1 -- -----------------------------------------------------------------------------
3 -- (c) The University of Glasgow, 2005-2007
5 -- Running statements interactively
7 -- -----------------------------------------------------------------------------
10 -- The above warning supression flag is a temporary kludge.
11 -- While working on this module you are encouraged to remove it and fix
12 -- any warnings in the module. See
13 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 module InteractiveEval (
18 RunResult(..), Status(..), Resume(..), History(..),
19 runStmt, SingleStep(..),
27 setContext, getContext,
28 nameSetToGlobalRdrEnv,
38 compileExpr, dynCompileExpr,
40 Term(..), obtainTerm, obtainTerm1, obtainTermB, reconstructType,
41 skolemiseSubst, skolemiseTy
47 #include "HsVersions.h"
49 import HscMain hiding (compileExpr)
52 import Type hiding (typeKind)
53 import TcType hiding (typeKind)
55 import Var hiding (setIdType)
58 import Name hiding ( varName )
76 import RtClosureInspect
82 import Data.List (find)
88 import Control.Exception as Exception
89 import Control.Concurrent
90 import Data.List (sortBy)
92 import Foreign.StablePtr
94 -- -----------------------------------------------------------------------------
95 -- running a statement interactively
98 = RunOk [Name] -- ^ names bound by this evaluation
99 | RunFailed -- ^ statement failed compilation
100 | RunException Exception -- ^ statement raised an exception
101 | RunBreak ThreadId [Name] (Maybe BreakInfo)
104 = Break Bool HValue BreakInfo ThreadId
105 -- ^ the computation hit a breakpoint (Bool <=> was an exception)
106 | Complete (Either Exception [HValue])
107 -- ^ the computation completed with either an exception or a value
111 resumeStmt :: String, -- the original statement
112 resumeThreadId :: ThreadId, -- thread running the computation
113 resumeBreakMVar :: MVar (),
114 resumeStatMVar :: MVar Status,
115 resumeBindings :: ([Id], TyVarSet),
116 resumeFinalIds :: [Id], -- [Id] to bind on completion
117 resumeApStack :: HValue, -- The object from which we can get
118 -- value of the free variables.
119 resumeBreakInfo :: Maybe BreakInfo,
120 -- the breakpoint we stopped at
121 -- (Nothing <=> exception)
122 resumeSpan :: SrcSpan, -- just a cache, otherwise it's a pain
123 -- to fetch the ModDetails & ModBreaks
125 resumeHistory :: [History],
126 resumeHistoryIx :: Int -- 0 <==> at the top of the history
129 getResumeContext :: Session -> IO [Resume]
130 getResumeContext s = withSession s (return . ic_resume . hsc_IC)
137 isStep RunToCompletion = False
142 historyApStack :: HValue,
143 historyBreakInfo :: BreakInfo,
144 historyEnclosingDecl :: Id
145 -- ^^ A cache of the enclosing top level declaration, for convenience
148 mkHistory :: HscEnv -> HValue -> BreakInfo -> History
149 mkHistory hsc_env hval bi = let
150 h = History hval bi decl
151 decl = findEnclosingDecl hsc_env (getHistoryModule h)
152 (getHistorySpan hsc_env h)
155 getHistoryModule :: History -> Module
156 getHistoryModule = breakInfo_module . historyBreakInfo
158 getHistorySpan :: HscEnv -> History -> SrcSpan
159 getHistorySpan hsc_env hist =
160 let inf = historyBreakInfo hist
161 num = breakInfo_number inf
162 in case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
163 Just hmi -> modBreaks_locs (getModBreaks hmi) ! num
164 _ -> panic "getHistorySpan"
166 getModBreaks :: HomeModInfo -> ModBreaks
168 | Just linkable <- hm_linkable hmi,
169 [BCOs _ modBreaks] <- linkableUnlinked linkable
172 = emptyModBreaks -- probably object code
174 {- | Finds the enclosing top level function name -}
175 -- ToDo: a better way to do this would be to keep hold of the decl_path computed
176 -- by the coverage pass, which gives the list of lexically-enclosing bindings
178 findEnclosingDecl :: HscEnv -> Module -> SrcSpan -> Id
179 findEnclosingDecl hsc_env mod span =
180 case lookupUFM (hsc_HPT hsc_env) (moduleName mod) of
181 Nothing -> panic "findEnclosingDecl"
183 globals = typeEnvIds (md_types (hm_details hmi))
185 find (\id -> let n = idName id in
186 nameSrcSpan n < span && isExternalName n)
187 (reverse$ sortBy (compare `on` (nameSrcSpan.idName))
191 -- | Run a statement in the current interactive context. Statement
192 -- may bind multple values.
