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
213 withBreakAction (isStep step) dflags' breakMVar statusMVar $ do
214 let thing_to_run = unsafeCoerce# hval :: IO [HValue]
215 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
281 withInterruptsSentTo tid $ do
282 putMVar breakMVar () -- awaken the stopped thread
283 takeMVar statusMVar -- and wait for the result
284 traceRunStatus expr ref bindings final_ids
285 breakMVar statusMVar status history'
289 handle_normally = handleRunStatus expr ref bindings final_ids
290 breakMVar statusMVar status history
293 isBreakEnabled :: HscEnv -> BreakInfo -> IO Bool
294 isBreakEnabled hsc_env inf =
295 case lookupUFM (hsc_HPT hsc_env) (moduleName (breakInfo_module inf)) of
297 w <- getBreak (modBreaks_flags (getModBreaks hmi))
298 (breakInfo_number inf)
299 case w of Just n -> return (n /= 0); _other -> return False
304 foreign import ccall "&rts_stop_next_breakpoint" stepFlag :: Ptr CInt
305 foreign import ccall "&rts_stop_on_exception" exceptionFlag :: Ptr CInt
307 setStepFlag = poke stepFlag 1
308 resetStepFlag = poke stepFlag 0
310 -- this points to the IO action that is executed when a breakpoint is hit
311 foreign import ccall "&rts_breakpoint_io_action"
312 breakPointIOAction :: Ptr (StablePtr (Bool -> BreakInfo -> HValue -> IO ()))
314 -- When running a computation, we redirect ^C exceptions to the running
315 -- thread. ToDo: we might want a way to continue even if the target
316 -- thread doesn't die when it receives the exception... "this thread
317 -- is not responding".
319 -- Careful here: there may be ^C exceptions flying around, so we start
320 -- the new thread blocked (forkIO inherits block from the parent,
321 -- #1048), and unblock only while we execute the user's code. We
322 -- can't afford to lose the final putMVar, otherwise deadlock
323 -- ensues. (#1583, #1922, #1946)
324 sandboxIO :: DynFlags -> MVar Status -> IO [HValue] -> IO Status
325 sandboxIO dflags statusMVar thing =
326 block $ do -- fork starts blocked
327 id <- forkIO $ do res <- Exception.try (unblock $ rethrow dflags thing)
328 putMVar statusMVar (Complete res) -- empty: can't block
329 withInterruptsSentTo id $ takeMVar statusMVar
332 -- We want to turn ^C into a break when -fbreak-on-exception is on,
333 -- but it's an async exception and we only break for sync exceptions.
334 -- Idea: if we catch and re-throw it, then the re-throw will trigger
335 -- a break. Great - but we don't want to re-throw all exceptions, because
336 -- then we'll get a double break for ordinary sync exceptions (you'd have
337 -- to :continue twice, which looks strange). So if the exception is
338 -- not "Interrupted", we unset the exception flag before throwing.
340 rethrow :: DynFlags -> IO a -> IO a
341 rethrow dflags io = Exception.catch io $ \e -> do -- NB. not catchDyn
343 -- If -fbreak-on-error, we break unconditionally,
344 -- but with care of not breaking twice
345 _ | dopt Opt_BreakOnError dflags &&
346 not(dopt Opt_BreakOnException dflags)
347 -> poke exceptionFlag 1
349 -- If it is an "Interrupted" exception, we allow
350 -- a possible break by way of -fbreak-on-exception
351 DynException d | Just Interrupted <- fromDynamic d
354 -- In any other case, we don't want to break
355 _ -> poke exceptionFlag 0
360 withInterruptsSentTo :: ThreadId -> IO r -> IO r
361 withInterruptsSentTo thread get_result = do
362 bracket (modifyMVar_ interruptTargetThread (return . (thread:)))
363 (\_ -> modifyMVar_ interruptTargetThread (return.tail))
366 -- This function sets up the interpreter for catching breakpoints, and
367 -- resets everything when the computation has stopped running. This
368 -- is a not-very-good way to ensure that only the interactive
369 -- evaluation should generate breakpoints.
