[project @ 2004-08-26 15:44:50 by simonpj]

[ghc-hetmet.git] / ghc / compiler / basicTypes / MkId.lhs

diff --git a/ghc/compiler/basicTypes/MkId.lhs b/ghc/compiler/basicTypes/MkId.lhs
index 60e0c8d..dcd057d 100644 (file)
--- a/ghc/compiler/basicTypes/MkId.lhs
+++ b/ghc/compiler/basicTypes/MkId.lhs
@@ -16,7 +16,7 @@ module MkId (
        mkDictFunId, mkDefaultMethodId,
        mkDictSelId, 
 
        mkDictFunId, mkDefaultMethodId,
        mkDictSelId, 
 

-       mkDataConId, mkDataConWrapId,
+       mkDataConIds,

        mkRecordSelId, 
        mkPrimOpId, mkFCallId,
 
        mkRecordSelId, 
        mkPrimOpId, mkFCallId,
 

@@ -30,19 +30,20 @@ module MkId (
        mkRuntimeErrorApp,
        rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID, rUNTIME_ERROR_ID,
        nON_EXHAUSTIVE_GUARDS_ERROR_ID, nO_METHOD_BINDING_ERROR_ID,
        mkRuntimeErrorApp,
        rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID, rUNTIME_ERROR_ID,
        nON_EXHAUSTIVE_GUARDS_ERROR_ID, nO_METHOD_BINDING_ERROR_ID,

-       pAT_ERROR_ID
+       pAT_ERROR_ID, eRROR_ID

     ) where
 
 #include "HsVersions.h"
 
 
 import BasicTypes      ( Arity, StrictnessMark(..), isMarkedUnboxed, isMarkedStrict )
     ) where
 
 #include "HsVersions.h"
 
 
 import BasicTypes      ( Arity, StrictnessMark(..), isMarkedUnboxed, isMarkedStrict )

-import TysPrim         ( openAlphaTyVars, alphaTyVar, alphaTy, betaTyVar, betaTy,
-                         intPrimTy, realWorldStatePrimTy, addrPrimTy
+import TysPrim         ( openAlphaTyVars, alphaTyVar, alphaTy, 
+                         realWorldStatePrimTy, addrPrimTy

                        )
 import TysWiredIn      ( charTy, mkListTy )
 import PrelRules       ( primOpRules )
 import Rules           ( addRule )
                        )
 import TysWiredIn      ( charTy, mkListTy )
 import PrelRules       ( primOpRules )
 import Rules           ( addRule )

+import Type            ( TyThing(..) )

 import TcType          ( Type, ThetaType, mkDictTy, mkPredTys, mkTyConApp,
                          mkTyVarTys, mkClassPred, tcEqPred,
                          mkFunTys, mkFunTy, mkSigmaTy, tcSplitSigmaTy, 
 import TcType          ( Type, ThetaType, mkDictTy, mkPredTys, mkTyConApp,
                          mkTyVarTys, mkClassPred, tcEqPred,
                          mkFunTys, mkFunTy, mkSigmaTy, tcSplitSigmaTy, 

@@ -57,36 +58,35 @@ import TyCon                ( TyCon, isNewTyCon, tyConTyVars, tyConDataCons,
 import Class           ( Class, classTyCon, classTyVars, classSelIds )
 import Var             ( Id, TyVar, Var )
 import VarSet          ( isEmptyVarSet )
 import Class           ( Class, classTyCon, classTyVars, classSelIds )
 import Var             ( Id, TyVar, Var )
 import VarSet          ( isEmptyVarSet )

-import Name            ( mkFCallName, Name )
-import PrimOp          ( PrimOp(DataToTagOp), primOpSig, mkPrimOpIdName )
+import Name            ( mkFCallName, mkWiredInName, Name, BuiltInSyntax(..) )
+import OccName         ( mkOccFS, varName )
+import PrimOp          ( PrimOp, primOpSig, primOpOcc, primOpTag )

 import ForeignCall     ( ForeignCall )
 import ForeignCall     ( ForeignCall )

-import DataCon         ( DataCon, 
-                         dataConFieldLabels, dataConRepArity, dataConTyCon,
+import DataCon         ( DataCon, DataConIds(..),
+                         dataConFieldLabels, dataConRepArity, 

                          dataConArgTys, dataConRepType, 
                          dataConArgTys, dataConRepType, 

-                         dataConOrigArgTys,
-                          dataConName, dataConTheta,
-                         dataConSig, dataConStrictMarks, dataConWorkId,
+                         dataConOrigArgTys, dataConTheta,
+                         dataConSig, dataConStrictMarks, dataConExStricts, 

                          splitProductType
                        )
                          splitProductType
                        )

