------------------------------------------------------------------------------\r
---\r
--- GHC Interactive support for inspecting arbitrary closures at runtime\r
---\r
--- Pepe Iborra (supported by Google SoC) 2006\r
---\r
------------------------------------------------------------------------------\r
-\r
-module RtClosureInspect(\r
- \r
- cvObtainTerm, -- :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term\r
-\r
- AddressEnv(..), \r
- DataConEnv,\r
- extendAddressEnvList, \r
- elemAddressEnv, \r
- delFromAddressEnv, \r
- emptyAddressEnv, \r
- lookupAddressEnv, \r
-\r
- ClosureType(..), \r
- getClosureData, \r
- Closure ( tipe, infoTable, ptrs, nonPtrs ), \r
- getClosureType, \r
- isConstr, \r
- isIndirection,\r
- getInfoTablePtr, \r
-\r
- Term(..), \r
- printTerm, \r
- customPrintTerm, \r
- customPrintTermBase,\r
- termType,\r
- foldTerm, \r
- TermFold(..), \r
- idTermFold, \r
- idTermFoldM,\r
- isFullyEvaluated, \r
- isPointed,\r
- isFullyEvaluatedTerm,\r
--- unsafeDeepSeq, \r
- ) where \r
-\r
-#include "HsVersions.h"\r
-\r
-import ByteCodeItbls ( StgInfoTable )\r
-import qualified ByteCodeItbls as BCI( StgInfoTable(..) )\r
-import ByteCodeLink ( HValue )\r
-import HscTypes ( HscEnv )\r
-\r
-import DataCon \r
-import Type \r
-import TcRnMonad\r
-import TcType\r
-import TcMType\r
-import TcUnify\r
-import TcGadt\r
-import DriverPhases\r
-import TyCon \r
-import Var\r
-import Name \r
-import Unique\r
-import UniqSupply\r
-import Var ( setVarUnique, mkTyVar, tyVarKind, setTyVarKind )\r
-import VarEnv ( mkVarEnv )\r
-import OccName ( emptyTidyOccEnv )\r
-import VarSet ( VarSet, mkVarSet, varSetElems, unionVarSets )\r
-import Unique ( getUnique, incrUnique )\r
-import {-#SOURCE#-} TcRnDriver ( tcRnRecoverDataCon )\r
-\r
-import TysPrim \r
-import PrelNames\r
-import TysWiredIn\r
-\r
-import Constants ( wORD_SIZE )\r
-import FastString ( mkFastString )\r
-import Outputable\r
-import Maybes\r
-import Panic\r
-import FiniteMap\r
-\r
-import GHC.Arr ( Array(..) )\r
-import GHC.Ptr ( Ptr(..), castPtr )\r
-import GHC.Exts \r
-import GHC.Int ( Int32(..), Int64(..) )\r
-import GHC.Word ( Word32(..), Word64(..) )\r
-\r
-import Control.Monad ( liftM, liftM2, msum )\r
-import Data.Maybe\r
-import Data.Array.Base\r
-import Data.List ( partition )\r
-import Foreign.Storable\r
-import Foreign ( unsafePerformIO )\r
-\r
----------------------------------------------\r
--- * A representation of semi evaluated Terms\r
----------------------------------------------\r
-{-\r
- A few examples in this representation:\r
-\r
- > Just 10 = Term Data.Maybe Data.Maybe.Just (Just 10) [Term Int I# (10) "10"]\r
-\r
- > (('a',_,_),_,('b',_,_)) = \r
- Term ((Char,b,c),d,(Char,e,f)) (,,) (('a',_,_),_,('b',_,_))\r
- [ Term (Char, b, c) (,,) ('a',_,_) [Term Char C# "a", Thunk, Thunk]\r
- , Thunk\r
- , Term (Char, e, f) (,,) ('b',_,_) [Term Char C# "b", Thunk, Thunk]]\r
--}\r
-\r
-data Term = Term { ty :: Type \r
- , dc :: DataCon \r
- , val :: HValue \r
- , subTerms :: [Term] }\r
-\r
- | Prim { ty :: Type\r
- , value :: String }\r
-\r
- | Suspension { ctype :: ClosureType\r
- , mb_ty :: Maybe Type\r
- , val :: HValue\r
- , bound_to :: Maybe Name -- Useful for printing\r
- }\r
-\r
-isTerm Term{} = True\r
-isTerm _ = False\r
-isSuspension Suspension{} = True\r
-isSuspension _ = False\r
-isPrim Prim{} = True\r
-isPrim _ = False\r
-\r
-termType t@(Suspension {}) = mb_ty t\r
-termType t = Just$ ty t\r
-\r
-instance Outputable (Term) where\r
- ppr = head . customPrintTerm customPrintTermBase\r
-\r
--------------------------------------------------------------------------\r
--- Runtime Closure Datatype and functions for retrieving closure related stuff\r
--------------------------------------------------------------------------\r
-data ClosureType = Constr \r
- | Fun \r
- | Thunk Int \r
- | ThunkSelector\r
- | Blackhole \r
- | AP \r
- | PAP \r
- | Indirection Int \r
- | Other Int\r
- deriving (Show, Eq)\r
-\r
-data Closure = Closure { tipe :: ClosureType \r
- , infoTable :: StgInfoTable\r
- , ptrs :: Array Int HValue\r
- -- What would be the type here? HValue is ok? Should I build a Ptr?\r
- , nonPtrs :: ByteArray# \r
- }\r
-\r
-instance Outputable ClosureType where\r
- ppr = text . show \r
-\r
-getInfoTablePtr :: a -> Ptr StgInfoTable\r
-getInfoTablePtr x = \r
- case infoPtr# x of\r
- itbl_ptr -> castPtr ( Ptr itbl_ptr )\r
-\r
-getClosureType :: a -> IO ClosureType\r
-getClosureType = liftM (readCType . BCI.tipe ) . peek . getInfoTablePtr\r
-\r
-#include "../includes/ClosureTypes.h"\r
-\r
-aP_CODE = AP\r
-pAP_CODE = PAP\r
-#undef AP\r
-#undef PAP\r
-\r
-getClosureData :: a -> IO Closure\r
-getClosureData a = do\r
- itbl <- peek (getInfoTablePtr a)\r
- let tipe = readCType (BCI.tipe itbl)\r
- case closurePayload# a of \r
- (# ptrs, nptrs #) -> \r
- let elems = BCI.ptrs itbl \r
- ptrsList = Array 0 (fromIntegral$ elems) ptrs\r
- in ptrsList `seq` return (Closure tipe itbl ptrsList nptrs)\r
-\r
-readCType :: Integral a => a -> ClosureType\r
-readCType i\r
- | i >= CONSTR && i <= CONSTR_NOCAF_STATIC = Constr\r
- | i >= FUN && i <= FUN_STATIC = Fun\r
- | i >= THUNK && i < THUNK_SELECTOR = Thunk (fromIntegral i)\r
- | i == THUNK_SELECTOR = ThunkSelector\r
- | i == BLACKHOLE = Blackhole\r
- | i >= IND && i <= IND_STATIC = Indirection (fromIntegral i)\r
- | fromIntegral i == aP_CODE = AP\r
- | fromIntegral i == pAP_CODE = PAP\r
- | otherwise = Other (fromIntegral i)\r
-\r
-isConstr, isIndirection :: ClosureType -> Bool\r
-isConstr Constr = True\r
-isConstr _ = False\r
-\r
-isIndirection (Indirection _) = True\r
---isIndirection ThunkSelector = True\r
-isIndirection _ = False\r
-\r
-isFullyEvaluated :: a -> IO Bool\r
-isFullyEvaluated a = do \r
- closure <- getClosureData a \r
- case tipe closure of\r
- Constr -> do are_subs_evaluated <- amapM isFullyEvaluated (ptrs closure)\r
- return$ and are_subs_evaluated\r
- otherwise -> return False\r
- where amapM f = sequence . amap' f\r
-\r
-amap' f (Array i0 i arr#) = map (\(I# i#) -> case indexArray# arr# i# of\r
- (# e #) -> f e)\r
- [0 .. i - i0]\r
-\r