370 withBreakAction step dflags breakMVar statusMVar io
371 = bracket setBreakAction resetBreakAction (\_ -> io)
374 stablePtr <- newStablePtr onBreak
375 poke breakPointIOAction stablePtr
376 when (dopt Opt_BreakOnException dflags) $ poke exceptionFlag 1
377 when step $ setStepFlag
379 -- Breaking on exceptions is not enabled by default, since it
380 -- might be a bit surprising. The exception flag is turned off
381 -- as soon as it is hit, or in resetBreakAction below.
383 onBreak is_exception info apStack = do
385 putMVar statusMVar (Break is_exception apStack info tid)
388 resetBreakAction stablePtr = do
389 poke breakPointIOAction noBreakStablePtr
392 freeStablePtr stablePtr
394 noBreakStablePtr = unsafePerformIO $ newStablePtr noBreakAction
396 noBreakAction False info apStack = putStrLn "*** Ignoring breakpoint"
397 noBreakAction True info apStack = return () -- exception: just continue
399 resume :: Session -> SingleStep -> IO RunResult
400 resume (Session ref) step
402 hsc_env <- readIORef ref
403 let ic = hsc_IC hsc_env
404 resume = ic_resume ic
407 [] -> throwDyn (ProgramError "not stopped at a breakpoint")
409 -- unbind the temporary locals by restoring the TypeEnv from
410 -- before the breakpoint, and drop this Resume from the
411 -- InteractiveContext.
412 let (resume_tmp_ids, resume_tyvars) = resumeBindings r
413 ic' = ic { ic_tmp_ids = resume_tmp_ids,
414 ic_tyvars = resume_tyvars,
416 writeIORef ref hsc_env{ hsc_IC = ic' }
418 -- remove any bindings created since the breakpoint from the
419 -- linker's environment
420 let new_names = map idName (filter (`notElem` resume_tmp_ids)
422 Linker.deleteFromLinkEnv new_names
424 when (isStep step) $ setStepFlag
426 Resume expr tid breakMVar statusMVar bindings
427 final_ids apStack info _ hist _ -> do
428 withBreakAction (isStep step) (hsc_dflags hsc_env)
429 breakMVar statusMVar $ do
430 status <- withInterruptsSentTo tid $ do
432 -- this awakens the stopped thread...
434 -- and wait for the result
437 Nothing -> fromListBL 50 hist
438 Just i -> mkHistory hsc_env apStack i `consBL`
442 traceRunStatus expr ref bindings final_ids
443 breakMVar statusMVar status hist'
445 handleRunStatus expr ref bindings final_ids
446 breakMVar statusMVar status hist'
448 back :: Session -> IO ([Name], Int, SrcSpan)
451 forward :: Session -> IO ([Name], Int, SrcSpan)
452 forward = moveHist (subtract 1)
454 moveHist fn (Session ref) = do
455 hsc_env <- readIORef ref
456 case ic_resume (hsc_IC hsc_env) of
457 [] -> throwDyn (ProgramError "not stopped at a breakpoint")
459 let ix = resumeHistoryIx r
460 history = resumeHistory r
463 when (new_ix > length history) $
464 throwDyn (ProgramError "no more logged breakpoints")
466 throwDyn (ProgramError "already at the beginning of the history")
469 update_ic apStack mb_info = do
470 (hsc_env1, names, span) <- bindLocalsAtBreakpoint hsc_env
472 let ic = hsc_IC hsc_env1
473 r' = r { resumeHistoryIx = new_ix }
474 ic' = ic { ic_resume = r':rs }
476 writeIORef ref hsc_env1{ hsc_IC = ic' }
478 return (names, new_ix, span)
480 -- careful: we want apStack to be the AP_STACK itself, not a thunk
481 -- around it, hence the cases are carefully constructed below to
482 -- make this the case. ToDo: this is v. fragile, do something better.
