2 % (c) The GRASP Project, Glasgow University, 1992-1998
4 \section[Rename]{Renaming and dependency analysis passes}
7 module Rename ( renameModule ) where
9 #include "HsVersions.h"
12 import RdrHsSyn ( RdrNameHsModule )
13 import RnHsSyn ( RenamedHsModule, RenamedHsDecl,
14 extractHsTyNames, extractHsCtxtTyNames
17 import CmdLineOpts ( opt_HiMap, opt_D_dump_rn_trace,
18 opt_D_dump_rn, opt_D_dump_rn_stats,
19 opt_WarnUnusedBinds, opt_WarnUnusedImports
22 import RnNames ( getGlobalNames )
23 import RnSource ( rnSourceDecls, rnDecl )
24 import RnIfaces ( getImportedInstDecls, importDecl, getImportVersions,
25 getImportedRules, loadHomeInterface, getSlurped
27 import RnEnv ( availName, availNames, availsToNameSet,
28 warnUnusedTopNames, mapFvRn,
29 FreeVars, plusFVs, plusFV, unitFV, emptyFVs, isEmptyFVs
31 import Module ( Module, ModuleName, pprModule, mkSearchPath, mkThisModule )
32 import Name ( Name, isLocallyDefined,
33 NamedThing(..), ImportReason(..), Provenance(..),
34 pprOccName, getNameProvenance,
35 maybeWiredInTyConName, maybeWiredInIdName, isWiredInName
38 import DataCon ( dataConTyCon, dataConType )
39 import TyCon ( TyCon, tyConDataCons, isSynTyCon, getSynTyConDefn )
40 import RdrName ( RdrName )
42 import PrelMods ( mAIN_Name, pREL_MAIN_Name )
43 import TysWiredIn ( unitTyCon, intTyCon, doubleTyCon, boolTyCon )
44 import PrelInfo ( ioTyCon_NAME, thinAirIdNames )
45 import Type ( namesOfType, funTyCon )
46 import ErrUtils ( pprBagOfErrors, pprBagOfWarnings,
47 doIfSet, dumpIfSet, ghcExit
49 import BasicTypes ( NewOrData(..) )
50 import Bag ( isEmptyBag, bagToList )
51 import FiniteMap ( fmToList, delListFromFM, addToFM, sizeFM, eltsFM )
52 import UniqSupply ( UniqSupply )
53 import Util ( equivClasses )
54 import Maybes ( maybeToBool )
61 renameModule :: UniqSupply
65 , RenamedHsModule -- Output, after renaming
66 , InterfaceDetails -- Interface; for interface file generation
67 , RnNameSupply -- Final env; for renaming derivings
68 , [ModuleName] -- Imported modules; for profiling
71 renameModule us this_mod@(HsModule mod_name vers exports imports local_decls loc)
72 = -- Initialise the renamer monad
73 initRn mod_name us (mkSearchPath opt_HiMap) loc
75 \ (maybe_rn_stuff, rn_errs_bag, rn_warns_bag) ->
78 doIfSet (not (isEmptyBag rn_warns_bag))
79 (printErrs (pprBagOfWarnings rn_warns_bag)) >>
81 -- Check for errors; exit if so
82 doIfSet (not (isEmptyBag rn_errs_bag))
83 (printErrs (pprBagOfErrors rn_errs_bag) >>
87 -- Dump output, if any
88 (case maybe_rn_stuff of
90 Just results@(_, rn_mod, _, _, _)
91 -> dumpIfSet opt_D_dump_rn "Renamer:"
101 rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
102 = -- FIND THE GLOBAL NAME ENVIRONMENT
103 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
105 -- CHECK FOR EARLY EXIT
106 if not (maybeToBool maybe_stuff) then
107 -- Everything is up to date; no need to recompile further
112 Just (export_env, gbl_env, fixity_env, global_avail_env) = maybe_stuff
116 initRnMS gbl_env fixity_env SourceMode (
117 rnSourceDecls local_decls
118 ) `thenRn` \ (rn_local_decls, source_fvs) ->
120 -- SLURP IN ALL THE NEEDED DECLARATIONS
122 real_source_fvs = implicitFVs mod_name `plusFV` source_fvs
123 -- It's important to do the "plus" this way round, so that
124 -- when compiling the prelude, locally-defined (), Bool, etc
125 -- override the implicit ones.
