2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnIfaces]{Cacheing and Renaming of Interfaces}
10 getInterfaceExports, getDeferredDecls,
11 getImportedInstDecls, getImportedRules,
12 lookupFixityRn, loadHomeInterface,
13 importDecl, ImportDeclResult(..), recordLocalSlurps, loadBuiltinRules,
14 mkImportExportInfo, getSlurped,
16 checkModUsage, outOfDate, upToDate,
18 getDeclBinders, getDeclSysBinders,
19 removeContext -- removeContext probably belongs somewhere else
22 #include "HsVersions.h"
24 import CmdLineOpts ( opt_NoPruneDecls, opt_NoPruneTyDecls, opt_IgnoreIfacePragmas )
25 import HsSyn ( HsDecl(..), TyClDecl(..), InstDecl(..), IfaceSig(..),
26 HsType(..), ConDecl(..), IE(..), ConDetails(..), Sig(..),
27 ForeignDecl(..), ForKind(..), isDynamicExtName,
28 FixitySig(..), RuleDecl(..),
29 isClassOpSig, DeprecDecl(..)
31 import HsImpExp ( ieNames )
32 import CoreSyn ( CoreRule )
33 import BasicTypes ( Version, NewOrData(..) )
34 import RdrHsSyn ( RdrNameHsDecl, RdrNameInstDecl, RdrNameRuleDecl,
35 RdrNameDeprecation, RdrNameIE,
40 import ParseIface ( parseIface, IfaceStuff(..) )
42 import Name ( Name {-instance NamedThing-}, nameOccName,
43 nameModule, isLocallyDefined,
44 isWiredInName, nameUnique, NamedThing(..)
46 import Module ( Module, moduleString, pprModule,
47 mkVanillaModule, pprModuleName,
48 moduleUserString, moduleName, isLocalModule,
49 ModuleName, WhereFrom(..),
51 import RdrName ( RdrName, rdrNameOcc )
53 import SrcLoc ( mkSrcLoc, SrcLoc )
54 import PrelInfo ( cCallishTyKeys )
55 import Maybes ( MaybeErr(..), maybeToBool, orElse )
56 import Unique ( Uniquable(..) )
57 import StringBuffer ( hGetStringBuffer )
58 import FastString ( mkFastString )
59 import ErrUtils ( Message )
60 import Util ( sortLt )
70 %*********************************************************
72 \subsection{Loading a new interface file}
74 %*********************************************************
77 loadHomeInterface :: SDoc -> Name -> RnM d Ifaces
78 loadHomeInterface doc_str name
79 = loadInterface doc_str (moduleName (nameModule name)) ImportBySystem
81 loadOrphanModules :: [ModuleName] -> RnM d ()
82 loadOrphanModules mods
83 | null mods = returnRn ()
84 | otherwise = traceRn (text "Loading orphan modules:" <+>
85 fsep (map pprModuleName mods)) `thenRn_`
86 mapRn_ load mods `thenRn_`
89 load mod = loadInterface (mk_doc mod) mod ImportBySystem
90 mk_doc mod = pprModuleName mod <+> ptext SLIT("is a orphan-instance module")
93 loadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d Ifaces
94 loadInterface doc mod from
95 = tryLoadInterface doc mod from `thenRn` \ (ifaces, maybe_err) ->
97 Nothing -> returnRn ifaces
98 Just err -> failWithRn ifaces err
100 tryLoadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d (Ifaces, Maybe Message)
101 -- Returns (Just err) if an error happened
102 -- Guarantees to return with iImpModInfo m --> (... Just cts)
103 -- (If the load fails, we plug in a vanilla placeholder
104 tryLoadInterface doc_str mod_name from
105 = getIfacesRn `thenRn` \ ifaces ->
107 mod_map = iImpModInfo ifaces
108 mod_info = lookupFM mod_map mod_name
110 hi_boot_file = case from of {
111 ImportByUser -> False ; -- Not hi-boot
112 ImportByUserSource -> True ; -- hi-boot
115 Just (_, is_boot, _) -> is_boot
118 -- We're importing a module we know absolutely
119 -- nothing about, so we assume it's from
120 -- another package, where we aren't doing
121 -- dependency tracking. So it won't be a hi-boot file.
123 redundant_source_import
124 = case (from, mod_info) of
125 (ImportByUserSource, Just (_,False,_)) -> True
128 -- CHECK WHETHER WE HAVE IT ALREADY
131 -> -- We're read it already so don't re-read it
132 returnRn (ifaces, Nothing) ;
136 -- Issue a warning for a redundant {- SOURCE -} import
137 -- NB that we arrange to read all the ordinary imports before
138 -- any of the {- SOURCE -} imports
139 warnCheckRn (not redundant_source_import)
140 (warnRedundantSourceImport mod_name) `thenRn_`
142 -- READ THE MODULE IN
143 findAndReadIface doc_str mod_name hi_boot_file `thenRn` \ read_result ->
144 case read_result of {
145 Left err -> -- Not found, so add an empty export env to the Ifaces map
146 -- so that we don't look again
148 mod = mkVanillaModule mod_name
149 new_mod_map = addToFM mod_map mod_name (False, False, Just (mod, 0, 0, 0, from, []))
150 new_ifaces = ifaces { iImpModInfo = new_mod_map }
152 setIfacesRn new_ifaces `thenRn_`
153 returnRn (new_ifaces, Just err) ;
158 -- LOAD IT INTO Ifaces
160 -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
161 --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
162 -- If we do loadExport first the wrong info gets into the cache (unless we
163 -- explicitly tag each export which seems a bit of a bore)
165 getModuleRn `thenRn` \ this_mod_nm ->
169 -- Sanity check. If we're system-importing a module we know nothing at all
170 -- about, it should be from a different package to this one
171 WARN( not (maybeToBool mod_info) &&
172 case from of { ImportBySystem -> True; other -> False } &&
175 foldlRn (loadDecl mod) (iDecls ifaces) (pi_decls iface) `thenRn` \ new_decls ->
176 foldlRn (loadInstDecl mod) (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
177 loadRules mod (iRules ifaces) (pi_rules iface) `thenRn` \ new_rules ->
178 loadFixDecls mod_name (iFixes ifaces) (pi_fixity iface) `thenRn` \ new_fixities ->
179 foldlRn (loadDeprec mod) (iDeprecs ifaces) (pi_deprecs iface) `thenRn` \ new_deprecs ->
180 mapRn (loadExport this_mod_nm) (pi_exports iface) `thenRn` \ avails_s ->
182 -- For an explicit user import, add to mod_map info about
183 -- the things the imported module depends on, extracted
184 -- from its usage info.
