Remove code that is dead now that we need >= 6.12 to build
[ghc.git] / compiler / ghci / RtClosureInspect.hs
1 -----------------------------------------------------------------------------
2 --
3 -- GHC Interactive support for inspecting arbitrary closures at runtime
4 --
5 -- Pepe Iborra (supported by Google SoC) 2006
6 --
7 -----------------------------------------------------------------------------
8
9 module RtClosureInspect(
10 cvObtainTerm, -- :: HscEnv -> Int -> Bool -> Maybe Type -> HValue -> IO Term
11 cvReconstructType,
12 improveRTTIType,
13
14 Term(..),
15 isTerm, isSuspension, isPrim, isFun, isFunLike, isNewtypeWrap,
16 isFullyEvaluated, isFullyEvaluatedTerm,
17 termType, mapTermType, termTyVars,
18 foldTerm, TermFold(..), foldTermM, TermFoldM(..), idTermFold,
19 pprTerm, cPprTerm, cPprTermBase, CustomTermPrinter,
20
21 -- unsafeDeepSeq,
22
23 Closure(..), getClosureData, ClosureType(..), isConstr, isIndirection
24 ) where
25
26 #include "HsVersions.h"
27
28 import ByteCodeItbls ( StgInfoTable )
29 import qualified ByteCodeItbls as BCI( StgInfoTable(..) )
30 import HscTypes
31 import Linker
32
33 import DataCon
34 import Type
35 import qualified Unify as U
36 import TypeRep -- I know I know, this is cheating
37 import Var
38 import TcRnMonad
39 import TcType
40 import TcMType
41 import TcUnify
42 import TcEnv
43
44 import TyCon
45 import Name
46 import VarEnv
47 import Util
48 import ListSetOps
49 import VarSet
50 import TysPrim
51 import PrelNames
52 import TysWiredIn
53 import DynFlags
54 import Outputable
55 import FastString
56 -- import Panic
57
58 import Constants ( wORD_SIZE )
59
60 import GHC.Arr ( Array(..) )
61 import GHC.Exts
62 import GHC.IO ( IO(..) )
63
64 import Control.Monad
65 import Data.Maybe
66 import Data.Array.Base
67 import Data.Ix
68 import Data.List
69 import qualified Data.Sequence as Seq
70 import Data.Monoid
71 import Data.Sequence (viewl, ViewL(..))
72 import Foreign hiding (unsafePerformIO)
73 import System.IO.Unsafe
74
75 ---------------------------------------------
76 -- * A representation of semi evaluated Terms
77 ---------------------------------------------
78
79 data Term = Term { ty :: RttiType
80 , dc :: Either String DataCon
81 -- Carries a text representation if the datacon is
82 -- not exported by the .hi file, which is the case
83 -- for private constructors in -O0 compiled libraries
84 , val :: HValue
85 , subTerms :: [Term] }
86
87 | Prim { ty :: RttiType
88 , value :: [Word] }
89
90 | Suspension { ctype :: ClosureType
91 , ty :: RttiType
92 , val :: HValue
93 , bound_to :: Maybe Name -- Useful for printing
94 }
95 | NewtypeWrap{ -- At runtime there are no newtypes, and hence no
96 -- newtype constructors. A NewtypeWrap is just a
97 -- made-up tag saying "heads up, there used to be
98 -- a newtype constructor here".
99 ty :: RttiType
100 , dc :: Either String DataCon
101 , wrapped_term :: Term }
102 | RefWrap { -- The contents of a reference
103 ty :: RttiType
104 , wrapped_term :: Term }
105
106 isTerm, isSuspension, isPrim, isFun, isFunLike, isNewtypeWrap :: Term -> Bool
107 isTerm Term{} = True
108 isTerm _ = False
109 isSuspension Suspension{} = True
110 isSuspension _ = False
111 isPrim Prim{} = True
112 isPrim _ = False
113 isNewtypeWrap NewtypeWrap{} = True
114 isNewtypeWrap _ = False
115
116 isFun Suspension{ctype=Fun} = True
117 isFun _ = False
118
119 isFunLike s@Suspension{ty=ty} = isFun s || isFunTy ty
120 isFunLike _ = False
121
122 termType :: Term -> RttiType
123 termType t = ty t
124
125 isFullyEvaluatedTerm :: Term -> Bool
126 isFullyEvaluatedTerm Term {subTerms=tt} = all isFullyEvaluatedTerm tt
127 isFullyEvaluatedTerm Prim {} = True
128 isFullyEvaluatedTerm NewtypeWrap{wrapped_term=t} = isFullyEvaluatedTerm t
129 isFullyEvaluatedTerm RefWrap{wrapped_term=t} = isFullyEvaluatedTerm t
130 isFullyEvaluatedTerm _ = False
131
132 instance Outputable (Term) where
133 ppr t | Just doc <- cPprTerm cPprTermBase t = doc
134 | otherwise = panic "Outputable Term instance"
135
136 -------------------------------------------------------------------------
137 -- Runtime Closure Datatype and functions for retrieving closure related stuff
138 -------------------------------------------------------------------------
139 data ClosureType = Constr
140 | Fun
141 | Thunk Int
142 | ThunkSelector
143 | Blackhole
144 | AP
145 | PAP
146 | Indirection Int
147 | MutVar Int
148 | MVar Int
149 | Other Int
150 deriving (Show, Eq)
151
152 data Closure = Closure { tipe :: ClosureType
153 , infoPtr :: Ptr ()
154 , infoTable :: StgInfoTable
155 , ptrs :: Array Int HValue
156 , nonPtrs :: [Word]
157 }
158
