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"
40 import HscMain hiding (compileExpr)
41 import HsSyn (ImportDecl)
44 import TcRnMonad (initTc)
45 import RnNames (gresFromAvails, rnImports)
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 <- hscStmt hsc_env' expr
207 Nothing -> return RunFailed -- empty statement / comment
209 Just (ids, hval) -> do
210 -- XXX: This is the only place we can print warnings before the
211 -- result. Is this really the right thing to do? It's fine for
212 -- GHCi, but what's correct for other GHC API clients? We could
213 -- introduce a callback argument.
215 liftIO $ printBagOfWarnings dflags' warns
220 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
221 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
222 liftIO $ sandboxIO dflags' statusMVar thing_to_run
224 let ic = hsc_IC hsc_env
225 bindings = ic_tmp_ids ic
229 traceRunStatus expr bindings ids
230 breakMVar statusMVar status emptyHistory
232 handleRunStatus expr bindings ids
233 breakMVar statusMVar status emptyHistory
235 withVirtualCWD :: GhcMonad m => m a -> m a
236 withVirtualCWD m = do
237 hsc_env <- getSession
238 let ic = hsc_IC hsc_env
241 dir <- liftIO $ getCurrentDirectory
243 Just dir -> liftIO $ setCurrentDirectory dir
247 reset_cwd orig_dir = do
248 virt_dir <- liftIO $ getCurrentDirectory
249 hsc_env <- getSession
250 let old_IC = hsc_IC hsc_env
251 setSession hsc_env{ hsc_IC = old_IC{ ic_cwd = Just virt_dir } }
252 liftIO $ setCurrentDirectory orig_dir
254 gbracket set_cwd reset_cwd $ \_ -> m
256 parseImportDecl :: GhcMonad m => String -> m (ImportDecl RdrName)
257 parseImportDecl expr = withSession $ \hsc_env -> hscImport hsc_env expr
259 emptyHistory :: BoundedList History
260 emptyHistory = nilBL 50 -- keep a log of length 50
262 handleRunStatus :: GhcMonad m =>
263 String-> [Id] -> [Id]
264 -> MVar () -> MVar Status -> Status -> BoundedList History
266 handleRunStatus expr bindings final_ids breakMVar statusMVar status
269 -- did we hit a breakpoint or did we complete?
270 (Break is_exception apStack info tid) -> do
271 hsc_env <- getSession
272 let mb_info | is_exception = Nothing
273 | otherwise = Just info
274 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env apStack
277 resume = Resume { resumeStmt = expr, resumeThreadId = tid
278 , resumeBreakMVar = breakMVar, resumeStatMVar = statusMVar
279 , resumeBindings = bindings, resumeFinalIds = final_ids
280 , resumeApStack = apStack, resumeBreakInfo = mb_info
281 , resumeSpan = span, resumeHistory = toListBL history
282 , resumeHistoryIx = 0 }
283 hsc_env2 = pushResume hsc_env1 resume
285 modifySession (\_ -> hsc_env2)
286 return (RunBreak tid names mb_info)
287 (Complete either_hvals) ->
289 Left e -> return (RunException e)
291 hsc_env <- getSession
292 let final_ic = extendInteractiveContext (hsc_IC hsc_env) final_ids
293 final_names = map idName final_ids
294 liftIO $ Linker.extendLinkEnv (zip final_names hvals)
295 hsc_env' <- liftIO $ rttiEnvironment hsc_env{hsc_IC=final_ic}
296 modifySession (\_ -> hsc_env')
297 return (RunOk final_names)
299 traceRunStatus :: GhcMonad m =>
300 String -> [Id] -> [Id]
301 -> MVar () -> MVar Status -> Status -> BoundedList History
303 traceRunStatus expr bindings final_ids
304 breakMVar statusMVar status history = do
305 hsc_env <- getSession
307 -- when tracing, if we hit a breakpoint that is not explicitly
308 -- enabled, then we just log the event in the history and continue.
309 (Break is_exception apStack info tid) | not is_exception -> do
310 b <- liftIO $ isBreakEnabled hsc_env info
314 let history' = mkHistory hsc_env apStack info `consBL` history
315 -- probably better make history strict here, otherwise
316 -- our BoundedList will be pointless.