127 slurpImpDecls real_source_fvs `thenRn` \ rn_imp_decls ->
129 -- EXIT IF ERRORS FOUND
130 checkErrsRn `thenRn` \ no_errs_so_far ->
131 if not no_errs_so_far then
132 -- Found errors already, so exit now
137 -- GENERATE THE VERSION/USAGE INFO
138 getImportVersions mod_name exports `thenRn` \ my_usages ->
139 getNameSupplyRn `thenRn` \ name_supply ->
141 -- REPORT UNUSED NAMES
142 reportUnusedNames gbl_env global_avail_env
146 -- RETURN THE RENAMED MODULE
148 has_orphans = any isOrphanDecl rn_local_decls
149 direct_import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
150 rn_all_decls = rn_imp_decls ++ rn_local_decls
151 renamed_module = HsModule mod_name vers
152 trashed_exports trashed_imports
156 rnStats rn_imp_decls `thenRn_`
157 returnRn (Just (mkThisModule mod_name,
159 (has_orphans, my_usages, export_env),
163 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
164 trashed_imports = {-trace "rnSource:trashed_imports"-} []
167 @implicitFVs@ forces the renamer to slurp in some things which aren't
168 mentioned explicitly, but which might be needed by the type checker.
172 = implicit_main `plusFV`
173 mkNameSet default_tys `plusFV`
174 mkNameSet thinAirIdNames
176 -- Add occurrences for Int, Double, and (), because they
177 -- are the types to which ambigious type variables may be defaulted by
178 -- the type checker; so they won't always appear explicitly.
179 -- [The () one is a GHC extension for defaulting CCall results.]
180 -- ALSO: funTyCon, since it occurs implicitly everywhere!
181 -- (we don't want to be bothered with making funTyCon a
182 -- free var at every function application!)
183 default_tys = [getName intTyCon, getName doubleTyCon,
184 getName unitTyCon, getName funTyCon, getName boolTyCon]
186 -- Add occurrences for IO or PrimIO
187 implicit_main | mod_name == mAIN_Name
188 || mod_name == pREL_MAIN_Name = unitFV ioTyCon_NAME
189 | otherwise = emptyFVs
193 isOrphanDecl (InstD (InstDecl inst_ty _ _ _ _))
194 = not (foldNameSet ((||) . isLocallyDefined) False (extractHsTyNames inst_ty))
195 isOrphanDecl (RuleD (RuleDecl _ _ _ lhs _ _))
198 check (HsVar v) = not (isLocallyDefined v)
199 check (HsApp f a) = check f && check a
201 isOrphanDecl other = False
205 %*********************************************************
207 \subsection{Slurping declarations}
209 %*********************************************************
212 -------------------------------------------------------
213 slurpImpDecls source_fvs
214 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
216 -- The current slurped-set records all local things
217 getSlurped `thenRn` \ source_binders ->
218 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls1, needed1, inst_gates) ->
220 -- Now we can get the instance decls
221 slurpInstDecls decls1 needed1 inst_gates `thenRn` \ (decls2, needed2) ->
223 -- And finally get everything else
224 closeDecls decls2 needed2
226 -------------------------------------------------------
227 slurpSourceRefs :: NameSet -- Variables defined in source
228 -> FreeVars -- Variables referenced in source
229 -> RnMG ([RenamedHsDecl],
230 FreeVars, -- Un-satisfied needs
232 -- The declaration (and hence home module) of each gate has
233 -- already been loaded
235 slurpSourceRefs source_binders source_fvs
236 = go [] -- Accumulating decls
237 emptyFVs -- Unsatisfied needs
238 source_fvs -- Accumulating gates
239 (nameSetToList source_fvs) -- Gates whose defn hasn't been loaded yet
241 go decls fvs gates []
242 = returnRn (decls, fvs, gates)
244 go decls fvs gates (wanted_name:refs)
245 | isWiredInName wanted_name
246 = load_home wanted_name `thenRn_`
247 go decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
250 = importDecl wanted_name `thenRn` \ maybe_decl ->
252 -- No declaration... (already slurped, or local)
253 Nothing -> go decls fvs gates refs
254 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
256 new_gates = getGates source_fvs new_decl
258 go (new_decl : decls)
260 (gates `plusFV` new_gates)
261 (nameSetToList new_gates ++ refs)
263 -- When we find a wired-in name we must load its
264 -- home module so that we find any instance decls therein
266 | name `elemNameSet` source_binders = returnRn ()
267 -- When compiling the prelude, a wired-in thing may
268 -- be defined in this module, in which case we don't
269 -- want to load its home module!
