-
+%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section{@Vars@: Variables}
\begin{code}
module Var (
- Var, IdOrTyVar, -- Abstract
- VarDetails(..), -- Concrete
- varName, varUnique, varDetails, varInfo, varType,
- setVarName, setVarUnique, setVarType, setVarOcc,
-
+ Var, VarDetails, -- Abstract
+ varName, varUnique, varInfo, varType,
+ setVarName, setVarUnique, setVarType, setVarOcc,
-- TyVars
TyVar,
newMutTyVar, newSigTyVar,
readMutTyVar, writeMutTyVar, isMutTyVar, makeTyVarImmutable,
+ -- UVars
+ UVar,
+ isUVar,
+ mkUVar, mkNamedUVar,
+
-- Ids
Id, DictId,
- idDetails, idName, idType, idUnique, idInfo, modifyIdInfo,
- setIdName, setIdUnique, setIdInfo,
- mkId, isId, externallyVisibleId
+ idName, idType, idUnique, idInfo, modifyIdInfo, maybeModifyIdInfo,
+ setIdName, setIdUnique, setIdInfo, lazySetIdInfo, zapIdInfo,
+ mkIdVar, isId, externallyVisibleId
) where
#include "HsVersions.h"
-import {-# SOURCE #-} Type( Type, Kind )
-import {-# SOURCE #-} IdInfo( IdInfo )
-import {-# SOURCE #-} Const( Con )
+import {-# SOURCE #-} TypeRep( Type, Kind )
+import {-# SOURCE #-} IdInfo( IdInfo, seqIdInfo, vanillaIdInfo )
-import FieldLabel ( FieldLabel )
import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey )
import Name ( Name, OccName, NamedThing(..),
setNameUnique, setNameOcc, nameUnique,
mkSysLocalName, isExternallyVisibleName
)
-import BasicTypes ( Unused )
+import FastTypes
import Outputable
import IOExts ( IORef, newIORef, readIORef, writeIORef )
\end{code}
-
%************************************************************************
%* *
\subsection{The main data type declarations}
in its @VarDetails@.
\begin{code}
-type IdOrTyVar = Var
-
data Var
= Var {
varName :: Name,
- realUnique :: Int#, -- Key for fast comparison
+ realUnique :: FastInt, -- Key for fast comparison
-- Identical to the Unique in the name,
-- cached here for speed
varType :: Type,
}
data VarDetails
- = VanillaId -- Most Ids are like this
- | ConstantId Con -- The Id for a constant (data constructor or primop)
- | RecordSelId FieldLabel -- The Id for a record selector
+ = AnId
| TyVar
| MutTyVar (IORef (Maybe Type)) -- Used during unification;
Bool -- True <=> this is a type signature variable, which
-- should not be unified with a non-tyvar type
+ | UVar -- Usage variable
-- For a long time I tried to keep mutable Vars statically type-distinct
-- from immutable Vars, but I've finally given up. It's just too painful.
varUnique (Var {realUnique = uniq}) = mkUniqueGrimily uniq
setVarUnique :: Var -> Unique -> Var
-setVarUnique var uniq = var {realUnique = getKey uniq,
- varName = setNameUnique (varName var) uniq}
+setVarUnique var@(Var {varName = name}) uniq
+ = var {realUnique = getKey uniq,
+ varName = setNameUnique name uniq}
setVarName :: Var -> Name -> Var
setVarName var new_name
, realUnique = getKey (nameUnique name)
, varType = kind
, varDetails = TyVar
-#ifdef DEBUG
- , varInfo = pprPanic "mkTyVar" (ppr name)
-#endif
+ , varInfo = pprPanic "mkTyVar" (ppr name)
}
mkSysTyVar :: Unique -> Kind -> TyVar
, realUnique = getKey uniq
, varType = kind
, varDetails = TyVar
-#ifdef DEBUG
- , varInfo = pprPanic "mkSysTyVar" (ppr name)
-#endif
+ , varInfo = pprPanic "mkSysTyVar" (ppr name)
}
where
name = mkSysLocalName uniq SLIT("t")
newMutTyVar :: Name -> Kind -> IO TyVar
-newMutTyVar name kind =
- do loc <- newIORef Nothing
- return (Var { varName = name,
- realUnique = getKey (nameUnique name),
- varType = kind,
- varDetails = MutTyVar loc False})
+newMutTyVar name kind = newTyVar name kind False
newSigTyVar :: Name -> Kind -> IO TyVar
-newSigTyVar name kind =
- do loc <- newIORef Nothing
- return (Var { varName = name,
- realUnique = getKey (nameUnique name),
- varType = kind,
- varDetails = MutTyVar loc True})
+-- Type variables from type signatures are still mutable, because
+-- they may get unified with type variables from other signatures
+-- But they do contain a flag to distinguish them, so we can tell if
+-- we unify them with a non-type-variable.
