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 loadDeprec :: Module -> DeprecationEnv -> RdrNameDeprecation -> RnM d DeprecationEnv
345 loadDeprec mod deprec_env (DeprecMod txt)
346 = traceRn (text "module deprecation not yet implemented:" <+> ppr mod <> colon <+> ppr txt) `thenRn_`
348 loadDeprec mod deprec_env (DeprecName rdr_name txt)
349 = setModuleRn (moduleName mod) $
350 mkImportedGlobalFromRdrName rdr_name `thenRn` \ name ->
351 traceRn (text "loaded deprecation for" <+> ppr name <> colon <+> ppr txt) `thenRn_`
352 returnRn (addToNameEnv deprec_env name (DeprecName name txt))
356 %********************************************************
358 \subsection{Loading usage information}
360 %********************************************************
363 checkUpToDate :: ModuleName -> RnMG Bool -- True <=> no need to recompile
364 checkUpToDate mod_name
365 = getIfacesRn `thenRn` \ ifaces ->
366 findAndReadIface doc_str mod_name
368 (error "checkUpToDate") `thenRn` \ (_, read_result) ->
370 -- CHECK WHETHER WE HAVE IT ALREADY
372 Nothing -> -- Old interface file not found, so we'd better bail out
373 traceRn (sep [ptext SLIT("Didnt find old iface"),
374 pprModuleName mod_name]) `thenRn_`
378 -> -- Found it, so now check it
379 checkModUsage (pi_usages iface)
381 -- Only look in current directory, with suffix .hi
382 doc_str = sep [ptext SLIT("need usage info from"), pprModuleName mod_name]
384 checkModUsage [] = returnRn True -- Yes! Everything is up to date!
386 checkModUsage ((mod_name, old_mod_vers, _, Specifically []) : rest)
387 -- If CurrentModule.hi contains
389 -- then that simply records that Foo lies below CurrentModule in the
390 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
391 -- In this case we don't even want to open Foo's interface.
392 = traceRn (ptext SLIT("Nothing used from:") <+> ppr mod_name) `thenRn_`
393 checkModUsage rest -- This one's ok, so check the rest
395 checkModUsage ((mod_name, old_mod_vers, _, whats_imported) : rest)
396 = loadInterface doc_str mod_name ImportBySystem `thenRn` \ (mod, ifaces) ->
398 maybe_mod_vers = case lookupFM (iImpModInfo ifaces) mod_name of
399 Just (version, _, Just (_, _, _)) -> Just version
402 case maybe_mod_vers of {
403 Nothing -> -- If we can't find a version number for the old module then
404 -- bail out saying things aren't up to date
405 traceRn (sep [ptext SLIT("Can't find version number for module"),
406 pprModuleName mod_name])
407 `thenRn_` returnRn False ;
411 -- If the module version hasn't changed, just move on
412 if new_mod_vers == old_mod_vers then
413 traceRn (sep [ptext SLIT("Module version unchanged:"), pprModuleName mod_name])
414 `thenRn_` checkModUsage rest
416 traceRn (sep [ptext SLIT("Module version has changed:"), pprModuleName mod_name])
418 -- Module version changed, so check entities inside
420 -- If the usage info wants to say "I imported everything from this module"
421 -- it does so by making whats_imported equal to Everything
422 -- In that case, we must recompile
423 case whats_imported of {
424 Everything -> traceRn (ptext SLIT("...and I needed the whole module")) `thenRn_`
425 returnRn False; -- Bale out
427 Specifically old_local_vers ->
429 -- Non-empty usage list, so check item by item
430 checkEntityUsage mod_name (iDecls ifaces) old_local_vers `thenRn` \ up_to_date ->
432 traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_`
433 checkModUsage rest -- This one's ok, so check the rest
435 returnRn False -- This one failed, so just bail out now
438 doc_str = sep [ptext SLIT("need version info for"), pprModuleName mod_name]
441 checkEntityUsage mod decls []
442 = returnRn True -- Yes! All up to date!
