2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnIfaces]{Cacheing and Renaming of Interfaces}
12 slurpImpDecls, closeDecls,
14 RecompileRequired, outOfDate, upToDate, recompileRequired
18 #include "HsVersions.h"
20 import CmdLineOpts ( opt_IgnoreIfacePragmas, opt_NoPruneDecls )
22 import HsSyn ( HsDecl(..), Sig(..), TyClDecl(..), ConDecl(..), ConDetails(..),
23 InstDecl(..), HsType(..), hsTyVarNames, getBangType
25 import HsImpExp ( ImportDecl(..) )
26 import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl )
27 import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl,
28 extractHsTyNames, extractHsCtxtTyNames,
29 tyClDeclFVs, ruleDeclFVs, instDeclFVs
31 import RnHiFiles ( tryLoadInterface, loadHomeInterface,
34 import RnSource ( rnTyClDecl, rnInstDecl, rnIfaceRuleDecl )
37 import Id ( idType, idName, globalIdDetails )
38 import IdInfo ( GlobalIdDetails(..) )
39 import Type ( namesOfType )
40 import FieldLabel ( fieldLabelTyCon )
41 import DataCon ( dataConTyCon )
42 import TyCon ( isSynTyCon, getSynTyConDefn, tyConClass_maybe, tyConName )
43 import Class ( className )
44 import Name ( Name {-instance NamedThing-}, nameOccName,
45 nameModule, isLocalName, NamedThing(..)
47 import NameEnv ( elemNameEnv, delFromNameEnv, lookupNameEnv )
49 import Module ( Module, ModuleEnv,
50 moduleName, isHomeModule,
51 ModuleName, WhereFrom(..),
53 extendModuleEnv_C, foldModuleEnv, lookupModuleEnv,
54 elemModuleSet, extendModuleSet
56 import PrelInfo ( wiredInThingEnv, hasKey, fractionalClassKey, numClassKey,
57 integerTyConName, doubleTyConName )
58 import Maybes ( maybeToBool )
62 import Util ( sortLt )
66 %*********************************************************
68 \subsection{Keeping track of what we've slurped, and version numbers}
70 %*********************************************************
72 mkImportInfo figures out what the ``usage information'' for this
73 moudule is; that is, what it must record in its interface file as the
76 We produce a line for every module B below the module, A, currently being
79 to record the fact that A does import B indirectly. This is used to decide
80 to look to look for B.hi rather than B.hi-boot when compiling a module that
81 imports A. This line says that A imports B, but uses nothing in it.
82 So we'll get an early bale-out when compiling A if B's version changes.
84 The usage information records:
87 \item (a) anything reachable from its body code
88 \item (b) any module exported with a @module Foo@
89 \item (c) anything reachable from an exported item
92 Why (b)? Because if @Foo@ changes then this module's export list
93 will change, so we must recompile this module at least as far as
94 making a new interface file --- but in practice that means complete
97 Why (c)? Consider this:
99 module A( f, g ) where | module B( f ) where
100 import B( f ) | f = h 3
104 Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
105 @A@'s usages? Our idea is that we aren't going to touch A.hi if it is
106 *identical* to what it was before. If anything about @B.f@ changes
107 than anyone who imports @A@ should be recompiled in case they use
108 @B.f@ (they'll get an early exit if they don't). So, if anything
109 about @B.f@ changes we'd better make sure that something in A.hi
110 changes, and the convenient way to do that is to record the version
111 number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
112 complete recompiation of A, which is overkill but it's the only way to
113 write a new, slightly different, A.hi.
115 But the example is tricker. Even if @B.f@ doesn't change at all,
116 @B.h@ may do so, and this change may not be reflected in @f@'s version
117 number. But with -O, a module that imports A must be recompiled if
118 @B.h@ changes! So A must record a dependency on @B.h@. So we treat
119 the occurrence of @B.f@ in the export list *just as if* it were in the
120 code of A, and thereby haul in all the stuff reachable from it.
122 *** Conclusion: if A mentions B.f in its export list,
123 behave just as if A mentioned B.f in its source code,
124 and slurp in B.f and all its transitive closure ***
126 [NB: If B was compiled with -O, but A isn't, we should really *still*
127 haul in all the unfoldings for B, in case the module that imports A *is*
128 compiled with -O. I think this is the case.]
