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 ( pprBagOfErrors, pprBagOfWarnings,
48 doIfSet, dumpIfSet, ghcExit
50 import BasicTypes ( NewOrData(..) )
51 import Bag ( isEmptyBag, bagToList )
52 import FiniteMap ( fmToList, delListFromFM, addToFM, sizeFM, eltsFM )
53 import UniqSupply ( UniqSupply )
54 import UniqFM ( lookupUFM )
55 import Util ( equivClasses )
56 import Maybes ( maybeToBool )
63 renameModule :: UniqSupply
67 , RenamedHsModule -- Output, after renaming
68 , InterfaceDetails -- Interface; for interface file generation
69 , RnNameSupply -- Final env; for renaming derivings
70 , [ModuleName] -- Imported modules; for profiling
73 renameModule us this_mod@(HsModule mod_name vers exports imports local_decls loc)
74 = -- Initialise the renamer monad
75 initRn mod_name us (mkSearchPath opt_HiMap) loc
77 \ (maybe_rn_stuff, rn_errs_bag, rn_warns_bag) ->
80 doIfSet (not (isEmptyBag rn_warns_bag))
81 (printErrs (pprBagOfWarnings rn_warns_bag)) >>
83 -- Check for errors; exit if so
84 doIfSet (not (isEmptyBag rn_errs_bag))
85 (printErrs (pprBagOfErrors rn_errs_bag) >>
89 -- Dump output, if any
90 (case maybe_rn_stuff of
92 Just results@(_, rn_mod, _, _, _)
93 -> dumpIfSet opt_D_dump_rn "Renamer:"
103 rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
104 = -- FIND THE GLOBAL NAME ENVIRONMENT
105 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
107 -- CHECK FOR EARLY EXIT
108 if not (maybeToBool maybe_stuff) then
109 -- Everything is up to date; no need to recompile further
114 Just (export_env, gbl_env, fixity_env, global_avail_env) = maybe_stuff
118 initRnMS gbl_env fixity_env SourceMode (
119 rnSourceDecls local_decls
120 ) `thenRn` \ (rn_local_decls, source_fvs) ->
122 -- SLURP IN ALL THE NEEDED DECLARATIONS
123 implicitFVs mod_name rn_local_decls `thenRn` \ implicit_fvs ->
125 real_source_fvs = implicit_fvs `plusFV` source_fvs
126 -- It's important to do the "plus" this way round, so that
127 -- when compiling the prelude, locally-defined (), Bool, etc
128 -- override the implicit ones.
130 slurpImpDecls real_source_fvs `thenRn` \ rn_imp_decls ->
132 -- EXIT IF ERRORS FOUND
133 checkErrsRn `thenRn` \ no_errs_so_far ->
134 if not no_errs_so_far then
135 -- Found errors already, so exit now
140 -- GENERATE THE VERSION/USAGE INFO
141 getImportVersions mod_name exports `thenRn` \ my_usages ->
142 getNameSupplyRn `thenRn` \ name_supply ->
144 -- REPORT UNUSED NAMES
145 reportUnusedNames gbl_env global_avail_env
149 -- RETURN THE RENAMED MODULE
151 has_orphans = any isOrphanDecl rn_local_decls
152 direct_import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
153 rn_all_decls = rn_imp_decls ++ rn_local_decls
154 renamed_module = HsModule mod_name vers
155 trashed_exports trashed_imports
159 rnStats rn_imp_decls `thenRn_`
160 returnRn (Just (mkThisModule mod_name,
162 (has_orphans, my_usages, export_env),
166 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
167 trashed_imports = {-trace "rnSource:trashed_imports"-} []
170 @implicitFVs@ forces the renamer to slurp in some things which aren't
171 mentioned explicitly, but which might be needed by the type checker.
174 implicitFVs mod_name decls
175 = mapRn lookupImplicitOccRn implicit_occs `thenRn` \ implicit_names ->
176 returnRn (implicit_main `plusFV`
177 mkNameSet default_tys `plusFV`
178 mkNameSet thinAirIdNames `plusFV`
179 mkNameSet implicit_names)
182 -- Add occurrences for Int, Double, and (), because they
183 -- are the types to which ambigious type variables may be defaulted by
184 -- the type checker; so they won't always appear explicitly.
