X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FVar.lhs;h=f2bef26ba2d57e77ee6a92555705150239b94c30;hp=60fdf3831c3c5de74a15612b80089db9189cf292;hb=ad94d40948668032189ad22a0ad741ac1f645f50;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1

diff --git a/compiler/basicTypes/Var.lhs b/compiler/basicTypes/Var.lhs
index 60fdf38..f2bef26 100644
--- a/compiler/basicTypes/Var.lhs
+++ b/compiler/basicTypes/Var.lhs
@@ -1,25 +1,36 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
 \section{@Vars@: Variables}
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings
+-- for details
+
 module Var (
 	Var, 
-	varName, varUnique, 
+	varName, varUnique, varType,
 	setVarName, setVarUnique, 
 
 	-- TyVars
-	TyVar, mkTyVar, mkTcTyVar,
+	TyVar, mkTyVar, mkTcTyVar, mkWildCoVar,
 	tyVarName, tyVarKind,
-	setTyVarName, setTyVarUnique,
+	setTyVarName, setTyVarUnique, setTyVarKind,
 	tcTyVarDetails,
 
+        -- CoVars
+        CoVar, coVarName, setCoVarUnique, setCoVarName, mkCoVar, isCoVar,
+
 	-- Ids
 	Id, DictId,
 	idName, idType, idUnique, idInfo, modifyIdInfo, maybeModifyIdInfo,
 	setIdName, setIdUnique, setIdType, setIdInfo, lazySetIdInfo, 
-	setIdExported, setIdNotExported, 
+	setIdExported, setIdNotExported,
 
 	globalIdDetails, globaliseId, 
 
@@ -32,17 +43,19 @@ module Var (
 
 #include "HsVersions.h"
 
-import {-# SOURCE #-}	TypeRep( Type )
+import {-# SOURCE #-}	TypeRep( Type, Kind )
 import {-# SOURCE #-}	TcType( TcTyVarDetails, pprTcTyVarDetails )
-import {-# SOURCE #-}	IdInfo( GlobalIdDetails, notGlobalId, IdInfo, seqIdInfo )
-
-import Name		( Name, NamedThing(..),
-			  setNameUnique, nameUnique
-			)
-import Kind		( Kind )
-import Unique		( Unique, Uniquable(..), mkUniqueGrimily, getKey# )
+import {-# SOURCE #-}	IdInfo( GlobalIdDetails, notGlobalId, 
+                                IdInfo, seqIdInfo )
+#ifdef DEBUG
+import {-# SOURCE #-}	TypeRep( isCoercionKind )
+#endif
+
+import Name hiding (varName)
+import Unique
 import FastTypes
-import Outputable
+import FastString
+import Outputable       
 \end{code}
 
 
@@ -65,26 +78,32 @@ data Var
 	realUnique :: FastInt,		-- Key for fast comparison
 					-- Identical to the Unique in the name,
 					-- cached here for speed
-	tyVarKind :: Kind }
+	varType       :: Kind,
+        isCoercionVar :: Bool
+ }
 
   | TcTyVar { 				-- Used only during type inference
+					-- Used for kind variables during 
+					-- inference, as well
 	varName        :: !Name,
 	realUnique     :: FastInt,
-	tyVarKind      :: Kind,
+	varType        :: Kind,
 	tcTyVarDetails :: TcTyVarDetails }
 
   | GlobalId { 			-- Used for imported Ids, dict selectors etc
-	varName    :: !Name,
+ 				-- See Note [GlobalId/LocalId] below
+	varName    :: !Name,	-- Always an External or WiredIn Name
 	realUnique :: FastInt,
-   	idType     :: Type,
-	idInfo     :: IdInfo,
+   	varType    :: Type,
+	idInfo_    :: IdInfo,
 	gblDetails :: GlobalIdDetails }
 
-  | LocalId { 			-- Used for locally-defined Ids (see NOTE below)
+  | LocalId { 			-- Used for locally-defined Ids 
+				-- See Note [GlobalId/LocalId] below
 	varName    :: !Name,
 	realUnique :: FastInt,
-   	idType     :: Type,
-	idInfo     :: IdInfo,
+   	varType    :: Type,
+	idInfo_    :: IdInfo,
 	lclDetails :: LocalIdDetails }
 
 data LocalIdDetails 
@@ -94,17 +113,20 @@ data LocalIdDetails
   -- NotExported things may be discarded as dead code.
 \end{code}
 
-LocalId and GlobalId
-~~~~~~~~~~~~~~~~~~~~
+Note [GlobalId/LocalId]
+~~~~~~~~~~~~~~~~~~~~~~~
 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)
+  * never treated as a candidate by the free-variable finder;
+	it's a constant!
 
