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, isModuleInThisPackage,
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 getImportVersions figures out what the ``usage information'' for this
89 moudule is; that is, what it must record in its interface file as the
90 things it uses. It records:
93 \item (a) anything reachable from its body code
94 \item (b) any module exported with a @module Foo@
95 \item (c) anything reachable from an exported item
98 Why (b)? Because if @Foo@ changes then this module's export list
99 will change, so we must recompile this module at least as far as
100 making a new interface file --- but in practice that means complete
103 Why (c)? Consider this:
105 module A( f, g ) where | module B( f ) where
106 import B( f ) | f = h 3
110 Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
111 @A@'s usages? Our idea is that we aren't going to touch A.hi if it is
112 *identical* to what it was before. If anything about @B.f@ changes
113 than anyone who imports @A@ should be recompiled in case they use
114 @B.f@ (they'll get an early exit if they don't). So, if anything
115 about @B.f@ changes we'd better make sure that something in A.hi
116 changes, and the convenient way to do that is to record the version
117 number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
118 complete recompiation of A, which is overkill but it's the only way to
119 write a new, slightly different, A.hi.
121 But the example is tricker. Even if @B.f@ doesn't change at all,
122 @B.h@ may do so, and this change may not be reflected in @f@'s version
123 number. But with -O, a module that imports A must be recompiled if
124 @B.h@ changes! So A must record a dependency on @B.h@. So we treat
125 the occurrence of @B.f@ in the export list *just as if* it were in the
126 code of A, and thereby haul in all the stuff reachable from it.
128 [NB: If B was compiled with -O, but A isn't, we should really *still*
129 haul in all the unfoldings for B, in case the module that imports A *is*
130 compiled with -O. I think this is the case.]
132 Even if B is used at all we get a usage line for B
133 import B <n> :: ... ;
134 in A.hi, to record the fact that A does import B. This is used to decide
135 to look to look for B.hi rather than B.hi-boot when compiling a module that
136 imports A. This line says that A imports B, but uses nothing in it.
137 So we'll get an early bale-out when compiling A if B's version changes.
140 mkImportInfo :: ModuleName -- Name of this module
141 -> [ImportDecl n] -- The import decls
142 -> RnMG [ImportVersion Name]
144 mkImportInfo this_mod imports
145 = getIfacesRn `thenRn` \ ifaces ->
146 getHomeIfaceTableRn `thenRn` \ hit ->
148 (imp_pkg_mods, imp_home_names) = iVSlurp ifaces
151 import_all_mods :: [ModuleName]
152 -- Modules where we imported all the names
153 -- (apart from hiding some, perhaps)
154 import_all_mods = [ m | ImportDecl m _ _ _ imp_list _ <- imports,
155 import_all imp_list ]
157 import_all (Just (False, _)) = False -- Imports are specified explicitly
158 import_all other = True -- Everything is imported
160 -- mv_map groups together all the things imported and used
161 -- from a particular module in this package
162 -- We use a finite map because we want the domain
163 mv_map :: ModuleEnv [Name]
164 mv_map = foldNameSet add_mv emptyModuleEnv imp_home_names
165 add_mv name mv_map = extendModuleEnv_C add_item mv_map mod [name]
167 mod = nameModule name
168 add_item names _ = name:names
170 -- In our usage list we record
171 -- a) Specifically: Detailed version info for imports from modules in this package
172 -- Gotten from iVSlurp plus import_all_mods
174 -- b) Everything: Just the module version for imports from modules in other packages
175 -- Gotten from iVSlurp plus import_all_mods
177 -- c) NothingAtAll: The name only of modules, Baz, in this package that are 'below' us,
178 -- but which we didn't need at all (this is needed only to decide whether
179 -- to open Baz.hi or Baz.hi-boot higher up the tree).
180 -- This happens when a module, Foo, that we explicitly imported has
181 -- 'import Baz' in its interface file, recording that Baz is below
182 -- Foo in the module dependency hierarchy. We want to propagate this info.
