2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnIfaces]{Cacheing and Renaming of Interfaces}
9 getImportedInstDecls, getImportedRules,
10 lookupFixity, loadHomeInterface,
11 importDecl, recordSlurp,
12 getImportVersions, getSlurped,
16 getDeclBinders, getDeclSysBinders,
17 removeContext -- removeContext probably belongs somewhere else
20 #include "HsVersions.h"
22 import CmdLineOpts ( opt_NoPruneDecls, opt_IgnoreIfacePragmas )
23 import HsSyn ( HsDecl(..), TyClDecl(..), InstDecl(..), IfaceSig(..),
24 HsType(..), ConDecl(..), IE(..), ConDetails(..), Sig(..),
25 ForeignDecl(..), ForKind(..), isDynamicExtName,
26 FixitySig(..), RuleDecl(..),
27 isClassOpSig, Deprecation(..)
29 import BasicTypes ( Version, NewOrData(..), defaultFixity )
30 import RdrHsSyn ( RdrNameHsDecl, RdrNameInstDecl, RdrNameTyClDecl, RdrNameRuleDecl,
31 extractHsTyRdrNames, RdrNameDeprecation
33 import RnEnv ( mkImportedGlobalName, newImportedBinder, mkImportedGlobalFromRdrName,
34 lookupOccRn, lookupImplicitOccRn,
36 availName, availNames, addAvailToNameSet, addSysAvails,
40 import RnHsSyn ( RenamedHsDecl, RenamedDeprecation )
41 import ParseIface ( parseIface, IfaceStuff(..) )
43 import FiniteMap ( FiniteMap, sizeFM, emptyFM, delFromFM, listToFM,
44 lookupFM, addToFM, addToFM_C, addListToFM,
45 fmToList, elemFM, foldFM
47 import Name ( Name {-instance NamedThing-},
48 nameModule, isLocallyDefined,
49 isWiredInName, nameUnique, NamedThing(..)
51 import Module ( Module, moduleString, pprModule,
52 mkVanillaModule, pprModuleName,
53 moduleUserString, moduleName, isLibModule,
54 ModuleName, WhereFrom(..),
56 import RdrName ( RdrName, rdrNameOcc )
59 import SrcLoc ( mkSrcLoc, SrcLoc )
60 import PrelMods ( pREL_GHC )
61 import PrelInfo ( cCallishTyKeys )
63 import Maybes ( MaybeErr(..), maybeToBool, orElse )
64 import ListSetOps ( unionLists )
66 import Unique ( Unique )
67 import StringBuffer ( StringBuffer, hGetStringBuffer )
68 import FastString ( mkFastString )
69 import ErrUtils ( Message )
73 import IO ( isDoesNotExistError )
78 %*********************************************************
80 \subsection{Loading a new interface file}
82 %*********************************************************
85 loadHomeInterface :: SDoc -> Name -> RnM d Ifaces
86 loadHomeInterface doc_str name
87 = loadInterface doc_str (moduleName (nameModule name)) ImportBySystem `thenRn` \ (_, ifaces) ->
90 loadOrphanModules :: [ModuleName] -> RnM d ()
91 loadOrphanModules mods
92 | null mods = returnRn ()
93 | otherwise = traceRn (text "Loading orphan modules:" <+> fsep (map pprModuleName mods)) `thenRn_`
94 mapRn_ load mods `thenRn_`
97 load mod = loadInterface (pprModuleName mod <+> ptext SLIT("is a orphan-instance module")) mod ImportBySystem
99 loadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d (Module, Ifaces)
100 loadInterface doc_str mod_name from
101 = getIfacesRn `thenRn` \ ifaces ->
103 mod_map = iImpModInfo ifaces
104 mod_info = lookupFM mod_map mod_name
105 below_me = case mod_info of
107 Just (_, _, is_boot, _) -> not is_boot
110 -- Issue a warning for a redundant {- SOURCE -} import
111 -- It's redundant if the moduld is in the iImpModInfo at all,
112 -- because we arrange to read all the ordinary imports before
113 -- any of the {- SOURCE -} imports
114 warnCheckRn (not (below_me && case from of {ImportByUserSource -> True; other -> False}))
115 (warnRedundantSourceImport mod_name) `thenRn_`
117 -- CHECK WHETHER WE HAVE IT ALREADY
119 Just (_, _, _, Just (load_mod, _))
120 -> -- We're read it already so don't re-read it
121 returnRn (load_mod, ifaces) ;
125 -- READ THE MODULE IN
126 findAndReadIface doc_str mod_name from below_me
127 `thenRn` \ (hi_boot_read, read_result) ->
128 case read_result of {
129 Nothing -> -- Not found, so add an empty export env to the Ifaces map
130 -- so that we don't look again
132 mod = mkVanillaModule mod_name
133 new_mod_map = addToFM mod_map mod_name (0, False, False, Just (mod, []))
134 new_ifaces = ifaces { iImpModInfo = new_mod_map }
136 setIfacesRn new_ifaces `thenRn_`
137 failWithRn (mod, new_ifaces) (noIfaceErr mod hi_boot_read) ;
142 -- LOAD IT INTO Ifaces
144 -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
145 --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
146 -- If we do loadExport first the wrong info gets into the cache (unless we
147 -- explicitly tag each export which seems a bit of a bore)
149 getModuleRn `thenRn` \ this_mod_nm ->
