2 % (c) The GRASP Project, Glasgow University, 1992-1998
4 \section[Rename]{Renaming and dependency analysis passes}
7 module Rename ( renameModule ) where
9 #include "HsVersions.h"
12 import RdrHsSyn ( RdrName(..), RdrNameHsModule )
13 import RnHsSyn ( RenamedHsModule, RenamedHsDecl, extractHsTyNames )
15 import CmdLineOpts ( opt_HiMap, opt_D_show_rn_trace,
16 opt_D_dump_rn, opt_D_show_rn_stats,
17 opt_WarnUnusedBinds, opt_WarnUnusedImports
20 import RnNames ( getGlobalNames )
21 import RnSource ( rnIfaceDecl, rnSourceDecls )
22 import RnIfaces ( getImportedInstDecls, importDecl, getImportVersions, getSpecialInstModules,
24 mkSearchPath, getSlurpedNames, getRnStats
26 import RnEnv ( addImplicitOccsRn, availName, availNames, availsToNameSet, warnUnusedTopNames )
27 import Name ( Name, isLocallyDefined,
28 NamedThing(..), ImportReason(..), Provenance(..),
29 nameModule, pprModule, pprOccName, nameOccName,
33 import TyCon ( TyCon )
34 import PrelMods ( mAIN, pREL_MAIN )
35 import TysWiredIn ( unitTyCon, intTyCon, doubleTyCon )
36 import PrelInfo ( ioTyCon_NAME, thinAirIdNames )
37 import ErrUtils ( pprBagOfErrors, pprBagOfWarnings,
38 doIfSet, dumpIfSet, ghcExit
40 import Bag ( isEmptyBag )
41 import FiniteMap ( fmToList, delListFromFM )
42 import UniqSupply ( UniqSupply )
43 import Util ( equivClasses )
44 import Maybes ( maybeToBool )
51 renameModule :: UniqSupply
54 ( RenamedHsModule -- Output, after renaming
55 , InterfaceDetails -- Interface; for interface file generatino
56 , RnNameSupply -- Final env; for renaming derivings
57 , [Module] -- Imported modules; for profiling
60 renameModule us this_mod@(HsModule mod_name vers exports imports local_decls loc)
61 = -- Initialise the renamer monad
62 initRn mod_name us (mkSearchPath opt_HiMap) loc
64 \ (maybe_rn_stuff, rn_errs_bag, rn_warns_bag) ->
67 doIfSet (not (isEmptyBag rn_warns_bag))
68 (printErrs (pprBagOfWarnings rn_warns_bag)) >>
70 -- Check for errors; exit if so
71 doIfSet (not (isEmptyBag rn_errs_bag))
72 (printErrs (pprBagOfErrors rn_errs_bag) >>
76 -- Dump output, if any
77 (case maybe_rn_stuff of
79 Just results@(rn_mod, _, _, _)
80 -> dumpIfSet opt_D_dump_rn "Renamer:"
90 rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
91 = -- FIND THE GLOBAL NAME ENVIRONMENT
92 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
94 -- CHECK FOR EARLY EXIT
95 if not (maybeToBool maybe_stuff) then
96 -- Everything is up to date; no need to recompile further
101 Just (export_env, rn_env, global_avail_env) = maybe_stuff
105 initRnMS rn_env mod_name SourceMode (
106 addImplicits mod_name `thenRn_`
107 rnSourceDecls local_decls
108 ) `thenRn` \ (rn_local_decls, fvs) ->
110 -- SLURP IN ALL THE NEEDED DECLARATIONS
111 slurpDecls rn_local_decls `thenRn` \ rn_all_decls ->
113 -- EXIT IF ERRORS FOUND
114 checkErrsRn `thenRn` \ no_errs_so_far ->
115 if not no_errs_so_far then
116 -- Found errors already, so exit now
121 -- GENERATE THE VERSION/USAGE INFO
122 getImportVersions mod_name exports `thenRn` \ import_versions ->
123 getNameSupplyRn `thenRn` \ name_supply ->
125 -- REPORT UNUSED NAMES
126 reportUnusedNames rn_env global_avail_env
130 -- GENERATE THE SPECIAL-INSTANCE MODULE LIST
131 -- The "special instance" modules are those modules that contain instance
132 -- declarations that contain no type constructor or class that was declared
134 getSpecialInstModules `thenRn` \ imported_special_inst_mods ->
136 special_inst_decls = [d | InstD d@(InstDecl inst_ty _ _ _ _) <- rn_local_decls,
137 all (not.isLocallyDefined) (nameSetToList (extractHsTyNames inst_ty))
139 special_inst_mods | null special_inst_decls = imported_special_inst_mods
140 | otherwise = mod_name : imported_special_inst_mods
144 -- RETURN THE RENAMED MODULE
146 import_mods = [mod | ImportDecl mod _ _ _ _ _ <- imports]
148 renamed_module = HsModule mod_name vers
149 trashed_exports trashed_imports
153 rnStats rn_all_decls `thenRn_`
154 returnRn (Just (renamed_module,
155 (import_versions, export_env, special_inst_mods),
159 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
160 trashed_imports = {-trace "rnSource:trashed_imports"-} []
163 @addImplicits@ forces the renamer to slurp in some things which aren't
164 mentioned explicitly, but which might be needed by the type checker.
167 addImplicits mod_name
168 = addImplicitOccsRn (implicit_main ++ default_tys ++ thinAirIdNames)
170 -- Add occurrences for Int, Double, and (), because they
171 -- are the types to which ambigious type variables may be defaulted by
172 -- the type checker; so they won't always appear explicitly.
173 -- [The () one is a GHC extension for defaulting CCall results.]
