X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FDesugar.lhs;h=3b30deaa2e89c1643b43c7d17da898e62557aebc;hb=cad6d4688bdc309b3e9953bf091535a8eeaa2515;hp=6842e9d6d624ac49846b191e7b96fda240d13bf7;hpb=fcf5ff34649982a99bc1e4a4940453a181a8d899;p=ghc-hetmet.git diff --git a/compiler/deSugar/Desugar.lhs b/compiler/deSugar/Desugar.lhs index 6842e9d..3b30dea 100644 --- a/compiler/deSugar/Desugar.lhs +++ b/compiler/deSugar/Desugar.lhs @@ -17,7 +17,6 @@ import MkIface import Id import Name import CoreSyn -import OccurAnal import PprCore import DsMonad import DsExpr @@ -28,10 +27,8 @@ import DsExpr () -- Forces DsExpr to be compiled; DsBinds only import Module import RdrName import NameSet -import VarSet import Rules -import CoreLint -import CoreFVs +import CoreMonad ( endPass ) import ErrUtils import Outputable import SrcLoc @@ -40,7 +37,6 @@ import FastString import Coverage import Data.IORef -import Data.Char \end{code} %************************************************************************ @@ -50,7 +46,8 @@ import Data.Char %************************************************************************ \begin{code} -deSugar :: HscEnv -> ModLocation -> TcGblEnv -> IO (Maybe ModGuts) +-- | Main entry point to the desugarer. +deSugar :: HscEnv -> ModLocation -> TcGblEnv -> IO (Messages, Maybe ModGuts) -- Can modify PCS by faulting in more declarations deSugar hsc_env @@ -65,7 +62,8 @@ deSugar hsc_env tcg_fix_env = fix_env, tcg_inst_env = inst_env, tcg_fam_inst_env = fam_inst_env, - tcg_deprecs = deprecs, + tcg_warns = warns, + tcg_anns = anns, tcg_binds = binds, tcg_fords = fords, tcg_rules = rules, @@ -78,32 +76,36 @@ deSugar hsc_env -- Desugar the program ; let export_set = availsToNameSet exports - ; let auto_scc = mkAutoScc mod export_set + ; let auto_scc = mkAutoScc dflags mod export_set ; let target = hscTarget dflags ; let hpcInfo = emptyHpcInfo other_hpc_info - ; mb_res <- case target of - HscNothing -> return (Just ([], [], NoStubs, hpcInfo, emptyModBreaks)) - _ -> do (binds_cvr,ds_hpc_info, modBreaks) - <- if (opt_Hpc - || target == HscInterpreted) - && (not (isHsBoot hsc_src)) - then addCoverageTicksToBinds dflags mod mod_loc (typeEnvTyCons type_env) binds - else return (binds, hpcInfo, emptyModBreaks) - initDs hsc_env mod rdr_env type_env $ do - { core_prs <- dsTopLHsBinds auto_scc binds_cvr - ; (ds_fords, foreign_prs) <- dsForeigns fords - ; let all_prs = foreign_prs ++ core_prs - ; ds_rules <- mapM dsRule rules - ; return (all_prs, catMaybes ds_rules, ds_fords, ds_hpc_info, modBreaks) - } + ; (msgs, mb_res) + <- case target of + HscNothing -> + return (emptyMessages, + Just ([], [], NoStubs, hpcInfo, emptyModBreaks)) + _ -> do + (binds_cvr,ds_hpc_info, modBreaks) + <- if (opt_Hpc + || target == HscInterpreted) + && (not (isHsBoot hsc_src)) + then addCoverageTicksToBinds dflags mod mod_loc (typeEnvTyCons type_env) binds + else return (binds, hpcInfo, emptyModBreaks) + initDs hsc_env mod rdr_env type_env $ do + core_prs <- dsTopLHsBinds auto_scc binds_cvr + (ds_fords, foreign_prs) <- dsForeigns fords + let all_prs = foreign_prs ++ core_prs + ds_rules <- mapM dsRule rules + return (all_prs, catMaybes