module InteractiveEval (
#ifdef GHCI
- RunResult(..), Status(..), Resume(..),
- runStmt, stepStmt, -- traceStmt,
- resume, stepResume, -- traceResume,
+ RunResult(..), Status(..), Resume(..), History(..),
+ runStmt, SingleStep(..),
+ resume,
abandon, abandonAll,
getResumeContext,
+ getHistorySpan,
+ back, forward,
setContext, getContext,
nameSetToGlobalRdrEnv,
getNamesInScope,
import Panic
import UniqFM
import Maybes
+import ErrUtils
import Util
import SrcLoc
+import BreakArray
import RtClosureInspect
import Packages
import BasicTypes
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.
- resumeSpan :: SrcSpan -- just a cache, otherwise it's a pain
+ 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.
+ resumeHistory :: [History],
+ resumeHistoryIx :: Int -- 0 <==> at the top of the history
}
getResumeContext :: Session -> IO [Resume]
isStep RunToCompletion = False
isStep _ = True
--- type History = [HistoryItem]
---
--- data HistoryItem = HistoryItem HValue BreakInfo
---
--- historyBreakInfo :: HistoryItem -> BreakInfo
--- historyBreakInfo (HistoryItem _ bi) = bi
---
--- setContextToHistoryItem :: Session -> HistoryItem -> IO ()
--- setContextToHistoryItem
-
--- We need to track two InteractiveContexts:
--- - the IC before runStmt, which is restored on each resume
--- - the IC binding the results of the original statement, which
--- will be the IC when runStmt returns with RunOk.
+data History
+ = History {
+ historyApStack :: HValue,
+ historyBreakInfo :: BreakInfo
+ }
+
+getHistorySpan :: Session -> History -> IO SrcSpan
+getHistorySpan s hist = withSession s $ \hsc_env -> do
+ let inf = historyBreakInfo hist
+ num = breakInfo_number inf
+ case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
+ Just hmi -> return (modBreaks_locs (md_modBreaks (hm_details hmi)) ! num)
+ _ -> panic "getHistorySpan"
-- | Run a statement in the current interactive context. Statement
-- may bind multple values.
-runStmt :: Session -> String -> IO RunResult
-runStmt session expr = runStmt_ session expr RunToCompletion
-
--- | Run a statement, stopping at the first breakpoint location encountered
--- (regardless of whether the breakpoint is enabled).
-stepStmt :: Session -> String -> IO RunResult
-stepStmt session expr = runStmt_ session expr SingleStep
-
--- | Run a statement, logging breakpoints passed, and stopping when either
--- an enabled breakpoint is reached, or the statement completes.
--- traceStmt :: Session -> String -> IO (RunResult, History)
--- traceStmt session expr = runStmt_ session expr RunAndLogSteps
-
-runStmt_ (Session ref) expr step
+runStmt :: Session -> String -> SingleStep -> IO RunResult
+runStmt (Session ref) expr step
= do
hsc_env <- readIORef ref
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
let ic = hsc_IC hsc_env
bindings = (ic_tmp_ids ic, ic_tyvars ic)
- handleRunStatus expr ref bindings ids breakMVar statusMVar status
-handleRunStatus expr ref bindings final_ids breakMVar statusMVar status =
+ case step of
+ RunAndLogSteps ->
+ traceRunStatus expr ref bindings ids
+ breakMVar statusMVar status emptyHistory
+ _other ->
+ handleRunStatus expr ref bindings ids
+ breakMVar statusMVar status emptyHistory
+
+
+emptyHistory = nilBL 50 -- keep a log of length 50
+
+handleRunStatus expr ref bindings final_ids breakMVar statusMVar status
+ 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
- let
- mod_name = moduleName (breakInfo_module info)
- mod_details = fmap hm_details (lookupUFM (hsc_HPT hsc_env) mod_name)
- breaks = md_modBreaks (expectJust "handlRunStatus" mod_details)
- --
+ let mb_info | is_exception = Nothing
+ | otherwise = Just info
(hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
- apStack info breaks
+ 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)
Linker.extendLinkEnv (zip final_names hvals)
return (RunOk final_names)
-{-
-traceRunStatus ref final_ids
+
+traceRunStatus expr ref bindings final_ids
breakMVar statusMVar status history = do
hsc_env <- readIORef ref
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) | not (isBreakEnabled hsc_env info) -> do
- let history' = consBL (apStack,info) history
- withBreakAction breakMVar statusMVar $ do
- status <- withInterruptsSentTo
- (do putMVar breakMVar () -- this awakens the stopped thread...
- return tid)
- (takeMVar statusMVar) -- and wait for the result
-
- traceRunStatus ref final_ids
- breakMVar statusMVar status history'
+ (Break is_exception apStack info tid) | not is_exception -> do
+ b <- isBreakEnabled hsc_env info
+ if b
+ then handle_normally
+ else do
+ let history' = consBL (History apStack info) history
+ -- probably better make history strict here, otherwise
+ -- our BoundedList will be pointless.