193 runStmt :: Session -> String -> SingleStep -> IO RunResult
194 runStmt (Session ref) expr step
196 hsc_env <- readIORef ref
198 breakMVar <- newEmptyMVar -- wait on this when we hit a breakpoint
199 statusMVar <- newEmptyMVar -- wait on this when a computation is running
201 -- Turn off -fwarn-unused-bindings when running a statement, to hide
202 -- warnings about the implicit bindings we introduce.
203 let dflags' = dopt_unset (hsc_dflags hsc_env) Opt_WarnUnusedBinds
204 hsc_env' = hsc_env{ hsc_dflags = dflags' }
206 maybe_stuff <- hscStmt hsc_env' expr
209 Nothing -> return RunFailed
210 Just (ids, hval) -> do
212 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
214 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
215 status <- sandboxIO dflags' statusMVar thing_to_run
217 let ic = hsc_IC hsc_env
218 bindings = (ic_tmp_ids ic, ic_tyvars ic)
222 traceRunStatus expr ref bindings ids
223 breakMVar statusMVar status emptyHistory
225 handleRunStatus expr ref bindings ids
226 breakMVar statusMVar status emptyHistory
229 emptyHistory = nilBL 50 -- keep a log of length 50
231 handleRunStatus expr ref bindings final_ids breakMVar statusMVar status
234 -- did we hit a breakpoint or did we complete?
235 (Break is_exception apStack info tid) -> do
236 hsc_env <- readIORef ref
237 let mb_info | is_exception = Nothing
238 | otherwise = Just info
239 (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
242 resume = Resume expr tid breakMVar statusMVar
243 bindings final_ids apStack mb_info span
245 hsc_env2 = pushResume hsc_env1 resume
247 writeIORef ref hsc_env2
248 return (RunBreak tid names mb_info)
249 (Complete either_hvals) ->
251 Left e -> return (RunException e)
253 hsc_env <- readIORef ref
254 let final_ic = extendInteractiveContext (hsc_IC hsc_env)
255 final_ids emptyVarSet
256 -- the bound Ids never have any free TyVars
257 final_names = map idName final_ids
258 Linker.extendLinkEnv (zip final_names hvals)
259 hsc_env' <- rttiEnvironment hsc_env{hsc_IC=final_ic}
260 writeIORef ref hsc_env'
261 return (RunOk final_names)
264 traceRunStatus expr ref bindings final_ids
265 breakMVar statusMVar status history = do
266 hsc_env <- readIORef ref
268 -- when tracing, if we hit a breakpoint that is not explicitly
269 -- enabled, then we just log the event in the history and continue.
270 (Break is_exception apStack info tid) | not is_exception -> do
271 b <- isBreakEnabled hsc_env info
275 let history' = mkHistory hsc_env apStack info `consBL` history
276 -- probably better make history strict here, otherwise
277 -- our BoundedList will be pointless.
279 status <- withBreakAction True (hsc_dflags hsc_env)
280 breakMVar statusMVar $ do
282 (do putMVar breakMVar () -- awaken the stopped thread
284 (takeMVar statusMVar) -- and wait for the result
285 traceRunStatus expr ref bindings final_ids
286 breakMVar statusMVar status history'
290 handle_normally = handleRunStatus expr ref bindings final_ids
291 breakMVar statusMVar status history
294 isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
295 isBreakEnabled hsc_env inf =
296 case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
298 w <- getBreak (modBreaks_flags (getModBreaks hmi))
299 (breakInfo_number inf)
300 case w of Just n -> return (n /= 0); _other -> return False
305 foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
306 foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
308 setStepFlag = poke stepFlag 1
309 resetStepFlag = poke stepFlag 0
311 -- this points to the IO action that is executed when a breakpoint is hit
312 foreign import ccall "&rts_breakpoint_io_action"
313 breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
315 -- When running a computation, we redirect ^C exceptions to the running
316 -- thread. ToDo: we might want a way to continue even if the target
317 -- thread doesn't die when it receives the exception... "this thread
318 -- is not responding".
