X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FsimplCore%2FSimplMonad.lhs;h=903c0fec4def8efeed6bdfce936b8b6b5c49a3f9;hb=5ffba4e2eac0a76ffbe8d98b672fcc39201a591f;hp=1a067b160d49bddcb1fa2d986a521daa16d1ce21;hpb=2c8f04b5b883db74f449dfc8c224929fe28b027d;p=ghc-hetmet.git diff --git a/ghc/compiler/simplCore/SimplMonad.lhs b/ghc/compiler/simplCore/SimplMonad.lhs index 1a067b1..903c0fe 100644 --- a/ghc/compiler/simplCore/SimplMonad.lhs +++ b/ghc/compiler/simplCore/SimplMonad.lhs @@ -1,44 +1,119 @@ % -% (c) The AQUA Project, Glasgow University, 1993-1996 +% (c) The AQUA Project, Glasgow University, 1993-1998 % \section[SimplMonad]{The simplifier Monad} \begin{code} module SimplMonad ( - SmplM, + InId, InBind, InExpr, InAlt, InArg, InType, InBinder, + OutId, OutBind, OutExpr, OutAlt, OutArg, OutType, OutBinder, + OutExprStuff, OutStuff, + + -- The monad + SimplM, initSmpl, returnSmpl, thenSmpl, thenSmpl_, mapSmpl, mapAndUnzipSmpl, mapAccumLSmpl, + -- The inlining black-list + getBlackList, + -- Unique supply getUniqueSmpl, getUniquesSmpl, + newId, newIds, -- Counting - SimplCount{-abstract-}, TickType(..), tick, tickN, tickUnfold, - simplCount, detailedSimplCount, - zeroSimplCount, showSimplCount, combineSimplCounts + SimplCount, Tick(..), + tick, freeTick, + getSimplCount, zeroSimplCount, pprSimplCount, + plusSimplCount, isZeroSimplCount, + + -- Switch checker + SwitchChecker, getSwitchChecker, getSimplIntSwitch, + + -- Cost centres + getEnclosingCC, setEnclosingCC, + + -- Environments + getEnv, setAllExceptInScope, + getSubst, setSubst, + getSubstEnv, extendSubst, extendSubstList, + getInScope, setInScope, extendInScope, extendInScopes, modifyInScope, + setSubstEnv, zapSubstEnv, + getSimplBinderStuff, setSimplBinderStuff, + switchOffInlining ) where #include "HsVersions.h" -import MkId ( mkSysLocal ) -import Id ( mkIdWithNewUniq, Id ) -import SimplEnv -import SrcLoc ( noSrcLoc ) -import TyVar ( TyVar ) -import Type ( Type ) -import UniqSupply ( getUnique, getUniques, splitUniqSupply, +import Id ( Id, mkSysLocal, idUnfolding, isDataConWrapId ) +import IdInfo ( InlinePragInfo(..) ) +import Demand ( Demand ) +import CoreSyn +import CoreUnfold ( isCompulsoryUnfolding, isEvaldUnfolding ) +import PprCore () -- Instances +import Rules ( RuleBase ) +import CostCentre ( CostCentreStack, subsumedCCS ) +import Name ( isLocallyDefined ) +import Var ( TyVar ) +import VarEnv +import VarSet +import qualified Subst +import Subst ( Subst, emptySubst, mkSubst, + substTy, substEnv, + InScopeSet, substInScope, isInScope + ) +import Type ( Type, TyVarSubst, applyTy ) +import UniqSupply ( uniqsFromSupply, uniqFromSupply, splitUniqSupply, UniqSupply ) +import FiniteMap +import CmdLineOpts ( SimplifierSwitch(..), SwitchResult(..), + opt_PprStyle_Debug, opt_HistorySize, + intSwitchSet + ) import Unique ( Unique ) -import Util ( zipWithEqual, Eager, appEager ) +import Maybes ( expectJust ) +import Util ( zipWithEqual ) import Outputable -import Ix -infixr 9 `thenSmpl`, `thenSmpl_` +infixr 0 `thenSmpl`, `thenSmpl_` \end{code} %************************************************************************ %* * +\subsection[Simplify-types]{Type declarations} +%* * +%************************************************************************ + +\begin{code} +type InBinder = CoreBndr +type InId = Id -- Not yet cloned +type InType = Type -- Ditto +type InBind = CoreBind +type InExpr = CoreExpr +type InAlt = CoreAlt +type InArg = CoreArg + +type OutBinder = CoreBndr +type OutId = Id -- Cloned +type OutType = Type -- Cloned +type OutBind = CoreBind +type OutExpr = CoreExpr +type OutAlt = CoreAlt +type OutArg = CoreArg + +type SwitchChecker = SimplifierSwitch -> SwitchResult + +type OutExprStuff = OutStuff (InScopeSet, OutExpr) +type OutStuff a = ([OutBind], a) + -- We return something equivalent to (let b in e), but + -- in pieces to avoid the