X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fghci%2FRtClosureInspect.hs;h=e2a4f8e6088882806ac9d7b456530e181c552a69;hp=9161ae43f463afcd7412cb4e7e5336dbf02745cf;hb=7fc749a43b4b6b85d234fa95d4928648259584f4;hpb=2c92736ea5a4aedf263a77d58c6e9b032a05b7ef diff --git a/compiler/ghci/RtClosureInspect.hs b/compiler/ghci/RtClosureInspect.hs index 9161ae4..e2a4f8e 100644 --- a/compiler/ghci/RtClosureInspect.hs +++ b/compiler/ghci/RtClosureInspect.hs @@ -1,635 +1,772 @@ ------------------------------------------------------------------------------ --- --- GHC Interactive support for inspecting arbitrary closures at runtime --- --- Pepe Iborra (supported by Google SoC) 2006 --- ------------------------------------------------------------------------------ - -module RtClosureInspect( - - cvObtainTerm, -- :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term - - AddressEnv(..), - DataConEnv, - extendAddressEnvList, - extendAddressEnvList', - elemAddressEnv, - delFromAddressEnv, - emptyAddressEnv, - lookupAddressEnv, - - ClosureType(..), - getClosureData, - Closure ( tipe, infoTable, ptrs, nonPtrs ), - getClosureType, - isConstr, - isIndirection, - getInfoTablePtr, - - Term(..), - printTerm, - customPrintTerm, - customPrintTermBase, - termType, - foldTerm, - TermFold(..), - idTermFold, - idTermFoldM, - isFullyEvaluated, - isPointed, - isFullyEvaluatedTerm, --- unsafeDeepSeq, - ) where - -#include "HsVersions.h" - -import ByteCodeItbls ( StgInfoTable ) -import qualified ByteCodeItbls as BCI( StgInfoTable(..) ) -import ByteCodeLink ( HValue ) -import HscTypes ( HscEnv ) - -import DataCon -import Type -import TcRnMonad -import TcType -import TcMType -import TcUnify -import TcGadt -import DriverPhases -import TyCon -import Var -import Name -import Unique -import UniqSupply -import Var ( setVarUnique, mkTyVar, tyVarKind, setTyVarKind ) -import VarEnv ( mkVarEnv ) -import OccName ( emptyTidyOccEnv ) -import VarSet ( VarSet, mkVarSet, varSetElems, unionVarSets ) -import Unique ( getUnique, incrUnique ) -import {-#SOURCE#-} TcRnDriver ( tcRnRecoverDataCon ) - -import TysPrim -import PrelNames -import TysWiredIn - -import Constants ( wORD_SIZE ) -import FastString ( mkFastString ) -import Outputable -import Panic - -import GHC.Arr ( Array(..) ) -import GHC.Ptr ( Ptr(..), castPtr ) -import GHC.Exts -import GHC.Int ( Int32(..), Int64(..) ) -import GHC.Word ( Word32(..), Word64(..) ) - -import Control.Monad ( liftM, liftM2, msum ) -import Data.Maybe -import Data.List -import Data.Traversable ( mapM ) -import Data.Array.Base -import Foreign.Storable -import Foreign ( unsafePerformIO ) - -import Prelude hiding ( mapM ) - ---------------------------------------------- --- * 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", Thunk, Thunk] - , Thunk - , Term (Char, e, f) (,,) ('b',_,_) [Term Char C# "b", Thunk, Thunk]] --} - -data Term = Term { ty :: Type - , dc :: DataCon - , val :: HValue - , subTerms :: [Term] } - - | Prim { ty :: Type - , value :: String } - - | Suspension { ctype :: ClosureType - , mb_ty :: Maybe Type - , val :: HValue - , bound_to :: Maybe Name -- Useful for printing - } - -isTerm Term{} = True -isTerm _ = False -isSuspension Suspension{} = True -isSuspension _ = False -isPrim Prim{} = True -isPrim _ = False - -termType t@(Suspension {}) = mb_ty t -termType t = Just$ ty t - -instance Outputable (Term) where - ppr = head . customPrintTerm customPrintTermBase - -------------------------------------------------------------------------- --- 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 - , infoTable :: StgInfoTable - , ptrs :: Array Int HValue - -- What would be the type here? HValue is ok? Should I build a Ptr? - , nonPtrs :: ByteArray# - } - -instance Outputable ClosureType where - ppr = text . show - -getInfoTablePtr :: a -> Ptr StgInfoTable -getInfoTablePtr x = - case infoPtr# x of - itbl_ptr -> castPtr ( Ptr itbl_ptr ) - -getClosureType :: a -> IO ClosureType -getClosureType = liftM (readCType . BCI.tipe ) . peek . getInfoTablePtr - -#include "../includes/ClosureTypes.h" - -aP_CODE = AP -pAP_CODE = PAP -#undef AP -#undef PAP - -getClosureData :: a -> IO Closure -getClosureData a = do - itbl <- peek (getInfoTablePtr a) - let tipe = readCType (BCI.tipe itbl) - case closurePayload# a of - (# ptrs, nptrs #) -> - let elems = BCI.ptrs itbl - ptrsList = Array 0 (fromIntegral$ elems) ptrs - in ptrsList `seq` return (Closure tipe itbl ptrsList nptrs) - -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 - | fromIntegral i == pAP_CODE = PAP - | otherwise = Other (fromIntegral i) - -isConstr, isIndirection :: ClosureType -> Bool -isConstr Constr = True -isConstr _ = False - -isIndirection (Indirection _) = True ---isIndirection ThunkSelector = True -isIndirection _ = 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 (\(I# i#) -> case indexArray# arr# i# of - (# e #) -> f e) - [0 .. i - i0] - --- 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 - -#define MKDECODER(offset,cons,builder) (offset, show$ cons (builder addr 0#)) - -extractUnboxed :: [Type] -> ByteArray# -> [String] -extractUnboxed tt ba = helper tt (byteArrayContents# ba) - where helper :: [Type] -> Addr# -> [String] - helper (t:tt) addr - | Just ( tycon,_) <- splitTyConApp_maybe t - = let (offset, txt) = decode tycon addr - (I# word_offset) = offset*wORD_SIZE - in txt : helper tt (plusAddr# addr word_offset) - | otherwise - = -- ["extractUnboxed.helper: Urk. I got a " ++ showSDoc (ppr t)] - panic$ "extractUnboxed.helper: Urk. I got a " ++ showSDoc (ppr t) - helper [] addr = [] - decode :: TyCon -> Addr# -> (Int, String) - decode t addr - | t == charPrimTyCon = MKDECODER(1,C#,indexCharOffAddr#) - | t == intPrimTyCon = MKDECODER(1,I#,indexIntOffAddr#) - | t == wordPrimTyCon = MKDECODER(1,W#,indexWordOffAddr#) - | t == floatPrimTyCon = MKDECODER(1,F#,indexFloatOffAddr#) - | t == doublePrimTyCon = MKDECODER(2,D#,indexDoubleOffAddr#) - | t == int32PrimTyCon = MKDECODER(1,I32#,indexInt32OffAddr#) - | t == word32PrimTyCon = MKDECODER(1,W32#,indexWord32OffAddr#) - | t == int64PrimTyCon = MKDECODER(2,I64#,indexInt64OffAddr#) - | t == word64PrimTyCon = MKDECODER(2,W64#,indexWord64OffAddr#) - | t == addrPrimTyCon = MKDECODER(1,I#,(\x off-> addr2Int# (indexAddrOffAddr# x off))) --OPT Improve the presentation of addresses - | t == stablePtrPrimTyCon = (1, "") - | t == stableNamePrimTyCon = (1, "") - | t == statePrimTyCon = (1, "") - | t == realWorldTyCon = (1, "") - | t == threadIdPrimTyCon = (1, "") - | t == weakPrimTyCon = (1, "") - | t == arrayPrimTyCon = (1,"") - | t == byteArrayPrimTyCon = (1,"") - | t == mutableArrayPrimTyCon = (1, "") - | t == mutableByteArrayPrimTyCon = (1, "") - | t == mutVarPrimTyCon= (1, "") - | t == mVarPrimTyCon = (1, "") - | t == tVarPrimTyCon = (1, "") - | otherwise = (1, showSDoc (char '<' <> ppr t <> char '>')) - -- We cannot know the right offset in the otherwise case, so 1 is just a wild dangerous guess! - -- TODO: Improve the offset handling in decode (make it machine dependant) - ------------------------------------ --- Boilerplate Fold code for Term ------------------------------------ - -data TermFold a = TermFold { fTerm :: Type -> DataCon -> HValue -> [a] -> a - , fPrim :: Type -> String -> 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 - } - ----------------------------------- --- Pretty printing of terms ----------------------------------- - -parensCond True = parens -parensCond False = id -app_prec::Int -app_prec = 10 - -printTerm :: Term -> SDoc -printTerm Prim{value=value} = text value -printTerm t@Term{} = printTerm1 0 t -printTerm Suspension{bound_to=Nothing} = char '_' -- <> ppr ct <> char '_' -printTerm Suspension{mb_ty=Just ty, bound_to=Just n} = - parens$ ppr n <> text "::" <> ppr ty - -printTerm1 p Term{dc=dc, subTerms=tt} -{- | dataConIsInfix dc, (t1:t2:tt') <- tt - = parens (printTerm1 True t1 <+> ppr dc <+> printTerm1 True ppr t2) - <+> hsep (map (printTerm1 True) tt) --} - | null tt = ppr dc - | otherwise = parensCond (p > app_prec) - (ppr dc <+> sep (map (printTerm1 (app_prec+1)) tt)) - - where fixity = undefined - -printTerm1 _ t = printTerm t - -customPrintTerm :: Monad m => ((Int->Term->m SDoc)->[Term->m (Maybe SDoc)]) -> Term -> m SDoc -customPrintTerm custom = let --- go :: Monad m => Int -> Term -> m SDoc - go prec t@Term{subTerms=tt, dc=dc} = do - mb_customDocs <- sequence$ sequence (custom go) t -- Inner sequence is List monad - case msum mb_customDocs of -- msum is in Maybe monad - Just doc -> return$ parensCond (prec>app_prec+1) doc --- | dataConIsInfix dc, (t1:t2:tt') <- tt = - Nothing -> do pprSubterms <- mapM (go (app_prec+1)) tt - return$ parensCond (prec>app_prec+1) - (ppr dc <+> sep pprSubterms) - go _ t = return$ printTerm t - in go 0 - where fixity = undefined - -customPrintTermBase :: Monad m => (Int->Term-> m SDoc)->[Term->m (Maybe SDoc)] -customPrintTermBase showP = - [ - test isTupleDC (liftM (parens . cat . punctuate comma) . mapM (showP 0) . subTerms) - , test (isDC consDataCon) (\Term{subTerms=[h,t]} -> doList h t) - , test (isDC intDataCon) (coerceShow$ \(a::Int)->a) - , test (isDC charDataCon) (coerceShow$ \(a::Char)->a) --- , test (isDC wordDataCon) (coerceShow$ \(a::Word)->a) - , test (isDC floatDataCon) (coerceShow$ \(a::Float)->a) - , test (isDC doubleDataCon) (coerceShow$ \(a::Double)->a) - , test isIntegerDC (coerceShow$ \(a::Integer)->a) - ] - where test pred f t = if pred t then liftM Just (f t) else return Nothing - isIntegerDC Term{dc=dc} = - dataConName dc `elem` [ smallIntegerDataConName - , largeIntegerDataConName] - isTupleDC Term{dc=dc} = dc `elem` snd (unzip (elems boxedTupleArr)) - isDC a_dc Term{dc=dc} = a_dc == dc - coerceShow f Term{val=val} = return . text . show . f . unsafeCoerce# $ val - --TODO pprinting of list terms is not lazy - doList h t = do - let elems = h : getListTerms t - isConsLast = isSuspension (last elems) && - (mb_ty$ last elems) /= (termType h) - init <- mapM (showP 0) (init elems) - last0 <- showP 0 (last elems) - let last = case length elems of - 1 -> last0 - _ | isConsLast -> text " | " <> last0 - _ -> comma <> last0 - return$ brackets (cat (punctuate comma init ++ [last])) - - 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) - -isFullyEvaluatedTerm :: Term -> Bool -isFullyEvaluatedTerm Term {subTerms=tt} = all isFullyEvaluatedTerm tt -isFullyEvaluatedTerm Suspension {} = False -isFullyEvaluatedTerm Prim {} = True - - ------------------------------------ --- Type Reconstruction ------------------------------------ - --- The Type Reconstruction monad -type TR a = TcM a - -runTR :: HscEnv -> TR Term -> IO Term -runTR hsc_env c = do - mb_term <- initTcPrintErrors hsc_env iNTERACTIVE (c >>= zonkTerm) - case mb_term of - Nothing -> panic "Can't unify" - Just term -> return term - -trIO :: IO a -> TR a -trIO = liftTcM . ioToTcRn - -addConstraint :: TcType -> TcType -> TR () -addConstraint t1 t2 = congruenceNewtypes t1 t2 >> unifyType t1 t2 - --- A parallel fold over a Type value, replacing --- in the right side reptypes for newtypes as found in the lhs --- Sadly it doesn't cover all the possibilities. It does not always manage --- to recover the highest level type. See test print016 for an example -congruenceNewtypes :: TcType -> TcType -> TcM TcType -congruenceNewtypes lhs rhs --- | pprTrace "Congruence" (ppr lhs $$ ppr rhs) False = undefined - -- We have a tctyvar at the other side - | Just tv <- getTyVar_maybe rhs --- , trace "congruence, entering tyvar" True - = recoverM (return rhs) $ do - Indirect ty_v <- readMetaTyVar tv - newtyped_tytv <- congruenceNewtypes lhs ty_v - writeMutVar (metaTvRef tv) (Indirect newtyped_tytv) - return newtyped_tytv --- We have a function type: go on inductively - | Just (r1,r2) <- splitFunTy_maybe rhs - , Just (l1,l2) <- splitFunTy_maybe lhs - = liftM2 mkFunTy ( congruenceNewtypes l1 r1) - (congruenceNewtypes l2 r2) --- There is a newtype at the top level tycon and we can manage it - | Just (tycon, args) <- splitNewTyConApp_maybe lhs - , isNewTyCon tycon - , (tvs, realtipe) <- newTyConRep tycon - = case tcUnifyTys (const BindMe) [realtipe] [rhs] of - Just subst -> - let tvs' = substTys subst (map mkTyVarTy tvs) in - liftM (mkTyConApp tycon) (zipWithM congruenceNewtypes args tvs') - otherwise -> panic "congruenceNewtypes: Can't unify a newtype" - --- We have a TyconApp: go on inductively - | Just (tycon, args) <- splitNewTyConApp_maybe lhs - , Just (tycon_v, args_v) <- splitNewTyConApp_maybe rhs - = liftM (mkTyConApp tycon_v) (zipWithM congruenceNewtypes args args_v) - - | otherwise = return rhs - - -newVar :: Kind -> TR TcTyVar -newVar = liftTcM . newFlexiTyVar - -liftTcM = id - -instScheme :: Type -> TR TcType -instScheme ty = liftTcM$ liftM trd (tcInstType (liftM fst3 . tcInstTyVars) ty) - where fst3 (x,y,z) = x - trd (x,y,z) = z - -cvObtainTerm :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term -cvObtainTerm hsc_env force mb_ty a = - -- Obtain the term and tidy the type before returning it - cvObtainTerm1 hsc_env force mb_ty a >>= return . tidyTypes - where - tidyTypes = foldTerm idTermFold { - fTerm = \ty dc hval tt -> Term (tidy ty) dc hval tt, - fSuspension = \ct mb_ty hval n -> - Suspension ct (fmap tidy mb_ty) hval n - } - tidy ty = tidyType (emptyTidyOccEnv, tidyVarEnv ty) ty - tidyVarEnv ty = - mkVarEnv$ [ (v, setTyVarName v (tyVarName tv)) - | (tv,v) <- zip alphaTyVars vars] - where vars = varSetElems$ tyVarsOfType ty - -cvObtainTerm1 :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term -cvObtainTerm1 hsc_env force mb_ty hval - | Nothing <- mb_ty = runTR hsc_env . go argTypeKind $ hval - | Just ty <- mb_ty = runTR hsc_env $ do - term <- go argTypeKind hval - ty' <- instScheme ty - addConstraint ty' (fromMaybe (error "by definition") - (termType term)) - return term - where - go k a = do - ctype <- trIO$ getClosureType a - case ctype of --- Thunks we may want to force - Thunk _ | force -> seq a $ go k a --- We always follow indirections - _ | isIndirection ctype - -> do - clos <- trIO$ getClosureData a --- dflags <- getSessionDynFlags session --- debugTraceMsg dflags 2 (text "Following an indirection") - go k $! (ptrs clos ! 0) - -- The interesting case - Constr -> do - m_dc <- trIO$ tcRnRecoverDataCon hsc_env a - case m_dc of - Nothing -> panic "Can't find the DataCon for a term" - Just dc -> do - clos <- trIO$ getClosureData a - let extra_args = length(dataConRepArgTys dc) - length(dataConOrigArgTys dc) - subTtypes = drop extra_args (dataConRepArgTys dc) - (subTtypesP, subTtypesNP) = partition isPointed subTtypes - - subTermsP <- mapM (\i->extractSubterm i (ptrs clos) - (subTtypesP!!(i-extra_args))) - [extra_args..extra_args + length subTtypesP - 1] - let unboxeds = extractUnboxed subTtypesNP (nonPtrs clos) - subTermsNP = map (uncurry Prim) (zip subTtypesNP unboxeds) - subTerms = reOrderTerms subTermsP subTermsNP subTtypes - resType <- liftM mkTyVarTy (newVar k) - baseType <- instScheme (dataConRepType dc) - let myType = mkFunTys (map (fromMaybe undefined . termType) - subTerms) - resType - addConstraint baseType myType - return (Term resType dc a subTerms) --- The otherwise case: can be a Thunk,AP,PAP,etc. - otherwise -> do - x <- liftM mkTyVarTy (newVar k) - return (Suspension ctype (Just x) a Nothing) - --- Access the array of pointers and recurse down. Needs