%
-% (c) The GRASP Project, Glasgow University, 1992-1996
+% (c) The GRASP Project, Glasgow University, 1992-1998
%
\section[Rename]{Renaming and dependency analysis passes}
\begin{code}
-#include "HsVersions.h"
-
module Rename ( renameModule ) where
-import PreludeGlaST ( thenPrimIO )
-
-IMP_Ubiq()
-IMPORT_1_3(List(partition))
+#include "HsVersions.h"
import HsSyn
-import RdrHsSyn ( RdrName, SYN_IE(RdrNameHsModule), SYN_IE(RdrNameImportDecl) )
-import RnHsSyn ( SYN_IE(RenamedHsModule), SYN_IE(RenamedHsDecl), extractHsTyNames )
+import RdrHsSyn ( RdrNameHsModule )
+import RnHsSyn ( RenamedHsModule, RenamedHsDecl, extractHsTyNames )
-import CmdLineOpts ( opt_HiMap )
+import CmdLineOpts ( opt_HiMap, opt_D_show_rn_trace,
+ opt_D_dump_rn, opt_D_show_rn_stats,
+ opt_WarnUnusedBinds, opt_WarnUnusedImports
+ )
import RnMonad
import RnNames ( getGlobalNames )
-import RnSource ( rnDecl )
-import RnIfaces ( getImportedInstDecls, getDecl, getImportVersions, getSpecialInstModules,
- mkSearchPath, getWiredInDecl
+import RnSource ( rnIfaceDecl, rnSourceDecls )
+import RnIfaces ( getImportedInstDecls, importDecl, getImportVersions, getSpecialInstModules,
+ getDeferredDataDecls,
+ mkSearchPath, getSlurpedNames, getRnStats
)
-import RnEnv ( availsToNameSet, addAvailToNameSet, addImplicitOccsRn )
-import Id ( GenId {- instance NamedThing -} )
-import Name ( Name, Provenance, ExportFlag(..), isLocallyDefined,
- NameSet(..), elemNameSet, mkNameSet, unionNameSets, nameSetToList,
- isWiredInName, modAndOcc
+import RnEnv ( addImplicitOccsRn, availName, availNames, availsToNameSet,
+ warnUnusedTopNames
)
-import TysWiredIn ( unitTyCon, intTyCon, doubleTyCon )
+import Module ( pprModule )
+import Name ( Name, isLocallyDefined,
+ NamedThing(..), ImportReason(..), Provenance(..),
+ nameModule, pprOccName, nameOccName,
+ getNameProvenance, occNameUserString,
+ )
+import RdrName ( RdrName )
+import NameSet
import TyCon ( TyCon )
-import ErrUtils ( SYN_IE(Error), SYN_IE(Warning) )
-import FiniteMap ( emptyFM, eltsFM, fmToList, addToFM, FiniteMap )
-import Pretty
-import PprStyle ( PprStyle(..) )
-import Util ( panic, assertPanic, pprTrace )
+import PrelMods ( mAIN, pREL_MAIN )
+import TysWiredIn ( unitTyCon, intTyCon, doubleTyCon )
+import PrelInfo ( ioTyCon_NAME, thinAirIdNames )
+import Type ( funTyCon )
+import ErrUtils ( pprBagOfErrors, pprBagOfWarnings,
+ doIfSet, dumpIfSet, ghcExit
+ )
+import Bag ( isEmptyBag )
+import FiniteMap ( fmToList, delListFromFM )
+import UniqSupply ( UniqSupply )
+import Util ( equivClasses )
+import Maybes ( maybeToBool )
+import Outputable
\end{code}
\begin{code}
renameModule :: UniqSupply
-> RdrNameHsModule
- -> IO (Maybe -- Nothing <=> everything up to date;
- -- no ned to recompile any further
- (RenamedHsModule, -- Output, after renaming
- InterfaceDetails, -- Interface; for interface file generatino
- RnNameSupply, -- Final env; for renaming derivings
- [Module]), -- Imported modules; for profiling
- Bag Error,
- Bag Warning
- )
-\end{code}
+ -> IO (Maybe
+ ( RenamedHsModule -- Output, after renaming
+ , InterfaceDetails -- Interface; for interface file generatino
+ , RnNameSupply -- Final env; for renaming derivings
+ , [Module] -- Imported modules; for profiling
+ ))
+
+renameModule us this_mod@(HsModule mod_name vers exports imports local_decls loc)
+ = -- Initialise the renamer monad
+ initRn mod_name us (mkSearchPath opt_HiMap) loc
+ (rename this_mod) >>=
+ \ (maybe_rn_stuff, rn_errs_bag, rn_warns_bag) ->
+
+ -- Check for warnings
+ doIfSet (not (isEmptyBag rn_warns_bag))
+ (printErrs (pprBagOfWarnings rn_warns_bag)) >>
+
+ -- Check for errors; exit if so
+ doIfSet (not (isEmptyBag rn_errs_bag))
+ (printErrs (pprBagOfErrors rn_errs_bag) >>
+ ghcExit 1
+ ) >>
+
+ -- Dump output, if any
+ (case maybe_rn_stuff of
+ Nothing -> return ()
+ Just results@(rn_mod, _, _, _)
+ -> dumpIfSet opt_D_dump_rn "Renamer:"
