X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnIfaces.lhs;h=e62b780ea49a0c2ce8321a45b073a639fc6d0c65;hb=8fbe28ca67a6c07575aee35bfade43e967ad792e;hp=20f88177356067dc2fec551650b4eb2fa4493c9d;hpb=982006447ff7b8aa264bc018568e891313916d4d;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnIfaces.lhs b/ghc/compiler/rename/RnIfaces.lhs index 20f8817..e62b780 100644 --- a/ghc/compiler/rename/RnIfaces.lhs +++ b/ghc/compiler/rename/RnIfaces.lhs @@ -4,1069 +4,790 @@ \section[RnIfaces]{Cacheing and Renaming of Interfaces} \begin{code} -module RnIfaces ( +module RnIfaces + ( getInterfaceExports, - getImportedInstDecls, - getSpecialInstModules, getDeferredDataDecls, - importDecl, recordSlurp, - getImportVersions, getSlurpedNames, getRnStats, getImportedFixities, + recordLocalSlurps, + mkImportInfo, - checkUpToDate, loadHomeInterface, + slurpImpDecls, closeDecls, - getDeclBinders, - mkSearchPath - ) where + RecompileRequired, outOfDate, upToDate, recompileRequired + ) +where #include "HsVersions.h" -import CmdLineOpts ( opt_PruneTyDecls, opt_PruneInstDecls, - opt_D_show_rn_imports, opt_IgnoreIfacePragmas +import CmdLineOpts ( opt_IgnoreIfacePragmas, opt_NoPruneDecls ) +import HscTypes +import HsSyn ( HsDecl(..), Sig(..), TyClDecl(..), ConDecl(..), ConDetails(..), + InstDecl(..), HsType(..), hsTyVarNames, getBangType ) -import HsSyn ( HsDecl(..), TyClDecl(..), InstDecl(..), IfaceSig(..), - HsType(..), ConDecl(..), IE(..), ConDetails(..), Sig(..), - FixitySig(..), - hsDeclName, countTyClDecls, isDataDecl +import HsImpExp ( ImportDecl(..) ) +import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl ) +import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, + extractHsTyNames, extractHsCtxtTyNames, + tyClDeclFVs, ruleDeclFVs, instDeclFVs ) -import BasicTypes ( Version, NewOrData(..), IfaceFlavour(..) ) -import RdrHsSyn ( RdrNameHsDecl, RdrNameInstDecl, RdrNameTyClDecl, - RdrName(..), rdrNameOcc +import RnHiFiles ( tryLoadInterface, loadHomeInterface, loadInterface, + loadOrphanModules ) -import RnEnv ( newImportedGlobalName, addImplicitOccsRn, pprAvail, - availName, availNames, addAvailToNameSet, ifaceFlavour - ) -import RnSource ( rnHsSigType ) +import RnSource ( rnTyClDecl, rnInstDecl, rnIfaceRuleDecl ) +import RnEnv import RnMonad -import RnHsSyn ( RenamedHsDecl ) -import ParseIface ( parseIface, IfaceStuff(..) ) - -import FiniteMap ( FiniteMap, sizeFM, emptyFM, delFromFM, - lookupFM, addToFM, addToFM_C, addListToFM, - fmToList - ) -import Name ( Name {-instance NamedThing-}, OccName, - nameModule, moduleString, pprModule, isLocallyDefined, - isWiredInName, maybeWiredInTyConName, pprModule, - maybeWiredInIdName, nameUnique, NamedThing(..) +import Id ( idType ) +import Type ( namesOfType ) +import TyCon ( isSynTyCon, getSynTyConDefn ) +import Name ( Name {-instance NamedThing-}, nameOccName, + nameModule, isLocalName, nameUnique, + NamedThing(..) ) +import Name ( elemNameEnv, delFromNameEnv ) +import Module ( Module, ModuleEnv, + moduleName, isHomeModule, + ModuleName, WhereFrom(..), + emptyModuleEnv, + extendModuleEnv_C, foldModuleEnv, lookupModuleEnv, + elemModuleSet, extendModuleSet + ) import NameSet -import Id ( idType, isDataConId_maybe ) -import DataCon ( dataConTyCon, dataConType ) -import TyCon ( TyCon, tyConDataCons, isSynTyCon, getSynTyConDefn ) -import Type ( namesOfType ) -import Var ( Id ) -import SrcLoc ( mkSrcLoc, SrcLoc ) -import PrelMods ( pREL_GHC ) -import PrelInfo ( cCallishTyKeys, thinAirModules ) -import Bag -import Maybes ( MaybeErr(..), maybeToBool ) -import ListSetOps ( unionLists ) +import PrelInfo ( wiredInThingEnv, fractionalClassKeys ) +import TysWiredIn ( doubleTyCon ) +import Maybes ( orElse ) +import FiniteMap import Outputable -import Unique ( Unique ) -import StringBuffer ( StringBuffer, hGetStringBuffer ) -import FastString ( mkFastString ) -import Outputable - -import IO ( isDoesNotExistError ) -import List ( nub ) - +import Bag +import Util ( sortLt ) \end{code} - %********************************************************* %* * -\subsection{Statistics} +\subsection{Getting what a module exports} %* * %********************************************************* +@getInterfaceExports@ is called only for directly-imported modules. + \begin{code} -getRnStats :: [RenamedHsDecl] -> RnMG SDoc -getRnStats all_decls - = getIfacesRn `thenRn` \ ifaces -> - let - n_mods = sizeFM (iModMap ifaces) - - decls_imported = filter is_imported_decl all_decls - - decls_read = [decl | (_, avail, decl, True) <- nameEnvElts (iDecls ifaces), - -- Data, newtype, and class decls are in the decls_fm - -- under multiple names; the tycon/class, and each - -- constructor/class op too. - -- The 'True' selects just the 'main' decl - not (isLocallyDefined (availName avail)) - ] - - (cd_rd, dd_rd, add_rd, nd_rd, and_rd, sd_rd, vd_rd, _) = count_decls decls_read - (cd_sp, dd_sp, add_sp, nd_sp, and_sp, sd_sp, vd_sp, id_sp) = count_decls decls_imported - - (unslurped_insts, _) = iDefInsts ifaces - inst_decls_unslurped = length (bagToList unslurped_insts) - inst_decls_read = id_sp + inst_decls_unslurped - - stats = vcat - [int n_mods <> text " interfaces read", - hsep [ int cd_sp, text "class decls imported, out of", - int cd_rd, text "read"], - hsep [ int dd_sp, text "data decls imported (of which", int add_sp, - text "abstractly), out of", - int dd_rd, text "read"], - hsep [ int nd_sp, text "newtype decls imported (of which", int and_sp, - text "abstractly), out of", - int nd_rd, text "read"], - hsep [int sd_sp, text "type synonym decls imported, out of", - int sd_rd, text "read"], - hsep [int vd_sp, text "value signatures imported, out of", - int vd_rd, text "read"], - hsep [int id_sp, text "instance decls imported, out of", - int inst_decls_read, text "read"] - ] - in - returnRn (hcat [text "Renamer stats: ", stats]) - -is_imported_decl (DefD _) = False -is_imported_decl (ValD _) = False -is_imported_decl decl = not (isLocallyDefined (hsDeclName decl)) - -count_decls decls - = -- pprTrace "count_decls" (ppr decls - -- - -- $$ - -- text "=========" - -- $$ - -- ppr imported_decls - -- ) $ - (class_decls, - data_decls, abstract_data_decls, - newtype_decls, abstract_newtype_decls, - syn_decls, - val_decls, - inst_decls) +getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, [(ModuleName,Avails)]) +getInterfaceExports mod_name from + = loadInterface doc_str mod_name from `thenRn` \ iface -> + returnRn (mi_module iface, mi_exports iface) where - tycl_decls = [d | TyClD d <- decls] - (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls - abstract_data_decls = length [() | TyData DataType _ _ _ [] _ _ _ <- tycl_decls] - abstract_newtype_decls = length [() | TyData NewType _ _ _ [] _ _ _ <- tycl_decls] - - val_decls = length [() | SigD _ <- decls] - inst_decls = length [() | InstD _ <- decls] + doc_str = sep [ppr mod_name, ptext SLIT("is directly imported")] +\end{code} -\end{code} %********************************************************* %* * -\subsection{Loading a new interface file} +\subsection{Keeping track of what we've slurped, and version numbers} %* * %********************************************************* -\begin{code} -loadHomeInterface :: SDoc -> Name -> RnMG Ifaces -loadHomeInterface doc_str name - = loadInterface doc_str (nameModule name) (ifaceFlavour name) - -loadInterface :: SDoc -> Module -> IfaceFlavour -> RnMG Ifaces -loadInterface doc_str load_mod as_source - = getIfacesRn `thenRn` \ ifaces -> - let - this_mod = iMod ifaces - mod_map = iModMap ifaces - (insts, tycls_names) = iDefInsts ifaces - in - -- CHECK WHETHER WE HAVE IT ALREADY - case lookupFM mod_map load_mod of { - Just (hif, _, _) | hif `as_good_as` as_source - -> -- Already in the cache; don't re-read it - returnRn ifaces ; - other -> - - -- READ THE MODULE IN - findAndReadIface doc_str load_mod as_source `thenRn` \ read_result -> - case read_result of { - -- Check for not found - Nothing -> -- Not found, so add an empty export env to the Ifaces map - -- so that we don't look again - let - new_mod_map = addToFM mod_map load_mod (HiFile, 0, []) - new_ifaces = ifaces { iModMap = new_mod_map } - in - setIfacesRn new_ifaces `thenRn_` - failWithRn new_ifaces (noIfaceErr load_mod) ; - - -- Found and parsed! - Just (ParsedIface _ mod_vers usages exports rd_inst_mods rd_decls rd_insts) -> - - -- LOAD IT INTO Ifaces - -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined - --- names is done correctly (notably, whether this is an .hi file or .hi-boot file). - -- If we do loadExport first the wrong info gets into the cache (unless we - -- explicitly tag each export which seems a bit of a bore) - foldlRn (loadDecl load_mod as_source) - (iDecls ifaces) rd_decls `thenRn` \ new_decls -> - foldlRn (loadFixDecl load_mod as_source) - (iFixes ifaces) rd_decls `thenRn` \ new_fixities -> - mapRn loadExport exports `thenRn` \ avails_s -> - foldlRn (loadInstDecl load_mod) insts rd_insts `thenRn` \ new_insts -> - let - mod_details = (as_source, mod_vers, concat avails_s) - - -- Exclude this module from the "special-inst" modules - new_inst_mods = iInstMods ifaces `unionLists` (filter (/= this_mod) rd_inst_mods) - - new_ifaces = ifaces { iModMap = addToFM mod_map load_mod mod_details, - iDecls = new_decls, - iFixes = new_fixities, - iDefInsts = (new_insts, tycls_names), - iInstMods = new_inst_mods } - in - setIfacesRn new_ifaces `thenRn_` - returnRn new_ifaces - }} - -as_good_as HiFile any = True -as_good_as any HiBootFile = True -as_good_as _ _ = False +mkImportInof figures out what the ``usage information'' for this +moudule is; that is, what it must record in its interface file as the +things it uses. +We produce a line for every module B below the module, A, currently being +compiled: + import B ; +to record the fact that A does import B indireclty. This is used to decide +to look to look for B.hi rather than B.hi-boot when compiling a module that +imports A. This line says that A imports B, but uses nothing in it. +So we'll get an early bale-out when compiling A if B's version changes. -loadExport :: ExportItem -> RnMG [AvailInfo] -loadExport (mod, hif, entities) - = mapRn load_entity entities - where - new_name occ = newImportedGlobalName mod occ hif - - load_entity (Avail occ) - = new_name occ `thenRn` \ name -> - returnRn (Avail name) - load_entity (AvailTC occ occs) - = new_name occ `thenRn` \ name -> - mapRn new_name occs `thenRn` \ names -> - returnRn (AvailTC name names) - - -loadFixDecl :: Module -> IfaceFlavour -> FixityEnv - -> (Version, RdrNameHsDecl) - -> RnMG FixityEnv -loadFixDecl mod as_source fixity_env (version, FixD (FixitySig rdr_name fixity loc)) - = -- Ignore the version; when the fixity changes the version of - -- its 'host' entity changes, so we don't need a separate version - -- number for fixities - new_implicit_name mod as_source rdr_name `thenRn` \ name -> - let - new_fixity_env = addToNameEnv fixity_env name (FixitySig name fixity loc) - in - returnRn new_fixity_env - - -- Ignore the other sorts of decl -loadFixDecl mod as_source fixity_env other_decl = returnRn fixity_env - -loadDecl :: Module -> IfaceFlavour -> DeclsMap - -> (Version, RdrNameHsDecl) - -> RnMG DeclsMap +\begin{code} +mkImportInfo :: ModuleName -- Name of this module + -> [ImportDecl n] -- The import decls + -> RnMG [ImportVersion Name] -loadDecl mod as_source decls_map (version, decl) - = getDeclBinders new_name decl `thenRn` \ avail -> - getDeclSysBinders new_name decl `thenRn` \ sys_bndrs -> +mkImportInfo this_mod imports + = getIfacesRn `thenRn` \ ifaces -> + getHomeIfaceTableRn `thenRn` \ hit -> let - main_name = availName avail - new_decls_map = foldl add_decl decls_map - [ (name, (version,avail,decl',name==main_name)) - | name <- sys_bndrs ++ availNames avail] - add_decl decls_map (name, stuff) - = WARN( name `elemNameEnv` decls_map, ppr name ) - addToNameEnv decls_map name stuff - in - returnRn new_decls_map - where - new_name rdr_name loc = new_implicit_name mod as_source rdr_name - {- - If a signature decl is being loaded, and optIgnoreIfacePragmas is on, - we toss away unfolding information. - - Also, if the signature is loaded from a module we're importing from source, - we do the same. This is to avoid situations when compiling a pair of mutually - recursive modules, peering at unfolding info in the interface file of the other, - e.g., you compile A, it looks at B's interface file and may as a result change - its interface file. Hence, B is recompiled, maybe changing its interface file, - which will the unfolding info used in A to become invalid. Simple way out is to - just ignore unfolding info. - -} - decl' = - case decl of - SigD (IfaceSig name tp ls loc) | from_hi_boot || opt_IgnoreIfacePragmas -> - SigD (IfaceSig name tp [] loc) - _ -> decl - - from_hi_boot = case as_source of - HiBootFile -> True - other -> False - -new_implicit_name mod as_source rdr_name - = newImportedGlobalName mod (rdrNameOcc rdr_name) as_source - -loadInstDecl :: Module - -> Bag IfaceInst - -> RdrNameInstDecl - -> RnMG (Bag IfaceInst) -loadInstDecl mod_name insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc) - = - -- Find out what type constructors and classes are "gates" for the - -- instance declaration. If all these "gates" are slurped in then - -- we should slurp the instance decl too. - -- - -- We *don't* want to count names in the context part as gates, though. - -- For example: - -- instance Foo a => Baz (T a) where ... + (imp_pkg_mods, imp_home_names) = iVSlurp ifaces + pit = iPIT ifaces + + import_all_mods :: [ModuleName] + -- Modules where we imported all the names + -- (apart from hiding some, perhaps) + import_all_mods = [ m | ImportDecl m _ _ _ imp_list _ <- imports, + import_all imp_list ] + where + import_all (Just (False, _)) = False -- Imports are specified explicitly + import_all other = True -- Everything is imported + + -- mv_map groups together all the things imported and used + -- from a particular module in this package + -- We use a finite map because we want the domain + mv_map :: ModuleEnv [Name] + mv_map = foldNameSet add_mv emptyModuleEnv imp_home_names + add_mv name mv_map = extendModuleEnv_C add_item mv_map mod [name] + where + mod = nameModule name + add_item names _ = name:names + + -- In our usage list we record + -- a) Specifically: Detailed version info for imports from modules in this package + -- Gotten from iVSlurp plus import_all_mods + -- + -- b) Everything: Just the module version for imports from modules in other packages + -- Gotten from iVSlurp plus import_all_mods -- - -- Here the gates are Baz and T, but *not* Foo. - let - munged_inst_ty = case inst_ty of - HsForAllTy tvs cxt ty -> HsForAllTy tvs [] ty - other -> inst_ty + -- c) NothingAtAll: The name only of modules, Baz, in this package that are 'below' us, + -- but which we didn't need at all (this is needed only to decide whether + -- to open Baz.hi or Baz.hi-boot higher up the tree). + -- This happens when a module, Foo, that we explicitly imported has + -- 'import Baz' in its interface file, recording that Baz is below + -- Foo in the module dependency hierarchy. We want to propagate this info. + -- These modules are in a combination of HIT/PIT and iImpModInfo + -- + -- d) NothingAtAll: The name only of all orphan modules we know of (this is needed + -- so that anyone who imports us can find the orphan modules) + -- These modules are in a combination of HIT/PIT and iImpModInfo + + import_info0 = foldModuleEnv mk_imp_info [] pit + import_info1 = foldModuleEnv mk_imp_info import_info0 hit + import_info = [ (mod_name, orphans, is_boot, NothingAtAll) + | (mod_name, (orphans, is_boot)) <- fmToList (iImpModInfo ifaces) ] ++ + import_info1 + + mk_imp_info :: ModIface -> [ImportVersion Name] -> [ImportVersion Name] + mk_imp_info iface so_far + + | Just ns <- lookupModuleEnv mv_map mod -- Case (a) + = go_for_it (Specifically mod_vers maybe_export_vers + (mk_import_items ns) rules_vers) + + | mod `elemModuleSet` imp_pkg_mods -- Case (b) + = go_for_it (Everything mod_vers) + + | import_all_mod -- Case (a) and (b); the import-all part + = if is_home_pkg_mod then + go_for_it (Specifically mod_vers (Just export_vers) [] rules_vers) + else + go_for_it (Everything mod_vers) + + | is_home_pkg_mod || has_orphans -- Case (c) or (d) + = go_for_it NothingAtAll + + | otherwise = so_far + where + go_for_it exports = (mod_name, has_orphans, mi_boot iface, exports) : so_far + + mod = mi_module iface + mod_name = moduleName mod + is_home_pkg_mod = isHomeModule mod + version_info = mi_version iface + version_env = vers_decls version_info + mod_vers = vers_module version_info + rules_vers = vers_rules version_info + export_vers = vers_exports version_info + import_all_mod = mod_name `elem` import_all_mods + has_orphans = mi_orphan iface + + -- The sort is to put them into canonical order + mk_import_items ns = [(n,v) | n <- sortLt lt_occ ns, + let v = lookupNameEnv version_env n `orElse` + pprPanic "mk_whats_imported" (ppr n) + ] + where + lt_occ n1 n2 = nameOccName n1 < nameOccName n2 + + maybe_export_vers | import_all_mod = Just (vers_exports version_info) + | otherwise = Nothing in - -- We find the gates by renaming the instance type with in a - -- and returning the free variables of the type - initRnMS emptyRnEnv mod_name vanillaInterfaceMode ( - discardOccurrencesRn (rnHsSigType (text "an instance decl") munged_inst_ty) - ) `thenRn` \ (_, gate_names) -> - returnRn (((mod_name, decl), gate_names) `consBag` insts) - -vanillaInterfaceMode = InterfaceMode Compulsory + returnRn import_info \end{code} - -%******************************************************** -%* * -\subsection{Loading usage information} -%* * -%******************************************************** +%********************************************************* +%* * +\subsection{Slurping declarations} +%* * +%********************************************************* \begin{code} -checkUpToDate :: Module -> RnMG Bool -- True <=> no need to recompile -checkUpToDate mod_name - = findAndReadIface doc_str mod_name HiFile `thenRn` \ read_result -> - - -- CHECK WHETHER WE HAVE IT ALREADY - case read_result of - Nothing -> -- Old interface file not found, so we'd better bail out - traceRn (sep [ptext SLIT("Didnt find old iface"), - pprModule mod_name]) `thenRn_` - returnRn False - - Just (ParsedIface _ _ usages _ _ _ _) - -> -- Found it, so now check it - checkModUsage usages - where - -- Only look in current directory, with suffix .hi - doc_str = sep [ptext SLIT("need usage info from"), pprModule mod_name] - -checkModUsage [] = returnRn True -- Yes! Everything is up to date! - -checkModUsage ((mod, hif, old_mod_vers, whats_imported) : rest) - = loadInterface doc_str mod hif `thenRn` \ ifaces -> - let - maybe_new_mod_vers = lookupFM (iModMap ifaces) mod - Just (_, new_mod_vers, _) = maybe_new_mod_vers - in - -- If we can't find a version number for the old module then - -- bail out saying things aren't up to date - if not (maybeToBool maybe_new_mod_vers) then - traceRn (sep [ptext SLIT("Can't find version number for module"), pprModule mod]) `thenRn_` - returnRn False - else +------------------------------------------------------- +slurpImpDecls source_fvs + = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_` - -- If the module version hasn't changed, just move on - if new_mod_vers == old_mod_vers then - traceRn (sep [ptext SLIT("Module version unchanged:"), pprModule mod]) `thenRn_` - checkModUsage rest - else - traceRn (sep [ptext SLIT("Module version has changed:"), pprModule mod]) `thenRn_` + -- The current slurped-set records all local things + slurpSourceRefs source_fvs `thenRn` \ (decls, needed) -> - -- Module version changed, so check entities inside + -- Then get everything else + closeDecls decls needed - -- If the usage info wants to say "I imported everything from this module" - -- it does so by making whats_imported equal to Everything - -- In that case, we must recompile - case whats_imported of { - Everything -> traceRn (ptext SLIT("...and I needed the whole module")) `thenRn_` - returnRn False; -- Bale out - Specifically old_local_vers -> +------------------------------------------------------- +slurpSourceRefs :: FreeVars -- Variables referenced in source + -> RnMG ([RenamedHsDecl], + FreeVars) -- Un-satisfied needs +-- The declaration (and hence home module) of each gate has +-- already been loaded - -- Non-empty usage list, so check item by item - checkEntityUsage mod (iDecls ifaces) old_local_vers `thenRn` \ up_to_date -> - if up_to_date then - traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_` - checkModUsage rest -- This one's ok, so check the rest - else - returnRn False -- This one failed, so just bail out now - } +slurpSourceRefs source_fvs + = go_outer [] -- Accumulating decls + emptyFVs -- Unsatisfied needs + emptyFVs -- Accumulating gates + (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet where - doc_str = sep [ptext SLIT("need version info for"), pprModule mod] - + -- The outer loop repeatedly slurps the decls for the current gates + -- and the instance decls + + -- The outer loop is needed because consider + + go_outer decls fvs all_gates [] + = returnRn (decls, fvs) + + go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet + = traceRn (text "go_outer" <+> ppr refs) `thenRn_` + foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) -> + getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls -> + rnIfaceInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) -> + go_outer decls2 fvs2 (all_gates `plusFV` gates2) + (nameSetToList (gates2 `minusNameSet` all_gates)) + -- Knock out the all_gates because even if we don't slurp any new + -- decls we can get some apparently-new gates from wired-in names + + go_inner (decls, fvs, gates) wanted_name + = importDecl wanted_name `thenRn` \ import_result -> + case import_result of + AlreadySlurped -> returnRn (decls, fvs, gates) + InTypeEnv ty_thing -> returnRn (decls, fvs, gates `plusFV` getWiredInGates ty_thing) + + HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) -> + returnRn (TyClD new_decl : decls, + fvs1 `plusFV` fvs, + gates `plusFV` getGates source_fvs new_decl) +\end{code} -checkEntityUsage mod decls [] - = returnRn True -- Yes! All up to date! -checkEntityUsage mod decls ((occ_name,old_vers) : rest) - = newImportedGlobalName mod occ_name HiFile `thenRn` \ name -> - case lookupNameEnv decls name of +\begin{code} +------------------------------------------------------- +-- closeDecls keeps going until the free-var set is empty +closeDecls decls needed + | not (isEmptyFVs needed) + = slurpDecls decls needed `thenRn` \ (decls1, needed1) -> + closeDecls decls1 needed1 - Nothing -> -- We used it before, but it ain't there now - putDocRn (sep [ptext SLIT("No longer exported:"), ppr name]) `thenRn_` - returnRn False - - Just (new_vers,_,_,_) -- It's there, but is it up to date? - | new_vers == old_vers - -- Up to date, so check the rest - -> checkEntityUsage mod decls rest - - | otherwise - -- Out of date, so bale out - -> putDocRn (sep [ptext SLIT("Out of date:"), ppr name]) `thenRn_` - returnRn False + | otherwise + = getImportedRules `thenRn` \ rule_decls -> + case rule_decls of + [] -> returnRn decls -- No new rules, so we are done + other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' -> + let + rule_fvs = plusFVs (map ruleDeclFVs rule_decls') + in + traceRn (text "closeRules" <+> ppr rule_decls' $$ fsep (map ppr (nameSetToList rule_fvs))) `thenRn_` + closeDecls (map RuleD rule_decls' ++ decls) rule_fvs + + + +------------------------------------------------------- +-- Augment decls with any decls needed by needed. +-- Return also free vars of the new decls (only) +slurpDecls decls needed + = go decls emptyFVs (nameSetToList needed) + where + go decls fvs [] = returnRn (decls, fvs) + go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) -> + go decls1 fvs1 refs + +------------------------------------------------------- +slurpDecl decls fvs wanted_name + = importDecl wanted_name `thenRn` \ import_result -> + case import_result of + -- Found a declaration... rename it + HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) -> + returnRn (TyClD new_decl:decls, fvs1 `plusFV` fvs) + + -- No declaration... (wired in thing, or deferred, or already slurped) + other -> returnRn (decls, fvs) + + +------------------------------------------------------- +rnIfaceDecls rn decls = mapRn (rnIfaceDecl rn) decls +rnIfaceDecl rn (mod, decl) = initIfaceRnMS mod (rn decl) + +rnIfaceInstDecls decls fvs gates inst_decls + = rnIfaceDecls rnInstDecl inst_decls `thenRn` \ inst_decls' -> + returnRn (map InstD inst_decls' ++ decls, + fvs `plusFV` plusFVs (map instDeclFVs inst_decls'), + gates `plusFV` plusFVs (map getInstDeclGates inst_decls')) + +rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl) `thenRn` \ decl' -> + returnRn (decl', tyClDeclFVs decl') \end{code} -%********************************************************* -%* * -\subsection{Getting in a declaration} -%* * -%********************************************************* - \begin{code} -importDecl :: Occurrence -> RnSMode -> RnMG (Maybe RdrNameHsDecl) - -- Returns Nothing for a wired-in or already-slurped decl - -importDecl (name, loc) mode - = checkSlurped name `thenRn` \ already_slurped -> - if already_slurped then --- traceRn (sep [text "Already slurped:", ppr name]) `thenRn_` - returnRn Nothing -- Already dealt with - else - if isWiredInName name then - getWiredInDecl name mode - else - getIfacesRn `thenRn` \ ifaces -> - let - mod = nameModule name - in - if mod == iMod ifaces then -- Don't bring in decls from - addWarnRn (importDeclWarn mod name loc) `thenRn_` --- pprTrace "importDecl wierdness:" (ppr name) $ - returnRn Nothing -- the renamed module's own interface file - -- - else - getNonWiredInDecl name loc mode -\end{code} +getSlurped + = getIfacesRn `thenRn` \ ifaces -> + returnRn (iSlurp ifaces) -\begin{code} -getNonWiredInDecl :: Name -> SrcLoc -> RnSMode -> RnMG (Maybe RdrNameHsDecl) -getNonWiredInDecl needed_name loc mode - = traceRn doc_str `thenRn_` - loadHomeInterface doc_str needed_name `thenRn` \ ifaces -> - case lookupNameEnv (iDecls ifaces) needed_name of - - -- Special case for data/newtype type declarations - Just (version, avail, TyClD tycl_decl, _) | isDataDecl tycl_decl - -> getNonWiredDataDecl needed_name version avail tycl_decl `thenRn` \ (avail', maybe_decl) -> - recordSlurp (Just version) necessity avail' `thenRn_` - returnRn maybe_decl - - Just (version,avail,decl,_) - -> recordSlurp (Just version) necessity avail `thenRn_` - returnRn (Just decl) - - Nothing -> -- Can happen legitimately for "Optional" occurrences - case necessity of { - Optional -> addWarnRn (getDeclWarn needed_name loc); - other -> addErrRn (getDeclErr needed_name loc) - } `thenRn_` - returnRn Nothing +recordSlurp ifaces@(Ifaces { iDecls = (decls_map, n_slurped), + iSlurp = slurped_names, + iVSlurp = (imp_mods, imp_names) }) + avail + = ASSERT2( not (isLocalName (availName avail)), ppr avail ) + ifaces { iDecls = (decls_map', n_slurped+1), + iSlurp = new_slurped_names, + iVSlurp = new_vslurp } where - necessity = modeToNecessity mode - doc_str = sep [ptext SLIT("need decl for"), ppr needed_name, ptext SLIT("needed at"), ppr loc] + decls_map' = foldl delFromNameEnv decls_map (availNames avail) + main_name = availName avail + mod = nameModule main_name + new_slurped_names = addAvailToNameSet slurped_names avail + new_vslurp | isHomeModule mod = (imp_mods, addOneToNameSet imp_names main_name) + | otherwise = (extendModuleSet imp_mods mod, imp_names) + +recordLocalSlurps new_names + = getIfacesRn `thenRn` \ ifaces -> + setIfacesRn (ifaces { iSlurp = iSlurp ifaces `unionNameSets` new_names }) \end{code} -@getWiredInDecl@ maps a wired-in @Name@ to what it makes available. -It behaves exactly as if the wired in decl were actually in an interface file. -Specifically, - * if the wired-in name is a data type constructor or a data constructor, - it brings in the type constructor and all the data constructors; and - marks as "occurrences" any free vars of the data con. - * similarly for synonum type constructor +%********************************************************* +%* * +\subsection{Extracting the `gates'} +%* * +%********************************************************* - * if the wired-in name is another wired-in Id, it marks as "occurrences" - the free vars of the Id's type. +The gating story +~~~~~~~~~~~~~~~~~ +We want to avoid sucking in too many instance declarations. +An instance decl is only useful if the types and classes mentioned in +its 'head' are all available in the program being compiled. E.g. - * it loads the interface file for the wired-in thing for the - sole purpose of making sure that its instance declarations are available + instance (..) => C (T1 a) (T2 b) where ... -All this is necessary so that we know all types that are "in play", so -that we know just what instances to bring into scope. - -\begin{code} -getWiredInDecl name mode - = initRnMS emptyRnEnv mod_name new_mode - get_wired `thenRn` \ avail -> - recordSlurp Nothing necessity avail `thenRn_` +is only useful if C, T1 and T2 are all "available". So we keep +instance decls that have been parsed from .hi files, but not yet +slurped in, in a pool called the 'gated instance pool'. +Each has its set of 'gates': {C, T1, T2} in the above example. - -- Force in the home module in case it has instance decls for - -- the thing we are interested in. - -- - -- Mini hack 1: no point for non-tycons/class; and if we - -- do this we find PrelNum trying to import PackedString, - -- because PrelBase's .hi file mentions PackedString.unpackString - -- But PackedString.hi isn't built by that point! - -- - -- Mini hack 2; GHC is guaranteed not to have - -- instance decls, so it's a waste of time to read it - -- - -- NB: We *must* look at the availName of the slurped avail, - -- not the name passed to getWiredInDecl! Why? Because if a data constructor - -- or class op is passed to getWiredInDecl we'll pull in the whole data/class - -- decl, and recordSlurp will record that fact. But since the data constructor - -- isn't a tycon/class we won't force in the home module. And even if the - -- type constructor/class comes along later, loadDecl will say that it's already - -- been slurped, so getWiredInDecl won't even be called. Pretty obscure bug, this was. - let - main_name = availName avail - main_is_tc = case avail of { AvailTC _ _ -> True; Avail _ -> False } - mod = nameModule main_name - doc_str = sep [ptext SLIT("need home module for wired in thing"), ppr name] - in - (if not main_is_tc || mod == pREL_GHC then - returnRn () - else - loadHomeInterface doc_str main_name `thenRn_` - returnRn () - ) `thenRn_` +More precisely, the gates of a module are the types and classes +that are mentioned in: - returnRn Nothing -- No declaration to process further - where - necessity = modeToNecessity mode - new_mode = case mode of - InterfaceMode _ -> mode - SourceMode -> vanillaInterfaceMode + a) the source code + b) the type of an Id that's mentioned in the source code + [includes constructors and selectors] + c) the RHS of a type synonym that is a gate + d) the superclasses of a class that is a gate + e) the context of an instance decl that is slurped in - get_wired | is_tycon -- ... a type constructor - = get_wired_tycon the_tycon +We slurp in an instance decl from the gated instance pool iff + + all its gates are either in the gates of the module, + or are a previously-loaded class. - | maybeToBool maybe_data_con -- ... a wired-in data constructor - = get_wired_tycon (dataConTyCon data_con) +The latter constraint is because there might have been an instance +decl slurped in during an earlier compilation, like this: - | otherwise -- ... a wired-in non data-constructor - = get_wired_id the_id + instance Foo a => Baz (Maybe a) where ... - mod_name = nameModule name - maybe_wired_in_tycon = maybeWiredInTyConName name - is_tycon = maybeToBool maybe_wired_in_tycon - maybe_wired_in_id = maybeWiredInIdName name - Just the_tycon = maybe_wired_in_tycon - Just the_id = maybe_wired_in_id - maybe_data_con = isDataConId_maybe the_id - Just data_con = maybe_data_con +In the module being compiled we might need (Baz (Maybe T)), where T +is defined in this module, and hence we need (Foo T). So @Foo@ becomes +a gate. But there's no way to 'see' that, so we simply treat all +previously-loaded classes as gates. +Consructors and class operations +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +When we import a declaration like -get_wired_id id - = addImplicitOccsRn id_mentions `thenRn_` - returnRn (Avail (getName id)) - where - id_mentions = nameSetToList (namesOfType ty) - ty = idType id + data T = T1 Wibble | T2 Wobble -get_wired_tycon tycon - | isSynTyCon tycon - = addImplicitOccsRn (nameSetToList mentioned) `thenRn_` - returnRn (AvailTC tc_name [tc_name]) - where - tc_name = getName tycon - (tyvars,ty) = getSynTyConDefn tycon - mentioned = namesOfType ty `minusNameSet` mkNameSet (map getName tyvars) - -get_wired_tycon tycon - | otherwise -- data or newtype - = addImplicitOccsRn (nameSetToList mentioned) `thenRn_` - returnRn (AvailTC tycon_name (tycon_name : map getName data_cons)) - where - tycon_name = getName tycon - data_cons = tyConDataCons tycon - mentioned = foldr (unionNameSets . namesOfType . dataConType) emptyNameSet data_cons -\end{code} +we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless} +@T1@, @T2@ respectively are mentioned by the user program. If only +@T@ is mentioned we want only @T@ to be a gate; that way we don't suck +in useless instance decls for (say) @Eq Wibble@, when they can't +possibly be useful. +And that's just what (b) says: we only treat T1's type as a gate if +T1 is mentioned. getGates, which deals with decls we are slurping in, +has to be a bit careful, because a mention of T1 will slurp in T's whole +declaration. - -%********************************************************* -%* * -\subsection{Getting what a module exports} -%* * -%********************************************************* +----------------------------- +@getGates@ takes a newly imported (and renamed) decl, and the free +vars of the source program, and extracts from the decl the gate names. \begin{code} -getInterfaceExports :: Module -> IfaceFlavour -> RnMG Avails -getInterfaceExports mod as_source - = loadInterface doc_str mod as_source `thenRn` \ ifaces -> - case lookupFM (iModMap ifaces) mod of - Nothing -> -- Not there; it must be that the interface file wasn't found; - -- the error will have been reported already. - -- (Actually loadInterface should put the empty export env in there - -- anyway, but this does no harm.) - returnRn [] - - Just (_, _, avails) -> returnRn avails - where - doc_str = sep [pprModule mod, ptext SLIT("is directly imported")] -\end{code} +getGates :: FreeVars -- Things mentioned in the source program + -> RenamedTyClDecl + -> FreeVars +getGates source_fvs decl + = get_gates (\n -> n `elemNameSet` source_fvs) decl -%********************************************************* -%* * -\subsection{Data type declarations are handled specially} -%* * -%********************************************************* +get_gates is_used (IfaceSig _ ty _ _) + = extractHsTyNames ty -Data type declarations get special treatment. If we import a data type decl -with all its constructors, we end up importing all the types mentioned in -the constructors' signatures, and hence {\em their} data type decls, and so on. -In effect, we get the transitive closure of data type decls. Worse, this drags -in tons on instance decls, and their unfoldings, and so on. +get_gates is_used (ClassDecl ctxt cls tvs _ sigs _ _ _ ) + = (delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs) + (hsTyVarNames tvs) + `addOneToNameSet` cls) + `plusFV` maybe_double + where + get (ClassOpSig n _ ty _) + | is_used n = extractHsTyNames ty + | otherwise = emptyFVs + + -- If we load any numeric class that doesn't have + -- Int as an instance, add Double to the gates. + -- This takes account of the fact that Double might be needed for + -- defaulting, but we don't want to load Double (and all its baggage) + -- if the more exotic classes aren't used at all. + maybe_double | nameUnique cls `elem` fractionalClassKeys + = unitFV (getName doubleTyCon) + | otherwise + = emptyFVs + +get_gates is_used (TySynonym tycon tvs ty _) + = delListFromNameSet (extractHsTyNames ty) (hsTyVarNames tvs) + -- A type synonym type constructor isn't a "gate" for instance decls + +get_gates is_used (TyData _ ctxt tycon tvs cons _ _ _ _ _) + = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons) + (hsTyVarNames tvs) + `addOneToNameSet` tycon + where + get (ConDecl n _ tvs ctxt details _) + | is_used n + -- If the constructor is method, get fvs from all its fields + = delListFromNameSet (get_details details `plusFV` + extractHsCtxtTyNames ctxt) + (hsTyVarNames tvs) + get (ConDecl n _ tvs ctxt (RecCon fields) _) + -- Even if the constructor isn't mentioned, the fields + -- might be, as selectors. They can't mention existentially + -- bound tyvars (typechecker checks for that) so no need for + -- the deleteListFromNameSet part + = foldr (plusFV . get_field) emptyFVs fields + + get other_con = emptyFVs -If only the type constructor is mentioned, then all this is a waste of time. -If any of the data constructors are mentioned then we really have to -drag in the whole declaration. + get_details (VanillaCon tys) = plusFVs (map get_bang tys) + get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2 + get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields] -So when we import the type constructor for a @data@ or @newtype@ decl, we -put it in the "deferred data/newtype decl" pile in Ifaces. Right at the end -we slurp these decls, if they havn't already been dragged in by an occurrence -of a constructor. + get_field (fs,t) | any is_used fs = get_bang t + | otherwise = emptyFVs -\begin{code} -getNonWiredDataDecl needed_name - version - avail@(AvailTC tycon_name _) - ty_decl@(TyData new_or_data context tycon tyvars condecls derivings pragmas src_loc) - | needed_name == tycon_name - && opt_PruneTyDecls - -- don't prune newtypes, as the code generator may - -- want to peer inside a newtype type constructor - -- (ClosureInfo.fun_result_ty is the culprit.) - && not (new_or_data == NewType) - && not (nameUnique needed_name `elem` cCallishTyKeys) - -- Hack! Don't prune these tycons whose constructors - -- the desugarer must be able to see when desugaring - -- a CCall. Ugh! - - = -- Need the type constructor; so put it in the deferred set for now - getIfacesRn `thenRn` \ ifaces -> - let - deferred_data_decls = iDefData ifaces - new_ifaces = ifaces {iDefData = new_deferred_data_decls} - - no_constr_ty_decl = TyData new_or_data [] tycon tyvars [] derivings pragmas src_loc - new_deferred_data_decls = addToNameEnv deferred_data_decls tycon_name - (nameModule tycon_name, no_constr_ty_decl) - -- Nota bene: we nuke both the constructors and the context in the deferred decl. - -- If we don't nuke the context then renaming the deferred data decls can give - -- new unresolved names (for the classes). This could be handled, but there's - -- no point. If the data type is completely abstract then we aren't interested - -- its context. - in - setIfacesRn new_ifaces `thenRn_` - returnRn (AvailTC tycon_name [tycon_name], Nothing) + get_bang bty = extractHsTyNames (getBangType bty) +\end{code} - | otherwise - = -- Need a data constructor, so delete the data decl from the deferred set if it's there - getIfacesRn `thenRn` \ ifaces -> - let - deferred_data_decls = iDefData ifaces - new_ifaces = ifaces {iDefData = new_deferred_data_decls} +@getWiredInGates@ is just like @getGates@, but it sees a previously-loaded +thing rather than a declaration. - new_deferred_data_decls = delFromNameEnv deferred_data_decls tycon_name - in - setIfacesRn new_ifaces `thenRn_` - returnRn (avail, Just (TyClD ty_decl)) +\begin{code} +getWiredInGates :: TyThing -> FreeVars +-- The TyThing is one that we already have in our type environment, either +-- a) because the TyCon or Id is wired in, or +-- b) from a previous compile +-- Either way, we might have instance decls in the (persistent) collection +-- of parsed-but-not-slurped instance decls that should be slurped in. +-- This might be the first module that mentions both the type and the class +-- for that instance decl, even though both the type and the class were +-- mentioned in other modules, and hence are in the type environment + +getWiredInGates (AnId the_id) = namesOfType (idType the_id) +getWiredInGates (AClass cl) = emptyFVs -- The superclasses must also be previously + -- loaded, and hence are automatically gates +getWiredInGates (ATyCon tc) + | isSynTyCon tc = delListFromNameSet (namesOfType ty) (map getName tyvars) + | otherwise = unitFV (getName tc) + where + (tyvars,ty) = getSynTyConDefn tc + +getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty \end{code} \begin{code} -getDeferredDataDecls :: RnMG [(Module, RdrNameTyClDecl)] -getDeferredDataDecls - = getIfacesRn `thenRn` \ ifaces -> +getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameInstDecl)] +getImportedInstDecls gates + = -- First, load any orphan-instance modules that aren't aready loaded + -- Orphan-instance modules are recorded in the module dependecnies + getIfacesRn `thenRn` \ ifaces -> let - deferred_list = nameEnvElts (iDefData ifaces) - trace_msg = hang (text "Slurping abstract data/newtype decls for: ") - 4 (ppr (map fst deferred_list)) + orphan_mods = + [mod | (mod, (True, _)) <- fmToList (iImpModInfo ifaces)] in - traceRn trace_msg `thenRn_` - returnRn deferred_list -\end{code} - - -%********************************************************* -%* * -\subsection{Instance declarations are handled specially} -%* * -%********************************************************* - -\begin{code} -getImportedInstDecls :: RnMG [(Module,RdrNameInstDecl)] -getImportedInstDecls - = -- First load any special-instance modules that aren't aready loaded - getSpecialInstModules `thenRn` \ inst_mods -> - mapRn load_it inst_mods `thenRn_` + loadOrphanModules orphan_mods `thenRn_` -- Now we're ready to grab the instance declarations -- Find the un-gated ones and return them, -- removing them from the bag kept in Ifaces - getIfacesRn `thenRn` \ ifaces -> + getIfacesRn `thenRn` \ ifaces -> + getTypeEnvRn `thenRn` \ lookup -> let - (insts, tycls_names) = iDefInsts ifaces - - -- An instance decl is ungated if all its gates have been slurped - select_ungated :: IfaceInst -- A gated inst decl + (decls, new_insts) = selectGated gates lookup (iInsts ifaces) + in + setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_` - -> ([(Module, RdrNameInstDecl)], [IfaceInst]) -- Accumulator + traceRn (sep [text "getImportedInstDecls:", + nest 4 (fsep (map ppr gate_list)), + text "Slurped" <+> int (length decls) <+> text "instance declarations", + nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_` + returnRn decls + where + gate_list = nameSetToList gates - -> ([(Module, RdrNameInstDecl)], -- The ungated ones - [IfaceInst]) -- Still gated, but with - -- depeleted gates - select_ungated (decl,gates) (ungated_decls, gated_decls) - | isEmptyNameSet remaining_gates - = (decl : ungated_decls, gated_decls) - | otherwise - = (ungated_decls, (decl, remaining_gates) : gated_decls) - where - remaining_gates = gates `minusNameSet` tycls_names +ppr_brief_inst_decl (mod, InstDecl inst_ty _ _ _ _) + = case inst_ty of + HsForAllTy _ _ tau -> ppr tau + other -> ppr inst_ty - (un_gated_insts, still_gated_insts) = foldrBag select_ungated ([], []) insts - - new_ifaces = ifaces {iDefInsts = (listToBag still_gated_insts, tycls_names)} - -- NB: don't throw away tycls_names; - -- we may comre across more instance decls +getImportedRules :: RnMG [(Module,RdrNameRuleDecl)] +getImportedRules + | opt_IgnoreIfacePragmas = returnRn [] + | otherwise + = getIfacesRn `thenRn` \ ifaces -> + getTypeEnvRn `thenRn` \ lookup -> + let + gates = iSlurp ifaces -- Anything at all that's been slurped + rules = iRules ifaces + (decls, new_rules) = selectGated gates lookup rules in - traceRn (sep [text "getInstDecls:", fsep (map ppr (nameSetToList tycls_names))]) `thenRn_` - setIfacesRn new_ifaces `thenRn_` - returnRn un_gated_insts - where - load_it mod = loadInterface (doc_str mod) mod HiFile - doc_str mod = sep [pprModule mod, ptext SLIT("is a special-instance module")] - + if null decls then + returnRn [] + else + setIfacesRn (ifaces { iRules = new_rules }) `thenRn_` + traceRn (sep [text "getImportedRules:", + text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_` + returnRn decls + +selectGated gates lookup (decl_bag, n_slurped) + -- Select only those decls whose gates are *all* in 'gates' + -- or are a class in 'lookup' +#ifdef DEBUG + | opt_NoPruneDecls -- Just to try the effect of not gating at all + = let + decls = foldrBag (\ (_,d) ds -> d:ds) [] decl_bag -- Grab them all + in + (decls, (emptyBag, n_slurped + length decls)) -getSpecialInstModules :: RnMG [Module] -getSpecialInstModules - = getIfacesRn `thenRn` \ ifaces -> - returnRn (iInstMods ifaces) + | otherwise +#endif + = case foldrBag select ([], emptyBag) decl_bag of + (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls)) + where + available n = n `elemNameSet` gates + || case lookup n of { Just (AClass c) -> True; other -> False } -getImportedFixities :: RnMG FixityEnv -getImportedFixities - = getIfacesRn `thenRn` \ ifaces -> - returnRn (iFixes ifaces) + select (reqd, decl) (yes, no) + | all available reqd = (decl:yes, no) + | otherwise = (yes, (reqd,decl) `consBag` no) \end{code} %********************************************************* %* * -\subsection{Keeping track of what we've slurped, and version numbers} +\subsection{Getting in a declaration} %* * %********************************************************* -getImportVersions figures out what the "usage information" for this moudule is; -that is, what it must record in its interface file as the things it uses. -It records: - - anything reachable from its body code - - any module exported with a "module Foo". - -Why the latter? Because if Foo changes then this module's export list -will change, so we must recompile this module at least as far as -making a new interface file --- but in practice that means complete -recompilation. - -What about this? - module A( f, g ) where module B( f ) where - import B( f ) f = h 3 - g = ... h = ... - -Should we record B.f in A's usages? In fact we don't. Certainly, if -anything about B.f changes than anyone who imports A should be recompiled; -they'll get an early exit if they don't use B.f. However, even if B.f -doesn't change at all, B.h may do so, and this change may not be reflected -in f's version number. So there are two things going on when compiling module A: - -1. Are A.o and A.hi correct? Then we can bale out early. -2. Should modules that import A be recompiled? - -For (1) it is slightly harmful to record B.f in A's usages, because a change in -B.f's version will provoke full recompilation of A, producing an identical A.o, -and A.hi differing only in its usage-version of B.f (which isn't used by any importer). - -For (2), because of the tricky B.h question above, we ensure that A.hi is touched -(even if identical to its previous version) if A's recompilation was triggered by -an imported .hi file date change. Given that, there's no need to record B.f in -A's usages. - -On the other hand, if A exports "module B" then we *do* count module B among -A's usages, because we must recompile A to ensure that A.hi changes appropriately. - \begin{code} -getImportVersions :: Module -- Name of this module - -> Maybe [IE any] -- Export list for this module - -> RnMG (VersionInfo Name) -- Version info for these names +importDecl :: Name -> RnMG ImportDeclResult + +data ImportDeclResult + = AlreadySlurped + | InTypeEnv TyThing + | HereItIs (Module, RdrNameTyClDecl) + +importDecl