-import Id              ( idType, mkGlobalId, mkVanillaGlobal, mkSysLocal,
-                         mkTemplateLocals, mkTemplateLocalsNum,
-                         mkTemplateLocal, idNewStrictness, idName
+import Id              ( idType, mkGlobalId, mkVanillaGlobal, mkSysLocal, 
+                         mkTemplateLocals, mkTemplateLocalsNum, mkExportedLocalId,
+                         mkTemplateLocal, idName

                        )
                        )

-import IdInfo          ( IdInfo, noCafIdInfo, hasCafIdInfo,
-                         setUnfoldingInfo, 
+import IdInfo          ( IdInfo, noCafIdInfo,  setUnfoldingInfo, 

                          setArityInfo, setSpecInfo, setCafInfo,
                          setArityInfo, setSpecInfo, setCafInfo,

-                         setAllStrictnessInfo,
+                         setAllStrictnessInfo, vanillaIdInfo,

                          GlobalIdDetails(..), CafInfo(..)
                        )
                          GlobalIdDetails(..), CafInfo(..)
                        )

-import NewDemand       ( mkStrictSig, strictSigResInfo, DmdResult(..),
+import NewDemand       ( mkStrictSig, DmdResult(..),

                          mkTopDmdType, topDmd, evalDmd, lazyDmd, retCPR,
                          Demand(..), Demands(..) )
                          mkTopDmdType, topDmd, evalDmd, lazyDmd, retCPR,
                          Demand(..), Demands(..) )

-import FieldLabel      ( mkFieldLabel, fieldLabelName, 
-                         firstFieldLabelTag, allFieldLabelTags, fieldLabelType
+import FieldLabel      ( fieldLabelName, firstFieldLabelTag, 
+                         allFieldLabelTags, fieldLabelType

                        )
 import DmdAnal         ( dmdAnalTopRhs )
 import CoreSyn
                        )
 import DmdAnal         ( dmdAnalTopRhs )
 import CoreSyn

-import Unique          ( mkBuiltinUnique )
+import Unique          ( mkBuiltinUnique, mkPrimOpIdUnique )

 import Maybes
 import PrelNames
 import Maybe            ( isJust )
 import Maybes
 import PrelNames
 import Maybe            ( isJust )

@@ -138,7 +138,6 @@ ghcPrimIds
     realWorldPrimId,
     unsafeCoerceId,
     nullAddrId,
     realWorldPrimId,
     unsafeCoerceId,
     nullAddrId,

-    getTagId,

     seqId
     ]
 \end{code}
     seqId
     ]
 \end{code}

@@ -149,57 +148,6 @@ ghcPrimIds
 %*                                                                     *
 %************************************************************************
 
 %*                                                                     *
 %************************************************************************
 

-\begin{code}
-mkDataConId :: Name -> DataCon -> Id
-       -- Makes the *worker* for the data constructor; that is, the function
-       -- that takes the reprsentation arguments and builds the constructor.
-mkDataConId work_name data_con
-  = mkGlobalId (DataConId data_con) work_name (dataConRepType data_con) info
-  where
-    info = noCafIdInfo
-          `setArityInfo`               arity
-          `setAllStrictnessInfo`       Just strict_sig
-
-    arity      = dataConRepArity data_con
-
-    strict_sig = mkStrictSig (mkTopDmdType (replicate arity topDmd) cpr_info)
-       -- Notice that we do *not* say the worker is strict
-       -- even if the data constructor is declared strict
-       --      e.g.    data T = MkT !(Int,Int)
-       -- Why?  Because the *wrapper* is strict (and its unfolding has case
-       -- expresssions that do the evals) but the *worker* itself is not.
-       -- If we pretend it is strict then when we see
-       --      case x of y -> $wMkT y
-       -- the simplifier thinks that y is "sure to be evaluated" (because
-       -- $wMkT is strict) and drops the case.  No, $wMkT is not strict.
-       --
-       -- When the simplifer sees a pattern 
-       --      case e of MkT x -> ...
-       -- it uses the dataConRepStrictness of MkT to mark x as evaluated;
-       -- but that's fine... dataConRepStrictness comes from the data con
-       -- not from the worker Id.
-
-    tycon = dataConTyCon data_con
-    cpr_info | isProductTyCon tycon && 
-              isDataTyCon tycon    &&
-              arity > 0            &&
-              arity <= mAX_CPR_SIZE    = retCPR
-            | otherwise                = TopRes
-       -- RetCPR is only true for products that are real data types;
-       -- that is, not unboxed tuples or [non-recursive] newtypes
-
-mAX_CPR_SIZE :: Arity
-mAX_CPR_SIZE = 10
--- We do not treat very big tuples as CPR-ish:
---     a) for a start we get into trouble because there aren't 
---        "enough" unboxed tuple types (a tiresome restriction, 
---        but hard to fix), 
---     b) more importantly, big unboxed tuples get returned mainly
---        on the stack, and are often then allocated in the heap
---        by the caller.  So doing CPR for them may in fact make
---        things worse.
-\end{code}
-

 The wrapper for a constructor is an ordinary top-level binding that evaluates
 any strict args, unboxes any args that are going to be flattened, and calls
 the worker.
 The wrapper for a constructor is an ordinary top-level binding that evaluates
 any strict args, unboxes any args that are going to be flattened, and calls
 the worker.