quadratic blowup when floating + -- incrementally. Comments just before simplExprB in Simplify.lhs +\end{code} + + +%************************************************************************ +%* * \subsection{Monad plumbing} %* * %************************************************************************ @@ -47,41 +122,73 @@ For the simplifier monad, we want to {\em thread} a unique supply and a counter. (Command-line switches move around through the explicitly-passed SimplEnv.) \begin{code} -type SmplM result - = UniqSupply - -> SimplCount -- things being threaded - -> (result, SimplCount) +type SimplM result -- We thread the unique supply because + = SimplEnv -- constantly splitting it is rather expensive + -> UniqSupply + -> SimplCount + -> (result, UniqSupply, SimplCount) + +data SimplEnv + = SimplEnv { + seChkr :: SwitchChecker, + seCC :: CostCentreStack, -- The enclosing CCS (when profiling) + seBlackList :: Id -> Bool, -- True => don't inline this Id + seSubst :: Subst -- The current substitution + } + -- The range of the substitution is OutType and OutExpr resp + -- + -- The substitution is idempotent + -- It *must* be applied; things in its domain simply aren't + -- bound in the result. + -- + -- The substitution usually maps an Id to its clone, + -- but if the orig defn is a let-binding, and + -- the RHS of the let simplifies to an atom, + -- we just add the binding to the substitution and elide the let. + + -- The in-scope part of Subst includes *all* in-scope TyVars and Ids + -- The elements of the set may have better IdInfo than the + -- occurrences of in-scope Ids, and (more important) they will + -- have a correctly-substituted type. So we use a lookup in this + -- set to replace occurrences \end{code} \begin{code} -initSmpl :: UniqSupply -- no init count; set to 0 - -> SmplM a - -> (a, SimplCount) +initSmpl :: SwitchChecker + -> UniqSupply -- No init count; set to 0 + -> VarSet -- In scope (usually empty, but useful for nested calls) + -> (Id -> Bool) -- Black-list function + -> SimplM a + -> (a, SimplCount) + +initSmpl chkr us in_scope black_list m + = case m (emptySimplEnv chkr in_scope black_list) us zeroSimplCount of + (result, _, count) -> (result, count) -initSmpl us m = m us zeroSimplCount {-# INLINE thenSmpl #-} {-# INLINE thenSmpl_ #-} {-# INLINE returnSmpl #-} -returnSmpl :: a -> SmplM a -returnSmpl e us sc = (e, sc) +returnSmpl :: a -> SimplM a +returnSmpl e env us sc = (e, us, sc) + +thenSmpl :: SimplM a -> (a -> SimplM b) -> SimplM b +thenSmpl_ :: SimplM a -> SimplM b -> SimplM b -thenSmpl :: SmplM a -> (a -> SmplM b) -> SmplM b -thenSmpl_ :: SmplM a -> SmplM b -> SmplM b +thenSmpl m k env us0 sc0 + = case (m env us0 sc0) of + (m_result, us1, sc1) -> k m_result env us1 sc1 -thenSmpl m k us sc0 - = case splitUniqSupply us of { (s1, s2) -> - case (m s1 sc0) of { (m_result, sc1) -> - k m_result s2 sc1 }} +thenSmpl_ m k env us0 sc0 + = case (m env us0 sc0) of + (_, us1, sc1) -> k env us1 sc1 +\end{code} -thenSmpl_ m k us sc0 - = case splitUniqSupply us of { (s1, s2) -> - case (m s1 sc0) of { (_, sc1) -> - k s2 sc1 }} -mapSmpl :: (a -> SmplM b) -> [a] -> SmplM [b] -mapAndUnzipSmpl :: (a -> SmplM (b, c)) -> [a] -> SmplM ([b],[c]) +\begin{code} +mapSmpl :: (a -> SimplM b) -> [a] -> SimplM [b] +mapAndUnzipSmpl :: (a -> SimplM (b, c)) -> [a] -> SimplM ([b],[c]) mapSmpl f [] = returnSmpl [] mapSmpl f (x:xs) @@ -99,12 +206,23 @@ mapAccumLSmpl f acc [] = returnSmpl (acc, []) mapAccumLSmpl f acc (x:xs) = f acc x `thenSmpl` \ (acc', x') -> mapAccumLSmpl f acc' xs `thenSmpl` \ (acc'', xs') -> returnSmpl (acc'', x':xs') +\end{code} + -getUniqueSmpl :: SmplM Unique -getUniqueSmpl us sc = (getUnique us, sc) +%************************************************************************ +%* * +\subsection{The unique supply} +%* * +%************************************************************************ + +\begin{code} +getUniqueSmpl :: SimplM Unique +getUniqueSmpl env us sc = case splitUniqSupply us of + (us1, us2) -> (uniqFromSupply us1, us2, sc) -getUniquesSmpl :: Int -> SmplM [Unique] -getUniquesSmpl n us sc = (getUniques n us, sc) +getUniquesSmpl :: Int -> SimplM [Unique] +getUniquesSmpl n env us sc = case splitUniqSupply us of + (us1, us2) -> (uniqsFromSupply n us1, us2, sc) \end{code} @@ -114,230 +232,468 @@ getUniquesSmpl n us sc = (getUniques n us, sc) %* * %************************************************************************ -The assoc list isn't particularly costly, because we only use -the number of ticks in ``real life.'' +\begin{code} +getSimplCount :: SimplM SimplCount +getSimplCount env us sc = (sc, us, sc) + +tick :: Tick -> SimplM () +tick t env us sc = sc' `seq` ((), us, sc') + where + sc' = doTick t sc + +freeTick :: Tick -> SimplM () +-- Record a tick, but don't add to the total tick count, which is +-- used to decide when nothing further has happened +freeTick t env us sc = sc' `seq` ((), us, sc') + where + sc' = doFreeTick t sc +\end{code} -The right thing to do, if you want that to go fast, is thread -a mutable array through @SimplM@. +\begin{code} +verboseSimplStats = opt_PprStyle_Debug -- For now, anyway + +-- Defined both with and without debugging +zeroSimplCount :: SimplCount +isZeroSimplCount :: SimplCount -> Bool +pprSimplCount :: SimplCount -> SDoc +doTick, doFreeTick :: Tick -> SimplCount -> SimplCount +plusSimplCount :: SimplCount -> SimplCount -> SimplCount +\end{code} \begin{code} -data SimplCount - = SimplCount FAST_INT -- number of ticks - [(TickType, Int)] -- assoc list of all diff kinds of ticks - UnfoldingHistory - -type UnfoldingHistory = (Int, -- N - [(Id,Int)], -- Last N unfoldings - [(Id,Int)]) -- The MaxUnfoldHistory unfoldings before that - -data TickType - = UnfoldingDone | MagicUnfold | ConReused - | CaseFloatFromLet | CaseOfCase - | LetFloatFromLet | LetFloatFromCase - | KnownBranch | Let2Case - | CaseMerge | CaseElim - | CaseIdentity - | AtomicRhs -- Rhs of a let-expression was an atom - | EtaExpansion - | CaseOfError - | TyBetaReduction - | BetaReduction - | SpecialisationDone - {- BEGIN F/B ENTRIES -} - -- the 8 rules - | FoldrBuild -- foldr f z (build g) ==> - | FoldrAugment -- foldr f z (augment g z) ==> - | Foldr_Nil -- foldr f z [] ==> - | Foldr_List -- foldr f z (x:...) ==> - - | FoldlBuild -- foldl f z (build g) ==> - | FoldlAugment -- foldl f z (augment g z) ==> - | Foldl_Nil -- foldl f z [] ==> - | Foldl_List -- foldl f z (x:...) ==> - - | Foldr_Cons_Nil -- foldr (:) [] => id - | Foldr_Cons -- foldr (:) => flip (++) - - | Str_FoldrStr -- foldr f z "hello" => unpackFoldrPS__ f z "hello" - | Str_UnpackCons -- unpackFoldrPS# (:) z "hello" => unpackAppendPS__ z "hello" - | Str_UnpackNil -- unpackAppendPS__ [] "hello" => "hello" - {- END F/B ENTRIES -} - deriving (Eq, Ord, Ix) - -instance Text TickType where - showsPrec p UnfoldingDone = showString "UnfoldingDone " - showsPrec p MagicUnfold = showString "MagicUnfold " - showsPrec p ConReused = showString "ConReused " - showsPrec p CaseFloatFromLet= showString "CaseFloatFromLet " - showsPrec p CaseOfCase = showString "CaseOfCase " - showsPrec p LetFloatFromLet = showString "LetFloatFromLet " - showsPrec p LetFloatFromCase= showString "LetFloatFromCase " - showsPrec p KnownBranch = showString "KnownBranch " - showsPrec p Let2Case = showString "Let2Case " - showsPrec p CaseMerge = showString "CaseMerge " - showsPrec p CaseElim = showString "CaseElim " - showsPrec p CaseIdentity = showString "CaseIdentity " - showsPrec p AtomicRhs = showString "AtomicRhs " - showsPrec p EtaExpansion = showString "EtaExpansion " - showsPrec p CaseOfError = showString "CaseOfError " - showsPrec p TyBetaReduction = showString "TyBetaReduction " - showsPrec p BetaReduction = showString "BetaReduction " - showsPrec p