ds_rules, ds_fords, ds_hpc_info, modBreaks) + ; case mb_res of { - Nothing -> return Nothing ; + Nothing -> return (msgs, Nothing) ; Just (all_prs, ds_rules, ds_fords,ds_hpc_info, modBreaks) -> do { -- Add export flags to bindings keep_alive <- readIORef keep_var ; let final_prs = addExportFlags target export_set - keep_alive all_prs ds_rules + keep_alive all_prs ds_binds = [Rec final_prs] -- Notice that we put the whole lot in a big Rec, even the foreign binds -- When compiling PrelFloat, which defines data Float = F# Float# @@ -112,7 +114,7 @@ deSugar hsc_env -- things into the in-scope set before simplifying; so we get no unfolding for F#! -- Lint result if necessary - ; endPass dflags "Desugar" Opt_D_dump_ds ds_binds + ; endPass dflags "Desugar" Opt_D_dump_ds ds_binds ds_rules -- Dump output ; doIfSet (dopt Opt_D_dump_ds dflags) @@ -130,7 +132,8 @@ deSugar hsc_env mg_dir_imps = imp_mods imports, mg_rdr_env = rdr_env, mg_fix_env = fix_env, - mg_deprecs = deprecs, + mg_warns = warns, + mg_anns = anns, mg_types = type_env, mg_insts = insts, mg_fam_insts = fam_insts, @@ -143,19 +146,21 @@ deSugar hsc_env mg_modBreaks = modBreaks, mg_vect_info = noVectInfo } - ; return (Just mod_guts) + ; return (msgs, Just mod_guts) }}} -mkAutoScc :: Module -> NameSet -> AutoScc -mkAutoScc mod exports +mkAutoScc :: DynFlags -> Module -> NameSet -> AutoScc +mkAutoScc dflags mod exports | not opt_SccProfilingOn -- No profiling = NoSccs - | opt_AutoSccsOnAllToplevs -- Add auto-scc on all top-level things + -- Add auto-scc on all top-level things + | dopt Opt_AutoSccsOnAllToplevs dflags = AddSccs mod (\id -> not $ isDerivedOccName $ getOccName id) -- See #1641. This is pretty yucky, but I can't see a better way -- to identify compiler-generated Ids, and at least this should -- catch them all. - | opt_AutoSccsOnExportedToplevs -- Only on exported things + -- Only on exported things + | dopt Opt_AutoSccsOnExportedToplevs dflags = AddSccs mod (\id -> idName id `elemNameSet` exports) | otherwise = NoSccs @@ -163,25 +168,25 @@ mkAutoScc mod exports deSugarExpr :: HscEnv -> Module -> GlobalRdrEnv -> TypeEnv -> LHsExpr Id - -> IO (Maybe CoreExpr) + -> IO (Messages, Maybe CoreExpr) -- Prints its own errors; returns Nothing if error occurred -deSugarExpr hsc_env this_mod rdr_env type_env tc_expr - = do { let dflags = hsc_dflags hsc_env - ; showPass dflags "Desugar" +deSugarExpr hsc_env this_mod rdr_env type_env tc_expr = do + let dflags = hsc_dflags hsc_env + showPass dflags "Desugar" - -- Do desugaring - ; mb_core_expr <- initDs hsc_env this_mod rdr_env type_env $ - dsLExpr tc_expr + -- Do desugaring + (msgs, mb_core_expr) <- initDs hsc_env this_mod rdr_env type_env $ + dsLExpr tc_expr - ; case mb_core_expr of { - Nothing -> return Nothing ; - Just expr -> do { + case mb_core_expr of + Nothing -> return (msgs, Nothing) + Just expr -> do - -- Dump output - dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr expr) + -- Dump output + dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr expr) - ; return (Just expr) } } } + return (msgs, Just expr) -- addExportFlags -- Set the no-discard flag if either @@ -199,26 +204,17 @@ deSugarExpr hsc_env this_mod rdr_env type_env