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 in_map = maybeToBool mod_info
108 -- Issue a warning for a redundant {- SOURCE -} import
109 -- It's redundant if the moduld is in the iImpModInfo at all,
110 -- because we arrange to read all the ordinary imports before
111 -- any of the {- SOURCE -} imports
112 warnCheckRn (not (in_map && case from of {ImportByUserSource -> True; other -> False}))
113 (warnRedundantSourceImport mod_name) `thenRn_`
115 -- CHECK WHETHER WE HAVE IT ALREADY
117 Just (_, _, Just (load_mod, _, _))
118 -> -- We're read it already so don't re-read it
119 returnRn (load_mod, ifaces) ;
123 -- READ THE MODULE IN
124 findAndReadIface doc_str mod_name from in_map
125 `thenRn` \ (hi_boot_read, read_result) ->
126 case read_result of {
127 Nothing -> -- Not found, so add an empty export env to the Ifaces map
128 -- so that we don't look again
130 mod = mkVanillaModule mod_name
131 new_mod_map = addToFM mod_map mod_name (0, False, Just (mod, False, []))
132 new_ifaces = ifaces { iImpModInfo = new_mod_map }
134 setIfacesRn new_ifaces `thenRn_`
135 failWithRn (mod, new_ifaces) (noIfaceErr mod hi_boot_read) ;
140 -- LOAD IT INTO Ifaces
142 -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
143 --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
144 -- If we do loadExport first the wrong info gets into the cache (unless we
145 -- explicitly tag each export which seems a bit of a bore)
147 getModuleRn `thenRn` \ this_mod_nm ->
149 rd_decls = pi_decls iface
151 foldlRn (loadDecl mod) (iDecls ifaces) rd_decls `thenRn` \ new_decls ->
152 foldlRn (loadInstDecl mod) (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
153 (if opt_IgnoreIfacePragmas
154 then returnRn emptyBag
155 else foldlRn (loadRule mod) (iRules ifaces) (pi_rules iface)) `thenRn` \ new_rules ->
156 (if opt_IgnoreIfacePragmas
157 then returnRn emptyNameEnv
158 else foldlRn (loadDeprec mod) (iDeprecs ifaces) (pi_deprecs iface)) `thenRn` \ new_deprecs ->
159 foldlRn (loadFixDecl mod_name) (iFixes ifaces) rd_decls `thenRn` \ new_fixities ->
160 mapRn (loadExport this_mod_nm) (pi_exports iface) `thenRn` \ avails_s ->
162 -- For an explicit user import, add to mod_map info about
163 -- the things the imported module depends on, extracted
164 -- from its usage info.
165 mod_map1 = case from of
166 ImportByUser -> addModDeps mod mod_map (pi_usages iface)
169 -- Now add info about this module
170 mod_map2 = addToFM mod_map1 mod_name mod_details
171 mod_details = (pi_mod iface, pi_orphan iface, Just (mod, hi_boot_read, concat avails_s))
173 new_ifaces = ifaces { iImpModInfo = mod_map2,
175 iFixes = new_fixities,
178 iDeprecs = new_deprecs }
180 setIfacesRn new_ifaces `thenRn_`
181 returnRn (mod, new_ifaces)
184 addModDeps :: Module -> ImportedModuleInfo
185 -> [ImportVersion a] -> ImportedModuleInfo
186 addModDeps mod mod_deps new_deps
187 = foldr add mod_deps new_deps
189 is_lib = isLibModule mod -- Don't record dependencies when importing a library module
190 add (imp_mod, version, has_orphans, _) deps
191 | is_lib && not has_orphans = deps
192 | otherwise = addToFM_C combine deps imp_mod (version, has_orphans, Nothing)
193 -- Record dependencies for modules that are
194 -- either are dependent via a non-library module
195 -- or contain orphan rules or instance decls
197 -- Don't ditch a module that's already loaded!!
198 combine old@(_, _, Just _) new = old
199 combine old@(_, _, Nothing) new = new
201 loadExport :: ModuleName -> ExportItem -> RnM d [AvailInfo]
202 loadExport this_mod (mod, entities)
203 | mod == this_mod = returnRn []
204 -- If the module exports anything defined in this module, just ignore it.