444 checkEntityUsage mod decls ((occ_name,old_vers) : rest)
445 = mkImportedGlobalName mod occ_name `thenRn` \ name ->
446 case lookupNameEnv decls name of
448 Nothing -> -- We used it before, but it ain't there now
449 traceRn (sep [ptext SLIT("No longer exported:"), ppr name])
450 `thenRn_` returnRn False
452 Just (new_vers,_,_,_) -- It's there, but is it up to date?
453 | new_vers == old_vers
454 -- Up to date, so check the rest
455 -> checkEntityUsage mod decls rest
458 -- Out of date, so bale out
459 -> traceRn (sep [ptext SLIT("Out of date:"), ppr name]) `thenRn_`
464 %*********************************************************
466 \subsection{Getting in a declaration}
468 %*********************************************************
471 importDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
472 -- Returns Nothing for
475 -- (c) already slurped
481 = getSlurped `thenRn` \ already_slurped ->
482 if name `elemNameSet` already_slurped then
483 returnRn Nothing -- Already dealt with
485 if isLocallyDefined name then -- Don't bring in decls from
486 -- the renamed module's own interface file
487 addWarnRn (importDeclWarn name) `thenRn_`
490 getNonWiredInDecl name
494 getNonWiredInDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
495 getNonWiredInDecl needed_name
496 = traceRn doc_str `thenRn_`
497 loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
498 case lookupNameEnv (iDecls ifaces) needed_name of
500 Just (version,avail,_,decl)
501 -> recordSlurp (Just version) avail `thenRn_`
504 Nothing -- Can happen legitimately for "Optional" occurrences
505 -> addErrRn (getDeclErr needed_name) `thenRn_`
508 doc_str = ptext SLIT("need decl for") <+> ppr needed_name
511 @getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
512 It behaves exactly as if the wired in decl were actually in an interface file.
515 \item if the wired-in name is a data type constructor or a data constructor,
516 it brings in the type constructor and all the data constructors; and
517 marks as ``occurrences'' any free vars of the data con.
519 \item similarly for synonum type constructor
521 \item if the wired-in name is another wired-in Id, it marks as ``occurrences''
522 the free vars of the Id's type.
524 \item it loads the interface file for the wired-in thing for the
525 sole purpose of making sure that its instance declarations are available
527 All this is necessary so that we know all types that are ``in play'', so
528 that we know just what instances to bring into scope.
533 %*********************************************************
535 \subsection{Getting what a module exports}
537 %*********************************************************
539 @getInterfaceExports@ is called only for directly-imported modules.
542 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
543 getInterfaceExports mod_name from
544 = loadInterface doc_str mod_name from `thenRn` \ (mod, ifaces) ->
545 case lookupFM (iImpModInfo ifaces) mod_name of
546 Nothing -> -- Not there; it must be that the interface file wasn't found;
547 -- the error will have been reported already.
548 -- (Actually loadInterface should put the empty export env in there
549 -- anyway, but this does no harm.)