159 instance Outputable ClosureType where
160 ppr = text . show
161
162 #include "../includes/rts/storage/ClosureTypes.h"
163
164 aP_CODE, pAP_CODE :: Int
165 aP_CODE = AP
166 pAP_CODE = PAP
167 #undef AP
168 #undef PAP
169
170 getClosureData :: a -> IO Closure
171 getClosureData a =
172 case unpackClosure# a of
173 (# iptr, ptrs, nptrs #) -> do
174 let iptr'
175 | ghciTablesNextToCode =
176 Ptr iptr
177 | otherwise =
178 -- the info pointer we get back from unpackClosure#
179 -- is to the beginning of the standard info table,
180 -- but the Storable instance for info tables takes
181 -- into account the extra entry pointer when
182 -- !ghciTablesNextToCode, so we must adjust here:
183 Ptr iptr `plusPtr` negate wORD_SIZE
184 itbl <- peek iptr'
185 let tipe = readCType (BCI.tipe itbl)
186 elems = fromIntegral (BCI.ptrs itbl)
187 ptrsList = Array 0 (elems - 1) elems ptrs
188 nptrs_data = [W# (indexWordArray# nptrs i)
189 | I# i <- [0.. fromIntegral (BCI.nptrs itbl)] ]
190 ASSERT(elems >= 0) return ()
191 ptrsList `seq`
192 return (Closure tipe (Ptr iptr) itbl ptrsList nptrs_data)
193
194 readCType :: Integral a => a -> ClosureType
195 readCType i
196 | i >= CONSTR && i <= CONSTR_NOCAF_STATIC = Constr
197 | i >= FUN && i <= FUN_STATIC = Fun
198 | i >= THUNK && i < THUNK_SELECTOR = Thunk i'
199 | i == THUNK_SELECTOR = ThunkSelector
200 | i == BLACKHOLE = Blackhole
201 | i >= IND && i <= IND_STATIC = Indirection i'
202 | i' == aP_CODE = AP
203 | i == AP_STACK = AP
204 | i' == pAP_CODE = PAP
205 | i == MUT_VAR_CLEAN || i == MUT_VAR_DIRTY= MutVar i'
206 | i == MVAR_CLEAN || i == MVAR_DIRTY = MVar i'
207 | otherwise = Other i'
208 where i' = fromIntegral i
209
210 isConstr, isIndirection, isThunk :: ClosureType -> Bool
211 isConstr Constr = True
212 isConstr _ = False
213
214 isIndirection (Indirection _) = True
215 isIndirection _ = False
216
217 isThunk (Thunk _) = True
218 isThunk ThunkSelector = True
219 isThunk AP = True
220 isThunk _ = False
221
222 isFullyEvaluated :: a -> IO Bool
223 isFullyEvaluated a = do
224 closure <- getClosureData a
225 case tipe closure of
226 Constr -> do are_subs_evaluated <- amapM isFullyEvaluated (ptrs closure)
227 return$ and are_subs_evaluated
228 _ -> return False
229 where amapM f = sequence . amap' f
230
231 -- TODO: Fix it. Probably the otherwise case is failing, trace/debug it
232 {-
233 unsafeDeepSeq :: a -> b -> b
234 unsafeDeepSeq = unsafeDeepSeq1 2
235 where unsafeDeepSeq1 0 a b = seq a $! b
236 unsafeDeepSeq1 i a b -- 1st case avoids infinite loops for non reducible thunks
237 | not (isConstr tipe) = seq a $! unsafeDeepSeq1 (i-1) a b
238 -- | unsafePerformIO (isFullyEvaluated a) = b
239 | otherwise = case unsafePerformIO (getClosureData a) of
240 closure -> foldl' (flip unsafeDeepSeq) b (ptrs closure)
241 where tipe = unsafePerformIO (getClosureType a)
242 -}
243
244 -----------------------------------
245 -- * Traversals for Terms
246 -----------------------------------
247 type TermProcessor a b = RttiType -> Either String DataCon -> HValue -> [a] -> b
248
249 data TermFold a = TermFold { fTerm :: TermProcessor a a
250 , fPrim :: RttiType -> [Word] -> a
251 , fSuspension :: ClosureType -> RttiType -> HValue
252 -> Maybe Name -> a
253 , fNewtypeWrap :: RttiType -> Either String DataCon
254 -> a -> a
255 , fRefWrap :: RttiType -> a -> a
256 }
257
258
259 data TermFoldM m a =
260 TermFoldM {fTermM :: TermProcessor a (m a)
261 , fPrimM :: RttiType -> [Word] -> m a
262 , fSuspensionM :: ClosureType -> RttiType -> HValue
263 -> Maybe Name -> m a
264 , fNewtypeWrapM :: RttiType -> Either String DataCon
265 -> a -> m a
266 , fRefWrapM :: RttiType -> a -> m a
267 }
268
269 foldTerm :: TermFold a -> Term -> a
270 foldTerm tf (Term ty dc v tt) = fTerm tf ty dc v (map (foldTerm tf) tt)
271 foldTerm tf (Prim ty v ) = fPrim tf ty v
272 foldTerm tf (Suspension ct ty v b) = fSuspension tf ct ty v b
273 foldTerm tf (NewtypeWrap ty dc t) = fNewtypeWrap tf ty dc (foldTerm tf t)
274 foldTerm tf (RefWrap ty t) = fRefWrap tf ty (foldTerm tf t)
275
276
277 foldTermM :: Monad m => TermFoldM m a -> Term -> m a
278 foldTermM tf (Term ty dc v tt) = mapM (foldTermM tf) tt >>= fTermM tf ty dc v
279 foldTermM tf (Prim ty v ) = fPrimM tf ty v
280 foldTermM tf (Suspension ct ty v b) = fSuspensionM tf ct ty v b
281 foldTermM tf (NewtypeWrap ty dc t) = foldTermM tf t >>= fNewtypeWrapM tf ty dc
282 foldTermM tf (RefWrap ty t) = foldTermM tf t >>= fRefWrapM tf ty
283
284 idTermFold :: TermFold Term
285 idTermFold = TermFold {
286 fTerm = Term,
287 fPrim = Prim,
288 fSuspension = Suspension,
289 fNewtypeWrap = NewtypeWrap,
290 fRefWrap = RefWrap
291 }
292
