----------------------------------------------------------------------------- -- -- GHCi Interactive debugging commands -- -- Pepe Iborra (supported by Google SoC) 2006 -- -- ToDo: lots of violation of layering here. This module should -- decide whether it is above the GHC API (import GHC and nothing -- else) or below it. -- ----------------------------------------------------------------------------- module Debugger (pprintClosureCommand, showTerm, pprTypeAndContents) where import Linker import RtClosureInspect import GhcMonad import HscTypes import Id import Name import Var hiding ( varName ) import VarSet import UniqSupply import Type import Kind import GHC import Outputable import PprTyThing import MonadUtils import DynFlags import Exception import Control.Monad import Data.List import Data.Maybe import Data.IORef import GHC.Exts ------------------------------------- -- | The :print & friends commands ------------------------------------- pprintClosureCommand :: GhcMonad m => Bool -> Bool -> String -> m () pprintClosureCommand bindThings force str = do tythings <- (catMaybes . concat) `liftM` mapM (\w -> GHC.parseName w >>= mapM GHC.lookupName) (words str) let ids = [id | AnId id <- tythings] -- Obtain the terms and the recovered type information (subst, terms) <- mapAccumLM go emptyTvSubst ids -- Apply the substitutions obtained after recovering the types modifySession $ \hsc_env -> hsc_env{hsc_IC = substInteractiveContext (hsc_IC hsc_env) subst} -- Finally, print the Terms unqual <- GHC.getPrintUnqual docterms <- mapM showTerm terms dflags <- getDynFlags liftIO $ (printOutputForUser dflags unqual . vcat) (zipWith (\id docterm -> ppr id <+> char '=' <+> docterm) ids docterms) where -- Do the obtainTerm--bindSuspensions-computeSubstitution dance go :: GhcMonad m => TvSubst -> Id -> m (TvSubst, Term) go subst id = do let id' = id `setIdType` substTy subst (idType id) term_ <- GHC.obtainTermFromId maxBound force id' term <- tidyTermTyVars term_ term' <- if bindThings && False == isUnliftedTypeKind (termType term) then bindSuspensions term else return term -- Before leaving, we compare the type obtained to see if it's more specific -- Then, we extract a substitution, -- mapping the old tyvars to the reconstructed types. let reconstructed_type = termType term hsc_env <- getSession case (improveRTTIType hsc_env (idType id) (reconstructed_type)) of Nothing -> return (subst, term') Just subst' -> do { traceOptIf Opt_D_dump_rtti (fsep $ [text "RTTI Improvement for", ppr id, text "is the substitution:" , ppr subst']) ; return (subst `unionTvSubst` subst', term')} tidyTermTyVars :: GhcMonad m => Term -> m Term tidyTermTyVars t = withSession $ \hsc_env -> do let env_tvs = tyThingsTyVars $ ic_tythings $ hsc_IC hsc_env my_tvs = termTyVars t tvs = env_tvs `minusVarSet` my_tvs tyvarOccName = nameOccName . tyVarName tidyEnv = (initTidyOccEnv (map tyvarOccName (varSetElems tvs)) , env_tvs `intersectVarSet` my_tvs) return$ mapTermType (snd . tidyOpenType tidyEnv) t -- | Give names, and bind in the interactive environment, to all the suspensions -- included (inductively) in a term bindSuspensions :: GhcMonad m => Term -> m Term bindSuspensions t = do hsc_env <- getSession inScope <- GHC.getBindings let ictxt = hsc_IC hsc_env prefix = "_t" alreadyUsedNames = map (occNameString . nameOccName . getName) inScope availNames = map ((prefix++) . show) [(1::Int)..] \\ alreadyUsedNames availNames_var <- liftIO $ newIORef availNames (t', stuff) <- liftIO $ foldTerm (nameSuspensionsAndGetInfos availNames_var) t let (names, tys, hvals) = unzip3 stuff let ids = [ mkVanillaGlobal name ty | (name,ty) <- zip names tys] new_ic = extendInteractiveContext ictxt (map