205 -- Reason: otherwise it looks as if there are two local definition sites
206 -- for the thing, and an error gets reported. Easiest thing is just to
207 -- filter them out up front. This situation only arises if a module
208 -- imports itself, or another module that imported it. (Necessarily,
209 -- this invoves a loop.) Consequence: if you say
214 -- module B( AType ) where
215 -- import {-# SOURCE #-} A( AType )
217 -- then you'll get a 'B does not export AType' message. A bit bogus
218 -- but it's a bogus thing to do!
221 = mapRn (load_entity mod) entities
223 new_name mod occ = mkImportedGlobalName mod occ
225 load_entity mod (Avail occ)
226 = new_name mod occ `thenRn` \ name ->
227 returnRn (Avail name)
228 load_entity mod (AvailTC occ occs)
229 = new_name mod occ `thenRn` \ name ->
230 mapRn (new_name mod) occs `thenRn` \ names ->
231 returnRn (AvailTC name names)
234 loadFixDecl :: ModuleName -> FixityEnv
235 -> (Version, RdrNameHsDecl)
237 loadFixDecl mod_name fixity_env (version, FixD sig@(FixitySig rdr_name fixity loc))
238 = -- Ignore the version; when the fixity changes the version of
239 -- its 'host' entity changes, so we don't need a separate version
240 -- number for fixities
241 mkImportedGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
243 new_fixity_env = addToNameEnv fixity_env name (FixitySig name fixity loc)
245 returnRn new_fixity_env
247 -- Ignore the other sorts of decl
248 loadFixDecl mod_name fixity_env other_decl = returnRn fixity_env
252 -> (Version, RdrNameHsDecl)
255 loadDecl mod decls_map (version, decl)
256 = getDeclBinders new_name decl `thenRn` \ maybe_avail ->
257 case maybe_avail of {
258 Nothing -> returnRn decls_map; -- No bindings
261 getDeclSysBinders new_name decl `thenRn` \ sys_bndrs ->
263 main_name = availName avail
264 new_decls_map = foldl add_decl decls_map
265 [ (name, (version, avail, name==main_name, (mod, decl')))
266 | name <- sys_bndrs ++ availNames avail]
267 add_decl decls_map (name, stuff)
268 = WARN( name `elemNameEnv` decls_map, ppr name )
269 addToNameEnv decls_map name stuff
271 returnRn new_decls_map
274 -- newImportedBinder puts into the cache the binder with the
275 -- module information set correctly. When the decl is later renamed,
276 -- the binding site will thereby get the correct module.
277 new_name rdr_name loc = newImportedBinder mod rdr_name
280 If a signature decl is being loaded, and optIgnoreIfacePragmas is on,
281 we toss away unfolding information.
283 Also, if the signature is loaded from a module we're importing from source,
284 we do the same. This is to avoid situations when compiling a pair of mutually
285 recursive modules, peering at unfolding info in the interface file of the other,
286 e.g., you compile A, it looks at B's interface file and may as a result change
287 its interface file. Hence, B is recompiled, maybe changing its interface file,
288 which will the unfolding info used in A to become invalid. Simple way out is to
289 just ignore unfolding info.
291 [Jan 99: I junked the second test above. If we're importing from an hi-boot
292 file there isn't going to *be* any pragma info. Maybe the above comment
293 dates from a time where we picked up a .hi file first if it existed?]
296 SigD (IfaceSig name tp ls loc) | opt_IgnoreIfacePragmas
297 -> SigD (IfaceSig name tp [] loc)
300 loadInstDecl :: Module
303 -> RnM d (Bag GatedDecl)
304 loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
306 -- Find out what type constructors and classes are "gates" for the
307 -- instance declaration. If all these "gates" are slurped in then
308 -- we should slurp the instance decl too.
310 -- We *don't* want to count names in the context part as gates, though.
312 -- instance Foo a => Baz (T a) where ...
314 -- Here the gates are Baz and T, but *not* Foo.
