2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section{Dealing with interface files}
8 readIface, findAndReadIface, loadInterface, loadHomeInterface,
9 tryLoadInterface, loadOrphanModules,
10 loadExports, loadFixDecls, loadDeprecs,
15 removeContext -- removeContext probably belongs somewhere else
18 #include "HsVersions.h"
20 import CmdLineOpts ( DynFlag(..), opt_IgnoreIfacePragmas )
21 import HscTypes ( ModuleLocation(..),
22 ModIface(..), emptyModIface,
25 ImportVersion, WhetherHasOrphans, IsBootInterface,
26 DeclsMap, GatedDecl, IfaceInsts, IfaceRules,
27 AvailInfo, GenAvailInfo(..), Avails, Deprecations(..)
29 import HsSyn ( HsDecl(..), TyClDecl(..), InstDecl(..),
30 HsType(..), ConDecl(..),
31 FixitySig(..), RuleDecl(..),
34 import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl,
37 import BasicTypes ( Version, defaultFixity )
40 import ParseIface ( parseIface, IfaceStuff(..) )
42 import Name ( Name {-instance NamedThing-}, nameOccName,
43 nameModule, isLocalName, nameIsLocalOrFrom,
46 import Name ( mkNameEnv, extendNameEnv )
47 import Module ( Module,
48 moduleName, isModuleInThisPackage,
49 ModuleName, WhereFrom(..),
50 extendModuleEnv, mkVanillaModule
52 import RdrName ( RdrName, rdrNameOcc )
54 import SrcLoc ( mkSrcLoc )
55 import Maybes ( maybeToBool, orElse )
56 import StringBuffer ( hGetStringBuffer )
57 import FastString ( mkFastString )
58 import ErrUtils ( Message )
59 import Finder ( findModule )
60 import Util ( unJust )
70 %*********************************************************
72 \subsection{Loading a new interface file}
74 %*********************************************************
77 loadHomeInterface :: SDoc -> Name -> RnM d ModIface
78 loadHomeInterface doc_str name
79 = ASSERT2( not (isLocalName name), ppr name <+> parens doc_str )
80 loadInterface doc_str (moduleName (nameModule name)) ImportBySystem
82 loadOrphanModules :: [ModuleName] -> RnM d ()
83 loadOrphanModules mods
84 | null mods = returnRn ()
85 | otherwise = traceRn (text "Loading orphan modules:" <+>
86 fsep (map ppr mods)) `thenRn_`
87 mapRn_ load mods `thenRn_`
90 load mod = loadInterface (mk_doc mod) mod ImportBySystem
91 mk_doc mod = ppr mod <+> ptext SLIT("is a orphan-instance module")
93 loadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d ModIface
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 (ModIface, Maybe Message)
101 -- Returns (Just err) if an error happened
102 -- It *doesn't* add an error to the monad, because sometimes it's ok to fail...
103 -- Specifically, when we read the usage information from an interface file,
104 -- we try to read the interfaces it mentions. But it's OK to fail; perhaps
105 -- the module has changed, and that interface is no longer used.
107 -- tryLoadInterface guarantees to return with iImpModInfo m --> (..., True)
108 -- (If the load fails, we plug in a vanilla placeholder)
109 tryLoadInterface doc_str mod_name from
110 = getHomeIfaceTableRn `thenRn` \ hit ->
111 getIfacesRn `thenRn` \ ifaces@(Ifaces { iPIT = pit }) ->
113 -- CHECK WHETHER WE HAVE IT ALREADY
114 case lookupIfaceByModName hit pit mod_name of {
115 Just iface -> returnRn (iface, Nothing) ; -- Already loaded
119 mod_map = iImpModInfo ifaces
120 mod_info = lookupFM mod_map mod_name
123 = case (from, mod_info) of
124 (ImportByUser, _) -> False -- Not hi-boot
125 (ImportByUserSource, _) -> True -- hi-boot
126 (ImportBySystem, Just (_, is_boot)) -> is_boot
127 (ImportBySystem, Nothing) -> False
128 -- We're importing a module we know absolutely
129 -- nothing about, so we assume it's from
130 -- another package, where we aren't doing
131 -- dependency tracking. So it won't be a hi-boot file.
