{-# LANGUAGE CPP #-} {-# LANGUAGE MultiWayIf #-} -- | Module for detecting if recompilation is required module GHC.Iface.Recomp ( checkOldIface , RecompileRequired(..) , recompileRequired , addFingerprints ) where #include "HsVersions.h" import GHC.Prelude import GHC.Driver.Backend import GHC.Driver.Env import GHC.Driver.Session import GHC.Driver.Ppr import GHC.Driver.Plugins ( PluginRecompile(..), PluginWithArgs(..), pluginRecompile', plugins ) import GHC.Iface.Syntax import GHC.Iface.Recomp.Binary import GHC.Iface.Load import GHC.Iface.Recomp.Flags import GHC.Core import GHC.Tc.Utils.Monad import GHC.Hs import GHC.Data.Graph.Directed import GHC.Data.Maybe import GHC.Data.FastString import GHC.Utils.Error import GHC.Utils.Panic import GHC.Utils.Outputable as Outputable import GHC.Utils.Misc as Utils hiding ( eqListBy ) import GHC.Utils.Binary import GHC.Utils.Fingerprint import GHC.Utils.Exception import GHC.Types.Annotations import GHC.Types.Name import GHC.Types.Name.Set import GHC.Types.SrcLoc import GHC.Types.Unique import GHC.Types.Unique.Set import GHC.Types.Fixity.Env import GHC.Types.SourceFile import GHC.Unit.External import GHC.Unit.Finder import GHC.Unit.State import GHC.Unit.Home import GHC.Unit.Module import GHC.Unit.Module.ModIface import GHC.Unit.Module.ModSummary import GHC.Unit.Module.Warnings import GHC.Unit.Module.Deps import Control.Monad import Data.Function import Data.List (find, sortBy, sort) import qualified Data.Map as Map import qualified Data.Set as Set import Data.Word (Word64) --Qualified import so we can define a Semigroup instance -- but it doesn't clash with Outputable.<> import qualified Data.Semigroup {- ----------------------------------------------- Recompilation checking ----------------------------------------------- A complete description of how recompilation checking works can be found in the wiki commentary: https://gitlab.haskell.org/ghc/ghc/wikis/commentary/compiler/recompilation-avoidance Please read the above page for a top-down description of how this all works. Notes below cover specific issues related to the implementation. Basic idea: * In the mi_usages information in an interface, we record the fingerprint of each free variable of the module * In mkIface, we compute the fingerprint of each exported thing A.f. For each external thing that A.f refers to, we include the fingerprint of the external reference when computing the fingerprint of A.f. So if anything that A.f depends on changes, then A.f's fingerprint will change. Also record any dependent files added with * addDependentFile * #include * -optP-include * In checkOldIface we compare the mi_usages for the module with the actual fingerprint for all each thing recorded in mi_usages -} data RecompileRequired = UpToDate -- ^ everything is up to date, recompilation is not required | MustCompile -- ^ The .hs file has been touched, or the .o/.hi file does not exist | RecompBecause String -- ^ The .o/.hi files are up to date, but something else has changed -- to force recompilation; the String says what (one-line summary) deriving Eq instance Semigroup RecompileRequired where UpToDate <> r = r mc <> _ = mc instance Monoid RecompileRequired where mempty = UpToDate recompileRequired :: RecompileRequired -> Bool recompileRequired UpToDate = False recompileRequired _ = True -- | Top level function to check if the version of an old interface file -- is equivalent to the current source file the user asked us to compile. -- If the same, we can avoid recompilation. We return a tuple where the -- first element is a bool saying if we should recompile the object file -- and the second is maybe the interface file, where Nothing means to -- rebuild the interface file and not use the existing one. checkOldIface :: HscEnv -> ModSummary -> SourceModified -> Maybe ModIface -- Old interface from compilation manager, if any -> IO (RecompileRequired, Maybe ModIface) checkOldIface hsc_env mod_summary source_modified maybe_iface = do let dflags = hsc_dflags hsc_env let logger = hsc_logger hsc_env showPass logger dflags $ "Checking old interface for " ++ (showPpr dflags $ ms_mod mod_summary) ++ " (use -ddump-hi-diffs for more details)" initIfaceCheck (text "checkOldIface") hsc_env $ check_old_iface hsc_env mod_summary source_modified maybe_iface check_old_iface :: HscEnv -> ModSummary -> SourceModified -> Maybe ModIface -> IfG (RecompileRequired, Maybe ModIface) check_old_iface hsc_env mod_summary src_modified maybe_iface = let dflags = hsc_dflags hsc_env getIface = case maybe_iface of Just _ -> do traceIf (text "We already have the old interface for" <+> ppr (ms_mod mod_summary)) return maybe_iface Nothing -> loadIface loadIface = do let iface_path = msHiFilePath mod_summary read_result <- readIface (ms_mod mod_summary) iface_path case read_result of Failed err -> do traceIf (text "FYI: cannot read old interface file:" $$ nest 4 err) traceHiDiffs (text "Old interface file was invalid:" $$ nest 4 err) return Nothing Succeeded iface -> do traceIf (text "Read the interface file" <+> text iface_path) return $ Just iface src_changed | gopt Opt_ForceRecomp (hsc_dflags hsc_env) = True | SourceModified <- src_modified = True | otherwise = False in do when src_changed $ traceHiDiffs (nest 4 $ text "Source file changed or recompilation check turned off") case src_changed of -- If the source has changed and we're in interactive mode, -- avoid reading an interface; just return the one we might -- have been supplied with. True | not (backendProducesObject $ backend dflags) -> return (MustCompile, maybe_iface) -- Try and read the old interface for the current module -- from the .hi file left from the last time we compiled it True -> do maybe_iface' <- getIface return (MustCompile, maybe_iface') False -> do maybe_iface' <- getIface case maybe_iface' of -- We can't retrieve the iface Nothing -> return (MustCompile, Nothing) -- We have got the old iface; check its versions -- even in the SourceUnmodifiedAndStable case we -- should check versions because some packages -- might have changed or gone away. Just iface -> checkVersions hsc_env mod_summary iface -- | Check if a module is still the same 'version'. -- -- This function is called in the recompilation checker after we have -- determined that the module M being checked hasn't had any changes -- to its source file since we last compiled M. So at this point in general -- two things may have changed that mean we should recompile M: -- * The interface export by a dependency of M has changed. -- * The compiler flags specified this time for M