485 Resume { resumeApStack = apStack,
486 resumeBreakInfo = mb_info } ->
487 update_ic apStack mb_info
488 else case history !! (new_ix - 1) of
489 History apStack info _ ->
490 update_ic apStack (Just info)
492 -- -----------------------------------------------------------------------------
493 -- After stopping at a breakpoint, add free variables to the environment
494 result_fs = FSLIT("_result")
496 bindLocalsAtBreakpoint
500 -> IO (HscEnv, [Name], SrcSpan)
502 -- Nothing case: we stopped when an exception was raised, not at a
503 -- breakpoint. We have no location information or local variables to
504 -- bind, all we can do is bind a local variable to the exception
506 bindLocalsAtBreakpoint hsc_env apStack Nothing = do
507 let exn_fs = FSLIT("_exception")
508 exn_name = mkInternalName (getUnique exn_fs) (mkVarOccFS exn_fs) span
510 e_name = mkInternalName (getUnique e_fs) (mkTyVarOcc e_fs) span
511 e_tyvar = mkTcTyVar e_name liftedTypeKind (SkolemTv RuntimeUnkSkol)
512 exn_id = Id.mkGlobalId VanillaGlobal exn_name (mkTyVarTy e_tyvar)
514 new_tyvars = unitVarSet e_tyvar
516 ictxt0 = hsc_IC hsc_env
517 ictxt1 = extendInteractiveContext ictxt0 [exn_id] new_tyvars
519 span = mkGeneralSrcSpan FSLIT("<exception thrown>")
521 Linker.extendLinkEnv [(exn_name, unsafeCoerce# apStack)]
522 return (hsc_env{ hsc_IC = ictxt1 }, [exn_name], span)
524 -- Just case: we stopped at a breakpoint, we have information about the location
525 -- of the breakpoint and the free variables of the expression.
526 bindLocalsAtBreakpoint hsc_env apStack (Just info) = do
529 mod_name = moduleName (breakInfo_module info)
530 hmi = expectJust "bindLocalsAtBreakpoint" $
531 lookupUFM (hsc_HPT hsc_env) mod_name
532 breaks = getModBreaks hmi
533 index = breakInfo_number info
534 vars = breakInfo_vars info
535 result_ty = breakInfo_resty info
536 occs = modBreaks_vars breaks ! index
537 span = modBreaks_locs breaks ! index
539 -- filter out any unboxed ids; we can't bind these at the prompt
540 let pointers = filter (\(id,_) -> isPointer id) vars
541 isPointer id | PtrRep <- idPrimRep id = True
544 let (ids, offsets) = unzip pointers
546 -- It might be that getIdValFromApStack fails, because the AP_STACK
547 -- has been accidentally evaluated, or something else has gone wrong.
548 -- So that we don't fall over in a heap when this happens, just don't
549 -- bind any free variables instead, and we emit a warning.
550 mb_hValues <- mapM (getIdValFromApStack apStack) offsets
551 let filtered_ids = [ id | (id, Just hv) <- zip ids mb_hValues ]
552 when (any isNothing mb_hValues) $
553 debugTraceMsg (hsc_dflags hsc_env) 1 $
554 text "Warning: _result has been evaluated, some bindings have been lost"
556 new_ids <- zipWithM mkNewId occs filtered_ids
557 let names = map idName new_ids
559 -- make an Id for _result. We use the Unique of the FastString "_result";
560 -- we don't care about uniqueness here, because there will only be one
561 -- _result in scope at any time.
562 let result_name = mkInternalName (getUnique result_fs)
563 (mkVarOccFS result_fs) span
564 result_id = Id.mkGlobalId VanillaGlobal result_name result_ty
567 -- for each Id we're about to bind in the local envt:
568 -- - skolemise the type variables in its type, so they can't
569 -- be randomly unified with other types. These type variables
570 -- can only be resolved by type reconstruction in RtClosureInspect
571 -- - tidy the type variables
572 -- - globalise the Id (Ids are supposed to be Global, apparently).
