Interface file optimisation and removal of nameParent

This large commit combines several interrelated changes:

  - IfaceSyn now contains actual Names rather than the special
    IfaceExtName type.  The binary interface file contains
    a symbol table of Names, where each entry is a (package,
    ModuleName, OccName) triple.  Names in the IfaceSyn point
    to entries in the symbol table.

    This reduces the size of interface files, which should
    hopefully improve performance (not measured yet).

    The toIfaceXXX functions now do not need to pass around
    a function from Name -> IfaceExtName, which makes that
    code simpler.

  - Names now do not point directly to their parents, and the
    nameParent operation has gone away.  It turned out to be hard to
    keep this information consistent in practice, and the parent info
    was only valid in some Names.  Instead we made the following
    changes:

    * ImportAvails contains a new field 
          imp_parent :: NameEnv AvailInfo
      which gives the family info for any Name in scope, and
      is used by the renamer when renaming export lists, amongst
      other things.  This info is thrown away after renaming.

    * The mi_ver_fn field of ModIface now maps to
      (OccName,Version) instead of just Version, where the
      OccName is the parent name.  This mapping is used when
      constructing the usage info for dependent modules.
      There may be entries in mi_ver_fn for things that are not in
      scope, whereas imp_parent only deals with in-scope things.

    * The md_exports field of ModDetails now contains
      [AvailInfo] rather than NameSet.  This gives us
      family info for the exported names of a module.

Also:

   - ifaceDeclSubBinders moved to IfaceSyn (seems like the
     right place for it).

   - heavily refactored renaming of import/export lists.

   - Unfortunately external core is now broken, as it relied on
     IfaceSyn.  It requires some attention.

3 files changed, 60 insertions, 69 deletions

diff --git a/compiler/prelude/PrelNames.lhs b/compiler/prelude/PrelNames.lhs
index 36413dd18a..bccf84fa1d 100644
--- a/compiler/prelude/PrelNames.lhs
+++ b/compiler/prelude/PrelNames.lhs
@@ -446,9 +446,9 @@ runMainIOName = varQual gHC_TOP_HANDLER FSLIT("runMainIO") runMainKey
 
 orderingTyConName = tcQual   gHC_BASE FSLIT("Ordering") orderingTyConKey
 
-eitherTyConName	  = tcQual  dATA_EITHER     FSLIT("Either") eitherTyConKey
-leftDataConName   = conName eitherTyConName FSLIT("Left")   leftDataConKey
-rightDataConName  = conName eitherTyConName FSLIT("Right")  rightDataConKey
+eitherTyConName	  = tcQual  dATA_EITHER FSLIT("Either") eitherTyConKey
+leftDataConName   = conName dATA_EITHER FSLIT("Left")   leftDataConKey
+rightDataConName  = conName dATA_EITHER FSLIT("Right")  rightDataConKey
 
 -- Generics
 crossTyConName     = tcQual   gHC_BASE FSLIT(":*:") crossTyConKey
@@ -466,18 +466,18 @@ eqStringName	 	= varQual gHC_BASE FSLIT("eqString")  eqStringIdKey
 inlineIdName	 	= varQual gHC_BASE FSLIT("inline") inlineIdKey
 
 -- Base classes (Eq, Ord, Functor)
-eqClassName	  = clsQual gHC_BASE FSLIT("Eq")      eqClassKey
-eqName		  = methName eqClassName FSLIT("==")   eqClassOpKey
-ordClassName	  = clsQual gHC_BASE FSLIT("Ord")     ordClassKey
-geName		  = methName ordClassName FSLIT(">=")  geClassOpKey
-functorClassName  = clsQual gHC_BASE FSLIT("Functor") functorClassKey
+eqClassName	  = clsQual  gHC_BASE FSLIT("Eq")      eqClassKey
+eqName		  = methName gHC_BASE FSLIT("==")      eqClassOpKey
+ordClassName	  = clsQual  gHC_BASE FSLIT("Ord")     ordClassKey
+geName		  = methName gHC_BASE FSLIT(">=")      geClassOpKey
+functorClassName  = clsQual  gHC_BASE FSLIT("Functor") functorClassKey
 