151 rd_decls = pi_decls iface
153 foldlRn (loadDecl mod) (iDecls ifaces) rd_decls `thenRn` \ new_decls ->
154 foldlRn (loadInstDecl mod) (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
155 (if opt_IgnoreIfacePragmas
156 then returnRn emptyBag
157 else foldlRn (loadRule mod) (iRules ifaces) (pi_rules iface)) `thenRn` \ new_rules ->
158 (if opt_IgnoreIfacePragmas
159 then returnRn emptyNameEnv
160 else foldlRn (loadDeprec mod) (iDeprecs ifaces) (pi_deprecs iface)) `thenRn` \ new_deprecs ->
161 foldlRn (loadFixDecl mod_name) (iFixes ifaces) rd_decls `thenRn` \ new_fixities ->
162 mapRn (loadExport this_mod_nm) (pi_exports iface) `thenRn` \ avails_s ->
164 -- For an explicit user import, add to mod_map info about
165 -- the things the imported module depends on, extracted
166 -- from its usage info.
167 mod_map1 = case from of
168 ImportByUser -> addModDeps mod mod_map (pi_usages iface)
171 -- Now add info about this module
172 mod_map2 = addToFM mod_map1 mod_name mod_details
173 mod_details = (pi_mod iface, pi_orphan iface, hi_boot_read, Just (mod, concat avails_s))
175 new_ifaces = ifaces { iImpModInfo = mod_map2,
177 iFixes = new_fixities,
180 iDeprecs = new_deprecs }
182 setIfacesRn new_ifaces `thenRn_`
183 returnRn (mod, new_ifaces)
186 addModDeps :: Module -> ImportedModuleInfo
187 -> [ImportVersion a] -> ImportedModuleInfo
188 addModDeps mod mod_deps new_deps
189 = foldr add mod_deps new_deps
191 is_lib = isLibModule mod -- Don't record dependencies when importing a library module
192 add (imp_mod, version, has_orphans, is_boot, _) deps
193 | is_lib && not has_orphans = deps
194 | otherwise = addToFM_C combine deps imp_mod (version, has_orphans, is_boot, Nothing)
195 -- Record dependencies for modules that are
196 -- either are dependent via a non-library module
197 -- or contain orphan rules or instance decls
199 -- Don't ditch a module that's already loaded
200 -- If it isn't loaded, and together the is_boot-ness
201 combine old@(_, _, _, Just _) new = old
202 combine old@(_, _, old_is_boot, Nothing)
203 new@(version, has_orphans, new_is_boot, _)
204 = (version, has_orphans, old_is_boot && new_is_boot, Nothing)
206 loadExport :: ModuleName -> ExportItem -> RnM d [AvailInfo]
207 loadExport this_mod (mod, entities)
208 | mod == this_mod = returnRn []
209 -- If the module exports anything defined in this module, just ignore it.
210 -- Reason: otherwise it looks as if there are two local definition sites
211 -- for the thing, and an error gets reported. Easiest thing is just to
212 -- filter them out up front. This situation only arises if a module
213 -- imports itself, or another module that imported it. (Necessarily,
214 -- this invoves a loop.) Consequence: if you say
219 -- module B( AType ) where
220 -- import {-# SOURCE #-} A( AType )
222 -- then you'll get a 'B does not export AType' message. A bit bogus
223 -- but it's a bogus thing to do!
226 = mapRn (load_entity mod) entities
228 new_name mod occ = mkImportedGlobalName mod occ
230 load_entity mod (Avail occ)
231 = new_name mod occ `thenRn` \ name ->
232 returnRn (Avail name)
233 load_entity mod (AvailTC occ occs)
234 = new_name mod occ `thenRn` \ name ->
235 mapRn (new_name mod) occs `thenRn` \ names ->
236 returnRn (AvailTC name names)
239 loadFixDecl :: ModuleName -> FixityEnv
240 -> (Version, RdrNameHsDecl)
242 loadFixDecl mod_name fixity_env (version, FixD sig@(FixitySig rdr_name fixity loc))
243 = -- Ignore the version; when the fixity changes the version of
244 -- its 'host' entity changes, so we don't need a separate version
245 -- number for fixities
246 mkImportedGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
248 new_fixity_env = addToNameEnv fixity_env name (FixitySig name fixity loc)
250 returnRn new_fixity_env
252 -- Ignore the other sorts of decl
253 loadFixDecl mod_name fixity_env other_decl = returnRn fixity_env
257 -> (Version, RdrNameHsDecl)
260 loadDecl mod decls_map (version, decl)
261 = getDeclBinders new_name decl `thenRn` \ maybe_avail ->
262 case maybe_avail of {
263 Nothing -> returnRn decls_map; -- No bindings
266 getDeclSysBinders new_name decl `thenRn` \ sys_bndrs ->
268 full_avail = addSysAvails avail sys_bndrs
269 -- Add the sys-binders to avail. When we import the decl,
270 -- it's full_avail that will get added to the 'already-slurped' set (iSlurp)
271 -- If we miss out sys-binders, we'll read the decl multiple times!
