1 -- -----------------------------------------------------------------------------
3 -- (c) The University of Glasgow, 2005-2007
5 -- Running statements interactively
7 -- -----------------------------------------------------------------------------
9 module InteractiveEval (
11 RunResult(..), Status(..), Resume(..), History(..),
12 runStmt, runStmtWithLocation,
13 parseImportDecl, SingleStep(..),
21 setContext, getContext,
32 compileExpr, dynCompileExpr,
33 Term(..), obtainTermFromId, obtainTermFromVal, reconstructType
39 #include "HsVersions.h"
45 import RnNames (gresFromAvails)
48 import TcType hiding( typeKind )
51 import Name hiding ( varName )
54 import PrelNames (pRELUDE)
69 import RtClosureInspect
74 import System.Directory
76 import Data.List (find)
78 import Foreign hiding (unsafePerformIO)
83 import Control.Concurrent
84 -- import Foreign.StablePtr
86 import System.IO.Unsafe
88 -- -----------------------------------------------------------------------------
89 -- running a statement interactively
92 = RunOk [Name] -- ^ names bound by this evaluation
93 | RunFailed -- ^ statement failed compilation
94 | RunException SomeException -- ^ statement raised an exception
95 | RunBreak ThreadId [Name] (Maybe BreakInfo)
98 = Break Bool HValue BreakInfo ThreadId
99 -- ^ the computation hit a breakpoint (Bool <=> was an exception)
100 | Complete (Either SomeException [HValue])
101 -- ^ the computation completed with either an exception or a value
105 resumeStmt :: String, -- the original statement
106 resumeThreadId :: ThreadId, -- thread running the computation
107 resumeBreakMVar :: MVar (),
108 resumeStatMVar :: MVar Status,
109 resumeBindings :: [Id],
110 resumeFinalIds :: [Id], -- [Id] to bind on completion
111 resumeApStack :: HValue, -- The object from which we can get
112 -- value of the free variables.
113 resumeBreakInfo :: Maybe BreakInfo,
114 -- the breakpoint we stopped at
115 -- (Nothing <=> exception)
116 resumeSpan :: SrcSpan, -- just a cache, otherwise it's a pain
117 -- to fetch the ModDetails & ModBreaks
119 resumeHistory :: [History],
120 resumeHistoryIx :: Int -- 0 <==> at the top of the history
123 getResumeContext :: GhcMonad m => m [Resume]
124 getResumeContext = withSession (return . ic_resume . hsc_IC)
131 isStep :: SingleStep -> Bool
132 isStep RunToCompletion = False
137 historyApStack :: HValue,
138 historyBreakInfo :: BreakInfo,
139 historyEnclosingDecls :: [String] -- declarations enclosing the breakpoint
142 mkHistory :: HscEnv -> HValue -> BreakInfo -> History
143 mkHistory hsc_env hval bi = let
144 decls = findEnclosingDecls hsc_env bi
145 in History hval bi decls
148 getHistoryModule :: History -> Module
149 getHistoryModule = breakInfo_module . historyBreakInfo
151 getHistorySpan :: HscEnv -> History -> SrcSpan
152 getHistorySpan hsc_env hist =
153 let inf = historyBreakInfo hist
154 num = breakInfo_number inf
155 in case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
156 Just hmi -> modBreaks_locs (getModBreaks hmi) ! num
157 _ -> panic "getHistorySpan"
159 getModBreaks :: HomeModInfo -> ModBreaks
161 | Just linkable <- hm_linkable hmi,
162 [BCOs _ modBreaks] <- linkableUnlinked linkable
165 = emptyModBreaks -- probably object code
167 {- | Finds the enclosing top level function name -}
168 -- ToDo: a better way to do this would be to keep hold of the decl_path computed
169 -- by the coverage pass, which gives the list of lexically-enclosing bindings
171 findEnclosingDecls :: HscEnv -> BreakInfo -> [String]
172 findEnclosingDecls hsc_env inf =
173 let hmi = expectJust "findEnclosingDecls" $
174 lookupUFM (hsc_HPT hsc_env) (moduleName $ breakInfo_module inf)
175 mb = getModBreaks hmi
176 in modBreaks_decls mb ! breakInfo_number inf
179 -- | Run a statement in the current interactive context. Statement
180 -- may bind multple values.
