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,
33 skolemiseSubst, skolemiseTy
39 #include "HsVersions.h"
41 import HscMain hiding (compileExpr)
42 import HsSyn (ImportDecl)
45 import TcRnMonad (initTc)
46 import RnNames (gresFromAvails, rnImports)
49 import TcType hiding( typeKind )
52 import Name hiding ( varName )
55 import PrelNames (pRELUDE)
71 import RtClosureInspect
77 import System.Directory
79 import Data.List (find, partition)
81 import Foreign hiding (unsafePerformIO)
86 import Control.Concurrent
87 import Data.List (sortBy)
88 -- import Foreign.StablePtr
90 import System.IO.Unsafe
92 -- -----------------------------------------------------------------------------
93 -- running a statement interactively
96 = RunOk [Name] -- ^ names bound by this evaluation
97 | RunFailed -- ^ statement failed compilation
98 | RunException SomeException -- ^ statement raised an exception
99 | RunBreak ThreadId [Name] (Maybe BreakInfo)
102 = Break Bool HValue BreakInfo ThreadId
103 -- ^ the computation hit a breakpoint (Bool <=> was an exception)
104 | Complete (Either SomeException [HValue])
105 -- ^ the computation completed with either an exception or a value
109 resumeStmt :: String, -- the original statement
110 resumeThreadId :: ThreadId, -- thread running the computation
111 resumeBreakMVar :: MVar (),
112 resumeStatMVar :: MVar Status,
113 resumeBindings :: ([Id], TyVarSet),
114 resumeFinalIds :: [Id], -- [Id] to bind on completion
115 resumeApStack :: HValue, -- The object from which we can get
116 -- value of the free variables.
117 resumeBreakInfo :: Maybe BreakInfo,
118 -- the breakpoint we stopped at
119 -- (Nothing <=> exception)
120 resumeSpan :: SrcSpan, -- just a cache, otherwise it's a pain
121 -- to fetch the ModDetails & ModBreaks
123 resumeHistory :: [History],
124 resumeHistoryIx :: Int -- 0 <==> at the top of the history
127 getResumeContext :: GhcMonad m => m [Resume]
128 getResumeContext = withSession (return . ic_resume . hsc_IC)
135 isStep :: SingleStep -> Bool
136 isStep RunToCompletion = False
141 historyApStack :: HValue,
142 historyBreakInfo :: BreakInfo,
143 historyEnclosingDecl :: Id
144 -- ^^ A cache of the enclosing top level declaration, for convenience
147 mkHistory :: HscEnv -> HValue -> BreakInfo -> History
148 mkHistory hsc_env hval bi = let
149 h = History hval bi decl
150 decl = findEnclosingDecl hsc_env (getHistoryModule h)
151 (getHistorySpan hsc_env h)
154 getHistoryModule :: History -> Module
155 getHistoryModule = breakInfo_module . historyBreakInfo
157 getHistorySpan :: HscEnv -> History -> SrcSpan
158 getHistorySpan hsc_env hist =
159 let inf = historyBreakInfo hist
160 num = breakInfo_number inf
161 in case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
162 Just hmi -> modBreaks_locs (getModBreaks hmi) ! num
163 _ -> panic "getHistorySpan"
165 getModBreaks :: HomeModInfo -> ModBreaks
167 | Just linkable <- hm_linkable hmi,
168 [BCOs _ modBreaks] <- linkableUnlinked linkable
171 = emptyModBreaks -- probably object code
173 {- | Finds the enclosing top level function name -}
174 -- ToDo: a better way to do this would be to keep hold of the decl_path computed
175 -- by the coverage pass, which gives the list of lexically-enclosing bindings
177 findEnclosingDecl :: HscEnv -> Module -> SrcSpan -> Id
178 findEnclosingDecl hsc_env mod span =
179 case lookupUFM (hsc_HPT hsc_env) (moduleName mod) of
180 Nothing -> panic "findEnclosingDecl"
182 globals = typeEnvIds (md_types (hm_details hmi))
184 find (\id -> let n = idName id in
185 nameSrcSpan n < span && isExternalName n)
186 (reverse$ sortBy (compare `on` (nameSrcSpan.idName))
190 -- | Run a statement in the current interactive context. Statement
191 -- may bind multple values.