293 mapTermType :: (RttiType -> Type) -> Term -> Term
294 mapTermType f = foldTerm idTermFold {
295 fTerm = \ty dc hval tt -> Term (f ty) dc hval tt,
296 fSuspension = \ct ty hval n ->
297 Suspension ct (f ty) hval n,
298 fNewtypeWrap= \ty dc t -> NewtypeWrap (f ty) dc t,
299 fRefWrap = \ty t -> RefWrap (f ty) t}
300
301 mapTermTypeM :: Monad m => (RttiType -> m Type) -> Term -> m Term
302 mapTermTypeM f = foldTermM TermFoldM {
303 fTermM = \ty dc hval tt -> f ty >>= \ty' -> return $ Term ty' dc hval tt,
304 fPrimM = (return.) . Prim,
305 fSuspensionM = \ct ty hval n ->
306 f ty >>= \ty' -> return $ Suspension ct ty' hval n,
307 fNewtypeWrapM= \ty dc t -> f ty >>= \ty' -> return $ NewtypeWrap ty' dc t,
308 fRefWrapM = \ty t -> f ty >>= \ty' -> return $ RefWrap ty' t}
309
310 termTyVars :: Term -> TyVarSet
311 termTyVars = foldTerm TermFold {
312 fTerm = \ty _ _ tt ->
313 tyVarsOfType ty `plusVarEnv` concatVarEnv tt,
314 fSuspension = \_ ty _ _ -> tyVarsOfType ty,
315 fPrim = \ _ _ -> emptyVarEnv,
316 fNewtypeWrap= \ty _ t -> tyVarsOfType ty `plusVarEnv` t,
317 fRefWrap = \ty t -> tyVarsOfType ty `plusVarEnv` t}
318 where concatVarEnv = foldr plusVarEnv emptyVarEnv
319
320 ----------------------------------
321 -- Pretty printing of terms
322 ----------------------------------
323
324 type Precedence = Int
325 type TermPrinter = Precedence -> Term -> SDoc
326 type TermPrinterM m = Precedence -> Term -> m SDoc
327
328 app_prec,cons_prec, max_prec ::Int
329 max_prec = 10
330 app_prec = max_prec
331 cons_prec = 5 -- TODO Extract this info from GHC itself
332
333 pprTerm :: TermPrinter -> TermPrinter
334 pprTerm y p t | Just doc <- pprTermM (\p -> Just . y p) p t = doc
335 pprTerm _ _ _ = panic "pprTerm"
336
337 pprTermM, ppr_termM, pprNewtypeWrap :: Monad m => TermPrinterM m -> TermPrinterM m
338 pprTermM y p t = pprDeeper `liftM` ppr_termM y p t
339
340 ppr_termM y p Term{dc=Left dc_tag, subTerms=tt} = do
341 tt_docs <- mapM (y app_prec) tt
342 return$ cparen (not(null tt) && p >= app_prec) (text dc_tag <+> pprDeeperList fsep tt_docs)
343
344 ppr_termM y p Term{dc=Right dc, subTerms=tt}
345 {- | dataConIsInfix dc, (t1:t2:tt') <- tt --TODO fixity
346 = parens (ppr_term1 True t1 <+> ppr dc <+> ppr_term1 True ppr t2)
347 <+> hsep (map (ppr_term1 True) tt)
348 -} -- TODO Printing infix constructors properly
349 | null tt = return$ ppr dc
350 | otherwise = do
351 tt_docs <- mapM (y app_prec) tt
352 return$ cparen (p >= app_prec) (ppr dc <+> pprDeeperList fsep tt_docs)
353
354 ppr_termM y p t@NewtypeWrap{} = pprNewtypeWrap y p t
355 ppr_termM y p RefWrap{wrapped_term=t} = do
356 contents <- y app_prec t
357 return$ cparen (p >= app_prec) (text "GHC.Prim.MutVar#" <+> contents)
358 -- The constructor name is wired in here ^^^ for the sake of simplicity.
359 -- I don't think mutvars are going to change in a near future.
360 -- In any case this is solely a presentation matter: MutVar# is
361 -- a datatype with no constructors, implemented by the RTS
362 -- (hence there is no way to obtain a datacon and print it).
363 ppr_termM _ _ t = ppr_termM1 t
364
365
366 ppr_termM1 :: Monad m => Term -> m SDoc
367 ppr_termM1 Prim{value=words, ty=ty} =
368 return$ text$ repPrim (tyConAppTyCon ty) words
369 ppr_termM1 Suspension{ty=ty, bound_to=Nothing} =
370 return (char '_' <+> ifPprDebug (text "::" <> ppr ty))
371 ppr_termM1 Suspension{ty=ty, bound_to=Just n}
372 -- | Just _ <- splitFunTy_maybe ty = return$ ptext (sLit("<function>")
373 | otherwise = return$ parens$ ppr n <> text "::" <> ppr ty
374 ppr_termM1 Term{} = panic "ppr_termM1 - Term"
375 ppr_termM1 RefWrap{} = panic "ppr_termM1 - RefWrap"
376 ppr_termM1 NewtypeWrap{} = panic "ppr_termM1 - NewtypeWrap"
377
378 pprNewtypeWrap y p NewtypeWrap{ty=ty, wrapped_term=t}
379 | Just (tc,_) <- tcSplitTyConApp_maybe ty
380 , ASSERT(isNewTyCon tc) True
381 , Just new_dc <- tyConSingleDataCon_maybe tc = do
382 real_term <- y max_prec t
383 return $ cparen (p >= app_prec) (ppr new_dc <+> real_term)
384 pprNewtypeWrap _ _ _ = panic "pprNewtypeWrap"
385
386 -------------------------------------------------------
387 -- Custom Term Pretty Printers
388 -------------------------------------------------------
389
390 -- We can want to customize the representation of a
391 -- term depending on its type.
392 -- However, note that custom printers have to work with
393 -- type representations, instead of directly with types.
394 -- We cannot use type classes here, unless we employ some
395 -- typerep trickery (e.g. Weirich's RepLib tricks),
396 -- which I didn't. Therefore, this code replicates a lot
397 -- of what type classes provide for free.