--- TODO: Fix it. Probably the otherwise case is failing, trace/debug it\r
-{-\r
-unsafeDeepSeq :: a -> b -> b\r
-unsafeDeepSeq = unsafeDeepSeq1 2\r
- where unsafeDeepSeq1 0 a b = seq a $! b\r
- unsafeDeepSeq1 i a b -- 1st case avoids infinite loops for non reducible thunks\r
- | not (isConstr tipe) = seq a $! unsafeDeepSeq1 (i-1) a b \r
- -- | unsafePerformIO (isFullyEvaluated a) = b\r
- | otherwise = case unsafePerformIO (getClosureData a) of\r
- closure -> foldl' (flip unsafeDeepSeq) b (ptrs closure)\r
- where tipe = unsafePerformIO (getClosureType a)\r
--}\r
-isPointed :: Type -> Bool\r
-isPointed t | Just (t, _) <- splitTyConApp_maybe t = not$ isUnliftedTypeKind (tyConKind t)\r
-isPointed _ = True\r
-\r
-#define MKDECODER(offset,cons,builder) (offset, show$ cons (builder addr 0#))\r
-\r
-extractUnboxed :: [Type] -> ByteArray# -> [String]\r
-extractUnboxed tt ba = helper tt (byteArrayContents# ba)\r
- where helper :: [Type] -> Addr# -> [String]\r
- helper (t:tt) addr \r
- | Just ( tycon,_) <- splitTyConApp_maybe t \r
- = let (offset, txt) = decode tycon addr\r
- (I# word_offset) = offset*wORD_SIZE\r
- in txt : helper tt (plusAddr# addr word_offset)\r
- | otherwise \r
- = -- ["extractUnboxed.helper: Urk. I got a " ++ showSDoc (ppr t)]\r
- panic$ "extractUnboxed.helper: Urk. I got a " ++ showSDoc (ppr t)\r
- helper [] addr = []\r
- decode :: TyCon -> Addr# -> (Int, String)\r
- decode t addr \r
- | t == charPrimTyCon = MKDECODER(1,C#,indexCharOffAddr#)\r
- | t == intPrimTyCon = MKDECODER(1,I#,indexIntOffAddr#)\r
- | t == wordPrimTyCon = MKDECODER(1,W#,indexWordOffAddr#)\r
- | t == floatPrimTyCon = MKDECODER(1,F#,indexFloatOffAddr#)\r
- | t == doublePrimTyCon = MKDECODER(2,D#,indexDoubleOffAddr#)\r
- | t == int32PrimTyCon = MKDECODER(1,I32#,indexInt32OffAddr#)\r
- | t == word32PrimTyCon = MKDECODER(1,W32#,indexWord32OffAddr#)\r
- | t == int64PrimTyCon = MKDECODER(2,I64#,indexInt64OffAddr#)\r
- | t == word64PrimTyCon = MKDECODER(2,W64#,indexWord64OffAddr#)\r
- | t == addrPrimTyCon = MKDECODER(1,I#,(\x off-> addr2Int# (indexAddrOffAddr# x off))) --OPT Improve the presentation of addresses\r
- | t == stablePtrPrimTyCon = (1, "<stablePtr>")\r
- | t == stableNamePrimTyCon = (1, "<stableName>")\r
- | t == statePrimTyCon = (1, "<statethread>")\r
- | t == realWorldTyCon = (1, "<realworld>")\r
- | t == threadIdPrimTyCon = (1, "<ThreadId>")\r
- | t == weakPrimTyCon = (1, "<Weak>")\r
- | t == arrayPrimTyCon = (1,"<array>")\r
- | t == byteArrayPrimTyCon = (1,"<bytearray>")\r
- | t == mutableArrayPrimTyCon = (1, "<mutableArray>")\r
- | t == mutableByteArrayPrimTyCon = (1, "<mutableByteArray>")\r
- | t == mutVarPrimTyCon= (1, "<mutVar>")\r
- | t == mVarPrimTyCon = (1, "<mVar>")\r
- | t == tVarPrimTyCon = (1, "<tVar>")\r
- | otherwise = (1, showSDoc (char '<' <> ppr t <> char '>')) \r
- -- We cannot know the right offset in the otherwise case, so 1 is just a wild dangerous guess!\r
- -- TODO: Improve the offset handling in decode (make it machine dependant)\r
-\r
------------------------------------\r
--- Boilerplate Fold code for Term\r
------------------------------------\r
-\r
-data TermFold a = TermFold { fTerm :: Type -> DataCon -> HValue -> [a] -> a\r
- , fPrim :: Type -> String -> a\r
- , fSuspension :: ClosureType -> Maybe Type -> HValue -> Maybe Name -> a\r
- }\r
-\r
-foldTerm :: TermFold a -> Term -> a\r
-foldTerm tf (Term ty dc v tt) = fTerm tf ty dc v (map (foldTerm tf) tt)\r
-foldTerm tf (Prim ty v ) = fPrim tf ty v\r
-foldTerm tf (Suspension ct ty v b) = fSuspension tf ct ty v b\r
-\r
-idTermFold :: TermFold Term\r
-idTermFold = TermFold {\r
- fTerm = Term,\r
- fPrim = Prim,\r
- fSuspension = Suspension\r
- }\r
-idTermFoldM :: Monad m => TermFold (m Term)\r
-idTermFoldM = TermFold {\r
- fTerm = \ty dc v tt -> sequence tt >>= return . Term ty dc v,\r
- fPrim = (return.). Prim,\r
- fSuspension = (((return.).).). Suspension\r
- }\r
-\r
-----------------------------------\r
--- Pretty printing of terms\r
-----------------------------------\r
-\r
-parensCond True = parens\r
-parensCond False = id\r
-app_prec::Int\r
-app_prec = 10\r
-\r
-printTerm :: Term -> SDoc\r
-printTerm Prim{value=value} = text value \r
-printTerm t@Term{} = printTerm1 0 t \r
-printTerm Suspension{bound_to=Nothing} = char '_' -- <> ppr ct <> char '_'\r
-printTerm Suspension{mb_ty=Just ty, bound_to=Just n} =\r
- parens$ ppr n <> text "::" <> ppr ty \r
-\r
-printTerm1 p Term{dc=dc, subTerms=tt} \r
-{- | dataConIsInfix dc, (t1:t2:tt') <- tt \r
- = parens (printTerm1 True t1 <+> ppr dc <+> printTerm1 True ppr t2) \r
- <+> hsep (map (printTerm1 True) tt) \r
--}\r
- | null tt = ppr dc\r
- | otherwise = parensCond (p > app_prec) \r
- (ppr dc <+> sep (map (printTerm1 (app_prec+1)) tt))\r
-\r
- where fixity = undefined \r
-\r
-printTerm1 _ t = printTerm t\r
-\r
-customPrintTerm :: Monad m => ((Int->Term->m SDoc)->[Term->m (Maybe SDoc)]) -> Term -> m SDoc\r
-customPrintTerm custom = let \r
--- go :: Monad m => Int -> Term -> m SDoc\r
- go prec t@Term{subTerms=tt, dc=dc} = do\r
- mb_customDocs <- sequence$ sequence (custom go) t -- Inner sequence is List monad\r
- case msum mb_customDocs of -- msum is in Maybe monad\r
- Just doc -> return$ parensCond (prec>app_prec+1) doc\r
--- | dataConIsInfix dc, (t1:t2:tt') <- tt =\r
- Nothing -> do pprSubterms <- mapM (go (app_prec+1)) tt\r
- return$ parensCond (prec>app_prec+1) \r
- (ppr dc <+> sep pprSubterms)\r
- go _ t = return$ printTerm t\r
- in go 0 \r
- where fixity = undefined \r
-\r
-customPrintTermBase :: Monad m => (Int->Term-> m SDoc)->[Term->m (Maybe SDoc)]\r
-customPrintTermBase showP =\r
- [ \r
- test isTupleDC (liftM (parens . cat . punctuate comma) . mapM (showP 0) . subTerms)\r
- , test (isDC consDataCon) (\Term{subTerms=[h,t]} -> doList h t)\r
- , test (isDC intDataCon) (coerceShow$ \(a::Int)->a)\r
- , test (isDC charDataCon) (coerceShow$ \(a::Char)->a)\r
--- , test (isDC wordDataCon) (coerceShow$ \(a::Word)->a)\r
- , test (isDC floatDataCon) (coerceShow$ \(a::Float)->a)\r
- , test (isDC doubleDataCon) (coerceShow$ \(a::Double)->a)\r
- , test isIntegerDC (coerceShow$ \(a::Integer)->a)\r
- ] \r
