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` \ (decls1, needed1, inst_gates) ->
245 -- Now we can get the instance decls
246 slurpInstDecls decls1 needed1 inst_gates `thenRn` \ (decls2, needed2) ->
248 -- And finally get everything else
249 closeDecls decls2 needed2
251 -------------------------------------------------------
252 slurpSourceRefs :: NameSet -- Variables defined in source
253 -> FreeVars -- Variables referenced in source
254 -> RnMG ([RenamedHsDecl],
255 FreeVars, -- Un-satisfied needs
257 -- The declaration (and hence home module) of each gate has
258 -- already been loaded
260 slurpSourceRefs source_binders source_fvs
261 = go [] -- Accumulating decls
262 emptyFVs -- Unsatisfied needs
263 source_fvs -- Accumulating gates
264 (nameSetToList source_fvs) -- Gates whose defn hasn't been loaded yet
266 go decls fvs gates []
267 = returnRn (decls, fvs, gates)
269 go decls fvs gates (wanted_name:refs)
270 | isWiredInName wanted_name
271 = load_home wanted_name `thenRn_`
272 go decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
275 = importDecl wanted_name `thenRn` \ maybe_decl ->
277 -- No declaration... (already slurped, or local)
278 Nothing -> go decls fvs gates refs
279 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
280 go (new_decl : decls)
282 (gates `plusFV` getGates source_fvs new_decl)
285 -- When we find a wired-in name we must load its
286 -- home module so that we find any instance decls therein
288 | name `elemNameSet` source_binders = returnRn ()
289 -- When compiling the prelude, a wired-in thing may
290 -- be defined in this module, in which case we don't
291 -- want to load its home module!
292 -- Using 'isLocallyDefined' doesn't work because some of
293 -- the free variables returned are simply 'listTyCon_Name',
294 -- with a system provenance. We could look them up every time
295 -- but that seems a waste.
296 | otherwise = loadHomeInterface doc name `thenRn_`
299 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
302 @slurpInstDecls@ imports appropriate instance decls.
303 It has to incorporate a loop, because consider
305 instance Foo a => Baz (Maybe a) where ...
307 It may be that @Baz@ and @Maybe@ are used in the source module,
308 but not @Foo@; so we need to chase @Foo@ too.
311 slurpInstDecls decls needed gates
312 = go decls needed gates gates
314 go decls needed all_gates new_gates
315 | isEmptyFVs new_gates
316 = returnRn (decls, needed)
319 = getImportedInstDecls all_gates `thenRn` \ inst_decls ->
320 rnInstDecls decls needed emptyFVs inst_decls `thenRn` \ (decls1, needed1, new_gates) ->
321 go decls1 needed1 (all_gates `plusFV` new_gates) new_gates
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)
333 -------------------------------------------------------
334 -- closeDecls keeps going until the free-var set is empty
335 closeDecls decls needed
336 | not (isEmptyFVs needed)
337 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
338 closeDecls decls1 needed1
341 = getImportedRules `thenRn` \ rule_decls ->
343 [] -> returnRn decls -- No new rules, so we are done
344 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
345 closeDecls decls1 needed1
348 -------------------------------------------------------
349 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
350 -> [(Module, RdrNameHsDecl)]
351 -> RnM d ([RenamedHsDecl], FreeVars)
352 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
353 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
354 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
356 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
359 -------------------------------------------------------
360 -- Augment decls with any decls needed by needed.
361 -- Return also free vars of the new decls (only)
362 slurpDecls decls needed
363 = go decls emptyFVs (nameSetToList needed)
365 go decls fvs [] = returnRn (decls, fvs)
366 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
369 -------------------------------------------------------
370 slurpDecl decls fvs wanted_name
371 = importDecl wanted_name `thenRn` \ maybe_decl ->
373 -- No declaration... (wired in thing)
374 Nothing -> returnRn (decls, fvs)
376 -- Found a declaration... rename it
377 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
378 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
382 %*********************************************************
384 \subsection{Extracting the `gates'}
386 %*********************************************************
388 When we import a declaration like
390 data T = T1 Wibble | T2 Wobble
392 we don't want to treat @Wibble@ and @Wobble@ as gates
393 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
394 If only @T@ is mentioned
395 we want only @T@ to be a gate;
396 that way we don't suck in useless instance
397 decls for (say) @Eq Wibble@, when they can't possibly be useful.
399 @getGates@ takes a newly imported (and renamed) decl, and the free
400 vars of the source program, and extracts from the decl the gate names.