319 sandboxIO :: DynFlags -> MVar Status -> IO [HValue] -> IO Status
320 sandboxIO dflags statusMVar thing =
322 (forkIO (do res <- Exception.try (rethrow dflags thing)
323 putMVar statusMVar (Complete res)))
324 (takeMVar statusMVar)
326 -- We want to turn ^C into a break when -fbreak-on-exception is on,
327 -- but it's an async exception and we only break for sync exceptions.
328 -- Idea: if we catch and re-throw it, then the re-throw will trigger
329 -- a break. Great - but we don't want to re-throw all exceptions, because
330 -- then we'll get a double break for ordinary sync exceptions (you'd have
331 -- to :continue twice, which looks strange). So if the exception is
332 -- not "Interrupted", we unset the exception flag before throwing.
334 rethrow :: DynFlags -> IO a -> IO a
335 rethrow dflags io = Exception.catch io $ \e -> do -- NB. not catchDyn
337 -- If -fbreak-on-error, we break unconditionally,
338 -- but with care of not breaking twice
339 _ | dopt Opt_BreakOnError dflags &&
340 not(dopt Opt_BreakOnException dflags)
341 -> poke exceptionFlag 1
343 -- If it is an "Interrupted" exception, we allow
344 -- a possible break by way of -fbreak-on-exception
345 DynException d | Just Interrupted <- fromDynamic d
348 -- In any other case, we don't want to break
349 _ -> poke exceptionFlag 0
354 withInterruptsSentTo :: IO ThreadId -> IO r -> IO r
355 withInterruptsSentTo io get_result = do
356 ts <- takeMVar interruptTargetThread
358 putMVar interruptTargetThread (child:ts)
359 get_result `finally` modifyMVar_ interruptTargetThread (return.tail)
361 -- This function sets up the interpreter for catching breakpoints, and
362 -- resets everything when the computation has stopped running. This
363 -- is a not-very-good way to ensure that only the interactive
364 -- evaluation should generate breakpoints.
365 withBreakAction step dflags breakMVar statusMVar io
366 = bracket setBreakAction resetBreakAction (\_ -> io)
369 stablePtr <- newStablePtr onBreak
370 poke breakPointIOAction stablePtr
371 when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
372 when step $ setStepFlag
374 -- Breaking on exceptions is not enabled by default, since it
375 -- might be a bit surprising. The exception flag is turned off
376 -- as soon as it is hit, or in resetBreakAction below.
378 onBreak is_exception info apStack = do
380 putMVar statusMVar (Break is_exception apStack info tid)
383 resetBreakAction stablePtr = do
384 poke breakPointIOAction noBreakStablePtr
387 freeStablePtr stablePtr
389 noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
391 noBreakAction False info apStack = putStrLn "*** Ignoring breakpoint"
392 noBreakAction True info apStack = return () -- exception: just continue
394 resume :: Session -> SingleStep -> IO RunResult
395 resume (Session ref) step
397 hsc_env <- readIORef ref
398 let ic = hsc_IC hsc_env
399 resume = ic_resume ic
402 [] -> throwDyn (ProgramError "not stopped at a breakpoint")
404 -- unbind the temporary locals by restoring the TypeEnv from
405 -- before the breakpoint, and drop this Resume from the
406 -- InteractiveContext.
407 let (resume_tmp_ids, resume_tyvars) = resumeBindings r
408 ic' = ic { ic_tmp_ids = resume_tmp_ids,
409 ic_tyvars = resume_tyvars,
411 writeIORef ref hsc_env{ hsc_IC = ic' }
413 -- remove any bindings created since the breakpoint from the
414 -- linker's environment
415 let new_names = map idName (filter (`notElem` resume_tmp_ids)
417 Linker.deleteFromLinkEnv new_names
419 when (isStep step) $ setStepFlag
421 Resume expr tid breakMVar statusMVar bindings
422 final_ids apStack info _ hist _ -> do
423 withBreakAction (isStep step) (hsc_dflags hsc_env)
424 breakMVar statusMVar $ do
425 status <- withInterruptsSentTo
426 (do putMVar breakMVar ()
427 -- this awakens the stopped thread...