185 mod_map1 = case from of
186 ImportByUser -> addModDeps mod (pi_usages iface) mod_map
189 -- Now add info about this module
190 mod_map2 = addToFM mod_map1 mod_name mod_details
191 cts = (pi_mod iface, pi_vers iface,
192 fst (pi_fixity iface), fst (pi_rules iface),
193 from, concat avails_s)
194 mod_details = (pi_orphan iface, hi_boot_file, Just cts)
196 new_ifaces = ifaces { iImpModInfo = mod_map2,
198 iFixes = new_fixities,
201 iDeprecs = new_deprecs }
203 setIfacesRn new_ifaces `thenRn_`
204 returnRn (new_ifaces, Nothing)
207 -----------------------------------------------------
208 -- Adding module dependencies from the
209 -- import decls in the interface file
210 -----------------------------------------------------
212 addModDeps :: Module -> [ImportVersion a]
213 -> ImportedModuleInfo -> ImportedModuleInfo
214 -- (addModDeps M ivs deps)
215 -- We are importing module M, and M.hi contains 'import' decls given by ivs
216 addModDeps mod new_deps mod_deps
217 = foldr add mod_deps filtered_new_deps
219 -- Don't record dependencies when importing a module from another package
220 -- Except for its descendents which contain orphans,
221 -- and in that case, forget about the boot indicator
223 | isLocalModule mod = [ (imp_mod, (has_orphans, is_boot, Nothing))
224 | (imp_mod, has_orphans, is_boot, _) <- new_deps
226 | otherwise = [ (imp_mod, (True, False, Nothing))
227 | (imp_mod, has_orphans, _, _) <- new_deps,
230 add (imp_mod, dep) deps = addToFM_C combine deps imp_mod dep
232 combine old@(_, old_is_boot, cts) new
233 | maybeToBool cts || not old_is_boot = old -- Keep the old info if it's already loaded
234 -- or if it's a non-boot pending load
235 | otherwise = new -- Otherwise pick new info
238 -----------------------------------------------------
239 -- Loading the export list
240 -----------------------------------------------------
242 loadExport :: ModuleName -> ExportItem -> RnM d [AvailInfo]
243 loadExport this_mod (mod, entities)
244 | mod == this_mod = returnRn []
245 -- If the module exports anything defined in this module, just ignore it.
246 -- Reason: otherwise it looks as if there are two local definition sites
247 -- for the thing, and an error gets reported. Easiest thing is just to
248 -- filter them out up front. This situation only arises if a module
249 -- imports itself, or another module that imported it. (Necessarily,
250 -- this invoves a loop.) Consequence: if you say
255 -- module B( AType ) where
256 -- import {-# SOURCE #-} A( AType )
258 -- then you'll get a 'B does not export AType' message. A bit bogus
259 -- but it's a bogus thing to do!
262 = mapRn (load_entity mod) entities
264 new_name mod occ = mkImportedGlobalName mod occ
266 load_entity mod (Avail occ)
267 = new_name mod occ `thenRn` \ name ->
268 returnRn (Avail name)
269 load_entity mod (AvailTC occ occs)
270 = new_name mod occ `thenRn` \ name ->
271 mapRn (new_name mod) occs `thenRn` \ names ->
272 returnRn (AvailTC name names)
275 -----------------------------------------------------
276 -- Loading type/class/value decls
277 -----------------------------------------------------
281 -> (Version, RdrNameHsDecl)
284 loadDecl mod decls_map (version, decl)
285 = getDeclBinders new_name decl `thenRn` \ maybe_avail ->
286 case maybe_avail of {
287 Nothing -> returnRn decls_map; -- No bindings
290 getDeclSysBinders new_name decl `thenRn` \ sys_bndrs ->
292 full_avail = addSysAvails avail sys_bndrs
293 -- Add the sys-binders to avail. When we import the decl,
294 -- it's full_avail that will get added to the 'already-slurped' set (iSlurp)
295 -- If we miss out sys-binders, we'll read the decl multiple times!
297 main_name = availName avail
298 new_decls_map = foldl add_decl decls_map
299 [ (name, (version, full_avail, name==main_name, (mod, decl')))
300 | name <- availNames full_avail]
301 add_decl decls_map (name, stuff)
302 = WARN( name `elemNameEnv` decls_map, ppr name )
303 addToNameEnv decls_map name stuff
305 returnRn new_decls_map
308 -- newTopBinder puts into the cache the binder with the
309 -- module information set correctly. When the decl is later renamed,
310 -- the binding site will thereby get the correct module.
