X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FbasicTypes%2FVar.lhs;h=66876c6415deb6c03dd4c782953e7b6eb34d0625;hb=fc6b00498e653d6260e062bdfccbeede0a20fadd;hp=47d84a394886044d00ccc6de934f3fde0c6982ce;hpb=991a868b891c98cd58baf59cab423355a6b7025e;p=ghc-hetmet.git

diff --git a/ghc/compiler/basicTypes/Var.lhs b/ghc/compiler/basicTypes/Var.lhs
index 47d84a3..66876c6 100644
--- a/ghc/compiler/basicTypes/Var.lhs
+++ b/ghc/compiler/basicTypes/Var.lhs
@@ -14,8 +14,7 @@ module Var (
 	tyVarName, tyVarKind,
 	setTyVarName, setTyVarUnique,
 	mkTyVar, mkSysTyVar, 
-	newMutTyVar, newSigTyVar,
-	readMutTyVar, writeMutTyVar, makeTyVarImmutable,
+	mkMutTyVar, mutTyVarRef, makeTyVarImmutable, 
 
 	-- Ids
 	Id, DictId,
@@ -27,7 +26,7 @@ module Var (
 
 	mkLocalId, mkGlobalId, mkSpecPragmaId,
 
-	isTyVar, isMutTyVar, isSigTyVar,
+	isTyVar, isMutTyVar, mutTyVarDetails,
 	isId, isLocalVar, isLocalId,
 	isGlobalId, isExportedId, isSpecPragmaId,
 	mustHaveLocalBinding
@@ -36,18 +35,19 @@ module Var (
 #include "HsVersions.h"
 
 import {-# SOURCE #-}	TypeRep( Type, Kind )
+import {-# SOURCE #-}	TcType( TyVarDetails )
 import {-# SOURCE #-}	IdInfo( GlobalIdDetails, notGlobalId,
 				IdInfo, seqIdInfo )
 
 import Name		( Name, OccName, NamedThing(..),
 			  setNameUnique, setNameOcc, nameUnique, 
-			  mkSysLocalName
+			  mkSystemTvNameEncoded,
 			)
 import Unique		( Unique, Uniquable(..), mkUniqueGrimily, getKey )
 import FastTypes
 import Outputable
 
-import IOExts		( IORef, newIORef, readIORef, writeIORef )
+import DATA_IOREF	( IORef )
 \end{code}
 
 
@@ -66,7 +66,7 @@ in its @VarDetails@.
 \begin{code}
 data Var
   = Var {
-	varName    :: Name,
+	varName    :: !Name,
 	realUnique :: FastInt,		-- Key for fast comparison
 					-- Identical to the Unique in the name,
 					-- cached here for speed
@@ -84,13 +84,15 @@ data VarDetails
 
   | 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
+	     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.
+	-- 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
@@ -196,35 +198,25 @@ mkSysTyVar uniq kind = Var { varName    = name
 			   , varInfo    = pprPanic "mkSysTyVar" (ppr name)
 			   }
 		     where
-		       name = mkSysLocalName uniq SLIT("t")
+		       name = mkSystemTvNameEncoded uniq FSLIT("t")
 
-newMutTyVar :: Name -> Kind -> IO TyVar
-newMutTyVar name kind = newTyVar name kind False
+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)
+	}
 
-newSigTyVar :: Name -> Kind -> IO TyVar
--- 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
-
-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}
+
+mutTyVarDetails :: TyVar -> TyVarDetails
+mutTyVarDetails (Var {varDetails = MutTyVar _ details}) = details
 \end{code}
 
 
@@ -308,7 +300,7 @@ mkGlobalId details name ty info = mkId name ty (GlobalId details) info
 \end{code}
 
 \begin{code}
-isTyVar, isMutTyVar, isSigTyVar		 :: Var -> Bool
+isTyVar, isMutTyVar			 :: Var -> Bool
 isId, isLocalVar, isLocalId    		 :: Var -> Bool
 isGlobalId, isExportedId, isSpecPragmaId :: Var -> Bool
 mustHaveLocalBinding			 :: Var -> Bool
@@ -321,8 +313,6 @@ isTyVar var = case varDetails var of
 isMutTyVar (Var {varDetails = MutTyVar _ _}) = True
 isMutTyVar other			     = False
 
-isSigTyVar (Var {varDetails = MutTyVar _ is_sig}) = is_sig
-isSigTyVar other			          = False
 
 isId var = case varDetails var of
 		LocalId _  -> True