316 munged_inst_ty = removeContext inst_ty
317 free_names = extractHsTyRdrNames munged_inst_ty
319 setModuleRn (moduleName mod) $
320 mapRn mkImportedGlobalFromRdrName free_names `thenRn` \ gate_names ->
321 returnRn ((mkNameSet gate_names, (mod, InstD decl)) `consBag` insts)
324 -- In interface files, the instance decls now look like
325 -- forall a. Foo a -> Baz (T a)
326 -- so we have to strip off function argument types as well
327 -- as the bit before the '=>' (which is always empty in interface files)
328 removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
329 removeContext ty = removeFuns ty
331 removeFuns (MonoFunTy _ ty) = removeFuns ty
335 loadRule :: Module -> Bag GatedDecl
336 -> RdrNameRuleDecl -> RnM d (Bag GatedDecl)
337 -- "Gate" the rule simply by whether the rule variable is
338 -- needed. We can refine this later.
339 loadRule mod rules decl@(IfaceRuleDecl var body src_loc)
340 = setModuleRn (moduleName mod) $
341 mkImportedGlobalFromRdrName var `thenRn` \ var_name ->
342 returnRn ((unitNameSet var_name, (mod, RuleD decl)) `consBag` rules)
344 -- SUP: TEMPORARY HACK, ignoring module deprecations and constructors for now
345 loadDeprec :: Module -> DeprecationEnv -> RdrNameDeprecation -> RnM d DeprecationEnv
346 loadDeprec mod deprec_env (Deprecation (IEModuleContents _) txt)
347 = traceRn (text "module deprecation not yet implemented:" <+> ppr mod <> colon <+> ppr txt) `thenRn_`
349 loadDeprec mod deprec_env (Deprecation (IEVar rdr_name) txt)
350 = setModuleRn (moduleName mod) $
351 mkImportedGlobalFromRdrName rdr_name `thenRn` \ name ->
352 traceRn (text "loaded deprecation for" <+> ppr name <> colon <+> ppr txt) `thenRn_`
353 returnRn (addToNameEnv deprec_env name txt)
357 %********************************************************
359 \subsection{Loading usage information}
361 %********************************************************
364 checkUpToDate :: ModuleName -> RnMG Bool -- True <=> no need to recompile
365 checkUpToDate mod_name
366 = getIfacesRn `thenRn` \ ifaces ->
367 findAndReadIface doc_str mod_name
369 (error "checkUpToDate") `thenRn` \ (_, read_result) ->
371 -- CHECK WHETHER WE HAVE IT ALREADY
373 Nothing -> -- Old interface file not found, so we'd better bail out
374 traceRn (sep [ptext SLIT("Didnt find old iface"),
375 pprModuleName mod_name]) `thenRn_`
379 -> -- Found it, so now check it
380 checkModUsage (pi_usages iface)
382 -- Only look in current directory, with suffix .hi
383 doc_str = sep [ptext SLIT("need usage info from"), pprModuleName mod_name]
385 checkModUsage [] = returnRn True -- Yes! Everything is up to date!
387 checkModUsage ((mod_name, old_mod_vers, _, Specifically []) : rest)
388 -- If CurrentModule.hi contains
390 -- then that simply records that Foo lies below CurrentModule in the
391 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
392 -- In this case we don't even want to open Foo's interface.
393 = traceRn (ptext SLIT("Nothing used from:") <+> ppr mod_name) `thenRn_`
394 checkModUsage rest -- This one's ok, so check the rest
396 checkModUsage ((mod_name, old_mod_vers, _, whats_imported) : rest)
397 = loadInterface doc_str mod_name ImportBySystem `thenRn` \ (mod, ifaces) ->
399 maybe_mod_vers = case lookupFM (iImpModInfo ifaces) mod_name of
400 Just (version, _, Just (_, _, _)) -> Just version
403 case maybe_mod_vers of {
404 Nothing -> -- If we can't find a version number for the old module then
405 -- bail out saying things aren't up to date
406 traceRn (sep [ptext SLIT("Can't find version number for module"),
407 pprModuleName mod_name])
408 `thenRn_` returnRn False ;
412 -- If the module version hasn't changed, just move on
413 if new_mod_vers == old_mod_vers then
414 traceRn (sep [ptext SLIT("Module version unchanged:"), pprModuleName mod_name])
415 `thenRn_` checkModUsage rest
417 traceRn (sep [ptext SLIT("Module version has changed:"), pprModuleName mod_name])
419 -- Module version changed, so check entities inside
421 -- If the usage info wants to say "I imported everything from this module"
422 -- it does so by making whats_imported equal to Everything
423 -- In that case, we must recompile
424 case whats_imported of {
425 Everything -> traceRn (ptext SLIT("...and I needed the whole module")) `thenRn_`
426 returnRn False; -- Bale out
428 Specifically old_local_vers ->
430 -- Non-empty usage list, so check item by item
431 checkEntityUsage mod_name (iDecls ifaces) old_local_vers `thenRn` \ up_to_date ->
433 traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_`
434 checkModUsage rest -- This one's ok, so check the rest
436 returnRn False -- This one failed, so just bail out now
439 doc_str = sep [ptext SLIT("need version info for"), pprModuleName mod_name]
442 checkEntityUsage mod decls []
443 = returnRn True -- Yes! All up to date!