133 redundant_source_import
134 = case (from, mod_info) of
135 (ImportByUserSource, Just (_,False)) -> True
139 -- Issue a warning for a redundant {- SOURCE -} import
140 -- NB that we arrange to read all the ordinary imports before
141 -- any of the {- SOURCE -} imports
142 warnCheckRn (not redundant_source_import)
143 (warnRedundantSourceImport mod_name) `thenRn_`
145 -- READ THE MODULE IN
146 findAndReadIface doc_str mod_name hi_boot_file `thenRn` \ read_result ->
147 case read_result of {
148 Left err -> -- Not found, so add an empty export env to the Ifaces map
149 -- so that we don't look again
151 fake_mod = mkVanillaModule mod_name
152 fake_iface = emptyModIface fake_mod
153 new_ifaces = ifaces { iPIT = extendModuleEnv pit fake_mod fake_iface }
155 setIfacesRn new_ifaces `thenRn_`
156 returnRn (fake_iface, Just err) ;
159 Right (mod, iface) ->
161 -- LOAD IT INTO Ifaces
163 -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
164 --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
165 -- If we do loadExport first the wrong info gets into the cache (unless we
166 -- explicitly tag each export which seems a bit of a bore)
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 } &&
173 isModuleInThisPackage mod,
176 loadDecls mod (iDecls ifaces) (pi_decls iface) `thenRn` \ (decls_vers, new_decls) ->
177 loadRules mod (iRules ifaces) (pi_rules iface) `thenRn` \ (rule_vers, new_rules) ->
178 foldlRn (loadInstDecl mod) (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
179 loadExports (pi_exports iface) `thenRn` \ (export_vers, avails) ->
180 loadFixDecls mod (pi_fixity iface) `thenRn` \ fix_env ->
181 loadDeprecs mod (pi_deprecs iface) `thenRn` \ deprec_env ->
183 version = VersionInfo { vers_module = pi_vers iface,
184 vers_exports = export_vers,
185 vers_rules = rule_vers,
186 vers_decls = decls_vers }
188 -- For an explicit user import, add to mod_map info about
189 -- the things the imported module depends on, extracted
190 -- from its usage info; and delete the module itself, which is now in the PIT
191 mod_map1 = case from of
192 ImportByUser -> addModDeps mod is_loaded (pi_usages iface) mod_map
194 mod_map2 = delFromFM mod_map1 mod_name
195 is_loaded m = maybeToBool (lookupIfaceByModName hit pit m)
197 -- Now add info about this module to the PIT
198 has_orphans = pi_orphan iface
199 new_pit = extendModuleEnv pit mod mod_iface
200 mod_iface = ModIface { mi_module = mod, mi_version = version,
201 mi_orphan = has_orphans, mi_boot = hi_boot_file,
203 mi_fixities = fix_env, mi_deprecs = deprec_env,
204 mi_usages = [], -- Will be filled in later
205 mi_decls = panic "No mi_decls in PIT",
206 mi_globals = panic "No mi_globals in PIT"
209 new_ifaces = ifaces { iPIT = new_pit,
213 iImpModInfo = mod_map2 }
215 setIfacesRn new_ifaces `thenRn_`
216 returnRn (mod_iface, Nothing)
219 -----------------------------------------------------
220 -- Adding module dependencies from the
221 -- import decls in the interface file
222 -----------------------------------------------------
225 -> (ModuleName -> Bool) -- True for module interfaces
227 -> ImportedModuleInfo -> ImportedModuleInfo
228 -- (addModDeps M ivs deps)
229 -- We are importing module M, and M.hi contains 'import' decls given by ivs
230 addModDeps mod is_loaded new_deps mod_deps
231 = foldr add mod_deps filtered_new_deps
233 -- Don't record dependencies when importing a module from another package
234 -- Except for its descendents which contain orphans,
235 -- and in that case, forget about the boot indicator
236 filtered_new_deps :: [(ModuleName, (WhetherHasOrphans, IsBootInterface))]
238 | isModuleInThisPackage mod
239 = [ (imp_mod, (has_orphans, is_boot))
240 | (imp_mod, has_orphans, is_boot, _) <- new_deps,
241 not (is_loaded imp_mod)
243 | otherwise = [ (imp_mod, (True, False))
244 | (imp_mod, has_orphans, _, _) <- new_deps,
245 not (is_loaded imp_mod) && has_orphans
247 add (imp_mod, dep) deps = addToFM_C combine deps imp_mod dep
249 combine old@(old_has_orphans, old_is_boot) new@(new_has_orphans, new_is_boot)
