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(..), isDynamic,
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,
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 main_name = availName avail
269 new_decls_map = foldl add_decl decls_map
270 [ (name, (version, avail, name==main_name, (mod, decl')))
271 | name <- sys_bndrs ++ availNames avail]
272 add_decl decls_map (name, stuff)
273 = WARN( name `elemNameEnv` decls_map, ppr name )
274 addToNameEnv decls_map name stuff
276 returnRn new_decls_map
279 -- newImportedBinder puts into the cache the binder with the
280 -- module information set correctly. When the decl is later renamed,
281 -- the binding site will thereby get the correct module.
282 new_name rdr_name loc = newImportedBinder mod rdr_name
285 If a signature decl is being loaded, and optIgnoreIfacePragmas is on,
286 we toss away unfolding information.
288 Also, if the signature is loaded from a module we're importing from source,
289 we do the same. This is to avoid situations when compiling a pair of mutually
290 recursive modules, peering at unfolding info in the interface file of the other,
291 e.g., you compile A, it looks at B's interface file and may as a result change
292 its interface file. Hence, B is recompiled, maybe changing its interface file,
293 which will the unfolding info used in A to become invalid. Simple way out is to
294 just ignore unfolding info.
296 [Jan 99: I junked the second test above. If we're importing from an hi-boot
297 file there isn't going to *be* any pragma info. Maybe the above comment
298 dates from a time where we picked up a .hi file first if it existed?]
301 SigD (IfaceSig name tp ls loc) | opt_IgnoreIfacePragmas
302 -> SigD (IfaceSig name tp [] loc)
305 loadInstDecl :: Module
308 -> RnM d (Bag GatedDecl)
309 loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
311 -- Find out what type constructors and classes are "gates" for the
312 -- instance declaration. If all these "gates" are slurped in then
313 -- we should slurp the instance decl too.
315 -- We *don't* want to count names in the context part as gates, though.
317 -- instance Foo a => Baz (T a) where ...
319 -- Here the gates are Baz and T, but *not* Foo.
321 munged_inst_ty = removeContext inst_ty
322 free_names = extractHsTyRdrNames munged_inst_ty
324 setModuleRn (moduleName mod) $
325 mapRn mkImportedGlobalFromRdrName free_names `thenRn` \ gate_names ->
326 returnRn ((mkNameSet gate_names, (mod, InstD decl)) `consBag` insts)
329 -- In interface files, the instance decls now look like
330 -- forall a. Foo a -> Baz (T a)
331 -- so we have to strip off function argument types as well
332 -- as the bit before the '=>' (which is always empty in interface files)
333 removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
334 removeContext ty = removeFuns ty
336 removeFuns (MonoFunTy _ ty) = removeFuns ty
340 loadRule :: Module -> Bag GatedDecl
341 -> RdrNameRuleDecl -> RnM d (Bag GatedDecl)
342 -- "Gate" the rule simply by whether the rule variable is
343 -- needed. We can refine this later.
