X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreSyn.lhs;h=2c89f6eabcb204e96dae90507ba4cca0fca3e57b;hb=3063cb3d629610339d5f1c38d244617977c5fd21;hp=94aa74156a1631b773b9b0617dcb0805fd90c2a0;hpb=30b5ebe424ebae69b162ac3fc547eb14d898535f;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreSyn.lhs b/ghc/compiler/coreSyn/CoreSyn.lhs index 94aa741..2c89f6e 100644 --- a/ghc/compiler/coreSyn/CoreSyn.lhs +++ b/ghc/compiler/coreSyn/CoreSyn.lhs @@ -5,49 +5,56 @@ \begin{code} module CoreSyn ( - Expr(..), Alt, Bind(..), Arg(..), Note(..), + Expr(..), Alt, Bind(..), AltCon(..), Arg, Note(..), CoreExpr, CoreAlt, CoreBind, CoreArg, CoreBndr, TaggedExpr, TaggedAlt, TaggedBind, TaggedArg, - mkLets, mkLams, + mkLets, mkLams, mkApps, mkTyApps, mkValApps, mkVarApps, - mkLit, mkStringLit, mkConApp, mkPrimApp, mkNote, - bindNonRec, mkIfThenElse, varToCoreExpr, + mkLit, mkIntLitInt, mkIntLit, + mkConApp, + varToCoreExpr, - bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, isDeadBinder, isTyVar, isId, + isTyVar, isId, + bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, collectBinders, collectTyBinders, collectValBinders, collectTyAndValBinders, collectArgs, collectBindersIgnoringNotes, coreExprCc, flattenBinds, - isValArg, isTypeArg, valArgCount, valBndrCount, + isValArg, isTypeArg, valArgCount, valBndrCount, isRuntimeArg, isRuntimeVar, - -- Seq stuff - seqRules, seqExpr, seqExprs, + -- Unfoldings + Unfolding(..), UnfoldingGuidance(..), -- Both abstract everywhere but in CoreUnfold.lhs + noUnfolding, mkOtherCon, + unfoldingTemplate, maybeUnfoldingTemplate, otherCons, + isValueUnfolding, isEvaldUnfolding, isCheapUnfolding, isCompulsoryUnfolding, + hasUnfolding, hasSomeUnfolding, neverUnfold, - -- Size - coreBindsSize, + -- Seq stuff + seqRules, seqExpr, seqExprs, seqUnfolding, -- Annotated expressions - AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt, deAnnotate, + AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt, + deAnnotate, deAnnotate', deAnnAlt, -- Core rules CoreRules(..), -- Representation needed by friends CoreRule(..), -- CoreSubst, CoreTidy, CoreFVs, PprCore only - emptyCoreRules, isEmptyCoreRules, rulesRhsFreeVars, rulesRules + IdCoreRule, + RuleName, + emptyCoreRules, isEmptyCoreRules, rulesRhsFreeVars, rulesRules, + isBuiltinRule ) where #include "HsVersions.h" -import TysWiredIn ( boolTy, stringTy, nilDataCon ) -import CostCentre ( CostCentre, isDupdCC, noCostCentre ) -import Var ( Var, Id, TyVar, IdOrTyVar, isTyVar, isId, idType ) -import VarEnv -import Id ( mkWildId, getIdOccInfo, idInfo ) -import Type ( Type, UsageAnn, mkTyVarTy, isUnLiftedType, seqType ) -import IdInfo ( OccInfo(..), megaSeqIdInfo ) -import Const ( Con(..), DataCon, Literal(NoRepStr), PrimOp ) -import TysWiredIn ( trueDataCon, falseDataCon ) +import CmdLineOpts ( opt_RuntimeTypes ) +import CostCentre ( CostCentre, noCostCentre ) +import Var ( Var, Id, TyVar, isTyVar, isId ) +import Type ( Type, mkTyVarTy, seqType ) +import Literal ( Literal, mkMachInt ) +import DataCon ( DataCon, dataConId ) import VarSet import Outputable \end{code} @@ -65,23 +72,24 @@ infixl 8 `App` -- App brackets to the left data Expr b -- "b" for the type of binders, = Var Id - | Con Con [Arg b] -- Guaranteed saturated - -- The Con can be a DataCon, Literal, PrimOP - -- but cannot be DEFAULT + | Lit Literal | App (Expr b) (Arg b) | Lam b (Expr b) | Let (Bind b) (Expr b) | Case (Expr b) b [Alt b] -- Binder gets bound to value of scrutinee - -- DEFAULT case must be last, if it occurs at all + -- DEFAULT case must be *first*, if it occurs at all | Note Note (Expr b) | Type Type -- This should only show up at the top -- level of an Arg type Arg b = Expr b -- Can be a Type -type Alt b = (Con, [b], Expr b) - -- (DEFAULT, [], rhs) is the default alternative - -- The Con can be a Literal, DataCon, or DEFAULT, but cannot be PrimOp +type Alt b = (AltCon, [b], Expr b) -- (DEFAULT, [], rhs) is the default alternative + +data AltCon = DataAlt DataCon + | LitAlt Literal + | DEFAULT + deriving (Eq, Ord) data Bind b = NonRec b (Expr b) | Rec [(b, (Expr b))] @@ -99,10 +107,34 @@ data Note | InlineMe -- Instructs simplifer to treat the enclosed expression -- as very small, and inline it at its call sites - | TermUsg -- A term-level usage annotation - UsageAnn -- (should not be a variable except during UsageSP inference) +-- NOTE: we also treat expressions wrapped in InlineMe as +-- 'cheap' and 'dupable' (in the sense of exprIsCheap, exprIsDupable) +-- What this means is that we obediently inline even things that don't +-- look like valuse. This is sometimes important: +-- {-# INLINE f #-} +-- f = g . h +-- Here, f looks like a redex, and we aren't going to inline (.) because it's +-- inside an INLINE, so it'll stay looking like a redex. Nevertheless, we +-- should inline f even inside lambdas. In effect, we should trust the programmer. \end{code} +INVARIANTS: + +* The RHS of a letrec, and the RHSs of all top-level lets, + must be of LIFTED type. + +* The RHS of a let, may be of UNLIFTED type, but only if the expression + is ok-for-speculation. This means that the let can be floated around + without difficulty. e.g. + y::Int# = x +# 1# ok + y::Int# = fac 4# not ok [use case instead] + +* The argument of an App can be of any type. + +* The simplifier tries to ensure that if the RHS of a let is a constructor + application, its arguments are trivial, so that the constructor can be + inlined vigorously. + %************************************************************************ %* * @@ -116,13 +148,7 @@ but CoreFVs, Subst, PprCore, CoreTidy also inspect the representation. \begin{code} data CoreRules = Rules [CoreRule] - IdOrTyVarSet -- Locally-defined free vars of RHSs - -data CoreRule - = Rule FAST_STRING -- Rule name - [CoreBndr] -- Forall'd variables - [CoreExpr] -- LHS args - CoreExpr -- RHS + VarSet -- Locally-defined free vars of RHSs emptyCoreRules :: CoreRules emptyCoreRules = Rules [] emptyVarSet @@ -130,13 +156,166 @@ emptyCoreRules = Rules [] emptyVarSet isEmptyCoreRules :: CoreRules -> Bool isEmptyCoreRules (Rules rs _) = null rs -rulesRhsFreeVars :: CoreRules -> IdOrTyVarSet +rulesRhsFreeVars :: CoreRules -> VarSet rulesRhsFreeVars (Rules _ fvs) = fvs rulesRules :: CoreRules -> [CoreRule] rulesRules (Rules rules _) = rules \end{code} +\begin{code} +type RuleName = FAST_STRING +type IdCoreRule = (Id,CoreRule) -- Rules don't