317 _ <- liftIO $ evaluate history'
319 withBreakAction True (hsc_dflags hsc_env)
320 breakMVar statusMVar $ do
321 liftIO $ withInterruptsSentTo tid $ do
322 putMVar breakMVar () -- awaken the stopped thread
323 takeMVar statusMVar -- and wait for the result
324 traceRunStatus expr bindings final_ids
325 breakMVar statusMVar status history'
329 handle_normally = handleRunStatus expr bindings final_ids
330 breakMVar statusMVar status history
333 isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
334 isBreakEnabled hsc_env inf =
335 case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
337 w <- getBreak (modBreaks_flags (getModBreaks hmi))
338 (breakInfo_number inf)
339 case w of Just n -> return (n /= 0); _other -> return False
344 foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
345 foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
348 setStepFlag = poke stepFlag 1
349 resetStepFlag :: IO ()
350 resetStepFlag = poke stepFlag 0
352 -- this points to the IO action that is executed when a breakpoint is hit
353 foreign import ccall "&rts_breakpoint_io_action"
354 breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
356 -- When running a computation, we redirect ^C exceptions to the running
357 -- thread. ToDo: we might want a way to continue even if the target
358 -- thread doesn't die when it receives the exception... "this thread
359 -- is not responding".
361 -- Careful here: there may be ^C exceptions flying around, so we start the new
362 -- thread blocked (forkIO inherits mask from the parent, #1048), and unblock
363 -- only while we execute the user's code. We can't afford to lose the final
364 -- putMVar, otherwise deadlock ensues. (#1583, #1922, #1946)
365 sandboxIO :: DynFlags -> MVar Status -> IO [HValue] -> IO Status
366 sandboxIO dflags statusMVar thing =
367 mask $ \restore -> -- fork starts blocked
368 let runIt = liftM Complete $ try (restore $ rethrow dflags thing)
369 in if dopt Opt_GhciSandbox dflags
370 then do tid <- forkIO $ do res <- runIt
371 putMVar statusMVar res -- empty: can't block
372 withInterruptsSentTo tid $ takeMVar statusMVar
373 else -- GLUT on OS X needs to run on the main thread. If you
374 -- try to use it from another thread then you just get a
375 -- white rectangle rendered. For this, or anything else
376 -- with such restrictions, you can turn the GHCi sandbox off
377 -- and things will be run in the main thread.
380 -- We want to turn ^C into a break when -fbreak-on-exception is on,
381 -- but it's an async exception and we only break for sync exceptions.
382 -- Idea: if we catch and re-throw it, then the re-throw will trigger
383 -- a break. Great - but we don't want to re-throw all exceptions, because
384 -- then we'll get a double break for ordinary sync exceptions (you'd have
385 -- to :continue twice, which looks strange). So if the exception is
386 -- not "Interrupted", we unset the exception flag before throwing.
388 rethrow :: DynFlags -> IO a -> IO a
389 rethrow dflags io = Exception.catch io $ \se -> do
390 -- If -fbreak-on-error, we break unconditionally,
391 -- but with care of not breaking twice
392 if dopt Opt_BreakOnError dflags &&
393 not (dopt Opt_BreakOnException dflags)
394 then poke exceptionFlag 1
395 else case fromException se of
396 -- If it is a "UserInterrupt" exception, we allow
397 -- a possible break by way of -fbreak-on-exception
398 Just UserInterrupt -> return ()
399 -- In any other case, we don't want to break
400 _ -> poke exceptionFlag 0
404 withInterruptsSentTo :: ThreadId -> IO r -> IO r
405 withInterruptsSentTo thread get_result = do
406 bracket (modifyMVar_ interruptTargetThread (return . (thread:)))
407 (\_ -> modifyMVar_ interruptTargetThread (\tl -> return $! tail tl))
410 -- This function sets up the interpreter for catching breakpoints, and
411 -- resets everything when the computation has stopped running. This
412 -- is a not-very-good way to ensure that only the interactive
413 -- evaluation should generate breakpoints.
414 withBreakAction :: (ExceptionMonad m, MonadIO m) =>
415 Bool -> DynFlags -> MVar () -> MVar Status -> m a -> m a
416 withBreakAction step dflags breakMVar statusMVar act
417 = gbracket (liftIO setBreakAction) (liftIO . resetBreakAction) (\_ -> act)
420 stablePtr <- newStablePtr onBreak
421 poke breakPointIOAction stablePtr
422 when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
423 when step $ setStepFlag
425 -- Breaking on exceptions is not enabled by default, since it
426 -- might be a bit surprising. The exception flag is turned off
427 -- as soon as it is hit, or in resetBreakAction below.