SpecialisationDone - = showString "Specialisation " - - -- Foldr/Build Stuff: - showsPrec p FoldrBuild = showString "FoldrBuild " - showsPrec p FoldrAugment = showString "FoldrAugment " - showsPrec p Foldr_Nil = showString "Foldr_Nil " - showsPrec p Foldr_List = showString "Foldr_List " - - showsPrec p FoldlBuild = showString "FoldlBuild " - showsPrec p FoldlAugment = showString "FoldlAugment " - showsPrec p Foldl_Nil = showString "Foldl_Nil " - showsPrec p Foldl_List = showString "Foldl_List " - - showsPrec p Foldr_Cons_Nil = showString "Foldr_Cons_Nil " - showsPrec p Foldr_Cons = showString "Foldr_Cons " - - showsPrec p Str_FoldrStr = showString "Str_FoldrStr " - showsPrec p Str_UnpackCons = showString "Str_UnpackCons " - showsPrec p Str_UnpackNil = showString "Str_UnpackNil " - -showSimplCount :: SimplCount -> String - -showSimplCount (SimplCount _ stuff (_, unf1, unf2)) - = shw stuff ++ "\nMost recent unfoldings: " ++ showSDoc (ppr (reverse unf2 ++ reverse unf1)) +#ifndef DEBUG +---------------------------------------------------------- +-- Debugging OFF +---------------------------------------------------------- +type SimplCount = Int + +zeroSimplCount = 0 + +isZeroSimplCount n = n==0 + +doTick t n = n+1 -- Very basic when not debugging +doFreeTick t n = n -- Don't count leaf visits + +pprSimplCount n = ptext SLIT("Total ticks:") <+> int n + +plusSimplCount n m = n+m + +#else +---------------------------------------------------------- +-- Debugging ON +---------------------------------------------------------- + +data SimplCount = SimplCount { + ticks :: !Int, -- Total ticks + details :: !TickCounts, -- How many of each type + n_log :: !Int, -- N + log1 :: [Tick], -- Last N events; <= opt_HistorySize + log2 :: [Tick] -- Last opt_HistorySize events before that + } + +type TickCounts = FiniteMap Tick Int + +zeroSimplCount = SimplCount {ticks = 0, details = emptyFM, + n_log = 0, log1 = [], log2 = []} + +isZeroSimplCount sc = ticks sc == 0 + +doFreeTick tick sc@SimplCount { details = dts } + = dts' `seqFM` sc { details = dts' } where - shw [] = "" - shw ((t,n):tns) | n /= 0 = show t ++ ('\t' : show n) ++ ('\n' : shw tns) - | otherwise = shw tns + dts' = dts `addTick` tick + +-- Gross hack to persuade GHC 3.03 to do this important seq +seqFM fm x | isEmptyFM fm = x + | otherwise = x -zeroSimplCount :: SimplCount -zeroSimplCount - = SimplCount ILIT(0) stuff (0, [], []) +doTick tick sc@SimplCount { ticks = tks, details = dts, n_log = nl, log1 = l1, log2 = l2 } + | nl >= opt_HistorySize = sc1 { n_log = 1, log1 = [tick], log2 = l1 } + | otherwise = sc1 { n_log = nl+1, log1 = tick : l1 } + where + sc1 = sc { ticks = tks+1, details = dts `addTick` tick } + +-- Don't use plusFM_C because that's lazy, and we want to +-- be pretty strict here! +addTick :: TickCounts -> Tick -> TickCounts +addTick fm tick = case lookupFM fm tick of + Nothing -> addToFM fm tick 1 + Just n -> n1 `seq` addToFM fm tick n1 + where + n1 = n+1 + +plusSimplCount sc1@(SimplCount { ticks = tks1, details = dts1 }) + sc2@(SimplCount { ticks = tks2, details = dts2 }) + = log_base { ticks = tks1 + tks2, details = plusFM_C (+) dts1 dts2 } where - stuff = - [ (UnfoldingDone, 0), - (MagicUnfold, 0), - (ConReused, 0), - (CaseFloatFromLet, 0), - (CaseOfCase, 0), - (LetFloatFromLet, 0), - (LetFloatFromCase, 0), - (KnownBranch, 0), - (Let2Case, 0), - (CaseMerge, 0), - (CaseElim, 0), - (CaseIdentity, 0), - (AtomicRhs, 0), - (EtaExpansion, 0), - (CaseOfError, 0), - (TyBetaReduction,0), - (BetaReduction,0), - (SpecialisationDone,0), - -- Foldr/Build Stuff: - (FoldrBuild, 0), - (FoldrAugment, 0), - (Foldr_Nil, 0), - (Foldr_List, 0), - (FoldlBuild, 0), - (FoldlAugment, 0), - (Foldl_Nil, 0), - (Foldl_List, 0), - (Foldr_Cons_Nil, 0), - (Foldr_Cons, 0), - - (Str_FoldrStr, 0), - (Str_UnpackCons, 0), - (Str_UnpackNil, 0) ] --- ---= array (con2tag_TickType