have their leading Id inside them + +data CoreRule + = Rule RuleName + [CoreBndr] -- Forall'd variables + [CoreExpr] -- LHS args + CoreExpr -- RHS + + | BuiltinRule -- Built-in rules are used for constant folding + -- and suchlike. It has no free variables. + ([CoreExpr] -> Maybe (RuleName, CoreExpr)) + +isBuiltinRule (BuiltinRule _) = True +isBuiltinRule _ = False +\end{code} + + +%************************************************************************ +%* * +\subsection{@Unfolding@ type} +%* * +%************************************************************************ + +The @Unfolding@ type is declared here to avoid numerous loops, but it +should be abstract everywhere except in CoreUnfold.lhs + +\begin{code} +data Unfolding + = NoUnfolding + + | OtherCon [AltCon] -- 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. + + | CompulsoryUnfolding CoreExpr -- There is no "original" definition, + -- so you'd better unfold. + + | CoreUnfolding -- An unfolding with redundant cached information + CoreExpr -- Template; binder-info is correct + Bool -- True <=> top level binding + Bool -- exprIsValue template (cached); it is ok to discard a `seq` on + -- this variable + Bool -- True <=> doesn't waste (much) work to expand inside an inlining + -- Basically it's exprIsCheap + UnfoldingGuidance -- Tells about the *size* of the template. + + +data UnfoldingGuidance + = UnfoldNever + | UnfoldIfGoodArgs 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.) + +noUnfolding = NoUnfolding +mkOtherCon = OtherCon + +seqUnfolding :: Unfolding -> () +seqUnfolding (CoreUnfolding e top b1 b2 g) + = seqExpr e `seq` top `seq` b1 `seq` b2 `seq` seqGuidance g +seqUnfolding other = () + +seqGuidance (UnfoldIfGoodArgs n ns a b) = n `seq` sum ns `seq` a `seq` b `seq` () +seqGuidance other = () +\end{code} + +\begin{code} +unfoldingTemplate :: Unfolding -> CoreExpr +unfoldingTemplate (CoreUnfolding expr _ _ _ _) = expr +unfoldingTemplate (CompulsoryUnfolding expr) = expr +unfoldingTemplate other = panic "getUnfoldingTemplate" + +maybeUnfoldingTemplate :: Unfolding -> Maybe CoreExpr +maybeUnfoldingTemplate (CoreUnfolding expr _ _ _ _) = Just expr +maybeUnfoldingTemplate (CompulsoryUnfolding expr) = Just expr +maybeUnfoldingTemplate other = Nothing + +otherCons :: Unfolding -> [AltCon] +otherCons (OtherCon cons) = cons +otherCons other = [] + +isValueUnfolding :: Unfolding -> Bool + -- Returns False for OtherCon +isValueUnfolding (CoreUnfolding _ _ is_evald _ _) = is_evald +isValueUnfolding other = False + +isEvaldUnfolding :: Unfolding -> Bool + -- Returns True for OtherCon +isEvaldUnfolding (OtherCon _) = True +isEvaldUnfolding (CoreUnfolding _ _ is_evald _ _) = is_evald +isEvaldUnfolding other = False + +isCheapUnfolding :: Unfolding -> Bool +isCheapUnfolding (CoreUnfolding _ _ _ is_cheap _) = is_cheap +isCheapUnfolding other = False + +isCompulsoryUnfolding :: Unfolding -> Bool +isCompulsoryUnfolding (CompulsoryUnfolding _) = True +isCompulsoryUnfolding other = False + +hasUnfolding :: Unfolding -> Bool +hasUnfolding (CoreUnfolding _ _ _ _ _) = True +hasUnfolding (CompulsoryUnfolding _) = True +hasUnfolding other = False + +hasSomeUnfolding :: Unfolding -> Bool +hasSomeUnfolding NoUnfolding = False +hasSomeUnfolding other = True + +neverUnfold :: Unfolding -> Bool +neverUnfold NoUnfolding = True +neverUnfold (OtherCon _) = True +neverUnfold (CoreUnfolding _ _ _ _ UnfoldNever) = True +neverUnfold other = False +\end{code} + + +%************************************************************************ +%* * +\subsection{The main data type} +%* * +%************************************************************************ + +\begin{code} +-- The Ord is needed for the FiniteMap used in the lookForConstructor +-- in SimplEnv. If you declared that lookForConstructor *ignores* +-- constructor-applications with LitArg args, then you could get +-- rid of this Ord. + +instance Outputable AltCon where + ppr (DataAlt dc) = ppr dc + ppr (LitAlt lit) = ppr lit + ppr DEFAULT = ptext SLIT("__DEFAULT") + +instance Show AltCon where + showsPrec p con = showsPrecSDoc p (ppr con) +\end{code} + %************************************************************************ %* * @@ -147,12 +326,11 @@ rulesRules (Rules rules _) = rules The common case \begin{code} -type CoreBndr = IdOrTyVar +type CoreBndr = Var type CoreExpr = Expr CoreBndr type CoreArg = Arg CoreBndr type CoreBind = Bind CoreBndr type CoreAlt = Alt CoreBndr -type CoreNote = Note \end{code} Binders are ``tagged'' with a \tr{t}: @@ -177,86 +355,35 @@ type TaggedAlt t = Alt (Tagged t) mkApps :: Expr b -> [Arg b] -> Expr b mkTyApps :: Expr b -> [Type] -> Expr b mkValApps :: Expr b -> [Expr b] -> Expr b -mkVarApps :: CoreExpr -> [IdOrTyVar] -> CoreExpr +mkVarApps :: Expr b -> [Var] -> Expr b mkApps f args = foldl App f args mkTyApps f args = foldl (\ e a -> App e (Type a)) f args mkValApps f args = foldl (\ e a -> App e a) f args mkVarApps f vars = foldl (\ e a -> App e (varToCoreExpr a)) f vars -mkLit :: Literal -> Expr b -mkStringLit :: String -> Expr b -mkConApp :: DataCon -> [Arg b] -> Expr b -mkPrimApp :: PrimOp -> [Arg b] -> Expr b +mkLit :: Literal -> Expr b +mkIntLit :: Integer -> Expr b +mkIntLitInt :: Int -> Expr b +mkConApp :: DataCon -> [Arg b] -> Expr b +mkLets :: [Bind b] -> Expr b -> Expr b +mkLams :: [b] -> Expr b -> Expr b -mkLit lit = Con (Literal lit) [] -mkStringLit str = Con (Literal (NoRepStr (_PK_ str) stringTy)) [] -mkConApp con args = Con (DataCon con) args -mkPrimApp op args = Con (PrimOp op) args +mkLit lit = Lit lit +mkConApp con args = mkApps (Var (dataConId con)) args -varToCoreExpr :: CoreBndr -> CoreExpr -varToCoreExpr v | isId v = Var v - | otherwise = Type (mkTyVarTy v) -\end{code} - -\begin{code} -mkLams :: [b] -> Expr b -> Expr b mkLams binders body = foldr Lam body binders -\end{code} +mkLets binds body = foldr Let body binds -\begin{code} -mkLets :: [Bind b] -> Expr b -> Expr b -mkLets binds body = foldr Let body binds - -bindNonRec :: Id -> CoreExpr -> CoreExpr -> CoreExpr --- (bindNonRec x r b) produces either --- let x = r in b --- or --- case r of x { _DEFAULT_ -> b } --- --- depending on whether x is unlifted or not --- It's used by the desugarer to avoid building bindings --- that give Core Lint a heart attack. Actually the simplifier --- deals with them perfectly well. -bindNonRec bndr rhs body - | isUnLiftedType (idType bndr) = Case