2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnIfaces]{Cacheing and Renaming of Interfaces}
13 slurpImpDecls, closeDecls,
15 RecompileRequired, outOfDate, upToDate, recompileRequired
19 #include "HsVersions.h"
21 import CmdLineOpts ( opt_IgnoreIfacePragmas, opt_NoPruneDecls )
23 import HsSyn ( HsDecl(..), Sig(..), TyClDecl(..), ConDecl(..), ConDetails(..),
24 InstDecl(..), HsType(..), hsTyVarNames, getBangType
26 import HsImpExp ( ImportDecl(..) )
27 import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl )
28 import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl,
29 extractHsTyNames, extractHsCtxtTyNames,
30 tyClDeclFVs, ruleDeclFVs, instDeclFVs
32 import RnHiFiles ( tryLoadInterface, loadHomeInterface, loadInterface,
35 import RnSource ( rnTyClDecl, rnInstDecl, rnIfaceRuleDecl )
39 import Type ( namesOfType )
40 import TyCon ( isSynTyCon, getSynTyConDefn )
41 import Name ( Name {-instance NamedThing-}, nameOccName,
42 nameModule, isLocalName, nameUnique,
45 import Name ( elemNameEnv, delFromNameEnv )
46 import Module ( Module, ModuleEnv,
47 moduleName, isHomeModule,
48 ModuleName, WhereFrom(..),
50 extendModuleEnv_C, foldModuleEnv, lookupModuleEnv,
51 elemModuleSet, extendModuleSet
54 import PrelInfo ( wiredInThingEnv, fractionalClassKeys )
55 import TysWiredIn ( doubleTyCon )
56 import Maybes ( orElse )
60 import Util ( sortLt )
64 %*********************************************************
66 \subsection{Getting what a module exports}
68 %*********************************************************
70 @getInterfaceExports@ is called only for directly-imported modules.
73 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, [(ModuleName,Avails)])
74 getInterfaceExports mod_name from
75 = loadInterface doc_str mod_name from `thenRn` \ iface ->
76 returnRn (mi_module iface, mi_exports iface)
78 doc_str = sep [ppr mod_name, ptext SLIT("is directly imported")]
82 %*********************************************************
84 \subsection{Keeping track of what we've slurped, and version numbers}
86 %*********************************************************
88 mkImportInof figures out what the ``usage information'' for this
89 moudule is; that is, what it must record in its interface file as the
92 We produce a line for every module B below the module, A, currently being
95 to record the fact that A does import B indireclty. This is used to decide
96 to look to look for B.hi rather than B.hi-boot when compiling a module that
97 imports A. This line says that A imports B, but uses nothing in it.
98 So we'll get an early bale-out when compiling A if B's version changes.
101 mkImportInfo :: ModuleName -- Name of this module
102 -> [ImportDecl n] -- The import decls
103 -> RnMG [ImportVersion Name]
105 mkImportInfo this_mod imports
106 = getIfacesRn `thenRn` \ ifaces ->
107 getHomeIfaceTableRn `thenRn` \ hit ->
109 (imp_pkg_mods, imp_home_names) = iVSlurp ifaces
112 import_all_mods :: [ModuleName]
113 -- Modules where we imported all the names
114 -- (apart from hiding some, perhaps)
115 import_all_mods = [ m | ImportDecl m _ _ _ imp_list _ <- imports,
116 import_all imp_list ]
118 import_all (Just (False, _)) = False -- Imports are specified explicitly
119 import_all other = True -- Everything is imported
121 -- mv_map groups together all the things imported and used
122 -- from a particular module in this package
123 -- We use a finite map because we want the domain
124 mv_map :: ModuleEnv [Name]
125 mv_map = foldNameSet add_mv emptyModuleEnv imp_home_names
126 add_mv name mv_map = extendModuleEnv_C add_item mv_map mod [name]
128 mod = nameModule name
129 add_item names _ = name:names
131 -- In our usage list we record
132 -- a) Specifically: Detailed version info for imports from modules in this package
133 -- Gotten from iVSlurp plus import_all_mods
135 -- b) Everything: Just the module version for imports from modules in other packages
136 -- Gotten from iVSlurp plus import_all_mods
138 -- c) NothingAtAll: The name only of modules, Baz, in this package that are 'below' us,
139 -- but which we didn't need at all (this is needed only to decide whether
140 -- to open Baz.hi or Baz.hi-boot higher up the tree).