429 (takeMVar statusMVar)
430 -- and wait for the result
433 Nothing -> fromListBL 50 hist
434 Just i -> mkHistory hsc_env apStack i `consBL`
438 traceRunStatus expr ref bindings final_ids
439 breakMVar statusMVar status hist'
441 handleRunStatus expr ref bindings final_ids
442 breakMVar statusMVar status hist'
445 back :: Session -> IO ([Name], Int, SrcSpan)
448 forward :: Session -> IO ([Name], Int, SrcSpan)
449 forward = moveHist (subtract 1)
451 moveHist fn (Session ref) = do
452 hsc_env <- readIORef ref
453 case ic_resume (hsc_IC hsc_env) of
454 [] -> throwDyn (ProgramError "not stopped at a breakpoint")
456 let ix = resumeHistoryIx r
457 history = resumeHistory r
460 when (new_ix > length history) $
461 throwDyn (ProgramError "no more logged breakpoints")
463 throwDyn (ProgramError "already at the beginning of the history")
466 update_ic apStack mb_info = do
467 (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
469 let ic = hsc_IC hsc_env1
470 r' = r { resumeHistoryIx = new_ix }
471 ic' = ic { ic_resume = r':rs }
473 writeIORef ref hsc_env1{ hsc_IC = ic' }
475 return (names, new_ix, span)
477 -- careful: we want apStack to be the AP_STACK itself, not a thunk
478 -- around it, hence the cases are carefully constructed below to
479 -- make this the case. ToDo: this is v. fragile, do something better.
482 Resume { resumeApStack = apStack,
483 resumeBreakInfo = mb_info } ->
484 update_ic apStack mb_info
485 else case history !! (new_ix - 1) of
486 History apStack info _ ->
487 update_ic apStack (Just info)
489 -- -----------------------------------------------------------------------------
490 -- After stopping at a breakpoint, add free variables to the environment
491 result_fs = FSLIT("_result")
493 bindLocalsAtBreakpoint
497 -> IO (HscEnv, [Name], SrcSpan)
499 -- Nothing case: we stopped when an exception was raised, not at a
500 -- breakpoint. We have no location information or local variables to
501 -- bind, all we can do is bind a local variable to the exception
503 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
504 let exn_fs = FSLIT("_exception")
505 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
507 e_name = mkInternalName (getUnique e_fs) (mkTyVarOcc e_fs) span
508 e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
509 exn_id = Id.mkGlobalId VanillaGlobal exn_name (mkTyVarTy e_tyvar)
511 new_tyvars = unitVarSet e_tyvar
513 ictxt0 = hsc_IC hsc_env
514 ictxt1 = extendInteractiveContext ictxt0 [exn_id] new_tyvars
516 span = mkGeneralSrcSpan FSLIT("<exception thrown>")
518 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
519 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
521 -- Just case: we stopped at a breakpoint, we have information about the location
522 -- of the breakpoint and the free variables of the expression.
523 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
526 mod_name = moduleName (breakInfo_module info)
527 hmi = expectJust "bindLocalsAtBreakpoint" $
528 lookupUFM (hsc_HPT hsc_env) mod_name
529 breaks = getModBreaks hmi
530 index = breakInfo_number info
531 vars = breakInfo_vars info
532 result_ty = breakInfo_resty info
533 occs = modBreaks_vars breaks ! index
534 span = modBreaks_locs breaks ! index
536 -- filter out any unboxed ids; we can't bind these at the prompt
537 let pointers = filter (\(id,_) -> isPointer id) vars
538 isPointer id | PtrRep <- idPrimRep id = True
541 let (ids, offsets) = unzip pointers
543 -- It might be that getIdValFromApStack fails, because the AP_STACK
544 -- has been accidentally evaluated, or something else has gone wrong.
