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, removeContext
27 import RnEnv ( availName, availNames, availsToNameSet,
28 warnUnusedImports, warnUnusedLocalBinds, mapFvRn, lookupImplicitOccRn,
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, nameOccName, nameUnique,
35 getNameProvenance, isUserImportedExplicitlyName,
36 maybeWiredInTyConName, maybeWiredInIdName, isWiredInName
39 import DataCon ( dataConTyCon, dataConType )
40 import TyCon ( TyCon, tyConDataCons, isSynTyCon, getSynTyConDefn )
41 import RdrName ( RdrName )
43 import PrelMods ( mAIN_Name, pREL_MAIN_Name )
44 import TysWiredIn ( unitTyCon, intTyCon, doubleTyCon, boolTyCon )
45 import PrelInfo ( ioTyCon_NAME, thinAirIdNames, fractionalClassKeys, derivingOccurrences )
46 import Type ( namesOfType, funTyCon )
47 import ErrUtils ( printErrorsAndWarnings, dumpIfSet, ghcExit )
48 import BasicTypes ( NewOrData(..) )
49 import Bag ( isEmptyBag, bagToList )
50 import FiniteMap ( fmToList, delListFromFM, addToFM, sizeFM, eltsFM )
51 import UniqSupply ( UniqSupply )
52 import UniqFM ( lookupUFM )
53 import Util ( equivClasses )
54 import Maybes ( maybeToBool )
55 import SrcLoc ( mkBuiltinSrcLoc )
62 renameModule :: UniqSupply
66 , RenamedHsModule -- Output, after renaming
67 , InterfaceDetails -- Interface; for interface file generation
68 , RnNameSupply -- Final env; for renaming derivings
69 , [ModuleName] -- Imported modules; for profiling
72 renameModule us this_mod@(HsModule mod_name vers exports imports local_decls _ loc)
73 = -- Initialise the renamer monad
74 initRn mod_name us (mkSearchPath opt_HiMap) loc
76 \ ((maybe_rn_stuff, dump_action), rn_errs_bag, rn_warns_bag) ->
79 printErrorsAndWarnings rn_errs_bag rn_warns_bag >>
81 -- Dump any debugging output
85 if not (isEmptyBag rn_errs_bag) then
86 ghcExit 1 >> return Nothing
93 rename this_mod@(HsModule mod_name vers _ imports local_decls _ loc)
94 = -- FIND THE GLOBAL NAME ENVIRONMENT
95 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
97 -- CHECK FOR EARLY EXIT
98 if not (maybeToBool maybe_stuff) then
99 -- Everything is up to date; no need to recompile further
100 rnDump [] [] `thenRn` \ dump_action ->
101 returnRn (Nothing, dump_action)
104 Just (export_env, gbl_env, fixity_env, global_avail_env) = maybe_stuff
108 initRnMS gbl_env fixity_env SourceMode (
109 rnSourceDecls local_decls
110 ) `thenRn` \ (rn_local_decls, source_fvs) ->
112 -- SLURP IN ALL THE NEEDED DECLARATIONS
113 implicitFVs mod_name rn_local_decls `thenRn` \ implicit_fvs ->
115 real_source_fvs = implicit_fvs `plusFV` source_fvs
116 -- It's important to do the "plus" this way round, so that
117 -- when compiling the prelude, locally-defined (), Bool, etc
118 -- override the implicit ones.
120 slurpImpDecls real_source_fvs `thenRn` \ rn_imp_decls ->
122 rn_all_decls = rn_local_decls ++ rn_imp_decls
125 -- EXIT IF ERRORS FOUND
126 checkErrsRn `thenRn` \ no_errs_so_far ->
127 if not no_errs_so_far then
128 -- Found errors already, so exit now
129 rnDump rn_imp_decls rn_all_decls `thenRn` \ dump_action ->
130 returnRn (Nothing, dump_action)
133 -- GENERATE THE VERSION/USAGE INFO
134 getImportVersions mod_name export_env `thenRn` \ my_usages ->
135 getNameSupplyRn `thenRn` \ name_supply ->
137 -- REPORT UNUSED NAMES
138 reportUnusedNames gbl_env global_avail_env
142 -- RETURN THE RENAMED MODULE
144 has_orphans = any isOrphanDecl rn_local_decls
145 direct_import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
146 renamed_module = HsModule mod_name vers
147 trashed_exports trashed_imports
152 rnDump rn_imp_decls rn_all_decls `thenRn` \ dump_action ->
153 returnRn (Just (mkThisModule mod_name,
155 (has_orphans, my_usages, export_env),
157 direct_import_mods), dump_action)
159 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
160 trashed_imports = {-trace "rnSource:trashed_imports"-} []
163 @implicitFVs@ forces the renamer to slurp in some things which aren't
164 mentioned explicitly, but which might be needed by the type checker.
