X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDesugar.lhs;h=39f3978d02b84c11aaccf5b82f96c69f6a6c265e;hb=ef5b4b146aa172d8ac10f39b5eb3d7a0f948d8f1;hp=2cb65c9c53b84ef96ac13c54aa18d67329ffa6bb;hpb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/Desugar.lhs b/ghc/compiler/deSugar/Desugar.lhs index 2cb65c9..39f3978 100644 --- a/ghc/compiler/deSugar/Desugar.lhs +++ b/ghc/compiler/deSugar/Desugar.lhs @@ -4,67 +4,303 @@ \section[Desugar]{@deSugar@: the main function} \begin{code} -module Desugar ( deSugar ) where +module Desugar ( deSugar, deSugarExpr ) where #include "HsVersions.h" -import CmdLineOpts ( opt_D_dump_ds ) -import HsSyn ( MonoBinds ) -import TcHsSyn ( TypecheckedMonoBinds, TypecheckedForeignDecl ) +import CmdLineOpts ( DynFlag(..), DynFlags(..), dopt, opt_SccProfilingOn ) +import HscTypes ( ModGuts(..), ModGuts, HscEnv(..), GhciMode(..), + Dependencies(..), TypeEnv, IsBootInterface, unQualInScope ) +import HsSyn ( RuleDecl(..), RuleBndr(..), HsExpr(..), LHsExpr, + HsBindGroup(..), LRuleDecl, HsBind(..) ) +import TcRnTypes ( TcGblEnv(..), ImportAvails(..) ) +import MkIface ( mkUsageInfo ) +import Id ( Id, setIdLocalExported, idName, idIsFrom, isLocalId ) +import Name ( Name, isExternalName ) import CoreSyn +import PprCore ( pprIdRules, pprCoreExpr ) +import Subst ( SubstResult(..), substExpr, mkSubst, extendIdSubstList ) import DsMonad -import DsBinds ( dsMonoBinds ) +import DsExpr ( dsLExpr ) +import DsBinds ( dsHsBinds, AutoScc(..) ) import DsForeign ( dsForeigns ) -import DsUtils import DsExpr () -- Forces DsExpr to be compiled; DsBinds only -- depends on DsExpr.hi-boot. - -import Bag ( isEmptyBag ) -import BasicTypes ( Module ) -import CmdLineOpts ( opt_SccGroup, opt_SccProfilingOn ) -import CoreLint ( beginPass, endPass ) -import ErrUtils ( doIfSet ) +import Module ( Module, moduleEnvElts, delModuleEnv, moduleFS ) +import Id ( Id ) +import RdrName ( GlobalRdrEnv ) +import NameSet +import VarEnv +import VarSet +import Bag ( Bag, isEmptyBag, mapBag, emptyBag, bagToList ) +import CoreLint ( showPass, endPass ) +import CoreFVs ( ruleRhsFreeVars ) +import Packages ( PackageState(thPackageId) ) +import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings, + mkWarnMsg, errorsFound, WarnMsg ) +import ListSetOps ( insertList ) import Outputable -import UniqSupply ( splitUniqSupply, UniqSupply ) +import UniqSupply ( mkSplitUniqSupply ) +import SrcLoc ( Located(..), SrcSpan, unLoc ) +import DATA_IOREF ( readIORef ) +import FastString +import Util ( sortLe ) \end{code} -The only trick here is to get the @DsMonad@ stuff off to a good -start. +%************************************************************************ +%* * +%* The main function: deSugar +%* * +%************************************************************************ \begin{code} -deSugar :: UniqSupply -- name supply - -> GlobalValueEnv -- value env - -> Module -- module name - -> TypecheckedMonoBinds - -> [TypecheckedForeignDecl] - -> IO ([CoreBind], SDoc, SDoc) -- output - -deSugar us global_val_env mod_name all_binds fo_decls = do - beginPass "Desugar" +deSugar :: HscEnv -> TcGblEnv -> IO (Bag WarnMsg, Maybe ModGuts) +-- Can modify PCS by faulting in more declarations + +deSugar hsc_env + tcg_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_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" + + -- Desugar the program + ; ((all_prs, ds_rules, ds_fords), warns) + <- initDs hsc_env mod rdr_env type_env $ do + { core_prs <- dsHsBinds 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, ds_rules, ds_fords) } + + + + -- If warnings are considered errors, leave. + ; if errorsFound dflags (warns, emptyBag) + 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 + + -- 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 + ; th_used <- readIORef th_var -- Whether TH is used + ; let used_names = allUses dus `unionNameSets` dfun_uses + thPackage = thPackageId (pkgState dflags) + pkgs | Just 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 