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, rn_errs_bag, rn_warns_bag) ->
78 printErrorsAndWarnings rn_errs_bag rn_warns_bag >>
80 -- Dump output, if any
81 (case maybe_rn_stuff of
83 Just results@(_, rn_mod, _, _, _)
84 -> dumpIfSet opt_D_dump_rn "Renamer:"
89 if not (isEmptyBag rn_errs_bag) then
90 ghcExit 1 >> return Nothing
97 rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
98 = -- FIND THE GLOBAL NAME ENVIRONMENT
99 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
101 -- CHECK FOR EARLY EXIT
102 if not (maybeToBool maybe_stuff) then
103 -- Everything is up to date; no need to recompile further
108 Just (export_env, gbl_env, fixity_env, global_avail_env) = maybe_stuff
112 initRnMS gbl_env fixity_env SourceMode (
113 rnSourceDecls local_decls
114 ) `thenRn` \ (rn_local_decls, source_fvs) ->
116 -- SLURP IN ALL THE NEEDED DECLARATIONS
117 implicitFVs mod_name rn_local_decls `thenRn` \ implicit_fvs ->
119 real_source_fvs = implicit_fvs `plusFV` source_fvs
120 -- It's important to do the "plus" this way round, so that
121 -- when compiling the prelude, locally-defined (), Bool, etc
122 -- override the implicit ones.
124 slurpImpDecls real_source_fvs `thenRn` \ rn_imp_decls ->
126 -- EXIT IF ERRORS FOUND
127 checkErrsRn `thenRn` \ no_errs_so_far ->
128 if not no_errs_so_far then
129 -- Found errors already, so exit now
134 -- GENERATE THE VERSION/USAGE INFO
135 getImportVersions mod_name exports `thenRn` \ my_usages ->
136 getNameSupplyRn `thenRn` \ name_supply ->
138 -- REPORT UNUSED NAMES
139 reportUnusedNames gbl_env global_avail_env
143 -- RETURN THE RENAMED MODULE
145 has_orphans = any isOrphanDecl rn_local_decls
146 direct_import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
147 rn_all_decls = rn_imp_decls ++ rn_local_decls
148 renamed_module = HsModule mod_name vers
149 trashed_exports trashed_imports
153 rnStats rn_imp_decls `thenRn_`
154 returnRn (Just (mkThisModule mod_name,
156 (has_orphans, my_usages, export_env),
160 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
161 trashed_imports = {-trace "rnSource:trashed_imports"-} []
164 @implicitFVs@ forces the renamer to slurp in some things which aren't
165 mentioned explicitly, but which might be needed by the type checker.
168 implicitFVs mod_name decls
169 = mapRn lookupImplicitOccRn implicit_occs `thenRn` \ implicit_names ->
170 returnRn (implicit_main `plusFV`
171 mkNameSet default_tys `plusFV`
172 mkNameSet thinAirIdNames `plusFV`
173 mkNameSet implicit_names)
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
191 -- Now add extra "occurrences" for things that
192 -- the deriving mechanism, or defaulting, will later need in order to
194 implicit_occs = foldr ((++) . get) [] decls
196 get (DefD _) = [numClass_RDR]
197 get (TyClD (TyData _ _ _ _ _ (Just deriv_classes) _ _))
198 = concat (map get_deriv deriv_classes)
201 get_deriv cls = case lookupUFM derivingOccurrences cls of
207 isOrphanDecl (InstD (InstDecl inst_ty _ _ _ _))
208 = not (foldNameSet ((||) . isLocallyDefined) False (extractHsTyNames (removeContext inst_ty)))
209 -- The 'removeContext' is because of
210 -- instance Foo a => Baz T where ...
211 -- The decl is an orphan if Baz and T are both not locally defined,
212 -- even if Foo *is* locally defined
214 isOrphanDecl (RuleD (RuleDecl _ _ _ lhs _ _))
217 check (HsVar v) = not (isLocallyDefined v)
218 check (HsApp f a) = check f && check a
220 isOrphanDecl other = False
224 %*********************************************************
226 \subsection{Slurping declarations}
228 %*********************************************************
231 -------------------------------------------------------
232 slurpImpDecls source_fvs
233 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
235 -- The current slurped-set records all local things
236 getSlurped `thenRn` \ source_binders ->
237 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
239 -- And finally get everything else
240 closeDecls decls needed
242 -------------------------------------------------------
243 slurpSourceRefs :: NameSet -- Variables defined in source
244 -> FreeVars -- Variables referenced in source
245 -> RnMG ([RenamedHsDecl],
246 FreeVars) -- Un-satisfied needs
247 -- The declaration (and hence home module) of each gate has
248 -- already been loaded
250 slurpSourceRefs source_binders source_fvs
251 = go_outer [] -- Accumulating decls
252 emptyFVs -- Unsatisfied needs
253 emptyFVs -- Accumulating gates
254 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
256 -- The outer loop repeatedly slurps the decls for the current gates
257 -- and the instance decls
259 -- The outer loop is needed because consider
260 -- instance Foo a => Baz (Maybe a) where ...
