X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fstranal%2FWwLib.lhs;h=58800cdfaa518e5fa7564ebaa8bc1c4a5c226be5;hb=a237946da277f10bd3d223e5926d118044d24194;hp=06330549903d9672571ee69ea457625687a8170a;hpb=69e14f75a4b031e489b7774914e5a176409cea78;p=ghc-hetmet.git diff --git a/ghc/compiler/stranal/WwLib.lhs b/ghc/compiler/stranal/WwLib.lhs index 0633054..58800cd 100644 --- a/ghc/compiler/stranal/WwLib.lhs +++ b/ghc/compiler/stranal/WwLib.lhs @@ -5,63 +5,39 @@ \begin{code} module WwLib ( - WwBinding(..), - - worthSplitting, setUnpackStrategy, - mkWwBodies, mkWrapper + mkWwBodies, + worthSplitting, setUnpackStrategy ) where #include "HsVersions.h" import CoreSyn -import Id ( Id, idType, mkSysLocal, getIdDemandInfo, setIdDemandInfo, - mkWildId ) -import IdInfo ( CprInfo(..), noCprInfo ) -import Const ( Con(..), DataCon ) -import DataCon ( dataConArgTys ) -import Demand ( Demand(..) ) +import CoreUtils ( exprType ) +import Id ( Id, idType, mkSysLocal, idDemandInfo, setIdDemandInfo, + isOneShotLambda, setOneShotLambda, + mkWildId, setIdInfo + ) +import IdInfo ( CprInfo(..), noCprInfo, vanillaIdInfo ) +import DataCon ( DataCon, splitProductType ) +import Demand ( Demand(..), wwLazy, wwPrim ) import PrelInfo ( realWorldPrimId, aBSENT_ERROR_ID ) import TysPrim ( realWorldStatePrimTy ) -import TysWiredIn ( unboxedTupleCon, unboxedTupleTyCon ) -import Type ( isUnLiftedType, mkTyVarTys, mkTyVarTy, mkFunTys, - splitForAllTys, splitFunTysN, - splitAlgTyConApp_maybe, mkTyConApp, +import TysWiredIn ( tupleCon ) +import Type ( isUnLiftedType, + splitForAllTys, splitFunTys, isAlgType, + splitNewType_maybe, + mkTyConApp, mkFunTys, Type ) -import TyCon ( isNewTyCon, - TyCon ) -import BasicTypes ( NewOrData(..) ) -import Var ( TyVar ) +import BasicTypes ( NewOrData(..), Arity, Boxity(..) ) +import Var ( TyVar, Var, isId ) import UniqSupply ( returnUs, thenUs, getUniqueUs, getUniquesUs, mapUs, UniqSM ) -import Util ( zipWithEqual, zipEqual ) +import Util ( zipWithEqual, zipEqual, lengthExceeds ) import Outputable +import List ( zipWith4 ) \end{code} -%************************************************************************ -%* * -\subsection[datatype-WwLib]{@WwBinding@: a datatype for worker/wrapper-ing} -%* * -%************************************************************************ - -In the worker/wrapper stuff, we want to carry around @CoreBindings@ in -an ``intermediate form'' that can later be turned into a \tr{let} or -\tr{case} (depending on strictness info). - -\begin{code} -data WwBinding - = WwLet [CoreBind] - | WwCase (CoreExpr -> CoreExpr) - -- the "case" will be a "strict let" of the form: - -- - -- case rhs of - -- -> body - -- - -- (instead of "let = rhs in body") - -- - -- The expr you pass to the function is "body" (the - -- expression that goes "in the corner"). -\end{code} %************************************************************************ %* * @@ -207,10 +183,16 @@ nonAbsentArgs (d : ds) = 1 + nonAbsentArgs ds worthSplitting :: [Demand] -> Bool -- Result is bottom -> Bool -- True <=> the wrapper would not be an identity function -worthSplitting ds result_bot = not result_bot && any worth_it ds - -- Don't split if the result is bottom; there's