{-# LANGUAGE ScopedTypeVariables #-} -- ----------------------------------------------------------------------------- -- -- (c) The University of Glasgow, 2011 -- -- This module implements multi-module compilation, and is used -- by --make and GHCi. -- -- ----------------------------------------------------------------------------- {-# OPTIONS -fno-warn-tabs #-} -- The above warning supression flag is a temporary kludge. -- While working on this module you are encouraged to remove it and -- detab the module (please do the detabbing in a separate patch). See -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#TabsvsSpaces -- for details module GhcMake( depanal, load, LoadHowMuch(..), topSortModuleGraph, noModError, cyclicModuleErr ) where #include "HsVersions.h" #ifdef GHCI import qualified Linker ( unload ) #endif import DriverPipeline import DriverPhases import GhcMonad import Module import HscTypes import ErrUtils import DynFlags import HsSyn import Finder import HeaderInfo import TcIface ( typecheckIface ) import TcRnMonad ( initIfaceCheck ) import RdrName ( RdrName ) import Exception ( evaluate, tryIO ) import Panic import SysTools import BasicTypes import SrcLoc import Util import Digraph import Bag ( listToBag ) import Maybes ( expectJust, mapCatMaybes ) import StringBuffer import FastString import Outputable import UniqFM import qualified Data.Map as Map import qualified FiniteMap as Map( insertListWith) import System.Directory ( doesFileExist, getModificationTime ) import System.IO ( fixIO ) import System.IO.Error ( isDoesNotExistError ) import System.Time ( ClockTime ) import System.FilePath import Control.Monad import Data.Maybe import Data.List import qualified Data.List as List -- ----------------------------------------------------------------------------- -- Loading the program -- | Perform a dependency analysis starting from the current targets -- and update the session with the new module graph. -- -- Dependency analysis entails parsing the @import@ directives and may -- therefore require running certain preprocessors. -- -- Note that each 'ModSummary' in the module graph caches its 'DynFlags'. -- These 'DynFlags' are determined by the /current/ session 'DynFlags' and the -- @OPTIONS@ and @LANGUAGE@ pragmas of the parsed module. Thus if you want to -- changes to the 'DynFlags' to take effect you need to call this function -- again. -- depanal :: GhcMonad m => [ModuleName] -- ^ excluded modules -> Bool -- ^ allow duplicate roots -> m ModuleGraph depanal excluded_mods allow_dup_roots = do hsc_env <- getSession let dflags = hsc_dflags hsc_env targets = hsc_targets hsc_env old_graph = hsc_mod_graph hsc_env liftIO $ showPass dflags "Chasing dependencies" liftIO $ debugTraceMsg dflags 2 (hcat [ text "Chasing modules from: ", hcat (punctuate comma (map pprTarget targets))]) mod_graph <- liftIO $ downsweep hsc_env old_graph excluded_mods allow_dup_roots modifySession $ \_ -> hsc_env { hsc_mod_graph = mod_graph } return mod_graph -- | Describes which modules of the module graph need to be loaded. data LoadHowMuch = LoadAllTargets -- ^ Load all targets and its dependencies. | LoadUpTo ModuleName -- ^ Load only the given module and its dependencies. | LoadDependenciesOf ModuleName -- ^ Load only the dependencies of the given module, but not the module -- itself. -- | Try to load the program. See 'LoadHowMuch' for the different modes. -- -- This function implements the core of GHC's @--make@ mode. It preprocesses, -- compiles and loads the specified modules, avoiding re-compilation wherever -- possible. Depending on the target (see 'DynFlags.hscTarget') compilating -- and loading may result in files being created on disk. -- -- Calls the 'reportModuleCompilationResult' callback after each compiling -- each module, whether successful or not. -- -- Throw a 'SourceError' if errors are encountered before the actual -- compilation starts (e.g., during dependency analysis). All other errors -- are reported using the callback. -- load :: GhcMonad m => LoadHowMuch -> m SuccessFlag load how_much = do mod_graph <- depanal [] False load2 how_much mod_graph load2 :: GhcMonad m => LoadHowMuch -> [ModSummary] -> m SuccessFlag load2 how_much mod_graph = do guessOutputFile hsc_env <- getSession let hpt1 = hsc_HPT hsc_env let dflags = hsc_dflags hsc_env -- The "bad" boot modules are the ones for which we have -- B.hs-boot in the module graph, but no B.hs -- The downsweep should have ensured this does not happen -- (see msDeps) let all_home_mods = [ms_mod_name s | s <- mod_graph, not (isBootSummary s)] bad_boot_mods = [s | s <- mod_graph, isBootSummary s, not (ms_mod_name s `elem` all_home_mods)] ASSERT( null bad_boot_mods ) return () -- check that the module given in HowMuch actually exists, otherwise -- topSortModuleGraph will bomb later. let checkHowMuch (LoadUpTo m) = checkMod m checkHowMuch (LoadDependenciesOf m) = checkMod m checkHowMuch _ = id checkMod m and_then | m `elem` all_home_mods = and_then | otherwise = do liftIO $ errorMsg dflags (text "no such module:" <+> quotes (ppr m)) return Failed checkHowMuch how_much $ do -- mg2_with_srcimps drops the hi-boot nodes, returning a -- graph with cycles. Among other things, it is used for -- backing out partially complete cycles following a failed -- upsweep, and for removing from hpt all the modules -- not in strict downwards closure, during calls to compile. let mg2_with_srcimps :: [SCC ModSummary] mg2_with_srcimps = topSortModuleGraph True mod_graph Nothing -- If we can determine that any of the {-# SOURCE #-} imports -- are definitely unnecessary, then emit a warning. warnUnnecessarySourceImports mg2_with_srcimps let -- check the stability property for each module. stable_mods@(stable_obj,stable_bco) = checkStability hpt1 mg2_with_srcimps all_home_mods -- prune bits of the HPT which are definitely redundant now, -- to save space. pruned_hpt = pruneHomePackageTable hpt1 (flattenSCCs mg2_with_srcimps) stable_mods _ <- liftIO $ evaluate pruned_hpt -- before we unload anything, make sure we don't leave an old -- interactive context around pointing to dead bindings. Also, -- write the pruned HPT to allow the old HPT to be GC'd. modifySession $ \_ -> hsc_env{ hsc_IC = emptyInteractiveContext, hsc_HPT = pruned_hpt } liftIO $ debugTraceMsg dflags 2 (text "Stable obj:" <+> ppr stable_obj $$ text "Stable BCO:" <+> ppr stable_bco) -- Unload any modules which are going to be re-linked this time around. let stable_linkables = [ linkable | m <- stable_obj++stable_bco, Just hmi <- [lookupUFM pruned_hpt m], Just linkable <- [hm_linkable hmi] ] liftIO $ unload hsc_env stable_linkables -- We could at this point detect cycles which aren't broken by -- a source-import, and complain immediately, but it seems better -- to let upsweep_mods do this, so at least some useful work gets -- done before the upsweep is abandoned. --hPutStrLn stderr "after tsort:\n" --hPutStrLn stderr (showSDoc (vcat (map ppr mg2))) -- Now do the upsweep, calling compile for each module in -- turn. Final result is version 3 of everything. -- Topologically sort the module graph, this time including hi-boot -- nodes, and possibly just including the portion of the graph -- reachable from the module specified in the 2nd argument to load. -- This graph should be cycle-free. -- If we're restricting the upsweep to a portion of the graph, we -- also want to retain everything that is still stable. let full_mg :: [SCC ModSummary] full_mg = topSortModuleGraph False mod_graph Nothing maybe_top_mod = case how_much of LoadUpTo m -> Just m LoadDependenciesOf m -> Just m _ -> Nothing partial_mg0 :: [SCC ModSummary] partial_mg0 = topSortModuleGraph False mod_graph maybe_top_mod -- LoadDependenciesOf m: we want the upsweep to stop just -- short of the specified module (unless the specified module -- is stable). partial_mg | LoadDependenciesOf _mod <- how_much = ASSERT( case last partial_mg0 of AcyclicSCC ms -> ms_mod_name ms == _mod; _ -> False ) List.init partial_mg0 | otherwise = partial_mg0 stable_mg = [ AcyclicSCC ms | AcyclicSCC ms <- full_mg, ms_mod_name ms `elem` stable_obj++stable_bco, ms_mod_name ms `notElem` [ ms_mod_name ms' | AcyclicSCC ms' <- partial_mg ] ] mg = stable_mg ++ partial_mg -- clean up between compilations let cleanup hsc_env = intermediateCleanTempFiles dflags (flattenSCCs mg2_with_srcimps) hsc_env liftIO $ debugTraceMsg dflags 2 (hang (text "Ready for upsweep") 2 (ppr mg)) setSession hsc_env{ hsc_HPT = emptyHomePackageTable } (upsweep_ok, modsUpswept) <- upsweep pruned_hpt stable_mods cleanup mg -- Make modsDone be the summaries for each home module now -- available; this should equal the domain of hpt3. -- Get in in a roughly top .. bottom order (hence reverse). let modsDone = reverse modsUpswept -- Try and do linking in some form, depending on whether the -- upsweep was completely or only partially successful. if succeeded upsweep_ok then -- Easy; just relink it all. do liftIO $ debugTraceMsg dflags 2 (text "Upsweep completely successful.") -- Clean up after ourselves hsc_env1 <- getSession liftIO $ intermediateCleanTempFiles dflags modsDone hsc_env1 -- Issue a warning for the confusing case where the user -- said '-o foo' but we're not going to do any linking. -- We attempt linking if either (a) one of the modules is -- called Main, or (b) the user said -no-hs-main, indicating -- that main() is going to come from somewhere else. -- let ofile = outputFile dflags let no_hs_main = dopt Opt_NoHsMain dflags let main_mod = mainModIs dflags a_root_is_Main = any ((==main_mod).ms_mod) mod_graph do_linking = a_root_is_Main || no_hs_main || ghcLink dflags == LinkDynLib when (ghcLink dflags == LinkBinary && isJust ofile && not do_linking) $ liftIO $ debugTraceMsg dflags 1 $ text ("Warning: output was redirected with -o, " ++ "but no output will be generated\n" ++ "because there is no " ++ moduleNameString (moduleName main_mod) ++ " module.") -- link everything together linkresult <- liftIO $ link (ghcLink dflags) dflags do_linking (hsc_HPT hsc_env1) loadFinish Succeeded linkresult else -- Tricky. We need to back out the effects of compiling any -- half-done cycles, both so as to clean up the top level envs -- and to avoid telling the interactive linker to link them. do liftIO $ debugTraceMsg dflags 2 (text "Upsweep partially successful.") let modsDone_names = map ms_mod modsDone let mods_to_zap_names = findPartiallyCompletedCycles modsDone_names mg2_with_srcimps let mods_to_keep = filter ((`notElem` mods_to_zap_names).ms_mod) modsDone hsc_env1 <- getSession let hpt4 = retainInTopLevelEnvs (map ms_mod_name mods_to_keep) (hsc_HPT hsc_env1) -- Clean up after ourselves liftIO $ intermediateCleanTempFiles dflags mods_to_keep hsc_env1 -- there should be no Nothings where linkables should be, now ASSERT(all (isJust.hm_linkable) (eltsUFM (hsc_HPT hsc_env))) do -- Link everything together linkresult <- liftIO $ link (ghcLink dflags) dflags False hpt4 modifySession $ \hsc_env -> hsc_env{ hsc_HPT = hpt4 } loadFinish Failed linkresult -- Finish up after a load. -- If the link failed, unload everything and return. loadFinish :: GhcMonad m => SuccessFlag -> SuccessFlag -> m SuccessFlag loadFinish _all_ok Failed = do hsc_env <- getSession liftIO $ unload hsc_env [] modifySession discardProg return Failed -- Empty the interactive context and set the module context to the topmost -- newly loaded module, or the Prelude if none were loaded. loadFinish all_ok Succeeded = do modifySession $ \hsc_env -> hsc_env{ hsc_IC = emptyInteractiveContext } return all_ok -- Forget the current program, but retain the persistent info in HscEnv discardProg :: HscEnv -> HscEnv discardProg hsc_env = hsc_env { hsc_mod_graph = emptyMG, hsc_IC = emptyInteractiveContext, hsc_HPT = emptyHomePackageTable } intermediateCleanTempFiles :: DynFlags -> [ModSummary] -> HscEnv -> IO () intermediateCleanTempFiles dflags summaries hsc_env = cleanTempFilesExcept dflags except where except = -- Save preprocessed files. The preprocessed file *might* be -- the same as the source file, but that doesn't do any -- harm. map ms_hspp_file summaries ++ -- Save object files for loaded modules. The point of this -- is that we might have generated and compiled a stub C -- file, and in the case of GHCi the object file will be a -- temporary file which we must not remove because we need -- to load/link it later. hptObjs (hsc_HPT hsc_env) -- | If there is no -o option, guess the name of target executable -- by using top-level source file name as a base. guessOutputFile :: GhcMonad m => m () guessOutputFile = modifySession $ \env -> let dflags = hsc_dflags env mod_graph = hsc_mod_graph env mainModuleSrcPath :: Maybe String mainModuleSrcPath = do let isMain = (== mainModIs dflags) . ms_mod [ms] <- return (filter isMain mod_graph) ml_hs_file (ms_location ms) name = fmap dropExtension mainModuleSrcPath #if defined(mingw32_HOST_OS) -- we must add the .exe extention unconditionally here, otherwise -- when name has an extension of its own, the .exe extension will -- not be added by DriverPipeline.exeFileName. See #2248 name_exe = fmap (<.