@@ -237,23 +185,94 @@ Notice that
   Making an explicit case expression allows the simplifier to eliminate
   it in the (common) case where the constructor arg is already evaluated.
 
   Making an explicit case expression allows the simplifier to eliminate
   it in the (common) case where the constructor arg is already evaluated.
 

+

 \begin{code}
 \begin{code}

-mkDataConWrapId data_con
-  = mkGlobalId (DataConWrapId data_con) (dataConName data_con) wrap_ty info
+mkDataConIds :: Name -> Name -> DataCon -> DataConIds
+       -- Makes the *worker* for the data constructor; that is, the function
+       -- that takes the reprsentation arguments and builds the constructor.
+mkDataConIds wrap_name wkr_name data_con
+  | isNewTyCon tycon
+  = NewDC nt_wrap_id
+
+  | any isMarkedStrict all_strict_marks                -- Algebraic, needs wrapper
+  = AlgDC (Just alg_wrap_id) wrk_id
+
+  | otherwise                                  -- Algebraic, no wrapper
+  = AlgDC Nothing wrk_id

   where
   where

-    work_id = dataConWorkId data_con
+    (tyvars, _, ex_tyvars, ex_theta, orig_arg_tys, tycon) = dataConSig data_con
+    all_tyvars = tyvars ++ ex_tyvars

 
 

-    info = noCafIdInfo
-          `setUnfoldingInfo`   wrap_unf
-               -- The NoCaf-ness is set by noCafIdInfo
-          `setArityInfo`       arity
-               -- It's important to specify the arity, so that partial
-               -- applications are treated as values
-          `setAllStrictnessInfo`       Just wrap_sig
-
-    wrap_sig = mkStrictSig (mkTopDmdType arg_dmds res_info)
-    res_info = strictSigResInfo (idNewStrictness work_id)
-    arg_dmds = map mk_dmd strict_marks
+    ex_dict_tys  = mkPredTys ex_theta
+    all_arg_tys  = ex_dict_tys ++ orig_arg_tys
+    result_ty    = mkTyConApp tycon (mkTyVarTys tyvars)
+
+    wrap_ty = mkForAllTys all_tyvars (mkFunTys all_arg_tys result_ty)
+       -- We used to include the stupid theta in the wrapper's args
+       -- but now we don't.  Instead the type checker just injects these
+       -- extra constraints where necessary.
+
+       ----------- Worker (algebraic data types only) --------------
+    wrk_id = mkGlobalId (DataConWorkId data_con) wkr_name
+                       (dataConRepType data_con) wkr_info
+
+    wkr_arity = dataConRepArity data_con
+    wkr_info  = noCafIdInfo
+               `setArityInfo`          wkr_arity
+               `setAllStrictnessInfo`  Just wkr_sig
+
+    wkr_sig = mkStrictSig (mkTopDmdType (replicate wkr_arity topDmd) cpr_info)
+       -- Notice that we do *not* say the worker is strict
+       -- even if the data constructor is declared strict
+       --      e.g.    data T = MkT !(Int,Int)
+       -- Why?  Because the *wrapper* is strict (and its unfolding has case
+       -- expresssions that do the evals) but the *worker* itself is not.
+       -- If we pretend it is strict then when we see
+       --      case x of y -> $wMkT y
+       -- the simplifier thinks that y is "sure to be evaluated" (because
+       -- $wMkT is strict) and drops the case.  No, $wMkT is not strict.
+       --
+       -- When the simplifer sees a pattern 
+       --      case e of MkT x -> ...
+       -- it uses the dataConRepStrictness of MkT to mark x as evaluated;
+       -- but that's fine... dataConRepStrictness comes from the data con
+       -- not from the worker Id.
+
+    cpr_info | isProductTyCon tycon && 
+              isDataTyCon tycon    &&
+              wkr_arity > 0        &&
+              wkr_arity <= mAX_CPR_SIZE        = retCPR
+            | otherwise                        = TopRes
+       -- RetCPR is only true for products that are real data types;
+       -- that is, not unboxed tuples or [non-recursive] newtypes
+
+       ----------- Wrappers for newtypes --------------
+    nt_wrap_id   = mkGlobalId (DataConWrapId data_con) wrap_name wrap_ty nt_wrap_info
+    nt_wrap_info = noCafIdInfo         -- The NoCaf-ness is set by noCafIdInfo
+                 `setArityInfo` 1      -- Arity 1
+                 `setUnfoldingInfo`     newtype_unf
+    newtype_unf  = ASSERT( null ex_tyvars && null ex_theta && 
+                         isSingleton orig_arg_tys )
+                  -- No existentials on a newtype, but it can have a context
+                  -- e.g.      newtype Eq a => T a = MkT (...)
+                  mkTopUnfolding $ Note InlineMe $
+                  mkLams tyvars $ Lam id_arg1 $ 
+                  mkNewTypeBody tycon result_ty (Var id_arg1)
+
+    id_arg1 = mkTemplateLocal 1 (head orig_arg_tys)
+
+       ----------- Wrappers for algebraic data types -------------- 
+    alg_wrap_id = mkGlobalId (DataConWrapId data_con) wrap_name wrap_ty alg_wrap_info
+    alg_wrap_info = noCafIdInfo                -- The NoCaf-ness is set by noCafIdInfo
+                   `setArityInfo`         alg_arity
+                       -- It's important to specify the arity, so that partial
+                       -- applications are treated as values
+                   `setUnfoldingInfo`     alg_unf
+                   `setAllStrictnessInfo` Just wrap_sig
+
+    all_strict_marks = dataConExStricts data_con ++ dataConStrictMarks data_con
+    wrap_sig = mkStrictSig (mkTopDmdType arg_dmds cpr_info)
+    arg_dmds = map mk_dmd all_strict_marks

