X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FdeSugar%2FDsBinds.lhs;h=e9ab4e897c7eb186cde265224308eda0b83b5974;hp=3df57d77a14d5426153ca05506beb80b7659acc0;hb=d95ce839533391e7118257537044f01cbb1d6694;hpb=a1a96ab952241f1ffbe3e3246bc2fb1715bbcf3b diff --git a/compiler/deSugar/DsBinds.lhs b/compiler/deSugar/DsBinds.lhs index 3df57d7..e9ab4e8 100644 --- a/compiler/deSugar/DsBinds.lhs +++ b/compiler/deSugar/DsBinds.lhs @@ -23,21 +23,21 @@ import {-# SOURCE #-} Match( matchWrapper ) import DsMonad import DsGRHSs import DsUtils +import OccurAnal import HsSyn -- lots of things import CoreSyn -- lots of things import MkCore import CoreUtils +import CoreUnfold import CoreFVs import TcHsSyn ( mkArbitraryType ) -- Mis-placed? import TcType -import OccurAnal import CostCentre import Module import Id -import Name ( localiseName ) -import Var ( TyVar ) +import Var ( Var, TyVar ) import VarSet import Rules import VarEnv @@ -49,7 +49,7 @@ import Bag import BasicTypes hiding ( TopLevel ) import FastString import StaticFlags ( opt_DsMultiTyVar ) -import Util ( mapSnd, mapAndUnzip, lengthExceeds ) +import Util ( mapSnd, count, mapAndUnzip, lengthExceeds ) import Control.Monad import Data.List @@ -71,6 +71,7 @@ dsLHsBinds binds = ds_lhs_binds NoSccs binds ------------------------ ds_lhs_binds :: AutoScc -> LHsBinds Id -> DsM [(Id,CoreExpr)] + -- scc annotation policy (see below) ds_lhs_binds auto_scc binds = foldM (dsLHsBind auto_scc) [] (bagToList binds) @@ -86,25 +87,30 @@ dsHsBind :: AutoScc -> HsBind Id -> DsM [(Id,CoreExpr)] -- Result -dsHsBind _ rest (VarBind var expr) = do - core_expr <- dsLExpr expr +dsHsBind _ rest (VarBind var expr inline_regardless) + = do { core_expr <- dsLExpr expr - -- Dictionary bindings are always VarMonoBinds, so - -- we only need do this here - core_expr' <- addDictScc var core_expr - return ((var, core_expr') : rest) + -- Dictionary bindings are always VarBinds, + -- so we only need do this here + ; core_expr' <- addDictScc var core_expr + ; let var' | inline_regardless = var `setIdUnfolding` mkCompulsoryUnfolding core_expr' + | otherwise = var -dsHsBind _ rest (FunBind { fun_id = L _ fun, fun_matches = matches, - fun_co_fn = co_fn, fun_tick = tick, fun_infix = inf }) = do - (args, body) <- matchWrapper (FunRhs (idName fun) inf) matches - body' <- mkOptTickBox tick body - rhs <- dsCoercion co_fn (return (mkLams args body')) - return ((fun,rhs) : rest) + ; return ((var', core_expr') : rest) } -dsHsBind _ rest (PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty }) = do - body_expr <- dsGuarded grhss ty - sel_binds <- mkSelectorBinds pat body_expr - return (sel_binds ++ rest) +dsHsBind _ rest + (FunBind { fun_id = L _ fun, fun_matches = matches, + fun_co_fn = co_fn, fun_tick = tick, fun_infix = inf }) + = do { (args, body) <- matchWrapper (FunRhs (idName fun) inf) matches + ; body' <- mkOptTickBox tick body + ; rhs <- dsCoercion co_fn (return (mkLams args body')) + ; return ((fun,rhs) : rest) } + +dsHsBind _ rest + (PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty }) + = do { body_expr <- dsGuarded grhss ty + ; sel_binds <- mkSelectorBinds pat body_expr + ; return (sel_binds ++ rest) } {- Note [Rules and inlining] ~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -133,10 +139,14 @@ dsHsBind _ rest (PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty }) = dsHsBind auto_scc rest (AbsBinds [] [] exports binds) = do { core_prs <- ds_lhs_binds NoSccs binds ; let env = mkABEnv exports - do_one (lcl_id, rhs) | Just (_, gbl_id, _, prags) <- lookupVarEnv env lcl_id - = addInlinePrags