1 -- -----------------------------------------------------------------------------
3 -- (c) The University of Glasgow, 2005-2007
5 -- Running statements interactively
7 -- -----------------------------------------------------------------------------
9 module InteractiveEval (
11 RunResult(..), Status(..), Resume(..), History(..),
12 runStmt, SingleStep(..),
20 setContext, getContext,
21 nameSetToGlobalRdrEnv,
31 compileExpr, dynCompileExpr,
33 Term(..), obtainTerm, obtainTerm1, obtainTermB, reconstructType,
34 skolemiseSubst, skolemiseTy
40 #include "HsVersions.h"
42 import HscMain hiding (compileExpr)
45 import Type hiding (typeKind)
46 import TcType hiding (typeKind)
51 import Name hiding ( varName )
69 import RtClosureInspect
75 import Data.List (find)
82 import Control.Concurrent
83 import Data.List (sortBy)
85 import Foreign.StablePtr
87 -- -----------------------------------------------------------------------------
88 -- running a statement interactively
91 = RunOk [Name] -- ^ names bound by this evaluation
92 | RunFailed -- ^ statement failed compilation
93 | RunException SomeException -- ^ statement raised an exception
94 | RunBreak ThreadId [Name] (Maybe BreakInfo)
97 = Break Bool HValue BreakInfo ThreadId
98 -- ^ the computation hit a breakpoint (Bool <=> was an exception)
99 | Complete (Either SomeException [HValue])
100 -- ^ the computation completed with either an exception or a value
104 resumeStmt :: String, -- the original statement
105 resumeThreadId :: ThreadId, -- thread running the computation
106 resumeBreakMVar :: MVar (),
107 resumeStatMVar :: MVar Status,
108 resumeBindings :: ([Id], TyVarSet),
109 resumeFinalIds :: [Id], -- [Id] to bind on completion
110 resumeApStack :: HValue, -- The object from which we can get
111 -- value of the free variables.
112 resumeBreakInfo :: Maybe BreakInfo,
113 -- the breakpoint we stopped at
114 -- (Nothing <=> exception)
115 resumeSpan :: SrcSpan, -- just a cache, otherwise it's a pain
116 -- to fetch the ModDetails & ModBreaks
118 resumeHistory :: [History],
119 resumeHistoryIx :: Int -- 0 <==> at the top of the history
122 getResumeContext :: Session -> IO [Resume]
123 getResumeContext s = withSession s (return . ic_resume . hsc_IC)
130 isStep :: SingleStep -> Bool
131 isStep RunToCompletion = False
136 historyApStack :: HValue,
137 historyBreakInfo :: BreakInfo,
138 historyEnclosingDecl :: Id
139 -- ^^ A cache of the enclosing top level declaration, for convenience
142 mkHistory :: HscEnv -> HValue -> BreakInfo -> History
143 mkHistory hsc_env hval bi = let
144 h = History hval bi decl
145 decl = findEnclosingDecl hsc_env (getHistoryModule h)
146 (getHistorySpan hsc_env h)
149 getHistoryModule :: History -> Module
150 getHistoryModule = breakInfo_module . historyBreakInfo
152 getHistorySpan :: HscEnv -> History -> SrcSpan
153 getHistorySpan hsc_env hist =
154 let inf = historyBreakInfo hist
155 num = breakInfo_number inf
156 in case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
157 Just hmi -> modBreaks_locs (getModBreaks hmi) ! num
158 _ -> panic "getHistorySpan"
160 getModBreaks :: HomeModInfo -> ModBreaks
162 | Just linkable <- hm_linkable hmi,
163 [BCOs _ modBreaks] <- linkableUnlinked linkable
166 = emptyModBreaks -- probably object code
168 {- | Finds the enclosing top level function name -}
169 -- ToDo: a better way to do this would be to keep hold of the decl_path computed
170 -- by the coverage pass, which gives the list of lexically-enclosing bindings
172 findEnclosingDecl :: HscEnv -> Module -> SrcSpan -> Id
173 findEnclosingDecl hsc_env mod span =
174 case lookupUFM (hsc_HPT hsc_env) (moduleName mod) of
175 Nothing -> panic "findEnclosingDecl"
177 globals = typeEnvIds (md_types (hm_details hmi))
179 find (\id -> let n = idName id in
180 nameSrcSpan n < span && isExternalName n)
181 (reverse$ sortBy (compare `on` (nameSrcSpan.idName))
185 -- | Run a statement in the current interactive context. Statement
186 -- may bind multple values.
