-- Name-cache stuff
allocateGlobalBinder, initNameCache,
- getNameCache, setNameCache
+ getNameCache, lockedUpdNameCache,
) where
#include "HsVersions.h"
import MkId
import Outputable
+import Exception ( onException )
+
+import Control.Concurrent.MVar ( tryTakeMVar, takeMVar, putMVar )
\end{code}
-- moment when we know its Module and SrcLoc in their full glory
newGlobalBinder mod occ loc
- = do { mod `seq` occ `seq` return () -- See notes with lookupOrig_help
--- ; traceIf (text "newGlobalBinder" <+> ppr mod <+> ppr occ <+> ppr loc)
- ; name_supply <- getNameCache
- ; let (name_supply', name) = allocateGlobalBinder
- name_supply mod occ
- loc
- ; setNameCache name_supply'
- ; return name }
+ = do mod `seq` occ `seq` return () -- See notes with lookupOrig
+-- traceIf (text "newGlobalBinder" <+> ppr mod <+> ppr occ <+> ppr loc)
+ updNameCache $ \name_cache ->
+ allocateGlobalBinder name_cache mod occ loc
allocateGlobalBinder
:: NameCache
-- This did happen, with tycon_mod in TcIface.tcIfaceAlt (DataAlt..)
mod `seq` occ `seq` return ()
-- ; traceIf (text "lookup_orig" <+> ppr mod <+> ppr occ)
-
- ; name_cache <- getNameCache
- ; case lookupOrigNameCache (nsNames name_cache) mod occ of {
- Just name -> return name;
+
+ ; updNameCache $ \name_cache ->
+ case lookupOrigNameCache (nsNames name_cache) mod occ of {
+ Just name -> (name_cache, name);
Nothing ->
let
us = nsUniqs name_cache
new_cache = extendNameCache (nsNames name_cache) mod occ name
in
case splitUniqSupply us of { (us',_) -> do
- setNameCache name_cache{ nsUniqs = us', nsNames = new_cache }
- return name
+ (name_cache{ nsUniqs = us', nsNames = new_cache }, name)
}}}
newIPName :: IPName OccName -> TcRnIf m n (IPName Name)
-newIPName occ_name_ip = do
- name_supply <- getNameCache
+newIPName occ_name_ip =
+ updNameCache $ \name_cache ->
let
- ipcache = nsIPs name_supply
+ ipcache = nsIPs name_cache
+ key = occ_name_ip -- Ensures that ?x and %x get distinct Names
+ in
case lookupFM ipcache key of
- Just name_ip -> return name_ip
- Nothing -> do setNameCache new_ns
- return name_ip
- where
- (us', us1) = splitUniqSupply (nsUniqs name_supply)
- uniq = uniqFromSupply us1
- name_ip = mapIPName (mkIPName uniq) occ_name_ip
- new_ipcache = addToFM ipcache key name_ip
- new_ns = name_supply {nsUniqs = us', nsIPs = new_ipcache}
- where
- key = occ_name_ip -- Ensures that ?x and %x get distinct Names
+ Just name_ip -> (name_cache, name_ip)
+ Nothing -> (new_ns, name_ip)
+ where
+ (us', us1) = splitUniqSupply (nsUniqs name_cache)
+ uniq = uniqFromSupply us1
+ name_ip = mapIPName (mkIPName uniq) occ_name_ip
+ new_ipcache = addToFM ipcache key name_ip
+ new_ns = name_cache {nsUniqs = us', nsIPs = new_ipcache}
\end{code}
%************************************************************************
getNameCache = do { HscEnv { hsc_NC = nc_var } <- getTopEnv;
readMutVar nc_var }
-setNameCache :: NameCache -> TcRnIf a b ()
-setNameCache nc = do { HscEnv { hsc_NC = nc_var } <- getTopEnv;
- writeMutVar nc_var nc }
+updNameCache :: (NameCache -> (NameCache, c)) -> TcRnIf a b c
+updNameCache upd_fn = do
+ HscEnv { hsc_NC = nc_var } <- getTopEnv
+ atomicUpdMutVar' nc_var upd_fn
+
+-- | Update the name cache, but takes a lock while the update function is
+-- running. If the update function throws an exception the lock is released
+-- and the exception propagated.
+lockedUpdNameCache :: (NameCache -> IO (NameCache, c)) -> TcRnIf a b c
+lockedUpdNameCache upd_fn = do
+ lock <- hsc_NC_lock `fmap` getTopEnv
+ -- Non-blocking "takeMVar" so we can show diagnostics if we didn't get the
+ -- lock.
+ mb_ok <- liftIO $ tryTakeMVar lock
+ case mb_ok of
+ Nothing -> do
+ traceIf (text "lockedUpdNameCache: failed to take lock. blocking..")
+ _ <- liftIO $ takeMVar lock
+ traceIf (text "lockedUpdNameCache: got lock")
+ Just _ -> return ()
+
+ name_cache <- getNameCache
+ (name_cache', rslt) <- liftIO (upd_fn name_cache
+ `onException` putMVar lock ())
+
+ nc_var <- hsc_NC `fmap` getTopEnv
+ writeMutVar nc_var $! name_cache'
+
+ liftIO (putMVar lock ())
+ return rslt
\end{code}