X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FstgSyn%2FCoreToStg.lhs;h=824cabaacbd51c1468cf5ea6d56c8143c3a5edfc;hb=28a464a75e14cece5db40f2765a29348273ff2d2;hp=13c937efd3a3498084127a874e600a015ffa7b4e;hpb=17e8f5c279e5d23cfd44d25298646426d39342c8;p=ghc-hetmet.git diff --git a/ghc/compiler/stgSyn/CoreToStg.lhs b/ghc/compiler/stgSyn/CoreToStg.lhs index 13c937e..824caba 100644 --- a/ghc/compiler/stgSyn/CoreToStg.lhs +++ b/ghc/compiler/stgSyn/CoreToStg.lhs @@ -12,32 +12,30 @@ module CoreToStg ( coreToStg, coreExprToStg ) where #include "HsVersions.h" import CoreSyn -import CoreUtils +import CoreUtils ( rhsIsStatic, manifestArity, exprType, findDefault ) import StgSyn import Type import TyCon ( isAlgTyCon ) -import Literal import Id -import Var ( Var, globalIdDetails ) +import Var ( Var, globalIdDetails, idType ) +import TyCon ( isUnboxedTupleTyCon, isPrimTyCon, isFunTyCon, isHiBootTyCon ) +#ifdef ILX +import MkId ( unsafeCoerceId ) +#endif import IdInfo import DataCon import CostCentre ( noCCS ) import VarSet import VarEnv -import DataCon ( dataConWrapId ) -import IdInfo ( OccInfo(..) ) -import TysPrim ( foreignObjPrimTyCon ) import Maybes ( maybeToBool ) -import Name ( getOccName, isExternallyVisibleName, isDllName ) -import OccName ( occNameUserString ) -import BasicTypes ( TopLevelFlag(..), isNotTopLevel, Arity ) -import CmdLineOpts ( DynFlags, opt_KeepStgTypes ) -import FastTypes hiding ( fastOr ) +import Name ( getOccName, isExternalName, nameOccName ) +import OccName ( occNameString, occNameFS ) +import BasicTypes ( Arity ) +import Packages ( HomeModules ) +import StaticFlags ( opt_RuntimeTypes ) import Outputable -import List ( partition ) - infixr 9 `thenLne` \end{code} @@ -105,8 +103,7 @@ A top-level Id has CafInfo, which is one or more CAFs, or - NoCafRefs if it definitely doesn't -we collect the CafInfo first by analysing the original Core expression, and -also place this information in the environment. +The CafInfo has already been calculated during the CoreTidy pass. During CoreToStg, we then pin onto each binding and case expression, a list of Ids which represents the "live" CAFs at that point. The meaning @@ -117,6 +114,25 @@ The later SRT pass takes these lists of Ids and uses them to construct the actual nested SRTs, and replaces the lists of Ids with (offset,length) pairs. + +Interaction of let-no-escape with SRTs [Sept 01] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider + + let-no-escape x = ...caf1...caf2... + in + ...x...x...x... + +where caf1,caf2 are CAFs. Since x doesn't have a closure, we +build SRTs just as if x's defn was inlined at each call site, and +that means that x's CAF refs get duplicated in the overall SRT. + +This is unlike ordinary lets, in which the CAF refs are not duplicated. + +We could fix this loss of (static) sharing by making a sort of pseudo-closure +for x, solely to put in the SRTs lower down. + + %************************************************************************ %* * \subsection[binds-StgVarInfo]{Setting variable info: top-level, binds, RHSs} @@ -124,10 +140,10 @@ pairs. %************************************************************************ \begin{code} -coreToStg :: DynFlags -> [CoreBind] -> IO [StgBinding] -coreToStg dflags pgm +coreToStg :: HomeModules -> [CoreBind] -> IO [StgBinding] +coreToStg hmods pgm = return pgm' - where (env', fvs, pgm') = coreTopBindsToStg emptyVarEnv pgm + where (_, _, pgm') = coreTopBindsToStg hmods emptyVarEnv pgm coreExprToStg :: CoreExpr -> StgExpr coreExprToStg expr @@ -135,167 +151,122 @@ coreExprToStg expr coreTopBindsToStg - :: IdEnv HowBound -- environment for the bindings + :: HomeModules + -> IdEnv HowBound -- environment for the bindings -> [CoreBind] -> (IdEnv HowBound, FreeVarsInfo, [StgBinding]) -coreTopBindsToStg env [] = (env, emptyFVInfo, []) -coreTopBindsToStg env (b:bs) - = (env2, fvs1, b':bs') +coreTopBindsToStg hmods env [] = (env, emptyFVInfo, []) +coreTopBindsToStg hmods env (b:bs) + = (env2, fvs2, b':bs') where -- env accumulates down the list of binds, fvs accumulates upwards - (env1, fvs2, b' ) = coreTopBindToStg env fvs1 b - (env2, fvs1, bs') = coreTopBindsToStg env1 bs + (env1, fvs2, b' ) = coreTopBindToStg hmods env fvs1 b + (env2, fvs1, bs') = coreTopBindsToStg hmods env1 bs coreTopBindToStg - :: IdEnv HowBound + :: HomeModules + -> IdEnv HowBound -> FreeVarsInfo -- Info about the body -> CoreBind -> (IdEnv HowBound, FreeVarsInfo, StgBinding) -coreTopBindToStg env body_fvs (NonRec id rhs) +coreTopBindToStg hmods env body_fvs (NonRec id rhs) = let - caf_info = hasCafRefs env rhs - arity = exprArity rhs - - env' = extendVarEnv env id (LetBound how_bound emptyVarSet arity) - - how_bound | mayHaveCafRefs caf_info = TopLevelHasCafs - | otherwise = TopLevelNoCafs + env' = extendVarEnv env id how_bound + how_bound = LetBound TopLet $! manifestArity rhs - (stg_rhs, fvs', cafs) = + (stg_rhs, fvs') = initLne env ( - coreToStgRhs body_fvs TopLevel (id,rhs) - `thenLne` \ (stg_rhs, fvs', _) -> - freeVarsToLiveVars fvs' `thenLne` \ (_, cafs) -> - returnLne (stg_rhs, fvs', cafs) + coreToTopStgRhs hmods body_fvs (id,rhs) `thenLne` \ (stg_rhs, fvs') -> + returnLne (stg_rhs, fvs') ) - bind = StgNonRec (SRTEntries cafs) id stg_rhs + bind = StgNonRec id stg_rhs in - ASSERT2(consistent caf_info bind, ppr id) + ASSERT2(manifestArity rhs == stgRhsArity stg_rhs, ppr id) + ASSERT2(consistentCafInfo id bind, ppr id) -- WARN(not (consistent caf_info bind), ppr id <+> ppr cafs <+> ppCafInfo caf_info) (env', fvs' `unionFVInfo` body_fvs, bind) -coreTopBindToStg env body_fvs (Rec pairs) +coreTopBindToStg hmods env body_fvs (Rec pairs) = let (binders, rhss) = unzip pairs - -- to calculate caf_info, we initially map all the binders to - -- TopLevelNoCafs. - env1 = extendVarEnvList env - [ (b, LetBound TopLevelNoCafs emptyVarSet (error "no arity")) - | b <- binders ] + extra_env' = [ (b, LetBound TopLet $! manifestArity rhs) + | (b, rhs) <- pairs ] + env' = extendVarEnvList env extra_env' - caf_info = hasCafRefss env1{-NB: not env'-} rhss - - env' = extendVarEnvList env - [ (b, LetBound how_bound emptyVarSet (exprArity rhs)) - | (b,rhs) <- pairs ] - - how_bound | mayHaveCafRefs caf_info = TopLevelHasCafs - | otherwise = TopLevelNoCafs - - (stg_rhss, fvs', cafs) + (stg_rhss, fvs') = initLne env' ( - mapAndUnzip3Lne (coreToStgRhs body_fvs TopLevel) pairs - `thenLne` \ (stg_rhss, fvss', _) -> + mapAndUnzipLne (coreToTopStgRhs hmods body_fvs) pairs + `thenLne` \ (stg_rhss, fvss') -> let fvs' = unionFVInfos fvss' in - freeVarsToLiveVars fvs' `thenLne` \ (_, cafs) -> - returnLne (stg_rhss, fvs', cafs) + returnLne (stg_rhss, fvs') ) - bind = StgRec (SRTEntries cafs) (zip binders stg_rhss) + bind = StgRec (zip binders stg_rhss) in - ASSERT2(consistent caf_info bind, ppr binders) --- WARN(not (consistent caf_info bind), ppr binders <+> ppr cafs <+> ppCafInfo caf_info) + ASSERT2(and [manifestArity rhs == stgRhsArity stg_rhs | (rhs,stg_rhs) <- rhss `zip` stg_rhss], ppr binders) + ASSERT2(consistentCafInfo (head binders) bind, ppr binders) (env', fvs' `unionFVInfo` body_fvs, bind) --- assertion helper -consistent caf_info bind = mayHaveCafRefs caf_info == stgBindHasCafRefs bind +#ifdef DEBUG +-- Assertion helper: this checks that the CafInfo on the Id matches +-- what CoreToStg has figured out about the binding's SRT. The +-- CafInfo will be exact in all cases except when CorePrep has +-- floated out a binding, in which case it will be approximate. +consistentCafInfo id bind + | occNameFS (nameOccName (idName id)) == FSLIT("sat") + = safe + | otherwise + = WARN (not exact, ppr id) safe + where + safe = id_marked_caffy || not binding_is_caffy + exact = id_marked_caffy == binding_is_caffy + id_marked_caffy = mayHaveCafRefs (idCafInfo id) + binding_is_caffy = stgBindHasCafRefs bind +#endif \end{code} \begin{code} -coreToStgRhs - :: FreeVarsInfo -- Free var info for the scope of the binding - -> TopLevelFlag +coreToTopStgRhs + :: HomeModules + -> FreeVarsInfo -- Free var info for the scope of the binding -> (Id,CoreExpr) - -> LneM (StgRhs, FreeVarsInfo, EscVarsSet) + -> LneM (StgRhs, FreeVarsInfo) -coreToStgRhs scope_fv_info top (binder, rhs) - = coreToStgExpr rhs `thenLne` \ (new_rhs, rhs_fvs, rhs_escs) -> - returnLne (mkStgRhs top rhs_fvs binder_info new_rhs, - rhs_fvs, rhs_escs) +coreToTopStgRhs hmods scope_fv_info (bndr, rhs) + = coreToStgExpr rhs `thenLne` \ (new_rhs, rhs_fvs, _) -> + freeVarsToLiveVars rhs_fvs `thenLne` \ lv_info -> + returnLne (mkTopStgRhs is_static rhs_fvs (mkSRT lv_info) bndr_info new_rhs, rhs_fvs) where - binder_info = lookupFVInfo scope_fv_info binder + bndr_info = lookupFVInfo scope_fv_info bndr + is_static = rhsIsStatic hmods rhs -bogus_rhs = StgRhsClosure noCCS noBinderInfo [] ReEntrant [] bogus_expr -bogus_expr = (StgLit (MachInt 1)) +mkTopStgRhs :: Bool -> FreeVarsInfo -> SRT -> StgBinderInfo -> StgExpr + -> StgRhs -mkStgRhs :: TopLevelFlag -> FreeVarsInfo -> StgBinderInfo - -> StgExpr -> StgRhs - -mkStgRhs top rhs_fvs binder_info (StgLam _ bndrs body) - = StgRhsClosure noCCS binder_info +mkTopStgRhs is_static rhs_fvs srt binder_info (StgLam _ bndrs body) + = ASSERT( is_static ) + StgRhsClosure noCCS binder_info (getFVs rhs_fvs) ReEntrant + srt bndrs body -mkStgRhs top rhs_fvs binder_info (StgConApp con args) - | isNotTopLevel top || not (isDllConApp con args) +mkTopStgRhs is_static rhs_fvs srt binder_info (StgConApp con args) + | is_static -- StgConApps can be updatable (see isCrossDllConApp) = StgRhsCon noCCS con args -mkStgRhs top rhs_fvs binder_info rhs - = StgRhsClosure noCCS binder_info +mkTopStgRhs is_static rhs_fvs srt binder_info rhs + = ASSERT2( not is_static, ppr rhs ) + StgRhsClosure noCCS binder_info (getFVs rhs_fvs) - (updatable [] rhs) + Updatable + srt [] rhs - where - updatable args body | null args && isPAP body = ReEntrant - | otherwise = Updatable -{- ToDo: - upd = if isOnceDem dem - then (if isNotTop toplev - then SingleEntry -- HA! Paydirt for "dem" - else -#ifdef DEBUG - trace "WARNING: SE CAFs unsupported, forcing UPD instead" $ -#endif - Updatable) - else Updatable - -- For now we forbid SingleEntry CAFs; they tickle the - -- ASSERT in rts/Storage.c line 215 at newCAF() re mut_link, - -- and I don't understand why. There's only one SE_CAF (well, - -- only one that tickled a great gaping bug in an earlier attempt - -- at ClosureInfo.getEntryConvention) in the whole of nofib, - -- specifically Main.lvl6 in spectral/cryptarithm2. - -- So no great loss. KSW 2000-07. --} -\end{code} - -Detect thunks which will reduce immediately to PAPs, and make them -non-updatable. This has several advantages: - - - the non-updatable thunk behaves exactly like the PAP, - - - the thunk is more efficient to enter, because it is - specialised to the task. - - - we save one update frame, one stg_update_PAP, one update - and lots of PAP_enters. - - - in the case where the thunk is top-level, we save building - a black hole and futhermore the thunk isn't considered to - be a CAF any more, so it doesn't appear in any SRTs. - -We do it here, because the arity information is accurate, and we need -to do it before the SRT pass to save the SRT entries associated with -any top-level PAPs. - -\begin{code} -isPAP (StgApp f args) = idArity f > length args -isPAP _ = False \end{code} @@ -331,15 +302,15 @@ coreToStgExpr expr@(App _ _) (f, args) = myCollectArgs expr coreToStgExpr expr@(Lam _ _) - = let (args, body) = myCollectBinders expr + = let + (args, body) = myCollectBinders expr args' = filterStgBinders args in extendVarEnvLne [ (a, LambdaBound) | a <- args' ] $ coreToStgExpr body `thenLne` \ (body, body_fvs, body_escs) -> let - set_of_args = mkVarSet args' fvs = args' `minusFVBinders` body_fvs - escs = body_escs `minusVarSet` set_of_args + escs = body_escs `delVarSetList` args' result_expr | null args' = body | otherwise = StgLam (exprType expr) args' body in @@ -349,112 +320,81 @@ coreToStgExpr (Note (SCC cc) expr) = coreToStgExpr expr `thenLne` ( \ (expr2, fvs, escs) -> returnLne (StgSCC cc expr2, fvs, escs) ) +#ifdef ILX +-- For ILX, convert (__coerce__ to_ty from_ty e) +-- into (coerce to_ty from_ty e) +-- where coerce is real function +coreToStgExpr (Note (Coerce to_ty from_ty) expr) + = coreToStgExpr (mkApps (Var unsafeCoerceId) + [Type from_ty, Type to_ty, expr]) +#endif + coreToStgExpr (Note other_note expr) = coreToStgExpr expr - -- Cases require a little more real work. -coreToStgExpr (Case scrut bndr alts) - = extendVarEnvLne [(bndr, CaseBound)] $ - vars_alts (findDefault alts) `thenLne` \ (alts2, alts_fvs, alts_escs) -> - freeVarsToLiveVars alts_fvs `thenLne` \ (alts_lvs, alts_caf_refs) -> +coreToStgExpr (Case scrut bndr _ alts) + = extendVarEnvLne [(bndr, LambdaBound)] ( + mapAndUnzip3Lne vars_alt alts `thenLne` \ (alts2, fvs_s, escs_s) -> + returnLne ( alts2, + unionFVInfos fvs_s, + unionVarSets escs_s ) + ) `thenLne` \ (alts2, alts_fvs, alts_escs) -> let - -- determine whether the default binder is dead or not + -- Determine whether the default binder is dead or not -- This helps the code generator to avoid generating an assignment -- for the case binder (is extremely rare cases) ToDo: remove. - bndr'= if (bndr `elementOfFVInfo` alts_fvs) - then bndr - else bndr `setIdOccInfo` IAmDead + bndr' | bndr `elementOfFVInfo` alts_fvs = bndr + | otherwise = bndr `setIdOccInfo` IAmDead -- Don't consider the default binder as being 'live in alts', -- since this is from the point of view of the case expr, where -- the default binder is not free. - live_in_alts = (alts_lvs `minusVarSet` unitVarSet bndr) + alts_fvs_wo_bndr = bndr `minusFVBinder` alts_fvs + alts_escs_wo_bndr = alts_escs `delVarSet` bndr in - -- we tell the scrutinee that everything live in the alts - -- is live in it, too. - setVarsLiveInCont (live_in_alts,alts_caf_refs) ( + + freeVarsToLiveVars alts_fvs_wo_bndr `thenLne` \ alts_lv_info -> + + -- We tell the scrutinee that everything + -- live in the alts is live in it, too. + setVarsLiveInCont alts_lv_info ( coreToStgExpr scrut `thenLne` \ (scrut2, scrut_fvs, scrut_escs) -> - freeVarsToLiveVars scrut_fvs `thenLne` \ (scrut_lvs, _) -> - returnLne (scrut2, scrut_fvs, scrut_escs, scrut_lvs) + freeVarsToLiveVars scrut_fvs `thenLne` \ scrut_lv_info -> + returnLne (scrut2, scrut_fvs, scrut_escs, scrut_lv_info) ) - `thenLne` \ (scrut2, scrut_fvs, scrut_escs, scrut_lvs) -> + `thenLne` \ (scrut2, scrut_fvs, scrut_escs, scrut_lv_info) -> - let srt = SRTEntries alts_caf_refs - in returnLne ( - StgCase scrut2 scrut_lvs live_in_alts bndr' srt alts2, - bndr `minusFVBinder` (scrut_fvs `unionFVInfo` alts_fvs), - (alts_escs `minusVarSet` unitVarSet bndr) `unionVarSet` getFVSet scrut_fvs + StgCase scrut2 (getLiveVars scrut_lv_info) + (getLiveVars alts_lv_info) + bndr' + (mkSRT alts_lv_info) + (mkStgAltType (idType bndr) alts) + alts2, + scrut_fvs `unionFVInfo` alts_fvs_wo_bndr, + alts_escs_wo_bndr `unionVarSet` getFVSet scrut_fvs -- You might think we should have scrut_escs, not -- (getFVSet scrut_fvs), but actually we can't call, and -- then return from, a let-no-escape thing. ) where - scrut_ty = idType bndr - prim_case = isUnLiftedType scrut_ty && not (isUnboxedTupleType scrut_ty) - - vars_alts (alts,deflt) - | prim_case - = mapAndUnzip3Lne vars_prim_alt alts - `thenLne` \ (alts2, alts_fvs_list, alts_escs_list) -> - let - alts_fvs = unionFVInfos alts_fvs_list - alts_escs = unionVarSets alts_escs_list - in - vars_deflt deflt `thenLne` \ (deflt2, deflt_fvs, deflt_escs) -> - returnLne ( - mkStgPrimAlts scrut_ty alts2 deflt2, - alts_fvs `unionFVInfo` deflt_fvs, - alts_escs `unionVarSet` deflt_escs - ) - - | otherwise - = mapAndUnzip3Lne vars_alg_alt alts - `thenLne` \ (alts2, alts_fvs_list, alts_escs_list) -> - let - alts_fvs = unionFVInfos alts_fvs_list - alts_escs = unionVarSets alts_escs_list - in - vars_deflt deflt `thenLne` \ (deflt2, deflt_fvs, deflt_escs) -> - returnLne ( - mkStgAlgAlts scrut_ty alts2 deflt2, - alts_fvs `unionFVInfo` deflt_fvs, - alts_escs `unionVarSet` deflt_escs - ) - - where - vars_prim_alt (LitAlt lit, _, rhs) - = coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) -> - returnLne ((lit, rhs2), rhs_fvs, rhs_escs) - - vars_alg_alt (DataAlt con, binders, rhs) - = let - -- remove type variables - binders' = filterStgBinders binders - in - extendVarEnvLne [(b, CaseBound) | b <- binders'] $ - coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) -> - let - good_use_mask = [ b `elementOfFVInfo` rhs_fvs | b <- binders' ] - -- records whether each param is used in the RHS - in - returnLne ( - (con, binders', good_use_mask, rhs2), - binders' `minusFVBinders` rhs_fvs, - rhs_escs `minusVarSet` mkVarSet binders' - -- ToDo: remove the minusVarSet; - -- since escs won't include any of these binders - ) - vars_alg_alt other = pprPanic "vars_alg_alt" (ppr other) - - vars_deflt Nothing - = returnLne (StgNoDefault, emptyFVInfo, emptyVarSet) - - vars_deflt (Just rhs) - = coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) -> - returnLne (StgBindDefault rhs2, rhs_fvs, rhs_escs) + vars_alt (con, binders, rhs) + = let -- Remove type variables + binders' = filterStgBinders binders + in + extendVarEnvLne [(b, LambdaBound) | b <- binders'] $ + coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) -> + let + -- Records whether each param is used in the RHS + good_use_mask = [ b `elementOfFVInfo` rhs_fvs | b <- binders' ] + in + returnLne ( (con, binders', good_use_mask, rhs2), + binders' `minusFVBinders` rhs_fvs, + rhs_escs `delVarSetList` binders' ) + -- ToDo: remove the delVarSet; + -- since escs won't include any of these binders \end{code} Lets not only take quite a bit of work, but this is where we convert @@ -470,36 +410,30 @@ coreToStgExpr (Let bind body) returnLne (new_let, fvs, escs) \end{code} -If we've got a case containing a _ccall_GC_ primop, we need to -ensure that the arguments are kept live for the duration of the -call. This only an issue - \begin{code} -isForeignObjArg :: Id -> Bool -isForeignObjArg x = isId x && isForeignObjPrimTy (idType x) +mkStgAltType scrut_ty alts + = case splitTyConApp_maybe (repType scrut_ty) of + Just (tc,_) | isUnboxedTupleTyCon tc -> UbxTupAlt tc + | isPrimTyCon tc -> PrimAlt tc + | isHiBootTyCon tc -> look_for_better_tycon + | isAlgTyCon tc -> AlgAlt tc + | isFunTyCon tc -> PolyAlt + | otherwise -> pprPanic "mkStgAlts" (ppr tc) + Nothing -> PolyAlt -isForeignObjPrimTy ty - = case splitTyConApp_maybe ty of - Just (tycon, _) -> tycon == foreignObjPrimTyCon - Nothing -> False -\end{code} - -\begin{code} -mkStgAlgAlts ty alts deflt - = case alts of - -- Get the tycon from the data con - (dc, _, _, _) : _rest - -> StgAlgAlts (Just (dataConTyCon dc)) alts deflt - - -- Otherwise just do your best - [] -> case splitTyConApp_maybe (repType ty) of - Just (tc,_) | isAlgTyCon tc - -> StgAlgAlts (Just tc) alts deflt - other - -> StgAlgAlts Nothing alts deflt - -mkStgPrimAlts ty alts deflt - = StgPrimAlts (tyConAppTyCon ty) alts deflt + where + -- Sometimes, the TyCon in the type of the scrutinee is an HiBootTyCon, + -- which may not have any constructors inside it. If so, then we + -- can get a better TyCon by grabbing the one from a constructor alternative + -- if one exists. + look_for_better_tycon + | ((DataAlt con, _, _) : _) <- data_alts = + AlgAlt (dataConTyCon con) + | otherwise = + ASSERT(null data_alts) + PolyAlt + where + (data_alts, _deflt) = findDefault alts \end{code} @@ -522,9 +456,16 @@ coreToStgApp maybe_thunk_body f args lookupVarLne f `thenLne` \ how_bound -> let - n_args = length args + n_val_args = valArgCount args not_letrec_bound = not (isLetBound how_bound) - fun_fvs = singletonFVInfo f how_bound fun_occ + fun_fvs + = let fvs = singletonFVInfo f how_bound fun_occ in + -- e.g. (f :: a -> int) (x :: a) + -- Here the free variables are "f", "x" AND the type variable "a" + -- coreToStgArgs will deal with the arguments recursively + if opt_RuntimeTypes then + fvs `unionFVInfo` tyvarFVInfo (tyVarsOfType (idType f)) + else fvs -- Mostly, the arity info of a function is in the fn's IdInfo -- But new bindings introduced by CoreSat may not have no @@ -532,18 +473,18 @@ coreToStgApp maybe_thunk_body f args -- let f = \ab -> e in f -- No point in having correct arity info for f! -- Hence the hasArity stuff below. - f_arity = case how_bound of - LetBound _ _ arity -> arity - _ -> 0 + -- NB: f_arity is only consulted for LetBound things + f_arity = stgArity f how_bound + saturated = f_arity <= n_val_args fun_occ - | not_letrec_bound = noBinderInfo -- Uninteresting variable - | f_arity > 0 && f_arity <= n_args = stgSatOcc -- Saturated or over-saturated function call - | otherwise = stgUnsatOcc -- Unsaturated function or thunk + | not_letrec_bound = noBinderInfo -- Uninteresting variable + | f_arity > 0 && saturated = stgSatOcc -- Saturated or over-saturated function call + | otherwise = stgUnsatOcc -- Unsaturated function or thunk fun_escs - | not_letrec_bound = emptyVarSet -- Only letrec-bound escapees are interesting - | f_arity == n_args = emptyVarSet -- A function *or thunk* with an exactly + | not_letrec_bound = emptyVarSet -- Only letrec-bound escapees are interesting + | f_arity == n_val_args = emptyVarSet -- A function *or thunk* with an exactly -- saturated call doesn't escape -- (let-no-escape applies to 'thunks' too) @@ -560,10 +501,14 @@ coreToStgApp maybe_thunk_body f args -- continuation, but it does no harm to just union the -- two regardless. + res_ty = exprType (mkApps (Var f) args) app = case globalIdDetails f of - DataConId dc -> StgConApp dc args' - PrimOpId op -> StgPrimApp op args' (exprType (mkApps (Var f) args)) - _other -> StgApp f args' + DataConWorkId dc | saturated -> StgConApp dc args' + PrimOpId op -> ASSERT( saturated ) + StgOpApp (StgPrimOp op) args' res_ty + FCallId call -> ASSERT( saturated ) + StgOpApp (StgFCallOp call (idUnique f)) args' res_ty + _other -> StgApp f args' in returnLne ( @@ -587,7 +532,7 @@ coreToStgArgs [] coreToStgArgs (Type ty : args) -- Type argument = coreToStgArgs args `thenLne` \ (args', fvs) -> - if opt_KeepStgTypes then + if opt_RuntimeTypes then returnLne (StgTypeArg ty : args', fvs `unionFVInfo` tyvarFVInfo (tyVarsOfType ty)) else returnLne (args', fvs) @@ -599,7 +544,7 @@ coreToStgArgs (arg : args) -- Non-type argument fvs = args_fvs `unionFVInfo` arg_fvs stg_arg = case arg' of StgApp v [] -> StgVarArg v - StgConApp con [] -> StgVarArg (dataConWrapId con) + StgConApp con [] -> StgVarArg (dataConWorkId con) StgLit lit -> StgLitArg lit _ -> pprPanic "coreToStgArgs" (ppr arg) in @@ -628,20 +573,20 @@ coreToStgLet let_no_escape bind body getVarsLiveInCont `thenLne` \ live_in_cont -> setVarsLiveInCont (if let_no_escape then live_in_cont - else (emptyVarSet,emptyVarSet)) + else emptyLiveInfo) (vars_bind rec_body_fvs bind) - `thenLne` \ (bind2, bind_fvs, bind_escs, bind_lvs, env_ext) -> + `thenLne` \ ( bind2, bind_fvs, bind_escs, bind_lv_info, env_ext) -> -- Do the body extendVarEnvLne env_ext ( coreToStgExpr body `thenLne` \(body2, body_fvs, body_escs) -> - freeVarsToLiveVars body_fvs `thenLne` \(body_lvs, _) -> + freeVarsToLiveVars body_fvs `thenLne` \ body_lv_info -> - returnLne (bind2, bind_fvs, bind_escs, bind_lvs, - body2, body_fvs, body_escs, body_lvs) + returnLne (bind2, bind_fvs, bind_escs, getLiveVars bind_lv_info, + body2, body_fvs, body_escs, getLiveVars body_lv_info) ) - ) `thenLne` (\ (bind2, bind_fvs, bind_escs, bind_lvs, + ) `thenLne` (\ (bind2, bind_fvs, bind_escs, bind_lvs, body2, body_fvs, body_escs, body_lvs) -> @@ -654,7 +599,7 @@ coreToStgLet let_no_escape bind body = binders `minusFVBinders` (bind_fvs `unionFVInfo` body_fvs) live_in_whole_let - = bind_lvs `unionVarSet` (body_lvs `minusVarSet` set_of_binders) + = bind_lvs `unionVarSet` (body_lvs `delVarSetList` binders) real_bind_escs = if let_no_escape then bind_escs @@ -662,7 +607,7 @@ coreToStgLet let_no_escape bind body getFVSet bind_fvs -- Everything escapes which is free in the bindings - let_escs = (real_bind_escs `unionVarSet` body_escs) `minusVarSet` set_of_binders + let_escs = (real_bind_escs `unionVarSet` body_escs) `delVarSetList` binders all_escs = bind_escs `unionVarSet` body_escs -- Still includes binders of -- this let(rec) @@ -691,68 +636,147 @@ coreToStgLet let_no_escape bind body )) where set_of_binders = mkVarSet binders - binders = case bind of - NonRec binder rhs -> [binder] - Rec pairs -> map fst pairs + binders = bindersOf bind - mk_binding bind_lvs binder rhs - = (binder, LetBound NotTopLevelBound -- Not top level - live_vars (exprArity rhs) - ) + mk_binding bind_lv_info binder rhs + = (binder, LetBound (NestedLet live_vars) (manifestArity rhs)) where - live_vars = if let_no_escape then - extendVarSet bind_lvs binder - else - unitVarSet binder + live_vars | let_no_escape = addLiveVar bind_lv_info binder + | otherwise = unitLiveVar binder + -- c.f. the invariant on NestedLet vars_bind :: FreeVarsInfo -- Free var info for body of binding -> CoreBind -> LneM (StgBinding, FreeVarsInfo, EscVarsSet, -- free vars; escapee vars - StgLiveVars, -- vars live in binding + LiveInfo, -- Vars and CAFs live in binding [(Id, HowBound)]) -- extension to environment vars_bind body_fvs (NonRec binder rhs) - = coreToStgRhs body_fvs NotTopLevel (binder,rhs) - `thenLne` \ (rhs2, bind_fvs, escs) -> - - freeVarsToLiveVars bind_fvs `thenLne` \ (bind_lvs, bind_cafs) -> + = coreToStgRhs body_fvs [] (binder,rhs) + `thenLne` \ (rhs2, bind_fvs, bind_lv_info, escs) -> let - env_ext_item@(binder', _) = mk_binding bind_lvs binder rhs + env_ext_item = mk_binding bind_lv_info binder rhs in - returnLne (StgNonRec (SRTEntries bind_cafs) binder' rhs2, - bind_fvs, escs, bind_lvs, [env_ext_item]) + returnLne (StgNonRec binder rhs2, + bind_fvs, escs, bind_lv_info, [env_ext_item]) vars_bind body_fvs (Rec pairs) - = fixLne (\ ~(_, rec_rhs_fvs, _, bind_lvs, _) -> + = fixLne (\ ~(_, rec_rhs_fvs, _, bind_lv_info, _) -> let rec_scope_fvs = unionFVInfo body_fvs rec_rhs_fvs binders = map fst pairs - env_ext = [ mk_binding bind_lvs b rhs | (b,rhs) <- pairs ] + env_ext = [ mk_binding bind_lv_info b rhs + | (b,rhs) <- pairs ] in extendVarEnvLne env_ext ( - mapAndUnzip3Lne (coreToStgRhs rec_scope_fvs NotTopLevel) pairs - `thenLne` \ (rhss2, fvss, escss) -> + mapAndUnzip4Lne (coreToStgRhs rec_scope_fvs binders) pairs + `thenLne` \ (rhss2, fvss, lv_infos, escss) -> let bind_fvs = unionFVInfos fvss + bind_lv_info = foldr unionLiveInfo emptyLiveInfo lv_infos escs = unionVarSets escss in - freeVarsToLiveVars (binders `minusFVBinders` bind_fvs) - `thenLne` \ (bind_lvs, bind_cafs) -> - returnLne (StgRec (SRTEntries bind_cafs) (binders `zip` rhss2), - bind_fvs, escs, bind_lvs, env_ext) + returnLne (StgRec (binders `zip` rhss2), + bind_fvs, escs, bind_lv_info, env_ext) ) ) is_join_var :: Id -> Bool -- A hack (used only for compiler debuggging) to tell if -- a variable started life as a join point ($j) -is_join_var j = occNameUserString (getOccName j) == "$j" +is_join_var j = occNameString (getOccName j) == "$j" \end{code} +\begin{code} +coreToStgRhs :: FreeVarsInfo -- Free var info for the scope of the binding + -> [Id] + -> (Id,CoreExpr) + -> LneM (StgRhs, FreeVarsInfo, LiveInfo, EscVarsSet) + +coreToStgRhs scope_fv_info binders (bndr, rhs) + = coreToStgExpr rhs `thenLne` \ (new_rhs, rhs_fvs, rhs_escs) -> + getEnvLne `thenLne` \ env -> + freeVarsToLiveVars (binders `minusFVBinders` rhs_fvs) `thenLne` \ lv_info -> + returnLne (mkStgRhs rhs_fvs (mkSRT lv_info) bndr_info new_rhs, + rhs_fvs, lv_info, rhs_escs) + where + bndr_info = lookupFVInfo scope_fv_info bndr + +mkStgRhs :: FreeVarsInfo -> SRT -> StgBinderInfo -> StgExpr -> StgRhs + +mkStgRhs rhs_fvs srt binder_info (StgConApp con args) + = StgRhsCon noCCS con args + +mkStgRhs rhs_fvs srt binder_info (StgLam _ bndrs body) + = StgRhsClosure noCCS binder_info + (getFVs rhs_fvs) + ReEntrant + srt bndrs body + +mkStgRhs rhs_fvs srt binder_info rhs + = StgRhsClosure noCCS binder_info + (getFVs rhs_fvs) + upd_flag srt [] rhs + where + upd_flag = Updatable + {- + SDM: disabled. Eval/Apply can't handle functions with arity zero very + well; and making these into simple non-updatable thunks breaks other + assumptions (namely that they will be entered only once). + + upd_flag | isPAP env rhs = ReEntrant + | otherwise = Updatable + -} + +{- ToDo: + upd = if isOnceDem dem + then (if isNotTop toplev + then SingleEntry -- HA! Paydirt for "dem" + else +#ifdef DEBUG + trace "WARNING: SE CAFs unsupported, forcing UPD instead" $ +#endif + Updatable) + else Updatable + -- For now we forbid SingleEntry CAFs; they tickle the + -- ASSERT in rts/Storage.c line 215 at newCAF() re mut_link, + -- and I don't understand why. There's only one SE_CAF (well, + -- only one that tickled a great gaping bug in an earlier attempt + -- at ClosureInfo.getEntryConvention) in the whole of nofib, + -- specifically Main.lvl6 in spectral/cryptarithm2. + -- So no great loss. KSW 2000-07. +-} +\end{code} + +Detect thunks which will reduce immediately to PAPs, and make them +non-updatable. This has several advantages: + + - the non-updatable thunk behaves exactly like the PAP, + + - the thunk is more efficient to enter, because it is + specialised to the task. + + - we save one update frame, one stg_update_PAP, one update + and lots of PAP_enters. + + - in the case where the thunk is top-level, we save building + a black hole and futhermore the thunk isn't considered to + be a CAF any more, so it doesn't appear in any SRTs. + +We do