185 -- [The () one is a GHC extension for defaulting CCall results.]
186 -- ALSO: funTyCon, since it occurs implicitly everywhere!
187 -- (we don't want to be bothered with making funTyCon a
188 -- free var at every function application!)
189 default_tys = [getName intTyCon, getName doubleTyCon,
190 getName unitTyCon, getName funTyCon, getName boolTyCon]
192 -- Add occurrences for IO or PrimIO
193 implicit_main | mod_name == mAIN_Name
194 || mod_name == pREL_MAIN_Name = unitFV ioTyCon_NAME
195 | otherwise = emptyFVs
197 -- Now add extra "occurrences" for things that
198 -- the deriving mechanism, or defaulting, will later need in order to
200 implicit_occs = foldr ((++) . get) [] decls
202 get (DefD _) = [numClass_RDR]
203 get (TyClD (TyData _ _ _ _ _ (Just deriv_classes) _ _))
204 = concat (map get_deriv deriv_classes)
207 get_deriv cls = case lookupUFM derivingOccurrences cls of
213 isOrphanDecl (InstD (InstDecl inst_ty _ _ _ _))
214 = not (foldNameSet ((||) . isLocallyDefined) False (extractHsTyNames (removeContext inst_ty)))
215 -- The 'removeContext' is because of
216 -- instance Foo a => Baz T where ...
217 -- The decl is an orphan if Baz and T are both not locally defined,
218 -- even if Foo *is* locally defined
220 isOrphanDecl (RuleD (RuleDecl _ _ _ lhs _ _))
223 check (HsVar v) = not (isLocallyDefined v)
224 check (HsApp f a) = check f && check a
226 isOrphanDecl other = False
230 %*********************************************************
232 \subsection{Slurping declarations}
234 %*********************************************************
237 -------------------------------------------------------
238 slurpImpDecls source_fvs
239 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
241 -- The current slurped-set records all local things
242 getSlurped `thenRn` \ source_binders ->
243 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
245 -- And finally get everything else
246 closeDecls decls needed
248 -------------------------------------------------------
249 slurpSourceRefs :: NameSet -- Variables defined in source
250 -> FreeVars -- Variables referenced in source
251 -> RnMG ([RenamedHsDecl],
252 FreeVars) -- Un-satisfied needs
253 -- The declaration (and hence home module) of each gate has
254 -- already been loaded
256 slurpSourceRefs source_binders source_fvs
257 = go_outer [] -- Accumulating decls
258 emptyFVs -- Unsatisfied needs
259 emptyFVs -- Accumulating gates
260 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
262 -- The outer loop repeatedly slurps the decls for the current gates
263 -- and the instance decls
265 -- The outer loop is needed because consider
266 -- instance Foo a => Baz (Maybe a) where ...
267 -- It may be that @Baz@ and @Maybe@ are used in the source module,
268 -- but not @Foo@; so we need to chase @Foo@ too.
270 -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
271 -- include actually getting in Foo's class decl
272 -- class Wib a => Foo a where ..
273 -- so that its superclasses are discovered. The point is that Wib is a gate too.
274 -- We do this for tycons too, so that we look through type synonyms.
276 go_outer decls fvs all_gates []
277 = returnRn (decls, fvs)
279 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
280 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
281 go_inner decls fvs emptyFVs refs `thenRn` \ (decls1, fvs1, gates1) ->
282 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
283 rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
284 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
285 (nameSetToList (gates2 `minusNameSet` all_gates))
286 -- Knock out the all_gates because even ifwe don't slurp any new
287 -- decls we can get some apparently-new gates from wired-in names
289 go_inner decls fvs gates []
290 = returnRn (decls, fvs, gates)
292 go_inner decls fvs gates (wanted_name:refs)
293 | isWiredInName wanted_name
294 = load_home wanted_name `thenRn_`
295 go_inner decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
298 = importDecl wanted_name `thenRn` \ maybe_decl ->
300 Nothing -> go_inner decls fvs gates refs -- No declaration... (already slurped, or local)
301 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
302 go_inner (new_decl : decls)
304 (gates `plusFV` getGates source_fvs new_decl)
307 -- When we find a wired-in name we must load its
308 -- home module so that we find any instance decls therein
310 | name `elemNameSet` source_binders = returnRn ()
311 -- When compiling the prelude, a wired-in thing may
312 -- be defined in this module, in which case we don't
313 -- want to load its home module!
