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
27 import RnEnv ( availName, availNames, availsToNameSet,
28 warnUnusedTopNames, mapFvRn,
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,
35 getNameProvenance, occNameUserString,
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 )
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 Util ( equivClasses )
55 import Maybes ( maybeToBool )
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, rn_errs_bag, rn_warns_bag) ->
79 doIfSet (not (isEmptyBag rn_warns_bag))
80 (printErrs (pprBagOfWarnings rn_warns_bag)) >>
82 -- Check for errors; exit if so
83 doIfSet (not (isEmptyBag rn_errs_bag))
84 (printErrs (pprBagOfErrors rn_errs_bag) >>
88 -- Dump output, if any
89 (case maybe_rn_stuff of
91 Just results@(_, rn_mod, _, _, _)
92 -> dumpIfSet opt_D_dump_rn "Renamer:"
102 rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
103 = -- FIND THE GLOBAL NAME ENVIRONMENT
104 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
106 -- CHECK FOR EARLY EXIT
107 if not (maybeToBool maybe_stuff) then
108 -- Everything is up to date; no need to recompile further
113 Just (export_env, gbl_env, fixity_env, global_avail_env) = maybe_stuff
117 initRnMS gbl_env fixity_env SourceMode (
118 rnSourceDecls local_decls
119 ) `thenRn` \ (rn_local_decls, source_fvs) ->
121 -- SLURP IN ALL THE NEEDED DECLARATIONS
123 real_source_fvs = implicitFVs mod_name `plusFV` source_fvs
124 -- It's important to do the "plus" this way round, so that
125 -- when compiling the prelude, locally-defined (), Bool, etc
126 -- override the implicit ones.
128 slurpImpDecls real_source_fvs `thenRn` \ rn_imp_decls ->
130 -- EXIT IF ERRORS FOUND
131 checkErrsRn `thenRn` \ no_errs_so_far ->
132 if not no_errs_so_far then
133 -- Found errors already, so exit now
138 -- GENERATE THE VERSION/USAGE INFO
139 getImportVersions mod_name exports `thenRn` \ my_usages ->
140 getNameSupplyRn `thenRn` \ name_supply ->
142 -- REPORT UNUSED NAMES
143 reportUnusedNames gbl_env global_avail_env
147 -- RETURN THE RENAMED MODULE
149 has_orphans = any isOrphanDecl rn_local_decls
150 direct_import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
151 rn_all_decls = rn_imp_decls ++ rn_local_decls
152 renamed_module = HsModule mod_name vers
153 trashed_exports trashed_imports
157 rnStats rn_imp_decls `thenRn_`
158 returnRn (Just (mkThisModule mod_name,
160 (has_orphans, my_usages, export_env),
164 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
165 trashed_imports = {-trace "rnSource:trashed_imports"-} []
168 @implicitFVs@ forces the renamer to slurp in some things which aren't
169 mentioned explicitly, but which might be needed by the type checker.
173 = implicit_main `plusFV`
174 mkNameSet default_tys `plusFV`
175 mkNameSet thinAirIdNames
177 -- Add occurrences for Int, Double, and (), because they
178 -- are the types to which ambigious type variables may be defaulted by
179 -- the type checker; so they won't always appear explicitly.
180 -- [The () one is a GHC extension for defaulting CCall results.]
181 -- ALSO: funTyCon, since it occurs implicitly everywhere!
182 -- (we don't want to be bothered with making funTyCon a
183 -- free var at every function application!)