- where test pred f t = if pred t then liftM Just (f t) else return Nothing\r
- isIntegerDC Term{dc=dc} = \r
- dataConName dc `elem` [ smallIntegerDataConName\r
- , largeIntegerDataConName] \r
- isTupleDC Term{dc=dc} = dc `elem` snd (unzip (elems boxedTupleArr))\r
- isDC a_dc Term{dc=dc} = a_dc == dc\r
- coerceShow f Term{val=val} = return . text . show . f . unsafeCoerce# $ val\r
- --TODO pprinting of list terms is not lazy\r
- doList h t = do\r
- let elems = h : getListTerms t\r
- isConsLast = isSuspension (last elems) && \r
- (mb_ty$ last elems) /= (termType h)\r
- init <- mapM (showP 0) (init elems) \r
- last0 <- showP 0 (last elems)\r
- let last = case length elems of \r
- 1 -> last0 \r
- _ | isConsLast -> text " | " <> last0\r
- _ -> comma <> last0\r
- return$ brackets (cat (punctuate comma init ++ [last]))\r
-\r
- where Just a /= Just b = not (a `coreEqType` b)\r
- _ /= _ = True\r
- getListTerms Term{subTerms=[h,t]} = h : getListTerms t\r
- getListTerms t@Term{subTerms=[]} = []\r
- getListTerms t@Suspension{} = [t]\r
- getListTerms t = pprPanic "getListTerms" (ppr t)\r
-\r
-isFullyEvaluatedTerm :: Term -> Bool\r
-isFullyEvaluatedTerm Term {subTerms=tt} = all isFullyEvaluatedTerm tt\r
-isFullyEvaluatedTerm Suspension {} = False\r
-isFullyEvaluatedTerm Prim {} = True\r
-\r
-\r
------------------------------------\r
--- Type Reconstruction\r
------------------------------------\r
-\r
--- The Type Reconstruction monad\r
-type TR a = TcM a\r
-\r
-runTR :: HscEnv -> TR Term -> IO Term\r
-runTR hsc_env c = do \r
- mb_term <- initTcPrintErrors hsc_env iNTERACTIVE (c >>= zonkTerm)\r
- case mb_term of \r
- Nothing -> panic "Can't unify"\r
- Just term -> return term\r
-\r
-trIO :: IO a -> TR a \r
-trIO = liftTcM . ioToTcRn\r
-\r
-addConstraint :: TcType -> TcType -> TR ()\r
-addConstraint t1 t2 = congruenceNewtypes t1 t2 >> unifyType t1 t2\r
-\r
--- A parallel fold over a Type value, replacing\r
--- in the right side reptypes for newtypes as found in the lhs\r
--- Sadly it doesn't cover all the possibilities. It does not always manage\r
--- to recover the highest level type. See test print016 for an example\r
-congruenceNewtypes :: TcType -> TcType -> TcM TcType\r
-congruenceNewtypes lhs rhs\r
--- | pprTrace "Congruence" (ppr lhs $$ ppr rhs) False = undefined\r
- -- We have a tctyvar at the other side\r
- | Just tv <- getTyVar_maybe rhs \r
--- , trace "congruence, entering tyvar" True\r
- = recoverM (return rhs) $ do \r
- Indirect ty_v <- readMetaTyVar tv\r
- newtyped_tytv <- congruenceNewtypes lhs ty_v\r
- writeMutVar (metaTvRef tv) (Indirect newtyped_tytv)\r
- return newtyped_tytv\r
--- We have a function type: go on inductively\r
- | Just (r1,r2) <- splitFunTy_maybe rhs\r
- , Just (l1,l2) <- splitFunTy_maybe lhs\r
- = liftM2 mkFunTy ( congruenceNewtypes l1 r1)\r
- (congruenceNewtypes l2 r2)\r
--- There is a newtype at the top level tycon and we can manage it\r
- | Just (tycon, args) <- splitNewTyConApp_maybe lhs\r
- , isNewTyCon tycon\r
- , (tvs, realtipe) <- newTyConRep tycon\r
- = case tcUnifyTys (const BindMe) [realtipe] [rhs] of\r
- Just subst -> \r
- let tvs' = substTys subst (map mkTyVarTy tvs) in\r
- liftM (mkTyConApp tycon) (zipWithM congruenceNewtypes args tvs')\r
- otherwise -> panic "congruenceNewtypes: Can't unify a newtype"\r
- \r
--- We have a TyconApp: go on inductively\r
- | Just (tycon, args) <- splitNewTyConApp_maybe lhs\r
- , Just (tycon_v, args_v) <- splitNewTyConApp_maybe rhs\r
- = liftM (mkTyConApp tycon_v) (zipWithM congruenceNewtypes args args_v)\r
-\r
- | otherwise = return rhs\r
-\r
-\r
-newVar :: Kind -> TR TcTyVar\r
-newVar = liftTcM . newFlexiTyVar\r
-\r
-liftTcM = id\r
-\r
-instScheme :: Type -> TR TcType\r
-instScheme ty = liftTcM$ liftM trd (tcInstType (liftM fst3 . tcInstTyVars) ty)\r
- where fst3 (x,y,z) = x\r
- trd (x,y,z) = z\r
-\r
-cvObtainTerm :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term\r
-cvObtainTerm hsc_env force mb_ty a = \r
- -- Obtain the term and tidy the type before returning it\r
- cvObtainTerm1 hsc_env force mb_ty a >>= return . tidyTypes \r
- where \r
- tidyTypes = foldTerm idTermFold {\r
- fTerm = \ty dc hval tt -> Term (tidy ty) dc hval tt,\r
- fSuspension = \ct mb_ty hval n -> \r
- Suspension ct (fmap tidy mb_ty) hval n\r
- }\r
- tidy ty = tidyType (emptyTidyOccEnv, tidyVarEnv ty) ty \r
- tidyVarEnv ty = \r
- mkVarEnv$ [ (v, setTyVarName v (tyVarName tv))\r
- | (tv,v) <- zip alphaTyVars vars]\r
- where vars = varSetElems$ tyVarsOfType ty\r
-\r
-cvObtainTerm1 :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term\r
-cvObtainTerm1 hsc_env force mb_ty hval\r
- | Nothing <- mb_ty = runTR hsc_env . go argTypeKind $ hval\r
- | Just ty <- mb_ty = runTR hsc_env $ do\r
- term <- go argTypeKind hval\r
- ty' <- instScheme ty\r
- addConstraint ty' (fromMaybe (error "by definition") \r
- (termType term)) \r
- return term\r
- where \r
- go k a = do \r
- ctype <- trIO$ getClosureType a\r
- case ctype of\r
--- Thunks we may want to force\r
- Thunk _ | force -> seq a $ go k a\r
--- We always follow indirections \r
- _ | isIndirection ctype \r
- -> do\r
- clos <- trIO$ getClosureData a\r
--- dflags <- getSessionDynFlags session\r
--- debugTraceMsg dflags 2 (text "Following an indirection")\r
- go k $! (ptrs clos ! 0)\r
- -- The interesting case\r
- Constr -> do\r
- m_dc <- trIO$ tcRnRecoverDataCon hsc_env a\r
- case m_dc of\r
- Nothing -> panic "Can't find the DataCon for a term"\r
- Just dc -> do \r
- clos <- trIO$ getClosureData a\r
- let extra_args = length(dataConRepArgTys dc) - length(dataConOrigArgTys dc)\r
- subTtypes = drop extra_args (dataConRepArgTys dc)\r
- (subTtypesP, subTtypesNP) = partition isPointed subTtypes\r
- \r
- subTermsP <- mapM (\i->extractSubterm i (ptrs clos)\r
- (subTtypesP!!(i-extra_args)))\r
- [extra_args..extra_args + length subTtypesP - 1]\r
- let unboxeds = extractUnboxed subTtypesNP (nonPtrs clos)\r
- subTermsNP = map (uncurry Prim) (zip subTtypesNP unboxeds) \r
- subTerms = reOrderTerms subTermsP subTermsNP subTtypes\r
- resType <- liftM mkTyVarTy (newVar k)\r
- baseType <- instScheme (dataConRepType dc)\r