273 main_name = availName avail
274 new_decls_map = foldl add_decl decls_map
275 [ (name, (version, full_avail, name==main_name, (mod, decl')))
276 | name <- availNames full_avail]
277 add_decl decls_map (name, stuff)
278 = WARN( name `elemNameEnv` decls_map, ppr name )
279 addToNameEnv decls_map name stuff
281 returnRn new_decls_map
284 -- newImportedBinder puts into the cache the binder with the
285 -- module information set correctly. When the decl is later renamed,
286 -- the binding site will thereby get the correct module.
287 new_name rdr_name loc = newImportedBinder mod rdr_name
290 If a signature decl is being loaded, and optIgnoreIfacePragmas is on,
291 we toss away unfolding information.
293 Also, if the signature is loaded from a module we're importing from source,
294 we do the same. This is to avoid situations when compiling a pair of mutually
295 recursive modules, peering at unfolding info in the interface file of the other,
296 e.g., you compile A, it looks at B's interface file and may as a result change
297 its interface file. Hence, B is recompiled, maybe changing its interface file,
298 which will the unfolding info used in A to become invalid. Simple way out is to
299 just ignore unfolding info.
301 [Jan 99: I junked the second test above. If we're importing from an hi-boot
302 file there isn't going to *be* any pragma info. Maybe the above comment
303 dates from a time where we picked up a .hi file first if it existed?]
306 SigD (IfaceSig name tp ls loc) | opt_IgnoreIfacePragmas
307 -> SigD (IfaceSig name tp [] loc)
310 loadInstDecl :: Module
313 -> RnM d (Bag GatedDecl)
314 loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
316 -- Find out what type constructors and classes are "gates" for the
317 -- instance declaration. If all these "gates" are slurped in then
318 -- we should slurp the instance decl too.
320 -- We *don't* want to count names in the context part as gates, though.
322 -- instance Foo a => Baz (T a) where ...
324 -- Here the gates are Baz and T, but *not* Foo.
326 munged_inst_ty = removeContext inst_ty
327 free_names = extractHsTyRdrNames munged_inst_ty
329 setModuleRn (moduleName mod) $
330 mapRn mkImportedGlobalFromRdrName free_names `thenRn` \ gate_names ->
331 returnRn ((mkNameSet gate_names, (mod, InstD decl)) `consBag` insts)
334 -- In interface files, the instance decls now look like
335 -- forall a. Foo a -> Baz (T a)
336 -- so we have to strip off function argument types as well
337 -- as the bit before the '=>' (which is always empty in interface files)
338 removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
339 removeContext ty = removeFuns ty
341 removeFuns (MonoFunTy _ ty) = removeFuns ty
345 loadRule :: Module -> Bag GatedDecl
346 -> RdrNameRuleDecl -> RnM d (Bag GatedDecl)
347 -- "Gate" the rule simply by whether the rule variable is
348 -- needed. We can refine this later.
