import Data.Dynamic
import Control.Monad
import Foreign
+import Foreign.C
import GHC.Exts
import Data.Array
import Control.Exception as Exception
= RunOk [Name] -- ^ names bound by this evaluation
| RunFailed -- ^ statement failed compilation
| RunException Exception -- ^ statement raised an exception
- | RunBreak ThreadId [Name] BreakInfo
+ | RunBreak ThreadId [Name] (Maybe BreakInfo)
data Status
- = Break HValue BreakInfo ThreadId
- -- ^ the computation hit a breakpoint
+ = Break Bool HValue BreakInfo ThreadId
+ -- ^ the computation hit a breakpoint (Bool <=> was an exception)
| Complete (Either Exception [HValue])
-- ^ the computation completed with either an exception or a value
resumeFinalIds :: [Id], -- [Id] to bind on completion
resumeApStack :: HValue, -- The object from which we can get
-- value of the free variables.
- resumeBreakInfo :: BreakInfo, -- the breakpoint we stopped at.
+ resumeBreakInfo :: Maybe BreakInfo,
+ -- the breakpoint we stopped at
+ -- (Nothing <=> exception)
resumeSpan :: SrcSpan, -- just a cache, otherwise it's a pain
-- to fetch the ModDetails & ModBreaks
-- to get this.
Just hmi -> return (modBreaks_locs (md_modBreaks (hm_details hmi)) ! num)
_ -> panic "getHistorySpan"
-{-
- [Main.hs:42:(1,0)-(3,52)] *Main> :history 2
- Foo.hs:1:3-5
- Bar.hs:5:23-48
- [Main.hs:42:(1,0)-(3,52)] *Main> :back
- Logged breakpoint at Foo.hs:1:3-5
- x :: Int
- y :: a
- _result :: [Char]
- [-1: Foo.hs:1:3-5] *Main> :back
- Logged breakpoint at Bar.hs:5:23-48
- z :: a
- _result :: Float
- [-2: Bar.hs:5:23-48] *Main> :forward
- Logged breakpoint at Foo.hs:1:3-5
- x :: Int
- y :: a
- _result :: [Char]
- [-1: Foo.hs:1:3-5] *Main> :cont
- .. continues
--}
-
-- | Run a statement in the current interactive context. Statement
-- may bind multple values.
runStmt :: Session -> String -> SingleStep -> IO RunResult
Nothing -> return RunFailed
Just (ids, hval) -> do
- when (isStep step) $ setStepFlag
-
- -- set the onBreakAction to be performed when we hit a
- -- breakpoint this is visible in the Byte Code
- -- Interpreter, thus it is a global variable,
- -- implemented with stable pointers
- withBreakAction breakMVar statusMVar $ do
+ withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
let thing_to_run = unsafeCoerce# hval :: IO [HValue]
status <- sandboxIO statusMVar thing_to_run
history =
case status of
-- did we hit a breakpoint or did we complete?
- (Break apStack info tid) -> do
+ (Break is_exception apStack info tid) -> do
hsc_env <- readIORef ref
- (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env apStack info
+ let mb_info | is_exception = Nothing
+ | otherwise = Just info
+ (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
+ apStack mb_info
let
resume = Resume expr tid breakMVar statusMVar
- bindings final_ids apStack info span
+ bindings final_ids apStack mb_info span
(toListBL history) 0
hsc_env2 = pushResume hsc_env1 resume
--
writeIORef ref hsc_env2
- return (RunBreak tid names info)
+ return (RunBreak tid names mb_info)
(Complete either_hvals) ->
case either_hvals of
Left e -> return (RunException e)
case status of
-- when tracing, if we hit a breakpoint that is not explicitly
-- enabled, then we just log the event in the history and continue.
- (Break apStack info tid) -> do
+ (Break is_exception apStack info tid) | not is_exception -> do
b <- isBreakEnabled hsc_env info
if b
then handle_normally
-- probably better make history strict here, otherwise
-- our BoundedList will be pointless.
