X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreUnfold.lhs;h=b59e9cf140189d7772f0b2fe7590105b4613de6e;hb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;hp=37eede1e4eec080e2e6cdaab1b7a88a6ed5ff66a;hpb=12899612693163154531da3285ec99c1c8ca2226;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreUnfold.lhs b/ghc/compiler/coreSyn/CoreUnfold.lhs index 37eede1..b59e9cf 100644 --- a/ghc/compiler/coreSyn/CoreUnfold.lhs +++ b/ghc/compiler/coreSyn/CoreUnfold.lhs @@ -1,5 +1,5 @@ % -% (c) The AQUA Project, Glasgow University, 1994-1996 +% (c) The AQUA Project, Glasgow University, 1994-1998 % \section[CoreUnfold]{Core-syntax unfoldings} @@ -9,55 +9,51 @@ syntax (namely @CoreExpr@s). The type @Unfolding@ sits ``above'' simply-Core-expressions unfoldings, capturing ``higher-level'' things we know about a binding, usually things that the simplifier found out (e.g., ``it's a -literal''). In the corner of a @SimpleUnfolding@ unfolding, you will +literal''). In the corner of a @CoreUnfolding@ unfolding, you will find, unsurprisingly, a Core expression. \begin{code} -#include "HsVersions.h" - module CoreUnfold ( - SimpleUnfolding(..), Unfolding(..), UnfoldingGuidance(..), -- types + Unfolding(..), UnfoldingGuidance(..), -- types - FormSummary(..), mkFormSummary, whnfOrBottom, exprSmallEnoughToDup, + noUnfolding, mkMagicUnfolding, mkUnfolding, getUnfoldingTemplate, + isEvaldUnfolding, hasUnfolding, - smallEnoughToInline, couldBeSmallEnoughToInline, + smallEnoughToInline, couldBeSmallEnoughToInline, + certainlySmallEnoughToInline, + okToUnfoldInHiFile, - mkSimpleUnfolding, - mkMagicUnfolding, - calcUnfoldingGuidance, - mentionedInUnfolding + calcUnfoldingGuidance ) where -IMP_Ubiq() -IMPORT_DELOOPER(IdLoop) -- for paranoia checking; - -- and also to get mkMagicUnfoldingFun -IMPORT_DELOOPER(PrelLoop) -- for paranoia checking +#include "HsVersions.h" -import Bag ( emptyBag, unitBag, unionBags, Bag ) -import CgCompInfo ( uNFOLDING_CHEAP_OP_COST, +import {-# SOURCE #-} MagicUFs ( MagicUnfoldingFun, mkMagicUnfoldingFun ) + +import CmdLineOpts ( opt_UnfoldingCreationThreshold, + opt_UnfoldingUseThreshold, + opt_UnfoldingConDiscount, + opt_UnfoldingKeenessFactor, + opt_UnfoldCasms + ) +import Constants ( uNFOLDING_CHEAP_OP_COST, uNFOLDING_DEAR_OP_COST, uNFOLDING_NOREP_LIT_COST ) import CoreSyn -import CoreUtils ( coreExprType ) -import CostCentre ( ccMentionsId ) -import Id ( idType, getIdArity, isBottomingId, - SYN_IE(IdSet), GenId{-instances-} ) -import PrimOp ( fragilePrimOp, PrimOp(..) ) -import IdInfo ( arityMaybe, bottomIsGuaranteed ) -import Literal ( isNoRepLit, isLitLitLit ) -import Pretty -import PrimOp ( primOpCanTriggerGC, PrimOp(..) ) +import OccurAnal ( occurAnalyseGlobalExpr ) +import CoreUtils ( coreExprType, exprIsTrivial, mkFormSummary, + FormSummary(..) ) +import Id ( Id, idType, isId ) +import Const ( Con(..), isLitLitLit ) +import PrimOp ( PrimOp(..), primOpOutOfLine ) +import IdInfo ( ArityInfo(..), InlinePragInfo(..) ) import TyCon ( tyConFamilySize ) -import Type ( getAppDataTyConExpandingDicts ) -import UniqSet ( emptyUniqSet, unitUniqSet, mkUniqSet, - addOneToUniqSet, unionUniqSets - ) -import Usage ( SYN_IE(UVar) ) -import Util ( isIn, panic, assertPanic ) - -whatsMentionedInId = panic "whatsMentionedInId (CoreUnfold)" -getMentionedTyConsAndClassesFromType = panic "getMentionedTyConsAndClassesFromType (CoreUnfold)" +import Type ( splitAlgTyConApp_maybe ) +import Const ( isNoRepLit ) +import Unique ( Unique ) +import Util ( isIn, panic ) +import Outputable \end{code} %************************************************************************ @@ -69,28 +65,52 @@ getMentionedTyConsAndClassesFromType = panic "getMentionedTyConsAndClassesFromTy \begin{code} data Unfolding = NoUnfolding - | CoreUnfolding SimpleUnfolding - | MagicUnfolding - Unique -- of the Id whose magic unfolding this is - MagicUnfoldingFun + | OtherCon [Con] -- It ain't one of these + -- (OtherCon xs) also indicates that something has been evaluated + -- and hence there's no point in re-evaluating it. + -- OtherCon [] is used even for non-data-type values + -- to indicated evaluated-ness. Notably: + -- data C = C !