183 -- These modules are in a combination of HIT/PIT and iImpModInfo
185 -- d) NothingAtAll: The name only of all orphan modules we know of (this is needed
186 -- so that anyone who imports us can find the orphan modules)
187 -- These modules are in a combination of HIT/PIT and iImpModInfo
189 import_info0 = foldModuleEnv mk_imp_info [] pit
190 import_info1 = foldModuleEnv mk_imp_info import_info0 hit
191 import_info = [ (mod_name, orphans, is_boot, NothingAtAll)
192 | (mod_name, (orphans, is_boot)) <- fmToList (iImpModInfo ifaces) ] ++
195 mk_imp_info :: ModIface -> [ImportVersion Name] -> [ImportVersion Name]
196 mk_imp_info iface so_far
198 | Just ns <- lookupModuleEnv mv_map mod -- Case (a)
199 = go_for_it (Specifically mod_vers maybe_export_vers
200 (mk_import_items ns) rules_vers)
202 | mod `elemModuleSet` imp_pkg_mods -- Case (b)
203 = go_for_it (Everything mod_vers)
205 | import_all_mod -- Case (a) and (b); the import-all part
206 = if is_home_pkg_mod then
207 go_for_it (Specifically mod_vers (Just export_vers) [] rules_vers)
209 go_for_it (Everything mod_vers)
211 | is_home_pkg_mod || has_orphans -- Case (c) or (d)
212 = go_for_it NothingAtAll
216 go_for_it exports = (mod_name, has_orphans, mi_boot iface, exports) : so_far
218 mod = mi_module iface
219 mod_name = moduleName mod
220 is_home_pkg_mod = isModuleInThisPackage mod
221 version_info = mi_version iface
222 version_env = vers_decls version_info
223 mod_vers = vers_module version_info
224 rules_vers = vers_rules version_info
225 export_vers = vers_exports version_info
226 import_all_mod = mod_name `elem` import_all_mods
227 has_orphans = mi_orphan iface
229 -- The sort is to put them into canonical order
230 mk_import_items ns = [(n,v) | n <- sortLt lt_occ ns,
231 let v = lookupNameEnv version_env n `orElse`
232 pprPanic "mk_whats_imported" (ppr n)
235 lt_occ n1 n2 = nameOccName n1 < nameOccName n2
237 maybe_export_vers | import_all_mod = Just (vers_exports version_info)
238 | otherwise = Nothing
243 %*********************************************************
245 \subsection{Slurping declarations}
247 %*********************************************************
250 -------------------------------------------------------
251 slurpImpDecls source_fvs
252 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
254 -- The current slurped-set records all local things
255 getSlurped `thenRn` \ source_binders ->
256 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
258 -- Then get everything else
259 closeDecls decls needed
262 -------------------------------------------------------
263 slurpSourceRefs :: NameSet -- Variables defined in source
264 -> FreeVars -- Variables referenced in source
265 -> RnMG ([RenamedHsDecl],
266 FreeVars) -- Un-satisfied needs
267 -- The declaration (and hence home module) of each gate has
268 -- already been loaded
270 slurpSourceRefs source_binders source_fvs
271 = go_outer [] -- Accumulating decls
272 emptyFVs -- Unsatisfied needs
273 emptyFVs -- Accumulating gates
274 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
276 -- The outer loop repeatedly slurps the decls for the current gates
277 -- and the instance decls
279 -- The outer loop is needed because consider
281 go_outer decls fvs all_gates []
282 = returnRn (decls, fvs)
284 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
285 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
286 getImportedInstDecls all_gates `thenRn` \ inst_decls ->
287 foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
288 rnIfaceInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
289 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
290 (nameSetToList (gates2 `minusNameSet` all_gates))
291 -- Knock out the all_gates because even if we don't slurp any new
292 -- decls we can get some apparently-new gates from wired-in names
294 go_inner (decls, fvs, gates) wanted_name
295 = importDecl wanted_name `thenRn` \ import_result ->
296 case import_result of
297 AlreadySlurped -> returnRn (decls, fvs, gates)
298 InTypeEnv ty_thing -> returnRn (decls, fvs, gates `plusFV` getWiredInGates ty_thing)
300 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
301 returnRn (TyClD new_decl : decls,
303 gates `plusFV` getGates source_fvs new_decl)
308 -------------------------------------------------------
309 -- closeDecls keeps going until the free-var set is empty
310 closeDecls decls needed
311 | not (isEmptyFVs needed)
312 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
313 closeDecls decls1 needed1
316 = getImportedRules `thenRn` \ rule_decls ->
318 [] -> returnRn decls -- No new rules, so we are done
319 other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' ->
320 closeDecls (map RuleD rule_decls' ++ decls)
321 (plusFVs (map ruleDeclFVs rule_decls'))
324 -------------------------------------------------------
325 -- Augment decls with any decls needed by needed.
