1 -- -----------------------------------------------------------------------------
3 -- (c) The University of Glasgow, 2005-2007
5 -- Running statements interactively
7 -- -----------------------------------------------------------------------------
9 module InteractiveEval (
11 RunResult(..), Status(..), Resume(..), History(..),
12 runStmt, parseImportDecl, SingleStep(..),
20 setContext, getContext,
31 compileExpr, dynCompileExpr,
32 Term(..), obtainTermFromId, obtainTermFromVal, reconstructType
38 #include "HsVersions.h"
42 import HsSyn (ImportDecl)
45 import RnNames (gresFromAvails)
48 import TcType hiding( typeKind )
51 import Name hiding ( varName )
54 import PrelNames (pRELUDE)
70 import RtClosureInspect
76 import System.Directory
78 import Data.List (find, partition)
80 import Foreign hiding (unsafePerformIO)
85 import Control.Concurrent
86 import Data.List (sortBy)
87 -- import Foreign.StablePtr
89 import System.IO.Unsafe
91 -- -----------------------------------------------------------------------------
92 -- running a statement interactively
95 = RunOk [Name] -- ^ names bound by this evaluation
96 | RunFailed -- ^ statement failed compilation
97 | RunException SomeException -- ^ statement raised an exception
98 | RunBreak ThreadId [Name] (Maybe BreakInfo)
101 = Break Bool HValue BreakInfo ThreadId
102 -- ^ the computation hit a breakpoint (Bool <=> was an exception)
103 | Complete (Either SomeException [HValue])
104 -- ^ the computation completed with either an exception or a value
108 resumeStmt :: String, -- the original statement
109 resumeThreadId :: ThreadId, -- thread running the computation
110 resumeBreakMVar :: MVar (),
111 resumeStatMVar :: MVar Status,
112 resumeBindings :: [Id],
113 resumeFinalIds :: [Id], -- [Id] to bind on completion
114 resumeApStack :: HValue, -- The object from which we can get
115 -- value of the free variables.
116 resumeBreakInfo :: Maybe BreakInfo,
117 -- the breakpoint we stopped at
118 -- (Nothing <=> exception)
119 resumeSpan :: SrcSpan, -- just a cache, otherwise it's a pain
120 -- to fetch the ModDetails & ModBreaks
122 resumeHistory :: [History],
123 resumeHistoryIx :: Int -- 0 <==> at the top of the history
126 getResumeContext :: GhcMonad m => m [Resume]
127 getResumeContext = withSession (return . ic_resume . hsc_IC)
134 isStep :: SingleStep -> Bool
135 isStep RunToCompletion = False
140 historyApStack :: HValue,
141 historyBreakInfo :: BreakInfo,
142 historyEnclosingDecl :: Id
143 -- ^^ A cache of the enclosing top level declaration, for convenience
146 mkHistory :: HscEnv -> HValue -> BreakInfo -> History
147 mkHistory hsc_env hval bi = let
148 h = History hval bi decl
149 decl = findEnclosingDecl hsc_env (getHistoryModule h)
150 (getHistorySpan hsc_env h)
153 getHistoryModule :: History -> Module
154 getHistoryModule = breakInfo_module . historyBreakInfo
156 getHistorySpan :: HscEnv -> History -> SrcSpan
157 getHistorySpan hsc_env hist =
158 let inf = historyBreakInfo hist
159 num = breakInfo_number inf
160 in case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
161 Just hmi -> modBreaks_locs (getModBreaks hmi) ! num
162 _ -> panic "getHistorySpan"
164 getModBreaks :: HomeModInfo -> ModBreaks
166 | Just linkable <- hm_linkable hmi,
167 [BCOs _ modBreaks] <- linkableUnlinked linkable
170 = emptyModBreaks -- probably object code
172 {- | Finds the enclosing top level function name -}
173 -- ToDo: a better way to do this would be to keep hold of the decl_path computed
174 -- by the coverage pass, which gives the list of lexically-enclosing bindings
176 findEnclosingDecl :: HscEnv -> Module -> SrcSpan -> Id
177 findEnclosingDecl hsc_env mod span =
178 case lookupUFM (hsc_HPT hsc_env) (moduleName mod) of
179 Nothing -> panic "findEnclosingDecl"
181 globals = typeEnvIds (md_types (hm_details hmi))
183 find (\id -> let n = idName id in
184 nameSrcSpan n < span && isExternalName n)
185 (reverse$ sortBy (compare `on` (nameSrcSpan.idName))
189 -- | Run a statement in the current interactive context. Statement
190 -- may bind multple values.
