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 TcType ( 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 spec'd 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
163 -- a) Specifically: Detailed version info for imports
164 -- from modules in this package Gotten from iVSlurp plus
167 -- b) Everything: Just the module version for imports
168 -- from modules in other packages Gotten from iVSlurp plus
171 -- c) NothingAtAll: The name only of modules, Baz, in
172 -- this package that are 'below' us, but which we didn't need
173 -- at all (this is needed only to decide whether to open Baz.hi
174 -- or Baz.hi-boot higher up the tree). This happens when a
175 -- module, Foo, that we explicitly imported has 'import Baz' in
176 -- its interface file, recording that Baz is below Foo in the
177 -- module dependency hierarchy. We want to propagate this
178 -- info. These modules are in a combination of HIT/PIT and
181 -- d) NothingAtAll: The name only of all orphan modules
182 -- we know of (this is needed so that anyone who imports us can
183 -- find the orphan modules) These modules are in a combination
184 -- of HIT/PIT and iImpModInfo
186 import_info0 = foldModuleEnv mk_imp_info [] pit
187 import_info1 = foldModuleEnv mk_imp_info import_info0 hit
188 import_info = not_even_opened_imports ++ import_info1
190 -- Recall that iImpModInfo describes modules that have
191 -- been mentioned in the import lists of interfaces we
192 -- have opened, but which we have not even opened when
193 -- compiling this module
194 not_even_opened_imports =
195 [ (mod_name, orphans, is_boot, NothingAtAll)
196 | (mod_name, (orphans, is_boot)) <- fmToList (iImpModInfo ifaces) ]
199 mk_imp_info :: ModIface -> [ImportVersion Name] -> [ImportVersion Name]
200 mk_imp_info iface so_far
202 | Just ns <- lookupModuleEnv mv_map mod -- Case (a)
203 = go_for_it (Specifically mod_vers maybe_export_vers
204 (mk_import_items ns) rules_vers)
206 | mod `elemModuleSet` imp_pkg_mods -- Case (b)
207 = go_for_it (Everything mod_vers)
209 | import_all_mod -- Case (a) and (b); the import-all part
210 = if is_home_pkg_mod then
211 go_for_it (Specifically mod_vers (Just export_vers) [] rules_vers)
212 -- Since the module isn't in the mv_map, presumably we
213 -- didn't actually import anything at all from it
215 go_for_it (Everything mod_vers)
217 | is_home_pkg_mod || has_orphans -- Case (c) or (d)
218 = go_for_it NothingAtAll
222 go_for_it exports = (mod_name, has_orphans, mi_boot iface, exports) : so_far
224 mod = mi_module iface
225 mod_name = moduleName mod
226 is_home_pkg_mod = isHomeModule mod
227 version_info = mi_version iface
228 version_env = vers_decls version_info
229 mod_vers = vers_module version_info
230 rules_vers = vers_rules version_info
231 export_vers = vers_exports version_info
232 import_all_mod = mod_name `elem` import_all_mods
233 has_orphans = mi_orphan iface
235 -- The sort is to put them into canonical order
236 mk_import_items ns = [(n,v) | n <- sortLt lt_occ ns,
237 let v = lookupVersion version_env n
240 lt_occ n1 n2 = nameOccName n1 < nameOccName n2
242 maybe_export_vers | import_all_mod = Just (vers_exports version_info)
243 | otherwise = Nothing
248 %*********************************************************
250 \subsection{Slurping declarations}
252 %*********************************************************
255 -------------------------------------------------------
256 slurpImpDecls source_fvs
257 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
259 -- The current slurped-set records all local things
260 slurpSourceRefs source_fvs `thenRn` \ (decls, needed) ->
262 -- Then get everything else
263 closeDecls decls needed
266 -------------------------------------------------------
267 slurpSourceRefs :: FreeVars -- Variables referenced in source
268 -> RnMG ([RenamedHsDecl],
269 FreeVars) -- Un-satisfied needs
270 -- The declaration (and hence home module) of each gate has
271 -- already been loaded
273 slurpSourceRefs source_fvs
274 = go_outer [] -- Accumulating decls
275 emptyFVs -- Unsatisfied needs
276 emptyFVs -- Accumulating gates
277 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
279 -- The outer loop repeatedly slurps the decls for the current gates
280 -- and the instance decls
282 -- The outer loop is needed because consider
283 -- instance Foo a => Baz (Maybe a) where ...