192 runStmt :: GhcMonad m => String -> SingleStep -> m RunResult
195 hsc_env <- getSession
197 breakMVar <- liftIO $ newEmptyMVar -- wait on this when we hit a breakpoint
198 statusMVar <- liftIO $ newEmptyMVar -- wait on this when a computation is running
200 -- Turn off -fwarn-unused-bindings when running a statement, to hide
201 -- warnings about the implicit bindings we introduce.
202 let dflags' = dopt_unset (hsc_dflags hsc_env) Opt_WarnUnusedBinds
203 hsc_env' = hsc_env{ hsc_dflags = dflags' }
205 r <- hscStmt hsc_env' expr
208 Nothing -> return RunFailed -- empty statement / comment
210 Just (ids, hval) -> do
211 -- XXX: This is the only place we can print warnings before the
212 -- result. Is this really the right thing to do? It's fine for
213 -- GHCi, but what's correct for other GHC API clients? We could
214 -- introduce a callback argument.
216 liftIO $ printBagOfWarnings dflags' warns
221 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
222 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
223 liftIO $ sandboxIO dflags' statusMVar thing_to_run
225 let ic = hsc_IC hsc_env
226 bindings = (ic_tmp_ids ic, ic_tyvars ic)
230 traceRunStatus expr bindings ids
231 breakMVar statusMVar status emptyHistory
233 handleRunStatus expr bindings ids
234 breakMVar statusMVar status emptyHistory
236 withVirtualCWD :: GhcMonad m => m a -> m a
237 withVirtualCWD m = do
238 hsc_env <- getSession
239 let ic = hsc_IC hsc_env
242 dir <- liftIO $ getCurrentDirectory
244 Just dir -> liftIO $ setCurrentDirectory dir
248 reset_cwd orig_dir = do
249 virt_dir <- liftIO $ getCurrentDirectory
250 hsc_env <- getSession
251 let old_IC = hsc_IC hsc_env
252 setSession hsc_env{ hsc_IC = old_IC{ ic_cwd = Just virt_dir } }
253 liftIO $ setCurrentDirectory orig_dir
255 gbracket set_cwd reset_cwd $ \_ -> m
257 parseImportDecl :: GhcMonad m => String -> m (ImportDecl RdrName)
258 parseImportDecl expr = withSession $ \hsc_env -> hscImport hsc_env expr
260 emptyHistory :: BoundedList History
261 emptyHistory = nilBL 50 -- keep a log of length 50
263 handleRunStatus :: GhcMonad m =>
264 String-> ([Id], TyVarSet) -> [Id]
265 -> MVar () -> MVar Status -> Status -> BoundedList History
267 handleRunStatus expr bindings final_ids breakMVar statusMVar status
270 -- did we hit a breakpoint or did we complete?
271 (Break is_exception apStack info tid) -> do
272 hsc_env <- getSession
273 let mb_info | is_exception = Nothing
274 | otherwise = Just info
275 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env apStack
278 resume = Resume expr tid breakMVar statusMVar
279 bindings final_ids apStack mb_info span
281 hsc_env2 = pushResume hsc_env1 resume
283 modifySession (\_ -> hsc_env2)
284 return (RunBreak tid names mb_info)
285 (Complete either_hvals) ->
287 Left e -> return (RunException e)
289 hsc_env <- getSession
290 let final_ic = extendInteractiveContext (hsc_IC hsc_env)
291 final_ids emptyVarSet
292 -- the bound Ids never have any free TyVars
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], TyVarSet) -> [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, resume_tyvars) = resumeBindings r
461 ic' = ic { ic_tmp_ids = resume_tmp_ids,
462 ic_tyvars = resume_tyvars,
464 modifySession (\_ -> hsc_env{ hsc_IC = ic' })
466 -- remove any bindings created since the breakpoint from the
467 -- linker's environment
468 let new_names = map idName (filter (`notElem` resume_tmp_ids)
470 liftIO $ Linker.deleteFromLinkEnv new_names
472 when (isStep step) $ liftIO setStepFlag
474 Resume expr tid breakMVar statusMVar bindings
475 final_ids apStack info span hist _ -> do
477 withBreakAction (isStep step) (hsc_dflags hsc_env)
478 breakMVar statusMVar $ do
479 status <- liftIO $ withInterruptsSentTo tid $ do
481 -- this awakens the stopped thread...