(Int -> Int) + -- case x of { C f -> ... } + -- Here, f gets an OtherCon [] unfolding. -data SimpleUnfolding - = SimpleUnfolding FormSummary -- Tells whether the template is a WHNF or bottom - UnfoldingGuidance -- Tells about the *size* of the template. - TemplateOutExpr -- The template + | CoreUnfolding -- An unfolding with redundant cached information + FormSummary -- Tells whether the template is a WHNF or bottom + UnfoldingGuidance -- Tells about the *size* of the template. + CoreExpr -- Template; binder-info is correct -type TemplateOutExpr = GenCoreExpr (Id, BinderInfo) Id TyVar UVar - -- An OutExpr with occurrence info attached. This is used as - -- a template in GeneralForms. + | MagicUnfolding + Unique -- Unique of the Id whose magic unfolding this is + MagicUnfoldingFun +\end{code} +\begin{code} +noUnfolding = NoUnfolding -mkSimpleUnfolding form guidance template - = SimpleUnfolding form guidance template +mkUnfolding expr + = let + -- strictness mangling (depends on there being no CSE) + ufg = calcUnfoldingGuidance opt_UnfoldingCreationThreshold expr + occ = occurAnalyseGlobalExpr expr + in + CoreUnfolding (mkFormSummary expr) ufg occ mkMagicUnfolding :: Unique -> Unfolding mkMagicUnfolding tag = MagicUnfolding tag (mkMagicUnfoldingFun tag) +getUnfoldingTemplate :: Unfolding -> CoreExpr +getUnfoldingTemplate (CoreUnfolding _ _ expr) = expr +getUnfoldingTemplate other = panic "getUnfoldingTemplate" + +isEvaldUnfolding :: Unfolding -> Bool +isEvaldUnfolding (OtherCon _) = True +isEvaldUnfolding (CoreUnfolding ValueForm _ expr) = True +isEvaldUnfolding other = False + +hasUnfolding :: Unfolding -> Bool +hasUnfolding NoUnfolding = False +hasUnfolding other = True data UnfoldingGuidance = UnfoldNever @@ -101,267 +121,192 @@ data UnfoldingGuidance | UnfoldIfGoodArgs Int -- if "m" type args Int -- and "n" value args + [Int] -- Discount if the argument is evaluated. -- (i.e., a simplification will definitely -- be possible). One elt of the list per *value* arg. + Int -- The "size" of the unfolding; to be elaborated -- later. ToDo + + Int -- Scrutinee discount: the discount to substract if the thing is in + -- a context (case (thing args) of ...), + -- (where there are the right number of arguments.) \end{code} \begin{code} instance Outputable UnfoldingGuidance where - ppr sty UnfoldAlways = ppStr "_ALWAYS_" --- ppr sty EssentialUnfolding = ppStr "_ESSENTIAL_" -- shouldn't appear in an iface - ppr sty (UnfoldIfGoodArgs t v cs size) - = ppCat [ppStr "_IF_ARGS_", ppInt t, ppInt v, + ppr UnfoldAlways = ptext SLIT("_ALWAYS_") + ppr (UnfoldIfGoodArgs t v cs size discount) + = hsep [ptext SLIT("_IF_ARGS_"), int t, int v, if null cs -- always print *something* - then ppChar 'X' - else ppBesides (map (ppStr . show) cs), - ppInt size ] + then char 'X' + else hcat (map (text . show) cs), + int size, + int discount ] \end{code} %************************************************************************ %* * -\subsection{Figuring out things about expressions} -%* * -%************************************************************************ - -\begin{code} -data FormSummary - = VarForm -- Expression is a variable (or scc var, etc) - | ValueForm -- Expression is a value: i.e. a value-lambda,constructor, or literal - | BottomForm -- Expression is guaranteed to be bottom. We're more gung - -- ho about inlining such things, because it can't waste work - | OtherForm -- Anything else - -instance Outputable FormSummary where - ppr sty VarForm = ppStr "Var" - ppr sty ValueForm = ppStr "Value" - ppr sty BottomForm = ppStr "Bot" - ppr sty OtherForm = ppStr "Other" - -mkFormSummary ::GenCoreExpr bndr Id tyvar uvar -> FormSummary - -mkFormSummary expr - = go (0::Int) expr -- The "n" is the number of (value) arguments so far - where - go n (Lit _) = ASSERT(n==0) ValueForm - go n (Con _ _) = ASSERT(n==0) ValueForm - go n (SCC _ e) = go n e - go n (Coerce _ _ e) = go n e - go n (Let _ e) = OtherForm - go n (Case _ _) = OtherForm - - go 0 (Lam (ValBinder x) e) = ValueForm -- NB: \x.bottom /= bottom! - go n (Lam (ValBinder x) e) = go (n-1) e -- Applied lambda - go n (Lam other_binder e) = go n e - - go n (App fun arg) | isValArg arg = go (n+1) fun - go n (App fun other_arg) = go n fun - - go n (Var f) | isBottomingId f = BottomForm - go 0 (Var f) = VarForm - go n (Var f) = case (arityMaybe (getIdArity f)) of - Just arity | n < arity -> ValueForm - other -> OtherForm - -whnfOrBottom :: GenCoreExpr bndr Id tyvar uvar -> Bool -whnfOrBottom e = case mkFormSummary e of - VarForm -> True - ValueForm -> True - BottomForm -> True - OtherForm -> False -\end{code} - - -\begin{code} -exprSmallEnoughToDup (Con _ _) = True -- Could check # of args -exprSmallEnoughToDup (Prim op _) = not (fragilePrimOp op) -- Could check # of args -exprSmallEnoughToDup (Lit lit) = not (isNoRepLit lit) -exprSmallEnoughToDup expr - = case (collectArgs expr) of { (fun, _, _, vargs) -> - case fun of - Var v | length vargs == 0 -> True - _ -> False - } - -{- LATER: -WAS: MORE CLEVER: -exprSmallEnoughToDup expr -- for now, just: applied to - = case (collectArgs expr) of { (fun, _, _, vargs) -> - case fun of - Var v -> v /= buildId - && v /= augmentId - && length vargs <= 6 -- or 10 or 1 or 4 or anything smallish. - _ -> False - } --} -\end{code} -Question (ADR): What is the above used for? Is a _ccall_ really small -enough? - -%************************************************************************ -%* * \subsection[calcUnfoldingGuidance]{Calculate ``unfolding guidance'' for an expression} %* * %************************************************************************ \begin{code} calcUnfoldingGuidance - :: Bool -- True <=> OK if _scc_s appear in expr - -> Int -- bomb out if size gets bigger than this + :: Int -- bomb out if size gets bigger than this -> CoreExpr -- expression to look at -> UnfoldingGuidance - -calcUnfoldingGuidance scc_s_OK bOMB_OUT_SIZE expr - = let - (use_binders, ty_binders, val_binders, body) = collectBinders expr - in - case (sizeExpr scc_s_OK bOMB_OUT_SIZE val_binders body) of - - Nothing -> UnfoldNever - - Just (size, cased_args) - -> let - uf = UnfoldIfGoodArgs +calcUnfoldingGuidance bOMB_OUT_SIZE expr + | exprIsTrivial expr -- Often trivial expressions are never bound + -- to an expression, but it can happen. For + -- example, the Id for a nullary constructor has + -- a trivial expression as its unfolding, and + -- we want to make sure that we always unfold it. + = UnfoldAlways + + | otherwise + = case collectTyAndValBinders expr of { (ty_binders, val_binders, body) -> + case (sizeExpr bOMB_OUT_SIZE val_binders body) of + + TooBig -> UnfoldNever + + SizeIs size cased_args scrut_discount + -> UnfoldIfGoodArgs (length ty_binders) (length val_binders) (map discount_for val_binders) - size - discount_for b | b `is_elem` cased_args = tyConFamilySize tycon - | otherwise = 0 - where - (tycon, _, _) = getAppDataTyConExpandingDicts (idType b) - in - -- pprTrace "calcUnfold:" (ppAbove (ppr PprDebug uf) (ppr PprDebug expr)) - uf - where - is_elem = isIn "calcUnfoldingGuidance" + (I# size) + (I# scrut_discount) + where + discount_for b + | num_cases == 0 = 0 + | otherwise + = if is_data + then tyConFamilySize tycon * num_cases + else num_cases -- prim cases are pretty cheap + + where + (is_data, tycon) + = case (splitAlgTyConApp_maybe (idType b)) of + Nothing -> (False, panic "discount") + Just (tc,_,_) -> (True, tc) + num_cases = length (filter (==b) cased_args) + } \end{code} \begin{code} -sizeExpr :: Bool -- True <=> _scc_s OK - -> Int -- Bomb out if it gets bigger than this +sizeExpr :: Int -- Bomb out if it gets bigger than this -> [Id] -- Arguments; we're interested in which of these -- get case'd -> CoreExpr - -> Maybe (Int, -- Size - [Id] -- Subset of args which are cased - ) + -> ExprSize -sizeExpr scc_s_OK bOMB_OUT_SIZE args expr +sizeExpr (I# bOMB_OUT_SIZE) args expr = size_up expr where + size_up (Type t) = sizeZero -- Types cost nothing + size_up (Note _ body) = size_up body -- Notes cost nothing size_up (Var v) = sizeOne - size_up (App fun arg) = size_up fun `addSize` size_up_arg arg - size_up (Lit lit) = if isNoRepLit lit - then sizeN uNFOLDING_NOREP_LIT_COST - else sizeOne + size_up (App fun arg) = size_up fun `addSize` size_up arg - size_up (SCC _ (Con _ _)) = Nothing -- **** HACK ***** - size_up (SCC lbl body) - = if scc_s_OK then size_up body else Nothing + size_up (Con con args) = foldr (addSize . size_up) + (size_up_con con (valArgCount args)) + args - size_up (Coerce _ _ body) = size_up body -- Coercions cost nothing - - size_up (Con con args) = -- 1 + # of val args - sizeN (1 + numValArgs args) - size_up (Prim op args) = sizeN op_cost -- NB: no charge for PrimOp args - where - op_cost = if primOpCanTriggerGC op - then uNFOLDING_DEAR_OP_COST - -- these *tend* to be more expensive; - -- number chosen to avoid unfolding (HACK) - else uNFOLDING_CHEAP_OP_COST - - size_up expr@(Lam _ _) - = let - (uvars, tyvars, args, body) = collectBinders expr - in - size_up body `addSizeN` length args + size_up (Lam b e) | isId b = size_up e `addSizeN` 1 + | otherwise = size_up e size_up (Let (NonRec binder