326 -- Return also free vars of the new decls (only)
327 slurpDecls decls needed
328 = go decls emptyFVs (nameSetToList needed)
330 go decls fvs [] = returnRn (decls, fvs)
331 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
334 -------------------------------------------------------
335 slurpDecl decls fvs wanted_name
336 = importDecl wanted_name `thenRn` \ import_result ->
337 case import_result of
338 -- Found a declaration... rename it
339 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
340 returnRn (TyClD new_decl:decls, fvs1 `plusFV` fvs)
342 -- No declaration... (wired in thing, or deferred, or already slurped)
343 other -> returnRn (decls, fvs)
346 -------------------------------------------------------
347 rnIfaceDecls rn decls = mapRn (rnIfaceDecl rn) decls
348 rnIfaceDecl rn (mod, decl) = initIfaceRnMS mod (rn decl)
350 rnIfaceInstDecls decls fvs gates inst_decls
351 = rnIfaceDecls rnInstDecl inst_decls `thenRn` \ inst_decls' ->
352 returnRn (map InstD inst_decls' ++ decls,
353 fvs `plusFV` plusFVs (map instDeclFVs inst_decls'),
354 gates `plusFV` plusFVs (map getInstDeclGates inst_decls'))
356 rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl) `thenRn` \ decl' ->
357 returnRn (decl', tyClDeclFVs decl')
363 = getIfacesRn `thenRn` \ ifaces ->
364 returnRn (iSlurp ifaces)
366 recordSlurp ifaces@(Ifaces { iDecls = (decls_map, n_slurped),
367 iSlurp = slurped_names,
368 iVSlurp = (imp_mods, imp_names) })
370 = ASSERT2( not (isLocalName (availName avail)), ppr avail )
371 ifaces { iDecls = (decls_map', n_slurped+1),
372 iSlurp = new_slurped_names,
373 iVSlurp = new_vslurp }
375 decls_map' = foldl delFromNameEnv decls_map (availNames avail)
376 main_name = availName avail
377 mod = nameModule main_name
378 new_slurped_names = addAvailToNameSet slurped_names avail
379 new_vslurp | isModuleInThisPackage mod = (imp_mods, addOneToNameSet imp_names main_name)
380 | otherwise = (extendModuleSet imp_mods mod, imp_names)
382 recordLocalSlurps local_avails
383 = getIfacesRn `thenRn` \ ifaces ->
385 new_slurped_names = foldl addAvailToNameSet (iSlurp ifaces) local_avails
387 setIfacesRn (ifaces { iSlurp = new_slurped_names })
392 %*********************************************************
394 \subsection{Extracting the `gates'}
396 %*********************************************************
400 We want to avoid sucking in too many instance declarations.
401 An instance decl is only useful if the types and classes mentioned in
402 its 'head' are all available in the program being compiled. E.g.
404 instance (..) => C (T1 a) (T2 b) where ...
406 is only useful if C, T1 and T2 are all "available". So we keep
407 instance decls that have been parsed from .hi files, but not yet
408 slurped in, in a pool called the 'gated instance pool'.
409 Each has its set of 'gates': {C, T1, T2} in the above example.
411 More precisely, the gates of a module are the types and classes
412 that are mentioned in:
415 b) the type of an Id that's mentioned in the source code
416 [includes constructors and selectors]
417 c) the RHS of a type synonym that is a gate
418 d) the superclasses of a class that is a gate
419 e) the context of an instance decl that is slurped in
421 We slurp in an instance decl from the gated instance pool iff
423 all its gates are either in the gates of the module,
424 or are a previously-loaded class.
426 The latter constraint is because there might have been an instance
427 decl slurped in during an earlier compilation, like this:
429 instance Foo a => Baz (Maybe a) where ...