evaluate history'
- setStepFlag
- status <- withBreakAction breakMVar statusMVar $ do
+ status <- withBreakAction True (hsc_dflags hsc_env)
+ breakMVar statusMVar $ do
withInterruptsSentTo
(do putMVar breakMVar () -- awaken the stopped thread
return tid)
return False
-foreign import ccall "rts_setStepFlag" setStepFlag :: IO ()
+foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
+foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
+
+setStepFlag = poke stepFlag 1
+resetStepFlag = poke stepFlag 0
-- this points to the IO action that is executed when a breakpoint is hit
-foreign import ccall "&breakPointIOAction"
- breakPointIOAction :: Ptr (StablePtr (BreakInfo -> HValue -> IO ()))
+foreign import ccall "&rts_breakpoint_io_action"
+ breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
-- When running a computation, we redirect ^C exceptions to the running
-- thread. ToDo: we might want a way to continue even if the target
sandboxIO :: MVar Status -> IO [HValue] -> IO Status
sandboxIO statusMVar thing =
withInterruptsSentTo
- (forkIO (do res <- Exception.try thing
+ (forkIO (do res <- Exception.try (rethrow thing)
putMVar statusMVar (Complete res)))
(takeMVar statusMVar)
+-- We want to turn ^C into a break when -fbreak-on-exception is on,
+-- but it's an async exception and we only break for sync exceptions.
+-- Idea: if we catch and re-throw it, then the re-throw will trigger
+-- a break. Great - but we don't want to re-throw all exceptions, because
+-- then we'll get a double break for ordinary sync exceptions (you'd have
+-- to :continue twice, which looks strange). So if the exception is
+-- not "Interrupted", we unset the exception flag before throwing.
+--
+rethrow :: IO a -> IO a
+rethrow io = Exception.catch io $ \e -> -- NB. not catchDyn
+ case e of
+ DynException d | Just Interrupted <- fromDynamic d
+ -> Exception.throwIO e
+ _ -> do poke exceptionFlag 0; Exception.throwIO e
+
+
withInterruptsSentTo :: IO ThreadId -> IO r -> IO r
withInterruptsSentTo io get_result = do
ts <- takeMVar interruptTargetThread
putMVar interruptTargetThread (child:ts)
get_result `finally` modifyMVar_ interruptTargetThread (return.tail)
-withBreakAction breakMVar statusMVar io
+-- This function sets up the interpreter for catching breakpoints, and
+-- resets everything when the computation has stopped running. This
+-- is a not-very-good way to ensure that only the interactive
+-- evaluation should generate breakpoints.
+withBreakAction step dflags breakMVar statusMVar io
= bracket setBreakAction resetBreakAction (\_ -> io)
where
setBreakAction = do
stablePtr <- newStablePtr onBreak
poke breakPointIOAction stablePtr
+ when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
+ when step $ setStepFlag
return stablePtr
+ -- Breaking on exceptions is not enabled by default, since it
+ -- might be a bit surprising. The exception flag is turned off
+ -- as soon as it is hit, or in resetBreakAction below.
- onBreak info apStack = do
+ onBreak is_exception info apStack = do
tid <- myThreadId
- putMVar statusMVar (Break apStack info tid)
+ putMVar statusMVar (Break is_exception apStack info tid)
takeMVar breakMVar
resetBreakAction stablePtr = do
poke breakPointIOAction noBreakStablePtr
+ poke exceptionFlag 0
+ resetStepFlag
freeStablePtr stablePtr
noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
-noBreakAction info apStack = putStrLn "*** Ignoring breakpoint"
+
+noBreakAction False info apStack = putStrLn "*** Ignoring breakpoint"
+noBreakAction True info apStack = return () -- exception: just continue
resume :: Session -> SingleStep -> IO RunResult
resume (Session ref) step
case r of
Resume expr tid breakMVar statusMVar bindings
final_ids apStack info _ _ _ -> do
- withBreakAction breakMVar statusMVar $ do
+ withBreakAction (isStep step) (hsc_dflags hsc_env)
+ breakMVar statusMVar $ do
status <- withInterruptsSentTo
(do putMVar breakMVar ()
-- this awakens the stopped thread...
history = resumeHistory r
new_ix = fn ix
--
- when (new_ix >= length history) $
+ when (new_ix > length history) $
throwDyn (ProgramError "no more logged breakpoints")
when (new_ix < 0) $
throwDyn (ProgramError "already at the beginning of the history")
let
- update_ic apStack info = do
+ update_ic apStack mb_info = do
(hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
- apStack info
+ apStack mb_info
let ic = hsc_IC hsc_env1
r' = r { resumeHistoryIx = new_ix }
ic' = ic { ic_resume = r':rs }
if new_ix == 0
then case r of
Resume { resumeApStack = apStack,
- resumeBreakInfo = info } ->
- update_ic apStack info
+ resumeBreakInfo = mb_info } ->
+ update_ic apStack mb_info
else case history !! (new_ix - 1) of
History apStack info ->
- update_ic apStack info
+ update_ic apStack (Just info)
-- -----------------------------------------------------------------------------
-- After stopping at a breakpoint, add free variables to the environment
bindLocalsAtBreakpoint
:: HscEnv
-> HValue
- -> BreakInfo
+ -> Maybe BreakInfo
-> IO (HscEnv, [Name], SrcSpan)
-bindLocalsAtBreakpoint hsc_env apStack info = do
+
+-- Nothing case: we stopped when an exception was raised, not at a
+-- breakpoint. We have no location information or local variables to
+-- bind, all we can do is bind a local variable to the exception
+-- value.