it here, because the arity information is accurate, and we need +to do it before the SRT pass to save the SRT entries associated with +any top-level PAPs. + +isPAP env (StgApp f args) = listLengthCmp args arity == LT -- idArity f > length args + where + arity = stgArity f (lookupBinding env f) +isPAP env _ = False + + %************************************************************************ %* * \subsection[LNE-monad]{A little monad for this let-no-escaping pass} @@ -764,38 +788,86 @@ help. All the stuff here is only passed *down*. \begin{code} type LneM a = IdEnv HowBound - -> (StgLiveVars, -- vars live in continuation - IdSet) -- cafs live in continuation + -> LiveInfo -- Vars and CAFs live in continuation -> a +type LiveInfo = (StgLiveVars, -- Dynamic live variables; + -- i.e. ones with a nested (non-top-level) binding + CafSet) -- Static live variables; + -- i.e. top-level variables that are CAFs or refer to them + +type EscVarsSet = IdSet +type CafSet = IdSet + data HowBound - = ImportBound - | CaseBound - | LambdaBound - | LetBound - TopLevelCafInfo - StgLiveVars -- Live vars... see notes below - Arity -- its arity (local Ids don't have arity info at this point) - -isLetBound (LetBound _ _ _) = True -isLetBound other = False + = ImportBound -- Used only as a response to lookupBinding; never + -- exists in the range of the (IdEnv HowBound) + + | LetBound -- A let(rec) in this module + LetInfo -- Whether top level or nested + Arity -- Its arity (local Ids don't have arity info at this point) + + | LambdaBound -- Used for both lambda and case + +data LetInfo + = TopLet -- top level things + | NestedLet LiveInfo -- For nested things, what is live if this + -- thing is live? Invariant: the binder + -- itself is always a member of + -- the dynamic set of its own LiveInfo + +isLetBound (LetBound _ _) = True +isLetBound other = False + +topLevelBound ImportBound = True +topLevelBound (LetBound TopLet _) = True +topLevelBound other = False \end{code} -For a let(rec)-bound variable, x, we record StgLiveVars, the set of -variables that are live if x is live. For "normal" variables that is -just x alone. If x is a let-no-escaped variable then x is represented -by a code pointer and a stack pointer (well, one for each stack). So -all of the variables needed in the execution of x are live if x is, -and are therefore recorded in the LetBound constructor; x itself -*is* included. +For a let(rec)-bound variable, x, we record LiveInfo, the set of +variables that are live if x is live. This LiveInfo comprises + (a) dynamic live variables (ones with a non-top-level binding) + (b) static live variabes (CAFs or things that refer to CAFs) + +For "normal" variables (a) is just x alone. If x is a let-no-escaped +variable then x is represented by a code pointer and a stack pointer +(well, one for each stack). So all of the variables needed in the +execution of x are live if x is, and are therefore recorded in the +LetBound constructor; x itself *is* included. -The set of live variables is guaranteed ot have no further let-no-escaped +The set of dynamic live variables is guaranteed ot have no further let-no-escaped variables in it. +\begin{code} +emptyLiveInfo :: LiveInfo +emptyLiveInfo = (emptyVarSet,emptyVarSet) + +unitLiveVar :: Id -> LiveInfo +unitLiveVar lv = (unitVarSet lv, emptyVarSet) + +unitLiveCaf :: Id -> LiveInfo +unitLiveCaf caf = (emptyVarSet, unitVarSet caf) + +addLiveVar :: LiveInfo -> Id -> LiveInfo +addLiveVar (lvs, cafs) id = (lvs `extendVarSet` id, cafs) + +unionLiveInfo :: LiveInfo -> LiveInfo -> LiveInfo +unionLiveInfo (lv1,caf1) (lv2,caf2) = (lv1 `unionVarSet` lv2, caf1 `unionVarSet` caf2) + +mkSRT :: LiveInfo -> SRT +mkSRT (_, cafs) = SRTEntries cafs + +getLiveVars :: LiveInfo -> StgLiveVars +getLiveVars (lvs, _) = lvs +\end{code} + + The std monad functions: \begin{code} initLne :: IdEnv HowBound -> LneM a -> a -initLne env m = m env (emptyVarSet,emptyVarSet) +initLne env m = m env emptyLiveInfo + + {-# INLINE thenLne #-} {-# INLINE returnLne #-} @@ -807,15 +879,7 @@ thenLne :: LneM a -> (a -> LneM b) -> LneM b thenLne m k env lvs_cont = k (m env lvs_cont) env lvs_cont -mapLne :: (a -> LneM b) -> [a] -> LneM [b] -mapLne f [] = returnLne [] -mapLne f (x:xs) - = f x `thenLne` \ r -> - mapLne f xs `thenLne` \ rs -> - returnLne (r:rs) - mapAndUnzipLne :: (a -> LneM (b,c)) -> [a] -> LneM ([b],[c]) - mapAndUnzipLne f [] = returnLne ([],[]) mapAndUnzipLne f (x:xs) = f x `thenLne` \ (r1, r2) -> @@ -823,13 +887,19 @@ mapAndUnzipLne f (x:xs) returnLne (r1:rs1, r2:rs2) mapAndUnzip3Lne :: (a -> LneM (b,c,d)) -> [a] -> LneM ([b],[c],[d]) - mapAndUnzip3Lne f [] = returnLne ([],[],[]) mapAndUnzip3Lne f (x:xs) = f x `thenLne` \ (r1, r2, r3) -> mapAndUnzip3Lne f xs `thenLne` \ (rs1, rs2, rs3) -> returnLne (r1:rs1, r2:rs2, r3:rs3) +mapAndUnzip4Lne :: (a -> LneM (b,c,d,e)) -> [a] -> LneM ([b],[c],[d],[e]) +mapAndUnzip4Lne f [] = returnLne ([],[],[],[]) +mapAndUnzip4Lne f (x:xs) + = f x `thenLne` \ (r1, r2, r3, r4) -> + mapAndUnzip4Lne f xs `thenLne` \ (rs1, rs2, rs3, rs4) -> + returnLne (r1:rs1, r2:rs2, r3:rs3, r4:rs4) + fixLne :: (a -> LneM a) -> LneM a fixLne expr env lvs_cont = result @@ -840,10 +910,10 @@ fixLne expr env lvs_cont Functions specific to this monad: \begin{code} -getVarsLiveInCont :: LneM (StgLiveVars, IdSet) +getVarsLiveInCont :: LneM LiveInfo getVarsLiveInCont env lvs_cont = lvs_cont -setVarsLiveInCont :: (StgLiveVars,IdSet) -> LneM a -> LneM a +setVarsLiveInCont :: LiveInfo -> LneM a -> LneM a setVarsLiveInCont new_lvs_cont expr env lvs_cont = expr env new_lvs_cont @@ -852,44 +922,40 @@ extendVarEnvLne ids_w_howbound expr env lvs_cont = expr (extendVarEnvList env ids_w_howbound) lvs_cont lookupVarLne :: Id -> LneM HowBound -lookupVarLne v env lvs_cont - = returnLne ( - case (lookupVarEnv env v) of - Just xx -> xx - Nothing -> ImportBound - ) env lvs_cont +lookupVarLne v env