311 -- There maybe occurrences that don't have the correct Module, but
312 -- by the typechecker will propagate the binding definition to all
313 -- the occurrences, so that doesn't matter
314 new_name rdr_name loc = newTopBinder mod (rdrNameOcc rdr_name)
317 If a signature decl is being loaded, and optIgnoreIfacePragmas is on,
318 we toss away unfolding information.
320 Also, if the signature is loaded from a module we're importing from source,
321 we do the same. This is to avoid situations when compiling a pair of mutually
322 recursive modules, peering at unfolding info in the interface file of the other,
323 e.g., you compile A, it looks at B's interface file and may as a result change
324 its interface file. Hence, B is recompiled, maybe changing its interface file,
325 which will the unfolding info used in A to become invalid. Simple way out is to
326 just ignore unfolding info.
328 [Jan 99: I junked the second test above. If we're importing from an hi-boot
329 file there isn't going to *be* any pragma info. Maybe the above comment
330 dates from a time where we picked up a .hi file first if it existed?]
333 SigD (IfaceSig name tp ls loc) | opt_IgnoreIfacePragmas
334 -> SigD (IfaceSig name tp [] loc)
337 -----------------------------------------------------
338 -- Loading fixity decls
339 -----------------------------------------------------
341 loadFixDecls mod_name fixity_env (version, decls)
342 | null decls = returnRn fixity_env
345 = mapRn (loadFixDecl mod_name) decls `thenRn` \ to_add ->
346 returnRn (addListToNameEnv fixity_env to_add)
348 loadFixDecl mod_name sig@(FixitySig rdr_name fixity loc)
349 = mkImportedGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
350 returnRn (name, FixitySig name fixity loc)
353 -----------------------------------------------------
354 -- Loading instance decls
355 -----------------------------------------------------
357 loadInstDecl :: Module
361 loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
363 -- Find out what type constructors and classes are "gates" for the
364 -- instance declaration. If all these "gates" are slurped in then
365 -- we should slurp the instance decl too.
367 -- We *don't* want to count names in the context part as gates, though.
369 -- instance Foo a => Baz (T a) where ...
371 -- Here the gates are Baz and T, but *not* Foo.
373 munged_inst_ty = removeContext inst_ty
374 free_names = extractHsTyRdrNames munged_inst_ty
376 setModuleRn (moduleName mod) $
377 mapRn mkImportedGlobalFromRdrName free_names `thenRn` \ gate_names ->
378 returnRn ((mkNameSet gate_names, (mod, InstD decl)) `consBag` insts)
381 -- In interface files, the instance decls now look like
382 -- forall a. Foo a -> Baz (T a)
383 -- so we have to strip off function argument types as well
384 -- as the bit before the '=>' (which is always empty in interface files)
385 removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
386 removeContext ty = removeFuns ty
388 removeFuns (HsFunTy _ ty) = removeFuns ty
392 -----------------------------------------------------
394 -----------------------------------------------------
396 loadRules :: Module -> IfaceRules
397 -> (Version, [RdrNameRuleDecl])
399 loadRules mod rule_bag (version, rules)
400 | null rules || opt_IgnoreIfacePragmas
403 = setModuleRn mod_name $
404 mapRn (loadRule mod) rules `thenRn` \ new_rules ->
405 returnRn (rule_bag `unionBags` listToBag new_rules)
407 mod_name = moduleName mod
409 loadRule :: Module -> RdrNameRuleDecl -> RnM d GatedDecl
410 -- "Gate" the rule simply by whether the rule variable is
411 -- needed. We can refine this later.
412 loadRule mod decl@(IfaceRule _ _ var _ _ src_loc)
413 = mkImportedGlobalFromRdrName var `thenRn` \ var_name ->
414 returnRn (unitNameSet var_name, (mod, RuleD decl))
416 loadBuiltinRules :: [(RdrName, CoreRule)] -> RnMG ()
417 loadBuiltinRules builtin_rules
418 = getIfacesRn `thenRn` \ ifaces ->
419 mapRn loadBuiltinRule builtin_rules `thenRn` \ rule_decls ->
420 setIfacesRn (ifaces { iRules = iRules ifaces `unionBags` listToBag rule_decls })
422 loadBuiltinRule (var, rule)
423 = mkImportedGlobalFromRdrName var `thenRn` \ var_name ->
424 returnRn (unitNameSet var_name, (nameModule var_name, RuleD (IfaceRuleOut var rule)))
427 -----------------------------------------------------
428 -- Loading Deprecations
429 -----------------------------------------------------
431 loadDeprec :: Module -> DeprecationEnv -> RdrNameDeprecation -> RnM d DeprecationEnv
432 loadDeprec mod deprec_env (Deprecation (IEModuleContents _) txt _)
433 = traceRn (text "module deprecation not yet implemented:" <+> ppr mod <> colon <+> ppr txt) `thenRn_`
434 -- SUP: TEMPORARY HACK, ignoring module deprecations for now
437 loadDeprec mod deprec_env (Deprecation ie txt _)
438 = setModuleRn (moduleName mod) $
439 mapRn mkImportedGlobalFromRdrName (ieNames ie) `thenRn` \ names ->
440 traceRn (text "loaded deprecation(s) for" <+> hcat (punctuate comma (map ppr names)) <> colon <+> ppr txt) `thenRn_`
441 returnRn (extendNameEnv deprec_env (zip names (repeat txt)))
445 %********************************************************
447 \subsection{Checking usage information}
449 %********************************************************
455 checkModUsage :: [ImportVersion OccName] -> RnMG Bool
456 -- Given the usage information extracted from the old
457 -- M.hi file for the module being compiled, figure out
458 -- whether M needs to be recompiled.