398
399 type CustomTermPrinter m = TermPrinterM m
400 -> [Precedence -> Term -> (m (Maybe SDoc))]
401
402 -- | Takes a list of custom printers with a explicit recursion knot and a term,
403 -- and returns the output of the first succesful printer, or the default printer
404 cPprTerm :: Monad m => CustomTermPrinter m -> Term -> m SDoc
405 cPprTerm printers_ = go 0 where
406 printers = printers_ go
407 go prec t = do
408 let default_ = Just `liftM` pprTermM go prec t
409 mb_customDocs = [pp prec t | pp <- printers] ++ [default_]
410 Just doc <- firstJustM mb_customDocs
411 return$ cparen (prec>app_prec+1) doc
412
413 firstJustM (mb:mbs) = mb >>= maybe (firstJustM mbs) (return . Just)
414 firstJustM [] = return Nothing
415
416 -- Default set of custom printers. Note that the recursion knot is explicit
417 cPprTermBase :: Monad m => CustomTermPrinter m
418 cPprTermBase y =
419 [ ifTerm (isTupleTy.ty) (\_p -> liftM (parens . hcat . punctuate comma)
420 . mapM (y (-1))
421 . subTerms)
422 , ifTerm (\t -> isTyCon listTyCon (ty t) && subTerms t `lengthIs` 2)
423 (\ p t -> doList p t)
424 , ifTerm (isTyCon intTyCon . ty) (coerceShow$ \(a::Int)->a)
425 , ifTerm (isTyCon charTyCon . ty) (coerceShow$ \(a::Char)->a)
426 , ifTerm (isTyCon floatTyCon . ty) (coerceShow$ \(a::Float)->a)
427 , ifTerm (isTyCon doubleTyCon . ty) (coerceShow$ \(a::Double)->a)
428 , ifTerm (isIntegerTy . ty) (coerceShow$ \(a::Integer)->a)
429 ]
430 where ifTerm pred f prec t@Term{}
431 | pred t = Just `liftM` f prec t
432 ifTerm _ _ _ _ = return Nothing
433
434 isTupleTy ty = fromMaybe False $ do
435 (tc,_) <- tcSplitTyConApp_maybe ty
436 return (isBoxedTupleTyCon tc)
437
438 isTyCon a_tc ty = fromMaybe False $ do
439 (tc,_) <- tcSplitTyConApp_maybe ty
440 return (a_tc == tc)
441
442 isIntegerTy ty = fromMaybe False $ do
443 (tc,_) <- tcSplitTyConApp_maybe ty
444 return (tyConName tc == integerTyConName)
445
446 coerceShow f _p = return . text . show . f . unsafeCoerce# . val
447
448 --Note pprinting of list terms is not lazy
449 doList p (Term{subTerms=[h,t]}) = do
450 let elems = h : getListTerms t
451 isConsLast = not(termType(last elems) `coreEqType` termType h)
452 print_elems <- mapM (y cons_prec) elems
453 return$ if isConsLast
454 then cparen (p >= cons_prec)
455 . pprDeeperList fsep
456 . punctuate (space<>colon)
457 $ print_elems
458 else brackets (pprDeeperList fcat$
459 punctuate comma print_elems)
460
461 where getListTerms Term{subTerms=[h,t]} = h : getListTerms t
462 getListTerms Term{subTerms=[]} = []
463 getListTerms t@Suspension{} = [t]
464 getListTerms t = pprPanic "getListTerms" (ppr t)
465 doList _ _ = panic "doList"
466
467
468 repPrim :: TyCon -> [Word] -> String
469 repPrim t = rep where
470 rep x
471 | t == charPrimTyCon = show (build x :: Char)
472 | t == intPrimTyCon = show (build x :: Int)
473 | t == wordPrimTyCon = show (build x :: Word)
474 | t == floatPrimTyCon = show (build x :: Float)
475 | t == doublePrimTyCon = show (build x :: Double)
476 | t == int32PrimTyCon = show (build x :: Int32)
477 | t == word32PrimTyCon = show (build x :: Word32)
478 | t == int64PrimTyCon = show (build x :: Int64)
479 | t == word64PrimTyCon = show (build x :: Word64)
480 | t == addrPrimTyCon = show (nullPtr `plusPtr` build x)
481 | t == stablePtrPrimTyCon = "<stablePtr>"
482 | t == stableNamePrimTyCon = "<stableName>"
483 | t == statePrimTyCon = "<statethread>"
484 | t == realWorldTyCon = "<realworld>"
485 | t == threadIdPrimTyCon = "<ThreadId>"
486 | t == weakPrimTyCon = "<Weak>"
487 | t == arrayPrimTyCon = "<array>"
488 | t == byteArrayPrimTyCon = "<bytearray>"
489 | t == mutableArrayPrimTyCon = "<mutableArray>"
490 | t == mutableByteArrayPrimTyCon = "<mutableByteArray>"
491 | t == mutVarPrimTyCon= "<mutVar>"
492 | t == mVarPrimTyCon = "<mVar>"
493 | t == tVarPrimTyCon = "<tVar>"
494 | otherwise = showSDoc (char '<' <> ppr t <> char '>')
495 where build ww = unsafePerformIO $ withArray ww (peek . castPtr)
496 -- This ^^^ relies on the representation of Haskell heap values being
497 -- the same as in a C array.
498
499 -----------------------------------
500 -- Type Reconstruction
501 -----------------------------------
502 {-
503 Type Reconstruction is type inference done on heap closures.
504 The algorithm walks the heap generating a set of equations, which
505 are solved with syntactic unification.
506 A type reconstruction equation looks like:
507
508 <datacon reptype> = <actual heap contents>
509
510 The full equation set is generated by traversing all the subterms, starting
511 from a given term.
512
513 The only difficult part is that newtypes are only found in the lhs of equations.
514 Right hand sides are missing them. We can either (a) drop them from the lhs, or
515 (b) reconstruct them in the rhs when possible.
516
517 The function congruenceNewtypes takes a shot at (b)
518 -}
519
520
521 -- A (non-mutable) tau type containing
522 -- existentially quantified tyvars.
523 -- (since GHC type language currently does not support
524 -- existentials, we leave these variables unquantified)
525 type RttiType = Type
526
527 -- An incomplete type as stored in GHCi:
528 -- no polymorphism: no quantifiers & all tyvars are skolem.