187 runStmt :: Session -> String -> SingleStep -> IO RunResult
188 runStmt (Session ref) expr step
190 hsc_env <- readIORef ref
192 breakMVar <- newEmptyMVar -- wait on this when we hit a breakpoint
193 statusMVar <- newEmptyMVar -- wait on this when a computation is running
195 -- Turn off -fwarn-unused-bindings when running a statement, to hide
196 -- warnings about the implicit bindings we introduce.
197 let dflags' = dopt_unset (hsc_dflags hsc_env) Opt_WarnUnusedBinds
198 hsc_env' = hsc_env{ hsc_dflags = dflags' }
200 maybe_stuff <- hscStmt hsc_env' expr
203 Nothing -> return RunFailed
204 Just (ids, hval) -> do
207 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
208 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
209 sandboxIO dflags' statusMVar thing_to_run
211 let ic = hsc_IC hsc_env
212 bindings = (ic_tmp_ids ic, ic_tyvars ic)
216 traceRunStatus expr ref bindings ids
217 breakMVar statusMVar status emptyHistory
219 handleRunStatus expr ref bindings ids
220 breakMVar statusMVar status emptyHistory
222 emptyHistory :: BoundedList History
223 emptyHistory = nilBL 50 -- keep a log of length 50
225 handleRunStatus :: String -> IORef HscEnv -> ([Id], TyVarSet) -> [Id]
226 -> MVar () -> MVar Status -> Status -> BoundedList History
228 handleRunStatus expr ref bindings final_ids breakMVar statusMVar status
231 -- did we hit a breakpoint or did we complete?
232 (Break is_exception apStack info tid) -> do
233 hsc_env <- readIORef ref
234 let mb_info | is_exception = Nothing
235 | otherwise = Just info
236 (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
239 resume = Resume expr tid breakMVar statusMVar
240 bindings final_ids apStack mb_info span
242 hsc_env2 = pushResume hsc_env1 resume
244 writeIORef ref hsc_env2
245 return (RunBreak tid names mb_info)
246 (Complete either_hvals) ->
248 Left e -> return (RunException e)
250 hsc_env <- readIORef ref
251 let final_ic = extendInteractiveContext (hsc_IC hsc_env)
252 final_ids emptyVarSet
253 -- the bound Ids never have any free TyVars
254 final_names = map idName final_ids
255 Linker.extendLinkEnv (zip final_names hvals)
256 hsc_env' <- rttiEnvironment hsc_env{hsc_IC=final_ic}
257 writeIORef ref hsc_env'
258 return (RunOk final_names)
260 traceRunStatus :: String -> IORef HscEnv -> ([Id], TyVarSet) -> [Id]
261 -> MVar () -> MVar Status -> Status -> BoundedList History
263 traceRunStatus expr ref bindings final_ids
264 breakMVar statusMVar status history = do
265 hsc_env <- readIORef ref
267 -- when tracing, if we hit a breakpoint that is not explicitly
268 -- enabled, then we just log the event in the history and continue.
269 (Break is_exception apStack info tid) | not is_exception -> do
270 b <- isBreakEnabled hsc_env info
274 let history' = mkHistory hsc_env apStack info `consBL` history
275 -- probably better make history strict here, otherwise
276 -- our BoundedList will be pointless.
278 status <- withBreakAction True (hsc_dflags hsc_env)
279 breakMVar statusMVar $ do
280 withInterruptsSentTo tid $ do
281 putMVar breakMVar () -- awaken the stopped thread
282 takeMVar statusMVar -- and wait for the result
283 traceRunStatus expr ref bindings final_ids
284 breakMVar statusMVar status history'
288 handle_normally = handleRunStatus expr ref bindings final_ids
289 breakMVar statusMVar status history
292 isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
293 isBreakEnabled hsc_env inf =
294 case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
296 w <- getBreak (modBreaks_flags (getModBreaks hmi))
297 (breakInfo_number inf)
298 case w of Just n -> return (n /= 0); _other -> return False
303 foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
304 foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
307 setStepFlag = poke stepFlag 1
308 resetStepFlag :: IO ()
309 resetStepFlag = poke stepFlag 0
311 -- this points to the IO action that is executed when a breakpoint is hit
312 foreign import ccall "&rts_breakpoint_io_action"
313 breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
315 -- When running a computation, we redirect ^C exceptions to the running
316 -- thread. ToDo: we might want a way to continue even if the target
317 -- thread doesn't die when it receives the exception... "this thread
318 -- is not responding".