167 implicitFVs mod_name decls
168 = mapRn lookupImplicitOccRn implicit_occs `thenRn` \ implicit_names ->
169 returnRn (implicit_main `plusFV`
170 mkNameSet (map getName default_tycons) `plusFV`
171 mkNameSet thinAirIdNames `plusFV`
172 mkNameSet implicit_names)
174 -- Add occurrences for Int, and (), because they
175 -- are the types to which ambigious type variables may be defaulted by
176 -- the type checker; so they won't always appear explicitly.
177 -- [The () one is a GHC extension for defaulting CCall results.]
178 -- ALSO: funTyCon, since it occurs implicitly everywhere!
179 -- (we don't want to be bothered with making funTyCon a
180 -- free var at every function application!)
181 -- Double is dealt with separately in getGates
182 default_tycons = [unitTyCon, funTyCon, boolTyCon, intTyCon]
184 -- Add occurrences for IO or PrimIO
185 implicit_main | mod_name == mAIN_Name
186 || mod_name == pREL_MAIN_Name = unitFV ioTyCon_NAME
187 | otherwise = emptyFVs
189 -- Now add extra "occurrences" for things that
190 -- the deriving mechanism, or defaulting, will later need in order to
192 implicit_occs = foldr ((++) . get) [] decls
194 get (TyClD (TyData _ _ _ _ _ (Just deriv_classes) _ _))
195 = concat (map get_deriv deriv_classes)
198 get_deriv cls = case lookupUFM derivingOccurrences cls of
204 isOrphanDecl (InstD (InstDecl inst_ty _ _ _ _))
205 = not (foldNameSet ((||) . isLocallyDefined) False (extractHsTyNames (removeContext inst_ty)))
206 -- The 'removeContext' is because of
207 -- instance Foo a => Baz T where ...
208 -- The decl is an orphan if Baz and T are both not locally defined,
209 -- even if Foo *is* locally defined
211 isOrphanDecl (RuleD (RuleDecl _ _ _ lhs _ _))
214 -- At the moment we just check for common LHS forms
215 -- Expand as necessary. Getting it wrong just means
216 -- more orphans than necessary
217 check (HsVar v) = not (isLocallyDefined v)
218 check (HsApp f a) = check f && check a
219 check (HsLit _) = False
220 check (OpApp l o _ r) = check l && check o && check r
221 check (NegApp e _) = check e
222 check (HsPar e) = check e
223 check (SectionL e o) = check e && check o
224 check (SectionR o e) = check e && check o
226 check other = True -- Safe fall through
228 isOrphanDecl other = False
233 dupDefaultDeclErrRn (DefaultDecl _ locn1 : dup_things)
234 = pushSrcLocRn locn1 $
237 msg = hang (ptext SLIT("Multiple default declarations"))
238 4 (vcat (map pp dup_things))
239 pp (DefaultDecl _ locn) = ptext SLIT("here was another default declaration") <+> ppr locn
243 %*********************************************************
245 \subsection{Slurping declarations}
247 %*********************************************************
250 -------------------------------------------------------
251 slurpImpDecls source_fvs
252 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
254 -- The current slurped-set records all local things
255 getSlurped `thenRn` \ source_binders ->
256 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
258 -- And finally get everything else
259 closeDecls decls needed
261 -------------------------------------------------------
262 slurpSourceRefs :: NameSet -- Variables defined in source
263 -> FreeVars -- Variables referenced in source
264 -> RnMG ([RenamedHsDecl],
265 FreeVars) -- Un-satisfied needs
266 -- The declaration (and hence home module) of each gate has
267 -- already been loaded
269 slurpSourceRefs source_binders source_fvs
270 = go_outer [] -- Accumulating decls
271 emptyFVs -- Unsatisfied needs
272 emptyFVs -- Accumulating gates
273 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
275 -- The outer loop repeatedly slurps the decls for the current gates
276 -- and the instance decls
278 -- The outer loop is needed because consider
279 -- instance Foo a => Baz (Maybe a) where ...
280 -- It may be that @Baz@ and @Maybe@ are used in the source module,
281 -- but not @Foo@; so we need to chase @Foo@ too.
283 -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
284 -- include actually getting in Foo's class decl
285 -- class Wib a => Foo a where ..
286 -- so that its superclasses are discovered. The point is that Wib is a gate too.
287 -- We do this for tycons too, so that we look through type synonyms.