+ (ppr rn_mod)
+ ) >>
+
+ -- Return results
+ return maybe_rn_stuff
+\end{code}
\begin{code}
-renameModule us this_mod@(HsModule mod_name vers exports imports fixities local_decls loc)
- = -- INITIALISE THE RENAMER MONAD
- initRn mod_name us (mkSearchPath opt_HiMap) loc $
-
- -- FIND THE GLOBAL NAME ENVIRONMENT
- getGlobalNames this_mod `thenRn` \ global_name_info ->
-
- case global_name_info of {
- Nothing -> -- Everything is up to date; no need to recompile further
- returnRn Nothing ;
-
- -- Otherwise, just carry on
- Just (export_env, rn_env, local_avails) ->
+rename this_mod@(HsModule mod_name vers exports imports local_decls loc)
+ = -- FIND THE GLOBAL NAME ENVIRONMENT
+ getGlobalNames this_mod `thenRn` \ maybe_stuff ->
+
+ -- CHECK FOR EARLY EXIT
+ if not (maybeToBool maybe_stuff) then
+ -- Everything is up to date; no need to recompile further
+ rnStats [] `thenRn_`
+ returnRn Nothing
+ else
+ let
+ Just (export_env, rn_env, global_avail_env) = maybe_stuff
+ in
-- RENAME THE SOURCE
- -- We also add occurrences for Int, Double, and (), because they
- -- are the types to which ambigious type variables may be defaulted by
- -- the type checker; so they won't every appear explicitly.
- -- [The () one is a GHC extension for defaulting CCall results.]
- initRnMS rn_env mod_name SourceMode (mapRn rnDecl local_decls) `thenRn` \ rn_local_decls ->
- addImplicitOccsRn [getName intTyCon,
- getName doubleTyCon,
- getName unitTyCon] `thenRn_`
+ initRnMS rn_env SourceMode (
+ addImplicits mod_name `thenRn_`
+ rnSourceDecls local_decls
+ ) `thenRn` \ (rn_local_decls, fvs) ->
-- SLURP IN ALL THE NEEDED DECLARATIONS
- -- Notice that the rnEnv starts empty
- closeDecls rn_local_decls (availsToNameSet local_avails) []
- `thenRn` \ (rn_all_decls, imported_avails) ->
-
- -- SLURP IN ALL NEEDED INSTANCE DECLARATIONS
- -- We keep the ones that only mention things (type constructors, classes) that are
- -- already imported. Ones which don't can't possibly be useful to us.
- getImportedInstDecls `thenRn` \ imported_insts ->
- let
- all_big_names = mkNameSet [name | Avail name _ <- local_avails] `unionNameSets`
- mkNameSet [name | Avail name _ <- imported_avails]
-
- rn_needed_insts = [ initRnMS emptyRnEnv mod_name InterfaceMode (rnDecl (InstD inst_decl))
- | (inst_names, mod_name, inst_decl) <- imported_insts,
- all (`elemNameSet` all_big_names) inst_names
- ]
- in
- sequenceRn rn_needed_insts `thenRn` \ inst_decls ->
- -- Maybe we need to do another close-decls?
+ slurpDecls rn_local_decls `thenRn` \ rn_all_decls ->
+ -- EXIT IF ERRORS FOUND
+ checkErrsRn `thenRn` \ no_errs_so_far ->
+ if not no_errs_so_far then
+ -- Found errors already, so exit now
+ rnStats [] `thenRn_`
+ returnRn Nothing
+ else
-- GENERATE THE VERSION/USAGE INFO
- getImportVersions imported_avails `thenRn` \ import_versions ->
+ getImportVersions mod_name exports `thenRn` \ import_versions ->
getNameSupplyRn `thenRn` \ name_supply ->
+ -- REPORT UNUSED NAMES
+ reportUnusedNames rn_env global_avail_env
+ export_env
+ fvs `thenRn_`
-- GENERATE THE SPECIAL-INSTANCE MODULE LIST
-- The "special instance" modules are those modules that contain instance
in
-
-- RETURN THE RENAMED MODULE
let
import_mods = [mod | ImportDecl mod _ _ _ _ <- imports]
renamed_module = HsModule mod_name vers
- trashed_exports trashed_imports trashed_fixities
- (inst_decls ++ rn_all_decls)
+ trashed_exports trashed_imports
+ rn_all_decls
loc
in
+ rnStats rn_all_decls `thenRn_`
returnRn (Just (renamed_module,
(import_versions, export_env, special_inst_mods),
name_supply,
import_mods))
- }
where
trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
trashed_imports = {-trace "rnSource:trashed_imports"-} []
- trashed_fixities = []
\end{code}
+@addImplicits@ forces the renamer to slurp in some things which aren't
+mentioned explicitly, but which might be needed by the type checker.