184 default_tys = [getName intTyCon, getName doubleTyCon,
185 getName unitTyCon, getName funTyCon, getName boolTyCon]
187 -- Add occurrences for IO or PrimIO
188 implicit_main | mod_name == mAIN_Name
189 || mod_name == pREL_MAIN_Name = unitFV ioTyCon_NAME
190 | otherwise = emptyFVs
194 isOrphanDecl (InstD (InstDecl inst_ty _ _ _ _))
195 = not (foldNameSet ((||) . isLocallyDefined) False (extractHsTyNames inst_ty))
196 isOrphanDecl (RuleD (RuleDecl _ _ _ lhs _ _))
199 check (HsVar v) = not (isLocallyDefined v)
200 check (HsApp f a) = check f && check a
202 isOrphanDecl other = False
206 %*********************************************************
208 \subsection{Slurping declarations}
210 %*********************************************************
213 -------------------------------------------------------
214 slurpImpDecls source_fvs
215 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
217 -- The current slurped-set records all local things
218 getSlurped `thenRn` \ source_binders ->
219 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls1, needed1, inst_gates) ->
221 -- Now we can get the instance decls
222 slurpInstDecls decls1 needed1 inst_gates `thenRn` \ (decls2, needed2) ->
224 -- And finally get everything else
225 closeDecls decls2 needed2
227 -------------------------------------------------------
228 slurpSourceRefs :: NameSet -- Variables defined in source
229 -> FreeVars -- Variables referenced in source
230 -> RnMG ([RenamedHsDecl],
231 FreeVars, -- Un-satisfied needs
233 -- The declaration (and hence home module) of each gate has
234 -- already been loaded
236 slurpSourceRefs source_binders source_fvs
237 = go [] -- Accumulating decls
238 emptyFVs -- Unsatisfied needs
239 source_fvs -- Accumulating gates
240 (nameSetToList source_fvs) -- Gates whose defn hasn't been loaded yet
242 go decls fvs gates []
243 = returnRn (decls, fvs, gates)
245 go decls fvs gates (wanted_name:refs)
246 | isWiredInName wanted_name
247 = load_home wanted_name `thenRn_`
248 go decls fvs (gates `plusFV` getWiredInGates wanted_name) refs
251 = importDecl wanted_name `thenRn` \ maybe_decl ->
253 -- No declaration... (already slurped, or local)
254 Nothing -> go decls fvs gates refs
255 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
257 new_gates = getGates source_fvs new_decl
259 go (new_decl : decls)
261 (gates `plusFV` new_gates)
262 (nameSetToList new_gates ++ refs)
264 -- When we find a wired-in name we must load its
265 -- home module so that we find any instance decls therein
267 | name `elemNameSet` source_binders = returnRn ()
268 -- When compiling the prelude, a wired-in thing may
269 -- be defined in this module, in which case we don't
270 -- want to load its home module!
271 -- Using 'isLocallyDefined' doesn't work because some of
272 -- the free variables returned are simply 'listTyCon_Name',
273 -- with a system provenance. We could look them up every time
274 -- but that seems a waste.
275 | otherwise = loadHomeInterface doc name `thenRn_`
278 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
280 -------------------------------------------------------
281 -- slurpInstDecls imports appropriate instance decls.
282 -- It has to incorporate a loop, because consider
283 -- instance Foo a => Baz (Maybe a) where ...
284 -- It may be that Baz and Maybe are used in the source module,
285 -- but not Foo; so we need to chase Foo too.
287 slurpInstDecls decls needed gates
289 = returnRn (decls, needed)
292 = getImportedInstDecls gates `thenRn` \ inst_decls ->
293 rnInstDecls decls needed emptyFVs inst_decls `thenRn` \ (decls1, needed1, gates1) ->
294 slurpInstDecls decls1 needed1 gates1
296 rnInstDecls decls fvs gates []
297 = returnRn (decls, fvs, gates)
298 rnInstDecls decls fvs gates (d:ds)
299 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
300 rnInstDecls (new_decl:decls)
302 (gates `plusFV` getInstDeclGates new_decl)
306 -------------------------------------------------------
307 -- closeDecls keeps going until the free-var set is empty
308 closeDecls decls needed
309 | not (isEmptyFVs needed)
310 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
311 closeDecls decls1 needed1
314 = getImportedRules `thenRn` \ rule_decls ->
316 [] -> returnRn decls -- No new rules, so we are done
317 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
318 closeDecls decls1 needed1
321 -------------------------------------------------------
322 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
323 -> [(Module, RdrNameHsDecl)]
324 -> RnM d ([RenamedHsDecl], FreeVars)
325 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
326 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
327 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
329 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
332 -------------------------------------------------------
333 -- Augment decls with any decls needed by needed.