349 loadRule mod rules decl@(IfaceRuleDecl var body src_loc)
350 = setModuleRn (moduleName mod) $
351 mkImportedGlobalFromRdrName var `thenRn` \ var_name ->
352 returnRn ((unitNameSet var_name, (mod, RuleD decl)) `consBag` rules)
354 -- SUP: TEMPORARY HACK, ignoring module deprecations for now
355 loadDeprec :: Module -> DeprecationEnv -> RdrNameDeprecation -> RnM d DeprecationEnv
356 loadDeprec mod deprec_env (Deprecation (IEModuleContents _) txt)
357 = traceRn (text "module deprecation not yet implemented:" <+> ppr mod <> colon <+> ppr txt) `thenRn_`
359 loadDeprec mod deprec_env (Deprecation ie txt)
360 = setModuleRn (moduleName mod) $
361 mapRn mkImportedGlobalFromRdrName (namesFromIE ie) `thenRn` \ names ->
362 traceRn (text "loaded deprecation(s) for" <+> hcat (punctuate comma (map ppr names)) <> colon <+> ppr txt) `thenRn_`
363 returnRn (extendNameEnv deprec_env (zip names (repeat txt)))
365 namesFromIE :: IE a -> [a]
366 namesFromIE (IEVar n ) = [n]
367 namesFromIE (IEThingAbs n ) = [n]
368 namesFromIE (IEThingAll n ) = [n]
369 namesFromIE (IEThingWith n ns) = n:ns
370 namesFromIE (IEModuleContents _ ) = []
374 %********************************************************
376 \subsection{Loading usage information}
378 %********************************************************
381 checkUpToDate :: ModuleName -> RnMG Bool -- True <=> no need to recompile
382 checkUpToDate mod_name
383 = getIfacesRn `thenRn` \ ifaces ->
384 findAndReadIface doc_str mod_name
386 (error "checkUpToDate") `thenRn` \ (_, read_result) ->
388 -- CHECK WHETHER WE HAVE IT ALREADY
390 Nothing -> -- Old interface file not found, so we'd better bail out
391 traceRn (sep [ptext SLIT("Didnt find old iface"),
392 pprModuleName mod_name]) `thenRn_`
396 -> -- Found it, so now check it
397 checkModUsage (pi_usages iface)
399 -- Only look in current directory, with suffix .hi
400 doc_str = sep [ptext SLIT("need usage info from"), pprModuleName mod_name]
402 checkModUsage [] = returnRn True -- Yes! Everything is up to date!
404 checkModUsage ((mod_name, old_mod_vers, _, _, Specifically []) : rest)
405 -- If CurrentModule.hi contains
407 -- then that simply records that Foo lies below CurrentModule in the
408 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
409 -- In this case we don't even want to open Foo's interface.
410 = traceRn (ptext SLIT("Nothing used from:") <+> ppr mod_name) `thenRn_`
411 checkModUsage rest -- This one's ok, so check the rest
413 checkModUsage ((mod_name, old_mod_vers, _, _, whats_imported) : rest)
414 = loadInterface doc_str mod_name ImportBySystem `thenRn` \ (mod, ifaces) ->
416 maybe_mod_vers = case lookupFM (iImpModInfo ifaces) mod_name of
417 Just (version, _, _, Just (_, _)) -> Just version
420 case maybe_mod_vers of {
421 Nothing -> -- If we can't find a version number for the old module then
422 -- bail out saying things aren't up to date
423 traceRn (sep [ptext SLIT("Can't find version number for module"),
424 pprModuleName mod_name])
425 `thenRn_` returnRn False ;
429 -- If the module version hasn't changed, just move on
430 if new_mod_vers == old_mod_vers then
431 traceRn (sep [ptext SLIT("Module version unchanged:"), pprModuleName mod_name])
432 `thenRn_` checkModUsage rest
434 traceRn (sep [ptext SLIT("Module version has changed:"), pprModuleName mod_name])
436 -- Module version changed, so check entities inside
438 -- If the usage info wants to say "I imported everything from this module"
439 -- it does so by making whats_imported equal to Everything
440 -- In that case, we must recompile
441 case whats_imported of {
442 Everything -> traceRn (ptext SLIT("...and I needed the whole module")) `thenRn_`
443 returnRn False; -- Bale out
445 Specifically old_local_vers ->
447 -- Non-empty usage list, so check item by item
448 checkEntityUsage mod_name (iDecls ifaces) old_local_vers `thenRn` \ up_to_date ->
450 traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_`
451 checkModUsage rest -- This one's ok, so check the rest
453 returnRn False -- This one failed, so just bail out now
456 doc_str = sep [ptext SLIT("need version info for"), pprModuleName mod_name]
459 checkEntityUsage mod decls []
460 = returnRn True -- Yes! All up to date!
462 checkEntityUsage mod decls ((occ_name,old_vers) : rest)
463 = mkImportedGlobalName mod occ_name `thenRn` \ name ->
464 case lookupNameEnv decls name of
466 Nothing -> -- We used it before, but it ain't there now
467 traceRn (sep [ptext SLIT("No longer exported:"), ppr name])