344 loadRule mod rules decl@(IfaceRuleDecl var body src_loc)
345 = setModuleRn (moduleName mod) $
346 mkImportedGlobalFromRdrName var `thenRn` \ var_name ->
347 returnRn ((unitNameSet var_name, (mod, RuleD decl)) `consBag` rules)
349 -- SUP: TEMPORARY HACK, ignoring module deprecations for now
350 loadDeprec :: Module -> DeprecationEnv -> RdrNameDeprecation -> RnM d DeprecationEnv
351 loadDeprec mod deprec_env (Deprecation (IEModuleContents _) txt)
352 = traceRn (text "module deprecation not yet implemented:" <+> ppr mod <> colon <+> ppr txt) `thenRn_`
354 loadDeprec mod deprec_env (Deprecation ie txt)
355 = setModuleRn (moduleName mod) $
356 mapRn mkImportedGlobalFromRdrName (namesFromIE ie) `thenRn` \ names ->
357 traceRn (text "loaded deprecation(s) for" <+> hcat (punctuate comma (map ppr names)) <> colon <+> ppr txt) `thenRn_`
358 returnRn (extendNameEnv deprec_env (zip names (repeat txt)))
360 namesFromIE :: IE a -> [a]
361 namesFromIE (IEVar n ) = [n]
362 namesFromIE (IEThingAbs n ) = [n]
363 namesFromIE (IEThingAll n ) = [n]
364 namesFromIE (IEThingWith n ns) = n:ns
365 namesFromIE (IEModuleContents _ ) = []
369 %********************************************************
371 \subsection{Loading usage information}
373 %********************************************************
376 checkUpToDate :: ModuleName -> RnMG Bool -- True <=> no need to recompile
377 checkUpToDate mod_name
378 = getIfacesRn `thenRn` \ ifaces ->
379 findAndReadIface doc_str mod_name
381 (error "checkUpToDate") `thenRn` \ (_, read_result) ->
383 -- CHECK WHETHER WE HAVE IT ALREADY
385 Nothing -> -- Old interface file not found, so we'd better bail out
386 traceRn (sep [ptext SLIT("Didnt find old iface"),
387 pprModuleName mod_name]) `thenRn_`
391 -> -- Found it, so now check it
392 checkModUsage (pi_usages iface)
394 -- Only look in current directory, with suffix .hi
395 doc_str = sep [ptext SLIT("need usage info from"), pprModuleName mod_name]
397 checkModUsage [] = returnRn True -- Yes! Everything is up to date!
399 checkModUsage ((mod_name, old_mod_vers, _, _, Specifically []) : rest)
400 -- If CurrentModule.hi contains
402 -- then that simply records that Foo lies below CurrentModule in the
403 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
404 -- In this case we don't even want to open Foo's interface.
405 = traceRn (ptext SLIT("Nothing used from:") <+> ppr mod_name) `thenRn_`
406 checkModUsage rest -- This one's ok, so check the rest
408 checkModUsage ((mod_name, old_mod_vers, _, _, whats_imported) : rest)
409 = loadInterface doc_str mod_name ImportBySystem `thenRn` \ (mod, ifaces) ->
411 maybe_mod_vers = case lookupFM (iImpModInfo ifaces) mod_name of
412 Just (version, _, _, Just (_, _)) -> Just version
415 case maybe_mod_vers of {
416 Nothing -> -- If we can't find a version number for the old module then
417 -- bail out saying things aren't up to date
418 traceRn (sep [ptext SLIT("Can't find version number for module"),
419 pprModuleName mod_name])
420 `thenRn_` returnRn False ;
424 -- If the module version hasn't changed, just move on
425 if new_mod_vers == old_mod_vers then
426 traceRn (sep [ptext SLIT("Module version unchanged:"), pprModuleName mod_name])
427 `thenRn_` checkModUsage rest
429 traceRn (sep [ptext SLIT("Module version has changed:"), pprModuleName mod_name])
431 -- Module version changed, so check entities inside
433 -- If the usage info wants to say "I imported everything from this module"
434 -- it does so by making whats_imported equal to Everything
435 -- In that case, we must recompile
436 case whats_imported of {
437 Everything -> traceRn (ptext SLIT("...and I needed the whole module")) `thenRn_`
438 returnRn False; -- Bale out
440 Specifically old_local_vers ->
442 -- Non-empty usage list, so check item by item
443 checkEntityUsage mod_name (iDecls ifaces) old_local_vers `thenRn` \ up_to_date ->
445 traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_`
446 checkModUsage rest -- This one's ok, so check the rest
448 returnRn False -- This one failed, so just bail out now
451 doc_str = sep [ptext SLIT("need version info for"), pprModuleName mod_name]
454 checkEntityUsage mod decls []
455 = returnRn True -- Yes! All up to date!