 A LocalId is 
   * bound within an expression (lambda, case, local let(rec))
   * or defined at top level in the module being compiled
+  * always treated as a candidate by the free-variable finder
 
 After CoreTidy, top-level LocalIds are turned into GlobalIds
  
@@ -166,27 +188,69 @@ setVarName var new_name
 type TyVar = Var
 
 tyVarName = varName
+tyVarKind = varType
 
 setTyVarUnique = setVarUnique
 setTyVarName   = setVarName
+
+setTyVarKind :: TyVar -> Kind -> TyVar
+setTyVarKind tv k = tv {varType = k}
 \end{code}
 
 \begin{code}
 mkTyVar :: Name -> Kind -> TyVar
-mkTyVar name kind = TyVar { varName    = name
+mkTyVar name kind = ASSERT( not (isCoercionKind kind ) )
+		    TyVar { varName    = name
 			  , realUnique = getKey# (nameUnique name)
-			  , tyVarKind  = kind
+			  , varType  = kind
+                          , isCoercionVar    = False
 			}
 
 mkTcTyVar :: Name -> Kind -> TcTyVarDetails -> TyVar
 mkTcTyVar name kind details
-  = TcTyVar {	varName    = name,
+  = -- TOM: no longer valid assertion? 
+    -- ASSERT( not (isCoercionKind kind) )
+    TcTyVar {	varName    = name,
 		realUnique = getKey# (nameUnique name),
-		tyVarKind  = kind,
+		varType  = kind,
 		tcTyVarDetails = details
 	}
 \end{code}
 
+%************************************************************************
+%*									*
+\subsection{Coercion variables}
+%*									*
+%************************************************************************
+
+\begin{code}
+type CoVar = Var	-- A coercion variable is simply a type 
+			-- variable of kind (ty1 :=: ty2)
+coVarName = varName
+
+setCoVarUnique = setVarUnique
+setCoVarName   = setVarName
+
+mkCoVar :: Name -> Kind -> CoVar
+mkCoVar name kind = ASSERT( isCoercionKind kind )
+		    TyVar { varName    = name
+			  , realUnique = getKey# (nameUnique name)
+			  , varType  = kind
+                          , isCoercionVar    = True
+			}
+
+mkWildCoVar :: Kind -> TyVar
+-- A type variable that is never referred to,
+-- so its unique doesn't matter
+mkWildCoVar kind 
+  = ASSERT( isCoercionKind kind )
+    TyVar { varName = mkSysTvName wild_uniq FSLIT("co_wild"),
+            realUnique = _ILIT(1),
+            varType = kind,
+            isCoercionVar = True }
+  where
+    wild_uniq = mkBuiltinUnique 1
+\end{code}
 
 %************************************************************************
 %*									*
@@ -204,6 +268,7 @@ type DictId = Id
 \begin{code}
 idName    = varName
 idUnique  = varUnique
+idType    = varType
 
 setIdUnique :: Id -> Unique -> Id
 setIdUnique = setVarUnique
@@ -212,7 +277,7 @@ setIdName :: Id -> Name -> Id
 setIdName = setVarName
 
 setIdType :: Id -> Type -> Id
-setIdType id ty = id {idType = ty}
+setIdType id ty = id {varType = ty}
 
 setIdExported :: Id -> Id
 -- Can be called on GlobalIds, such as data cons and class ops,
@@ -228,29 +293,32 @@ 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,
+			   	    varType    = varType id,
+				    idInfo_    = idInfo id,
 				    gblDetails = details }
 
+idInfo :: Id -> IdInfo
+idInfo (GlobalId {idInfo_ = info}) = info
+idInfo (LocalId  {idInfo_ = info}) = info
+idInfo other_var		   = pprPanic "idInfo" (ppr other_var)
+
 lazySetIdInfo :: Id -> IdInfo -> Id
-lazySetIdInfo id info = id {idInfo = info}
+lazySetIdInfo id info = id {idInfo_ = info}
 
 setIdInfo :: Id -> IdInfo -> Id
-setIdInfo id info = seqIdInfo info `seq` id {idInfo = 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 id
-  = seqIdInfo new_info `seq` id {idInfo = new_info}
+  = 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 id
-  = case fn (idInfo id) of
-	Nothing       -> id
-	Just new_info -> id {idInfo = new_info}
+maybeModifyIdInfo :: Maybe IdInfo -> Id -> Id
+maybeModifyIdInfo (Just new_info) id = id {idInfo_ = new_info}
+maybeModifyIdInfo Nothing	  id = id
 \end{code}
 
 %************************************************************************
@@ -264,17 +332,17 @@ mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
 mkGlobalId details name ty info 
   = GlobalId {	varName    = name, 
 		realUnique = getKey# (nameUnique name), 	-- Cache the unique
-		idType     = ty,	
+		varType     = ty,	
 		gblDetails = details,
-		idInfo     = info }
+		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,	
+		varType     = ty,	
 		lclDetails = details,
-		idInfo     = info }
+		idInfo_    = info }
 
 mkLocalId :: Name -> Type -> IdInfo -> Id
 mkLocalId name ty info = mk_local_id name ty NotExported info
@@ -303,6 +371,9 @@ isId other	   = False
 isLocalId (LocalId {}) = True
 isLocalId other	       = False
 
+isCoVar (v@(TyVar {})) = isCoercionVar v
+isCoVar 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.