-
+%
% (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,
-
+ Var, VarDetails, -- Abstract
+ varName, varUnique, varInfo, varType,
+ setVarName, setVarUnique, setVarType, setVarOcc,
-- TyVars
- TyVar, GenTyVar,
+ TyVar,
tyVarName, tyVarKind,
- tyVarFlexi, setTyVarFlexi, removeTyVarFlexi, setTyVarName, setTyVarUnique,
- mkFlexiTyVar, mkTyVar, mkSysTyVar, isTyVar, isFlexiTyVar,
+ setTyVarName, setTyVarUnique,
+ mkTyVar, mkSysTyVar,
+ mkMutTyVar, mutTyVarRef, makeTyVarImmutable,
-- Ids
- Id, DictId, GenId,
- idName, idType, idUnique, idInfo, modifyIdInfo,
- setIdName, setIdUnique, setIdInfo,
- mkId, isId, externallyVisibleId
+ Id, DictId,
+ idName, idType, idUnique, idInfo, modifyIdInfo, maybeModifyIdInfo,
+ setIdName, setIdUnique, setIdInfo, lazySetIdInfo,
+ setIdLocalExported, zapSpecPragmaId,
+
+ globalIdDetails, setGlobalIdDetails,
+
+ mkLocalId, mkGlobalId, mkSpecPragmaId,
+
+ isTyVar, isMutTyVar, mutTyVarDetails,
+ isId, isLocalVar, isLocalId,
+ isGlobalId, isExportedId, isSpecPragmaId,
+ mustHaveLocalBinding
) where
#include "HsVersions.h"
-import {-# SOURCE #-} Type( GenType, Kind )
-import {-# SOURCE #-} IdInfo( IdInfo )
-import {-# SOURCE #-} Const( Con )
+import {-# SOURCE #-} TypeRep( Type, Kind )
+import {-# SOURCE #-} TcType( TyVarDetails )
+import {-# SOURCE #-} IdInfo( GlobalIdDetails, notGlobalId,
+ IdInfo, seqIdInfo )
-import FieldLabel ( FieldLabel )
-import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey )
-import Name ( Name, NamedThing(..),
- changeUnique, nameUnique,
- mkSysLocalName, isExternallyVisibleName
+import Name ( Name, OccName, NamedThing(..),
+ setNameUnique, setNameOcc, nameUnique,
+ mkSystemTvNameEncoded,
)
-import BasicTypes ( Unused )
+import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey# )
+import FastTypes
import Outputable
-\end{code}
+import DATA_IOREF ( IORef )
+\end{code}
%************************************************************************
in its @VarDetails@.
\begin{code}
-type IdOrTyVar = Var Unused Unused
-
-data Var flex_self flex_ty
+data Var
= Var {
- varName :: Name,
- realUnique :: Int#, -- Key for fast comparison
+ varName :: !Name,
+ realUnique :: FastInt, -- Key for fast comparison
-- Identical to the Unique in the name,
-- cached here for speed
- varType :: GenType flex_ty,
- varDetails :: VarDetails flex_self,
+ varType :: Type,
+ varDetails :: VarDetails,
varInfo :: IdInfo -- Only used for Ids at the moment
}
-varUnique Var{realUnique = uniq} = mkUniqueGrimily uniq
-
-data VarDetails flex_self
- = TyVar
- | FlexiTyVar flex_self -- Used during unification
- | 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
+data VarDetails
+ = LocalId -- Used for locally-defined Ids (see NOTE below)
+ LocalIdDetails
+
+ | GlobalId -- Used for imported Ids, dict selectors etc
+ GlobalIdDetails
+
+ | TyVar
+ | MutTyVar (IORef (Maybe Type)) -- Used during unification;
+ TyVarDetails
+ -- TODO: the IORef should be unboxed here, but we don't want to unbox
+ -- the Name above.
+
+ -- 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.