457 checkEntityUsage mod decls ((occ_name,old_vers) : rest)
458 = mkImportedGlobalName mod occ_name `thenRn` \ name ->
459 case lookupNameEnv decls name of
461 Nothing -> -- We used it before, but it ain't there now
462 traceRn (sep [ptext SLIT("No longer exported:"), ppr name])
463 `thenRn_` returnRn False
465 Just (new_vers,_,_,_) -- It's there, but is it up to date?
466 | new_vers == old_vers
467 -- Up to date, so check the rest
468 -> checkEntityUsage mod decls rest
471 -- Out of date, so bale out
472 -> traceRn (sep [ptext SLIT("Out of date:"), ppr name]) `thenRn_`
477 %*********************************************************
479 \subsection{Getting in a declaration}
481 %*********************************************************
484 importDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
485 -- Returns Nothing for
488 -- (c) already slurped
494 = getSlurped `thenRn` \ already_slurped ->
495 if name `elemNameSet` already_slurped then
496 returnRn Nothing -- Already dealt with
498 if isLocallyDefined name then -- Don't bring in decls from
499 -- the renamed module's own interface file
500 addWarnRn (importDeclWarn name) `thenRn_`
503 getNonWiredInDecl name
507 getNonWiredInDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
508 getNonWiredInDecl needed_name
509 = traceRn doc_str `thenRn_`
510 loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
511 case lookupNameEnv (iDecls ifaces) needed_name of
513 Just (version,avail,_,decl)
514 -> recordSlurp (Just version) avail `thenRn_`
517 Nothing -- Can happen legitimately for "Optional" occurrences
518 -> addErrRn (getDeclErr needed_name) `thenRn_`
521 doc_str = ptext SLIT("need decl for") <+> ppr needed_name
524 @getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
525 It behaves exactly as if the wired in decl were actually in an interface file.
528 \item if the wired-in name is a data type constructor or a data constructor,
529 it brings in the type constructor and all the data constructors; and
530 marks as ``occurrences'' any free vars of the data con.
532 \item similarly for synonum type constructor
534 \item if the wired-in name is another wired-in Id, it marks as ``occurrences''
535 the free vars of the Id's type.
537 \item it loads the interface file for the wired-in thing for the
538 sole purpose of making sure that its instance declarations are available
540 All this is necessary so that we know all types that are ``in play'', so
541 that we know just what instances to bring into scope.
546 %*********************************************************
548 \subsection{Getting what a module exports}
550 %*********************************************************
552 @getInterfaceExports@ is called only for directly-imported modules.
555 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
556 getInterfaceExports mod_name from
557 = loadInterface doc_str mod_name from `thenRn` \ (mod, ifaces) ->
558 case lookupFM (iImpModInfo ifaces) mod_name of
559 Nothing -> -- Not there; it must be that the interface file wasn't found;
560 -- the error will have been reported already.
561 -- (Actually loadInterface should put the empty export env in there
562 -- anyway, but this does no harm.)
565 Just (_, _, _, Just (mod, avails)) -> returnRn (mod, avails)
567 doc_str = sep [pprModuleName mod_name, ptext SLIT("is directly imported")]
571 %*********************************************************
573 \subsection{Instance declarations are handled specially}
575 %*********************************************************
578 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
579 getImportedInstDecls gates
580 = -- First, load any orphan-instance modules that aren't aready loaded
581 -- Orphan-instance modules are recorded in the module dependecnies
582 getIfacesRn `thenRn` \ ifaces ->
585 [mod | (mod, (_, True, _, Nothing)) <- fmToList (iImpModInfo ifaces)]
587 loadOrphanModules orphan_mods `thenRn_`
589 -- Now we're ready to grab the instance declarations
590 -- Find the un-gated ones and return them,
591 -- removing them from the bag kept in Ifaces
592 getIfacesRn `thenRn` \ ifaces ->
594 (decls, new_insts) = selectGated gates (iInsts ifaces)
596 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
598 traceRn (sep [text "getImportedInstDecls:",
599 nest 4 (fsep (map ppr gate_list)),
600 text "Slurped" <+> int (length decls) <+> text "instance declarations",
601 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