> "exe") name #else name_exe = name #endif in case outputFile dflags of Just _ -> env Nothing -> env { hsc_dflags = dflags { outputFile = name_exe } } -- ----------------------------------------------------------------------------- -- | Prune the HomePackageTable -- -- Before doing an upsweep, we can throw away: -- -- - For non-stable modules: -- - all ModDetails, all linked code -- - all unlinked code that is out of date with respect to -- the source file -- -- This is VERY IMPORTANT otherwise we'll end up requiring 2x the -- space at the end of the upsweep, because the topmost ModDetails of the -- old HPT holds on to the entire type environment from the previous -- compilation. pruneHomePackageTable :: HomePackageTable -> [ModSummary] -> ([ModuleName],[ModuleName]) -> HomePackageTable pruneHomePackageTable hpt summ (stable_obj, stable_bco) = mapUFM prune hpt where prune hmi | is_stable modl = hmi' | otherwise = hmi'{ hm_details = emptyModDetails } where modl = moduleName (mi_module (hm_iface hmi)) hmi' | Just l <- hm_linkable hmi, linkableTime l < ms_hs_date ms = hmi{ hm_linkable = Nothing } | otherwise = hmi where ms = expectJust "prune" (lookupUFM ms_map modl) ms_map = listToUFM [(ms_mod_name ms, ms) | ms <- summ] is_stable m = m `elem` stable_obj || m `elem` stable_bco -- ----------------------------------------------------------------------------- -- Return (names of) all those in modsDone who are part of a cycle -- as defined by theGraph. findPartiallyCompletedCycles :: [Module] -> [SCC ModSummary] -> [Module] findPartiallyCompletedCycles modsDone theGraph = chew theGraph where chew [] = [] chew ((AcyclicSCC _):rest) = chew rest -- acyclic? not interesting. chew ((CyclicSCC vs):rest) = let names_in_this_cycle = nub (map ms_mod vs) mods_in_this_cycle = nub ([done | done <- modsDone, done `elem` names_in_this_cycle]) chewed_rest = chew rest in if notNull mods_in_this_cycle && length mods_in_this_cycle < length names_in_this_cycle then mods_in_this_cycle ++ chewed_rest else chewed_rest -- --------------------------------------------------------------------------- -- Unloading unload :: HscEnv -> [Linkable] -> IO () unload hsc_env stable_linkables -- Unload everthing *except* 'stable_linkables' = case ghcLink (hsc_dflags hsc_env) of #ifdef GHCI LinkInMemory -> Linker.unload (hsc_dflags hsc_env) stable_linkables #else LinkInMemory -> panic "unload: no interpreter" -- urgh. avoid warnings: hsc_env stable_linkables #endif _other -> return () -- ----------------------------------------------------------------------------- {- | Stability tells us which modules definitely do not need to be recompiled. There are two main reasons for having stability: - avoid doing a complete upsweep of the module graph in GHCi when modules near the bottom of the tree have not changed. - to tell GHCi when it can load object code: we can only load object code for a module when we also load object code fo all of the imports of the module. So we need to know that we will definitely not be recompiling any of these modules, and we can use the object code. The stability check is as follows. Both stableObject and stableBCO are used during the upsweep phase later. @ stable m = stableObject m || stableBCO m stableObject m = all stableObject (imports m) && old linkable does not exist, or is == on-disk .o && date(on-disk .o) > date(.hs) stableBCO m = all stable (imports m) && date(BCO) > date(.hs) @ These properties embody the following ideas: - if a module is stable, then: - if it has been compiled in a previous pass (present in HPT) then it does not need to be compiled or re-linked. - if it has not been compiled in a previous pass, then we only need to read its .hi file from disk and link it to produce a 'ModDetails'. - if a modules is not stable, we will definitely be at least re-linking, and possibly re-compiling it during the 'upsweep'. All non-stable modules can (and should) therefore be unlinked before the 'upsweep'. - Note that objects are only considered stable if they only depend on other objects. We can't link object code against byte code. -} checkStability :: HomePackageTable -- HPT from last compilation -> [SCC ModSummary] -- current module graph (cyclic) -> [ModuleName] -- all home modules -> ([ModuleName], -- stableObject [ModuleName]) -- stableBCO checkStability hpt sccs all_home_mods = foldl checkSCC ([],[]) sccs where checkSCC (stable_obj, stable_bco) scc0 | stableObjects = (scc_mods ++ stable_obj, stable_bco) | stableBCOs = (stable_obj, scc_mods ++ stable_bco) | otherwise = (stable_obj, stable_bco) where scc = flattenSCC scc0 scc_mods = map ms_mod_name scc home_module m = m `elem` all_home_mods && m `notElem` scc_mods scc_allimps = nub (filter home_module (concatMap ms_home_allimps scc)) -- all imports outside the current SCC, but in the home pkg stable_obj_imps = map (`elem` stable_obj) scc_allimps stable_bco_imps = map (`elem` stable_bco) scc_allimps stableObjects = and stable_obj_imps && all object_ok scc stableBCOs = and (zipWith (||) stable_obj_imps stable_bco_imps) && all bco_ok scc object_ok ms | Just t <- ms_obj_date ms = t >= ms_hs_date ms && same_as_prev t | otherwise = False where same_as_prev t = case lookupUFM hpt (ms_mod_name ms) of Just hmi | Just l <- hm_linkable hmi -> isObjectLinkable l && t == linkableTime l _other -> True -- why '>=' rather than '>' above? If the filesystem stores -- times to the nearset second, we may occasionally find that -- the object & source have the same modification time, -- especially if the source was automatically generated -- and compiled. Using >= is slightly unsafe, but