X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fghci%2FRtClosureInspect.hs;h=509eb996fc69743de88f6fee17a760916120e269;hp=e24b942560aa0e6291af3d68a42b9cf5df3e1421;hb=8c2fd74094dc533bf3256158325e3f091e57e5d2;hpb=644a71848125f89f0c8bd5ff2a359b86487428d1 diff --git a/compiler/ghci/RtClosureInspect.hs b/compiler/ghci/RtClosureInspect.hs index e24b942..509eb99 100644 --- a/compiler/ghci/RtClosureInspect.hs +++ b/compiler/ghci/RtClosureInspect.hs @@ -8,18 +8,17 @@ module RtClosureInspect( - cvObtainTerm, -- :: HscEnv -> Bool -> Maybe Type -> HValue -> IO Term - - ClosureType(..), - getClosureData, -- :: a -> IO Closure - Closure ( tipe, infoPtr, ptrs, nonPtrs ), - isConstr, -- :: ClosureType -> Bool - isIndirection, -- :: ClosureType -> Bool - - Term(..), - printTerm, - customPrintTerm, - customPrintTermBase, + cvObtainTerm, -- :: HscEnv -> Int -> Bool -> Maybe Type -> HValue -> IO Term + + Term(..), + isTerm, + isSuspension, + isPrim, + isNewtypeWrap, + pprTerm, + cPprTerm, + cPprTermBase, + CustomTermPrinter, termType, foldTerm, TermFold(..), @@ -28,101 +27,119 @@ module RtClosureInspect( isFullyEvaluated, isPointed, isFullyEvaluatedTerm, + mapTermType, + termTyVars, -- unsafeDeepSeq, + cvReconstructType, + improveRTTIType, + sigmaType, + Closure(..), + getClosureData, + ClosureType(..), + isConstr, + isIndirection ) where #include "HsVersions.h" import ByteCodeItbls ( StgInfoTable ) import qualified ByteCodeItbls as BCI( StgInfoTable(..) ) -import ByteCodeLink ( HValue ) import HscTypes ( HscEnv ) +import Linker -import DataCon -import Type -import TcRnMonad ( TcM, initTcPrintErrors, ioToTcRn, recoverM, writeMutVar ) +import DataCon +import Type +import Var +import TcRnMonad import TcType import TcMType import TcUnify -import TcGadt -import TyCon -import Var -import Name +import TcEnv +import DriverPhases +import TyCon +import Name import VarEnv -import OccName +import Util import VarSet -import {-#SOURCE#-} TcRnDriver ( tcRnRecoverDataCon ) -import TysPrim +import TysPrim import PrelNames import TysWiredIn -import Constants ( wORD_SIZE ) import Outputable -import Maybes +import FastString import Panic -import FiniteMap + +import Constants ( wORD_SIZE ) import GHC.Arr ( Array(..) ) -import GHC.Ptr ( Ptr(..), castPtr ) -import GHC.Exts -import GHC.Int ( Int32(..), Int64(..) ) -import GHC.Word ( Word32(..), Word64(..) ) +import GHC.Exts +import GHC.IOBase ( IO(IO) ) import Control.Monad import Data.Maybe import Data.Array.Base +import Data.Ix import Data.List ( partition ) -import Foreign.Storable - -import IO +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 +import System.IO --------------------------------------------- -- * 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 + , dc :: Either String DataCon + -- Carries a text representation if the datacon is + -- not exported by the .hi file, which is the case + -- for private constructors in -O0 compiled libraries , val :: HValue , subTerms :: [Term] } | Prim { ty :: Type - , value :: String } + , value :: [Word] } | Suspension { ctype :: ClosureType - , mb_ty :: Maybe Type + , ty :: Type , val :: HValue , bound_to :: Maybe Name -- Useful for printing } + | NewtypeWrap{ ty :: Type + , dc :: Either String DataCon + , wrapped_term :: Term } + | RefWrap { ty :: Type + , wrapped_term :: Term } +isTerm, isSuspension, isPrim, isNewtypeWrap :: Term -> Bool isTerm