529 type GhciType = Type
530
531
532 -- The Type Reconstruction monad
533 --------------------------------
534 type TR a = TcM a
535
536 runTR :: HscEnv -> TR a -> IO a
537 runTR hsc_env thing = do
538 mb_val <- runTR_maybe hsc_env thing
539 case mb_val of
540 Nothing -> error "unable to :print the term"
541 Just x -> return x
542
543 runTR_maybe :: HscEnv -> TR a -> IO (Maybe a)
544 runTR_maybe hsc_env = fmap snd . initTc hsc_env HsSrcFile False iNTERACTIVE
545
546 traceTR :: SDoc -> TR ()
547 traceTR = liftTcM . traceOptTcRn Opt_D_dump_rtti
548
549
550 -- Semantically different to recoverM in TcRnMonad
551 -- recoverM retains the errors in the first action,
552 -- whereas recoverTc here does not
553 recoverTR :: TR a -> TR a -> TR a
554 recoverTR recover thing = do
555 (_,mb_res) <- tryTcErrs thing
556 case mb_res of
557 Nothing -> recover
558 Just res -> return res
559
560 trIO :: IO a -> TR a
561 trIO = liftTcM . liftIO
562
563 liftTcM :: TcM a -> TR a
564 liftTcM = id
565
566 newVar :: Kind -> TR TcType
567 newVar = liftTcM . newFlexiTyVarTy
568
569 type RttiInstantiation = [(TcTyVar, TyVar)]
570 -- Associates the typechecker-world meta type variables
571 -- (which are mutable and may be refined), to their
572 -- debugger-world RuntimeUnkSkol counterparts.
573 -- If the TcTyVar has not been refined by the runtime type
574 -- elaboration, then we want to turn it back into the
575 -- original RuntimeUnkSkol
576
577 -- | Returns the instantiated type scheme ty', and the
578 -- mapping from new (instantiated) -to- old (skolem) type variables
579 -- We want this mapping just for old RuntimeUnkSkols, to avoid
580 -- gratuitously changing their unique on every trip
581 instScheme :: QuantifiedType -> TR (TcType, RttiInstantiation)
582 instScheme (tvs, ty)
583 = liftTcM $ do { (tvs', _, subst) <- tcInstTyVars tvs
584 ; let rtti_inst = [(tv',tv) | (tv',tv) <- tvs' `zip` tvs
585 , isRuntimeUnkSkol tv]
586 ; return (substTy subst ty, rtti_inst) }
587
588 applyRevSubst :: RttiInstantiation -> TR ()
589 -- Apply the *reverse* substitution in-place to any un-filled-in
590 -- meta tyvars. This recovers the original debugger-world variable
591 -- unless it has been refined by new information from the heap
592 applyRevSubst pairs = liftTcM (mapM_ do_pair pairs)
593 where
594 do_pair (tc_tv, rtti_tv)
595 = do { tc_ty <- zonkTcTyVar tc_tv
596 ; case tcGetTyVar_maybe tc_ty of
597 Just tv | isMetaTyVar tv -> writeMetaTyVar tv (mkTyVarTy rtti_tv)
598 _ -> return () }
599
600 -- Adds a constraint of the form t1 == t2
601 -- t1 is expected to come from walking the heap
602 -- t2 is expected to come from a datacon signature
603 -- Before unification, congruenceNewtypes needs to
604 -- do its magic.
605 addConstraint :: TcType -> TcType -> TR ()
606 addConstraint actual expected = do
607 traceTR (text "add constraint:" <+> fsep [ppr actual, equals, ppr expected])
608 recoverTR (traceTR $ fsep [text "Failed to unify", ppr actual,
609 text "with", ppr expected]) $
610 do { (ty1, ty2) <- congruenceNewtypes actual expected
611 ; _ <- captureConstraints $ unifyType ty1 ty2
612 ; return () }
613 -- TOMDO: what about the coercion?
614 -- we should consider family instances
615
616
617 -- Type & Term reconstruction
618 ------------------------------
619 cvObtainTerm :: HscEnv -> Int -> Bool -> RttiType -> HValue -> IO Term
620 cvObtainTerm hsc_env max_depth force old_ty hval = runTR hsc_env $ do
621 -- we quantify existential tyvars as universal,
622 -- as this is needed to be able to manipulate
623 -- them properly
624 let quant_old_ty@(old_tvs, old_tau) = quantifyType old_ty
625 sigma_old_ty = mkForAllTys old_tvs old_tau
626 traceTR (text "Term reconstruction started with initial type " <> ppr old_ty)
627 term <-
628 if null old_tvs
629 then do
630 term <- go max_depth sigma_old_ty sigma_old_ty hval
631 term' <- zonkTerm term
632 return $ fixFunDictionaries $ expandNewtypes term'
633 else do
634 (old_ty', rev_subst) <- instScheme quant_old_ty
635 my_ty <- newVar argTypeKind
636 when (check1 quant_old_ty) (traceTR (text "check1 passed") >>
637 addConstraint my_ty old_ty')
638 term <- go max_depth my_ty sigma_old_ty hval
639 new_ty <- zonkTcType (termType term)
640 if isMonomorphic new_ty || check2 (quantifyType new_ty) quant_old_ty
641 then do
642 traceTR (text "check2 passed")
643 addConstraint new_ty old_ty'
644 applyRevSubst rev_subst
645 zterm' <- zonkTerm term
646 return ((fixFunDictionaries . expandNewtypes) zterm')
647 else do
648 traceTR (text "check2 failed" <+> parens
649 (ppr term <+> text "::" <+> ppr new_ty))
650 -- we have unsound types. Replace constructor types in
651 -- subterms with tyvars
652 zterm' <- mapTermTypeM
653 (\ty -> case tcSplitTyConApp_maybe ty of
654 Just (tc, _:_) | tc /= funTyCon
655 -> newVar argTypeKind
656 _ -> return ty)
657 term
658 zonkTerm zterm'
659 traceTR (text "Term reconstruction completed." $$
660 text "Term obtained: " <> ppr term $$
661 text "Type obtained: " <> ppr (termType term))
662 return term
663 where
664 go :: Int -> Type -> Type -> HValue -> TcM Term
665 go max_depth _ _ _ | seq max_depth False = undefined
666 go 0 my_ty _old_ty a = do
667 traceTR (text "Gave up reconstructing a term after" <>
668 int max_depth <> text " steps")
669 clos <- trIO $ getClosureData a
670 return (Suspension (tipe clos) my_ty a Nothing)
671 go max_depth my_ty old_ty a = do
672 let monomorphic = not(isTyVarTy my_ty)
673 -- This ^^^ is a convention. The ancestor tests for
674 -- monomorphism and passes a type instead of a tv
675 clos <- trIO $ getClosureData a
676 case tipe clos of
677 -- Thunks we may want to force
678 t | isThunk t && force -> traceTR (text "Forcing a " <> text (show t)) >>
679 seq a (go (pred max_depth) my_ty old_ty a)
680 -- Blackholes are indirections iff the payload is not TSO or BLOCKING_QUEUE. So we
681 -- treat them like indirections; if the payload is TSO or BLOCKING_QUEUE, we'll end up
682 -- showing '_' which is what we want.