468 `thenRn_` returnRn False
470 Just (new_vers,_,_,_) -- It's there, but is it up to date?
471 | new_vers == old_vers
472 -- Up to date, so check the rest
473 -> checkEntityUsage mod decls rest
476 -- Out of date, so bale out
477 -> traceRn (sep [ptext SLIT("Out of date:"), ppr name]) `thenRn_`
482 %*********************************************************
484 \subsection{Getting in a declaration}
486 %*********************************************************
489 importDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
490 -- Returns Nothing for
493 -- (c) already slurped
499 = getSlurped `thenRn` \ already_slurped ->
500 if name `elemNameSet` already_slurped then
501 returnRn Nothing -- Already dealt with
503 if isLocallyDefined name then -- Don't bring in decls from
504 -- the renamed module's own interface file
505 addWarnRn (importDeclWarn name) `thenRn_`
508 getNonWiredInDecl name
512 getNonWiredInDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
513 getNonWiredInDecl needed_name
514 = traceRn doc_str `thenRn_`
515 loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
516 case lookupNameEnv (iDecls ifaces) needed_name of
518 Just (version,avail,_,decl)
519 -> recordSlurp (Just version) avail `thenRn_`
522 Nothing -- Can happen legitimately for "Optional" occurrences
523 -> addErrRn (getDeclErr needed_name) `thenRn_`
526 doc_str = ptext SLIT("need decl for") <+> ppr needed_name
529 @getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
530 It behaves exactly as if the wired in decl were actually in an interface file.
533 \item if the wired-in name is a data type constructor or a data constructor,
534 it brings in the type constructor and all the data constructors; and
535 marks as ``occurrences'' any free vars of the data con.
537 \item similarly for synonum type constructor
539 \item if the wired-in name is another wired-in Id, it marks as ``occurrences''
540 the free vars of the Id's type.
542 \item it loads the interface file for the wired-in thing for the
543 sole purpose of making sure that its instance declarations are available
545 All this is necessary so that we know all types that are ``in play'', so
546 that we know just what instances to bring into scope.
551 %*********************************************************
553 \subsection{Getting what a module exports}
555 %*********************************************************
557 @getInterfaceExports@ is called only for directly-imported modules.
560 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
561 getInterfaceExports mod_name from
562 = loadInterface doc_str mod_name from `thenRn` \ (mod, ifaces) ->
563 case lookupFM (iImpModInfo ifaces) mod_name of
564 Nothing -> -- Not there; it must be that the interface file wasn't found;
565 -- the error will have been reported already.
566 -- (Actually loadInterface should put the empty export env in there
567 -- anyway, but this does no harm.)
570 Just (_, _, _, Just (mod, avails)) -> returnRn (mod, avails)
572 doc_str = sep [pprModuleName mod_name, ptext SLIT("is directly imported")]
576 %*********************************************************
578 \subsection{Instance declarations are handled specially}
580 %*********************************************************
583 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
584 getImportedInstDecls gates
585 = -- First, load any orphan-instance modules that aren't aready loaded
586 -- Orphan-instance modules are recorded in the module dependecnies
587 getIfacesRn `thenRn` \ ifaces ->
590 [mod | (mod, (_, True, _, Nothing)) <- fmToList (iImpModInfo ifaces)]
592 loadOrphanModules orphan_mods `thenRn_`
594 -- Now we're ready to grab the instance declarations
595 -- Find the un-gated ones and return them,
596 -- removing them from the bag kept in Ifaces
597 getIfacesRn `thenRn` \ ifaces ->
599 (decls, new_insts) = selectGated gates (iInsts ifaces)
601 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
603 traceRn (sep [text "getImportedInstDecls:",
604 nest 4 (fsep (map ppr gate_list)),
605 text "Slurped" <+> int (length decls) <+> text "instance declarations",
606 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
609 gate_list = nameSetToList gates
611 load_home gate | isLocallyDefined gate
614 = loadHomeInterface (ppr gate <+> text "is an instance gate") gate `thenRn_`
617 ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
619 HsForAllTy _ _ tau -> ppr tau
622 getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
624 | opt_IgnoreIfacePragmas = returnRn []
626 = getIfacesRn `thenRn` \ ifaces ->
628 gates = iSlurp ifaces -- Anything at all that's been slurped
629 (decls, new_rules) = selectGated gates (iRules ifaces)
631 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
632 traceRn (sep [text "getImportedRules:",
633 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
636 selectGated gates decl_bag
637 -- Select only those decls whose gates are *all* in 'gates'
639 | opt_NoPruneDecls -- Just to try the effect of not gating at all
640 = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
644 = foldrBag select ([], emptyBag) decl_bag
646 select (reqd, decl) (yes, no)
647 | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
648 | otherwise = (yes, (reqd,decl) `consBag` no)
650 lookupFixity :: Name -> RnMS Fixity
652 | isLocallyDefined name
653 = getFixityEnv `thenRn` \ local_fix_env ->
654 case lookupNameEnv local_fix_env name of
655 Just (FixitySig _ fix _) -> returnRn fix
656 Nothing -> returnRn defaultFixity
658 | otherwise -- Imported
659 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
660 -- and consulting the Ifaces that comes back from that, because the interface
661 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
662 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
663 -- right away (after all, it's possible that nothing from B will be used).
664 -- When we come across a use of 'f', we need to know its fixity, and it's then,
665 -- and only then, that we load B.hi. That is what's happening here.