460 checkModUsage [] = returnRn upToDate -- Yes! Everything is up to date!
462 checkModUsage ((mod_name, _, _, NothingAtAll) : rest)
463 -- If CurrentModule.hi contains
465 -- then that simply records that Foo lies below CurrentModule in the
466 -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
467 -- In this case we don't even want to open Foo's interface.
468 = traceRn (ptext SLIT("Nothing used from:") <+> ppr mod_name) `thenRn_`
469 checkModUsage rest -- This one's ok, so check the rest
471 checkModUsage ((mod_name, _, _, whats_imported) : rest)
472 = tryLoadInterface doc_str mod_name ImportBySystem `thenRn` \ (ifaces, maybe_err) ->
474 Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"),
475 pprModuleName mod_name]) ;
476 -- Couldn't find or parse a module mentioned in the
477 -- old interface file. Don't complain -- it might just be that
478 -- the current module doesn't need that import and it's been deleted
482 (_, new_mod_vers, new_fix_vers, new_rule_vers, _, _)
483 = case lookupFM (iImpModInfo ifaces) mod_name of
484 Just (_, _, Just stuff) -> stuff
486 old_mod_vers = case whats_imported of
488 Specifically v _ _ _ -> v
489 -- NothingAtAll case dealt with by previous eqn for checkModUsage
491 -- If the module version hasn't changed, just move on
492 if new_mod_vers == old_mod_vers then
493 traceRn (sep [ptext SLIT("Module version unchanged:"), pprModuleName mod_name])
494 `thenRn_` checkModUsage rest
496 traceRn (sep [ptext SLIT("Module version has changed:"), pprModuleName mod_name])
498 -- Module version changed, so check entities inside
500 -- If the usage info wants to say "I imported everything from this module"
501 -- it does so by making whats_imported equal to Everything
502 -- In that case, we must recompile
503 case whats_imported of { -- NothingAtAll dealt with earlier
506 -> out_of_date (ptext SLIT("...and I needed the whole module")) ;
508 Specifically _ old_fix_vers old_rule_vers old_local_vers ->
510 if old_fix_vers /= new_fix_vers then
511 out_of_date (ptext SLIT("Fixities changed"))
512 else if old_rule_vers /= new_rule_vers then
513 out_of_date (ptext SLIT("Rules changed"))
515 -- Non-empty usage list, so check item by item
516 checkEntityUsage mod_name (iDecls ifaces) old_local_vers `thenRn` \ up_to_date ->
518 traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_`
519 checkModUsage rest -- This one's ok, so check the rest
521 returnRn outOfDate -- This one failed, so just bail out now
524 doc_str = sep [ptext SLIT("need version info for"), pprModuleName mod_name]
527 checkEntityUsage mod decls []
528 = returnRn upToDate -- Yes! All up to date!
530 checkEntityUsage mod decls ((occ_name,old_vers) : rest)
531 = mkImportedGlobalName mod occ_name `thenRn` \ name ->
532 case lookupNameEnv decls name of
534 Nothing -> -- We used it before, but it ain't there now
535 out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
537 Just (new_vers,_,_,_) -- It's there, but is it up to date?
538 | new_vers == old_vers
539 -- Up to date, so check the rest
540 -> checkEntityUsage mod decls rest
543 -- Out of date, so bale out
544 -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
546 out_of_date msg = traceRn msg `thenRn_` returnRn outOfDate
550 %*********************************************************
552 \subsection{Getting in a declaration}
554 %*********************************************************
557 importDecl :: Name -> RnMG ImportDeclResult
559 data ImportDeclResult
563 | HereItIs (Module, RdrNameHsDecl)
566 = getSlurped `thenRn` \ already_slurped ->
567 if name `elemNameSet` already_slurped then
568 returnRn AlreadySlurped -- Already dealt with
570 else if isLocallyDefined name then -- Don't bring in decls from
571 -- the renamed module's own interface file
572 addWarnRn (importDeclWarn name) `thenRn_`
573 returnRn AlreadySlurped
575 else if isWiredInName name then
576 -- When we find a wired-in name we must load its
577 -- home module so that we find any instance decls therein
578 loadHomeInterface doc name `thenRn_`
581 else getNonWiredInDecl name
583 doc = ptext SLIT("need home module for wired in thing") <+> ppr name
586 {- I don't think this is necessary any more; SLPJ May 00
588 | name `elemNameSet` source_binders = returnRn ()
589 -- When compiling the prelude, a wired-in thing may
590 -- be defined in this module, in which case we don't
591 -- want to load its home module!
592 -- Using 'isLocallyDefined' doesn't work because some of
593 -- the free variables returned are simply 'listTyCon_Name',
594 -- with a system provenance. We could look them up every time
595 -- but that seems a waste.
596 | otherwise = loadHomeInterface doc name `thenRn_`
600 getNonWiredInDecl :: Name -> RnMG ImportDeclResult
601 getNonWiredInDecl needed_name
602 = traceRn doc_str `thenRn_`
603 loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
604 case lookupNameEnv (iDecls ifaces) needed_name of
606 Just (version, avail, is_tycon_name, decl@(_, TyClD (TyData DataType _ _ _ _ ncons _ _ _)))
607 -- This case deals with deferred import of algebraic data types
609 | not opt_NoPruneTyDecls
611 && (opt_IgnoreIfacePragmas || ncons > 1)
612 -- We only defer if imported interface pragmas are ingored
613 -- or if it's not a product type.