131 mkImportInfo :: ModuleName -- Name of this module
132 -> [ImportDecl n] -- The import decls
133 -> RnMG [ImportVersion Name]
135 mkImportInfo this_mod imports
136 = getIfacesRn `thenRn` \ ifaces ->
137 getHomeIfaceTableRn `thenRn` \ hit ->
139 (imp_pkg_mods, imp_home_names) = iVSlurp ifaces
142 import_all_mods :: [ModuleName]
143 -- Modules where we imported all the names
144 -- (apart from hiding some, perhaps)
145 import_all_mods = [ m | ImportDecl m _ _ _ imp_list _ <- imports,
146 import_all imp_list ]
148 import_all (Just (False, _)) = False -- Imports are specified explicitly
149 import_all other = True -- Everything is imported
151 -- mv_map groups together all the things imported and used
152 -- from a particular module in this package
153 -- We use a finite map because we want the domain
154 mv_map :: ModuleEnv [Name]
155 mv_map = foldNameSet add_mv emptyModuleEnv imp_home_names
156 add_mv name mv_map = extendModuleEnv_C add_item mv_map mod [name]
158 mod = nameModule name
159 add_item names _ = name:names
161 -- In our usage list we record
162 -- a) Specifically: Detailed version info for imports from modules in this package
163 -- Gotten from iVSlurp plus import_all_mods
165 -- b) Everything: Just the module version for imports from modules in other packages
166 -- Gotten from iVSlurp plus import_all_mods
168 -- c) NothingAtAll: The name only of modules, Baz, in this package that are 'below' us,
169 -- but which we didn't need at all (this is needed only to decide whether
170 -- to open Baz.hi or Baz.hi-boot higher up the tree).
171 -- This happens when a module, Foo, that we explicitly imported has
172 -- 'import Baz' in its interface file, recording that Baz is below
173 -- Foo in the module dependency hierarchy. We want to propagate this info.
174 -- These modules are in a combination of HIT/PIT and iImpModInfo
176 -- d) NothingAtAll: The name only of all orphan modules we know of (this is needed
177 -- so that anyone who imports us can find the orphan modules)
178 -- These modules are in a combination of HIT/PIT and iImpModInfo
180 import_info0 = foldModuleEnv mk_imp_info [] pit
181 import_info1 = foldModuleEnv mk_imp_info import_info0 hit
182 import_info = not_even_opened_imports ++ import_info1
184 -- Recall that iImpModInfo describes modules that have been mentioned
185 -- in the import lists of interfaces we have opened, but which we have
186 -- not even opened when compiling this module
187 not_even_opened_imports = [ (mod_name, orphans, is_boot, NothingAtAll)
188 | (mod_name, (orphans, is_boot)) <- fmToList (iImpModInfo ifaces) ]
191 mk_imp_info :: ModIface -> [ImportVersion Name] -> [ImportVersion Name]
192 mk_imp_info iface so_far
194 | Just ns <- lookupModuleEnv mv_map mod -- Case (a)
195 = go_for_it (Specifically mod_vers maybe_export_vers
196 (mk_import_items ns) rules_vers)
198 | mod `elemModuleSet` imp_pkg_mods -- Case (b)
199 = go_for_it (Everything mod_vers)
201 | import_all_mod -- Case (a) and (b); the import-all part
202 = if is_home_pkg_mod then
203 go_for_it (Specifically mod_vers (Just export_vers) [] rules_vers)
204 -- Since the module isn't in the mv_map, presumably we
205 -- didn't actually import anything at all from it
207 go_for_it (Everything mod_vers)
209 | is_home_pkg_mod || has_orphans -- Case (c) or (d)
210 = go_for_it NothingAtAll
214 go_for_it exports = (mod_name, has_orphans, mi_boot iface, exports) : so_far
216 mod = mi_module iface
217 mod_name = moduleName mod
218 is_home_pkg_mod = isHomeModule mod
219 version_info = mi_version iface
220 version_env = vers_decls version_info
221 mod_vers = vers_module version_info
222 rules_vers = vers_rules version_info
223 export_vers = vers_exports version_info
224 import_all_mod = mod_name `elem` import_all_mods
225 has_orphans = mi_orphan iface
227 -- The sort is to put them into canonical order
228 mk_import_items ns = [(n,v) | n <- sortLt lt_occ ns,
229 let v = lookupVersion version_env n
232 lt_occ n1 n2 = nameOccName n1 < nameOccName n2
234 maybe_export_vers | import_all_mod = Just (vers_exports version_info)
235 | otherwise = Nothing
240 %*********************************************************
242 \subsection{Slurping declarations}
244 %*********************************************************
247 -------------------------------------------------------
248 slurpImpDecls source_fvs
249 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
251 -- The current slurped-set records all local things
252 slurpSourceRefs source_fvs `thenRn` \ (decls, needed) ->
254 -- Then get everything else
255 closeDecls decls needed
258 -------------------------------------------------------
259 slurpSourceRefs :: FreeVars -- Variables referenced in source
260 -> RnMG ([RenamedHsDecl],
261 FreeVars) -- Un-satisfied needs
262 -- The declaration (and hence home module) of each gate has
263 -- already been loaded
265 slurpSourceRefs source_fvs
266 = go_outer [] -- Accumulating decls
267 emptyFVs -- Unsatisfied needs
268 emptyFVs -- Accumulating gates
269 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
271 -- The outer loop repeatedly slurps the decls for the current gates
272 -- and the instance decls
274 -- The outer loop is needed because consider
275 -- instance Foo a => Baz (Maybe a) where ...