666 = loadHomeInterface doc name `thenRn` \ ifaces ->
667 case lookupNameEnv (iFixes ifaces) name of
668 Just (FixitySig _ fix _) -> returnRn fix
669 Nothing -> returnRn defaultFixity
671 doc = ptext SLIT("Checking fixity for") <+> ppr name
675 %*********************************************************
677 \subsection{Keeping track of what we've slurped, and version numbers}
679 %*********************************************************
681 getImportVersions figures out what the ``usage information'' for this
682 moudule is; that is, what it must record in its interface file as the
683 things it uses. It records:
686 \item (a) anything reachable from its body code
687 \item (b) any module exported with a @module Foo@
688 \item (c) anything reachable from an exported item
691 Why (b)? Because if @Foo@ changes then this module's export list
692 will change, so we must recompile this module at least as far as
693 making a new interface file --- but in practice that means complete
696 Why (c)? Consider this:
698 module A( f, g ) where | module B( f ) where
699 import B( f ) | f = h 3
703 Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
704 @A@'s usages? Our idea is that we aren't going to touch A.hi if it is
705 *identical* to what it was before. If anything about @B.f@ changes
706 than anyone who imports @A@ should be recompiled in case they use
707 @B.f@ (they'll get an early exit if they don't). So, if anything
708 about @B.f@ changes we'd better make sure that something in A.hi
709 changes, and the convenient way to do that is to record the version
710 number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
711 complete recompiation of A, which is overkill but it's the only way to
712 write a new, slightly different, A.hi.
714 But the example is tricker. Even if @B.f@ doesn't change at all,
715 @B.h@ may do so, and this change may not be reflected in @f@'s version
716 number. But with -O, a module that imports A must be recompiled if
717 @B.h@ changes! So A must record a dependency on @B.h@. So we treat
718 the occurrence of @B.f@ in the export list *just as if* it were in the
719 code of A, and thereby haul in all the stuff reachable from it.
721 [NB: If B was compiled with -O, but A isn't, we should really *still*
722 haul in all the unfoldings for B, in case the module that imports A *is*
723 compiled with -O. I think this is the case.]
725 Even if B is used at all we get a usage line for B
726 import B <n> :: ... ;
727 in A.hi, to record the fact that A does import B. This is used to decide
728 to look to look for B.hi rather than B.hi-boot when compiling a module that
729 imports A. This line says that A imports B, but uses nothing in it.
730 So we'll get an early bale-out when compiling A if B's version changes.
733 getImportVersions :: ModuleName -- Name of this module
734 -> ExportEnv -- Info about exports
735 -> RnMG (VersionInfo Name) -- Version info for these names
737 getImportVersions this_mod (ExportEnv _ _ export_all_mods)
738 = getIfacesRn `thenRn` \ ifaces ->
740 mod_map = iImpModInfo ifaces
741 imp_names = iVSlurp ifaces
743 -- mv_map groups together all the things imported from a particular module.
744 mv_map :: FiniteMap ModuleName [(Name,Version)]
745 mv_map = foldr add_mv emptyFM imp_names
747 -- Build the result list by adding info for each module.
748 -- For (a) a library module, we don't record it at all unless it contains orphans
749 -- (We must never lose track of orphans.)
751 -- (b) a source-imported module, don't record the dependency at all
753 -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
754 -- *all* the module's dependencies other than the loop-breakers. We use
755 -- this info in findAndReadInterface to decide whether to look for a .hi file or
758 -- This means we won't track version changes, or orphans, from .hi-boot files.
759 -- The former is potentially rather bad news. It could be fixed by recording
760 -- whether something is a boot file along with the usage info for it, but
761 -- I can't be bothered just now.
763 mk_version_info mod_name (version, has_orphans, is_boot, contents) so_far
765 go_for_it exports = (mod_name, version, has_orphans, is_boot, exports)
769 Nothing -> -- We didn't even open the interface
770 -- This happens when a module, Foo, that we explicitly imported has
771 -- 'import Baz' in its interface file, recording that Baz is below
772 -- Foo in the module dependency hierarchy. We want to propagate this
773 -- information. The Nothing says that we didn't even open the interface
774 -- file but we must still propagate the dependeny info.