614 -- Sole reason: The wrapper for a strict function may need to look
615 -- inside its arg, and hence need to see its arg type's constructors.
617 && not (getUnique tycon_name `elem` cCallishTyKeys)
618 -- Never defer ccall types; we have to unbox them,
619 -- and importing them does no harm
621 -> -- OK, so we're importing a deferrable data type
622 if needed_name == tycon_name then
623 -- The needed_name is the TyCon of a data type decl
624 -- Record that it's slurped, put it in the deferred set
625 -- and don't return a declaration at all
626 setIfacesRn (recordSlurp (ifaces {iDeferred = iDeferred ifaces
627 `addOneToNameSet` tycon_name})
628 version (AvailTC needed_name [needed_name])) `thenRn_`
631 -- The needed name is a constructor of a data type decl,
632 -- getting a constructor, so remove the TyCon from the deferred set
633 -- (if it's there) and return the full declaration
634 setIfacesRn (recordSlurp (ifaces {iDeferred = iDeferred ifaces
635 `delFromNameSet` tycon_name})
636 version avail) `thenRn_`
637 returnRn (HereItIs decl)
639 tycon_name = availName avail
641 Just (version,avail,_,decl)
642 -> setIfacesRn (recordSlurp ifaces version avail) `thenRn_`
643 returnRn (HereItIs decl)
646 -> addErrRn (getDeclErr needed_name) `thenRn_`
647 returnRn AlreadySlurped
649 doc_str = ptext SLIT("need decl for") <+> ppr needed_name
651 getDeferredDecls :: RnMG [(Module, RdrNameHsDecl)]
653 = getIfacesRn `thenRn` \ ifaces ->
655 decls_map = iDecls ifaces
656 deferred_names = nameSetToList (iDeferred ifaces)
657 get_abstract_decl n = case lookupNameEnv decls_map n of
658 Just (_, _, _, decl) -> decl
660 traceRn (sep [text "getDeferredDecls", nest 4 (fsep (map ppr deferred_names))]) `thenRn_`
661 returnRn (map get_abstract_decl deferred_names)
664 @getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
665 It behaves exactly as if the wired in decl were actually in an interface file.
668 \item if the wired-in name is a data type constructor or a data constructor,
669 it brings in the type constructor and all the data constructors; and
670 marks as ``occurrences'' any free vars of the data con.
672 \item similarly for synonum type constructor
674 \item if the wired-in name is another wired-in Id, it marks as ``occurrences''
675 the free vars of the Id's type.
677 \item it loads the interface file for the wired-in thing for the
678 sole purpose of making sure that its instance declarations are available
680 All this is necessary so that we know all types that are ``in play'', so
681 that we know just what instances to bring into scope.
686 %*********************************************************
688 \subsection{Getting what a module exports}
690 %*********************************************************
692 @getInterfaceExports@ is called only for directly-imported modules.
695 getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
696 getInterfaceExports mod_name from
697 = loadInterface doc_str mod_name from `thenRn` \ ifaces ->
698 case lookupFM (iImpModInfo ifaces) mod_name of
699 Just (_, _, Just (mod, _, _, _, _, avails)) -> returnRn (mod, avails)
700 -- loadInterface always puts something in the map
701 -- even if it's a fake
703 doc_str = sep [pprModuleName mod_name, ptext SLIT("is directly imported")]
707 %*********************************************************
709 \subsection{Instance declarations are handled specially}
711 %*********************************************************
714 getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
715 getImportedInstDecls gates
716 = -- First, load any orphan-instance modules that aren't aready loaded
717 -- Orphan-instance modules are recorded in the module dependecnies
718 getIfacesRn `thenRn` \ ifaces ->
721 [mod | (mod, (True, _, Nothing)) <- fmToList (iImpModInfo ifaces)]
723 loadOrphanModules orphan_mods `thenRn_`
725 -- Now we're ready to grab the instance declarations
726 -- Find the un-gated ones and return them,
727 -- removing them from the bag kept in Ifaces
728 getIfacesRn `thenRn` \ ifaces ->
730 (decls, new_insts) = selectGated gates (iInsts ifaces)
732 setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
734 traceRn (sep [text "getImportedInstDecls:",
735 nest 4 (fsep (map ppr gate_list)),
736 text "Slurped" <+> int (length decls) <+> text "instance declarations",
737 nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
740 gate_list = nameSetToList gates
742 ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
744 HsForAllTy _ _ tau -> ppr tau
747 getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
749 | opt_IgnoreIfacePragmas = returnRn []
751 = getIfacesRn `thenRn` \ ifaces ->
753 gates = iSlurp ifaces -- Anything at all that's been slurped
754 rules = iRules ifaces
755 (decls, new_rules) = selectGated gates rules
760 setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
761 traceRn (sep [text "getImportedRules:",
762 text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
765 selectGated gates decl_bag
766 -- Select only those decls whose gates are *all* in 'gates'
768 | opt_NoPruneDecls -- Just to try the effect of not gating at all
769 = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
773 = foldrBag select ([], emptyBag) decl_bag
775 select (reqd, decl) (yes, no)
776 | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
777 | otherwise = (yes, (reqd,decl) `consBag` no)
779 lookupFixityRn :: Name -> RnMS Fixity
781 | isLocallyDefined name
782 = getFixityEnv `thenRn` \ local_fix_env ->
783 returnRn (lookupFixity local_fix_env name)
785 | otherwise -- Imported
786 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
787 -- and consulting the Ifaces that comes back from that, because the interface
788 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
789 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
790 -- right away (after all, it's possible that nothing from B will be used).