276 -- It may be that Baz and Maybe are used in the source module,
277 -- but not Foo; so we need to chase Foo too.
279 -- We also need to follow superclass refs. In particular, 'chasing Foo' must
280 -- include actually getting in Foo's class decl
281 -- class Wib a => Foo a where ..
282 -- so that its superclasses are discovered. The point is that Wib is a gate too.
283 -- We do this for tycons too, so that we look through type synonyms.
285 go_outer decls fvs all_gates []
286 = returnRn (decls, fvs)
288 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
289 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
290 foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
291 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
292 rnIfaceInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
293 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
294 (nameSetToList (gates2 `minusNameSet` all_gates))
295 -- Knock out the all_gates because even if we don't slurp any new
296 -- decls we can get some apparently-new gates from wired-in names
297 -- and we get an infinite loop
299 go_inner (decls, fvs, gates) wanted_name
300 = importDecl wanted_name `thenRn` \ import_result ->
301 case import_result of
302 AlreadySlurped -> returnRn (decls, fvs, gates)
303 InTypeEnv ty_thing -> returnRn (decls, fvs, gates `plusFV` getWiredInGates ty_thing)
305 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
306 returnRn (TyClD new_decl : decls,
308 gates `plusFV` getGates source_fvs new_decl)
313 -------------------------------------------------------
314 -- closeDecls keeps going until the free-var set is empty
315 closeDecls decls needed
316 | not (isEmptyFVs needed)
317 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
318 closeDecls decls1 needed1
321 = getImportedRules `thenRn` \ rule_decls ->
323 [] -> returnRn decls -- No new rules, so we are done
324 other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' ->
326 rule_fvs = plusFVs (map ruleDeclFVs rule_decls')
328 traceRn (text "closeRules" <+> ppr rule_decls' $$ fsep (map ppr (nameSetToList rule_fvs))) `thenRn_`
329 closeDecls (map RuleD rule_decls' ++ decls) rule_fvs
333 -------------------------------------------------------
334 -- Augment decls with any decls needed by needed.
335 -- Return also free vars of the new decls (only)
336 slurpDecls decls needed
337 = go decls emptyFVs (nameSetToList needed)
339 go decls fvs [] = returnRn (decls, fvs)
340 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
343 -------------------------------------------------------
344 slurpDecl decls fvs wanted_name
345 = importDecl wanted_name `thenRn` \ import_result ->
346 case import_result of
347 -- Found a declaration... rename it
348 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
349 returnRn (TyClD new_decl:decls, fvs1 `plusFV` fvs)
351 -- No declaration... (wired in thing, or deferred, or already slurped)
352 other -> returnRn (decls, fvs)
355 -------------------------------------------------------
356 rnIfaceDecls rn decls = mapRn (rnIfaceDecl rn) decls
357 rnIfaceDecl rn (mod, decl) = initIfaceRnMS mod (rn decl)
359 rnIfaceInstDecls decls fvs gates inst_decls
360 = rnIfaceDecls rnInstDecl inst_decls `thenRn` \ inst_decls' ->
361 returnRn (map InstD inst_decls' ++ decls,
362 fvs `plusFV` plusFVs (map instDeclFVs inst_decls'),
363 gates `plusFV` plusFVs (map getInstDeclGates inst_decls'))
365 rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl) `thenRn` \ decl' ->
366 returnRn (decl', tyClDeclFVs decl')
371 recordDeclSlurp ifaces@(Ifaces { iDecls = (decls_map, n_slurped),
372 iSlurp = slurped_names,
375 = ASSERT2( not (isLocalName (availName avail)), ppr avail )
376 ifaces { iDecls = (new_decls_map, n_slurped+1),
377 iSlurp = new_slurped_names,
378 iVSlurp = updateVSlurp vslurp (availName avail) }
380 new_decls_map = foldl delFromNameEnv decls_map (availNames avail)
381 new_slurped_names = addAvailToNameSet slurped_names avail
384 -- recordTypeEnvSlurp is used when we slurp something that's
385 -- already in the type environment, that was not slurped in an earlier compilation.