284 -- It may be that Baz and Maybe are used in the source module,
285 -- but not Foo; so we need to chase Foo too.
287 -- We also need to follow superclass refs. In particular, 'chasing Foo' must
288 -- include actually getting in Foo's class decl
289 -- class Wib a => Foo a where ..
290 -- so that its superclasses are discovered. The point is that Wib is a gate too.
291 -- We do this for tycons too, so that we look through type synonyms.
293 go_outer decls fvs all_gates []
294 = returnRn (decls, fvs)
296 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
297 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
298 foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
299 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
300 rnIfaceInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
301 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
302 (nameSetToList (gates2 `minusNameSet` all_gates))
303 -- Knock out the all_gates because even if we don't slurp any new
304 -- decls we can get some apparently-new gates from wired-in names
305 -- and we get an infinite loop
307 go_inner (decls, fvs, gates) wanted_name
308 = importDecl wanted_name `thenRn` \ import_result ->
309 case import_result of
310 AlreadySlurped -> returnRn (decls, fvs, gates)
311 InTypeEnv ty_thing -> returnRn (decls, fvs, gates `plusFV` getWiredInGates ty_thing)
313 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
314 returnRn (TyClD new_decl : decls,
316 gates `plusFV` getGates source_fvs new_decl)
321 -------------------------------------------------------
322 -- closeDecls keeps going until the free-var set is empty
323 closeDecls decls needed
324 | not (isEmptyFVs needed)
325 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
326 closeDecls decls1 needed1
329 = getImportedRules `thenRn` \ rule_decls ->
331 [] -> returnRn decls -- No new rules, so we are done
332 other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' ->
334 rule_fvs = plusFVs (map ruleDeclFVs rule_decls')
336 traceRn (text "closeRules" <+> ppr rule_decls' $$ fsep (map ppr (nameSetToList rule_fvs))) `thenRn_`
337 closeDecls (map RuleD rule_decls' ++ decls) rule_fvs
341 -------------------------------------------------------
342 -- Augment decls with any decls needed by needed.
343 -- Return also free vars of the new decls (only)
344 slurpDecls decls needed
345 = go decls emptyFVs (nameSetToList needed)
347 go decls fvs [] = returnRn (decls, fvs)
348 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
351 -------------------------------------------------------
352 slurpDecl decls fvs wanted_name
353 = importDecl wanted_name `thenRn` \ import_result ->
354 case import_result of
355 -- Found a declaration... rename it
356 HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
357 returnRn (TyClD new_decl:decls, fvs1 `plusFV` fvs)
359 -- No declaration... (wired in thing, or deferred, or already slurped)
360 other -> returnRn (decls, fvs)
363 -------------------------------------------------------
364 rnIfaceDecls rn decls = mapRn (rnIfaceDecl rn) decls
365 rnIfaceDecl rn (mod, decl) = initIfaceRnMS mod (rn decl)
367 rnIfaceInstDecls decls fvs gates inst_decls
368 = rnIfaceDecls rnInstDecl inst_decls `thenRn` \ inst_decls' ->
369 returnRn (map InstD inst_decls' ++ decls,
370 fvs `plusFV` plusFVs (map instDeclFVs inst_decls'),
371 gates `plusFV` plusFVs (map getInstDeclGates inst_decls'))
373 rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl) `thenRn` \ decl' ->
374 returnRn (decl', tyClDeclFVs decl')
379 recordDeclSlurp ifaces@(Ifaces { iDecls = (decls_map, n_slurped),
380 iSlurp = slurped_names,
383 = ASSERT2( not (isLocalName (availName avail)), ppr avail )
384 ifaces { iDecls = (new_decls_map, n_slurped+1),
385 iSlurp = new_slurped_names,
386 iVSlurp = updateVSlurp vslurp (availName avail) }
388 new_decls_map = foldl delFromNameEnv decls_map (availNames avail)
389 new_slurped_names = addAvailToNameSet slurped_names avail
392 -- recordTypeEnvSlurp is used when we slurp something that's
393 -- already in the type environment, that was not slurped in an earlier compilation.
