X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FbasicTypes%2FVar.lhs;h=eec6c803b461be484597a7b8ead612570893820c;hb=a187566d4ce21b657fd5268373d0e3743d29d886;hp=d9cedf0b07fd4c1c0a345751747d65de0fb44cd4;hpb=de400dba4adc3ea9323289594d932410fa8e6419;p=ghc-hetmet.git diff --git a/compiler/basicTypes/Var.lhs b/compiler/basicTypes/Var.lhs index d9cedf0..eec6c80 100644 --- a/compiler/basicTypes/Var.lhs +++ b/compiler/basicTypes/Var.lhs @@ -5,33 +5,72 @@ \section{@Vars@: Variables} \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': see "Id#name_types" +-- +-- * 'Var.Var' is a synonym for the 'Id.Id' type but it may additionally potentially contain type variables, +-- which have a 'TypeRep.Kind' rather than a 'TypeRep.Type' and only contain some extra details during typechecking. +-- These 'Var.Var' names may either be global or local, see "Var#globalvslocal" +-- +-- #globalvslocal# +-- Global 'Id's and 'Var's are those that are imported or correspond to a data constructor, primitive operation, or record selectors. +-- Local 'Id's and 'Var's are those bound within an expression (e.g. by a lambda) or at the top level of the module being compiled. module Var ( - Var, - varName, varUnique, varType, - setVarName, setVarUnique, + -- * The main data type + Var, - -- TyVars - TyVar, mkTyVar, mkTcTyVar, mkWildCoVar, - tyVarName, tyVarKind, + -- ** Constructing 'Var's + mkLocalIdVar, mkExportedLocalIdVar, mkGlobalIdVar, + + -- ** Taking 'Var's apart + varName, varUnique, varType, varIdInfo, globalIdVarDetails, + + -- ** Modifying 'Var's + setVarName, setVarUnique, setVarType, + setIdVarExported, setIdVarNotExported, + globaliseIdVar, lazySetVarIdInfo, + + -- ** Predicates + isCoVar, isIdVar, isTyVar, isTcTyVar, + isLocalVar, isLocalIdVar, + isGlobalIdVar, isExportedIdVar, + mustHaveLocalBinding, + + -- * Type variable data type + TyVar, + + -- ** Constructing 'TyVar's + mkTyVar, mkTcTyVar, mkWildCoVar, + + -- ** Taking 'TyVar's apart + tyVarName, tyVarKind, tcTyVarDetails, + + -- ** Modifying 'TyVar's setTyVarName, setTyVarUnique, setTyVarKind, - tcTyVarDetails, - -- CoVars - CoVar, coVarName, setCoVarUnique, setCoVarName, mkCoVar, isCoVar, + -- * Coercion variable data type + CoVar, - -- Ids - Id, DictId, - idName, idType, idUnique, idInfo, modifyIdInfo, maybeModifyIdInfo, - setIdName, setIdUnique, setIdType, setIdInfo, lazySetIdInfo, - setIdExported, setIdNotExported, + -- ** Constructing 'CoVar's + mkCoVar, - globalIdDetails, globaliseId, + -- ** Taking 'CoVar's apart + coVarName, - mkLocalId, mkExportedLocalId, mkGlobalId, + -- ** Modifying 'CoVar's + setCoVarUnique, setCoVarName, - isTyVar, isTcTyVar, isId, isLocalVar, isLocalId, - isGlobalId, isExportedId, - mustHaveLocalBinding + -- * 'Var' type synonyms + Id, DictId ) where #include "HsVersions.h" @@ -39,14 +78,14 @@ module Var ( import {-# SOURCE #-} TypeRep( Type, Kind ) import {-# SOURCE #-} TcType( TcTyVarDetails, pprTcTyVarDetails ) import {-# SOURCE #-} IdInfo( GlobalIdDetails, notGlobalId, - IdInfo, seqIdInfo ) + IdInfo ) import {-# SOURCE #-} TypeRep( isCoercionKind ) import Name hiding (varName) import Unique import FastTypes import FastString -import Outputable +import Outputable \end{code} @@ -63,13 +102,15 @@ strictness). The essential info about different kinds of @Vars@ is in its @VarDetails@. \begin{code} +-- | Essentially a typed 'Name', that may also contain some additional information +-- about the 'Var' and it's use