dir_imp_mods dep_mods used_names + + ; let + -- 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_exports = exports, + mg_deps = deps, + mg_usages = usages, + mg_dir_imps = [m | (m,_,_) <- moduleEnvElts dir_imp_mods], + mg_rdr_env = rdr_env, + mg_fix_env = fix_env, + mg_deprecs = deprecs, + mg_types = type_env, + mg_insts = insts, + mg_rules = ds_rules, + mg_binds = ds_binds, + mg_foreign = ds_fords } + + ; return (warns, Just mod_guts) + }} + + where + dflags = hsc_dflags hsc_env + ghci_mode = hsc_mode hsc_env + auto_scc | opt_SccProfilingOn = TopLevel + | otherwise = NoSccs + +deSugarExpr :: HscEnv + -> Module -> GlobalRdrEnv -> TypeEnv + -> 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 (core_prs, ds_warns) = initDs us1 global_val_env module_and_group - (dsMonoBinds opt_SccProfilingOn all_binds []) - ds_binds' = [Rec core_prs] + ; (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 ds_warns)) + + -- Dump output + ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr) + + ; return core_expr + } + where + dflags = hsc_dflags hsc_env + + +-- 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. - ((fi_binds, fe_binds, h_code, c_code), ds_warns2) = - initDs us3 global_val_env module_and_group (dsForeigns fo_decls) +addExportFlags ghci_mode exports keep_alive prs rules + = [(add_export bndr, rhs) | (bndr,rhs) <- prs] + where + add_export bndr + | isLocalId bndr && dont_discard bndr = setIdLocalExported bndr + -- The isLocalId check is to avoid fiddling with + -- locally-defined Ids like data cons and class ops + -- which are "born" as GlobalIds + | otherwise = bndr + + orph_rhs_fvs = unionVarSets [ ruleRhsFreeVars rule + | IdCoreRule _ is_orphan_rule rule <- rules, + is_orphan_rule ] + -- An orphan rule keeps alive the free vars of its right-hand side. + -- Non-orphan 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 - ds_binds = fi_binds ++ ds_binds' ++ fe_binds + -- 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 +\end{code} - -- Display any warnings - doIfSet (not (isEmptyBag ds_warns)) - (printErrs (pprDsWarnings ds_warns)) - -- Lint result if necessary - endPass "Desugar" opt_D_dump_ds ds_binds - return (ds_binds, h_code, c_code) + +%************************************************************************ +%* * +%* Desugaring transformation rules +%* * +%************************************************************************ + +\begin{code} +dsRule :: Module -> IdSet -> LRuleDecl Id -> DsM IdCoreRule +dsRule mod in_scope (L loc (HsRule name act vars lhs rhs)) + = putSrcSpanDs loc $ + ds_lhs all_vars lhs `thenDs` \ (fn, args) -> + dsLExpr rhs `thenDs` \ core_rhs -> + returnDs (IdCoreRule fn (is_orphan fn) (Rule name act tpl_vars args core_rhs)) where - (us1, us2) = splitUniqSupply us - (us3, us4) = splitUniqSupply us2 + tpl_vars = [var | RuleBndr (L _ var) <- vars] + all_vars = mkInScopeSet (extendVarSetList in_scope tpl_vars) + is_orphan id = not (idIsFrom mod id) + -- NB we can't use isLocalId in the orphan test, + -- because isLocalId isn't true of class methods + +ds_lhs all_vars lhs + = let + (dict_binds, body) = + case unLoc lhs of + (HsLet [HsBindGroup dict_binds _ _] body) -> (dict_binds, body) + other -> (emptyBag, lhs) + in + mappM ds_dict_bind (bagToList dict_binds) `thenDs` \ dict_binds' -> + dsLExpr body `thenDs` \ body' -> - module_and_group = (mod_name, grp_name) - grp_name = case opt_SccGroup of - Just xx -> _PK_ xx - Nothing -> mod_name -- default: module name + -- Substitute the dict bindings eagerly, + -- and take the body apart into a (f args) form + let + subst = extendIdSubstList (mkSubst all_vars) pairs + pairs = [(id, ContEx subst rhs) | (id,rhs) <- dict_binds'] + -- Note recursion here... substitution won't terminate + -- if there is genuine recursion... which there isn't + 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_bind (L _ (VarBind id rhs)) = + dsLExpr rhs `thenDs` \ rhs' -> + returnDs (id,rhs') \end{code}