181 runStmt :: GhcMonad m => String -> SingleStep -> m RunResult
182 runStmt = runStmtWithLocation "<interactive>" 1
184 -- | Run a statement in the current interactive context. Passing debug information
185 -- Statement may bind multple values.
186 runStmtWithLocation :: GhcMonad m => String -> Int ->
187 String -> SingleStep -> m RunResult
188 runStmtWithLocation source linenumber expr step =
190 hsc_env <- getSession
192 breakMVar <- liftIO $ newEmptyMVar -- wait on this when we hit a breakpoint
193 statusMVar <- liftIO $ 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 r <- liftIO $ hscStmtWithLocation hsc_env' expr source linenumber
203 Nothing -> return RunFailed -- empty statement / comment
205 Just (ids, hval) -> do
208 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
209 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
210 liftIO $ sandboxIO dflags' statusMVar thing_to_run
212 let ic = hsc_IC hsc_env
213 bindings = ic_tmp_ids ic
217 traceRunStatus expr bindings ids
218 breakMVar statusMVar status emptyHistory
220 handleRunStatus expr bindings ids
221 breakMVar statusMVar status emptyHistory
223 withVirtualCWD :: GhcMonad m => m a -> m a
224 withVirtualCWD m = do
225 hsc_env <- getSession
226 let ic = hsc_IC hsc_env
229 dir <- liftIO $ getCurrentDirectory
231 Just dir -> liftIO $ setCurrentDirectory dir
235 reset_cwd orig_dir = do
236 virt_dir <- liftIO $ getCurrentDirectory
237 hsc_env <- getSession
238 let old_IC = hsc_IC hsc_env
239 setSession hsc_env{ hsc_IC = old_IC{ ic_cwd = Just virt_dir } }
240 liftIO $ setCurrentDirectory orig_dir
242 gbracket set_cwd reset_cwd $ \_ -> m
244 parseImportDecl :: GhcMonad m => String -> m (ImportDecl RdrName)
245 parseImportDecl expr = withSession $ \hsc_env -> liftIO $ hscImport hsc_env expr
247 emptyHistory :: BoundedList History
248 emptyHistory = nilBL 50 -- keep a log of length 50
250 handleRunStatus :: GhcMonad m =>
251 String-> [Id] -> [Id]
252 -> MVar () -> MVar Status -> Status -> BoundedList History
254 handleRunStatus expr bindings final_ids breakMVar statusMVar status
257 -- did we hit a breakpoint or did we complete?
258 (Break is_exception apStack info tid) -> do
259 hsc_env <- getSession
260 let mb_info | is_exception = Nothing
261 | otherwise = Just info
262 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env apStack
265 resume = Resume { resumeStmt = expr, resumeThreadId = tid
266 , resumeBreakMVar = breakMVar, resumeStatMVar = statusMVar
267 , resumeBindings = bindings, resumeFinalIds = final_ids
268 , resumeApStack = apStack, resumeBreakInfo = mb_info
269 , resumeSpan = span, resumeHistory = toListBL history
270 , resumeHistoryIx = 0 }
271 hsc_env2 = pushResume hsc_env1 resume
273 modifySession (\_ -> hsc_env2)
274 return (RunBreak tid names mb_info)
275 (Complete either_hvals) ->
277 Left e -> return (RunException e)
279 hsc_env <- getSession
280 let final_ic = extendInteractiveContext (hsc_IC hsc_env) final_ids
281 final_names = map idName final_ids
282 liftIO $ Linker.extendLinkEnv (zip final_names hvals)
283 hsc_env' <- liftIO $ rttiEnvironment hsc_env{hsc_IC=final_ic}
284 modifySession (\_ -> hsc_env')
285 return (RunOk final_names)
287 traceRunStatus :: GhcMonad m =>
288 String -> [Id] -> [Id]
289 -> MVar () -> MVar Status -> Status -> BoundedList History
291 traceRunStatus expr bindings final_ids
292 breakMVar statusMVar status history = do
293 hsc_env <- getSession
295 -- when tracing, if we hit a breakpoint that is not explicitly
296 -- enabled, then we just log the event in the history and continue.
