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 warnUnusedTopNames, 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,
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, numClass_RDR, thinAirIdNames, 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 )
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, dump_action), rn_errs_bag, rn_warns_bag) ->
78 printErrorsAndWarnings rn_errs_bag rn_warns_bag >>
80 -- Dump any debugging output
84 if not (isEmptyBag rn_errs_bag) then
85 ghcExit 1 >> return Nothing
92 rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
93 = -- FIND THE GLOBAL NAME ENVIRONMENT
94 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
96 -- CHECK FOR EARLY EXIT
97 if not (maybeToBool maybe_stuff) then
98 -- Everything is up to date; no need to recompile further
99 rnDump [] [] `thenRn` \ dump_action ->
100 returnRn (Nothing, dump_action)
103 Just (export_env, gbl_env, fixity_env, global_avail_env) = maybe_stuff
107 initRnMS gbl_env fixity_env SourceMode (
108 rnSourceDecls local_decls
109 ) `thenRn` \ (rn_local_decls, source_fvs) ->
111 -- SLURP IN ALL THE NEEDED DECLARATIONS
112 implicitFVs mod_name rn_local_decls `thenRn` \ implicit_fvs ->
114 real_source_fvs = implicit_fvs `plusFV` source_fvs
115 -- It's important to do the "plus" this way round, so that
116 -- when compiling the prelude, locally-defined (), Bool, etc
117 -- override the implicit ones.
119 slurpImpDecls real_source_fvs `thenRn` \ rn_imp_decls ->
121 rn_all_decls = rn_imp_decls ++ rn_local_decls
124 -- EXIT IF ERRORS FOUND
125 checkErrsRn `thenRn` \ no_errs_so_far ->
126 if not no_errs_so_far then
127 -- Found errors already, so exit now
128 rnDump rn_imp_decls rn_all_decls `thenRn` \ dump_action ->
129 returnRn (Nothing, dump_action)
132 -- GENERATE THE VERSION/USAGE INFO
133 getImportVersions mod_name exports `thenRn` \ my_usages ->
134 getNameSupplyRn `thenRn` \ name_supply ->
136 -- REPORT UNUSED NAMES
137 reportUnusedNames gbl_env global_avail_env
141 -- RETURN THE RENAMED MODULE
143 has_orphans = any isOrphanDecl rn_local_decls
144 direct_import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
145 renamed_module = HsModule mod_name vers
146 trashed_exports trashed_imports
150 rnDump rn_imp_decls rn_all_decls `thenRn` \ dump_action ->
151 returnRn (Just (mkThisModule mod_name,
153 (has_orphans, my_usages, export_env),
155 direct_import_mods), dump_action)
157 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
158 trashed_imports = {-trace "rnSource:trashed_imports"-} []
161 @implicitFVs@ forces the renamer to slurp in some things which aren't
162 mentioned explicitly, but which might be needed by the type checker.
165 implicitFVs mod_name decls
166 = mapRn lookupImplicitOccRn implicit_occs `thenRn` \ implicit_names ->
167 returnRn (implicit_main `plusFV`
168 mkNameSet default_tys `plusFV`
169 mkNameSet thinAirIdNames `plusFV`
170 mkNameSet implicit_names)
173 -- Add occurrences for Int, Double, and (), because they
174 -- are the types to which ambigious type variables may be defaulted by
175 -- the type checker; so they won't always appear explicitly.
176 -- [The () one is a GHC extension for defaulting CCall results.]
177 -- ALSO: funTyCon, since it occurs implicitly everywhere!
178 -- (we don't want to be bothered with making funTyCon a
179 -- free var at every function application!)
180 default_tys = [getName intTyCon, getName doubleTyCon,
181 getName unitTyCon, getName funTyCon, getName boolTyCon]
183 -- Add occurrences for IO or PrimIO
184 implicit_main | mod_name == mAIN_Name
185 || mod_name == pREL_MAIN_Name = unitFV ioTyCon_NAME
186 | otherwise = emptyFVs
188 -- Now add extra "occurrences" for things that
189 -- the deriving mechanism, or defaulting, will later need in order to
191 implicit_occs = foldr ((++) . get) [] decls
193 get (DefD _) = [numClass_RDR]
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 check (HsVar v) = not (isLocallyDefined v)
215 check (HsApp f a) = check f && check a
217 isOrphanDecl other = False
221 %*********************************************************
223 \subsection{Slurping declarations}
225 %*********************************************************
228 -------------------------------------------------------
229 slurpImpDecls source_fvs
230 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
232 -- The current slurped-set records all local things
233 getSlurped `thenRn` \ source_binders ->
234 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
236 -- And finally get everything else
237 closeDecls decls needed
239 -------------------------------------------------------
240 slurpSourceRefs :: NameSet -- Variables defined in source
241 -> FreeVars -- Variables referenced in source
242 -> RnMG ([RenamedHsDecl],
243 FreeVars) -- Un-satisfied needs
244 -- The declaration (and hence home module) of each gate has
245 -- already been loaded
247 slurpSourceRefs source_binders source_fvs
248 = go_outer [] -- Accumulating decls
249 emptyFVs -- Unsatisfied needs
250 emptyFVs -- Accumulating gates
251 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
253 -- The outer loop repeatedly slurps the decls for the current gates
254 -- and the instance decls
256 -- The outer loop is needed because consider
257 -- instance Foo a => Baz (Maybe a) where ...