AnId ids) liftIO $ extendLinkEnv (zip names hvals) modifySession $ \_ -> hsc_env {hsc_IC = new_ic } return t' where -- Processing suspensions. Give names and recopilate info nameSuspensionsAndGetInfos :: IORef [String] -> TermFold (IO (Term, [(Name,Type,HValue)])) nameSuspensionsAndGetInfos freeNames = TermFold { fSuspension = doSuspension freeNames , fTerm = \ty dc v tt -> do tt' <- sequence tt let (terms,names) = unzip tt' return (Term ty dc v terms, concat names) , fPrim = \ty n ->return (Prim ty n,[]) , fNewtypeWrap = \ty dc t -> do (term, names) <- t return (NewtypeWrap ty dc term, names) , fRefWrap = \ty t -> do (term, names) <- t return (RefWrap ty term, names) } doSuspension freeNames ct ty hval _name = do name <- atomicModifyIORef freeNames (\x->(tail x, head x)) n <- newGrimName name return (Suspension ct ty hval (Just n), [(n,ty,hval)]) -- A custom Term printer to enable the use of Show instances showTerm :: GhcMonad m => Term -> m SDoc showTerm term = do dflags <- GHC.getSessionDynFlags if gopt Opt_PrintEvldWithShow dflags then cPprTerm (liftM2 (++) (\_y->[cPprShowable]) cPprTermBase) term else cPprTerm cPprTermBase term where cPprShowable prec t@Term{ty=ty, val=val} = if not (isFullyEvaluatedTerm t) then return Nothing else do hsc_env <- getSession dflags <- GHC.getSessionDynFlags do (new_env, bname) <- bindToFreshName hsc_env ty "showme" setSession new_env -- XXX: this tries to disable logging of errors -- does this still do what it is intended to do -- with the changed error handling and logging? let noop_log _ _ _ _ _ = return () expr = "show " ++ showPpr dflags bname _ <- GHC.setSessionDynFlags dflags{log_action=noop_log} txt_ <- withExtendedLinkEnv [(bname, val)] (GHC.compileExpr expr) let myprec = 10 -- application precedence. TODO Infix constructors let txt = unsafeCoerce# txt_ if not (null txt) then return $ Just $ cparen (prec >= myprec && needsParens txt) (text txt) else return Nothing `gfinally` do setSession hsc_env GHC.setSessionDynFlags dflags cPprShowable prec NewtypeWrap{ty=new_ty,wrapped_term=t} = cPprShowable prec t{ty=new_ty} cPprShowable _ _ = return Nothing needsParens ('"':_) = False -- some simple heuristics to see whether parens -- are redundant in an arbitrary Show output needsParens ('(':_) = False needsParens txt = ' ' `elem` txt bindToFreshName hsc_env ty userName = do name <- newGrimName userName let id = AnId $ mkVanillaGlobal name ty new_ic = extendInteractiveContext (hsc_IC hsc_env) [id] return (hsc_env {hsc_IC = new_ic }, name) -- Create new uniques and give them sequentially numbered names newGrimName :: MonadIO m => String -> m Name newGrimName userName = do us <- liftIO $ mkSplitUniqSupply 'b' let unique = uniqFromSupply us occname = mkOccName varName userName name = mkInternalName unique occname noSrcSpan return name pprTypeAndContents :: GhcMonad m => Id -> m SDoc pprTypeAndContents id = do dflags <- GHC.getSessionDynFlags let pcontents = gopt Opt_PrintBindContents dflags pprdId = (PprTyThing.pprTyThing . AnId) id if pcontents then do let depthBound = 100 -- If the value is an exception, make sure we catch it and -- show the exception, rather than propagating the exception out. e_term <- gtry $ GHC.obtainTermFromId depthBound False id docs_term <- case e_term of Right term -> showTerm term Left exn -> return (text "*** Exception:" <+> text (show (exn :: SomeException))) return $ pprdId <+> equals <+> docs_term else return pprdId -------------------------------------------------------------- -- Utils traceOptIf :: GhcMonad m => DumpFlag -> SDoc -> m () traceOptIf flag doc = do dflags <- GHC.getSessionDynFlags when (dopt flag dflags) $ liftIO $ printInfoForUser dflags alwaysQualify doc