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, isLocallyDefined,
45 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 = 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 ppr mods)) `thenRn_`
86 mapRn_ load mods `thenRn_`
89 load mod = loadInterface (mk_doc mod) mod ImportBySystem
90 mk_doc mod = ppr mod <+> ptext SLIT("is a orphan-instance module")
92 loadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d ModIface
93 loadInterface doc mod from
94 = tryLoadInterface doc mod from `thenRn` \ (ifaces, maybe_err) ->
96 Nothing -> returnRn ifaces
97 Just err -> failWithRn ifaces err
99 tryLoadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d (ModIface, Maybe Message)
100 -- Returns (Just err) if an error happened
101 -- It *doesn't* add an error to the monad, because sometimes it's ok to fail...
102 -- Specifically, when we read the usage information from an interface file,
103 -- we try to read the interfaces it mentions. But it's OK to fail; perhaps
104 -- the module has changed, and that interface is no longer used.
106 -- tryLoadInterface guarantees to return with iImpModInfo m --> (..., True)
107 -- (If the load fails, we plug in a vanilla placeholder)
108 tryLoadInterface doc_str mod_name from
109 = getHomeIfaceTableRn `thenRn` \ hit ->
110 getIfacesRn `thenRn` \ ifaces@(Ifaces { iPIT = pit }) ->
112 -- CHECK WHETHER WE HAVE IT ALREADY
113 case lookupTableByModName hit pit mod_name of {
114 Just iface -> returnRn (iface, Nothing) ; -- Already loaded
118 mod_map = iImpModInfo ifaces
119 mod_info = lookupFM mod_map mod_name
122 = case (from, mod_info) of
123 (ImportByUser, _) -> False -- Not hi-boot
124 (ImportByUserSource, _) -> True -- hi-boot
125 (ImportBySystem, Just (_, is_boot)) -> is_boot
126 (ImportBySystem, Nothing) -> False
127 -- We're importing a module we know absolutely
128 -- nothing about, so we assume it's from
129 -- another package, where we aren't doing
130 -- dependency tracking. So it won't be a hi-boot file.
132 redundant_source_import
133 = case (from, mod_info) of
134 (ImportByUserSource, Just (_,False)) -> True
138 -- Issue a warning for a redundant {- SOURCE -} import
139 -- NB that we arrange to read all the ordinary imports before
140 -- any of the {- SOURCE -} imports
141 warnCheckRn (not redundant_source_import)
142 (warnRedundantSourceImport mod_name) `thenRn_`
144 -- READ THE MODULE IN
145 findAndReadIface doc_str mod_name hi_boot_file `thenRn` \ read_result ->
146 case read_result of {
147 Left err -> -- Not found, so add an empty export env to the Ifaces map
148 -- so that we don't look again
150 fake_mod = mkVanillaModule mod_name
151 fake_iface = emptyModIface fake_mod
152 new_ifaces = ifaces { iPIT = extendModuleEnv pit fake_mod fake_iface }
154 setIfacesRn new_ifaces `thenRn_`
155 returnRn (fake_iface, Just err) ;
158 Right (mod, iface) ->
160 -- LOAD IT INTO Ifaces
162 -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
163 --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
164 -- If we do loadExport first the wrong info gets into the cache (unless we
165 -- explicitly tag each export which seems a bit of a bore)
168 -- Sanity check. If we're system-importing a module we know nothing at all
169 -- about, it should be from a different package to this one
170 WARN( not (maybeToBool mod_info) &&
171 case from of { ImportBySystem -> True; other -> False } &&
172 isModuleInThisPackage mod,
175 loadDecls mod (iDecls ifaces) (pi_decls iface) `thenRn` \ (decls_vers, new_decls) ->
176 loadRules mod (iRules ifaces) (pi_rules iface) `thenRn` \ (rule_vers, new_rules) ->
177 foldlRn (loadInstDecl mod) (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
178 loadExports (pi_exports iface) `thenRn` \ (export_vers, avails) ->