791 -- When we come across a use of 'f', we need to know its fixity, and it's then,
792 -- and only then, that we load B.hi. That is what's happening here.
793 = loadHomeInterface doc name `thenRn` \ ifaces ->
794 returnRn (lookupFixity (iFixes ifaces) name)
796 doc = ptext SLIT("Checking fixity for") <+> ppr name
800 %*********************************************************
802 \subsection{Keeping track of what we've slurped, and version numbers}
804 %*********************************************************
806 getImportVersions figures out what the ``usage information'' for this
807 moudule is; that is, what it must record in its interface file as the
808 things it uses. It records:
811 \item (a) anything reachable from its body code
812 \item (b) any module exported with a @module Foo@
813 \item (c) anything reachable from an exported item
816 Why (b)? Because if @Foo@ changes then this module's export list
817 will change, so we must recompile this module at least as far as
818 making a new interface file --- but in practice that means complete
821 Why (c)? Consider this:
823 module A( f, g ) where | module B( f ) where
824 import B( f ) | f = h 3
828 Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
829 @A@'s usages? Our idea is that we aren't going to touch A.hi if it is
830 *identical* to what it was before. If anything about @B.f@ changes
831 than anyone who imports @A@ should be recompiled in case they use
832 @B.f@ (they'll get an early exit if they don't). So, if anything
833 about @B.f@ changes we'd better make sure that something in A.hi
834 changes, and the convenient way to do that is to record the version
835 number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
836 complete recompiation of A, which is overkill but it's the only way to
837 write a new, slightly different, A.hi.
839 But the example is tricker. Even if @B.f@ doesn't change at all,
840 @B.h@ may do so, and this change may not be reflected in @f@'s version
841 number. But with -O, a module that imports A must be recompiled if
842 @B.h@ changes! So A must record a dependency on @B.h@. So we treat
843 the occurrence of @B.f@ in the export list *just as if* it were in the
844 code of A, and thereby haul in all the stuff reachable from it.
846 [NB: If B was compiled with -O, but A isn't, we should really *still*
847 haul in all the unfoldings for B, in case the module that imports A *is*
848 compiled with -O. I think this is the case.]
850 Even if B is used at all we get a usage line for B
851 import B <n> :: ... ;
852 in A.hi, to record the fact that A does import B. This is used to decide
853 to look to look for B.hi rather than B.hi-boot when compiling a module that
854 imports A. This line says that A imports B, but uses nothing in it.
855 So we'll get an early bale-out when compiling A if B's version changes.
858 mkImportExportInfo :: ModuleName -- Name of this module
859 -> Avails -- Info about exports
860 -> Maybe [RdrNameIE] -- The export header
861 -> RnMG ([ExportItem], -- Export info for iface file; sorted
862 [ImportVersion OccName]) -- Import info for iface file; sorted
863 -- Both results are sorted into canonical order to
864 -- reduce needless wobbling of interface files
866 mkImportExportInfo this_mod export_avails exports
867 = getIfacesRn `thenRn` \ ifaces ->
869 export_all_mods = case exports of
871 Just es -> [mod | IEModuleContents mod <- es,
874 mod_map = iImpModInfo ifaces
875 imp_names = iVSlurp ifaces
877 -- mv_map groups together all the things imported from a particular module.
878 mv_map :: FiniteMap ModuleName [(OccName,Version)]
879 mv_map = foldr add_mv emptyFM imp_names
881 add_mv (name, version) mv_map = addItem mv_map (moduleName (nameModule name))
882 (nameOccName name, version)
884 -- Build the result list by adding info for each module.
885 -- For (a) a library module, we don't record it at all unless it contains orphans
886 -- (We must never lose track of orphans.)
888 -- (b) a source-imported module, don't record the dependency at all
890 -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
891 -- *all* the module's dependencies other than the loop-breakers. We use
892 -- this info in findAndReadInterface to decide whether to look for a .hi file or
895 -- This means we won't track version changes, or orphans, from .hi-boot files.
896 -- The former is potentially rather bad news. It could be fixed by recording
897 -- whether something is a boot file along with the usage info for it, but
898 -- I can't be bothered just now.
900 mk_imp_info mod_name (has_orphans, is_boot, contents) so_far
901 | mod_name == this_mod -- Check if M appears in the set of modules 'below' M
902 -- This seems like a convenient place to check
903 = WARN( not is_boot, ptext SLIT("Wierd:") <+> ppr this_mod <+>
904 ptext SLIT("imports itself (perhaps indirectly)") )
909 go_for_it exports = (mod_name, has_orphans, is_boot, exports)
913 Nothing -> -- We didn't even open the interface
914 -- This happens when a module, Foo, that we explicitly imported has
915 -- 'import Baz' in its interface file, recording that Baz is below
916 -- Foo in the module dependency hierarchy. We want to propagate this
917 -- information. The Nothing says that we didn't even open the interface
918 -- file but we must still propagate the dependeny info.