320 -- Careful here: there may be ^C exceptions flying around, so we start the new
321 -- thread blocked (forkIO inherits block from the parent, #1048), and unblock
322 -- only while we execute the user's code. We can't afford to lose the final
323 -- putMVar, otherwise deadlock ensues. (#1583, #1922, #1946)
324 sandboxIO :: DynFlags -> MVar Status -> IO [HValue] -> IO Status
325 sandboxIO dflags statusMVar thing =
326 block $ do -- fork starts blocked
327 id <- forkIO $ do res <- Exception.try (unblock $ rethrow dflags thing)
328 putMVar statusMVar (Complete res) -- empty: can't block
329 withInterruptsSentTo id $ takeMVar statusMVar
332 -- We want to turn ^C into a break when -fbreak-on-exception is on,
333 -- but it's an async exception and we only break for sync exceptions.
334 -- Idea: if we catch and re-throw it, then the re-throw will trigger
335 -- a break. Great - but we don't want to re-throw all exceptions, because
336 -- then we'll get a double break for ordinary sync exceptions (you'd have
337 -- to :continue twice, which looks strange). So if the exception is
338 -- not "Interrupted", we unset the exception flag before throwing.
340 rethrow :: DynFlags -> IO a -> IO a
341 #if __GLASGOW_HASKELL__ < 609
342 rethrow dflags io = Exception.catch io $ \e -> do -- NB. not catchDyn
344 -- If -fbreak-on-error, we break unconditionally,
345 -- but with care of not breaking twice
346 _ | dopt Opt_BreakOnError dflags &&
347 not(dopt Opt_BreakOnException dflags)
348 -> poke exceptionFlag 1
350 -- If it is an "Interrupted" exception, we allow
351 -- a possible break by way of -fbreak-on-exception
352 DynException d | Just Interrupted <- fromDynamic d
355 -- In any other case, we don't want to break
356 _ -> poke exceptionFlag 0
360 rethrow dflags io = Exception.catch io $ \se@(SomeException e) -> do
361 -- If -fbreak-on-error, we break unconditionally,
362 -- but with care of not breaking twice
363 if dopt Opt_BreakOnError dflags &&
364 not (dopt Opt_BreakOnException dflags)
365 then poke exceptionFlag 1
367 -- If it is an "Interrupted" exception, we allow
368 -- a possible break by way of -fbreak-on-exception
369 Just Interrupted -> return ()
370 -- In any other case, we don't want to break
371 _ -> poke exceptionFlag 0
376 withInterruptsSentTo :: ThreadId -> IO r -> IO r
377 withInterruptsSentTo thread get_result = do
378 bracket (modifyMVar_ interruptTargetThread (return . (thread:)))
379 (\_ -> modifyMVar_ interruptTargetThread (\tl -> return $! tail tl))
382 -- This function sets up the interpreter for catching breakpoints, and
383 -- resets everything when the computation has stopped running. This
384 -- is a not-very-good way to ensure that only the interactive
385 -- evaluation should generate breakpoints.
386 withBreakAction :: Bool -> DynFlags -> MVar () -> MVar Status -> IO a -> IO a
387 withBreakAction step dflags breakMVar statusMVar io
388 = bracket setBreakAction resetBreakAction (\_ -> io)
391 stablePtr <- newStablePtr onBreak
392 poke breakPointIOAction stablePtr
393 when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
394 when step $ setStepFlag
396 -- Breaking on exceptions is not enabled by default, since it
397 -- might be a bit surprising. The exception flag is turned off
398 -- as soon as it is hit, or in resetBreakAction below.
400 onBreak is_exception info apStack = do
402 putMVar statusMVar (Break is_exception apStack info tid)
405 resetBreakAction stablePtr = do
406 poke breakPointIOAction noBreakStablePtr
409 freeStablePtr stablePtr
411 noBreakStablePtr :: StablePtr (Bool -> BreakInfo -> HValue -> IO ())
412 noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
414 noBreakAction :: Bool -> BreakInfo -> HValue -> IO ()
415 noBreakAction False _ _ = putStrLn "*** Ignoring breakpoint"
416 noBreakAction True _ _ = return () -- exception: just continue
418 resume :: Session -> SingleStep -> IO RunResult
419 resume (Session ref) step
421 hsc_env <- readIORef ref
422 let ic = hsc_IC hsc_env
423 resume = ic_resume ic
426 [] -> ghcError (ProgramError "not stopped at a breakpoint")
428 -- unbind the temporary locals by restoring the TypeEnv from
429 -- before the breakpoint, and drop this Resume from the
430 -- InteractiveContext.