     mk_dmd str | isMarkedStrict str = evalDmd
               | otherwise          = lazyDmd
        -- The Cpr info can be important inside INLINE rhss, where the
     mk_dmd str | isMarkedStrict str = evalDmd
               | otherwise          = lazyDmd
        -- The Cpr info can be important inside INLINE rhss, where the

@@ -265,65 +284,19 @@ mkDataConWrapId data_con
        --      ...(let w = C x in ...(w p q)...)...
        -- we want to see that w is strict in its two arguments
 
        --      ...(let w = C x in ...(w p q)...)...
        -- we want to see that w is strict in its two arguments
 

-    wrap_unf | isNewTyCon tycon
-            = ASSERT( null ex_tyvars && null ex_dict_args && isSingleton orig_arg_tys )
-               -- No existentials on a newtype, but it can have a context
-               -- e.g.         newtype Eq a => T a = MkT (...)
-               mkTopUnfolding $ Note InlineMe $
-               mkLams tyvars $ Lam id_arg1 $ 
-               mkNewTypeBody tycon result_ty (Var id_arg1)
-
-            | not (any isMarkedStrict strict_marks)
-            = mkCompulsoryUnfolding (Var work_id)
-                       -- The common case.  Not only is this efficient,
-                       -- but it also ensures that the wrapper is replaced
-                       -- by the worker even when there are no args.
-                       --              f (:) x
-                       -- becomes 
-                       --              f $w: x
-                       -- This is really important in rule matching,
-                       -- (We could match on the wrappers,
-                       -- but that makes it less likely that rules will match
-                       -- when we bring bits of unfoldings together.)
-               --
-               -- NB:  because of this special case, (map (:) ys) turns into
-               --      (map $w: ys).  The top-level defn for (:) is never used.
-               --      This is somewhat of a bore, but I'm currently leaving it 
-               --      as is, so that there still is a top level curried (:) for
-               --      the interpreter to call.
-
-            | otherwise
-            = mkTopUnfolding $ Note InlineMe $
-              mkLams all_tyvars $ 
-              mkLams ex_dict_args $ mkLams id_args $
-              foldr mk_case con_app 
-                    (zip (ex_dict_args++id_args) strict_marks) i3 []
-
-    con_app i rep_ids = mkApps (Var work_id)
-                              (map varToCoreExpr (all_tyvars ++ reverse rep_ids))
+    alg_unf = mkTopUnfolding $ Note InlineMe $
+             mkLams all_tyvars $ 
+             mkLams ex_dict_args $ mkLams id_args $
+             foldr mk_case con_app 
+                   (zip (ex_dict_args ++ id_args) all_strict_marks)
+                   i3 []

 
 