334 -- Return also free vars of the new decls (only)
335 slurpDecls decls needed
336 = go decls emptyFVs (nameSetToList needed)
338 go decls fvs [] = returnRn (decls, fvs)
339 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
342 -------------------------------------------------------
343 slurpDecl decls fvs wanted_name
344 = importDecl wanted_name `thenRn` \ maybe_decl ->
346 -- No declaration... (wired in thing)
347 Nothing -> returnRn (decls, fvs)
349 -- Found a declaration... rename it
350 Just decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
351 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
355 %*********************************************************
357 \subsection{Extracting the 'gates'}
359 %*********************************************************
361 When we import a declaration like
363 data T = T1 Wibble | T2 Wobble
365 we don't want to treat Wibble and Wobble as gates *unless* T1, T2
366 respectively are mentioned by the user program. If only T is mentioned
367 we want only T to be a gate; that way we don't suck in useless instance
368 decls for (say) Eq Wibble, when they can't possibly be useful.
370 @getGates@ takes a newly imported (and renamed) decl, and the free
371 vars of the source program, and extracts from the decl the gate names.
374 getGates source_fvs (SigD (IfaceSig _ ty _ _))
375 = extractHsTyNames ty
377 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs sigs _ _ _ _ _ _))
378 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
379 (map getTyVarName tvs)
380 `addOneToNameSet` cls
382 get (ClassOpSig n _ ty _)
383 | n `elemNameSet` source_fvs = extractHsTyNames ty
384 | otherwise = emptyFVs
386 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
387 = delListFromNameSet (extractHsTyNames ty)
388 (map getTyVarName tvs)
389 -- A type synonym type constructor isn't a "gate" for instance decls
391 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _))
392 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
393 (map getTyVarName tvs)
394 `addOneToNameSet` tycon
396 get (ConDecl n tvs ctxt details _)
397 | n `elemNameSet` source_fvs
398 -- If the constructor is method, get fvs from all its fields
399 = delListFromNameSet (get_details details `plusFV`
400 extractHsCtxtTyNames ctxt)
401 (map getTyVarName tvs)
402 get (ConDecl n tvs ctxt (RecCon fields) _)
403 -- Even if the constructor isn't mentioned, the fields
404 -- might be, as selectors. They can't mention existentially
405 -- bound tyvars (typechecker checks for that) so no need for
406 -- the deleteListFromNameSet part
407 = foldr (plusFV . get_field) emptyFVs fields
409 get other_con = emptyFVs
411 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
412 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
413 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
414 get_details (NewCon t _) = extractHsTyNames t
416 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
417 | otherwise = emptyFVs
419 get_bang (Banged t) = extractHsTyNames t
420 get_bang (Unbanged t) = extractHsTyNames t
421 get_bang (Unpacked t) = extractHsTyNames t
423 getGates source_fvs other_decl = emptyFVs
426 getWiredInGates is just like getGates, but it sees a wired-in Name
427 rather than a declaration.