545 -- So that we don't fall over in a heap when this happens, just don't
546 -- bind any free variables instead, and we emit a warning.
547 mb_hValues <- mapM (getIdValFromApStack apStack) offsets
548 let filtered_ids = [ id | (id, Just hv) <- zip ids mb_hValues ]
549 when (any isNothing mb_hValues) $
550 debugTraceMsg (hsc_dflags hsc_env) 1 $
551 text "Warning: _result has been evaluated, some bindings have been lost"
553 new_ids <- zipWithM mkNewId occs filtered_ids
554 let names = map idName new_ids
556 -- make an Id for _result. We use the Unique of the FastString "_result";
557 -- we don't care about uniqueness here, because there will only be one
558 -- _result in scope at any time.
559 let result_name = mkInternalName (getUnique result_fs)
560 (mkVarOccFS result_fs) span
561 result_id = Id.mkGlobalId VanillaGlobal result_name result_ty
564 -- for each Id we're about to bind in the local envt:
565 -- - skolemise the type variables in its type, so they can't
566 -- be randomly unified with other types. These type variables
567 -- can only be resolved by type reconstruction in RtClosureInspect
568 -- - tidy the type variables
569 -- - globalise the Id (Ids are supposed to be Global, apparently).
571 let all_ids | isPointer result_id = result_id : new_ids
572 | otherwise = new_ids
573 (id_tys, tyvarss) = mapAndUnzip (skolemiseTy.idType) all_ids
574 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
575 new_tyvars = unionVarSets tyvarss
576 let final_ids = zipWith setIdType all_ids tidy_tys
577 ictxt0 = hsc_IC hsc_env
578 ictxt1 = extendInteractiveContext ictxt0 final_ids new_tyvars
579 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
580 Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
581 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
582 return (hsc_env1, result_name:names, span)
584 mkNewId :: OccName -> Id -> IO Id
586 us <- mkSplitUniqSupply 'I'
587 -- we need a fresh Unique for each Id we bind, because the linker
588 -- state is single-threaded and otherwise we'd spam old bindings
589 -- whenever we stop at a breakpoint. The InteractveContext is properly
590 -- saved/restored, but not the linker state. See #1743, test break026.
592 uniq = uniqFromSupply us
593 loc = nameSrcSpan (idName id)
594 name = mkInternalName uniq occ loc
596 new_id = Id.mkGlobalId VanillaGlobal name ty (idInfo id)
599 rttiEnvironment :: HscEnv -> IO HscEnv
600 rttiEnvironment hsc_env@HscEnv{hsc_IC=ic} = do
601 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
602 incompletelyTypedIds =
604 , not $ null [v | v <- varSetElems$ tyVarsOfType (idType id)
606 , (occNameFS.nameOccName.idName) id /= result_fs]
607 tys <- reconstructType hsc_env 10 `mapM` incompletelyTypedIds
608 -- map termType `fmap` (obtainTerm hsc_env False `mapM` incompletelyTypedIds)
610 let substs = [computeRTTIsubst ty ty'
611 | (ty, Just ty') <- zip (map idType incompletelyTypedIds) tys]
612 ic' = foldr (flip substInteractiveContext) ic
613 (map skolemiseSubst $ catMaybes substs)
614 return hsc_env{hsc_IC=ic'}
616 skolemiseSubst subst = subst `setTvSubstEnv`
617 mapVarEnv (fst.skolemiseTy) (getTvSubstEnv subst)
619 skolemiseTy :: Type -> (Type, TyVarSet)
620 skolemiseTy ty = (substTy subst ty, mkVarSet new_tyvars)
621 where env = mkVarEnv (zip tyvars new_tyvar_tys)
622 subst = mkTvSubst emptyInScopeSet env
623 tyvars = varSetElems (tyVarsOfType ty)
624 new_tyvars = map skolemiseTyVar tyvars
625 new_tyvar_tys = map mkTyVarTy new_tyvars
627 skolemiseTyVar :: TyVar -> TyVar