-    (tyvars, _, ex_tyvars, ex_theta, orig_arg_tys, tycon) = dataConSig data_con
-    all_tyvars   = tyvars ++ ex_tyvars
-
-    ex_dict_tys  = mkPredTys ex_theta
-    all_arg_tys  = ex_dict_tys ++ orig_arg_tys
-    result_ty    = mkTyConApp tycon (mkTyVarTys tyvars)
-
-    wrap_ty = mkForAllTys all_tyvars (mkFunTys all_arg_tys result_ty)
-       -- We used to include the stupid theta in the wrapper's args
-       -- but now we don't.  Instead the type checker just injects these
-       -- extra constraints where necessary.
-
-    mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n)
-                  where
-                    n = length tys
+    con_app i rep_ids = mkApps (Var wrk_id)
+                              (map varToCoreExpr (all_tyvars ++ reverse rep_ids))

 
     (ex_dict_args,i2)  = mkLocals 1  ex_dict_tys
     (id_args,i3)       = mkLocals i2 orig_arg_tys
 
     (ex_dict_args,i2)  = mkLocals 1  ex_dict_tys
     (id_args,i3)       = mkLocals i2 orig_arg_tys

-    arity             = i3-1
-    (id_arg1:_)   = id_args            -- Used for newtype only
-
-    strict_marks  = dataConStrictMarks data_con
+    alg_arity         = i3-1

 
     mk_case 
           :: (Id, StrictnessMark)      -- Arg, strictness
 
     mk_case 
           :: (Id, StrictnessMark)      -- Arg, strictness

@@ -346,6 +319,21 @@ mkDataConWrapId data_con
                                        body i' (reverse con_args ++ rep_args))]
                              where 
                                (con_args, i') = mkLocals i tys
                                        body i' (reverse con_args ++ rep_args))]
                              where 
                                (con_args, i') = mkLocals i tys

+
+mAX_CPR_SIZE :: Arity
+mAX_CPR_SIZE = 10
+-- We do not treat very big tuples as CPR-ish:
+--     a) for a start we get into trouble because there aren't 
+--        "enough" unboxed tuple types (a tiresome restriction, 
+--        but hard to fix), 
+--     b) more importantly, big unboxed tuples get returned mainly
+--        on the stack, and are often then allocated in the heap
+--        by the caller.  So doing CPR for them may in fact make
+--        things worse.
+
+mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n)
+              where
+                n = length tys

 \end{code}
 
 
 \end{code}
 
 

@@ -386,19 +374,16 @@ Then we want
 (not f :: R -> forall a. a->a, which gives the type inference mechanism 
 problems at call sites)
 
 (not f :: R -> forall a. a->a, which gives the type inference mechanism 
 problems at call sites)
 

-Similarly for newtypes
+Similarly for (recursive) newtypes

 
        newtype N = MkN { unN :: forall a. a->a }
 
 
        newtype N = MkN { unN :: forall a. a->a }
 

-       unN :: forall a. N -> a -> a
-       unN = /\a -> \n:N -> coerce (a->a) n
+       unN :: forall b. N -> b -> b
+       unN = /\b -> \n:N -> (coerce (forall a. a->a) n)

 
 \begin{code}
 mkRecordSelId tycon field_label
        -- Assumes that all fields with the same field label have the same type
 
 \begin{code}
 mkRecordSelId tycon field_label
        -- Assumes that all fields with the same field label have the same type

-       --
-       -- Annoyingly, we have to pass in the unpackCString# Id, because
-       -- we can't conjure it up out of thin air

   = sel_id
   where
     sel_id     = mkGlobalId (RecordSelId field_label) (fieldLabelName field_label) selector_ty info
   = sel_id
   where
     sel_id     = mkGlobalId (RecordSelId field_label) (fieldLabelName field_label) selector_ty info

@@ -488,10 +473,10 @@ mkRecordSelId tycon field_label
              mkLams dict_ids $ mkLams field_dict_ids $
              Lam data_id     $ sel_body
 
              mkLams dict_ids $ mkLams field_dict_ids $
              Lam data_id     $ sel_body
 

-    sel_body | isNewTyCon tycon = mkNewTypeBody tycon field_tau (mk_result data_id)
+    sel_body | isNewTyCon tycon = mk_result (mkNewTypeBody tycon field_ty (Var data_id))

             | otherwise        = Case (Var data_id) data_id (default_alt ++ the_alts)
 
             | otherwise        = Case (Var data_id) data_id (default_alt ++ the_alts)
 

-    mk_result result_id = mkVarApps (mkVarApps (Var result_id) field_tyvars) field_dict_ids
+    mk_result poly_result = mkVarApps (mkVarApps poly_result field_tyvars) field_dict_ids