250 | old_is_boot = new -- Record the best is_boot info
253 -----------------------------------------------------
254 -- Loading the export list
255 -----------------------------------------------------
257 loadExports :: (Version, [ExportItem]) -> RnM d (Version, [(ModuleName,Avails)])
258 loadExports (vers, items)
259 = getModuleRn `thenRn` \ this_mod ->
260 mapRn (loadExport this_mod) items `thenRn` \ avails_s ->
261 returnRn (vers, avails_s)
264 loadExport :: Module -> ExportItem -> RnM d (ModuleName, Avails)
265 loadExport this_mod (mod, entities)
266 = mapRn (load_entity mod) entities `thenRn` \ avails ->
267 returnRn (mod, avails)
269 load_entity mod (Avail occ)
270 = newGlobalName mod occ `thenRn` \ name ->
271 returnRn (Avail name)
272 load_entity mod (AvailTC occ occs)
273 = newGlobalName mod occ `thenRn` \ name ->
274 mapRn (newGlobalName mod) occs `thenRn` \ names ->
275 returnRn (AvailTC name names)
278 -----------------------------------------------------
279 -- Loading type/class/value decls
280 -----------------------------------------------------
284 -> [(Version, RdrNameTyClDecl)]
285 -> RnM d (NameEnv Version, DeclsMap)
286 loadDecls mod decls_map decls
287 = foldlRn (loadDecl mod) (emptyNameEnv, decls_map) decls
290 -> (NameEnv Version, DeclsMap)
291 -> (Version, RdrNameTyClDecl)
292 -> RnM d (NameEnv Version, DeclsMap)
293 loadDecl mod (version_map, decls_map) (version, decl)
294 = getIfaceDeclBinders mod decl `thenRn` \ full_avail ->
296 main_name = availName full_avail
297 new_decls_map = extendNameEnvList decls_map stuff
298 stuff = [ (name, (full_avail, name==main_name, (mod, decl)))
299 | name <- availNames full_avail]
301 new_version_map = extendNameEnv version_map main_name version
303 returnRn (new_version_map, new_decls_map)
305 -----------------------------------------------------
306 -- Loading fixity decls
307 -----------------------------------------------------
309 loadFixDecls mod decls
310 = mapRn (loadFixDecl mod_name) decls `thenRn` \ to_add ->
311 returnRn (mkNameEnv to_add)
313 mod_name = moduleName mod
315 loadFixDecl mod_name sig@(FixitySig rdr_name fixity loc)
316 = newGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
317 returnRn (name, fixity)
320 -----------------------------------------------------
321 -- Loading instance decls
322 -----------------------------------------------------
324 loadInstDecl :: Module
328 loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
330 -- Find out what type constructors and classes are "gates" for the
331 -- instance declaration. If all these "gates" are slurped in then
332 -- we should slurp the instance decl too.
334 -- We *don't* want to count names in the context part as gates, though.
336 -- instance Foo a => Baz (T a) where ...
338 -- Here the gates are Baz and T, but *not* Foo.
340 munged_inst_ty = removeContext inst_ty
341 free_names = extractHsTyRdrNames munged_inst_ty
344 mapRn lookupIfaceName free_names `thenRn` \ gate_names ->
345 returnRn ((gate_names, (mod, InstD decl)) `consBag` insts)
348 -- In interface files, the instance decls now look like
349 -- forall a. Foo a -> Baz (T a)
350 -- so we have to strip off function argument types as well
351 -- as the bit before the '=>' (which is always empty in interface files)
352 removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
353 removeContext ty = removeFuns ty
355 removeFuns (HsFunTy _ ty) = removeFuns ty
359 -----------------------------------------------------
361 -----------------------------------------------------
363 loadRules :: Module -> IfaceRules
364 -> (Version, [RdrNameRuleDecl])
365 -> RnM d (Version, IfaceRules)
366 loadRules mod rule_bag (version, rules)
367 | null rules || opt_IgnoreIfacePragmas
368 = returnRn (version, rule_bag)
371 mapRn (loadRule mod) rules `thenRn` \ new_rules ->
372 returnRn (version, rule_bag `unionBags` listToBag new_rules)
374 loadRule :: Module -> RdrNameRuleDecl -> RnM d GatedDecl
375 -- "Gate" the rule simply by whether the rule variable is
376 -- needed. We can refine this later.
