1 -----------------------------------------------------------------------------
3 -- GHCi Interactive debugging commands
5 -- Pepe Iborra (supported by Google SoC) 2006
7 -- ToDo: lots of violation of layering here. This module should
8 -- decide whether it is above the GHC API (import GHC and nothing
11 -----------------------------------------------------------------------------
13 module Debugger (pprintClosureCommand) where
16 import RtClosureInspect
22 import Var hiding ( varName )
33 import Pretty ( Mode(..), showDocWith )
37 import Control.Exception
46 #include "HsVersions.h"
48 -------------------------------------
49 -- | The :print & friends commands
50 -------------------------------------
51 pprintClosureCommand :: Session -> Bool -> Bool -> String -> IO ()
52 pprintClosureCommand session bindThings force str = do
53 tythings <- (catMaybes . concat) `liftM`
54 mapM (\w -> GHC.parseName session w >>=
55 mapM (GHC.lookupName session))
57 substs <- catMaybes `liftM` mapM (go session)
58 [id | AnId id <- tythings]
59 mapM (applySubstToEnv session . skolemSubst) substs
63 -- Do the obtainTerm--bindSuspensions-computeSubstitution dance
64 go :: Session -> Id -> IO (Maybe TvSubst)
66 mb_term <- obtainTerm cms force id
67 maybe (return Nothing) `flip` mb_term $ \term_ -> do
68 term <- tidyTermTyVars cms term_
69 term' <- if not bindThings then return term
70 else bindSuspensions cms term
71 showterm <- printTerm cms term'
72 unqual <- GHC.getPrintUnqual cms
73 let showSDocForUserOneLine unqual doc =
74 showDocWith LeftMode (doc (mkErrStyle unqual))
75 (putStrLn . showSDocForUserOneLine unqual) (ppr id <+> char '=' <+> showterm)
76 -- Before leaving, we compare the type obtained to see if it's more specific
77 -- Then, we extract a substitution,
78 -- mapping the old tyvars to the reconstructed types.
79 let Just reconstructed_type = termType term
81 -- tcUnifyTys doesn't look through forall's, so we drop them from
82 -- the original type, instead of sigma-typing the reconstructed type
83 -- In addition, we strip newtypes too, since the reconstructed type might
84 -- not have recovered them all
85 mb_subst = tcUnifyTys (const BindMe)
86 [repType' $ dropForAlls$ idType id]
87 [repType' $ reconstructed_type]
89 ASSERT2 (isJust mb_subst, ppr reconstructed_type $$ (ppr$ idType id))
92 applySubstToEnv :: Session -> TvSubst -> IO ()
93 applySubstToEnv cms subst | isEmptyTvSubst subst = return ()
94 applySubstToEnv cms@(Session ref) subst = do
95 hsc_env <- readIORef ref
96 inScope <- GHC.getBindings cms
97 let ictxt = hsc_IC hsc_env
98 ids = ic_tmp_ids ictxt
99 ids' = map (\id -> id `setIdType` substTy subst (idType id)) ids
100 subst_dom= varEnvKeys$ getTvSubstEnv subst
101 subst_ran= varEnvElts$ getTvSubstEnv subst
102 new_tvs = [ tv | Just tv <- map getTyVar_maybe subst_ran]
103 ic_tyvars'= (`delVarSetListByKey` subst_dom)
104 . (`extendVarSetList` new_tvs)
106 ictxt' = ictxt { ic_tmp_ids = ids'
107 , ic_tyvars = ic_tyvars' }
108 writeIORef ref (hsc_env {hsc_IC = ictxt'})
110 where delVarSetListByKey = foldl' delVarSetByKey
112 tidyTermTyVars :: Session -> Term -> IO Term
113 tidyTermTyVars (Session ref) t = do
114 hsc_env <- readIORef ref
115 let env_tvs = ic_tyvars (hsc_IC hsc_env)
116 my_tvs = termTyVars t
117 tvs = env_tvs `minusVarSet` my_tvs
118 tyvarOccName = nameOccName . tyVarName
119 tidyEnv = (initTidyOccEnv (map tyvarOccName (varSetElems tvs))
120 , env_tvs `intersectVarSet` my_tvs)