429 onBreak is_exception info apStack = do
431 putMVar statusMVar (Break is_exception apStack info tid)
434 resetBreakAction stablePtr = do
435 poke breakPointIOAction noBreakStablePtr
438 freeStablePtr stablePtr
440 noBreakStablePtr :: StablePtr (Bool -> BreakInfo -> HValue -> IO ())
441 noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
443 noBreakAction :: Bool -> BreakInfo -> HValue -> IO ()
444 noBreakAction False _ _ = putStrLn "*** Ignoring breakpoint"
445 noBreakAction True _ _ = return () -- exception: just continue
447 resume :: GhcMonad m => (SrcSpan->Bool) -> SingleStep -> m RunResult
448 resume canLogSpan step
450 hsc_env <- getSession
451 let ic = hsc_IC hsc_env
452 resume = ic_resume ic
455 [] -> ghcError (ProgramError "not stopped at a breakpoint")
457 -- unbind the temporary locals by restoring the TypeEnv from
458 -- before the breakpoint, and drop this Resume from the
459 -- InteractiveContext.
460 let resume_tmp_ids = resumeBindings r
461 ic' = ic { ic_tmp_ids = resume_tmp_ids,
463 modifySession (\_ -> hsc_env{ hsc_IC = ic' })
465 -- remove any bindings created since the breakpoint from the
466 -- linker's environment
467 let new_names = map idName (filter (`notElem` resume_tmp_ids)
469 liftIO $ Linker.deleteFromLinkEnv new_names
471 when (isStep step) $ liftIO setStepFlag
473 Resume { resumeStmt = expr, resumeThreadId = tid
474 , resumeBreakMVar = breakMVar, resumeStatMVar = statusMVar
475 , resumeBindings = bindings, resumeFinalIds = final_ids
476 , resumeApStack = apStack, resumeBreakInfo = info, resumeSpan = span
477 , resumeHistory = hist } -> do
479 withBreakAction (isStep step) (hsc_dflags hsc_env)
480 breakMVar statusMVar $ do
481 status <- liftIO $ withInterruptsSentTo tid $ do
483 -- this awakens the stopped thread...
485 -- and wait for the result
486 let prevHistoryLst = fromListBL 50 hist
488 Nothing -> prevHistoryLst
490 | not $canLogSpan span -> prevHistoryLst
491 | otherwise -> mkHistory hsc_env apStack i `consBL`
495 traceRunStatus expr bindings final_ids
496 breakMVar statusMVar status hist'
498 handleRunStatus expr bindings final_ids
499 breakMVar statusMVar status hist'
501 back :: GhcMonad m => m ([Name], Int, SrcSpan)
504 forward :: GhcMonad m => m ([Name], Int, SrcSpan)
505 forward = moveHist (subtract 1)
507 moveHist :: GhcMonad m => (Int -> Int) -> m ([Name], Int, SrcSpan)
509 hsc_env <- getSession
510 case ic_resume (hsc_IC hsc_env) of
511 [] -> ghcError (ProgramError "not stopped at a breakpoint")
513 let ix = resumeHistoryIx r
514 history = resumeHistory r
517 when (new_ix > length history) $
518 ghcError (ProgramError "no more logged breakpoints")
520 ghcError (ProgramError "already at the beginning of the history")
523 update_ic apStack mb_info = do
524 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env
526 let ic = hsc_IC hsc_env1
527 r' = r { resumeHistoryIx = new_ix }
528 ic' = ic { ic_resume = r':rs }
530 modifySession (\_ -> hsc_env1{ hsc_IC = ic' })
532 return (names, new_ix, span)
534 -- careful: we want apStack to be the AP_STACK itself, not a thunk
535 -- around it, hence the cases are carefully constructed below to
536 -- make this the case. ToDo: this is v. fragile, do something better.
