Flushing and uncaching a single module is not completely atomic since
both caches a cleared separately. However, flushing is only done when
changing the working directory which shouldn't be done concurrently to
other threads. Uncaching is only done in 'summariseModule' which
requires some more work to become thread-safe anyway.
import FiniteMap
import LazyUniqFM
import Maybes ( expectJust )
import FiniteMap
import LazyUniqFM
import Maybes ( expectJust )
+import Exception ( evaluate )
import Distribution.Text
import Distribution.Package hiding (PackageId)
import Distribution.Text
import Distribution.Package hiding (PackageId)
-import Data.IORef ( IORef, writeIORef, readIORef, modifyIORef )
+import Data.IORef ( IORef, writeIORef, readIORef, atomicModifyIORef )
import System.Directory
import System.FilePath
import Control.Monad
import System.Directory
import System.FilePath
import Control.Monad
-- assumed to not move around during a session.
flushFinderCaches :: HscEnv -> IO ()
flushFinderCaches hsc_env = do
-- assumed to not move around during a session.
flushFinderCaches :: HscEnv -> IO ()
flushFinderCaches hsc_env = do
+ -- Ideally the update to both caches be a single atomic operation.
writeIORef fc_ref emptyUFM
flushModLocationCache this_pkg mlc_ref
where
writeIORef fc_ref emptyUFM
flushModLocationCache this_pkg mlc_ref
where
flushModLocationCache :: PackageId -> IORef ModLocationCache -> IO ()
flushModLocationCache this_pkg ref = do
flushModLocationCache :: PackageId -> IORef ModLocationCache -> IO ()
flushModLocationCache this_pkg ref = do
- fm <- readIORef ref
- writeIORef ref $! filterFM is_ext fm
+ atomicModifyIORef ref $ \fm -> (filterFM is_ext fm, ())
+ _ <- evaluate =<< readIORef ref
return ()
where is_ext mod _ | modulePackageId mod /= this_pkg = True
| otherwise = False
addToFinderCache :: IORef FinderCache -> ModuleName -> FindResult -> IO ()
return ()
where is_ext mod _ | modulePackageId mod /= this_pkg = True
| otherwise = False
addToFinderCache :: IORef FinderCache -> ModuleName -> FindResult -> IO ()
-addToFinderCache ref key val = modifyIORef ref $ \c -> addToUFM c key val
+addToFinderCache ref key val =
+ atomicModifyIORef ref $ \c -> (addToUFM c key val, ())
addToModLocationCache :: IORef ModLocationCache -> Module -> ModLocation -> IO ()
addToModLocationCache :: IORef ModLocationCache -> Module -> ModLocation -> IO ()
-addToModLocationCache ref key val = modifyIORef ref $ \c -> addToFM c key val
+addToModLocationCache ref key val =
+ atomicModifyIORef ref $ \c -> (addToFM c key val, ())
removeFromFinderCache :: IORef FinderCache -> ModuleName -> IO ()
removeFromFinderCache :: IORef FinderCache -> ModuleName -> IO ()
-removeFromFinderCache ref key = modifyIORef ref $ \c -> delFromUFM c key
+removeFromFinderCache ref key =
+ atomicModifyIORef ref $ \c -> (delFromUFM c key, ())
removeFromModLocationCache :: IORef ModLocationCache -> Module -> IO ()
removeFromModLocationCache :: IORef ModLocationCache -> Module -> IO ()
-removeFromModLocationCache ref key = modifyIORef ref $ \c -> delFromFM c key
+removeFromModLocationCache ref key =
+ atomicModifyIORef ref $ \c -> (delFromFM c key, ())
lookupFinderCache :: IORef FinderCache -> ModuleName -> IO (Maybe FindResult)
lookupFinderCache ref key = do
lookupFinderCache :: IORef FinderCache -> ModuleName -> IO (Maybe FindResult)
lookupFinderCache ref key = do
-- | Inform GHC that the working directory has changed. GHC will flush
-- its cache of module locations, since it may no longer be valid.
-- | Inform GHC that the working directory has changed. GHC will flush
-- its cache of module locations, since it may no longer be valid.
--- Note: if you change the working directory, you should also unload
--- the current program (set targets to empty, followed by load).
+--
+-- Note: Before changing the working directory make sure all threads running
+-- in the same session have stopped. If you change the working directory,
+-- you should also unload the current program (set targets to empty,
+-- followed by load).
workingDirectoryChanged :: GhcMonad m => m ()
workingDirectoryChanged = withSession $ (liftIO . flushFinderCaches)
workingDirectoryChanged :: GhcMonad m => m ()
workingDirectoryChanged = withSession $ (liftIO . flushFinderCaches)