UnfoldingDone, con2tag_TickType FoldrInline) --- [ i := 0 | i <- indices zeroSimplCount ] + -- A hackish way of getting recent log info + log_base | null (log1 sc2) = sc1 -- Nothing at all in sc2 + | null (log2 sc2) = sc2 { log2 = log1 sc1 } + | otherwise = sc2 + + +pprSimplCount (SimplCount { ticks = tks, details = dts, log1 = l1, log2 = l2 }) + = vcat [ptext SLIT("Total ticks: ") <+> int tks, + text "", + pprTickCounts (fmToList dts), + if verboseSimplStats then + vcat [text "", + ptext SLIT("Log (most recent first)"), + nest 4 (vcat (map ppr l1) $$ vcat (map ppr l2))] + else empty + ] + +pprTickCounts :: [(Tick,Int)] -> SDoc +pprTickCounts [] = empty +pprTickCounts ((tick1,n1):ticks) + = vcat [int tot_n <+> text (tickString tick1), + pprTCDetails real_these, + pprTickCounts others + ] + where + tick1_tag = tickToTag tick1 + (these, others) = span same_tick ticks + real_these = (tick1,n1):these + same_tick (tick2,_) = tickToTag tick2 == tick1_tag + tot_n = sum [n | (_,n) <- real_these] + +pprTCDetails ticks@((tick,_):_) + | verboseSimplStats || isRuleFired tick + = nest 4 (vcat [int n <+> pprTickCts tick | (tick,n) <- ticks]) + | otherwise + = empty +#endif +\end{code} + +%************************************************************************ +%* * +\subsection{Ticks} +%* * +%************************************************************************ + +\begin{code} +data Tick + = PreInlineUnconditionally Id + | PostInlineUnconditionally Id + + | UnfoldingDone Id + | RuleFired FAST_STRING -- Rule name + + | LetFloatFromLet Id -- Thing floated out + | EtaExpansion Id -- LHS binder + | EtaReduction Id -- Binder on outer lambda + | BetaReduction Id -- Lambda binder + + + | CaseOfCase Id -- Bndr on *inner* case + | KnownBranch Id -- Case binder + | CaseMerge Id -- Binder on outer case + | CaseElim Id -- Case binder + | CaseIdentity Id -- Case binder + | FillInCaseDefault Id -- Case binder + + | BottomFound + | SimplifierDone -- Ticked at each iteration of the simplifier + +isRuleFired (RuleFired _) = True +isRuleFired other = False + +instance Outputable Tick where + ppr tick = text (tickString tick) <+> pprTickCts tick + +instance Eq Tick where + a == b = case a `cmpTick` b of { EQ -> True; other -> False } + +instance Ord Tick where + compare = cmpTick + +tickToTag :: Tick -> Int +tickToTag (PreInlineUnconditionally _) = 0 +tickToTag (PostInlineUnconditionally _) = 1 +tickToTag (UnfoldingDone _) = 2 +tickToTag (RuleFired _) = 3 +tickToTag (LetFloatFromLet _) = 4 +tickToTag (EtaExpansion _) = 5 +tickToTag (EtaReduction _) = 6 +tickToTag (BetaReduction _) = 7 +tickToTag (CaseOfCase _) = 8 +tickToTag (KnownBranch _) = 9 +tickToTag (CaseMerge _) = 10 +tickToTag (CaseElim _) = 11 +tickToTag (CaseIdentity _) = 12 +tickToTag (FillInCaseDefault _) = 13 +tickToTag BottomFound = 14 +tickToTag SimplifierDone = 16 + +tickString :: Tick -> String +tickString (PreInlineUnconditionally _) = "PreInlineUnconditionally" +tickString (PostInlineUnconditionally _)= "PostInlineUnconditionally" +tickString (UnfoldingDone _) = "UnfoldingDone" +tickString (RuleFired _) = "RuleFired" +tickString (LetFloatFromLet _) = "LetFloatFromLet" +tickString (EtaExpansion _) = "EtaExpansion" +tickString (EtaReduction _) = "EtaReduction" +tickString (BetaReduction _) = "BetaReduction" +tickString (CaseOfCase _) = "CaseOfCase" +tickString (KnownBranch _) = "KnownBranch" +tickString (CaseMerge _) = "CaseMerge" +tickString (CaseElim _) = "CaseElim" +tickString (CaseIdentity _) = "CaseIdentity" +tickString (FillInCaseDefault _) = "FillInCaseDefault" +tickString BottomFound = "BottomFound" +tickString SimplifierDone = "SimplifierDone" + +pprTickCts :: Tick -> SDoc +pprTickCts (PreInlineUnconditionally v) = ppr v +pprTickCts (PostInlineUnconditionally v)= ppr v +pprTickCts (UnfoldingDone v) = ppr v +pprTickCts (RuleFired v) = ppr v +pprTickCts (LetFloatFromLet