539 Resume { resumeApStack = apStack,
540 resumeBreakInfo = mb_info } ->
541 update_ic apStack mb_info
542 else case history !! (new_ix - 1) of
543 History apStack info _ ->
544 update_ic apStack (Just info)
546 -- -----------------------------------------------------------------------------
547 -- After stopping at a breakpoint, add free variables to the environment
548 result_fs :: FastString
549 result_fs = fsLit "_result"
551 bindLocalsAtBreakpoint
555 -> IO (HscEnv, [Name], SrcSpan)
557 -- Nothing case: we stopped when an exception was raised, not at a
558 -- breakpoint. We have no location information or local variables to
559 -- bind, all we can do is bind a local variable to the exception
561 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
562 let exn_fs = fsLit "_exception"
563 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
565 e_name = mkInternalName (getUnique e_fs) (mkTyVarOccFS e_fs) span
566 e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
567 exn_id = Id.mkVanillaGlobal exn_name (mkTyVarTy e_tyvar)
569 ictxt0 = hsc_IC hsc_env
570 ictxt1 = extendInteractiveContext ictxt0 [exn_id]
572 span = mkGeneralSrcSpan (fsLit "<exception thrown>")
574 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
575 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
577 -- Just case: we stopped at a breakpoint, we have information about the location
578 -- of the breakpoint and the free variables of the expression.
579 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
582 mod_name = moduleName (breakInfo_module info)
583 hmi = expectJust "bindLocalsAtBreakpoint" $
584 lookupUFM (hsc_HPT hsc_env) mod_name
585 breaks = getModBreaks hmi
586 index = breakInfo_number info
587 vars = breakInfo_vars info
588 result_ty = breakInfo_resty info
589 occs = modBreaks_vars breaks ! index
590 span = modBreaks_locs breaks ! index
592 -- filter out any unboxed ids; we can't bind these at the prompt
593 let pointers = filter (\(id,_) -> isPointer id) vars
594 isPointer id | PtrRep <- idPrimRep id = True
597 let (ids, offsets) = unzip pointers
599 -- It might be that getIdValFromApStack fails, because the AP_STACK
600 -- has been accidentally evaluated, or something else has gone wrong.
601 -- So that we don't fall over in a heap when this happens, just don't
602 -- bind any free variables instead, and we emit a warning.
603 mb_hValues <- mapM (getIdValFromApStack apStack) (map fromIntegral offsets)
604 let filtered_ids = [ id | (id, Just _hv) <- zip ids mb_hValues ]
605 when (any isNothing mb_hValues) $
606 debugTraceMsg (hsc_dflags hsc_env) 1 $
607 text "Warning: _result has been evaluated, some bindings have been lost"
609 new_ids <- zipWithM mkNewId occs filtered_ids
610 let names = map idName new_ids
612 -- make an Id for _result. We use the Unique of the FastString "_result";
613 -- we don't care about uniqueness here, because there will only be one
614 -- _result in scope at any time.
615 let result_name = mkInternalName (getUnique result_fs)
616 (mkVarOccFS result_fs) span
617 result_id = Id.mkVanillaGlobal result_name result_ty
619 -- for each Id we're about to bind in the local envt:
620 -- - tidy the type variables
621 -- - globalise the Id (Ids are supposed to be Global, apparently).
623 let result_ok = isPointer result_id
624 && not (isUnboxedTupleType (idType result_id))
626 all_ids | result_ok = result_id : new_ids
627 | otherwise = new_ids
628 id_tys = map idType all_ids
629 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
630 final_ids = zipWith setIdType all_ids tidy_tys
631 ictxt0 = hsc_IC hsc_env
632 ictxt1 = extendInteractiveContext ictxt0 final_ids
634 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
635 when result_ok $ Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
636 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
637 return (hsc_env1, if result_ok then result_name:names else names, span)
639 mkNewId :: OccName -> Id -> IO Id
641 us <- mkSplitUniqSupply 'I'
642 -- we need a fresh Unique for each Id we bind, because the linker
643 -- state is single-threaded and otherwise we'd spam old bindings
644 -- whenever we stop at a breakpoint. The InteractveContext is properly
645 -- saved/restored, but not the linker state. See #1743, test break026.