394 -- We record it in the iVSlurp set, because that's used to
395 -- generate usage information
397 recordTypeEnvSlurp ifaces ty_thing
398 = ifaces { iVSlurp = updateVSlurp (iVSlurp ifaces) (get_main_name ty_thing) }
400 -- Tiresomely, we must get the "main" name for the
401 -- thing, because that's what VSlurp contains, and what
402 -- is recorded in the usage information
403 get_main_name (AClass cl) = className cl
404 get_main_name (ATyCon tc)
405 | Just clas <- tyConClass_maybe tc = get_main_name (AClass clas)
406 | otherwise = tyConName tc
407 get_main_name (AnId id)
408 = case globalIdDetails id of
409 DataConId dc -> get_main_name (ATyCon (dataConTyCon dc))
410 DataConWrapId dc -> get_main_name (ATyCon (dataConTyCon dc))
411 RecordSelId lbl -> get_main_name (ATyCon (fieldLabelTyCon lbl))
414 updateVSlurp (imp_mods, imp_names) main_name
415 | isHomeModule mod = (imp_mods, addOneToNameSet imp_names main_name)
416 | otherwise = (extendModuleSet imp_mods mod, imp_names)
418 mod = nameModule main_name
420 recordLocalSlurps new_names
421 = getIfacesRn `thenRn` \ ifaces ->
422 setIfacesRn (ifaces { iSlurp = iSlurp ifaces `unionNameSets` new_names })
427 %*********************************************************
429 \subsection{Extracting the `gates'}
431 %*********************************************************
435 We want to avoid sucking in too many instance declarations.
436 An instance decl is only useful if the types and classes mentioned in
437 its 'head' are all available in the program being compiled. E.g.
439 instance (..) => C (T1 a) (T2 b) where ...
441 is only useful if C, T1 and T2 are all "available". So we keep
442 instance decls that have been parsed from .hi files, but not yet
443 slurped in, in a pool called the 'gated instance pool'.
444 Each has its set of 'gates': {C, T1, T2} in the above example.
446 More precisely, the gates of a module are the types and classes
447 that are mentioned in:
450 b) the type of an Id that's mentioned in the source code
451 [includes constructors and selectors]
452 c) the RHS of a type synonym that is a gate
453 d) the superclasses of a class that is a gate
454 e) the context of an instance decl that is slurped in
456 We slurp in an instance decl from the gated instance pool iff
458 all its gates are either in the gates of the module,
459 or are a previously-loaded class.
461 The latter constraint is because there might have been an instance
462 decl slurped in during an earlier compilation, like this:
464 instance Foo a => Baz (Maybe a) where ...
466 In the module being compiled we might need (Baz (Maybe T)), where T
467 is defined in this module, and hence we need (Foo T). So @Foo@ becomes
468 a gate. But there's no way to 'see' that, so
470 we simply treat all previously-loaded classes as gates.
472 Consructors and class operations
473 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
474 When we import a declaration like
476 data T = T1 Wibble | T2 Wobble
478 we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless}
479 @T1@, @T2@ respectively are mentioned by the user program. If only
480 @T@ is mentioned we want only @T@ to be a gate; that way we don't suck
481 in useless instance decls for (say) @Eq Wibble@, when they can't
484 And that's just what (b) says: we only treat T1's type as a gate if
485 T1 is mentioned. getGates, which deals with decls we are slurping in,
486 has to be a bit careful, because a mention of T1 will slurp in T's whole
489 -----------------------------
490 @getGates@ takes a newly imported (and renamed) decl, and the free
491 vars of the source program, and extracts from the decl the gate names.
494 getGates :: FreeVars -- Things mentioned in the source program
495 -- Used for the cunning "constructors and
496 -- class ops" story described 10 lines above.
