diff options
| -rw-r--r-- | compiler/ghci/RtClosureInspect.hs | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/compiler/ghci/RtClosureInspect.hs b/compiler/ghci/RtClosureInspect.hs index 95ae5acd02..e39a0bc7e3 100644 --- a/compiler/ghci/RtClosureInspect.hs +++ b/compiler/ghci/RtClosureInspect.hs @@ -654,11 +654,13 @@ cvObtainTerm hsc_env max_depth force old_ty hval = runTR hsc_env $ do clos <- trIO $ getClosureData a case tipe clos of -- Thunks we may want to force --- NB. this won't attempt to force a BLACKHOLE. Even with :force, we never --- force blackholes, because it would almost certainly result in deadlock, --- and showing the '_' is more useful. t | isThunk t && force -> traceTR (text "Forcing a " <> text (show t)) >> seq a (go (pred max_depth) my_ty old_ty a) +-- Blackholes are indirections iff the payload is not TSO or BLOCKING_QUEUE. So we +-- treat them like indirections; if the payload is TSO or BLOCKING_QUEUE, we'll end up +-- showing '_' which is what we want. + Blackhole -> do traceTR (text "Following a BLACKHOLE") + appArr (go max_depth my_ty old_ty) (ptrs clos) 0 -- We always follow indirections Indirection i -> do traceTR (text "Following an indirection" <> parens (int i) ) go max_depth my_ty old_ty $! (ptrs clos ! 0) @@ -817,6 +819,7 @@ cvReconstructType hsc_env max_depth old_ty hval = runTR_maybe hsc_env $ do go my_ty a = do clos <- trIO $ getClosureData a case tipe clos of + Blackhole -> appArr (go my_ty) (ptrs clos) 0 -- carefully, don't eval the TSO Indirection _ -> go my_ty $! (ptrs clos ! 0) MutVar _ -> do contents <- trIO$ IO$ \w -> readMutVar# (unsafeCoerce# a) w |