no efficiency to - -- be gained, and (worse) the wrapper body may not look like a wrapper - -- body to getWorkerIdAndCons +worthSplitting ds result_bot = any worth_it ds + -- We used not to split if the result is bottom. + -- [Justification: there's no efficiency to be gained.] + -- But it's sometimes bad not to make a wrapper. Consider + -- fw = \x# -> let x = I# x# in case e of + -- p1 -> error_fn x + -- p2 -> error_fn x + -- p3 -> the real stuff + -- The re-boxing code won't go away unless error_fn gets a wrapper too. + where worth_it (WwLazy True) = True -- Absent arg worth_it (WwUnpack _ True _) = True -- Arg to unpack @@ -232,47 +214,148 @@ allAbsent ds = all absent ds %* * %************************************************************************ -@mkWrapper@ is called when importing a function. We have the type of -the function and the name of its worker, and we want to make its body (the wrapper). +@mkWwBodies@ is called when doing the worker/wrapper split inside a module. + +\begin{code} +mkWwBodies :: Type -- Type of original function + -> Arity -- Arity of original function + -> [Demand] -- Strictness of original function + -> Bool -- True <=> function returns bottom + -> [Bool] -- One-shot-ness of the function + -> CprInfo -- Result of CPR analysis + -> UniqSM ([Demand], -- Demands for worker (value) args + Id -> CoreExpr, -- Wrapper body, lacking only the worker Id + CoreExpr -> CoreExpr) -- Worker body, lacking the original function rhs + +mkWwBodies fun_ty arity demands res_bot one_shots cpr_info + = mkWWargs fun_ty arity demands' res_bot one_shots' `thenUs` \ (wrap_args, wrap_fn_args, work_fn_args, res_ty) -> + mkWWstr wrap_args `thenUs` \ (work_dmds, wrap_fn_str, work_fn_str) -> + mkWWcpr res_ty cpr_info `thenUs` \ (wrap_fn_cpr, work_fn_cpr, cpr_res_ty) -> + mkWWfixup cpr_res_ty work_dmds `thenUs` \ (final_work_dmds, wrap_fn_fixup, work_fn_fixup) -> + + returnUs (final_work_dmds, + Note InlineMe . wrap_fn_args . wrap_fn_cpr . wrap_fn_str . wrap_fn_fixup . Var, + work_fn_fixup . work_fn_str . work_fn_cpr . work_fn_args) + -- We use an INLINE unconditionally, even if the wrapper turns out to be + -- something trivial like + -- fw = ... + -- f = __inline__ (coerce T fw) + -- The point is to propagate the coerce to f's call sites, so even though + -- f's RHS is now trivial (size 1) we still want the __inline__ to prevent + -- fw from being inlined into f's RHS + where + demands' = demands ++ repeat wwLazy + one_shots' = one_shots ++ repeat False +\end{code} + + +%************************************************************************ +%* * +\subsection{Coercion stuff} +%* * +%************************************************************************ + + +We really want to "look through" coerces. +Reason: I've seen this situation: + + let f = coerce T (\s -> E) + in \x -> case x of + p -> coerce T' f + q -> \s -> E2 + r -> coerce T' f + +If only we w/w'd f, we'd get + let f = coerce T (\s -> fw s) + fw = \s -> E + in ... + +Now we'll inline f to get + + let fw = \s -> E + in \x -> case x of + p -> fw + q -> \s -> E2 + r -> fw + +Now we'll see that fw has arity 1, and will arity expand +the \x to get what we want. \begin{code} -mkWrapper :: Type -- Wrapper type - -> Int -- Arity - -> [Demand] -- Wrapper strictness info - -> CprInfo -- Wrapper cpr info - -> UniqSM (Id -> CoreExpr) -- Wrapper body, missing worker Id - -mkWrapper fun_ty arity demands cpr_info - = getUniquesUs arity `thenUs` \ wrap_uniqs -> +-- mkWWargs is driven off the function type and arity. +-- It chomps bites off foralls, arrows, newtypes +-- and keeps repeating that until it's satisfied the supplied arity + +mkWWargs :: Type -> Arity + -> [Demand] -> Bool -> [Bool] -- Both these will in due course be derived + -- from the type. The [Bool] is True for a one-shot arg. + -- ** Both are infinite, extended with neutral values if necy ** + -> UniqSM ([Var], -- Wrapper args + CoreExpr -> CoreExpr, -- Wrapper fn + CoreExpr -> CoreExpr, -- Worker fn + Type) -- Type of wrapper body + +mkWWargs fun_ty arity demands res_bot one_shots + | (res_bot || arity > 0) && (not (null tyvars) || n_arg_tys > 0) + -- If the function returns bottom, we feel free to + -- build lots of wrapper args: + -- \x. let v=E in \y. bottom + -- = \xy. let v=E in bottom + = getUniquesUs n_args `thenUs` \ wrap_uniqs -> let - (tyvars, tau_ty) = splitForAllTys fun_ty - (arg_tys, body_ty) = splitFunTysN "mkWrapper" arity tau_ty - -- The "expanding dicts" part here is important, even for the splitForAll - -- The imported thing might be a dictionary, such as Functor Foo - -- But Functor Foo = forall a b. (a->b) -> Foo a -> Foo b - -- and as such might have some strictness info attached. - -- Then we need to have enough args to zip to the strictness info - - wrap_args = zipWith mk_ww_local wrap_uniqs arg_tys + val_args = zipWith4 mk_wrap_arg wrap_uniqs arg_tys demands one_shots + wrap_args = tyvars ++ val_args in - mkWwBodies tyvars wrap_args body_ty demands cpr_info `thenUs` \ (wrap_fn, _, _) -> - returnUs wrap_fn + mkWWargs new_fun_ty + (arity - n_args) + (drop n_args demands) + res_bot + (drop n_args one_shots) `thenUs` \ (more_wrap_args, wrap_fn_args, work_fn_args, res_ty) -> + + returnUs (wrap_args ++ more_wrap_args, + mkLams wrap_args . wrap_fn_args, + work_fn_args . applyToVars wrap_args, + res_ty) + where + (tyvars, tau) = splitForAllTys fun_ty + (arg_tys, body_ty) = splitFunTys tau + n_arg_tys = length arg_tys + n_args | res_bot = n_arg_tys + | otherwise = arity `min` n_arg_tys + new_fun_ty | n_args == n_arg_tys = body_ty + | otherwise = mkFunTys (drop n_args arg_tys) body_ty + +mkWWargs fun_ty arity demands res_bot one_shots + = case splitNewType_maybe fun_ty of + Nothing -> returnUs ([], id, id, fun_ty) + Just rep_ty -> mkWWargs rep_ty arity demands res_bot one_shots `thenUs` \ (wrap_args, wrap_fn_args, work_fn_args, res_ty) -> + returnUs (wrap_args, + Note (Coerce fun_ty rep_ty) . wrap_fn_args, + work_fn_args . Note (Coerce rep_ty fun_ty), + res_ty) + + +applyToVars :: [Var] -> CoreExpr -> CoreExpr +applyToVars vars fn = mkVarApps fn vars + +mk_wrap_arg uniq ty dmd one_shot + = set_one_shot one_shot (setIdDemandInfo (mkSysLocal SLIT("w") uniq ty) dmd) + where + set_one_shot True id = setOneShotLambda id + set_one_shot False id = id \end{code} -@mkWwBodies@ is called when doing the worker/wrapper split inside a