rhs) body) - = size_up rhs - `addSize` - size_up body - `addSizeN` - 1 + = nukeScrutDiscount (size_up rhs) `addSize` + size_up body `addSizeN` + 1 -- For the allocation size_up (Let (Rec pairs) body) - = foldr addSize sizeZero [size_up rhs | (_,rhs) <- pairs] - `addSize` - size_up body - `addSizeN` - length pairs - - size_up (Case scrut alts) - = size_up_scrut scrut - `addSize` - size_up_alts (coreExprType scrut) alts - -- We charge for the "case" itself in "size_up_alts" - - ------------ - size_up_arg arg = if isValArg arg then sizeOne else sizeZero{-it's free-} - - ------------ - size_up_alts scrut_ty (AlgAlts alts deflt) - = foldr (addSize . size_alg_alt) (size_up_deflt deflt) alts - `addSizeN` (tyConFamilySize tycon) - -- NB: we charge N for an alg. "case", where N is - -- the number of constructors in the thing being eval'd. - -- (You'll eventually get a "discount" of N if you - -- think the "case" is likely to go away.) + = nukeScrutDiscount rhs_size `addSize` + size_up body `addSizeN` + length pairs -- For the allocation where - size_alg_alt (con,args,rhs) = size_up rhs + rhs_size = foldr (addSize . size_up . snd) sizeZero pairs + + size_up (Case scrut _ alts) + = nukeScrutDiscount (size_up scrut) `addSize` + arg_discount scrut `addSize` + foldr (addSize . size_up_alt) sizeZero alts `addSizeN` + case (splitAlgTyConApp_maybe (coreExprType scrut)) of + Nothing -> 1 + Just (tc,_,_) -> tyConFamilySize tc + + ------------ + size_up_alt (con, bndrs, rhs) = size_up rhs -- Don't charge for args, so that wrappers look cheap - (tycon, _, _) = --trace "CoreUnfold.getAppDataTyConExpandingDicts" $ - getAppDataTyConExpandingDicts scrut_ty + ------------ + size_up_con (Literal lit) nv | isNoRepLit lit = sizeN uNFOLDING_NOREP_LIT_COST + | otherwise = sizeOne - size_up_alts _ (PrimAlts alts deflt) - = foldr (addSize . size_prim_alt) (size_up_deflt deflt) alts - -- *no charge* for a primitive "case"! + size_up_con (DataCon dc) n_val_args = conSizeN n_val_args + + size_up_con (PrimOp op) nv = sizeN op_cost where - size_prim_alt (lit,rhs) = size_up rhs - - ------------ - size_up_deflt NoDefault = sizeZero - size_up_deflt (BindDefault binder rhs) = size_up rhs + op_cost = if primOpOutOfLine op + then uNFOLDING_DEAR_OP_COST + -- these *tend* to be more expensive; + -- number chosen to avoid unfolding (HACK) + else uNFOLDING_CHEAP_OP_COST ------------ - -- Scrutinees. There are two things going on here. - -- First, we want to record if we're case'ing an argument - -- Second, we want to charge nothing for the srutinee if it's just - -- a variable. That way wrapper-like things look cheap. - size_up_scrut (Var v) | v `is_elem` args = Just (0, [v]) - | otherwise = Just (0, []) - size_up_scrut other = size_up other + -- We want to record if we're case'ing an argument + arg_discount (Var v) | v `is_elem` args = scrutArg v + arg_discount other = sizeZero is_elem :: Id -> [Id] -> Bool is_elem = isIn "size_up_scrut" ------------ - sizeZero = Just (0, []) - sizeOne = Just (1, []) - sizeN n = Just (n, []) - sizeVar v = Just (0, [v]) - - addSizeN Nothing _ = Nothing - addSizeN (Just (n, xs)) m - | tot < bOMB_OUT_SIZE = Just (tot, xs) - | otherwise = Nothing - where - tot = n+m + -- These addSize things have to be here because + -- I don't want to give them bOMB_OUT_SIZE as an argument - addSize Nothing _ = Nothing - addSize _ Nothing = Nothing - addSize (Just (n, xs)) (Just (m, ys)) - | tot < bOMB_OUT_SIZE = Just (tot, xys) - | otherwise = Nothing + addSizeN TooBig _ = TooBig + addSizeN (SizeIs n xs d) (I# m) + | n_tot -# d <# bOMB_OUT_SIZE = SizeIs n_tot xs d + | otherwise = TooBig + where + n_tot = n +# m + + addSize TooBig _ = TooBig + addSize _ TooBig = TooBig + addSize (SizeIs n1 xs d1) (SizeIs n2 ys d2) + | (n_tot -# d_tot) <# bOMB_OUT_SIZE = SizeIs n_tot xys d_tot + | otherwise = TooBig where - tot = n+m - xys = xs ++ ys + n_tot = n1 +# n2 + d_tot = d1 +# d2 + xys = xs ++ ys + + +\end{code} + +Code for manipulating sizes + +\begin{code} + +data ExprSize = TooBig + | SizeIs Int# -- Size found + [Id] -- Arguments cased herein + Int# -- Size to subtract if result is scrutinised + -- by a case expression + +sizeZero = SizeIs 0# [] 0# +sizeOne = SizeIs 1# [] 0# +sizeN (I# n) = SizeIs n [] 0# +conSizeN (I# n) = SizeIs 0# [] n -- We don't count 1 for the constructor because we're + -- quite keen to get constructors into the open +scrutArg v = SizeIs 0# [v] 0# + +nukeScrutDiscount (SizeIs n vs