-deSugar :: UniqSupply -- name supply
- -> FAST_STRING -- module name
-
- -> (TypecheckedHsBinds, -- input: recsel, class, instance, and value
- TypecheckedHsBinds, -- bindings; see "tcModule" (which produces
- TypecheckedHsBinds, -- them)
- TypecheckedHsBinds,
- TypecheckedHsBinds)
--- ToDo: handling of const_inst thingies is certainly WRONG ***************************
-
- -> ([CoreBinding], -- output
- DsWarnings) -- Shadowing complaints
-
-deSugar us mod_name (recsel_binds, clas_binds, inst_binds, val_binds, const_inst_binds)
- = let
- (us0, us0a) = splitUniqSupply us
- (us1, us1a) = splitUniqSupply us0a
- (us2, us2a) = splitUniqSupply us1a
- (us3, us3a) = splitUniqSupply us2a
- (us4, us5) = splitUniqSupply us3a
-
-
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
-
- (core_const_binds, shadows1)
- = initDs us0 nullIdEnv mod_name (dsBinds const_inst_binds)
- core_const_prs = pairsFromCoreBinds core_const_binds
-
- (core_clas_binds, shadows2)
- = initDs us1 nullIdEnv mod_name (dsBinds clas_binds)
- core_clas_prs = pairsFromCoreBinds core_clas_binds
-
- (core_inst_binds, shadows3)
- = initDs us2 nullIdEnv mod_name (dsBinds inst_binds)
- core_inst_prs = pairsFromCoreBinds core_inst_binds
-
- (core_val_binds, shadows4)
- = initDs us3 nullIdEnv mod_name (dsBinds val_binds)
- core_val_pairs = map (addAutoScc module_and_group) (pairsFromCoreBinds core_val_binds)
-
- (core_recsel_binds, shadows5)
- = initDs us4 nullIdEnv mod_name (dsBinds recsel_binds)
- core_recsel_prs = pairsFromCoreBinds core_recsel_binds
-
- final_binds
- = if (null core_clas_prs && null core_inst_prs
- && null core_recsel_prs {-???dont know???-} && null core_const_prs) then
- -- we don't have to make the whole thing recursive
- core_clas_binds ++ core_val_binds
-
- else -- gotta make it recursive (sigh)
- [Rec (core_clas_prs ++ core_inst_prs
- ++ core_const_prs ++ core_val_pairs ++ core_recsel_prs)]
-
- lift_final_binds = liftCoreBindings us5 final_binds
-
- really_final_binds = if opt_DoCoreLinting
- then lintCoreBindings PprDebug "Desugarer" False lift_final_binds
- else lift_final_binds
-
- shadows = shadows1 `unionBags` shadows2 `unionBags`
- shadows3 `unionBags` shadows4 `unionBags` shadows5
- in
- (really_final_binds, shadows)
+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_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"
+
+ -- Desugar the program
+ ; ((all_prs, ds_rules, ds_fords), warns)
+ <- case ghcMode (hsc_dflags hsc_env) of
+ JustTypecheck -> return (([], [], NoStubs), emptyBag)
+ _ -> 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 (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 | 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
+ -- 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 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 = ghcMode (hsc_dflags 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
+ ; (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))
+ (printBagOfWarnings dflags 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.
+
+addExportFlags ghci_mode exports keep_alive prs rules
+ = [(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
+
+ -- 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 "" $$ text "-------------- DESUGARED RULES -----------------" $$
+ pprRules rules