919 -- The module in question must be a local module (in the same package)
920 go_for_it NothingAtAll
922 Just (mod, mod_vers, fix_vers, rule_vers, how_imported, _)
923 | is_sys_import && is_lib_module && not has_orphans
926 | is_lib_module -- Record the module but not detailed
927 || mod_name `elem` export_all_mods -- version information for the imports
928 -> go_for_it (Everything mod_vers)
931 -> case lookupFM mv_map mod_name of
932 Just whats_imported -> go_for_it (Specifically mod_vers fix_vers rule_vers
933 (sortImport whats_imported))
934 Nothing -> go_for_it NothingAtAll
935 -- This happens if you have
937 -- but don't actually *use* anything from Foo
938 -- In which case record an empty dependency list
940 is_lib_module = not (isLocalModule mod)
941 is_sys_import = case how_imported of
942 ImportBySystem -> True
946 import_info = foldFM mk_imp_info [] mod_map
948 -- Sort exports into groups by module
949 export_fm :: FiniteMap ModuleName [RdrAvailInfo]
950 export_fm = foldr insert emptyFM export_avails
952 insert avail efm = addItem efm (moduleName (nameModule (availName avail)))
955 export_info = [(m, sortExport as) | (m,as) <- fmToList export_fm]
957 returnRn (export_info, import_info)
960 addItem :: FiniteMap ModuleName [a] -> ModuleName -> a -> FiniteMap ModuleName [a]
961 addItem fm mod x = addToFM_C add_item fm mod [x]
965 sortImport :: [(OccName,Version)] -> [(OccName,Version)]
966 -- Make the usage lists appear in canonical order
967 sortImport vs = sortLt lt vs
969 lt (n1,v1) (n2,v2) = n1 < n2
971 sortExport :: [RdrAvailInfo] -> [RdrAvailInfo]
972 sortExport as = sortLt lt as
974 lt a1 a2 = availName a1 < availName a2
979 = getIfacesRn `thenRn` \ ifaces ->
980 returnRn (iSlurp ifaces)
982 recordSlurp ifaces@(Ifaces { iSlurp = slurped_names, iVSlurp = imp_names })
985 new_slurped_names = addAvailToNameSet slurped_names avail
986 new_imp_names = (availName avail, version) : imp_names
988 ifaces { iSlurp = new_slurped_names, iVSlurp = new_imp_names }
990 recordLocalSlurps local_avails
991 = getIfacesRn `thenRn` \ ifaces ->
993 new_slurped_names = foldl addAvailToNameSet (iSlurp ifaces) local_avails
995 setIfacesRn (ifaces { iSlurp = new_slurped_names })
999 %*********************************************************
1001 \subsection{Getting binders out of a declaration}
1003 %*********************************************************
1005 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
1006 It's used for both source code (from @availsFromDecl@) and interface files
1009 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
1010 are handled by the sourc-code specific stuff in @RnNames@.
1013 getDeclBinders :: (RdrName -> SrcLoc -> RnM d Name) -- New-name function
1015 -> RnM d (Maybe AvailInfo)
1017 getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ _ src_loc))
1018 = new_name tycon src_loc `thenRn` \ tycon_name ->
1019 getConFieldNames new_name condecls `thenRn` \ sub_names ->
1020 returnRn (Just (AvailTC tycon_name (tycon_name : nub sub_names)))
1021 -- The "nub" is because getConFieldNames can legitimately return duplicates,
1022 -- when a record declaration has the same field in multiple constructors
1024 getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc))
1025 = new_name tycon src_loc `thenRn` \ tycon_name ->
1026 returnRn (Just (AvailTC tycon_name [tycon_name]))
1028 getDeclBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ _ _ _ _ src_loc))
1029 = new_name cname src_loc `thenRn` \ class_name ->
1031 -- Record the names for the class ops
1033 -- just want class-op sigs
1034 op_sigs = filter isClassOpSig sigs
1036 mapRn (getClassOpNames new_name) op_sigs `thenRn` \ sub_names ->
1038 returnRn (Just (AvailTC class_name (class_name : sub_names)))
1040 getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc))
1041 = new_name var src_loc `thenRn` \ var_name ->
1042 returnRn (Just (Avail var_name))
1044 getDeclBinders new_name (FixD _) = returnRn Nothing
1045 getDeclBinders new_name (DeprecD _) = returnRn Nothing
1047 -- foreign declarations
1048 getDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
1049 | binds_haskell_name kind dyn
1050 = new_name nm loc `thenRn` \ name ->
1051 returnRn (Just (Avail name))
1053 | otherwise -- a foreign export
1054 = lookupImplicitOccRn nm `thenRn_`
1057 getDeclBinders new_name (DefD _) = returnRn Nothing
1058 getDeclBinders new_name (InstD _) = returnRn Nothing
1059 getDeclBinders new_name (RuleD _) = returnRn Nothing
1061 binds_haskell_name (FoImport _) _ = True
1062 binds_haskell_name FoLabel _ = True
1063 binds_haskell_name FoExport ext_nm = isDynamicExtName ext_nm
1066 getConFieldNames new_name (ConDecl con _ _ _ (RecCon fielddecls) src_loc : rest)
1067 = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs ->
1068 getConFieldNames new_name rest `thenRn` \ ns ->
1069 returnRn (cfs ++ ns)
1071 fields = concat (map fst fielddecls)
1073 getConFieldNames new_name (ConDecl con _ _ _ condecl src_loc : rest)
1074 = new_name con src_loc `thenRn` \ n ->
1076 NewCon _ (Just f) ->
1077 new_name f src_loc `thenRn` \ new_f ->
1079 _ -> returnRn [n]) `thenRn` \ nn ->
1080 getConFieldNames new_name rest `thenRn` \ ns ->
1083 getConFieldNames new_name [] = returnRn []
1085 getClassOpNames new_name (ClassOpSig op _ _ _ src_loc) = new_name op src_loc
1088 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
1089 A the moment that's just the tycon and datacon that come with a class decl.
1090 They aren't returned by @getDeclBinders@ because they aren't in scope;
1091 but they {\em should} be put into the @DeclsMap@ of this module.