191 runStmt :: GhcMonad m => String -> SingleStep -> m RunResult
194 hsc_env <- getSession
196 breakMVar <- liftIO $ newEmptyMVar -- wait on this when we hit a breakpoint
197 statusMVar <- liftIO $ newEmptyMVar -- wait on this when a computation is running
199 -- Turn off -fwarn-unused-bindings when running a statement, to hide
200 -- warnings about the implicit bindings we introduce.
201 let dflags' = dopt_unset (hsc_dflags hsc_env) Opt_WarnUnusedBinds
202 hsc_env' = hsc_env{ hsc_dflags = dflags' }
204 r <- liftIO $ hscStmt hsc_env' expr
207 Nothing -> return RunFailed -- empty statement / comment
209 Just (ids, hval) -> do
212 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
213 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
214 liftIO $ sandboxIO dflags' statusMVar thing_to_run
216 let ic = hsc_IC hsc_env
217 bindings = ic_tmp_ids ic
221 traceRunStatus expr bindings ids
222 breakMVar statusMVar status emptyHistory
224 handleRunStatus expr bindings ids
225 breakMVar statusMVar status emptyHistory
227 withVirtualCWD :: GhcMonad m => m a -> m a
228 withVirtualCWD m = do
229 hsc_env <- getSession
230 let ic = hsc_IC hsc_env
233 dir <- liftIO $ getCurrentDirectory
235 Just dir -> liftIO $ setCurrentDirectory dir
239 reset_cwd orig_dir = do
240 virt_dir <- liftIO $ getCurrentDirectory
241 hsc_env <- getSession
242 let old_IC = hsc_IC hsc_env
243 setSession hsc_env{ hsc_IC = old_IC{ ic_cwd = Just virt_dir } }
244 liftIO $ setCurrentDirectory orig_dir
246 gbracket set_cwd reset_cwd $ \_ -> m
248 parseImportDecl :: GhcMonad m => String -> m (ImportDecl RdrName)
249 parseImportDecl expr = withSession $ \hsc_env -> liftIO $ hscImport hsc_env expr
251 emptyHistory :: BoundedList History
252 emptyHistory = nilBL 50 -- keep a log of length 50
254 handleRunStatus :: GhcMonad m =>
255 String-> [Id] -> [Id]
256 -> MVar () -> MVar Status -> Status -> BoundedList History
258 handleRunStatus expr bindings final_ids breakMVar statusMVar status
261 -- did we hit a breakpoint or did we complete?
262 (Break is_exception apStack info tid) -> do
263 hsc_env <- getSession
264 let mb_info | is_exception = Nothing
265 | otherwise = Just info
266 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env apStack
269 resume = Resume { resumeStmt = expr, resumeThreadId = tid
270 , resumeBreakMVar = breakMVar, resumeStatMVar = statusMVar
271 , resumeBindings = bindings, resumeFinalIds = final_ids
272 , resumeApStack = apStack, resumeBreakInfo = mb_info
273 , resumeSpan = span, resumeHistory = toListBL history
274 , resumeHistoryIx = 0 }
275 hsc_env2 = pushResume hsc_env1 resume
277 modifySession (\_ -> hsc_env2)
278 return (RunBreak tid names mb_info)
279 (Complete either_hvals) ->
281 Left e -> return (RunException e)
283 hsc_env <- getSession
284 let final_ic = extendInteractiveContext (hsc_IC hsc_env) final_ids
285 final_names = map idName final_ids
286 liftIO $ Linker.extendLinkEnv (zip final_names hvals)
287 hsc_env' <- liftIO $ rttiEnvironment hsc_env{hsc_IC=final_ic}
288 modifySession (\_ -> hsc_env')
289 return (RunOk final_names)
291 traceRunStatus :: GhcMonad m =>
292 String -> [Id] -> [Id]
293 -> MVar () -> MVar Status -> Status -> BoundedList History
295 traceRunStatus expr bindings final_ids
296 breakMVar statusMVar status history = do
297 hsc_env <- getSession
299 -- when tracing, if we hit a breakpoint that is not explicitly
300 -- enabled, then we just log the event in the history and continue.
