X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fspecialise%2FSpecialise.lhs;h=006e06d15e99605149e8463bec211c4137f20b67;hb=e6834cad29914f123edb32c20d42b16e3308e667;hp=bdef3523f6cddc9b93fcbd06edaf9964d5d46b73;hpb=12e6a9a58473f8b24e831c2171bf62d256da8a85;p=ghc-hetmet.git diff --git a/ghc/compiler/specialise/Specialise.lhs b/ghc/compiler/specialise/Specialise.lhs index bdef352..006e06d 100644 --- a/ghc/compiler/specialise/Specialise.lhs +++ b/ghc/compiler/specialise/Specialise.lhs @@ -9,43 +9,41 @@ module Specialise ( specProgram ) where #include "HsVersions.h" import CmdLineOpts ( DynFlags, DynFlag(..) ) -import Id ( Id, idName, idType, mkUserLocal, - idSpecialisation, modifyIdInfo +import Id ( Id, idName, idType, mkUserLocal ) +import TcType ( Type, mkTyVarTy, tcSplitSigmaTy, + tyVarsOfTypes, tyVarsOfTheta, isClassPred, + mkForAllTys, tcCmpType ) -import IdInfo ( zapSpecPragInfo ) -import VarSet -import VarEnv - -import Type ( Type, mkTyVarTy, splitSigmaTy, - tyVarsOfTypes, tyVarsOfTheta, - mkForAllTys - ) -import Subst ( Subst, mkSubst, substTy, mkSubst, substBndrs, extendSubstList, mkInScopeSet, - substId, substAndCloneId, substAndCloneIds, lookupIdSubst, substInScope +import Subst ( Subst, mkSubst, substTy, mkSubst, extendSubstList, mkInScopeSet, + simplBndr, simplBndrs, + substAndCloneId, substAndCloneIds, substAndCloneRecIds, + lookupIdSubst, substInScope ) +import Var ( zapSpecPragmaId ) import VarSet import VarEnv import CoreSyn import CoreUtils ( applyTypeToArgs ) -import CoreUnfold ( certainlyWillInline ) import CoreFVs ( exprFreeVars, exprsFreeVars ) +import CoreTidy ( pprTidyIdRules ) import CoreLint ( showPass, endPass ) -import PprCore ( pprCoreRules ) import Rules ( addIdSpecialisations, lookupRule ) import UniqSupply ( UniqSupply, - UniqSM, initUs_, thenUs, thenUs, returnUs, getUniqueUs, - withUs, mapUs + UniqSM, initUs_, thenUs, returnUs, getUniqueUs, + getUs, mapUs ) import Name ( nameOccName, mkSpecOcc, getSrcLoc ) import FiniteMap import Maybes ( catMaybes, maybeToBool ) import ErrUtils ( dumpIfSet_dyn ) +import BasicTypes ( Activation( AlwaysActive ) ) import Bag import List ( partition ) -import Util ( zipEqual, zipWithEqual ) +import Util ( zipEqual, zipWithEqual, cmpList, lengthIs, + equalLength, lengthAtLeast, notNull ) import Outputable - +import FastString infixr 9 `thenSM` \end{code} @@ -588,7 +586,7 @@ specProgram dflags us binds endPass dflags "Specialise" Opt_D_dump_spec binds' dumpIfSet_dyn dflags Opt_D_dump_rules "Top-level specialisations" - (vcat (map dump_specs (concat (map bindersOf binds')))) + (vcat (map pprTidyIdRules (concat (map bindersOf binds')))) return binds' where @@ -603,8 +601,6 @@ specProgram dflags us binds go (bind:binds) = go binds `thenSM` \ (binds', uds) -> specBind top_subst bind uds `thenSM` \ (bind', uds') -> returnSM (bind' ++ binds', uds') - -dump_specs var = pprCoreRules var (idSpecialisation var) \end{code} %************************************************************************ @@ -658,7 +654,7 @@ specExpr subst e@(Lam _ _) returnSM (mkLams bndrs' body'', filtered_uds) where (bndrs, body) = collectBinders e - (subst', bndrs') = substBndrs subst bndrs + (subst', bndrs') = simplBndrs subst bndrs -- More efficient to collect a group of binders