314 -- Using 'isLocallyDefined' doesn't work because some of
315 -- the free variables returned are simply 'listTyCon_Name',
316 -- with a system provenance. We could look them up every time
317 -- but that seems a waste.
318 | otherwise = loadHomeInterface doc name `thenRn_`
321 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
323 rnInstDecls decls fvs gates []
324 = returnRn (decls, fvs, gates)
325 rnInstDecls decls fvs gates (d:ds)
326 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
327 rnInstDecls (new_decl:decls)
329 (gates `plusFV` getInstDeclGates new_decl)
335 -------------------------------------------------------
336 -- closeDecls keeps going until the free-var set is empty
337 closeDecls decls needed
338 | not (isEmptyFVs needed)
339 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
340 closeDecls decls1 needed1
343 = getImportedRules `thenRn` \ rule_decls ->
345 [] -> returnRn decls -- No new rules, so we are done
346 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
347 closeDecls decls1 needed1
350 -------------------------------------------------------
351 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
352 -> [(Module, RdrNameHsDecl)]
353 -> RnM d ([RenamedHsDecl], FreeVars)
354 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
355 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
356 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
358 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
361 -------------------------------------------------------
362 -- Augment decls with any decls needed by needed.
363 -- Return also free vars of the new decls (only)
364 slurpDecls decls needed
365 = go decls emptyFVs (nameSetToList needed)
367 go decls fvs [] = returnRn (decls, fvs)
368 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
371 -------------------------------------------------------
372 slurpDecl decls fvs wanted_name
373 = importDecl wanted_name `thenRn` \ maybe_decl ->
375 -- No declaration... (wired in thing)
376 Nothing -> returnRn (decls, fvs)
378 -- Found a declaration... rename it
379 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
380 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
384 %*********************************************************
386 \subsection{Extracting the `gates'}
388 %*********************************************************
390 When we import a declaration like
392 data T = T1 Wibble | T2 Wobble
394 we don't want to treat @Wibble@ and @Wobble@ as gates
395 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
396 If only @T@ is mentioned
397 we want only @T@ to be a gate;
398 that way we don't suck in useless instance
399 decls for (say) @Eq Wibble@, when they can't possibly be useful.
401 @getGates@ takes a newly imported (and renamed) decl, and the free
402 vars of the source program, and extracts from the decl the gate names.
405 getGates source_fvs (SigD (IfaceSig _ ty _ _))
406 = extractHsTyNames ty
408 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs sigs _ _ _ _ _ _))
409 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
410 (map getTyVarName tvs)
411 `addOneToNameSet` cls
413 get (ClassOpSig n _ ty _)
414 | n `elemNameSet` source_fvs = extractHsTyNames ty
415 | otherwise = emptyFVs
417 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
418 = delListFromNameSet (extractHsTyNames ty)
419 (map getTyVarName tvs)
420 -- A type synonym type constructor isn't a "gate" for instance decls
422 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
423 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
424 (map getTyVarName tvs)
425 `addOneToNameSet` tycon
427 get (ConDecl n tvs ctxt details _)
428 | n `elemNameSet` source_fvs
429 -- If the constructor is method, get fvs from all its fields
430 = delListFromNameSet (get_details details `plusFV`
431 extractHsCtxtTyNames ctxt)
432 (map getTyVarName tvs)
433 get (ConDecl n tvs ctxt (RecCon fields) _)
434 -- Even if the constructor isn't mentioned, the fields
435 -- might be, as selectors. They can't mention existentially
436 -- bound tyvars (typechecker checks for that) so no need for
437 -- the deleteListFromNameSet part
438 = foldr (plusFV . get_field) emptyFVs fields
440 get other_con = emptyFVs
442 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
443 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
444 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
445 get_details (NewCon t _) = extractHsTyNames t
447 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
448 | otherwise = emptyFVs
450 get_bang (Banged t) = extractHsTyNames t
451 get_bang (Unbanged t) = extractHsTyNames t
452 get_bang (Unpacked t) = extractHsTyNames t
454 getGates source_fvs other_decl = emptyFVs
457 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
458 rather than a declaration.