+ evaluate history'
+ status <- withBreakAction True (hsc_dflags hsc_env)
+ breakMVar statusMVar $ do
+ withInterruptsSentTo
+ (do putMVar breakMVar () -- awaken the stopped thread
+ return tid)
+ (takeMVar statusMVar) -- and wait for the result
+ traceRunStatus expr ref bindings final_ids
+ breakMVar statusMVar status history'
_other ->
- handleRunStatus ref final_ids
- breakMVar statusMVar status
-
--}
+ handle_normally
+ where
+ handle_normally = handleRunStatus expr ref bindings final_ids
+ breakMVar statusMVar status history
+
+
+isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
+isBreakEnabled hsc_env inf =
+ case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
+ Just hmi -> do
+ w <- getBreak (modBreaks_flags (md_modBreaks (hm_details hmi)))
+ (breakInfo_number inf)
+ case w of Just n -> return (n /= 0); _other -> return False
+ _ ->
+ 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)
+-- | this just re-throws any exceptions received. The point of this
+-- is that if -fbreak-on-excepsions is on, we only get a chance to break
+-- for synchronous exceptions, and this turns an async exception into
+-- a sync exception, so for instance a ^C exception will break right here
+-- unless it is caught elsewhere.
+rethrow :: IO a -> IO a
+rethrow io = Exception.catch io Exception.throwIO
+
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"
-
-resume :: Session -> IO RunResult
-resume session = resume_ session RunToCompletion
-stepResume :: Session -> IO RunResult
-stepResume session = resume_ session SingleStep
+noBreakAction False info apStack = putStrLn "*** Ignoring breakpoint"
+noBreakAction True info apStack = return () -- exception: just continue
--- traceResume :: Session -> IO RunResult
--- traceResume session handle = resume_ session handle RunAndLogSteps
-
-resume_ :: Session -> SingleStep -> IO RunResult
-resume_ (Session ref) step
+resume :: Session -> SingleStep -> IO RunResult
+resume (Session ref) step
= do
hsc_env <- readIORef ref
let ic = hsc_IC hsc_env
(ic_tmp_ids ic))
Linker.deleteFromLinkEnv new_names
-
when (isStep step) $ setStepFlag
case r of
Resume expr tid breakMVar statusMVar bindings
- final_ids apStack info _ -> do
- withBreakAction breakMVar statusMVar $ do
+ final_ids apStack info _ _ _ -> do
+ withBreakAction (isStep step) (hsc_dflags hsc_env)
+ breakMVar statusMVar $ do
status <- withInterruptsSentTo
(do putMVar breakMVar ()
-- this awakens the stopped thread...
return tid)
(takeMVar statusMVar)
-- and wait for the result
- handleRunStatus expr ref bindings final_ids
- breakMVar statusMVar status
+ case step of
+ RunAndLogSteps ->
+ traceRunStatus expr ref bindings final_ids
+ breakMVar statusMVar status emptyHistory
+ _other ->
+ handleRunStatus expr ref bindings final_ids
+ breakMVar statusMVar status emptyHistory
+
+
+back :: Session -> IO ([Name], Int, SrcSpan)
+back = moveHist (+1)
+
+forward :: Session -> IO ([Name], Int, SrcSpan)
+forward = moveHist (subtract 1)
+
+moveHist fn (Session ref) = do
+ hsc_env <- readIORef ref
+ case ic_resume (hsc_IC hsc_env) of
+ [] -> throwDyn (ProgramError "not stopped at a breakpoint")
+ (r:rs) -> do
+ let ix = resumeHistoryIx r
+ history = resumeHistory r
+ new_ix = fn ix
+ --
+ 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 mb_info = do
+ (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
+ apStack mb_info
+ let ic = hsc_IC hsc_env1
+ r' = r { resumeHistoryIx = new_ix }
+ ic' = ic { ic_resume = r':rs }
+
+ writeIORef ref hsc_env1{ hsc_IC = ic' }
+
+ return (names, new_ix, span)
+
+ -- careful: we want apStack to be the AP_STACK itself, not a thunk
+ -- around it, hence the cases are carefully constructed below to
+ -- make this the case. ToDo: this is v. fragile, do something better.