386 -- We record it in the iVSlurp set, because that's used to
387 -- generate usage information
389 recordTypeEnvSlurp ifaces ty_thing
390 = ifaces { iVSlurp = updateVSlurp (iVSlurp ifaces) (get_main_name ty_thing) }
392 -- Tiresomely, we must get the "main" name for the
393 -- thing, because that's what VSlurp contains, and what
394 -- is recorded in the usage information
395 get_main_name (AClass cl) = className cl
396 get_main_name (ATyCon tc)
397 | Just clas <- tyConClass_maybe tc = get_main_name (AClass clas)
398 | otherwise = tyConName tc
399 get_main_name (AnId id)
400 = case globalIdDetails id of
401 DataConId dc -> get_main_name (ATyCon (dataConTyCon dc))
402 DataConWrapId dc -> get_main_name (ATyCon (dataConTyCon dc))
403 RecordSelId lbl -> get_main_name (ATyCon (fieldLabelTyCon lbl))
406 updateVSlurp (imp_mods, imp_names) main_name
407 | isHomeModule mod = (imp_mods, addOneToNameSet imp_names main_name)
408 | otherwise = (extendModuleSet imp_mods mod, imp_names)
410 mod = nameModule main_name
412 recordLocalSlurps new_names
413 = getIfacesRn `thenRn` \ ifaces ->
414 setIfacesRn (ifaces { iSlurp = iSlurp ifaces `unionNameSets` new_names })
419 %*********************************************************
421 \subsection{Extracting the `gates'}
423 %*********************************************************
427 We want to avoid sucking in too many instance declarations.
428 An instance decl is only useful if the types and classes mentioned in
429 its 'head' are all available in the program being compiled. E.g.
431 instance (..) => C (T1 a) (T2 b) where ...
433 is only useful if C, T1 and T2 are all "available". So we keep
434 instance decls that have been parsed from .hi files, but not yet
435 slurped in, in a pool called the 'gated instance pool'.
436 Each has its set of 'gates': {C, T1, T2} in the above example.
438 More precisely, the gates of a module are the types and classes
439 that are mentioned in:
442 b) the type of an Id that's mentioned in the source code
443 [includes constructors and selectors]
444 c) the RHS of a type synonym that is a gate
445 d) the superclasses of a class that is a gate
446 e) the context of an instance decl that is slurped in
448 We slurp in an instance decl from the gated instance pool iff
450 all its gates are either in the gates of the module,
451 or are a previously-loaded class.
453 The latter constraint is because there might have been an instance
454 decl slurped in during an earlier compilation, like this:
456 instance Foo a => Baz (Maybe a) where ...
458 In the module being compiled we might need (Baz (Maybe T)), where T
459 is defined in this module, and hence we need (Foo T). So @Foo@ becomes
460 a gate. But there's no way to 'see' that, so we simply treat all
461 previously-loaded classes as gates.
463 Consructors and class operations
464 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
465 When we import a declaration like
467 data T = T1 Wibble | T2 Wobble
469 we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless}
470 @T1@, @T2@ respectively are mentioned by the user program. If only
471 @T@ is mentioned we want only @T@ to be a gate; that way we don't suck
472 in useless instance decls for (say) @Eq Wibble@, when they can't
475 And that's just what (b) says: we only treat T1's type as a gate if
476 T1 is mentioned. getGates, which deals with decls we are slurping in,
477 has to be a bit careful, because a mention of T1 will slurp in T's whole
480 -----------------------------
481 @getGates@ takes a newly imported (and renamed) decl, and the free
482 vars of the source program, and extracts from the decl the gate names.
