X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDesugar.lhs;h=be5ad1e544d291677875c99826858b43298da58a;hb=2909e581ddf0162ad2c113e17a8f19991862b89c;hp=67c6261ebe68eb4c8516cd7c8c454e8f6b12ea52;hpb=98688c6e8fd33f31c51218cf93cbf03fe3a5e73d;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/Desugar.lhs b/ghc/compiler/deSugar/Desugar.lhs index 67c6261..be5ad1e 100644 --- a/ghc/compiler/deSugar/Desugar.lhs +++ b/ghc/compiler/deSugar/Desugar.lhs @@ -8,41 +8,43 @@ module Desugar ( deSugar, deSugarExpr ) where #include "HsVersions.h" -import CmdLineOpts ( DynFlag(..), dopt, opt_SccProfilingOn ) -import HscTypes ( ModGuts(..), ModGuts, HscEnv(..), - Dependencies(..), TypeEnv, - unQualInScope ) -import HsSyn ( MonoBinds, RuleDecl(..), RuleBndr(..), - HsExpr(..), HsBinds(..), MonoBinds(..) ) -import TcHsSyn ( TypecheckedRuleDecl, TypecheckedHsExpr ) +import DynFlags ( DynFlag(..), DynFlags(..), dopt, GhcMode(..) ) +import StaticFlags ( opt_SccProfilingOn ) +import DriverPhases ( isHsBoot ) +import HscTypes ( ModGuts(..), HscEnv(..), + Dependencies(..), TypeEnv, IsBootInterface ) +import HsSyn ( RuleDecl(..), RuleBndr(..), LHsExpr, LRuleDecl ) import TcRnTypes ( TcGblEnv(..), ImportAvails(..) ) import MkIface ( mkUsageInfo ) -import Id ( Id ) +import Id ( Id, setIdExported, idName ) +import Name ( Name, isExternalName, nameIsLocalOrFrom, nameOccName ) import CoreSyn -import PprCore ( pprIdRules, pprCoreExpr ) -import Subst ( substExpr, mkSubst, mkInScopeSet ) +import PprCore ( pprRules, pprCoreExpr ) import DsMonad -import DsExpr ( dsExpr ) -import DsBinds ( dsMonoBinds, AutoScc(..) ) +import DsExpr ( dsLExpr ) +import DsBinds ( dsTopLHsBinds, decomposeRuleLhs, AutoScc(..) ) import DsForeign ( dsForeigns ) import DsExpr () -- Forces DsExpr to be compiled; DsBinds only -- depends on DsExpr.hi-boot. -import Module ( Module, moduleEnvElts, emptyModuleEnv ) -import Id ( Id ) +import Module ( Module, moduleEnvElts, delModuleEnv, moduleFS ) import RdrName ( GlobalRdrEnv ) import NameSet -import VarEnv import VarSet -import Bag ( isEmptyBag, mapBag, emptyBag ) +import Bag ( Bag, isEmptyBag, emptyBag ) +import Rules ( roughTopNames ) import CoreLint ( showPass, endPass ) +import CoreFVs ( ruleRhsFreeVars, exprsFreeNames ) +import Packages ( PackageState(thPackageId), PackageIdH(..) ) import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings, - addShortWarnLocLine, errorsFound ) + errorsFound, WarnMsg ) +import ListSetOps ( insertList ) import Outputable -import qualified Pretty import UniqSupply ( mkSplitUniqSupply ) -import SrcLoc ( SrcLoc ) +import SrcLoc ( Located(..) ) import DATA_IOREF ( readIORef ) +import Maybes ( catMaybes ) import FastString +import Util ( sortLe ) \end{code} %************************************************************************ @@ -52,63 +54,104 @@ import FastString %************************************************************************ \begin{code} -deSugar :: HscEnv -> TcGblEnv -> IO (Maybe ModGuts) +deSugar :: HscEnv -> TcGblEnv -> IO (Bag WarnMsg, Maybe ModGuts) -- Can modify PCS by faulting in more declarations deSugar hsc_env - (TcGblEnv { tcg_mod = mod, - tcg_type_env = type_env, - tcg_imports = imports, - tcg_exports = exports, - tcg_dus = dus, - tcg_inst_uses = dfun_uses_var, - tcg_rdr_env = rdr_env, - tcg_fix_env = fix_env, - tcg_deprecs = deprecs, - tcg_insts = insts, - tcg_binds = binds, - tcg_fords = fords, - tcg_rules = rules }) + tcg_env@(TcGblEnv { tcg_mod = mod, + tcg_src = hsc_src, + tcg_type_env = type_env, + tcg_imports = imports, + tcg_home_mods = home_mods, + tcg_exports = exports, + tcg_dus = dus, + tcg_inst_uses = dfun_uses_var, + tcg_th_used = th_var, + tcg_keep = keep_var, + tcg_rdr_env = rdr_env, + tcg_fix_env = fix_env, + tcg_deprecs = deprecs, + tcg_binds = binds, + tcg_fords = fords, + tcg_rules = rules, + tcg_insts = insts }) = do { showPass dflags "Desugar" - -- Do desugaring - ; let { is_boot = imp_dep_mods imports } - ; (results, warnings) <- initDs hsc_env mod type_env is_boot $ - dsProgram binds rules fords - - ; let { (ds_binds, ds_rules, ds_fords) = results - ; warns = mapBag mk_warn warnings - ; warn_doc = pprBagOfWarnings warns } - - -- Display any warnings - ; doIfSet (not (isEmptyBag warnings)) - (printErrs warn_doc) - - -- if warnings are considered errors, leave. + -- Desugar the program + ; ((all_prs, ds_rules, ds_fords), warns) + <- initDs hsc_env mod rdr_env type_env $ do + { core_prs <- dsTopLHsBinds auto_scc binds + ; (ds_fords, foreign_prs) <- dsForeigns fords + ; let all_prs = foreign_prs ++ core_prs + local_bndrs = mkVarSet (map fst all_prs) + ; ds_rules <- mappM (dsRule mod local_bndrs) rules + ; return (all_prs, catMaybes ds_rules, ds_fords) } + + -- If warnings are considered errors, leave. ; if errorsFound dflags (warns, emptyBag) - then return Nothing - else do { + then return (warns, Nothing) + else do + + { -- Add export flags to bindings + keep_alive <- readIORef keep_var + ; let final_prs = addExportFlags ghci_mode exports keep_alive + all_prs ds_rules + 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# + -- we want F# to be in scope in the foreign marshalling code! + -- You might think it doesn't matter, but the simplifier brings all top-level + -- 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 -- Dump output ; doIfSet (dopt Opt_D_dump_ds dflags) (printDump (ppr_ds_rules ds_rules)) ; dfun_uses <- readIORef dfun_uses_var -- What dfuns are used - ; let used_names = allUses dus emptyNameSet `unionNameSets` dfun_uses - ; usages <- mkUsageInfo hsc_env imports used_names + ; th_used <- readIORef th_var -- Whether TH is used + ; let used_names = allUses dus `unionNameSets` dfun_uses + thPackage = thPackageId (pkgState dflags) + pkgs | ExtPackage th_id <- thPackage, th_used + = insertList th_id (imp_dep_pkgs imports) + | otherwise + = imp_dep_pkgs imports + + dep_mods = moduleEnvElts (delModuleEnv (imp_dep_mods imports) mod) + -- M.hi-boot can be in the imp_dep_mods, but we must remove + -- it before recording the modules on which this one depends! + -- (We want to retain M.hi-boot in imp_dep_mods so that + -- loadHiBootInterface can see if M's direct imports depend + -- on M.hi-boot, and hence that we should do the hi-boot consistency + -- check.) + + dir_imp_mods = imp_mods imports + + ; usages <- mkUsageInfo hsc_env home_mods dir_imp_mods dep_mods used_names + ; let - deps = Deps { dep_mods = moduleEnvElts (imp_dep_mods imports), - dep_pkgs = imp_dep_pkgs imports, - dep_orphs = imp_orphs imports } + -- Modules don't compare lexicographically usually, + -- but we want them to do so here. + le_mod :: Module -> Module -> Bool + le_mod m1 m2 = moduleFS m1 <= moduleFS m2 + le_dep_mod :: (Module, IsBootInterface) -> (Module, IsBootInterface) -> Bool + le_dep_mod (m1,_) (m2,_) = m1 `le_mod` m2 + + deps = Deps { dep_mods = sortLe le_dep_mod dep_mods, + dep_pkgs = sortLe (<=) pkgs, + dep_orphs = sortLe le_mod (imp_orphs imports) } + -- sort to get into canonical order + mod_guts = ModGuts { mg_module = mod, + mg_boot = isHsBoot hsc_src, mg_exports = exports, mg_deps = deps, + mg_home_mods = home_mods, mg_usages = usages, - mg_dir_imps = [m | (m,_) <- moduleEnvElts (imp_mods imports)], + mg_dir_imps = [m | (m,_,_) <- moduleEnvElts dir_imp_mods], mg_rdr_env = rdr_env, mg_fix_env = fix_env, mg_deprecs = deprecs, @@ -118,37 +161,31 @@ deSugar hsc_env mg_binds = ds_binds, mg_foreign = ds_fords } - ; return (Just mod_guts) + ; return (warns, Just mod_guts) }} where dflags = hsc_dflags hsc_env - print_unqual = unQualInScope rdr_env - - -- Desugarer warnings are SDocs; here we - -- add the info about whether or not to print unqualified - mk_warn :: (SrcLoc,SDoc) -> (SrcLoc, Pretty.Doc) - mk_warn (loc, sdoc) = addShortWarnLocLine loc print_unqual sdoc - + ghci_mode = ghcMode (hsc_dflags hsc_env) + auto_scc | opt_SccProfilingOn = TopLevel + | otherwise = NoSccs deSugarExpr :: HscEnv -> Module -> GlobalRdrEnv -> TypeEnv - -> TypecheckedHsExpr + -> LHsExpr Id -> IO CoreExpr deSugarExpr hsc_env this_mod rdr_env type_env tc_expr = do { showPass dflags "Desugar" ; us <- mkSplitUniqSupply 'd' -- Do desugaring - ; let { is_boot = emptyModuleEnv } -- Assume no hi-boot files when - -- doing stuff from the command line - ; (core_expr, ds_warns) <- initDs hsc_env this_mod type_env is_boot $ - dsExpr tc_expr + ; (core_expr, ds_warns) <- initDs hsc_env this_mod rdr_env type_env $ + dsLExpr tc_expr -- Display any warnings -- Note: if -Werror is used, we don't signal an error here. ; doIfSet (not (isEmptyBag ds_warns)) - (printErrs (pprBagOfWarnings (mapBag mk_warn ds_warns))) + (printErrs (pprBagOfWarnings ds_warns)) -- Dump output ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr) @@ -157,35 +194,60 @@ deSugarExpr hsc_env this_mod rdr_env type_env tc_expr } where dflags = hsc_dflags hsc_env - print_unqual = unQualInScope rdr_env - mk_warn :: (SrcLoc,SDoc) -> (SrcLoc, Pretty.Doc) - mk_warn (loc,sdoc) = addShortWarnLocLine loc print_unqual sdoc - -dsProgram all_binds rules fo_decls - = dsMonoBinds auto_scc all_binds [] `thenDs` \ core_prs -> - dsForeigns fo_decls `thenDs` \ (ds_fords, foreign_binds) -> - let - ds_binds = [Rec (foreign_binds ++ core_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# - -- we want F# to be in scope in the foreign marshalling code! - -- You might think it doesn't matter, but the simplifier brings all top-level - -- things into the in-scope set before simplifying; so we get no unfolding for F#! - - local_binders = mkVarSet (bindersOfBinds ds_binds) - in - mappM (dsRule local_binders) rules `thenDs` \ ds_rules -> - returnDs (ds_binds, ds_rules, ds_fords) +-- addExportFlags +-- Set the no-discard flag if either +-- a) the Id is exported +-- b) it's mentioned in the RHS of an orphan rule +-- c) it's in the keep-alive set +-- +-- It means that the binding won't be discarded EVEN if the binding +-- ends up being trivial (v = w) -- the simplifier would usually just +-- substitute w for v throughout, but we don't apply the substitution to +-- the rules (maybe we should?), so this substitution would make the rule +-- bogus. + +-- You might wonder why exported Ids aren't already marked as such; +-- it's just because the type checker is rather busy already and +-- I didn't want to pass in yet another mapping. + +addExportFlags ghci_mode exports keep_alive prs rules + = [(add_export