431 let (resume_tmp_ids, resume_tyvars) = resumeBindings r
432 ic' = ic { ic_tmp_ids = resume_tmp_ids,
433 ic_tyvars = resume_tyvars,
435 writeIORef ref hsc_env{ hsc_IC = ic' }
437 -- remove any bindings created since the breakpoint from the
438 -- linker's environment
439 let new_names = map idName (filter (`notElem` resume_tmp_ids)
441 Linker.deleteFromLinkEnv new_names
443 when (isStep step) $ setStepFlag
445 Resume expr tid breakMVar statusMVar bindings
446 final_ids apStack info _ hist _ -> do
447 withBreakAction (isStep step) (hsc_dflags hsc_env)
448 breakMVar statusMVar $ do
449 status <- withInterruptsSentTo tid $ do
451 -- this awakens the stopped thread...
453 -- and wait for the result
456 Nothing -> fromListBL 50 hist
457 Just i -> mkHistory hsc_env apStack i `consBL`
461 traceRunStatus expr ref bindings final_ids
462 breakMVar statusMVar status hist'
464 handleRunStatus expr ref bindings final_ids
465 breakMVar statusMVar status hist'
467 back :: Session -> IO ([Name], Int, SrcSpan)
470 forward :: Session -> IO ([Name], Int, SrcSpan)
471 forward = moveHist (subtract 1)
473 moveHist :: (Int -> Int) -> Session -> IO ([Name], Int, SrcSpan)
474 moveHist fn (Session ref) = do
475 hsc_env <- readIORef ref
476 case ic_resume (hsc_IC hsc_env) of
477 [] -> ghcError (ProgramError "not stopped at a breakpoint")
479 let ix = resumeHistoryIx r
480 history = resumeHistory r
483 when (new_ix > length history) $
484 ghcError (ProgramError "no more logged breakpoints")
486 ghcError (ProgramError "already at the beginning of the history")
489 update_ic apStack mb_info = do
490 (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
492 let ic = hsc_IC hsc_env1
493 r' = r { resumeHistoryIx = new_ix }
494 ic' = ic { ic_resume = r':rs }
496 writeIORef ref hsc_env1{ hsc_IC = ic' }
498 return (names, new_ix, span)
500 -- careful: we want apStack to be the AP_STACK itself, not a thunk
501 -- around it, hence the cases are carefully constructed below to
502 -- make this the case. ToDo: this is v. fragile, do something better.
505 Resume { resumeApStack = apStack,
506 resumeBreakInfo = mb_info } ->
507 update_ic apStack mb_info
508 else case history !! (new_ix - 1) of
509 History apStack info _ ->
510 update_ic apStack (Just info)
512 -- -----------------------------------------------------------------------------
513 -- After stopping at a breakpoint, add free variables to the environment
514 result_fs :: FastString
515 result_fs = fsLit "_result"
517 bindLocalsAtBreakpoint
521 -> IO (HscEnv, [Name], SrcSpan)
523 -- Nothing case: we stopped when an exception was raised, not at a
524 -- breakpoint. We have no location information or local variables to
525 -- bind, all we can do is bind a local variable to the exception
527 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
528 let exn_fs = fsLit "_exception"
529 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
531 e_name = mkInternalName (getUnique e_fs) (mkTyVarOccFS e_fs) span
532 e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
533 exn_id = Id.mkGlobalId VanillaGlobal exn_name (mkTyVarTy e_tyvar)
535 new_tyvars = unitVarSet e_tyvar
537 ictxt0 = hsc_IC hsc_env
538 ictxt1 = extendInteractiveContext ictxt0 [exn_id] new_tyvars
540 span = mkGeneralSrcSpan (fsLit "<exception thrown>")
542 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
543 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
545 -- Just case: we stopped at a breakpoint, we have information about the location
546 -- of the breakpoint and the free variables of the expression.