v) = ppr v +pprTickCts (EtaExpansion v) = ppr v +pprTickCts (EtaReduction v) = ppr v +pprTickCts (BetaReduction v) = ppr v +pprTickCts (CaseOfCase v) = ppr v +pprTickCts (KnownBranch v) = ppr v +pprTickCts (CaseMerge v) = ppr v +pprTickCts (CaseElim v) = ppr v +pprTickCts (CaseIdentity v) = ppr v +pprTickCts (FillInCaseDefault v) = ppr v +pprTickCts other = empty + +cmpTick :: Tick -> Tick -> Ordering +cmpTick a b = case (tickToTag a `compare` tickToTag b) of + GT -> GT + EQ | isRuleFired a || verboseSimplStats -> cmpEqTick a b + | otherwise -> EQ + LT -> LT + -- Always distinguish RuleFired, so that the stats + -- can report them even in non-verbose mode + +cmpEqTick :: Tick -> Tick -> Ordering +cmpEqTick (PreInlineUnconditionally a) (PreInlineUnconditionally b) = a `compare` b +cmpEqTick (PostInlineUnconditionally a) (PostInlineUnconditionally b) = a `compare` b +cmpEqTick (UnfoldingDone a) (UnfoldingDone b) = a `compare` b +cmpEqTick (RuleFired a) (RuleFired b) = a `compare` b +cmpEqTick (LetFloatFromLet a) (LetFloatFromLet b) = a `compare` b +cmpEqTick (EtaExpansion a) (EtaExpansion b) = a `compare` b +cmpEqTick (EtaReduction a) (EtaReduction b) = a `compare` b +cmpEqTick (BetaReduction a) (BetaReduction b) = a `compare` b +cmpEqTick (CaseOfCase a) (CaseOfCase b) = a `compare` b +cmpEqTick (KnownBranch a) (KnownBranch b) = a `compare` b +cmpEqTick (CaseMerge a) (CaseMerge b) = a `compare` b +cmpEqTick (CaseElim a) (CaseElim b) = a `compare` b +cmpEqTick (CaseIdentity a) (CaseIdentity b) = a `compare` b +cmpEqTick (FillInCaseDefault a) (FillInCaseDefault b) = a `compare` b +cmpEqTick other1 other2 = EQ \end{code} -Counting-related monad functions: + +%************************************************************************ +%* * +\subsubsection{Command-line switches} +%* * +%************************************************************************ + \begin{code} -tick :: TickType -> SmplM () +getSwitchChecker :: SimplM SwitchChecker +getSwitchChecker env us sc = (seChkr env, us, sc) + +getSimplIntSwitch :: SwitchChecker -> (Int-> SimplifierSwitch) -> Int +getSimplIntSwitch chkr switch + = expectJust "getSimplIntSwitch" (intSwitchSet chkr switch) +\end{code} -tick tick_type us (SimplCount n stuff unf) - = -- pprTrace "Tick: " (text (show tick_type)) $ -#ifdef OMIT_SIMPL_COUNTS - ((), SimplCount (n _ADD_ ILIT(1) stuff unf)) stuff -- don't change anything -#else - new_stuff `seqL` - ((), SimplCount (n _ADD_ ILIT(1)) new_stuff unf) - where - new_stuff = inc_tick tick_type ILIT(1) stuff -#endif -maxUnfoldHistory :: Int -maxUnfoldHistory = 20 +@switchOffInlining@ is used to prepare the environment for simplifying +the RHS of an Id that's marked with an INLINE pragma. It is going to +be inlined wherever they are used, and then all the inlining will take +effect. Meanwhile, there isn't much point in doing anything to the +as-yet-un-INLINEd rhs. Furthremore, it's very important to switch off +inlining! because + (a) not doing so will inline a worker straight back into its wrapper! + +and (b) Consider the following example + let f = \pq -> BIG + in + let g = \y -> f y y + {-# INLINE g #-} + in ...g...g...g...g...g... + + Now, if that's the ONLY occurrence of f, it will be inlined inside g, + and thence copied multiple times when g is inlined. + + Andy disagrees! Example: + all xs = foldr (&&) True xs + any p = all . map p {-# INLINE any #-} + + Problem: any won't get deforested, and so if it's exported and + the importer doesn't use the inlining, (eg passes it as an arg) + then we won't get deforestation at all. + We havn't solved this problem yet! + +We prepare the envt by simply modifying the in_scope_env, which has all the +unfolding info. At one point we did it by modifying the chkr so that +it said "EssentialUnfoldingsOnly", but that prevented legitmate, and +important, simplifications happening in the body