179 loadFixDecls mod (pi_fixity iface) `thenRn` \ fix_env ->
180 loadDeprecs mod (pi_deprecs iface) `thenRn` \ deprec_env ->
182 version = VersionInfo { vers_module = pi_vers iface,
183 vers_exports = export_vers,
184 vers_rules = rule_vers,
185 vers_decls = decls_vers }
187 -- For an explicit user import, add to mod_map info about
188 -- the things the imported module depends on, extracted
189 -- from its usage info; and delete the module itself, which is now in the PIT
190 mod_map1 = case from of
191 ImportByUser -> addModDeps mod is_loaded (pi_usages iface) mod_map
193 mod_map2 = delFromFM mod_map1 mod_name
194 is_loaded m = maybeToBool (lookupTableByModName hit pit m)
196 -- Now add info about this module to the PIT
197 has_orphans = pi_orphan iface
198 new_pit = extendModuleEnv pit mod mod_iface
199 mod_iface = ModIface { mi_module = mod, mi_version = version,
200 mi_orphan = has_orphans, mi_boot = hi_boot_file,
202 mi_fixities = fix_env, mi_deprecs = deprec_env,
203 mi_usages = [], -- Will be filled in later
204 mi_decls = panic "No mi_decls in PIT",
205 mi_globals = panic "No mi_globals in PIT"
208 new_ifaces = ifaces { iPIT = new_pit,
212 iImpModInfo = mod_map2 }
214 setIfacesRn new_ifaces `thenRn_`
215 returnRn (mod_iface, Nothing)
218 -----------------------------------------------------
219 -- Adding module dependencies from the
220 -- import decls in the interface file
221 -----------------------------------------------------
224 -> (ModuleName -> Bool) -- True for module interfaces
226 -> ImportedModuleInfo -> ImportedModuleInfo
227 -- (addModDeps M ivs deps)
228 -- We are importing module M, and M.hi contains 'import' decls given by ivs
229 addModDeps mod is_loaded new_deps mod_deps
230 = foldr add mod_deps filtered_new_deps
232 -- Don't record dependencies when importing a module from another package
233 -- Except for its descendents which contain orphans,
234 -- and in that case, forget about the boot indicator
235 filtered_new_deps :: [(ModuleName, (WhetherHasOrphans, IsBootInterface))]
237 | isModuleInThisPackage mod
238 = [ (imp_mod, (has_orphans, is_boot))
239 | (imp_mod, has_orphans, is_boot, _) <- new_deps,
240 not (is_loaded imp_mod)
242 | otherwise = [ (imp_mod, (True, False))
243 | (imp_mod, has_orphans, _, _) <- new_deps,
244 not (is_loaded imp_mod) && has_orphans
246 add (imp_mod, dep) deps = addToFM_C combine deps imp_mod dep
248 combine old@(old_has_orphans, old_is_boot) new@(new_has_orphans, new_is_boot)
249 | old_is_boot = new -- Record the best is_boot info
252 -----------------------------------------------------
253 -- Loading the export list
254 -----------------------------------------------------
256 loadExports :: (Version, [ExportItem]) -> RnM d (Version, [(ModuleName,Avails)])
257 loadExports (vers, items)
258 = getModuleRn `thenRn` \ this_mod ->
259 mapRn (loadExport this_mod) items `thenRn` \ avails_s ->
260 returnRn (vers, avails_s)
263 loadExport :: Module -> ExportItem -> RnM d (ModuleName, Avails)
264 loadExport this_mod (mod, entities)
265 | mod == moduleName this_mod = returnRn (mod, [])
266 -- If the module exports anything defined in this module, just ignore it.
267 -- Reason: otherwise it looks as if there are two local definition sites
268 -- for the thing, and an error gets reported. Easiest thing is just to
269 -- filter them out up front. This situation only arises if a module
270 -- imports itself, or another module that imported it. (Necessarily,
271 -- this invoves a loop.) Consequence: if you say
276 -- module B( AType ) where
277 -- import {-# SOURCE #-} A( AType )
279 -- then you'll get a 'B does not export AType' message. A bit bogus
280 -- but it's a bogus thing to do!