483 -- and wait for the result
484 let prevHistoryLst = fromListBL 50 hist
486 Nothing -> prevHistoryLst
488 | not $canLogSpan span -> prevHistoryLst
489 | otherwise -> mkHistory hsc_env apStack i `consBL`
493 traceRunStatus expr bindings final_ids
494 breakMVar statusMVar status hist'
496 handleRunStatus expr bindings final_ids
497 breakMVar statusMVar status hist'
499 back :: GhcMonad m => m ([Name], Int, SrcSpan)
502 forward :: GhcMonad m => m ([Name], Int, SrcSpan)
503 forward = moveHist (subtract 1)
505 moveHist :: GhcMonad m => (Int -> Int) -> m ([Name], Int, SrcSpan)
507 hsc_env <- getSession
508 case ic_resume (hsc_IC hsc_env) of
509 [] -> ghcError (ProgramError "not stopped at a breakpoint")
511 let ix = resumeHistoryIx r
512 history = resumeHistory r
515 when (new_ix > length history) $
516 ghcError (ProgramError "no more logged breakpoints")
518 ghcError (ProgramError "already at the beginning of the history")
521 update_ic apStack mb_info = do
522 (hsc_env1, names, span) <- liftIO $ bindLocalsAtBreakpoint hsc_env
524 let ic = hsc_IC hsc_env1
525 r' = r { resumeHistoryIx = new_ix }
526 ic' = ic { ic_resume = r':rs }
528 modifySession (\_ -> hsc_env1{ hsc_IC = ic' })
530 return (names, new_ix, span)
532 -- careful: we want apStack to be the AP_STACK itself, not a thunk
533 -- around it, hence the cases are carefully constructed below to
534 -- make this the case. ToDo: this is v. fragile, do something better.
537 Resume { resumeApStack = apStack,
538 resumeBreakInfo = mb_info } ->
539 update_ic apStack mb_info
540 else case history !! (new_ix - 1) of
541 History apStack info _ ->
542 update_ic apStack (Just info)
544 -- -----------------------------------------------------------------------------
545 -- After stopping at a breakpoint, add free variables to the environment
546 result_fs :: FastString
547 result_fs = fsLit "_result"
549 bindLocalsAtBreakpoint
553 -> IO (HscEnv, [Name], SrcSpan)
555 -- Nothing case: we stopped when an exception was raised, not at a
556 -- breakpoint. We have no location information or local variables to
557 -- bind, all we can do is bind a local variable to the exception
559 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
560 let exn_fs = fsLit "_exception"
561 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
563 e_name = mkInternalName (getUnique e_fs) (mkTyVarOccFS e_fs) span
564 e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
565 exn_id = Id.mkVanillaGlobal exn_name (mkTyVarTy e_tyvar)
566 new_tyvars = unitVarSet e_tyvar
568 ictxt0 = hsc_IC hsc_env
569 ictxt1 = extendInteractiveContext ictxt0 [exn_id] new_tyvars
571 span = mkGeneralSrcSpan (fsLit "<exception thrown>")
573 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
574 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
576 -- Just case: we stopped at a breakpoint, we have information about the location
577 -- of the breakpoint and the free variables of the expression.
578 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
581 mod_name = moduleName (breakInfo_module info)
582 hmi = expectJust "bindLocalsAtBreakpoint" $
583 lookupUFM (hsc_HPT hsc_env) mod_name
584 breaks = getModBreaks hmi
585 index = breakInfo_number info
586 vars = breakInfo_vars info
587 result_ty = breakInfo_resty info
588 occs = modBreaks_vars breaks ! index
589 span = modBreaks_locs breaks ! index
591 -- filter out any unboxed ids; we can't bind these at the prompt
592 let pointers = filter (\(id,_) -> isPointer id) vars
593 isPointer id | PtrRep <- idPrimRep id = True
596 let (ids, offsets) = unzip pointers
598 -- It might be that getIdValFromApStack fails, because the AP_STACK
599 -- has been accidentally evaluated, or something else has gone wrong.
600 -- So that we don't fall over in a heap when this happens, just don't
601 -- bind any free variables instead, and we emit a warning.