it matches -- make's behaviour. -- -- But see #5527, where someone ran into this and it caused -- a problem. bco_ok ms = case lookupUFM hpt (ms_mod_name ms) of Just hmi | Just l <- hm_linkable hmi -> not (isObjectLinkable l) && linkableTime l >= ms_hs_date ms _other -> False -- ----------------------------------------------------------------------------- -- | The upsweep -- -- This is where we compile each module in the module graph, in a pass -- from the bottom to the top of the graph. -- -- There better had not be any cyclic groups here -- we check for them. upsweep :: GhcMonad m => HomePackageTable -- ^ HPT from last time round (pruned) -> ([ModuleName],[ModuleName]) -- ^ stable modules (see checkStability) -> (HscEnv -> IO ()) -- ^ How to clean up unwanted tmp files -> [SCC ModSummary] -- ^ Mods to do (the worklist) -> m (SuccessFlag, [ModSummary]) -- ^ Returns: -- -- 1. A flag whether the complete upsweep was successful. -- 2. The 'HscEnv' in the monad has an updated HPT -- 3. A list of modules which succeeded loading. upsweep old_hpt stable_mods cleanup sccs = do (res, done) <- upsweep' old_hpt [] sccs 1 (length sccs) return (res, reverse done) where upsweep' _old_hpt done [] _ _ = return (Succeeded, done) upsweep' _old_hpt done (CyclicSCC ms:_) _ _ = do dflags <- getSessionDynFlags liftIO $ fatalErrorMsg dflags (cyclicModuleErr ms) return (Failed, done) upsweep' old_hpt done (AcyclicSCC mod:mods) mod_index nmods = do -- putStrLn ("UPSWEEP_MOD: hpt = " ++ -- show (map (moduleUserString.moduleName.mi_module.hm_iface) -- (moduleEnvElts (hsc_HPT hsc_env))) let logger _mod = defaultWarnErrLogger hsc_env <- getSession -- Remove unwanted tmp files between compilations liftIO (cleanup hsc_env) mb_mod_info <- handleSourceError (\err -> do logger mod (Just err); return Nothing) $ do mod_info <- liftIO $ upsweep_mod hsc_env old_hpt stable_mods mod mod_index nmods logger mod Nothing -- log warnings return (Just mod_info) case mb_mod_info of Nothing -> return (Failed, done) Just mod_info -> do let this_mod = ms_mod_name mod -- Add new info to hsc_env hpt1 = addToUFM (hsc_HPT hsc_env) this_mod mod_info hsc_env1 = hsc_env { hsc_HPT = hpt1 } -- Space-saving: delete the old HPT entry -- for mod BUT if mod is a hs-boot -- node, don't delete it. For the -- interface, the HPT entry is probaby for the -- main Haskell source file. Deleting it -- would force the real module to be recompiled -- every time. old_hpt1 | isBootSummary mod = old_hpt | otherwise = delFromUFM old_hpt this_mod done' = mod:done -- fixup our HomePackageTable after we've finished compiling -- a mutually-recursive loop. See reTypecheckLoop, below. hsc_env2 <- liftIO $ reTypecheckLoop hsc_env1 mod done' setSession hsc_env2 upsweep' old_hpt1 done' mods (mod_index+1) nmods -- | Compile a single module. Always produce a Linkable for it if -- successful. If no compilation happened, return the old Linkable. upsweep_mod :: HscEnv -> HomePackageTable -> ([ModuleName],[ModuleName]) -> ModSummary -> Int -- index of module -> Int -- total number of modules -> IO HomeModInfo upsweep_mod hsc_env old_hpt (stable_obj, stable_bco) summary mod_index nmods = let this_mod_name = ms_mod_name summary this_mod = ms_mod summary mb_obj_date = ms_obj_date summary obj_fn = ml_obj_file (ms_location summary) hs_date = ms_hs_date summary is_stable_obj = this_mod_name `elem` stable_obj is_stable_bco = this_mod_name `elem` stable_bco old_hmi = lookupUFM old_hpt this_mod_name -- We're using the dflags for this module now, obtained by -- applying any options in its LANGUAGE & OPTIONS_GHC pragmas. dflags = ms_hspp_opts summary prevailing_target = hscTarget (hsc_dflags hsc_env) local_target = hscTarget dflags -- If OPTIONS_GHC contains -fasm or -fvia-C, be careful that -- we don't do anything dodgy: these should only work to change -- from -fvia-C to -fasm and vice-versa, otherwise we could -- end up trying to link object code to byte code. target = if prevailing_target /= local_target && (not (isObjectTarget prevailing_target) || not (isObjectTarget local_target)) then prevailing_target else local_target -- store the corrected hscTarget into the summary summary' = summary{ ms_hspp_opts = dflags { hscTarget = target } } -- The old interface is ok if -- a) we're compiling a source file, and the old HPT -- entry is for a source file -- b) we're compiling a hs-boot file -- Case (b) allows an hs-boot file to get the interface of its -- real source file on the second iteration of the compilation -- manager, but that does no harm. Otherwise the hs-boot file -- will always be recompiled mb_old_iface = case old_hmi of Nothing -> Nothing Just hm_info | isBootSummary summary -> Just iface | not (mi_boot iface) -> Just iface | otherwise -> Nothing where iface = hm_iface hm_info compile_it :: Maybe Linkable -> SourceModified -> IO HomeModInfo compile_it mb_linkable src_modified = compile hsc_env summary' mod_index nmods mb_old_iface mb_linkable src_modified compile_it_discard_iface :: Maybe Linkable -> SourceModified -> IO HomeModInfo compile_it_discard_iface mb_linkable src_modified = compile hsc_env summary' mod_index nmods Nothing mb_linkable src_modified -- With the HscNothing target we create empty linkables to avoid -- recompilation. We have to detect these to recompile anyway if -- the target changed since the last compile. is_fake_linkable | Just hmi <- old_hmi, Just l <- hm_linkable hmi = null (linkableUnlinked l) | otherwise = -- we have no linkable, so it cannot be fake False implies False _ = True implies True x = x in case () of _ -- Regardless of whether we're generating object code or -- byte code, we can always use an existing object file -- if it is *stable* (see checkStability). | is_stable_obj, Just hmi <- old_hmi -> do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "skipping stable obj mod:" <+> ppr this_mod_name) return hmi -- object is stable, and we have an entry in the -- old HPT: nothing to do | is_stable_obj, isNothing old_hmi -> do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "compiling stable on-disk mod:" <+> ppr this_mod_name) linkable <- liftIO $ findObjectLinkable this_mod obj_fn (expectJust "upsweep1" mb_obj_date) compile_it (Just linkable) SourceUnmodifiedAndStable -- object