--- /dev/null
+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
+%
+%************************************************************************
+%* *
+\section[SATMonad]{The Static Argument Transformation pass Monad}
+%* *
+%************************************************************************
+
+96/03: We aren't using the static-argument transformation right now.
+
+\begin{code}
+module SATMonad where
+
+#include "HsVersions.h"
+
+import Panic ( panic )
+
+junk_from_SATMonad = panic "SATMonad.junk"
+
+{- LATER: to end of file:
+
+module SATMonad (
+ SATInfo(..), updSAEnv,
+ SatM(..), initSAT, emptyEnvSAT,
+ returnSAT, thenSAT, thenSAT_, mapSAT, getSATInfo, newSATName,
+ getArgLists, Arg(..), insSAEnv, saTransform,
+
+ SATEnv(..), isStatic, dropStatics
+ ) where
+
+import Type ( mkTyVarTy, mkSigmaTy,
+ splitSigmaTy, splitFunTys,
+ glueTyArgs, substTy,
+ InstTyEnv(..)
+ )
+import MkId ( mkSysLocal )
+import Id ( idType, idName, mkLocalId )
+import UniqSupply
+import Util
+
+infixr 9 `thenSAT`, `thenSAT_`
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Static Argument Transformation Environment}
+%* *
+%************************************************************************
+
+\begin{code}
+type SATEnv = IdEnv SATInfo
+
+type SATInfo = ([Arg Type],[Arg Id])
+
+data Arg a = Static a | NotStatic
+ deriving Eq
+
+delOneFromSAEnv v us env
+ = ((), delVarEnv env v)
+
+updSAEnv :: Maybe (Id,SATInfo) -> SatM ()
+updSAEnv Nothing
+ = returnSAT ()
+updSAEnv (Just (b,(tyargs,args)))
+ = getSATInfo b `thenSAT` (\ r ->
+ case r of
+ Nothing -> returnSAT ()
+ Just (tyargs',args') -> delOneFromSAEnv b `thenSAT_`
+ insSAEnv b (checkArgs tyargs tyargs',
+ checkArgs args args')
+ )
+
+checkArgs as [] = notStatics (length as)
+checkArgs [] as = notStatics (length as)
+checkArgs (a:as) (a':as') | a == a' = a:checkArgs as as'
+checkArgs (_:as) (_:as') = NotStatic:checkArgs as as'
+
+notStatics :: Int -> [Arg a]
+notStatics n = nOfThem n NotStatic
+
+insSAEnv :: Id -> SATInfo -> SatM ()
+insSAEnv b info us env
+ = ((), extendVarEnv env b info)
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Static Argument Transformation Monad}
+%* *
+%************************************************************************
+
+Two items of state to thread around: a UniqueSupply and a SATEnv.
+
+\begin{code}
+type SatM result
+ = UniqSupply -> SATEnv -> (result, SATEnv)
+
+initSAT :: SatM a -> UniqSupply -> a
+
+initSAT f us = fst (f us emptyVarEnv)
+
+thenSAT m k us env
+ = case splitUniqSupply us of { (s1, s2) ->
+ case m s1 env of { (m_result, menv) ->
+ k m_result s2 menv }}
+
+thenSAT_ m k us env
+ = case splitUniqSupply us of { (s1, s2) ->
+ case m s1 env of { (_, menv) ->
+ k s2 menv }}
+
+emptyEnvSAT :: SatM ()
+emptyEnvSAT us _ = ((), emptyVarEnv)
+
+returnSAT v us env = (v, env)
+
+mapSAT f [] = returnSAT []
+mapSAT f (x:xs)
+ = f x `thenSAT` \ x' ->
+ mapSAT f xs `thenSAT` \ xs' ->
+ returnSAT (x':xs')
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Utility Functions}
+%* *
+%************************************************************************
+
+\begin{code}
+getSATInfo :: Id -> SatM (Maybe SATInfo)
+getSATInfo var us env
+ = (lookupVarEnv env var, env)
+
+newSATName :: Id -> Type -> SatM Id
+newSATName id ty us env
+ = case (getUnique us) of { unique ->
+ let
+ new_name = mkCompoundName SLIT("$sat") unique (idName id)
+ in
+ (mkLocalId new_name ty, env) }
+
+getArgLists :: CoreExpr -> ([Arg Type],[Arg Id])
+getArgLists expr
+ = let
+ (tvs, lambda_bounds, body) = collectBinders expr
+ in
+ ([ Static (mkTyVarTy tv) | tv <- tvs ],
+ [ Static v | v <- lambda_bounds ])
+
+dropArgs :: CoreExpr -> CoreExpr
+dropArgs (Lam _ e) = dropArgs e
+dropArgs (CoTyLam _ e) = dropArgs e
+dropArgs e = e
+\end{code}
+
+We implement saTransform using shadowing of binders, that is
+we transform
+map = \f as -> case as of
+ [] -> []
+ (a':as') -> let x = f a'
+ y = map f as'
+ in x:y
+to
+map = \f as -> let map = \f as -> map' as
+ in let rec map' = \as -> case as of
+ [] -> []
+ (a':as') -> let x = f a'
+ y = map f as'
+ in x:y
+ in map' as
+
+the inner map should get inlined and eliminated.