- let myType = mkFunTys (map (fromMaybe undefined . termType) \r
- subTerms) \r
- resType\r
- addConstraint baseType myType\r
- return (Term resType dc a subTerms)\r
--- The otherwise case: can be a Thunk,AP,PAP,etc.\r
- otherwise -> do\r
- x <- liftM mkTyVarTy (newVar k)\r
- return (Suspension ctype (Just x) a Nothing)\r
-\r
--- Access the array of pointers and recurse down. Needs to be done with\r
--- care of no introducing a thunk! or go will fail to do its job \r
- extractSubterm (I# i#) ptrs ty = case ptrs of \r
- (Array _ _ ptrs#) -> case indexArray# ptrs# i# of \r
- (# e #) -> go (typeKind ty) e\r
-\r
--- This is used to put together pointed and nonpointed subterms in the \r
--- correct order.\r
- reOrderTerms _ _ [] = []\r
- reOrderTerms pointed unpointed (ty:tys) \r
- | isPointed ty = head pointed : reOrderTerms (tail pointed) unpointed tys\r
- | otherwise = head unpointed : reOrderTerms pointed (tail unpointed) tys\r
-\r
-zonkTerm :: Term -> TcM Term\r
-zonkTerm = foldTerm idTermFoldM {\r
- fTerm = \ty dc v tt -> sequence tt >>= \tt ->\r
- zonkTcType ty >>= \ty' ->\r
- return (Term ty' dc v tt)\r
- ,fSuspension = \ct ty v b -> fmapMMaybe zonkTcType ty >>= \ty ->\r
- return (Suspension ct ty v b)} \r
-\r
-{-\r
-Example of Type Reconstruction\r
---------------------------------\r
-Suppose we have an existential type such as\r
-\r
-data Opaque = forall a. Opaque a\r
-\r
-And we have a term built as:\r
-\r
-t = Opaque (map Just [[1,1],[2,2]])\r
-\r
-The type of t as far as the typechecker goes is t :: Opaque\r
-If we seq the head of t, we obtain:\r
-\r
-t - O (_1::a) \r
-\r
-seq _1 ()\r
-\r
-t - O ( (_3::b) : (_4::[b]) ) \r
-\r
-seq _3 ()\r
-\r
-t - O ( (Just (_5::c)) : (_4::[b]) ) \r
-\r
-At this point, we know that b = (Maybe c)\r
-\r
-seq _5 ()\r
-\r
-t - O ( (Just ((_6::d) : (_7::[d]) )) : (_4::[b]) )\r
-\r
-At this point, we know that c = [d]\r
-\r
-seq _6 ()\r
-\r
-t - O ( (Just (1 : (_7::[d]) )) : (_4::[b]) )\r
-\r
-At this point, we know that d = Integer\r
-\r
-The fully reconstructed expressions, with propagation, would be:\r
-\r
-t - O ( (Just (_5::c)) : (_4::[Maybe c]) ) \r
-t - O ( (Just ((_6::d) : (_7::[d]) )) : (_4::[Maybe [d]]) )\r
-t - O ( (Just (1 : (_7::[Integer]) )) : (_4::[Maybe [Integer]]) )\r
-\r
-\r
-For reference, the type of the thing inside the opaque is \r
-map Just [[1,1],[2,2]] :: [Maybe [Integer]]\r
-\r
-NOTE: (Num t) contexts have been manually replaced by Integer for clarity\r
--}\r
-\r
---------------------------------------------------------------------\r
--- The DataConEnv is used to store the addresses of datacons loaded\r
--- via the dynamic linker\r
---------------------------------------------------------------------\r
-\r
-type DataConEnv = AddressEnv StgInfoTable\r
-\r
--- Note that this AddressEnv and DataConEnv I wrote trying to follow \r
--- conventions in ghc, but probably they make not much sense.\r
-\r
-newtype AddressEnv a = AE {aenv:: FiniteMap (Ptr a) Name}\r
- deriving (Outputable)\r
-\r
-emptyAddressEnv = AE emptyFM\r
-\r
-extendAddressEnvList :: AddressEnv a -> [(Ptr a, Name)] -> AddressEnv a\r
-elemAddressEnv :: Ptr a -> AddressEnv a -> Bool\r
-delFromAddressEnv :: AddressEnv a -> Ptr a -> AddressEnv a\r
-nullAddressEnv :: AddressEnv a -> Bool\r
-lookupAddressEnv :: AddressEnv a -> Ptr a -> Maybe Name\r
-\r
-extendAddressEnvList (AE env) = AE . addListToFM env \r
-elemAddressEnv ptr (AE env) = ptr `elemFM` env\r
-delFromAddressEnv (AE env) = AE . delFromFM env\r
-nullAddressEnv = isEmptyFM . aenv\r
-lookupAddressEnv (AE env) = lookupFM env\r
-\r
-\r
-instance Outputable (Ptr a) where\r
- ppr = text . show
\ No newline at end of file
+-----------------------------------------------------------------------------
+--
+-- GHC Interactive support for inspecting arbitrary closures at runtime
+--
+-- Pepe Iborra (supported by Google SoC) 2006
+--
+-----------------------------------------------------------------------------
+
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
+module RtClosureInspect(
+
+ cvObtainTerm, -- :: HscEnv -> Int -> Bool -> Maybe Type -> HValue -> IO Term
+
+ Term(..),
+ isTerm,
+ isSuspension,
+ isPrim,
+ pprTerm,
+ cPprTerm,
+ cPprTermBase,
+ termType,
+ foldTerm,
+ TermFold(..),
+ idTermFold,
+ idTermFoldM,
+ isFullyEvaluated,
+ isPointed,
+ isFullyEvaluatedTerm,
+ mapTermType,
+ termTyVars,
+-- unsafeDeepSeq,
+ cvReconstructType,
+ computeRTTIsubst,
+ sigmaType,
+ Closure(..),
+ getClosureData,
+ ClosureType(..),
+ isConstr,
+ isIndirection
+ ) where
+
+#include "HsVersions.h"
+
+import ByteCodeItbls ( StgInfoTable )
+import qualified ByteCodeItbls as BCI( StgInfoTable(..) )
+import HscTypes ( HscEnv )
+import Linker
+
+import DataCon
+import Type
+import TcRnMonad ( TcM, initTc, ioToTcRn,
+ tryTcErrs)
+import TcType
+import TcMType
+import TcUnify
+import TcGadt
+import TcEnv
+import DriverPhases
+import TyCon
+import Name
+import VarEnv
+import Util
+import VarSet
+
+import TysPrim
+import PrelNames
+import TysWiredIn
+
+import Constants
+import Outputable
+import Maybes
+import Panic
+
+import GHC.Arr ( Array(..) )
+import GHC.Exts
+
+import Control.Monad
+import Data.Maybe
+import Data.Array.Base
+import Data.List ( partition )
+import qualified Data.Sequence as Seq
+import Data.Monoid
+import Data.Sequence hiding (null, length, index, take, drop, splitAt, reverse)
+import Foreign
+import System.IO.Unsafe
+
+---------------------------------------------
+-- * A representation of semi evaluated Terms
+---------------------------------------------
+{-
+ A few examples in this representation:
+
+ > Just 10 = Term Data.Maybe Data.Maybe.Just (Just 10) [Term Int I# (10) "10"]
+
+ > (('a',_,_),_,('b',_,_)) =
+ Term ((Char,b,c),d,(Char,e,f)) (,,) (('a',_,_),_,('b',_,_))
+ [ Term (Char, b, c) (,,) ('a',_,_) [Term Char C# "a", Suspension, Suspension]
+ , Suspension
+ , Term (Char, e, f) (,,) ('b',_,_) [Term Char C# "b", Suspension, Suspension]]
+-}
+
+data Term = Term { ty :: Type
+ , dc :: Either String DataCon
+ -- The heap datacon. If ty is a newtype,
+ -- this is NOT the newtype datacon.