+newSigTyVar name kind = newTyVar name kind True
+
+newTyVar name kind is_sig
+ = do loc <- newIORef Nothing
+ return (Var { varName = name
+ , realUnique = getKey (nameUnique name)
+ , varType = kind
+ , varDetails = MutTyVar loc is_sig
+ , varInfo = pprPanic "newMutTyVar" (ppr name)
+ })
readMutTyVar :: TyVar -> IO (Maybe Type)
readMutTyVar (Var {varDetails = MutTyVar loc _}) = readIORef loc
makeTyVarImmutable :: TyVar -> TyVar
makeTyVarImmutable tyvar = tyvar { varDetails = TyVar}
-\end{code}
-\begin{code}
isTyVar :: Var -> Bool
isTyVar (Var {varDetails = details}) = case details of
TyVar -> True
%************************************************************************
%* *
+\subsection{Usage variables}
+%* *
+%************************************************************************
+
+\begin{code}
+type UVar = Var
+\end{code}
+
+\begin{code}
+mkUVar :: Unique -> UVar
+mkUVar unique = Var { varName = name
+ , realUnique = getKey unique
+ , varDetails = UVar
+ , varType = pprPanic "mkUVar (varType)" (ppr name)
+ , varInfo = pprPanic "mkUVar (varInfo)" (ppr name)
+ }
+ where name = mkSysLocalName unique SLIT("u")
+
+mkNamedUVar :: Name -> UVar
+mkNamedUVar name = Var { varName = name
+ , realUnique = getKey (nameUnique name)
+ , varDetails = UVar
+ , varType = pprPanic "mkNamedUVar (varType)" (ppr name)
+ , varInfo = pprPanic "mkNamedUVar (varInfo)" (ppr name)
+ }
+\end{code}
+
+\begin{code}
+isUVar :: Var -> Bool
+isUVar (Var {varDetails = details}) = case details of
+ UVar -> True
+ other -> False
+\end{code}
+
+
+%************************************************************************
+%* *
\subsection{Id Construction}
%* *
%************************************************************************
- Most Id-related functions are in Id.lhs and MkId.lhs
+Most Id-related functions are in Id.lhs and MkId.lhs
\begin{code}
type Id = Var
idType = varType
idUnique = varUnique
idInfo = varInfo
-idDetails = varDetails
setIdUnique :: Id -> Unique -> Id
setIdUnique = setVarUnique
setIdName :: Id -> Name -> Id
setIdName = setVarName
-setIdInfo :: Id -> IdInfo -> Id
-setIdInfo var info = var {varInfo = info}
+lazySetIdInfo :: Id -> IdInfo -> Id
+lazySetIdInfo var info = var {varInfo = info}
-modifyIdInfo :: Id -> (IdInfo -> IdInfo) -> Id
-modifyIdInfo var@(Var {varInfo = info}) fn = var {varInfo = fn info}
+setIdInfo :: Id -> IdInfo -> Id
+setIdInfo var info = seqIdInfo info `seq` var {varInfo = info}
+ -- Try to avoid spack leaks by seq'ing
+
+zapIdInfo :: Id -> Id
+zapIdInfo var = var {varInfo = vanillaIdInfo}
+
+modifyIdInfo :: (IdInfo -> IdInfo) -> Id -> Id
+modifyIdInfo fn var@(Var {varInfo = info})
+ = seqIdInfo new_info `seq` var {varInfo = new_info}
+ where
+ new_info = fn info
+
+-- maybeModifyIdInfo tries to avoid unnecesary thrashing
+maybeModifyIdInfo :: (IdInfo -> Maybe IdInfo) -> Id -> Id
+maybeModifyIdInfo fn var@(Var {varInfo = info}) = case fn info of
+ Nothing -> var
+ Just new_info -> var {varInfo = new_info}
\end{code}
\begin{code}
-mkId :: Name -> Type -> VarDetails -> IdInfo -> Id
-mkId name ty details info
+mkIdVar :: Name -> Type -> IdInfo -> Id
+mkIdVar name ty info
= Var {varName = name, realUnique = getKey (nameUnique name), varType = ty,
- varDetails = details, varInfo = info}
+ varDetails = AnId, varInfo = info}
\end{code}
\begin{code}
isId :: Var -> Bool
-isId (Var {varDetails = details}) = case details of
- VanillaId -> True
- ConstantId _ -> True
- RecordSelId _ -> True
- other -> False
+isId (Var {varDetails = AnId}) = True
+isId other = False
\end{code}
@externallyVisibleId@: is it true that another module might be
projects / ghc-hetmet.git / blobdiff