X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FbasicTypes%2FMkId.lhs;h=98425f149a2d1981737129d08ccf31c459149b46;hb=787b08bdea84cca4bf9490d87c059453bffc5ad2;hp=7060c803060a0f74bdad35849aa040cbe8dbe9fa;hpb=291f2adda098f7e275db3720ed07e7dc77c821c4;p=ghc-hetmet.git diff --git a/compiler/basicTypes/MkId.lhs b/compiler/basicTypes/MkId.lhs index 7060c80..98425f1 100644 --- a/compiler/basicTypes/MkId.lhs +++ b/compiler/basicTypes/MkId.lhs @@ -345,8 +345,8 @@ mkDataConIds wrap_name wkr_name data_con -- ...(let w = C x in ...(w p q)...)... -- we want to see that w is strict in its two arguments - wrap_unf = mkImplicitUnfolding $ Note InlineMe $ - mkLams wrap_tvs $ + wrap_unf = mkInlineRule InlSat wrap_rhs (length dict_args + length id_args) + wrap_rhs = mkLams wrap_tvs $ mkLams eq_args $ mkLams dict_args $ mkLams id_args $ foldr mk_case con_app @@ -460,12 +460,25 @@ mkDictSelId no_unf name clas info = noCafIdInfo `setArityInfo` 1 `setAllStrictnessInfo` Just strict_sig - `setUnfoldingInfo` (if no_unf then noUnfolding - else mkImplicitUnfolding rhs) + `setSpecInfo` mkSpecInfo [rule] + `setInlinePragInfo` neverInlinePragma + `setUnfoldingInfo` (if no_unf then noUnfolding + else mkImplicitUnfolding rhs) + -- Experimental: NOINLINE, so that their rule matches -- We no longer use 'must-inline' on record selectors. They'll -- inline like crazy if they scrutinise a constructor + n_ty_args = length tyvars + + -- This is the built-in rule that goes + -- op (dfT d1 d2) ---> opT d1 d2 + rule = BuiltinRule { ru_name = fsLit "Class op " `appendFS` + occNameFS (getOccName name) + , ru_fn = name + , ru_nargs = n_ty_args + 1 + , ru_try = dictSelRule index n_ty_args } + -- The strictness signature is of the form U(AAAVAAAA) -> T -- where the V depends on which item we are selecting -- It's worth giving one, so that absence info etc is generated @@ -480,7 +493,8 @@ mkDictSelId no_unf name clas tyvars = dataConUnivTyVars data_con arg_tys = {- ASSERT( isVanillaDataCon data_con ) -} dataConRepArgTys data_con eq_theta = dataConEqTheta data_con - the_arg_id = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` arg_ids) name + index = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` [0..]) name + the_arg_id = arg_ids !! index pred = mkClassPred clas (mkTyVarTys tyvars) dict_id = mkTemplateLocal 1 $ mkPredTy pred @@ -496,6 +510,20 @@ mkDictSelId no_unf name clas rhs_body | isNewTyCon tycon = unwrapNewTypeBody tycon (map mkTyVarTy tyvars) (Var dict_id) | otherwise = Case (Var dict_id) dict_id (idType the_arg_id) [(DataAlt data_con, eq_ids ++ arg_ids, Var the_arg_id)] + +dictSelRule :: Int -> Arity -> [CoreExpr] -> Maybe CoreExpr +-- Oh, very clever +-- op_i t1..tk (df s1..sn d1..dm) = op_i_helper s1..sn d1..dm +-- op_i t1..tk (D t1..tk op1 ... opm) = opi +-- +-- NB: the data constructor has the same number of type args as the class op + +dictSelRule index n_ty_args args + | (dict_arg : _) <- drop n_ty_args args + , Just (_, _, val_args) <- exprIsConApp_maybe dict_arg + = Just (val_args !! index) + | otherwise + = Nothing \end{code} @@ -825,8 +853,9 @@ mkDictFunId :: Name -- Name to use for the dict fun; -> Id mkDictFunId dfun_name inst_tyvars dfun_theta clas inst_tys - = mkExportedLocalVar DFunId dfun_name dfun_ty vanillaIdInfo + = mkExportedLocalVar (DFunId is_nt) dfun_name dfun_ty vanillaIdInfo where + is_nt = isNewTyCon (classTyCon clas) dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys) \end{code} @@ -905,6 +934,7 @@ seqId :: Id -- See Note [seqId magic] seqId = pcMiscPrelId seqName ty info where info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs + `setSpecInfo` mkSpecInfo [seq_cast_rule] ty = mkForAllTys [alphaTyVar,openBetaTyVar] @@ -912,6 +942,20 @@ seqId = pcMiscPrelId seqName ty info [x,y] = mkTemplateLocals [alphaTy, openBetaTy] rhs = mkLams [alphaTyVar,openBetaTyVar,x,y] (Case (Var x) x openBetaTy [(DEFAULT, [], Var y)]) + -- See Note [Built-in RULES for seq] + seq_cast_rule = BuiltinRule { ru_name = fsLit "seq of cast" + , ru_fn = seqName + , ru_nargs = 4 + , ru_try = match_seq_of_cast + } + +match_seq_of_cast :: [CoreExpr] -> Maybe CoreExpr + -- See Note [Built-in RULES for seq] +match_seq_of_cast [Type _, Type res_ty, Cast scrut co, expr] + = Just (Var seqId `mkApps` [Type (fst (coercionKind co)), Type res_ty, + scrut, expr]) +match_seq_of_cast _ = Nothing + ------------------------------------------------ lazyId :: Id -- See Note [lazyId magic] lazyId = pcMiscPrelId lazyIdName ty info @@ -932,10 +976,10 @@ b) Its fixity is set in LoadIface.ghcPrimIface c) It has quite a bit of desugaring magic. See DsUtils.lhs Note [Desugaring seq (1)] and (2) and (3) -d) There is some special rule handing: Note [RULES for seq] +d) There is some special rule handing: Note [User-defined RULES for seq] -Note [Rules for seq] -~~~~~~~~~~~~~~~~~~~~ +Note [User-defined RULES for seq] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Roman found situations where he had case (f n) of _ -> e where he knew that f (which was strict in n) would terminate if n did. @@ -957,6 +1001,20 @@ To make this work, we need to be careful that the magical desugaring done in Note [seqId magic] item (c) is *not* done on the LHS of a rule. Or rather, we arrange to un-do it, in DsBinds.decomposeRuleLhs. +Note [Built-in RULES for seq] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +We also have the following built-in rule for seq + + seq (x `cast` co) y = seq x y + +This eliminates unnecessary casts and also allows other seq rules to +match more often. Notably, + + seq (f x `cast` co) y --> seq (f x) y + +and now a user-defined rule for seq (see Note [User-defined RULES for seq]) +may fire. + Note [lazyId magic] ~~~~~~~~~~~~~~~~~~~