prags gbl_id $ - addAutoScc auto_scc gbl_id rhs - | otherwise = (lcl_id, rhs) + ar_env = mkArityEnv binds + do_one (lcl_id, rhs) + | Just (_, gbl_id, _, prags) <- lookupVarEnv env lcl_id + = makeCorePair gbl_id (lookupArity ar_env lcl_id) prags $ + addAutoScc auto_scc gbl_id rhs + + | otherwise = (lcl_id, rhs) + locals' = [(lcl_id, Var gbl_id) | (_, gbl_id, lcl_id, _) <- exports] -- Note [Rules and inlining] ; return (map do_one core_prs ++ locals' ++ rest) } @@ -164,14 +174,16 @@ dsHsBind auto_scc rest (AbsBinds [] [] exports binds) where B is the *non-recursive* binding fl = fg a b gl = gg b - h = h a b + h = h a b -- See (b); note shadowing! Notice (a) g has a different number of type variables to f, so we must use the mkArbitraryType thing to fill in the gaps. We use a type-let to do that. (b) The local variable h isn't in the exports, and rather than - clone a fresh copy we simply replace h by (h a b). + clone a fresh copy we simply replace h by (h a b), where + the two h's have different types! Shadowing happens here, + which looks confusing but works fine. (c) The result is *still* quadratic-sized if there are a lot of small bindings. So if there are more than some small @@ -202,17 +214,18 @@ dsHsBind auto_scc rest (AbsBinds tyvars [] exports binds) where fvs = exprSomeFreeVars (`elemVarSet` bndrs) rhs + ar_env = mkArityEnv binds env = mkABEnv exports do_one (lcl_id, rhs) | Just (id_tvs, gbl_id, _, prags) <- lookupVarEnv env lcl_id - = (NonRec lcl_id (mkTyApps (Var gbl_id) (mkTyVarTys id_tvs)), - addInlinePrags prags gbl_id $ - addAutoScc auto_scc gbl_id $ - mkLams id_tvs $ - mkLets [ NonRec tv (Type (lookupVarEnv_NF arby_env tv)) - | tv <- tyvars, not (tv `elem` id_tvs)] $ - add_lets rhs) + = let rhs' = addAutoScc auto_scc gbl_id $ + mkLams id_tvs $ + mkLets [ NonRec tv (Type (lookupVarEnv_NF arby_env tv)) + | tv <- tyvars, not (tv `elem` id_tvs)] $ + add_lets rhs + in (NonRec lcl_id (mkTyApps (Var gbl_id) (mkTyVarTys id_tvs)), + makeCorePair gbl_id (lookupArity ar_env lcl_id) prags rhs') | otherwise = (NonRec lcl_id (mkTyApps (Var non_exp_gbl_id) (mkTyVarTys tyvars)), (non_exp_gbl_id, mkLams tyvars (add_lets rhs))) @@ -223,30 +236,35 @@ dsHsBind auto_scc rest (AbsBinds tyvars [] exports binds) -- Another common case: one exported variable -- Non-recursive bindings come through this way + -- So do self-recursive bindings, and recursive bindings + -- that have been chopped up with type signatures dsHsBind auto_scc rest (AbsBinds all_tyvars dicts [(tyvars, global, local, prags)] binds) - = ASSERT( all (`elem` tyvars) all_tyvars ) do - core_prs <- ds_lhs_binds NoSccs binds - let - -- Always treat the binds as recursive, because the typechecker - -- makes rather mixed-up dictionary bindings - core_bind = Rec core_prs + = ASSERT( all (`elem` tyvars) all_tyvars ) + do { core_prs <- ds_lhs_binds NoSccs binds + + ; let -- Always treat the binds as recursive, because the typechecker + -- makes rather mixed-up dictionary bindings + core_bind = Rec core_prs + inl_arity = lookupArity (mkArityEnv binds) local - mb_specs <- mapM (dsSpec all_tyvars dicts tyvars global local core_bind) prags - let - (spec_binds, rules) = unzip (catMaybes mb_specs) - global' = addIdSpecialisations global rules - rhs' = mkLams tyvars $ mkLams dicts $ Let core_bind (Var local) - bind = addInlinePrags prags global' $ addAutoScc auto_scc global' rhs' + ; mb_specs <- mapM (dsSpec all_tyvars dicts tyvars global + local inl_arity core_bind) prags + + ; let (spec_binds, rules) = unzip (catMaybes mb_specs) + global' = addIdSpecialisations global rules + rhs = addAutoScc auto_scc global $ + mkLams tyvars $ mkLams dicts $ Let core_bind (Var local) + main_bind = makeCorePair global' (inl_arity + length dicts) prags rhs - return (bind : spec_binds ++ rest) + ; return (main_bind : spec_binds ++ rest) } dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) = do { core_prs <- ds_lhs_binds NoSccs binds ; let env = mkABEnv exports - do_one (lcl_id,rhs) | Just (_, gbl_id, _, prags) <- lookupVarEnv env lcl_id - = addInlinePrags prags lcl_id $ - addAutoScc auto_scc gbl_id rhs + ar_env = mkArityEnv binds + do_one (lcl_id,rhs) | Just (_, gbl_id, _, _prags) <- lookupVarEnv env lcl_id + = (lcl_id, addAutoScc auto_scc gbl_id rhs) | otherwise = (lcl_id,rhs) -- Rec because of mixed-up dictionary bindings @@ -259,6 +277,12 @@ dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) locals = [local | (_, _, local, _) <- exports] local_tys = map idType locals + inl_prags :: [(Id, SrcSpan)] + inl_prags = [(id, loc) | (_, id, _, prags) <- exports + , L loc (InlinePrag {}) <- prags ] + + ; mapM_ discardedInlineWarning inl_prags + ; poly_tup_id <- newSysLocalDs (exprType poly_tup_expr) ; let dict_args = map Var dicts @@ -270,7 +294,8 @@ dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) ; let substitute = substTyWith all_tyvars ty_args ; locals' <- newSysLocalsDs (map substitute local_tys) ; tup_id <- newSysLocalDs (substitute tup_ty) - ; mb_specs <- mapM (dsSpec all_tyvars dicts tyvars global local core_bind) + ; mb_specs <- mapM (dsSpec all_tyvars dicts tyvars global local + (lookupArity ar_env local) core_bind) prags ; let (spec_binds, rules) = unzip (catMaybes mb_specs) global' = addIdSpecialisations global rules @@ -284,19 +309,60 @@ dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) | otherwise = dsMkArbitraryType all_tyvar ; export_binds_s <- mapM mk_bind (exports `zip` [0..]) - -- don't scc (auto-)annotate the tuple itself. + -- Don't scc (auto-)annotate the tuple itself. ; return ((poly_tup_id, poly_tup_expr) : (concat export_binds_s ++ rest)) } -mkABEnv :: [([TyVar], Id, Id, [LPrag])] -> VarEnv ([TyVar], Id, Id, [LPrag]) +------------------------ +makeCorePair :: Id-> Arity -> [LPrag] -> CoreExpr -> (Id, CoreExpr) +makeCorePair gbl_id arity prags rhs + = (addInline gbl_id arity rhs prags, rhs) + +------------------------ +discardedInlineWarning :: (Id, SrcSpan) -> DsM () +discardedInlineWarning (id, loc) + = putSrcSpanDs loc $ + warnDs $ sep [ ptext (sLit "Discarding INLINE pragma for") <+> ppr id + , ptext (sLit "because it is bound by a pattern, or a mutual recursion") ] + +------------------------ +type AbsBindEnv = VarEnv ([TyVar], Id, Id, [LPrag]) + -- Maps the "lcl_id" for an AbsBind to + -- its "gbl_id" and associated pragmas, if any + +mkABEnv :: [([TyVar], Id, Id, [LPrag])] -> AbsBindEnv -- Takes the exports of a AbsBinds, and returns a mapping -- lcl_id -> (tyvars, gbl_id, lcl_id, prags) mkABEnv exports = mkVarEnv [ (lcl_id, export) | export@(_, _, lcl_id, _) <- exports] +mkArityEnv :: LHsBinds Id -> IdEnv Arity + -- Maps a local to the arity of its definition +mkArityEnv binds = mkVarEnv (mapCatMaybes get_arity (bagToList binds)) + where + get_arity (L _ (FunBind { fun_id = id, fun_matches = ms })) = Just (unLoc id, matchGroupArity ms) + get_arity _ = Nothing + +lookupArity :: IdEnv Arity -> Id -> Arity +lookupArity ar_env id = lookupVarEnv ar_env id `orElse` 0 + +addInline :: Id -> Arity -> CoreExpr -> [LPrag] -> Id +addInline id arity rhs prags + = case [inl | L _ (InlinePrag inl) <- prags] of + [] -> id + (inl_spec : _) -> addInlineToId id arity rhs inl_spec + +addInlineToId :: Id -> Arity -> CoreExpr -> InlineSpec -> Id +addInlineToId id inl_arity rhs (Inline phase is_inline) + = id `setInlinePragma` phase + `setIdUnfolding` inline_rule + where + inline_rule | is_inline = mkInlineRule rhs inl_arity + | otherwise = noUnfolding +------------------------ dsSpec :: [TyVar] -> [DictId] -> [TyVar] - -> Id -> Id -- Global, local + -> Id -> Id -> Arity -- Global, local, arity of local -> CoreBind -> LPrag -> DsM (Maybe ((Id,CoreExpr), -- Binding for specialised Id CoreRule)) -- Rule for the Global Id @@ -324,45 +390,37 @@ dsSpec :: [TyVar] -> [DictId] -> [TyVar] -- -- It is *possible* that 'es' does not mention all of the dictionaries 'ds' -- (a bit silly, because then the -dsSpec _ _ _ _ _ _ (L _ (InlinePrag {})) +dsSpec _ _ _ _ _ _ _ (L _ (InlinePrag {})) = return Nothing -dsSpec all_tvs dicts tvs poly_id mono_id mono_bind +dsSpec all_tvs dicts tvs poly_id mono_id inl_arity mono_bind (L loc (SpecPrag spec_expr spec_ty inl)) = putSrcSpanDs loc $ do { let poly_name = idName poly_id ; spec_name <- newLocalName poly_name ; ds_spec_expr <- dsExpr spec_expr - ; let (bndrs, body) = collectBinders (occurAnalyseExpr ds_spec_expr) - -- ds_spec_expr may look like - -- /\a. f a Int dOrdInt - -- or /\a.\d:Ord a. let { dl::Ord [a] = dOrdList a d } in f [a] dl - -- The occurrence-analysis does two things - -- (a) identifies unused binders: Note [Unused spec binders] - -- (b) sorts dict bindings into NonRecs - -- so they can be inlined by decomposeRuleLhs - mb_lhs = decomposeRuleLhs body + ; case (decomposeRuleLhs ds_spec_expr) of { + Nothing -> do { warnDs decomp_msg; return Nothing } ; - -- Check for dead binders: Note [Unused spec binders] - ; case filter isDeadBinder bndrs of { - bs | not (null bs) -> do { warnDs (dead_msg bs); return Nothing } - | otherwise -> + Just (bndrs, _fn, args) -> - case mb_lhs of - Nothing -> do { warnDs decomp_msg; return Nothing } - - Just (_, args) -> do { + -- Check for dead binders: Note [Unused spec binders] + case filter isDeadBinder bndrs of { + bs | not (null bs) -> do { warnDs (dead_msg bs); return Nothing } + | otherwise -> do - f_body <- fix_up (Let mono_bind (Var mono_id)) + { f_body <- fix_up (Let mono_bind (Var mono_id)) ; let local_poly = setIdNotExported poly_id -- Very important to make the 'f' non-exported, -- else it won't be inlined! spec_id = mkLocalId spec_name spec_ty + spec_id1 = addInlineToId spec_id (inl_arity + count isDictId bndrs) + spec_rhs inl spec_rhs = Let (NonRec local_poly poly_f_body) ds_spec_expr poly_f_body = mkLams (tvs ++ dicts) f_body - extra_dict_bndrs = [localise d + extra_dict_bndrs = [localiseId d -- See Note [Constant rule dicts] | d <- varSetElems (exprFreeVars ds_spec_expr) , isDictId d] -- Note [Const rule dicts] @@ -371,8 +429,8 @@ dsSpec all_tvs dicts tvs poly_id mono_id mono_bind AlwaysActive poly_name (extra_dict_bndrs ++ bndrs) args (mkVarApps (Var spec_id) bndrs) - ; return (Just (addInlineInfo inl spec_id spec_rhs, rule)) - } } } + ; return (Just ((spec_id1, spec_rhs), rule)) + } } } } where -- Bind to Any any of all_ptvs that aren't -- relevant for this particular function @@ -390,9 +448,7 @@ dsSpec all_tvs dicts tvs poly_id mono_id mono_bind decomp_msg = hang (ptext (sLit "Specialisation too complicated to desugar; ignored")) 2 (ppr spec_expr) - - localise d = mkLocalId (localiseName (idName d)) (idType d) - -- See Note [Constant rule dicts] + mkArbitraryTypeEnv :: [TyVar] -> [([TyVar], a, b, c)] -> DsM (TyVarEnv Type) -- If any of the tyvars is missing from any of the lists in @@ -453,7 +509,7 @@ And from that we want the rule But be careful! That dInt might be GHC.Base.