module. + +%************************************************************************ +%* * +\subsection{Fixup stuff} +%* * +%************************************************************************ \begin{code} -mkWwBodies :: [TyVar] -> [Id] -> Type -- Original fn args and body type - -> [Demand] -- Strictness info for original fn; corresp 1-1 with args - -> CprInfo -- Result of CPR analysis - -> UniqSM (Id -> CoreExpr, -- Wrapper body, lacking only the worker Id - CoreExpr -> CoreExpr, -- Worker body, lacking the original function body - [Demand]) -- Strictness info for worker - -mkWwBodies tyvars args body_ty demands cpr_info - | allAbsent demands && - isUnLiftedType body_ty - = -- Horrid special case. If the worker would have no arguments, and the +mkWWfixup res_ty work_dmds + | null work_dmds && isUnLiftedType res_ty + -- Horrid special case. If the worker would have no arguments, and the -- function returns a primitive type value, that would make the worker into -- an unboxed value. We box it by passing a dummy void argument, thus: -- @@ -280,103 +363,98 @@ mkWwBodies tyvars args body_ty demands cpr_info -- fw = /\abc. \v. body -- -- We use the state-token type which generates no code - getUniqueUs `thenUs` \ void_arg_uniq -> + = getUniqueUs `thenUs` \ void_arg_uniq -> let - void_arg = mk_ww_local void_arg_uniq realWorldStatePrimTy + void_arg = mk_ww_local void_arg_uniq realWorldStatePrimTy in - returnUs (\ work_id -> Note InlineMe $ -- Inline the wrapper - mkLams tyvars $ mkLams args $ - mkApps (Var work_id) - (map (Type . mkTyVarTy) tyvars ++ [Var realWorldPrimId]), - \ body -> mkLams (tyvars ++ [void_arg]) body, - [WwLazy True]) - -mkWwBodies tyvars wrap_args body_ty demands cpr_info - | otherwise - = let - -- demands may be longer than number of args. If we aren't doing w/w - -- for strictness then demands is an infinite list of 'lazy' args. - wrap_args_w_demands = zipWith setIdDemandInfo wrap_args demands - in - mkWW wrap_args_w_demands `thenUs` \ (wrap_fn, work_args_w_demands, work_fn) -> - - mkWWcpr body_ty cpr_info `thenUs` \ (wrap_fn_w_cpr, work_fn_w_cpr) -> + returnUs ([wwPrim], + \ call_to_worker -> App call_to_worker (Var realWorldPrimId), + \ worker_body -> Lam void_arg worker_body) - returnUs (\ work_id -> Note InlineMe $ - mkLams tyvars $ mkLams wrap_args_w_demands $ - (wrap_fn_w_cpr . wrap_fn) (mkTyApps (Var work_id) (mkTyVarTys tyvars)), - - \ body -> mkLams tyvars $ mkLams work_args_w_demands $ - (work_fn_w_cpr . work_fn) body, + | otherwise + = returnUs (work_dmds, id, id) +\end{code} - map getIdDemandInfo work_args_w_demands) -\end{code} +%************************************************************************ +%* * +\subsection{Strictness stuff} +%* * +%************************************************************************ \begin{code} -mkWW :: [Id] -- Wrapper args; have their demand info on them - -> UniqSM (CoreExpr -> CoreExpr, -- Wrapper body, lacking the inner call to the worker - -- and without its lambdas - [Id], -- Worker args; have their demand info on them - CoreExpr -> CoreExpr) -- Worker body, lacking the original body of the function +mkWWstr :: [Var] -- Wrapper args; have their demand info on them + -- *Includes type variables* + -> UniqSM ([Demand], -- Demand on worker (value) args + CoreExpr -> CoreExpr, -- Wrapper body, lacking the worker call + -- and without its lambdas + -- This fn adds the unboxing, and makes the + -- call passing the unboxed things + + CoreExpr -> CoreExpr) -- Worker body, lacking the original body of the function, + -- but *with* lambdas +mkWWstr wrap_args + = mk_ww_str wrap_args `thenUs` \ (work_args, wrap_fn, work_fn) -> + returnUs ( [idDemandInfo v | v <- work_args, isId v], + \ wrapper_body -> wrap_fn (mkVarApps wrapper_body work_args), + \ worker_body -> mkLams work_args (work_fn worker_body)) -- Empty case -mkWW [] - = returnUs (\ wrapper_body -> wrapper_body, - [], +mk_ww_str [] + = returnUs ([], + \ wrapper_body -> wrapper_body, \ worker_body -> worker_body) -mkWW (arg : ds) - = case getIdDemandInfo arg of +mk_ww_str (arg : ds) + | isTyVar arg + = mk_ww_str ds `thenUs` \ (worker_args, wrap_fn, work_fn) -> + returnUs (arg : worker_args, wrap_fn, work_fn) + + | otherwise + = case idDemandInfo arg of -- Absent case WwLazy True -> - mkWW ds `thenUs` \ (wrap_fn, worker_args, work_fn) -> - returnUs (\ wrapper_body -> wrap_fn wrapper_body, - worker_args, - \ worker_body -> mk_absent_let arg (work_fn worker_body)) - + mk_ww_str ds `thenUs` \ (worker_args, wrap_fn, work_fn) -> + returnUs (worker_args, wrap_fn, mk_absent_let arg . work_fn) -- Unpack case WwUnpack new_or_data True cs -> getUniquesUs (length inst_con_arg_tys) `thenUs` \ uniqs -> let unpk_args = zipWith mk_ww_local uniqs inst_con_arg_tys - unpk_args_w_ds = zipWithEqual "mkWW" setIdDemandInfo unpk_args cs + unpk_args_w_ds = zipWithEqual "mk_ww_str" set_worker_arg_info unpk_args cs in - mkWW (unpk_args_w_ds ++ ds) `thenUs` \ (wrap_fn, worker_args, work_fn) -> - returnUs (\ wrapper_body -> mk_unpk_case new_or_data arg unpk_args data_con arg_tycon - (wrap_fn wrapper_body), - worker_args, - \ worker_body -> work_fn (mk_pk_let new_or_data arg data_con - tycon_arg_tys unpk_args worker_body)) + mk_ww_str (unpk_args_w_ds ++ ds) `thenUs` \ (worker_args, wrap_fn, work_fn) -> + returnUs (worker_args, + mk_unpk_case new_or_data arg unpk_args data_con arg_tycon . wrap_fn, + work_fn . mk_pk_let new_or_data arg data_con tycon_arg_tys unpk_args) where - inst_con_arg_tys = dataConArgTys data_con tycon_arg_tys - (arg_tycon, tycon_arg_tys, data_con) - = case (splitAlgTyConApp_maybe (idType arg)) of + (arg_tycon, tycon_arg_tys, data_con, inst_con_arg_tys) = splitProductType "mk_ww_str" (idType arg) - Just (arg_tycon, tycon_arg_tys, [data_con]) -> - -- The main event: a single-constructor data type - (arg_tycon, tycon_arg_tys, data_con) + -- Other cases + other_demand -> + mk_ww_str ds `thenUs` \ (worker_args, wrap_fn, work_fn) -> + returnUs (arg : worker_args, wrap_fn, work_fn) + where + -- If the wrapper argument is a one-shot lambda, then + -- so should (all) the corresponding worker arguments be + -- This bites when we do w/w on a case join point + set_worker_arg_info worker_arg demand = set_one_shot (setIdDemandInfo worker_arg demand) - Just (_, _, data_cons) -> - pprPanic "mk_ww_arg_processing:" - (text "not one constr (interface files not consistent/up to date?)" - $$ (ppr arg <+> ppr (idType arg))) + set_one_shot | isOneShotLambda arg = setOneShotLambda + | otherwise = \x -> x +\end{code} - Nothing -> - panic "mk_ww_arg_processing: not datatype" +%************************************************************************ +%* * +\subsection{CPR stuff} +%* * +%************************************************************************ - -- Other cases - other_demand -> - mkWW ds `thenUs` \ (wrap_fn, worker_args, work_fn) -> - returnUs (\ wrapper_body -> wrap_fn (App wrapper_body (Var arg)), - arg : worker_args, - work_fn) -\end{code} @mkWWcpr@ takes the worker/wrapper pair produced from the strictness info and adds in the CPR transformation. The worker returns an @@ -391,153 +469,45 @@ left-to-right traversal of the result structure. mkWWcpr :: Type -- function body type -> CprInfo -- CPR analysis results -> UniqSM (CoreExpr -> CoreExpr, -- New wrapper - CoreExpr -> CoreExpr) -- New worker + CoreExpr -> CoreExpr, -- New worker + Type) -- Type of worker's body mkWWcpr body_ty NoCPRInfo - = returnUs (id, id) -- Must be just the strictness transf. -mkWWcpr body_ty (CPRInfo cpr_args) - = getUniqueUs `thenUs` \ body_arg_uniq -> - let - body_var = mk_ww_local body_arg_uniq body_ty - in - cpr_reconstruct body_ty cpr_info' `thenUs` \reconst_fn -> - cpr_flatten body_ty cpr_info' `thenUs` \flatten_fn -> - returnUs (reconst_fn, flatten_fn) - where - -- We only make use of the outer level of CprInfo, otherwise we - -- may lose laziness. :-( Hopefully, we will find a use for the - -- extra info some day (e.g. creating versions specialized to - -- the use made of the components of the result by the callee) - cpr_info' = CPRInfo (map (const NoCPRInfo) cpr_args) -\end{code} - + = returnUs (id, id, body_ty) -- Must be just the strictness transf. -@cpr_flatten@ takes the result type produced by the body and the info -from the CPR analysis and flattens the constructed product components. -These are returned in an unboxed tuple. +mkWWcpr body_ty ReturnsCPR + | not (isAlgType body_ty) + = WARN( True, text "mkWWcpr: non-algebraic body type" <+> ppr body_ty ) + returnUs (id, id, body_ty) -\begin{code} -cpr_flatten :: Type -> CprInfo -> UniqSM (CoreExpr -> CoreExpr) -cpr_flatten ty cpr_info - = mk_cpr_case (ty, cpr_info) `thenUs` \(res_id, tup_ids, flatten_exp) -> - returnUs (\body -> Case body res_id - [(DEFAULT, [], flatten_exp (fst $ mk_unboxed_tuple tup_ids))]) - - - -mk_cpr_case :: (Type, CprInfo) -> - UniqSM (CoreBndr, -- Name of binder for this part of result - [(CoreExpr, Type)], -- expressions for flattened result - CoreExpr -> CoreExpr) -- add in code to flatten result - -mk_cpr_case (ty, NoCPRInfo) - -- this component must be returned as a component of the unboxed tuple result - = getUniqueUs `thenUs` \id_uniq -> - let id_id = mk_ww_local id_uniq ty in - returnUs (id_id, [(Var id_id, ty)], id) -mk_cpr_case (ty, cpr_info@(CPRInfo ci_args)) - | isNewTyCon tycon -- a new type: under the coercions must be a - -- constructed product - = ASSERT ( null $ tail inst_con_arg_tys ) - mk_cpr_case (head inst_con_arg_tys, cpr_info) - `thenUs` \(arg, tup, exp) -> - getUniqueUs `thenUs` \id_uniq -> - let id_id = mk_ww_local id_uniq ty - new_exp_case = \var -> Case (Note (Coerce (idType arg) ty) (Var