500 getGates source_fvs decl
501 = get_gates (\n -> n `elemNameSet` source_fvs) decl
503 get_gates is_used (ForeignType {tcdName = tycon}) = unitNameSet tycon
504 get_gates is_used (IfaceSig {tcdType = ty}) = extractHsTyNames ty
506 get_gates is_used (ClassDecl { tcdCtxt = ctxt, tcdName = cls, tcdTyVars = tvs, tcdSigs = sigs})
507 = (super_cls_and_sigs `addOneToNameSet` cls) `unionNameSets`
508 implicitClassGates cls
510 super_cls_and_sigs = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
512 get (ClassOpSig n _ ty _)
513 | is_used n = extractHsTyNames ty
514 | otherwise = emptyFVs
516 get_gates is_used (TySynonym {tcdTyVars = tvs, tcdSynRhs = ty})
517 = delListFromNameSet (extractHsTyNames ty) (hsTyVarNames tvs)
518 -- A type synonym type constructor isn't a "gate" for instance decls
520 get_gates is_used (TyData {tcdCtxt = ctxt, tcdName = tycon, tcdTyVars = tvs, tcdCons = cons})
521 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
523 `addOneToNameSet` tycon
525 get (ConDecl n _ tvs ctxt details _)
527 -- If the constructor is method, get fvs from all its fields
528 = delListFromNameSet (get_details details `plusFV`
529 extractHsCtxtTyNames ctxt)
531 get (ConDecl n _ tvs ctxt (RecCon fields) _)
532 -- Even if the constructor isn't mentioned, the fields
533 -- might be, as selectors. They can't mention existentially
534 -- bound tyvars (typechecker checks for that) so no need for
535 -- the deleteListFromNameSet part
536 = foldr (plusFV . get_field) emptyFVs fields
538 get other_con = emptyFVs
540 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
541 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
542 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
544 get_field (fs,t) | any is_used fs = get_bang t
545 | otherwise = emptyFVs
547 get_bang bty = extractHsTyNames (getBangType bty)
549 implicitClassGates :: Name -> FreeVars
550 implicitClassGates cls
551 -- If we load class Num, add Integer to the free gates
552 -- This takes account of the fact that Integer might be needed for
553 -- defaulting, but we don't want to load Integer (and all its baggage)
554 -- if there's no numeric stuff needed.
555 -- Similarly for class Fractional and Double
557 -- NB: adding T to the gates will force T to be loaded
559 -- NB: If we load (say) Floating, we'll end up loading Fractional too,
560 -- since Fractional is a superclass of Floating
561 | cls `hasKey` numClassKey = unitFV integerTyConName
562 | cls `hasKey` fractionalClassKey = unitFV doubleTyConName
563 | otherwise = emptyFVs
566 @getWiredInGates@ is just like @getGates@, but it sees a previously-loaded
567 thing rather than a declaration.
570 getWiredInGates :: TyThing -> FreeVars
571 -- The TyThing is one that we already have in our type environment, either
572 -- a) because the TyCon or Id is wired in, or
573 -- b) from a previous compile
574 -- Either way, we might have instance decls in the (persistent) collection
575 -- of parsed-but-not-slurped instance decls that should be slurped in.
576 -- This might be the first module that mentions both the type and the class
577 -- for that instance decl, even though both the type and the class were
578 -- mentioned in other modules, and hence are in the type environment
580 getWiredInGates (AnId the_id) = namesOfType (idType the_id)
581 getWiredInGates (AClass cl) = implicitClassGates (getName cl)
582 -- The superclasses must also be previously
583 -- loaded, and hence are automatically gates
584 -- All previously-loaded classes are automatically gates
585 -- See "The gating story" above
586 getWiredInGates (ATyCon tc)
587 | isSynTyCon tc = delListFromNameSet (namesOfType ty) (map getName tyvars)
588 | otherwise = unitFV (getName tc)
590 (tyvars,ty) = getSynTyConDefn tc
592 getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty
596 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameInstDecl)]
597 getImportedInstDecls gates
598 = -- First, load any orphan-instance modules that aren't aready loaded
599 -- Orphan-instance modules are recorded in the module dependecnies
600 getIfacesRn `thenRn` \ ifaces ->
603 [mod | (mod, (True, _)) <- fmToList (iImpModInfo ifaces)]