121 return$ mapTermType (snd . tidyOpenType tidyEnv) t
123 -- | Give names, and bind in the interactive environment, to all the suspensions
124 -- included (inductively) in a term
125 bindSuspensions :: Session -> Term -> IO Term
126 bindSuspensions cms@(Session ref) t = do
127 hsc_env <- readIORef ref
128 inScope <- GHC.getBindings cms
129 let ictxt = hsc_IC hsc_env
131 alreadyUsedNames = map (occNameString . nameOccName . getName) inScope
132 availNames = map ((prefix++) . show) [1..] \\ alreadyUsedNames
133 availNames_var <- newIORef availNames
134 (t', stuff) <- foldTerm (nameSuspensionsAndGetInfos availNames_var) t
135 let (names, tys, hvals) = unzip3 stuff
136 let tys' = map mk_skol_ty tys
137 let ids = [ mkGlobalId VanillaGlobal name ty vanillaIdInfo
138 | (name,ty) <- zip names tys']
139 new_tyvars = tyVarsOfTypes tys'
140 new_ic = extendInteractiveContext ictxt ids new_tyvars
141 extendLinkEnv (zip names hvals)
142 writeIORef ref (hsc_env {hsc_IC = new_ic })
146 -- Processing suspensions. Give names and recopilate info
147 nameSuspensionsAndGetInfos :: IORef [String] -> TermFold (IO (Term, [(Name,Type,HValue)]))
148 nameSuspensionsAndGetInfos freeNames = TermFold
150 fSuspension = doSuspension freeNames
151 , fTerm = \ty dc v tt -> do
153 let (terms,names) = unzip tt'
154 return (Term ty dc v terms, concat names)
155 , fPrim = \ty n ->return (Prim ty n,[])
157 doSuspension freeNames ct mb_ty hval Nothing = do
158 name <- atomicModifyIORef freeNames (\x->(tail x, head x))
159 n <- newGrimName cms name
160 let ty' = fromMaybe (error "unexpected") mb_ty
161 return (Suspension ct mb_ty hval (Just n), [(n,ty',hval)])
164 -- A custom Term printer to enable the use of Show instances
165 printTerm cms@(Session ref) = cPprTerm cPpr
167 cPpr = \p-> cPprShowable : cPprTermBase p
168 cPprShowable prec t@Term{ty=ty, dc=dc, val=val} = do
169 let hasType = isEmptyVarSet (tyVarsOfType ty) -- redundant
170 isEvaled = isFullyEvaluatedTerm t
171 if not isEvaled -- || not hasType
174 hsc_env <- readIORef ref
175 dflags <- GHC.getSessionDynFlags cms
177 (new_env, bname) <- bindToFreshName hsc_env ty "showme"
178 writeIORef ref (new_env)
179 let noop_log _ _ _ _ = return ()
180 expr = "show " ++ showSDoc (ppr bname)
181 GHC.setSessionDynFlags cms dflags{log_action=noop_log}
182 mb_txt <- withExtendedLinkEnv [(bname, val)]
183 (GHC.compileExpr cms expr)
184 let myprec = 9 -- TODO Infix constructors
186 Just txt -> return . Just . text . unsafeCoerce#
188 Nothing -> return Nothing
190 writeIORef ref hsc_env
191 GHC.setSessionDynFlags cms dflags
193 bindToFreshName hsc_env ty userName = do
194 name <- newGrimName cms userName
195 let ictxt = hsc_IC hsc_env
196 tmp_ids = ic_tmp_ids ictxt
197 id = mkGlobalId VanillaGlobal name ty vanillaIdInfo
198 new_ic = ictxt { ic_tmp_ids = id : tmp_ids }
199 return (hsc_env {hsc_IC = new_ic }, name)
201 -- Create new uniques and give them sequentially numbered names
202 -- newGrimName :: Session -> String -> IO Name
203 newGrimName cms userName = do
204 us <- mkSplitUniqSupply 'b'
205 let unique = uniqFromSupply us
206 occname = mkOccName varName userName
207 name = mkInternalName unique occname noSrcLoc
210 skolemSubst subst = subst `setTvSubstEnv`
211 mapVarEnv mk_skol_ty (getTvSubstEnv subst)
212 mk_skol_ty ty | tyvars <- varSetElems (tyVarsOfType ty)
213 , tyvars' <- map (mkTyVarTy . mk_skol_tv) tyvars
214 = substTyWith tyvars tyvars' ty
215 mk_skol_tv tv = mkTcTyVar (tyVarName tv) (tyVarKind tv)
216 (SkolemTv RuntimeUnkSkol)