 -- Class Monad
-monadClassName	   = clsQual gHC_BASE FSLIT("Monad")        monadClassKey
-thenMName	   = methName monadClassName FSLIT(">>")     thenMClassOpKey
-bindMName	   = methName monadClassName FSLIT(">>=")    bindMClassOpKey
-returnMName	   = methName monadClassName FSLIT("return") returnMClassOpKey
-failMName	   = methName monadClassName FSLIT("fail")   failMClassOpKey
+monadClassName	   = clsQual  gHC_BASE FSLIT("Monad")  monadClassKey
+thenMName	   = methName gHC_BASE FSLIT(">>")     thenMClassOpKey
+bindMName	   = methName gHC_BASE FSLIT(">>=")    bindMClassOpKey
+returnMName	   = methName gHC_BASE FSLIT("return") returnMClassOpKey
+failMName	   = methName gHC_BASE FSLIT("fail")   failMClassOpKey
 
 -- Random PrelBase functions
 otherwiseIdName   = varQual gHC_BASE FSLIT("otherwise")  otherwiseIdKey
@@ -506,25 +506,25 @@ fstName		  = varQual dATA_TUP FSLIT("fst") fstIdKey
 sndName		  = varQual dATA_TUP FSLIT("snd") sndIdKey
 
 -- Module PrelNum
-numClassName	  = clsQual gHC_NUM FSLIT("Num") numClassKey
-fromIntegerName   = methName numClassName FSLIT("fromInteger") fromIntegerClassOpKey
-minusName	  = methName numClassName FSLIT("-") minusClassOpKey
-negateName	  = methName numClassName FSLIT("negate") negateClassOpKey
-plusIntegerName   = varQual gHC_NUM FSLIT("plusInteger") plusIntegerIdKey
-timesIntegerName  = varQual gHC_NUM FSLIT("timesInteger") timesIntegerIdKey
-integerTyConName  = tcQual  gHC_NUM FSLIT("Integer") integerTyConKey
-smallIntegerDataConName = conName integerTyConName FSLIT("S#") smallIntegerDataConKey
-largeIntegerDataConName = conName integerTyConName FSLIT("J#") largeIntegerDataConKey
+numClassName	  = clsQual  gHC_NUM FSLIT("Num") numClassKey
+fromIntegerName   = methName gHC_NUM FSLIT("fromInteger") fromIntegerClassOpKey
+minusName	  = methName gHC_NUM FSLIT("-") minusClassOpKey
+negateName	  = methName gHC_NUM FSLIT("negate") negateClassOpKey
+plusIntegerName   = varQual  gHC_NUM FSLIT("plusInteger") plusIntegerIdKey
+timesIntegerName  = varQual  gHC_NUM FSLIT("timesInteger") timesIntegerIdKey
+integerTyConName  = tcQual   gHC_NUM FSLIT("Integer") integerTyConKey
+smallIntegerDataConName = conName gHC_NUM FSLIT("S#") smallIntegerDataConKey
+largeIntegerDataConName = conName gHC_NUM FSLIT("J#") largeIntegerDataConKey
 
 -- PrelReal types and classes
-rationalTyConName   = tcQual  gHC_REAL  FSLIT("Rational") rationalTyConKey
-ratioTyConName	    = tcQual  gHC_REAL  FSLIT("Ratio") ratioTyConKey
-ratioDataConName    = conName ratioTyConName FSLIT(":%") ratioDataConKey
-realClassName	    = clsQual gHC_REAL  FSLIT("Real") realClassKey
-integralClassName   = clsQual gHC_REAL  FSLIT("Integral") integralClassKey
-realFracClassName   = clsQual gHC_REAL  FSLIT("RealFrac") realFracClassKey
-fractionalClassName = clsQual gHC_REAL  FSLIT("Fractional") fractionalClassKey
-fromRationalName    = methName fractionalClassName  FSLIT("fromRational") fromRationalClassOpKey
+rationalTyConName   = tcQual  gHC_REAL FSLIT("Rational") rationalTyConKey
+ratioTyConName	    = tcQual  gHC_REAL FSLIT("Ratio") ratioTyConKey
+ratioDataConName    = conName gHC_REAL FSLIT(":%") ratioDataConKey
+realClassName	    = clsQual gHC_REAL FSLIT("Real") realClassKey
+integralClassName   = clsQual gHC_REAL FSLIT("Integral") integralClassKey
+realFracClassName   = clsQual gHC_REAL FSLIT("RealFrac") realFracClassKey
+fractionalClassName = clsQual gHC_REAL FSLIT("Fractional") fractionalClassKey
+fromRationalName    = methName gHC_REAL  FSLIT("fromRational") fromRationalClassOpKey
 