174 default_tys = [getName intTyCon, getName doubleTyCon, getName unitTyCon ]
176 -- Add occurrences for IO or PrimIO
177 implicit_main | mod_name == mAIN
178 || mod_name == pREL_MAIN = [ioTyCon_NAME]
185 = -- First of all, get all the compulsory decls
186 slurp_compulsories decls `thenRn` \ decls1 ->
188 -- Next get the optional ones
189 closeDecls optional_mode decls1 `thenRn` \ decls2 ->
191 -- Finally get those deferred data type declarations
192 getDeferredDataDecls `thenRn` \ data_decls ->
193 mapRn (rn_data_decl compulsory_mode) data_decls `thenRn` \ rn_data_decls ->
196 returnRn (rn_data_decls ++ decls2)
199 compulsory_mode = InterfaceMode Compulsory
200 optional_mode = InterfaceMode Optional
202 -- The "slurp_compulsories" function is a loop that alternates
203 -- between slurping compulsory decls and slurping the instance
204 -- decls thus made relavant.
205 -- We *must* loop again here. Why? Two reasons:
206 -- (a) an instance decl will give rise to an unresolved dfun, whose
207 -- decl we must slurp to get its version number; that's the version
208 -- number for the whole instance decl. (And its unfolding might mention new
209 -- unresolved names.)
210 -- (b) an instance decl might give rise to a new unresolved class,
211 -- whose decl we must slurp, which might let in some new instance decls,
212 -- and so on. Example: instance Foo a => Baz [a] where ...
213 slurp_compulsories decls
214 = closeDecls compulsory_mode decls `thenRn` \ decls1 ->
216 -- Instance decls still pending?
217 getImportedInstDecls `thenRn` \ inst_decls ->
218 if null inst_decls then
222 -- Yes, there are some, so rename them and loop
223 traceRn (sep [ptext SLIT("Slurped"), int (length inst_decls), ptext SLIT("instance decls")])
225 mapRn (rn_inst_decl compulsory_mode) inst_decls `thenRn` \ new_inst_decls ->
226 slurp_compulsories (new_inst_decls ++ decls1)
230 closeDecls :: RnSMode
231 -> [RenamedHsDecl] -- Declarations got so far
232 -> RnMG [RenamedHsDecl] -- input + extra decls slurped
233 -- The monad includes a list of possibly-unresolved Names
234 -- This list is empty when closeDecls returns
236 closeDecls mode decls
237 = popOccurrenceName mode `thenRn` \ maybe_unresolved ->
238 case maybe_unresolved of
240 -- No more unresolved names
241 Nothing -> returnRn decls
243 -- An unresolved name
245 -> -- Slurp its declaration, if any
246 -- traceRn (sep [ptext SLIT("Considering"), ppr name_w_loc]) `thenRn_`
247 importDecl name_w_loc mode `thenRn` \ maybe_decl ->
250 -- No declaration... (wired in thing or optional)
251 Nothing -> closeDecls mode decls
253 -- Found a declaration... rename it
254 Just decl -> rn_iface_decl mod_name mode decl `thenRn` \ new_decl ->
255 closeDecls mode (new_decl : decls)
257 mod_name = nameModule (fst name_w_loc)
259 rn_iface_decl mod_name mode decl
260 = initRnMS emptyRnEnv mod_name mode (rnIfaceDecl decl)
262 rn_inst_decl mode (mod_name,decl) = rn_iface_decl mod_name mode (InstD decl)
263 rn_data_decl mode (mod_name,ty_decl) = rn_iface_decl mod_name mode (TyClD ty_decl)
267 reportUnusedNames (RnEnv gbl_env _) avail_env (ExportEnv export_avails _) mentioned_names
268 | not (opt_WarnUnusedBinds || opt_WarnUnusedImports)
273 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
275 -- Now, a use of C implies a use of T,
276 -- if C was brought into scope by T(..) or T(C)
277 really_used_names = used_names `unionNameSets`
278 mkNameSet [ availName avail
279 | sub_name <- nameSetToList used_names,
280 let avail = case lookupNameEnv avail_env sub_name of
282 Nothing -> pprTrace "r.u.n" (ppr sub_name) $
286 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
287 defined_but_not_used = defined_names `minusNameSet` really_used_names
289 -- Filter out the ones only defined implicitly
290 bad_guys = filter is_explicit (nameSetToList defined_but_not_used)
291 is_explicit n = case getNameProvenance n of
293 NonLocalDef (UserImport _ _ explicit) _ _ -> explicit
296 -- Now group by whether locally defined or imported;
297 -- one group is the locally-defined ones, one group per import module
298 groups = equivClasses cmp bad_guys
300 name1 `cmp` name2 = getNameProvenance name1 `cmph` getNameProvenance name2
302 cmph (LocalDef _ _) (NonLocalDef _ _ _) = LT
303 cmph (LocalDef _ _) (LocalDef _ _) = EQ
304 cmph (NonLocalDef (UserImport m1 _ _) _ _)
305 (NonLocalDef (UserImport m2 _ _) _ _)
307 cmph (NonLocalDef _ _ _) (LocalDef _ _) = GT
308 -- In-scope NonLocalDefs must have UserImport info on them
310 -- ToDo: report somehow on T(..) things where no constructors
313 mapRn warnUnusedTopNames groups `thenRn_`
316 rnStats :: [RenamedHsDecl] -> RnMG ()
318 | opt_D_show_rn_trace ||
319 opt_D_show_rn_stats ||
321 = getRnStats all_decls `thenRn` \ msg ->
322 ioToRnMG (printErrs msg) `thenRn_`
325 | otherwise = returnRn ()