X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsBinds.lhs;h=8f3006d0f338295e3057b45f0fb35c3e2802dbdd;hb=ac10f8408520a30e8437496d320b8b86afda2e8f;hp=6a1bc061061eddb6e525a4edd369319a9a65b6f2;hpb=dcef38bab91d45b56f7cf3ceeec96303d93728bb;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsBinds.lhs b/ghc/compiler/deSugar/DsBinds.lhs index 6a1bc06..8f3006d 100644 --- a/ghc/compiler/deSugar/DsBinds.lhs +++ b/ghc/compiler/deSugar/DsBinds.lhs @@ -1,5 +1,5 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[DsBinds]{Pattern-matching bindings (HsBinds and MonoBinds)} @@ -8,66 +8,46 @@ in that the @Rec@/@NonRec@/etc structure is thrown away (whereas at lower levels it is preserved with @let@/@letrec@s). \begin{code} +module DsBinds ( dsTopLHsBinds, dsLHsBinds, decomposeRuleLhs, + dsCoercion, + AutoScc(..) + ) where + #include "HsVersions.h" -module DsBinds ( dsBinds, dsMonoBinds ) where -IMP_Ubiq() -IMPORT_DELOOPER(DsLoop) -- break dsExpr-ish loop +import {-# SOURCE #-} DsExpr( dsLExpr, dsExpr ) +import {-# SOURCE #-} Match( matchWrapper ) -import HsSyn -- lots of things -import CoreSyn -- lots of things -import CoreUtils ( coreExprType ) -import TcHsSyn ( SYN_IE(TypecheckedHsBinds), SYN_IE(TypecheckedHsExpr), - SYN_IE(TypecheckedMonoBinds), - SYN_IE(TypecheckedPat) - ) import DsMonad import DsGRHSs ( dsGuarded ) import DsUtils -import Match ( matchWrapper ) - -import CmdLineOpts ( opt_SccProfilingOn, opt_AutoSccsOnAllToplevs, - opt_AutoSccsOnExportedToplevs, opt_CompilingGhcInternals ) -import CostCentre ( mkAutoCC, IsCafCC(..), mkAllDictsCC, preludeDictsCostCentre ) -import Id ( idType, SYN_IE(DictVar), GenId, SYN_IE(Id) ) -import ListSetOps ( minusList, intersectLists ) -import Name ( isExported ) -import PprType ( GenType ) -import PprStyle ( PprStyle(..) ) -import Type ( mkTyVarTy, isDictTy, instantiateTy - ) -import TyVar ( tyVarSetToList, GenTyVar{-instance Eq-} ) -import TysPrim ( voidTy ) -import Util ( isIn, panic{-, pprTrace ToDo:rm-} ) -\end{code} - -%************************************************************************ -%* * -\subsection[toplevel-and-regular-DsBinds]{Regular and top-level @dsBinds@} -%* * -%************************************************************************ -Like @dsBinds@, @dsBind@ returns a @[CoreBinding]@, but it may be -that some of the binders are of unboxed type. This is sorted out when -the caller wraps the bindings round an expression. - -\begin{code} -dsBinds :: TypecheckedHsBinds -> DsM [CoreBinding] - -dsBinds EmptyBinds = returnDs [] -dsBinds (ThenBinds binds_1 binds_2) = andDs (++) (dsBinds binds_1) (dsBinds binds_2) - -dsBinds (MonoBind binds sigs is_rec) - = dsMonoBinds is_rec binds `thenDs` \ prs -> - returnDs (if is_rec then - [Rec prs] - else - [NonRec binder rhs | (binder,rhs) <- prs] - ) +import HsSyn -- lots of things +import CoreSyn -- lots of things +import CoreUtils ( exprType, mkInlineMe, mkSCC ) + +import StaticFlags ( opt_AutoSccsOnAllToplevs, + opt_AutoSccsOnExportedToplevs ) +import OccurAnal ( occurAnalyseExpr ) +import CostCentre ( mkAutoCC, IsCafCC(..) ) +import Id ( Id, DictId, idType, idName, isExportedId, mkLocalId, setInlinePragma ) +import Rules ( addIdSpecialisations, mkLocalRule ) +import Var ( TyVar, Var, isGlobalId, setIdNotExported ) +import VarEnv +import Type ( mkTyVarTy, substTyWith ) +import TysWiredIn ( voidTy ) +import Outputable +import SrcLoc ( Located(..) ) +import Maybes ( isJust, catMaybes, orElse ) +import Bag ( bagToList ) +import BasicTypes ( Activation(..), InlineSpec(..), isAlwaysActive, defaultInlineSpec ) +import Monad ( foldM ) +import FastString ( mkFastString ) +import List ( (\\) ) +import Util ( mapSnd ) \end{code} - %************************************************************************ %* * \subsection[dsMonoBinds]{Desugaring a @MonoBinds@} @@ -75,91 +55,363 @@ dsBinds (MonoBind binds sigs is_rec) %************************************************************************ \begin{code} -dsMonoBinds :: RecFlag -> TypecheckedMonoBinds -> DsM [(Id,CoreExpr)] +dsTopLHsBinds :: AutoScc -> LHsBinds Id -> DsM [(Id,CoreExpr)] +dsTopLHsBinds auto_scc binds = ds_lhs_binds auto_scc binds + +dsLHsBinds :: LHsBinds Id -> DsM [(Id,CoreExpr)] +dsLHsBinds binds = ds_lhs_binds NoSccs binds -dsMonoBinds is_rec EmptyMonoBinds = returnDs [] -dsMonoBinds is_rec (AndMonoBinds binds_1 binds_2) - = andDs (++) (dsMonoBinds is_rec binds_1) (dsMonoBinds is_rec binds_2) +------------------------ +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) -dsMonoBinds is_rec (CoreMonoBind var core_expr) - = returnDs [(var, core_expr)] +dsLHsBind :: AutoScc + -> [(Id,CoreExpr)] -- Put this on the end (avoid quadratic append) + -> LHsBind Id + -> DsM [(Id,CoreExpr)] -- Result +dsLHsBind auto_scc rest (L loc bind) + = putSrcSpanDs loc $ dsHsBind auto_scc rest bind -dsMonoBinds is_rec (VarMonoBind var expr) - = dsExpr expr `thenDs` \ core_expr -> +dsHsBind :: AutoScc + -> [(Id,CoreExpr)] -- Put this on the end (avoid quadratic append) + -> HsBind Id + -> DsM [(Id,CoreExpr)] -- Result + +dsHsBind auto_scc rest (VarBind var expr) + = dsLExpr expr `thenDs` \ core_expr -> -- Dictionary bindings are always VarMonoBinds, so -- we only need do this here addDictScc var core_expr `thenDs` \ core_expr' -> - - returnDs [(var, core_expr')] - -dsMonoBinds is_rec (FunMonoBind fun _ matches locn) - = putSrcLocDs locn $ - matchWrapper (FunMatch fun) matches error_string `thenDs` \ (args, body) -> - returnDs [(fun, mkValLam args body)] - where - error_string = "function " ++ showForErr fun - -dsMonoBinds is_rec (PatMonoBind pat grhss_and_binds locn) - = putSrcLocDs locn $ - dsGuarded grhss_and_binds `thenDs` \ body_expr -> - mkSelectorBinds pat body_expr - -dsMonoBinds is_rec (AbsBinds [] [] exports binds) -- Common special case - = dsMonoBinds is_rec binds `thenDs` \ prs -> - returnDs (prs ++ [(global, Var local) | (_, global, local) <- exports]) - -dsMonoBinds is_rec (AbsBinds all_tyvars dicts exports binds) - = dsMonoBinds is_rec binds `thenDs` \ core_prs -> + returnDs ((var, core_expr') : rest) + +dsHsBind auto_scc rest (FunBind { fun_id = L _ fun, fun_matches = matches, fun_co_fn = co_fn }) + = matchWrapper (FunRhs (idName fun)) matches `thenDs` \ (args, body) -> + dsCoercion co_fn (return (mkLams args body)) `thenDs` \ rhs -> + addAutoScc auto_scc (fun, rhs) `thenDs` \ pair -> + returnDs (pair : 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 -> + mappM (addAutoScc auto_scc) sel_binds `thenDs` \ sel_binds -> + returnDs (sel_binds ++ rest) + + -- Common special case: no type or dictionary abstraction + -- For the (rare) case when there are some mixed-up + -- dictionary bindings (for which a Rec is convenient) + -- we reply on the enclosing dsBind to wrap a Rec around. +dsHsBind auto_scc rest (AbsBinds [] [] exports binds) + = ds_lhs_binds (addSccs auto_scc exports) binds `thenDs` \ core_prs -> + let + core_prs' = addLocalInlines exports core_prs + exports' = [(global, Var local) | (_, global, local, _) <- exports] + in + returnDs (core_prs' ++ exports' ++ rest) + + -- 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 (addSccs auto_scc exports) binds `thenDs` \ core_prs -> let - core_binds | is_rec = [Rec core_prs] - | otherwise = [NonRec b e | (b,e) <- core_prs] - - tup_expr = mkLam all_tyvars dicts $ - mkCoLetsAny core_binds $ - mkTupleExpr locals - locals = [local | (_, _, local) <- exports] - local_tys = map idType locals + -- 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 -> + let + (spec_binds, rules) = unzip (catMaybes mb_specs) + global' = addIdSpecialisations global rules + rhs' = mkLams tyvars $ mkLams dicts $ Let core_bind (Var local) + inl = case [inl | InlinePrag inl <- prags] of + [] -> defaultInlineSpec + (inl:_) -> inl + in + returnDs (addInlineInfo inl global' rhs' : spec_binds ++ rest) + +dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds) + = ds_lhs_binds (addSccs auto_scc exports) binds `thenDs` \ core_prs -> + let + -- Rec because of mixed-up dictionary bindings + core_bind = Rec (addLocalInlines exports core_prs) + + tup_expr = mkTupleExpr locals + tup_ty = exprType tup_expr + poly_tup_expr = mkLams all_tyvars $ mkLams dicts $ + Let core_bind tup_expr + locals = [local | (_, _, local, _) <- exports] + local_tys = map idType locals in - newSysLocalDs (coreExprType tup_expr) `thenDs` \ tup_id -> + newSysLocalDs (exprType poly_tup_expr) `thenDs` \ poly_tup_id -> let - dict_args = map VarArg dicts + dict_args = map Var dicts - mk_bind (tyvars, global, local) n -- locals !! n == local + 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 voidTy - newSysLocalsDs (map (instantiateTy env) local_tys) `thenDs` \ locals' -> - returnDs (global, mkLam tyvars dicts $ - mkTupleSelector locals' (locals' !! n) $ - mkValApp (mkTyApp (Var tup_id) ty_args) dict_args) + newSysLocalsDs (map substitute local_tys) `thenDs` \ locals' -> + newSysLocalDs (substitute tup_ty) `thenDs` \ tup_id -> + mapM (dsSpec all_tyvars dicts tyvars global local core_bind) + prags `thenDs` \ mb_specs -> + let + (spec_binds, rules) = unzip (catMaybes mb_specs) + global' = addIdSpecialisations global rules + rhs = mkLams tyvars $ mkLams dicts $ + mkTupleSelector locals' (locals' !! n) tup_id $ + mkApps (mkTyApps (Var poly_tup_id) ty_args) dict_args + in + returnDs ((global', rhs) : spec_binds) where mk_ty_arg all_tyvar | all_tyvar `elem` tyvars = mkTyVarTy all_tyvar | otherwise = voidTy - ty_args = map mk_ty_arg all_tyvars - env = all_tyvars `zip` ty_args + ty_args = map mk_ty_arg all_tyvars + substitute = substTyWith all_tyvars ty_args in - zipWithDs mk_bind exports [0..] `thenDs` \ export_binds -> - returnDs ((tup_id, tup_expr) : export_binds) + mappM mk_bind (exports `zip` [0..]) `thenDs` \ export_binds_s -> + -- don't scc (auto-)annotate the tuple itself. + + returnDs ((poly_tup_id, poly_tup_expr) : (concat export_binds_s ++ rest)) + +dsSpec :: [TyVar] -> [DictId] -> [TyVar] + -> Id -> Id -- Global, local + -> CoreBind -> Prag + -> DsM (Maybe ((Id,CoreExpr), -- Binding for specialised Id + CoreRule)) -- Rule for the Global Id + +-- Example: +-- f :: (Eq a, Ix b) => a -> b -> b +-- {-# SPECIALISE f :: Ix b => Int -> b -> b #-} +-- +-- AbsBinds [ab] [d1,d2] [([ab], f, f_mono, prags)] binds +-- +-- SpecPrag (/\b.