 -- PrelFloat classes
 floatingClassName  = clsQual  gHC_FLOAT FSLIT("Floating") floatingClassKey
@@ -555,10 +555,10 @@ assertErrorName	  = varQual gHC_ERR FSLIT("assertError") assertErrorIdKey
 
 -- Enum module (Enum, Bounded)
 enumClassName 	   = clsQual gHC_ENUM FSLIT("Enum") enumClassKey
-enumFromName	   = methName enumClassName FSLIT("enumFrom") enumFromClassOpKey
-enumFromToName	   = methName enumClassName FSLIT("enumFromTo") enumFromToClassOpKey
-enumFromThenName   = methName enumClassName FSLIT("enumFromThen") enumFromThenClassOpKey
-enumFromThenToName = methName enumClassName FSLIT("enumFromThenTo") enumFromThenToClassOpKey
+enumFromName	   = methName gHC_ENUM FSLIT("enumFrom") enumFromClassOpKey
+enumFromToName	   = methName gHC_ENUM FSLIT("enumFromTo") enumFromToClassOpKey
+enumFromThenName   = methName gHC_ENUM FSLIT("enumFromThen") enumFromThenClassOpKey
+enumFromThenToName = methName gHC_ENUM FSLIT("enumFromThenTo") enumFromThenToClassOpKey
 boundedClassName   = clsQual gHC_ENUM FSLIT("Bounded") boundedClassKey
 
 -- List functions
@@ -590,7 +590,7 @@ indexOfPName      = varQual gHC_PARR FSLIT("indexOfP")     indexOfPIdKey
 
 -- IOBase things
 ioTyConName	  = tcQual  gHC_IO_BASE FSLIT("IO") ioTyConKey
-ioDataConName     = conName ioTyConName  FSLIT("IO") ioDataConKey
+ioDataConName     = conName gHC_IO_BASE FSLIT("IO") ioDataConKey
 thenIOName	  = varQual gHC_IO_BASE FSLIT("thenIO") thenIOIdKey
 bindIOName	  = varQual gHC_IO_BASE FSLIT("bindIO") bindIOIdKey
 returnIOName	  = varQual gHC_IO_BASE FSLIT("returnIO") returnIOIdKey
@@ -611,7 +611,7 @@ word16TyConName   = tcQual  gHC_WORD FSLIT("Word16") word16TyConKey
 word32TyConName   = tcQual  gHC_WORD FSLIT("Word32") word32TyConKey
 word64TyConName   = tcQual  gHC_WORD FSLIT("Word64") word64TyConKey
 wordTyConName     = tcQual  gHC_WORD FSLIT("Word")   wordTyConKey
-wordDataConName   = conName wordTyConName FSLIT("W#") wordDataConKey
+wordDataConName   = conName gHC_WORD FSLIT("W#") wordDataConKey
 
 -- PrelPtr module
 ptrTyConName	  = tcQual   gHC_PTR FSLIT("Ptr") ptrTyConKey
@@ -626,7 +626,7 @@ runSTRepName	   = varQual gHC_ST  FSLIT("runSTRep") runSTRepIdKey
 
 -- Recursive-do notation
 monadFixClassName  = clsQual mONAD_FIX FSLIT("MonadFix") monadFixClassKey
-mfixName	   = methName monadFixClassName FSLIT("mfix") mfixIdKey
+mfixName	   = methName mONAD_FIX FSLIT("mfix") mfixIdKey
 
 -- Arrow notation
 arrAName	   = varQual aRROW FSLIT("arr")	  arrAIdKey
@@ -666,20 +666,15 @@ tcQual   = mk_known_key_name tcName
 clsQual  = mk_known_key_name clsName
 