377 loadRule mod decl@(IfaceRule _ _ var _ _ src_loc)
378 = lookupIfaceName var `thenRn` \ var_name ->
379 returnRn ([var_name], (mod, RuleD decl))
382 -----------------------------------------------------
383 -- Loading Deprecations
384 -----------------------------------------------------
386 loadDeprecs :: Module -> IfaceDeprecs -> RnM d Deprecations
387 loadDeprecs m Nothing = returnRn NoDeprecs
388 loadDeprecs m (Just (Left txt)) = returnRn (DeprecAll txt)
389 loadDeprecs m (Just (Right prs)) = setModuleRn m $
390 foldlRn loadDeprec emptyNameEnv prs `thenRn` \ env ->
391 returnRn (DeprecSome env)
392 loadDeprec deprec_env (n, txt)
393 = lookupIfaceName n `thenRn` \ name ->
394 traceRn (text "Loaded deprecation(s) for" <+> ppr name <> colon <+> ppr txt) `thenRn_`
395 returnRn (extendNameEnv deprec_env name (name,txt))
399 %*********************************************************
401 \subsection{Getting binders out of a declaration}
403 %*********************************************************
405 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
406 It's used for both source code (from @availsFromDecl@) and interface files
409 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
410 are handled by the sourc-code specific stuff in @RnNames@.
413 getIfaceDeclBinders, getTyClDeclBinders
418 getIfaceDeclBinders mod tycl_decl
419 = getTyClDeclBinders mod tycl_decl `thenRn` \ avail ->
420 getSysTyClDeclBinders mod tycl_decl `thenRn` \ extras ->
421 returnRn (addSysAvails avail extras)
422 -- Add the sys-binders to avail. When we import the decl,
423 -- it's full_avail that will get added to the 'already-slurped' set (iSlurp)
424 -- If we miss out sys-binders, we'll read the decl multiple times!
426 getTyClDeclBinders mod (IfaceSig var ty prags src_loc)
427 = newTopBinder mod var src_loc `thenRn` \ var_name ->
428 returnRn (Avail var_name)
430 getTyClDeclBinders mod tycl_decl
431 = mapRn do_one (tyClDeclNames tycl_decl) `thenRn` \ (main_name:sub_names) ->
432 returnRn (AvailTC main_name (main_name : sub_names))
434 do_one (name,loc) = newTopBinder mod name loc
437 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
438 A the moment that's just the tycon and datacon that come with a class decl.
439 They aren't returned by @getDeclBinders@ because they aren't in scope;
440 but they {\em should} be put into the @DeclsMap@ of this module.
442 Note that this excludes the default-method names of a class decl,
443 and the dict fun of an instance decl, because both of these have
444 bindings of their own elsewhere.
447 getSysTyClDeclBinders mod (ClassDecl _ cname _ _ sigs _ names src_loc)
448 = sequenceRn [newTopBinder mod n src_loc | n <- names]
450 getSysTyClDeclBinders mod (TyData _ _ _ _ cons _ _ _ _ _)
451 = sequenceRn [newTopBinder mod wkr_name src_loc | ConDecl _ wkr_name _ _ _ src_loc <- cons]
453 getSysTyClDeclBinders mod other_decl
457 %*********************************************************
459 \subsection{Reading an interface file}
461 %*********************************************************
464 findAndReadIface :: SDoc -> ModuleName
465 -> IsBootInterface -- True <=> Look for a .hi-boot file
466 -- False <=> Look for .hi file
467 -> RnM d (Either Message (Module, ParsedIface))
468 -- Nothing <=> file not found, or unreadable, or illegible
469 -- Just x <=> successfully found and parsed
471 findAndReadIface doc_str mod_name hi_boot_file
472 = traceRn trace_msg `thenRn_`
473 ioToRnM (findModule mod_name) `thenRn` \ maybe_found ->
474 doptRn Opt_D_dump_rn_trace `thenRn` \ rn_trace ->
476 Right (Just (wanted_mod,locn))
479 (unJust (ml_hi_file locn) "findAndReadIface"
480 ++ if hi_boot_file then "-boot" else "")
482 `thenRn` \ read_result ->
484 Left bad -> returnRn (Left bad)
486 -> let read_mod = pi_mod iface
487 in warnCheckRn (wanted_mod == read_mod)
488 (hiModuleNameMismatchWarn wanted_mod read_mod)
490 returnRn (Right (wanted_mod, iface))
492 other -> traceRn (ptext SLIT("...not found")) `thenRn_`
493 returnRn (Left (noIfaceErr mod_name hi_boot_file))
496 trace_msg = sep [hsep [ptext SLIT("Reading"),
497 if hi_boot_file then ptext SLIT("[boot]") else empty,
498 ptext SLIT("interface for"),
499 ppr mod_name <> semi],
500 nest 4 (ptext SLIT("reason:") <+> doc_str)]
503 @readIface@ tries just the one file.