552 Just (_, _, Just (mod, _, avails)) -> returnRn (mod, avails)
554 doc_str = sep [pprModuleName mod_name, ptext SLIT("is directly imported")]
558 %*********************************************************
560 \subsection{Instance declarations are handled specially}
562 %*********************************************************
565 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
566 getImportedInstDecls gates
567 = -- First, load any orphan-instance modules that aren't aready loaded
568 -- Orphan-instance modules are recorded in the module dependecnies
569 getIfacesRn `thenRn` \ ifaces ->
572 [mod | (mod, (_, True, Nothing)) <- fmToList (iImpModInfo ifaces)]
574 loadOrphanModules orphan_mods `thenRn_`
576 -- Now we're ready to grab the instance declarations
577 -- Find the un-gated ones and return them,
578 -- removing them from the bag kept in Ifaces
579 getIfacesRn `thenRn` \ ifaces ->
581 (decls, new_insts) = selectGated gates (iInsts ifaces)
583 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
585 traceRn (sep [text "getImportedInstDecls:",
586 nest 4 (fsep (map ppr gate_list)),
587 text "Slurped" <+> int (length decls) <+> text "instance declarations",
588 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
591 gate_list = nameSetToList gates
593 load_home gate | isLocallyDefined gate
596 = loadHomeInterface (ppr gate <+> text "is an instance gate") gate `thenRn_`
599 ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
601 HsForAllTy _ _ tau -> ppr tau
604 getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
606 | opt_IgnoreIfacePragmas = returnRn []
608 = getIfacesRn `thenRn` \ ifaces ->
610 gates = iSlurp ifaces -- Anything at all that's been slurped
611 (decls, new_rules) = selectGated gates (iRules ifaces)
613 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
614 traceRn (sep [text "getImportedRules:",
615 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
618 selectGated gates decl_bag
619 -- Select only those decls whose gates are *all* in 'gates'
621 | opt_NoPruneDecls -- Just to try the effect of not gating at all
622 = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
626 = foldrBag select ([], emptyBag) decl_bag
628 select (reqd, decl) (yes, no)
629 | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
630 | otherwise = (yes, (reqd,decl) `consBag` no)
632 lookupFixity :: Name -> RnMS Fixity
634 | isLocallyDefined name
635 = getFixityEnv `thenRn` \ local_fix_env ->
636 case lookupNameEnv local_fix_env name of
637 Just (FixitySig _ fix _) -> returnRn fix
638 Nothing -> returnRn defaultFixity
640 | otherwise -- Imported
641 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
642 -- and consulting the Ifaces that comes back from that, because the interface
643 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
644 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
645 -- right away (after all, it's possible that nothing from B will be used).
646 -- When we come across a use of 'f', we need to know its fixity, and it's then,
647 -- and only then, that we load B.hi. That is what's happening here.
648 = loadHomeInterface doc name `thenRn` \ ifaces ->
649 case lookupNameEnv (iFixes ifaces) name of
650 Just (FixitySig _ fix _) -> returnRn fix
651 Nothing -> returnRn defaultFixity
653 doc = ptext SLIT("Checking fixity for") <+> ppr name
657 %*********************************************************
659 \subsection{Keeping track of what we've slurped, and version numbers}
661 %*********************************************************
663 getImportVersions figures out what the ``usage information'' for this
664 moudule is; that is, what it must record in its interface file as the
665 things it uses. It records:
668 \item anything reachable from its body code
669 \item any module exported with a @module Foo@.
672 Why the latter? Because if @Foo@ changes then this module's export list
673 will change, so we must recompile this module at least as far as
674 making a new interface file --- but in practice that means complete
679 module A( f, g ) where | module B( f ) where
680 import B( f ) | f = h 3
684 Should we record @B.f@ in @A@'s usages? In fact we don't. Certainly,
685 if anything about @B.f@ changes than anyone who imports @A@ should be
686 recompiled; they'll get an early exit if they don't use @B.f@.
687 However, even if @B.f@ doesn't change at all, @B.h@ may do so, and
688 this change may not be reflected in @f@'s version number. So there
689 are two things going on when compiling module @A@:
692 \item Are @A.o@ and @A.hi@ correct? Then we can bale out early.
693 \item Should modules that import @A@ be recompiled?
696 For (1) it is slightly harmful to record @B.f@ in @A@'s usages,
697 because a change in @B.f@'s version will provoke full recompilation of
698 @A@, producing an identical @A.o@, and @A.hi@ differing only in its
699 usage-version of @B.f@ (and this usage-version info isn't used by any
702 For (2), because of the tricky @B.h@ question above, we ensure that
703 @A.hi@ is touched (even if identical to its previous version) if A's
704 recompilation was triggered by an imported @.hi@ file date change.
705 Given that, there's no need to record @B.f@ in @A@'s usages.
707 On the other hand, if @A@ exports @module B@, then we {\em do} count
708 @module B@ among @A@'s usages, because we must recompile @A@ to ensure
709 that @A.hi@ changes appropriately.
711 HOWEVER, we *do* record the usage
713 in A.hi, to record the fact that A does import B. This is used to decide
714 to look to look for B.hi rather than B.hi-boot when compiling a module that
715 imports A. This line says that A imports B, but uses nothing in it.