Term{} = True isTerm _ = False isSuspension Suspension{} = True isSuspension _ = False isPrim Prim{} = True isPrim _ = False +isNewtypeWrap NewtypeWrap{} = True +isNewtypeWrap _ = False -termType t@(Suspension {}) = mb_ty t -termType t = Just$ ty t +termType :: Term -> Type +termType t = ty t isFullyEvaluatedTerm :: Term -> Bool isFullyEvaluatedTerm Term {subTerms=tt} = all isFullyEvaluatedTerm tt -isFullyEvaluatedTerm Suspension {} = False isFullyEvaluatedTerm Prim {} = True +isFullyEvaluatedTerm NewtypeWrap{wrapped_term=t} = isFullyEvaluatedTerm t +isFullyEvaluatedTerm RefWrap{wrapped_term=t} = isFullyEvaluatedTerm t +isFullyEvaluatedTerm _ = False instance Outputable (Term) where - ppr = head . customPrintTerm customPrintTermBase + ppr t | Just doc <- cPprTerm cPprTermBase t = doc + | otherwise = panic "Outputable Term instance" ------------------------------------------------------------------------- -- Runtime Closure Datatype and functions for retrieving closure related stuff @@ -135,15 +152,15 @@ data ClosureType = Constr | AP | PAP | Indirection Int - | Other Int + | MutVar Int + | Other Int deriving (Show, Eq) data Closure = Closure { tipe :: ClosureType , infoPtr :: Ptr () , infoTable :: StgInfoTable , ptrs :: Array Int HValue - -- What would be the type here? HValue is ok? Should I build a Ptr? - , nonPtrs :: ByteArray# + , nonPtrs :: [Word] } instance Outputable ClosureType where @@ -151,6 +168,7 @@ instance Outputable ClosureType where #include "../includes/ClosureTypes.h" +aP_CODE, pAP_CODE :: Int aP_CODE = AP pAP_CODE = PAP #undef AP @@ -160,51 +178,73 @@ getClosureData :: a -> IO Closure getClosureData a = case unpackClosure# a of (# iptr, ptrs, nptrs #) -> do - itbl <- peek (Ptr iptr) + let iptr' + | ghciTablesNextToCode = + Ptr iptr + | otherwise = + -- the info pointer we get back from unpackClosure# + -- is to the beginning of the standard info table, + -- but the Storable instance for info tables takes + -- into account the extra entry pointer when + -- !ghciTablesNextToCode, so we must adjust here: + Ptr iptr `plusPtr` negate wORD_SIZE + itbl <- peek iptr' let tipe = readCType (BCI.tipe itbl) - elems = BCI.ptrs itbl - ptrsList = Array 0 (fromIntegral$ elems) ptrs - ptrsList `seq` return (Closure tipe (Ptr iptr) itbl ptrsList nptrs) + 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(elems >= 0) return () + ptrsList `seq` + return (Closure tipe (Ptr iptr) itbl ptrsList nptrs_data) readCType :: Integral a => a -> ClosureType -readCType i +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 && i < THUNK_SELECTOR = Thunk 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 + | i >= IND && i <= IND_STATIC = Indirection i' + | i' == aP_CODE = AP + | i == AP_STACK = AP + | i' == pAP_CODE = PAP + | i == MUT_VAR_CLEAN || i == MUT_VAR_DIRTY = MutVar i' + | otherwise = Other i' + where i' = 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 + _ -> 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] +amap' :: (t -> b) -> Array Int t -> [b] +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 + unsafeDeepSeq1 i a b -- 1st case avoids infinite loops for non reducible thunks | not (isConstr tipe) = seq a $! unsafeDeepSeq1 (i-1) a b -- | unsafePerformIO (isFullyEvaluated a) = b | otherwise = case unsafePerformIO (getClosureData a) of @@ -212,344 +252,417 @@ unsafeDeepSeq = unsafeDeepSeq1 2 where tipe = unsafePerformIO (getClosureType a) -} isPointed :: Type -> Bool -isPointed t | Just (t, _) <- splitTyConApp_maybe t = not$ isUnliftedTypeKind (tyConKind t) +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) +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) xx + = x : go tt rest + +sizeofTyCon :: TyCon -> Int -- in *words* +sizeofTyCon = primRepSizeW . tyConPrimRep ----------------------------------- -- * Traversals for Terms ----------------------------------- - -data TermFold a = TermFold { fTerm :: Type -> DataCon -> HValue -> [a] -> a - , fPrim :: Type -> String -> a - , fSuspension :: ClosureType -> Maybe Type -> HValue -> Maybe Name -> a +type TermProcessor a b = Type -> Either String DataCon -> HValue -> [a] -> b + +data TermFold a = TermFold { fTerm :: TermProcessor a a + , fPrim :: Type -> [Word] -> a + , fSuspension :: ClosureType -> Type -> HValue + -> Maybe Name -> a + , fNewtypeWrap :: Type -> Either String DataCon + -> a -> a + , fRefWrap :: Type -> a -> 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 +foldTerm tf (NewtypeWrap ty dc t) = fNewtypeWrap tf ty dc (foldTerm tf t) +foldTerm tf (RefWrap ty t) = fRefWrap tf ty (foldTerm tf t) idTermFold :: TermFold Term idTermFold = TermFold { fTerm = Term, fPrim = Prim, - fSuspension = Suspension + fSuspension = Suspension, + fNewtypeWrap = NewtypeWrap, + fRefWrap = RefWrap } 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 + fSuspension = (((return.).).). Suspension, + fNewtypeWrap= \ty dc t -> NewtypeWrap ty dc `liftM` t, + fRefWrap = \ty t -> RefWrap ty `liftM` t } +mapTermType :: (Type -> Type) -> Term -> Term +mapTermType f = foldTerm idTermFold { + fTerm = \ty dc hval tt -> Term (f ty) dc hval tt, + fSuspension = \ct ty hval n -> + Suspension ct (f ty) hval n, + fNewtypeWrap= \ty dc t -> NewtypeWrap (f ty) dc t, + fRefWrap = \ty t -> RefWrap (f ty) t} + +termTyVars :: Term -> TyVarSet +termTyVars = foldTerm TermFold { + fTerm = \ty _ _ tt -> + tyVarsOfType ty `plusVarEnv` concatVarEnv tt, + fSuspension = \_ ty _ _ -> tyVarsOfType ty, + fPrim = \ _ _ -> emptyVarEnv, + fNewtypeWrap= \ty _ t -> tyVarsOfType ty `plusVarEnv` t, + fRefWrap = \ty t -> tyVarsOfType ty `plusVarEnv` t} + where concatVarEnv = foldr plusVarEnv emptyVarEnv + ---------------------------------- -- 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} - | Just _ <- splitFunTy_maybe ty = text "" - | otherwise = 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 :: forall m. Monad m => ((Int->Term->m SDoc)->[Term->m (Maybe SDoc)]) -> Term -> m SDoc -customPrintTerm custom = go 0 where --- go :: Monad m => Int -> Term -> m SDoc - go prec t@Term{subTerms=tt, dc=dc} = do - let mb_customDocs = map ($t) (custom go) :: [m (Maybe SDoc)] - first_success <- firstJustM mb_customDocs - case first_success of - Just doc -> return$ 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 +type Precedence = Int +type TermPrinter = Precedence -> Term -> SDoc +type TermPrinterM m = Precedence -> Term -> m SDoc + +app_prec,cons_prec, max_prec ::Int +max_prec = 10 +app_prec = max_prec +cons_prec = 5 -- TODO Extract this info from GHC itself + +pprTerm :: TermPrinter -> TermPrinter +pprTerm y p t | Just doc <- pprTermM (\p -> Just . y p) p t = doc +pprTerm _ _ _ = panic "pprTerm" + +pprTermM, ppr_termM, pprNewtypeWrap :: Monad m => TermPrinterM m -> TermPrinterM m +pprTermM y p t = pprDeeper `liftM` ppr_termM y p t + +ppr_termM y p Term{dc=Left dc_tag, subTerms=tt} = do + tt_docs <- mapM (y app_prec) tt + return$ cparen (not(null tt) && p >= app_prec) (text dc_tag <+> pprDeeperList fsep tt_docs) + +ppr_termM y p Term{dc=Right dc, subTerms=tt} +{- | dataConIsInfix dc, (t1:t2:tt') <- tt --TODO fixity + = parens (ppr_term1 True t1 <+> ppr dc <+> ppr_term1 True ppr t2) + <+> hsep (map (ppr_term1 True) tt) +-} -- TODO Printing infix constructors properly + | null tt = return$ ppr dc + | otherwise = do + tt_docs <- mapM (y app_prec) tt + return$ cparen (p >= app_prec) (ppr dc <+> pprDeeperList fsep tt_docs) + +ppr_termM y p t@NewtypeWrap{} = pprNewtypeWrap y p t +ppr_termM y p RefWrap{wrapped_term=t} = do + contents <- y app_prec t + return$ cparen (p >= app_prec) (text "GHC.Prim.MutVar#" <+> contents) + -- The constructor name is wired in here ^^^ for the sake of simplicity. + -- I don't think mutvars are going to change in a near future. + -- In any case this is solely a presentation matter: MutVar# is + -- a datatype with no constructors, implemented by the RTS + -- (hence there is no way to obtain a datacon and print it). +ppr_termM _ _ t = ppr_termM1 t + + +ppr_termM1 :: Monad m => Term -> m SDoc +ppr_termM1 Prim{value=words, ty=ty} = + return$ text$ repPrim (tyConAppTyCon ty) words +ppr_termM1 Suspension{bound_to=Nothing} = return$ char '_' +ppr_termM1 Suspension{ty=ty, bound_to=Just n} + | Just _ <- splitFunTy_maybe ty = return$ ptext (sLit "") + | otherwise = return$ parens$ ppr n <> text "::" <> ppr ty +ppr_termM1 Term{} = panic "ppr_termM1 - Term" +ppr_termM1 RefWrap{} = panic "ppr_termM1 - RefWrap" +ppr_termM1 NewtypeWrap{} = panic "ppr_termM1 - NewtypeWrap" + +pprNewtypeWrap y p NewtypeWrap{ty=ty, wrapped_term=t} + | Just (tc,_) <- splitNewTyConApp_maybe ty + , ASSERT(isNewTyCon tc) True + , Just new_dc <- tyConSingleDataCon_maybe tc = do + real_term <- y max_prec t + return$ cparen (p >= app_prec) (ppr new_dc <+> real_term) +pprNewtypeWrap _ _ _ = panic "pprNewtypeWrap" + +------------------------------------------------------- +-- Custom Term Pretty Printers +------------------------------------------------------- + +-- We can want to customize the representation of a +-- term depending on its type. +-- However, note that custom printers have to work with +-- type representations, instead of directly with types. +-- We cannot use type classes here, unless we employ some +-- typerep trickery (e.g. Weirich's RepLib tricks), +-- which I didn't. Therefore, this code replicates a lot +-- of what type classes provide for free. + +type CustomTermPrinter m = TermPrinterM m + -> [Precedence -> Term -> (m (Maybe SDoc))] + +-- | 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 :: Monad m => CustomTermPrinter m -> Term -> m SDoc +cPprTerm printers_ = go 0 where + printers = printers_ go + go prec t = do + let default_ = Just `liftM` pprTermM go prec t + mb_customDocs = [pp prec t | pp <- printers] ++ [default_] + Just doc <- firstJustM mb_customDocs + return$ cparen (prec>app_prec+1) doc + firstJustM (mb:mbs) = mb >>= maybe (firstJustM mbs) (return . Just) firstJustM [] = return Nothing -customPrintTermBase :: Monad m => (Int->Term-> m SDoc)->[Term->m (Maybe SDoc)] -customPrintTermBase showP = - [ - test isTupleDC (liftM (parens . hcat . 