647 uniq = uniqFromSupply us
648 loc = nameSrcSpan (idName id)
649 name = mkInternalName uniq occ loc
651 new_id = Id.mkVanillaGlobalWithInfo name ty (idInfo id)
654 rttiEnvironment :: HscEnv -> IO HscEnv
655 rttiEnvironment hsc_env@HscEnv{hsc_IC=ic} = do
656 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
657 incompletelyTypedIds =
660 , (occNameFS.nameOccName.idName) id /= result_fs]
661 hsc_env' <- foldM improveTypes hsc_env (map idName incompletelyTypedIds)
664 noSkolems = isEmptyVarSet . tyVarsOfType . idType
665 improveTypes hsc_env@HscEnv{hsc_IC=ic} name = do
666 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
667 Just id = find (\i -> idName i == name) tmp_ids
671 mb_new_ty <- reconstructType hsc_env 10 id
672 let old_ty = idType id
674 Nothing -> return hsc_env
676 case improveRTTIType hsc_env old_ty new_ty of
678 WARN(True, text (":print failed to calculate the "
679 ++ "improvement for a type")) hsc_env
681 when (dopt Opt_D_dump_rtti (hsc_dflags hsc_env)) $
682 printForUser stderr alwaysQualify $
683 fsep [text "RTTI Improvement for", ppr id, equals, ppr subst]
685 let ic' = extendInteractiveContext
686 (substInteractiveContext ic subst) []
687 return hsc_env{hsc_IC=ic'}
689 getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
690 getIdValFromApStack apStack (I# stackDepth) = do
691 case getApStackVal# apStack (stackDepth +# 1#) of
692 -- The +1 is magic! I don't know where it comes
693 -- from, but this makes things line up. --SDM
696 0# -> return Nothing -- AP_STACK not found
697 _ -> return (Just (unsafeCoerce# result))
699 pushResume :: HscEnv -> Resume -> HscEnv
700 pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
702 ictxt0 = hsc_IC hsc_env
703 ictxt1 = ictxt0 { ic_resume = resume : ic_resume ictxt0 }
705 -- -----------------------------------------------------------------------------
706 -- Abandoning a resume context
708 abandon :: GhcMonad m => m Bool
710 hsc_env <- getSession
711 let ic = hsc_IC hsc_env
712 resume = ic_resume ic
716 modifySession $ \_ -> hsc_env{ hsc_IC = ic { ic_resume = rs } }
720 abandonAll :: GhcMonad m => m Bool
722 hsc_env <- getSession
723 let ic = hsc_IC hsc_env
724 resume = ic_resume ic
728 modifySession $ \_ -> hsc_env{ hsc_IC = ic { ic_resume = [] } }
729 liftIO $ mapM_ abandon_ rs
732 -- when abandoning a computation we have to
733 -- (a) kill the thread with an async exception, so that the
734 -- computation itself is stopped, and
735 -- (b) fill in the MVar. This step is necessary because any
736 -- thunks that were under evaluation will now be updated
737 -- with the partial computation, which still ends in takeMVar,
738 -- so any attempt to evaluate one of these thunks will block
739 -- unless we fill in the MVar.
740 -- See test break010.
741 abandon_ :: Resume -> IO ()
743 killThread (resumeThreadId r)
744 putMVar (resumeBreakMVar r) ()
746 -- -----------------------------------------------------------------------------
747 -- Bounded list, optimised for repeated cons
749 data BoundedList a = BL
750 {-# UNPACK #-} !Int -- length
751 {-# UNPACK #-} !Int -- bound
753 [a] -- right, list is (left ++ reverse right)
755 nilBL :: Int -> BoundedList a
756 nilBL bound = BL 0 bound [] []
758 consBL :: a -> BoundedList a -> BoundedList a
759 consBL a (BL len bound left right)
760 | len < bound = BL (len+1) bound (a:left) right
761 | null right = BL len bound [a] $! tail (reverse left)
762 | otherwise = BL len bound (a:left) $! tail right
764 toListBL :: BoundedList a -> [a]
765 toListBL (BL _ _ left right) = left ++ reverse right
767 fromListBL :: Int -> [a] -> BoundedList a
768 fromListBL bound l = BL (length l) bound l []
770 -- lenBL (BL len _ _ _) = len
772 -- -----------------------------------------------------------------------------
773 -- | Set the interactive evaluation context.
775 -- Setting the context doesn't throw away any bindings; the bindings
776 -- we've built up in the InteractiveContext simply move to the new
777 -- module. They always shadow anything in scope in the current context.