is stable, but we need to load the interface -- off disk to make a HMI. | not (isObjectTarget target), is_stable_bco, (target /= HscNothing) `implies` not is_fake_linkable -> ASSERT(isJust old_hmi) -- must be in the old_hpt let Just hmi = old_hmi in do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "skipping stable BCO mod:" <+> ppr this_mod_name) return hmi -- BCO is stable: nothing to do | not (isObjectTarget target), Just hmi <- old_hmi, Just l <- hm_linkable hmi, not (isObjectLinkable l), (target /= HscNothing) `implies` not is_fake_linkable, linkableTime l >= ms_hs_date summary -> do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "compiling non-stable BCO mod:" <+> ppr this_mod_name) compile_it (Just l) SourceUnmodified -- we have an old BCO that is up to date with respect -- to the source: do a recompilation check as normal. -- When generating object code, if there's an up-to-date -- object file on the disk, then we can use it. -- However, if the object file is new (compared to any -- linkable we had from a previous compilation), then we -- must discard any in-memory interface, because this -- means the user has compiled the source file -- separately and generated a new interface, that we must -- read from the disk. -- | isObjectTarget target, Just obj_date <- mb_obj_date, obj_date >= hs_date -> do case old_hmi of Just hmi | Just l <- hm_linkable hmi, isObjectLinkable l && linkableTime l == obj_date -> do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "compiling mod with new on-disk obj:" <+> ppr this_mod_name) compile_it (Just l) SourceUnmodified _otherwise -> do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "compiling mod with new on-disk obj2:" <+> ppr this_mod_name) linkable <- liftIO $ findObjectLinkable this_mod obj_fn obj_date compile_it_discard_iface (Just linkable) SourceUnmodified _otherwise -> do liftIO $ debugTraceMsg (hsc_dflags hsc_env) 5 (text "compiling mod:" <+> ppr this_mod_name) compile_it Nothing SourceModified -- Filter modules in the HPT retainInTopLevelEnvs :: [ModuleName] -> HomePackageTable -> HomePackageTable retainInTopLevelEnvs keep_these hpt = listToUFM [ (mod, expectJust "retain" mb_mod_info) | mod <- keep_these , let mb_mod_info = lookupUFM hpt mod , isJust mb_mod_info ] -- --------------------------------------------------------------------------- -- Typecheck module loops {- See bug #930. This code fixes a long-standing bug in --make. The problem is that when compiling the modules *inside* a loop, a data type that is only defined at the top of the loop looks opaque; but after the loop is done, the structure of the data type becomes apparent. The difficulty is then that two different bits of code have different notions of what the data type looks like. The idea is that after we compile a module which also has an .hs-boot file, we re-generate the ModDetails for each of the modules that depends on the .hs-boot file, so that everyone points to the proper TyCons, Ids etc. defined by the real module, not the boot module. Fortunately re-generating a ModDetails from a ModIface is easy: the function TcIface.typecheckIface does exactly that. Picking the modules to re-typecheck is slightly tricky. Starting from the module graph consisting of the modules that have already been compiled, we reverse the edges (so they point from the imported module to the importing module), and depth-first-search from the .hs-boot node. This gives us all the modules that depend transitively on the .hs-boot module, and those are exactly the modules that we need to re-typecheck. Following this fix, GHC can compile itself with --make -O2. -} reTypecheckLoop :: HscEnv -> ModSummary -> ModuleGraph -> IO HscEnv reTypecheckLoop hsc_env ms graph | not (isBootSummary ms) && any (\m -> ms_mod m == this_mod && isBootSummary m) graph = do let mss = reachableBackwards (ms_mod_name ms) graph non_boot = filter (not.isBootSummary) mss debugTraceMsg (hsc_dflags hsc_env) 2 $ text "Re-typechecking loop: " <> ppr (map ms_mod_name non_boot) typecheckLoop hsc_env (map ms_mod_name non_boot) | otherwise = return hsc_env where this_mod = ms_mod ms typecheckLoop :: HscEnv -> [ModuleName] -> IO HscEnv typecheckLoop hsc_env mods = do new_hpt <- fixIO $ \new_hpt -> do let new_hsc_env = hsc_env{ hsc_HPT = new_hpt } mds <- initIfaceCheck new_hsc_env $ mapM (typecheckIface . hm_iface) hmis let new_hpt = addListToUFM old_hpt (zip mods [ hmi{ hm_details = details } | (hmi,details) <- zip hmis mds ]) return new_hpt return hsc_env{ hsc_HPT = new_hpt } where old_hpt = hsc_HPT hsc_env hmis = map (expectJust "typecheckLoop" . lookupUFM old_hpt) mods reachableBackwards :: ModuleName -> [ModSummary] -> [ModSummary] reachableBackwards mod summaries = [ ms | (ms,_,_) <- reachableG (transposeG graph) root ] where -- the rest just sets up the graph: (graph, lookup_node) = moduleGraphNodes False summaries root = expectJust "reachableBackwards" (lookup_node HsBootFile mod) -- --------------------------------------------------------------------------- -- Topological sort of the module graph type SummaryNode = (ModSummary, Int, [Int]) topSortModuleGraph :: Bool -- ^ Drop hi-boot nodes? (see below) -> [ModSummary] -> Maybe ModuleName -- ^ Root module name. If @Nothing@, use the full graph. -> [SCC ModSummary] -- ^ Calculate SCCs of the module graph, possibly dropping the hi-boot nodes -- The resulting list of strongly-connected-components is in topologically -- sorted order, starting with the module(s) at the bottom of the -- dependency graph (ie compile them first) and ending with the ones at -- the top. -- -- Drop hi-boot nodes (first boolean arg)? -- -- - @False@: treat the hi-boot summaries as nodes of the graph, -- so the graph must be acyclic -- -- - @True@: eliminate the hi-boot nodes, and instead pretend -- the a source-import of Foo is an import of Foo -- The resulting graph has no hi-boot nodes, but can be cyclic topSortModuleGraph drop_hs_boot_nodes summaries mb_root_mod = map (fmap summaryNodeSummary) $ stronglyConnCompG initial_graph where (graph, lookup_node) = moduleGraphNodes drop_hs_boot_nodes summaries initial_graph = case mb_root_mod of Nothing -> graph Just root_mod -> -- restrict the graph to just those modules reachable