683 Blackhole -> do traceTR (text "Following a BLACKHOLE")
684 appArr (go max_depth my_ty old_ty) (ptrs clos) 0
685 -- We always follow indirections
686 Indirection i -> do traceTR (text "Following an indirection" <> parens (int i) )
687 go max_depth my_ty old_ty $! (ptrs clos ! 0)
688 -- We also follow references
689 MutVar _ | Just (tycon,[world,contents_ty]) <- tcSplitTyConApp_maybe old_ty
690 -> do
691 -- Deal with the MutVar# primitive
692 -- It does not have a constructor at all,
693 -- so we simulate the following one
694 -- MutVar# :: contents_ty -> MutVar# s contents_ty
695 traceTR (text "Following a MutVar")
696 contents_tv <- newVar liftedTypeKind
697 contents <- trIO$ IO$ \w -> readMutVar# (unsafeCoerce# a) w
698 ASSERT(isUnliftedTypeKind $ typeKind my_ty) return ()
699 (mutvar_ty,_) <- instScheme $ quantifyType $ mkFunTy
700 contents_ty (mkTyConApp tycon [world,contents_ty])
701 addConstraint (mkFunTy contents_tv my_ty) mutvar_ty
702 x <- go (pred max_depth) contents_tv contents_ty contents
703 return (RefWrap my_ty x)
704
705 -- The interesting case
706 Constr -> do
707 traceTR (text "entering a constructor " <>
708 if monomorphic
709 then parens (text "already monomorphic: " <> ppr my_ty)
710 else Outputable.empty)
711 Right dcname <- dataConInfoPtrToName (infoPtr clos)
712 (_,mb_dc) <- tryTcErrs (tcLookupDataCon dcname)
713 case mb_dc of
714 Nothing -> do -- This can happen for private constructors compiled -O0
715 -- where the .hi descriptor does not export them
716 -- In such case, we return a best approximation:
717 -- ignore the unpointed args, and recover the pointeds
718 -- This preserves laziness, and should be safe.
719 let tag = showSDoc (ppr dcname)
720 vars <- replicateM (length$ elems$ ptrs clos)
721 (newVar (liftedTypeKind))
722 subTerms <- sequence [appArr (go (pred max_depth) tv tv) (ptrs clos) i
723 | (i, tv) <- zip [0..] vars]
724 return (Term my_ty (Left ('<' : tag ++ ">")) a subTerms)
725 Just dc -> do
726 let subTtypes = matchSubTypes dc old_ty
727 subTermTvs <- mapMif (not . isMonomorphic)
728 (\t -> newVar (typeKind t))
729 subTtypes
730 let (subTermsP, subTermsNP) = partition (\(ty,_) -> isLifted ty
731 || isRefType ty)
732 (zip subTtypes subTermTvs)
733 (subTtypesP, subTermTvsP ) = unzip subTermsP
734 (subTtypesNP, _subTermTvsNP) = unzip subTermsNP
735
736 -- When we already have all the information, avoid solving
737 -- unnecessary constraints. Propagation of type information
738 -- to subterms is already being done via matching.
739 when (not monomorphic) $ do
740 let myType = mkFunTys subTermTvs my_ty
741 (signatureType,_) <- instScheme (mydataConType dc)
742 -- It is vital for newtype reconstruction that the unification step
743 -- is done right here, _before_ the subterms are RTTI reconstructed
744 addConstraint myType signatureType
745 subTermsP <- sequence
746 [ appArr (go (pred max_depth) tv t) (ptrs clos) i
747 | (i,tv,t) <- zip3 [0..] subTermTvsP subTtypesP]
748 let unboxeds = extractUnboxed subTtypesNP clos
749 subTermsNP = map (uncurry Prim) (zip subTtypesNP unboxeds)
750 subTerms = reOrderTerms subTermsP subTermsNP subTtypes
751 return (Term my_ty (Right dc) a subTerms)
752 -- The otherwise case: can be a Thunk,AP,PAP,etc.
753 tipe_clos ->
754 return (Suspension tipe_clos my_ty a Nothing)
755
756 matchSubTypes dc ty
757 | ty' <- repType ty -- look through newtypes
758 , Just (tc,ty_args) <- tcSplitTyConApp_maybe ty'
759 , dc `elem` tyConDataCons tc
760 -- It is necessary to check that dc is actually a constructor for tycon tc,
761 -- because it may be the case that tc is a recursive newtype and tcSplitTyConApp
762 -- has not removed it. In that case, we happily give up and don't match
763 = myDataConInstArgTys dc ty_args
764 | otherwise = dataConRepArgTys dc
765
766 -- put together pointed and nonpointed subterms in the
767 -- correct order.