bndr, rhs) | (bndr,rhs) <- prs] where - auto_scc | opt_SccProfilingOn = TopLevel - | otherwise = NoSccs + 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 + + -- In interactive mode, we don't want to discard any top-level + -- entities at all (eg. do not inline them away during + -- simplification), and retain them all in the TypeEnv so they are + -- available from the command line. + -- + -- isExternalName separates the user-defined top-level names from those + -- introduced by the type checker. + is_exported :: Name -> Bool + is_exported | ghci_mode == Interactive = isExternalName + | otherwise = (`elemNameSet` exports) ppr_ds_rules [] = empty ppr_ds_rules rules = text "" $$ text "-------------- DESUGARED RULES -----------------" $$ - pprIdRules rules + pprRules rules \end{code} @@ -197,49 +259,37 @@ ppr_ds_rules rules %************************************************************************ \begin{code} -dsRule :: IdSet -> TypecheckedRuleDecl -> DsM (Id, CoreRule) -dsRule in_scope (HsRule name act vars lhs rhs loc) - = putSrcLocDs loc $ - ds_lhs all_vars lhs `thenDs` \ (fn, args) -> - dsExpr rhs `thenDs` \ core_rhs -> - returnDs (fn, Rule name act tpl_vars args core_rhs) - where - tpl_vars = [var | RuleBndr var <- vars] - all_vars = mkInScopeSet (in_scope `unionVarSet` mkVarSet tpl_vars) - -ds_lhs all_vars lhs - = let - (dict_binds, body) = case lhs of - (HsLet (MonoBind dict_binds _ _) body) -> (dict_binds, body) - other -> (EmptyMonoBinds, lhs) - in - ds_dict_binds dict_binds `thenDs` \ dict_binds' -> - dsExpr body `thenDs` \ body' -> - +dsRule :: Module -> IdSet -> LRuleDecl Id -> DsM (Maybe CoreRule) +dsRule mod in_scope (L loc (HsRule name act vars lhs rhs)) + = putSrcSpanDs loc $ + do { let bndrs = [var | RuleBndr (L _ var) <- vars] + ; lhs' <- dsLExpr lhs + ; rhs' <- dsLExpr rhs + + ; case decomposeRuleLhs bndrs lhs' of { + Nothing -> do { dsWarn msg; return Nothing } ; + Just (bndrs', fn_id, args) -> do + -- Substitute the dict bindings eagerly, -- and take the body apart into a (f args) form - let - subst_env = mkSubstEnv [id | (id,rhs) <- dict_binds'] - [ContEx subst_env rhs | (id,rhs) <- dict_binds'] - -- Note recursion here... substitution won't terminate - -- if there is genuine recursion... which there isn't - - subst = mkSubst all_vars subst_env - body'' = substExpr subst body' - in - - -- Now unpack the resulting body - let - pair = case collectArgs body'' of - (Var fn, args) -> (fn, args) - other -> pprPanic "dsRule" (ppr lhs) - in - returnDs pair - -ds_dict_binds EmptyMonoBinds = returnDs [] -ds_dict_binds (AndMonoBinds b1 b2) = ds_dict_binds b1 `thenDs` \ env1 -> - ds_dict_binds b2 `thenDs` \ env2 -> - returnDs (env1 ++ env2) -ds_dict_binds (VarMonoBind id rhs) = dsExpr rhs `thenDs` \ rhs' -> - returnDs [(id,rhs')] + { let local_rule = nameIsLocalOrFrom mod fn_name + -- NB we can't use isLocalId in the orphan test, + -- because isLocalId isn't true of class methods + fn_name = idName fn_id + lhs_names = fn_name : nameSetToList (exprsFreeNames args) + -- No need to delete bndrs, because + -- exprsFreeNames finds only External names + orph = case filter (nameIsLocalOrFrom mod) lhs_names of + (n:ns) -> Just (nameOccName n) + [] -> Nothing + + 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, ru_orph = orph } + ; return (Just rule) + } } } + where + msg = hang (ptext SLIT("RULE left-hand side too complicated to desugar; ignored")) + 2 (ppr lhs) \end{code}