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 type_env = ic_type_env ictxt
99 ids = typeEnvIds type_env
100 ids' = map (\id -> id `setIdType` substTy subst (idType id)) ids
101 type_env'= extendTypeEnvWithIds type_env ids'
102 ictxt' = ictxt { ic_type_env = type_env' }
103 writeIORef ref (hsc_env {hsc_IC = ictxt'})
105 tidyTermTyVars :: Session -> Term -> IO Term
106 tidyTermTyVars (Session ref) t = do
107 hsc_env <- readIORef ref
108 let env_tvs = ic_tyvars (hsc_IC hsc_env)
109 my_tvs = termTyVars t
110 tvs = env_tvs `minusVarSet` my_tvs
111 tyvarOccName = nameOccName . tyVarName
112 tidyEnv = (initTidyOccEnv (map tyvarOccName (varSetElems tvs))
113 , env_tvs `intersectVarSet` my_tvs)
114 return$ mapTermType (snd . tidyOpenType tidyEnv) t
116 -- | Give names, and bind in the interactive environment, to all the suspensions
117 -- included (inductively) in a term
118 bindSuspensions :: Session -> Term -> IO Term
119 bindSuspensions cms@(Session ref) t = do
120 hsc_env <- readIORef ref
121 inScope <- GHC.getBindings cms
122 let ictxt = hsc_IC hsc_env
123 type_env = ic_type_env ictxt
125 alreadyUsedNames = map (occNameString . nameOccName . getName) inScope
126 availNames = map ((prefix++) . show) [1..] \\ alreadyUsedNames
127 availNames_var <- newIORef availNames
128 (t', stuff) <- foldTerm (nameSuspensionsAndGetInfos availNames_var) t
129 let (names, tys, hvals) = unzip3 stuff
130 let tys' = map mk_skol_ty tys
131 let ids = [ mkGlobalId VanillaGlobal name ty vanillaIdInfo
132 | (name,ty) <- zip names tys']
133 new_tyvars = tyVarsOfTypes tys'
134 new_type_env = extendTypeEnvWithIds type_env ids
135 old_tyvars = ic_tyvars ictxt
136 new_ic = ictxt { ic_type_env = new_type_env,
137 ic_tyvars = old_tyvars `unionVarSet` new_tyvars }
138 extendLinkEnv (zip names hvals)
139 writeIORef ref (hsc_env {hsc_IC = new_ic })
143 -- Processing suspensions. Give names and recopilate info
144 nameSuspensionsAndGetInfos :: IORef [String] -> TermFold (IO (Term, [(Name,Type,HValue)]))
145 nameSuspensionsAndGetInfos freeNames = TermFold
147 fSuspension = doSuspension freeNames
148 , fTerm = \ty dc v tt -> do
150 let (terms,names) = unzip tt'
151 return (Term ty dc v terms, concat names)
152 , fPrim = \ty n ->return (Prim ty n,[])
154 doSuspension freeNames ct mb_ty hval Nothing = do
155 name <- atomicModifyIORef freeNames (\x->(tail x, head x))
156 n <- newGrimName cms name
157 let ty' = fromMaybe (error "unexpected") mb_ty
158 return (Suspension ct mb_ty hval (Just n), [(n,ty',hval)])
161 -- A custom Term printer to enable the use of Show instances
162 printTerm cms@(Session ref) = cPprTerm cPpr
164 cPpr = \p-> cPprShowable : cPprTermBase p
165 cPprShowable prec t@Term{ty=ty, dc=dc, val=val} = do
166 let hasType = isEmptyVarSet (tyVarsOfType ty) -- redundant
167 isEvaled = isFullyEvaluatedTerm t
168 if not isEvaled -- || not hasType
171 hsc_env <- readIORef ref
172 dflags <- GHC.getSessionDynFlags cms
174 (new_env, bname) <- bindToFreshName hsc_env ty "showme"
175 writeIORef ref (new_env)
176 let noop_log _ _ _ _ = return ()
177 expr = "show " ++ showSDoc (ppr bname)
178 GHC.setSessionDynFlags cms dflags{log_action=noop_log}
179 mb_txt <- withExtendedLinkEnv [(bname, val)]
180 (GHC.compileExpr cms expr)
181 let myprec = 9 -- TODO Infix constructors
183 Just txt -> return . Just . text . unsafeCoerce#
185 Nothing -> return Nothing
187 writeIORef ref hsc_env
188 GHC.setSessionDynFlags cms dflags
190 bindToFreshName hsc_env ty userName = do
191 name <- newGrimName cms userName
192 let ictxt = hsc_IC hsc_env
193 type_env = ic_type_env ictxt
194 id = mkGlobalId VanillaGlobal name ty vanillaIdInfo
195 new_type_env = extendTypeEnv type_env (AnId id)
196 new_ic = ictxt { ic_type_env = new_type_env }
197 return (hsc_env {hsc_IC = new_ic }, name)
199 -- Create new uniques and give them sequentially numbered names
200 -- newGrimName :: Session -> String -> IO Name
201 newGrimName cms userName = do
202 us <- mkSplitUniqSupply 'b'
203 let unique = uniqFromSupply us
204 occname = mkOccName varName userName
205 name = mkInternalName unique occname noSrcLoc
208 skolemSubst subst = subst `setTvSubstEnv`
209 mapVarEnv mk_skol_ty (getTvSubstEnv subst)
210 mk_skol_ty ty | tyvars <- varSetElems (tyVarsOfType ty)
211 , tyvars' <- map (mkTyVarTy . mk_skol_tv) tyvars
212 = substTyWith tyvars tyvars' ty
213 mk_skol_tv tv = mkTcTyVar (tyVarName tv) (tyVarKind tv)
214 (SkolemTv RuntimeUnkSkol)