        -- We pull the field lambdas to the top, so we need to 
        -- apply them in the body.  For example:
        --      data T = MkT { foo :: forall a. a->a }
        -- We pull the field lambdas to the top, so we need to 
        -- apply them in the body.  For example:
        --      data T = MkT { foo :: forall a. a->a }

@@ -504,10 +489,11 @@ mkRecordSelId tycon field_label
                Nothing         -> Nothing
                Just the_arg_id -> Just (mkReboxingAlt uniqs data_con arg_ids body)
                                where
                Nothing         -> Nothing
                Just the_arg_id -> Just (mkReboxingAlt uniqs data_con arg_ids body)
                                where

-                                  body = mk_result the_arg_id
+                                  body = mk_result (Var the_arg_id)

        where
             arg_ids = mkTemplateLocalsNum field_base (dataConOrigArgTys data_con)
                        -- No need to instantiate; same tyvars in datacon as tycon
        where
             arg_ids = mkTemplateLocalsNum field_base (dataConOrigArgTys data_con)
                        -- No need to instantiate; same tyvars in datacon as tycon

+                       -- Records can't be existential, so no existential tyvars or dicts

 
            unpack_base = field_base + length arg_ids
            uniqs = map mkBuiltinUnique [unpack_base..]
 
            unpack_base = field_base + length arg_ids
            uniqs = map mkBuiltinUnique [unpack_base..]

@@ -551,7 +537,7 @@ mkReboxingAlt us con args rhs
     (DataAlt con, args', mkLets binds rhs)
 
   where
     (DataAlt con, args', mkLets binds rhs)
 
   where

-    stricts = dataConStrictMarks con
+    stricts = dataConExStricts con ++ dataConStrictMarks con

 
     go [] stricts us = ([], [])
 
 
     go [] stricts us = ([], [])
 

@@ -589,12 +575,25 @@ mkReboxingAlt us con args rhs
 Selecting a field for a dictionary.  If there is just one field, then
 there's nothing to do.  
 
 Selecting a field for a dictionary.  If there is just one field, then
 there's nothing to do.  
 

-ToDo: unify with mkRecordSelId.
+Dictionary selectors may get nested forall-types.  Thus:
+
+       class Foo a where
+         op :: forall b. Ord b => a -> b -> b
+
+Then the top-level type for op is
+
+       op :: forall a. Foo a => 
+             forall b. Ord b => 
+             a -> b -> b
+
+This is unlike ordinary record selectors, which have all the for-alls
+at the outside.  When dealing with classes it's very convenient to
+recover the original type signature from the class op selector.

 
 \begin{code}
 mkDictSelId :: Name -> Class -> Id
 mkDictSelId name clas
 
 \begin{code}
 mkDictSelId :: Name -> Class -> Id
 mkDictSelId name clas

-  = mkGlobalId (RecordSelId field_lbl) name sel_ty info
+  = mkGlobalId (ClassOpId clas) name sel_ty info

   where
     sel_ty = mkForAllTys tyvars (mkFunTy (idType dict_id) (idType the_arg_id))
        -- We can't just say (exprType rhs), because that would give a type
   where
     sel_ty = mkForAllTys tyvars (mkFunTy (idType dict_id) (idType the_arg_id))
        -- We can't just say (exprType rhs), because that would give a type

@@ -603,10 +602,9 @@ mkDictSelId name clas
        -- But it's type must expose the representation of the dictionary
        -- to gat (say)         C a -> (a -> a)
 
        -- But it's type must expose the representation of the dictionary
        -- to gat (say)         C a -> (a -> a)
 

-    field_lbl = mkFieldLabel name tycon sel_ty tag
-    tag       = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` allFieldLabelTags) name
+    tag  = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` allFieldLabelTags) name

 
 

-    info      = noCafIdInfo
+    info = noCafIdInfo

                `setArityInfo`          1
                `setUnfoldingInfo`      mkTopUnfolding rhs
                `setAllStrictnessInfo`  Just strict_sig
                `setArityInfo`          1
                `setUnfoldingInfo`      mkTopUnfolding rhs
                `setAllStrictnessInfo`  Just strict_sig

@@ -663,7 +661,9 @@ mkPrimOpId prim_op
   where
     (tyvars,arg_tys,res_ty, arity, strict_sig) = primOpSig prim_op
     ty   = mkForAllTys tyvars (mkFunTys arg_tys res_ty)
   where
     (tyvars,arg_tys,res_ty, arity, strict_sig) = primOpSig prim_op
     ty   = mkForAllTys tyvars (mkFunTys arg_tys res_ty)