258 -- It may be that @Baz@ and @Maybe@ are used in the source module,
259 -- but not @Foo@; so we need to chase @Foo@ too.
261 -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
262 -- include actually getting in Foo's class decl
263 -- class Wib a => Foo a where ..
264 -- so that its superclasses are discovered. The point is that Wib is a gate too.
265 -- We do this for tycons too, so that we look through type synonyms.
267 go_outer decls fvs all_gates []
268 = returnRn (decls, fvs)
270 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
271 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
272 go_inner decls fvs emptyFVs refs `thenRn` \ (decls1, fvs1, gates1) ->
273 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
274 rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
275 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
276 (nameSetToList (gates2 `minusNameSet` all_gates))
277 -- Knock out the all_gates because even ifwe don't slurp any new
278 -- decls we can get some apparently-new gates from wired-in names
280 go_inner decls fvs gates []
281 = returnRn (decls, fvs, gates)
283 go_inner decls fvs gates (wanted_name:refs)
284 | isWiredInName wanted_name
285 = load_home wanted_name `thenRn_`
286 go_inner decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
289 = importDecl wanted_name `thenRn` \ maybe_decl ->
291 Nothing -> go_inner decls fvs gates refs -- No declaration... (already slurped, or local)
292 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
293 go_inner (new_decl : decls)
295 (gates `plusFV` getGates source_fvs new_decl)
298 -- When we find a wired-in name we must load its
299 -- home module so that we find any instance decls therein
301 | name `elemNameSet` source_binders = returnRn ()
302 -- When compiling the prelude, a wired-in thing may
303 -- be defined in this module, in which case we don't
304 -- want to load its home module!
305 -- Using 'isLocallyDefined' doesn't work because some of
306 -- the free variables returned are simply 'listTyCon_Name',
307 -- with a system provenance. We could look them up every time
308 -- but that seems a waste.
309 | otherwise = loadHomeInterface doc name `thenRn_`
312 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
314 rnInstDecls decls fvs gates []
315 = returnRn (decls, fvs, gates)
316 rnInstDecls decls fvs gates (d:ds)
317 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
318 rnInstDecls (new_decl:decls)
320 (gates `plusFV` getInstDeclGates new_decl)
326 -------------------------------------------------------
327 -- closeDecls keeps going until the free-var set is empty
328 closeDecls decls needed
329 | not (isEmptyFVs needed)
330 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
331 closeDecls decls1 needed1
334 = getImportedRules `thenRn` \ rule_decls ->
336 [] -> returnRn decls -- No new rules, so we are done
337 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
338 closeDecls decls1 needed1
341 -------------------------------------------------------
342 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
343 -> [(Module, RdrNameHsDecl)]
344 -> RnM d ([RenamedHsDecl], FreeVars)
345 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
346 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
347 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
349 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
352 -------------------------------------------------------
353 -- Augment decls with any decls needed by needed.
354 -- Return also free vars of the new decls (only)
355 slurpDecls decls needed
356 = go decls emptyFVs (nameSetToList needed)
358 go decls fvs [] = returnRn (decls, fvs)
359 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
362 -------------------------------------------------------
363 slurpDecl decls fvs wanted_name
364 = importDecl wanted_name `thenRn` \ maybe_decl ->
366 -- No declaration... (wired in thing)
367 Nothing -> returnRn (decls, fvs)
369 -- Found a declaration... rename it
370 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
371 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
375 %*********************************************************
377 \subsection{Extracting the `gates'}
379 %*********************************************************
381 When we import a declaration like
383 data T = T1 Wibble | T2 Wobble
385 we don't want to treat @Wibble@ and @Wobble@ as gates
386 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
387 If only @T@ is mentioned
388 we want only @T@ to be a gate;
389 that way we don't suck in useless instance
390 decls for (say) @Eq Wibble@, when they can't possibly be useful.
392 @getGates@ takes a newly imported (and renamed) decl, and the free
393 vars of the source program, and extracts from the decl the gate names.
