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% (c) The AQUA Project, Glasgow University, 1993-1998
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\section[SimplMonad]{The simplifier Monad}
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getDOptsSmpl, getSimplRules, getFamEnvs,
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MonadUnique(..), newId,
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SimplCount, tick, freeTick,
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getSimplCount, zeroSimplCount, pprSimplCount,
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plusSimplCount, isZeroSimplCount,
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SwitchChecker, SwitchResult(..), getSimplIntSwitch,
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isAmongSimpl, intSwitchSet, switchIsOn, allOffSwitchChecker
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import Id ( Id, mkSysLocal )
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import FamInstEnv ( FamInstEnv )
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import Rules ( RuleBase )
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import DynFlags ( DynFlags )
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import Maybes ( expectJust )
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import Data.Array.Base (unsafeAt)
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%************************************************************************
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\subsection{Monad plumbing}
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%************************************************************************
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For the simplifier monad, we want to {\em thread} a unique supply and a counter.
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(Command-line switches move around through the explicitly-passed SimplEnv.)
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= SM { unSM :: SimplTopEnv -- Envt that does not change much
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-> UniqSupply -- We thread the unique supply because
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-- constantly splitting it is rather expensive
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-> (result, UniqSupply, SimplCount)}
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data SimplTopEnv = STE { st_flags :: DynFlags
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, st_rules :: RuleBase
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, st_fams :: (FamInstEnv, FamInstEnv) }
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initSmpl :: DynFlags -> RuleBase -> (FamInstEnv, FamInstEnv)
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-> UniqSupply -- No init count; set to 0
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initSmpl dflags rules fam_envs us m
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= case unSM m env us (zeroSimplCount dflags) of
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(result, _, count) -> (result, count)
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env = STE { st_flags = dflags, st_rules = rules, st_fams = fam_envs }
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{-# INLINE thenSmpl #-}
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{-# INLINE thenSmpl_ #-}
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{-# INLINE returnSmpl #-}
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instance Monad SimplM where
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returnSmpl :: a -> SimplM a
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returnSmpl e = SM (\_st_env us sc -> (e, us, sc))
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thenSmpl :: SimplM a -> (a -> SimplM b) -> SimplM b
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thenSmpl_ :: SimplM a -> SimplM b -> SimplM b
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= SM (\ st_env us0 sc0 ->
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case (unSM m st_env us0 sc0) of
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(m_result, us1, sc1) -> unSM (k m_result) st_env us1 sc1 )
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= SM (\st_env us0 sc0 ->
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case (unSM m st_env us0 sc0) of
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(_, us1, sc1) -> unSM k st_env us1 sc1)
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-- TODO: this specializing is not allowed
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-- {-# SPECIALIZE mapM :: (a -> SimplM b) -> [a] -> SimplM [b] #-}
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-- {-# SPECIALIZE mapAndUnzipM :: (a -> SimplM (b, c)) -> [a] -> SimplM ([b],[c]) #-}
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-- {-# SPECIALIZE mapAccumLM :: (acc -> b -> SimplM (acc,c)) -> acc -> [b] -> SimplM (acc, [c]) #-}
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%************************************************************************
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\subsection{The unique supply}
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%************************************************************************
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instance MonadUnique SimplM where
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= SM (\_st_env us sc -> case splitUniqSupply us of
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(us1, us2) -> (us1, us2, sc))
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= SM (\_st_env us sc -> case splitUniqSupply us of
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(us1, us2) -> (uniqFromSupply us1, us2, sc))
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= SM (\_st_env us sc -> case splitUniqSupply us of
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(us1, us2) -> (uniqsFromSupply us1, us2, sc))
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getDOptsSmpl :: SimplM DynFlags
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getDOptsSmpl = SM (\st_env us sc -> (st_flags st_env, us, sc))
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getSimplRules :: SimplM RuleBase
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getSimplRules = SM (\st_env us sc -> (st_rules st_env, us, sc))
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getFamEnvs :: SimplM (FamInstEnv, FamInstEnv)
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getFamEnvs = SM (\st_env us sc -> (st_fams st_env, us, sc))