\(d:Ix b). f Int b dInt d) +-- (forall b. Ix b => Int -> b -> b) +-- +-- Rule: forall b,(d:Ix b). f Int b dInt d = f_spec b d +-- +-- Spec bind: f_spec = Let f = /\ab \(d1:Eq a)(d2:Ix b). let binds in f_mono +-- /\b.\(d:Ix b). in f Int b dInt d +-- The idea is that f occurs just once, so it'll be +-- inlined and specialised + +dsSpec all_tvs dicts tvs poly_id mono_id mono_bind (InlinePrag {}) + = return Nothing + +dsSpec all_tvs dicts tvs poly_id mono_id mono_bind + (SpecPrag spec_expr spec_ty const_dicts inl) + = do { let poly_name = idName poly_id + ; spec_name <- newLocalName poly_name + ; ds_spec_expr <- dsExpr spec_expr + ; let (bndrs, body) = collectBinders ds_spec_expr + mb_lhs = decomposeRuleLhs (bndrs ++ const_dicts) body + + ; case mb_lhs of + Nothing -> do { dsWarn msg; return Nothing } + + Just (bndrs', var, args) -> return (Just (addInlineInfo inl spec_id spec_rhs, rule)) + where + 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)) + + -- Quantify over constant dicts on the LHS, since + -- their value depends only on their type + -- The ones we are interested in may even be imported + -- e.g. GHC.Base.dEqInt + + rule = mkLocalRule (mkFastString ("SPEC " ++ showSDoc (ppr poly_name))) + AlwaysActive poly_name + bndrs' -- Includes constant dicts + args + (mkVarApps (Var spec_id) bndrs) + } + where + -- Bind to voidTy 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 (const voidTy) void_tvs) + void_tvs = all_tvs \\ tvs + + msg = hang (ptext SLIT("Specialisation too complicated to desugar; ignored")) + 2 (ppr spec_expr) +\end{code} + + +%************************************************************************ +%* * +\subsection{Adding inline pragmas} +%* * +%************************************************************************ + +\begin{code} +decomposeRuleLhs :: [Var] -> CoreExpr -> Maybe ([Var], Id, [CoreExpr]) +-- Returns Nothing if the LHS isn't of the expected shape +-- The argument 'all_bndrs' includes the "constant dicts" of the LHS, +-- and they may be GlobalIds, which we can't forall-ify. +-- So we substitute them out instead +decomposeRuleLhs all_bndrs lhs + = go init_env (occurAnalyseExpr lhs) -- Occurrence analysis sorts out the dict + -- bindings so we know if they are recursive + where + + -- all_bndrs may include top-level imported dicts, + -- imported things with a for-all. + -- So we localise them and subtitute them out + bndr_prs = [ (id, Var (localise id)) | id <- all_bndrs, isGlobalId id ] + localise d = mkLocalId (idName d) (idType d) + + init_env = mkVarEnv bndr_prs + all_bndrs' = map subst_bndr all_bndrs + subst_bndr bndr = case lookupVarEnv init_env bndr of + Just (Var bndr') -> bndr' + Just other -> panic "decomposeRuleLhs" + Nothing -> bndr + + -- 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 + = case collectArgs (simpleSubst env body) of + (Var fn, args) -> Just (all_bndrs', fn, args) + other -> Nothing + +simpleSubst :: IdEnv CoreExpr -> CoreExpr -> CoreExpr +-- Similar to CoreSubst.substExpr, except that +-- (a) takes no account of capture; dictionary bindings use new names +-- (b) can have a GlobalId (imported) in its domain +-- (c) Ids only; no types are substituted + +simpleSubst subst expr + = go expr + where + go (Var v) = lookupVarEnv subst v `orElse` Var v + go (Type ty) = Type ty + go (Lit lit) = Lit lit + go (App fun arg) = App (go fun) (go arg) + go (Note note e) = Note note (go e) + go (Lam bndr body) = Lam bndr (go body) + go (Let (NonRec bndr rhs) body) = Let (NonRec bndr (go rhs)) (go body) + 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] + +addLocalInlines exports core_prs + = map add_inline core_prs + where + add_inline (bndr,rhs) | Just inl <- lookupVarEnv inline_env bndr + = addInlineInfo inl bndr rhs + | otherwise + = (bndr,rhs) + inline_env = mkVarEnv [(mono_id, prag) + | (_, _, mono_id, prags) <- exports, + InlinePrag prag <- prags] + +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} -If profiling and dealing with a dict binding, wrap the dict in "_scc_ DICT ": + +%************************************************************************ +%* * +\subsection[addAutoScc]{Adding automatic sccs} +%* * +%************************************************************************ \begin{code} -addDictScc var rhs - | not ( opt_SccProfilingOn || opt_AutoSccsOnAllToplevs) - -- the latter is so that -unprof-auto-scc-all adds dict sccs - || not (isDictTy (idType var)) - = returnDs rhs -- That's easy: do nothing +data AutoScc + = TopLevel + | TopLevelAddSccs (Id -> Maybe Id) + | NoSccs + +addSccs :: AutoScc -> [(a,Id,Id,[Prag])] -> AutoScc +addSccs auto_scc@(TopLevelAddSccs _) exports = auto_scc +addSccs NoSccs exports = NoSccs +addSccs TopLevel exports + = TopLevelAddSccs (\id -> case [ exp | (_,exp,loc,_) <- exports, loc == id ] of + (exp:_) | opt_AutoSccsOnAllToplevs || + (isExportedId exp && + opt_AutoSccsOnExportedToplevs) + -> Just exp + _ -> Nothing) + +addAutoScc :: AutoScc -- if needs be, decorate toplevs? + -> (Id, CoreExpr) + -> DsM (Id, CoreExpr) + +addAutoScc (TopLevelAddSccs auto_scc_fn) pair@(bndr, core_expr) + | do_auto_scc + = getModuleDs `thenDs` \ mod -> + returnDs (bndr, mkSCC (mkAutoCC top_bndr mod NotCafCC) core_expr) + where do_auto_scc = isJust maybe_auto_scc + maybe_auto_scc = auto_scc_fn bndr + (Just top_bndr) = maybe_auto_scc + +addAutoScc _ pair + = returnDs pair +\end{code} - | opt_CompilingGhcInternals - = returnDs (SCC prel_dicts_cc rhs) +If profiling and dealing with a dict binding, +wrap the dict in @_scc_ DICT @: + +\begin{code} +addDictScc var rhs = returnDs 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 | otherwise = getModuleAndGroupDs `thenDs` \ (mod, grp) -> - -- ToDo: do -dicts-all flag (mark dict things with individual CCs) - returnDs (SCC (mkAllDictsCC mod grp False) rhs) + returnDs (Note (SCC (mkAllDictsCC mod grp False)) rhs) +-} +\end{code} + + +%************************************************************************ +%* * + Desugaring coercions +%* * +%************************************************************************ -prel_dicts_cc = preludeDictsCostCentre False{-not dupd-} -- ditto + +\begin{code} +dsCoercion :: ExprCoFn -> DsM CoreExpr -> DsM CoreExpr +dsCoercion CoHole thing_inside = thing_inside +dsCoercion (CoCompose c1 c2) thing_inside = dsCoercion c1 (dsCoercion c2 thing_inside) +dsCoercion (CoLams ids c) thing_inside = do { expr <- dsCoercion c thing_inside + ; return (mkLams ids expr) } +dsCoercion (CoTyLams tvs c) thing_inside = do { expr <- dsCoercion c thing_inside + ; return (mkLams tvs expr) } +dsCoercion (CoApps c ids) thing_inside = do { expr <- dsCoercion c thing_inside + ; return (mkVarApps expr ids) } +dsCoercion (CoTyApps c tys) thing_inside = do { expr <- dsCoercion c thing_inside + ; return (mkTyApps expr tys) } +dsCoercion (CoLet bs c) thing_inside = do { prs <- dsLHsBinds bs + ; expr <- dsCoercion c thing_inside + ; return (Let (Rec prs) expr) } \end{code} + +