574 let all_ids | isPointer result_id = result_id : new_ids
575 | otherwise = new_ids
576 (id_tys, tyvarss) = mapAndUnzip (skolemiseTy.idType) all_ids
577 (_,tidy_tys) = tidyOpenTypes emptyTidyEnv id_tys
578 new_tyvars = unionVarSets tyvarss
579 let final_ids = zipWith setIdType all_ids tidy_tys
580 ictxt0 = hsc_IC hsc_env
581 ictxt1 = extendInteractiveContext ictxt0 final_ids new_tyvars
582 Linker.extendLinkEnv [ (name,hval) | (name, Just hval) <- zip names mb_hValues ]
583 Linker.extendLinkEnv [(result_name, unsafeCoerce# apStack)]
584 hsc_env1 <- rttiEnvironment hsc_env{ hsc_IC = ictxt1 }
585 return (hsc_env1, result_name:names, span)
587 mkNewId :: OccName -> Id -> IO Id
589 us <- mkSplitUniqSupply 'I'
590 -- we need a fresh Unique for each Id we bind, because the linker
591 -- state is single-threaded and otherwise we'd spam old bindings
592 -- whenever we stop at a breakpoint. The InteractveContext is properly
593 -- saved/restored, but not the linker state. See #1743, test break026.
595 uniq = uniqFromSupply us
596 loc = nameSrcSpan (idName id)
597 name = mkInternalName uniq occ loc
599 new_id = Id.mkGlobalId VanillaGlobal name ty (idInfo id)
602 rttiEnvironment :: HscEnv -> IO HscEnv
603 rttiEnvironment hsc_env@HscEnv{hsc_IC=ic} = do
604 let InteractiveContext{ic_tmp_ids=tmp_ids} = ic
605 incompletelyTypedIds =
607 , not $ null [v | v <- varSetElems$ tyVarsOfType (idType id)
609 , (occNameFS.nameOccName.idName) id /= result_fs]
610 tys <- reconstructType hsc_env 10 `mapM` incompletelyTypedIds
611 -- map termType `fmap` (obtainTerm hsc_env False `mapM` incompletelyTypedIds)
613 let substs = [unifyRTTI ty ty'
614 | (ty, Just ty') <- zip (map idType incompletelyTypedIds) tys]
615 ic' = foldr (flip substInteractiveContext) ic
616 (map skolemiseSubst substs)
617 return hsc_env{hsc_IC=ic'}
619 skolemiseSubst subst = subst `setTvSubstEnv`
620 mapVarEnv (fst.skolemiseTy) (getTvSubstEnv subst)
622 skolemiseTy :: Type -> (Type, TyVarSet)
623 skolemiseTy ty = (substTy subst ty, mkVarSet new_tyvars)
624 where env = mkVarEnv (zip tyvars new_tyvar_tys)
625 subst = mkTvSubst emptyInScopeSet env
626 tyvars = varSetElems (tyVarsOfType ty)
627 new_tyvars = map skolemiseTyVar tyvars
628 new_tyvar_tys = map mkTyVarTy new_tyvars
630 skolemiseTyVar :: TyVar -> TyVar
631 skolemiseTyVar tyvar = mkTcTyVar (tyVarName tyvar) (tyVarKind tyvar)
632 (SkolemTv RuntimeUnkSkol)
634 getIdValFromApStack :: HValue -> Int -> IO (Maybe HValue)
635 getIdValFromApStack apStack (I# stackDepth) = do
636 case getApStackVal# apStack (stackDepth +# 1#) of
637 -- The +1 is magic! I don't know where it comes
638 -- from, but this makes things line up. --SDM
641 0# -> return Nothing -- AP_STACK not found
642 _ -> return (Just (unsafeCoerce# result))
644 pushResume :: HscEnv -> Resume -> HscEnv
645 pushResume hsc_env resume = hsc_env { hsc_IC = ictxt1 }
647 ictxt0 = hsc_IC hsc_env
648 ictxt1 = ictxt0 { ic_resume = resume : ic_resume ictxt0 }
650 -- -----------------------------------------------------------------------------
651 -- Abandoning a resume context
653 abandon :: Session -> IO Bool
654 abandon (Session ref) = do
655 hsc_env <- readIORef ref
656 let ic = hsc_IC hsc_env
657 resume = ic_resume ic
661 writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = rs } }
665 abandonAll :: Session -> IO Bool
666 abandonAll (Session ref) = do
667 hsc_env <- readIORef ref
668 let ic = hsc_IC hsc_env
669 resume = ic_resume ic
673 writeIORef ref hsc_env{ hsc_IC = ic { ic_resume = [] } }
677 -- when abandoning a computation we have to
678 -- (a) kill the thread with an async exception, so that the
679 -- computation itself is stopped, and
680 -- (b) fill in the MVar. This step is necessary because any
681 -- thunks that were under evaluation will now be updated
682 -- with the partial computation, which still ends in takeMVar,
683 -- so any attempt to evaluate one of these thunks will block
684 -- unless we fill in the MVar.