 mk_known_key_name space mod str uniq 
-  = mkExternalName uniq mod (mkOccNameFS space str) 
-		   Nothing noSrcLoc
-
-conName :: Name -> FastString -> Unique -> Name
--- Be careful to ghve constructor names the right parent!
-conName tycon occ uniq
-  = mkExternalName uniq (nameModule tycon) (mkOccNameFS dataName occ) 
-		   (Just tycon) noSrcLoc
-
-methName :: Name -> FastString -> Unique -> Name
--- Be careful to ghve method names the right parent!
-methName cls occ uniq
-  = mkExternalName uniq (nameModule cls) (mkVarOccFS occ) 
-		   (Just cls) noSrcLoc
+  = mkExternalName uniq mod (mkOccNameFS space str) noSrcLoc
+
+conName :: Module -> FastString -> Unique -> Name
+conName mod occ uniq
+  = mkExternalName uniq mod (mkOccNameFS dataName occ) noSrcLoc
+
+methName :: Module -> FastString -> Unique -> Name
+methName mod occ uniq
+  = mkExternalName uniq mod (mkVarOccFS occ) noSrcLoc
 \end{code}
 
 %************************************************************************
diff --git a/compiler/prelude/TysPrim.lhs b/compiler/prelude/TysPrim.lhs
index 4b6832a856..7a316835ea 100644
--- a/compiler/prelude/TysPrim.lhs
+++ b/compiler/prelude/TysPrim.lhs
@@ -103,7 +103,6 @@ mkPrimTc :: FastString -> Unique -> TyCon -> Name
 mkPrimTc fs uniq tycon
   = mkWiredInName gHC_PRIM (mkOccNameFS tcName fs) 
 		  uniq
-		  Nothing 		-- No parent object
 		  (ATyCon tycon)	-- Relevant TyCon
 		  UserSyntax		-- None are built-in syntax
 
diff --git a/compiler/prelude/TysWiredIn.lhs b/compiler/prelude/TysWiredIn.lhs
index 598fa42032..436b121adc 100644
--- a/compiler/prelude/TysWiredIn.lhs
+++ b/compiler/prelude/TysWiredIn.lhs
@@ -133,36 +133,34 @@ wiredInTyCons = [ unitTyCon	-- Not treated like other tuples, because
 mkWiredInTyConName :: BuiltInSyntax -> Module -> FastString -> Unique -> TyCon -> Name
 mkWiredInTyConName built_in mod fs uniq tycon
   = mkWiredInName mod (mkOccNameFS tcName fs) uniq
-		  Nothing 		-- No parent object
 		  (ATyCon tycon)	-- Relevant TyCon
 		  built_in
 
-mkWiredInDataConName :: BuiltInSyntax -> Module -> FastString -> Unique -> DataCon -> Name -> Name
-mkWiredInDataConName built_in mod fs uniq datacon parent
+mkWiredInDataConName :: BuiltInSyntax -> Module -> FastString -> Unique -> DataCon -> Name
+mkWiredInDataConName built_in mod fs uniq datacon
   = mkWiredInName mod (mkOccNameFS dataName fs) uniq
-		  (Just parent) 	-- Name of parent TyCon
 		  (ADataCon datacon)	-- Relevant DataCon
 		  built_in
 
 charTyConName	  = mkWiredInTyConName   UserSyntax gHC_BASE FSLIT("Char") charTyConKey charTyCon
-charDataConName   = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("C#") charDataConKey charDataCon charTyConName
+charDataConName   = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("C#") charDataConKey charDataCon
 intTyConName	  = mkWiredInTyConName   UserSyntax gHC_BASE FSLIT("Int") intTyConKey   intTyCon
-intDataConName	  = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("I#") intDataConKey  intDataCon intTyConName
+intDataConName	  = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("I#") intDataConKey  intDataCon
 						  
 boolTyConName	  = mkWiredInTyConName   UserSyntax gHC_BASE FSLIT("Bool") boolTyConKey boolTyCon
-falseDataConName  = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("False") falseDataConKey falseDataCon boolTyConName
-trueDataConName	  = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("True")  trueDataConKey  trueDataCon  boolTyConName
+falseDataConName  = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("False") falseDataConKey falseDataCon
+trueDataConName	  = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("True")  trueDataConKey  trueDataCon 
 listTyConName	  = mkWiredInTyConName   BuiltInSyntax gHC_BASE FSLIT("[]") listTyConKey listTyCon
-nilDataConName 	  = mkWiredInDataConName BuiltInSyntax gHC_BASE FSLIT("[]") nilDataConKey nilDataCon  listTyConName
-consDataConName	  = mkWiredInDataConName BuiltInSyntax gHC_BASE FSLIT(":") consDataConKey consDataCon listTyConName
+nilDataConName 	  = mkWiredInDataConName BuiltInSyntax gHC_BASE FSLIT("[]") nilDataConKey nilDataCon 
+consDataConName	  = mkWiredInDataConName BuiltInSyntax gHC_BASE FSLIT(":") consDataConKey consDataCon
 