of the RHS. + +6/98 update: + +We *don't* prevent inlining from happening for identifiers +that are marked as IMustBeINLINEd. An example of where +doing this is crucial is: + + class Bar a => Foo a where + ...g.... + {-# INLINE f #-} + f :: Foo a => a -> b + f x = ....Foo_sc1... + +If `f' needs to peer inside Foo's superclass, Bar, it refers +to the appropriate super class selector, which is marked as +must-inlineable. We don't generate any code for a superclass +selector, so failing to inline it in the RHS of `f' will +leave a reference to a non-existent id, with bad consequences. + +ALSO NOTE that we do all this by modifing the inline-pragma, +not by zapping the unfolding. The latter may still be useful for +knowing when something is evaluated. + +June 98 update: I've gone back to dealing with this by adding +the EssentialUnfoldingsOnly switch. That doesn't stop essential +unfoldings, nor inlineUnconditionally stuff; and the thing's going +to be inlined at every call site anyway. Running over the whole +environment seems like wild overkill. -tickUnfold :: Id -> SmplM () -tickUnfold id us (SimplCount n stuff (n_unf, unf1, unf2)) - = -- pprTrace "Unfolding: " (ppr id) $ - new_stuff `seqL` - new_unf `seqTriple` - ((), SimplCount (n _ADD_ ILIT(1)) new_stuff new_unf) +\begin{code} +switchOffInlining :: SimplM a -> SimplM a +switchOffInlining m env us sc + = m (env { seBlackList = \v -> not (isCompulsoryUnfolding (idUnfolding v)) && + not (isDataConWrapId v) && + ((v `isInScope` subst) || not (isLocallyDefined v)) + }) us sc + + -- Inside inlinings, black list anything that is in scope or imported. + -- except for things that must be unfolded (Compulsory) + -- and data con wrappers. The latter is a hack, like the one in + -- SimplCore.simplRules, to make wrappers inline in rule LHSs. We + -- may as well do the same here. where - new_stuff = inc_tick UnfoldingDone ILIT(1) stuff + subst = seSubst env + old_black_list = seBlackList env +\end{code} - new_unf | n_unf >= maxUnfoldHistory = (1, [unf_item], unf1) - | otherwise = (n_unf+1, unf_item:unf1, unf2) - - unf_item = (id, IBOX(n)) +%************************************************************************ +%* * +\subsubsection{The ``enclosing cost-centre''} +%* * +%************************************************************************ - -- force list to avoid getting a chain of @inc_tick@ applications - -- building up on the heap. (Only true when not dumping stats). -seqL [] y = y -seqL (_:_) y = y +\begin{code} +getEnclosingCC :: SimplM CostCentreStack +getEnclosingCC env us sc = (seCC env, us, sc) -seqTriple (_,_,_) y = y +setEnclosingCC :: CostCentreStack -> SimplM a -> SimplM a +setEnclosingCC cc m env us sc = m (env { seCC = cc }) us sc +\end{code} -tickN :: TickType -> Int -> SmplM () -tickN tick_type 0 us counts - = ((), counts) -tickN tick_type IBOX(increment) us (SimplCount n stuff unf) - = -- pprTrace "Tick: " (text (show tick_type)) $ -#ifdef OMIT_SIMPL_COUNTS - ((), SimplCount (n _ADD_ increment) stuff) -- don't change anything -#else - new_stuff `seqL` - ((), SimplCount (n _ADD_ increment) new_stuff unf) - where - new_stuff = inc_tick tick_type increment stuff +%************************************************************************ +%* * +\subsubsection{The @SimplEnv@ type} +%* * +%************************************************************************ -inc_tick tick_type n [] = panic "couldn't inc_tick!" +\begin{code} +emptySimplEnv :: SwitchChecker -> InScopeSet -> (Id -> Bool) -> SimplEnv -inc_tick tick_type n (x@(ttype, I# cnt#) : xs) - | ttype == tick_type = case cnt# +# n of - incd -> (ttype,IBOX(incd)) : xs +emptySimplEnv sw_chkr in_scope black_list + = SimplEnv { seChkr = sw_chkr, seCC = subsumedCCS, + seBlackList = black_list, + seSubst = mkSubst in_scope emptySubstEnv } + -- The top level "enclosing CC" is "SUBSUMED". - | otherwise = case inc_tick tick_type n xs of { [] -> [x]; ls -> x:ls } -#endif +getEnv :: SimplM SimplEnv +getEnv env us sc = (env, us, sc) -simplCount :: SmplM Int -simplCount us sc@(SimplCount n _ _) = (IBOX(n), sc) +setAllExceptInScope :: SimplEnv -> SimplM a -> SimplM a +setAllExceptInScope new_env@(SimplEnv {seSubst = new_subst}) m + (SimplEnv {seSubst = old_subst}) us sc + = m (new_env {seSubst = Subst.setInScope new_subst (substInScope old_subst)}) us sc -detailedSimplCount :: SmplM SimplCount -detailedSimplCount us sc = (sc, sc) +getSubst :: SimplM Subst +getSubst env us sc = (seSubst env, us, sc) -combineSimplCounts :: SimplCount -> SimplCount -> SimplCount +getBlackList :: SimplM (Id -> Bool) +getBlackList env us sc = (seBlackList env, us, sc) -#ifdef OMIT_SIMPL_COUNTS -combineSimplCounts (SimplCount n1 stuff1 unf1) (SimplCount n2 stuff2 unf2) - = SimplCount (n1 _ADD_ n2) - stuff2 -- just pick one - unf2 -#else -combineSimplCounts (SimplCount n1 stuff1 unf1) (SimplCount n2 stuff2 unf2) - = new_stuff `seqL` - SimplCount (n1 _ADD_ n2) new_stuff unf2 -- Just pick the second for unfold history - where - new_stuff = zipWithEqual "combineSimplCounts" (\ (t1,c1) (t2,c2) -> (t1,c1+c2)) stuff1 stuff2 -#endif +setSubst :: Subst -> SimplM a -> SimplM a +setSubst subst m env us sc = m (env {seSubst = subst}) us sc + +getSubstEnv :: SimplM SubstEnv +getSubstEnv env us sc = (substEnv (seSubst env), us, sc) + +extendInScope :: CoreBndr -> SimplM a -> SimplM a +extendInScope v m env@(SimplEnv {seSubst = subst}) us sc + = m (env {seSubst = Subst.extendInScope subst v}) us sc + +extendInScopes :: [CoreBndr] -> SimplM a -> SimplM a +extendInScopes vs m env@(SimplEnv {seSubst = subst}) us sc + = m (env {seSubst = Subst.extendInScopes subst vs}) us sc + +getInScope :: SimplM InScopeSet +getInScope env us sc = (substInScope (seSubst env), us, sc) + +setInScope :: InScopeSet -> SimplM a -> SimplM a +setInScope in_scope m env@(SimplEnv {seSubst = subst}) us sc + = m (env {seSubst = Subst.setInScope subst in_scope}) us sc + +modifyInScope :: CoreBndr -> CoreBndr -> SimplM a -> SimplM a +modifyInScope v v' m env@(SimplEnv {seSubst = subst}) us sc + = m (env {seSubst = Subst.modifyInScope subst v v'}) us sc + +extendSubst :: CoreBndr -> SubstResult -> SimplM a -> SimplM a +extendSubst var res m env@(SimplEnv {seSubst = subst}) us sc + = m (env { seSubst = Subst.extendSubst subst var res }) us sc + +extendSubstList :: [CoreBndr] -> [SubstResult] -> SimplM a -> SimplM a +extendSubstList vars ress m env@(SimplEnv {seSubst = subst}) us sc + = m (env { seSubst = Subst.extendSubstList subst vars ress }) us sc + +setSubstEnv :: SubstEnv -> SimplM a -> SimplM a +setSubstEnv senv m env@(SimplEnv {seSubst = subst}) us sc + = m (env {seSubst = Subst.setSubstEnv subst senv}) us sc + +zapSubstEnv :: SimplM a -> SimplM a +zapSubstEnv m env@(SimplEnv {seSubst = subst}) us sc + = m (env {seSubst = Subst.zapSubstEnv subst}) us sc + +getSimplBinderStuff :: SimplM (Subst, UniqSupply) +getSimplBinderStuff (SimplEnv {seSubst = subst}) us sc + = ((subst, us), us, sc) + +setSimplBinderStuff :: (Subst, UniqSupply) -> SimplM a -> SimplM a +setSimplBinderStuff (subst, us) m env _ sc + = m (env {seSubst = subst}) us sc \end{code} + +\begin{code} +newId :: Type -> (Id -> SimplM a) -> SimplM a + -- Extends the in-scope-env too +newId ty m env@(SimplEnv {seSubst = subst}) us sc + = case splitUniqSupply us of + (us1, us2) -> m v (env {seSubst = Subst.extendInScope subst v}) us2 sc + where + v = mkSysLocal SLIT("s") (uniqFromSupply us1) ty + +newIds :: [Type] -> ([Id] -> SimplM a) -> SimplM a +newIds tys m env@(SimplEnv {seSubst = subst}) us sc + = case splitUniqSupply us of + (us1, us2) -> m vs (env {seSubst = Subst.extendInScopes subst vs}) us2 sc + where + vs = zipWithEqual "newIds" (mkSysLocal SLIT("s")) + (uniqsFromSupply (length tys) us1) tys + +\end{code}