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newId :: FastString -> Type -> SimplM Id
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newId fs ty = do uniq <- getUniqueM
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return (mkSysLocal fs uniq ty)
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%************************************************************************
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\subsection{Counting up what we've done}
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%************************************************************************
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getSimplCount :: SimplM SimplCount
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getSimplCount = SM (\_st_env us sc -> (sc, us, sc))
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tick :: Tick -> SimplM ()
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= SM (\_st_env us sc -> let sc' = doSimplTick t sc
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in sc' `seq` ((), us, sc'))
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freeTick :: Tick -> SimplM ()
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-- Record a tick, but don't add to the total tick count, which is
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-- used to decide when nothing further has happened
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= SM (\_st_env us sc -> let sc' = doFreeSimplTick t sc
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in sc' `seq` ((), us, sc'))
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%************************************************************************
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\subsubsection{Command-line switches}
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%************************************************************************
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type SwitchChecker = SimplifierSwitch -> SwitchResult
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= SwBool Bool -- on/off
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| SwString FastString -- nothing or a String
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| SwInt Int -- nothing or an Int
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allOffSwitchChecker :: SwitchChecker
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allOffSwitchChecker _ = SwBool False
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isAmongSimpl :: [SimplifierSwitch] -> SimplifierSwitch -> SwitchResult
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isAmongSimpl on_switches -- Switches mentioned later occur *earlier*
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-- in the list; defaults right at the end.
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tidied_on_switches = foldl rm_dups [] on_switches
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-- The fold*l* ensures that we keep the latest switches;
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-- ie the ones that occur earliest in the list.
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sw_tbl :: Array Int SwitchResult
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sw_tbl = (array (0, lAST_SIMPL_SWITCH_TAG) -- bounds...
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all_undefined = [ (i, SwBool False) | i <- [0 .. lAST_SIMPL_SWITCH_TAG ] ]
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defined_elems = map mk_assoc_elem tidied_on_switches
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-- (avoid some unboxing, bounds checking, and other horrible things:)
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\ switch -> unsafeAt sw_tbl $ iBox (tagOf_SimplSwitch switch)
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= (iBox (tagOf_SimplSwitch k), SwBool True) -- I'm here, Mom!
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-- cannot have duplicates if we are going to use the array thing
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rm_dups switches_so_far switch
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= if switch `is_elem` switches_so_far
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else switch : switches_so_far
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_ `is_elem` [] = False
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sw `is_elem` (s:ss) = (tagOf_SimplSwitch sw) ==# (tagOf_SimplSwitch s)
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getSimplIntSwitch :: SwitchChecker -> (Int-> SimplifierSwitch) -> Int
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getSimplIntSwitch chkr switch
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= expectJust "getSimplIntSwitch" (intSwitchSet chkr switch)
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switchIsOn :: (switch -> SwitchResult) -> switch -> Bool
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switchIsOn lookup_fn switch
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= case (lookup_fn switch) of
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SwBool False -> False
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intSwitchSet :: (switch -> SwitchResult)
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intSwitchSet lookup_fn switch
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= case (lookup_fn (switch (panic "intSwitchSet"))) of
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SwInt int -> Just int
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These things behave just like enumeration types.
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instance Eq SimplifierSwitch where
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a == b = tagOf_SimplSwitch a ==# tagOf_SimplSwitch b
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instance Ord SimplifierSwitch where
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a < b = tagOf_SimplSwitch a <# tagOf_SimplSwitch b
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a <= b = tagOf_SimplSwitch a <=# tagOf_SimplSwitch b
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tagOf_SimplSwitch :: SimplifierSwitch -> FastInt
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tagOf_SimplSwitch NoCaseOfCase = _ILIT(1)
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-- If you add anything here, be sure to change lAST_SIMPL_SWITCH_TAG, too!
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lAST_SIMPL_SWITCH_TAG :: Int
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lAST_SIMPL_SWITCH_TAG = 2