301 (Break is_exception apStack info tid) | not is_exception -> do
302 b <- liftIO $ isBreakEnabled hsc_env info
306 let history' = mkHistory hsc_env apStack info `consBL` history
307 -- probably better make history strict here, otherwise
308 -- our BoundedList will be pointless.
309 _ <- liftIO $ evaluate history'
311 withBreakAction True (hsc_dflags hsc_env)
312 breakMVar statusMVar $ do
313 liftIO $ withInterruptsSentTo tid $ do
314 putMVar breakMVar () -- awaken the stopped thread
315 takeMVar statusMVar -- and wait for the result
316 traceRunStatus expr bindings final_ids
317 breakMVar statusMVar status history'
321 handle_normally = handleRunStatus expr bindings final_ids
322 breakMVar statusMVar status history
325 isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
326 isBreakEnabled hsc_env inf =
327 case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
329 w <- getBreak (modBreaks_flags (getModBreaks hmi))
330 (breakInfo_number inf)
331 case w of Just n -> return (n /= 0); _other -> return False
336 foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
337 foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
340 setStepFlag = poke stepFlag 1
341 resetStepFlag :: IO ()
342 resetStepFlag = poke stepFlag 0
344 -- this points to the IO action that is executed when a breakpoint is hit
345 foreign import ccall "&rts_breakpoint_io_action"
346 breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
348 -- When running a computation, we redirect ^C exceptions to the running
349 -- thread. ToDo: we might want a way to continue even if the target
350 -- thread doesn't die when it receives the exception... "this thread
351 -- is not responding".
353 -- Careful here: there may be ^C exceptions flying around, so we start the new
354 -- thread blocked (forkIO inherits mask from the parent, #1048), and unblock
355 -- only while we execute the user's code. We can't afford to lose the final
356 -- putMVar, otherwise deadlock ensues. (#1583, #1922, #1946)
357 sandboxIO :: DynFlags -> MVar Status -> IO [HValue] -> IO Status
358 sandboxIO dflags statusMVar thing =
359 mask $ \restore -> -- fork starts blocked
360 let runIt = liftM Complete $ try (restore $ rethrow dflags thing)
361 in if dopt Opt_GhciSandbox dflags
362 then do tid <- forkIO $ do res <- runIt
363 putMVar statusMVar res -- empty: can't block
364 withInterruptsSentTo tid $ takeMVar statusMVar
365 else -- GLUT on OS X needs to run on the main thread. If you
366 -- try to use it from another thread then you just get a
367 -- white rectangle rendered. For this, or anything else
368 -- with such restrictions, you can turn the GHCi sandbox off
369 -- and things will be run in the main thread.
372 -- We want to turn ^C into a break when -fbreak-on-exception is on,
373 -- but it's an async exception and we only break for sync exceptions.
374 -- Idea: if we catch and re-throw it, then the re-throw will trigger
375 -- a break. Great - but we don't want to re-throw all exceptions, because
376 -- then we'll get a double break for ordinary sync exceptions (you'd have
377 -- to :continue twice, which looks strange). So if the exception is
378 -- not "Interrupted", we unset the exception flag before throwing.
380 rethrow :: DynFlags -> IO a -> IO a
381 rethrow dflags io = Exception.catch io $ \se -> do
382 -- If -fbreak-on-error, we break unconditionally,
383 -- but with care of not breaking twice
384 if dopt Opt_BreakOnError dflags &&
385 not (dopt Opt_BreakOnException dflags)
386 then poke exceptionFlag 1
387 else case fromException se of
388 -- If it is a "UserInterrupt" exception, we allow
389 -- a possible break by way of -fbreak-on-exception
390 Just UserInterrupt -> return ()
391 -- In any other case, we don't want to break
392 _ -> poke exceptionFlag 0
396 withInterruptsSentTo :: ThreadId -> IO r -> IO r
397 withInterruptsSentTo thread get_result = do
398 bracket (modifyMVar_ interruptTargetThread (return . (thread:)))
399 (\_ -> modifyMVar_ interruptTargetThread (\tl -> return $! tail tl))
402 -- This function sets up the interpreter for catching breakpoints, and
403 -- resets everything when the computation has stopped running. This
404 -- is a not-very-good way to ensure that only the interactive
405 -- evaluation should generate breakpoints.