+
\begin{code}
-closeDecls :: [RenamedHsDecl] -- Declarations got so far
- -> NameSet -- Names bound by those declarations
- -> [AvailInfo] -- Available stuff generated by closeDecls so far
- -> RnMG ([RenamedHsDecl], -- The closed set
- [AvailInfo]) -- Available stuff generated by closeDecls
- -- The monad includes a list of possibly-unresolved Names
- -- This list is empty when closeDecls returns
+addImplicits mod_name
+ = addImplicitOccsRn (implicit_main ++ default_tys ++ thinAirIdNames)
+ where
+ -- Add occurrences for Int, Double, and (), because they
+ -- are the types to which ambigious type variables may be defaulted by
+ -- the type checker; so they won't always appear explicitly.
+ -- [The () one is a GHC extension for defaulting CCall results.]
+ -- ALSO: funTyCon, since it occurs implicitly everywhere!
+ -- (we don't want to be bothered with addImplicitOcc at every
+ -- function application)
+ default_tys = [getName intTyCon, getName doubleTyCon,
+ getName unitTyCon, getName funTyCon]
+
+ -- Add occurrences for IO or PrimIO
+ implicit_main | mod_name == mAIN
+ || mod_name == pREL_MAIN = [ioTyCon_NAME]
+ | otherwise = []
+\end{code}
-closeDecls decls decl_names import_avails
- = popOccurrenceName `thenRn` \ maybe_unresolved ->
- case maybe_unresolved of
+\begin{code}
+slurpDecls decls
+ = -- First of all, get all the compulsory decls
+ slurp_compulsories decls `thenRn` \ decls1 ->
- -- No more unresolved names; we're done
- Nothing -> returnRn (decls, import_avails)
+ -- Next get the optional ones
+ closeDecls optional_mode decls1 `thenRn` \ decls2 ->
- -- An "unresolved" name that we've already dealt with
- Just (name,_) | name `elemNameSet` decl_names
- -> closeDecls decls decl_names import_avails
+ -- Finally get those deferred data type declarations
+ getDeferredDataDecls `thenRn` \ data_decls ->
+ mapRn (rn_data_decl compulsory_mode) data_decls `thenRn` \ rn_data_decls ->
+
+ -- Done
+ returnRn (rn_data_decls ++ decls2)
+
+ where
+ compulsory_mode = InterfaceMode Compulsory
+ optional_mode = InterfaceMode Optional
+
+ -- The "slurp_compulsories" function is a loop that alternates
+ -- between slurping compulsory decls and slurping the instance
+ -- decls thus made relavant.
+ -- We *must* loop again here. Why? Two reasons:
+ -- (a) an instance decl will give rise to an unresolved dfun, whose
+ -- decl we must slurp to get its version number; that's the version
+ -- number for the whole instance decl. (And its unfolding might mention new
+ -- unresolved names.)
+ -- (b) an instance decl might give rise to a new unresolved class,
+ -- whose decl we must slurp, which might let in some new instance decls,
+ -- and so on. Example: instance Foo a => Baz [a] where ...
+ slurp_compulsories decls
+ = closeDecls compulsory_mode decls `thenRn` \ decls1 ->
- -- An unresolved name that's wired in. In this case there's no
- -- declaration to get, but we still want to record it as now available,
- -- so that we remember to look for instance declarations involving it.
- Just (name,_) | isWiredInName name
- -> getWiredInDecl name `thenRn` \ decl_avail ->
- closeDecls decls
- (addAvailToNameSet decl_names decl_avail)
- (decl_avail : import_avails)
-
- -- Genuinely unresolved name
- Just (name,necessity) | otherwise
- -> getDecl name `thenRn` \ (decl_avail,new_decl) ->
- case decl_avail of
-
- -- Can't find the declaration; check that it was optional
- NotAvailable -> checkRn (case necessity of { Optional -> True; other -> False})
- (getDeclErr name) `thenRn_`
- closeDecls decls decl_names import_avails
-
- -- Found it
- other -> initRnMS emptyRnEnv mod_name InterfaceMode (
- rnDecl new_decl
- ) `thenRn` \ rn_decl ->
- closeDecls (rn_decl : decls)
- (addAvailToNameSet decl_names decl_avail)
- (decl_avail : import_avails)
- where
- (mod_name,_) = modAndOcc name
-
-getDeclErr name sty
- = ppSep [ppStr "Failed to find interface decl for", ppr sty name]
+ -- Instance decls still pending?
