2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnIfaces]{Cacheing and Renaming of Interfaces}
15 RecompileRequired, outOfDate, upToDate, recompileRequired
19 #include "HsVersions.h"
21 import CmdLineOpts ( DynFlags, opt_NoPruneDecls, opt_NoPruneTyDecls, opt_IgnoreIfacePragmas )
23 import HsSyn ( HsDecl(..), InstDecl(..), HsType(..) )
24 import HsImpExp ( ImportDecl(..) )
25 import BasicTypes ( Version, defaultFixity )
26 import RdrHsSyn ( RdrNameHsDecl, RdrNameTyClDecl, RdrNameInstDecl )
27 import RnHiFiles ( tryLoadInterface, loadHomeInterface, loadInterface,
30 import RnSource ( rnTyClDecl, rnDecl )
33 import Name ( Name {-instance NamedThing-}, nameOccName,
34 nameModule, isLocallyDefined,
38 import Module ( Module, ModuleEnv,
39 moduleName, isModuleInThisPackage,
40 ModuleName, WhereFrom(..),
41 emptyModuleEnv, lookupModuleEnvByName,
42 extendModuleEnv_C, lookupWithDefaultModuleEnv
45 import PrelInfo ( wiredInThingEnv )
46 import Maybes ( orElse )
55 %*********************************************************
57 \subsection{Getting what a module exports}
59 %*********************************************************
61 @getInterfaceExports@ is called only for directly-imported modules.
64 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
65 getInterfaceExports mod_name from
66 = getHomeIfaceTableRn `thenRn` \ hit ->
67 case lookupModuleEnvByName hit mod_name of {
68 Just mi -> returnRn (mi_module mi, mi_exports mi) ;
71 loadInterface doc_str mod_name from `thenRn` \ ifaces ->
72 case lookupModuleEnvByName (iPIT ifaces) mod_name of
73 Just mi -> returnRn (mi_module mi, mi_exports mi) ;
74 -- loadInterface always puts something in the map
75 -- even if it's a fake
76 Nothing -> pprPanic "getInterfaceExports" (ppr mod_name)
79 doc_str = sep [ppr mod_name, ptext SLIT("is directly imported")]
83 %*********************************************************
85 \subsection{Instance declarations are handled specially}
87 %*********************************************************
90 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
91 getImportedInstDecls gates
92 = -- First, load any orphan-instance modules that aren't aready loaded
93 -- Orphan-instance modules are recorded in the module dependecnies
94 getIfacesRn `thenRn` \ ifaces ->
97 [mod | (mod, (True, _, False)) <- fmToList (iImpModInfo ifaces)]
99 loadOrphanModules orphan_mods `thenRn_`
101 -- Now we're ready to grab the instance declarations
102 -- Find the un-gated ones and return them,
103 -- removing them from the bag kept in Ifaces
104 getIfacesRn `thenRn` \ ifaces ->
106 (decls, new_insts) = selectGated gates (iInsts ifaces)
108 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
110 traceRn (sep [text "getImportedInstDecls:",
111 nest 4 (fsep (map ppr gate_list)),
112 text "Slurped" <+> int (length decls) <+> text "instance declarations",
113 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
116 gate_list = nameSetToList gates
118 ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
120 HsForAllTy _ _ tau -> ppr tau
123 getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
125 | opt_IgnoreIfacePragmas = returnRn []
127 = getIfacesRn `thenRn` \ ifaces ->
129 gates = iSlurp ifaces -- Anything at all that's been slurped
130 rules = iRules ifaces
131 (decls, new_rules) = selectGated gates rules
136 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
137 traceRn (sep [text "getImportedRules:",
138 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
141 selectGated gates decl_bag
142 -- Select only those decls whose gates are *all* in 'gates'
144 | opt_NoPruneDecls -- Just to try the effect of not gating at all
145 = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
149 = foldrBag select ([], emptyBag) decl_bag
151 select (reqd, decl) (yes, no)
152 | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
153 | otherwise = (yes, (reqd,decl) `consBag` no)
157 %*********************************************************
159 \subsection{Keeping track of what we've slurped, and version numbers}
161 %*********************************************************
163 getImportVersions figures out what the ``usage information'' for this
164 moudule is; that is, what it must record in its interface file as the
165 things it uses. It records:
168 \item (a) anything reachable from its body code
169 \item (b) any module exported with a @module Foo@
170 \item (c) anything reachable from an exported item
173 Why (b)? Because if @Foo@ changes then this module's export list
174 will change, so we must recompile this module at least as far as
175 making a new interface file --- but in practice that means complete
178 Why (c)? Consider this:
180 module A( f, g ) where | module B( f ) where
181 import B( f ) | f = h 3
185 Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
186 @A@'s usages? Our idea is that we aren't going to touch A.hi if it is
187 *identical* to what it was before. If anything about @B.f@ changes
188 than anyone who imports @A@ should be recompiled in case they use
189 @B.f@ (they'll get an early exit if they don't). So, if anything
190 about @B.f@ changes we'd better make sure that something in A.hi
191 changes, and the convenient way to do that is to record the version
192 number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
193 complete recompiation of A, which is overkill but it's the only way to
194 write a new, slightly different, A.hi.