from -- the specified module. We do this by building a graph with -- the full set of nodes, and determining the reachable set from -- the specified node. let root | Just node <- lookup_node HsSrcFile root_mod, graph `hasVertexG` node = node | otherwise = ghcError (ProgramError "module does not exist") in graphFromEdgedVertices (seq root (reachableG graph root)) summaryNodeKey :: SummaryNode -> Int summaryNodeKey (_, k, _) = k summaryNodeSummary :: SummaryNode -> ModSummary summaryNodeSummary (s, _, _) = s moduleGraphNodes :: Bool -> [ModSummary] -> (Graph SummaryNode, HscSource -> ModuleName -> Maybe SummaryNode) moduleGraphNodes drop_hs_boot_nodes summaries = (graphFromEdgedVertices nodes, lookup_node) where numbered_summaries = zip summaries [1..] lookup_node :: HscSource -> ModuleName -> Maybe SummaryNode lookup_node hs_src mod = Map.lookup (mod, hs_src) node_map lookup_key :: HscSource -> ModuleName -> Maybe Int lookup_key hs_src mod = fmap summaryNodeKey (lookup_node hs_src mod) node_map :: NodeMap SummaryNode node_map = Map.fromList [ ((moduleName (ms_mod s), ms_hsc_src s), node) | node@(s, _, _) <- nodes ] -- We use integers as the keys for the SCC algorithm nodes :: [SummaryNode] nodes = [ (s, key, out_keys) | (s, key) <- numbered_summaries -- Drop the hi-boot ones if told to do so , not (isBootSummary s && drop_hs_boot_nodes) , let out_keys = out_edge_keys hs_boot_key (map unLoc (ms_home_srcimps s)) ++ out_edge_keys HsSrcFile (map unLoc (ms_home_imps s)) ++ (-- see [boot-edges] below if drop_hs_boot_nodes || ms_hsc_src s == HsBootFile then [] else case lookup_key HsBootFile (ms_mod_name s) of Nothing -> [] Just k -> [k]) ] -- [boot-edges] if this is a .hs and there is an equivalent -- .hs-boot, add a link from the former to the latter. This -- has the effect of detecting bogus cases where the .hs-boot -- depends on the .hs, by introducing a cycle. Additionally, -- it ensures that we will always process the .hs-boot before -- the .hs, and so the HomePackageTable will always have the -- most up to date information. -- Drop hs-boot nodes by using HsSrcFile as the key hs_boot_key | drop_hs_boot_nodes = HsSrcFile | otherwise = HsBootFile out_edge_keys :: HscSource -> [ModuleName] -> [Int] out_edge_keys hi_boot ms = mapCatMaybes (lookup_key hi_boot) ms -- If we want keep_hi_boot_nodes, then we do lookup_key with -- the IsBootInterface parameter True; else False type NodeKey = (ModuleName, HscSource) -- The nodes of the graph are type NodeMap a = Map.Map NodeKey a -- keyed by (mod, src_file_type) pairs msKey :: ModSummary -> NodeKey msKey (ModSummary { ms_mod = mod, ms_hsc_src = boot }) = (moduleName mod,boot) mkNodeMap :: [ModSummary] -> NodeMap ModSummary mkNodeMap summaries = Map.fromList [ (msKey s, s) | s <- summaries] nodeMapElts :: NodeMap a -> [a] nodeMapElts = Map.elems -- | If there are {-# SOURCE #-} imports between strongly connected -- components in the topological sort, then those imports can -- definitely be replaced by ordinary non-SOURCE imports: if SOURCE -- were necessary, then the edge would be part of a cycle. warnUnnecessarySourceImports :: GhcMonad m => [SCC ModSummary] -> m () warnUnnecessarySourceImports sccs = do logWarnings (listToBag (concatMap (check.flattenSCC) sccs)) where check ms = let mods_in_this_cycle = map ms_mod_name ms in [ warn i | m <- ms, i <- ms_home_srcimps m, unLoc i `notElem` mods_in_this_cycle ] warn :: Located ModuleName -> WarnMsg warn (L loc mod) = mkPlainErrMsg loc (ptext (sLit "Warning: {-# SOURCE #-} unnecessary in import of ") <+> quotes (ppr mod)) ----------------------------------------------------------------------------- -- Downsweep (dependency analysis) -- Chase downwards from the specified root set, returning summaries -- for all home modules encountered. Only follow source-import -- links. -- We pass in the previous collection of summaries, which is used as a -- cache to avoid recalculating a module summary if the source is -- unchanged. -- -- The returned list of [ModSummary] nodes has one node for each home-package -- module, plus one for any hs-boot files. The imports of these nodes -- are all there, including the imports of non-home-package modules. downsweep :: HscEnv -> [ModSummary] -- Old summaries -> [ModuleName] -- Ignore dependencies on these; treat -- them as if they were package modules -> Bool -- True <=> allow multiple targets to have -- the same module name; this is -- very useful for ghc -M -> IO [ModSummary] -- The elts of [ModSummary] all have distinct -- (Modules, IsBoot) identifiers, unless the Bool is true -- in which case there can be repeats downsweep hsc_env old_summaries excl_mods allow_dup_roots = do rootSummaries <- mapM getRootSummary roots let root_map = mkRootMap rootSummaries checkDuplicates root_map summs <- loop (concatMap msDeps rootSummaries) root_map return summs where roots = hsc_targets hsc_env old_summary_map :: NodeMap ModSummary old_summary_map = mkNodeMap old_summaries getRootSummary :: Target -> IO ModSummary getRootSummary (Target (TargetFile file mb_phase) obj_allowed maybe_buf) = do exists <- liftIO $ doesFileExist file if exists then summariseFile hsc_env old_summaries file mb_phase obj_allowed maybe_buf else throwOneError $ mkPlainErrMsg noSrcSpan $ text "can't find file:" <+> text file getRootSummary (Target (TargetModule modl) obj_allowed maybe_buf) = do maybe_summary <- summariseModule hsc_env old_summary_map False (L rootLoc modl) obj_allowed maybe_buf excl_mods case maybe_summary of Nothing -> packageModErr modl Just s -> return s rootLoc = mkGeneralSrcSpan (fsLit "") -- In a root module, the filename is allowed to diverge from the module -- name, so we have to check that there aren't multiple root files -- defining the same module (otherwise the duplicates will be silently -- ignored, leading to confusing behaviour). checkDuplicates :: NodeMap [ModSummary] -> IO () checkDuplicates root_map | allow_dup_roots = return () | null dup_roots = return () | otherwise = liftIO $ multiRootsErr (head dup_roots) where dup_roots :: [[ModSummary]] -- Each at least of length 2 dup_roots = filterOut isSingleton (nodeMapElts root_map) loop :: [(Located ModuleName,IsBootInterface)] -- Work list: process these modules -> NodeMap [ModSummary] -- Visited set; the range is a list because -- the roots can have the same module names -- if allow_dup_roots is True -> IO [ModSummary] -- The result includes the worklist, except -- for those mentioned in the visited set loop [] done = return (concat (nodeMapElts done)) loop ((wanted_mod, is_boot) : ss) done | Just summs <- Map.lookup key done = if isSingleton summs then loop ss done else do { multiRootsErr summs; return [] } | otherwise = do mb_s <- summariseModule hsc_env old_summary_map is_boot wanted_mod True Nothing excl_mods case mb_s of Nothing -> loop ss done Just s -> loop (msDeps s ++ ss) (Map.insert key [s] done) where key = (unLoc wanted_mod, if is_boot then HsBootFile else HsSrcFile) -- XXX Does the (++) here need to be flipped? mkRootMap :: [ModSummary] -> NodeMap [ModSummary] mkRootMap summaries = Map.insertListWith (flip (++)) [ (msKey s, [s]) | s <- summaries ] Map.empty msDeps :: ModSummary -> [(Located ModuleName, IsBootInterface)] -- (msDeps s) returns the dependencies of the ModSummary s. -- A wrinkle is that for a {-# SOURCE #-} import we return -- *both* the hs-boot file -- *and* the source file -- as "dependencies". That ensures that the list of all relevant -- modules always contains B.hs if it contains B.hs-boot. -- Remember, this pass isn't doing the topological sort. It's -- just gathering the list of all relevant ModSummaries msDeps s = concat [ [(m,True), (m,False)] | m <- ms_home_srcimps s ] ++ [ (m,False) | m <- ms_home_imps s ] home_imps :: [Located (ImportDecl RdrName)] -> [Located ModuleName] home_imps imps = [ ideclName i | L _ i <- imps, isLocal (ideclPkgQual i) ] where isLocal Nothing = True isLocal (Just pkg) | pkg == fsLit "this" = True -- "this" is special isLocal _ = False ms_home_allimps :: ModSummary -> [ModuleName] ms_home_allimps ms = map unLoc (ms_home_srcimps ms ++ ms_home_imps ms) ms_home_srcimps :: ModSummary -> [Located ModuleName] ms_home_srcimps = home_imps . ms_srcimps ms_home_imps :: ModSummary -> [Located ModuleName] ms_home_imps = home_imps . ms_imps ----------------------------------------------------------------------------- -- Summarising modules -- We have two types of summarisation: -- -- * Summarise a file. This is used for the root module(s) passed to -- cmLoadModules. The file is read, and used to determine the root -- module name. The module name may differ from the filename. -- -- * Summarise a module. We are given a module name, and must provide -- a summary. The finder is used to locate the file in which the module -- resides. summariseFile :: HscEnv -> [ModSummary] -- old summaries -> FilePath -- source file name -> Maybe Phase -- start phase -> Bool -- object code allowed? -> Maybe (StringBuffer,ClockTime) -> IO ModSummary summariseFile hsc_env old_summaries file mb_phase obj_allowed maybe_buf -- we can use a cached summary if one is available and the -- source file hasn't changed, But we have to look up the summary -- by source file, rather than module name as we do in summarise. | Just old_summary <- findSummaryBySourceFile old_summaries file = do let location = ms_location old_summary -- return the cached summary if the source didn't change src_timestamp <- case maybe_buf of Just (_,t) -> return t Nothing -> liftIO $ getModificationTime file -- The file exists; we checked in getRootSummary above. -- If it gets removed subsequently, then this -- getModificationTime may fail, but that's the right -- behaviour. if ms_hs_date old_summary == src_timestamp then do -- update the object-file timestamp obj_timestamp <- if isObjectTarget (hscTarget (hsc_dflags hsc_env)) || obj_allowed -- bug #1205 then liftIO $ getObjTimestamp location False else return Nothing return old_summary{ ms_obj_date = obj_timestamp } else new_summary | otherwise = new_summary where new_summary = do let dflags = hsc_dflags hsc_env (dflags', hspp_fn, buf) <- preprocessFile hsc_env file mb_phase maybe_buf (srcimps,the_imps, L _ mod_name) <- getImports dflags' buf hspp_fn file -- Make a ModLocation for this file location <- liftIO $ mkHomeModLocation dflags mod_name file -- Tell the Finder cache where it is, so that subsequent calls -- to findModule will find it, even if it's not on any search path mod <- liftIO $ addHomeModuleToFinder hsc_env mod_name location src_timestamp <- case maybe_buf of Just (_,t) -> return t Nothing -> liftIO $ getModificationTime file -- getMofificationTime may fail -- when the user asks to load a source file by name, we only -- use an object file if -fobject-code is on. See #1205. obj_timestamp <- if isObjectTarget (hscTarget (hsc_dflags hsc_env)) || obj_allowed -- bug #1205 then liftIO $ modificationTimeIfExists (ml_obj_file location) else return Nothing return (ModSummary { ms_mod = mod, ms_hsc_src = HsSrcFile, ms_location = location, ms_hspp_file = hspp_fn, ms_hspp_opts = dflags', ms_hspp_buf = Just buf, ms_srcimps = srcimps, ms_textual_imps = the_imps, ms_hs_date = src_timestamp, ms_obj_date = obj_timestamp }) findSummaryBySourceFile :: [ModSummary] -> FilePath -> Maybe ModSummary findSummaryBySourceFile summaries file = case [ ms | ms <- summaries, HsSrcFile <- [ms_hsc_src ms], expectJust "findSummaryBySourceFile" (ml_hs_file (ms_location ms)) == file ] of [] -> Nothing (x:_) -> Just x -- Summarise a module, and pick up source and timestamp. summariseModule :: HscEnv -> NodeMap ModSummary -- Map of old summaries -> IsBootInterface -- True <=> a {-# SOURCE #-} import -> Located ModuleName -- Imported module to be summarised -> Bool -- object code allowed? -> Maybe (StringBuffer, ClockTime) -> [ModuleName] -- Modules to exclude -> IO (Maybe ModSummary) -- Its new summary summariseModule hsc_env old_summary_map is_boot (L loc wanted_mod) obj_allowed maybe_buf excl_mods | wanted_mod `elem` excl_mods = return Nothing | Just old_summary <- Map.lookup (wanted_mod, hsc_src) old_summary_map = do -- Find its new timestamp; all the -- ModSummaries in the old map have valid ml_hs_files let location = ms_location old_summary src_fn = expectJust "summariseModule" (ml_hs_file location) -- check the modification time on the source file, and -- return the cached summary if it hasn't changed. If the -- file has disappeared, we need to call the Finder again. case