have changed -- in a manner that is significant for recompilation. -- We return not just if we should recompile the object file but also -- if we should rebuild the interface file. checkVersions :: HscEnv -> ModSummary -> ModIface -- Old interface -> IfG (RecompileRequired, Maybe ModIface) checkVersions hsc_env mod_summary iface = do { traceHiDiffs (text "Considering whether compilation is required for" <+> ppr (mi_module iface) <> colon) -- readIface will have verified that the UnitId matches, -- but we ALSO must make sure the instantiation matches up. See -- test case bkpcabal04! ; if not (isHomeModule home_unit (mi_module iface)) then return (RecompBecause "-this-unit-id changed", Nothing) else do { ; recomp <- checkFlagHash hsc_env iface ; if recompileRequired recomp then return (recomp, Nothing) else do { ; recomp <- checkOptimHash hsc_env iface ; if recompileRequired recomp then return (recomp, Nothing) else do { ; recomp <- checkHpcHash hsc_env iface ; if recompileRequired recomp then return (recomp, Nothing) else do { ; recomp <- checkMergedSignatures mod_summary iface ; if recompileRequired recomp then return (recomp, Nothing) else do { ; recomp <- checkHsig mod_summary iface ; if recompileRequired recomp then return (recomp, Nothing) else do { ; recomp <- checkHie mod_summary ; if recompileRequired recomp then return (recomp, Nothing) else do { ; recomp <- checkDependencies hsc_env mod_summary iface ; if recompileRequired recomp then return (recomp, Just iface) else do { ; recomp <- checkPlugins hsc_env iface ; if recompileRequired recomp then return (recomp, Nothing) else do { -- Source code unchanged and no errors yet... carry on -- -- First put the dependent-module info, read from the old -- interface, into the envt, so that when we look for -- interfaces we look for the right one (.hi or .hi-boot) -- -- It's just temporary because either the usage check will succeed -- (in which case we are done with this module) or it'll fail (in which -- case we'll compile the module from scratch anyhow). -- -- We do this regardless of compilation mode, although in --make mode -- all the dependent modules should be in the HPT already, so it's -- quite redundant ; updateEps_ $ \eps -> eps { eps_is_boot = mod_deps } ; recomp <- checkList [checkModUsage (homeUnitAsUnit home_unit) u | u <- mi_usages iface] ; return (recomp, Just iface) }}}}}}}}}} where home_unit = hsc_home_unit hsc_env -- This is a bit of a hack really mod_deps :: ModuleNameEnv ModuleNameWithIsBoot mod_deps = mkModDeps (dep_mods (mi_deps iface)) -- | Check if any plugins are requesting recompilation checkPlugins :: HscEnv -> ModIface -> IfG RecompileRequired checkPlugins hsc_env iface = liftIO $ do new_fingerprint <- fingerprintPlugins hsc_env let old_fingerprint = mi_plugin_hash (mi_final_exts iface) pr <- mconcat <$> mapM pluginRecompile' (plugins hsc_env) return $ pluginRecompileToRecompileRequired old_fingerprint new_fingerprint pr fingerprintPlugins :: HscEnv -> IO Fingerprint fingerprintPlugins hsc_env = fingerprintPlugins' $ plugins hsc_env fingerprintPlugins' :: [PluginWithArgs] -> IO Fingerprint fingerprintPlugins' plugins = do res <- mconcat <$> mapM pluginRecompile' plugins return $ case res of NoForceRecompile -> fingerprintString "NoForceRecompile" ForceRecompile -> fingerprintString "ForceRecompile" -- is the chance of collision worth worrying about? -- An alternative is to fingerprintFingerprints [fingerprintString -- "maybeRecompile", fp] (MaybeRecompile fp) -> fp pluginRecompileToRecompileRequired :: Fingerprint -> Fingerprint -> PluginRecompile -> RecompileRequired pluginRecompileToRecompileRequired old_fp new_fp pr | old_fp == new_fp = case pr of NoForceRecompile -> UpToDate -- we already checked the fingerprint above so a mismatch is not possible -- here, remember that: `fingerprint (MaybeRecomp x) == x`. MaybeRecompile _ -> UpToDate -- when we have an impure plugin in the stack we have to unconditionally -- recompile since it might integrate all sorts of crazy IO results into -- its compilation output. ForceRecompile -> RecompBecause "Impure plugin forced recompilation" | old_fp `elem` magic_fingerprints || new_fp `elem` magic_fingerprints -- The fingerprints do not match either the old or new one is a magic -- fingerprint. This happens when non-pure plugins are added for the first -- time or when we go from one recompilation strategy to another: (force -> -- no-force, maybe-recomp -> no-force, no-force -> maybe-recomp etc.) -- -- For example when we go from ForceRecomp to NoForceRecomp -- recompilation is triggered since the old impure plugins could have -- changed the build output which is now back to normal. = RecompBecause "Plugins changed" | otherwise = let reason = "Plugin fingerprint changed" in case pr of -- even though a plugin is forcing recompilation the fingerprint changed -- which would cause recompilation anyways so we report the fingerprint -- change instead. ForceRecompile -> RecompBecause reason _ -> RecompBecause reason where magic_fingerprints = [ fingerprintString "NoForceRecompile" , fingerprintString "ForceRecompile" ] -- | Check if an hsig file needs recompilation because its -- implementing module has changed. checkHsig :: ModSummary -> ModIface -> IfG RecompileRequired checkHsig mod_summary iface = do hsc_env <- getTopEnv let home_unit = hsc_home_unit hsc_env outer_mod = ms_mod mod_summary inner_mod = homeModuleNameInstantiation home_unit (moduleName outer_mod) MASSERT( isHomeModule home_unit outer_mod ) case inner_mod == mi_semantic_module iface of True -> up_to_date (text "implementing module unchanged") False -> return (RecompBecause "implementing module changed") -- | Check if @.hie@ file is out of date or missing. checkHie :: ModSummary -> IfG RecompileRequired checkHie mod_summary = do dflags <- getDynFlags let hie_date_opt = ms_hie_date mod_summary hs_date = ms_hs_date mod_summary pure $ case gopt Opt_WriteHie dflags of False -> UpToDate True -> case hie_date_opt of Nothing -> RecompBecause "HIE file is missing" Just hie_date | hie_date < hs_date -> RecompBecause "HIE file is out of date" | otherwise -> UpToDate -- | Check the flags haven't changed checkFlagHash :: HscEnv -> ModIface -> IfG RecompileRequired checkFlagHash hsc_env iface = do let old_hash = mi_flag_hash (mi_final_exts iface) new_hash <- liftIO $ fingerprintDynFlags hsc_env (mi_module iface) putNameLiterally case old_hash == new_hash of True -> up_to_date (text "Module flags unchanged") False -> out_of_date_hash "flags changed" (text " Module flags have changed") old_hash