d) = SizeIs n vs 0# +nukeScrutDiscount TooBig = TooBig \end{code} %************************************************************************ @@ -376,7 +321,8 @@ purposes here, we assume we've got those. (2)~A ``size'' or ``cost,'' a single integer. (3)~An ``argument info'' vector. For this, what we have at the moment is a Boolean per argument position that says, ``I will look with great favour on an explicit constructor in this -position.'' +position.'' (4)~The ``discount'' to subtract if the expression +is being scrutinised. Assuming we have enough type- and value arguments (if not, we give up immediately), then we see if the ``discounted size'' is below some @@ -385,405 +331,102 @@ position where we're looking for a constructor AND WE HAVE ONE in our hands, we get a (again, semi-arbitrary) discount [proportion to the number of constructors in the type being scrutinized]. -\begin{code} -smallEnoughToInline :: Int -> Int -- Constructor discount and size threshold - -> [Bool] -- Evaluated-ness of value arguments - -> UnfoldingGuidance - -> Bool -- True => unfold it - -smallEnoughToInline con_discount size_threshold _ UnfoldAlways = True -smallEnoughToInline con_discount size_threshold _ UnfoldNever = False -smallEnoughToInline con_discount size_threshold arg_is_evald_s - (UnfoldIfGoodArgs m_tys_wanted n_vals_wanted discount_vec size) - = n_vals_wanted <= length arg_is_evald_s && - discounted_size <= size_threshold - - where - discounted_size = size - sum (zipWith arg_discount discount_vec arg_is_evald_s) - - arg_discount no_of_constrs is_evald - | is_evald = 1 + no_of_constrs * con_discount - | otherwise = 1 -\end{code} - -We use this one to avoid exporting inlinings that we ``couldn't possibly -use'' on the other side. Can be overridden w/ flaggery. -Just the same as smallEnoughToInline, except that it has no actual arguments. +If we're in the context of a scrutinee ( \tr{(case of A .. -> ...;.. )}) +and the expression in question will evaluate to a constructor, we use +the computed discount size *for the result only* rather than +computing the argument discounts. Since we know the result of +the expression is going to be taken apart, discounting its size +is more accurate (see @sizeExpr@ above for how this discount size +is computed). \begin{code} -couldBeSmallEnoughToInline :: Int -> Int -- Constructor discount and size threshold - -> UnfoldingGuidance - -> Bool -- True => unfold it - -couldBeSmallEnoughToInline con_discount size_threshold guidance - = smallEnoughToInline con_discount size_threshold (repeat True) guidance -\end{code} - -%************************************************************************ -%* * -\subsection[unfoldings-for-ifaces]{Processing unfoldings for interfaces} -%* * -%************************************************************************ - -Of course, the main thing we do to unfoldings-for-interfaces is {\em -print} them. But, while we're at it, we collect info about -``mentioned'' Ids, etc., etc.---we're going to need this stuff anyway. - -%************************************************************************ -%* * -\subsubsection{Monad stuff for the unfolding-generation game} -%* * -%************************************************************************ - -\begin{code} -type UnfoldM bndr thing - = IdSet -- in-scope Ids (passed downwards only) - -> (bndr -> Id) -- to extract an Id from a binder (down only) - - -> (Bag Id, -- mentioned global vars (ditto) - Bag TyCon, -- ditto, tycons - Bag Class, -- ditto, classes - Bool) -- True <=> mentions something litlit-ish - - -> (thing, (Bag Id, Bag TyCon, Bag Class, Bool)) -- accumulated... -\end{code} - -A little stuff for in-scopery: -\begin{code} -no_in_scopes :: IdSet -add1 :: IdSet -> Id -> IdSet -add_some :: IdSet -> [Id] -> IdSet - -no_in_scopes = emptyUniqSet -in_scopes `add1` x = addOneToUniqSet in_scopes x -in_scopes `add_some` xs = in_scopes `unionUniqSets` mkUniqSet xs -\end{code} - -The can-see-inside-monad functions are the usual sorts of things. - -\begin{code} -thenUf :: UnfoldM bndr a -> (a -> UnfoldM bndr b) -> UnfoldM bndr b -thenUf m k in_scopes get_id mentioneds - = case m in_scopes get_id mentioneds of { (v, mentioneds1) -> - k v in_scopes get_id mentioneds1 } - -thenUf_ :: UnfoldM bndr a -> UnfoldM bndr b -> UnfoldM bndr b -thenUf_ m k in_scopes get_id mentioneds - = case m in_scopes get_id mentioneds of { (_, mentioneds1) -> - k in_scopes get_id mentioneds1 } - -mapUf :: (a -> UnfoldM bndr b) -> [a] -> UnfoldM bndr [b] -mapUf f [] = returnUf [] -mapUf f (x:xs) - = f x `thenUf` \ r -> - mapUf f xs `thenUf` \ rs -> - returnUf (r:rs) - -returnUf :: a -> UnfoldM bndr a -returnUf v in_scopes get_id mentioneds = (v, mentioneds) - -addInScopesUf :: [Id] -> UnfoldM bndr a -> UnfoldM bndr a -addInScopesUf more_in_scopes m in_scopes get_id mentioneds - = m (in_scopes `add_some` more_in_scopes) get_id mentioneds - -getInScopesUf :: UnfoldM bndr IdSet -getInScopesUf in_scopes get_id mentioneds = (in_scopes, mentioneds) - -extractIdsUf :: [bndr] -> UnfoldM bndr [Id] -extractIdsUf binders in_scopes get_id mentioneds - = (map get_id binders, mentioneds) - -consider_Id :: Id -> UnfoldM bndr () -consider_Id var in_scopes get_id (ids, tcs, clss, has_litlit) - = let - (ids2, tcs2, clss2) = whatsMentionedInId in_scopes var - in - ((), (ids `unionBags` ids2, - tcs `unionBags` tcs2, - clss `unionBags`clss2, - has_litlit)) -\end{code} - -\begin{code} -addToMentionedIdsUf :: Id -> UnfoldM bndr () -addToMentionedTyConsUf :: Bag TyCon -> UnfoldM bndr () -addToMentionedClassesUf :: Bag Class -> UnfoldM bndr () -litlit_oops :: UnfoldM bndr () - -addToMentionedIdsUf add_me in_scopes get_id (ids, tcs, clss, has_litlit) - = ((), (ids `unionBags` unitBag add_me, tcs, clss, has_litlit)) - -addToMentionedTyConsUf add_mes in_scopes get_id (ids, tcs, clss, has_litlit) - = ((), (ids, tcs `unionBags` add_mes, clss, has_litlit)) - -addToMentionedClassesUf add_mes in_scopes get_id (ids, tcs, clss, has_litlit) - = ((), (ids, tcs, clss `unionBags` add_mes, has_litlit)) - -litlit_oops in_scopes get_id (ids, tcs, clss, _) - = ((), (ids, tcs, clss, True)) -\end{code} - - -%************************************************************************ -%* * -\subsubsection{Gathering up info for an interface-unfolding} -%* * -%************************************************************************ +smallEnoughToInline :: Id -- The function (trace msg only) + -> [Bool] -- Evaluated-ness of value arguments + -> Bool -- Result is scrutinised + -> UnfoldingGuidance + -> Bool -- True => unfold it + +smallEnoughToInline _ _ _ UnfoldAlways = True +smallEnoughToInline _ _ _ UnfoldNever = False +smallEnoughToInline id arg_is_evald_s result_is_scruted + (UnfoldIfGoodArgs m_tys_wanted n_vals_wanted discount_vec size scrut_discount) + = if enough_args n_vals_wanted arg_is_evald_s && + size - discount <= opt_UnfoldingUseThreshold + then + True + else + False + where -\begin{code} -{- -mentionedInUnfolding - :: (bndr -> Id) -- so we can get Ids out of binders - -> GenCoreExpr bndr Id -- input expression - -> (Bag Id, Bag TyCon, Bag Class, - -- what we found mentioned in the expr - Bool -- True <=> mentions a ``litlit''-ish thing - -- (the guy on the other side of an interface - -- may not be able to handle it) - ) --} - -mentionedInUnfolding get_id expr - = case (ment_expr expr no_in_scopes get_id (emptyBag, emptyBag, emptyBag, False)) of - (_, (ids_bag, tcs_bag, clss_bag, has_litlit)) -> - (ids_bag, tcs_bag, clss_bag, has_litlit) -\end{code} + enough_args n [] | n > 0 = False -- A function with no value args => don't unfold + enough_args _ _ = True -- Otherwise it's ok to try -\begin{code} ---ment_expr :: GenCoreExpr bndr Id -> UnfoldM bndr () + -- We multiple the raw discounts (args_discount and result_discount) + -- ty opt_UnfoldingKeenessFactor because the former have to do with + -- *size* whereas the discounts imply that there's some extra + -- *efficiency* to be gained (e.g. beta reductions, case reductions) + -- by inlining. -ment_expr (Var v) = consider_Id v -ment_expr (Lit l) = consider_lit l + -- we also discount 1 for each argument passed, because these will + -- reduce with the lambdas in the function (we count 1 for a lambda + -- in size_up). -ment_expr expr@(Lam _ _) - = let - (uvars, tyvars, args, body) = collectBinders expr - in - extractIdsUf args `thenUf` \ bs_ids -> - addInScopesUf bs_ids ( - -- this considering is just to extract any mentioned types/classes - mapUf consider_Id bs_ids `thenUf_` - ment_expr body - ) - -ment_expr (App fun arg) - = ment_expr fun `thenUf_` - ment_arg arg - -ment_expr (Con c as) - = consider_Id c `thenUf_` - mapUf ment_arg as `thenUf_` - returnUf () - -ment_expr (Prim op as) - = ment_op op `thenUf_` - mapUf ment_arg as `thenUf_` - returnUf () - where - ment_op (CCallOp str is_asm may_gc arg_tys res_ty) - = mapUf ment_ty