together all at once -- and we don't want to split a lambda group with dumped bindings @@ -667,7 +663,7 @@ specExpr subst (Case scrut case_bndr alts) mapAndCombineSM spec_alt alts `thenSM` \ (alts', uds_alts) -> returnSM (Case scrut' case_bndr' alts', uds_scrut `plusUDs` uds_alts) where - (subst_alt, case_bndr') = substId subst case_bndr + (subst_alt, case_bndr') = simplBndr subst case_bndr -- No need to clone case binder; it can't float like a let(rec) spec_alt (con, args, rhs) @@ -677,7 +673,7 @@ specExpr subst (Case scrut case_bndr alts) in returnSM ((con, args', rhs''), uds') where - (subst_rhs, args') = substBndrs subst_alt args + (subst_rhs, args') = simplBndrs subst_alt args ---------------- Finally, let is the interesting case -------------------- specExpr subst (Let bind body) @@ -788,10 +784,15 @@ specDefn :: Subst -- Subst to use for RHS specDefn subst calls (fn, rhs) -- The first case is the interesting one - | n_tyvars == length rhs_tyvars -- Rhs of fn's defn has right number of big lambdas - && n_dicts <= length rhs_bndrs -- and enough dict args - && not (null calls_for_me) -- And there are some calls to specialise - && not (certainlyWillInline fn) -- And it's not small + | rhs_tyvars `lengthIs` n_tyvars -- Rhs of fn's defn has right number of big lambdas + && rhs_bndrs `lengthAtLeast` n_dicts -- and enough dict args + && notNull calls_for_me -- And there are some calls to specialise + +-- At one time I tried not specialising small functions +-- but sometimes there are big functions marked INLINE +-- that we'd like to specialise. In particular, dictionary +-- functions, which Marcin is keen to inline +-- && not (certainlyWillInline fn) -- And it's not small -- If it's small, it's better just to inline -- it than to construct lots of specialisations = -- Specialise the body of the function @@ -813,17 +814,21 @@ specDefn subst calls (fn, rhs) returnSM ((zapped_fn, rhs'), [], rhs_uds) where - zapped_fn = modifyIdInfo zapSpecPragInfo fn + zapped_fn = zapSpecPragmaId fn -- If the fn is a SpecPragmaId, make it discardable -- It's role as a holder for a call instance is o'er -- But it might be alive for some other reason by now. fn_type = idType fn - (tyvars, theta, _) = splitSigmaTy fn_type + (tyvars, theta, _) = tcSplitSigmaTy fn_type n_tyvars = length tyvars n_dicts = length theta - (rhs_tyvars, rhs_ids, rhs_body) = collectTyAndValBinders rhs + -- It's important that we "see past" any INLINE pragma + -- else we'll fail to specialise an INLINE thing + (inline_me, rhs') = dropInline rhs + (rhs_tyvars, rhs_ids, rhs_body) = collectTyAndValBinders rhs' + rhs_dicts = take n_dicts rhs_ids rhs_bndrs = rhs_tyvars ++ rhs_dicts body = mkLams (drop n_dicts rhs_ids) rhs_body @@ -835,12 +840,12 @@ specDefn subst calls (fn, rhs) ---------------------------------------------------------- -- Specialise to one particular call pattern - spec_call :: ([Maybe Type], ([DictExpr], VarSet)) -- Call instance + spec_call :: (CallKey, ([DictExpr], VarSet)) -- Call instance -> SpecM ((Id,CoreExpr), -- Specialised definition UsageDetails, -- Usage details from specialised body CoreRule) -- Info for the Id's SpecEnv - spec_call (call_ts, (call_ds, call_fvs)) - = ASSERT( length call_ts == n_tyvars && length call_ds == n_dicts ) + spec_call (CallKey call_ts, (call_ds, call_fvs)) + = ASSERT( call_ts `lengthIs` n_tyvars && call_ds `lengthIs` n_dicts ) -- Calls are only recorded for properly-saturated applications -- Suppose f's defn is f = /\ a b c d -> \ d1 d2 -> rhs @@ -880,22 +885,34 @@ specDefn subst calls (fn, rhs) let -- The rule to put in the function's specialisation is: -- forall b,d, d1',d2'. f t1 b t3 d d1' d2' = f1 b d - spec_env_rule = Rule (_PK_ ("SPEC " ++ showSDoc (ppr fn))) + spec_env_rule = Rule (mkFastString ("SPEC " ++ showSDoc (ppr fn))) + AlwaysActive (poly_tyvars ++ rhs_dicts') inst_args (mkTyApps (Var spec_f) (map mkTyVarTy poly_tyvars)) -- Add the { d1' = dx1; d2' = dx2 } usage stuff final_uds = foldr addDictBind rhs_uds (my_zipEqual "spec_call" rhs_dicts' call_ds) + + -- NOTE: we don't add back in any INLINE pragma on the RHS, so even if + -- the original function said INLINE, the specialised copies won't. + -- The idea is that the point of inlining was precisely to specialise + -- the function at its call site, and that's not so important for the + -- specialised copies. But it still smells like an ad hoc decision. + in - returnSM ((spec_f, spec_rhs), + returnSM ((spec_f, spec_rhs), final_uds, spec_env_rule) where my_zipEqual doc xs ys - | length xs /= length ys = pprPanic "my_zipEqual" (ppr xs $$ ppr ys $$ (ppr fn <+> ppr call_ts) $$ ppr rhs) - | otherwise = zipEqual doc xs ys + | not (equalLength xs ys) = pprPanic "my_zipEqual" (ppr xs $$ ppr ys $$ (ppr fn <+> ppr call_ts) $$ ppr rhs) + | otherwise = zipEqual doc xs ys + +dropInline :: CoreExpr -> (Bool, CoreExpr) +dropInline (Note InlineMe rhs) = (True, rhs) +dropInline rhs = (False, rhs) \end{code} %************************************************************************ @@ -925,12 +942,13 @@ type DictExpr = CoreExpr emptyUDs = MkUD { dict_binds = emptyBag, calls = emptyFM } type ProtoUsageDetails = ([DictBind], - [(Id, [Maybe Type], ([DictExpr], VarSet))] + [(Id, CallKey, ([DictExpr], VarSet))] ) ------------------------------------------------------------ type CallDetails = FiniteMap Id CallInfo -type CallInfo = FiniteMap [Maybe Type] -- Nothing => unconstrained type argument +newtype CallKey = CallKey [Maybe Type] -- Nothing => unconstrained type argument +type CallInfo = FiniteMap CallKey ([DictExpr], VarSet) -- Dict args and the vars of the whole -- call (including tyvars) -- [*not* include the main id itself, of course] @@ -938,12 +956,25 @@ type CallInfo = FiniteMap [Maybe Type] -- Nothing => unconstrained type ar -- The list of types and dictionaries is guaranteed to -- match the type of f +-- Type isn't an instance of Ord, so that we can control which +-- instance we use. That's tiresome here. Oh well +instance Eq CallKey where + k1 == k2 = case k1 `compare` k2 of { EQ -> True; other -> False } + +instance Ord CallKey where + compare (CallKey k1) (CallKey k2) = cmpList cmp k1 k2 + where + cmp Nothing Nothing = EQ + cmp Nothing (Just t2) = LT + cmp (Just t1) Nothing = GT + cmp (Just t1) (Just t2) = tcCmpType t1 t2 + unionCalls :: CallDetails -> CallDetails -> CallDetails unionCalls c1 c2 = plusFM_C plusFM c1 c2 singleCall :: Id -> [Maybe Type] -> [DictExpr] -> CallDetails singleCall id tys dicts - = unitFM id (unitFM tys (dicts, call_fvs)) + = unitFM