196 But the example is tricker. Even if @B.f@ doesn't change at all,
197 @B.h@ may do so, and this change may not be reflected in @f@'s version
198 number. But with -O, a module that imports A must be recompiled if
199 @B.h@ changes! So A must record a dependency on @B.h@. So we treat
200 the occurrence of @B.f@ in the export list *just as if* it were in the
201 code of A, and thereby haul in all the stuff reachable from it.
203 [NB: If B was compiled with -O, but A isn't, we should really *still*
204 haul in all the unfoldings for B, in case the module that imports A *is*
205 compiled with -O. I think this is the case.]
207 Even if B is used at all we get a usage line for B
208 import B <n> :: ... ;
209 in A.hi, to record the fact that A does import B. This is used to decide
210 to look to look for B.hi rather than B.hi-boot when compiling a module that
211 imports A. This line says that A imports B, but uses nothing in it.
212 So we'll get an early bale-out when compiling A if B's version changes.
215 mkImportInfo :: ModuleName -- Name of this module
216 -> [ImportDecl n] -- The import decls
217 -> RnMG [ImportVersion Name]
219 mkImportInfo this_mod imports
220 = getIfacesRn `thenRn` \ ifaces ->
221 getHomeIfaceTableRn `thenRn` \ hit ->
223 import_all_mods :: [ModuleName]
224 -- Modules where we imported all the names
225 -- (apart from hiding some, perhaps)
226 import_all_mods = nub [ m | ImportDecl m _ _ _ imp_list _ <- imports,
227 import_all imp_list ]
229 import_all (Just (False, _)) = False -- Imports are specified explicitly
230 import_all other = True -- Everything is imported
232 mod_map = iImpModInfo ifaces
233 imp_names = iVSlurp ifaces
236 -- mv_map groups together all the things imported from a particular module.
237 mv_map :: ModuleEnv [Name]
238 mv_map = foldr add_mv emptyModuleEnv imp_names
240 add_mv name mv_map = addItem mv_map (nameModule name) name
242 -- Build the result list by adding info for each module.
243 -- For (a) a library module, we don't record it at all unless it contains orphans
244 -- (We must never lose track of orphans.)
246 -- (b) a source-imported module, don't record the dependency at all
248 -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
249 -- *all* the module's dependencies other than the loop-breakers. We use
250 -- this info in findAndReadInterface to decide whether to look for a .hi file or
253 -- This means we won't track version changes, or orphans, from .hi-boot files.
254 -- The former is potentially rather bad news. It could be fixed by recording
255 -- whether something is a boot file along with the usage info for it, but
256 -- I can't be bothered just now.
258 mk_imp_info mod_name (has_orphans, is_boot, opened) so_far
259 | mod_name == this_mod -- Check if M appears in the set of modules 'below' M
260 -- This seems like a convenient place to check
261 = WARN( not is_boot, ptext SLIT("Wierd:") <+> ppr this_mod <+>
262 ptext SLIT("imports itself (perhaps indirectly)") )
265 | not opened -- We didn't even open the interface
266 = -- This happens when a module, Foo, that we explicitly imported has
267 -- 'import Baz' in its interface file, recording that Baz is below
268 -- Foo in the module dependency hierarchy. We want to propagate this
269 -- information. The Nothing says that we didn't even open the interface
270 -- file but we must still propagate the dependency info.