289 go_outer decls fvs all_gates []
290 = returnRn (decls, fvs)
292 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
293 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
294 go_inner decls fvs emptyFVs refs `thenRn` \ (decls1, fvs1, gates1) ->
295 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
296 rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
297 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
298 (nameSetToList (gates2 `minusNameSet` all_gates))
299 -- Knock out the all_gates because even if we don't slurp any new
300 -- decls we can get some apparently-new gates from wired-in names
302 go_inner decls fvs gates []
303 = returnRn (decls, fvs, gates)
305 go_inner decls fvs gates (wanted_name:refs)
306 | isWiredInName wanted_name
307 = load_home wanted_name `thenRn_`
308 go_inner decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
311 = importDecl wanted_name `thenRn` \ maybe_decl ->
313 Nothing -> go_inner decls fvs gates refs -- No declaration... (already slurped, or local)
314 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
315 go_inner (new_decl : decls)
317 (gates `plusFV` getGates source_fvs new_decl)
320 -- When we find a wired-in name we must load its
321 -- home module so that we find any instance decls therein
323 | name `elemNameSet` source_binders = returnRn ()
324 -- When compiling the prelude, a wired-in thing may
325 -- be defined in this module, in which case we don't
326 -- want to load its home module!
327 -- Using 'isLocallyDefined' doesn't work because some of
328 -- the free variables returned are simply 'listTyCon_Name',
329 -- with a system provenance. We could look them up every time
330 -- but that seems a waste.
331 | otherwise = loadHomeInterface doc name `thenRn_`
334 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
336 rnInstDecls decls fvs gates []
337 = returnRn (decls, fvs, gates)
338 rnInstDecls decls fvs gates (d:ds)
339 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
340 rnInstDecls (new_decl:decls)
342 (gates `plusFV` getInstDeclGates new_decl)
348 -------------------------------------------------------
349 -- closeDecls keeps going until the free-var set is empty
350 closeDecls decls needed
351 | not (isEmptyFVs needed)
352 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
353 closeDecls decls1 needed1
356 = getImportedRules `thenRn` \ rule_decls ->
358 [] -> returnRn decls -- No new rules, so we are done
359 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
360 closeDecls decls1 needed1
363 -------------------------------------------------------
364 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
365 -> [(Module, RdrNameHsDecl)]
366 -> RnM d ([RenamedHsDecl], FreeVars)
367 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
368 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
369 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
371 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
374 -------------------------------------------------------
375 -- Augment decls with any decls needed by needed.
376 -- Return also free vars of the new decls (only)
377 slurpDecls decls needed
378 = go decls emptyFVs (nameSetToList needed)
380 go decls fvs [] = returnRn (decls, fvs)
381 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
384 -------------------------------------------------------
385 slurpDecl decls fvs wanted_name
386 = importDecl wanted_name `thenRn` \ maybe_decl ->
388 -- No declaration... (wired in thing)
389 Nothing -> returnRn (decls, fvs)
391 -- Found a declaration... rename it
392 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
393 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
397 %*********************************************************
399 \subsection{Extracting the `gates'}
401 %*********************************************************
403 When we import a declaration like
405 data T = T1 Wibble | T2 Wobble
407 we don't want to treat @Wibble@ and @Wobble@ as gates
408 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
409 If only @T@ is mentioned
410 we want only @T@ to be a gate;
411 that way we don't suck in useless instance
412 decls for (say) @Eq Wibble@, when they can't possibly be useful.
414 @getGates@ takes a newly imported (and renamed) decl, and the free
415 vars of the source program, and extracts from the decl the gate names.
418 getGates source_fvs (SigD (IfaceSig _ ty _ _))
419 = extractHsTyNames ty
421 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs _ sigs _ _ _ _ _ _))
422 = (delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
423 (map getTyVarName tvs)
424 `addOneToNameSet` cls)
425 `plusFV` maybe_double
427 get (ClassOpSig n _ _ ty _)
428 | n `elemNameSet` source_fvs = extractHsTyNames ty
429 | otherwise = emptyFVs
431 -- If we load any numeric class that doesn't have
432 -- Int as an instance, add Double to the gates.
433 -- This takes account of the fact that Double might be needed for
434 -- defaulting, but we don't want to load Double (and all its baggage)
435 -- if the more exotic classes aren't used at all.
436 maybe_double | nameUnique cls `elem` fractionalClassKeys
437 = unitFV (getName doubleTyCon)
441 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
442 = delListFromNameSet (extractHsTyNames ty)
443 (map getTyVarName tvs)
444 -- A type synonym type constructor isn't a "gate" for instance decls
446 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
447 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
448 (map getTyVarName tvs)
449 `addOneToNameSet` tycon
451 get (ConDecl n tvs ctxt details _)
452 | n `elemNameSet` source_fvs
453 -- If the constructor is method, get fvs from all its fields
454 = delListFromNameSet (get_details details `plusFV`
455 extractHsCtxtTyNames ctxt)
456 (map getTyVarName tvs)
457 get (ConDecl n tvs ctxt (RecCon fields) _)
458 -- Even if the constructor isn't mentioned, the fields
459 -- might be, as selectors. They can't mention existentially
460 -- bound tyvars (typechecker checks for that) so no need for
461 -- the deleteListFromNameSet part
462 = foldr (plusFV . get_field) emptyFVs fields
464 get other_con = emptyFVs
466 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
467 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
468 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
469 get_details (NewCon t _) = extractHsTyNames t
471 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
472 | otherwise = emptyFVs
474 get_bang (Banged t) = extractHsTyNames t
475 get_bang (Unbanged t) = extractHsTyNames t
476 get_bang (Unpacked t) = extractHsTyNames t
478 getGates source_fvs other_decl = emptyFVs
481 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
482 rather than a declaration.