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 = 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 (hcat (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=[]} = [] +-- Default set of custom printers. Note that the recursion knot is explicit +cPprTermBase :: Monad m => CustomTermPrinter m +cPprTermBase y = + [ ifTerm (isTupleTy.ty) (\_p -> liftM (parens . hcat . punctuate comma) + . mapM (y (-1)) + . subTerms) + , ifTerm (\t -> isTyCon listTyCon (ty t) && subTerms t `lengthIs` 2) + (\ p Term{subTerms=[h,t]} -> doList p h t) + , ifTerm (isTyCon intTyCon . ty) (coerceShow$ \(a::Int)->a) + , ifTerm (isTyCon charTyCon . ty) (coerceShow$ \(a::Char)->a) + , ifTerm (isTyCon floatTyCon . ty) (coerceShow$ \(a::Float)->a) + , ifTerm (isTyCon doubleTyCon . ty) (coerceShow$ \(a::Double)->a) + , ifTerm (isIntegerTy . ty) (coerceShow$ \(a::Integer)->a) + ] + where ifTerm pred f prec t@Term{} + | pred t = Just `liftM` f prec t + ifTerm _ _ _ _ = return Nothing + + isIntegerTy ty = fromMaybe False $ do + (tc,_) <- splitTyConApp_maybe ty + return (tyConName tc == integerTyConName) + + isTupleTy ty = fromMaybe False $ do + (tc,_) <- splitTyConApp_maybe ty + return (tc `elem` (fst.unzip.elems) boxedTupleArr) + + isTyCon a_tc ty = fromMaybe False $ do + (tc,_) <- splitTyConApp_maybe ty + return (a_tc == tc) + + coerceShow f _p = return . text . show . f . unsafeCoerce# . val + + --Note pprinting of list terms is not lazy + doList p h t = do + let elems = h : getListTerms t + isConsLast = not(termType(last elems) `coreEqType` termType h) + print_elems <- mapM (y cons_prec) elems + return$ if isConsLast + then cparen (p >= cons_prec) + . pprDeeperList fsep + . punctuate (space<>colon) + $ print_elems + else brackets (pprDeeperList fcat$ + punctuate comma print_elems) + + where getListTerms Term{subTerms=[h,t]} = h : getListTerms t + getListTerms 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 Term -> IO Term +runTR :: HscEnv -> TR a -> IO a runTR hsc_env c = do - mb_term <- initTcPrintErrors hsc_env iNTERACTIVE (c >>= zonkTerm) + mb_term <- runTR_maybe hsc_env c 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 >>= uncurry unifyType - -{- - 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 = go True - where - go rewriteRHS lhs rhs - -- TyVar lhs inductive case - | Just tv <- getTyVar_maybe lhs - = recoverM (return (lhs,rhs)) $ do - Indirect ty_v <- readMetaTyVar tv - (lhs', rhs') <- go rewriteRHS ty_v rhs - writeMutVar (metaTvRef tv) (Indirect lhs') - return (lhs, rhs') - -- TyVar rhs inductive case - | Just tv <- getTyVar_maybe rhs - = recoverM (return (lhs,rhs)) $ do - Indirect ty_v <- readMetaTyVar tv - (lhs', rhs') <- go rewriteRHS lhs ty_v - writeMutVar (metaTvRef tv) (Indirect rhs') - return (lhs', rhs) --- FunTy inductive case - | Just (l1,l2) <- splitFunTy_maybe lhs - , Just (r1,r2) <- splitFunTy_maybe rhs - = do (l2',r2') <- go True l2 r2 - (l1',r1') <- go False 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 = do - - let (tycon_l',args_l') = if isNewTyCon tycon_r && not(isNewTyCon tycon_l) - then (tycon_r, rewrite tycon_r lhs) - else (tycon_l, args_l) - (tycon_r',args_r') = if rewriteRHS && isNewTyCon tycon_l && not(isNewTyCon tycon_r) - then (tycon_l, rewrite tycon_l rhs) - else (tycon_r, args_r) - (args_l'', args_r'') <- unzip `liftM` zipWithM (go rewriteRHS) args_l' args_r' - return (mkTyConApp tycon_l' args_l'', mkTyConApp tycon_r' args_r'') + Just x -> return x - | otherwise = return (lhs,rhs) +runTR_maybe :: HscEnv -> TR a -> IO (Maybe a) +runTR_maybe hsc_env = fmap snd . initTc hsc_env HsSrcFile False iNTERACTIVE - where rewrite newtyped_tc lame_tipe - | (tvs, tipe) <- newTyConRep newtyped_tc - = case tcUnifyTys (const BindMe) [tipe] [lame_tipe] of - Just subst -> substTys subst (map mkTyVarTy tvs) - otherwise -> panic "congruenceNewtypes: Can't unify a newtype" +traceTR :: SDoc -> TR () +traceTR = liftTcM . traceTc -newVar :: Kind -> TR TcTyVar -newVar = liftTcM . newFlexiTyVar +trIO :: IO a -> TR a +trIO = liftTcM . liftIO +liftTcM :: TcM a -> TR a 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 = do - -- Obtain the term and tidy the type before returning it - term <- cvObtainTerm1 hsc_env force mb_ty a - return $ tidyTypes term - 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 = runTR hsc_env $ do - tv <- case (isMonomorphic `fmap` mb_ty) of - Just True -> return (fromJust mb_ty) - _ -> do - tv_ <- liftM mkTyVarTy (newVar argTypeKind) - when (isJust mb_ty) $ - instScheme (sigmaType$ fromJust mb_ty) >>= addConstraint tv_ - return tv_ - go tv (fromMaybe tv mb_ty) hval +newVar :: Kind -> TR TcType +newVar = liftTcM . fmap mkTyVarTy . newBoxyTyVar + +-- | 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 boxyUnify + >> 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 + >>= return . expandNewtypes + Just ty | isMonomorphic ty -> go bound ty ty hval + >>= zonkTerm + >>= return . expandNewtypes + Just ty -> do + (ty',rev_subst) <- instScheme (sigmaType ty) + addConstraint tv ty' + term <- go bound tv tv hval >>= zonkTerm + --restore original Tyvars + return$ expandNewtypes $ mapTermType (substTy rev_subst) term where - go 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 + go bound _ _ _ | seq bound False = undefined + go 0 tv _ty a = do + clos <- trIO $ getClosureData a + return (Suspension (tipe clos) 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 - Thunk _ | force -> seq a $ go tv ty a +-- 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 tv ty $! (ptrs clos ! 0) + Indirection _ -> go bound tv ty $! (ptrs clos ! 0) +-- We also follow references + MutVar _ | Just (tycon,[world,ty_contents]) <- splitTyConApp_maybe ty + -- , tycon == mutVarPrimTyCon + -> do + contents <- trIO$ IO$ \w -> readMutVar# (unsafeCoerce# a) w + tv' <- newVar liftedTypeKind + addConstraint tv (mkTyConApp tycon [world,tv']) + x <- go bound tv' ty_contents contents + return (RefWrap ty x) + -- The interesting case Constr -> do - m_dc <- trIO$ tcRnRecoverDataCon hsc_env (infoPtr clos) - case m_dc of - Nothing -> panic "Can't find the DataCon for a term" + 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) + 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 (mkTyVarTy `fmap` newVar k) + [ 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. + -- 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 - instScheme(dataConRepType dc) >>= addConstraint myType - subTermsP <- sequence $ drop extra_args -- all extra arguments are pointed - [ appArr (go tv t) (ptrs clos) i + 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 (nonPtrs clos) + let unboxeds = extractUnboxed subTtypesNP clos subTermsNP = map (uncurry Prim) (zip subTtypesNP unboxeds) - subTerms = reOrderTerms subTermsP subTermsNP (drop extra_args subTtypes) - return (Term tv dc a subTerms) + 