new_hash -- | Check the optimisation flags haven't changed checkOptimHash :: HscEnv -> ModIface -> IfG RecompileRequired checkOptimHash hsc_env iface = do let old_hash = mi_opt_hash (mi_final_exts iface) new_hash <- liftIO $ fingerprintOptFlags (hsc_dflags hsc_env) putNameLiterally if | old_hash == new_hash -> up_to_date (text "Optimisation flags unchanged") | gopt Opt_IgnoreOptimChanges (hsc_dflags hsc_env) -> up_to_date (text "Optimisation flags changed; ignoring") | otherwise -> out_of_date_hash "Optimisation flags changed" (text " Optimisation flags have changed") old_hash new_hash -- | Check the HPC flags haven't changed checkHpcHash :: HscEnv -> ModIface -> IfG RecompileRequired checkHpcHash hsc_env iface = do let old_hash = mi_hpc_hash (mi_final_exts iface) new_hash <- liftIO $ fingerprintHpcFlags (hsc_dflags hsc_env) putNameLiterally if | old_hash == new_hash -> up_to_date (text "HPC flags unchanged") | gopt Opt_IgnoreHpcChanges (hsc_dflags hsc_env) -> up_to_date (text "HPC flags changed; ignoring") | otherwise -> out_of_date_hash "HPC flags changed" (text " HPC flags have changed") old_hash new_hash -- Check that the set of signatures we are merging in match. -- If the -unit-id flags change, this can change too. checkMergedSignatures :: ModSummary -> ModIface -> IfG RecompileRequired checkMergedSignatures mod_summary iface = do unit_state <- hsc_units <$> getTopEnv let old_merged = sort [ mod | UsageMergedRequirement{ usg_mod = mod } <- mi_usages iface ] new_merged = case Map.lookup (ms_mod_name mod_summary) (requirementContext unit_state) of Nothing -> [] Just r -> sort $ map (instModuleToModule unit_state) r if old_merged == new_merged then up_to_date (text "signatures to merge in unchanged" $$ ppr new_merged) else return (RecompBecause "signatures to merge in changed") -- If the direct imports of this module are resolved to targets that -- are not among the dependencies of the previous interface file, -- then we definitely need to recompile. This catches cases like -- - an exposed package has been upgraded -- - we are compiling with different package flags -- - a home module that was shadowing a package module has been removed -- - a new home module has been added that shadows a package module -- See bug #1372. -- -- In addition, we also check if the union of dependencies of the imported -- modules has any difference to the previous set of dependencies. We would need -- to recompile in that case also since the `mi_deps` field of ModIface needs -- to be updated to match that information. This is one of the invariants -- of interface files (see https://gitlab.haskell.org/ghc/ghc/wikis/commentary/compiler/recompilation-avoidance#interface-file-invariants). -- See bug #16511. -- -- Returns (RecompBecause ) if recompilation is required. checkDependencies :: HscEnv -> ModSummary -> ModIface -> IfG RecompileRequired checkDependencies hsc_env summary iface = checkList $ [ checkList (map dep_missing (ms_imps summary ++ ms_srcimps summary)) , do (recomp, mnames_seen) <- runUntilRecompRequired $ map checkForNewHomeDependency (ms_home_imps summary) case recomp of UpToDate -> do let seen_home_deps = Set.unions $ map Set.fromList mnames_seen checkIfAllOldHomeDependenciesAreSeen seen_home_deps _ -> return recomp] where prev_dep_mods = dep_mods (mi_deps iface) prev_dep_plgn = dep_plgins (mi_deps iface) prev_dep_pkgs = dep_pkgs (mi_deps iface) home_unit = hsc_home_unit hsc_env dep_missing (mb_pkg, L _ mod) = do find_res <- liftIO $ findImportedModule hsc_env mod (mb_pkg) let reason = moduleNameString mod ++ " changed" case find_res of Found _ mod | isHomeUnit home_unit pkg -> if moduleName mod `notElem` map gwib_mod prev_dep_mods ++ prev_dep_plgn then do traceHiDiffs $ text "imported module " <> quotes (ppr mod) <> text " not among previous dependencies" return (RecompBecause reason) else return UpToDate | otherwise -> if toUnitId pkg `notElem` (map fst prev_dep_pkgs) then do traceHiDiffs $ text "imported module " <> quotes (ppr mod) <> text " is from package " <> quotes (ppr pkg) <> text ", which is not among previous dependencies" return (RecompBecause reason) else return UpToDate where pkg = moduleUnit mod _otherwise -> return (RecompBecause reason) projectNonBootNames = map gwib_mod . filter ((== NotBoot) . gwib_isBoot) old_deps = Set.fromList $ projectNonBootNames prev_dep_mods isOldHomeDeps = flip Set.member old_deps checkForNewHomeDependency (L _ mname) = do let mod = mkHomeModule home_unit mname str_mname = moduleNameString mname reason = str_mname ++ " changed" -- We only want to look at home modules to check if any new home dependency -- pops in and thus here, skip modules that are not home. Checking -- membership in old home dependencies suffice because the `dep_missing` -- check already verified that all imported home modules are present there. if not (isOldHomeDeps mname) then return (UpToDate, []) else do mb_result <- getFromModIface "need mi_deps for" mod $ \imported_iface -> do let mnames = mname:(map gwib_mod $ filter ((== NotBoot) . gwib_isBoot) $ dep_mods $ mi_deps imported_iface) case find (not . isOldHomeDeps) mnames of Nothing -> return (UpToDate, mnames) Just new_dep_mname -> do traceHiDiffs $ text "imported home module " <> quotes (ppr mod) <> text " has a new dependency " <> quotes (ppr new_dep_mname) return (RecompBecause reason, []) return $ fromMaybe (MustCompile, []) mb_result -- Performs all recompilation checks in the list until a check that yields -- recompile required is encountered. Returns the list of the results of -- all UpToDate checks. runUntilRecompRequired [] = return (UpToDate, []) runUntilRecompRequired (check:checks) = do (recompile, value) <- check if recompileRequired recompile then return (recompile, []) else do (recomp, values) <- runUntilRecompRequired checks return (recomp, value:values) checkIfAllOldHomeDependenciesAreSeen seen_deps = do let unseen_old_deps = Set.difference old_deps seen_deps if not (null unseen_old_deps) then do let missing_dep = Set.elemAt 0 unseen_old_deps traceHiDiffs $ text "missing old home dependency " <> quotes (ppr missing_dep) return $ RecompBecause "missing old dependency" else return UpToDate needInterface :: Module -> (ModIface -> IfG RecompileRequired) -> IfG RecompileRequired needInterface mod continue = do mb_recomp <- getFromModIface "need version info for" mod continue case mb_recomp of Nothing -> return MustCompile Just recomp -> return recomp getFromModIface :: String -> Module -> (ModIface -> IfG a) -> IfG (Maybe a) getFromModIface doc_msg mod getter = do -- Load the imported