604 gate_list = nameSetToList gates
606 load_home gate | isLocallyDefined gate
609 = loadHomeInterface (ppr gate <+> text "is an instance gate") gate `thenRn_`
612 ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
614 HsForAllTy _ _ tau -> ppr tau
617 getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
619 | opt_IgnoreIfacePragmas = returnRn []
621 = getIfacesRn `thenRn` \ ifaces ->
623 gates = iSlurp ifaces -- Anything at all that's been slurped
624 (decls, new_rules) = selectGated gates (iRules ifaces)
626 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
627 traceRn (sep [text "getImportedRules:",
628 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
631 selectGated gates decl_bag
632 -- Select only those decls whose gates are *all* in 'gates'
634 | opt_NoPruneDecls -- Just to try the effect of not gating at all
635 = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
639 = foldrBag select ([], emptyBag) decl_bag
641 select (reqd, decl) (yes, no)
642 | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
643 | otherwise = (yes, (reqd,decl) `consBag` no)
645 lookupFixity :: Name -> RnMS Fixity
647 | isLocallyDefined name
648 = getFixityEnv `thenRn` \ local_fix_env ->
649 case lookupNameEnv local_fix_env name of
650 Just (FixitySig _ fix _) -> returnRn fix
651 Nothing -> returnRn defaultFixity
653 | otherwise -- Imported
654 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
655 -- and consulting the Ifaces that comes back from that, because the interface
656 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
657 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
658 -- right away (after all, it's possible that nothing from B will be used).
659 -- When we come across a use of 'f', we need to know its fixity, and it's then,
660 -- and only then, that we load B.hi. That is what's happening here.
661 = loadHomeInterface doc name `thenRn` \ ifaces ->
662 case lookupNameEnv (iFixes ifaces) name of
663 Just (FixitySig _ fix _) -> returnRn fix
664 Nothing -> returnRn defaultFixity
666 doc = ptext SLIT("Checking fixity for") <+> ppr name
670 %*********************************************************
672 \subsection{Keeping track of what we've slurped, and version numbers}
674 %*********************************************************
676 getImportVersions figures out what the ``usage information'' for this
677 moudule is; that is, what it must record in its interface file as the
678 things it uses. It records:
681 \item anything reachable from its body code
682 \item any module exported with a @module Foo@.
685 Why the latter? Because if @Foo@ changes then this module's export list
686 will change, so we must recompile this module at least as far as
687 making a new interface file --- but in practice that means complete
692 module A( f, g ) where | module B( f ) where
693 import B( f ) | f = h 3
697 Should we record @B.f@ in @A@'s usages? In fact we don't. Certainly,
698 if anything about @B.f@ changes than anyone who imports @A@ should be
699 recompiled; they'll get an early exit if they don't use @B.f@.
700 However, even if @B.f@ doesn't change at all, @B.h@ may do so, and
701 this change may not be reflected in @f@'s version number. So there
702 are two things going on when compiling module @A@:
705 \item Are @A.o@ and @A.hi@ correct? Then we can bale out early.
706 \item Should modules that import @A@ be recompiled?
709 For (1) it is slightly harmful to record @B.f@ in @A@'s usages,
710 because a change in @B.f@'s version will provoke full recompilation of
711 @A@, producing an identical @A.o@, and @A.hi@ differing only in its
712 usage-version of @B.f@ (and this usage-version info isn't used by any
715 For (2), because of the tricky @B.h@ question above, we ensure that
716 @A.hi@ is touched (even if identical to its previous version) if A's
717 recompilation was triggered by an imported @.hi@ file date change.
718 Given that, there's no need to record @B.f@ in @A@'s usages.
720 On the other hand, if @A@ exports @module B@, then we {\em do} count
721 @module B@ among @A@'s usages, because we must recompile @A@ to ensure
722 that @A.hi@ changes appropriately.
724 HOWEVER, we *do* record the usage
726 in A.hi, to record the fact that A does import B. This is used to decide
727 to look to look for B.hi rather than B.hi-boot when compiling a module that
728 imports A. This line says that A imports B, but uses nothing in it.