rhs bndr [(DEFAULT,[],body)] - | otherwise = Let (NonRec bndr rhs) body - -mkIfThenElse :: CoreExpr -> CoreExpr -> CoreExpr -> CoreExpr -mkIfThenElse guard then_expr else_expr - = Case guard (mkWildId boolTy) - [ (DataCon trueDataCon, [], then_expr), - (DataCon falseDataCon, [], else_expr) ] -\end{code} - -mkNote removes redundant coercions, and SCCs where possible - -\begin{code} -mkNote :: Note -> Expr b -> Expr b -mkNote (Coerce to_ty1 from_ty1) (Note (Coerce to_ty2 from_ty2) expr) - = ASSERT( from_ty1 == to_ty2 ) - mkNote (Coerce to_ty1 from_ty2) expr - -mkNote (SCC cc1) expr@(Note (SCC cc2) _) - | isDupdCC cc1 -- Discard the outer SCC provided we don't need - = expr -- to track its entry count +mkIntLit n = Lit (mkMachInt n) +mkIntLitInt n = Lit (mkMachInt (toInteger n)) -mkNote note@(SCC cc1) expr@(Lam x e) -- Move _scc_ inside lambda - = Lam x (mkNote note e) - --- Drop trivial InlineMe's -mkNote InlineMe expr@(Con _ _) = expr -mkNote InlineMe expr@(Var v) = expr - --- Slide InlineCall in around the function --- No longer necessary I think (SLPJ Apr 99) --- mkNote InlineCall (App f a) = App (mkNote InlineCall f) a --- mkNote InlineCall (Var v) = Note InlineCall (Var v) --- mkNote InlineCall expr = expr - -mkNote note expr = Note note expr +varToCoreExpr :: CoreBndr -> Expr b +varToCoreExpr v | isId v = Var v + | otherwise = Type (mkTyVarTy v) \end{code} + %************************************************************************ %* * \subsection{Simple access functions} @@ -278,12 +405,6 @@ rhssOfBind (Rec pairs) = [rhs | (_,rhs) <- pairs] rhssOfAlts :: [Alt b] -> [Expr b] rhssOfAlts alts = [e | (_,_,e) <- alts] -isDeadBinder :: CoreBndr -> Bool -isDeadBinder bndr | isId bndr = case getIdOccInfo bndr of - IAmDead -> True - other -> False - | otherwise = False -- TyVars count as not dead - flattenBinds :: [Bind b] -> [(b, Expr b)] -- Get all the lhs/rhs pairs flattenBinds (NonRec b r : binds) = (b,r) : flattenBinds binds flattenBinds (Rec prs1 : binds) = prs1 ++ flattenBinds binds @@ -363,12 +484,29 @@ coreExprCc other = noCostCentre \end{code} + %************************************************************************ %* * \subsection{Predicates} %* * %************************************************************************ +@isRuntimeVar v@ returns if (Lam v _) really becomes a lambda at runtime, +i.e. if type applications are actual lambdas because types are kept around +at runtime. + +Similarly isRuntimeArg. + +\begin{code} +isRuntimeVar :: Var -> Bool +isRuntimeVar | opt_RuntimeTypes = \v -> True + | otherwise = \v -> isId v + +isRuntimeArg :: CoreExpr -> Bool +isRuntimeArg | opt_RuntimeTypes = \e -> True + | otherwise = \e -> isValArg e +\end{code} + \begin{code} isValArg (Type _) = False isValArg other = True @@ -397,7 +535,7 @@ valArgCount (other : args) = 1 + valArgCount args \begin{code} seqExpr :: CoreExpr -> () seqExpr (Var v) = v `seq` () -seqExpr (Con c as) = seqExprs as +seqExpr (Lit lit) = lit `seq` () seqExpr (App f a) = seqExpr f `seq` seqExpr a seqExpr (Lam b e) = seqBndr b `seq` seqExpr e seqExpr (Let b e) = seqBind b `seq` seqExpr e @@ -430,41 +568,9 @@ seqRules (Rules rules fvs) = seq_rules rules `seq` seqVarSet