diff options
Diffstat (limited to 'compiler/iface')
| -rw-r--r-- | compiler/iface/MkIface.hs | 100 |
1 files changed, 91 insertions, 9 deletions
diff --git a/compiler/iface/MkIface.hs b/compiler/iface/MkIface.hs index 40b6d025a1..261a8bfca2 100644 --- a/compiler/iface/MkIface.hs +++ b/compiler/iface/MkIface.hs @@ -115,6 +115,7 @@ import Control.Monad import Data.Function import Data.List import qualified Data.Map as Map +import qualified Data.Set as Set import Data.Ord import Data.IORef import System.Directory @@ -1177,8 +1178,8 @@ recompileRequired _ = True -- 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 Nothng means to --- rebuild the interface file not use the exisitng one. +-- 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 @@ -1486,11 +1487,30 @@ checkMergedSignatures mod_summary iface = do -- - 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 <textual reason>) if recompilation is required. checkDependencies :: HscEnv -> ModSummary -> ModIface -> IfG RecompileRequired checkDependencies hsc_env summary iface - = checkList (map dep_missing (ms_imps summary ++ ms_srcimps summary)) - where + = do + 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) @@ -1522,12 +1542,74 @@ checkDependencies hsc_env summary iface where pkg = moduleUnitId mod _otherwise -> return (RecompBecause reason) + old_deps = Set.fromList $ map fst $ filter (not . snd) prev_dep_mods + isOldHomeDeps = flip Set.member old_deps + checkForNewHomeDependency (L _ mname) = do + let + mod = mkModule this_pkg 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 fst $ filter (not . snd) $ + 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 + -> 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 "need version info for", ppr mod] - traceHiDiffs (text "Checking usages for module" <+> ppr mod) + 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; @@ -1537,12 +1619,12 @@ needInterface mod continue Failed _ -> do traceHiDiffs (sep [text "Couldn't load interface for module", ppr mod]) - return MustCompile + 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 -> continue iface + Succeeded iface -> Just <$> getter iface -- | Given the usage information extracted from the old -- M.hi file for the module being compiled, figure out |