297 (Break is_exception apStack info tid) | not is_exception -> do
298 b <- liftIO $ isBreakEnabled hsc_env info
302 let history' = mkHistory hsc_env apStack info `consBL` history
303 -- probably better make history strict here, otherwise
304 -- our BoundedList will be pointless.
305 _ <- liftIO $ evaluate history'
307 withBreakAction True (hsc_dflags hsc_env)
308 breakMVar statusMVar $ do
309 liftIO $ withInterruptsSentTo tid $ do
310 putMVar breakMVar () -- awaken the stopped thread
311 takeMVar statusMVar -- and wait for the result
312 traceRunStatus expr bindings final_ids
313 breakMVar statusMVar status history'
317 handle_normally = handleRunStatus expr bindings final_ids
318 breakMVar statusMVar status history
321 isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
322 isBreakEnabled hsc_env inf =
323 case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
325 w <- getBreak (modBreaks_flags (getModBreaks hmi))
326 (breakInfo_number inf)
327 case w of Just n -> return (n /= 0); _other -> return False
332 foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
333 foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
336 setStepFlag = poke stepFlag 1
337 resetStepFlag :: IO ()
338 resetStepFlag = poke stepFlag 0
340 -- this points to the IO action that is executed when a breakpoint is hit
341 foreign import ccall "&rts_breakpoint_io_action"
342 breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
344 -- When running a computation, we redirect ^C exceptions to the running
345 -- thread. ToDo: we might want a way to continue even if the target
346 -- thread doesn't die when it receives the exception... "this thread
347 -- is not responding".
349 -- Careful here: there may be ^C exceptions flying around, so we start the new
350 -- thread blocked (forkIO inherits mask from the parent, #1048), and unblock
351 -- only while we execute the user's code. We can't afford to lose the final
352 -- putMVar, otherwise deadlock ensues. (#1583, #1922, #1946)
353 sandboxIO :: DynFlags -> MVar Status -> IO [HValue] -> IO Status
354 sandboxIO dflags statusMVar thing =
355 mask $ \restore -> -- fork starts blocked
356 let runIt = liftM Complete $ try (restore $ rethrow dflags thing)
357 in if dopt Opt_GhciSandbox dflags
358 then do tid <- forkIO $ do res <- runIt
359 putMVar statusMVar res -- empty: can't block
360 withInterruptsSentTo tid $ takeMVar statusMVar
361 else -- GLUT on OS X needs to run on the main thread. If you
362 -- try to use it from another thread then you just get a
363 -- white rectangle rendered. For this, or anything else
364 -- with such restrictions, you can turn the GHCi sandbox off
365 -- and things will be run in the main thread.
368 -- We want to turn ^C into a break when -fbreak-on-exception is on,
369 -- but it's an async exception and we only break for sync exceptions.
370 -- Idea: if we catch and re-throw it, then the re-throw will trigger
371 -- a break. Great - but we don't want to re-throw all exceptions, because
372 -- then we'll get a double break for ordinary sync exceptions (you'd have
373 -- to :continue twice, which looks strange). So if the exception is
374 -- not "Interrupted", we unset the exception flag before throwing.
376 rethrow :: DynFlags -> IO a -> IO a
377 rethrow dflags io = Exception.catch io $ \se -> do
378 -- If -fbreak-on-error, we break unconditionally,
379 -- but with care of not breaking twice
380 if dopt Opt_BreakOnError dflags &&
381 not (dopt Opt_BreakOnException dflags)
382 then poke exceptionFlag 1
383 else case fromException se of
384 -- If it is a "UserInterrupt" exception, we allow
385 -- a possible break by way of -fbreak-on-exception
386 Just UserInterrupt -> return ()
387 -- In any other case, we don't want to break
388 _ -> poke exceptionFlag 0
392 withInterruptsSentTo :: ThreadId -> IO r -> IO r
393 withInterruptsSentTo thread get_result = do
394 bracket (modifyMVar_ interruptTargetThread (return . (thread:)))
395 (\_ -> modifyMVar_ interruptTargetThread (\tl -> return $! tail tl))
398 -- This function sets up the interpreter for catching breakpoints, and
399 -- resets everything when the computation has stopped running. This
400 -- is a not-very-good way to ensure that only the interactive
401 -- evaluation should generate breakpoints.