685 -- See test break010.
686 abandon_ :: Resume -> IO ()
688 killThread (resumeThreadId r)
689 putMVar (resumeBreakMVar r) ()
691 -- -----------------------------------------------------------------------------
692 -- Bounded list, optimised for repeated cons
694 data BoundedList a = BL
695 {-# UNPACK #-} !Int -- length
696 {-# UNPACK #-} !Int -- bound
698 [a] -- right, list is (left ++ reverse right)
700 nilBL :: Int -> BoundedList a
701 nilBL bound = BL 0 bound [] []
703 consBL a (BL len bound left right)
704 | len < bound = BL (len+1) bound (a:left) right
705 | null right = BL len bound [a] $! tail (reverse left)
706 | otherwise = BL len bound (a:left) $! tail right
708 toListBL (BL _ _ left right) = left ++ reverse right
710 fromListBL bound l = BL (length l) bound l []
712 -- lenBL (BL len _ _ _) = len
714 -- -----------------------------------------------------------------------------
715 -- | Set the interactive evaluation context.
717 -- Setting the context doesn't throw away any bindings; the bindings
718 -- we've built up in the InteractiveContext simply move to the new
719 -- module. They always shadow anything in scope in the current context.
720 setContext :: Session
721 -> [Module] -- entire top level scope of these modules
722 -> [Module] -- exports only of these modules
724 setContext sess@(Session ref) toplev_mods export_mods = do
725 hsc_env <- readIORef ref
726 let old_ic = hsc_IC hsc_env
727 hpt = hsc_HPT hsc_env
729 export_env <- mkExportEnv hsc_env export_mods
730 toplev_envs <- mapM (mkTopLevEnv hpt) toplev_mods
731 let all_env = foldr plusGlobalRdrEnv export_env toplev_envs
732 writeIORef ref hsc_env{ hsc_IC = old_ic { ic_toplev_scope = toplev_mods,
733 ic_exports = export_mods,
734 ic_rn_gbl_env = all_env }}
736 -- Make a GlobalRdrEnv based on the exports of the modules only.
737 mkExportEnv :: HscEnv -> [Module] -> IO GlobalRdrEnv
738 mkExportEnv hsc_env mods = do
739 stuff <- mapM (getModuleExports hsc_env) mods
741 (_msgs, mb_name_sets) = unzip stuff
742 gres = [ nameSetToGlobalRdrEnv (availsToNameSet avails) (moduleName mod)
743 | (Just avails, mod) <- zip mb_name_sets mods ]
745 return $! foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres
747 nameSetToGlobalRdrEnv :: NameSet -> ModuleName -> GlobalRdrEnv
748 nameSetToGlobalRdrEnv names mod =
749 mkGlobalRdrEnv [ GRE { gre_name = name, gre_par = NoParent, gre_prov = vanillaProv mod }
750 | name <- nameSetToList names ]
752 vanillaProv :: ModuleName -> Provenance
753 -- We're building a GlobalRdrEnv as if the user imported
754 -- all the specified modules into the global interactive module
755 vanillaProv mod_name = Imported [ImpSpec { is_decl = decl, is_item = ImpAll}]
757 decl = ImpDeclSpec { is_mod = mod_name, is_as = mod_name,
759 is_dloc = srcLocSpan interactiveSrcLoc }
761 mkTopLevEnv :: HomePackageTable -> Module -> IO GlobalRdrEnv
763 = case lookupUFM hpt (moduleName modl) of
764 Nothing -> throwDyn (ProgramError ("mkTopLevEnv: not a home module " ++
765 showSDoc (ppr modl)))
767 case mi_globals (hm_iface details) of
769 throwDyn (ProgramError ("mkTopLevEnv: not interpreted "
770 ++ showSDoc (ppr modl)))
771 Just env -> return env
773 -- | Get the interactive evaluation context, consisting of a pair of the
774 -- set of modules from which we take the full top-level scope, and the set
775 -- of modules from which we take just the exports respectively.