fvs seq_rules [] = () seq_rules (Rule fs bs es e : rules) = seqBndrs bs `seq` seqExprs (e:es) `seq` seq_rules rules +seq_rules (BuiltinRule _ : rules) = seq_rules rules \end{code} -\begin{code} -coreBindsSize :: [CoreBind] -> Int -coreBindsSize bs = foldr ((+) . bindSize) 0 bs - -exprSize :: CoreExpr -> Int - -- A measure of the size of the expressions - -- It also forces the expression pretty drastically as a side effect -exprSize (Var v) = varSize v -exprSize (Con c as) = c `seq` exprsSize as -exprSize (App f a) = exprSize f + exprSize a -exprSize (Lam b e) = varSize b + exprSize e -exprSize (Let b e) = bindSize b + exprSize e -exprSize (Case e b as) = exprSize e + varSize b + foldr ((+) . altSize) 0 as -exprSize (Note n e) = exprSize e -exprSize (Type t) = seqType t `seq` 1 - -exprsSize = foldr ((+) . exprSize) 0 - -varSize :: IdOrTyVar -> Int -varSize b | isTyVar b = 1 - | otherwise = seqType (idType b) `seq` - megaSeqIdInfo (idInfo b) `seq` - 1 - -varsSize = foldr ((+) . varSize) 0 - -bindSize (NonRec b e) = varSize b + exprSize e -bindSize (Rec prs) = foldr ((+) . pairSize) 0 prs - -pairSize (b,e) = varSize b + exprSize e - -altSize (c,bs,e) = c `seq` varsSize bs + exprSize e -\end{code} %************************************************************************ @@ -478,7 +584,7 @@ type AnnExpr bndr annot = (annot, AnnExpr' bndr annot) data AnnExpr' bndr annot = AnnVar Id - | AnnCon Con [AnnExpr bndr annot] + | AnnLit Literal | AnnLam bndr (AnnExpr bndr annot) | AnnApp (AnnExpr bndr annot) (AnnExpr bndr annot) | AnnCase (AnnExpr bndr annot) bndr [AnnAlt bndr annot] @@ -486,7 +592,7 @@ data AnnExpr' bndr annot | AnnNote Note (AnnExpr bndr annot) | AnnType Type -type AnnAlt bndr annot = (Con, [bndr], AnnExpr bndr annot) +type AnnAlt bndr annot = (AltCon, [bndr], AnnExpr bndr annot) data AnnBind bndr annot = AnnNonRec bndr (AnnExpr bndr annot) @@ -495,23 +601,25 @@ data AnnBind bndr annot \begin{code} deAnnotate :: AnnExpr bndr annot -> Expr bndr +deAnnotate (_, e) = deAnnotate' e -deAnnotate (_, AnnType t) = Type t -deAnnotate (_, AnnVar v) = Var v -deAnnotate (_, AnnCon con args) = Con con (map deAnnotate args) -deAnnotate (_, AnnLam binder body)= Lam binder (deAnnotate body) -deAnnotate (_, AnnApp fun arg) = App (deAnnotate fun) (deAnnotate arg) -deAnnotate (_, AnnNote note body) = Note note (deAnnotate body) +deAnnotate' (AnnType t) = Type t +deAnnotate' (AnnVar v) = Var v +deAnnotate' (AnnLit lit) = Lit lit +deAnnotate' (AnnLam binder body) = Lam binder (deAnnotate body) +deAnnotate' (AnnApp fun arg) = App (deAnnotate fun) (deAnnotate arg) +deAnnotate' (AnnNote note body) = Note note (deAnnotate body) -deAnnotate (_, AnnLet bind body) +deAnnotate' (AnnLet bind body) = Let (deAnnBind bind) (deAnnotate body) where deAnnBind (AnnNonRec var rhs) = NonRec var (deAnnotate rhs) deAnnBind (AnnRec pairs) = Rec [(v,deAnnotate rhs) | (v,rhs) <- pairs] -deAnnotate (_, AnnCase scrut v alts) +deAnnotate' (AnnCase scrut v alts) = Case (deAnnotate scrut) v (map deAnnAlt alts) - where - deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs) + +deAnnAlt :: AnnAlt bndr annot -> Alt bndr +deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs) \end{code}