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. - otherwise -> - return (Suspension (tipe clos) (Just tv) 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 - appArr f arr (I# i#) = case arr of - (Array _ _ ptrs#) -> case indexArray# ptrs# i# of - (# e #) -> f e + tipe_clos -> + return (Suspension tipe_clos tv a Nothing) matchSubTypes dc ty | Just (_,ty_args) <- splitTyConApp_maybe (repType ty) - , null (dataConExTyVars dc) --TODO Handle the case of extra existential tyvars +-- 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 @@ -557,74 +670,227 @@ cvObtainTerm1 hsc_env force mb_ty hval = runTR hsc_env $ do 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 + , ptext (sLit "reOrderTerms") $$ + (ppr pointed $$ ppr unpointed)) + let (t:tt) = pointed in t : reOrderTerms tt unpointed tys | otherwise = ASSERT2(not(null unpointed) - , ptext SLIT("reOrderTerms") $$ (ppr pointed $$ ppr unpointed)) - head unpointed : reOrderTerms pointed (tail unpointed) tys + , ptext (sLit "reOrderTerms") $$ + (ppr pointed $$ ppr unpointed)) + let (t:tt) = unpointed in t : reOrderTerms pointed tt tys + + expandNewtypes t@Term{ ty=ty, subTerms=tt } + | Just (tc, args) <- splitNewTyConApp_maybe ty + , isNewTyCon tc + , wrapped_type <- newTyConInstRhs tc args + , Just dc <- tyConSingleDataCon_maybe tc + , t' <- expandNewtypes t{ ty = wrapped_type + , subTerms = map expandNewtypes tt } + = NewtypeWrap ty (Right dc) t' + + | otherwise = t{ subTerms = map expandNewtypes tt } + + expandNewtypes t = t + + +-- Fast, breadth-first Type reconstruction +cvReconstructType :: HscEnv -> Int -> Maybe Type -> HValue -> IO (Maybe Type) +cvReconstructType hsc_env max_depth 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 _ _ _ 0 = traceTR (text "Failed to reconstruct a type after " <> + int max_depth <> text " steps") + search stop expand l d = + case viewl l of + EmptyL -> return () + x :< xx -> 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 $! (ptrs clos ! 0) + MutVar _ -> do + contents <- trIO$ IO$ \w -> readMutVar# (unsafeCoerce# a) w + tv' <- newVar liftedTypeKind + world <- newVar liftedTypeKind + addConstraint tv (mkTyConApp mutVarPrimTyCon [world,tv']) +-- x <- go tv' ty_contents contents + return [(tv', contents)] + Constr -> do + Right dcname <- dataConInfoPtrToName (infoPtr clos) + (_,mb_dc) <- tryTcErrs (tcLookupDataCon dcname) + case mb_dc of + Nothing-> do + -- TODO: Check this case + 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)] + _ -> return [] + +-- Compute the difference between a base type and the type found by RTTI +-- improveType +-- The types can contain skolem type variables, which need to be treated as normal vars. +-- In particular, we want them to unify with things. +improveRTTIType :: HscEnv -> Type -> Type -> IO (Maybe TvSubst) +improveRTTIType hsc_env ty rtti_ty = runTR_maybe hsc_env $ do + let (_,ty0) = splitForAllTys ty + ty_tvs = varSetElems $ tyVarsOfType ty0 + let (_,rtti_ty0)= splitForAllTys rtti_ty + rtti_tvs = varSetElems $ tyVarsOfType rtti_ty0 + (ty_tvs',_,ty')<- tcInstType (mapM tcInstTyVar) (mkSigmaTy ty_tvs [] ty0) + (_,_,rtti_ty') <- tcInstType (mapM tcInstTyVar) (mkSigmaTy rtti_tvs [] rtti_ty0) + boxyUnify rtti_ty' ty' + tvs1_contents <- zonkTcTyVars ty_tvs' + let subst = uncurry zipTopTvSubst + (unzip [(tv,ty) | tv <- ty_tvs, ty <- tvs1_contents + , getTyVar_maybe ty /= Just tv + , not(isTyVarTy