271 -- The module in question must be a local module (in the same package)
272 go_for_it NothingAtAll
275 | is_lib_module && not has_orphans
278 | is_lib_module -- Record the module version only
279 = go_for_it (Everything module_vers)
282 = go_for_it whats_imported
285 go_for_it exports = (mod_name, has_orphans, is_boot, exports) : so_far
286 mod_iface = lookupTableByModName hit pit mod_name `orElse` panic "mkImportInfo"
287 mod = mi_module mod_iface
288 is_lib_module = not (isModuleInThisPackage mod)
289 version_info = mi_version mod_iface
290 version_env = vers_decls version_info
291 module_vers = vers_module version_info
293 whats_imported = Specifically module_vers
294 export_vers import_items
295 (vers_rules version_info)
297 import_items = [(n,v) | n <- lookupWithDefaultModuleEnv mv_map [] mod,
298 let v = lookupNameEnv version_env n `orElse`
299 pprPanic "mk_whats_imported" (ppr n)
301 export_vers | moduleName mod `elem` import_all_mods
302 = Just (vers_exports version_info)
306 import_info = foldFM mk_imp_info [] mod_map
308 traceRn (text "Modules in Ifaces: " <+> fsep (map ppr (keysFM mod_map))) `thenRn_`
312 addItem :: ModuleEnv [a] -> Module -> a -> ModuleEnv [a]
313 addItem fm mod x = extendModuleEnv_C add_item fm mod [x]
318 %*********************************************************
320 \subsection{Slurping declarations}
322 %*********************************************************
325 -------------------------------------------------------
326 slurpImpDecls source_fvs
327 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
329 -- The current slurped-set records all local things
330 getSlurped `thenRn` \ source_binders ->
331 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
333 -- Then get everything else
334 closeDecls decls needed `thenRn` \ decls1 ->
336 -- Finally, get any deferred data type decls
337 slurpDeferredDecls decls1 `thenRn` \ final_decls ->
342 -------------------------------------------------------
343 slurpSourceRefs :: NameSet -- Variables defined in source
344 -> FreeVars -- Variables referenced in source
345 -> RnMG ([RenamedHsDecl],
346 FreeVars) -- Un-satisfied needs
347 -- The declaration (and hence home module) of each gate has
348 -- already been loaded
350 slurpSourceRefs source_binders source_fvs
351 = go_outer [] -- Accumulating decls
352 emptyFVs -- Unsatisfied needs
353 emptyFVs -- Accumulating gates
354 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
356 -- The outer loop repeatedly slurps the decls for the current gates
357 -- and the instance decls
359 -- The outer loop is needed because consider
360 -- instance Foo a => Baz (Maybe a) where ...
361 -- It may be that @Baz@ and @Maybe@ are used in the source module,
362 -- but not @Foo@; so we need to chase @Foo@ too.
364 -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
365 -- include actually getting in Foo's class decl
366 -- class Wib a => Foo a where ..
367 -- so that its superclasses are discovered. The point is that Wib is a gate too.
368 -- We do this for tycons too, so that we look through type synonyms.