445 checkEntityUsage mod decls ((occ_name,old_vers) : rest)
446 = mkImportedGlobalName mod occ_name `thenRn` \ name ->
447 case lookupNameEnv decls name of
449 Nothing -> -- We used it before, but it ain't there now
450 traceRn (sep [ptext SLIT("No longer exported:"), ppr name])
451 `thenRn_` returnRn False
453 Just (new_vers,_,_,_) -- It's there, but is it up to date?
454 | new_vers == old_vers
455 -- Up to date, so check the rest
456 -> checkEntityUsage mod decls rest
459 -- Out of date, so bale out
460 -> traceRn (sep [ptext SLIT("Out of date:"), ppr name]) `thenRn_`
465 %*********************************************************
467 \subsection{Getting in a declaration}
469 %*********************************************************
472 importDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
473 -- Returns Nothing for
476 -- (c) already slurped
482 = getSlurped `thenRn` \ already_slurped ->
483 if name `elemNameSet` already_slurped then
484 returnRn Nothing -- Already dealt with
486 if isLocallyDefined name then -- Don't bring in decls from
487 -- the renamed module's own interface file
488 addWarnRn (importDeclWarn name) `thenRn_`
491 getNonWiredInDecl name
495 getNonWiredInDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
496 getNonWiredInDecl needed_name
497 = traceRn doc_str `thenRn_`
498 loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
499 case lookupNameEnv (iDecls ifaces) needed_name of
501 Just (version,avail,_,decl)
502 -> recordSlurp (Just version) avail `thenRn_`
505 Nothing -- Can happen legitimately for "Optional" occurrences
506 -> addErrRn (getDeclErr needed_name) `thenRn_`
509 doc_str = ptext SLIT("need decl for") <+> ppr needed_name
512 @getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
513 It behaves exactly as if the wired in decl were actually in an interface file.
516 \item if the wired-in name is a data type constructor or a data constructor,
517 it brings in the type constructor and all the data constructors; and
518 marks as ``occurrences'' any free vars of the data con.
520 \item similarly for synonum type constructor
522 \item if the wired-in name is another wired-in Id, it marks as ``occurrences''
523 the free vars of the Id's type.
525 \item it loads the interface file for the wired-in thing for the
526 sole purpose of making sure that its instance declarations are available
528 All this is necessary so that we know all types that are ``in play'', so
529 that we know just what instances to bring into scope.
534 %*********************************************************
536 \subsection{Getting what a module exports}
538 %*********************************************************
540 @getInterfaceExports@ is called only for directly-imported modules.
543 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
544 getInterfaceExports mod_name from
545 = loadInterface doc_str mod_name from `thenRn` \ (mod, ifaces) ->
546 case lookupFM (iImpModInfo ifaces) mod_name of
547 Nothing -> -- Not there; it must be that the interface file wasn't found;
548 -- the error will have been reported already.
549 -- (Actually loadInterface should put the empty export env in there
550 -- anyway, but this does no harm.)
