = case globalIdDetails id of
- DataConWorkId _ -> True
- other -> False
+ DataConWorkId _ -> True
+ _ -> False
isDataConWorkId_maybe id = case globalIdDetails id of
- DataConWorkId con -> Just con
- other -> Nothing
+ 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
+ DataConWorkId con -> Just con
+ DataConWrapId con -> Just con
+ _ -> Nothing
idDataCon :: Id -> DataCon
-- Get from either the worker or the wrapper to the DataCon
-- 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)
+ DataConWorkId con -> con
+ DataConWrapId con -> con
+ _ -> pprPanic "idDataCon" (ppr id)
isDictId :: Id -> Bool
-- them at the CorePrep stage.
-- EXCEPT: unboxed tuples, which definitely have no binding
hasNoBinding id = case globalIdDetails id of
- PrimOpId _ -> True
+ 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
-- 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)
| otherwise = False -- TyVars count as not dead
\end{code}
+\begin{code}
+isTickBoxOp :: Id -> Bool
+isTickBoxOp id =
+ case globalIdDetails id of
+ TickBoxOpId _ -> True
+ _ -> False
+
+isTickBoxOp_maybe :: Id -> Maybe TickBoxOp
+isTickBoxOp_maybe id =
+ case globalIdDetails id of
+ TickBoxOpId tick -> Just tick
+ _ -> Nothing
+\end{code}
%************************************************************************
%* *
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 <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}
+isStrictId :: Id -> Bool
+isStrictId id
+ = ASSERT2( isId id, text "isStrictId: not an id: " <+> ppr id )
+ (isStrictDmd (idNewDemandInfo id)) ||
+ (isStrictType (idType id))
---------------------------------
-- WORKER ID
| 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
\end{code}
\begin{code}
+zapInfo :: (IdInfo -> Maybe IdInfo) -> Id -> Id
+zapInfo zapper id = maybeModifyIdInfo (zapper (idInfo id)) id
+
zapLamIdInfo :: Id -> Id
-zapLamIdInfo id = maybeModifyIdInfo (zapLamInfo (idInfo 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 ...
-zapDemandIdInfo id = maybeModifyIdInfo (zapDemandInfo (idInfo id)) id
+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 the strictness information on g. Nor arity.
+
+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)
+
+\begin{code}
+transferPolyIdInfo :: Id -> Id -> Id
+transferPolyIdInfo old_id 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)
\end{code}
projects / ghc-hetmet.git / blobdiff