775 go_for_it (Specifically [])
777 Just (mod, _) -- We did open the interface
778 | is_lib_module && not has_orphans
781 | is_lib_module -- Record the module but not detailed
782 || mod_name `elem` export_all_mods -- version information for the imports
783 -> go_for_it Everything
786 -> case lookupFM mv_map mod_name of
787 Just whats_imported -> go_for_it (Specifically whats_imported)
788 Nothing -> go_for_it (Specifically [])
789 -- This happens if you have
791 -- but don't actually *use* anything from Foo
792 -- In which case record an empty dependency list
794 is_lib_module = isLibModule mod
797 -- A module shouldn't load its own interface
798 -- This seems like a convenient place to check
799 WARN( maybeToBool (lookupFM mod_map this_mod),
800 ptext SLIT("Wierd:") <+> ppr this_mod <+> ptext SLIT("loads its own interface") )
802 returnRn (foldFM mk_version_info [] mod_map)
804 add_mv v@(name, version) mv_map
805 = addToFM_C add_item mv_map mod [v]
807 mod = moduleName (nameModule name)
808 add_item vs _ = (v:vs)
813 = getIfacesRn `thenRn` \ ifaces ->
814 returnRn (iSlurp ifaces)
816 recordSlurp maybe_version avail
817 -- Nothing for locally defined names
818 -- Just version for imported names
819 = getIfacesRn `thenRn` \ ifaces@(Ifaces { iSlurp = slurped_names,
820 iVSlurp = imp_names }) ->
822 new_slurped_names = addAvailToNameSet slurped_names avail
824 new_imp_names = case maybe_version of
825 Just version -> (availName avail, version) : imp_names
828 setIfacesRn (ifaces { iSlurp = new_slurped_names,
829 iVSlurp = new_imp_names })
833 %*********************************************************
835 \subsection{Getting binders out of a declaration}
837 %*********************************************************
839 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
840 It's used for both source code (from @availsFromDecl@) and interface files
843 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
844 are handled by the sourc-code specific stuff in @RnNames@.
847 getDeclBinders :: (RdrName -> SrcLoc -> RnM d Name) -- New-name function
849 -> RnM d (Maybe AvailInfo)
851 getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ src_loc))
852 = new_name tycon src_loc `thenRn` \ tycon_name ->
853 getConFieldNames new_name condecls `thenRn` \ sub_names ->
854 returnRn (Just (AvailTC tycon_name (tycon_name : nub sub_names)))
855 -- The "nub" is because getConFieldNames can legitimately return duplicates,
856 -- when a record declaration has the same field in multiple constructors
858 getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc))
859 = new_name tycon src_loc `thenRn` \ tycon_name ->
860 returnRn (Just (AvailTC tycon_name [tycon_name]))
862 getDeclBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ _ _ _ _ src_loc))
863 = new_name cname src_loc `thenRn` \ class_name ->
865 -- Record the names for the class ops
867 -- just want class-op sigs
868 op_sigs = filter isClassOpSig sigs
870 mapRn (getClassOpNames new_name) op_sigs `thenRn` \ sub_names ->
872 returnRn (Just (AvailTC class_name (class_name : sub_names)))
874 getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc))
875 = new_name var src_loc `thenRn` \ var_name ->
876 returnRn (Just (Avail var_name))
878 getDeclBinders new_name (FixD _) = returnRn Nothing
880 -- foreign declarations
881 getDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
882 | binds_haskell_name kind dyn
883 = new_name nm loc `thenRn` \ name ->
884 returnRn (Just (Avail name))
886 | otherwise -- a foreign export
887 = lookupImplicitOccRn nm `thenRn_`
890 getDeclBinders new_name (DefD _) = returnRn Nothing
891 getDeclBinders new_name (InstD _) = returnRn Nothing
892 getDeclBinders new_name (RuleD _) = returnRn Nothing
894 binds_haskell_name (FoImport _) _ = True
895 binds_haskell_name FoLabel _ = True
896 binds_haskell_name FoExport ext_nm = isDynamicExtName ext_nm
899 getConFieldNames new_name (ConDecl con _ _ _ (RecCon fielddecls) src_loc : rest)
900 = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs ->
901 getConFieldNames new_name rest `thenRn` \ ns ->
904 fields = concat (map fst fielddecls)
906 getConFieldNames new_name (ConDecl con _ _ _ condecl src_loc : rest)
907 = new_name con src_loc `thenRn` \ n ->
910 new_name f src_loc `thenRn` \ new_f ->
912 _ -> returnRn [n]) `thenRn` \ nn ->
913 getConFieldNames new_name rest `thenRn` \ ns ->
916 getConFieldNames new_name [] = returnRn []
918 getClassOpNames new_name (ClassOpSig op _ _ _ src_loc) = new_name op src_loc
921 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
922 A the moment that's just the tycon and datacon that come with a class decl.
923 They aren't returned by @getDeclBinders@ because they aren't in scope;
924 but they {\em should} be put into the @DeclsMap@ of this module.
926 Note that this excludes the default-method names of a class decl,
927 and the dict fun of an instance decl, because both of these have
928 bindings of their own elsewhere.