interface if possible let doc_str = sep [text doc_msg, ppr mod] traceHiDiffs (text "Checking innterface for module" <+> ppr mod) mb_iface <- loadInterface doc_str mod ImportBySystem -- Load the interface, but don't complain on failure; -- Instead, get an Either back which we can test case mb_iface of Failed _ -> do traceHiDiffs (sep [text "Couldn't load interface for module", ppr mod]) return Nothing -- 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 Succeeded iface -> Just <$> getter iface -- | 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 :: Unit -> Usage -> IfG RecompileRequired checkModUsage _this_pkg UsagePackageModule{ usg_mod = mod, usg_mod_hash = old_mod_hash } = needInterface mod $ \iface -> do let reason = moduleNameString (moduleName mod) ++ " changed" checkModuleFingerprint reason old_mod_hash (mi_mod_hash (mi_final_exts iface)) -- We only track the ABI hash of package modules, rather than -- individual entity usages, so if the ABI hash changes we must -- recompile. This is safe but may entail more recompilation when -- a dependent package has changed. checkModUsage _ UsageMergedRequirement{ usg_mod = mod, usg_mod_hash = old_mod_hash } = needInterface mod $ \iface -> do let reason = moduleNameString (moduleName mod) ++ " changed (raw)" checkModuleFingerprint reason old_mod_hash (mi_mod_hash (mi_final_exts iface)) checkModUsage this_pkg UsageHomeModule{ usg_mod_name = mod_name, usg_mod_hash = old_mod_hash, usg_exports = maybe_old_export_hash, usg_entities = old_decl_hash } = do let mod = mkModule this_pkg mod_name needInterface mod $ \iface -> do let new_mod_hash = mi_mod_hash (mi_final_exts iface) new_decl_hash = mi_hash_fn (mi_final_exts iface) new_export_hash = mi_exp_hash (mi_final_exts iface) reason = moduleNameString mod_name ++ " changed" -- CHECK MODULE recompile <- checkModuleFingerprint reason old_mod_hash new_mod_hash if not (recompileRequired recompile) then return UpToDate else -- CHECK EXPORT LIST checkMaybeHash reason maybe_old_export_hash new_export_hash (text " Export list changed") $ do -- CHECK ITEMS ONE BY ONE recompile <- checkList [ checkEntityUsage reason new_decl_hash u | u <- old_decl_hash] if recompileRequired recompile then return recompile -- This one failed, so just bail out now else up_to_date (text " Great! The bits I use are up to date") checkModUsage _this_pkg UsageFile{ usg_file_path = file, usg_file_hash = old_hash } = liftIO $ handleIO handler $ do new_hash <- getFileHash file if (old_hash /= new_hash) then return recomp else return UpToDate where recomp = RecompBecause (file ++ " changed") handler = #if defined(DEBUG) \e -> pprTrace "UsageFile" (text (show e)) $ return recomp #else \_ -> return recomp -- if we can't find the file, just recompile, don't fail #endif ------------------------ checkModuleFingerprint :: String -> Fingerprint -> Fingerprint -> IfG RecompileRequired checkModuleFingerprint reason old_mod_hash new_mod_hash | new_mod_hash == old_mod_hash = up_to_date (text "Module fingerprint unchanged") | otherwise = out_of_date_hash reason (text " Module fingerprint has changed") old_mod_hash new_mod_hash ------------------------ checkMaybeHash :: String -> Maybe Fingerprint -> Fingerprint -> SDoc -> IfG RecompileRequired -> IfG RecompileRequired checkMaybeHash reason maybe_old_hash new_hash doc continue | Just hash <- maybe_old_hash, hash /= new_hash = out_of_date_hash reason doc hash new_hash | otherwise = continue ------------------------ checkEntityUsage :: String -> (OccName -> Maybe (OccName, Fingerprint)) -> (OccName, Fingerprint) -> IfG RecompileRequired checkEntityUsage reason new_hash (name,old_hash) = case new_hash name of Nothing -> -- We used it before, but it ain't there now out_of_date reason (sep [text "No longer exported:", ppr name]) Just (_, new_hash) -- It's there, but is it up to date? | new_hash == old_hash -> do traceHiDiffs (text " Up to date" <+> ppr name <+> parens (ppr new_hash)) return UpToDate | otherwise -> out_of_date_hash reason (text " Out of date:" <+> ppr name) old_hash new_hash up_to_date :: SDoc -> IfG RecompileRequired up_to_date msg = traceHiDiffs msg >> return UpToDate out_of_date :: String -> SDoc -> IfG RecompileRequired out_of_date reason msg = traceHiDiffs msg >> return (RecompBecause reason) out_of_date_hash :: String -> SDoc -> Fingerprint -> Fingerprint -> IfG RecompileRequired out_of_date_hash reason msg old_hash new_hash = out_of_date reason (hsep [msg, ppr old_hash, text "->", ppr new_hash]) ---------------------- checkList :: [IfG RecompileRequired] -> IfG RecompileRequired -- This helper is used in two places checkList [] = return UpToDate checkList (check:checks) = do recompile <- check if recompileRequired recompile then return recompile else checkList checks -- --------------------------------------------------------------------------- -- Compute fingerprints for the interface {- Note [Fingerprinting IfaceDecls] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The general idea here is that we first examine the 'IfaceDecl's and determine the recursive groups of them. We then walk these groups in dependency order, serializing each contained 'IfaceDecl' to a "Binary" buffer which we then hash using MD5 to produce a fingerprint for the group. However, the serialization that we use is a bit funny: we override the @putName@ operation with our own which serializes the hash of a 'Name' instead of the 'Name' itself. This ensures that the fingerprint of a decl changes if anything in its transitive closure changes. This trick is why we must be careful about traversing in dependency order: we need to ensure that we have hashes for everything referenced by the decl which we are fingerprinting. Moreover, we need to be careful to distinguish between serialization of binding Names (e.g. the ifName field of a IfaceDecl) and non-binding (e.g. the ifInstCls field of a IfaceClsInst): only in the non-binding case should we include the fingerprint; in the binding case we shouldn't since it is merely the name of the thing that we are currently fingerprinting. Note [Fingerprinting recursive groups] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The fingerprinting of a single recursive group is a rather subtle affair, as seen in #18733. How not to fingerprint ---------------------- Prior to fixing #18733 we used the following (flawed) scheme to fingerprint a group in hash environment `hash_env0`: 1. extend hash_env0, giving each declaration in the group the fingerprint 0 2. use this environment to hash the declarations' ABIs, resulting in