141 -- This happens when a module, Foo, that we explicitly imported has
142 -- 'import Baz' in its interface file, recording that Baz is below
143 -- Foo in the module dependency hierarchy. We want to propagate this info.
144 -- These modules are in a combination of HIT/PIT and iImpModInfo
146 -- d) NothingAtAll: The name only of all orphan modules we know of (this is needed
147 -- so that anyone who imports us can find the orphan modules)
148 -- These modules are in a combination of HIT/PIT and iImpModInfo
150 import_info0 = foldModuleEnv mk_imp_info [] pit
151 import_info1 = foldModuleEnv mk_imp_info import_info0 hit
152 import_info = [ (mod_name, orphans, is_boot, NothingAtAll)
153 | (mod_name, (orphans, is_boot)) <- fmToList (iImpModInfo ifaces) ] ++
156 mk_imp_info :: ModIface -> [ImportVersion Name] -> [ImportVersion Name]
157 mk_imp_info iface so_far
159 | Just ns <- lookupModuleEnv mv_map mod -- Case (a)
160 = go_for_it (Specifically mod_vers maybe_export_vers
161 (mk_import_items ns) rules_vers)
163 | mod `elemModuleSet` imp_pkg_mods -- Case (b)
164 = go_for_it (Everything mod_vers)
166 | import_all_mod -- Case (a) and (b); the import-all part
167 = if is_home_pkg_mod then
168 go_for_it (Specifically mod_vers (Just export_vers) [] rules_vers)
170 go_for_it (Everything mod_vers)
172 | is_home_pkg_mod || has_orphans -- Case (c) or (d)
173 = go_for_it NothingAtAll
177 go_for_it exports = (mod_name, has_orphans, mi_boot iface, exports) : so_far
179 mod = mi_module iface
180 mod_name = moduleName mod
181 is_home_pkg_mod = isHomeModule mod
182 version_info = mi_version iface
183 version_env = vers_decls version_info
184 mod_vers = vers_module version_info
185 rules_vers = vers_rules version_info
186 export_vers = vers_exports version_info
187 import_all_mod = mod_name `elem` import_all_mods
188 has_orphans = mi_orphan iface
190 -- The sort is to put them into canonical order
191 mk_import_items ns = [(n,v) | n <- sortLt lt_occ ns,
192 let v = lookupNameEnv version_env n `orElse`
193 pprPanic "mk_whats_imported" (ppr n)
196 lt_occ n1 n2 = nameOccName n1 < nameOccName n2
198 maybe_export_vers | import_all_mod = Just (vers_exports version_info)
199 | otherwise = Nothing
204 %*********************************************************
206 \subsection{Slurping declarations}
208 %*********************************************************
211 -------------------------------------------------------
212 slurpImpDecls source_fvs
213 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
215 -- The current slurped-set records all local things
216 slurpSourceRefs source_fvs `thenRn` \ (decls, needed) ->
218 -- Then get everything else
219 closeDecls decls needed
222 -------------------------------------------------------
223 slurpSourceRefs :: FreeVars -- Variables referenced in source
224 -> RnMG ([RenamedHsDecl],
225 FreeVars) -- Un-satisfied needs
226 -- The declaration (and hence home module) of each gate has
227 -- already been loaded
229 slurpSourceRefs source_fvs
230 = go_outer [] -- Accumulating decls
231 emptyFVs -- Unsatisfied needs
232 emptyFVs -- Accumulating gates
233 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
235 -- The outer loop repeatedly slurps the decls for the current gates
236 -- and the instance decls
238 -- The outer loop is needed because consider
240 go_outer decls fvs all_gates []
241 = returnRn (decls, fvs)
243 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
244 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
245 foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
246 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
247 rnIfaceInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
248 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
249 (nameSetToList (gates2 `minusNameSet` all_gates))
250 -- Knock out the all_gates because even if we don't slurp any new
251 -- decls we can get some apparently-new gates from wired-in names
253 go_inner (decls, fvs, gates) wanted_name
254 = importDecl wanted_name `thenRn` \ import_result ->
255 case import_result of
256 AlreadySlurped -> returnRn (decls, fvs, gates)
257 InTypeEnv ty_thing -> returnRn (decls, fvs, gates `plusFV` getWiredInGates ty_thing)
259 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
260 returnRn (TyClD new_decl : decls,
262 gates `plusFV` getGates source_fvs new_decl)
267 -------------------------------------------------------
268 -- closeDecls keeps going until the free-var set is empty
269 closeDecls decls needed
270 | not (isEmptyFVs needed)
271 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
272 closeDecls decls1 needed1
275 = getImportedRules `thenRn` \ rule_decls ->
277 [] -> returnRn decls -- No new rules, so we are done
278 other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' ->
280 rule_fvs = plusFVs (map ruleDeclFVs rule_decls')
282 traceRn (text "closeRules" <+> ppr rule_decls' $$ fsep (map ppr (nameSetToList rule_fvs))) `thenRn_`
283 closeDecls (map RuleD rule_decls' ++ decls) rule_fvs
287 -------------------------------------------------------
288 -- Augment decls with any decls needed by needed.