778 setContext :: GhcMonad m =>
779 [Module] -- ^ entire top level scope of these modules
780 -> [(Module, Maybe (ImportDecl RdrName))] -- ^ exports of these modules
782 setContext toplev_mods other_mods = do
783 hsc_env <- getSession
784 let old_ic = hsc_IC hsc_env
785 hpt = hsc_HPT hsc_env
786 (decls,mods) = partition (isJust . snd) other_mods -- time for tracing
787 export_mods = map fst mods
788 imprt_decls = map noLoc (catMaybes (map snd decls))
790 export_env <- liftIO $ mkExportEnv hsc_env export_mods
792 if null imprt_decls then return emptyGlobalRdrEnv else do
793 let imports = rnImports imprt_decls
794 this_mod = if null toplev_mods then pRELUDE else head toplev_mods
796 ioMsgMaybe $ liftIO $ initTc hsc_env HsSrcFile False this_mod imports
798 toplev_envs <- liftIO $ mapM (mkTopLevEnv hpt) toplev_mods
799 let all_env = foldr plusGlobalRdrEnv (plusGlobalRdrEnv export_env import_env) toplev_envs
800 modifySession $ \_ ->
801 hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
802 ic_exports = other_mods,
803 ic_rn_gbl_env = all_env }}
805 -- Make a GlobalRdrEnv based on the exports of the modules only.
806 mkExportEnv :: HscEnv -> [Module] -> IO GlobalRdrEnv
807 mkExportEnv hsc_env mods
808 = do { stuff <- mapM (getModuleExports hsc_env) mods
809 ; let (_msgs, mb_name_sets) = unzip stuff
810 envs = [ availsToGlobalRdrEnv (moduleName mod) avails
811 | (Just avails, mod) <- zip mb_name_sets mods ]
812 ; return $! foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs }
814 availsToGlobalRdrEnv :: ModuleName -> [AvailInfo] -> GlobalRdrEnv
815 availsToGlobalRdrEnv mod_name avails
816 = mkGlobalRdrEnv (gresFromAvails imp_prov avails)
818 -- We're building a GlobalRdrEnv as if the user imported
819 -- all the specified modules into the global interactive module
820 imp_prov = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
821 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
823 is_dloc = srcLocSpan interactiveSrcLoc }
825 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
827 = case lookupUFM hpt (moduleName modl) of
828 Nothing -> ghcError (ProgramError ("mkTopLevEnv: not a home module " ++
829 showSDoc (ppr modl)))
831 case mi_globals (hm_iface details) of
833 ghcError (ProgramError ("mkTopLevEnv: not interpreted "
834 ++ showSDoc (ppr modl)))
835 Just env -> return env
837 -- | Get the interactive evaluation context, consisting of a pair of the
838 -- set of modules from which we take the full top-level scope, and the set
839 -- of modules from which we take just the exports respectively.
840 getContext :: GhcMonad m => m ([Module],[(Module, Maybe (ImportDecl RdrName))])
841 getContext = withSession $ \HscEnv{ hsc_IC=ic } ->
842 return (ic_toplev_scope ic, ic_exports ic)
844 -- | Returns @True@ if the specified module is interpreted, and hence has
845 -- its full top-level scope available.
846 moduleIsInterpreted :: GhcMonad m => Module -> m Bool
847 moduleIsInterpreted modl = withSession $ \h ->
848 if modulePackageId modl /= thisPackage (hsc_dflags h)
850 else case lookupUFM (hsc_HPT h) (moduleName modl) of
851 Just details -> return (isJust (mi_globals (hm_iface details)))
852 _not_a_home_module -> return False
854 -- | Looks up an identifier in the current interactive context (for :info)
855 -- Filter the instances by the ones whose tycons (or clases resp)
856 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
857 -- The exact choice of which ones to show, and which to hide, is a judgement call.
859 getInfo :: GhcMonad m => Name -> m (Maybe (TyThing,Fixity,[Instance]))
861 = withSession $ \hsc_env ->
862 do mb_stuff <- ioMsg $ tcRnGetInfo hsc_env name
864 Nothing -> return Nothing
865 Just (thing, fixity, ispecs) -> do
866 let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
867 return (Just (thing, fixity, filter (plausible rdr_env) ispecs))
869 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
870 = all ok $ nameSetToList $ tyClsNamesOfType $ idType $ instanceDFunId ispec
871 where -- A name is ok if it's in the rdr_env,
872 -- whether qualified or not
873 ok n | n == name = True -- The one we looked for in the first place!