+
+data LocalIdDetails
+ = NotExported -- Not exported
+ | Exported -- Exported
+ | SpecPragma -- Not exported, but not to be discarded either
+ -- It's unclean that this is so deeply built in
\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 fs ft) where
+instance Outputable Var where
ppr var = ppr (varName var)
-instance Show (Var fs ft) where
+instance Show Var where
showsPrec p var = showsPrecSDoc p (ppr var)
-instance NamedThing (Var fs ft) where
+instance NamedThing Var where
getName = varName
-instance Uniquable (Var fs ft) where
+instance Uniquable Var where
getUnique = varUnique
-instance Eq (Var fs ft) where
+instance Eq Var where
a == b = realUnique a ==# realUnique b
-instance Ord (Var fs ft) where
+instance Ord Var where
a <= b = realUnique a <=# realUnique b
a < b = realUnique a <# realUnique b
a >= b = realUnique a >=# realUnique b
\begin{code}
-setVarUnique :: Var fs ft -> Unique -> Var fs ft
-setVarUnique var uniq = var {realUnique = getKey uniq,
- varName = changeUnique (varName var) uniq}
+varUnique :: Var -> Unique
+varUnique (Var {realUnique = uniq}) = mkUniqueGrimily (iBox uniq)
-setVarName :: Var fs ft -> Name -> Var fs ft
+setVarUnique :: Var -> Unique -> Var
+setVarUnique var@(Var {varName = name}) uniq
+ = var {realUnique = getKey# uniq,
+ varName = setNameUnique name uniq}
+
+setVarName :: Var -> Name -> Var
setVarName var new_name
- = var { realUnique = getKey (getUnique new_name), varName = 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 flex_self flex_ty1 -> GenType flex_ty2 -> Var flex_self flex_ty2
+setVarType :: Var -> Type -> Var
setVarType var ty = var {varType = ty}
\end{code}
%************************************************************************
\begin{code}
-type GenTyVar flex_self = Var flex_self Unused -- Perhaps a mutable tyvar, but
- -- with a fixed Kind
-
-type TyVar = GenTyVar Unused -- NOt even mutable
+type TyVar = Var
\end{code}
\begin{code}
setTyVarUnique = setVarUnique
setTyVarName = setVarName
-
-tyVarFlexi :: GenTyVar flexi -> flexi
-tyVarFlexi (Var {varDetails = FlexiTyVar flex}) = flex
-tyVarFlexi other_var = pprPanic "tyVarFlexi" (ppr other_var)
-
-setTyVarFlexi :: GenTyVar flexi1 -> flexi2 -> GenTyVar flexi2
-setTyVarFlexi var flex = var {varDetails = FlexiTyVar flex}
-
-removeTyVarFlexi :: GenTyVar flexi1 -> GenTyVar flexi2
-removeTyVarFlexi var = var {varDetails = TyVar}
\end{code}
\begin{code}
-mkTyVar :: Name -> Kind -> GenTyVar flexi
-mkTyVar name kind = Var { varName = name, realUnique = getKey (nameUnique name),
- varType = kind, varDetails = TyVar }
-
-mkSysTyVar :: Unique -> Kind -> GenTyVar flexi
-mkSysTyVar uniq kind = Var { varName = name, realUnique = getKey uniq,
- varType = kind, varDetails = TyVar }
+mkTyVar :: Name -> Kind -> TyVar
+mkTyVar name kind = Var { varName = name
+ , realUnique = getKey# (nameUnique name)
+ , varType = kind
+ , varDetails = TyVar
+ , varInfo = pprPanic "mkTyVar" (ppr name)
+ }
+
+mkSysTyVar :: Unique -> Kind -> TyVar
+mkSysTyVar uniq kind = Var { varName = name
+ , realUnique = getKey# uniq
+ , varType = kind
+ , varDetails = TyVar
+ , varInfo = pprPanic "mkSysTyVar" (ppr name)
+ }
where
- name = mkSysLocalName uniq
+ name = mkSystemTvNameEncoded uniq FSLIT("t")
-mkFlexiTyVar :: Name -> Kind -> flexi -> GenTyVar flexi
-mkFlexiTyVar name kind flex = Var { varName = name,
- realUnique = getKey (nameUnique name),
- varType = kind,
- varDetails = FlexiTyVar flex }
-\end{code}
+mkMutTyVar :: Name -> Kind -> TyVarDetails -> IORef (Maybe Type) -> TyVar
+mkMutTyVar name kind details ref
+ = Var { varName = name
+ , realUnique = getKey# (nameUnique name)
+ , varType = kind
+ , varDetails = MutTyVar ref details
+ , varInfo = pprPanic "newMutTyVar" (ppr name)
+ }
-\begin{code}
-isTyVar :: Var fs ft -> Bool
-isTyVar (Var {varDetails = details}) = case details of
- TyVar -> True
- FlexiTyVar _ -> True
- other -> False
-
-isFlexiTyVar :: Var fs ft -> Bool
-isFlexiTyVar (Var {varDetails = FlexiTyVar _}) = True
-isFlexiTyVar other = False
+mutTyVarRef :: TyVar -> IORef (Maybe Type)
+mutTyVarRef (Var {varDetails = MutTyVar loc _}) = loc
+
+makeTyVarImmutable :: TyVar -> TyVar
+makeTyVarImmutable tyvar = tyvar { varDetails = TyVar}
+
+mutTyVarDetails :: TyVar -> TyVarDetails
+mutTyVarDetails (Var {varDetails = MutTyVar _ details}) = details