lvs_cont = returnLne (lookupBinding env v) env lvs_cont + +getEnvLne :: LneM (IdEnv HowBound) +getEnvLne env lvs_cont = returnLne env env lvs_cont + +lookupBinding :: IdEnv HowBound -> Id -> HowBound +lookupBinding env v = case lookupVarEnv env v of + Just xx -> xx + Nothing -> ASSERT2( isGlobalId v, ppr v ) ImportBound + -- The result of lookupLiveVarsForSet, a set of live variables, is -- only ever tacked onto a decorated expression. It is never used as -- the basis of a control decision, which might give a black hole. -freeVarsToLiveVars :: FreeVarsInfo -> LneM (StgLiveVars, IdSet) +freeVarsToLiveVars :: FreeVarsInfo -> LneM LiveInfo freeVarsToLiveVars fvs env live_in_cont - = returnLne (lvs `unionVarSet` lvs_cont, - mkVarSet cafs `unionVarSet` cafs_cont) - env live_in_cont + = returnLne live_info env live_in_cont where - (lvs_cont, cafs_cont) = live_in_cont -- not a strict pattern match! - (local, global) = partition isLocalId (allFVs fvs) - - cafs = filter is_caf_one global - lvs = unionVarSets (map do_one local) - - do_one v - = if isLocalId v then - case (lookupVarEnv env v) of - Just (LetBound _ lvs _) -> extendVarSet lvs v - Just _ -> unitVarSet v - Nothing -> pprPanic "lookupLiveVarsForSet/do_one:" (ppr v) - else - emptyVarSet - - is_caf_one v - = case lookupVarEnv env v of - Just (LetBound TopLevelHasCafs lvs _) -> - ASSERT( isEmptyVarSet lvs ) True - Just (LetBound _ _ _) -> False - _otherwise -> mayHaveCafRefs (idCafInfo v) + live_info = foldr unionLiveInfo live_in_cont lvs_from_fvs + lvs_from_fvs = map do_one (allFreeIds fvs) + + do_one (v, how_bound) + = case how_bound of + ImportBound -> unitLiveCaf v -- Only CAF imports are + -- recorded in fvs + LetBound TopLet _ + | mayHaveCafRefs (idCafInfo v) -> unitLiveCaf v + | otherwise -> emptyLiveInfo + + LetBound (NestedLet lvs) _ -> lvs -- lvs already contains v + -- (see the invariant on NestedLet) + + _lambda_or_case_binding -> unitLiveVar v -- Bound by lambda or case \end{code} %************************************************************************ @@ -899,7 +965,21 @@ freeVarsToLiveVars fvs env live_in_cont %************************************************************************ \begin{code} -type FreeVarsInfo = VarEnv (Var, TopLevelCafInfo, StgBinderInfo) +type FreeVarsInfo = VarEnv (Var, HowBound, StgBinderInfo) + -- The Var is so we can gather up the free variables + -- as a set. + -- + -- The HowBound info just saves repeated lookups; + -- we look up just once when we encounter the occurrence. + -- INVARIANT: Any ImportBound Ids are HaveCafRef Ids + -- Imported Ids without CAF refs are simply + -- not put in the FreeVarsInfo for an expression. + -- See singletonFVInfo and freeVarsToLiveVars + -- + -- StgBinderInfo records how it occurs; notably, we + -- are interested in whether it only occurs in saturated + -- applications, because then we don't need to build a + -- curried version. -- If f is mapped to noBinderInfo, that means -- that f *is* mentioned (else it wouldn't be in the -- IdEnv at all), but perhaps in an unsaturated applications. @@ -910,14 +990,6 @@ type FreeVarsInfo = VarEnv (Var, TopLevelCafInfo, StgBinderInfo) -- -- For ILX we track free var info for type variables too; -- hence VarEnv not IdEnv - -data TopLevelCafInfo - = NotTopLevelBound - | TopLevelNoCafs - | TopLevelHasCafs - deriving Eq - -type EscVarsSet = IdSet \end{code} \begin{code} @@ -925,18 +997,17 @@ emptyFVInfo :: FreeVarsInfo emptyFVInfo = emptyVarEnv singletonFVInfo :: Id -> HowBound -> StgBinderInfo -> FreeVarsInfo +-- Don't record non-CAF imports at all, to keep free-var sets small singletonFVInfo id ImportBound info - | mayHaveCafRefs (idCafInfo id) = unitVarEnv id (id, TopLevelHasCafs, info) + | mayHaveCafRefs (idCafInfo id) = unitVarEnv id (id, ImportBound, info) | otherwise = emptyVarEnv -singletonFVInfo id (LetBound top_level _ _) info - = unitVarEnv id (id, top_level, info) -singletonFVInfo id other info - = unitVarEnv id (id, NotTopLevelBound, info) +singletonFVInfo id how_bound info = unitVarEnv id (id, how_bound, info) tyvarFVInfo :: TyVarSet -> FreeVarsInfo tyvarFVInfo tvs = foldVarSet add emptyFVInfo tvs where - add tv fvs = extendVarEnv fvs tv (tv, NotTopLevelBound, noBinderInfo) + add tv fvs = extendVarEnv fvs tv (tv, LambdaBound, noBinderInfo) + -- Type variables must be lambda-bound unionFVInfo :: FreeVarsInfo -> FreeVarsInfo -> FreeVarsInfo unionFVInfo fv1 fv2 = plusVarEnv_C plusFVInfo fv1 fv2 @@ -948,7 +1019,7 @@ minusFVBinders :: [Id] -> FreeVarsInfo -> FreeVarsInfo minusFVBinders vs fv = foldr minusFVBinder fv vs minusFVBinder :: Id -> FreeVarsInfo -> FreeVarsInfo -minusFVBinder v fv | isId v && opt_KeepStgTypes +minusFVBinder v fv | isId v && opt_RuntimeTypes = (fv `delVarEnv` v) `unionFVInfo` tyvarFVInfo (tyVarsOfType (idType v)) | otherwise = fv `delVarEnv` v @@ -962,30 +1033,45 @@ lookupFVInfo :: FreeVarsInfo -> Id -> StgBinderInfo -- Find how the given Id is used. -- Externally visible things may be used any old how lookupFVInfo fvs id - | isExternallyVisibleName (idName id) = noBinderInfo + | isExternalName (idName id) = noBinderInfo | otherwise = case lookupVarEnv fvs id of Nothing -> noBinderInfo Just (_,_,info) -> info -allFVs :: FreeVarsInfo -> [Id] -- Non-top-level things only -allFVs fvs = [id | (id,_,_) <- rngVarEnv fvs] +allFreeIds :: FreeVarsInfo -> [(Id,HowBound)] -- Both top level and non-top-level Ids +allFreeIds fvs = [(id,how_bound) | (id,how_bound,_) <- varEnvElts fvs, isId id] -getFVs :: FreeVarsInfo -> [Id] -- Non-top-level things only -getFVs fvs = [id | (id,NotTopLevelBound,_) <- rngVarEnv fvs] +-- Non-top-level things only, both type variables and ids +-- (type variables only if opt_RuntimeTypes) +getFVs :: FreeVarsInfo -> [Var] +getFVs fvs = [id | (id, how_bound, _) <- varEnvElts fvs, + not (topLevelBound how_bound) ] -getFVSet :: FreeVarsInfo -> IdSet +getFVSet :: FreeVarsInfo -> VarSet getFVSet fvs = mkVarSet (getFVs fvs) -plusFVInfo (id1,top1,info1) (id2,top2,info2) - = ASSERT (id1 == id2 && top1 == top2) - (id1, top1, combineStgBinderInfo info1 info2) +plusFVInfo (id1,hb1,info1) (id2,hb2,info2) + = ASSERT (id1 == id2 && hb1 `check_eq_how_bound` hb2) + (id1, hb1, combineStgBinderInfo info1 info2) + +#ifdef DEBUG +-- The HowBound info for a variable in the FVInfo should be consistent +check_eq_how_bound ImportBound ImportBound = True +check_eq_how_bound LambdaBound LambdaBound = True +check_eq_how_bound (LetBound li1 ar1) (LetBound li2 ar2) = ar1 == ar2 && check_eq_li li1 li2 +check_eq_how_bound hb1 hb2 = False + +check_eq_li (NestedLet _) (NestedLet _) = True +check_eq_li TopLet TopLet = True +check_eq_li li1 li2 = False +#endif \end{code} Misc. \begin{code} filterStgBinders :: [Var] -> [Var] filterStgBinders bndrs - | opt_KeepStgTypes = bndrs + | opt_RuntimeTypes = bndrs | otherwise = filter isId bndrs \end{code} @@ -1013,125 +1099,9 @@ myCollectArgs expr go _ as = pprPanic "CoreToStg.myCollectArgs" (ppr expr) \end{code} -%************************************************************************ -%* * -\subsection{Figuring out CafInfo for an expression} -%* * -%************************************************************************ - -hasCafRefs decides whether a top-level closure can point into the dynamic heap. -We mark such things as `MayHaveCafRefs' because this information is -used to decide whether a particular closure needs to be referenced -in an SRT or not. - -There are two reasons for setting MayHaveCafRefs: - a) The RHS is a CAF: a top-level updatable thunk. - b) The RHS refers to something that MayHaveCafRefs - -Possible improvement: In an effort to keep the number of CAFs (and -hence the size of the SRTs) down, we could also look at the expression and -decide whether it requires a small bounded amount of heap, so we can ignore -it as a CAF. In these cases however, we would need to use an additional -CAF list to keep track of non-collectable CAFs. - \begin{code} -hasCafRefs :: IdEnv HowBound -> CoreExpr -> CafInfo --- Only called for the RHS of top-level lets -hasCafRefss :: IdEnv HowBound -> [CoreExpr] -> CafInfo - -- predicate returns True for a given Id if we look at this Id when - -- calculating the result. Used to *avoid* looking at the CafInfo - -- field for an Id that is part of the current recursive group. - -hasCafRefs p expr - | isCAF expr || isFastTrue (cafRefs p expr) = MayHaveCafRefs - | otherwise = NoCafRefs - - -- used for recursive groups. The whole group is set to - -- "MayHaveCafRefs" if at least one of the group is a CAF or - -- refers to any CAFs. -hasCafRefss p exprs - | any isCAF exprs || isFastTrue (cafRefss p exprs) = MayHaveCafRefs - | otherwise = NoCafRefs - --- cafRefs compiles to beautiful code :) - -cafRefs p (Var id) - | isLocalId id = fastBool False - | otherwise = - case lookupVarEnv p id of - Just (LetBound TopLevelHasCafs _ _) -> fastBool True - Just (LetBound _ _ _) -> fastBool False - Nothing -> fastBool (cgMayHaveCafRefs (idCgInfo id)) -- imported Ids - -cafRefs p (Lit l) = fastBool False -cafRefs p (App f a) = fastOr (cafRefs p f) (cafRefs p) a -cafRefs p (Lam x e) = cafRefs p e -cafRefs p (Let b e) = fastOr (cafRefss p (rhssOfBind b)) (cafRefs p) e -cafRefs p (Case e bndr alts) = fastOr (cafRefs p e) - (cafRefss p) (rhssOfAlts alts) -cafRefs p (Note n e) = cafRefs p e -cafRefs p (Type t) = fastBool False - -cafRefss p [] = fastBool False -cafRefss p (e:es) = fastOr (cafRefs p e) (cafRefss p) es - --- hack for lazy-or over FastBool. -fastOr a f x = fastBool (isFastTrue a || isFastTrue (f x)) - -isCAF :: CoreExpr -> Bool --- Only called for the RHS of top-level lets -isCAF e = not (rhsIsNonUpd e) - {- ToDo: check type for onceness, i.e. non-updatable thunks? -} - - -rhsIsNonUpd :: CoreExpr -> Bool - -- True => Value-lambda, constructor, PAP - -- This is a bit like CoreUtils.exprIsValue, with the following differences: - -- a) scc "foo" (\x -> ...) is updatable (so we catch the right SCC) - -- - -- b) (C x xs), where C is a contructors is updatable if the application is - -- dynamic: see isDynConApp - -- - -- c) don't look through unfolding of f in (f x). I'm suspicious of this one - -rhsIsNonUpd (Lam b e) = isId b || rhsIsNonUpd e -rhsIsNonUpd (Note (SCC _) e) = False -rhsIsNonUpd (Note _ e) = rhsIsNonUpd e -rhsIsNonUpd other_expr - = go other_expr 0 [] - where - go (Var f) n_args args = idAppIsNonUpd f n_args args - - go (App f a) n_args args - | isTypeArg a = go f n_args args - | otherwise = go f (n_args + 1) (a:args) - - go (Note (SCC _) f) n_args args = False - go (Note _ f) n_args args = go f n_args args - - go other n_args args = False - -idAppIsNonUpd :: Id -> Int -> [CoreExpr] -> Bool -idAppIsNonUpd id n_val_args args - | Just con <- isDataConId_maybe id = not (isDynConApp con args) - | otherwise = n_val_args < idArity id - -isDynConApp :: DataCon -> [CoreExpr] -> Bool -isDynConApp con args = isDllName (dataConName con) || any isDynArg args --- Top-level constructor applications can usually be allocated --- statically, but they can't if --- a) the constructor, or any of the arguments, come from another DLL --- b) any of the arguments are LitLits --- (because we can't refer to static labels in other DLLs). --- If this happens we simply make the RHS into an updatable thunk, --- and 'exectute' it rather than allocating it statically. --- All this should match the decision in (see CoreToStg.coreToStgRhs) - - -isDynArg :: CoreExpr -> Bool -isDynArg (Var v) = isDllName (idName v) -isDynArg (Note _ e) = isDynArg e -isDynArg (Lit lit) = isLitLitLit lit -isDynArg (App e _) = isDynArg e -- must be a type app -isDynArg (Lam _ e) = isDynArg e -- must be a type lam +stgArity :: Id -> HowBound -> Arity +stgArity f (LetBound _ arity) = arity +stgArity f ImportBound = idArity f +stgArity f LambdaBound = 0 \end{code}