729 So we'll get an early bale-out when compiling A if B's version changes.
732 getImportVersions :: ModuleName -- Name of this module
733 -> ExportEnv -- Info about exports
734 -> RnMG (VersionInfo Name) -- Version info for these names
736 getImportVersions this_mod (ExportEnv export_avails _ export_all_mods)
737 = getIfacesRn `thenRn` \ ifaces ->
739 mod_map = iImpModInfo ifaces
740 imp_names = iVSlurp ifaces
742 -- mv_map groups together all the things imported from a particular module.
743 mv_map :: FiniteMap ModuleName [(Name,Version)]
744 mv_map = foldr add_mv emptyFM imp_names
746 -- Build the result list by adding info for each module.
747 -- For (a) a library module, we don't record it at all unless it contains orphans
748 -- (We must never lose track of orphans.)
750 -- (b) a source-imported module, don't record the dependency at all
752 -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
753 -- *all* the module's dependencies other than the loop-breakers. We use
754 -- this info in findAndReadInterface to decide whether to look for a .hi file or
757 -- This means we won't track version changes, or orphans, from .hi-boot files.
758 -- The former is potentially rather bad news. It could be fixed by recording
759 -- whether something is a boot file along with the usage info for it, but
760 -- I can't be bothered just now.
762 mk_version_info mod_name (version, has_orphans, is_boot, contents) so_far
764 go_for_it exports = (mod_name, version, has_orphans, is_boot, exports)
768 Nothing -> -- We didn't even open the interface
769 -- This happens when a module, Foo, that we explicitly imported has
770 -- 'import Baz' in its interface file, recording that Baz is below
771 -- Foo in the module dependency hierarchy. We want to propagate this
772 -- information. The Nothing says that we didn't even open the interface
773 -- file but we must still propagate the dependeny info.
774 go_for_it (Specifically [])
776 Just (mod, _) -- We did open the interface
777 | is_lib_module && not has_orphans
780 | is_lib_module -- Record the module but not detailed
781 || mod_name `elem` export_all_mods -- version information for the imports
782 -> go_for_it Everything
785 -> case lookupFM mv_map mod_name of
786 Just whats_imported -> go_for_it (Specifically whats_imported)
787 Nothing -> go_for_it (Specifically [])
788 -- This happens if you have
790 -- but don't actually *use* anything from Foo
791 -- In which case record an empty dependency list
793 is_lib_module = isLibModule mod
796 -- A module shouldn't load its own interface
797 -- This seems like a convenient place to check
798 WARN( maybeToBool (lookupFM mod_map this_mod),
799 ptext SLIT("Wierd:") <+> ppr this_mod <+> ptext SLIT("loads its own interface") )
801 returnRn (foldFM mk_version_info [] mod_map)
803 add_mv v@(name, version) mv_map
804 = addToFM_C add_item mv_map mod [v]
806 mod = moduleName (nameModule name)
807 add_item vs _ = (v:vs)
812 = getIfacesRn `thenRn` \ ifaces ->
813 returnRn (iSlurp ifaces)
815 recordSlurp maybe_version avail
816 = getIfacesRn `thenRn` \ ifaces@(Ifaces { iSlurp = slurped_names,
817 iVSlurp = imp_names }) ->
819 new_slurped_names = addAvailToNameSet slurped_names avail
821 new_imp_names = case maybe_version of
822 Just version -> (availName avail, version) : imp_names
825 setIfacesRn (ifaces { iSlurp = new_slurped_names,
826 iVSlurp = new_imp_names })
830 %*********************************************************
832 \subsection{Getting binders out of a declaration}
834 %*********************************************************
836 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
837 It's used for both source code (from @availsFromDecl@) and interface files
840 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
841 are handled by the sourc-code specific stuff in @RnNames@.