716 So we'll get an early bale-out when compiling A if B's version changes.
719 getImportVersions :: ModuleName -- Name of this module
720 -> ExportEnv -- Info about exports
721 -> RnMG (VersionInfo Name) -- Version info for these names
723 getImportVersions this_mod (ExportEnv export_avails _ export_all_mods)
724 = getIfacesRn `thenRn` \ ifaces ->
726 mod_map = iImpModInfo ifaces
727 imp_names = iVSlurp ifaces
729 -- mv_map groups together all the things imported from a particular module.
730 mv_map :: FiniteMap ModuleName [(Name,Version)]
731 mv_map = foldr add_mv emptyFM imp_names
733 -- Build the result list by adding info for each module.
734 -- For (a) a library module, we don't record it at all unless it contains orphans
735 -- (We must never lose track of orphans.)
737 -- (b) a source-imported module, don't record the dependency at all
739 -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
740 -- *all* the module's dependencies other than the loop-breakers. We use
741 -- this info in findAndReadInterface to decide whether to look for a .hi file or
744 -- This means we won't track version changes, or orphans, from .hi-boot files.
745 -- The former is potentially rather bad news. It could be fixed by recording
746 -- whether something is a boot file along with the usage info for it, but
747 -- I can't be bothered just now.
749 mk_version_info mod_name (version, has_orphans, contents) so_far
751 go_for_it exports = (mod_name, version, has_orphans, exports) : so_far
754 Nothing -> -- We didn't even open the interface
755 -- This happens when a module, Foo, that we explicitly imported has
756 -- 'import Baz' in its interface file, recording that Baz is below
757 -- Foo in the module dependency hierarchy. We want to propagate this
758 -- information. The Nothing says that we didn't even open the interface
759 -- file but we must still propagate the dependeny info.
760 go_for_it (Specifically [])
762 Just (mod, boot_import, _) -- We did open the interface
763 | boot_import -- Don't record any usage info for this module
764 || (is_lib_module && not has_orphans)
767 | is_lib_module -- Record the module but not detailed
768 || mod_name `elem` export_all_mods -- version information for the imports
769 -> go_for_it Everything
772 -> case lookupFM mv_map mod_name of
773 Just whats_imported -> go_for_it (Specifically whats_imported)
774 Nothing -> go_for_it (Specifically [])
775 -- This happens if you have
777 -- but don't actually *use* anything from Foo
778 -- In which case record an empty dependency list
780 is_lib_module = isLibModule mod
783 -- A module shouldn't load its own interface
784 -- This seems like a convenient place to check
785 WARN( maybeToBool (lookupFM mod_map this_mod),
786 ptext SLIT("Wierd:") <+> ppr this_mod <+> ptext SLIT("loads its own interface") )
788 returnRn (foldFM mk_version_info [] mod_map)
790 add_mv v@(name, version) mv_map
791 = addToFM_C add_item mv_map mod [v]
793 mod = moduleName (nameModule name)
794 add_item vs _ = (v:vs)
799 = getIfacesRn `thenRn` \ ifaces ->
800 returnRn (iSlurp ifaces)
802 recordSlurp maybe_version avail
803 = getIfacesRn `thenRn` \ ifaces@(Ifaces { iSlurp = slurped_names,
804 iVSlurp = imp_names }) ->
806 new_slurped_names = addAvailToNameSet slurped_names avail
808 new_imp_names = case maybe_version of
809 Just version -> (availName avail, version) : imp_names
812 setIfacesRn (ifaces { iSlurp = new_slurped_names,
813 iVSlurp = new_imp_names })
817 %*********************************************************
819 \subsection{Getting binders out of a declaration}
821 %*********************************************************
823 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
824 It's used for both source code (from @availsFromDecl@) and interface files
827 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
828 are handled by the sourc-code specific stuff in @RnNames@.