605 loadOrphanModules orphan_mods `thenRn_`
607 -- Now we're ready to grab the instance declarations
608 -- Find the un-gated ones and return them,
609 -- removing them from the bag kept in Ifaces
610 getIfacesRn `thenRn` \ ifaces ->
611 getTypeEnvRn `thenRn` \ lookup ->
614 | n `elemNameSet` gates = True
615 | otherwise = case lookup n of { Just (AClass c) -> True; other -> False }
616 -- See "The gating story" above for the AClass thing
618 (decls, new_insts) = selectGated available (iInsts ifaces)
620 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
622 traceRn (sep [text "getImportedInstDecls:",
623 nest 4 (fsep (map ppr gate_list)),
624 text "Slurped" <+> int (length decls) <+> text "instance declarations",
625 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
628 gate_list = nameSetToList gates
630 ppr_brief_inst_decl (mod, InstDecl inst_ty _ _ _ _)
632 HsForAllTy _ _ tau -> ppr tau
635 getImportedRules :: RnMG [(Module,RdrNameRuleDecl)]
637 | opt_IgnoreIfacePragmas = returnRn []
639 = getIfacesRn `thenRn` \ ifaces ->
640 getTypeEnvRn `thenRn` \ lookup ->
642 -- Slurp rules for anything that is slurped,
643 -- either now or previously
644 gates = iSlurp ifaces
645 available n = n `elemNameSet` gates || maybeToBool (lookup n)
646 (decls, new_rules) = selectGated available (iRules ifaces)
651 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
652 traceRn (sep [text "getImportedRules:",
653 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
656 selectGated :: (Name->Bool) -> GatedDecls d
657 -> ([(Module,d)], GatedDecls d)
658 selectGated available (decl_bag, n_slurped)
659 -- Select only those decls whose gates are *all* available
661 | opt_NoPruneDecls -- Just to try the effect of not gating at all
663 decls = foldrBag (\ (_,d) ds -> d:ds) [] decl_bag -- Grab them all
665 (decls, (emptyBag, n_slurped + length decls))
669 = case foldrBag select ([], emptyBag) decl_bag of
670 (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls))
672 select (gate_fn, decl) (yes, no)
673 | gate_fn available = (decl:yes, no)
674 | otherwise = (yes, (gate_fn,decl) `consBag` no)
678 %*********************************************************
680 \subsection{Getting in a declaration}
682 %*********************************************************
685 importDecl :: Name -> RnMG ImportDeclResult
687 data ImportDeclResult
690 | HereItIs (Module, RdrNameTyClDecl)
693 = -- STEP 1: Check if we've slurped it in while compiling this module
694 getIfacesRn `thenRn` \ ifaces ->
695 if name `elemNameSet` iSlurp ifaces then
696 returnRn AlreadySlurped
700 -- STEP 2: Check if it's already in the type environment
701 getTypeEnvRn `thenRn` \ lookup ->
702 case lookup name of {
704 | name `elemNameEnv` wiredInThingEnv
705 -> -- When we find a wired-in name we must load its home
706 -- module so that we find any instance decls lurking therein
707 loadHomeInterface wi_doc name `thenRn_`
708 returnRn (InTypeEnv ty_thing)
711 -> -- Very important: record that we've seen it
712 -- See comments with recordTypeEnvSlurp
713 setIfacesRn (recordTypeEnvSlurp ifaces ty_thing) `thenRn_`
714 returnRn (InTypeEnv ty_thing) ;
718 -- STEP 3: OK, we have to slurp it in from an interface file
719 -- First load the interface file
720 traceRn nd_doc `thenRn_`
721 loadHomeInterface nd_doc name `thenRn_`
722 getIfacesRn `thenRn` \ ifaces ->
724 -- STEP 4: Get the declaration out
726 (decls_map, _) = iDecls ifaces
728 case lookupNameEnv decls_map name of
729 Just (avail,_,decl) -> setIfacesRn (recordDeclSlurp ifaces avail) `thenRn_`
730 returnRn (HereItIs decl)
732 Nothing -> addErrRn (getDeclErr name) `thenRn_`
733 returnRn AlreadySlurped
736 wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name
737 nd_doc = ptext SLIT("need decl for") <+> ppr name
742 %********************************************************
744 \subsection{Checking usage information}
746 %********************************************************
748 @recompileRequired@ is called from the HscMain. It checks whether
749 a recompilation is required. It needs access to the persistent state,
750 finder, etc, because it may have to load lots of interface files to
751 check their versions.