406 withBreakAction :: (ExceptionMonad m, MonadIO m) =>
407 Bool -> DynFlags -> MVar () -> MVar Status -> m a -> m a
408 withBreakAction step dflags breakMVar statusMVar act
409 = gbracket (liftIO setBreakAction) (liftIO . resetBreakAction) (\_ -> act)
412 stablePtr <- newStablePtr onBreak
413 poke breakPointIOAction stablePtr
414 when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
415 when step $ setStepFlag
417 -- Breaking on exceptions is not enabled by default, since it
418 -- might be a bit surprising. The exception flag is turned off
419 -- as soon as it is hit, or in resetBreakAction below.
421 onBreak is_exception info apStack = do
423 putMVar statusMVar (Break is_exception apStack info tid)
426 resetBreakAction stablePtr = do
427 poke breakPointIOAction noBreakStablePtr
430 freeStablePtr stablePtr
432 noBreakStablePtr :: StablePtr (Bool -> BreakInfo -> HValue -> IO ())
433 noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
435 noBreakAction :: Bool -> BreakInfo -> HValue -> IO ()
436 noBreakAction False _ _ = putStrLn "*** Ignoring breakpoint"
437 noBreakAction True _ _ = return () -- exception: just continue
439 resume :: GhcMonad m => (SrcSpan->Bool) -> SingleStep -> m RunResult
440 resume canLogSpan step
442 hsc_env <- getSession
443 let ic = hsc_IC hsc_env
444 resume = ic_resume ic
447 [] -> ghcError (ProgramError "not stopped at a breakpoint")
449 -- unbind the temporary locals by restoring the TypeEnv from
450 -- before the breakpoint, and drop this Resume from the
451 -- InteractiveContext.
452 let resume_tmp_ids = resumeBindings r
453 ic' = ic { ic_tmp_ids = resume_tmp_ids,
455 modifySession (\_ -> hsc_env{ hsc_IC = ic' })
457 -- remove any bindings created since the breakpoint from the
458 -- linker's environment
459 let new_names = map idName (filter (`notElem` resume_tmp_ids)
461 liftIO $ Linker.deleteFromLinkEnv new_names
463 when (isStep step) $ liftIO setStepFlag
465 Resume { resumeStmt = expr, resumeThreadId = tid
466 , resumeBreakMVar = breakMVar, resumeStatMVar = statusMVar
467 , resumeBindings = bindings, resumeFinalIds = final_ids
468 , resumeApStack = apStack, resumeBreakInfo = info, resumeSpan = span
469 , resumeHistory = hist } -> do
471 withBreakAction (isStep step) (hsc_dflags hsc_env)
472 breakMVar statusMVar $ do
473 status <- liftIO $ withInterruptsSentTo tid $ do
475 -- this awakens the stopped thread...
477 -- and wait for the result
478 let prevHistoryLst = fromListBL 50 hist
480 Nothing -> prevHistoryLst
482 | not $canLogSpan span -> prevHistoryLst
483 | otherwise -> mkHistory hsc_env apStack i `consBL`
487 traceRunStatus expr bindings final_ids
488 breakMVar statusMVar status hist'
490 handleRunStatus expr bindings final_ids
491 breakMVar statusMVar status hist'
493 back :: GhcMonad m => m ([Name], Int, SrcSpan)
496 forward :: GhcMonad m => m ([Name], Int, SrcSpan)
497 forward = moveHist (subtract 1)
499 moveHist :: GhcMonad m => (Int -> Int) -> m ([Name], Int, SrcSpan)
501 hsc_env <- getSession
502 case ic_resume (hsc_IC hsc_env) of
503 [] -> ghcError (ProgramError "not stopped at a breakpoint")
505 let ix = resumeHistoryIx r
506 history = resumeHistory r
509 when (new_ix > length history) $
510 ghcError (ProgramError "no more logged breakpoints")
512 ghcError (ProgramError "already at the beginning of the history")
515 update_ic apStack mb_info = do
516 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env
518 let ic = hsc_IC hsc_env1
519 r' = r { resumeHistoryIx = new_ix }
520 ic' = ic { ic_resume = r':rs }
522 modifySession (\_ -> hsc_env1{ hsc_IC = ic' })
524 return (names, new_ix, span)
526 -- careful: we want apStack to be the AP_STACK itself, not a thunk
527 -- around it, hence the cases are carefully constructed below to
528 -- make this the case. ToDo: this is v. fragile, do something better.