844 getDeclBinders :: (RdrName -> SrcLoc -> RnM d Name) -- New-name function
846 -> RnM d (Maybe AvailInfo)
848 getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ src_loc))
849 = new_name tycon src_loc `thenRn` \ tycon_name ->
850 getConFieldNames new_name condecls `thenRn` \ sub_names ->
851 returnRn (Just (AvailTC tycon_name (tycon_name : nub sub_names)))
852 -- The "nub" is because getConFieldNames can legitimately return duplicates,
853 -- when a record declaration has the same field in multiple constructors
855 getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc))
856 = new_name tycon src_loc `thenRn` \ tycon_name ->
857 returnRn (Just (AvailTC tycon_name [tycon_name]))
859 getDeclBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ _ _ _ src_loc))
860 = new_name cname src_loc `thenRn` \ class_name ->
862 -- Record the names for the class ops
864 -- just want class-op sigs
865 op_sigs = filter isClassOpSig sigs
867 mapRn (getClassOpNames new_name) op_sigs `thenRn` \ sub_names ->
869 returnRn (Just (AvailTC class_name (class_name : sub_names)))
871 getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc))
872 = new_name var src_loc `thenRn` \ var_name ->
873 returnRn (Just (Avail var_name))
875 getDeclBinders new_name (FixD _) = returnRn Nothing
877 -- foreign declarations
878 getDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
879 | binds_haskell_name kind dyn
880 = new_name nm loc `thenRn` \ name ->
881 returnRn (Just (Avail name))
883 | otherwise -- a foreign export
884 = lookupImplicitOccRn nm `thenRn_`
887 getDeclBinders new_name (DefD _) = returnRn Nothing
888 getDeclBinders new_name (InstD _) = returnRn Nothing
889 getDeclBinders new_name (RuleD _) = returnRn Nothing
891 binds_haskell_name (FoImport _) _ = True
892 binds_haskell_name FoLabel _ = True
893 binds_haskell_name FoExport ext_nm = isDynamic ext_nm
896 getConFieldNames new_name (ConDecl con _ _ (RecCon fielddecls) src_loc : rest)
897 = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs ->
898 getConFieldNames new_name rest `thenRn` \ ns ->
901 fields = concat (map fst fielddecls)
903 getConFieldNames new_name (ConDecl con _ _ condecl src_loc : rest)
904 = new_name con src_loc `thenRn` \ n ->
907 new_name f src_loc `thenRn` \ new_f ->
909 _ -> returnRn [n]) `thenRn` \ nn ->
910 getConFieldNames new_name rest `thenRn` \ ns ->
913 getConFieldNames new_name [] = returnRn []
915 getClassOpNames new_name (ClassOpSig op _ _ _ src_loc) = new_name op src_loc
918 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
919 A the moment that's just the tycon and datacon that come with a class decl.
920 They aren't returned by @getDeclBinders@ because they aren't in scope;
921 but they {\em should} be put into the @DeclsMap@ of this module.
923 Note that this excludes the default-method names of a class decl,
924 and the dict fun of an instance decl, because both of these have
925 bindings of their own elsewhere.
928 getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ tname dname snames src_loc))
929 = new_name dname src_loc `thenRn` \ datacon_name ->
930 new_name tname src_loc `thenRn` \ tycon_name ->
931 sequenceRn [new_name n src_loc | n <- snames] `thenRn` \ scsel_names ->
932 returnRn (tycon_name : datacon_name : scsel_names)
934 getDeclSysBinders new_name other_decl
938 %*********************************************************
940 \subsection{Reading an interface file}
942 %*********************************************************
945 findAndReadIface :: SDoc -> ModuleName -> WhereFrom
946 -> Bool -- Only relevant for SystemImport
947 -- True <=> Look for a .hi file
948 -- False <=> Look for .hi-boot file unless there's
949 -- a library .hi file
950 -> RnM d (Bool, Maybe (Module, ParsedIface))
951 -- Bool is True if the interface actually read was a .hi-boot one
952 -- Nothing <=> file not found, or unreadable, or illegible
953 -- Just x <=> successfully found and parsed
955 findAndReadIface doc_str mod_name from hi_file
956 = traceRn trace_msg `thenRn_`
957 -- we keep two maps for interface files,
958 -- one for 'normal' ones, the other for .hi-boot files,
959 -- hence the need to signal which kind we're interested.