283 = mapRn (load_entity mod) entities `thenRn` \ avails ->
284 returnRn (mod, avails)
286 load_entity mod (Avail occ)
287 = newGlobalName mod occ `thenRn` \ name ->
288 returnRn (Avail name)
289 load_entity mod (AvailTC occ occs)
290 = newGlobalName mod occ `thenRn` \ name ->
291 mapRn (newGlobalName mod) occs `thenRn` \ names ->
292 returnRn (AvailTC name names)
295 -----------------------------------------------------
296 -- Loading type/class/value decls
297 -----------------------------------------------------
301 -> [(Version, RdrNameTyClDecl)]
302 -> RnM d (NameEnv Version, DeclsMap)
303 loadDecls mod decls_map decls
304 = foldlRn (loadDecl mod) (emptyNameEnv, decls_map) decls
307 -> (NameEnv Version, DeclsMap)
308 -> (Version, RdrNameTyClDecl)
309 -> RnM d (NameEnv Version, DeclsMap)
310 loadDecl mod (version_map, decls_map) (version, decl)
311 = getIfaceDeclBinders mod decl `thenRn` \ full_avail ->
313 main_name = availName full_avail
314 new_decls_map = extendNameEnvList decls_map stuff
315 stuff = [ (name, (full_avail, name==main_name, (mod, decl)))
316 | name <- availNames full_avail]
318 new_version_map = extendNameEnv version_map main_name version
320 returnRn (new_version_map, new_decls_map)
322 -----------------------------------------------------
323 -- Loading fixity decls
324 -----------------------------------------------------
326 loadFixDecls mod decls
327 = mapRn (loadFixDecl mod_name) decls `thenRn` \ to_add ->
328 returnRn (mkNameEnv to_add)
330 mod_name = moduleName mod
332 loadFixDecl mod_name sig@(FixitySig rdr_name fixity loc)
333 = newGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
334 returnRn (name, fixity)
337 -----------------------------------------------------
338 -- Loading instance decls
339 -----------------------------------------------------
341 loadInstDecl :: Module
345 loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
347 -- Find out what type constructors and classes are "gates" for the
348 -- instance declaration. If all these "gates" are slurped in then
349 -- we should slurp the instance decl too.
351 -- We *don't* want to count names in the context part as gates, though.
353 -- instance Foo a => Baz (T a) where ...
355 -- Here the gates are Baz and T, but *not* Foo.
357 munged_inst_ty = removeContext inst_ty
358 free_names = extractHsTyRdrNames munged_inst_ty
361 mapRn lookupOrigName free_names `thenRn` \ gate_names ->
362 returnRn ((mkNameSet gate_names, (mod, InstD decl)) `consBag` insts)
365 -- In interface files, the instance decls now look like
366 -- forall a. Foo a -> Baz (T a)
367 -- so we have to strip off function argument types as well
368 -- as the bit before the '=>' (which is always empty in interface files)
369 removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
370 removeContext ty = removeFuns ty
372 removeFuns (HsFunTy _ ty) = removeFuns ty
376 -----------------------------------------------------
378 -----------------------------------------------------
380 loadRules :: Module -> IfaceRules
381 -> (Version, [RdrNameRuleDecl])
382 -> RnM d (Version, IfaceRules)
383 loadRules mod rule_bag (version, rules)
384 | null rules || opt_IgnoreIfacePragmas
385 = returnRn (version, rule_bag)
388 mapRn (loadRule mod) rules `thenRn` \ new_rules ->
389 returnRn (version, rule_bag `unionBags` listToBag new_rules)
391 loadRule :: Module -> RdrNameRuleDecl -> RnM d GatedDecl
392 -- "Gate" the rule simply by whether the rule variable is
393 -- needed. We can refine this later.