628 skolemiseTyVar tyvar = mkTcTyVar (tyVarName tyvar) (tyVarKind tyvar)
629 (SkolemTv RuntimeUnkSkol)
631 getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
632 getIdValFromApStack apStack (I# stackDepth) = do
633 case getApStackVal# apStack (stackDepth +# 1#) of
634 -- The +1 is magic! I don't know where it comes
635 -- from, but this makes things line up. --SDM
638 0# -> return Nothing -- AP_STACK not found
639 _ -> return (Just (unsafeCoerce# result))
641 pushResume :: HscEnv -> Resume -> HscEnv
642 pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
644 ictxt0 = hsc_IC hsc_env
645 ictxt1 = ictxt0 { ic_resume = resume : ic_resume ictxt0 }
647 -- -----------------------------------------------------------------------------
648 -- Abandoning a resume context
650 abandon :: Session -> IO Bool
651 abandon (Session ref) = do
652 hsc_env <- readIORef ref
653 let ic = hsc_IC hsc_env
654 resume = ic_resume ic
658 writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = rs } }
662 abandonAll :: Session -> IO Bool
663 abandonAll (Session ref) = do
664 hsc_env <- readIORef ref
665 let ic = hsc_IC hsc_env
666 resume = ic_resume ic
670 writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = [] } }
674 -- when abandoning a computation we have to
675 -- (a) kill the thread with an async exception, so that the
676 -- computation itself is stopped, and
677 -- (b) fill in the MVar. This step is necessary because any
678 -- thunks that were under evaluation will now be updated
679 -- with the partial computation, which still ends in takeMVar,
680 -- so any attempt to evaluate one of these thunks will block
681 -- unless we fill in the MVar.
682 -- See test break010.
683 abandon_ :: Resume -> IO ()
685 killThread (resumeThreadId r)
686 putMVar (resumeBreakMVar r) ()
688 -- -----------------------------------------------------------------------------
689 -- Bounded list, optimised for repeated cons
691 data BoundedList a = BL
692 {-# UNPACK #-} !Int -- length
693 {-# UNPACK #-} !Int -- bound
695 [a] -- right, list is (left ++ reverse right)
697 nilBL :: Int -> BoundedList a
698 nilBL bound = BL 0 bound [] []
700 consBL a (BL len bound left right)
701 | len < bound = BL (len+1) bound (a:left) right
702 | null right = BL len bound [a] $! tail (reverse left)
703 | otherwise = BL len bound (a:left) $! tail right
705 toListBL (BL _ _ left right) = left ++ reverse right
707 fromListBL bound l = BL (length l) bound l []
709 -- lenBL (BL len _ _ _) = len
711 -- -----------------------------------------------------------------------------
712 -- | Set the interactive evaluation context.
714 -- Setting the context doesn't throw away any bindings; the bindings
715 -- we've built up in the InteractiveContext simply move to the new
716 -- module. They always shadow anything in scope in the current context.
717 setContext :: Session
718 -> [Module] -- entire top level scope of these modules
719 -> [Module] -- exports only of these modules
721 setContext sess@(Session ref) toplev_mods export_mods = do
722 hsc_env <- readIORef ref
723 let old_ic = hsc_IC hsc_env
724 hpt = hsc_HPT hsc_env
726 export_env <- mkExportEnv hsc_env export_mods
727 toplev_envs <- mapM (mkTopLevEnv hpt) toplev_mods
728 let all_env = foldr plusGlobalRdrEnv export_env toplev_envs
729 writeIORef ref hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
730 ic_exports = export_mods,
731 ic_rn_gbl_env = all_env }}
733 -- Make a GlobalRdrEnv based on the exports of the modules only.