402 withBreakAction :: (ExceptionMonad m, MonadIO m) =>
403 Bool -> DynFlags -> MVar () -> MVar Status -> m a -> m a
404 withBreakAction step dflags breakMVar statusMVar act
405 = gbracket (liftIO setBreakAction) (liftIO . resetBreakAction) (\_ -> act)
408 stablePtr <- newStablePtr onBreak
409 poke breakPointIOAction stablePtr
410 when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
411 when step $ setStepFlag
413 -- Breaking on exceptions is not enabled by default, since it
414 -- might be a bit surprising. The exception flag is turned off
415 -- as soon as it is hit, or in resetBreakAction below.
417 onBreak is_exception info apStack = do
419 putMVar statusMVar (Break is_exception apStack info tid)
422 resetBreakAction stablePtr = do
423 poke breakPointIOAction noBreakStablePtr
426 freeStablePtr stablePtr
428 noBreakStablePtr :: StablePtr (Bool -> BreakInfo -> HValue -> IO ())
429 noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
431 noBreakAction :: Bool -> BreakInfo -> HValue -> IO ()
432 noBreakAction False _ _ = putStrLn "*** Ignoring breakpoint"
433 noBreakAction True _ _ = return () -- exception: just continue
435 resume :: GhcMonad m => (SrcSpan->Bool) -> SingleStep -> m RunResult
436 resume canLogSpan step
438 hsc_env <- getSession
439 let ic = hsc_IC hsc_env
440 resume = ic_resume ic
443 [] -> ghcError (ProgramError "not stopped at a breakpoint")
445 -- unbind the temporary locals by restoring the TypeEnv from
446 -- before the breakpoint, and drop this Resume from the
447 -- InteractiveContext.
448 let resume_tmp_ids = resumeBindings r
449 ic' = ic { ic_tmp_ids = resume_tmp_ids,
451 modifySession (\_ -> hsc_env{ hsc_IC = ic' })
453 -- remove any bindings created since the breakpoint from the
454 -- linker's environment
455 let new_names = map idName (filter (`notElem` resume_tmp_ids)
457 liftIO $ Linker.deleteFromLinkEnv new_names
459 when (isStep step) $ liftIO setStepFlag
461 Resume { resumeStmt = expr, resumeThreadId = tid
462 , resumeBreakMVar = breakMVar, resumeStatMVar = statusMVar
463 , resumeBindings = bindings, resumeFinalIds = final_ids
464 , resumeApStack = apStack, resumeBreakInfo = info, resumeSpan = span
465 , resumeHistory = hist } -> do
467 withBreakAction (isStep step) (hsc_dflags hsc_env)
468 breakMVar statusMVar $ do
469 status <- liftIO $ withInterruptsSentTo tid $ do
471 -- this awakens the stopped thread...
473 -- and wait for the result
474 let prevHistoryLst = fromListBL 50 hist
476 Nothing -> prevHistoryLst
478 | not $canLogSpan span -> prevHistoryLst
479 | otherwise -> mkHistory hsc_env apStack i `consBL`
483 traceRunStatus expr bindings final_ids
484 breakMVar statusMVar status hist'
486 handleRunStatus expr bindings final_ids
487 breakMVar statusMVar status hist'
489 back :: GhcMonad m => m ([Name], Int, SrcSpan)
492 forward :: GhcMonad m => m ([Name], Int, SrcSpan)
493 forward = moveHist (subtract 1)
495 moveHist :: GhcMonad m => (Int -> Int) -> m ([Name], Int, SrcSpan)
497 hsc_env <- getSession
498 case ic_resume (hsc_IC hsc_env) of
499 [] -> ghcError (ProgramError "not stopped at a breakpoint")
501 let ix = resumeHistoryIx r
502 history = resumeHistory r
505 when (new_ix > length history) $
506 ghcError (ProgramError "no more logged breakpoints")
508 ghcError (ProgramError "already at the beginning of the history")
511 update_ic apStack mb_info = do
512 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env
514 let ic = hsc_IC hsc_env1
515 r' = r { resumeHistoryIx = new_ix }
516 ic' = ic { ic_resume = r':rs }
518 modifySession (\_ -> hsc_env1{ hsc_IC = ic' })
520 return (names, new_ix, span)
522 -- careful: we want apStack to be the AP_STACK itself, not a thunk
523 -- around it, hence the cases are carefully constructed below to
524 -- make this the case. ToDo: this is v. fragile, do something better.
