X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FDsBinds.lhs;h=691ac841a295c8db495d11509041387b4850acf8;hb=6c7b41cc2b24f533697a62bf1843507ae043fc97;hp=4d2f9f15dde66cf24a867421dcfbb977ce6998ce;hpb=e5ca7e6e5137a2e6081717e5e90ca52a30840f68;p=ghc-hetmet.git diff --git a/compiler/deSugar/DsBinds.lhs b/compiler/deSugar/DsBinds.lhs index 4d2f9f1..691ac84 100644 --- a/compiler/deSugar/DsBinds.lhs +++ b/compiler/deSugar/DsBinds.lhs @@ -10,6 +10,13 @@ in that the @Rec@/@NonRec@/etc structure is thrown away (whereas at lower levels it is preserved with @let@/@letrec@s). \begin{code} +{-# OPTIONS -w #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module DsBinds ( dsTopLHsBinds, dsLHsBinds, decomposeRuleLhs, dsCoercion, AutoScc(..) @@ -27,6 +34,7 @@ import DsUtils import HsSyn -- lots of things import CoreSyn -- lots of things import CoreUtils +import CoreFVs import TcHsSyn ( mkArbitraryType ) -- Mis-placed? import TcType @@ -35,6 +43,7 @@ import CostCentre import Module import Id import Var ( TyVar ) +import VarSet import Rules import VarEnv import Type @@ -46,7 +55,6 @@ import BasicTypes hiding ( TopLevel ) import FastString import Util ( mapSnd ) - import Control.Monad import Data.List \end{code} @@ -82,24 +90,25 @@ dsHsBind :: AutoScc -> HsBind Id -> DsM [(Id,CoreExpr)] -- Result -dsHsBind auto_scc rest (VarBind var expr) - = dsLExpr expr `thenDs` \ core_expr -> +dsHsBind auto_scc rest (VarBind var expr) = do + core_expr <- dsLExpr expr - -- Dictionary bindings are always VarMonoBinds, so - -- we only need do this here - addDictScc var core_expr `thenDs` \ core_expr' -> - returnDs ((var, core_expr') : rest) + -- Dictionary bindings are always VarMonoBinds, so + -- we only need do this here + core_expr' <- addDictScc var core_expr + return ((var, core_expr') : rest) -dsHsBind auto_scc rest (FunBind { fun_id = L _ fun, fun_matches = matches, fun_co_fn = co_fn, fun_tick = tick }) - = matchWrapper (FunRhs (idName fun)) matches `thenDs` \ (args, body) -> - mkOptTickBox tick body `thenDs` \ body' -> - dsCoercion co_fn (return (mkLams args body')) `thenDs` \ rhs -> - returnDs ((fun,rhs) : rest) +dsHsBind auto_scc 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 auto_scc rest (PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty }) - = dsGuarded grhss ty `thenDs` \ body_expr -> - mkSelectorBinds pat body_expr `thenDs` \ sel_binds -> - returnDs (sel_binds ++ rest) +dsHsBind auto_scc 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] -- Common special case: no type or dictionary abstraction @@ -140,22 +149,21 @@ dsHsBind auto_scc rest (AbsBinds [] [] exports binds) -- Non-recursive bindings come through this way dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports@[(tyvars, global, local, prags)] binds) - = ASSERT( all (`elem` tyvars) all_tyvars ) - ds_lhs_binds NoSccs binds `thenDs` \ core_prs -> - let - -- Always treat the binds as recursive, because the typechecker - -- makes rather mixed-up dictionary bindings - core_bind = Rec core_prs - in - mappM (dsSpec all_tyvars dicts tyvars global local core_bind) - prags `thenDs` \ mb_specs -> + = 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 + + 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' - in - returnDs (bind : spec_binds ++ rest) + (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' + + return (bind : spec_binds ++ rest) dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) = do { core_prs <- ds_lhs_binds NoSccs binds @@ -168,7 +176,7 @@ dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) -- Rec because of mixed-up dictionary bindings core_bind = Rec (map do_one core_prs) - tup_expr = mkTupleExpr locals + tup_expr = mkBigCoreVarTup locals tup_ty = exprType tup_expr poly_tup_expr = mkLams all_tyvars $ mkLams dicts $ Let core_bind tup_expr @@ -182,7 +190,9 @@ dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) mk_bind ((tyvars, global, local, prags), n) -- locals !! n == local = -- Need to make fresh locals to bind in the selector, because -- some of the tyvars will be bound to 'Any' - do { locals' <- newSysLocalsDs (map substitute local_tys) + do { ty_args <- mapM mk_ty_arg all_tyvars + ; 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) prags @@ -191,17 +201,16 @@ dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) rhs = mkLams tyvars $ mkLams dicts $ mkTupleSelector locals' (locals' !! n) tup_id $ mkApps (mkTyApps (Var poly_tup_id) ty_args) dict_args - ; returnDs ((global', rhs) : spec_binds) } + ; return ((global', rhs) : spec_binds) } where - mk_ty_arg all_tyvar | all_tyvar `elem` tyvars = mkTyVarTy all_tyvar - | otherwise = mkArbitraryType all_tyvar - ty_args = map mk_ty_arg all_tyvars - substitute = substTyWith all_tyvars ty_args + mk_ty_arg all_tyvar + | all_tyvar `elem` tyvars = return (mkTyVarTy all_tyvar) + | otherwise = dsMkArbitraryType all_tyvar - ; export_binds_s <- mappM mk_bind (exports `zip` [0..]) + ; export_binds_s <- mapM mk_bind (exports `zip` [0..]) -- don't scc (auto-)annotate the tuple itself. - ; returnDs ((poly_tup_id, poly_tup_expr) : + ; return ((poly_tup_id, poly_tup_expr) : (concat export_binds_s ++ rest)) } mkABEnv :: [([TyVar], Id, Id, [LPrag])] -> VarEnv (Id, [LPrag]) @@ -234,8 +243,9 @@ dsSpec :: [TyVar] -> [DictId] -> [TyVar] -- inlined and specialised -- -- Given SpecPrag (/\as.