289 -- Return also free vars of the new decls (only)
290 slurpDecls decls needed
291 = go decls emptyFVs (nameSetToList needed)
293 go decls fvs [] = returnRn (decls, fvs)
294 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
297 -------------------------------------------------------
298 slurpDecl decls fvs wanted_name
299 = importDecl wanted_name `thenRn` \ import_result ->
300 case import_result of
301 -- Found a declaration... rename it
302 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
303 returnRn (TyClD new_decl:decls, fvs1 `plusFV` fvs)
305 -- No declaration... (wired in thing, or deferred, or already slurped)
306 other -> returnRn (decls, fvs)
309 -------------------------------------------------------
310 rnIfaceDecls rn decls = mapRn (rnIfaceDecl rn) decls
311 rnIfaceDecl rn (mod, decl) = initIfaceRnMS mod (rn decl)
313 rnIfaceInstDecls decls fvs gates inst_decls
314 = rnIfaceDecls rnInstDecl inst_decls `thenRn` \ inst_decls' ->
315 returnRn (map InstD inst_decls' ++ decls,
316 fvs `plusFV` plusFVs (map instDeclFVs inst_decls'),
317 gates `plusFV` plusFVs (map getInstDeclGates inst_decls'))
319 rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl) `thenRn` \ decl' ->
320 returnRn (decl', tyClDeclFVs decl')
326 = getIfacesRn `thenRn` \ ifaces ->
327 returnRn (iSlurp ifaces)
329 recordSlurp ifaces@(Ifaces { iDecls = (decls_map, n_slurped),
330 iSlurp = slurped_names,
331 iVSlurp = (imp_mods, imp_names) })
333 = ASSERT2( not (isLocalName (availName avail)), ppr avail )
334 ifaces { iDecls = (decls_map', n_slurped+1),
335 iSlurp = new_slurped_names,
336 iVSlurp = new_vslurp }
338 decls_map' = foldl delFromNameEnv decls_map (availNames avail)
339 main_name = availName avail
340 mod = nameModule main_name
341 new_slurped_names = addAvailToNameSet slurped_names avail
342 new_vslurp | isHomeModule mod = (imp_mods, addOneToNameSet imp_names main_name)
343 | otherwise = (extendModuleSet imp_mods mod, imp_names)
345 recordLocalSlurps new_names
346 = getIfacesRn `thenRn` \ ifaces ->
347 setIfacesRn (ifaces { iSlurp = iSlurp ifaces `unionNameSets` new_names })
352 %*********************************************************
354 \subsection{Extracting the `gates'}
356 %*********************************************************
360 We want to avoid sucking in too many instance declarations.
361 An instance decl is only useful if the types and classes mentioned in
362 its 'head' are all available in the program being compiled. E.g.
364 instance (..) => C (T1 a) (T2 b) where ...
366 is only useful if C, T1 and T2 are all "available". So we keep
367 instance decls that have been parsed from .hi files, but not yet
368 slurped in, in a pool called the 'gated instance pool'.
369 Each has its set of 'gates': {C, T1, T2} in the above example.
371 More precisely, the gates of a module are the types and classes
372 that are mentioned in:
375 b) the type of an Id that's mentioned in the source code
376 [includes constructors and selectors]
377 c) the RHS of a type synonym that is a gate
378 d) the superclasses of a class that is a gate
379 e) the context of an instance decl that is slurped in
381 We slurp in an instance decl from the gated instance pool iff
383 all its gates are either in the gates of the module,
384 or are a previously-loaded class.