461 getWiredInGates :: Name -> FreeVars
462 getWiredInGates name -- No classes are wired in
463 | is_id = getWiredInGates_s (namesOfType (idType the_id))
464 | isSynTyCon the_tycon = getWiredInGates_s
465 (delListFromNameSet (namesOfType ty) (map getName tyvars))
466 | otherwise = unitFV name
468 maybe_wired_in_id = maybeWiredInIdName name
469 is_id = maybeToBool maybe_wired_in_id
470 maybe_wired_in_tycon = maybeWiredInTyConName name
471 Just the_id = maybe_wired_in_id
472 Just the_tycon = maybe_wired_in_tycon
473 (tyvars,ty) = getSynTyConDefn the_tycon
475 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
479 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
480 getInstDeclGates other = emptyFVs
484 %*********************************************************
486 \subsection{Unused names}
488 %*********************************************************
491 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _) mentioned_names
493 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
495 -- Now, a use of C implies a use of T,
496 -- if C was brought into scope by T(..) or T(C)
497 really_used_names = used_names `unionNameSets`
498 mkNameSet [ availName avail
499 | sub_name <- nameSetToList used_names,
500 let avail = case lookupNameEnv avail_env sub_name of
502 Nothing -> WARN( True, text "reportUnusedName: not in avail_env" <+> ppr sub_name )
506 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
507 defined_but_not_used =
508 nameSetToList (defined_names `minusNameSet` really_used_names)
510 -- Filter out the ones only defined implicitly
511 bad_guys = filter reportableUnusedName defined_but_not_used
513 warnUnusedTopNames bad_guys
515 reportableUnusedName :: Name -> Bool
516 reportableUnusedName name
517 = explicitlyImported (getNameProvenance name)
519 explicitlyImported (LocalDef _ _) = True
520 -- Report unused defns of local vars
521 explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl
522 -- Report unused explicit imports
523 explicitlyImported other = False
524 -- Don't report others
526 rnStats :: [RenamedHsDecl] -> RnMG ()
528 | opt_D_dump_rn_trace ||
529 opt_D_dump_rn_stats ||
531 = getRnStats imp_decls `thenRn` \ msg ->
532 ioToRnM (printErrs msg) `thenRn_`
535 | otherwise = returnRn ()
540 %*********************************************************
542 \subsection{Statistics}
544 %*********************************************************
547 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
548 getRnStats imported_decls
549 = getIfacesRn `thenRn` \ ifaces ->
551 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
553 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
554 -- Data, newtype, and class decls are in the decls_fm
555 -- under multiple names; the tycon/class, and each
556 -- constructor/class op too.
557 -- The 'True' selects just the 'main' decl
558 not (isLocallyDefined (availName avail))
561 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
562 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
564 unslurped_insts = iInsts ifaces
565 inst_decls_unslurped = length (bagToList unslurped_insts)
566 inst_decls_read = id_sp + inst_decls_unslurped
569 [int n_mods <+> text "interfaces read",
570 hsep [ int cd_sp, text "class decls imported, out of",
571 int cd_rd, text "read"],
572 hsep [ int dd_sp, text "data decls imported, out of",
573 int dd_rd, text "read"],
574 hsep [ int nd_sp, text "newtype decls imported, out of",
575 int nd_rd, text "read"],
576 hsep [int sd_sp, text "type synonym decls imported, out of",
577 int sd_rd, text "read"],
578 hsep [int vd_sp, text "value signatures imported, out of",
579 int vd_rd, text "read"],
580 hsep [int id_sp, text "instance decls imported, out of",
581 int inst_decls_read, text "read"],
582 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
583 [d | TyClD d <- imported_decls, isClassDecl d]),
584 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
585 [d | TyClD d <- decls_read, isClassDecl d])]
587 returnRn (hcat [text "Renamer stats: ", stats])
597 tycl_decls = [d | TyClD d <- decls]
598 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
600 val_decls = length [() | SigD _ <- decls]
601 inst_decls = length [() | InstD _ <- decls]