+ -- Empty if the datacon aint exported by the .hi
+ -- (private constructors in -O0 libraries)
+ , val :: HValue
+ , subTerms :: [Term] }
+
+ | Prim { ty :: Type
+ , value :: [Word] }
+
+ | Suspension { ctype :: ClosureType
+ , mb_ty :: Maybe Type
+ , val :: HValue
+ , bound_to :: Maybe Name -- Useful for printing
+ }
+
+isTerm, isSuspension, isPrim :: Term -> Bool
+isTerm Term{} = True
+isTerm _ = False
+isSuspension Suspension{} = True
+isSuspension _ = False
+isPrim Prim{} = True
+isPrim _ = False
+
+termType :: Term -> Maybe Type
+termType t@(Suspension {}) = mb_ty t
+termType t = Just$ ty t
+
+isFullyEvaluatedTerm :: Term -> Bool
+isFullyEvaluatedTerm Term {subTerms=tt} = all isFullyEvaluatedTerm tt
+isFullyEvaluatedTerm Suspension {} = False
+isFullyEvaluatedTerm Prim {} = True
+
+instance Outputable (Term) where
+ ppr = head . cPprTerm cPprTermBase
+
+-------------------------------------------------------------------------
+-- Runtime Closure Datatype and functions for retrieving closure related stuff
+-------------------------------------------------------------------------
+data ClosureType = Constr
+ | Fun
+ | Thunk Int
+ | ThunkSelector
+ | Blackhole
+ | AP
+ | PAP
+ | Indirection Int
+ | Other Int
+ deriving (Show, Eq)
+
+data Closure = Closure { tipe :: ClosureType
+ , infoPtr :: Ptr ()
+ , infoTable :: StgInfoTable
+ , ptrs :: Array Int HValue
+ , nonPtrs :: [Word]
+ }
+
+instance Outputable ClosureType where
+ ppr = text . show
+
+#include "../includes/ClosureTypes.h"
+
+aP_CODE = AP
+pAP_CODE = PAP
+#undef AP
+#undef PAP
+
+getClosureData :: a -> IO Closure
+getClosureData a =
+ case unpackClosure# a of
+ (# iptr, ptrs, nptrs #) -> do
+ itbl <- peek (Ptr iptr)
+ let tipe = readCType (BCI.tipe itbl)
+ elems = fromIntegral (BCI.ptrs itbl)
+ ptrsList = Array 0 (elems - 1) elems ptrs
+ nptrs_data = [W# (indexWordArray# nptrs i)
+ | I# i <- [0.. fromIntegral (BCI.nptrs itbl)] ]
+ ASSERT(fromIntegral elems >= 0) return ()
+ ptrsList `seq`
+ return (Closure tipe (Ptr iptr) itbl ptrsList nptrs_data)
+
+readCType :: Integral a => a -> ClosureType
+readCType i
+ | i >= CONSTR && i <= CONSTR_NOCAF_STATIC = Constr
+ | i >= FUN && i <= FUN_STATIC = Fun
+ | i >= THUNK && i < THUNK_SELECTOR = Thunk (fromIntegral i)
+ | i == THUNK_SELECTOR = ThunkSelector
+ | i == BLACKHOLE = Blackhole
+ | i >= IND && i <= IND_STATIC = Indirection (fromIntegral i)
+ | fromIntegral i == aP_CODE = AP
+ | i == AP_STACK = AP
+ | fromIntegral i == pAP_CODE = PAP
+ | otherwise = Other (fromIntegral i)
+
+isConstr, isIndirection, isThunk :: ClosureType -> Bool
+isConstr Constr = True
+isConstr _ = False
+
+isIndirection (Indirection _) = True
+--isIndirection ThunkSelector = True
+isIndirection _ = False
+
+isThunk (Thunk _) = True
+isThunk ThunkSelector = True
+isThunk AP = True
+isThunk _ = False
+
+isFullyEvaluated :: a -> IO Bool
+isFullyEvaluated a = do
+ closure <- getClosureData a
+ case tipe closure of
+ Constr -> do are_subs_evaluated <- amapM isFullyEvaluated (ptrs closure)
+ return$ and are_subs_evaluated
+ otherwise -> return False
+ where amapM f = sequence . amap' f
+
+amap' f (Array i0 i _ arr#) = map g [0 .. i - i0]
+ where g (I# i#) = case indexArray# arr# i# of
+ (# e #) -> f e
+
+-- TODO: Fix it. Probably the otherwise case is failing, trace/debug it
+{-
+unsafeDeepSeq :: a -> b -> b
+unsafeDeepSeq = unsafeDeepSeq1 2
+ where unsafeDeepSeq1 0 a b = seq a $! b
+ unsafeDeepSeq1 i a b -- 1st case avoids infinite loops for non reducible thunks
+ | not (isConstr tipe) = seq a $! unsafeDeepSeq1 (i-1) a b
+ -- | unsafePerformIO (isFullyEvaluated a) = b
+ | otherwise = case unsafePerformIO (getClosureData a) of
+ closure -> foldl' (flip unsafeDeepSeq) b (ptrs closure)
+ where tipe = unsafePerformIO (getClosureType a)
+-}
+isPointed :: Type -> Bool
+isPointed t | Just (t, _) <- splitTyConApp_maybe t
+ = not$ isUnliftedTypeKind (tyConKind t)
+isPointed _ = True
+
+extractUnboxed :: [Type] -> Closure -> [[Word]]
+extractUnboxed tt clos = go tt (nonPtrs clos)
+ where sizeofType t
+ | Just (tycon,_) <- splitTyConApp_maybe t
+ = ASSERT (isPrimTyCon tycon) sizeofTyCon tycon
+ | otherwise = pprPanic "Expected a TcTyCon" (ppr t)
+ go [] _ = []
+ go (t:tt) xx
+ | (x, rest) <- splitAt ((sizeofType t + wORD_SIZE - 1) `div` wORD_SIZE) xx
+ = x : go tt rest
+
+sizeofTyCon = sizeofPrimRep . tyConPrimRep
+
+-----------------------------------
+-- * Traversals for Terms
+-----------------------------------
+
+data TermFold a = TermFold { fTerm :: Type -> Either String DataCon -> HValue -> [a] -> a
+ , fPrim :: Type -> [Word] -> a
+ , fSuspension :: ClosureType -> Maybe Type -> HValue
+ -> Maybe Name -> a
+ }
+
+foldTerm :: TermFold a -> Term -> a
+foldTerm tf (Term ty dc v tt) = fTerm tf ty dc v (map (foldTerm tf) tt)
+foldTerm tf (Prim ty v ) = fPrim tf ty v
+foldTerm tf (Suspension ct ty v b) = fSuspension tf ct ty v b
+
+idTermFold :: TermFold Term
+idTermFold = TermFold {
+ fTerm = Term,
+ fPrim = Prim,
+ fSuspension = Suspension
+ }
+idTermFoldM :: Monad m => TermFold (m Term)
+idTermFoldM = TermFold {
+ fTerm = \ty dc v tt -> sequence tt >>= return . Term ty dc v,
+ fPrim = (return.). Prim,
+ fSuspension = (((return.).).). Suspension
+ }
+
+mapTermType :: (Type -> Type) -> Term -> Term
+mapTermType f = foldTerm idTermFold {
+ fTerm = \ty dc hval tt -> Term (f ty) dc hval tt,
+ fSuspension = \ct mb_ty hval n ->
+ Suspension ct (fmap f mb_ty) hval n }
+
+termTyVars :: Term -> TyVarSet
+termTyVars = foldTerm TermFold {
+ fTerm = \ty _ _ tt ->
+ tyVarsOfType ty `plusVarEnv` concatVarEnv tt,