 floatTyConName	   = mkWiredInTyConName   UserSyntax gHC_FLOAT FSLIT("Float") floatTyConKey floatTyCon
-floatDataConName   = mkWiredInDataConName UserSyntax gHC_FLOAT FSLIT("F#") floatDataConKey floatDataCon floatTyConName
+floatDataConName   = mkWiredInDataConName UserSyntax gHC_FLOAT FSLIT("F#") floatDataConKey floatDataCon
 doubleTyConName    = mkWiredInTyConName   UserSyntax gHC_FLOAT FSLIT("Double") doubleTyConKey doubleTyCon
-doubleDataConName  = mkWiredInDataConName UserSyntax gHC_FLOAT FSLIT("D#") doubleDataConKey doubleDataCon doubleTyConName
+doubleDataConName  = mkWiredInDataConName UserSyntax gHC_FLOAT FSLIT("D#") doubleDataConKey doubleDataCon
 
 parrTyConName	  = mkWiredInTyConName   BuiltInSyntax gHC_PARR FSLIT("[::]") parrTyConKey parrTyCon 
-parrDataConName   = mkWiredInDataConName UserSyntax    gHC_PARR FSLIT("PArr") parrDataConKey parrDataCon parrTyConName
+parrDataConName   = mkWiredInDataConName UserSyntax    gHC_PARR FSLIT("PArr") parrDataConKey parrDataCon
 
 boolTyCon_RDR   = nameRdrName boolTyConName
 false_RDR	= nameRdrName falseDataConName
@@ -240,7 +238,6 @@ pcDataConWithFixity declared_infix dc_name tyvars arg_tys tycon
     wrk_occ  = mkDataConWorkerOcc (nameOccName dc_name)
     wrk_key  = incrUnique (nameUnique dc_name)
     wrk_name = mkWiredInName mod wrk_occ wrk_key
-			     (Just (tyConName tycon))
 			     (AnId (dataConWorkId data_con)) UserSyntax
     bogus_wrap_name = pprPanic "Wired-in data wrapper id" (ppr dc_name)
 	-- Wired-in types are too simple to need wrappers
@@ -274,7 +271,7 @@ mk_tuple boxity arity = (tycon, tuple_con)
 	tycon   = mkTupleTyCon tc_name tc_kind arity tyvars tuple_con boxity gen_info 
 	mod	= mkTupleModule boxity arity
 	tc_name = mkWiredInName mod (mkTupleOcc tcName boxity arity) tc_uniq
-				Nothing (ATyCon tycon) BuiltInSyntax
+				(ATyCon tycon) BuiltInSyntax
     	tc_kind = mkArrowKinds (map tyVarKind tyvars) res_kind
 	res_kind | isBoxed boxity = liftedTypeKind
 		 | otherwise	  = ubxTupleKind
@@ -285,7 +282,7 @@ mk_tuple boxity arity = (tycon, tuple_con)
 	tuple_con = pcDataCon dc_name tyvars tyvar_tys tycon
 	tyvar_tys = mkTyVarTys tyvars
 	dc_name   = mkWiredInName mod (mkTupleOcc dataName boxity arity) dc_uniq
-				  (Just tc_name) (ADataCon tuple_con) BuiltInSyntax
+				  (ADataCon tuple_con) BuiltInSyntax
  	tc_uniq   = mkTupleTyConUnique   boxity arity
 	dc_uniq   = mkTupleDataConUnique boxity arity
 	gen_info  = True		-- Tuples all have generics..
@@ -569,7 +566,7 @@ mkPArrFakeCon arity  = data_con
 	tyvarTys  = replicate arity $ mkTyVarTy tyvar
         nameStr   = mkFastString ("MkPArr" ++ show arity)
 	name      = mkWiredInName gHC_PARR (mkOccNameFS dataName nameStr) uniq
-				  Nothing (ADataCon data_con) UserSyntax
+				  (ADataCon data_con) UserSyntax
 	uniq      = mkPArrDataConUnique arity
 
 -- checks whether a data constructor is a fake constructor for parallel arrays