\begin{code}
module Var (
- Var, IdOrTyVar, VarDetails, -- Abstract
- varName, varUnique, varInfo, varType,
- setVarName, setVarUnique, setVarType, setVarOcc,
-
+ Var,
+ varName, varUnique,
+ setVarName, setVarUnique,
-- TyVars
- TyVar,
+ TyVar, mkTyVar, mkTcTyVar,
tyVarName, tyVarKind,
setTyVarName, setTyVarUnique,
- mkTyVar, mkSysTyVar, isTyVar, isSigTyVar,
- newMutTyVar, newSigTyVar,
- readMutTyVar, writeMutTyVar, isMutTyVar, makeTyVarImmutable,
-
- -- UVars
- UVar,
- isUVar,
- mkUVar,
+ tcTyVarDetails,
-- Ids
Id, DictId,
idName, idType, idUnique, idInfo, modifyIdInfo, maybeModifyIdInfo,
- setIdName, setIdUnique, setIdInfo,
- mkIdVar, isId, externallyVisibleId
+ setIdName, setIdUnique, setIdType, setIdInfo, lazySetIdInfo,
+ setIdExported, setIdNotExported,
+
+ globalIdDetails, globaliseId,
+
+ mkLocalId, mkExportedLocalId, mkGlobalId,
+
+ isTyVar, isTcTyVar, isId, isLocalVar, isLocalId,
+ isGlobalId, isExportedId,
+ mustHaveLocalBinding
) where
#include "HsVersions.h"
-import {-# SOURCE #-} Type( Type, Kind )
-import {-# SOURCE #-} IdInfo( IdInfo )
+import {-# SOURCE #-} TypeRep( Type )
+import {-# SOURCE #-} TcType( TcTyVarDetails, pprTcTyVarDetails )
+import {-# SOURCE #-} IdInfo( GlobalIdDetails, notGlobalId, IdInfo, seqIdInfo )
-import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey )
-import Name ( Name, OccName, NamedThing(..),
- setNameUnique, setNameOcc, nameUnique,
- mkSysLocalName, isExternallyVisibleName
+import Name ( Name, NamedThing(..),
+ setNameUnique, nameUnique
)
-import BasicTypes ( Unused )
+import Kind ( Kind )
+import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey# )
+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
+ = TyVar {
+ varName :: !Name,
+ realUnique :: FastInt, -- Key for fast comparison
-- Identical to the Unique in the name,
-- cached here for speed
- varType :: Type,
- varDetails :: VarDetails,
- varInfo :: IdInfo -- Only used for Ids at the moment
- }
-
-data VarDetails
- = 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.
--- After type checking there are no MutTyVars left, but there's no static check
--- of that fact.
+ tyVarKind :: Kind }
+
+ | TcTyVar { -- Used only during type inference
+ varName :: !Name,
+ realUnique :: FastInt,
+ tyVarKind :: Kind,
+ tcTyVarDetails :: TcTyVarDetails }
+
+ | GlobalId { -- Used for imported Ids, dict selectors etc
+ varName :: !Name,
+ realUnique :: FastInt,
+ idType :: Type,
+ idInfo :: IdInfo,
+ gblDetails :: GlobalIdDetails }
+
+ | LocalId { -- Used for locally-defined Ids (see NOTE below)
+ varName :: !Name,
+ realUnique :: FastInt,
+ idType :: Type,
+ idInfo :: IdInfo,
+ lclDetails :: LocalIdDetails }
+
+data LocalIdDetails
+ = NotExported -- Not exported
+ | Exported -- Exported
+ -- Exported Ids are kept alive;
+ -- NotExported things may be discarded as dead code.