485 getGates :: FreeVars -- Things mentioned in the source program
489 getGates source_fvs decl
490 = get_gates (\n -> n `elemNameSet` source_fvs) decl
492 get_gates is_used (IfaceSig {tcdType = ty}) = extractHsTyNames ty
494 get_gates is_used (ClassDecl { tcdCtxt = ctxt, tcdName = cls, tcdTyVars = tvs, tcdSigs = sigs})
495 = (super_cls_and_sigs `addOneToNameSet` cls) `unionNameSets`
496 implicitClassGates cls
498 super_cls_and_sigs = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
500 get (ClassOpSig n _ ty _)
501 | is_used n = extractHsTyNames ty
502 | otherwise = emptyFVs
504 get_gates is_used (TySynonym {tcdTyVars = tvs, tcdSynRhs = ty})
505 = delListFromNameSet (extractHsTyNames ty) (hsTyVarNames tvs)
506 -- A type synonym type constructor isn't a "gate" for instance decls
508 get_gates is_used (TyData {tcdCtxt = ctxt, tcdName = tycon, tcdTyVars = tvs, tcdCons = cons})
509 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
511 `addOneToNameSet` tycon
513 get (ConDecl n _ tvs ctxt details _)
515 -- If the constructor is method, get fvs from all its fields
516 = delListFromNameSet (get_details details `plusFV`
517 extractHsCtxtTyNames ctxt)
519 get (ConDecl n _ tvs ctxt (RecCon fields) _)
520 -- Even if the constructor isn't mentioned, the fields
521 -- might be, as selectors. They can't mention existentially
522 -- bound tyvars (typechecker checks for that) so no need for
523 -- the deleteListFromNameSet part
524 = foldr (plusFV . get_field) emptyFVs fields
526 get other_con = emptyFVs
528 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
529 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
530 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
532 get_field (fs,t) | any is_used fs = get_bang t
533 | otherwise = emptyFVs
535 get_bang bty = extractHsTyNames (getBangType bty)
537 implicitClassGates :: Name -> FreeVars
538 implicitClassGates cls
539 -- If we load class Num, add Integer to the free gates
540 -- This takes account of the fact that Integer might be needed for
541 -- defaulting, but we don't want to load Integer (and all its baggage)
542 -- if there's no numeric stuff needed.
543 -- Similarly for class Fractional and Double
545 -- NB: adding T to the gates will force T to be loaded
547 -- NB: If we load (say) Floating, we'll end up loading Fractional too,
548 -- since Fractional is a superclass of Floating
549 | cls `hasKey` numClassKey = unitFV integerTyConName
550 | cls `hasKey` fractionalClassKey = unitFV doubleTyConName
551 | otherwise = emptyFVs
554 @getWiredInGates@ is just like @getGates@, but it sees a previously-loaded
555 thing rather than a declaration.
558 getWiredInGates :: TyThing -> FreeVars
559 -- The TyThing is one that we already have in our type environment, either
560 -- a) because the TyCon or Id is wired in, or
561 -- b) from a previous compile
562 -- Either way, we might have instance decls in the (persistent) collection
563 -- of parsed-but-not-slurped instance decls that should be slurped in.