531 Resume { resumeApStack = apStack,
532 resumeBreakInfo = mb_info } ->
533 update_ic apStack mb_info
534 else case history !! (new_ix - 1) of
535 History apStack info _ ->
536 update_ic apStack (Just info)
538 -- -----------------------------------------------------------------------------
539 -- After stopping at a breakpoint, add free variables to the environment
540 result_fs :: FastString
541 result_fs = fsLit "_result"
543 bindLocalsAtBreakpoint
547 -> IO (HscEnv, [Name], SrcSpan)
549 -- Nothing case: we stopped when an exception was raised, not at a
550 -- breakpoint. We have no location information or local variables to
551 -- bind, all we can do is bind a local variable to the exception
553 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
554 let exn_fs = fsLit "_exception"
555 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
557 e_name = mkInternalName (getUnique e_fs) (mkTyVarOccFS e_fs) span
558 e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
559 exn_id = Id.mkVanillaGlobal exn_name (mkTyVarTy e_tyvar)
561 ictxt0 = hsc_IC hsc_env
562 ictxt1 = extendInteractiveContext ictxt0 [exn_id]
564 span = mkGeneralSrcSpan (fsLit "<exception thrown>")
566 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
567 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
569 -- Just case: we stopped at a breakpoint, we have information about the location
570 -- of the breakpoint and the free variables of the expression.
571 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
574 mod_name = moduleName (breakInfo_module info)
575 hmi = expectJust "bindLocalsAtBreakpoint" $
576 lookupUFM (hsc_HPT hsc_env) mod_name
577 breaks = getModBreaks hmi
578 index = breakInfo_number info
579 vars = breakInfo_vars info
580 result_ty = breakInfo_resty info
581 occs = modBreaks_vars breaks ! index
582 span = modBreaks_locs breaks ! index
584 -- filter out any unboxed ids; we can't bind these at the prompt
585 let pointers = filter (\(id,_) -> isPointer id) vars
586 isPointer id | PtrRep <- idPrimRep id = True
589 let (ids, offsets) = unzip pointers
591 -- It might be that getIdValFromApStack fails, because the AP_STACK
592 -- has been accidentally evaluated, or something else has gone wrong.
593 -- So that we don't fall over in a heap when this happens, just don't
594 -- bind any free variables instead, and we emit a warning.
595 mb_hValues <- mapM (getIdValFromApStack apStack) (map fromIntegral offsets)
596 let filtered_ids = [ id | (id, Just _hv) <- zip ids mb_hValues ]
597 when (any isNothing mb_hValues) $
598 debugTraceMsg (hsc_dflags hsc_env) 1 $
599 text "Warning: _result has been evaluated, some bindings have been lost"
601 new_ids <- zipWithM mkNewId occs filtered_ids
602 let names = map idName new_ids
604 -- make an Id for _result. We use the Unique of the FastString "_result";
605 -- we don't care about uniqueness here, because there will only be one
606 -- _result in scope at any time.
607 let result_name = mkInternalName (getUnique result_fs)
608 (mkVarOccFS result_fs) span
609 result_id = Id.mkVanillaGlobal result_name result_ty
611 -- for each Id we're about to bind in the local envt:
612 -- - tidy the type variables
613 -- - globalise the Id (Ids are supposed to be Global, apparently).
615 let result_ok = isPointer result_id
616 && not (isUnboxedTupleType (idType result_id))
618 all_ids | result_ok = result_id : new_ids
619 | otherwise = new_ids
620 id_tys = map idType all_ids
621 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
622 final_ids = zipWith setIdType all_ids tidy_tys
623 ictxt0 = hsc_IC hsc_env
624 ictxt1 = extendInteractiveContext ictxt0 final_ids
626 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
627 when result_ok $ Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
628 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
629 return (hsc_env1, if result_ok then result_name:names else names, span)
631 mkNewId :: OccName -> Id -> IO Id
633 us <- mkSplitUniqSupply 'I'
634 -- we need a fresh Unique for each Id we bind, because the linker
635 -- state is single-threaded and otherwise we'd spam old bindings
636 -- whenever we stop at a breakpoint. The InteractveContext is properly
637 -- saved/restored, but not the linker state. See #1743, test break026.