\end{code}
+LocalId and GlobalId
+~~~~~~~~~~~~~~~~~~~~
+A GlobalId is
+ * always a constant (top-level)
+ * imported, or data constructor, or primop, or record selector
+ * has a Unique that is globally unique across the whole
+ GHC invocation (a single invocation may compile multiple modules)
+
+A LocalId is
+ * bound within an expression (lambda, case, local let(rec))
+ * or defined at top level in the module being compiled
+
+After CoreTidy, top-level LocalIds are turned into GlobalIds
+
+
\begin{code}
instance Outputable Var where
- ppr var = ppr (varName var)
+ ppr var = ppr (varName var) <+> ifPprDebug (brackets extra)
+ where
+ extra = case var of
+ GlobalId {} -> ptext SLIT("gid")
+ LocalId {} -> ptext SLIT("lid")
+ TyVar {} -> ptext SLIT("tv")
+ TcTyVar {tcTyVarDetails = details} -> pprTcTyVarDetails details
instance Show Var where
showsPrec p var = showsPrecSDoc p (ppr var)
\begin{code}
varUnique :: Var -> Unique
-varUnique (Var {realUnique = uniq}) = mkUniqueGrimily uniq
+varUnique var = mkUniqueGrimily (iBox (realUnique var))
setVarUnique :: Var -> Unique -> Var
-setVarUnique var uniq = var {realUnique = getKey uniq,
- varName = setNameUnique (varName var) uniq}
+setVarUnique var uniq
+ = var { realUnique = getKey# uniq,
+ varName = setNameUnique (varName var) uniq }
setVarName :: Var -> Name -> Var
setVarName var new_name
- = var { realUnique = getKey (getUnique new_name), varName = new_name }
-
-setVarOcc :: Var -> OccName -> Var
-setVarOcc var new_occ
- = var { varName = setNameOcc (varName var) new_occ }
-
-setVarType :: Var -> Type -> Var
-setVarType var ty = var {varType = ty}
+ = var { realUnique = getKey# (getUnique new_name),
+ varName = new_name }
\end{code}
\begin{code}
type TyVar = Var
-\end{code}
-\begin{code}
tyVarName = varName
-tyVarKind = varType
setTyVarUnique = setVarUnique
setTyVarName = setVarName
\begin{code}
mkTyVar :: Name -> Kind -> TyVar
-mkTyVar name kind = Var { varName = name
- , realUnique = getKey (nameUnique name)
- , varType = kind
- , varDetails = TyVar
-#ifdef DEBUG
- , varInfo = pprPanic "looking at IdInfo of a tyvar" (ppr name)
-#endif
+mkTyVar name kind = TyVar { varName = name
+ , realUnique = getKey# (nameUnique name)
+ , tyVarKind = kind
}
-mkSysTyVar :: Unique -> Kind -> TyVar
-mkSysTyVar uniq kind = Var { varName = name
- , realUnique = getKey uniq
- , varType = kind
- , varDetails = TyVar
-#ifdef DEBUG
- , varInfo = pprPanic "mkSysTyVar" (ppr name)
-#endif
- }
- 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})
-
-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})
-
-readMutTyVar :: TyVar -> IO (Maybe Type)
-readMutTyVar (Var {varDetails = MutTyVar loc _}) = readIORef loc
-
-writeMutTyVar :: TyVar -> Maybe Type -> IO ()
-writeMutTyVar (Var {varDetails = MutTyVar loc _}) val = writeIORef loc val
-
-makeTyVarImmutable :: TyVar -> TyVar
-makeTyVarImmutable tyvar = tyvar { varDetails = TyVar}
-
-isTyVar :: Var -> Bool
-isTyVar (Var {varDetails = details}) = case details of
- TyVar -> True
- MutTyVar _ _ -> True
- other -> False
-
-isMutTyVar :: Var -> Bool
-isMutTyVar (Var {varDetails = MutTyVar _ _}) = True
-isMutTyVar other = False
-
-isSigTyVar :: Var -> Bool
-isSigTyVar (Var {varDetails = MutTyVar _ is_sig}) = is_sig
-isSigTyVar other = False
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Usage variables}
-%* *
-%************************************************************************
-
-\begin{code}
-type UVar = Var
-\end{code}
-
-\begin{code}
-mkUVar :: Unique -> UVar
-mkUVar unique = Var { varName = mkSysLocalName unique SLIT("u"),
- realUnique = getKey unique,
- varDetails = UVar }
-\end{code}
-
-\begin{code}
-isUVar :: Var -> Bool
-isUVar (Var {varDetails = details}) = case details of
- UVar -> True
- other -> False
+mkTcTyVar :: Name -> Kind -> TcTyVarDetails -> TyVar
+mkTcTyVar name kind details
+ = TcTyVar { varName = name,
+ realUnique = getKey# (nameUnique name),
+ tyVarKind = kind,
+ tcTyVarDetails = details
+ }
\end{code}
\begin{code}
idName = varName
-idType = varType
idUnique = varUnique
-idInfo = varInfo
setIdUnique :: Id -> Unique -> Id
setIdUnique = setVarUnique
setIdName :: Id -> Name -> Id
setIdName = setVarName