506 readIface :: Bool -> String -> IO (Either Message ParsedIface)
507 -- Nothing <=> file not found, or unreadable, or illegible
508 -- Just x <=> successfully found and parsed
509 readIface tr file_path
510 = when tr (printErrs (ptext SLIT("readIFace") <+> text file_path))
512 ((hGetStringBuffer False file_path >>= \ contents ->
513 case parseIface contents
514 PState{ bol = 0#, atbol = 1#,
517 loc = mkSrcLoc (mkFastString file_path) 1 } of
518 POk _ (PIface iface) -> return (Right iface)
519 PFailed err -> bale_out err
520 parse_result -> bale_out empty
521 -- This last case can happen if the interface file is (say) empty
522 -- in which case the parser thinks it looks like an IdInfo or
523 -- something like that. Just an artefact of the fact that the
524 -- parser is used for several purposes at once.
527 (\ io_err -> bale_out (text (show io_err))))
529 bale_out err = return (Left (badIfaceFile file_path err))
533 %*********************************************************
535 \subsection{Looking up fixities}
537 %*********************************************************
539 @lookupFixityRn@ has to be in RnIfaces (or RnHiFiles) because
540 it calls @loadHomeInterface@.
542 lookupFixity is a bit strange.
544 * Nested local fixity decls are put in the local fixity env, which we
545 find with getFixtyEnv
547 * Imported fixities are found in the HIT or PIT
549 * Top-level fixity decls in this module may be for Names that are
550 either Global (constructors, class operations)
551 or Local/Exported (everything else)
552 (See notes with RnNames.getLocalDeclBinders for why we have this split.)
553 We put them all in the local fixity environment
556 lookupFixityRn :: Name -> RnMS Fixity
558 = getModuleRn `thenRn` \ this_mod ->
559 if nameIsLocalOrFrom this_mod name
560 then -- It's defined in this module
561 getFixityEnv `thenRn` \ local_fix_env ->
562 returnRn (lookupLocalFixity local_fix_env name)
564 else -- It's imported
565 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
566 -- and consulting the Ifaces that comes back from that, because the interface
567 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
568 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
569 -- right away (after all, it's possible that nothing from B will be used).
570 -- When we come across a use of 'f', we need to know its fixity, and it's then,
571 -- and only then, that we load B.hi. That is what's happening here.
572 loadHomeInterface doc name `thenRn` \ iface ->
573 returnRn (lookupNameEnv (mi_fixities iface) name `orElse` defaultFixity)
575 doc = ptext SLIT("Checking fixity for") <+> ppr name
579 %*********************************************************
583 %*********************************************************
586 noIfaceErr mod_name boot_file
587 = ptext SLIT("Could not find interface file for") <+> quotes (ppr mod_name)
588 -- We used to print the search path, but we can't do that
589 -- now, because it's hidden inside the finder.
590 -- Maybe the finder should expose more functions.
592 badIfaceFile file err
593 = vcat [ptext SLIT("Bad interface file:") <+> text file,
596 hiModuleNameMismatchWarn :: Module -> Module -> Message
597 hiModuleNameMismatchWarn requested_mod read_mod =
598 hsep [ ptext SLIT("Something is amiss; requested module name")
599 , ppr (moduleName requested_mod)
600 , ptext SLIT("differs from name found in the interface file")
604 warnRedundantSourceImport mod_name
605 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
606 <+> quotes (ppr mod_name)