431 In the module being compiled we might need (Baz (Maybe T)), where T
432 is defined in this module, and hence we need (Foo T). So @Foo@ becomes
433 a gate. But there's no way to 'see' that, so we simply treat all
434 previously-loaded classes as gates.
436 Consructors and class operations
437 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
438 When we import a declaration like
440 data T = T1 Wibble | T2 Wobble
442 we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless}
443 @T1@, @T2@ respectively are mentioned by the user program. If only
444 @T@ is mentioned we want only @T@ to be a gate; that way we don't suck
445 in useless instance decls for (say) @Eq Wibble@, when they can't
448 And that's just what (b) says: we only treat T1's type as a gate if
449 T1 is mentioned. getGates, which deals with decls we are slurping in,
450 has to be a bit careful, because a mention of T1 will slurp in T's whole
453 -----------------------------
454 @getGates@ takes a newly imported (and renamed) decl, and the free
455 vars of the source program, and extracts from the decl the gate names.
458 getGates :: FreeVars -- Things mentioned in the source program
462 getGates source_fvs decl
463 = get_gates (\n -> n `elemNameSet` source_fvs) decl
465 get_gates is_used (IfaceSig _ ty _ _)
466 = extractHsTyNames ty
468 get_gates is_used (ClassDecl ctxt cls tvs _ sigs _ _ _ )
469 = (delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
471 `addOneToNameSet` cls)
472 `plusFV` maybe_double
474 get (ClassOpSig n _ ty _)
475 | is_used n = extractHsTyNames ty
476 | otherwise = emptyFVs
478 -- If we load any numeric class that doesn't have
479 -- Int as an instance, add Double to the gates.
480 -- This takes account of the fact that Double might be needed for
481 -- defaulting, but we don't want to load Double (and all its baggage)
482 -- if the more exotic classes aren't used at all.
483 maybe_double | nameUnique cls `elem` fractionalClassKeys
484 = unitFV (getName doubleTyCon)
488 get_gates is_used (TySynonym tycon tvs ty _)
489 = delListFromNameSet (extractHsTyNames ty) (hsTyVarNames tvs)
490 -- A type synonym type constructor isn't a "gate" for instance decls
492 get_gates is_used (TyData _ ctxt tycon tvs cons _ _ _ _ _)
493 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
495 `addOneToNameSet` tycon
497 get (ConDecl n _ tvs ctxt details _)
499 -- If the constructor is method, get fvs from all its fields
500 = delListFromNameSet (get_details details `plusFV`
501 extractHsCtxtTyNames ctxt)
503 get (ConDecl n _ tvs ctxt (RecCon fields) _)
504 -- Even if the constructor isn't mentioned, the fields
505 -- might be, as selectors. They can't mention existentially
506 -- bound tyvars (typechecker checks for that) so no need for
507 -- the deleteListFromNameSet part
508 = foldr (plusFV . get_field) emptyFVs fields
510 get other_con = emptyFVs
512 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
513 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
514 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
516 get_field (fs,t) | any is_used fs = get_bang t
517 | otherwise = emptyFVs
519 get_bang bty = extractHsTyNames (getBangType bty)
522 @getWiredInGates@ is just like @getGates@, but it sees a previously-loaded
523 thing rather than a declaration.
526 getWiredInGates :: TyThing -> FreeVars
527 -- The TyThing is one that we already have in our type environment, either
528 -- a) because the TyCon or Id is wired in, or
529 -- b) from a previous compile
530 -- Either way, we might have instance decls in the (persistent) collection
531 -- of parsed-but-not-slurped instance decls that should be slurped in.