+ fSuspension = \_ mb_ty _ _ ->
+ maybe emptyVarEnv tyVarsOfType mb_ty,
+ fPrim = \ _ _ -> emptyVarEnv }
+ where concatVarEnv = foldr plusVarEnv emptyVarEnv
+----------------------------------
+-- Pretty printing of terms
+----------------------------------
+
+app_prec,cons_prec ::Int
+app_prec = 10
+cons_prec = 5 -- TODO Extract this info from GHC itself
+
+pprTerm y p t | Just doc <- pprTermM y p t = doc
+
+pprTermM :: Monad m => (Int -> Term -> m SDoc) -> Int -> Term -> m SDoc
+pprTermM y p t@Term{dc=Left dc_tag, subTerms=tt, ty=ty} = do
+ tt_docs <- mapM (y app_prec) tt
+ return$ cparen (not(null tt) && p >= app_prec) (text dc_tag <+> sep tt_docs)
+
+pprTermM y p t@Term{dc=Right dc, subTerms=tt, ty=ty}
+{- | dataConIsInfix dc, (t1:t2:tt') <- tt --TODO fixity
+ = parens (pprTerm1 True t1 <+> ppr dc <+> pprTerm1 True ppr t2)
+ <+> hsep (map (pprTerm1 True) tt)
+-} -- TODO Printing infix constructors properly
+ | null tt = return$ ppr dc
+ | Just (tc,_) <- splitNewTyConApp_maybe ty
+ , isNewTyCon tc
+ , Just new_dc <- maybeTyConSingleCon tc = do
+ real_value <- y 10 t{ty=repType ty}
+ return$ cparen (p >= app_prec) (ppr new_dc <+> real_value)
+ | otherwise = do
+ tt_docs <- mapM (y app_prec) tt
+ return$ cparen (p >= app_prec) (ppr dc <+> sep tt_docs)
+
+pprTermM y _ t = pprTermM1 y t
+pprTermM1 _ Prim{value=words, ty=ty} =
+ return$ text$ repPrim (tyConAppTyCon ty) words
+pprTermM1 y t@Term{} = panic "pprTermM1 - unreachable"
+pprTermM1 _ Suspension{bound_to=Nothing} = return$ char '_'
+pprTermM1 _ Suspension{mb_ty=Just ty, bound_to=Just n}
+ | Just _ <- splitFunTy_maybe ty = return$ ptext SLIT("<function>")
+ | otherwise = return$ parens$ ppr n <> text "::" <> ppr ty
+
+-- Takes a list of custom printers with a explicit recursion knot and a term,
+-- and returns the output of the first succesful printer, or the default printer
+cPprTerm :: forall m. Monad m =>
+ ((Int->Term->m SDoc)->[Int->Term->m (Maybe SDoc)]) -> Term -> m SDoc
+cPprTerm custom = go 0 where
+ go prec t@Term{} = do
+ let default_ prec t = Just `liftM` pprTermM go prec t
+ mb_customDocs = [pp prec t | pp <- custom go ++ [default_]]
+ Just doc <- firstJustM mb_customDocs
+ return$ cparen (prec>app_prec+1) doc
+ go _ t = pprTermM1 go t
+ firstJustM (mb:mbs) = mb >>= maybe (firstJustM mbs) (return . Just)
+ firstJustM [] = return Nothing
+
+-- Default set of custom printers. Note that the recursion knot is explicit
+cPprTermBase :: Monad m => (Int->Term-> m SDoc)->[Int->Term->m (Maybe SDoc)]
+cPprTermBase y =
+ [
+ ifTerm isTupleTy (\_ -> liftM (parens . hcat . punctuate comma)
+ . mapM (y (-1)) . subTerms)
+ , ifTerm (\t -> isTyCon listTyCon t && subTerms t `lengthIs` 2)
+ (\ p Term{subTerms=[h,t]} -> doList p h t)
+ , ifTerm (isTyCon intTyCon) (coerceShow$ \(a::Int)->a)
+ , ifTerm (isTyCon charTyCon) (coerceShow$ \(a::Char)->a)
+-- , ifTerm (isTyCon wordTyCon) (coerceShow$ \(a::Word)->a)
+ , ifTerm (isTyCon floatTyCon) (coerceShow$ \(a::Float)->a)
+ , ifTerm (isTyCon doubleTyCon) (coerceShow$ \(a::Double)->a)
+ , ifTerm isIntegerTy (coerceShow$ \(a::Integer)->a)
+ ]
+ where ifTerm pred f p t@Term{} | pred t = liftM Just (f p t)
+ ifTerm _ _ _ _ = return Nothing
+ isIntegerTy Term{ty=ty} = fromMaybe False $ do
+ (tc,_) <- splitTyConApp_maybe ty
+ return (tyConName tc == integerTyConName)
+ isTupleTy Term{ty=ty} = fromMaybe False $ do
+ (tc,_) <- splitTyConApp_maybe ty
+ return (tc `elem` (fst.unzip.elems) boxedTupleArr)
+ isTyCon a_tc Term{ty=ty} = fromMaybe False $ do
+ (tc,_) <- splitTyConApp_maybe ty
+ return (a_tc == tc)
+ coerceShow f _ = return . text . show . f . unsafeCoerce# . val
+ --TODO pprinting of list terms is not lazy
+ doList p h t = do
+ let elems = h : getListTerms t
+ isConsLast = termType(last elems) /= termType h
+ print_elems <- mapM (y cons_prec) elems
+ return$ if isConsLast
+ then cparen (p >= cons_prec) . hsep . punctuate (space<>colon)
+ $ print_elems
+ else brackets (hcat$ punctuate comma print_elems)
+
+ where Just a /= Just b = not (a `coreEqType` b)
+ _ /= _ = True
+ getListTerms Term{subTerms=[h,t]} = h : getListTerms t
+ getListTerms t@Term{subTerms=[]} = []
+ getListTerms t@Suspension{} = [t]
+ getListTerms t = pprPanic "getListTerms" (ppr t)
+
+
+repPrim :: TyCon -> [Word] -> String
+repPrim t = rep where
+ rep x
+ | t == charPrimTyCon = show (build x :: Char)
+ | t == intPrimTyCon = show (build x :: Int)
+ | t == wordPrimTyCon = show (build x :: Word)
+ | t == floatPrimTyCon = show (build x :: Float)
+ | t == doublePrimTyCon = show (build x :: Double)
+ | t == int32PrimTyCon = show (build x :: Int32)
+ | t == word32PrimTyCon = show (build x :: Word32)
+ | t == int64PrimTyCon = show (build x :: Int64)
+ | t == word64PrimTyCon = show (build x :: Word64)
+ | t == addrPrimTyCon = show (nullPtr `plusPtr` build x)
+ | t == stablePtrPrimTyCon = "<stablePtr>"
+ | t == stableNamePrimTyCon = "<stableName>"
+ | t == statePrimTyCon = "<statethread>"
+ | t == realWorldTyCon = "<realworld>"
+ | t == threadIdPrimTyCon = "<ThreadId>"
+ | t == weakPrimTyCon = "<Weak>"
+ | t == arrayPrimTyCon = "<array>"
+ | t == byteArrayPrimTyCon = "<bytearray>"
+ | t == mutableArrayPrimTyCon = "<mutableArray>"
+ | t == mutableByteArrayPrimTyCon = "<mutableByteArray>"
+ | t == mutVarPrimTyCon= "<mutVar>"
+ | t == mVarPrimTyCon = "<mVar>"
+ | t == tVarPrimTyCon = "<tVar>"
+ | otherwise = showSDoc (char '<' <> ppr t <> char '>')
+ where build ww = unsafePerformIO $ withArray ww (peek . castPtr)
+-- This ^^^ relies on the representation of Haskell heap values being
+-- the same as in a C array.