+setIdType :: Id -> Type -> Id
+setIdType id ty = id {idType = 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,
+ idType = idType id,
+ idInfo = idInfo id,
+ gblDetails = details }
+
+lazySetIdInfo :: Id -> IdInfo -> Id
+lazySetIdInfo id info = id {idInfo = info}
+
setIdInfo :: Id -> IdInfo -> Id
-setIdInfo var info = var {varInfo = info}
+setIdInfo id info = seqIdInfo info `seq` id {idInfo = info}
+ -- Try to avoid spack leaks by seq'ing
modifyIdInfo :: (IdInfo -> IdInfo) -> Id -> Id
-modifyIdInfo fn var@(Var {varInfo = info}) = var {varInfo = fn info}
+modifyIdInfo fn id
+ = seqIdInfo new_info `seq` id {idInfo = new_info}
+ where
+ new_info = fn (idInfo id)
-- 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}
+maybeModifyIdInfo fn id
+ = case fn (idInfo id) of
+ Nothing -> id
+ Just new_info -> id {idInfo = new_info}
\end{code}
+%************************************************************************
+%* *
+\subsection{Predicates over variables
+%* *
+%************************************************************************
+
\begin{code}
-mkIdVar :: Name -> Type -> IdInfo -> Id
-mkIdVar name ty info
- = Var {varName = name, realUnique = getKey (nameUnique name), varType = ty,
- varDetails = AnId, varInfo = info}
+mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
+mkGlobalId details name ty info
+ = GlobalId { varName = name,
+ realUnique = getKey# (nameUnique name), -- Cache the unique
+ idType = ty,
+ gblDetails = details,
+ idInfo = info }
+
+mk_local_id :: Name -> Type -> LocalIdDetails -> IdInfo -> Id
+mk_local_id name ty details info
+ = LocalId { varName = name,
+ realUnique = getKey# (nameUnique name), -- Cache the unique
+ idType = ty,
+ lclDetails = details,
+ idInfo = info }
+
+mkLocalId :: Name -> Type -> IdInfo -> Id
+mkLocalId name ty info = mk_local_id name ty NotExported info
+
+mkExportedLocalId :: Name -> Type -> IdInfo -> Id
+mkExportedLocalId name ty info = mk_local_id name ty Exported info
\end{code}
\begin{code}
-isId :: Var -> Bool
-isId (Var {varDetails = AnId}) = True
-isId other = False
+isTyVar, isTcTyVar :: Var -> Bool
+isId, isLocalVar, isLocalId :: Var -> Bool
+isGlobalId, isExportedId :: Var -> Bool
+mustHaveLocalBinding :: Var -> Bool
+
+isTyVar (TyVar {}) = True
+isTyVar (TcTyVar {}) = True
+isTyVar other = False
+
+isTcTyVar (TcTyVar {}) = True
+isTcTyVar other = False
+
+isId (LocalId {}) = True
+isId (GlobalId {}) = True
+isId other = False
+
+isLocalId (LocalId {}) = True
+isLocalId other = False
+
+-- isLocalVar returns True for type variables as well as local Ids
+-- These are the variables that we need to pay attention to when finding free
+-- variables, or doing dependency analysis.
+isLocalVar (GlobalId {}) = False
+isLocalVar other = True
+
+-- mustHaveLocalBinding returns True of Ids and TyVars
+-- that must have a binding in this module. The converse
+-- is not quite right: there are some GlobalIds that must have
+-- bindings, such as record selectors. But that doesn't matter,
+-- because it's only used for assertions
+mustHaveLocalBinding var = isLocalVar var
+
+isGlobalId (GlobalId {}) = True
+isGlobalId other = False
+
+-- isExportedId means "don't throw this away"
+isExportedId (GlobalId {}) = True
+isExportedId (LocalId {lclDetails = details})
+ = case details of
+ Exported -> True
+ other -> False
+isExportedId other = False
\end{code}
-@externallyVisibleId@: is it true that another module might be
-able to ``see'' this Id in a code generation sense. That
-is, another .o file might refer to this Id.
-
-In tidyCorePgm (SimplCore.lhs) we carefully set each top level thing's
-local-ness precisely so that the test here would be easy
-
-This defn appears here (rather than, say, in Id.lhs) because
-CostCentre.lhs uses it (CostCentre feeds PprType feeds Id.lhs)
-
-\end{code}
\begin{code}
-externallyVisibleId :: Id -> Bool
-externallyVisibleId var = isExternallyVisibleName (varName var)
+globalIdDetails :: Var -> GlobalIdDetails
+-- Works OK on local Ids too, returning notGlobalId
+globalIdDetails (GlobalId {gblDetails = details}) = details
+globalIdDetails other = notGlobalId
\end{code}
+
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