370 go_outer decls fvs all_gates []
371 = returnRn (decls, fvs)
373 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
374 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
375 foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
376 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
377 rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
378 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
379 (nameSetToList (gates2 `minusNameSet` all_gates))
380 -- Knock out the all_gates because even if we don't slurp any new
381 -- decls we can get some apparently-new gates from wired-in names
383 go_inner (decls, fvs, gates) wanted_name
384 = importDecl wanted_name `thenRn` \ import_result ->
385 case import_result of
386 AlreadySlurped -> returnRn (decls, fvs, gates)
387 WiredIn -> returnRn (decls, fvs, gates `plusFV` getWiredInGates wanted_name)
388 Deferred -> returnRn (decls, fvs, gates `addOneFV` wanted_name) -- It's a type constructor
390 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
391 returnRn (TyClD new_decl : decls,
393 gates `plusFV` getGates source_fvs new_decl)
395 rnInstDecls decls fvs gates []
396 = returnRn (decls, fvs, gates)
397 rnInstDecls decls fvs gates (d:ds)
398 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
399 rnInstDecls (new_decl:decls)
401 (gates `plusFV` getInstDeclGates new_decl)
407 -------------------------------------------------------
408 -- closeDecls keeps going until the free-var set is empty
409 closeDecls decls needed
410 | not (isEmptyFVs needed)
411 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
412 closeDecls decls1 needed1
415 = getImportedRules `thenRn` \ rule_decls ->
417 [] -> returnRn decls -- No new rules, so we are done
418 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
419 closeDecls decls1 needed1
422 -------------------------------------------------------
423 -- Augment decls with any decls needed by needed.
424 -- Return also free vars of the new decls (only)
425 slurpDecls decls needed
426 = go decls emptyFVs (nameSetToList needed)
428 go decls fvs [] = returnRn (decls, fvs)
429 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
432 -------------------------------------------------------
433 slurpDecl decls fvs wanted_name
434 = importDecl wanted_name `thenRn` \ import_result ->
435 case import_result of
436 -- Found a declaration... rename it
437 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
438 returnRn (TyClD new_decl:decls, fvs1 `plusFV` fvs)
440 -- No declaration... (wired in thing, or deferred, or already slurped)
441 other -> returnRn (decls, fvs)
444 -------------------------------------------------------
445 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
446 -> [(Module, RdrNameHsDecl)]
447 -> RnM d ([RenamedHsDecl], FreeVars)
448 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
449 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
450 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
452 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
453 rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl)
459 = getIfacesRn `thenRn` \ ifaces ->
460 returnRn (iSlurp ifaces)
462 recordSlurp ifaces@(Ifaces { iSlurp = slurped_names, iVSlurp = imp_names })
465 new_slurped_names = addAvailToNameSet slurped_names avail
466 new_imp_names = availName avail : imp_names
468 ifaces { iSlurp = new_slurped_names, iVSlurp = new_imp_names }
470 recordLocalSlurps local_avails
471 = getIfacesRn `thenRn` \ ifaces ->
473 new_slurped_names = foldl addAvailToNameSet (iSlurp ifaces) local_avails
475 setIfacesRn (ifaces { iSlurp = new_slurped_names })
480 %*********************************************************
482 \subsection{Deferred declarations}
484 %*********************************************************
486 The idea of deferred declarations is this. Suppose we have a function
491 Then we don't want to load T and all its constructors, and all
492 the types those constructors refer to, and all the types *those*
493 constructors refer to, and so on. That might mean loading many more
494 interface files than is really necessary. So we 'defer' loading T.
496 But f might be strict, and the calling convention for evaluating
497 values of type T depends on how many constructors T has, so
498 we do need to load T, but not the full details of the type T.
499 So we load the full decl for T, but only skeleton decls for A and B:
501 data T = {- 2 constructors -}
503 Whether all this is worth it is moot.
506 slurpDeferredDecls :: [RenamedHsDecl] -> RnMG [RenamedHsDecl]
507 slurpDeferredDecls decls = returnRn decls
510 slurpDeferredDecls :: [RenamedHsDecl] -> RnMG [RenamedHsDecl]
511 slurpDeferredDecls decls
512 = getDeferredDecls `thenRn` \ def_decls ->
513 rnIfaceDecls decls emptyFVs (map stripDecl def_decls) `thenRn` \ (decls1, fvs) ->
514 ASSERT( isEmptyFVs fvs )
517 stripDecl (mod, TyClD (TyData dt _ tc tvs _ nconstrs _ loc name1 name2))
518 = (mod, TyClD (TyData dt [] tc tvs [] nconstrs Nothing loc
520 -- Nuke the context and constructors
521 -- But retain the *number* of constructors!
522 -- Also the tvs will have kinds on them.