874 | isBuiltInSyntax n = True
875 | isExternalName n = any ((== n) . gre_name)
876 (lookupGRE_Name rdr_env n)
879 -- | Returns all names in scope in the current interactive context
880 getNamesInScope :: GhcMonad m => m [Name]
881 getNamesInScope = withSession $ \hsc_env -> do
882 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
884 getRdrNamesInScope :: GhcMonad m => m [RdrName]
885 getRdrNamesInScope = withSession $ \hsc_env -> do
888 gbl_rdrenv = ic_rn_gbl_env ic
890 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
891 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
893 return (gbl_names ++ lcl_names)
896 -- ToDo: move to RdrName
897 greToRdrNames :: GlobalRdrElt -> [RdrName]
898 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
901 Imported specs -> concat (map do_spec (map is_decl specs))
903 occ = nameOccName name
906 | is_qual decl_spec = [qual]
907 | otherwise = [unqual,qual]
908 where qual = Qual (is_as decl_spec) occ
910 -- | Parses a string as an identifier, and returns the list of 'Name's that
911 -- the identifier can refer to in the current interactive context.
912 parseName :: GhcMonad m => String -> m [Name]
913 parseName str = withSession $ \hsc_env -> do
914 (L _ rdr_name) <- hscParseIdentifier (hsc_dflags hsc_env) str
915 ioMsgMaybe $ tcRnLookupRdrName hsc_env rdr_name
917 -- -----------------------------------------------------------------------------
918 -- Getting the type of an expression
920 -- | Get the type of an expression
921 exprType :: GhcMonad m => String -> m Type
922 exprType expr = withSession $ \hsc_env -> do
923 ty <- hscTcExpr hsc_env expr
924 return $ tidyType emptyTidyEnv ty
926 -- -----------------------------------------------------------------------------
927 -- Getting the kind of a type
929 -- | Get the kind of a type
930 typeKind :: GhcMonad m => String -> m Kind
931 typeKind str = withSession $ \hsc_env -> do
932 hscKcType hsc_env str
934 -----------------------------------------------------------------------------
935 -- cmCompileExpr: compile an expression and deliver an HValue
937 compileExpr :: GhcMonad m => String -> m HValue
938 compileExpr expr = withSession $ \hsc_env -> do
939 Just (ids, hval) <- hscStmt hsc_env ("let __cmCompileExpr = "++expr)
941 hvals <- liftIO (unsafeCoerce# hval :: IO [HValue])
944 ([_],[hv]) -> return hv
945 _ -> panic "compileExpr"
947 -- -----------------------------------------------------------------------------
948 -- Compile an expression into a dynamic
950 dynCompileExpr :: GhcMonad m => String -> m Dynamic
951 dynCompileExpr expr = do
952 (full,exports) <- getContext
955 (stringToPackageId "base") (mkModuleName "Data.Dynamic")
957 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
958 Just (ids, hvals) <- withSession (flip hscStmt stmt)
959 setContext full exports
960 vals <- liftIO (unsafeCoerce# hvals :: IO [Dynamic])
962 (_:[], v:[]) -> return v
963 _ -> panic "dynCompileExpr"
965 -----------------------------------------------------------------------------
966 -- show a module and it's source/object filenames
968 showModule :: GhcMonad m => ModSummary -> m String
969 showModule mod_summary =
970 withSession $ \hsc_env -> do
971 interpreted <- isModuleInterpreted mod_summary
972 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
974 isModuleInterpreted :: GhcMonad m => ModSummary -> m Bool
975 isModuleInterpreted mod_summary = withSession $ \hsc_env ->
976 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
977 Nothing -> panic "missing linkable"
978 Just mod_info -> return (not obj_linkable)
980 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
982 ----------------------------------------------------------------------------
985 obtainTermFromVal :: HscEnv -> Int -> Bool -> Type -> a -> IO Term
986 obtainTermFromVal hsc_env bound force ty x =
987 cvObtainTerm hsc_env bound force ty (unsafeCoerce# x)
989 obtainTermFromId :: HscEnv -> Int -> Bool -> Id -> IO Term
990 obtainTermFromId hsc_env bound force id = do
991 hv <- Linker.getHValue hsc_env (varName id)
992 cvObtainTerm hsc_env bound force (idType id) hv
994 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
995 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
996 reconstructType hsc_env bound id = do
997 hv <- Linker.getHValue hsc_env (varName id)
998 cvReconstructType hsc_env bound (idType id) hv