+bindLocalsAtBreakpoint hsc_env apStack Nothing = do
+ let exn_fs = FSLIT("_exception")
+ exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
+ e_fs = FSLIT("e")
+ e_name = mkInternalName (getUnique e_fs) (mkTyVarOcc e_fs) span
+ e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
+ exn_id = Id.mkGlobalId VanillaGlobal exn_name (mkTyVarTy e_tyvar)
+ vanillaIdInfo
+ new_tyvars = unitVarSet e_tyvar
+
+ ictxt0 = hsc_IC hsc_env
+ ictxt1 = extendInteractiveContext ictxt0 [exn_id] new_tyvars
+
+ span = mkGeneralSrcSpan FSLIT("<exception thrown>")
+ --
+ Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
+ return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
+
+-- Just case: we stopped at a breakpoint, we have information about the location
+-- of the breakpoint and the free variables of the expression.
+bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
let
mod_name = moduleName (breakInfo_module info)
-- _result in scope at any time.
let result_fs = FSLIT("_result")
result_name = mkInternalName (getUnique result_fs)
- (mkVarOccFS result_fs) (srcSpanStart span)
- result_id = Id.mkLocalId result_name result_ty
+ (mkVarOccFS result_fs) span
+ result_id = Id.mkGlobalId VanillaGlobal result_name result_ty
+ vanillaIdInfo
-- for each Id we're about to bind in the local envt:
-- - skolemise the type variables in its type, so they can't
mkNewId :: OccName -> Id -> IO Id
mkNewId occ id = do
let uniq = idUnique id
- loc = nameSrcLoc (idName id)
+ loc = nameSrcSpan (idName id)
name = mkInternalName uniq occ loc
ty = idType id
new_id = Id.mkGlobalId VanillaGlobal name ty (idInfo id)
resume = ic_resume ic
case resume of
[] -> return False
- _:rs -> do
+ r:rs -> do
writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = rs } }
+ abandon_ r
return True
abandonAll :: Session -> IO Bool
let ic = hsc_IC hsc_env
resume = ic_resume ic
case resume of
- [] -> return False
- _:rs -> do
+ [] -> return False
+ rs -> do
writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = [] } }
+ mapM_ abandon_ rs
return True
+-- when abandoning a computation we have to
+-- (a) kill the thread with an async exception, so that the
+-- computation itself is stopped, and
+-- (b) fill in the MVar. This step is necessary because any
+-- thunks that were under evaluation will now be updated
+-- with the partial computation, which still ends in takeMVar,
+-- so any attempt to evaluate one of these thunks will block
+-- unless we fill in the MVar.
+-- See test break010.
+abandon_ :: Resume -> IO ()
+abandon_ r = do
+ killThread (resumeThreadId r)
+ putMVar (resumeBreakMVar r) ()
+
-- -----------------------------------------------------------------------------
-- Bounded list, optimised for repeated cons
nameSetToGlobalRdrEnv :: NameSet -> ModuleName -> GlobalRdrEnv
nameSetToGlobalRdrEnv names mod =
- mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = vanillaProv mod }
+ mkGlobalRdrEnv [ GRE { gre_name = name, gre_par = NoParent, gre_prov = vanillaProv mod }
| name <- nameSetToList names ]
vanillaProv :: ModuleName -> Provenance
obtainTerm1 :: Session -> Bool -> Maybe Type -> a -> IO Term
obtainTerm1 sess force mb_ty x = withSession sess $ \hsc_env -> cvObtainTerm hsc_env force mb_ty (unsafeCoerce# x)
-obtainTerm :: Session -> Bool -> Id -> IO (Maybe Term)
+obtainTerm :: Session -> Bool -> Id -> IO Term
obtainTerm sess force id = withSession sess $ \hsc_env -> do
- mb_v <- Linker.getHValue (varName id)
- case mb_v of
- Just v -> fmap Just$ cvObtainTerm hsc_env force (Just$ idType id) v
- Nothing -> return Nothing
+ hv <- Linker.getHValue hsc_env (varName id)
+ cvObtainTerm hsc_env force (Just$ idType id) hv
#endif /* GHCI */
projects / ghc-hetmet.git / blobdiff