547 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
550 mod_name = moduleName (breakInfo_module info)
551 hmi = expectJust "bindLocalsAtBreakpoint" $
552 lookupUFM (hsc_HPT hsc_env) mod_name
553 breaks = getModBreaks hmi
554 index = breakInfo_number info
555 vars = breakInfo_vars info
556 result_ty = breakInfo_resty info
557 occs = modBreaks_vars breaks ! index
558 span = modBreaks_locs breaks ! index
560 -- filter out any unboxed ids; we can't bind these at the prompt
561 let pointers = filter (\(id,_) -> isPointer id) vars
562 isPointer id | PtrRep <- idPrimRep id = True
565 let (ids, offsets) = unzip pointers
567 -- It might be that getIdValFromApStack fails, because the AP_STACK
568 -- has been accidentally evaluated, or something else has gone wrong.
569 -- So that we don't fall over in a heap when this happens, just don't
570 -- bind any free variables instead, and we emit a warning.
571 mb_hValues <- mapM (getIdValFromApStack apStack) offsets
572 let filtered_ids = [ id | (id, Just _hv) <- zip ids mb_hValues ]
573 when (any isNothing mb_hValues) $
574 debugTraceMsg (hsc_dflags hsc_env) 1 $
575 text "Warning: _result has been evaluated, some bindings have been lost"
577 new_ids <- zipWithM mkNewId occs filtered_ids
578 let names = map idName new_ids
580 -- make an Id for _result. We use the Unique of the FastString "_result";
581 -- we don't care about uniqueness here, because there will only be one
582 -- _result in scope at any time.
583 let result_name = mkInternalName (getUnique result_fs)
584 (mkVarOccFS result_fs) span
585 result_id = Id.mkGlobalId VanillaGlobal result_name result_ty
588 -- for each Id we're about to bind in the local envt:
589 -- - skolemise the type variables in its type, so they can't
590 -- be randomly unified with other types. These type variables
591 -- can only be resolved by type reconstruction in RtClosureInspect
592 -- - tidy the type variables
593 -- - globalise the Id (Ids are supposed to be Global, apparently).
595 let all_ids | isPointer result_id = result_id : new_ids
596 | otherwise = new_ids
597 (id_tys, tyvarss) = mapAndUnzip (skolemiseTy.idType) all_ids
598 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
599 new_tyvars = unionVarSets tyvarss
600 let final_ids = zipWith setIdType all_ids tidy_tys
601 ictxt0 = hsc_IC hsc_env
602 ictxt1 = extendInteractiveContext ictxt0 final_ids new_tyvars
603 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
604 Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
605 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
606 return (hsc_env1, result_name:names, span)
608 mkNewId :: OccName -> Id -> IO Id
610 us <- mkSplitUniqSupply 'I'
611 -- we need a fresh Unique for each Id we bind, because the linker
612 -- state is single-threaded and otherwise we'd spam old bindings
613 -- whenever we stop at a breakpoint. The InteractveContext is properly
614 -- saved/restored, but not the linker state. See #1743, test break026.
616 uniq = uniqFromSupply us
617 loc = nameSrcSpan (idName id)
618 name = mkInternalName uniq occ loc
620 new_id = Id.mkGlobalId VanillaGlobal name ty (idInfo id)
623 rttiEnvironment :: HscEnv -> IO HscEnv
624 rttiEnvironment hsc_env@HscEnv{hsc_IC=ic} = do
625 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
626 incompletelyTypedIds =
628 , not $ null [v | v <- varSetElems$ tyVarsOfType (idType id)
630 , (occNameFS.nameOccName.idName) id /= result_fs]
631 tys <- reconstructType hsc_env 10 `mapM` incompletelyTypedIds
632 -- map termType `fmap` (obtainTerm hsc_env False `mapM` incompletelyTypedIds)
634 improvs <- sequence [improveRTTIType hsc_env ty ty'
635 | (ty, Just ty') <- zip (map idType incompletelyTypedIds) tys]
636 let ic' = foldr (\mb_subst ic' ->
637 maybe (WARN(True, text ("RTTI failed to calculate the "
638 ++ "improvement for a type")) ic')
639 (substInteractiveContext ic' . skolemiseSubst)
643 return hsc_env{hsc_IC=ic'}
645 skolemiseSubst :: TvSubst -> TvSubst
646 skolemiseSubst subst = subst `setTvSubstEnv`