527 Resume { resumeApStack = apStack,
528 resumeBreakInfo = mb_info } ->
529 update_ic apStack mb_info
530 else case history !! (new_ix - 1) of
531 History apStack info _ ->
532 update_ic apStack (Just info)
534 -- -----------------------------------------------------------------------------
535 -- After stopping at a breakpoint, add free variables to the environment
536 result_fs :: FastString
537 result_fs = fsLit "_result"
539 bindLocalsAtBreakpoint
543 -> IO (HscEnv, [Name], SrcSpan)
545 -- Nothing case: we stopped when an exception was raised, not at a
546 -- breakpoint. We have no location information or local variables to
547 -- bind, all we can do is bind a local variable to the exception
549 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
550 let exn_fs = fsLit "_exception"
551 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
553 e_name = mkInternalName (getUnique e_fs) (mkTyVarOccFS e_fs) span
554 e_tyvar = mkRuntimeUnkTyVar e_name liftedTypeKind
555 exn_id = Id.mkVanillaGlobal exn_name (mkTyVarTy e_tyvar)
557 ictxt0 = hsc_IC hsc_env
558 ictxt1 = extendInteractiveContext ictxt0 [exn_id]
560 span = mkGeneralSrcSpan (fsLit "<exception thrown>")
562 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
563 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
565 -- Just case: we stopped at a breakpoint, we have information about the location
566 -- of the breakpoint and the free variables of the expression.
567 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
570 mod_name = moduleName (breakInfo_module info)
571 hmi = expectJust "bindLocalsAtBreakpoint" $
572 lookupUFM (hsc_HPT hsc_env) mod_name
573 breaks = getModBreaks hmi
574 index = breakInfo_number info
575 vars = breakInfo_vars info
576 result_ty = breakInfo_resty info
577 occs = modBreaks_vars breaks ! index
578 span = modBreaks_locs breaks ! index
580 -- Filter out any unboxed ids;
581 -- we can't bind these at the prompt
582 pointers = filter (\(id,_) -> isPointer id) vars
583 isPointer id | PtrRep <- idPrimRep id = True
586 (ids, offsets) = unzip pointers
588 free_tvs = foldr (unionVarSet . tyVarsOfType . idType)
589 (tyVarsOfType result_ty) ids
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 us <- mkSplitUniqSupply 'I'
602 let (us1, us2) = splitUniqSupply us
603 tv_subst = newTyVars us1 free_tvs
604 new_ids = zipWith3 (mkNewId tv_subst) occs filtered_ids (uniqsFromSupply us2)
605 names = map idName new_ids
607 -- make an Id for _result. We use the Unique of the FastString "_result";
608 -- we don't care about uniqueness here, because there will only be one
609 -- _result in scope at any time.
610 let result_name = mkInternalName (getUnique result_fs)
611 (mkVarOccFS result_fs) span
612 result_id = Id.mkVanillaGlobal result_name (substTy tv_subst result_ty)
614 -- for each Id we're about to bind in the local envt:
615 -- - tidy the type variables
616 -- - globalise the Id (Ids are supposed to be Global, apparently).
618 let result_ok = isPointer result_id
619 && not (isUnboxedTupleType (idType result_id))
621 all_ids | result_ok = result_id : new_ids
622 | otherwise = new_ids
623 id_tys = map idType all_ids
624 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
625 final_ids = zipWith setIdType all_ids tidy_tys
626 ictxt0 = hsc_IC hsc_env
627 ictxt1 = extendInteractiveContext ictxt0 final_ids
629 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
630 when result_ok $ Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
631 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
632 return (hsc_env1, if result_ok then result_name:names else names, span)
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.