arg_tys `thenUf_` - ment_ty res_ty - ment_op other_op = returnUf () - -ment_expr (Case scrutinee alts) - = ment_expr scrutinee `thenUf_` - ment_alts alts - -ment_expr (Let (NonRec bind rhs) body) - = ment_expr rhs `thenUf_` - extractIdsUf [bind] `thenUf` \ bi@[bind_id] -> - addInScopesUf bi ( - ment_expr body `thenUf_` - consider_Id bind_id ) - -ment_expr (Let (Rec pairs) body) - = let - binders = map fst pairs - rhss = map snd pairs - in - extractIdsUf binders `thenUf` \ binder_ids -> - addInScopesUf binder_ids ( - mapUf ment_expr rhss `thenUf_` - mapUf consider_Id binder_ids `thenUf_` - ment_expr body ) - -ment_expr (SCC cc expr) - = (case (ccMentionsId cc) of - Just id -> consider_Id id - Nothing -> returnUf () - ) - `thenUf_` ment_expr expr - -ment_expr (Coerce _ _ _) = panic "ment_expr:Coerce" - -------------- -ment_ty ty - = let - (tycons, clss) = getMentionedTyConsAndClassesFromType ty - in - addToMentionedTyConsUf tycons `thenUf_` - addToMentionedClassesUf clss + discount :: Int + discount = length (take n_vals_wanted arg_is_evald_s) + + round ( + opt_UnfoldingKeenessFactor * + fromInt (args_discount + result_discount) + ) -------------- + args_discount = sum (zipWith arg_discount discount_vec arg_is_evald_s) + result_discount | result_is_scruted = scrut_discount + | otherwise = 0 -ment_alts alg_alts@(AlgAlts alts deflt) - = mapUf ment_alt alts `thenUf_` - ment_deflt deflt - where - ment_alt alt@(con, params, rhs) - = consider_Id con `thenUf_` - extractIdsUf params `thenUf` \ param_ids -> - addInScopesUf param_ids ( - -- "consider" them so we can chk out their types... - mapUf consider_Id param_ids `thenUf_` - ment_expr rhs ) - -ment_alts (PrimAlts alts deflt) - = mapUf ment_alt alts `thenUf_` - ment_deflt deflt - where - ment_alt alt@(lit, rhs) = ment_expr rhs - ----------------- -ment_deflt NoDefault - = returnUf () - -ment_deflt d@(BindDefault b rhs) - = extractIdsUf [b] `thenUf` \ bi@[b_id] -> - addInScopesUf bi ( - consider_Id b_id `thenUf_` - ment_expr rhs ) - ------------ -ment_arg (VarArg v) = consider_Id v -ment_arg (LitArg l) = consider_lit l -ment_arg (TyArg ty) = ment_ty ty -ment_arg (UsageArg _) = returnUf () - ------------ -consider_lit lit - | isLitLitLit lit = litlit_oops `thenUf_` returnUf () - | otherwise = returnUf () + arg_discount no_of_constrs is_evald + | is_evald = no_of_constrs * opt_UnfoldingConDiscount + | otherwise = 0 \end{code} -%************************************************************************ -%* * -\subsubsection{Printing unfoldings in interfaces} -%* * -%************************************************************************ +We use this one to avoid exporting inlinings that we ``couldn't possibly +use'' on the other side. Can be overridden w/ flaggery. +Just the same as smallEnoughToInline, except that it has no actual arguments. -Printing Core-expression unfoldings is sufficiently delicate that we -give it its own function. \begin{code} -{- OLD: -pprCoreUnfolding - :: CoreExpr - -> Pretty - -pprCoreUnfolding expr - = let - (_, renamed) = instCoreExpr uniqSupply_u expr - -- We rename every unfolding with a "steady" unique supply, - -- so that the names won't constantly change. - -- One place we *MUST NOT* use a splittable UniqueSupply! - in - ppr_uf_Expr emptyUniqSet renamed +couldBeSmallEnoughToInline :: Id -> UnfoldingGuidance -> Bool +couldBeSmallEnoughToInline id guidance = smallEnoughToInline id (repeat True) True guidance -ppr_Unfolding = PprUnfolding (panic "CoreUnfold:ppr_Unfolding") +certainlySmallEnoughToInline :: Id -> UnfoldingGuidance -> Bool +certainlySmallEnoughToInline id guidance = smallEnoughToInline id (repeat False) False guidance \end{code} -\begin{code} -ppr_uf_Expr in_scopes (Var v) = pprIdInUnfolding in_scopes v -ppr_uf_Expr in_scopes (Lit l) = ppr ppr_Unfolding l - -ppr_uf_Expr in_scopes (Con c as) - = ppBesides [ppPStr SLIT("_!