602 mb_hValues <- mapM (getIdValFromApStack apStack) (map fromIntegral offsets)
603 let filtered_ids = [ id | (id, Just _hv) <- zip ids mb_hValues ]
604 when (any isNothing mb_hValues) $
605 debugTraceMsg (hsc_dflags hsc_env) 1 $
606 text "Warning: _result has been evaluated, some bindings have been lost"
608 new_ids <- zipWithM mkNewId occs filtered_ids
609 let names = map idName new_ids
611 -- make an Id for _result. We use the Unique of the FastString "_result";
612 -- we don't care about uniqueness here, because there will only be one
613 -- _result in scope at any time.
614 let result_name = mkInternalName (getUnique result_fs)
615 (mkVarOccFS result_fs) span
616 result_id = Id.mkVanillaGlobal result_name result_ty
618 -- for each Id we're about to bind in the local envt:
619 -- - skolemise the type variables in its type, so they can't
620 -- be randomly unified with other types. These type variables
621 -- can only be resolved by type reconstruction in RtClosureInspect
622 -- - tidy the type variables
623 -- - globalise the Id (Ids are supposed to be Global, apparently).
625 let result_ok = isPointer result_id
626 && not (isUnboxedTupleType (idType result_id))
628 all_ids | result_ok = result_id : new_ids
629 | otherwise = new_ids
630 (id_tys, tyvarss) = mapAndUnzip (skolemiseTy.idType) all_ids
631 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
632 new_tyvars = unionVarSets tyvarss
633 final_ids = zipWith setIdType all_ids tidy_tys
634 ictxt0 = hsc_IC hsc_env
635 ictxt1 = extendInteractiveContext ictxt0 final_ids new_tyvars
637 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
638 when result_ok $ Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
639 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
640 return (hsc_env1, if result_ok then result_name:names else names, span)
642 mkNewId :: OccName -> Id -> IO Id
644 us <- mkSplitUniqSupply 'I'
645 -- we need a fresh Unique for each Id we bind, because the linker
646 -- state is single-threaded and otherwise we'd spam old bindings
647 -- whenever we stop at a breakpoint. The InteractveContext is properly
648 -- saved/restored, but not the linker state. See #1743, test break026.
650 uniq = uniqFromSupply us
651 loc = nameSrcSpan (idName id)
652 name = mkInternalName uniq occ loc
654 new_id = Id.mkVanillaGlobalWithInfo name ty (idInfo id)
657 rttiEnvironment :: HscEnv -> IO HscEnv
658 rttiEnvironment hsc_env@HscEnv{hsc_IC=ic} = do
659 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
660 incompletelyTypedIds =
663 , (occNameFS.nameOccName.idName) id /= result_fs]
664 hsc_env' <- foldM improveTypes hsc_env (map idName incompletelyTypedIds)
667 noSkolems = null . filter isSkolemTyVar . varSetElems . tyVarsOfType . idType
668 improveTypes hsc_env@HscEnv{hsc_IC=ic} name = do
669 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
670 Just id = find (\i -> idName i == name) tmp_ids
674 mb_new_ty <- reconstructType hsc_env 10 id
675 let old_ty = idType id
677 Nothing -> return hsc_env
679 mb_subst <- improveRTTIType hsc_env old_ty new_ty
682 WARN(True, text (":print failed to calculate the "
683 ++ "improvement for a type")) hsc_env
685 when (dopt Opt_D_dump_rtti (hsc_dflags hsc_env)) $
686 printForUser stderr alwaysQualify $
687 fsep [text "RTTI Improvement for", ppr id, equals, ppr subst]
689 let (subst', skols) = skolemiseSubst subst
690 ic' = extendInteractiveContext
691 (substInteractiveContext ic subst') [] skols
692 return hsc_env{hsc_IC=ic'}
694 skolemiseSubst :: TvSubst -> (TvSubst, TyVarSet)
695 skolemiseSubst subst = let