403 getGates source_fvs (SigD (IfaceSig _ ty _ _))
404 = extractHsTyNames ty
406 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs sigs _ _ _ _ _ _))
407 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
408 (map getTyVarName tvs)
409 `addOneToNameSet` cls
411 get (ClassOpSig n _ ty _)
412 | n `elemNameSet` source_fvs = extractHsTyNames ty
413 | otherwise = emptyFVs
415 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
416 = delListFromNameSet (extractHsTyNames ty)
417 (map getTyVarName tvs)
418 -- A type synonym type constructor isn't a "gate" for instance decls
420 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
421 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
422 (map getTyVarName tvs)
423 `addOneToNameSet` tycon
425 get (ConDecl n tvs ctxt details _)
426 | n `elemNameSet` source_fvs
427 -- If the constructor is method, get fvs from all its fields
428 = delListFromNameSet (get_details details `plusFV`
429 extractHsCtxtTyNames ctxt)
430 (map getTyVarName tvs)
431 get (ConDecl n tvs ctxt (RecCon fields) _)
432 -- Even if the constructor isn't mentioned, the fields
433 -- might be, as selectors. They can't mention existentially
434 -- bound tyvars (typechecker checks for that) so no need for
435 -- the deleteListFromNameSet part
436 = foldr (plusFV . get_field) emptyFVs fields
438 get other_con = emptyFVs
440 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
441 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
442 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
443 get_details (NewCon t _) = extractHsTyNames t
445 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
446 | otherwise = emptyFVs
448 get_bang (Banged t) = extractHsTyNames t
449 get_bang (Unbanged t) = extractHsTyNames t
450 get_bang (Unpacked t) = extractHsTyNames t
452 getGates source_fvs other_decl = emptyFVs
455 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
456 rather than a declaration.
459 getWiredInGates :: Name -> FreeVars
460 getWiredInGates name -- No classes are wired in
461 | is_id = getWiredInGates_s (namesOfType (idType the_id))
462 | isSynTyCon the_tycon = getWiredInGates_s
463 (delListFromNameSet (namesOfType ty) (map getName tyvars))
464 | otherwise = unitFV name
466 maybe_wired_in_id = maybeWiredInIdName name
467 is_id = maybeToBool maybe_wired_in_id
468 maybe_wired_in_tycon = maybeWiredInTyConName name
469 Just the_id = maybe_wired_in_id
470 Just the_tycon = maybe_wired_in_tycon
471 (tyvars,ty) = getSynTyConDefn the_tycon
473 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
477 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
478 getInstDeclGates other = emptyFVs
482 %*********************************************************
484 \subsection{Unused names}
486 %*********************************************************
489 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _) mentioned_names
491 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
493 -- Now, a use of C implies a use of T,
494 -- if C was brought into scope by T(..) or T(C)
495 really_used_names = used_names `unionNameSets`
496 mkNameSet [ availName avail
497 | sub_name <- nameSetToList used_names,
498 let avail = case lookupNameEnv avail_env sub_name of
500 Nothing -> WARN( True, text "reportUnusedName: not in avail_env" <+> ppr sub_name )
504 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
505 defined_but_not_used =
506 nameSetToList (defined_names `minusNameSet` really_used_names)
508 -- Filter out the ones only defined implicitly
509 bad_guys = filter reportableUnusedName defined_but_not_used
511 warnUnusedTopNames bad_guys
513 reportableUnusedName :: Name -> Bool
514 reportableUnusedName name
515 = explicitlyImported (getNameProvenance name)
517 explicitlyImported (LocalDef _ _) = True
518 -- Report unused defns of local vars
519 explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl
520 -- Report unused explicit imports
521 explicitlyImported other = False
522 -- Don't report others
524 rnStats :: [RenamedHsDecl] -> RnMG ()
526 | opt_D_dump_rn_trace ||
527 opt_D_dump_rn_stats ||
529 = getRnStats imp_decls `thenRn` \ msg ->
530 ioToRnM (printErrs msg) `thenRn_`
533 | otherwise = returnRn ()
538 %*********************************************************
540 \subsection{Statistics}
542 %*********************************************************
545 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
546 getRnStats imported_decls
547 = getIfacesRn `thenRn` \ ifaces ->
549 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
551 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
552 -- Data, newtype, and class decls are in the decls_fm
553 -- under multiple names; the tycon/class, and each
554 -- constructor/class op too.
555 -- The 'True' selects just the 'main' decl
556 not (isLocallyDefined (availName avail))
559 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
560 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
562 unslurped_insts = iInsts ifaces
563 inst_decls_unslurped = length (bagToList unslurped_insts)
564 inst_decls_read = id_sp + inst_decls_unslurped
567 [int n_mods <+> text "interfaces read",
568 hsep [ int cd_sp, text "class decls imported, out of",
569 int cd_rd, text "read"],
570 hsep [ int dd_sp, text "data decls imported, out of",
571 int dd_rd, text "read"],
572 hsep [ int nd_sp, text "newtype decls imported, out of",
573 int nd_rd, text "read"],
574 hsep [int sd_sp, text "type synonym decls imported, out of",
575 int sd_rd, text "read"],
576 hsep [int vd_sp, text "value signatures imported, out of",
577 int vd_rd, text "read"],
578 hsep [int id_sp, text "instance decls imported, out of",
579 int inst_decls_read, text "read"],
580 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
581 [d | TyClD d <- imported_decls, isClassDecl d]),
582 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
583 [d | TyClD d <- decls_read, isClassDecl d])]
585 returnRn (hcat [text "Renamer stats: ", stats])
595 tycl_decls = [d | TyClD d <- decls]
596 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
598 val_decls = length [() | SigD _ <- decls]
599 inst_decls = length [() | InstD _ <- decls]