tc_expr -- it's just because the type checker is rather busy already and -- I didn't want to pass in yet another mapping. -addExportFlags :: HscTarget -> NameSet -> NameSet -> [(Id, t)] -> [CoreRule] +addExportFlags :: HscTarget -> NameSet -> NameSet -> [(Id, t)] -> [(Id, t)] -addExportFlags target exports keep_alive prs rules +addExportFlags target exports keep_alive prs = [(add_export bndr, rhs) | (bndr,rhs) <- prs] where add_export bndr | dont_discard bndr = setIdExported bndr | otherwise = bndr - orph_rhs_fvs = unionVarSets [ ruleRhsFreeVars rule - | rule <- rules, - not (isLocalRule rule) ] - -- A non-local rule keeps alive the free vars of its right-hand side. - -- (A "non-local" is one whose head function is not locally defined.) - -- Local rules are (later, after gentle simplification) - -- attached to the Id, and that keeps the rhs free vars alive. - dont_discard bndr = is_exported name || name `elemNameSet` keep_alive - || bndr `elemVarSet` orph_rhs_fvs where name = idName bndr @@ -236,7 +232,7 @@ addExportFlags target exports keep_alive prs rules ppr_ds_rules :: [CoreRule] -> SDoc ppr_ds_rules [] = empty ppr_ds_rules rules - = text "" $$ text "-------------- DESUGARED RULES -----------------" $$ + = blankLine $$ text "-------------- DESUGARED RULES -----------------" $$ pprRules rules \end{code} @@ -252,29 +248,38 @@ ppr_ds_rules rules dsRule :: LRuleDecl Id -> DsM (Maybe CoreRule) dsRule (L loc (HsRule name act vars lhs _tv_lhs rhs _fv_rhs)) = putSrcSpanDs loc $ - do { let bndrs = [var | RuleBndr (L _ var) <- vars] - ; lhs' <- dsLExpr lhs + do { let bndrs' = [var | RuleBndr (L _ var) <- vars] + + ; lhs' <- unsetOptM Opt_EnableRewriteRules $ + dsLExpr lhs -- Note [Desugaring RULE lhss] + ; rhs' <- dsLExpr rhs - ; case decomposeRuleLhs (occurAnalyseExpr lhs') of { - Nothing -> do { warnDs msg; return Nothing } ; - Just (fn_id, args) -> do - -- Substitute the dict bindings eagerly, -- and take the body apart into a (f args) form + ; case decomposeRuleLhs (mkLams bndrs' lhs') of { + Nothing -> do { warnDs msg; return Nothing } ; + Just (bndrs, fn_id, args) -> do + { let local_rule = isLocalId fn_id -- NB: isLocalId is False of implicit Ids. This is good becuase -- we don't want to attach rules to the bindings of implicit Ids, -- because they don't show up in the bindings until just before code gen - fn_name = idName fn_id - - rule = Rule { ru_name = name, ru_fn = fn_name, ru_act = act, - ru_bndrs = bndrs, ru_args = args, ru_rhs = rhs', - ru_rough = roughTopNames args, - ru_local = local_rule } + fn_name = idName fn_id + rule = mkRule local_rule name act fn_name bndrs args rhs' ; return (Just rule) } } } where msg = hang (ptext (sLit "RULE left-hand side too complicated to desugar; ignored")) 2 (ppr lhs) \end{code} + +Note [Desugaring RULE left hand sides] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +For the LHS of a RULE we do *not* want to desugar + [x] to build (\cn. x `c` n) +We want to leave explicit lists simply as chains +of cons's. We can achieve that slightly indirectly by +switching off EnableRewriteRules. See DsExpr.dsExplicitList. + +That keeps the desugaring of list comprehensions simple too.