553 Just (_, _, Just (mod, _, avails)) -> returnRn (mod, avails)
555 doc_str = sep [pprModuleName mod_name, ptext SLIT("is directly imported")]
559 %*********************************************************
561 \subsection{Instance declarations are handled specially}
563 %*********************************************************
566 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
567 getImportedInstDecls gates
568 = -- First, load any orphan-instance modules that aren't aready loaded
569 -- Orphan-instance modules are recorded in the module dependecnies
570 getIfacesRn `thenRn` \ ifaces ->
573 [mod | (mod, (_, True, Nothing)) <- fmToList (iImpModInfo ifaces)]
575 loadOrphanModules orphan_mods `thenRn_`
577 -- Now we're ready to grab the instance declarations
578 -- Find the un-gated ones and return them,
579 -- removing them from the bag kept in Ifaces
580 getIfacesRn `thenRn` \ ifaces ->
582 (decls, new_insts) = selectGated gates (iInsts ifaces)
584 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
586 traceRn (sep [text "getImportedInstDecls:",
587 nest 4 (fsep (map ppr gate_list)),
588 text "Slurped" <+> int (length decls) <+> text "instance declarations",
589 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
592 gate_list = nameSetToList gates
594 load_home gate | isLocallyDefined gate
597 = loadHomeInterface (ppr gate <+> text "is an instance gate") gate `thenRn_`
600 ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
602 HsForAllTy _ _ tau -> ppr tau
605 getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
607 | opt_IgnoreIfacePragmas = returnRn []
609 = getIfacesRn `thenRn` \ ifaces ->
611 gates = iSlurp ifaces -- Anything at all that's been slurped
612 (decls, new_rules) = selectGated gates (iRules ifaces)
614 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
615 traceRn (sep [text "getImportedRules:",
616 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
619 selectGated gates decl_bag
620 -- Select only those decls whose gates are *all* in 'gates'
622 | opt_NoPruneDecls -- Just to try the effect of not gating at all
623 = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
627 = foldrBag select ([], emptyBag) decl_bag
629 select (reqd, decl) (yes, no)
630 | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
631 | otherwise = (yes, (reqd,decl) `consBag` no)
633 lookupFixity :: Name -> RnMS Fixity
635 | isLocallyDefined name
636 = getFixityEnv `thenRn` \ local_fix_env ->
637 case lookupNameEnv local_fix_env name of
638 Just (FixitySig _ fix _) -> returnRn fix
639 Nothing -> returnRn defaultFixity
641 | otherwise -- Imported
642 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
643 -- and consulting the Ifaces that comes back from that, because the interface
644 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
645 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
646 -- right away (after all, it's possible that nothing from B will be used).
647 -- When we come across a use of 'f', we need to know its fixity, and it's then,
648 -- and only then, that we load B.hi. That is what's happening here.
649 = loadHomeInterface doc name `thenRn` \ ifaces ->
650 case lookupNameEnv (iFixes ifaces) name of
651 Just (FixitySig _ fix _) -> returnRn fix
652 Nothing -> returnRn defaultFixity
654 doc = ptext SLIT("Checking fixity for") <+> ppr name
658 %*********************************************************
660 \subsection{Keeping track of what we've slurped, and version numbers}
662 %*********************************************************
664 getImportVersions figures out what the ``usage information'' for this
665 moudule is; that is, what it must record in its interface file as the
666 things it uses. It records:
669 \item anything reachable from its body code
670 \item any module exported with a @module Foo@.
673 Why the latter? Because if @Foo@ changes then this module's export list
674 will change, so we must recompile this module at least as far as
675 making a new interface file --- but in practice that means complete
680 module A( f, g ) where | module B( f ) where
681 import B( f ) | f = h 3
685 Should we record @B.f@ in @A@'s usages? In fact we don't. Certainly,
686 if anything about @B.f@ changes than anyone who imports @A@ should be
687 recompiled; they'll get an early exit if they don't use @B.f@.
688 However, even if @B.f@ doesn't change at all, @B.h@ may do so, and
689 this change may not be reflected in @f@'s version number. So there
690 are two things going on when compiling module @A@:
693 \item Are @A.o@ and @A.hi@ correct? Then we can bale out early.
694 \item Should modules that import @A@ be recompiled?
697 For (1) it is slightly harmful to record @B.f@ in @A@'s usages,
698 because a change in @B.f@'s version will provoke full recompilation of
699 @A@, producing an identical @A.o@, and @A.hi@ differing only in its
700 usage-version of @B.f@ (and this usage-version info isn't used by any
703 For (2), because of the tricky @B.h@ question above, we ensure that
704 @A.hi@ is touched (even if identical to its previous version) if A's
705 recompilation was triggered by an imported @.hi@ file date change.