527 %*********************************************************
529 \subsection{Extracting the `gates'}
531 %*********************************************************
533 When we import a declaration like
535 data T = T1 Wibble | T2 Wobble
537 we don't want to treat @Wibble@ and @Wobble@ as gates
538 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
539 If only @T@ is mentioned
540 we want only @T@ to be a gate;
541 that way we don't suck in useless instance
542 decls for (say) @Eq Wibble@, when they can't possibly be useful.
544 @getGates@ takes a newly imported (and renamed) decl, and the free
545 vars of the source program, and extracts from the decl the gate names.
548 getGates source_fvs (IfaceSig _ ty _ _)
549 = extractHsTyNames ty
551 getGates source_fvs (ClassDecl ctxt cls tvs _ sigs _ _ _ )
552 = (delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
554 `addOneToNameSet` cls)
555 `plusFV` maybe_double
557 get (ClassOpSig n _ ty _)
558 | n `elemNameSet` source_fvs = extractHsTyNames ty
559 | otherwise = emptyFVs
561 -- If we load any numeric class that doesn't have
562 -- Int as an instance, add Double to the gates.
563 -- This takes account of the fact that Double might be needed for
564 -- defaulting, but we don't want to load Double (and all its baggage)
565 -- if the more exotic classes aren't used at all.
566 maybe_double | nameUnique cls `elem` fractionalClassKeys
567 = unitFV (getName doubleTyCon)
571 getGates source_fvs (TySynonym tycon tvs ty _)
572 = delListFromNameSet (extractHsTyNames ty)
574 -- A type synonym type constructor isn't a "gate" for instance decls
576 getGates source_fvs (TyData _ ctxt tycon tvs cons _ _ _ _ _)
577 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
579 `addOneToNameSet` tycon
581 get (ConDecl n _ tvs ctxt details _)
582 | n `elemNameSet` source_fvs
583 -- If the constructor is method, get fvs from all its fields
584 = delListFromNameSet (get_details details `plusFV`
585 extractHsCtxtTyNames ctxt)
587 get (ConDecl n _ tvs ctxt (RecCon fields) _)
588 -- Even if the constructor isn't mentioned, the fields
589 -- might be, as selectors. They can't mention existentially
590 -- bound tyvars (typechecker checks for that) so no need for
591 -- the deleteListFromNameSet part
592 = foldr (plusFV . get_field) emptyFVs fields
594 get other_con = emptyFVs
596 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
597 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
598 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
600 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
601 | otherwise = emptyFVs
603 get_bang bty = extractHsTyNames (getBangType bty)
606 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
607 rather than a declaration.
610 getWiredInGates :: Name -> FreeVars
611 getWiredInGates name -- No classes are wired in
612 = case lookupNameEnv wiredInThingEnv name of
613 Just (AnId the_id) -> getWiredInGates_s (namesOfType (idType the_id))
617 -> getWiredInGates_s (delListFromNameSet (namesOfType ty) (map getName tyvars))
619 (tyvars,ty) = getSynTyConDefn tc
623 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
627 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
628 getInstDeclGates other = emptyFVs
632 %*********************************************************
634 \subsection{Getting in a declaration}
636 %*********************************************************
639 importDecl :: Name -> RnMG ImportDeclResult
641 data ImportDeclResult
645 | HereItIs (Module, RdrNameTyClDecl)
648 = -- Check if it was loaded before beginning this module
649 checkAlreadyAvailable name `thenRn` \ done ->
651 returnRn AlreadySlurped
654 -- Check if we slurped it in while compiling this module
655 getIfacesRn `thenRn` \ ifaces ->
656 if name `elemNameSet` iSlurp ifaces then
657 returnRn AlreadySlurped
660 -- Don't slurp in decls from this module's own interface file
661 -- (Indeed, this shouldn't happen.)