+ if new_ix == 0
+ then case r of
+ Resume { resumeApStack = apStack,
+ resumeBreakInfo = mb_info } ->
+ update_ic apStack mb_info
+ else case history !! (new_ix - 1) of
+ History apStack info ->
+ update_ic apStack (Just info)
-- -----------------------------------------------------------------------------
-- After stopping at a breakpoint, add free variables to the environment
bindLocalsAtBreakpoint
:: HscEnv
-> HValue
- -> BreakInfo
- -> ModBreaks
+ -> Maybe BreakInfo
-> IO (HscEnv, [Name], SrcSpan)
-bindLocalsAtBreakpoint hsc_env apStack info breaks = 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)
+ mod_details = fmap hm_details (lookupUFM (hsc_HPT hsc_env) mod_name)
+ breaks = md_modBreaks (expectJust "handlRunStatus" mod_details)
index = breakInfo_number info
vars = breakInfo_vars info
result_ty = breakInfo_resty info
| otherwise = False
let (ids, offsets) = unzip pointers
- hValues <- mapM (getIdValFromApStack apStack) offsets
- new_ids <- zipWithM mkNewId occs ids
- let names = map idName ids
+
+ -- It might be that getIdValFromApStack fails, because the AP_STACK
+ -- has been accidentally evaluated, or something else has gone wrong.
+ -- So that we don't fall over in a heap when this happens, just don't
+ -- bind any free variables instead, and we emit a warning.
+ mb_hValues <- mapM (getIdValFromApStack apStack) offsets
+ let filtered_ids = [ id | (id, Just _) <- zip ids mb_hValues ]
+ when (any isNothing mb_hValues) $
+ debugTraceMsg (hsc_dflags hsc_env) 1 $
+ text "Warning: _result has been evaluated, some bindings have been lost"
+
+ new_ids <- zipWithM mkNewId occs filtered_ids
+ let names = map idName new_ids
-- make an Id for _result. We use the Unique of the FastString "_result";
-- we don't care about uniqueness here, because there will only be one
-- _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
-- - tidy the type variables
-- - globalise the Id (Ids are supposed to be Global, apparently).
--
- let all_ids | isPointer result_id = result_id : ids
- | otherwise = ids
+ let all_ids | isPointer result_id = result_id : new_ids
+ | otherwise = new_ids
(id_tys, tyvarss) = mapAndUnzip (skolemiseTy.idType) all_ids
(_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
new_tyvars = unionVarSets tyvarss
- new_ids = zipWith setIdType all_ids tidy_tys
- global_ids = map (globaliseId VanillaGlobal) new_ids
+ final_ids = zipWith setIdType all_ids tidy_tys
let ictxt0 = hsc_IC hsc_env
- ictxt1 = extendInteractiveContext ictxt0 global_ids new_tyvars
+ ictxt1 = extendInteractiveContext ictxt0 final_ids new_tyvars
- Linker.extendLinkEnv (zip names hValues)
+ Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
return (hsc_env{ hsc_IC = ictxt1 }, result_name:names, span)
where
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 = tidyTopType (idType id)
+ ty = idType id
new_id = Id.mkGlobalId VanillaGlobal name ty (idInfo id)
return new_id
skolemiseTyVar tyvar = mkTcTyVar (tyVarName tyvar) (tyVarKind tyvar)
(SkolemTv RuntimeUnkSkol)
--- Todo: turn this into a primop, and provide special version(s) for
--- unboxed things
-foreign import ccall unsafe "rts_getApStackVal"
- getApStackVal :: StablePtr a -> Int -> IO (StablePtr b)
-
-getIdValFromApStack :: a -> Int -> IO HValue
-getIdValFromApStack apStack stackDepth = do
- apSptr <- newStablePtr apStack
- resultSptr <- getApStackVal apSptr (stackDepth - 1)
- result <- deRefStablePtr resultSptr
- freeStablePtr apSptr
- freeStablePtr resultSptr
- return (unsafeCoerce# result)
+getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
+getIdValFromApStack apStack (I# stackDepth) = do
+ case getApStackVal# apStack (stackDepth +# 1#) of
+ -- The +1 is magic! I don't know where it comes
+ -- from, but this makes things line up. --SDM
+ (# ok, result #) ->
+ case ok of
+ 0# -> return Nothing -- AP_STACK not found
+ _ -> return (Just (unsafeCoerce# result))
pushResume :: HscEnv -> Resume -> HscEnv
pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
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
[a] -- left
[a] -- right, list is (left ++ reverse right)
+nilBL :: Int -> BoundedList a
+nilBL bound = BL 0 bound [] []
+
consBL a (BL len bound left right)
| len < bound = BL (len+1) bound (a:left) right
- | null right = BL len bound [] $! tail (reverse left)
- | otherwise = BL len bound [] $! tail right
+ | null right = BL len bound [a] $! tail (reverse left)
+ | otherwise = BL len bound (a:left) $! tail right
toListBL (BL _ _ left right) = left ++ reverse right
-lenBL (BL len _ _ _) = len
+-- lenBL (BL len _ _ _) = len
-- -----------------------------------------------------------------------------
-- | Set the interactive evaluation context.
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