639 uniq = uniqFromSupply us
640 loc = nameSrcSpan (idName id)
641 name = mkInternalName uniq occ loc
643 new_id = Id.mkVanillaGlobalWithInfo name ty (idInfo id)
646 rttiEnvironment :: HscEnv -> IO HscEnv
647 rttiEnvironment hsc_env@HscEnv{hsc_IC=ic} = do
648 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
649 incompletelyTypedIds =
652 , (occNameFS.nameOccName.idName) id /= result_fs]
653 hsc_env' <- foldM improveTypes hsc_env (map idName incompletelyTypedIds)
656 noSkolems = isEmptyVarSet . tyVarsOfType . idType
657 improveTypes hsc_env@HscEnv{hsc_IC=ic} name = do
658 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
659 Just id = find (\i -> idName i == name) tmp_ids
663 mb_new_ty <- reconstructType hsc_env 10 id
664 let old_ty = idType id
666 Nothing -> return hsc_env
668 case improveRTTIType hsc_env old_ty new_ty of
670 WARN(True, text (":print failed to calculate the "
671 ++ "improvement for a type")) hsc_env
673 when (dopt Opt_D_dump_rtti (hsc_dflags hsc_env)) $
674 printForUser stderr alwaysQualify $
675 fsep [text "RTTI Improvement for", ppr id, equals, ppr subst]
677 let ic' = extendInteractiveContext
678 (substInteractiveContext ic subst) []
679 return hsc_env{hsc_IC=ic'}
681 getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
682 getIdValFromApStack apStack (I# stackDepth) = do
683 case getApStackVal# apStack (stackDepth +# 1#) of
684 -- The +1 is magic! I don't know where it comes
685 -- from, but this makes things line up. --SDM
688 0# -> return Nothing -- AP_STACK not found
689 _ -> return (Just (unsafeCoerce# result))
691 pushResume :: HscEnv -> Resume -> HscEnv
692 pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
694 ictxt0 = hsc_IC hsc_env
695 ictxt1 = ictxt0 { ic_resume = resume : ic_resume ictxt0 }
697 -- -----------------------------------------------------------------------------
698 -- Abandoning a resume context
700 abandon :: GhcMonad m => m Bool
702 hsc_env <- getSession
703 let ic = hsc_IC hsc_env
704 resume = ic_resume ic
708 modifySession $ \_ -> hsc_env{ hsc_IC = ic { ic_resume = rs } }
712 abandonAll :: GhcMonad m => m Bool
714 hsc_env <- getSession
715 let ic = hsc_IC hsc_env
716 resume = ic_resume ic
720 modifySession $ \_ -> hsc_env{ hsc_IC = ic { ic_resume = [] } }
721 liftIO $ mapM_ abandon_ rs
724 -- when abandoning a computation we have to
725 -- (a) kill the thread with an async exception, so that the
726 -- computation itself is stopped, and
727 -- (b) fill in the MVar. This step is necessary because any
728 -- thunks that were under evaluation will now be updated
729 -- with the partial computation, which still ends in takeMVar,
730 -- so any attempt to evaluate one of these thunks will block
731 -- unless we fill in the MVar.
732 -- See test break010.
733 abandon_ :: Resume -> IO ()
735 killThread (resumeThreadId r)
736 putMVar (resumeBreakMVar r) ()
738 -- -----------------------------------------------------------------------------
739 -- Bounded list, optimised for repeated cons
741 data BoundedList a = BL
742 {-# UNPACK #-} !Int -- length
743 {-# UNPACK #-} !Int -- bound
745 [a] -- right, list is (left ++ reverse right)
747 nilBL :: Int -> BoundedList a
748 nilBL bound = BL 0 bound [] []
750 consBL :: a -> BoundedList a -> BoundedList a
751 consBL a (BL len bound left right)
752 | len < bound = BL (len+1) bound (a:left) right
753 | null right = BL len bound [a] $! tail (reverse left)
754 | otherwise = BL len bound (a:left) $! tail right
756 toListBL :: BoundedList a -> [a]
757 toListBL (BL _ _ left right) = left ++ reverse right
759 fromListBL :: Int -> [a] -> BoundedList a
760 fromListBL bound l = BL (length l) bound l []
762 -- lenBL (BL len _ _ _) = len
764 -- -----------------------------------------------------------------------------
765 -- | Set the interactive evaluation context.
767 -- Setting the context doesn't throw away any bindings; the bindings
768 -- we've built up in the InteractiveContext simply move to the new
769 -- module. They always shadow anything in scope in the current context.
