-
+%
% (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,
tyVarName, tyVarKind,
setTyVarName, setTyVarUnique,
- mkTyVar, mkSysTyVar, isTyVar,
- newMutTyVar, readMutTyVar, writeMutTyVar, isMutTyVar, makeTyVarImmutable,
+ mkTyVar, mkSysTyVar,
+ mkMutTyVar, mutTyVarRef, makeTyVarImmutable,
-- 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,
+ setIdLocalExported, zapSpecPragmaId,
+
+ globalIdDetails, setGlobalIdDetails,
+
+ mkLocalId, mkGlobalId, mkSpecPragmaId,
+
+ isTyVar, isMutTyVar, mutTyVarDetails,
+ isId, isLocalVar, isLocalId,
+ isGlobalId, isExportedId, isSpecPragmaId,
+ mustHaveLocalBinding
) where
#include "HsVersions.h"
-import {-# SOURCE #-} Type( Type, 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, OccName, NamedThing(..),
setNameUnique, setNameOcc, nameUnique,
- mkSysLocalName, isExternallyVisibleName
+ mkSystemTvNameEncoded,
)
-import BasicTypes ( Unused )
+import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey# )
+import FastTypes
import Outputable
-import IOExts ( IORef, newIORef, readIORef, writeIORef )
+import DATA_IOREF ( IORef )
\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
+ varName :: !Name,
+ 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
- | TyVar
- | MutTyVar (IORef (Maybe Type)) -- Used during unification
+ = LocalId -- Used for locally-defined Ids (see NOTE below)
+ LocalIdDetails
--- 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.
+ | 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 where
ppr var = ppr (varName var)
\begin{code}
varUnique :: Var -> Unique
-varUnique (Var {realUnique = uniq}) = mkUniqueGrimily uniq
+varUnique (Var {realUnique = uniq}) = mkUniqueGrimily (iBox 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
- = 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
\begin{code}
mkTyVar :: Name -> Kind -> TyVar
mkTyVar name kind = Var { varName = name
- , realUnique = getKey (nameUnique 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
mkSysTyVar uniq kind = Var { varName = name
- , realUnique = getKey uniq
+ , 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 })
+ name = mkSystemTvNameEncoded uniq FSLIT("t")
-readMutTyVar :: TyVar -> IO (Maybe Type)
-readMutTyVar (Var {varDetails = MutTyVar loc}) = readIORef loc
+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)
+ }
-writeMutTyVar :: TyVar -> Maybe Type -> IO ()
-writeMutTyVar (Var {varDetails = MutTyVar loc}) val = writeIORef loc val
+mutTyVarRef :: TyVar -> IORef (Maybe Type)
+mutTyVarRef (Var {varDetails = MutTyVar loc _}) = 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
- MutTyVar _ -> True
- other -> False
-
-isMutTyVar :: Var -> Bool
-isMutTyVar (Var {varDetails = MutTyVar _}) = True
-isMutTyVar other = False
+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 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}
+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}
-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
+
+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}
+%************************************************************************
+%* *
+\subsection{Predicates over variables
+%* *
+%************************************************************************
+
\begin{code}
mkId :: Name -> Type -> VarDetails -> IdInfo -> Id
mkId name ty details info
- = Var {varName = name, realUnique = getKey (nameUnique name), varType = ty,
- varDetails = details, varInfo = info}
-\end{code}
-
-\begin{code}
-isId :: Var -> Bool
-isId (Var {varDetails = details}) = case details of
- VanillaId -> True
- ConstantId _ -> True
- RecordSelId _ -> True
- other -> False
-\end{code}
+ = 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}
+
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