734 mkExportEnv :: HscEnv -> [Module] -> IO GlobalRdrEnv
735 mkExportEnv hsc_env mods = do
736 stuff <- mapM (getModuleExports hsc_env) mods
738 (_msgs, mb_name_sets) = unzip stuff
739 gres = [ nameSetToGlobalRdrEnv (availsToNameSet avails) (moduleName mod)
740 | (Just avails, mod) <- zip mb_name_sets mods ]
742 return $! foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres
744 nameSetToGlobalRdrEnv :: NameSet -> ModuleName -> GlobalRdrEnv
745 nameSetToGlobalRdrEnv names mod =
746 mkGlobalRdrEnv [ GRE { gre_name = name, gre_par = NoParent, gre_prov = vanillaProv mod }
747 | name <- nameSetToList names ]
749 vanillaProv :: ModuleName -> Provenance
750 -- We're building a GlobalRdrEnv as if the user imported
751 -- all the specified modules into the global interactive module
752 vanillaProv mod_name = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
754 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
756 is_dloc = srcLocSpan interactiveSrcLoc }
758 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
760 = case lookupUFM hpt (moduleName modl) of
761 Nothing -> throwDyn (ProgramError ("mkTopLevEnv: not a home module " ++
762 showSDoc (ppr modl)))
764 case mi_globals (hm_iface details) of
766 throwDyn (ProgramError ("mkTopLevEnv: not interpreted "
767 ++ showSDoc (ppr modl)))
768 Just env -> return env
770 -- | Get the interactive evaluation context, consisting of a pair of the
771 -- set of modules from which we take the full top-level scope, and the set
772 -- of modules from which we take just the exports respectively.
773 getContext :: Session -> IO ([Module],[Module])
774 getContext s = withSession s (\HscEnv{ hsc_IC=ic } ->
775 return (ic_toplev_scope ic, ic_exports ic))
777 -- | Returns 'True' if the specified module is interpreted, and hence has
778 -- its full top-level scope available.
779 moduleIsInterpreted :: Session -> Module -> IO Bool
780 moduleIsInterpreted s modl = withSession s $ \h ->
781 if modulePackageId modl /= thisPackage (hsc_dflags h)
783 else case lookupUFM (hsc_HPT h) (moduleName modl) of
784 Just details -> return (isJust (mi_globals (hm_iface details)))
785 _not_a_home_module -> return False
787 -- | Looks up an identifier in the current interactive context (for :info)
788 -- Filter the instances by the ones whose tycons (or clases resp)
789 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
790 -- The exact choice of which ones to show, and which to hide, is a judgement call.
792 getInfo :: Session -> Name -> IO (Maybe (TyThing,Fixity,[Instance]))
794 = withSession s $ \hsc_env ->
795 do { mb_stuff <- tcRnGetInfo hsc_env name
797 Nothing -> return Nothing
798 Just (thing, fixity, ispecs) -> do
799 { let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
800 ; return (Just (thing, fixity, filter (plausible rdr_env) ispecs)) } }
802 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
803 = all ok $ nameSetToList $ tyClsNamesOfType $ idType $ instanceDFunId ispec
804 where -- A name is ok if it's in the rdr_env,
805 -- whether qualified or not
806 ok n | n == name = True -- The one we looked for in the first place!
807 | isBuiltInSyntax n = True
808 | isExternalName n = any ((== n) . gre_name)
809 (lookupGRE_Name rdr_env n)
812 -- | Returns all names in scope in the current interactive context
813 getNamesInScope :: Session -> IO [Name]
814 getNamesInScope s = withSession s $ \hsc_env -> do
815 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
817 getRdrNamesInScope :: Session -> IO [RdrName]
818 getRdrNamesInScope s = withSession s $ \hsc_env -> do
821 gbl_rdrenv = ic_rn_gbl_env ic
823 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
824 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
826 return (gbl_names ++ lcl_names)
829 -- ToDo: move to RdrName
830 greToRdrNames :: GlobalRdrElt -> [RdrName]
831 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
834 Imported specs -> concat (map do_spec (map is_decl specs))
836 occ = nameOccName name
839 | is_qual decl_spec = [qual]
840 | otherwise = [unqual,qual]
841 where qual = Qual (is_as decl_spec) occ
843 -- | Parses a string as an identifier, and returns the list of 'Name's that
844 -- the identifier can refer to in the current interactive context.
845 parseName :: Session -> String -> IO [Name]
846 parseName s str = withSession s $ \hsc_env -> do
847 maybe_rdr_name <- hscParseIdentifier (hsc_dflags hsc_env) str
848 case maybe_rdr_name of
850 Just (L _ rdr_name) -> do
851 mb_names <- tcRnLookupRdrName hsc_env rdr_name
855 -- ToDo: should return error messages
857 -- | Returns the 'TyThing' for a 'Name'. The 'Name' may refer to any
858 -- entity known to GHC, including 'Name's defined using 'runStmt'.