647 mapVarEnv (fst.skolemiseTy) (getTvSubstEnv subst)
649 skolemiseTy :: Type -> (Type, TyVarSet)
650 skolemiseTy ty = (substTy subst ty, mkVarSet new_tyvars)
651 where env = mkVarEnv (zip tyvars new_tyvar_tys)
652 subst = mkTvSubst emptyInScopeSet env
653 tyvars = varSetElems (tyVarsOfType ty)
654 new_tyvars = map skolemiseTyVar tyvars
655 new_tyvar_tys = map mkTyVarTy new_tyvars
657 skolemiseTyVar :: TyVar -> TyVar
658 skolemiseTyVar tyvar = mkTcTyVar (tyVarName tyvar) (tyVarKind tyvar)
659 (SkolemTv RuntimeUnkSkol)
661 getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
662 getIdValFromApStack apStack (I# stackDepth) = do
663 case getApStackVal# apStack (stackDepth +# 1#) of
664 -- The +1 is magic! I don't know where it comes
665 -- from, but this makes things line up. --SDM
668 0# -> return Nothing -- AP_STACK not found
669 _ -> return (Just (unsafeCoerce# result))
671 pushResume :: HscEnv -> Resume -> HscEnv
672 pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
674 ictxt0 = hsc_IC hsc_env
675 ictxt1 = ictxt0 { ic_resume = resume : ic_resume ictxt0 }
677 -- -----------------------------------------------------------------------------
678 -- Abandoning a resume context
680 abandon :: Session -> IO Bool
681 abandon (Session ref) = do
682 hsc_env <- readIORef ref
683 let ic = hsc_IC hsc_env
684 resume = ic_resume ic
688 writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = rs } }
692 abandonAll :: Session -> IO Bool
693 abandonAll (Session ref) = do
694 hsc_env <- readIORef ref
695 let ic = hsc_IC hsc_env
696 resume = ic_resume ic
700 writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = [] } }
704 -- when abandoning a computation we have to
705 -- (a) kill the thread with an async exception, so that the
706 -- computation itself is stopped, and
707 -- (b) fill in the MVar. This step is necessary because any
708 -- thunks that were under evaluation will now be updated
709 -- with the partial computation, which still ends in takeMVar,
710 -- so any attempt to evaluate one of these thunks will block
711 -- unless we fill in the MVar.
712 -- See test break010.
713 abandon_ :: Resume -> IO ()
715 killThread (resumeThreadId r)
716 putMVar (resumeBreakMVar r) ()
718 -- -----------------------------------------------------------------------------
719 -- Bounded list, optimised for repeated cons
721 data BoundedList a = BL
722 {-# UNPACK #-} !Int -- length
723 {-# UNPACK #-} !Int -- bound
725 [a] -- right, list is (left ++ reverse right)
727 nilBL :: Int -> BoundedList a
728 nilBL bound = BL 0 bound [] []
730 consBL :: a -> BoundedList a -> BoundedList a
731 consBL a (BL len bound left right)
732 | len < bound = BL (len+1) bound (a:left) right
733 | null right = BL len bound [a] $! tail (reverse left)
734 | otherwise = BL len bound (a:left) $! tail right
736 toListBL :: BoundedList a -> [a]
737 toListBL (BL _ _ left right) = left ++ reverse right
739 fromListBL :: Int -> [a] -> BoundedList a
740 fromListBL bound l = BL (length l) bound l []
742 -- lenBL (BL len _ _ _) = len
744 -- -----------------------------------------------------------------------------
745 -- | Set the interactive evaluation context.
747 -- Setting the context doesn't throw away any bindings; the bindings
748 -- we've built up in the InteractiveContext simply move to the new
749 -- module. They always shadow anything in scope in the current context.
750 setContext :: Session
751 -> [Module] -- entire top level scope of these modules
752 -> [Module] -- exports only of these modules
754 setContext (Session ref) toplev_mods export_mods = do
755 hsc_env <- readIORef ref
756 let old_ic = hsc_IC hsc_env
757 hpt = hsc_HPT hsc_env
759 export_env <- mkExportEnv hsc_env export_mods
760 toplev_envs <- mapM (mkTopLevEnv hpt) toplev_mods
761 let all_env = foldr plusGlobalRdrEnv export_env toplev_envs
762 writeIORef ref hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
763 ic_exports = export_mods,
764 ic_rn_gbl_env = all_env }}
766 -- Make a GlobalRdrEnv based on the exports of the modules only.