485 getWiredInGates :: Name -> FreeVars
486 getWiredInGates name -- No classes are wired in
487 | is_id = getWiredInGates_s (namesOfType (idType the_id))
488 | isSynTyCon the_tycon = getWiredInGates_s
489 (delListFromNameSet (namesOfType ty) (map getName tyvars))
490 | otherwise = unitFV name
492 maybe_wired_in_id = maybeWiredInIdName name
493 is_id = maybeToBool maybe_wired_in_id
494 maybe_wired_in_tycon = maybeWiredInTyConName name
495 Just the_id = maybe_wired_in_id
496 Just the_tycon = maybe_wired_in_tycon
497 (tyvars,ty) = getSynTyConDefn the_tycon
499 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
503 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
504 getInstDeclGates other = emptyFVs
508 %*********************************************************
510 \subsection{Unused names}
512 %*********************************************************
515 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _ _) mentioned_names
517 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
519 -- Now, a use of C implies a use of T,
520 -- if C was brought into scope by T(..) or T(C)
521 really_used_names = used_names `unionNameSets`
522 mkNameSet [ availName avail
523 | sub_name <- nameSetToList used_names,
524 let avail = case lookupNameEnv avail_env sub_name of
526 Nothing -> WARN( True, text "reportUnusedName: not in avail_env" <+> ppr sub_name )
530 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
531 defined_but_not_used =
532 nameSetToList (defined_names `minusNameSet` really_used_names)
534 -- Filter out the ones only defined implicitly
535 bad_locals = [n | n <- defined_but_not_used, isLocallyDefined n]
536 bad_imps = [n | n <- defined_but_not_used, isUserImportedExplicitlyName n]
538 warnUnusedLocalBinds bad_locals `thenRn_`
539 warnUnusedImports bad_imps
541 rnDump :: [RenamedHsDecl] -- Renamed imported decls
542 -> [RenamedHsDecl] -- Renamed local decls
544 rnDump imp_decls decls
545 | opt_D_dump_rn_trace ||
546 opt_D_dump_rn_stats ||
548 = getRnStats imp_decls `thenRn` \ stats_msg ->
550 returnRn (printErrs stats_msg >>
551 dumpIfSet opt_D_dump_rn "Renamer:" (vcat (map ppr decls)))
553 | otherwise = returnRn (return ())
557 %*********************************************************
559 \subsection{Statistics}
561 %*********************************************************
564 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
565 getRnStats imported_decls
566 = getIfacesRn `thenRn` \ ifaces ->
568 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
570 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
571 -- Data, newtype, and class decls are in the decls_fm
572 -- under multiple names; the tycon/class, and each
573 -- constructor/class op too.
574 -- The 'True' selects just the 'main' decl
575 not (isLocallyDefined (availName avail))
578 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
579 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
581 unslurped_insts = iInsts ifaces
582 inst_decls_unslurped = length (bagToList unslurped_insts)
583 inst_decls_read = id_sp + inst_decls_unslurped
586 [int n_mods <+> text "interfaces read",
587 hsep [ int cd_sp, text "class decls imported, out of",
588 int cd_rd, text "read"],
589 hsep [ int dd_sp, text "data decls imported, out of",
590 int dd_rd, text "read"],
591 hsep [ int nd_sp, text "newtype decls imported, out of",
592 int nd_rd, text "read"],
593 hsep [int sd_sp, text "type synonym decls imported, out of",
594 int sd_rd, text "read"],
595 hsep [int vd_sp, text "value signatures imported, out of",
596 int vd_rd, text "read"],
597 hsep [int id_sp, text "instance decls imported, out of",
598 int inst_decls_read, text "read"],
599 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
600 [d | TyClD d <- imported_decls, isClassDecl d]),
601 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
602 [d | TyClD d <- decls_read, isClassDecl d])]
604 returnRn (hcat [text "Renamer stats: ", stats])
614 tycl_decls = [d | TyClD d <- decls]
615 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
617 val_decls = length [() | SigD _ <- decls]
618 inst_decls = length [() | InstD _ <- decls]