-    name = mkPrimOpIdName prim_op
+    name = mkWiredInName gHC_PRIM (primOpOcc prim_op) 
+                        (mkPrimOpIdUnique (primOpTag prim_op))
+                        Nothing (AnId id) UserSyntax

     id   = mkGlobalId (PrimOpId prim_op) name ty info
                
     info = noCafIdInfo
     id   = mkGlobalId (PrimOpId prim_op) name ty info
                
     info = noCafIdInfo

@@ -740,17 +740,17 @@ BUT make sure they are *exported* LocalIds (setIdLocalExported) so
 that they aren't discarded by the occurrence analyser.
 
 \begin{code}
 that they aren't discarded by the occurrence analyser.
 
 \begin{code}

-mkDefaultMethodId dm_name ty = mkVanillaGlobal dm_name ty noCafIdInfo
+mkDefaultMethodId dm_name ty = mkExportedLocalId dm_name ty

 
 mkDictFunId :: Name            -- Name to use for the dict fun;
 
 mkDictFunId :: Name            -- Name to use for the dict fun;

-           -> Class 

            -> [TyVar]
            -> [TyVar]

-           -> [Type]

            -> ThetaType
            -> ThetaType

+           -> Class 
+           -> [Type]

            -> Id
 
            -> Id
 

-mkDictFunId dfun_name clas inst_tyvars inst_tys dfun_theta
-  = mkVanillaGlobal dfun_name dfun_ty noCafIdInfo
+mkDictFunId dfun_name inst_tyvars dfun_theta clas inst_tys
+  = mkExportedLocalId dfun_name dfun_ty

   where
     dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
 
   where
     dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
 

@@ -806,6 +806,29 @@ they can unify with both unlifted and lifted types.  Hence we provide
 another gun with which to shoot yourself in the foot.
 
 \begin{code}
 another gun with which to shoot yourself in the foot.
 
 \begin{code}

+mkWiredInIdName mod fs uniq id
+ = mkWiredInName mod (mkOccFS varName fs) uniq Nothing (AnId id) UserSyntax
+
+unsafeCoerceName = mkWiredInIdName gHC_PRIM FSLIT("unsafeCoerce#") unsafeCoerceIdKey  unsafeCoerceId
+nullAddrName     = mkWiredInIdName gHC_PRIM FSLIT("nullAddr#")    nullAddrIdKey      nullAddrId
+seqName                 = mkWiredInIdName gHC_PRIM FSLIT("seq")           seqIdKey           seqId
+realWorldName   = mkWiredInIdName gHC_PRIM FSLIT("realWorld#")    realWorldPrimIdKey realWorldPrimId
+lazyIdName      = mkWiredInIdName pREL_BASE FSLIT("lazy")         lazyIdKey          lazyId
+
+errorName               = mkWiredInIdName pREL_ERR FSLIT("error")           errorIdKey eRROR_ID
+recSelErrorName                 = mkWiredInIdName pREL_ERR FSLIT("recSelError")     recSelErrorIdKey rEC_SEL_ERROR_ID
+runtimeErrorName        = mkWiredInIdName pREL_ERR FSLIT("runtimeError")    runtimeErrorIdKey rUNTIME_ERROR_ID
+irrefutPatErrorName     = mkWiredInIdName pREL_ERR FSLIT("irrefutPatError") irrefutPatErrorIdKey iRREFUT_PAT_ERROR_ID
+recConErrorName                 = mkWiredInIdName pREL_ERR FSLIT("recConError")     recConErrorIdKey rEC_CON_ERROR_ID
+patErrorName            = mkWiredInIdName pREL_ERR FSLIT("patError")        patErrorIdKey pAT_ERROR_ID
+noMethodBindingErrorName = mkWiredInIdName pREL_ERR FSLIT("noMethodBindingError")
+                                          noMethodBindingErrorIdKey nO_METHOD_BINDING_ERROR_ID
+nonExhaustiveGuardsErrorName 
+  = mkWiredInIdName pREL_ERR FSLIT("nonExhaustiveGuardsError") 
+                   nonExhaustiveGuardsErrorIdKey nON_EXHAUSTIVE_GUARDS_ERROR_ID
+\end{code}
+
+\begin{code}

 -- unsafeCoerce# :: forall a b. a -> b
 unsafeCoerceId
   = pcMiscPrelId unsafeCoerceName ty info
 -- unsafeCoerce# :: forall a b. a -> b
 unsafeCoerceId
   = pcMiscPrelId unsafeCoerceName ty info

@@ -834,10 +857,10 @@ seqId
     info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
           
 
     info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
           
 