776 getContext :: Session -> IO ([Module],[Module])
777 getContext s = withSession s (\HscEnv{ hsc_IC=ic } ->
778 return (ic_toplev_scope ic, ic_exports ic))
780 -- | Returns 'True' if the specified module is interpreted, and hence has
781 -- its full top-level scope available.
782 moduleIsInterpreted :: Session -> Module -> IO Bool
783 moduleIsInterpreted s modl = withSession s $ \h ->
784 if modulePackageId modl /= thisPackage (hsc_dflags h)
786 else case lookupUFM (hsc_HPT h) (moduleName modl) of
787 Just details -> return (isJust (mi_globals (hm_iface details)))
788 _not_a_home_module -> return False
790 -- | Looks up an identifier in the current interactive context (for :info)
791 -- Filter the instances by the ones whose tycons (or clases resp)
792 -- are in scope (qualified or otherwise). Otherwise we list a whole lot too many!
793 -- The exact choice of which ones to show, and which to hide, is a judgement call.
795 getInfo :: Session -> Name -> IO (Maybe (TyThing,Fixity,[Instance]))
797 = withSession s $ \hsc_env ->
798 do { mb_stuff <- tcRnGetInfo hsc_env name
800 Nothing -> return Nothing
801 Just (thing, fixity, ispecs) -> do
802 { let rdr_env = ic_rn_gbl_env (hsc_IC hsc_env)
803 ; return (Just (thing, fixity, filter (plausible rdr_env) ispecs)) } }
805 plausible rdr_env ispec -- Dfun involving only names that are in ic_rn_glb_env
806 = all ok $ nameSetToList $ tyClsNamesOfType $ idType $ instanceDFunId ispec
807 where -- A name is ok if it's in the rdr_env,
808 -- whether qualified or not
809 ok n | n == name = True -- The one we looked for in the first place!
810 | isBuiltInSyntax n = True
811 | isExternalName n = any ((== n) . gre_name)
812 (lookupGRE_Name rdr_env n)
815 -- | Returns all names in scope in the current interactive context
816 getNamesInScope :: Session -> IO [Name]
817 getNamesInScope s = withSession s $ \hsc_env -> do
818 return (map gre_name (globalRdrEnvElts (ic_rn_gbl_env (hsc_IC hsc_env))))
820 getRdrNamesInScope :: Session -> IO [RdrName]
821 getRdrNamesInScope s = withSession s $ \hsc_env -> do
824 gbl_rdrenv = ic_rn_gbl_env ic
826 gbl_names = concat (map greToRdrNames (globalRdrEnvElts gbl_rdrenv))
827 lcl_names = map (mkRdrUnqual.nameOccName.idName) ids
829 return (gbl_names ++ lcl_names)
832 -- ToDo: move to RdrName
833 greToRdrNames :: GlobalRdrElt -> [RdrName]
834 greToRdrNames GRE{ gre_name = name, gre_prov = prov }
837 Imported specs -> concat (map do_spec (map is_decl specs))
839 occ = nameOccName name
842 | is_qual decl_spec = [qual]
843 | otherwise = [unqual,qual]
844 where qual = Qual (is_as decl_spec) occ
846 -- | Parses a string as an identifier, and returns the list of 'Name's that
847 -- the identifier can refer to in the current interactive context.
848 parseName :: Session -> String -> IO [Name]
849 parseName s str = withSession s $ \hsc_env -> do
850 maybe_rdr_name <- hscParseIdentifier (hsc_dflags hsc_env) str
851 case maybe_rdr_name of
853 Just (L _ rdr_name) -> do
854 mb_names <- tcRnLookupRdrName hsc_env rdr_name
858 -- ToDo: should return error messages
860 -- | Returns the 'TyThing' for a 'Name'. The 'Name' may refer to any
861 -- entity known to GHC, including 'Name's defined using 'runStmt'.