430 getWiredInGates :: Name -> FreeVars
431 getWiredInGates name -- No classes are wired in
432 | is_id = getWiredInGates_s (namesOfType (idType the_id))
433 | isSynTyCon the_tycon = getWiredInGates_s (delListFromNameSet (namesOfType ty) (map getName tyvars))
434 | otherwise = unitFV name
436 maybe_wired_in_id = maybeWiredInIdName name
437 is_id = maybeToBool maybe_wired_in_id
438 maybe_wired_in_tycon = maybeWiredInTyConName name
439 Just the_id = maybe_wired_in_id
440 Just the_tycon = maybe_wired_in_tycon
441 (tyvars,ty) = getSynTyConDefn the_tycon
443 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
447 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
448 getInstDeclGates other = emptyFVs
452 %*********************************************************
454 \subsection{Unused names}
456 %*********************************************************
459 reportUnusedNames gbl_env avail_env (ExportEnv export_avails _) mentioned_names
460 | not (opt_WarnUnusedBinds || opt_WarnUnusedImports)
465 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
467 -- Now, a use of C implies a use of T,
468 -- if C was brought into scope by T(..) or T(C)
469 really_used_names = used_names `unionNameSets`
470 mkNameSet [ availName avail
471 | sub_name <- nameSetToList used_names,
472 let avail = case lookupNameEnv avail_env sub_name of
474 Nothing -> pprTrace "r.u.n" (ppr sub_name) $
478 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
479 defined_but_not_used = nameSetToList (defined_names `minusNameSet` really_used_names)
481 -- Filter out the ones only defined implicitly
482 bad_guys = filter reportableUnusedName defined_but_not_used
484 warnUnusedTopNames bad_guys `thenRn_`
487 reportableUnusedName :: Name -> Bool
488 reportableUnusedName name
489 = explicitlyImported (getNameProvenance name) &&
490 not (startsWithUnderscore (occNameUserString (nameOccName name)))
492 explicitlyImported (LocalDef _ _) = True -- Report unused defns of local vars
493 explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl -- Report unused explicit imports
494 explicitlyImported other = False -- Don't report others
496 -- Haskell 98 encourages compilers to suppress warnings about
497 -- unused names in a pattern if they start with "_".
498 startsWithUnderscore ('_' : _) = True -- Suppress warnings for names starting
499 startsWithUnderscore other = False -- with an underscore
501 rnStats :: [RenamedHsDecl] -> RnMG ()
503 | opt_D_dump_rn_trace ||
504 opt_D_dump_rn_stats ||
506 = getRnStats imp_decls `thenRn` \ msg ->
507 ioToRnM (printErrs msg) `thenRn_`
510 | otherwise = returnRn ()
515 %*********************************************************
517 \subsection{Statistics}
519 %*********************************************************
522 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
523 getRnStats imported_decls
524 = getIfacesRn `thenRn` \ ifaces ->
526 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
528 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
529 -- Data, newtype, and class decls are in the decls_fm
530 -- under multiple names; the tycon/class, and each
531 -- constructor/class op too.
532 -- The 'True' selects just the 'main' decl
533 not (isLocallyDefined (availName avail))
536 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
537 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
539 unslurped_insts = iInsts ifaces
540 inst_decls_unslurped = length (bagToList unslurped_insts)
541 inst_decls_read = id_sp + inst_decls_unslurped
544 [int n_mods <+> text "interfaces read",
545 hsep [ int cd_sp, text "class decls imported, out of",
546 int cd_rd, text "read"],
547 hsep [ int dd_sp, text "data decls imported, out of",
548 int dd_rd, text "read"],
549 hsep [ int nd_sp, text "newtype decls imported, out of",
550 int nd_rd, text "read"],
551 hsep [int sd_sp, text "type synonym decls imported, out of",
552 int sd_rd, text "read"],
553 hsep [int vd_sp, text "value signatures imported, out of",
554 int vd_rd, text "read"],
555 hsep [int id_sp, text "instance decls imported, out of",
556 int inst_decls_read, text "read"],
557 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
558 [d | TyClD d <- imported_decls, isClassDecl d]),
559 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
560 [d | TyClD d <- decls_read, isClassDecl d])]
562 returnRn (hcat [text "Renamer stats: ", stats])
572 tycl_decls = [d | TyClD d <- decls]
573 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
575 val_decls = length [() | SigD _ <- decls]
576 inst_decls = length [() | InstD _ <- decls]