662 if isLocallyDefined name then
663 addWarnRn (importDeclWarn name) `thenRn_`
664 returnRn AlreadySlurped
667 -- When we find a wired-in name we must load its home
668 -- module so that we find any instance decls lurking therein
669 if name `elemNameEnv` wiredInThingEnv then
670 loadHomeInterface doc name `thenRn_`
673 else getNonWiredInDecl name
675 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
677 getNonWiredInDecl :: Name -> RnMG ImportDeclResult
678 getNonWiredInDecl needed_name
679 = traceRn doc_str `thenRn_`
680 loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
681 case lookupNameEnv (iDecls ifaces) needed_name of
683 {- OMIT DEFERRED STUFF FOR NOW, TILL GHCI WORKS
684 Just (version, avail, is_tycon_name, decl@(_, TyClD (TyData DataType _ _ _ _ ncons _ _ _ _)))
685 -- This case deals with deferred import of algebraic data types
687 | not opt_NoPruneTyDecls
689 && (opt_IgnoreIfacePragmas || ncons > 1)
690 -- We only defer if imported interface pragmas are ingored
691 -- or if it's not a product type.
692 -- Sole reason: The wrapper for a strict function may need to look
693 -- inside its arg, and hence need to see its arg type's constructors.
695 && not (getUnique tycon_name `elem` cCallishTyKeys)
696 -- Never defer ccall types; we have to unbox them,
697 -- and importing them does no harm
700 -> -- OK, so we're importing a deferrable data type
701 if needed_name == tycon_name
702 -- The needed_name is the TyCon of a data type decl
703 -- Record that it's slurped, put it in the deferred set
704 -- and don't return a declaration at all
705 setIfacesRn (recordSlurp (ifaces {iDeferred = iDeferred ifaces
706 `addOneToNameSet` tycon_name})
707 version (AvailTC needed_name [needed_name])) `thenRn_`
711 -- The needed name is a constructor of a data type decl,
712 -- getting a constructor, so remove the TyCon from the deferred set
713 -- (if it's there) and return the full declaration
714 setIfacesRn (recordSlurp (ifaces {iDeferred = iDeferred ifaces
715 `delFromNameSet` tycon_name})
716 version avail) `thenRn_`
717 returnRn (HereItIs decl)
719 tycon_name = availName avail
723 -> setIfacesRn (recordSlurp ifaces avail) `thenRn_`
724 returnRn (HereItIs decl)
727 -> addErrRn (getDeclErr needed_name) `thenRn_`
728 returnRn AlreadySlurped
730 doc_str = ptext SLIT("need decl for") <+> ppr needed_name
733 getDeferredDecls :: RnMG [(Module, RdrNameHsDecl)]
735 = getIfacesRn `thenRn` \ ifaces ->
737 decls_map = iDecls ifaces
738 deferred_names = nameSetToList (iDeferred ifaces)
739 get_abstract_decl n = case lookupNameEnv decls_map n of
740 Just (_, _, _, decl) -> decl
742 traceRn (sep [text "getDeferredDecls", nest 4 (fsep (map ppr deferred_names))]) `thenRn_`
743 returnRn (map get_abstract_decl deferred_names)
747 @getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
748 It behaves exactly as if the wired in decl were actually in an interface file.
751 \item if the wired-in name is a data type constructor or a data constructor,
752 it brings in the type constructor and all the data constructors; and
753 marks as ``occurrences'' any free vars of the data con.
755 \item similarly for synonum type constructor
757 \item if the wired-in name is another wired-in Id, it marks as ``occurrences''
758 the free vars of the Id's type.
760 \item it loads the interface file for the wired-in thing for the
761 sole purpose of making sure that its instance declarations are available
763 All this is necessary so that we know all types that are ``in play'', so
764 that we know just what instances to bring into scope.
767 %********************************************************
769 \subsection{Checking usage information}
771 %********************************************************
773 @recompileRequired@ is called from the HscMain. It checks whether
774 a recompilation is required. It needs access to the persistent state,
775 finder, etc, because it may have to load lots of interface files to
776 check their versions.