696 varenv = getTvSubstEnv subst
697 all_together = mapVarEnv skolemiseTy varenv
698 (varenv', skol_vars) = ( mapVarEnv fst all_together
699 , map snd (varEnvElts all_together))
700 in (subst `setTvSubstEnv` varenv', unionVarSets skol_vars)
703 skolemiseTy :: Type -> (Type, TyVarSet)
704 skolemiseTy ty = (substTy subst ty, mkVarSet new_tyvars)
705 where env = mkVarEnv (zip tyvars new_tyvar_tys)
706 subst = mkTvSubst emptyInScopeSet env
707 tyvars = varSetElems (tyVarsOfType ty)
708 new_tyvars = map skolemiseTyVar tyvars
709 new_tyvar_tys = map mkTyVarTy new_tyvars
711 skolemiseTyVar :: TyVar -> TyVar
712 skolemiseTyVar tyvar = mkTcTyVar (tyVarName tyvar) (tyVarKind tyvar)
713 (SkolemTv RuntimeUnkSkol)
715 getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
716 getIdValFromApStack apStack (I# stackDepth) = do
717 case getApStackVal# apStack (stackDepth +# 1#) of
718 -- The +1 is magic! I don't know where it comes
719 -- from, but this makes things line up. --SDM
722 0# -> return Nothing -- AP_STACK not found
723 _ -> return (Just (unsafeCoerce# result))
725 pushResume :: HscEnv -> Resume -> HscEnv
726 pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
728 ictxt0 = hsc_IC hsc_env
729 ictxt1 = ictxt0 { ic_resume = resume : ic_resume ictxt0 }
731 -- -----------------------------------------------------------------------------
732 -- Abandoning a resume context
734 abandon :: GhcMonad m => m Bool
736 hsc_env <- getSession
737 let ic = hsc_IC hsc_env
738 resume = ic_resume ic
742 modifySession $ \_ -> hsc_env{ hsc_IC = ic { ic_resume = rs } }
746 abandonAll :: GhcMonad m => m Bool
748 hsc_env <- getSession
749 let ic = hsc_IC hsc_env
750 resume = ic_resume ic
754 modifySession $ \_ -> hsc_env{ hsc_IC = ic { ic_resume = [] } }
755 liftIO $ mapM_ abandon_ rs
758 -- when abandoning a computation we have to
759 -- (a) kill the thread with an async exception, so that the
760 -- computation itself is stopped, and
761 -- (b) fill in the MVar. This step is necessary because any
762 -- thunks that were under evaluation will now be updated
763 -- with the partial computation, which still ends in takeMVar,
764 -- so any attempt to evaluate one of these thunks will block
765 -- unless we fill in the MVar.
766 -- See test break010.
767 abandon_ :: Resume -> IO ()
769 killThread (resumeThreadId r)
770 putMVar (resumeBreakMVar r) ()
772 -- -----------------------------------------------------------------------------
773 -- Bounded list, optimised for repeated cons
775 data BoundedList a = BL
776 {-# UNPACK #-} !Int -- length
777 {-# UNPACK #-} !Int -- bound
779 [a] -- right, list is (left ++ reverse right)
781 nilBL :: Int -> BoundedList a
782 nilBL bound = BL 0 bound [] []
784 consBL :: a -> BoundedList a -> BoundedList a
785 consBL a (BL len bound left right)
786 | len < bound = BL (len+1) bound (a:left) right
787 | null right = BL len bound [a] $! tail (reverse left)
788 | otherwise = BL len bound (a:left) $! tail right
790 toListBL :: BoundedList a -> [a]
791 toListBL (BL _ _ left right) = left ++ reverse right
793 fromListBL :: Int -> [a] -> BoundedList a
794 fromListBL bound l = BL (length l) bound l []
796 -- lenBL (BL len _ _ _) = len
798 -- -----------------------------------------------------------------------------
799 -- | Set the interactive evaluation context.
801 -- Setting the context doesn't throw away any bindings; the bindings
802 -- we've built up in the InteractiveContext simply move to the new
803 -- module. They always shadow anything in scope in the current context.