386 The latter constraint is because there might have been an instance
387 decl slurped in during an earlier compilation, like this:
389 instance Foo a => Baz (Maybe a) where ...
391 In the module being compiled we might need (Baz (Maybe T)), where T
392 is defined in this module, and hence we need (Foo T). So @Foo@ becomes
393 a gate. But there's no way to 'see' that, so we simply treat all
394 previously-loaded classes as gates.
396 Consructors and class operations
397 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
398 When we import a declaration like
400 data T = T1 Wibble | T2 Wobble
402 we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless}
403 @T1@, @T2@ respectively are mentioned by the user program. If only
404 @T@ is mentioned we want only @T@ to be a gate; that way we don't suck
405 in useless instance decls for (say) @Eq Wibble@, when they can't
408 And that's just what (b) says: we only treat T1's type as a gate if
409 T1 is mentioned. getGates, which deals with decls we are slurping in,
410 has to be a bit careful, because a mention of T1 will slurp in T's whole
413 -----------------------------
414 @getGates@ takes a newly imported (and renamed) decl, and the free
415 vars of the source program, and extracts from the decl the gate names.
418 getGates :: FreeVars -- Things mentioned in the source program
422 getGates source_fvs decl
423 = get_gates (\n -> n `elemNameSet` source_fvs) decl
425 get_gates is_used (IfaceSig _ ty _ _)
426 = extractHsTyNames ty
428 get_gates is_used (ClassDecl ctxt cls tvs _ sigs _ _ _ )
429 = (delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
431 `addOneToNameSet` cls)
432 `plusFV` maybe_double
434 get (ClassOpSig n _ ty _)
435 | is_used n = extractHsTyNames ty
436 | otherwise = emptyFVs
438 -- If we load any numeric class that doesn't have
439 -- Int as an instance, add Double to the gates.
440 -- This takes account of the fact that Double might be needed for
441 -- defaulting, but we don't want to load Double (and all its baggage)
442 -- if the more exotic classes aren't used at all.
443 maybe_double | nameUnique cls `elem` fractionalClassKeys
444 = unitFV (getName doubleTyCon)
448 get_gates is_used (TySynonym tycon tvs ty _)
449 = delListFromNameSet (extractHsTyNames ty) (hsTyVarNames tvs)
450 -- A type synonym type constructor isn't a "gate" for instance decls
452 get_gates is_used (TyData _ ctxt tycon tvs cons _ _ _ _ _)
453 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
455 `addOneToNameSet` tycon
457 get (ConDecl n _ tvs ctxt details _)
459 -- If the constructor is method, get fvs from all its fields
460 = delListFromNameSet (get_details details `plusFV`
461 extractHsCtxtTyNames ctxt)
463 get (ConDecl n _ tvs ctxt (RecCon fields) _)
464 -- Even if the constructor isn't mentioned, the fields
465 -- might be, as selectors. They can't mention existentially
466 -- bound tyvars (typechecker checks for that) so no need for
467 -- the deleteListFromNameSet part
468 = foldr (plusFV . get_field) emptyFVs fields
470 get other_con = emptyFVs
472 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
473 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
474 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
476 get_field (fs,t) | any is_used fs = get_bang t
477 | otherwise = emptyFVs
479 get_bang bty = extractHsTyNames (getBangType bty)
482 @getWiredInGates@ is just like @getGates@, but it sees a previously-loaded
483 thing rather than a declaration.
486 getWiredInGates :: TyThing -> FreeVars
487 -- The TyThing is one that we already have in our type environment, either
488 -- a) because the TyCon or Id is wired in, or
489 -- b) from a previous compile
490 -- Either way, we might have instance decls in the (persistent) collection
491 -- of parsed-but-not-slurped instance decls that should be slurped in.