_ "), pprIdInUnfolding no_in_scopes c, ppSP, - ppLbrack, ppIntersperse pp'SP{-'-} (map (pprParendUniType ppr_Unfolding) ts), ppRbrack, - ppSP, ppLbrack, ppIntersperse pp'SP{-'-} (map (ppr_uf_Atom in_scopes) as), ppRbrack] -ppr_uf_Expr in_scopes (Prim op as) - = ppBesides [ppPStr SLIT("_#_ "), ppr ppr_Unfolding op, ppSP, - ppLbrack, ppIntersperse pp'SP{-'-} (map (pprParendUniType ppr_Unfolding) ts), ppRbrack, - ppSP, ppLbrack, ppIntersperse pp'SP{-'-} (map (ppr_uf_Atom in_scopes) as), ppRbrack] - -ppr_uf_Expr in_scopes (Lam binder body) - = ppCat [ppChar '\\', ppr_uf_Binder binder, - ppPStr SLIT("->"), ppr_uf_Expr (in_scopes `add1` binder) body] - -ppr_uf_Expr in_scopes (CoTyLam tyvar expr) - = ppCat [ppPStr SLIT("_/\\_"), interppSP ppr_Unfolding (tyvar:tyvars), ppStr "->", - ppr_uf_Expr in_scopes body] - where - (tyvars, body) = collect_tyvars expr - - collect_tyvars (CoTyLam tyv e) = ( tyv:tyvs, e_after ) - where (tyvs, e_after) = collect_tyvars e - collect_tyvars other_e = ( [], other_e ) +@okToUnfoldInHifile@ is used when emitting unfolding info into an interface +file to determine whether an unfolding candidate really should be unfolded. +The predicate is needed to prevent @_casm_@s (+ lit-lits) from being emitted +into interface files. -ppr_uf_Expr in_scopes expr@(App fun_expr atom) - = let - (fun, args) = collect_args expr [] - in - ppCat [ppPStr SLIT("_APP_ "), ppr_uf_Expr in_scopes fun, ppLbrack, - ppIntersperse pp'SP{-'-} (map (ppr_uf_Atom in_scopes) args), ppRbrack] - where - collect_args (App fun arg) args = collect_args fun (arg:args) - collect_args fun args = (fun, args) - -ppr_uf_Expr in_scopes (CoTyApp expr ty) - = ppCat [ppPStr SLIT("_TYAPP_ "), ppr_uf_Expr in_scopes expr, - ppChar '{', pprParendUniType ppr_Unfolding ty, ppChar '}'] - -ppr_uf_Expr in_scopes (Case scrutinee alts) - = ppCat [ppPStr SLIT("case"), ppr_uf_Expr in_scopes scrutinee, ppStr "of {", - pp_alts alts, ppChar '}'] - where - pp_alts (AlgAlts alts deflt) - = ppCat [ppPStr SLIT("_ALG_"), ppCat (map pp_alg alts), pp_deflt deflt] - pp_alts (PrimAlts alts deflt) - = ppCat [ppPStr SLIT("_PRIM_"), ppCat (map pp_prim alts), pp_deflt deflt] - - pp_alg (con, params, rhs) - = ppBesides [pprIdInUnfolding no_in_scopes con, ppSP, - ppIntersperse ppSP (map ppr_uf_Binder params), - ppPStr SLIT(" -> "), ppr_uf_Expr (in_scopes `add_some` params) rhs, ppSemi] - - pp_prim (lit, rhs) - = ppBesides [ppr ppr_Unfolding lit, - ppPStr SLIT(" -> "), ppr_uf_Expr in_scopes rhs, ppSemi] - - pp_deflt NoDefault = ppPStr SLIT("_NO_DEFLT_") - pp_deflt (BindDefault binder rhs) - = ppBesides [ppr_uf_Binder binder, ppPStr SLIT(" -> "), - ppr_uf_Expr (in_scopes `add1` binder) rhs] - -ppr_uf_Expr in_scopes (Let (NonRec binder rhs) body) - = ppBesides [ppStr "let {", ppr_uf_Binder binder, ppPStr SLIT(" = "), ppr_uf_Expr in_scopes rhs, - ppStr "} in ", ppr_uf_Expr (in_scopes `add1` binder) body] - -ppr_uf_Expr in_scopes (Let (Rec pairs) body) - = ppBesides [ppStr "_LETREC_ {", ppIntersperse sep (map pp_pair pairs), - ppStr "} in ", ppr_uf_Expr new_in_scopes body] - where - sep = ppBeside ppSemi ppSP - new_in_scopes = in_scopes `add_some` map fst pairs - - pp_pair (b, rhs) = ppCat [ppr_uf_Binder b, ppEquals, ppr_uf_Expr new_in_scopes rhs] - -ppr_uf_Expr in_scopes (SCC cc body) - = ASSERT(not (noCostCentreAttached cc)) - ASSERT(not (currentOrSubsumedCosts cc)) - ppBesides [ppStr "_scc_ { ", ppStr (showCostCentre ppr_Unfolding False{-not as string-} cc), ppStr " } ", ppr_uf_Expr in_scopes body] - -ppr_uf_Expr in_scopes (Coerce _ _ _) = panic "ppr_uf_Expr:Coerce" -\end{code} +The reason for inlining expressions containing _casm_s into interface files +is that these fragments of C are likely to mention functions/#defines that +will be out-of-scope when inlined into another module. This is not an +unfixable problem for the user (just need to -#include the approp. header +file), but turning it off seems to the simplest thing to do. \begin{code} -ppr_uf_Binder :: Id -> Pretty -ppr_uf_Binder v - = ppBesides [ppLparen, pprIdInUnfolding (unitUniqSet v) v, ppPStr SLIT(" :: "), - ppr ppr_Unfolding (idType v), ppRparen] - -ppr_uf_Atom in_scopes (LitArg l) = ppr ppr_Unfolding l -ppr_uf_Atom in_scopes (VarArg v) = pprIdInUnfolding in_scopes v -END OLD -} +okToUnfoldInHiFile :: CoreExpr -> Bool +okToUnfoldInHiFile e = opt_UnfoldCasms || go e + where + -- Race over an expression looking for CCalls.. + go (Var _) = True + go (Con (Literal lit) _) = not (isLitLitLit lit) + go (Con (PrimOp op) args) = okToUnfoldPrimOp op && all go args + go (Con con args) = True -- con args are always atomic + go (App fun arg) = go fun && go arg + go (Lam _ body) = go body + go (Let binds body) = and (map go (body :rhssOfBind binds)) + go (Case scrut bndr alts) = and (map go (scrut:rhssOfAlts alts)) + go (Note _ body) = go body + go (Type _) = True + + -- ok to unfold a PrimOp as long as it's not a _casm_ + okToUnfoldPrimOp (CCallOp _ is_casm _ _) = not is_casm + okToUnfoldPrimOp _ = True \end{code}