1093 Note that this excludes the default-method names of a class decl,
1094 and the dict fun of an instance decl, because both of these have
1095 bindings of their own elsewhere.
1098 getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ tname dname dwname snames src_loc))
1099 = sequenceRn [new_name n src_loc | n <- (tname : dname : dwname : snames)]
1101 getDeclSysBinders new_name (TyClD (TyData _ _ _ _ cons _ _ _ _))
1102 = sequenceRn [new_name wkr_name src_loc | ConDecl _ wkr_name _ _ _ src_loc <- cons]
1104 getDeclSysBinders new_name other_decl
1108 %*********************************************************
1110 \subsection{Reading an interface file}
1112 %*********************************************************
1115 findAndReadIface :: SDoc -> ModuleName
1116 -> IsBootInterface -- True <=> Look for a .hi-boot file
1117 -- False <=> Look for .hi file
1118 -> RnM d (Either Message ParsedIface)
1119 -- Nothing <=> file not found, or unreadable, or illegible
1120 -- Just x <=> successfully found and parsed
1122 findAndReadIface doc_str mod_name hi_boot_file
1123 = traceRn trace_msg `thenRn_`
1124 -- we keep two maps for interface files,
1125 -- one for 'normal' ones, the other for .hi-boot files,
1126 -- hence the need to signal which kind we're interested.
1128 getHiMaps `thenRn` \ (search_path, hi_map, hiboot_map) ->
1130 relevant_map | hi_boot_file = hiboot_map
1131 | otherwise = hi_map
1133 case lookupFM relevant_map mod_name of
1135 Just fpath -> traceRn (ptext SLIT("...reading from") <+> text fpath) `thenRn_`
1136 readIface mod_name fpath
1139 Nothing -> traceRn (ptext SLIT("...not found")) `thenRn_`
1140 returnRn (Left (noIfaceErr mod_name hi_boot_file search_path))
1143 trace_msg = sep [hsep [ptext SLIT("Reading"),
1144 if hi_boot_file then ptext SLIT("[boot]") else empty,
1145 ptext SLIT("interface for"),
1146 pprModuleName mod_name <> semi],
1147 nest 4 (ptext SLIT("reason:") <+> doc_str)]
1150 @readIface@ tries just the one file.
1153 readIface :: ModuleName -> String -> RnM d (Either Message ParsedIface)
1154 -- Nothing <=> file not found, or unreadable, or illegible
1155 -- Just x <=> successfully found and parsed
1156 readIface wanted_mod file_path
1157 = ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
1160 case parseIface contents
1161 PState{ bol = 0#, atbol = 1#,
1164 loc = mkSrcLoc (mkFastString file_path) 1 } of
1165 POk _ (PIface iface) ->
1166 warnCheckRn (read_mod == wanted_mod)
1167 (hiModuleNameMismatchWarn wanted_mod read_mod) `thenRn_`
1168 returnRn (Right iface)
1170 read_mod = moduleName (pi_mod iface)
1172 PFailed err -> bale_out err
1173 parse_result -> bale_out empty
1174 -- This last case can happen if the interface file is (say) empty
1175 -- in which case the parser thinks it looks like an IdInfo or
1176 -- something like that. Just an artefact of the fact that the
1177 -- parser is used for several purposes at once.
1179 Left io_err -> bale_out (text (show io_err))
1181 bale_out err = returnRn (Left (badIfaceFile file_path err))
1184 %*********************************************************
1188 %*********************************************************
1191 noIfaceErr mod_name boot_file search_path
1192 = vcat [ptext SLIT("Could not find interface file for") <+> quotes (pprModuleName mod_name),
1193 ptext SLIT("in the directories") <+>
1194 -- \& to avoid cpp interpreting this string as a
1195 -- comment starter with a pre-4.06 mkdependHS --SDM
1196 vcat [ text dir <> text "/\&*" <> pp_suffix suffix
1197 | (dir,suffix) <- search_path]
1200 pp_suffix suffix | boot_file = ptext SLIT(".hi-boot")
1201 | otherwise = text suffix
1203 badIfaceFile file err
1204 = vcat [ptext SLIT("Bad interface file:") <+> text file,
1208 = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
1209 ptext SLIT("from module") <+> quotes (ppr (nameModule name))
1212 getDeclWarn name loc
1213 = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),
1214 ptext SLIT("desired at") <+> ppr loc]
1218 "Compiler tried to import decl from interface file with same name as module."),
1220 "(possible cause: module name clashes with interface file already in scope.)")
1222 hsep [ptext SLIT("name:"), quotes (ppr name)]
1224 warnRedundantSourceImport mod_name
1225 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
1226 <+> quotes (pprModuleName mod_name)
1228 hiModuleNameMismatchWarn :: ModuleName -> ModuleName -> Message
1229 hiModuleNameMismatchWarn requested_mod read_mod =
1230 hsep [ ptext SLIT("Something is amiss; requested module name")
1231 , pprModuleName requested_mod
1232 , ptext SLIT("differs from name found in the interface file")
1233 , pprModuleName read_mod