492 -- This might be the first module that mentions both the type and the class
493 -- for that instance decl, even though both the type and the class were
494 -- mentioned in other modules, and hence are in the type environment
496 getWiredInGates (AnId the_id) = namesOfType (idType the_id)
497 getWiredInGates (AClass cl) = emptyFVs -- The superclasses must also be previously
498 -- loaded, and hence are automatically gates
499 getWiredInGates (ATyCon tc)
500 | isSynTyCon tc = delListFromNameSet (namesOfType ty) (map getName tyvars)
501 | otherwise = unitFV (getName tc)
503 (tyvars,ty) = getSynTyConDefn tc
505 getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty
509 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameInstDecl)]
510 getImportedInstDecls gates
511 = -- First, load any orphan-instance modules that aren't aready loaded
512 -- Orphan-instance modules are recorded in the module dependecnies
513 getIfacesRn `thenRn` \ ifaces ->
516 [mod | (mod, (True, _)) <- fmToList (iImpModInfo ifaces)]
518 loadOrphanModules orphan_mods `thenRn_`
520 -- Now we're ready to grab the instance declarations
521 -- Find the un-gated ones and return them,
522 -- removing them from the bag kept in Ifaces
523 getIfacesRn `thenRn` \ ifaces ->
524 getTypeEnvRn `thenRn` \ lookup ->
526 (decls, new_insts) = selectGated gates lookup (iInsts ifaces)
528 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
530 traceRn (sep [text "getImportedInstDecls:",
531 nest 4 (fsep (map ppr gate_list)),
532 text "Slurped" <+> int (length decls) <+> text "instance declarations",
533 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
536 gate_list = nameSetToList gates
538 ppr_brief_inst_decl (mod, InstDecl inst_ty _ _ _ _)
540 HsForAllTy _ _ tau -> ppr tau
543 getImportedRules :: RnMG [(Module,RdrNameRuleDecl)]
545 | opt_IgnoreIfacePragmas = returnRn []
547 = getIfacesRn `thenRn` \ ifaces ->
548 getTypeEnvRn `thenRn` \ lookup ->
550 gates = iSlurp ifaces -- Anything at all that's been slurped
551 rules = iRules ifaces
552 (decls, new_rules) = selectGated gates lookup rules
557 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
558 traceRn (sep [text "getImportedRules:",
559 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
562 selectGated gates lookup (decl_bag, n_slurped)
563 -- Select only those decls whose gates are *all* in 'gates'
564 -- or are a class in 'lookup'
566 | opt_NoPruneDecls -- Just to try the effect of not gating at all
568 decls = foldrBag (\ (_,d) ds -> d:ds) [] decl_bag -- Grab them all
570 (decls, (emptyBag, n_slurped + length decls))
574 = case foldrBag select ([], emptyBag) decl_bag of
575 (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls))
577 available n = n `elemNameSet` gates
578 || case lookup n of { Just (AClass c) -> True; other -> False }
580 select (reqd, decl) (yes, no)
581 | all available reqd = (decl:yes, no)
582 | otherwise = (yes, (reqd,decl) `consBag` no)
586 %*********************************************************
588 \subsection{Getting in a declaration}
590 %*********************************************************
593 importDecl :: Name -> RnMG ImportDeclResult
595 data ImportDeclResult
598 | HereItIs (Module, RdrNameTyClDecl)
601 = -- STEP 1: Check if we've slurped it in while compiling this module
602 getIfacesRn `thenRn` \ ifaces ->
603 if name `elemNameSet` iSlurp ifaces then
604 returnRn AlreadySlurped
607 -- STEP 2: Check if it's already in the type environment
608 getTypeEnvRn `thenRn` \ lookup ->
609 case lookup name of {
610 Just ty_thing | name `elemNameEnv` wiredInThingEnv
611 -> -- When we find a wired-in name we must load its home
612 -- module so that we find any instance decls lurking therein
613 loadHomeInterface wi_doc name `thenRn_`
614 returnRn (InTypeEnv ty_thing)
617 -> returnRn (InTypeEnv ty_thing) ;
621 -- STEP 3: OK, we have to slurp it in from an interface file
622 -- First load the interface file
623 traceRn nd_doc `thenRn_`
624 loadHomeInterface nd_doc name `thenRn_`
625 getIfacesRn `thenRn` \ ifaces ->
627 -- STEP 4: Get the declaration out
629 (decls_map, _) = iDecls ifaces
631 case lookupNameEnv decls_map name of
633 -> setIfacesRn (recordSlurp ifaces avail) `thenRn_`
634 returnRn (HereItIs decl)
637 -> addErrRn (getDeclErr name) `thenRn_`
638 returnRn AlreadySlurped
641 wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name
642 nd_doc = ptext SLIT("need decl for") <+> ppr name
647 %********************************************************
649 \subsection{Checking usage information}
651 %********************************************************
653 @recompileRequired@ is called from the HscMain. It checks whether
654 a recompilation is required. It needs access to the persistent state,
655 finder, etc, because it may have to load lots of interface files to
656 check their versions.