group_fingerprint 3. produce the final hash environment by extending hash_env0, mapping each declaration of the group to group_fingerprint However, this is wrong. Consider, for instance, a program like: data A = ARecu B | ABase String deriving (Show) data B = BRecu A | BBase Int deriving (Show) info :: B info = BBase 1 A consequence of (3) is that A and B will have the same fingerprint. This means that if the user changes `info` to: info :: A info = ABase "hello" The program's ABI fingerprint will not change despite `info`'s type, and therefore ABI, being clearly different. However, the incorrectness doesn't end there: (1) means that all recursive occurrences of names within the group will be given the same fingerprint. This means that the group's fingerprint won't change if we change an occurrence of A to B. Surprisingly, this bug (#18733) lurked for many years before being uncovered. How we now fingerprint ---------------------- As seen above, the fingerprinting function must ensure that a groups fingerprint captures the structure of within-group occurrences. The scheme that we use is: 0. To ensure determinism, sort the declarations into a stable order by declaration name 1. Extend hash_env0, giving each declaration in the group a sequential fingerprint (e.g. 0, 1, 2, ...). 2. Use this environment to hash the declarations' ABIs, resulting in group_fingerprint. Since we included the sequence number in step (1) programs identical up to transposition of recursive occurrences are distinguisable, avoiding the second issue mentioned above. 3. Produce the final environment by extending hash_env, mapping each declaration of the group to the hash of (group_fingerprint, i), where i is the position of the declaration in the stable ordering. Including i in the hash ensures that the first issue noted above is avoided. -} -- | Add fingerprints for top-level declarations to a 'ModIface'. -- -- See Note [Fingerprinting IfaceDecls] addFingerprints :: HscEnv -> PartialModIface -> IO ModIface addFingerprints hsc_env iface0 = do eps <- hscEPS hsc_env let decls = mi_decls iface0 warn_fn = mkIfaceWarnCache (mi_warns iface0) fix_fn = mkIfaceFixCache (mi_fixities iface0) -- The ABI of a declaration represents everything that is made -- visible about the declaration that a client can depend on. -- see IfaceDeclABI below. declABI :: IfaceDecl -> IfaceDeclABI -- TODO: I'm not sure if this should be semantic_mod or this_mod. -- See also Note [Identity versus semantic module] declABI decl = (this_mod, decl, extras) where extras = declExtras fix_fn ann_fn non_orph_rules non_orph_insts non_orph_fis top_lvl_name_env decl -- This is used for looking up the Name of a default method -- from its OccName. See Note [default method Name] top_lvl_name_env = mkOccEnv [ (nameOccName nm, nm) | IfaceId { ifName = nm } <- decls ] -- Dependency edges between declarations in the current module. -- This is computed by finding the free external names of each -- declaration, including IfaceDeclExtras (things that a -- declaration implicitly depends on). edges :: [ Node Unique IfaceDeclABI ] edges = [ DigraphNode abi (getUnique (getOccName decl)) out | decl <- decls , let abi = declABI decl , let out = localOccs $ freeNamesDeclABI abi ] name_module n = ASSERT2( isExternalName n, ppr n ) nameModule n localOccs = map (getUnique . getParent . getOccName) -- NB: names always use semantic module, so -- filtering must be on the semantic module! -- See Note [Identity versus semantic module] . filter ((== semantic_mod) . name_module) . nonDetEltsUniqSet -- It's OK to use nonDetEltsUFM as localOccs is only -- used to construct the edges and -- stronglyConnCompFromEdgedVertices is deterministic -- even with non-deterministic order of edges as -- explained in Note [Deterministic SCC] in GHC.Data.Graph.Directed. where getParent :: OccName -> OccName getParent occ = lookupOccEnv parent_map occ `orElse` occ -- maps OccNames to their parents in the current module. -- e.g. a reference to a constructor must be turned into a reference -- to the TyCon for the purposes of calculating dependencies. parent_map :: OccEnv OccName parent_map = foldl' extend emptyOccEnv decls where extend env d = extendOccEnvList env [ (b,n) | b <- ifaceDeclImplicitBndrs d ] where n = getOccName d -- Strongly-connected groups of declarations, in dependency order groups :: [SCC IfaceDeclABI] groups = stronglyConnCompFromEdgedVerticesUniq edges global_hash_fn = mkHashFun hsc_env eps -- How to output Names when generating the data to fingerprint. -- Here we want to output the fingerprint for each top-level -- Name, whether it comes from the current module or another -- module. In this way, the fingerprint for a declaration will -- change if the fingerprint for anything it refers to (transitively) -- changes. mk_put_name :: OccEnv (OccName,Fingerprint) -> BinHandle -> Name -> IO () mk_put_name local_env bh name | isWiredInName name = putNameLiterally bh name -- wired-in names don't have fingerprints | otherwise = ASSERT2( isExternalName name, ppr name ) let hash | nameModule name /= semantic_mod = global_hash_fn name -- Get it from the REAL interface!! -- This will trigger when we compile an hsig file -- and we know a backing impl for it. -- See Note [Identity versus semantic module] | semantic_mod /= this_mod , not (isHoleModule semantic_mod) = global_hash_fn name | otherwise = return (snd (lookupOccEnv local_env (getOccName name) `orElse` pprPanic "urk! lookup local fingerprint" (ppr name $$ ppr local_env))) -- This panic indicates that we got the dependency -- analysis wrong, because we needed a fingerprint for -- an entity that wasn't in the environment. To debug -- it, turn the panic into a trace, uncomment the -- pprTraces below, run the compile again, and inspect -- the output and the generated .hi file with -- --show-iface. in hash >>= put_ bh -- take a strongly-connected group of declarations and compute -- its fingerprint. fingerprint_group :: (OccEnv (OccName,Fingerprint), [(Fingerprint,IfaceDecl)]) -> SCC IfaceDeclABI -> IO (OccEnv (OccName,Fingerprint), [(Fingerprint,IfaceDecl)]) fingerprint_group (local_env, decls_w_hashes) (AcyclicSCC abi) = do let hash_fn = mk_put_name local_env decl = abiDecl abi --pprTrace "fingerprinting" (ppr (ifName decl) ) $ do hash <- computeFingerprint hash_fn abi env' <- extend_hash_env local_env (hash,decl) return (env', (hash,decl) : decls_w_hashes) fingerprint_group (local_env, decls_w_hashes) (CyclicSCC abis) = do let stable_abis = sortBy cmp_abiNames abis stable_decls = map abiDecl stable_abis local_env1 <- foldM extend_hash_env local_env (zip (map mkRecFingerprint [0..]) stable_decls) -- See Note [Fingerprinting recursive groups] let hash_fn = mk_put_name local_env1 -- pprTrace "fingerprinting" (ppr (map ifName decls) ) $ do -- put the cycle in a canonical order hash <- computeFingerprint hash_fn stable_abis let pairs = zip (map (bumpFingerprint hash) [0..]) stable_decls -- See Note [Fingerprinting recursive groups] local_env2 <- foldM extend_hash_env local_env pairs return (local_env2, pairs ++ decls_w_hashes) -- Make a fingerprint from the ordinal position of a binding in its group. mkRecFingerprint :: Word64 -> Fingerprint mkRecFingerprint i = Fingerprint 0 i bumpFingerprint :: Fingerprint -> Word64 -> Fingerprint bumpFingerprint fp n = fingerprintFingerprints [ fp, mkRecFingerprint n ] -- we have fingerprinted the whole declaration, but we now need -- to assign fingerprints to all the OccNames that it binds, to -- use when referencing those OccNames in later declarations. -- extend_hash_env :: OccEnv (OccName,Fingerprint) -> (Fingerprint,IfaceDecl) -> IO (OccEnv (OccName,Fingerprint)) extend_hash_env env0 (hash,d) = return (foldr (\(b,fp) env -> extendOccEnv env b (b,fp)) env0 (ifaceDeclFingerprints hash d)) -- (local_env, decls_w_hashes) <- foldM fingerprint_group (emptyOccEnv, []) groups -- when calculating fingerprints, we always need to use canonical -- ordering for lists of things. In particular, the mi_deps has various -- lists of modules and suchlike, so put these all in canonical order: let sorted_deps :: Dependencies sorted_deps = sortDependencies (mi_deps iface0) -- The export hash of a module depends on the orphan hashes of the -- orphan modules below us in the dependency tree. This is the way -- that changes in orphans get propagated all the way up the -- dependency tree. -- -- Note [A bad dep_orphs optimization] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- In a previous version of this code, we filtered out orphan modules which -- were not from the home package, justifying it by saying that "we'd -- pick up the ABI hashes of the external module instead". This is wrong. -- Suppose that we have: -- -- module External where -- instance Show (a -> b) -- -- module Home1 where -- import External -- -- module Home2 where -- import Home1 -- -- The export hash of Home1 needs to reflect the orphan instances of -- External. It's true that Home1 will get rebuilt if the orphans -- of External, but we also need to make sure Home2 gets rebuilt -- as well. See #12733 for more details. let orph_mods = filter (/= this_mod) -- Note [Do not update EPS with your own hi-boot] $ dep_orphs sorted_deps dep_orphan_hashes <- getOrphanHashes hsc_env orph_mods -- Note [Do not update EPS with your own hi-boot] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- (See also #10182). When your hs-boot file includes an orphan -- instance declaration, you may find that the dep_orphs of a module you -- import contains reference to yourself. DO NOT actually load this module -- or add it to the orphan hashes: you're going to provide the orphan -- instances yourself, no need to consult hs-boot; if you do load the -- interface into EPS, you will see a duplicate orphan instance. orphan_hash <- computeFingerprint (mk_put_name local_env) (map ifDFun orph_insts, orph_rules, orph_fis) -- the export list hash doesn't depend on the fingerprints of -- the Names it mentions, only the Names themselves, hence putNameLiterally. export_hash <- computeFingerprint putNameLiterally (mi_exports iface0, orphan_hash, dep_orphan_hashes, dep_pkgs (mi_deps iface0), -- See Note [Export hash depends on non-orphan family instances] dep_finsts (mi_deps iface0), -- dep_pkgs: see "Package Version Changes" on -- wiki/commentary/compiler/recompilation-avoidance mi_trust iface0) -- Make sure change of Safe Haskell mode causes recomp. -- Note [Export hash depends on non-orphan family instances] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- -- Suppose we have: -- -- module A where -- type instance F Int = Bool -- -- module B where -- import A -- -- module C where -- import B -- -- The family instance consistency check for C depends on the dep_finsts of -- B. If we rename module A to A2, when the dep_finsts of B changes, we need -- to make sure that C gets rebuilt. Effectively, the dep_finsts are part of -- the exports of B, because C always considers them when checking -- consistency. -- -- A full discussion is in #12723. -- -- We do NOT need to hash dep_orphs, because this is implied by -- dep_orphan_hashes, and we do not need to hash ordinary class instances, -- because there is no eager consistency check as there is with type families -- (also we didn't store it anywhere!) -- -- put the declarations in a canonical order, sorted by OccName let sorted_decls :: [(Fingerprint, IfaceDecl)] sorted_decls = Map.elems $ Map.fromList $ [(getOccName d, e) | e@(_, d) <- decls_w_hashes] -- the flag hash depends on: -- - (some of) dflags -- it returns two hashes, one that shouldn't change -- the abi hash and one that should flag_hash <- fingerprintDynFlags hsc_env this_mod putNameLiterally opt_hash <- fingerprintOptFlags dflags putNameLiterally hpc_hash <- fingerprintHpcFlags dflags putNameLiterally plugin_hash <- fingerprintPlugins hsc_env -- the ABI hash depends on: -- - decls -- - export list -- - orphans -- - deprecations -- - flag abi hash mod_hash <- computeFingerprint putNameLiterally (map fst sorted_decls, export_hash, -- includes orphan_hash mi_warns iface0) -- The interface hash depends on: -- - the ABI hash, plus -- - the module level annotations, -- - usages -- - deps (home and external packages, dependent files) -- - hpc iface_hash <- computeFingerprint putNameLiterally (mod_hash, ann_fn (mkVarOcc "module"), -- See mkIfaceAnnCache mi_usages iface0, sorted_deps, mi_hpc iface0) let final_iface_exts = ModIfaceBackend { mi_iface_hash = iface_hash , mi_mod_hash = mod_hash , mi_flag_hash = flag_hash , mi_opt_hash = opt_hash , mi_hpc_hash = hpc_hash , mi_plugin_hash = plugin_hash , mi_orphan = not ( all ifRuleAuto orph_rules -- See Note [Orphans and auto-generated rules] && null orph_insts && null orph_fis) , mi_finsts = not (null (mi_fam_insts iface0)) , mi_exp_hash = export_hash , mi_orphan_hash = orphan_hash , mi_warn_fn = warn_fn , mi_fix_fn = fix_fn , mi_hash_fn = lookupOccEnv local_env } final_iface = iface0 { mi_decls = sorted_decls, mi_final_exts = final_iface_exts } -- return final_iface where this_mod = mi_module iface0 semantic_mod = mi_semantic_module iface0 dflags = hsc_dflags