ty)]) +-- liftIO $ hPutStrLn stderr $ showSDocDebug $ text "unify " <+> sep [ppr ty, ppr rtti_ty, equals, ppr subst ] + return subst + +-- Dealing with newtypes +{- + congruenceNewtypes does 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 sometimes there is evidence available. + Evidence can come from DataCon signatures or + from compile-time type inference. + What we are doing here is an approximation + of unification modulo a set of equations derived + from newtype definitions. These equations should be the + same as the equality coercions generated for newtypes + in System Fc. The idea is to perform a sort of rewriting, + taking those equations as rules, before launching unification. + + The caller must ensure the following. + The 1st type (lhs) comes from the heap structure of ptrs,nptrs. + The 2nd type (rhs) comes from a DataCon type signature. + Rewriting (i.e. adding/removing a newtype wrapper) can happen + in both types, but in the rhs it is restricted to the result type. -isMonomorphic = isEmptyVarSet . tyVarsOfType + Note that it is very tricky to make this 'rewriting' + work with the unification implemented by TcM, where + substitutions are operationally inlined. The order in which + constraints are unified is vital as we cannot modify + anything that has been touched by a previous unification step. +Therefore, congruenceNewtypes is sound only if the types +recovered by the RTTI mechanism are unified Top-Down. +-} +congruenceNewtypes :: TcType -> TcType -> TR (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, _) <- splitNewTyConApp_maybe lhs + , Just (tycon_r, _) <- splitNewTyConApp_maybe rhs + , tycon_l /= tycon_r + = do rhs' <- upgrade tycon_l rhs + return (lhs, rhs') + + | otherwise = return (lhs,rhs) + + where upgrade :: TyCon -> Type -> TR Type + upgrade new_tycon ty + | not (isNewTyCon new_tycon) = return ty + | otherwise = do + vars <- mapM (newVar . tyVarKind) (tyConTyVars new_tycon) + let ty' = mkTyConApp new_tycon vars + liftTcM (unifyType ty (repType ty')) + -- assumes that reptype doesn't ^^^^ touch tyconApp args + return ty' + + +-------------------------------------------------------------------------------- +-- Semantically different to recoverM in TcRnMonad +-- recoverM retains the errors in the first action, +-- whereas recoverTc here does not +recoverTc :: TcM a -> TcM a -> TcM a +recoverTc recover thing = do + (_,mb_res) <- tryTcErrs thing + case mb_res of + Nothing -> recover + Just res -> return res + +isMonomorphic :: Type -> Bool +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 + where + mapMif_ _ _ [] = [] + mapMif_ pred f (x:xx) = (if pred x then f x else return x) : mapMif_ pred f xx + +unlessM :: Monad m => m Bool -> m () -> m () +unlessM condM acc = condM >>= \c -> unless c acc + +-- Strict application of f at index i +appArr :: Ix i => (e -> a) -> Array i e -> Int -> a +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)} + ,fSuspension = \ct ty v b -> zonkTcType ty >>= \ty -> + return (Suspension ct ty v b) + ,fNewtypeWrap= \ty dc t -> + return NewtypeWrap `ap` zonkTcType ty `ap` return dc `ap` t} -- Is this defined elsewhere? -- Generalize the type: find all free tyvars and wrap in the appropiate ForAll. +sigmaType :: Type -> Type sigmaType ty = mkForAllTys (varSetElems$ tyVarsOfType (dropForAlls ty)) ty -{- -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 --}