name + = -- STEP 1: Check if we've slurped it in while compiling this module + getIfacesRn `thenRn` \ ifaces -> + if name `elemNameSet` iSlurp ifaces then + returnRn AlreadySlurped + else -getImportVersions this_mod exports - = getIfacesRn `thenRn` \ ifaces -> - let - mod_map = iModMap ifaces - imp_names = iVSlurp ifaces + -- STEP 2: Check if it's already in the type environment + getTypeEnvRn `thenRn` \ lookup -> + case lookup name of { + Just ty_thing | name `elemNameEnv` wiredInThingEnv + -> -- When we find a wired-in name we must load its home + -- module so that we find any instance decls lurking therein + loadHomeInterface wi_doc name `thenRn_` + returnRn (InTypeEnv ty_thing) - -- mv_map groups together all the things imported from a particular module. - mv_map, mv_map_mod :: FiniteMap Module (WhatsImported Name) + | otherwise + -> returnRn (InTypeEnv ty_thing) ; - mv_map_mod = foldl add_mod emptyFM export_mods - -- mv_map_mod records all the modules that have a "module M" - -- in this module's export list with an "Everything" + Nothing -> - mv_map = foldl add_mv mv_map_mod imp_names - -- mv_map adds the version numbers of things exported individually + -- STEP 3: OK, we have to slurp it in from an interface file + -- First load the interface file + traceRn nd_doc `thenRn_` + loadHomeInterface nd_doc name `thenRn_` + getIfacesRn `thenRn` \ ifaces -> - mk_version_info (mod, local_versions) - = case lookupFM mod_map mod of - Just (hif, version, _) -> (mod, hif, version, local_versions) + -- STEP 4: Get the declaration out + let + (decls_map, _) = iDecls ifaces in - returnRn (map mk_version_info (fmToList mv_map)) + case lookupNameEnv decls_map name of + Just (avail,_,decl) + -> setIfacesRn (recordSlurp ifaces avail) `thenRn_` + returnRn (HereItIs decl) + + Nothing + -> addErrRn (getDeclErr name) `thenRn_` + returnRn AlreadySlurped + } where - export_mods = case exports of - Nothing -> [] - Just es -> [mod | IEModuleContents mod <- es, mod /= this_mod] + wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name + nd_doc = ptext SLIT("need decl for") <+> ppr name - add_mv mv_map v@(name, version) - = addToFM_C add_item mv_map mod (Specifically [v]) - where - mod = nameModule name +\end{code} - add_item Everything _ = Everything - add_item (Specifically xs) _ = Specifically (v:xs) - add_mod mv_map mod = addToFM mv_map mod Everything -\end{code} +%******************************************************** +%* * +\subsection{Checking usage information} +%* * +%******************************************************** + +@recompileRequired@ is called from the HscMain. It checks whether +a recompilation is required. It needs access to the persistent state, +finder, etc, because it may have to load lots of interface files to +check their versions. \begin{code} -checkSlurped name - = getIfacesRn `thenRn` \ ifaces -> - returnRn (name `elemNameSet` iSlurp ifaces) +type RecompileRequired = Bool +upToDate = False -- Recompile not required +outOfDate = True -- Recompile required + +recompileRequired :: FilePath -- Only needed for debug msgs + -> Bool -- Source unchanged + -> ModIface -- Old interface + -> RnMG RecompileRequired +recompileRequired iface_path source_unchanged iface + = traceHiDiffsRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_` + + -- CHECK WHETHER THE SOURCE HAS CHANGED + if not source_unchanged then + traceHiDiffsRn (nest 4 (text "Source file changed or recompilation check turned off")) `thenRn_` + returnRn outOfDate + else -getSlurpedNames :: RnMG NameSet -getSlurpedNames - = getIfacesRn `thenRn` \ ifaces -> - returnRn (iSlurp ifaces) + -- Source code unchanged and no errors yet... carry on + checkList [checkModUsage u | u <- mi_usages iface] -recordSlurp maybe_version necessity avail - = {- traceRn (hsep [text "Record slurp:", pprAvail avail, - -- NB PprForDebug prints export flag, which is too - -- strict; it's a knot-tied thing in RnNames - case necessity of {Compulsory -> text "comp"; Optional -> text "opt" } ]) `thenRn_` - -} - getIfacesRn `thenRn` \ ifaces -> +checkList :: [RnMG RecompileRequired] -> RnMG RecompileRequired +checkList [] = returnRn upToDate +checkList (check:checks) = check `thenRn` \ recompile -> + if recompile then + returnRn outOfDate + else + checkList checks +\end{code} + +\begin{code} +checkModUsage :: ImportVersion Name -> RnMG RecompileRequired +-- Given the usage information extracted from the old +-- M.hi file for the module being compiled, figure out +-- whether M needs to be recompiled. + +checkModUsage (mod_name, _, _, NothingAtAll) + -- If CurrentModule.hi contains + -- import Foo :: ; + -- then that simply records that Foo lies below CurrentModule in the + -- hierarchy, but CurrentModule doesn't depend in any way on Foo. + -- In this case we don't even want to open Foo's interface. + = up_to_date (ptext SLIT("Nothing used from:") <+> ppr mod_name) + +checkModUsage (mod_name, _, is_boot, whats_imported) + = -- Load the imported interface is possible + -- We use tryLoadInterface, because failure is not an error + -- (might just be that the old .hi file for this module is out of date) + -- We use ImportByUser/ImportByUserSource as the 'from' flag, + -- a) because we need to know whether to load the .hi-boot file + -- b) because loadInterface things matters are amiss if we + -- ImportBySystem an interface it knows nothing about let - Ifaces { iSlurp = slurped_names, - iVSlurp = imp_names, - iDefInsts = (insts, tycls_names) } = ifaces - - new_slurped_names = addAvailToNameSet slurped_names avail - - new_imp_names = case maybe_version of - Just version -> (availName avail, version) : imp_names - Nothing -> imp_names - - -- Add to the names that will let in instance declarations; - -- but only (a) if it's a type/class - -- (b) if it's compulsory (unless the test flag opt_PruneInstDecls is off) - new_tycls_names = case avail of - AvailTC tc _ | not opt_PruneInstDecls || - case necessity of {Optional -> False; Compulsory -> True } - -> tycls_names `addOneToNameSet` tc - otherwise -> tycls_names - - new_ifaces = ifaces { iSlurp = new_slurped_names, - iVSlurp = new_imp_names, - iDefInsts = (insts, new_tycls_names) } + doc_str = sep [ptext SLIT("need version info for"), ppr mod_name] + from | is_boot = ImportByUserSource + | otherwise = ImportByUser in - setIfacesRn new_ifaces -\end{code} + tryLoadInterface doc_str mod_name from `thenRn` \ (iface, maybe_err) -> + case maybe_err of { + Just err -> out_of_date (sep [ptext SLIT("Can't find version number for module"), + ppr mod_name]) ; + -- Couldn't find or parse a module mentioned in the + -- old interface file. Don't complain -- it might just be that + -- the current module doesn't need that import and it's been deleted -%********************************************************* -%* * -\subsection{Getting binders out of a declaration} -%* * -%********************************************************* + Nothing -> + let + new_vers = mi_version iface + new_decl_vers = vers_decls new_vers + in + case whats_imported of { -- NothingAtAll dealt with earlier -@getDeclBinders@ returns the names for a @RdrNameHsDecl@. -It's used for both source code (from @availsFromDecl@) and interface files -(from @loadDecl@). + Everything old_mod_vers -> checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile -> + if recompile then + out_of_date (ptext SLIT("...and I needed the whole module")) + else + returnRn upToDate ; -It doesn't deal with source-code specific things: ValD, DefD. They -are handled by the sourc-code specific stuff in RnNames. + Specifically old_mod_vers maybe_old_export_vers old_decl_vers old_rule_vers -> -\begin{code} -getDeclBinders :: (RdrName -> SrcLoc -> RnMG Name) -- New-name function - -> RdrNameHsDecl - -> RnMG AvailInfo - -getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ src_loc)) - = new_name tycon src_loc `thenRn` \ tycon_name -> - getConFieldNames new_name condecls `thenRn` \ sub_names -> - returnRn (AvailTC tycon_name (tycon_name : nub sub_names)) - -- The "nub" is because getConFieldNames can legitimately return duplicates, - -- when a record declaration has the same field in multiple constructors - -getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc)) - = new_name tycon src_loc `thenRn` \ tycon_name -> - returnRn (AvailTC tycon_name [tycon_name]) - -getDeclBinders new_name (TyClD (ClassDecl _ cname _ sigs _ _ tname dname src_loc)) - = new_name cname src_loc `thenRn` \ class_name -> - - -- Record the names for the class ops - mapRn (getClassOpNames new_name) sigs `thenRn` \ sub_names -> - - returnRn (AvailTC class_name (class_name : sub_names)) - -getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc)) - = new_name var src_loc `thenRn` \ var_name -> - returnRn (Avail var_name) - -getDeclBinders new_name (FixD _) = returnRn NotAvailable -getDeclBinders new_name (ForD _) = returnRn NotAvailable -getDeclBinders new_name (DefD _) = returnRn NotAvailable -getDeclBinders new_name (InstD _) = returnRn NotAvailable - ----------------- -getConFieldNames new_name (ConDecl con _ _ (RecCon fielddecls) src_loc : rest) - = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs -> - getConFieldNames new_name rest `thenRn` \ ns -> - returnRn (cfs ++ ns) - where - fields = concat (map fst fielddecls) + -- CHECK MODULE + checkModuleVersion old_mod_vers new_vers `thenRn` \ recompile -> + if not recompile then + returnRn upToDate + else + + -- CHECK EXPORT LIST + if checkExportList maybe_old_export_vers new_vers then + out_of_date (ptext SLIT("Export list changed")) + else -getConFieldNames new_name (ConDecl con _ _ _ src_loc : rest) - = new_name con src_loc `thenRn` \ n -> - getConFieldNames new_name rest `thenRn` \ ns -> - returnRn (n:ns) + -- CHECK RULES + if old_rule_vers /= vers_rules new_vers then + out_of_date (ptext SLIT("Rules changed")) + else -getConFieldNames new_name [] = returnRn [] + -- CHECK ITEMS ONE BY ONE + checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenRn` \ recompile -> + if recompile then + returnRn outOfDate -- This one failed, so just bail out now + else + up_to_date (ptext SLIT("...but the bits I use haven't.")) -getClassOpNames new_name (ClassOpSig op _ _ src_loc) = new_name op src_loc -\end{code} + }} -@getDeclSysBinders@ gets the implicit binders introduced by a decl. -A the moment that's just the tycon and datacon that come with a class decl. -They aren'te returned by getDeclBinders because they aren't in scope; -but they should be put into the DeclsMap of this module. +------------------------ +checkModuleVersion old_mod_vers new_vers + | vers_module new_vers == old_mod_vers + = up_to_date (ptext SLIT("Module version unchanged")) -\begin{code} -getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ sigs _ _ tname dname src_loc)) - = new_name dname src_loc `thenRn` \ datacon_name -> - new_name tname src_loc `thenRn` \ tycon_name -> - returnRn [tycon_name, datacon_name] + | otherwise + = out_of_date (ptext SLIT("Module version has changed")) -getDeclSysBinders new_name other_decl - = returnRn [] -\end{code} +------------------------ +checkExportList Nothing new_vers = upToDate +checkExportList (Just v) new_vers = v /= vers_exports new_vers -%********************************************************* -%* * -\subsection{Reading an interface file} -%* * -%********************************************************* +------------------------ +checkEntityUsage new_vers (name,old_vers) + = case lookupNameEnv new_vers name of -\begin{code} -findAndReadIface :: SDoc -> Module - -> IfaceFlavour - -> RnMG (Maybe ParsedIface) - -- Nothing <=> file not found, or unreadable, or illegible - -- Just x <=> successfully found and parsed -findAndReadIface doc_str mod_name as_source - = traceRn trace_msg `thenRn_` - -- we keep two maps for interface files, - -- one for 'normal' ones, the other for .hi-boot files, - -- hence the need to signal which kind we're interested. - getModuleHiMap as_source `thenRn` \ himap -> - case (lookupFM himap (moduleString mod_name)) of - -- Found the file - Just fpath -> readIface fpath - -- Hack alert! When compiling PrelBase we have to load the - -- decls for packCString# and friends; they are 'thin-air' Ids - -- (see PrelInfo.lhs). So if we don't find the HiFile we quietly - -- look for a .hi-boot file instead, and use that - Nothing | thinAirLoop mod_name as_source - -> findAndReadIface doc_str mod_name HiBootFile - | otherwise - -> traceRn (ptext SLIT("...failed")) `thenRn_` - returnRn Nothing - where - thinAirLoop mod_name HiFile = mod_name `elem` thinAirModules - thinAirLoop mod_name hif = False - - trace_msg = sep [hsep [ptext SLIT("Reading"), - case as_source of { HiBootFile -> ptext SLIT("[boot]"); other -> empty}, - ptext SLIT("interface for"), - pprModule mod_name <> semi], - nest 4 (ptext SLIT("reason:") <+> doc_str)] -\end{code} + Nothing -> -- We used it before, but it ain't there now + out_of_date (sep [ptext SLIT("No longer exported:"), ppr name]) -@readIface@ tries just the one file. + Just new_vers -- It's there, but is it up to date? + | new_vers == old_vers -> returnRn upToDate + | otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name]) -\begin{code} -readIface :: String -> RnMG (Maybe ParsedIface) - -- Nothing <=> file not found, or unreadable, or illegible - -- Just x <=> successfully found and parsed -readIface file_path - = ioToRnMG (hGetStringBuffer file_path) `thenRn` \ read_result -> - case read_result of - Right contents -> - case parseIface contents (mkSrcLoc (mkFastString file_path) 1) of - Failed err -> failWithRn Nothing err - Succeeded (PIface iface) -> - if opt_D_show_rn_imports then - putDocRn (hcat[ptext SLIT("Read "), text file_path]) `thenRn_` - returnRn (Just iface) - else - returnRn (Just iface) - - Left err -> - if isDoesNotExistError err then - returnRn Nothing - else - failWithRn Nothing (cannaeReadFile file_path err) +up_to_date msg = traceHiDiffsRn msg `thenRn_` returnRn upToDate +out_of_date msg = traceHiDiffsRn msg `thenRn_` returnRn outOfDate \end{code} -%********************************************************* -%* * -\subsection{Utils} -%* * -%********************************************************* - -@mkSearchPath@ takes a string consisting of a colon-separated list -of directories and corresponding suffixes, and turns it into a list -of (directory, suffix) pairs. For example: - -\begin{verbatim} - mkSearchPath "foo%.hi:.%.p_hi:baz%.mc_hi" - = [("foo",".hi"),( ".", ".p_hi"), ("baz",".mc_hi")] -\begin{verbatim} - -\begin{code} -mkSearchPath :: Maybe String -> SearchPath -mkSearchPath Nothing = [(".",".hi")] -mkSearchPath (Just s) - = go s - where - go "" = [] - go s = - case span (/= '%') s of - (dir,'%':rs) -> - case span (/= ':') rs of - (hisuf,_:rest) -> (dir,hisuf):go rest - (hisuf,[]) -> [(dir,hisuf)] -\end{code} %********************************************************* %* * @@ -1075,30 +796,8 @@ mkSearchPath (Just s) %********************************************************* \begin{code} -noIfaceErr filename - = hcat [ptext SLIT("Could not find valid interface file "), - quotes (pprModule filename)] - -cannaeReadFile file err - = hcat [ptext SLIT("Failed in reading file: "), - text file, - ptext SLIT("; error="), - text (show err)] - -getDeclErr name loc - = sep [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name), - ptext SLIT("needed at") <+> ppr loc] - -getDeclWarn name loc - = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name), - ptext SLIT("desired at") <+> ppr loc] - -importDeclWarn mod name loc - = sep [ptext SLIT("Compiler tried to import decl from interface file with same name as module."), - ptext SLIT("(possible cause: module name clashes with interface file already in scope.)") - ] $$ - hsep [ptext SLIT("Interface:"), quotes (pprModule mod), comma, ptext SLIT("name:"), quotes (ppr name), - comma, ptext SLIT("desired at:"), ppr loc - ] - +getDeclErr name + = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name), + ptext SLIT("from module") <+> quotes (ppr (nameModule name)) + ] \end{code}