to be done with --- care of no introducing a thunk! or go will fail to do its job - extractSubterm (I# i#) ptrs ty = case ptrs of - (Array _ _ ptrs#) -> case indexArray# ptrs# i# of - (# e #) -> go (typeKind ty) e - --- This is used to put together pointed and nonpointed subterms in the --- correct order. - reOrderTerms _ _ [] = [] - reOrderTerms pointed unpointed (ty:tys) - | isPointed ty = head pointed : reOrderTerms (tail pointed) unpointed tys - | otherwise = head unpointed : reOrderTerms pointed (tail unpointed) tys - -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 -> mapM zonkTcType ty >>= \ty -> - return (Suspension ct ty v b)} - -{- -Example of Type Reconstruction --------------------------------- -Suppose we have an existential type such as - -data Opaque = forall a. Opaque a - -And we have a term built as: - -t = Opaque (map Just [[1,1],[2,2]]) - -The type of t as far as the typechecker goes is t :: Opaque -If we seq the head of t, we obtain: - -t - O (_1::a) - -seq _1 () - -t - O ( (_3::b) : (_4::[b]) ) - -seq _3 () - -t - O ( (Just (_5::c)) : (_4::[b]) ) - -At this point, we know that b = (Maybe c) - -seq _5 () - -t - O ( (Just ((_6::d) : (_7::[d]) )) : (_4::[b]) ) - -At this point, we know that c = [d] - -seq _6 () - -t - O ( (Just (1 : (_7::[d]) )) : (_4::[b]) ) - -At this point, we know that d = Integer - -The fully reconstructed expressions, with propagation, would be: - -t - O ( (Just (_5::c)) : (_4::[Maybe c]) ) -t - O ( (Just ((_6::d) : (_7::[d]) )) : (_4::[Maybe [d]]) ) -t - O ( (Just (1 : (_7::[Integer]) )) : (_4::[Maybe [Integer]]) ) - - -For reference, the type of the thing inside the opaque is -map Just [[1,1],[2,2]] :: [Maybe [Integer]] - -NOTE: (Num t) contexts have been manually replaced by Integer for clarity --} - --------------------------------------------------------------------- --- The DataConEnv is used to store the addresses of datacons loaded --- via the dynamic linker --------------------------------------------------------------------- - -type DataConEnv = AddressEnv StgInfoTable - --- Note that this AddressEnv and DataConEnv I wrote trying to follow --- conventions in ghc, but probably they make no sense. Should --- probably be replaced by a plain Data.Map - -newtype AddressEnv a = AE {outAE::[(Ptr a, Name)]} - -emptyAddressEnv = AE [] - -extendAddressEnvList :: AddressEnv a -> [(Ptr a, Name)] -> AddressEnv a -extendAddressEnvList' :: AddressEnv a -> [(Ptr a, Name)] -> AddressEnv a -elemAddressEnv :: Ptr a -> AddressEnv a -> Bool -delFromAddressEnv :: AddressEnv a -> Ptr a -> AddressEnv a -nullAddressEnv :: AddressEnv a -> Bool -lookupAddressEnv :: AddressEnv a -> Ptr a -> Maybe Name - -extendAddressEnvList (AE env) = AE . nub . (++ env) -extendAddressEnvList' (AE env) = AE . (++ env) -elemAddressEnv ptr (AE env) = ptr `elem` fst (unzip env) -delFromAddressEnv (AE env) ptr = AE [(ptr', n) | (ptr', n) <- env, ptr' /= ptr] -nullAddressEnv = null . outAE -lookupAddressEnv (AE env) = flip lookup env - -instance Outputable (AddressEnv a) where - ppr (AE ae) = vcat [text (show ptr) <> comma <> ppr a | (ptr,a) <- ae] - - +----------------------------------------------------------------------------- +-- +-- 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("") + | 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 = "" + | t == stableNamePrimTyCon = "" + | t == statePrimTyCon = "" + | t == realWorldTyCon = "" + | t == threadIdPrimTyCon = "" + | t == weakPrimTyCon = "" + | t == arrayPrimTyCon = "" + | t == byteArrayPrimTyCon = "" + | t == mutableArrayPrimTyCon = "" + | t == mutableByteArrayPrimTyCon = "" + | t == mutVarPrimTyCon= "" + | t == mVarPrimTyCon = "" + | t == tVarPrimTyCon = "" + | 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: + + = + +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 + +