767 mkExportEnv :: HscEnv -> [Module] -> IO GlobalRdrEnv
768 mkExportEnv hsc_env mods = do
769 stuff <- mapM (getModuleExports hsc_env) mods
771 (_msgs, mb_name_sets) = unzip stuff
772 gres = [ nameSetToGlobalRdrEnv (availsToNameSet avails) (moduleName mod)
773 | (Just avails, mod) <- zip mb_name_sets mods ]
775 return $! foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres
777 nameSetToGlobalRdrEnv :: NameSet -> ModuleName -> GlobalRdrEnv
778 nameSetToGlobalRdrEnv names mod =
779 mkGlobalRdrEnv [ GRE { gre_name = name, gre_par = NoParent, gre_prov = vanillaProv mod }
780 | name <- nameSetToList names ]
782 vanillaProv :: ModuleName -> Provenance
783 -- We're building a GlobalRdrEnv as if the user imported
784 -- all the specified modules into the global interactive module
785 vanillaProv mod_name = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
787 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
789 is_dloc = srcLocSpan interactiveSrcLoc }
791 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
793 = case lookupUFM hpt (moduleName modl) of
794 Nothing -> ghcError (ProgramError ("mkTopLevEnv: not a home module " ++
795 showSDoc (ppr modl)))
797 case mi_globals (hm_iface details) of
799 ghcError (ProgramError ("mkTopLevEnv: not interpreted "
800 ++ showSDoc (ppr modl)))
801 Just env -> return env
803 -- | Get the interactive evaluation context, consisting of a pair of the
804 -- set of modules from which we take the full top-level scope, and the set
805 -- of modules from which we take just the exports respectively.
806 getContext :: Session -> IO ([Module],[Module])
807 getContext s = withSession s (\HscEnv{ hsc_IC=ic } ->
808 return (ic_toplev_scope ic, ic_exports ic))
810 -- | Returns @True@ if the specified module is interpreted, and hence has
811 -- its full top-level scope available.
812 moduleIsInterpreted :: Session -> Module -> IO Bool
813 moduleIsInterpreted s modl = withSession s $ \h ->
814 if modulePackageId modl /= thisPackage (hsc_dflags h)
816 else case lookupUFM (hsc_HPT h) (moduleName modl) of
817 Just details -> return (isJust (mi_globals (hm_iface details)))
818 _not_a_home_module -> return False
820 -- | Looks up an identifier in the current interactive context (for :info)
821 -- Filter the instances by the ones whose tycons (or clases resp)
822 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
823 -- The exact choice of which ones to show, and which to hide, is a judgement call.
825 getInfo :: Session -> Name -> IO (Maybe (TyThing,Fixity,[Instance]))
827 = withSession s $ \hsc_env ->
828 do mb_stuff <- tcRnGetInfo hsc_env name
830 Nothing -> return Nothing
831 Just (thing, fixity, ispecs) -> do
832 let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
833 return (Just (thing, fixity, filter (plausible rdr_env) ispecs))
835 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
836 = all ok $ nameSetToList $ tyClsNamesOfType $ idType $ instanceDFunId ispec
837 where -- A name is ok if it's in the rdr_env,
838 -- whether qualified or not
839 ok n | n == name = True -- The one we looked for in the first place!
840 | isBuiltInSyntax n = True
841 | isExternalName n = any ((== n) . gre_name)
842 (lookupGRE_Name rdr_env n)
845 -- | Returns all names in scope in the current interactive context
846 getNamesInScope :: Session -> IO [Name]
847 getNamesInScope s = withSession s $ \hsc_env -> do
848 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
850 getRdrNamesInScope :: Session -> IO [RdrName]
851 getRdrNamesInScope s = withSession s $ \hsc_env -> do
854 gbl_rdrenv = ic_rn_gbl_env ic
856 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
857 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
859 return (gbl_names ++ lcl_names)
862 -- ToDo: move to RdrName
863 greToRdrNames :: GlobalRdrElt -> [RdrName]
864 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
867 Imported specs -> concat (map do_spec (map is_decl specs))
869 occ = nameOccName name
872 | is_qual decl_spec = [qual]
873 | otherwise = [unqual,qual]
874 where qual = Qual (is_as decl_spec) occ
876 -- | Parses a string as an identifier, and returns the list of 'Name's that
877 -- the identifier can refer to in the current interactive context.