id (unitFM (CallKey tys) (dicts, call_fvs)) where call_fvs = exprsFreeVars dicts `unionVarSet` tys_fvs tys_fvs = tyVarsOfTypes (catMaybes tys) @@ -965,14 +996,18 @@ listToCallDetails calls callDetailsToList calls = [ (id,tys,dicts) | (id,fm) <- fmToList calls, - (tys,dicts) <- fmToList fm + (tys, dicts) <- fmToList fm ] mkCallUDs subst f args | null theta - || length spec_tys /= n_tyvars - || length dicts /= n_dicts - || maybeToBool (lookupRule (substInScope subst) f args) + || not (all isClassPred theta) + -- Only specialise if all overloading is on class params. + -- In ptic, with implicit params, the type args + -- *don't* say what the value of the implicit param is! + || not (spec_tys `lengthIs` n_tyvars) + || not ( dicts `lengthIs` n_dicts) + || maybeToBool (lookupRule (\act -> True) (substInScope subst) f args) -- There's already a rule covering this call. A typical case -- is where there's an explicit user-provided rule. Then -- we don't want to create a specialised version @@ -984,7 +1019,7 @@ mkCallUDs subst f args calls = singleCall f spec_tys dicts } where - (tyvars, theta, _) = splitSigmaTy (idType f) + (tyvars, theta, _) = tcSplitSigmaTy (idType f) constrained_tyvars = tyVarsOfTheta theta n_tyvars = length tyvars n_dicts = length theta @@ -992,10 +1027,9 @@ mkCallUDs subst f args spec_tys = [mk_spec_ty tv ty | (tv, Type ty) <- tyvars `zip` args] dicts = [dict_expr | (_, dict_expr) <- theta `zip` (drop n_tyvars args)] - mk_spec_ty tyvar ty | tyvar `elemVarSet` constrained_tyvars - = Just ty - | otherwise - = Nothing + mk_spec_ty tyvar ty + | tyvar `elemVarSet` constrained_tyvars = Just ty + | otherwise = Nothing ------------------------------------------------------------ plusUDs :: UsageDetails -> UsageDetails -> UsageDetails @@ -1085,12 +1119,6 @@ splitUDs bndrs uds@(MkUD {dict_binds = orig_dbs, %************************************************************************ \begin{code} -lookupId:: IdEnv Id -> Id -> Id -lookupId env id = case lookupVarEnv env id of - Nothing -> id - Just id' -> id' - ----------------------------------------- type SpecM a = UniqSM a thenSM = thenUs @@ -1108,25 +1136,22 @@ cloneBindSM :: Subst -> CoreBind -> SpecM (Subst, Subst, CoreBind) -- Clone the binders of the bind; return new bind with the cloned binders -- Return the substitution to use for RHSs, and the one to use for the body cloneBindSM subst (NonRec bndr rhs) - = withUs $ \ us -> + = getUs `thenUs` \ us -> let - (subst', us', bndr') = substAndCloneId subst us bndr + (subst', bndr') = substAndCloneId subst us bndr in - ((subst, subst', NonRec bndr' rhs), us') + returnUs (subst, subst', NonRec bndr' rhs) cloneBindSM subst (Rec pairs) - = withUs $ \ us -> + = getUs `thenUs` \ us -> let - (subst', us', bndrs') = substAndCloneIds subst us (map fst pairs) + (subst', bndrs') = substAndCloneRecIds subst us (map fst pairs) in - ((subst', subst', Rec (bndrs' `zip` map snd pairs)), us') + returnUs (subst', subst', Rec (bndrs' `zip` map snd pairs)) cloneBinders subst bndrs - = withUs $ \ us -> - let - (subst', us', bndrs') = substAndCloneIds subst us bndrs - in - ((subst', bndrs'), us') + = getUs `thenUs` \ us -> + returnUs (substAndCloneIds subst us bndrs) newIdSM old_id new_ty = getUniqSM `thenSM` \ uniq ->