804 setContext :: GhcMonad m =>
805 [Module] -- ^ entire top level scope of these modules
806 -> [(Module, Maybe (ImportDecl RdrName))] -- ^ exports of these modules
808 setContext toplev_mods other_mods = do
809 hsc_env <- getSession
810 let old_ic = hsc_IC hsc_env
811 hpt = hsc_HPT hsc_env
812 (decls,mods) = partition (isJust . snd) other_mods -- time for tracing
813 export_mods = map fst mods
814 imprt_decls = map noLoc (catMaybes (map snd decls))
816 export_env <- liftIO $ mkExportEnv hsc_env export_mods
818 if null imprt_decls then return emptyGlobalRdrEnv else do
819 let imports = rnImports imprt_decls
820 this_mod = if null toplev_mods then pRELUDE else head toplev_mods
822 ioMsgMaybe $ liftIO $ initTc hsc_env HsSrcFile False this_mod imports
824 toplev_envs <- liftIO $ mapM (mkTopLevEnv hpt) toplev_mods
825 let all_env = foldr plusGlobalRdrEnv (plusGlobalRdrEnv export_env import_env) toplev_envs
826 modifySession $ \_ ->
827 hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
828 ic_exports = other_mods,
829 ic_rn_gbl_env = all_env }}
831 -- Make a GlobalRdrEnv based on the exports of the modules only.
832 mkExportEnv :: HscEnv -> [Module] -> IO GlobalRdrEnv
833 mkExportEnv hsc_env mods
834 = do { stuff <- mapM (getModuleExports hsc_env) mods
835 ; let (_msgs, mb_name_sets) = unzip stuff
836 envs = [ availsToGlobalRdrEnv (moduleName mod) avails
837 | (Just avails, mod) <- zip mb_name_sets mods ]
838 ; return $! foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs }
840 availsToGlobalRdrEnv :: ModuleName -> [AvailInfo] -> GlobalRdrEnv
841 availsToGlobalRdrEnv mod_name avails
842 = mkGlobalRdrEnv (gresFromAvails imp_prov avails)
844 -- We're building a GlobalRdrEnv as if the user imported
845 -- all the specified modules into the global interactive module
846 imp_prov = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
847 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
849 is_dloc = srcLocSpan interactiveSrcLoc }
851 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
853 = case lookupUFM hpt (moduleName modl) of
854 Nothing -> ghcError (ProgramError ("mkTopLevEnv: not a home module " ++
855 showSDoc (ppr modl)))
857 case mi_globals (hm_iface details) of
859 ghcError (ProgramError ("mkTopLevEnv: not interpreted "
860 ++ showSDoc (ppr modl)))
861 Just env -> return env
863 -- | Get the interactive evaluation context, consisting of a pair of the
864 -- set of modules from which we take the full top-level scope, and the set
865 -- of modules from which we take just the exports respectively.
866 getContext :: GhcMonad m => m ([Module],[(Module, Maybe (ImportDecl RdrName))])
867 getContext = withSession $ \HscEnv{ hsc_IC=ic } ->
868 return (ic_toplev_scope ic, ic_exports ic)
870 -- | Returns @True@ if the specified module is interpreted, and hence has
871 -- its full top-level scope available.
872 moduleIsInterpreted :: GhcMonad m => Module -> m Bool
873 moduleIsInterpreted modl = withSession $ \h ->
874 if modulePackageId modl /= thisPackage (hsc_dflags h)
876 else case lookupUFM (hsc_HPT h) (moduleName modl) of
877 Just details -> return (isJust (mi_globals (hm_iface details)))
878 _not_a_home_module -> return False
880 -- | Looks up an identifier in the current interactive context (for :info)
881 -- Filter the instances by the ones whose tycons (or clases resp)
882 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
883 -- The exact choice of which ones to show, and which to hide, is a judgement call.
885 getInfo :: GhcMonad m => Name -> m (Maybe (TyThing,Fixity,[Instance]))
887 = withSession $ \hsc_env ->
888 do mb_stuff <- ioMsg $ tcRnGetInfo hsc_env name
890 Nothing -> return Nothing
891 Just (thing, fixity, ispecs) -> do
892 let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
893 return (Just (thing, fixity, filter (plausible rdr_env) ispecs))
895 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
896 = all ok $ nameSetToList $ tyClsNamesOfType $ idType $ instanceDFunId ispec
897 where -- A name is ok if it's in the rdr_env,
898 -- whether qualified or not
899 ok n | n == name = True -- The one we looked for in the first place!