maybe_buf of Just (_,t) -> check_timestamp old_summary location src_fn t Nothing -> do m <- tryIO (getModificationTime src_fn) case m of Right t -> check_timestamp old_summary location src_fn t Left e | isDoesNotExistError e -> find_it | otherwise -> ioError e | otherwise = find_it where dflags = hsc_dflags hsc_env hsc_src = if is_boot then HsBootFile else HsSrcFile check_timestamp old_summary location src_fn src_timestamp | ms_hs_date old_summary == src_timestamp = do -- update the object-file timestamp obj_timestamp <- if isObjectTarget (hscTarget (hsc_dflags hsc_env)) || obj_allowed -- bug #1205 then getObjTimestamp location is_boot else return Nothing return (Just old_summary{ ms_obj_date = obj_timestamp }) | otherwise = -- source changed: re-summarise. new_summary location (ms_mod old_summary) src_fn src_timestamp find_it = do -- Don't use the Finder's cache this time. If the module was -- previously a package module, it may have now appeared on the -- search path, so we want to consider it to be a home module. If -- the module was previously a home module, it may have moved. uncacheModule hsc_env wanted_mod found <- findImportedModule hsc_env wanted_mod Nothing case found of Found location mod | isJust (ml_hs_file location) -> -- Home package just_found location mod | otherwise -> -- Drop external-pkg ASSERT(modulePackageId mod /= thisPackage dflags) return Nothing err -> noModError dflags loc wanted_mod err -- Not found just_found location mod = do -- Adjust location to point to the hs-boot source file, -- hi file, object file, when is_boot says so let location' | is_boot = addBootSuffixLocn location | otherwise = location src_fn = expectJust "summarise2" (ml_hs_file location') -- Check that it exists -- It might have been deleted since the Finder last found it maybe_t <- modificationTimeIfExists src_fn case maybe_t of Nothing -> noHsFileErr loc src_fn Just t -> new_summary location' mod src_fn t new_summary location mod src_fn src_timestamp = do -- Preprocess the source file and get its imports -- The dflags' contains the OPTIONS pragmas (dflags', hspp_fn, buf) <- preprocessFile hsc_env src_fn Nothing maybe_buf (srcimps, the_imps, L mod_loc mod_name) <- getImports dflags' buf hspp_fn src_fn when (mod_name /= wanted_mod) $ throwOneError $ mkPlainErrMsg mod_loc $ text "File name does not match module name:" $$ text "Saw:" <+> quotes (ppr mod_name) $$ text "Expected:" <+> quotes (ppr wanted_mod) -- Find the object timestamp, and return the summary obj_timestamp <- if isObjectTarget (hscTarget (hsc_dflags hsc_env)) || obj_allowed -- bug #1205 then getObjTimestamp location is_boot else return Nothing return (Just (ModSummary { ms_mod = mod, ms_hsc_src = hsc_src, ms_location = location, ms_hspp_file = hspp_fn, ms_hspp_opts = dflags', ms_hspp_buf = Just buf, ms_srcimps = srcimps, ms_textual_imps = the_imps, ms_hs_date = src_timestamp, ms_obj_date = obj_timestamp })) getObjTimestamp :: ModLocation -> Bool -> IO (Maybe ClockTime) getObjTimestamp location is_boot = if is_boot then return Nothing else modificationTimeIfExists (ml_obj_file location) preprocessFile :: HscEnv -> FilePath -> Maybe Phase -- ^ Starting phase -> Maybe (StringBuffer,ClockTime) -> IO (DynFlags, FilePath, StringBuffer) preprocessFile hsc_env src_fn mb_phase Nothing = do (dflags', hspp_fn) <- preprocess hsc_env (src_fn, mb_phase) buf <- hGetStringBuffer hspp_fn return (dflags', hspp_fn, buf) preprocessFile hsc_env src_fn mb_phase (Just (buf, _time)) = do let dflags = hsc_dflags hsc_env let local_opts = getOptions dflags buf src_fn (dflags', leftovers, warns) <- parseDynamicFilePragma dflags local_opts checkProcessArgsResult leftovers handleFlagWarnings dflags' warns let needs_preprocessing | Just (Unlit _) <- mb_phase = True | Nothing <- mb_phase, Unlit _ <- startPhase src_fn = True -- note: local_opts is only required if there's no Unlit phase | xopt Opt_Cpp dflags' = True | dopt Opt_Pp dflags' = True | otherwise = False when needs_preprocessing $ ghcError (ProgramError "buffer needs preprocesing; interactive check disabled") return (dflags', src_fn, buf) ----------------------------------------------------------------------------- -- Error messages ----------------------------------------------------------------------------- noModError :: DynFlags -> SrcSpan -> ModuleName -> FindResult -> IO ab -- ToDo: we don't have a proper line number for this error noModError dflags loc wanted_mod err = throwOneError $ mkPlainErrMsg loc $ cannotFindModule dflags wanted_mod err noHsFileErr :: SrcSpan -> String -> IO a noHsFileErr loc path = throwOneError $ mkPlainErrMsg loc $ text "Can't find" <+> text path packageModErr :: ModuleName -> IO a packageModErr mod = throwOneError $ mkPlainErrMsg noSrcSpan $ text "module" <+> quotes (ppr mod) <+> text "is a package module" multiRootsErr :: [ModSummary] -> IO () multiRootsErr [] = panic "multiRootsErr" multiRootsErr summs@(summ1:_) = throwOneError $ mkPlainErrMsg noSrcSpan $ text "module" <+> quotes (ppr mod) <+> text "is defined in multiple files:" <+> sep (map text files) where mod = ms_mod summ1 files = map (expectJust "checkDup" . ml_hs_file . ms_location) summs cyclicModuleErr :: [ModSummary] -> SDoc -- From a strongly connected component we find -- a single cycle to report cyclicModuleErr mss = ASSERT( not (null mss) ) case findCycle graph of Nothing -> ptext (sLit "Unexpected non-cycle") <+> ppr mss Just path -> vcat [ ptext (sLit "Module imports form a cycle:") , nest 2 (show_path path) ] where graph :: [Node NodeKey ModSummary] graph = [(ms, msKey ms, get_deps ms) | ms <- mss] get_deps :: ModSummary -> [NodeKey] get_deps ms = ([ (unLoc m, HsBootFile) | m <- ms_home_srcimps ms ] ++ [ (unLoc m, HsSrcFile) | m <- ms_home_imps ms ]) show_path [] = panic "show_path" show_path [m] = ptext (sLit "module") <+> ppr_ms m <+> ptext (sLit "imports itself") show_path (m1:m2:ms) = vcat ( nest 7 (ptext (sLit "module") <+> ppr_ms m1) : nest 6 (ptext (sLit "imports") <+> ppr_ms m2) : go ms ) where go [] = [ptext (sLit "which imports") <+> ppr_ms m1] go (m:ms) = (ptext (sLit "which imports") <+> ppr_ms m) : go ms ppr_ms :: ModSummary -> SDoc ppr_ms ms = quotes (ppr (moduleName (ms_mod ms))) <+> (parens (text (msHsFilePath ms)))