859 lookupName :: Session -> Name -> IO (Maybe TyThing)
860 lookupName s name = withSession s $ \hsc_env -> tcRnLookupName hsc_env name
862 -- -----------------------------------------------------------------------------
863 -- Getting the type of an expression
865 -- | Get the type of an expression
866 exprType :: Session -> String -> IO (Maybe Type)
867 exprType s expr = withSession s $ \hsc_env -> do
868 maybe_stuff <- hscTcExpr hsc_env expr
870 Nothing -> return Nothing
871 Just ty -> return (Just tidy_ty)
873 tidy_ty = tidyType emptyTidyEnv ty
875 -- -----------------------------------------------------------------------------
876 -- Getting the kind of a type
878 -- | Get the kind of a type
879 typeKind :: Session -> String -> IO (Maybe Kind)
880 typeKind s str = withSession s $ \hsc_env -> do
881 maybe_stuff <- hscKcType hsc_env str
883 Nothing -> return Nothing
884 Just kind -> return (Just kind)
886 -----------------------------------------------------------------------------
887 -- cmCompileExpr: compile an expression and deliver an HValue
889 compileExpr :: Session -> String -> IO (Maybe HValue)
890 compileExpr s expr = withSession s $ \hsc_env -> do
891 maybe_stuff <- hscStmt hsc_env ("let __cmCompileExpr = "++expr)
893 Nothing -> return Nothing
894 Just (ids, hval) -> do
896 hvals <- (unsafeCoerce# hval) :: IO [HValue]
899 ([n],[hv]) -> return (Just hv)
900 _ -> panic "compileExpr"
902 -- -----------------------------------------------------------------------------
903 -- Compile an expression into a dynamic
905 dynCompileExpr :: Session -> String -> IO (Maybe Dynamic)
906 dynCompileExpr ses expr = do
907 (full,exports) <- getContext ses
908 setContext ses full $
910 (stringToPackageId "base") (mkModuleName "Data.Dynamic")
912 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
913 res <- withSession ses (flip hscStmt stmt)
914 setContext ses full exports
916 Nothing -> return Nothing
917 Just (ids, hvals) -> do
918 vals <- (unsafeCoerce# hvals :: IO [Dynamic])
920 (_:[], v:[]) -> return (Just v)
921 _ -> panic "dynCompileExpr"
923 -----------------------------------------------------------------------------
924 -- show a module and it's source/object filenames
926 showModule :: Session -> ModSummary -> IO String
927 showModule s mod_summary = withSession s $ \hsc_env ->
928 isModuleInterpreted s mod_summary >>= \interpreted ->
929 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
931 isModuleInterpreted :: Session -> ModSummary -> IO Bool
932 isModuleInterpreted s mod_summary = withSession s $ \hsc_env ->
933 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
934 Nothing -> panic "missing linkable"
935 Just mod_info -> return (not obj_linkable)
937 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
939 ----------------------------------------------------------------------------
942 obtainTerm1 :: HscEnv -> Bool -> Maybe Type -> a -> IO Term
943 obtainTerm1 hsc_env force mb_ty x =
944 cvObtainTerm hsc_env maxBound force mb_ty (unsafeCoerce# x)
946 obtainTermB :: HscEnv -> Int -> Bool -> Id -> IO Term
947 obtainTermB hsc_env bound force id = do
948 hv <- Linker.getHValue hsc_env (varName id)
949 cvObtainTerm hsc_env bound force (Just$ idType id) hv
951 obtainTerm :: HscEnv -> Bool -> Id -> IO Term
952 obtainTerm hsc_env force id = do
953 hv <- Linker.getHValue hsc_env (varName id)
954 cvObtainTerm hsc_env maxBound force (Just$ idType id) hv
956 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
957 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
958 reconstructType hsc_env bound id = do
959 hv <- Linker.getHValue hsc_env (varName id)
960 cvReconstructType hsc_env bound (Just$ idType id) hv