+\begin{code}
+saTransform :: Id -> CoreExpr -> SatM CoreBinding
+saTransform binder rhs
+ = getSATInfo binder `thenSAT` \ r ->
+ case r of
+ -- [Andre] test: do it only if we have more than one static argument.
+ --Just (tyargs,args) | any isStatic args
+ Just (tyargs,args) | (filter isStatic args) `lengthExceeds` 1
+ -> newSATName binder (new_ty tyargs args) `thenSAT` \ binder' ->
+ mkNewRhs binder binder' tyargs args rhs `thenSAT` \ new_rhs ->
+ trace ("SAT "++ show (length (filter isStatic args))) (
+ returnSAT (NonRec binder new_rhs)
+ )
+ _ -> returnSAT (Rec [(binder, rhs)])
+ where
+ mkNewRhs binder binder' tyargs args rhs
+ = let
+ non_static_args :: [Id]
+ non_static_args
+ = get_nsa args (snd (getArgLists rhs))
+ where
+ get_nsa :: [Arg a] -> [Arg a] -> [a]
+ get_nsa [] _ = []
+ get_nsa _ [] = []
+ get_nsa (NotStatic:args) (Static v:as) = v:get_nsa args as
+ get_nsa (_:args) (_:as) = get_nsa args as
+
+ local_body = foldl App (Var binder')
+ [VarArg a | a <- non_static_args]
+
+ nonrec_rhs = origLams local_body
+
+ -- HACK! The following is a fake SysLocal binder with
+ -- *the same* unique as binder.
+ -- the reason for this is the following:
+ -- this binder *will* get inlined but if it happen to be
+ -- a top level binder it is never removed as dead code,
+ -- therefore we have to remove that information (of it being
+ -- top-level or exported somehow.)
+ -- A better fix is to use binder directly but with the TopLevel
+ -- tag (or Exported tag) modified.
+ fake_binder = mkSysLocal SLIT("sat")
+ (getUnique binder)
+ (idType binder)
+ rec_body = mkValLam non_static_args
+ ( Let (NonRec fake_binder nonrec_rhs)
+ {-in-} (dropArgs rhs))
+ in
+ returnSAT (
+ origLams (Let (Rec [(binder',rec_body)]) {-in-} local_body)
+ )
+ where
+ origLams = origLams' rhs
+ where
+ origLams' (Lam v e) e' = Lam v (origLams' e e')
+ origLams' (CoTyLam ty e) e' = CoTyLam ty (origLams' e e')
+ origLams' _ e' = e'
+
+ new_ty tyargs args
+ = substTy (mk_inst_tyenv tyargs tv_tmpl)
+ (mkSigmaTy tv_tmpl' dict_tys' tau_ty')
+ where
+ -- get type info for the local function:
+ (tv_tmpl, dict_tys, tau_ty) = (splitSigmaTy . idType) binder
+ (reg_arg_tys, res_type) = splitFunTys tau_ty
+
+ -- now, we drop the ones that are
+ -- static, that is, the ones we will not pass to the local function
+ tv_tmpl' = dropStatics tyargs tv_tmpl
+
+ (args1, args2) = splitAtList dict_tys args
+ dict_tys' = dropStatics args1 dict_tys
+ reg_arg_tys' = dropStatics args2 reg_arg_tys
+
+ tau_ty' = glueTyArgs reg_arg_tys' res_type
+
+ mk_inst_tyenv [] _ = emptyVarEnv
+ mk_inst_tyenv (Static s:args) (t:ts) = extendVarEnv (mk_inst_tyenv args ts) t s
+ mk_inst_tyenv (_:args) (_:ts) = mk_inst_tyenv args ts
+
+dropStatics [] t = t
+dropStatics (Static _:args) (t:ts) = dropStatics args ts
+dropStatics (_:args) (t:ts) = t:dropStatics args ts
+
+isStatic :: Arg a -> Bool
+isStatic NotStatic = False
+isStatic _ = True
+-}
+\end{code}
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