900 | isBuiltInSyntax n = True
901 | isExternalName n = any ((== n) . gre_name)
902 (lookupGRE_Name rdr_env n)
905 -- | Returns all names in scope in the current interactive context
906 getNamesInScope :: GhcMonad m => m [Name]
907 getNamesInScope = withSession $ \hsc_env -> do
908 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
910 getRdrNamesInScope :: GhcMonad m => m [RdrName]
911 getRdrNamesInScope = withSession $ \hsc_env -> do
914 gbl_rdrenv = ic_rn_gbl_env ic
916 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
917 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
919 return (gbl_names ++ lcl_names)
922 -- ToDo: move to RdrName
923 greToRdrNames :: GlobalRdrElt -> [RdrName]
924 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
927 Imported specs -> concat (map do_spec (map is_decl specs))
929 occ = nameOccName name
932 | is_qual decl_spec = [qual]
933 | otherwise = [unqual,qual]
934 where qual = Qual (is_as decl_spec) occ
936 -- | Parses a string as an identifier, and returns the list of 'Name's that
937 -- the identifier can refer to in the current interactive context.
938 parseName :: GhcMonad m => String -> m [Name]
939 parseName str = withSession $ \hsc_env -> do
940 (L _ rdr_name) <- hscParseIdentifier (hsc_dflags hsc_env) str
941 ioMsgMaybe $ tcRnLookupRdrName hsc_env rdr_name
943 -- -----------------------------------------------------------------------------
944 -- Getting the type of an expression
946 -- | Get the type of an expression
947 exprType :: GhcMonad m => String -> m Type
948 exprType expr = withSession $ \hsc_env -> do
949 ty <- hscTcExpr hsc_env expr
950 return $ tidyType emptyTidyEnv ty
952 -- -----------------------------------------------------------------------------
953 -- Getting the kind of a type
955 -- | Get the kind of a type
956 typeKind :: GhcMonad m => String -> m Kind
957 typeKind str = withSession $ \hsc_env -> do
958 hscKcType hsc_env str
960 -----------------------------------------------------------------------------
961 -- cmCompileExpr: compile an expression and deliver an HValue
963 compileExpr :: GhcMonad m => String -> m HValue
964 compileExpr expr = withSession $ \hsc_env -> do
965 Just (ids, hval) <- hscStmt hsc_env ("let __cmCompileExpr = "++expr)
967 hvals <- liftIO (unsafeCoerce# hval :: IO [HValue])
970 ([_],[hv]) -> return hv
971 _ -> panic "compileExpr"
973 -- -----------------------------------------------------------------------------
974 -- Compile an expression into a dynamic
976 dynCompileExpr :: GhcMonad m => String -> m Dynamic
977 dynCompileExpr expr = do
978 (full,exports) <- getContext
981 (stringToPackageId "base") (mkModuleName "Data.Dynamic")
983 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
984 Just (ids, hvals) <- withSession (flip hscStmt stmt)
985 setContext full exports
986 vals <- liftIO (unsafeCoerce# hvals :: IO [Dynamic])
988 (_:[], v:[]) -> return v
989 _ -> panic "dynCompileExpr"
991 -----------------------------------------------------------------------------
992 -- show a module and it's source/object filenames
994 showModule :: GhcMonad m => ModSummary -> m String
995 showModule mod_summary =
996 withSession $ \hsc_env -> do
997 interpreted <- isModuleInterpreted mod_summary
998 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
1000 isModuleInterpreted :: GhcMonad m => ModSummary -> m Bool
1001 isModuleInterpreted mod_summary = withSession $ \hsc_env ->
1002 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
1003 Nothing -> panic "missing linkable"
1004 Just mod_info -> return (not obj_linkable)
1006 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
1008 ----------------------------------------------------------------------------
1011 obtainTermFromVal :: HscEnv -> Int -> Bool -> Type -> a -> IO Term
1012 obtainTermFromVal hsc_env bound force ty x =
1013 cvObtainTerm hsc_env bound force ty (unsafeCoerce# x)
1015 obtainTermFromId :: HscEnv -> Int -> Bool -> Id -> IO Term
1016 obtainTermFromId hsc_env bound force id = do
1017 hv <- Linker.getHValue hsc_env (varName id)
1018 cvObtainTerm hsc_env bound force (idType id) hv
1020 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
1021 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
1022 reconstructType hsc_env bound id = do
1023 hv <- Linker.getHValue hsc_env (varName id)
1024 cvReconstructType hsc_env bound (idType id) hv