754 type RecompileRequired = Bool
755 upToDate = False -- Recompile not required
756 outOfDate = True -- Recompile required
758 recompileRequired :: FilePath -- Only needed for debug msgs
759 -> ModIface -- Old interface
760 -> RnMG RecompileRequired
761 recompileRequired iface_path iface
762 = traceHiDiffsRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_`
764 -- Source code unchanged and no errors yet... carry on
765 checkList [checkModUsage u | u <- mi_usages iface]
767 checkList :: [RnMG RecompileRequired] -> RnMG RecompileRequired
768 checkList [] = returnRn upToDate
769 checkList (check:checks) = check `thenRn` \ recompile ->
777 checkModUsage :: ImportVersion Name -> RnMG RecompileRequired
778 -- Given the usage information extracted from the old
779 -- M.hi file for the module being compiled, figure out
780 -- whether M needs to be recompiled.
782 checkModUsage (mod_name, _, _, NothingAtAll)
783 -- If CurrentModule.hi contains
785 -- then that simply records that Foo lies below CurrentModule in the
786 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
787 -- In this case we don't even want to open Foo's interface.
788 = up_to_date (ptext SLIT("Nothing used from:") <+> ppr mod_name)
790 checkModUsage (mod_name, _, is_boot, whats_imported)
791 = -- Load the imported interface is possible
792 -- We use tryLoadInterface, because failure is not an error
793 -- (might just be that the old .hi file for this module is out of date)
794 -- We use ImportByUser/ImportByUserSource as the 'from' flag,
795 -- a) because we need to know whether to load the .hi-boot file
796 -- b) because loadInterface things matters are amiss if we
797 -- ImportBySystem an interface it knows nothing about
799 doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
800 from | is_boot = ImportByUserSource
801 | otherwise = ImportByUser
803 traceHiDiffsRn (text "Checking usages for module" <+> ppr mod_name) `thenRn_`
804 tryLoadInterface doc_str mod_name from `thenRn` \ (iface, maybe_err) ->
807 Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"),
809 -- Couldn't find or parse a module mentioned in the
810 -- old interface file. Don't complain -- it might just be that
811 -- the current module doesn't need that import and it's been deleted
815 new_vers = mi_version iface
816 new_decl_vers = vers_decls new_vers
818 case whats_imported of { -- NothingAtAll dealt with earlier
820 Everything old_mod_vers -> checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
822 out_of_date (ptext SLIT("...and I needed the whole module"))
826 Specifically old_mod_vers maybe_old_export_vers old_decl_vers old_rule_vers ->
829 checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile ->
830 if not recompile then
835 if checkExportList maybe_old_export_vers new_vers then
836 out_of_date (ptext SLIT("Export list changed"))
840 if old_rule_vers /= vers_rules new_vers then
841 out_of_date (ptext SLIT("Rules changed"))
844 -- CHECK ITEMS ONE BY ONE
845 checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenRn` \ recompile ->
847 returnRn outOfDate -- This one failed, so just bail out now
849 up_to_date (ptext SLIT("...but the bits I use haven't."))
853 ------------------------
854 checkModuleVersion old_mod_vers new_vers
855 | vers_module new_vers == old_mod_vers
856 = up_to_date (ptext SLIT("Module version unchanged"))
859 = out_of_date (ptext SLIT("Module version has changed"))
861 ------------------------
862 checkExportList Nothing new_vers = upToDate
863 checkExportList (Just v) new_vers = v /= vers_exports new_vers
865 ------------------------
866 checkEntityUsage new_vers (name,old_vers)
867 = case lookupNameEnv new_vers name of
869 Nothing -> -- We used it before, but it ain't there now
870 out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
872 Just new_vers -- It's there, but is it up to date?
873 | new_vers == old_vers -> traceHiDiffsRn (text "Up to date" <+> ppr name <+> parens (ppr new_vers)) `thenRn_`
875 | otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name, ppr
876 old_vers, ptext SLIT("->"), ppr new_vers])
878 up_to_date msg = traceHiDiffsRn msg `thenRn_` returnRn upToDate
879 out_of_date msg = traceHiDiffsRn msg `thenRn_` returnRn outOfDate
883 %*********************************************************
887 %*********************************************************
891 = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
892 ptext SLIT("from module") <+> quotes (ppr (nameModule name))