261 -- It may be that @Baz@ and @Maybe@ are used in the source module,
262 -- but not @Foo@; so we need to chase @Foo@ too.
264 -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
265 -- include actually getting in Foo's class decl
266 -- class Wib a => Foo a where ..
267 -- so that its superclasses are discovered. The point is that Wib is a gate too.
268 -- We do this for tycons too, so that we look through type synonyms.
270 go_outer decls fvs all_gates []
271 = returnRn (decls, fvs)
273 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
274 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
275 go_inner decls fvs emptyFVs refs `thenRn` \ (decls1, fvs1, gates1) ->
276 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
277 rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
278 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
279 (nameSetToList (gates2 `minusNameSet` all_gates))
280 -- Knock out the all_gates because even ifwe don't slurp any new
281 -- decls we can get some apparently-new gates from wired-in names
283 go_inner decls fvs gates []
284 = returnRn (decls, fvs, gates)
286 go_inner decls fvs gates (wanted_name:refs)
287 | isWiredInName wanted_name
288 = load_home wanted_name `thenRn_`
289 go_inner decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
292 = importDecl wanted_name `thenRn` \ maybe_decl ->
294 Nothing -> go_inner decls fvs gates refs -- No declaration... (already slurped, or local)
295 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
296 go_inner (new_decl : decls)
298 (gates `plusFV` getGates source_fvs new_decl)
301 -- When we find a wired-in name we must load its
302 -- home module so that we find any instance decls therein
304 | name `elemNameSet` source_binders = returnRn ()
305 -- When compiling the prelude, a wired-in thing may
306 -- be defined in this module, in which case we don't
307 -- want to load its home module!
308 -- Using 'isLocallyDefined' doesn't work because some of
309 -- the free variables returned are simply 'listTyCon_Name',
310 -- with a system provenance. We could look them up every time
311 -- but that seems a waste.
312 | otherwise = loadHomeInterface doc name `thenRn_`
315 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
317 rnInstDecls decls fvs gates []
318 = returnRn (decls, fvs, gates)
319 rnInstDecls decls fvs gates (d:ds)
320 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
321 rnInstDecls (new_decl:decls)
323 (gates `plusFV` getInstDeclGates new_decl)
329 -------------------------------------------------------
330 -- closeDecls keeps going until the free-var set is empty
331 closeDecls decls needed
332 | not (isEmptyFVs needed)
333 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
334 closeDecls decls1 needed1
337 = getImportedRules `thenRn` \ rule_decls ->
339 [] -> returnRn decls -- No new rules, so we are done
340 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
341 closeDecls decls1 needed1
344 -------------------------------------------------------
345 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
346 -> [(Module, RdrNameHsDecl)]
347 -> RnM d ([RenamedHsDecl], FreeVars)
348 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
349 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
350 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
352 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
355 -------------------------------------------------------
356 -- Augment decls with any decls needed by needed.
357 -- Return also free vars of the new decls (only)
358 slurpDecls decls needed
359 = go decls emptyFVs (nameSetToList needed)
361 go decls fvs [] = returnRn (decls, fvs)
362 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
365 -------------------------------------------------------
366 slurpDecl decls fvs wanted_name
367 = importDecl wanted_name `thenRn` \ maybe_decl ->
369 -- No declaration... (wired in thing)
370 Nothing -> returnRn (decls, fvs)
372 -- Found a declaration... rename it
373 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
374 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
378 %*********************************************************
380 \subsection{Extracting the `gates'}
382 %*********************************************************
384 When we import a declaration like
386 data T = T1 Wibble | T2 Wobble
388 we don't want to treat @Wibble@ and @Wobble@ as gates
389 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
390 If only @T@ is mentioned
391 we want only @T@ to be a gate;
392 that way we don't suck in useless instance
393 decls for (say) @Eq Wibble@, when they can't possibly be useful.
395 @getGates@ takes a newly imported (and renamed) decl, and the free
396 vars of the source program, and extracts from the decl the gate names.