+ getImportedInstDecls `thenRn` \ inst_decls ->
+ if null inst_decls then
+ -- No, none
+ returnRn decls1
+ else
+ -- Yes, there are some, so rename them and loop
+ traceRn (sep [ptext SLIT("Slurped"), int (length inst_decls), ptext SLIT("instance decls")])
+ `thenRn_`
+ mapRn (rn_inst_decl compulsory_mode) inst_decls `thenRn` \ new_inst_decls ->
+ slurp_compulsories (new_inst_decls ++ decls1)
+\end{code}
+
+\begin{code}
+closeDecls :: RnMode
+ -> [RenamedHsDecl] -- Declarations got so far
+ -> RnMG [RenamedHsDecl] -- input + extra decls slurped
+ -- The monad includes a list of possibly-unresolved Names
+ -- This list is empty when closeDecls returns
+
+closeDecls mode decls
+ = popOccurrenceName mode `thenRn` \ maybe_unresolved ->
+ case maybe_unresolved of
+
+ -- No more unresolved names
+ Nothing -> returnRn decls
+
+ -- An unresolved name
+ Just name_w_loc
+ -> -- Slurp its declaration, if any
+-- traceRn (sep [ptext SLIT("Considering"), ppr name_w_loc]) `thenRn_`
+ importDecl name_w_loc mode `thenRn` \ maybe_decl ->
+ case maybe_decl of
+
+ -- No declaration... (wired in thing or optional)
+ Nothing -> closeDecls mode decls
+
+ -- Found a declaration... rename it
+ Just decl -> rn_iface_decl mod_name mode decl `thenRn` \ new_decl ->
+ closeDecls mode (new_decl : decls)
+ where
+ mod_name = nameModule (fst name_w_loc)
+
+rn_iface_decl mod_name mode decl
+ = setModuleRn mod_name $
+ initRnMS emptyRnEnv mode (rnIfaceDecl decl)
+
+rn_inst_decl mode (mod_name,decl) = rn_iface_decl mod_name mode (InstD decl)
+rn_data_decl mode (mod_name,ty_decl) = rn_iface_decl mod_name mode (TyClD ty_decl)
\end{code}
+\begin{code}
+reportUnusedNames (RnEnv gbl_env _) avail_env (ExportEnv export_avails _) mentioned_names
+ | not (opt_WarnUnusedBinds || opt_WarnUnusedImports)
+ = returnRn ()
+
+ | otherwise
+ = let
+ used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
+
+ -- Now, a use of C implies a use of T,
+ -- if C was brought into scope by T(..) or T(C)
+ really_used_names = used_names `unionNameSets`
+ mkNameSet [ availName avail
+ | sub_name <- nameSetToList used_names,
+ let avail = case lookupNameEnv avail_env sub_name of
+ Just avail -> avail
+ Nothing -> pprTrace "r.u.n" (ppr sub_name) $
+ Avail sub_name
+ ]
+
+ defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
+ defined_but_not_used = nameSetToList (defined_names `minusNameSet` really_used_names)
+
+ -- Filter out the ones only defined implicitly
+ bad_guys = filter reportableUnusedName defined_but_not_used
+ in
+ warnUnusedTopNames bad_guys `thenRn_`
+ returnRn ()
+
+reportableUnusedName :: Name -> Bool
+reportableUnusedName name
+ = explicitlyImported (getNameProvenance name) &&
+ not (startsWithUnderscore (occNameUserString (nameOccName name)))
+ where
+ explicitlyImported (LocalDef _ _) = True -- Report unused defns of local vars
+ explicitlyImported (NonLocalDef (UserImport _ _ expl) _) = expl -- Report unused explicit imports
+ explicitlyImported other = False -- Don't report others
+
+ -- Haskell 98 encourages compilers to suppress warnings about
+ -- unused names in a pattern if they start with "_".
+ startsWithUnderscore ('_' : _) = True -- Suppress warnings for names starting
+ startsWithUnderscore other = False -- with an underscore
+
+rnStats :: [RenamedHsDecl] -> RnMG ()
+rnStats all_decls
+ | opt_D_show_rn_trace ||
+ opt_D_show_rn_stats ||
+ opt_D_dump_rn
+ = getRnStats all_decls `thenRn` \ msg ->
+ ioToRnMG (printErrs msg) `thenRn_`
+ returnRn ()
+
+ | otherwise = returnRn ()
+\end{code}
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