779 type RecompileRequired = Bool
780 upToDate = False -- Recompile not required
781 outOfDate = True -- Recompile required
783 recompileRequired :: Module
784 -> Bool -- Source unchanged
785 -> Maybe ModIface -- Old interface, if any
786 -> RnMG RecompileRequired
787 recompileRequired mod source_unchanged maybe_iface
788 = traceRn (text "Considering whether compilation is required for" <+> ppr mod <> colon) `thenRn_`
790 -- CHECK WHETHER THE SOURCE HAS CHANGED
791 if not source_unchanged then
792 traceRn (nest 4 (text "Source file changed or recompilation check turned off")) `thenRn_`
796 -- CHECK WHETHER WE HAVE AN OLD IFACE
798 Nothing -> traceRn (nest 4 (ptext SLIT("No old interface file"))) `thenRn_`
801 Just iface -> -- Source code unchanged and no errors yet... carry on
802 checkList [checkModUsage u | u <- mi_usages iface]
804 checkList :: [RnMG RecompileRequired] -> RnMG RecompileRequired
805 checkList [] = returnRn upToDate
806 checkList (check:checks) = check `thenRn` \ recompile ->
814 checkModUsage :: ImportVersion Name -> RnMG RecompileRequired
815 -- Given the usage information extracted from the old
816 -- M.hi file for the module being compiled, figure out
817 -- whether M needs to be recompiled.
819 checkModUsage (mod_name, _, _, NothingAtAll)
820 -- If CurrentModule.hi contains
822 -- then that simply records that Foo lies below CurrentModule in the
823 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
824 -- In this case we don't even want to open Foo's interface.
825 = up_to_date (ptext SLIT("Nothing used from:") <+> ppr mod_name)
827 checkModUsage (mod_name, _, _, whats_imported)
828 = tryLoadInterface doc_str mod_name ImportBySystem `thenRn` \ (ifaces, maybe_err) ->
830 Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"),
832 -- Couldn't find or parse a module mentioned in the
833 -- old interface file. Don't complain -- it might just be that
834 -- the current module doesn't need that import and it's been deleted
838 getHomeIfaceTableRn `thenRn` \ hit ->
840 mod_details = lookupTableByModName hit (iPIT ifaces) mod_name
841 `orElse` panic "checkModUsage"
842 new_vers = mi_version mod_details
843 new_decl_vers = vers_decls new_vers
845 case whats_imported of { -- NothingAtAll dealt with earlier
847 Everything old_mod_vers -> checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
849 out_of_date (ptext SLIT("...and I needed the whole module"))
853 Specifically old_mod_vers maybe_old_export_vers old_decl_vers old_rule_vers ->
856 checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
857 if not recompile then
862 if checkExportList maybe_old_export_vers new_vers then
863 out_of_date (ptext SLIT("Export list changed"))
867 if old_rule_vers /= vers_rules new_vers then
868 out_of_date (ptext SLIT("Rules changed"))
871 -- CHECK ITEMS ONE BY ONE
872 checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenRn` \ recompile ->
874 returnRn outOfDate -- This one failed, so just bail out now
876 up_to_date (ptext SLIT("...but the bits I use haven't."))
880 doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
882 ------------------------
883 checkModuleVersion old_mod_vers new_vers
884 | vers_module new_vers == old_mod_vers
885 = up_to_date (ptext SLIT("Module version unchanged"))
888 = out_of_date (ptext SLIT("Module version has changed"))
890 ------------------------
891 checkExportList Nothing new_vers = upToDate
892 checkExportList (Just v) new_vers = v /= vers_exports new_vers
894 ------------------------
895 checkEntityUsage new_vers (name,old_vers)
896 = case lookupNameEnv new_vers name of
898 Nothing -> -- We used it before, but it ain't there now
899 out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
901 Just new_vers -- It's there, but is it up to date?
902 | new_vers == old_vers -> returnRn upToDate
903 | otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
905 up_to_date msg = traceRn msg `thenRn_` returnRn upToDate
906 out_of_date msg = traceRn msg `thenRn_` returnRn outOfDate
910 %*********************************************************
914 %*********************************************************
918 = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
919 ptext SLIT("from module") <+> quotes (ppr (nameModule name))
924 "Compiler tried to import decl from interface file with same name as module."),
926 "(possible cause: module name clashes with interface file already in scope.)")
928 hsep [ptext SLIT("name:"), quotes (ppr name)]