sites. data Var = TyVar { varName :: !Name, realUnique :: FastInt, -- Key for fast comparison -- Identical to the Unique in the name, -- cached here for speed - varType :: Kind, + varType :: Kind, -- ^ The type or kind of the 'Var' in question isCoercionVar :: Bool } @@ -98,10 +139,8 @@ data Var lclDetails :: LocalIdDetails } data LocalIdDetails - = NotExported -- Not exported - | Exported -- Exported - -- Exported Ids are kept alive; - -- NotExported things may be discarded as dead code. + = NotExported -- ^ Not exported: may be discarded as dead code. + | Exported -- ^ Exported: kept alive \end{code} Note [GlobalId/LocalId] @@ -120,7 +159,6 @@ A LocalId is * always treated as a candidate by the free-variable finder After CoreTidy, top-level LocalIds are turned into GlobalIds - \begin{code} instance Outputable Var where @@ -166,6 +204,36 @@ setVarName :: Var -> Name -> Var setVarName var new_name = var { realUnique = getKeyFastInt (getUnique new_name), varName = new_name } + +setVarType :: Id -> Type -> Id +setVarType id ty = id { varType = ty } + +setIdVarExported :: Var -> Var +-- ^ Exports the given local 'Id'. Can also be called on global 'Id's, such as data constructors +-- and class operations, which are born as global 'Id's and automatically exported +setIdVarExported id@(LocalId {}) = id { lclDetails = Exported } +setIdVarExported other_id = ASSERT( isIdVar other_id ) other_id + +setIdVarNotExported :: Id -> Id +-- ^ We can only do this to LocalIds +setIdVarNotExported id = ASSERT( isLocalIdVar id ) id { lclDetails = NotExported } + +globaliseIdVar :: GlobalIdDetails -> Var -> Var +-- ^ If it's a local, make it global +globaliseIdVar details id = GlobalId { varName = varName id, + realUnique = realUnique id, + varType = varType id, + idInfo_ = varIdInfo id, + gblDetails = details } + +-- | Extract 'Id' information from the 'Var' if it represents a global or local 'Id', otherwise panic +varIdInfo :: Var -> IdInfo +varIdInfo (GlobalId {idInfo_ = info}) = info +varIdInfo (LocalId {idInfo_ = info}) = info +varIdInfo other_var = pprPanic "idInfo" (ppr other_var) + +lazySetVarIdInfo :: Var -> IdInfo -> Var +lazySetVarIdInfo id info = id { idInfo_ = info } \end{code} @@ -205,8 +273,7 @@ mkTyVar name kind = ASSERT( not (isCoercionKind kind ) ) mkTcTyVar :: Name -> Kind -> TcTyVarDetails -> TyVar mkTcTyVar name kind details - = -- TOM: no longer valid assertion? - -- ASSERT( not (isCoercionKind kind) ) + = -- NB: 'kind' may be a coercion kind; cf, 'TcMType.newMetaCoVar' TcTyVar { varName = name, realUnique = getKeyFastInt (nameUnique name), varType = kind, @@ -221,8 +288,9 @@ mkTcTyVar name kind details %************************************************************************ \begin{code} -type CoVar = Var -- A coercion variable is simply a type - -- variable of kind (ty1 :=: ty2) +type CoVar = Var -- A coercion variable is simply a type + -- variable of kind @ty1 :=: ty2@. Hence its + -- 'varType' is always @PredTy (EqPred t1 t2)@ coVarName :: CoVar -> Name coVarName = varName @@ -237,14 +305,12 @@ mkCoVar :: Name -> Kind -> CoVar mkCoVar name kind = ASSERT( isCoercionKind kind ) TyVar { varName = name , realUnique = getKeyFastInt (nameUnique name) - , varType = kind - -- varType is always PredTy (EqPred t1 t2) + , varType = kind , isCoercionVar = True } mkWildCoVar :: Kind -> TyVar --- A type variable that is never referred to, --- so its unique doesn't matter +-- ^ Create a type variable that