hsc_env (non_orph_insts, orph_insts) = mkOrphMap ifInstOrph (mi_insts iface0) (non_orph_rules, orph_rules) = mkOrphMap ifRuleOrph (mi_rules iface0) (non_orph_fis, orph_fis) = mkOrphMap ifFamInstOrph (mi_fam_insts iface0) ann_fn = mkIfaceAnnCache (mi_anns iface0) -- | Retrieve the orphan hashes 'mi_orphan_hash' for a list of modules -- (in particular, the orphan modules which are transitively imported by the -- current module). -- -- Q: Why do we need the hash at all, doesn't the list of transitively -- imported orphan modules suffice? -- -- A: If one of our transitive imports adds a new orphan instance, our -- export hash must change so that modules which import us rebuild. If we just -- hashed the [Module], the hash would not change even when a new instance was -- added to a module that already had an orphan instance. -- -- Q: Why don't we just hash the orphan hashes of our direct dependencies? -- Why the full transitive closure? -- -- A: Suppose we have these modules: -- -- module A where -- instance Show (a -> b) where -- module B where -- import A -- ** -- module C where -- import A -- import B -- -- Whether or not we add or remove the import to A in B affects the -- orphan hash of B. But it shouldn't really affect the orphan hash -- of C. If we hashed only direct dependencies, there would be no -- way to tell that the net effect was a wash, and we'd be forced -- to recompile C and everything else. getOrphanHashes :: HscEnv -> [Module] -> IO [Fingerprint] getOrphanHashes hsc_env mods = do eps <- hscEPS hsc_env let hpt = hsc_HPT hsc_env pit = eps_PIT eps get_orph_hash mod = case lookupIfaceByModule hpt pit mod of Just iface -> return (mi_orphan_hash (mi_final_exts iface)) Nothing -> do -- similar to 'mkHashFun' iface <- initIfaceLoad hsc_env . withException $ loadInterface (text "getOrphanHashes") mod ImportBySystem return (mi_orphan_hash (mi_final_exts iface)) -- mapM get_orph_hash mods sortDependencies :: Dependencies -> Dependencies sortDependencies d = Deps { dep_mods = sortBy (lexicalCompareFS `on` (moduleNameFS . gwib_mod)) (dep_mods d), dep_pkgs = sortBy (compare `on` fst) (dep_pkgs d), dep_orphs = sortBy stableModuleCmp (dep_orphs d), dep_finsts = sortBy stableModuleCmp (dep_finsts d), dep_plgins = sortBy (lexicalCompareFS `on` moduleNameFS) (dep_plgins d) } {- ************************************************************************ * * The ABI of an IfaceDecl * * ************************************************************************ Note [The ABI of an IfaceDecl] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ABI of a declaration consists of: (a) the full name of the identifier (inc. module and package, because these are used to construct the symbol name by which the identifier is known externally). (b) the declaration itself, as exposed to clients. That is, the definition of an Id is included in the fingerprint only if it is made available as an unfolding in the interface. (c) the fixity of the identifier (if it exists) (d) for Ids: rules (e) for classes: instances, fixity & rules for methods (f) for datatypes: instances, fixity & rules for constrs Items (c)-(f) are not stored in the IfaceDecl, but instead appear elsewhere in the interface file. But they are *fingerprinted* with the declaration itself. This is done by grouping (c)-(f) in IfaceDeclExtras, and fingerprinting that as part of the declaration. -} type IfaceDeclABI = (Module, IfaceDecl, IfaceDeclExtras) data IfaceDeclExtras = IfaceIdExtras IfaceIdExtras | IfaceDataExtras (Maybe Fixity) -- Fixity of the tycon itself (if it exists) [IfaceInstABI] -- Local class and family instances of this tycon -- See Note [Orphans] in GHC.Core.InstEnv [AnnPayload] -- Annotations of the type itself [IfaceIdExtras] -- For each constructor: fixity, RULES and annotations | IfaceClassExtras (Maybe Fixity) -- Fixity of the class itself (if it exists) [IfaceInstABI] -- Local instances of this class *or* -- of its associated data types -- See Note [Orphans] in GHC.Core.InstEnv [AnnPayload] -- Annotations of the type itself [IfaceIdExtras] -- For each class method: fixity, RULES and annotations [IfExtName] -- Default methods. If a module -- mentions a class, then it can -- instantiate the class and thereby -- use the default methods, so we must -- include these in the fingerprint of -- a class. | IfaceSynonymExtras (Maybe Fixity) [AnnPayload] | IfaceFamilyExtras (Maybe Fixity) [IfaceInstABI] [AnnPayload] | IfaceOtherDeclExtras data IfaceIdExtras = IdExtras (Maybe Fixity) -- Fixity of the Id (if it exists) [IfaceRule] -- Rules for the Id [AnnPayload] -- Annotations for the Id -- When hashing a class or family instance, we hash only the -- DFunId or CoAxiom, because that depends on all the -- information about the instance. -- type IfaceInstABI = IfExtName -- Name of DFunId or CoAxiom that is evidence for the instance abiDecl :: IfaceDeclABI -> IfaceDecl abiDecl (_, decl, _) = decl cmp_abiNames :: IfaceDeclABI -> IfaceDeclABI -> Ordering cmp_abiNames abi1 abi2 = getOccName (abiDecl abi1) `compare` getOccName (abiDecl abi2) freeNamesDeclABI :: IfaceDeclABI -> NameSet freeNamesDeclABI (_mod, decl, extras) = freeNamesIfDecl decl `unionNameSet` freeNamesDeclExtras extras freeNamesDeclExtras :: IfaceDeclExtras -> NameSet freeNamesDeclExtras (IfaceIdExtras id_extras) = freeNamesIdExtras id_extras freeNamesDeclExtras (IfaceDataExtras _ insts _ subs) = unionNameSets (mkNameSet insts : map freeNamesIdExtras subs) freeNamesDeclExtras (IfaceClassExtras _ insts _ subs defms) = unionNameSets $ mkNameSet insts : mkNameSet defms : map freeNamesIdExtras subs freeNamesDeclExtras (IfaceSynonymExtras _ _) = emptyNameSet freeNamesDeclExtras (IfaceFamilyExtras _ insts _) = mkNameSet insts freeNamesDeclExtras IfaceOtherDeclExtras = emptyNameSet freeNamesIdExtras :: IfaceIdExtras -> NameSet freeNamesIdExtras (IdExtras _ rules _) = unionNameSets (map freeNamesIfRule rules) instance Outputable IfaceDeclExtras where ppr IfaceOtherDeclExtras = Outputable.empty ppr (IfaceIdExtras extras) = ppr_id_extras extras ppr (IfaceSynonymExtras fix anns) = vcat [ppr fix, ppr anns] ppr (IfaceFamilyExtras fix finsts anns) = vcat [ppr fix, ppr finsts, ppr anns] ppr (IfaceDataExtras fix insts anns stuff) = vcat [ppr fix, ppr_insts insts, ppr anns, ppr_id_extras_s stuff] ppr (IfaceClassExtras fix insts anns stuff defms) = vcat [ppr fix, ppr_insts insts, ppr anns, ppr_id_extras_s stuff, ppr defms] ppr_insts :: [IfaceInstABI] -> SDoc ppr_insts _ = text "" ppr_id_extras_s :: [IfaceIdExtras] -> SDoc ppr_id_extras_s stuff = vcat (map ppr_id_extras