831 getDeclBinders :: (RdrName -> SrcLoc -> RnM d Name) -- New-name function
833 -> RnM d (Maybe AvailInfo)
835 getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ src_loc))
836 = new_name tycon src_loc `thenRn` \ tycon_name ->
837 getConFieldNames new_name condecls `thenRn` \ sub_names ->
838 returnRn (Just (AvailTC tycon_name (tycon_name : nub sub_names)))
839 -- The "nub" is because getConFieldNames can legitimately return duplicates,
840 -- when a record declaration has the same field in multiple constructors
842 getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc))
843 = new_name tycon src_loc `thenRn` \ tycon_name ->
844 returnRn (Just (AvailTC tycon_name [tycon_name]))
846 getDeclBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ _ _ _ src_loc))
847 = new_name cname src_loc `thenRn` \ class_name ->
849 -- Record the names for the class ops
851 -- just want class-op sigs
852 op_sigs = filter isClassOpSig sigs
854 mapRn (getClassOpNames new_name) op_sigs `thenRn` \ sub_names ->
856 returnRn (Just (AvailTC class_name (class_name : sub_names)))
858 getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc))
859 = new_name var src_loc `thenRn` \ var_name ->
860 returnRn (Just (Avail var_name))
862 getDeclBinders new_name (FixD _) = returnRn Nothing
864 -- foreign declarations
865 getDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
866 | binds_haskell_name kind dyn
867 = new_name nm loc `thenRn` \ name ->
868 returnRn (Just (Avail name))
870 | otherwise -- a foreign export
871 = lookupImplicitOccRn nm `thenRn_`
874 getDeclBinders new_name (DefD _) = returnRn Nothing
875 getDeclBinders new_name (InstD _) = returnRn Nothing
876 getDeclBinders new_name (RuleD _) = returnRn Nothing
878 binds_haskell_name (FoImport _) _ = True
879 binds_haskell_name FoLabel _ = True
880 binds_haskell_name FoExport ext_nm = isDynamic ext_nm
883 getConFieldNames new_name (ConDecl con _ _ (RecCon fielddecls) src_loc : rest)
884 = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs ->
885 getConFieldNames new_name rest `thenRn` \ ns ->
888 fields = concat (map fst fielddecls)
890 getConFieldNames new_name (ConDecl con _ _ condecl src_loc : rest)
891 = new_name con src_loc `thenRn` \ n ->
894 new_name f src_loc `thenRn` \ new_f ->
896 _ -> returnRn [n]) `thenRn` \ nn ->
897 getConFieldNames new_name rest `thenRn` \ ns ->
900 getConFieldNames new_name [] = returnRn []
902 getClassOpNames new_name (ClassOpSig op _ _ _ src_loc) = new_name op src_loc
905 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
906 A the moment that's just the tycon and datacon that come with a class decl.
907 They aren't returned by @getDeclBinders@ because they aren't in scope;
908 but they {\em should} be put into the @DeclsMap@ of this module.
910 Note that this excludes the default-method names of a class decl,
911 and the dict fun of an instance decl, because both of these have
912 bindings of their own elsewhere.
915 getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ tname dname snames src_loc))
916 = new_name dname src_loc `thenRn` \ datacon_name ->
917 new_name tname src_loc `thenRn` \ tycon_name ->
918 sequenceRn [new_name n src_loc | n <- snames] `thenRn` \ scsel_names ->
919 returnRn (tycon_name : datacon_name : scsel_names)
921 getDeclSysBinders new_name other_decl
925 %*********************************************************
927 \subsection{Reading an interface file}
929 %*********************************************************
932 findAndReadIface :: SDoc -> ModuleName -> WhereFrom
933 -> Bool -- Only relevant for SystemImport
934 -- True <=> Look for a .hi file
935 -- False <=> Look for .hi-boot file unless there's
936 -- a library .hi file
937 -> RnM d (Bool, Maybe (Module, ParsedIface))
938 -- Bool is True if the interface actually read was a .hi-boot one
939 -- Nothing <=> file not found, or unreadable, or illegible
940 -- Just x <=> successfully found and parsed
942 findAndReadIface doc_str mod_name from hi_file
943 = traceRn trace_msg `thenRn_`
944 -- we keep two maps for interface files,
945 -- one for 'normal' ones, the other for .hi-boot files,
946 -- hence the need to signal which kind we're interested.