270 -- Using 'isLocallyDefined' doesn't work because some of
271 -- the free variables returned are simply 'listTyCon_Name',
272 -- with a system provenance. We could look them up every time
273 -- but that seems a waste.
274 | otherwise = loadHomeInterface doc name `thenRn_`
277 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
280 @slurpInstDecls@ imports appropriate instance decls.
281 It has to incorporate a loop, because consider
283 instance Foo a => Baz (Maybe a) where ...
285 It may be that @Baz@ and @Maybe@ are used in the source module,
286 but not @Foo@; so we need to chase @Foo@ too.
289 slurpInstDecls decls needed gates
291 = returnRn (decls, needed)
294 = getImportedInstDecls gates `thenRn` \ inst_decls ->
295 rnInstDecls decls needed emptyFVs inst_decls `thenRn` \ (decls1, needed1, gates1) ->
296 slurpInstDecls decls1 needed1 gates1
298 rnInstDecls decls fvs gates []
299 = returnRn (decls, fvs, gates)
300 rnInstDecls decls fvs gates (d:ds)
301 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
302 rnInstDecls (new_decl:decls)
304 (gates `plusFV` getInstDeclGates new_decl)
308 -------------------------------------------------------
309 -- closeDecls keeps going until the free-var set is empty
310 closeDecls decls needed
311 | not (isEmptyFVs needed)
312 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
313 closeDecls decls1 needed1
316 = getImportedRules `thenRn` \ rule_decls ->
318 [] -> returnRn decls -- No new rules, so we are done
319 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
320 closeDecls decls1 needed1
323 -------------------------------------------------------
324 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
325 -> [(Module, RdrNameHsDecl)]
326 -> RnM d ([RenamedHsDecl], FreeVars)
327 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
328 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
329 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
331 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
334 -------------------------------------------------------
335 -- Augment decls with any decls needed by needed.
336 -- Return also free vars of the new decls (only)
337 slurpDecls decls needed
338 = go decls emptyFVs (nameSetToList needed)
340 go decls fvs [] = returnRn (decls, fvs)
341 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
344 -------------------------------------------------------
345 slurpDecl decls fvs wanted_name
346 = importDecl wanted_name `thenRn` \ maybe_decl ->
348 -- No declaration... (wired in thing)
349 Nothing -> returnRn (decls, fvs)
351 -- Found a declaration... rename it
352 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
353 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
357 %*********************************************************
359 \subsection{Extracting the `gates'}
361 %*********************************************************
363 When we import a declaration like
365 data T = T1 Wibble | T2 Wobble
367 we don't want to treat @Wibble@ and @Wobble@ as gates
368 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
369 If only @T@ is mentioned
370 we want only @T@ to be a gate;
371 that way we don't suck in useless instance
372 decls for (say) @Eq Wibble@, when they can't possibly be useful.
374 @getGates@ takes a newly imported (and renamed) decl, and the free
375 vars of the source program, and extracts from the decl the gate names.
378 getGates source_fvs (SigD (IfaceSig _ ty _ _))
379 = extractHsTyNames ty
381 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs sigs _ _ _ _ _ _))
382 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
383 (map getTyVarName tvs)
384 `addOneToNameSet` cls
386 get (ClassOpSig n _ ty _)
387 | n `elemNameSet` source_fvs = extractHsTyNames ty
388 | otherwise = emptyFVs
390 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
391 = delListFromNameSet (extractHsTyNames ty)
392 (map getTyVarName tvs)
393 -- A type synonym type constructor isn't a "gate" for instance decls
395 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
396 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
397 (map getTyVarName tvs)
398 `addOneToNameSet` tycon
400 get (ConDecl n tvs ctxt details _)
401 | n `elemNameSet` source_fvs
402 -- If the constructor is method, get fvs from all its fields
403 = delListFromNameSet (get_details details `plusFV`
404 extractHsCtxtTyNames ctxt)
405 (map getTyVarName tvs)
406 get (ConDecl n tvs ctxt (RecCon fields) _)
407 -- Even if the constructor isn't mentioned, the fields
408 -- might be, as selectors. They can't mention existentially
409 -- bound tyvars (typechecker checks for that) so no need for
410 -- the deleteListFromNameSet part
411 = foldr (plusFV . get_field) emptyFVs fields
413 get other_con = emptyFVs
415 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
416 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
417 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
418 get_details (NewCon t _) = extractHsTyNames t
420 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
421 | otherwise = emptyFVs
423 get_bang (Banged t) = extractHsTyNames t
424 get_bang (Unbanged t) = extractHsTyNames t
425 get_bang (Unpacked t) = extractHsTyNames t
427 getGates source_fvs other_decl = emptyFVs
430 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
431 rather than a declaration.