768 reOrderTerms _ _ [] = []
769 reOrderTerms pointed unpointed (ty:tys)
770 | isLifted ty || isRefType ty
771 = ASSERT2(not(null pointed)
772 , ptext (sLit "reOrderTerms") $$
773 (ppr pointed $$ ppr unpointed))
774 let (t:tt) = pointed in t : reOrderTerms tt unpointed tys
775 | otherwise = ASSERT2(not(null unpointed)
776 , ptext (sLit "reOrderTerms") $$
777 (ppr pointed $$ ppr unpointed))
778 let (t:tt) = unpointed in t : reOrderTerms pointed tt tys
779
780 -- insert NewtypeWraps around newtypes
781 expandNewtypes = foldTerm idTermFold { fTerm = worker } where
782 worker ty dc hval tt
783 | Just (tc, args) <- tcSplitTyConApp_maybe ty
784 , isNewTyCon tc
785 , wrapped_type <- newTyConInstRhs tc args
786 , Just dc' <- tyConSingleDataCon_maybe tc
787 , t' <- worker wrapped_type dc hval tt
788 = NewtypeWrap ty (Right dc') t'
789 | otherwise = Term ty dc hval tt
790
791
792 -- Avoid returning types where predicates have been expanded to dictionaries.
793 fixFunDictionaries = foldTerm idTermFold {fSuspension = worker} where
794 worker ct ty hval n | isFunTy ty = Suspension ct (dictsView ty) hval n
795 | otherwise = Suspension ct ty hval n
796
797
798 -- Fast, breadth-first Type reconstruction
799 ------------------------------------------
800 cvReconstructType :: HscEnv -> Int -> GhciType -> HValue -> IO (Maybe Type)
801 cvReconstructType hsc_env max_depth old_ty hval = runTR_maybe hsc_env $ do
802 traceTR (text "RTTI started with initial type " <> ppr old_ty)
803 let sigma_old_ty@(old_tvs, _) = quantifyType old_ty
804 new_ty <-
805 if null old_tvs
806 then return old_ty
807 else do
808 (old_ty', rev_subst) <- instScheme sigma_old_ty
809 my_ty <- newVar argTypeKind
810 when (check1 sigma_old_ty) (traceTR (text "check1 passed") >>
811 addConstraint my_ty old_ty')
812 search (isMonomorphic `fmap` zonkTcType my_ty)
813 (\(ty,a) -> go ty a)
814 (Seq.singleton (my_ty, hval))
815 max_depth
816 new_ty <- zonkTcType my_ty
817 if isMonomorphic new_ty || check2 (quantifyType new_ty) sigma_old_ty
818 then do
819 traceTR (text "check2 passed" <+> ppr old_ty $$ ppr new_ty)
820 addConstraint my_ty old_ty'
821 applyRevSubst rev_subst
822 zonkRttiType new_ty
823 else traceTR (text "check2 failed" <+> parens (ppr new_ty)) >>
824 return old_ty
825 traceTR (text "RTTI completed. Type obtained:" <+> ppr new_ty)
826 return new_ty
827 where
828 -- search :: m Bool -> ([a] -> [a] -> [a]) -> [a] -> m ()
829 search _ _ _ 0 = traceTR (text "Failed to reconstruct a type after " <>
830 int max_depth <> text " steps")
831 search stop expand l d =
832 case viewl l of
833 EmptyL -> return ()
834 x :< xx -> unlessM stop $ do
835 new <- expand x
836 search stop expand (xx `mappend` Seq.fromList new) $! (pred d)
837
838 -- returns unification tasks,since we are going to want a breadth-first search
839 go :: Type -> HValue -> TR [(Type, HValue)]
840 go my_ty a = do
841 clos <- trIO $ getClosureData a
842 case tipe clos of
843 Blackhole -> appArr (go my_ty) (ptrs clos) 0 -- carefully, don't eval the TSO
844 Indirection _ -> go my_ty $! (ptrs clos ! 0)
845 MutVar _ -> do
846 contents <- trIO$ IO$ \w -> readMutVar# (unsafeCoerce# a) w
847 tv' <- newVar liftedTypeKind
848 world <- newVar liftedTypeKind
849 addConstraint my_ty (mkTyConApp mutVarPrimTyCon [world,tv'])
850 return [(tv', contents)]
851 Constr -> do
852 Right dcname <- dataConInfoPtrToName (infoPtr clos)
853 (_,mb_dc) <- tryTcErrs (tcLookupDataCon dcname)
854 case mb_dc of
855 Nothing-> do
856 -- TODO: Check this case
857 forM [0..length (elems $ ptrs clos)] $ \i -> do
858 tv <- newVar liftedTypeKind
859 return$ appArr (\e->(tv,e)) (ptrs clos) i
860
861 Just dc -> do
862 subTtypes <- mapMif (not . isMonomorphic)
863 (\t -> newVar (typeKind t))
864 (dataConRepArgTys dc)
865
866 -- It is vital for newtype reconstruction that the unification step
867 -- is done right here, _before_ the subterms are RTTI reconstructed
868 let myType = mkFunTys subTtypes my_ty
869 (signatureType,_) <- instScheme (mydataConType dc)
870 addConstraint myType signatureType
871 return $ [ appArr (\e->(t,e)) (ptrs clos) i
872 | (i,t) <- zip [0..] (filter (isLifted |.| isRefType) subTtypes)]
873 _ -> return []
874
875 -- Compute the difference between a base type and the type found by RTTI
876 -- improveType <base_type> <rtti_type>
877 -- The types can contain skolem type variables, which need to be treated as normal vars.
878 -- In particular, we want them to unify with things.