961 getHiMaps `thenRn` \ hi_maps ->
963 case find_path from hi_maps of
965 (hi_boot, Just (fpath, mod)) -> traceRn (ptext SLIT("...reading from") <+> text fpath)
967 readIface mod fpath `thenRn` \ result ->
968 returnRn (hi_boot, result)
969 (hi_boot, Nothing) -> traceRn (ptext SLIT("...not found")) `thenRn_`
970 returnRn (hi_boot, Nothing)
972 find_path ImportByUser (hi_map, _) = (False, lookupFM hi_map mod_name)
973 find_path ImportByUserSource (_, hiboot_map) = (True, lookupFM hiboot_map mod_name)
975 find_path ImportBySystem (hi_map, hiboot_map)
977 = -- If the module we seek is in our dependent set,
978 -- Look for a .hi file
979 (False, lookupFM hi_map mod_name)
982 -- Check if there's a library module of that name
983 -- If not, look for an hi-boot file
984 = case lookupFM hi_map mod_name of
985 stuff@(Just (_, mod)) | isLibModule mod -> (False, stuff)
986 other -> (True, lookupFM hiboot_map mod_name)
988 trace_msg = sep [hsep [ptext SLIT("Reading"),
990 ptext SLIT("interface for"),
991 pprModuleName mod_name <> semi],
992 nest 4 (ptext SLIT("reason:") <+> doc_str)]
995 @readIface@ tries just the one file.
998 readIface :: Module -> String -> RnM d (Maybe (Module, ParsedIface))
999 -- Nothing <=> file not found, or unreadable, or illegible
1000 -- Just x <=> successfully found and parsed
1001 readIface the_mod file_path
1002 = ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
1005 case parseIface contents
1006 PState{ bol = 0#, atbol = 1#,
1009 loc = mkSrcLoc (mkFastString file_path) 1 } of
1010 POk _ (PIface mod_nm iface) ->
1011 warnCheckRn (mod_nm == moduleName the_mod)
1012 (hiModuleNameMismatchWarn the_mod mod_nm) `thenRn_`
1013 returnRn (Just (the_mod, iface))
1015 PFailed err -> failWithRn Nothing err
1016 other -> failWithRn Nothing (ptext SLIT("Unrecognisable interface file"))
1017 -- This last case can happen if the interface file is (say) empty
1018 -- in which case the parser thinks it looks like an IdInfo or
1019 -- something like that. Just an artefact of the fact that the
1020 -- parser is used for several purposes at once.
1023 | isDoesNotExistError err -> returnRn Nothing
1024 | otherwise -> failWithRn Nothing (cannaeReadFile file_path err)
1027 %*********************************************************
1031 %*********************************************************
1034 noIfaceErr filename boot_file
1035 = hsep [ptext SLIT("Could not find valid"), boot,
1036 ptext SLIT("interface file"), quotes (pprModule filename)]
1038 boot | boot_file = ptext SLIT("[boot]")
1041 cannaeReadFile file err
1042 = hcat [ptext SLIT("Failed in reading file: "),
1044 ptext SLIT("; error="),
1048 = ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name)
1050 getDeclWarn name loc
1051 = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),
1052 ptext SLIT("desired at") <+> ppr loc]
1056 "Compiler tried to import decl from interface file with same name as module."),
1058 "(possible cause: module name clashes with interface file already in scope.)")
1060 hsep [ptext SLIT("name:"), quotes (ppr name)]
1062 warnRedundantSourceImport mod_name
1063 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
1064 <+> quotes (pprModuleName mod_name)
1066 hiModuleNameMismatchWarn :: Module -> ModuleName -> Message
1067 hiModuleNameMismatchWarn requested_mod mod_nm =
1068 hsep [ ptext SLIT("Something is amiss; requested module name")
1069 , pprModule requested_mod
1070 , ptext SLIT("differs from name found in the interface file ")
1071 , pprModuleName mod_nm