638 mkNewId :: TvSubst -> OccName -> Id -> Unique -> Id
639 mkNewId tv_subst occ id uniq
640 = Id.mkVanillaGlobalWithInfo name ty (idInfo id)
642 loc = nameSrcSpan (idName id)
643 name = mkInternalName uniq occ loc
644 ty = substTy tv_subst (idType id)
646 newTyVars :: UniqSupply -> TcTyVarSet -> TvSubst
647 -- Similarly, clone the type variables mentioned in the types
648 -- we have here, *and* make them all RuntimeUnk tyars
650 = mkTopTvSubst [ (tv, mkTyVarTy (mkRuntimeUnkTyVar name (tyVarKind tv)))
651 | (tv, uniq) <- varSetElems tvs `zip` uniqsFromSupply us
652 , let name = setNameUnique (tyVarName tv) uniq ]
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 -> [ImportDecl RdrName] -- ^ these import declarations
782 setContext toplev_mods import_decls = do
783 hsc_env <- getSession
784 let old_ic = hsc_IC hsc_env
785 hpt = hsc_HPT hsc_env
786 imprt_decls = map noLoc import_decls
789 if null imprt_decls then return emptyGlobalRdrEnv else do
790 let this_mod | null toplev_mods = pRELUDE
791 | otherwise = head toplev_mods
792 liftIO $ hscRnImportDecls hsc_env this_mod imprt_decls
794 toplev_envs <- liftIO $ mapM (mkTopLevEnv hpt) toplev_mods
796 let all_env = foldr plusGlobalRdrEnv import_env toplev_envs
797 modifySession $ \_ ->
798 hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
799 ic_imports = import_decls,
800 ic_rn_gbl_env = all_env }}
802 availsToGlobalRdrEnv :: ModuleName -> [AvailInfo] -> GlobalRdrEnv
803 availsToGlobalRdrEnv mod_name avails
804 = mkGlobalRdrEnv (gresFromAvails imp_prov avails)
806 -- We're building a GlobalRdrEnv as if the user imported
807 -- all the specified modules into the global interactive module
808 imp_prov = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
809 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
811 is_dloc = srcLocSpan interactiveSrcLoc }
813 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
815 = case lookupUFM hpt (moduleName modl) of
816 Nothing -> ghcError (ProgramError ("mkTopLevEnv: not a home module " ++
817 showSDoc (ppr modl)))
819 case mi_globals (hm_iface details) of
821 ghcError (ProgramError ("mkTopLevEnv: not interpreted "
822 ++ showSDoc (ppr modl)))
823 Just env -> return env
825 -- | Get the interactive evaluation context, consisting of a pair of the
826 -- set of modules from which we take the full top-level scope, and the set
827 -- of modules from which we take just the exports respectively.
828 getContext :: GhcMonad m => m ([Module],[ImportDecl RdrName])
829 getContext = withSession $ \HscEnv{ hsc_IC=ic } ->
830 return (ic_toplev_scope ic, ic_imports ic)
832 -- | Returns @True@ if the specified module is interpreted, and hence has
833 -- its full top-level scope available.
834 moduleIsInterpreted :: GhcMonad m => Module -> m Bool
835 moduleIsInterpreted modl = withSession $ \h ->
836 if modulePackageId modl /= thisPackage (hsc_dflags h)
838 else case lookupUFM (hsc_HPT h) (moduleName modl) of
839 Just details -> return (isJust (mi_globals (hm_iface details)))
840 _not_a_home_module -> return False
842 -- | Looks up an identifier in the current interactive context (for :info)
843 -- Filter the instances by the ones whose tycons (or clases resp)
844 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
845 -- The exact choice of which ones to show, and which to hide, is a judgement call.
847 getInfo :: GhcMonad m => Name -> m (Maybe (TyThing,Fixity,[Instance]))
849 = withSession $ \hsc_env ->
850 do mb_stuff <- liftIO $ hscTcRnGetInfo hsc_env name
852 Nothing -> return Nothing
853 Just (thing, fixity, ispecs) -> do
854 let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
855 return (Just (thing, fixity, filter (plausible rdr_env) ispecs))
857 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
858 = all ok $ nameSetToList $ orphNamesOfType $ idType $ instanceDFunId ispec
859 where -- A name is ok if it's in the rdr_env,
860 -- whether qualified or not
861 ok n | n == name = True -- The one we looked for in the first place!