stuff) ppr_id_extras :: IfaceIdExtras -> SDoc ppr_id_extras (IdExtras fix rules anns) = ppr fix $$ vcat (map ppr rules) $$ vcat (map ppr anns) -- This instance is used only to compute fingerprints instance Binary IfaceDeclExtras where get _bh = panic "no get for IfaceDeclExtras" put_ bh (IfaceIdExtras extras) = do putByte bh 1; put_ bh extras put_ bh (IfaceDataExtras fix insts anns cons) = do putByte bh 2; put_ bh fix; put_ bh insts; put_ bh anns; put_ bh cons put_ bh (IfaceClassExtras fix insts anns methods defms) = do putByte bh 3 put_ bh fix put_ bh insts put_ bh anns put_ bh methods put_ bh defms put_ bh (IfaceSynonymExtras fix anns) = do putByte bh 4; put_ bh fix; put_ bh anns put_ bh (IfaceFamilyExtras fix finsts anns) = do putByte bh 5; put_ bh fix; put_ bh finsts; put_ bh anns put_ bh IfaceOtherDeclExtras = putByte bh 6 instance Binary IfaceIdExtras where get _bh = panic "no get for IfaceIdExtras" put_ bh (IdExtras fix rules anns)= do { put_ bh fix; put_ bh rules; put_ bh anns } declExtras :: (OccName -> Maybe Fixity) -> (OccName -> [AnnPayload]) -> OccEnv [IfaceRule] -> OccEnv [IfaceClsInst] -> OccEnv [IfaceFamInst] -> OccEnv IfExtName -- lookup default method names -> IfaceDecl -> IfaceDeclExtras declExtras fix_fn ann_fn rule_env inst_env fi_env dm_env decl = case decl of IfaceId{} -> IfaceIdExtras (id_extras n) IfaceData{ifCons=cons} -> IfaceDataExtras (fix_fn n) (map ifFamInstAxiom (lookupOccEnvL fi_env n) ++ map ifDFun (lookupOccEnvL inst_env n)) (ann_fn n) (map (id_extras . occName . ifConName) (visibleIfConDecls cons)) IfaceClass{ifBody = IfConcreteClass { ifSigs=sigs, ifATs=ats }} -> IfaceClassExtras (fix_fn n) insts (ann_fn n) meths defms where insts = (map ifDFun $ (concatMap at_extras ats) ++ lookupOccEnvL inst_env n) -- Include instances of the associated types -- as well as instances of the class (#5147) meths = [id_extras (getOccName op) | IfaceClassOp op _ _ <- sigs] -- Names of all the default methods (see Note [default method Name]) defms = [ dmName | IfaceClassOp bndr _ (Just _) <- sigs , let dmOcc = mkDefaultMethodOcc (nameOccName bndr) , Just dmName <- [lookupOccEnv dm_env dmOcc] ] IfaceSynonym{} -> IfaceSynonymExtras (fix_fn n) (ann_fn n) IfaceFamily{} -> IfaceFamilyExtras (fix_fn n) (map ifFamInstAxiom (lookupOccEnvL fi_env n)) (ann_fn n) _other -> IfaceOtherDeclExtras where n = getOccName decl id_extras occ = IdExtras (fix_fn occ) (lookupOccEnvL rule_env occ) (ann_fn occ) at_extras (IfaceAT decl _) = lookupOccEnvL inst_env (getOccName decl) {- Note [default method Name] (see also #15970) The Names for the default methods aren't available in Iface syntax. * We originally start with a DefMethInfo from the class, contain a Name for the default method * We turn that into Iface syntax as a DefMethSpec which lacks a Name entirely. Why? Because the Name can be derived from the method name (in GHC.IfaceToCore), so doesn't need to be serialised into the interface file. But now we have to get the Name back, because the class declaration's fingerprint needs to depend on it (this was the bug in #15970). This is done in a slightly convoluted way: * Then, in addFingerprints we build a map that maps OccNames to Names * We pass that map to declExtras which laboriously looks up in the map (using the derived occurrence name) to recover the Name we have just thrown away. -} lookupOccEnvL :: OccEnv [v] -> OccName -> [v] lookupOccEnvL env k = lookupOccEnv env k `orElse` [] {- -- for testing: use the md5sum command to generate fingerprints and -- compare the results against our built-in version. fp' <- oldMD5 dflags bh if fp /= fp' then pprPanic "computeFingerprint" (ppr fp <+> ppr fp') else return fp oldMD5 dflags bh = do tmp <- newTempName dflags CurrentModule "bin" writeBinMem bh tmp tmp2 <- newTempName dflags CurrentModule "md5" let cmd = "md5sum " ++ tmp ++ " >" ++ tmp2 r <- system cmd case r of ExitFailure _ -> throwGhcExceptionIO (PhaseFailed cmd r) ExitSuccess -> do hash_str <- readFile tmp2 return $! readHexFingerprint hash_str -} ---------------------- -- mkOrphMap partitions instance decls or rules into -- (a) an OccEnv for ones that are not orphans, -- mapping the local OccName to a list of its decls -- (b) a list of orphan decls mkOrphMap :: (decl -> IsOrphan) -- Extract orphan status from decl -> [decl] -- Sorted into canonical order -> (OccEnv [decl], -- Non-orphan decls associated with their key; -- each sublist in canonical order [decl]) -- Orphan decls; in canonical order mkOrphMap get_key decls = foldl' go (emptyOccEnv, []) decls where go (non_orphs, orphs) d | NotOrphan occ <- get_key d = (extendOccEnv_Acc (:) Utils.singleton non_orphs occ d, orphs) | otherwise = (non_orphs, d:orphs) -- ----------------------------------------------------------------------------- -- Look up parents and versions of Names -- This is like a global version of the mi_hash_fn field in each ModIface. -- Given a Name, it finds the ModIface, and then uses mi_hash_fn to get -- the parent and version info. mkHashFun :: HscEnv -- needed to look up versions -> ExternalPackageState -- ditto -> (Name -> IO Fingerprint) mkHashFun hsc_env eps name | isHoleModule orig_mod = lookup (mkHomeModule home_unit (moduleName orig_mod)) | otherwise = lookup orig_mod where home_unit = hsc_home_unit hsc_env hpt = hsc_HPT hsc_env pit = eps_PIT eps occ = nameOccName name orig_mod = nameModule name lookup mod = do MASSERT2( isExternalName name, ppr name ) iface <- case lookupIfaceByModule hpt pit mod of Just iface -> return iface Nothing -> -- This can occur when we're writing out ifaces for -- requirements; we didn't do any /real/ typechecking -- so there's no guarantee everything is loaded. -- Kind of a heinous hack. initIfaceLoad hsc_env . withException $ withoutDynamicNow -- For some unknown reason, we need to reset the -- dynamicNow bit, otherwise only dynamic -- interfaces are looked up and some tests fail -- (e.g. T16219). $ loadInterface (text "lookupVers2") mod ImportBySystem return $ snd (mi_hash_fn (mi_final_exts iface) occ `orElse` pprPanic "lookupVers1" (ppr mod <+> ppr occ)) -- | Creates cached lookup for the 'mi_anns' field of ModIface -- Hackily, we use "module" as the OccName for any module-level annotations mkIfaceAnnCache :: [IfaceAnnotation] -> OccName -> [AnnPayload] mkIfaceAnnCache anns = \n -> lookupOccEnv env n `orElse` [] where pair (IfaceAnnotation target value) = (case target of NamedTarget occn -> occn ModuleTarget _ -> mkVarOcc "module" , [value]) -- flipping (++), so the first argument is always short env = mkOccEnv_C (flip (++)) (map pair anns)