$fOrdInt, which is an External Name, and you can't bind them in a lambda or forall without getting things -confused. Hence the use of 'localise' to make it Internal. +confused. Hence the use of 'localiseId' to make it Internal. %************************************************************************ @@ -463,19 +519,31 @@ confused. Hence the use of 'localise' to make it Internal. %************************************************************************ \begin{code} -decomposeRuleLhs :: CoreExpr -> Maybe (Id, [CoreExpr]) +decomposeRuleLhs :: CoreExpr -> Maybe ([Var], Id, [CoreExpr]) +-- Take apart the LHS of a RULE. It's suuposed to look like +-- /\a. f a Int dOrdInt +-- or /\a.\d:Ord a. let { dl::Ord [a] = dOrdList a d } in f [a] dl +-- That is, the RULE binders are lambda-bound -- Returns Nothing if the LHS isn't of the expected shape decomposeRuleLhs lhs - = go emptyVarEnv (occurAnalyseExpr lhs) -- Occurrence analysis sorts out the dict - -- bindings so we know if they are recursive + = case (decomp emptyVarEnv body) of + Nothing -> Nothing + Just (fn, args) -> Just (bndrs, fn, args) where + occ_lhs = occurAnalyseExpr lhs + -- The occurrence-analysis does two things + -- (a) identifies unused binders: Note [Unused spec binders] + -- (b) sorts dict bindings into NonRecs + -- so they can be inlined by 'decomp' + (bndrs, body) = collectBinders occ_lhs + -- Substitute dicts in the LHS args, so that there -- aren't any lets getting in the way -- Note that we substitute the function too; we might have this as -- a LHS: let f71 = M.f Int in f71 - go env (Let (NonRec dict rhs) body) - = go (extendVarEnv env dict (simpleSubst env rhs)) body - go env body + decomp env (Let (NonRec dict rhs) body) + = decomp (extendVarEnv env dict (simpleSubst env rhs)) body + decomp env body = case collectArgs (simpleSubst env body) of (Var fn, args) -> Just (fn, args) _ -> Nothing @@ -507,23 +575,6 @@ simpleSubst subst expr go (Let (Rec pairs) body) = Let (Rec (mapSnd go pairs)) (go body) go (Case scrut bndr ty alts) = Case (go scrut) bndr ty [(c,bs,go r) | (c,bs,r) <- alts] - -addInlinePrags :: [LPrag] -> Id -> CoreExpr -> (Id,CoreExpr) -addInlinePrags prags bndr rhs - = case [inl | L _ (InlinePrag inl) <- prags] of - [] -> (bndr, rhs) - (inl:_) -> addInlineInfo inl bndr rhs - -addInlineInfo :: InlineSpec -> Id -> CoreExpr -> (Id,CoreExpr) -addInlineInfo (Inline phase is_inline) bndr rhs - = (attach_phase bndr phase, wrap_inline is_inline rhs) - where - attach_phase bndr phase - | isAlwaysActive phase = bndr -- Default phase - | otherwise = bndr `setInlinePragma` phase - - wrap_inline True body = mkInlineMe body - wrap_inline False body = body \end{code} @@ -587,12 +638,13 @@ dsCoercion (WpLam id) thing_inside = do { expr <- thing_inside ; return (Lam id expr) } dsCoercion (WpTyLam tv) thing_inside = do { expr <- thing_inside ; return (Lam tv expr) } -dsCoercion (WpApp id) thing_inside = do { expr <- thing_inside - ; return (App expr (Var id)) } +dsCoercion (WpApp v) thing_inside + | isTyVar v = do { expr <- thing_inside + {- Probably a coercion var -} ; return (App expr (Type (mkTyVarTy v))) } + | otherwise = do { expr <- thing_inside + {- An Id -} ; return (App expr (Var v)) } dsCoercion (WpTyApp ty) thing_inside = do { expr <- thing_inside ; return (App expr (Type ty)) } -dsCoercion WpInline thing_inside = do { expr <- thing_inside - ; return (mkInlineMe expr) } dsCoercion (WpLet bs) thing_inside = do { prs <- dsLHsBinds bs ; expr <- thing_inside ; return (Let (Rec prs) expr) }