931 getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ tname dname dwname snames src_loc))
932 = sequenceRn [new_name n src_loc | n <- (tname : dname : dwname : snames)]
934 getDeclSysBinders new_name (TyClD (TyData _ _ _ _ cons _ _ _))
935 = sequenceRn [new_name wkr_name src_loc | ConDecl _ wkr_name _ _ _ src_loc <- cons]
937 getDeclSysBinders new_name other_decl
941 %*********************************************************
943 \subsection{Reading an interface file}
945 %*********************************************************
948 findAndReadIface :: SDoc -> ModuleName -> WhereFrom
949 -> Bool -- Only relevant for SystemImport
950 -- True <=> Look for a .hi file
951 -- False <=> Look for .hi-boot file unless there's
952 -- a library .hi file
953 -> RnM d (Bool, Maybe (Module, ParsedIface))
954 -- Bool is True if the interface actually read was a .hi-boot one
955 -- Nothing <=> file not found, or unreadable, or illegible
956 -- Just x <=> successfully found and parsed
958 findAndReadIface doc_str mod_name from hi_file
959 = traceRn trace_msg `thenRn_`
960 -- we keep two maps for interface files,
961 -- one for 'normal' ones, the other for .hi-boot files,
962 -- hence the need to signal which kind we're interested.
964 getHiMaps `thenRn` \ hi_maps ->
966 case find_path from hi_maps of
968 (hi_boot, Just (fpath, mod)) -> traceRn (ptext SLIT("...reading from") <+> text fpath)
970 readIface mod fpath `thenRn` \ result ->
971 returnRn (hi_boot, result)
972 (hi_boot, Nothing) -> traceRn (ptext SLIT("...not found")) `thenRn_`
973 returnRn (hi_boot, Nothing)
975 find_path ImportByUser (hi_map, _) = (False, lookupFM hi_map mod_name)
976 find_path ImportByUserSource (_, hiboot_map) = (True, lookupFM hiboot_map mod_name)
978 find_path ImportBySystem (hi_map, hiboot_map)
980 = -- If the module we seek is in our dependent set,
981 -- Look for a .hi file
982 (False, lookupFM hi_map mod_name)
985 -- Check if there's a library module of that name
986 -- If not, look for an hi-boot file
987 = case lookupFM hi_map mod_name of
988 stuff@(Just (_, mod)) | isLibModule mod -> (False, stuff)
989 other -> (True, lookupFM hiboot_map mod_name)
991 trace_msg = sep [hsep [ptext SLIT("Reading"),
993 ptext SLIT("interface for"),
994 pprModuleName mod_name <> semi],
995 nest 4 (ptext SLIT("reason:") <+> doc_str)]
998 @readIface@ tries just the one file.
1001 readIface :: Module -> String -> RnM d (Maybe (Module, ParsedIface))
1002 -- Nothing <=> file not found, or unreadable, or illegible
1003 -- Just x <=> successfully found and parsed
1004 readIface the_mod file_path
1005 = ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
1008 case parseIface contents
1009 PState{ bol = 0#, atbol = 1#,
1012 loc = mkSrcLoc (mkFastString file_path) 1 } of
1013 POk _ (PIface mod_nm iface) ->
1014 warnCheckRn (mod_nm == moduleName the_mod)
1015 (hiModuleNameMismatchWarn the_mod mod_nm) `thenRn_`
1016 returnRn (Just (the_mod, iface))
1018 PFailed err -> failWithRn Nothing err
1019 other -> failWithRn Nothing (ptext SLIT("Unrecognisable interface file"))
1020 -- This last case can happen if the interface file is (say) empty
1021 -- in which case the parser thinks it looks like an IdInfo or
1022 -- something like that. Just an artefact of the fact that the
1023 -- parser is used for several purposes at once.
1026 | isDoesNotExistError err -> returnRn Nothing
1027 | otherwise -> failWithRn Nothing (cannaeReadFile file_path err)
1030 %*********************************************************
1034 %*********************************************************
1037 noIfaceErr filename boot_file
1038 = hsep [ptext SLIT("Could not find valid"), boot,
1039 ptext SLIT("interface file"), quotes (pprModule filename)]
1041 boot | boot_file = ptext SLIT("[boot]")
1044 cannaeReadFile file err
1045 = hcat [ptext SLIT("Failed in reading file: "),
1047 ptext SLIT("; error="),
1051 = ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name)
1053 getDeclWarn name loc
1054 = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),
1055 ptext SLIT("desired at") <+> ppr loc]
1059 "Compiler tried to import decl from interface file with same name as module."),
1061 "(possible cause: module name clashes with interface file already in scope.)")
1063 hsep [ptext SLIT("name:"), quotes (ppr name)]
1065 warnRedundantSourceImport mod_name
1066 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
1067 <+> quotes (pprModuleName mod_name)
1069 hiModuleNameMismatchWarn :: Module -> ModuleName -> Message
1070 hiModuleNameMismatchWarn requested_mod mod_nm =
1071 hsep [ ptext SLIT("Something is amiss; requested module name")
1072 , pprModule requested_mod
1073 , ptext SLIT("differs from name found in the interface file ")
1074 , pprModuleName mod_nm