706 Given that, there's no need to record @B.f@ in @A@'s usages.
708 On the other hand, if @A@ exports @module B@, then we {\em do} count
709 @module B@ among @A@'s usages, because we must recompile @A@ to ensure
710 that @A.hi@ changes appropriately.
712 HOWEVER, we *do* record the usage
714 in A.hi, to record the fact that A does import B. This is used to decide
715 to look to look for B.hi rather than B.hi-boot when compiling a module that
716 imports A. This line says that A imports B, but uses nothing in it.
717 So we'll get an early bale-out when compiling A if B's version changes.
720 getImportVersions :: ModuleName -- Name of this module
721 -> ExportEnv -- Info about exports
722 -> RnMG (VersionInfo Name) -- Version info for these names
724 getImportVersions this_mod (ExportEnv export_avails _ export_all_mods)
725 = getIfacesRn `thenRn` \ ifaces ->
727 mod_map = iImpModInfo ifaces
728 imp_names = iVSlurp ifaces
730 -- mv_map groups together all the things imported from a particular module.
731 mv_map :: FiniteMap ModuleName [(Name,Version)]
732 mv_map = foldr add_mv emptyFM imp_names
734 -- Build the result list by adding info for each module.
735 -- For (a) a library module, we don't record it at all unless it contains orphans
736 -- (We must never lose track of orphans.)
738 -- (b) a source-imported module, don't record the dependency at all
740 -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
741 -- *all* the module's dependencies other than the loop-breakers. We use
742 -- this info in findAndReadInterface to decide whether to look for a .hi file or
745 -- This means we won't track version changes, or orphans, from .hi-boot files.
746 -- The former is potentially rather bad news. It could be fixed by recording
747 -- whether something is a boot file along with the usage info for it, but
748 -- I can't be bothered just now.
750 mk_version_info mod_name (version, has_orphans, contents) so_far
752 go_for_it exports = (mod_name, version, has_orphans, exports) : so_far
755 Nothing -> -- We didn't even open the interface
756 -- This happens when a module, Foo, that we explicitly imported has
757 -- 'import Baz' in its interface file, recording that Baz is below
758 -- Foo in the module dependency hierarchy. We want to propagate this
759 -- information. The Nothing says that we didn't even open the interface
760 -- file but we must still propagate the dependeny info.
761 go_for_it (Specifically [])
763 Just (mod, boot_import, _) -- We did open the interface
764 | boot_import -- Don't record any usage info for this module
765 || (is_lib_module && not has_orphans)
768 | is_lib_module -- Record the module but not detailed
769 || mod_name `elem` export_all_mods -- version information for the imports
770 -> go_for_it Everything
773 -> case lookupFM mv_map mod_name of
774 Just whats_imported -> go_for_it (Specifically whats_imported)
775 Nothing -> go_for_it (Specifically [])
776 -- This happens if you have
778 -- but don't actually *use* anything from Foo
779 -- In which case record an empty dependency list
781 is_lib_module = isLibModule mod
784 -- A module shouldn't load its own interface
785 -- This seems like a convenient place to check
786 WARN( maybeToBool (lookupFM mod_map this_mod),
787 ptext SLIT("Wierd:") <+> ppr this_mod <+> ptext SLIT("loads its own interface") )
789 returnRn (foldFM mk_version_info [] mod_map)
791 add_mv v@(name, version) mv_map
792 = addToFM_C add_item mv_map mod [v]
794 mod = moduleName (nameModule name)
795 add_item vs _ = (v:vs)
800 = getIfacesRn `thenRn` \ ifaces ->
801 returnRn (iSlurp ifaces)
803 recordSlurp maybe_version avail
804 = getIfacesRn `thenRn` \ ifaces@(Ifaces { iSlurp = slurped_names,
805 iVSlurp = imp_names }) ->
807 new_slurped_names = addAvailToNameSet slurped_names avail
809 new_imp_names = case maybe_version of
810 Just version -> (availName avail, version) : imp_names
813 setIfacesRn (ifaces { iSlurp = new_slurped_names,
814 iVSlurp = new_imp_names })
818 %*********************************************************
820 \subsection{Getting binders out of a declaration}
822 %*********************************************************
824 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
825 It's used for both source code (from @availsFromDecl@) and interface files
828 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
829 are handled by the sourc-code specific stuff in @RnNames@.