\ds. f es) t, we have --- the defn f_spec as ds = f es --- and the RULE f es = f_spec as ds +-- the defn f_spec as ds = let-nonrec f = /\fas\fds. let f_mono = in f_mono +-- in f es +-- and the RULE forall as, ds. f es = f_spec as ds -- -- It is *possible* that 'es' does not mention all of the dictionaries 'ds' -- (a bit silly, because then the @@ -243,8 +253,7 @@ dsSpec all_tvs dicts tvs poly_id mono_id mono_bind (L _ (InlinePrag {})) = return Nothing dsSpec all_tvs dicts tvs poly_id mono_id mono_bind - (L loc (SpecPrag spec_expr spec_ty _const_dicts inl)) - -- See Note [Const rule dicts] + (L loc (SpecPrag spec_expr spec_ty inl)) = putSrcSpanDs loc $ do { let poly_name = idName poly_id ; spec_name <- newLocalName poly_name @@ -264,27 +273,33 @@ dsSpec all_tvs dicts tvs poly_id mono_id mono_bind case mb_lhs of Nothing -> do { warnDs decomp_msg; return Nothing } - Just (var, args) -> return (Just (addInlineInfo inl spec_id spec_rhs, rule)) - where - local_poly = setIdNotExported poly_id + Just (var, args) -> do + + { 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_rhs = Let (NonRec local_poly poly_f_body) ds_spec_expr - poly_f_body = mkLams (tvs ++ dicts) $ - fix_up (Let mono_bind (Var mono_id)) + poly_f_body = mkLams (tvs ++ dicts) f_body + + extra_dict_bndrs = filter isDictId (varSetElems (exprFreeVars ds_spec_expr)) + -- Note [Const rule dicts] rule = mkLocalRule (mkFastString ("SPEC " ++ showSDoc (ppr poly_name))) AlwaysActive poly_name - bndrs args + (extra_dict_bndrs ++ bndrs) args (mkVarApps (Var spec_id) bndrs) - } } + ; return (Just (addInlineInfo inl spec_id spec_rhs, rule)) + } } } where -- Bind to Any any of all_ptvs that aren't -- relevant for this particular function - fix_up body | null void_tvs = body - | otherwise = mkTyApps (mkLams void_tvs body) - (map mkArbitraryType void_tvs) + fix_up body | null void_tvs = return body + | otherwise = do { void_tys <- mapM dsMkArbitraryType void_tvs + ; return (mkTyApps (mkLams void_tvs body) void_tys) } + void_tvs = all_tvs \\ tvs dead_msg bs = vcat [ sep [ptext SLIT("Useless constraint") <> plural bs @@ -295,6 +310,10 @@ 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) + +dsMkArbitraryType tv = mkArbitraryType warn tv + where + warn span msg = putSrcSpanDs span (warnDs msg) \end{code} Note [Unused spec binders] @@ -314,17 +333,23 @@ a mistake. That's what the isDeadBinder call detects. Note [Const rule dicts] ~~~~~~~~~~~~~~~~~~~~~~~ -A SpecPrag has a field for "constant dicts" in the RULE, but I think -it's pretty useless. See the place where it's generated in TcBinds. -TcSimplify will discharge a constraint by binding it to, say, -GHC.Base.$f2 :: Eq Int, withour putting anything in the LIE, so this -dict won't show up in the const-dicts field. It probably doesn't matter, -because the rule will end up being something like - f Int GHC.Base.$f2 = ... -rather than - forall d. f Int d = ... -The latter is more general, but in practice I think it won't make any -difference. +When the LHS of a specialisation rule, (/\as\ds. f es) has a free dict, +which is presumably in scope at the function definition site, we can quantify +over it too. *Any* dict with that type will do. + +So for example when you have + f :: Eq a => a -> a + f = + {-# SPECIALISE f :: Int -> Int #-} + +Then we get the SpecPrag + SpecPrag (f Int dInt) Int + +And from that we want the rule + + RULE forall dInt. f Int dInt = f_spec + f_spec = let f = in f Int dInt + %************************************************************************ @@ -420,17 +445,17 @@ If profiling and dealing with a dict binding, wrap the dict in @_scc_ DICT @: \begin{code} -addDictScc var rhs = returnDs rhs +addDictScc var rhs = return rhs {- DISABLED for now (need to somehow make up a name for the scc) -- SDM | not ( opt_SccProfilingOn && opt_AutoSccsOnDicts) || not (isDictId var) - = returnDs rhs -- That's easy: do nothing + = return rhs -- That's easy: do nothing | otherwise - = getModuleAndGroupDs `thenDs` \ (mod, grp) -> + = do (mod, grp) <- getModuleAndGroupDs -- ToDo: do -dicts-all flag (mark dict things with individual CCs) - returnDs (Note (SCC (mkAllDictsCC mod grp False)) rhs) + return (Note (SCC (mkAllDictsCC mod grp False)) rhs) -} \end{code} @@ -456,6 +481,8 @@ dsCoercion (WpApp id) thing_inside = do { expr <- thing_inside ; return (App expr (Var id)) } 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) }