659 type RecompileRequired = Bool
660 upToDate = False -- Recompile not required
661 outOfDate = True -- Recompile required
663 recompileRequired :: FilePath -- Only needed for debug msgs
664 -> Bool -- Source unchanged
665 -> ModIface -- Old interface
666 -> RnMG RecompileRequired
667 recompileRequired iface_path source_unchanged iface
668 = traceHiDiffsRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_`
670 -- CHECK WHETHER THE SOURCE HAS CHANGED
671 if not source_unchanged then
672 traceHiDiffsRn (nest 4 (text "Source file changed or recompilation check turned off")) `thenRn_`
676 -- Source code unchanged and no errors yet... carry on
677 checkList [checkModUsage u | u <- mi_usages iface]
679 checkList :: [RnMG RecompileRequired] -> RnMG RecompileRequired
680 checkList [] = returnRn upToDate
681 checkList (check:checks) = check `thenRn` \ recompile ->
689 checkModUsage :: ImportVersion Name -> RnMG RecompileRequired
690 -- Given the usage information extracted from the old
691 -- M.hi file for the module being compiled, figure out
692 -- whether M needs to be recompiled.
694 checkModUsage (mod_name, _, _, NothingAtAll)
695 -- If CurrentModule.hi contains
697 -- then that simply records that Foo lies below CurrentModule in the
698 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
699 -- In this case we don't even want to open Foo's interface.
700 = up_to_date (ptext SLIT("Nothing used from:") <+> ppr mod_name)
702 checkModUsage (mod_name, _, is_boot, whats_imported)
703 = -- Load the imported interface is possible
704 -- We use tryLoadInterface, because failure is not an error
705 -- (might just be that the old .hi file for this module is out of date)
706 -- We use ImportByUser/ImportByUserSource as the 'from' flag,
707 -- a) because we need to know whether to load the .hi-boot file
708 -- b) because loadInterface things matters are amiss if we
709 -- ImportBySystem an interface it knows nothing about
711 doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
712 from | is_boot = ImportByUserSource
713 | otherwise = ImportByUser
715 tryLoadInterface doc_str mod_name from `thenRn` \ (iface, maybe_err) ->
718 Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"),
720 -- Couldn't find or parse a module mentioned in the
721 -- old interface file. Don't complain -- it might just be that
722 -- the current module doesn't need that import and it's been deleted
726 new_vers = mi_version iface
727 new_decl_vers = vers_decls new_vers
729 case whats_imported of { -- NothingAtAll dealt with earlier
731 Everything old_mod_vers -> checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
733 out_of_date (ptext SLIT("...and I needed the whole module"))
737 Specifically old_mod_vers maybe_old_export_vers old_decl_vers old_rule_vers ->
740 checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
741 if not recompile then
746 if checkExportList maybe_old_export_vers new_vers then
747 out_of_date (ptext SLIT("Export list changed"))
751 if old_rule_vers /= vers_rules new_vers then
752 out_of_date (ptext SLIT("Rules changed"))
755 -- CHECK ITEMS ONE BY ONE
756 checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenRn` \ recompile ->
758 returnRn outOfDate -- This one failed, so just bail out now
760 up_to_date (ptext SLIT("...but the bits I use haven't."))
764 ------------------------
765 checkModuleVersion old_mod_vers new_vers
766 | vers_module new_vers == old_mod_vers
767 = up_to_date (ptext SLIT("Module version unchanged"))
770 = out_of_date (ptext SLIT("Module version has changed"))
772 ------------------------
773 checkExportList Nothing new_vers = upToDate
774 checkExportList (Just v) new_vers = v /= vers_exports new_vers
776 ------------------------
777 checkEntityUsage new_vers (name,old_vers)
778 = case lookupNameEnv new_vers name of
780 Nothing -> -- We used it before, but it ain't there now
781 out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
783 Just new_vers -- It's there, but is it up to date?
784 | new_vers == old_vers -> returnRn upToDate
785 | otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
787 up_to_date msg = traceHiDiffsRn msg `thenRn_` returnRn upToDate
788 out_of_date msg = traceHiDiffsRn msg `thenRn_` returnRn outOfDate
792 %*********************************************************
796 %*********************************************************
800 = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
801 ptext SLIT("from module") <+> quotes (ppr (nameModule name))