532 -- This might be the first module that mentions both the type and the class
533 -- for that instance decl, even though both the type and the class were
534 -- mentioned in other modules, and hence are in the type environment
536 getWiredInGates (AnId the_id) = namesOfType (idType the_id)
537 getWiredInGates (AClass cl) = emptyFVs -- The superclasses must also be previously
538 -- loaded, and hence are automatically gates
539 getWiredInGates (ATyCon tc)
540 | isSynTyCon tc = delListFromNameSet (namesOfType ty) (map getName tyvars)
541 | otherwise = unitFV (getName tc)
543 (tyvars,ty) = getSynTyConDefn tc
545 getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty
549 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameInstDecl)]
550 getImportedInstDecls gates
551 = -- First, load any orphan-instance modules that aren't aready loaded
552 -- Orphan-instance modules are recorded in the module dependecnies
553 getIfacesRn `thenRn` \ ifaces ->
556 [mod | (mod, (True, _)) <- fmToList (iImpModInfo ifaces)]
558 loadOrphanModules orphan_mods `thenRn_`
560 -- Now we're ready to grab the instance declarations
561 -- Find the un-gated ones and return them,
562 -- removing them from the bag kept in Ifaces
563 getIfacesRn `thenRn` \ ifaces ->
564 getTypeEnvRn `thenRn` \ lookup ->
566 (decls, new_insts) = selectGated gates lookup (iInsts ifaces)
568 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
570 traceRn (sep [text "getImportedInstDecls:",
571 nest 4 (fsep (map ppr gate_list)),
572 text "Slurped" <+> int (length decls) <+> text "instance declarations",
573 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
576 gate_list = nameSetToList gates
578 ppr_brief_inst_decl (mod, InstDecl inst_ty _ _ _ _)
580 HsForAllTy _ _ tau -> ppr tau
583 getImportedRules :: RnMG [(Module,RdrNameRuleDecl)]
585 | opt_IgnoreIfacePragmas = returnRn []
587 = getIfacesRn `thenRn` \ ifaces ->
588 getTypeEnvRn `thenRn` \ lookup ->
590 gates = iSlurp ifaces -- Anything at all that's been slurped
591 rules = iRules ifaces
592 (decls, new_rules) = selectGated gates lookup rules
597 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
598 traceRn (sep [text "getImportedRules:",
599 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
602 selectGated gates lookup (decl_bag, n_slurped)
603 -- Select only those decls whose gates are *all* in 'gates'
604 -- or are a class in 'lookup'
606 | opt_NoPruneDecls -- Just to try the effect of not gating at all
608 decls = foldrBag (\ (_,d) ds -> d:ds) [] decl_bag -- Grab them all
610 (decls, (emptyBag, n_slurped + length decls))
614 = case foldrBag select ([], emptyBag) decl_bag of
615 (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls))
617 available n = n `elemNameSet` gates
618 || case lookup n of { Just (AClass c) -> True; other -> False }
620 select (reqd, decl) (yes, no)
621 | all available reqd = (decl:yes, no)
622 | otherwise = (yes, (reqd,decl) `consBag` no)
626 %*********************************************************
628 \subsection{Getting in a declaration}
630 %*********************************************************
633 importDecl :: Name -> RnMG ImportDeclResult
635 data ImportDeclResult
638 | HereItIs (Module, RdrNameTyClDecl)
641 = -- STEP 1: Check if it was loaded before beginning this module
642 if isLocalName name then
643 traceRn (text "Already (local)" <+> ppr name) `thenRn_`
644 returnRn AlreadySlurped
647 -- STEP 2: Check if it's already in the type environment
648 getTypeEnvRn `thenRn` \ lookup ->
649 case lookup name of {
650 Just ty_thing | name `elemNameEnv` wiredInThingEnv
651 -> -- When we find a wired-in name we must load its home
652 -- module so that we find any instance decls lurking therein
653 loadHomeInterface wi_doc name `thenRn_`
654 returnRn (InTypeEnv ty_thing)
657 -> returnRn (InTypeEnv ty_thing) ;
661 -- STEP 3: Check if we've slurped it in while compiling this module
662 getIfacesRn `thenRn` \ ifaces ->
663 if name `elemNameSet` iSlurp ifaces then
664 returnRn AlreadySlurped
667 -- STEP 4: OK, we have to slurp it in from an interface file
668 -- First load the interface file
669 traceRn nd_doc `thenRn_`
670 loadHomeInterface nd_doc name `thenRn_`
671 getIfacesRn `thenRn` \ ifaces ->
673 -- STEP 5: Get the declaration out
675 (decls_map, _) = iDecls ifaces
677 case lookupNameEnv decls_map name of
679 -> setIfacesRn (recordSlurp ifaces avail) `thenRn_`
680 returnRn (HereItIs decl)
683 -> addErrRn (getDeclErr name) `thenRn_`
684 returnRn AlreadySlurped
687 wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name
688 nd_doc = ptext SLIT("need decl for") <+> ppr name
693 %********************************************************
695 \subsection{Checking usage information}
697 %********************************************************
699 @recompileRequired@ is called from the HscMain. It checks whether
700 a recompilation is required. It needs access to the persistent state,
701 finder, etc, because it may have to load lots of interface files to
702 check their versions.