564 -- This might be the first module that mentions both the type and the class
565 -- for that instance decl, even though both the type and the class were
566 -- mentioned in other modules, and hence are in the type environment
568 getWiredInGates (AnId the_id) = namesOfType (idType the_id)
569 getWiredInGates (AClass cl) = implicitClassGates (getName cl)
570 -- The superclasses must also be previously
571 -- loaded, and hence are automatically gates
572 -- All previously-loaded classes are automatically gates
573 -- See "The gating story" above
574 getWiredInGates (ATyCon tc)
575 | isSynTyCon tc = delListFromNameSet (namesOfType ty) (map getName tyvars)
576 | otherwise = unitFV (getName tc)
578 (tyvars,ty) = getSynTyConDefn tc
580 getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty
584 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameInstDecl)]
585 getImportedInstDecls gates
586 = -- First, load any orphan-instance modules that aren't aready loaded
587 -- Orphan-instance modules are recorded in the module dependecnies
588 getIfacesRn `thenRn` \ ifaces ->
591 [mod | (mod, (True, _)) <- fmToList (iImpModInfo ifaces)]
593 loadOrphanModules orphan_mods `thenRn_`
595 -- Now we're ready to grab the instance declarations
596 -- Find the un-gated ones and return them,
597 -- removing them from the bag kept in Ifaces
598 getIfacesRn `thenRn` \ ifaces ->
599 getTypeEnvRn `thenRn` \ lookup ->
602 | n `elemNameSet` gates = True
603 | otherwise = case lookup n of { Just (AClass c) -> True; other -> False }
604 -- See "The gating story" above for the AClass thing
606 (decls, new_insts) = selectGated available (iInsts ifaces)
608 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
610 traceRn (sep [text "getImportedInstDecls:",
611 nest 4 (fsep (map ppr gate_list)),
612 text "Slurped" <+> int (length decls) <+> text "instance declarations",
613 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
616 gate_list = nameSetToList gates
618 ppr_brief_inst_decl (mod, InstDecl inst_ty _ _ _ _)
620 HsForAllTy _ _ tau -> ppr tau
623 getImportedRules :: RnMG [(Module,RdrNameRuleDecl)]
625 | opt_IgnoreIfacePragmas = returnRn []
627 = getIfacesRn `thenRn` \ ifaces ->
628 getTypeEnvRn `thenRn` \ lookup ->
630 -- Slurp rules for anything that is slurped,
631 -- either now or previously
632 gates = iSlurp ifaces
633 available n = n `elemNameSet` gates || maybeToBool (lookup n)
634 (decls, new_rules) = selectGated available (iRules ifaces)
639 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
640 traceRn (sep [text "getImportedRules:",
641 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
644 selectGated :: (Name->Bool) -> GatedDecls d
645 -> ([(Module,d)], GatedDecls d)
646 selectGated available (decl_bag, n_slurped)
647 -- Select only those decls whose gates are *all* available
649 | opt_NoPruneDecls -- Just to try the effect of not gating at all
651 decls = foldrBag (\ (_,d) ds -> d:ds) [] decl_bag -- Grab them all
653 (decls, (emptyBag, n_slurped + length decls))
657 = case foldrBag select ([], emptyBag) decl_bag of
658 (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls))
660 select (reqd, decl) (yes, no)
661 | all available reqd = (decl:yes, no)
662 | otherwise = (yes, (reqd,decl) `consBag` no)
666 %*********************************************************
668 \subsection{Getting in a declaration}
670 %*********************************************************
673 importDecl :: Name -> RnMG ImportDeclResult
675 data ImportDeclResult
678 | HereItIs (Module, RdrNameTyClDecl)
681 = -- STEP 1: Check if we've slurped it in while compiling this module
682 getIfacesRn `thenRn` \ ifaces ->
683 if name `elemNameSet` iSlurp ifaces then
684 returnRn AlreadySlurped
688 -- STEP 2: Check if it's already in the type environment
689 getTypeEnvRn `thenRn` \ lookup ->
690 case lookup name of {
692 | name `elemNameEnv` wiredInThingEnv
693 -> -- When we find a wired-in name we must load its home
694 -- module so that we find any instance decls lurking therein
695 loadHomeInterface wi_doc name `thenRn_`
696 returnRn (InTypeEnv ty_thing)
699 -> -- Very important: record that we've seen it
700 -- See comments with recordTypeEnvSlurp
701 setIfacesRn (recordTypeEnvSlurp ifaces ty_thing) `thenRn_`
702 returnRn (InTypeEnv ty_thing) ;
706 -- STEP 3: OK, we have to slurp it in from an interface file
707 -- First load the interface file
708 traceRn nd_doc `thenRn_`
709 loadHomeInterface nd_doc name `thenRn_`
710 getIfacesRn `thenRn` \ ifaces ->
712 -- STEP 4: Get the declaration out
714 (decls_map, _) = iDecls ifaces
716 case lookupNameEnv decls_map name of
717 Just (avail,_,decl) -> setIfacesRn (recordDeclSlurp ifaces avail) `thenRn_`
718 returnRn (HereItIs decl)
720 Nothing -> addErrRn (getDeclErr name) `thenRn_`
721 returnRn AlreadySlurped
724 wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name
725 nd_doc = ptext SLIT("need decl for") <+> ppr name
730 %********************************************************
732 \subsection{Checking usage information}
734 %********************************************************
736 @recompileRequired@ is called from the HscMain. It checks whether
737 a recompilation is required. It needs access to the persistent state,
738 finder, etc, because it may have to load lots of interface files to
739 check their versions.