+
+-----------------------------------
+-- Type Reconstruction
+-----------------------------------
+{-
+Type Reconstruction is type inference done on heap closures.
+The algorithm walks the heap generating a set of equations, which
+are solved with syntactic unification.
+A type reconstruction equation looks like:
+
+ <datacon reptype> = <actual heap contents>
+
+The full equation set is generated by traversing all the subterms, starting
+from a given term.
+
+The only difficult part is that newtypes are only found in the lhs of equations.
+Right hand sides are missing them. We can either (a) drop them from the lhs, or
+(b) reconstruct them in the rhs when possible.
+
+The function congruenceNewtypes takes a shot at (b)
+-}
+
+-- The Type Reconstruction monad
+type TR a = TcM a
+
+runTR :: HscEnv -> TR a -> IO a
+runTR hsc_env c = do
+ mb_term <- runTR_maybe hsc_env c
+ case mb_term of
+ Nothing -> panic "Can't unify"
+ Just x -> return x
+
+runTR_maybe :: HscEnv -> TR a -> IO (Maybe a)
+runTR_maybe hsc_env = fmap snd . initTc hsc_env HsSrcFile False iNTERACTIVE
+
+trIO :: IO a -> TR a
+trIO = liftTcM . ioToTcRn
+
+liftTcM :: TcM a -> TR a
+liftTcM = id
+
+newVar :: Kind -> TR TcType
+newVar = liftTcM . fmap mkTyVarTy . newFlexiTyVar
+
+-- | Returns the instantiated type scheme ty', and the substitution sigma
+-- such that sigma(ty') = ty
+instScheme :: Type -> TR (TcType, TvSubst)
+instScheme ty | (tvs, rho) <- tcSplitForAllTys ty = liftTcM$ do
+ (tvs',theta,ty') <- tcInstType (mapM tcInstTyVar) ty
+ return (ty', zipTopTvSubst tvs' (mkTyVarTys tvs))
+
+-- Adds a constraint of the form t1 == t2
+-- t1 is expected to come from walking the heap
+-- t2 is expected to come from a datacon signature
+-- Before unification, congruenceNewtypes needs to
+-- do its magic.
+addConstraint :: TcType -> TcType -> TR ()
+addConstraint t1 t2 = congruenceNewtypes t1 t2 >>= uncurry unifyType
+ >> return () -- TOMDO: what about the coercion?
+ -- we should consider family instances
+
+-- Type & Term reconstruction
+cvObtainTerm :: HscEnv -> Int -> Bool -> Maybe Type -> HValue -> IO Term
+cvObtainTerm hsc_env bound force mb_ty hval = runTR hsc_env $ do
+ tv <- newVar argTypeKind
+ case mb_ty of
+ Nothing -> go bound tv tv hval >>= zonkTerm
+ Just ty | isMonomorphic ty -> go bound ty ty hval >>= zonkTerm
+ Just ty -> do
+ (ty',rev_subst) <- instScheme (sigmaType ty)
+ addConstraint tv ty'
+ term <- go bound tv tv hval >>= zonkTerm
+ --restore original Tyvars
+ return$ mapTermType (substTy rev_subst) term
+ where
+ go bound _ _ _ | seq bound False = undefined
+ go 0 tv ty a = do
+ clos <- trIO $ getClosureData a
+ return (Suspension (tipe clos) (Just tv) a Nothing)
+ go bound tv ty a = do
+ let monomorphic = not(isTyVarTy tv)
+ -- This ^^^ is a convention. The ancestor tests for
+ -- monomorphism and passes a type instead of a tv
+ clos <- trIO $ getClosureData a
+ case tipe clos of
+-- Thunks we may want to force
+-- NB. this won't attempt to force a BLACKHOLE. Even with :force, we never
+-- force blackholes, because it would almost certainly result in deadlock,
+-- and showing the '_' is more useful.
+ t | isThunk t && force -> seq a $ go (pred bound) tv ty a
+-- We always follow indirections
+ Indirection _ -> go (pred bound) tv ty $! (ptrs clos ! 0)
+ -- The interesting case
+ Constr -> do
+ Right dcname <- dataConInfoPtrToName (infoPtr clos)
+ (_,mb_dc) <- tryTcErrs (tcLookupDataCon dcname)
+ case mb_dc of
+ Nothing -> do -- This can happen for private constructors compiled -O0
+ -- where the .hi descriptor does not export them
+ -- In such case, we return a best approximation:
+ -- ignore the unpointed args, and recover the pointeds
+ -- This preserves laziness, and should be safe.
+ let tag = showSDoc (ppr dcname)
+ vars <- replicateM (length$ elems$ ptrs clos)
+ (newVar (liftedTypeKind))
+ subTerms <- sequence [appArr (go (pred bound) tv tv) (ptrs clos) i
+ | (i, tv) <- zip [0..] vars]
+ return (Term tv (Left ('<' : tag ++ ">")) a subTerms)
+ Just dc -> do
+ let extra_args = length(dataConRepArgTys dc) -
+ length(dataConOrigArgTys dc)
+ subTtypes = matchSubTypes dc ty
+ (subTtypesP, subTtypesNP) = partition isPointed subTtypes
+ subTermTvs <- sequence
+ [ if isMonomorphic t then return t
+ else (newVar k)
+ | (t,k) <- zip subTtypesP (map typeKind subTtypesP)]
+ -- It is vital for newtype reconstruction that the unification step
+ -- is done right here, _before_ the subterms are RTTI reconstructed
+ when (not monomorphic) $ do
+ let myType = mkFunTys (reOrderTerms subTermTvs
+ subTtypesNP
+ subTtypes)
+ tv
+ (signatureType,_) <- instScheme(dataConRepType dc)
+ addConstraint myType signatureType
+ subTermsP <- sequence $ drop extra_args
+ -- ^^^ all extra arguments are pointed
+ [ appArr (go (pred bound) tv t) (ptrs clos) i
+ | (i,tv,t) <- zip3 [0..] subTermTvs subTtypesP]
+ let unboxeds = extractUnboxed subTtypesNP clos
+ subTermsNP = map (uncurry Prim) (zip subTtypesNP unboxeds)
+ subTerms = reOrderTerms subTermsP subTermsNP
+ (drop extra_args subTtypes)
+ return (Term tv (Right dc) a subTerms)
+-- The otherwise case: can be a Thunk,AP,PAP,etc.
+ tipe_clos ->
+ return (Suspension tipe_clos (Just tv) a Nothing)
+
+-- matchSubTypes dc ty | pprTrace "matchSubtypes" (ppr dc <+> ppr ty) False = undefined
+ matchSubTypes dc ty
+ | Just (_,ty_args) <- splitTyConApp_maybe (repType ty)
+-- assumption: ^^^ looks through newtypes
+ , isVanillaDataCon dc --TODO non-vanilla case
+ = dataConInstArgTys dc ty_args
+ | otherwise = dataConRepArgTys dc
+
+-- This is used to put together pointed and nonpointed subterms in the
+-- correct order.
+ reOrderTerms _ _ [] = []
+ reOrderTerms pointed unpointed (ty:tys)
+ | isPointed ty = ASSERT2(not(null pointed)
+ , ptext SLIT("reOrderTerms") $$
+ (ppr pointed $$ ppr unpointed))
+ head pointed : reOrderTerms (tail pointed) unpointed tys
+ | otherwise = ASSERT2(not(null unpointed)
+ , ptext SLIT("reOrderTerms") $$
+ (ppr pointed $$ ppr unpointed))
+ head unpointed : reOrderTerms pointed (tail unpointed) tys
+
+
+
+-- Fast, breadth-first Type reconstruction
+max_depth = 10 :: Int
+cvReconstructType :: HscEnv -> Bool -> Maybe Type -> HValue -> IO (Maybe Type)
+cvReconstructType hsc_env force mb_ty hval = runTR_maybe hsc_env $ do
+ tv <- newVar argTypeKind
+ case mb_ty of
+ Nothing -> do search (isMonomorphic `fmap` zonkTcType tv)
+ (uncurry go)
+ (Seq.singleton (tv, hval))
+ max_depth
+ zonkTcType tv -- TODO untested!