832 getDeclBinders :: (RdrName -> SrcLoc -> RnM d Name) -- New-name function
834 -> RnM d (Maybe AvailInfo)
836 getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ src_loc))
837 = new_name tycon src_loc `thenRn` \ tycon_name ->
838 getConFieldNames new_name condecls `thenRn` \ sub_names ->
839 returnRn (Just (AvailTC tycon_name (tycon_name : nub sub_names)))
840 -- The "nub" is because getConFieldNames can legitimately return duplicates,
841 -- when a record declaration has the same field in multiple constructors
843 getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc))
844 = new_name tycon src_loc `thenRn` \ tycon_name ->
845 returnRn (Just (AvailTC tycon_name [tycon_name]))
847 getDeclBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ _ _ _ src_loc))
848 = new_name cname src_loc `thenRn` \ class_name ->
850 -- Record the names for the class ops
852 -- just want class-op sigs
853 op_sigs = filter isClassOpSig sigs
855 mapRn (getClassOpNames new_name) op_sigs `thenRn` \ sub_names ->
857 returnRn (Just (AvailTC class_name (class_name : sub_names)))
859 getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc))
860 = new_name var src_loc `thenRn` \ var_name ->
861 returnRn (Just (Avail var_name))
863 getDeclBinders new_name (FixD _) = returnRn Nothing
865 -- foreign declarations
866 getDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
867 | binds_haskell_name kind dyn
868 = new_name nm loc `thenRn` \ name ->
869 returnRn (Just (Avail name))
871 | otherwise -- a foreign export
872 = lookupImplicitOccRn nm `thenRn_`
875 getDeclBinders new_name (DefD _) = returnRn Nothing
876 getDeclBinders new_name (InstD _) = returnRn Nothing
877 getDeclBinders new_name (RuleD _) = returnRn Nothing
879 binds_haskell_name (FoImport _) _ = True
880 binds_haskell_name FoLabel _ = True
881 binds_haskell_name FoExport ext_nm = isDynamic ext_nm
884 getConFieldNames new_name (ConDecl con _ _ (RecCon fielddecls) src_loc : rest)
885 = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs ->
886 getConFieldNames new_name rest `thenRn` \ ns ->
889 fields = concat (map fst fielddecls)
891 getConFieldNames new_name (ConDecl con _ _ condecl src_loc : rest)
892 = new_name con src_loc `thenRn` \ n ->
895 new_name f src_loc `thenRn` \ new_f ->
897 _ -> returnRn [n]) `thenRn` \ nn ->
898 getConFieldNames new_name rest `thenRn` \ ns ->
901 getConFieldNames new_name [] = returnRn []
903 getClassOpNames new_name (ClassOpSig op _ _ _ src_loc) = new_name op src_loc
906 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
907 A the moment that's just the tycon and datacon that come with a class decl.
908 They aren't returned by @getDeclBinders@ because they aren't in scope;
909 but they {\em should} be put into the @DeclsMap@ of this module.
911 Note that this excludes the default-method names of a class decl,
912 and the dict fun of an instance decl, because both of these have
913 bindings of their own elsewhere.
916 getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ tname dname snames src_loc))
917 = new_name dname src_loc `thenRn` \ datacon_name ->
918 new_name tname src_loc `thenRn` \ tycon_name ->
919 sequenceRn [new_name n src_loc | n <- snames] `thenRn` \ scsel_names ->
920 returnRn (tycon_name : datacon_name : scsel_names)
922 getDeclSysBinders new_name other_decl
926 %*********************************************************
928 \subsection{Reading an interface file}
930 %*********************************************************
933 findAndReadIface :: SDoc -> ModuleName -> WhereFrom
934 -> Bool -- Only relevant for SystemImport
935 -- True <=> Look for a .hi file
936 -- False <=> Look for .hi-boot file unless there's
937 -- a library .hi file
938 -> RnM d (Bool, Maybe (Module, ParsedIface))
939 -- Bool is True if the interface actually read was a .hi-boot one
940 -- Nothing <=> file not found, or unreadable, or illegible
941 -- Just x <=> successfully found and parsed
943 findAndReadIface doc_str mod_name from hi_file
944 = traceRn trace_msg `thenRn_`
945 -- we keep two maps for interface files,
946 -- one for 'normal' ones, the other for .hi-boot files,
947 -- hence the need to signal which kind we're interested.