742 type RecompileRequired = Bool
743 upToDate = False -- Recompile not required
744 outOfDate = True -- Recompile required
746 recompileRequired :: FilePath -- Only needed for debug msgs
747 -> ModIface -- Old interface
748 -> RnMG RecompileRequired
749 recompileRequired iface_path iface
750 = traceHiDiffsRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_`
752 -- Source code unchanged and no errors yet... carry on
753 checkList [checkModUsage u | u <- mi_usages iface]
755 checkList :: [RnMG RecompileRequired] -> RnMG RecompileRequired
756 checkList [] = returnRn upToDate
757 checkList (check:checks) = check `thenRn` \ recompile ->
765 checkModUsage :: ImportVersion Name -> RnMG RecompileRequired
766 -- Given the usage information extracted from the old
767 -- M.hi file for the module being compiled, figure out
768 -- whether M needs to be recompiled.
770 checkModUsage (mod_name, _, _, NothingAtAll)
771 -- If CurrentModule.hi contains
773 -- then that simply records that Foo lies below CurrentModule in the
774 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
775 -- In this case we don't even want to open Foo's interface.
776 = up_to_date (ptext SLIT("Nothing used from:") <+> ppr mod_name)
778 checkModUsage (mod_name, _, is_boot, whats_imported)
779 = -- Load the imported interface is possible
780 -- We use tryLoadInterface, because failure is not an error
781 -- (might just be that the old .hi file for this module is out of date)
782 -- We use ImportByUser/ImportByUserSource as the 'from' flag,
783 -- a) because we need to know whether to load the .hi-boot file
784 -- b) because loadInterface things matters are amiss if we
785 -- ImportBySystem an interface it knows nothing about
787 doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
788 from | is_boot = ImportByUserSource
789 | otherwise = ImportByUser
791 traceHiDiffsRn (text "Checking usages for module" <+> ppr mod_name) `thenRn_`
792 tryLoadInterface doc_str mod_name from `thenRn` \ (iface, maybe_err) ->
795 Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"),
797 -- Couldn't find or parse a module mentioned in the
798 -- old interface file. Don't complain -- it might just be that
799 -- the current module doesn't need that import and it's been deleted
803 new_vers = mi_version iface
804 new_decl_vers = vers_decls new_vers
806 case whats_imported of { -- NothingAtAll dealt with earlier
808 Everything old_mod_vers -> checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
810 out_of_date (ptext SLIT("...and I needed the whole module"))
814 Specifically old_mod_vers maybe_old_export_vers old_decl_vers old_rule_vers ->
817 checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
818 if not recompile then
823 if checkExportList maybe_old_export_vers new_vers then
824 out_of_date (ptext SLIT("Export list changed"))
828 if old_rule_vers /= vers_rules new_vers then
829 out_of_date (ptext SLIT("Rules changed"))
832 -- CHECK ITEMS ONE BY ONE
833 checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenRn` \ recompile ->
835 returnRn outOfDate -- This one failed, so just bail out now
837 up_to_date (ptext SLIT("...but the bits I use haven't."))
841 ------------------------
842 checkModuleVersion old_mod_vers new_vers
843 | vers_module new_vers == old_mod_vers
844 = up_to_date (ptext SLIT("Module version unchanged"))
847 = out_of_date (ptext SLIT("Module version has changed"))
849 ------------------------
850 checkExportList Nothing new_vers = upToDate
851 checkExportList (Just v) new_vers = v /= vers_exports new_vers
853 ------------------------
854 checkEntityUsage new_vers (name,old_vers)
855 = case lookupNameEnv new_vers name of
857 Nothing -> -- We used it before, but it ain't there now
858 out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
860 Just new_vers -- It's there, but is it up to date?
861 | new_vers == old_vers -> traceHiDiffsRn (text "Up to date" <+> ppr name <+> parens (ppr new_vers)) `thenRn_` returnRn upToDate
862 | otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
864 up_to_date msg = traceHiDiffsRn msg `thenRn_` returnRn upToDate
865 out_of_date msg = traceHiDiffsRn msg `thenRn_` returnRn outOfDate
869 %*********************************************************
873 %*********************************************************
877 = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
878 ptext SLIT("from module") <+> quotes (ppr (nameModule name))