770 setContext :: GhcMonad m =>
771 [Module] -- ^ entire top level scope of these modules
772 -> [(Module, Maybe (ImportDecl RdrName))] -- ^ exports of these modules
774 setContext toplev_mods other_mods = do
775 hsc_env <- getSession
776 let old_ic = hsc_IC hsc_env
777 hpt = hsc_HPT hsc_env
778 (decls,mods) = partition (isJust . snd) other_mods -- time for tracing
779 export_mods = map fst mods
780 imprt_decls = map noLoc (catMaybes (map snd decls))
782 export_env <- liftIO $ mkExportEnv hsc_env export_mods
784 if null imprt_decls then return emptyGlobalRdrEnv else do
785 let this_mod | null toplev_mods = pRELUDE
786 | otherwise = head toplev_mods
787 liftIO $ hscRnImportDecls hsc_env this_mod imprt_decls
788 toplev_envs <- liftIO $ mapM (mkTopLevEnv hpt) toplev_mods
789 let all_env = foldr plusGlobalRdrEnv (plusGlobalRdrEnv export_env import_env) toplev_envs
790 modifySession $ \_ ->
791 hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
792 ic_exports = other_mods,
793 ic_rn_gbl_env = all_env }}
795 -- Make a GlobalRdrEnv based on the exports of the modules only.
796 mkExportEnv :: HscEnv -> [Module] -> IO GlobalRdrEnv
797 mkExportEnv hsc_env mods
798 = do { stuff <- mapM (getModuleExports hsc_env) mods
799 ; let (_msgs, mb_name_sets) = unzip stuff
800 envs = [ availsToGlobalRdrEnv (moduleName mod) avails
801 | (Just avails, mod) <- zip mb_name_sets mods ]
802 ; return $! foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs }
804 availsToGlobalRdrEnv :: ModuleName -> [AvailInfo] -> GlobalRdrEnv
805 availsToGlobalRdrEnv mod_name avails
806 = mkGlobalRdrEnv (gresFromAvails imp_prov avails)
808 -- We're building a GlobalRdrEnv as if the user imported
809 -- all the specified modules into the global interactive module
810 imp_prov = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
811 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
813 is_dloc = srcLocSpan interactiveSrcLoc }
815 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
817 = case lookupUFM hpt (moduleName modl) of
818 Nothing -> ghcError (ProgramError ("mkTopLevEnv: not a home module " ++
819 showSDoc (ppr modl)))
821 case mi_globals (hm_iface details) of
823 ghcError (ProgramError ("mkTopLevEnv: not interpreted "
824 ++ showSDoc (ppr modl)))
825 Just env -> return env
827 -- | Get the interactive evaluation context, consisting of a pair of the
828 -- set of modules from which we take the full top-level scope, and the set
829 -- of modules from which we take just the exports respectively.
830 getContext :: GhcMonad m => m ([Module],[(Module, Maybe (ImportDecl RdrName))])
831 getContext = withSession $ \HscEnv{ hsc_IC=ic } ->
832 return (ic_toplev_scope ic, ic_exports ic)
834 -- | Returns @True@ if the specified module is interpreted, and hence has
835 -- its full top-level scope available.
836 moduleIsInterpreted :: GhcMonad m => Module -> m Bool
837 moduleIsInterpreted modl = withSession $ \h ->
838 if modulePackageId modl /= thisPackage (hsc_dflags h)
840 else case lookupUFM (hsc_HPT h) (moduleName modl) of
841 Just details -> return (isJust (mi_globals (hm_iface details)))
842 _not_a_home_module -> return False
844 -- | Looks up an identifier in the current interactive context (for :info)
845 -- Filter the instances by the ones whose tycons (or clases resp)
846 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
847 -- The exact choice of which ones to show, and which to hide, is a judgement call.
849 getInfo :: GhcMonad m => Name -> m (Maybe (TyThing,Fixity,[Instance]))
851 = withSession $ \hsc_env ->
852 do mb_stuff <- liftIO $ hscTcRnGetInfo hsc_env name
854 Nothing -> return Nothing
855 Just (thing, fixity, ispecs) -> do
856 let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
857 return (Just (thing, fixity, filter (plausible rdr_env) ispecs))
859 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
860 = all ok $ nameSetToList $ tyClsNamesOfType $ idType $ instanceDFunId ispec
861 where -- A name is ok if it's in the rdr_env,
862 -- whether qualified or not
863 ok n | n == name = True -- The one we looked for in the first place!