\end{code}
%* *
%************************************************************************
- 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 GenId flex_ty = Var Unused flex_ty
-type Id = GenId Unused
-type DictId = Id
+type Id = Var
+type DictId = Id
\end{code}
\begin{code}
idType = varType
idUnique = varUnique
idInfo = varInfo
-idDetails = varDetails
setIdUnique :: Id -> Unique -> Id
setIdUnique = setVarUnique
setIdName :: Id -> Name -> Id
setIdName = setVarName
-setIdInfo :: GenId flexi -> IdInfo -> GenId flexi
-setIdInfo var info = var {varInfo = info}
-
-modifyIdInfo :: GenId flexi -> (IdInfo -> IdInfo) -> GenId flexi
-modifyIdInfo var@(Var {varInfo = info}) fn = var {varInfo = fn info}
+setIdLocalExported :: Id -> Id
+setIdLocalExported id = id { varDetails = LocalId Exported }
+
+zapSpecPragmaId :: Id -> Id
+zapSpecPragmaId id
+ = case varDetails id of
+ LocalId SpecPragma -> id { varDetails = LocalId NotExported }
+ other -> id
+
+lazySetIdInfo :: Id -> IdInfo -> Id
+lazySetIdInfo var info = var {varInfo = info}
+
+setIdInfo :: Id -> IdInfo -> Id
+setIdInfo var info = seqIdInfo info `seq` var {varInfo = info}
+ -- Try to avoid spack leaks by seq'ing
+
+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 -> GenType flex_ty -> VarDetails Unused -> IdInfo -> GenId flex_ty
-mkId name ty details info
- = Var {varName = name, realUnique = getKey (nameUnique name), varType = ty,
- varDetails = details, varInfo = info}
-\end{code}
+%************************************************************************
+%* *
+\subsection{Predicates over variables
+%* *
+%************************************************************************
\begin{code}
-isId :: Var fs ft -> Bool
-isId (Var {varDetails = details}) = case details of
- VanillaId -> True
- ConstantId _ -> True
- RecordSelId _ -> True
- other -> False
-\end{code}
+mkId :: Name -> Type -> VarDetails -> IdInfo -> Id
+mkId name ty details info
+ = Var { varName = name,
+ realUnique = getKey# (nameUnique name), -- Cache the unique
+ varType = ty,
+ varDetails = details,
+ varInfo = info }
-@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.
+mkLocalId :: Name -> Type -> IdInfo -> Id
+mkLocalId name ty info = mkId name ty (LocalId NotExported) info
-In tidyCorePgm (SimplCore.lhs) we carefully set each top level thing's
-local-ness precisely so that the test here would be easy
+mkSpecPragmaId :: Name -> Type -> IdInfo -> Id
+mkSpecPragmaId name ty info = mkId name ty (LocalId SpecPragma) info
-This defn appears here (rather than, say, in Id.lhs) because
-CostCentre.lhs uses it (CostCentre feeds PprType feeds Id.lhs)
+mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
+mkGlobalId details name ty info = mkId name ty (GlobalId details) info
+\end{code}
+\begin{code}
+isTyVar, isMutTyVar :: Var -> Bool
+isId, isLocalVar, isLocalId :: Var -> Bool
+isGlobalId, isExportedId, isSpecPragmaId :: Var -> Bool
+mustHaveLocalBinding :: Var -> Bool
+
+isTyVar var = case varDetails var of
+ TyVar -> True
+ MutTyVar _ _ -> True
+ other -> False
+
+isMutTyVar (Var {varDetails = MutTyVar _ _}) = True
+isMutTyVar other = False
+
+
+isId var = case varDetails var of
+ LocalId _ -> True
+ GlobalId _ -> True
+ other -> False
+
+isLocalId var = case varDetails var of
+ LocalId _ -> True
+ 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 var = case varDetails var of
+ LocalId _ -> True
+ TyVar -> True
+ MutTyVar _ _ -> True
+ other -> False
+
+-- 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 var = case varDetails var of
+ GlobalId _ -> True
+ other -> False
+
+-- isExportedId means "don't throw this away"
+isExportedId var = case varDetails var of
+ LocalId Exported -> True
+ LocalId SpecPragma -> True
+ GlobalId _ -> True
+ other -> False
+
+isSpecPragmaId var = case varDetails var of
+ LocalId SpecPragma -> True
+ other -> False
\end{code}
+
\begin{code}
-externallyVisibleId :: Id -> Bool
-externallyVisibleId var = isExternallyVisibleName (varName var)
+globalIdDetails :: Var -> GlobalIdDetails
+-- Works OK on local Ids too, returning notGlobalId
+globalIdDetails var = case varDetails var of
+ GlobalId details -> details
+ other -> notGlobalId
+setGlobalIdDetails :: Id -> GlobalIdDetails -> Id
+setGlobalIdDetails id details = id { varDetails = GlobalId details }
\end{code}
+