862 lookupName :: Session -> Name -> IO (Maybe TyThing)
863 lookupName s name = withSession s $ \hsc_env -> tcRnLookupName hsc_env name
865 -- -----------------------------------------------------------------------------
866 -- Getting the type of an expression
868 -- | Get the type of an expression
869 exprType :: Session -> String -> IO (Maybe Type)
870 exprType s expr = withSession s $ \hsc_env -> do
871 maybe_stuff <- hscTcExpr hsc_env expr
873 Nothing -> return Nothing
874 Just ty -> return (Just tidy_ty)
876 tidy_ty = tidyType emptyTidyEnv ty
878 -- -----------------------------------------------------------------------------
879 -- Getting the kind of a type
881 -- | Get the kind of a type
882 typeKind :: Session -> String -> IO (Maybe Kind)
883 typeKind s str = withSession s $ \hsc_env -> do
884 maybe_stuff <- hscKcType hsc_env str
886 Nothing -> return Nothing
887 Just kind -> return (Just kind)
889 -----------------------------------------------------------------------------
890 -- cmCompileExpr: compile an expression and deliver an HValue
892 compileExpr :: Session -> String -> IO (Maybe HValue)
893 compileExpr s expr = withSession s $ \hsc_env -> do
894 maybe_stuff <- hscStmt hsc_env ("let __cmCompileExpr = "++expr)
896 Nothing -> return Nothing
897 Just (ids, hval) -> do
899 hvals <- (unsafeCoerce# hval) :: IO [HValue]
902 ([n],[hv]) -> return (Just hv)
903 _ -> panic "compileExpr"
905 -- -----------------------------------------------------------------------------
906 -- Compile an expression into a dynamic
908 dynCompileExpr :: Session -> String -> IO (Maybe Dynamic)
909 dynCompileExpr ses expr = do
910 (full,exports) <- getContext ses
911 setContext ses full $
913 (stringToPackageId "base") (mkModuleName "Data.Dynamic")
915 let stmt = "let __dynCompileExpr = Data.Dynamic.toDyn (" ++ expr ++ ")"
916 res <- withSession ses (flip hscStmt stmt)
917 setContext ses full exports
919 Nothing -> return Nothing
920 Just (ids, hvals) -> do
921 vals <- (unsafeCoerce# hvals :: IO [Dynamic])
923 (_:[], v:[]) -> return (Just v)
924 _ -> panic "dynCompileExpr"
926 -----------------------------------------------------------------------------
927 -- show a module and it's source/object filenames
929 showModule :: Session -> ModSummary -> IO String
930 showModule s mod_summary = withSession s $ \hsc_env ->
931 isModuleInterpreted s mod_summary >>= \interpreted ->
932 return (showModMsg (hscTarget(hsc_dflags hsc_env)) interpreted mod_summary)
934 isModuleInterpreted :: Session -> ModSummary -> IO Bool
935 isModuleInterpreted s mod_summary = withSession s $ \hsc_env ->
936 case lookupUFM (hsc_HPT hsc_env) (ms_mod_name mod_summary) of
937 Nothing -> panic "missing linkable"
938 Just mod_info -> return (not obj_linkable)
940 obj_linkable = isObjectLinkable (expectJust "showModule" (hm_linkable mod_info))
942 ----------------------------------------------------------------------------
945 obtainTerm1 :: HscEnv -> Bool -> Maybe Type -> a -> IO Term
946 obtainTerm1 hsc_env force mb_ty x =
947 cvObtainTerm hsc_env maxBound force mb_ty (unsafeCoerce# x)
949 obtainTermB :: HscEnv -> Int -> Bool -> Id -> IO Term
950 obtainTermB hsc_env bound force id = do
951 hv <- Linker.getHValue hsc_env (varName id)
952 cvObtainTerm hsc_env bound force (Just$ idType id) hv
954 obtainTerm :: HscEnv -> Bool -> Id -> IO Term
955 obtainTerm hsc_env force id = do
956 hv <- Linker.getHValue hsc_env (varName id)
957 cvObtainTerm hsc_env maxBound force (Just$ idType id) hv
959 -- Uses RTTI to reconstruct the type of an Id, making it less polymorphic
960 reconstructType :: HscEnv -> Int -> Id -> IO (Maybe Type)
961 reconstructType hsc_env bound id = do
962 hv <- Linker.getHValue hsc_env (varName id)
963 cvReconstructType hsc_env bound (Just$ idType id) hv