399 getGates source_fvs (SigD (IfaceSig _ ty _ _))
400 = extractHsTyNames ty
402 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs sigs _ _ _ _ _ _))
403 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
404 (map getTyVarName tvs)
405 `addOneToNameSet` cls
407 get (ClassOpSig n _ _ ty _)
408 | n `elemNameSet` source_fvs = extractHsTyNames ty
409 | otherwise = emptyFVs
411 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
412 = delListFromNameSet (extractHsTyNames ty)
413 (map getTyVarName tvs)
414 -- A type synonym type constructor isn't a "gate" for instance decls
416 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
417 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
418 (map getTyVarName tvs)
419 `addOneToNameSet` tycon
421 get (ConDecl n tvs ctxt details _)
422 | n `elemNameSet` source_fvs
423 -- If the constructor is method, get fvs from all its fields
424 = delListFromNameSet (get_details details `plusFV`
425 extractHsCtxtTyNames ctxt)
426 (map getTyVarName tvs)
427 get (ConDecl n tvs ctxt (RecCon fields) _)
428 -- Even if the constructor isn't mentioned, the fields
429 -- might be, as selectors. They can't mention existentially
430 -- bound tyvars (typechecker checks for that) so no need for
431 -- the deleteListFromNameSet part
432 = foldr (plusFV . get_field) emptyFVs fields
434 get other_con = emptyFVs
436 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
437 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
438 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
439 get_details (NewCon t _) = extractHsTyNames t
441 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
442 | otherwise = emptyFVs
444 get_bang (Banged t) = extractHsTyNames t
445 get_bang (Unbanged t) = extractHsTyNames t
446 get_bang (Unpacked t) = extractHsTyNames t
448 getGates source_fvs other_decl = emptyFVs
451 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
452 rather than a declaration.
455 getWiredInGates :: Name -> FreeVars
456 getWiredInGates name -- No classes are wired in
457 | is_id = getWiredInGates_s (namesOfType (idType the_id))
458 | isSynTyCon the_tycon = getWiredInGates_s
459 (delListFromNameSet (namesOfType ty) (map getName tyvars))
460 | otherwise = unitFV name
462 maybe_wired_in_id = maybeWiredInIdName name
463 is_id = maybeToBool maybe_wired_in_id
464 maybe_wired_in_tycon = maybeWiredInTyConName name
465 Just the_id = maybe_wired_in_id
466 Just the_tycon = maybe_wired_in_tycon
467 (tyvars,ty) = getSynTyConDefn the_tycon
469 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
473 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
474 getInstDeclGates other = emptyFVs
478 %*********************************************************
480 \subsection{Unused names}
482 %*********************************************************
485 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _) mentioned_names
487 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
489 -- Now, a use of C implies a use of T,
490 -- if C was brought into scope by T(..) or T(C)
491 really_used_names = used_names `unionNameSets`
492 mkNameSet [ availName avail
493 | sub_name <- nameSetToList used_names,
494 let avail = case lookupNameEnv avail_env sub_name of
496 Nothing -> WARN( True, text "reportUnusedName: not in avail_env" <+> ppr sub_name )
500 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
501 defined_but_not_used =
502 nameSetToList (defined_names `minusNameSet` really_used_names)
504 -- Filter out the ones only defined implicitly
505 bad_guys = filter reportableUnusedName defined_but_not_used
507 warnUnusedTopNames bad_guys
509 reportableUnusedName :: Name -> Bool
510 reportableUnusedName name
511 = explicitlyImported (getNameProvenance name)
513 explicitlyImported (LocalDef _ _) = True
514 -- Report unused defns of local vars
515 explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl
516 -- Report unused explicit imports
517 explicitlyImported other = False
518 -- Don't report others
520 rnStats :: [RenamedHsDecl] -> RnMG ()
522 | opt_D_dump_rn_trace ||
523 opt_D_dump_rn_stats ||
525 = getRnStats imp_decls `thenRn` \ msg ->
526 ioToRnM (printErrs msg) `thenRn_`
529 | otherwise = returnRn ()
534 %*********************************************************
536 \subsection{Statistics}
538 %*********************************************************
541 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
542 getRnStats imported_decls
543 = getIfacesRn `thenRn` \ ifaces ->
545 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
547 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
548 -- Data, newtype, and class decls are in the decls_fm
549 -- under multiple names; the tycon/class, and each
550 -- constructor/class op too.
551 -- The 'True' selects just the 'main' decl
552 not (isLocallyDefined (availName avail))
555 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
556 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
558 unslurped_insts = iInsts ifaces
559 inst_decls_unslurped = length (bagToList unslurped_insts)
560 inst_decls_read = id_sp + inst_decls_unslurped
563 [int n_mods <+> text "interfaces read",
564 hsep [ int cd_sp, text "class decls imported, out of",
565 int cd_rd, text "read"],
566 hsep [ int dd_sp, text "data decls imported, out of",
567 int dd_rd, text "read"],
568 hsep [ int nd_sp, text "newtype decls imported, out of",
569 int nd_rd, text "read"],
570 hsep [int sd_sp, text "type synonym decls imported, out of",
571 int sd_rd, text "read"],
572 hsep [int vd_sp, text "value signatures imported, out of",
573 int vd_rd, text "read"],
574 hsep [int id_sp, text "instance decls imported, out of",
575 int inst_decls_read, text "read"],
576 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
577 [d | TyClD d <- imported_decls, isClassDecl d]),
578 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
579 [d | TyClD d <- decls_read, isClassDecl d])]
581 returnRn (hcat [text "Renamer stats: ", stats])
591 tycl_decls = [d | TyClD d <- decls]
592 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
594 val_decls = length [() | SigD _ <- decls]
595 inst_decls = length [() | InstD _ <- decls]