864 | isBuiltInSyntax n = True
865 | isExternalName n = any ((== n) . gre_name)
866 (lookupGRE_Name rdr_env n)
869 -- | Returns all names in scope in the current interactive context
870 getNamesInScope :: GhcMonad m => m [Name]
871 getNamesInScope = withSession $ \hsc_env -> do
872 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
874 getRdrNamesInScope :: GhcMonad m => m [RdrName]
875 getRdrNamesInScope = withSession $ \hsc_env -> do
878 gbl_rdrenv = ic_rn_gbl_env ic
880 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
881 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
883 return (gbl_names ++ lcl_names)
886 -- ToDo: move to RdrName
887 greToRdrNames :: GlobalRdrElt -> [RdrName]
888 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
891 Imported specs -> concat (map do_spec (map is_decl specs))
893 occ = nameOccName name
896 | is_qual decl_spec = [qual]
897 | otherwise = [unqual,qual]
898 where qual = Qual (is_as decl_spec) occ
900 -- | Parses a string as an identifier, and returns the list of 'Name's that
901 -- the identifier can refer to in the current interactive context.
902 parseName :: GhcMonad m => String -> m [Name]
903 parseName str = withSession $ \hsc_env -> do
904 (L _ rdr_name) <- liftIO $ hscParseIdentifier hsc_env str
905 liftIO $ hscTcRnLookupRdrName hsc_env rdr_name
907 -- -----------------------------------------------------------------------------
908 -- Getting the type of an expression
910 -- | Get the type of an expression
911 exprType :: GhcMonad m => String -> m Type
912 exprType expr = withSession $ \hsc_env -> do
913 ty <- liftIO $ hscTcExpr hsc_env expr
914 return $ tidyType emptyTidyEnv ty
916 -- -----------------------------------------------------------------------------
917 -- Getting the kind of a type
919 -- | Get the kind of a type
920 typeKind :: GhcMonad m => String -> m Kind
921 typeKind str = withSession $ \hsc_env -> do
922 liftIO $ hscKcType hsc_env str
924 -----------------------------------------------------------------------------
925 -- cmCompileExpr: compile an expression and deliver an HValue
927 compileExpr :: GhcMonad m => String -> m HValue
928 compileExpr expr = withSession $ \hsc_env -> do
929 Just (ids, hval) <- liftIO $ hscStmt hsc_env ("let __cmCompileExpr = "++expr)
931 hvals <- liftIO (unsafeCoerce# hval :: IO [HValue])
934 ([_],[hv]) -> return hv
935 _ -> panic "compileExpr"
937 -- -----------------------------------------------------------------------------
938 -- Compile an expression into a dynamic
940 dynCompileExpr :: GhcMonad m => String -> m Dynamic
941 dynCompileExpr expr = do
942 (full,exports) <- getContext
945 (stringToPackageId "base") (mkModuleName "Data.Dynamic")
947 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
948 Just (ids, hvals) <- withSession $ \hsc_env ->
949 liftIO $ hscStmt hsc_env stmt
950 setContext full exports
951 vals <- liftIO (unsafeCoerce# hvals :: IO [Dynamic])
953 (_:[], v:[]) -> return v
954 _ -> panic "dynCompileExpr"
956 -----------------------------------------------------------------------------
957 -- show a module and it's source/object filenames
959 showModule :: GhcMonad m => ModSummary -> m String
960 showModule mod_summary =
961 withSession $ \hsc_env -> do
962 interpreted <- isModuleInterpreted mod_summary
963 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
965 isModuleInterpreted :: GhcMonad m => ModSummary -> m Bool
966 isModuleInterpreted mod_summary = withSession $ \hsc_env ->
967 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
968 Nothing -> panic "missing linkable"
969 Just mod_info -> return (not obj_linkable)
971 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
973 ----------------------------------------------------------------------------
976 obtainTermFromVal :: HscEnv -> Int -> Bool -> Type -> a -> IO Term
977 obtainTermFromVal hsc_env bound force ty x =
978 cvObtainTerm hsc_env bound force ty (unsafeCoerce# x)
980 obtainTermFromId :: HscEnv -> Int -> Bool -> Id -> IO Term
981 obtainTermFromId hsc_env bound force id = do
982 hv <- Linker.getHValue hsc_env (varName id)
983 cvObtainTerm hsc_env bound force (idType id) hv
985 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
986 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
987 reconstructType hsc_env bound id = do
988 hv <- Linker.getHValue hsc_env (varName id)
989 cvReconstructType hsc_env bound (idType id) hv