878 parseName :: Session -> String -> IO [Name]
879 parseName s str = withSession s $ \hsc_env -> do
880 maybe_rdr_name <- hscParseIdentifier (hsc_dflags hsc_env) str
881 case maybe_rdr_name of
883 Just (L _ rdr_name) -> do
884 mb_names <- tcRnLookupRdrName hsc_env rdr_name
888 -- ToDo: should return error messages
890 -- | Returns the 'TyThing' for a 'Name'. The 'Name' may refer to any
891 -- entity known to GHC, including 'Name's defined using 'runStmt'.
892 lookupName :: Session -> Name -> IO (Maybe TyThing)
893 lookupName s name = withSession s $ \hsc_env -> tcRnLookupName hsc_env name
895 -- -----------------------------------------------------------------------------
896 -- Getting the type of an expression
898 -- | Get the type of an expression
899 exprType :: Session -> String -> IO (Maybe Type)
900 exprType s expr = withSession s $ \hsc_env -> do
901 maybe_stuff <- hscTcExpr hsc_env expr
903 Nothing -> return Nothing
904 Just ty -> return (Just tidy_ty)
906 tidy_ty = tidyType emptyTidyEnv ty
908 -- -----------------------------------------------------------------------------
909 -- Getting the kind of a type
911 -- | Get the kind of a type
912 typeKind :: Session -> String -> IO (Maybe Kind)
913 typeKind s str = withSession s $ \hsc_env -> do
914 maybe_stuff <- hscKcType hsc_env str
916 Nothing -> return Nothing
917 Just kind -> return (Just kind)
919 -----------------------------------------------------------------------------
920 -- cmCompileExpr: compile an expression and deliver an HValue
922 compileExpr :: Session -> String -> IO (Maybe HValue)
923 compileExpr s expr = withSession s $ \hsc_env -> do
924 maybe_stuff <- hscStmt hsc_env ("let __cmCompileExpr = "++expr)
926 Nothing -> return Nothing
927 Just (ids, hval) -> do
929 hvals <- (unsafeCoerce# hval) :: IO [HValue]
932 ([_],[hv]) -> return (Just hv)
933 _ -> panic "compileExpr"
935 -- -----------------------------------------------------------------------------
936 -- Compile an expression into a dynamic
938 dynCompileExpr :: Session -> String -> IO (Maybe Dynamic)
939 dynCompileExpr ses expr = do
940 (full,exports) <- getContext ses
941 setContext ses full $
943 (stringToPackageId "base") (mkModuleName "Data.Dynamic")
945 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
946 res <- withSession ses (flip hscStmt stmt)
947 setContext ses full exports
949 Nothing -> return Nothing
950 Just (ids, hvals) -> do
951 vals <- (unsafeCoerce# hvals :: IO [Dynamic])
953 (_:[], v:[]) -> return (Just v)
954 _ -> panic "dynCompileExpr"
956 -----------------------------------------------------------------------------
957 -- show a module and it's source/object filenames
959 showModule :: Session -> ModSummary -> IO String
960 showModule s mod_summary = withSession s $ \hsc_env ->
961 isModuleInterpreted s mod_summary >>= \interpreted ->
962 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
964 isModuleInterpreted :: Session -> ModSummary -> IO Bool
965 isModuleInterpreted s mod_summary = withSession s $ \hsc_env ->
966 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
967 Nothing -> panic "missing linkable"
968 Just mod_info -> return (not obj_linkable)
970 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
972 ----------------------------------------------------------------------------
975 obtainTerm1 :: HscEnv -> Bool -> Maybe Type -> a -> IO Term
976 obtainTerm1 hsc_env force mb_ty x =
977 cvObtainTerm hsc_env maxBound force mb_ty (unsafeCoerce# x)
979 obtainTermB :: HscEnv -> Int -> Bool -> Id -> IO Term
980 obtainTermB hsc_env bound force id = do
981 hv <- Linker.getHValue hsc_env (varName id)
982 cvObtainTerm hsc_env bound force (Just$ idType id) hv
984 obtainTerm :: HscEnv -> Bool -> Id -> IO Term
985 obtainTerm hsc_env force id = do
986 hv <- Linker.getHValue hsc_env (varName id)
987 cvObtainTerm hsc_env maxBound force (Just$ idType id) hv
989 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
990 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
991 reconstructType hsc_env bound id = do
992 hv <- Linker.getHValue hsc_env (varName id)
993 cvReconstructType hsc_env bound (Just$ idType id) hv