434 getWiredInGates :: Name -> FreeVars
435 getWiredInGates name -- No classes are wired in
436 | is_id = getWiredInGates_s (namesOfType (idType the_id))
437 | isSynTyCon the_tycon = getWiredInGates_s
438 (delListFromNameSet (namesOfType ty) (map getName tyvars))
439 | otherwise = unitFV name
441 maybe_wired_in_id = maybeWiredInIdName name
442 is_id = maybeToBool maybe_wired_in_id
443 maybe_wired_in_tycon = maybeWiredInTyConName name
444 Just the_id = maybe_wired_in_id
445 Just the_tycon = maybe_wired_in_tycon
446 (tyvars,ty) = getSynTyConDefn the_tycon
448 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
452 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
453 getInstDeclGates other = emptyFVs
457 %*********************************************************
459 \subsection{Unused names}
461 %*********************************************************
464 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _) mentioned_names
465 | not (opt_WarnUnusedBinds || opt_WarnUnusedImports)
470 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
472 -- Now, a use of C implies a use of T,
473 -- if C was brought into scope by T(..) or T(C)
474 really_used_names = used_names `unionNameSets`
475 mkNameSet [ availName avail
476 | sub_name <- nameSetToList used_names,
477 let avail = case lookupNameEnv avail_env sub_name of
479 Nothing -> pprTrace "r.u.n" (ppr sub_name) $
483 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
484 defined_but_not_used =
485 nameSetToList (defined_names `minusNameSet` really_used_names)
487 -- Filter out the ones only defined implicitly
488 bad_guys = filter reportableUnusedName defined_but_not_used
490 warnUnusedTopNames bad_guys `thenRn_`
493 reportableUnusedName :: Name -> Bool
494 reportableUnusedName name
495 = explicitlyImported (getNameProvenance name)
497 explicitlyImported (LocalDef _ _) = True
498 -- Report unused defns of local vars
499 explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl
500 -- Report unused explicit imports
501 explicitlyImported other = False
502 -- Don't report others
504 rnStats :: [RenamedHsDecl] -> RnMG ()
506 | opt_D_dump_rn_trace ||
507 opt_D_dump_rn_stats ||
509 = getRnStats imp_decls `thenRn` \ msg ->
510 ioToRnM (printErrs msg) `thenRn_`
513 | otherwise = returnRn ()
518 %*********************************************************
520 \subsection{Statistics}
522 %*********************************************************
525 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
526 getRnStats imported_decls
527 = getIfacesRn `thenRn` \ ifaces ->
529 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
531 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
532 -- Data, newtype, and class decls are in the decls_fm
533 -- under multiple names; the tycon/class, and each
534 -- constructor/class op too.
535 -- The 'True' selects just the 'main' decl
536 not (isLocallyDefined (availName avail))
539 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
540 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
542 unslurped_insts = iInsts ifaces
543 inst_decls_unslurped = length (bagToList unslurped_insts)
544 inst_decls_read = id_sp + inst_decls_unslurped
547 [int n_mods <+> text "interfaces read",
548 hsep [ int cd_sp, text "class decls imported, out of",
549 int cd_rd, text "read"],
550 hsep [ int dd_sp, text "data decls imported, out of",
551 int dd_rd, text "read"],
552 hsep [ int nd_sp, text "newtype decls imported, out of",
553 int nd_rd, text "read"],
554 hsep [int sd_sp, text "type synonym decls imported, out of",
555 int sd_rd, text "read"],
556 hsep [int vd_sp, text "value signatures imported, out of",
557 int vd_rd, text "read"],
558 hsep [int id_sp, text "instance decls imported, out of",
559 int inst_decls_read, text "read"],
560 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
561 [d | TyClD d <- imported_decls, isClassDecl d]),
562 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
563 [d | TyClD d <- decls_read, isClassDecl d])]
565 returnRn (hcat [text "Renamer stats: ", stats])
575 tycl_decls = [d | TyClD d <- decls]
576 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
578 val_decls = length [() | SigD _ <- decls]
579 inst_decls = length [() | InstD _ <- decls]