705 type RecompileRequired = Bool
706 upToDate = False -- Recompile not required
707 outOfDate = True -- Recompile required
709 recompileRequired :: FilePath -- Only needed for debug msgs
710 -> Bool -- Source unchanged
711 -> ModIface -- Old interface
712 -> RnMG RecompileRequired
713 recompileRequired iface_path source_unchanged iface
714 = traceRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_`
716 -- CHECK WHETHER THE SOURCE HAS CHANGED
717 if not source_unchanged then
718 traceRn (nest 4 (text "Source file changed or recompilation check turned off")) `thenRn_`
722 -- Source code unchanged and no errors yet... carry on
723 checkList [checkModUsage u | u <- mi_usages iface]
725 checkList :: [RnMG RecompileRequired] -> RnMG RecompileRequired
726 checkList [] = returnRn upToDate
727 checkList (check:checks) = check `thenRn` \ recompile ->
735 checkModUsage :: ImportVersion Name -> RnMG RecompileRequired
736 -- Given the usage information extracted from the old
737 -- M.hi file for the module being compiled, figure out
738 -- whether M needs to be recompiled.
740 checkModUsage (mod_name, _, _, NothingAtAll)
741 -- If CurrentModule.hi contains
743 -- then that simply records that Foo lies below CurrentModule in the
744 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
745 -- In this case we don't even want to open Foo's interface.
746 = up_to_date (ptext SLIT("Nothing used from:") <+> ppr mod_name)
748 checkModUsage (mod_name, _, _, whats_imported)
749 = tryLoadInterface doc_str mod_name ImportBySystem `thenRn` \ (iface, maybe_err) ->
751 Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"),
753 -- Couldn't find or parse a module mentioned in the
754 -- old interface file. Don't complain -- it might just be that
755 -- the current module doesn't need that import and it's been deleted
759 new_vers = mi_version iface
760 new_decl_vers = vers_decls new_vers
762 case whats_imported of { -- NothingAtAll dealt with earlier
764 Everything old_mod_vers -> checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
766 out_of_date (ptext SLIT("...and I needed the whole module"))
770 Specifically old_mod_vers maybe_old_export_vers old_decl_vers old_rule_vers ->
773 checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
774 if not recompile then
779 if checkExportList maybe_old_export_vers new_vers then
780 out_of_date (ptext SLIT("Export list changed"))
784 if old_rule_vers /= vers_rules new_vers then
785 out_of_date (ptext SLIT("Rules changed"))
788 -- CHECK ITEMS ONE BY ONE
789 checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenRn` \ recompile ->
791 returnRn outOfDate -- This one failed, so just bail out now
793 up_to_date (ptext SLIT("...but the bits I use haven't."))
797 doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
799 ------------------------
800 checkModuleVersion old_mod_vers new_vers
801 | vers_module new_vers == old_mod_vers
802 = up_to_date (ptext SLIT("Module version unchanged"))
805 = out_of_date (ptext SLIT("Module version has changed"))
807 ------------------------
808 checkExportList Nothing new_vers = upToDate
809 checkExportList (Just v) new_vers = v /= vers_exports new_vers
811 ------------------------
812 checkEntityUsage new_vers (name,old_vers)
813 = case lookupNameEnv new_vers name of
815 Nothing -> -- We used it before, but it ain't there now
816 out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
818 Just new_vers -- It's there, but is it up to date?
819 | new_vers == old_vers -> returnRn upToDate
820 | otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
822 up_to_date msg = traceRn msg `thenRn_` returnRn upToDate
823 out_of_date msg = traceRn msg `thenRn_` returnRn outOfDate
827 %*********************************************************
831 %*********************************************************
835 = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
836 ptext SLIT("from module") <+> quotes (ppr (nameModule name))