862 | isBuiltInSyntax n = True
863 | isExternalName n = any ((== n) . gre_name)
864 (lookupGRE_Name rdr_env n)
867 -- | Returns all names in scope in the current interactive context
868 getNamesInScope :: GhcMonad m => m [Name]
869 getNamesInScope = withSession $ \hsc_env -> do
870 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
872 getRdrNamesInScope :: GhcMonad m => m [RdrName]
873 getRdrNamesInScope = withSession $ \hsc_env -> do
876 gbl_rdrenv = ic_rn_gbl_env ic
878 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
879 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
881 return (gbl_names ++ lcl_names)
884 -- ToDo: move to RdrName
885 greToRdrNames :: GlobalRdrElt -> [RdrName]
886 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
889 Imported specs -> concat (map do_spec (map is_decl specs))
891 occ = nameOccName name
894 | is_qual decl_spec = [qual]
895 | otherwise = [unqual,qual]
896 where qual = Qual (is_as decl_spec) occ
898 -- | Parses a string as an identifier, and returns the list of 'Name's that
899 -- the identifier can refer to in the current interactive context.
900 parseName :: GhcMonad m => String -> m [Name]
901 parseName str = withSession $ \hsc_env -> do
902 (L _ rdr_name) <- liftIO $ hscParseIdentifier hsc_env str
903 liftIO $ hscTcRnLookupRdrName hsc_env rdr_name
905 -- -----------------------------------------------------------------------------
906 -- Getting the type of an expression
908 -- | Get the type of an expression
909 exprType :: GhcMonad m => String -> m Type
910 exprType expr = withSession $ \hsc_env -> do
911 ty <- liftIO $ hscTcExpr hsc_env expr
912 return $ tidyType emptyTidyEnv ty
914 -- -----------------------------------------------------------------------------
915 -- Getting the kind of a type
917 -- | Get the kind of a type
918 typeKind :: GhcMonad m => String -> m Kind
919 typeKind str = withSession $ \hsc_env -> do
920 liftIO $ hscKcType hsc_env str
922 -----------------------------------------------------------------------------
923 -- cmCompileExpr: compile an expression and deliver an HValue
925 compileExpr :: GhcMonad m => String -> m HValue
926 compileExpr expr = withSession $ \hsc_env -> do
927 Just (ids, hval) <- liftIO $ hscStmt hsc_env ("let __cmCompileExpr = "++expr)
929 hvals <- liftIO (unsafeCoerce# hval :: IO [HValue])
932 ([_],[hv]) -> return hv
933 _ -> panic "compileExpr"
935 -- -----------------------------------------------------------------------------
936 -- Compile an expression into a dynamic
938 dynCompileExpr :: GhcMonad m => String -> m Dynamic
939 dynCompileExpr expr = do
940 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
941 Just (ids, hvals) <- withSession $ \hsc_env ->
942 liftIO $ hscStmt hsc_env stmt
943 vals <- liftIO (unsafeCoerce# hvals :: IO [Dynamic])
945 (_:[], v:[]) -> return v
946 _ -> panic "dynCompileExpr"
948 -----------------------------------------------------------------------------
949 -- show a module and it's source/object filenames
951 showModule :: GhcMonad m => ModSummary -> m String
952 showModule mod_summary =
953 withSession $ \hsc_env -> do
954 interpreted <- isModuleInterpreted mod_summary
955 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
957 isModuleInterpreted :: GhcMonad m => ModSummary -> m Bool
958 isModuleInterpreted mod_summary = withSession $ \hsc_env ->
959 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
960 Nothing -> panic "missing linkable"
961 Just mod_info -> return (not obj_linkable)
963 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
965 ----------------------------------------------------------------------------
968 obtainTermFromVal :: HscEnv -> Int -> Bool -> Type -> a -> IO Term
969 obtainTermFromVal hsc_env bound force ty x =
970 cvObtainTerm hsc_env bound force ty (unsafeCoerce# x)
972 obtainTermFromId :: HscEnv -> Int -> Bool -> Id -> IO Term
973 obtainTermFromId hsc_env bound force id = do
974 hv <- Linker.getHValue hsc_env (varName id)
975 cvObtainTerm hsc_env bound force (idType id) hv
977 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
978 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
979 reconstructType hsc_env bound id = do
980 hv <- Linker.getHValue hsc_env (varName id)
981 cvReconstructType hsc_env bound (idType id) hv
983 mkRuntimeUnkTyVar :: Name -> Kind -> TyVar
984 mkRuntimeUnkTyVar name kind = mkTcTyVar name kind RuntimeUnk