394 loadRule mod decl@(IfaceRule _ _ var _ _ src_loc)
395 = lookupOrigName var `thenRn` \ var_name ->
396 returnRn (unitNameSet var_name, (mod, RuleD decl))
399 -----------------------------------------------------
400 -- Loading Deprecations
401 -----------------------------------------------------
403 loadDeprecs :: Module -> IfaceDeprecs -> RnM d Deprecations
404 loadDeprecs m Nothing = returnRn NoDeprecs
405 loadDeprecs m (Just (Left txt)) = returnRn (DeprecAll txt)
406 loadDeprecs m (Just (Right prs)) = setModuleRn m $
407 foldlRn loadDeprec emptyNameEnv prs `thenRn` \ env ->
408 returnRn (DeprecSome env)
409 loadDeprec deprec_env (n, txt)
410 = lookupOrigName n `thenRn` \ name ->
411 traceRn (text "Loaded deprecation(s) for" <+> ppr name <> colon <+> ppr txt) `thenRn_`
412 returnRn (extendNameEnv deprec_env name (name,txt))
416 %*********************************************************
418 \subsection{Getting binders out of a declaration}
420 %*********************************************************
422 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
423 It's used for both source code (from @availsFromDecl@) and interface files
426 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
427 are handled by the sourc-code specific stuff in @RnNames@.
430 getIfaceDeclBinders, getTyClDeclBinders
435 getIfaceDeclBinders mod tycl_decl
436 = getTyClDeclBinders mod tycl_decl `thenRn` \ avail ->
437 getSysTyClDeclBinders mod tycl_decl `thenRn` \ extras ->
438 returnRn (addSysAvails avail extras)
439 -- Add the sys-binders to avail. When we import the decl,
440 -- it's full_avail that will get added to the 'already-slurped' set (iSlurp)
441 -- If we miss out sys-binders, we'll read the decl multiple times!
443 getTyClDeclBinders mod (IfaceSig var ty prags src_loc)
444 = newTopBinder mod var src_loc `thenRn` \ var_name ->
445 returnRn (Avail var_name)
447 getTyClDeclBinders mod tycl_decl
448 = mapRn do_one (tyClDeclNames tycl_decl) `thenRn` \ (main_name:sub_names) ->
449 returnRn (AvailTC main_name (main_name : sub_names))
451 do_one (name,loc) = newTopBinder mod name loc
454 @getDeclSysBinders@ gets the implicit binders introduced by a decl.
455 A the moment that's just the tycon and datacon that come with a class decl.
456 They aren't returned by @getDeclBinders@ because they aren't in scope;
457 but they {\em should} be put into the @DeclsMap@ of this module.
459 Note that this excludes the default-method names of a class decl,
460 and the dict fun of an instance decl, because both of these have
461 bindings of their own elsewhere.
464 getSysTyClDeclBinders mod (ClassDecl _ cname _ _ sigs _ names src_loc)
465 = sequenceRn [newTopBinder mod n src_loc | n <- names]
467 getSysTyClDeclBinders mod (TyData _ _ _ _ cons _ _ _ _ _)
468 = sequenceRn [newTopBinder mod wkr_name src_loc | ConDecl _ wkr_name _ _ _ src_loc <- cons]
470 getSysTyClDeclBinders mod other_decl
474 %*********************************************************
476 \subsection{Reading an interface file}
478 %*********************************************************
481 findAndReadIface :: SDoc -> ModuleName
482 -> IsBootInterface -- True <=> Look for a .hi-boot file
483 -- False <=> Look for .hi file
484 -> RnM d (Either Message (Module, ParsedIface))
485 -- Nothing <=> file not found, or unreadable, or illegible
486 -- Just x <=> successfully found and parsed
488 findAndReadIface doc_str mod_name hi_boot_file
489 = traceRn trace_msg `thenRn_`
490 ioToRnM (findModule mod_name) `thenRn` \ maybe_found ->
491 doptRn Opt_D_dump_rn_trace `thenRn` \ rn_trace ->
493 Right (Just (wanted_mod,locn))
496 (unJust (ml_hi_file locn) "findAndReadIface"
497 ++ if hi_boot_file then "-boot" else "")
499 `thenRn` \ read_result ->
501 Left bad -> returnRn (Left bad)
503 -> let read_mod = pi_mod iface
504 in warnCheckRn (wanted_mod == read_mod)
505 (hiModuleNameMismatchWarn wanted_mod read_mod)
507 returnRn (Right (wanted_mod, iface))
509 other -> traceRn (ptext SLIT("...not found")) `thenRn_`
510 returnRn (Left (noIfaceErr mod_name hi_boot_file))
513 trace_msg = sep [hsep [ptext SLIT("Reading"),
514 if hi_boot_file then ptext SLIT("[boot]") else empty,
515 ptext SLIT("interface for"),
516 ppr mod_name <> semi],
517 nest 4 (ptext SLIT("reason:") <+> doc_str)]
520 @readIface@ tries just the one file.