is never referred to, so its unique doesn't matter mkWildCoVar kind = ASSERT( isCoercionKind kind ) TyVar { varName = mkSysTvName wild_uniq (fsLit "co_wild"), @@ -253,164 +319,113 @@ mkWildCoVar kind isCoercionVar = True } where wild_uniq = mkBuiltinUnique 1 + \end{code} %************************************************************************ %* * -\subsection{Id Construction} +\subsection{Ids} %* * %************************************************************************ -Most Id-related functions are in Id.lhs and MkId.lhs - \begin{code} -type Id = Var -type DictId = Id -\end{code} -\begin{code} -idName :: Id -> Name -idUnique :: Id -> Unique -idType :: Id -> Kind +-- These synonyms are here and not in Id because otherwise we need a very +-- large number of SOURCE imports of Id.hs :-( +type Id = Var +type DictId = Var -idName = varName -idUnique = varUnique -idType = varType - -setIdUnique :: Id -> Unique -> Id -setIdUnique = setVarUnique - -setIdName :: Id -> Name -> Id -setIdName = setVarName - -setIdType :: Id -> Type -> Id -setIdType id ty = id {varType = ty} - -setIdExported :: Id -> Id --- Can be called on GlobalIds, such as data cons and class ops, --- which are "born" as GlobalIds and automatically exported -setIdExported id@(LocalId {}) = id { lclDetails = Exported } -setIdExported other_id = ASSERT( isId other_id ) other_id - -setIdNotExported :: Id -> Id --- We can only do this to LocalIds -setIdNotExported id = ASSERT( isLocalId id ) id { lclDetails = NotExported } - -globaliseId :: GlobalIdDetails -> Id -> Id --- If it's a local, make it global -globaliseId details id = GlobalId { varName = varName id, - realUnique = realUnique id, - varType = varType id, - idInfo_ = idInfo id, - gblDetails = details } - -idInfo :: Id -> IdInfo -idInfo (GlobalId {idInfo_ = info}) = info -idInfo (LocalId {idInfo_ = info}) = info -idInfo other_var = pprPanic "idInfo" (ppr other_var) - -lazySetIdInfo :: Id -> IdInfo -> Id -lazySetIdInfo id info = id {idInfo_ = info} - -setIdInfo :: Id -> IdInfo -> Id -setIdInfo id info = seqIdInfo info `seq` id {idInfo_ = info} - -- Try to avoid spack leaks by seq'ing - -modifyIdInfo :: (IdInfo -> IdInfo) -> Id -> Id -modifyIdInfo fn id - = seqIdInfo new_info `seq` id {idInfo_ = new_info} - where - new_info = fn (idInfo id) - --- maybeModifyIdInfo tries to avoid unnecesary thrashing -maybeModifyIdInfo :: Maybe IdInfo -> Id -> Id -maybeModifyIdInfo (Just new_info) id = id {idInfo_ = new_info} -maybeModifyIdInfo Nothing id = id \end{code} %************************************************************************ %* * -\subsection{Predicates over variables +\subsection{Predicates over variables} %* * %************************************************************************ \begin{code} -mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id -mkGlobalId details name ty info +-- | For an explanation of global vs. local 'Var's, see "Var#globalvslocal" +mkGlobalIdVar :: GlobalIdDetails -> Name -> Type -> IdInfo -> Var +mkGlobalIdVar details name ty info = GlobalId { varName = name, realUnique = getKeyFastInt (nameUnique name), -- Cache the unique varType = ty, gblDetails = details, idInfo_ = info } -mk_local_id :: Name -> Type -> LocalIdDetails -> IdInfo -> Id -mk_local_id name ty details info +mkLocalIdVar' :: Name -> Type -> LocalIdDetails -> IdInfo -> Var +mkLocalIdVar' name ty details info = LocalId { varName = name, realUnique = getKeyFastInt (nameUnique