948 getHiMaps `thenRn` \ hi_maps ->
950 case find_path from hi_maps of
952 (hi_boot, Just (fpath, mod)) -> traceRn (ptext SLIT("...reading from") <+> text fpath)
954 readIface mod fpath `thenRn` \ result ->
955 returnRn (hi_boot, result)
956 (hi_boot, Nothing) -> traceRn (ptext SLIT("...not found")) `thenRn_`
957 returnRn (hi_boot, Nothing)
959 find_path ImportByUser (hi_map, _) = (False, lookupFM hi_map mod_name)
960 find_path ImportByUserSource (_, hiboot_map) = (True, lookupFM hiboot_map mod_name)
962 find_path ImportBySystem (hi_map, hiboot_map)
964 = -- If the module we seek is in our dependent set,
965 -- Look for a .hi file
966 (False, lookupFM hi_map mod_name)
969 -- Check if there's a library module of that name
970 -- If not, look for an hi-boot file
971 = case lookupFM hi_map mod_name of
972 stuff@(Just (_, mod)) | isLibModule mod -> (False, stuff)
973 other -> (True, lookupFM hiboot_map mod_name)
975 trace_msg = sep [hsep [ptext SLIT("Reading"),
977 ptext SLIT("interface for"),
978 pprModuleName mod_name <> semi],
979 nest 4 (ptext SLIT("reason:") <+> doc_str)]
982 @readIface@ tries just the one file.
985 readIface :: Module -> String -> RnM d (Maybe (Module, ParsedIface))
986 -- Nothing <=> file not found, or unreadable, or illegible
987 -- Just x <=> successfully found and parsed
988 readIface the_mod file_path
989 = ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
992 case parseIface contents
993 PState{ bol = 0#, atbol = 1#,
996 loc = mkSrcLoc (mkFastString file_path) 1 } of
997 POk _ (PIface mod_nm iface) ->
998 warnCheckRn (mod_nm == moduleName the_mod)
999 (hiModuleNameMismatchWarn the_mod mod_nm) `thenRn_`
1000 returnRn (Just (the_mod, iface))
1002 PFailed err -> failWithRn Nothing err
1003 other -> failWithRn Nothing (ptext SLIT("Unrecognisable interface file"))
1004 -- This last case can happen if the interface file is (say) empty
1005 -- in which case the parser thinks it looks like an IdInfo or
1006 -- something like that. Just an artefact of the fact that the
1007 -- parser is used for several purposes at once.
1010 | isDoesNotExistError err -> returnRn Nothing
1011 | otherwise -> failWithRn Nothing (cannaeReadFile file_path err)
1014 %*********************************************************
1018 %*********************************************************
1021 noIfaceErr filename boot_file
1022 = hsep [ptext SLIT("Could not find valid"), boot,
1023 ptext SLIT("interface file"), quotes (pprModule filename)]
1025 boot | boot_file = ptext SLIT("[boot]")
1028 cannaeReadFile file err
1029 = hcat [ptext SLIT("Failed in reading file: "),
1031 ptext SLIT("; error="),
1035 = ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name)
1037 getDeclWarn name loc
1038 = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),
1039 ptext SLIT("desired at") <+> ppr loc]
1043 "Compiler tried to import decl from interface file with same name as module."),
1045 "(possible cause: module name clashes with interface file already in scope.)")
1047 hsep [ptext SLIT("name:"), quotes (ppr name)]
1049 warnRedundantSourceImport mod_name
1050 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
1051 <+> quotes (pprModuleName mod_name)
1053 hiModuleNameMismatchWarn :: Module -> ModuleName -> Message
1054 hiModuleNameMismatchWarn requested_mod mod_nm =
1055 hsep [ ptext SLIT("Something is amiss; requested module name")
1056 , pprModule requested_mod
1057 , ptext SLIT("differs from name found in the interface file ")
1058 , pprModuleName mod_nm