-    ty  = mkForAllTys [alphaTyVar,betaTyVar]
-                     (mkFunTy alphaTy (mkFunTy betaTy betaTy))
-    [x,y] = mkTemplateLocals [alphaTy, betaTy]
-    rhs = mkLams [alphaTyVar,betaTyVar,x,y] (Case (Var x) x [(DEFAULT, [], Var y)])
+    ty  = mkForAllTys [alphaTyVar,openBetaTyVar]
+                     (mkFunTy alphaTy (mkFunTy openBetaTy openBetaTy))
+    [x,y] = mkTemplateLocals [alphaTy, openBetaTy]
+    rhs = mkLams [alphaTyVar,openBetaTyVar,x,y] (Case (Var x) x [(DEFAULT, [], Var y)])

 
 -- lazy :: forall a?. a? -> a?  (i.e. works for unboxed types too)
 -- Used to lazify pseq:                pseq a b = a `seq` lazy b
 
 -- lazy :: forall a?. a? -> a?  (i.e. works for unboxed types too)
 -- Used to lazify pseq:                pseq a b = a `seq` lazy b

@@ -857,24 +880,6 @@ lazyIdUnfolding = mkLams [openAlphaTyVar,x] (Var x)
                  [x] = mkTemplateLocals [openAlphaTy]
 \end{code}
 
                  [x] = mkTemplateLocals [openAlphaTy]
 \end{code}
 

-@getTag#@ is another function which can't be defined in Haskell.  It needs to
-evaluate its argument and call the dataToTag# primitive.
-
-\begin{code}
-getTagId
-  = pcMiscPrelId getTagName ty info
-  where
-    info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
-       -- We don't provide a defn for this; you must inline it
-
-    ty = mkForAllTys [alphaTyVar] (mkFunTy alphaTy intPrimTy)
-    [x,y] = mkTemplateLocals [alphaTy,alphaTy]
-    rhs = mkLams [alphaTyVar,x] $
-         Case (Var x) y [ (DEFAULT, [], mkApps (Var dataToTagId) [Type alphaTy, Var y]) ]
-
-dataToTagId = mkPrimOpId DataToTagOp
-\end{code}
-

 @realWorld#@ used to be a magic literal, \tr{void#}.  If things get
 nasty as-is, change it back to a literal (@Literal@).
 
 @realWorld#@ used to be a magic literal, \tr{void#}.  If things get
 nasty as-is, change it back to a literal (@Literal@).
 

@@ -937,9 +942,9 @@ rEC_SEL_ERROR_ID            = mkRuntimeErrorId recSelErrorName
 rUNTIME_ERROR_ID               = mkRuntimeErrorId runtimeErrorName
 iRREFUT_PAT_ERROR_ID           = mkRuntimeErrorId irrefutPatErrorName
 rEC_CON_ERROR_ID               = mkRuntimeErrorId recConErrorName
 rUNTIME_ERROR_ID               = mkRuntimeErrorId runtimeErrorName
 iRREFUT_PAT_ERROR_ID           = mkRuntimeErrorId irrefutPatErrorName
 rEC_CON_ERROR_ID               = mkRuntimeErrorId recConErrorName

-nON_EXHAUSTIVE_GUARDS_ERROR_ID = mkRuntimeErrorId nonExhaustiveGuardsErrorName

 pAT_ERROR_ID                   = mkRuntimeErrorId patErrorName
 nO_METHOD_BINDING_ERROR_ID      = mkRuntimeErrorId noMethodBindingErrorName
 pAT_ERROR_ID                   = mkRuntimeErrorId patErrorName
 nO_METHOD_BINDING_ERROR_ID      = mkRuntimeErrorId noMethodBindingErrorName

+nON_EXHAUSTIVE_GUARDS_ERROR_ID = mkRuntimeErrorId nonExhaustiveGuardsErrorName

 
 -- The runtime error Ids take a UTF8-encoded string as argument
 mkRuntimeErrorId name = pc_bottoming_Id name runtimeErrorTy
 
 -- The runtime error Ids take a UTF8-encoded string as argument
 mkRuntimeErrorId name = pc_bottoming_Id name runtimeErrorTy

@@ -976,7 +981,7 @@ pcMiscPrelId name ty info
 pc_bottoming_Id name ty
  = pcMiscPrelId name ty bottoming_info
  where
 pc_bottoming_Id name ty
  = pcMiscPrelId name ty bottoming_info
  where

-    bottoming_info = hasCafIdInfo `setAllStrictnessInfo` Just strict_sig
+    bottoming_info = vanillaIdInfo `setAllStrictnessInfo` Just strict_sig

        -- Do *not* mark them as NoCafRefs, because they can indeed have
        -- CAF refs.  For example, pAT_ERROR_ID calls GHC.Err.untangle,
        -- which has some CAFs
        -- Do *not* mark them as NoCafRefs, because they can indeed have
        -- CAF refs.  For example, pAT_ERROR_ID calls GHC.Err.untangle,
        -- which has some CAFs