name), -- Cache the unique varType = ty, lclDetails = details, idInfo_ = info } -mkLocalId :: Name -> Type -> IdInfo -> Id -mkLocalId name ty info = mk_local_id name ty NotExported info +-- | For an explanation of global vs. local 'Var's, see "Var#globalvslocal" +mkLocalIdVar :: Name -> Type -> IdInfo -> Var +mkLocalIdVar name ty info = mkLocalIdVar' name ty NotExported info -mkExportedLocalId :: Name -> Type -> IdInfo -> Id -mkExportedLocalId name ty info = mk_local_id name ty Exported info +-- | Exported 'Var's will not be removed as dead code +mkExportedLocalIdVar :: Name -> Type -> IdInfo -> Var +mkExportedLocalIdVar name ty info = mkLocalIdVar' name ty Exported info \end{code} \begin{code} -isTyVar, isTcTyVar :: Var -> Bool -isId, isLocalVar, isLocalId :: Var -> Bool -isGlobalId, isExportedId :: Var -> Bool -mustHaveLocalBinding :: Var -> Bool -isCoVar :: Var -> Bool - +isTyVar :: Var -> Bool isTyVar (TyVar {}) = True isTyVar (TcTyVar {}) = True isTyVar _ = False +isTcTyVar :: Var -> Bool isTcTyVar (TcTyVar {}) = True isTcTyVar _ = False -isId (LocalId {}) = True -isId (GlobalId {}) = True -isId _ = False +isIdVar :: Var -> Bool +isIdVar (LocalId {}) = True +isIdVar (GlobalId {}) = True +isIdVar _ = False -isLocalId (LocalId {}) = True -isLocalId _ = False +isLocalIdVar :: Var -> Bool +isLocalIdVar (LocalId {}) = True +isLocalIdVar _ = False -isCoVar (v@(TyVar {})) = isCoercionVar v -isCoVar _ = False +isCoVar :: Var -> Bool +isCoVar (v@(TyVar {})) = isCoercionVar v +isCoVar (TcTyVar {varType = kind}) = isCoercionKind kind -- used during solving +isCoVar _ = False --- isLocalVar returns True for type variables as well as local Ids +-- | 'isLocalVar' returns @True@ for type variables as well as local 'Id's -- These are the variables that we need to pay attention to when finding free -- variables, or doing dependency analysis. +isLocalVar :: Var -> Bool isLocalVar (GlobalId {}) = False isLocalVar _ = True --- mustHaveLocalBinding returns True of Ids and TyVars +-- | 'mustHaveLocalBinding' returns @True@ of 'Id's and 'TyVar's -- that must have a binding in this module. The converse --- is not quite right: there are some GlobalIds that must have +-- is not quite right: there are some global 'Id's that must have -- bindings, such as record selectors. But that doesn't matter, -- because it's only used for assertions +mustHaveLocalBinding :: Var -> Bool mustHaveLocalBinding var = isLocalVar var -isGlobalId (GlobalId {}) = True -isGlobalId _ = False +isGlobalIdVar :: Var -> Bool +isGlobalIdVar (GlobalId {}) = True +isGlobalIdVar _ = False --- isExportedId means "don't throw this away" -isExportedId (GlobalId {}) = True -isExportedId (LocalId {lclDetails = details}) +-- | 'isExportedIdVar' means \"don't throw this away\" +isExportedIdVar :: Var -> Bool +isExportedIdVar (GlobalId {}) = True +isExportedIdVar (LocalId {lclDetails = details}) = case details of Exported -> True _ -> False -isExportedId _ = False +isExportedIdVar _ = False \end{code} \begin{code} -globalIdDetails :: Var -> GlobalIdDetails --- Works OK on local Ids too, returning notGlobalId -globalIdDetails (GlobalId {gblDetails = details}) = details -globalIdDetails _ = notGlobalId +globalIdVarDetails :: Var -> GlobalIdDetails +-- ^ Find the global 'Id' information if the 'Var' is a global 'Id', otherwise returns 'notGlobalId' +globalIdVarDetails (GlobalId {gblDetails = details}) = details +globalIdVarDetails _ = notGlobalId \end{code} -