+ Just ty | isMonomorphic ty -> return ty
+ Just ty -> do
+ (ty',rev_subst) <- instScheme (sigmaType ty)
+ addConstraint tv ty'
+ search (isMonomorphic `fmap` zonkTcType tv)
+ (\(ty,a) -> go ty a)
+ (Seq.singleton (tv, hval))
+ max_depth
+ substTy rev_subst `fmap` zonkTcType tv
+ where
+-- search :: m Bool -> ([a] -> [a] -> [a]) -> [a] -> m ()
+ search stop expand l depth | Seq.null l = return ()
+ search stop expand x 0 = fail$ "Failed to reconstruct a type after " ++
+ show max_depth ++ " steps"
+ search stop expand l d | x :< xx <- viewl l = unlessM stop $ do
+ new <- expand x
+ search stop expand (xx `mappend` Seq.fromList new) $! (pred d)
+
+ -- returns unification tasks,since we are going to want a breadth-first search
+ go :: Type -> HValue -> TR [(Type, HValue)]
+ go tv a = do
+ clos <- trIO $ getClosureData a
+ case tipe clos of
+ Indirection _ -> go tv $! (ptrs clos ! 0)
+ Constr -> do
+ Right dcname <- dataConInfoPtrToName (infoPtr clos)
+ (_,mb_dc) <- tryTcErrs (tcLookupDataCon dcname)
+ case mb_dc of
+ Nothing-> do
+ -- TODO: Check this case
+ vars <- replicateM (length$ elems$ ptrs clos)
+ (newVar (liftedTypeKind))
+ subTerms <- sequence [ appArr (go tv) (ptrs clos) i
+ | (i, tv) <- zip [0..] vars]
+ forM [0..length (elems $ ptrs clos)] $ \i -> do
+ tv <- newVar liftedTypeKind
+ return$ appArr (\e->(tv,e)) (ptrs clos) i
+
+ Just dc -> do
+ let extra_args = length(dataConRepArgTys dc) -
+ length(dataConOrigArgTys dc)
+ subTtypes <- mapMif (not . isMonomorphic)
+ (\t -> newVar (typeKind t))
+ (dataConRepArgTys dc)
+
+ -- It is vital for newtype reconstruction that the unification step
+ -- is done right here, _before_ the subterms are RTTI reconstructed
+ let myType = mkFunTys subTtypes tv
+ (signatureType,_) <- instScheme(dataConRepType dc)
+ addConstraint myType signatureType
+ return $ [ appArr (\e->(t,e)) (ptrs clos) i
+ | (i,t) <- drop extra_args $
+ zip [0..] (filter isPointed subTtypes)]
+ otherwise -> return []
+
+ -- This helper computes the difference between a base type t and the
+ -- improved rtti_t computed by RTTI
+ -- The main difference between RTTI types and their normal counterparts
+ -- is that the former are _not_ polymorphic, thus polymorphism must
+ -- be stripped. Syntactically, forall's must be stripped
+computeRTTIsubst ty rtti_ty =
+ -- In addition, we strip newtypes too, since the reconstructed type might
+ -- not have recovered them all
+ tcUnifyTys (const BindMe)
+ [repType' $ dropForAlls$ ty]
+ [repType' $ rtti_ty]
+-- TODO stripping newtypes shouldn't be necessary, test
+
+
+-- Dealing with newtypes
+{-
+ A parallel fold over two Type values,
+ compensating for missing newtypes on both sides.
+ This is necessary because newtypes are not present
+ in runtime, but since sometimes there is evidence
+ available we do our best to reconstruct them.
+ Evidence can come from DataCon signatures or
+ from compile-time type inference.
+ I am using the words congruence and rewriting
+ because what we are doing here is an approximation
+ of unification modulo a set of equations, which would
+ come from newtype definitions. These should be the
+ equality coercions seen in System Fc. Rewriting
+ is performed, taking those equations as rules,
+ before launching unification.
+
+ It doesn't make sense to rewrite everywhere,
+ or we would end up with all newtypes. So we rewrite
+ only in presence of evidence.
+ The lhs comes from the heap structure of ptrs,nptrs.
+ The rhs comes from a DataCon type signature.
+ Rewriting in the rhs is restricted to the result type.
+
+ Note that it is very tricky to make this 'rewriting'
+ work with the unification implemented by TcM, where
+ substitutions are 'inlined'. The order in which
+ constraints are unified is vital for this (or I am
+ using TcM wrongly).
+-}
+congruenceNewtypes :: TcType -> TcType -> TcM (TcType,TcType)
+congruenceNewtypes lhs rhs
+ -- TyVar lhs inductive case
+ | Just tv <- getTyVar_maybe lhs
+ = recoverTc (return (lhs,rhs)) $ do
+ Indirect ty_v <- readMetaTyVar tv
+ (lhs1, rhs1) <- congruenceNewtypes ty_v rhs
+ return (lhs, rhs1)
+-- FunTy inductive case
+ | Just (l1,l2) <- splitFunTy_maybe lhs
+ , Just (r1,r2) <- splitFunTy_maybe rhs
+ = do (l2',r2') <- congruenceNewtypes l2 r2
+ (l1',r1') <- congruenceNewtypes l1 r1
+ return (mkFunTy l1' l2', mkFunTy r1' r2')
+-- TyconApp Inductive case; this is the interesting bit.
+ | Just (tycon_l, args_l) <- splitNewTyConApp_maybe lhs
+ , Just (tycon_r, args_r) <- splitNewTyConApp_maybe rhs
+ , tycon_l /= tycon_r
+ = return (lhs, upgrade tycon_l rhs)
+
+ | otherwise = return (lhs,rhs)
+
+ where upgrade :: TyCon -> Type -> Type
+ upgrade new_tycon ty
+ | not (isNewTyCon new_tycon) = ty
+ | ty' <- mkTyConApp new_tycon (map mkTyVarTy $ tyConTyVars new_tycon)
+ , Just subst <- tcUnifyTys (const BindMe) [ty] [repType ty']
+ = substTy subst ty'
+ -- assumes that reptype doesn't touch tyconApp args ^^^
+
+
+--------------------------------------------------------------------------------
+-- Semantically different to recoverM in TcRnMonad
+-- recoverM retains the errors in the first action,
+-- whereas recoverTc here does not
+recoverTc recover thing = do
+ (_,mb_res) <- tryTcErrs thing
+ case mb_res of
+ Nothing -> recover
+ Just res -> return res
+
+isMonomorphic ty | (tvs, ty') <- splitForAllTys ty
+ = null tvs && (isEmptyVarSet . tyVarsOfType) ty'
+
+mapMif :: Monad m => (a -> Bool) -> (a -> m a) -> [a] -> m [a]
+mapMif pred f xx = sequence $ mapMif_ pred f xx
+mapMif_ pred f [] = []
+mapMif_ pred f (x:xx) = (if pred x then f x else return x) : mapMif_ pred f xx
+
+unlessM condM acc = condM >>= \c -> unless c acc
+
+-- Strict application of f at index i
+appArr f a@(Array _ _ _ ptrs#) i@(I# i#)
+ = ASSERT (i < length(elems a))
+ case indexArray# ptrs# i# of
+ (# e #) -> f e
+
+zonkTerm :: Term -> TcM Term
+zonkTerm = foldTerm idTermFoldM {
+ fTerm = \ty dc v tt -> sequence tt >>= \tt ->
+ zonkTcType ty >>= \ty' ->
+ return (Term ty' dc v tt)
+ ,fSuspension = \ct ty v b -> fmapMMaybe zonkTcType ty >>= \ty ->
+ return (Suspension ct ty v b)}
+
+
+-- Is this defined elsewhere?
+-- Generalize the type: find all free tyvars and wrap in the appropiate ForAll.
+sigmaType ty = mkForAllTys (varSetElems$ tyVarsOfType (dropForAlls ty)) ty
+
+
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