523 readIface :: Bool -> String -> IO (Either Message ParsedIface)
524 -- Nothing <=> file not found, or unreadable, or illegible
525 -- Just x <=> successfully found and parsed
526 readIface tr file_path
527 = when tr (printErrs (ptext SLIT("readIFace") <+> text file_path))
529 ((hGetStringBuffer False file_path >>= \ contents ->
530 case parseIface contents
531 PState{ bol = 0#, atbol = 1#,
534 loc = mkSrcLoc (mkFastString file_path) 1 } of
535 POk _ (PIface iface) -> return (Right iface)
536 PFailed err -> bale_out err
537 parse_result -> bale_out empty
538 -- This last case can happen if the interface file is (say) empty
539 -- in which case the parser thinks it looks like an IdInfo or
540 -- something like that. Just an artefact of the fact that the
541 -- parser is used for several purposes at once.
544 (\ io_err -> bale_out (text (show io_err))))
546 bale_out err = return (Left (badIfaceFile file_path err))
550 %*********************************************************
552 \subsection{Looking up fixities}
554 %*********************************************************
556 This has to be in RnIfaces (or RnHiFiles) because it calls loadHomeInterface
559 lookupFixityRn :: Name -> RnMS Fixity
561 | isLocallyDefined name
562 = getFixityEnv `thenRn` \ local_fix_env ->
563 returnRn (lookupLocalFixity local_fix_env name)
565 | otherwise -- Imported
566 -- For imported names, we have to get their fixities by doing a loadHomeInterface,
567 -- and consulting the Ifaces that comes back from that, because the interface
568 -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
569 -- which exports a function 'f', which is defined in module B. Then B isn't loaded
570 -- right away (after all, it's possible that nothing from B will be used).
571 -- When we come across a use of 'f', we need to know its fixity, and it's then,
572 -- and only then, that we load B.hi. That is what's happening here.
573 = getHomeIfaceTableRn `thenRn` \ hit ->
574 loadHomeInterface doc name `thenRn` \ iface ->
575 returnRn (lookupNameEnv (mi_fixities iface) name `orElse` defaultFixity)
577 doc = ptext SLIT("Checking fixity for") <+> ppr name
581 %*********************************************************
585 %*********************************************************
588 noIfaceErr mod_name boot_file
589 = ptext SLIT("Could not find interface file for") <+> quotes (ppr mod_name)
590 -- We used to print the search path, but we can't do that
591 -- now, because it's hidden inside the finder.
592 -- Maybe the finder should expose more functions.
594 badIfaceFile file err
595 = vcat [ptext SLIT("Bad interface file:") <+> text file,
598 hiModuleNameMismatchWarn :: Module -> Module -> Message
599 hiModuleNameMismatchWarn requested_mod read_mod =
600 hsep [ ptext SLIT("Something is amiss; requested module name")
601 , ppr (moduleName requested_mod)
602 , ptext SLIT("differs from name found in the interface file")
606 warnRedundantSourceImport mod_name
607 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
608 <+> quotes (ppr mod_name)