949 getHiMaps `thenRn` \ hi_maps ->
951 case find_path from hi_maps of
953 (hi_boot, Just (fpath, mod)) -> traceRn (ptext SLIT("...reading from") <+> text fpath)
955 readIface mod fpath `thenRn` \ result ->
956 returnRn (hi_boot, result)
957 (hi_boot, Nothing) -> traceRn (ptext SLIT("...not found")) `thenRn_`
958 returnRn (hi_boot, Nothing)
960 find_path ImportByUser (hi_map, _) = (False, lookupFM hi_map mod_name)
961 find_path ImportByUserSource (_, hiboot_map) = (True, lookupFM hiboot_map mod_name)
963 find_path ImportBySystem (hi_map, hiboot_map)
965 = -- If the module we seek is in our dependent set,
966 -- Look for a .hi file
967 (False, lookupFM hi_map mod_name)
970 -- Check if there's a library module of that name
971 -- If not, look for an hi-boot file
972 = case lookupFM hi_map mod_name of
973 stuff@(Just (_, mod)) | isLibModule mod -> (False, stuff)
974 other -> (True, lookupFM hiboot_map mod_name)
976 trace_msg = sep [hsep [ptext SLIT("Reading"),
978 ptext SLIT("interface for"),
979 pprModuleName mod_name <> semi],
980 nest 4 (ptext SLIT("reason:") <+> doc_str)]
983 @readIface@ tries just the one file.
986 readIface :: Module -> String -> RnM d (Maybe (Module, ParsedIface))
987 -- Nothing <=> file not found, or unreadable, or illegible
988 -- Just x <=> successfully found and parsed
989 readIface the_mod file_path
990 = ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
993 case parseIface contents
994 PState{ bol = 0#, atbol = 1#,
997 loc = mkSrcLoc (mkFastString file_path) 1 } of
998 POk _ (PIface mod_nm iface) ->
999 warnCheckRn (mod_nm == moduleName the_mod)
1000 (hiModuleNameMismatchWarn the_mod mod_nm) `thenRn_`
1001 returnRn (Just (the_mod, iface))
1003 PFailed err -> failWithRn Nothing err
1004 other -> failWithRn Nothing (ptext SLIT("Unrecognisable interface file"))
1005 -- This last case can happen if the interface file is (say) empty
1006 -- in which case the parser thinks it looks like an IdInfo or
1007 -- something like that. Just an artefact of the fact that the
1008 -- parser is used for several purposes at once.
1011 | isDoesNotExistError err -> returnRn Nothing
1012 | otherwise -> failWithRn Nothing (cannaeReadFile file_path err)
1015 %*********************************************************
1019 %*********************************************************
1022 noIfaceErr filename boot_file
1023 = hsep [ptext SLIT("Could not find valid"), boot,
1024 ptext SLIT("interface file"), quotes (pprModule filename)]
1026 boot | boot_file = ptext SLIT("[boot]")
1029 cannaeReadFile file err
1030 = hcat [ptext SLIT("Failed in reading file: "),
1032 ptext SLIT("; error="),
1036 = ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name)
1038 getDeclWarn name loc
1039 = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),
1040 ptext SLIT("desired at") <+> ppr loc]
1044 "Compiler tried to import decl from interface file with same name as module."),
1046 "(possible cause: module name clashes with interface file already in scope.)")
1048 hsep [ptext SLIT("name:"), quotes (ppr name)]
1050 warnRedundantSourceImport mod_name
1051 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
1052 <+> quotes (pprModuleName mod_name)
1054 hiModuleNameMismatchWarn :: Module -> ModuleName -> Message
1055 hiModuleNameMismatchWarn requested_mod mod_nm =
1056 hsep [ ptext SLIT("Something is amiss; requested module name")
1057 , pprModule requested_mod
1058 , ptext SLIT("differs from name found in the interface file ")
1059 , pprModuleName mod_nm