396 getGates source_fvs (SigD (IfaceSig _ ty _ _))
397 = extractHsTyNames ty
399 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs _ sigs _ _ _ _ _ _))
400 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
401 (map getTyVarName tvs)
402 `addOneToNameSet` cls
404 get (ClassOpSig n _ _ ty _)
405 | n `elemNameSet` source_fvs = extractHsTyNames ty
406 | otherwise = emptyFVs
408 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
409 = delListFromNameSet (extractHsTyNames ty)
410 (map getTyVarName tvs)
411 -- A type synonym type constructor isn't a "gate" for instance decls
413 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
414 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
415 (map getTyVarName tvs)
416 `addOneToNameSet` tycon
418 get (ConDecl n tvs ctxt details _)
419 | n `elemNameSet` source_fvs
420 -- If the constructor is method, get fvs from all its fields
421 = delListFromNameSet (get_details details `plusFV`
422 extractHsCtxtTyNames ctxt)
423 (map getTyVarName tvs)
424 get (ConDecl n tvs ctxt (RecCon fields) _)
425 -- Even if the constructor isn't mentioned, the fields
426 -- might be, as selectors. They can't mention existentially
427 -- bound tyvars (typechecker checks for that) so no need for
428 -- the deleteListFromNameSet part
429 = foldr (plusFV . get_field) emptyFVs fields
431 get other_con = emptyFVs
433 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
434 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
435 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
436 get_details (NewCon t _) = extractHsTyNames t
438 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
439 | otherwise = emptyFVs
441 get_bang (Banged t) = extractHsTyNames t
442 get_bang (Unbanged t) = extractHsTyNames t
443 get_bang (Unpacked t) = extractHsTyNames t
445 getGates source_fvs other_decl = emptyFVs
448 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
449 rather than a declaration.
452 getWiredInGates :: Name -> FreeVars
453 getWiredInGates name -- No classes are wired in
454 | is_id = getWiredInGates_s (namesOfType (idType the_id))
455 | isSynTyCon the_tycon = getWiredInGates_s
456 (delListFromNameSet (namesOfType ty) (map getName tyvars))
457 | otherwise = unitFV name
459 maybe_wired_in_id = maybeWiredInIdName name
460 is_id = maybeToBool maybe_wired_in_id
461 maybe_wired_in_tycon = maybeWiredInTyConName name
462 Just the_id = maybe_wired_in_id
463 Just the_tycon = maybe_wired_in_tycon
464 (tyvars,ty) = getSynTyConDefn the_tycon
466 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
470 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
471 getInstDeclGates other = emptyFVs
475 %*********************************************************
477 \subsection{Unused names}
479 %*********************************************************
482 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _) mentioned_names
484 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
486 -- Now, a use of C implies a use of T,
487 -- if C was brought into scope by T(..) or T(C)
488 really_used_names = used_names `unionNameSets`
489 mkNameSet [ availName avail
490 | sub_name <- nameSetToList used_names,
491 let avail = case lookupNameEnv avail_env sub_name of
493 Nothing -> WARN( True, text "reportUnusedName: not in avail_env" <+> ppr sub_name )
497 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
498 defined_but_not_used =
499 nameSetToList (defined_names `minusNameSet` really_used_names)
501 -- Filter out the ones only defined implicitly
502 bad_guys = filter reportableUnusedName defined_but_not_used
504 warnUnusedTopNames bad_guys
506 reportableUnusedName :: Name -> Bool
507 reportableUnusedName name
508 = explicitlyImported (getNameProvenance name)
510 explicitlyImported (LocalDef _ _) = True
511 -- Report unused defns of local vars
512 explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl
513 -- Report unused explicit imports
514 explicitlyImported other = False
515 -- Don't report others
517 rnDump :: [RenamedHsDecl] -- Renamed imported decls
518 -> [RenamedHsDecl] -- Renamed local decls
520 rnDump imp_decls decls
521 | opt_D_dump_rn_trace ||
522 opt_D_dump_rn_stats ||
524 = getRnStats imp_decls `thenRn` \ stats_msg ->
526 returnRn (printErrs stats_msg >>
527 dumpIfSet opt_D_dump_rn "Renamer:" (vcat (map ppr decls)))
529 | otherwise = returnRn (return ())
533 %*********************************************************
535 \subsection{Statistics}
537 %*********************************************************
540 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
541 getRnStats imported_decls
542 = getIfacesRn `thenRn` \ ifaces ->
544 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
546 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
547 -- Data, newtype, and class decls are in the decls_fm
548 -- under multiple names; the tycon/class, and each
549 -- constructor/class op too.
550 -- The 'True' selects just the 'main' decl
551 not (isLocallyDefined (availName avail))
554 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
555 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
557 unslurped_insts = iInsts ifaces
558 inst_decls_unslurped = length (bagToList unslurped_insts)
559 inst_decls_read = id_sp + inst_decls_unslurped
562 [int n_mods <+> text "interfaces read",
563 hsep [ int cd_sp, text "class decls imported, out of",
564 int cd_rd, text "read"],
565 hsep [ int dd_sp, text "data decls imported, out of",
566 int dd_rd, text "read"],
567 hsep [ int nd_sp, text "newtype decls imported, out of",
568 int nd_rd, text "read"],
569 hsep [int sd_sp, text "type synonym decls imported, out of",
570 int sd_rd, text "read"],
571 hsep [int vd_sp, text "value signatures imported, out of",
572 int vd_rd, text "read"],
573 hsep [int id_sp, text "instance decls imported, out of",
574 int inst_decls_read, text "read"],
575 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
576 [d | TyClD d <- imported_decls, isClassDecl d]),
577 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
578 [d | TyClD d <- decls_read, isClassDecl d])]
580 returnRn (hcat [text "Renamer stats: ", stats])
590 tycl_decls = [d | TyClD d <- decls]
591 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
593 val_decls = length [() | SigD _ <- decls]
594 inst_decls = length [() | InstD _ <- decls]