id_id)) - arg - [(DEFAULT,[], exp var)] - in - returnUs (id_id, tup, new_exp_case) - - | otherwise -- a data type - -- flatten components - = mapUs mk_cpr_case (zip inst_con_arg_tys ci_args) - `thenUs` \sub_builds -> - getUniqueUs `thenUs` \id_uniq -> - let id_id = mk_ww_local id_uniq ty - (args, tup, exp) = unzip3 sub_builds - con_app = mkConApp data_con (map Var args) - new_tup = concat tup - new_exp_case = \var -> Case (Var id_id) (mkWildId ty) - [(DataCon data_con, args, - foldl (\e f -> f e) var exp)] + | n_con_args == 1 && isUnLiftedType con_arg_ty1 + -- Special case when there is a single result of unlifted type + = getUniquesUs 2 `thenUs` \ [work_uniq, arg_uniq] -> + let + work_wild = mk_ww_local work_uniq body_ty + arg = mk_ww_local arg_uniq con_arg_ty1 in - returnUs (id_id, new_tup, new_exp_case) - where - (data_con, tycon, tycon_arg_tys, inst_con_arg_tys) = splitType "mk_cpr_case" ty - -\end{code} + returnUs (\ wkr_call -> Case wkr_call arg [(DEFAULT, [], mkConApp data_con (map Type tycon_arg_tys ++ [Var arg]))], + \ body -> Case body work_wild [(DataAlt data_con, [arg], Var arg)], + con_arg_ty1) -@cpr_reconstruct@ does the opposite of @cpr_flatten@. It takes the unboxed -tuple produced by the worker and reconstructs the structured result. - -\begin{code} -cpr_reconstruct :: Type -> CprInfo -> UniqSM (CoreExpr -> CoreExpr) -cpr_reconstruct ty cpr_info - = mk_cpr_let (ty,cpr_info) `thenUs` \(res_id, tup_ids, reconstruct_exp) -> - returnUs (\worker -> Case worker (mkWildId $ worker_type tup_ids) - [(DataCon $ unboxedTupleCon $ length tup_ids, - tup_ids, reconstruct_exp $ Var res_id)]) - - where - worker_type ids = mkTyConApp (unboxedTupleTyCon (length ids)) (map idType ids) - - -mk_cpr_let :: (Type, CprInfo) -> - UniqSM (CoreBndr, -- Binder for this component of result - [CoreBndr], -- Binders which will appear in worker's result - CoreExpr -> CoreExpr) -- Code to produce structured result. -mk_cpr_let (ty, NoCPRInfo) - -- this component will appear explicitly in the unboxed tuple. - = getUniqueUs `thenUs` \id_uniq -> + | otherwise -- The general case + = getUniquesUs (n_con_args + 2) `thenUs` \ uniqs -> let - id_id = mk_ww_local id_uniq ty - in - returnUs (id_id, [id_id], id) - -mk_cpr_let (ty, cpr_info@(CPRInfo ci_args)) - | isNewTyCon tycon -- a new type: must coerce the argument to this type - = ASSERT ( null $ tail inst_con_arg_tys ) - mk_cpr_let (head inst_con_arg_tys, cpr_info) - `thenUs` \(arg, tup, exp) -> - getUniqueUs `thenUs` \id_uniq -> - let id_id = mk_ww_local id_uniq ty - new_exp = \var -> exp (Let (NonRec id_id (Note (Coerce ty (idType arg)) (Var arg))) var) - in - returnUs (id_id, tup, new_exp) - - | otherwise -- a data type - -- reconstruct components then apply data con - = mapUs mk_cpr_let (zip inst_con_arg_tys ci_args) - `thenUs` \sub_builds -> - getUniqueUs `thenUs` \id_uniq -> - let id_id = mk_ww_local id_uniq ty - (args, tup, exp) = unzip3 sub_builds - con_app = mkConApp data_con $ (map Type tycon_arg_tys) ++ (map Var args) - new_tup = concat tup - new_exp = \var -> foldl (\e f -> f e) (Let (NonRec id_id con_app) var) exp + (wrap_wild : work_wild : args) = zipWith mk_ww_local uniqs (ubx_tup_ty : body_ty : con_arg_tys) + arg_vars = map Var args + ubx_tup_con = tupleCon Unboxed n_con_args + ubx_tup_ty = exprType ubx_tup_app + ubx_tup_app = mkConApp ubx_tup_con (map Type con_arg_tys ++ arg_vars) + con_app = mkConApp data_con (map Type tycon_arg_tys ++ arg_vars) in - returnUs (id_id, new_tup, new_exp) + returnUs (\ wkr_call -> Case wkr_call wrap_wild [(DataAlt ubx_tup_con, args, con_app)], + \ body -> Case body work_wild [(DataAlt data_con, args, ubx_tup_app)], + ubx_tup_ty) where - (data_con, tycon, tycon_arg_tys, inst_con_arg_tys) = splitType "mk_cpr_let" ty - -splitType :: String -> Type -> (DataCon, TyCon, [Type], [Type]) -splitType fname ty = (data_con, tycon, tycon_arg_tys, dataConArgTys data_con tycon_arg_tys) - where - (data_con, tycon, tycon_arg_tys) - = case (splitAlgTyConApp_maybe ty) of - Just (arg_tycon, tycon_arg_tys, [data_con]) -> - -- The main event: a single-constructor data type - (data_con, arg_tycon, tycon_arg_tys) - - Just (_, _, data_cons) -> - pprPanic (fname ++ ":") - (text "not one constr (interface files not consistent/up to date?)" - $$ ppr ty) - - Nothing -> - pprPanic (fname ++ ":") - (text "not a datatype" $$ ppr ty) + (tycon, tycon_arg_tys, data_con, con_arg_tys) = splitProductType "mkWWcpr" body_ty + n_con_args = length con_arg_tys + con_arg_ty1 = head con_arg_tys \end{code} @@ -561,14 +531,27 @@ mk_unpk_case NewType arg unpk_args boxing_con boxing_tycon body -- A newtype! Use a coercion not a case = ASSERT( null other_args ) Case (Note (Coerce (idType unpk_arg) (idType arg)) (Var arg)) - unpk_arg + (sanitiseCaseBndr unpk_arg) [(DEFAULT,[],body)] where (unpk_arg:other_args) = unpk_args mk_unpk_case DataType arg unpk_args boxing_con boxing_tycon body -- A data type - = Case (Var arg) arg [(DataCon boxing_con, unpk_args, body)] + = Case (Var arg) + (sanitiseCaseBndr arg) + [(DataAlt boxing_con, unpk_args, body)] + +sanitiseCaseBndr :: Id -> Id +-- The argument we are scrutinising has the right type to be +-- a case binder, so it's convenient to re-use it for that purpose. +-- But we *must* throw away all its IdInfo. In particular, the argument +-- will have demand info on it, and that demand info may be incorrect for +-- the case binder. e.g. case ww_arg of ww_arg { I# x -> ... } +-- Quite likely ww_arg isn't used in '...'. The case may get discarded +-- if the case binder says "I'm demanded". This happened in a situation +-- like (x+y) `seq` .... +sanitiseCaseBndr id = id `setIdInfo` vanillaIdInfo mk_pk_let NewType arg boxing_con con_tys unpk_args body = ASSERT( null other_args ) @@ -577,21 +560,11 @@ mk_pk_let NewType arg boxing_con con_tys unpk_args body (unpk_arg:other_args) = unpk_args mk_pk_let DataType arg boxing_con con_tys unpk_args body - = Let (NonRec arg (Con (DataCon boxing_con) con_args)) body + = Let (NonRec arg (mkConApp boxing_con con_args)) body where con_args = map Type con_tys ++ map Var unpk_args mk_ww_local uniq ty = mkSysLocal SLIT("ww") uniq ty - -mk_unboxed_tuple :: [(CoreExpr, Type)] -> (CoreExpr, Type) -mk_unboxed_tuple contents - = (mkConApp (unboxedTupleCon (length contents)) - (map (Type . snd) contents ++ - map fst contents), - mkTyConApp (unboxedTupleTyCon (length contents)) - (map snd contents)) - - \end{code}