X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FDsBinds.lhs;h=dc934a77a7104e54bd3d0883cb62c8b2c98204e6;hb=6eb5c1509c2fd796c135ae18b650ddd658c48624;hp=f03877360eda53a48e1cbce0dc3ce416a30c0fc9;hpb=c1a1488fab7e40bdb269fcd6bfa1e547a8a562a1;p=ghc-hetmet.git diff --git a/compiler/deSugar/DsBinds.lhs b/compiler/deSugar/DsBinds.lhs index f038773..dc934a7 100644 --- a/compiler/deSugar/DsBinds.lhs +++ b/compiler/deSugar/DsBinds.lhs @@ -10,13 +10,6 @@ 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(..) @@ -34,6 +27,7 @@ import DsUtils import HsSyn -- lots of things import CoreSyn -- lots of things import CoreUtils +import CoreFVs import TcHsSyn ( mkArbitraryType ) -- Mis-placed? import TcType @@ -42,6 +36,7 @@ import CostCentre import Module import Id import Var ( TyVar ) +import VarSet import Rules import VarEnv import Type @@ -88,25 +83,25 @@ dsHsBind :: AutoScc -> HsBind Id -> DsM [(Id,CoreExpr)] -- Result -dsHsBind auto_scc rest (VarBind var expr) - = dsLExpr expr `thenDs` \ core_expr -> +dsHsBind _ 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, fun_infix = inf }) - = matchWrapper (FunRhs (idName fun) inf) matches `thenDs` \ (args, body) -> - mkOptTickBox tick body `thenDs` \ body' -> - dsCoercion co_fn (return (mkLams args body')) `thenDs` \ rhs -> - returnDs ((fun,rhs) : 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 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 _ 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 @@ -146,23 +141,22 @@ dsHsBind auto_scc rest (AbsBinds [] [] exports binds) -- Another common case: one exported variable -- 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 -> + (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 + + 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 @@ -175,7 +169,7 @@ 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 @@ -200,16 +194,16 @@ 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 = 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]) @@ -242,17 +236,17 @@ 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 -dsSpec all_tvs dicts tvs poly_id mono_id mono_bind (L _ (InlinePrag {})) +dsSpec _ _ _ _ _ _ (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 @@ -272,7 +266,7 @@ 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) -> do + Just (_, args) -> do { f_body <- fix_up (Let mono_bind (Var mono_id)) @@ -283,9 +277,12 @@ dsSpec all_tvs dicts tvs poly_id mono_id mono_bind spec_rhs = Let (NonRec local_poly poly_f_body) ds_spec_expr 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)) } } } @@ -298,15 +295,16 @@ dsSpec all_tvs dicts tvs poly_id mono_id mono_bind void_tvs = all_tvs \\ tvs - dead_msg bs = vcat [ sep [ptext SLIT("Useless constraint") <> plural bs - <+> ptext SLIT("in specialied type:"), + dead_msg bs = vcat [ sep [ptext (sLit "Useless constraint") <> plural bs + <+> ptext (sLit "in specialied type:"), nest 2 (pprTheta (map get_pred bs))] - , ptext SLIT("SPECIALISE pragma ignored")] + , ptext (sLit "SPECIALISE pragma ignored")] get_pred b = ASSERT( isId b ) expectJust "dsSpec" (tcSplitPredTy_maybe (idType b)) - decomp_msg = hang (ptext SLIT("Specialisation too complicated to desugar; ignored")) + decomp_msg = hang (ptext (sLit "Specialisation too complicated to desugar; ignored")) 2 (ppr spec_expr) +dsMkArbitraryType :: TcTyVar -> DsM Type dsMkArbitraryType tv = mkArbitraryType warn tv where warn span msg = putSrcSpanDs span (warnDs msg) @@ -329,17 +327,23 @@ 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 + %************************************************************************ @@ -355,16 +359,16 @@ decomposeRuleLhs lhs = go emptyVarEnv (occurAnalyseExpr lhs) -- Occurrence analysis sorts out the dict -- bindings so we know if they are recursive where - -- 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 + -- 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 (extendVarEnv env dict (simpleSubst env rhs)) body go env body - = case collectArgs (simpleSubst env body) of - (Var fn, args) -> Just (fn, args) - other -> Nothing + = case collectArgs (simpleSubst env body) of + (Var fn, args) -> Just (fn, args) + _ -> Nothing simpleSubst :: IdEnv CoreExpr -> CoreExpr -> CoreExpr -- Similar to CoreSubst.substExpr, except that @@ -435,17 +439,18 @@ If profiling and dealing with a dict binding, wrap the dict in @_scc_ DICT @: \begin{code} -addDictScc var rhs = returnDs rhs +addDictScc :: Id -> CoreExpr -> DsM CoreExpr +addDictScc _ 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} @@ -461,7 +466,7 @@ addDictScc var rhs = returnDs rhs dsCoercion :: HsWrapper -> DsM CoreExpr -> DsM CoreExpr dsCoercion WpHole thing_inside = thing_inside dsCoercion (WpCompose c1 c2) thing_inside = dsCoercion c1 (dsCoercion c2 thing_inside) -dsCoercion (WpCo co) thing_inside = do { expr <- thing_inside +dsCoercion (WpCast co) thing_inside = do { expr <- thing_inside ; return (Cast expr co) } dsCoercion (WpLam id) thing_inside = do { expr <- thing_inside ; return (Lam id expr) }