879 improveRTTIType :: HscEnv -> RttiType -> RttiType -> Maybe TvSubst
880 improveRTTIType _ base_ty new_ty
881 = U.tcUnifyTys (const U.BindMe) [base_ty] [new_ty]
882
883 myDataConInstArgTys :: DataCon -> [Type] -> [Type]
884 myDataConInstArgTys dc args
885 | null (dataConExTyVars dc) && null (dataConEqTheta dc) = dataConInstArgTys dc args
886 | otherwise = dataConRepArgTys dc
887
888 mydataConType :: DataCon -> QuantifiedType
889 -- ^ Custom version of DataCon.dataConUserType where we
890 -- - remove the equality constraints
891 -- - use the representation types for arguments, including dictionaries
892 -- - keep the original result type
893 mydataConType dc
894 = ( (univ_tvs `minusList` map fst eq_spec) ++ ex_tvs
895 , mkFunTys arg_tys res_ty )
896 where univ_tvs = dataConUnivTyVars dc
897 ex_tvs = dataConExTyVars dc
898 eq_spec = dataConEqSpec dc
899 arg_tys = [case a of
900 PredTy p -> predTypeRep p
901 _ -> a
902 | a <- dataConRepArgTys dc]
903 res_ty = dataConOrigResTy dc
904
905 isRefType :: Type -> Bool
906 isRefType ty
907 | Just (tc, _) <- tcSplitTyConApp_maybe ty' = isRefTyCon tc
908 | otherwise = False
909 where ty'= repType ty
910
911 isRefTyCon :: TyCon -> Bool
912 isRefTyCon tc = tc `elem` [mutVarPrimTyCon, mVarPrimTyCon, tVarPrimTyCon]
913
914 -- Soundness checks
915 --------------------
916 {-
917 This is not formalized anywhere, so hold to your seats!
918 RTTI in the presence of newtypes can be a tricky and unsound business.
919
920 Example:
921 ~~~~~~~~~
922 Suppose we are doing RTTI for a partially evaluated
923 closure t, the real type of which is t :: MkT Int, for
924
925 newtype MkT a = MkT [Maybe a]
926
927 The table below shows the results of RTTI and the improvement
928 calculated for different combinations of evaluatedness and :type t.
929 Regard the two first columns as input and the next two as output.
930
931 # | t | :type t | rtti(t) | improv. | result
932 ------------------------------------------------------------
933 1 | _ | t b | a | none | OK
934 2 | _ | MkT b | a | none | OK
935 3 | _ | t Int | a | none | OK
936
937 If t is not evaluated at *all*, we are safe.
938
939 4 | (_ : _) | t b | [a] | t = [] | UNSOUND
940 5 | (_ : _) | MkT b | MkT a | none | OK (compensating for the missing newtype)
941 6 | (_ : _) | t Int | [Int] | t = [] | UNSOUND
942
943 If a is a minimal whnf, we run into trouble. Note that
944 row 5 above does newtype enrichment on the ty_rtty parameter.
945
946 7 | (Just _:_)| t b |[Maybe a] | t = [], | UNSOUND
947 | | | b = Maybe a|
948
949 8 | (Just _:_)| MkT b | MkT a | none | OK
950 9 | (Just _:_)| t Int | FAIL | none | OK
951
952 And if t is any more evaluated than whnf, we are still in trouble.
953 Because constraints are solved in top-down order, when we reach the
954 Maybe subterm what we got is already unsound. This explains why the
955 row 9 fails to complete.
956
957 10 | (Just _:_)| t Int | [Maybe a] | FAIL | OK
958 11 | (Just 1:_)| t Int | [Maybe Int] | FAIL | OK
959
960 We can undo the failure in row 9 by leaving out the constraint
961 coming from the type signature of t (i.e., the 2nd column).
962 Note that this type information is still used
963 to calculate the improvement. But we fail
964 when trying to calculate the improvement, as there is no unifier for
965 t Int = [Maybe a] or t Int = [Maybe Int].
966
967
968 Another set of examples with t :: [MkT (Maybe Int)] \equiv [[Maybe (Maybe Int)]]
969
970 # | t | :type t | rtti(t) | improvement | result
971 ---------------------------------------------------------------------
972 1 |(Just _:_) | [t (Maybe a)] | [[Maybe b]] | t = [] |
973 | | | | b = Maybe a |
974
975 The checks:
976 ~~~~~~~~~~~
977 Consider a function obtainType that takes a value and a type and produces
978 the Term representation and a substitution (the improvement).
979 Assume an auxiliar rtti' function which does the actual job if recovering
980 the type, but which may produce a false type.
981
982 In pseudocode:
983
984 rtti' :: a -> IO Type -- Does not use the static type information
985
986 obtainType :: a -> Type -> IO (Maybe (Term, Improvement))
987 obtainType v old_ty = do
988 rtti_ty <- rtti' v
989 if monomorphic rtti_ty || (check rtti_ty old_ty)
990 then ...
991 else return Nothing
992 where check rtti_ty old_ty = check1 rtti_ty &&
993 check2 rtti_ty old_ty
994
995 check1 :: Type -> Bool
996 check2 :: Type -> Type -> Bool
997
998 Now, if rtti' returns a monomorphic type, we are safe.
999 If that is not the case, then we consider two conditions.
1000
1001
1002 1. To prevent the class of unsoundness displayed by
1003 rows 4 and 7 in the example: no higher kind tyvars
1004 accepted.
1005
1006 check1 (t a) = NO
1007 check1 (t Int) = NO
1008 check1 ([] a) = YES
1009
1010 2. To prevent the class of unsoundness shown by row 6,
1011 the rtti type should be structurally more
1012 defined than the old type we are comparing it to.
1013 check2 :: NewType -> OldType -> Bool
1014 check2 a _ = True
1015 check2 [a] a = True
1016 check2 [a] (t Int) = False
1017 check2 [a] (t a) = False -- By check1 we never reach this equation
1018 check2 [Int] a = True
1019 check2 [Int] (t Int) = True
1020 check2 [Maybe a] (t Int) = False
1021 check2 [Maybe Int] (t Int) = True
1022 check2 (Maybe [a]) (m [Int]) = False
1023 check2 (Maybe [Int]) (m [Int]) = True
1024
1025 -}
1026
1027 check1 :: QuantifiedType -> Bool
1028 check1 (tvs, _) = not $ any isHigherKind (map tyVarKind tvs)
1029 where
1030 isHigherKind = not . null . fst . splitKindFunTys
1031
1032 check2 :: QuantifiedType -> QuantifiedType -> Bool
1033 check2 (_, rtti_ty) (_, old_ty)
1034 | Just (_, rttis) <- tcSplitTyConApp_maybe rtti_ty
1035 = case () of
1036 _ | Just (_,olds) <- tcSplitTyConApp_maybe old_ty
1037 -> and$ zipWith check2 (map quantifyType rttis) (map quantifyType olds)
1038 _ | Just _ <- splitAppTy_maybe old_ty
1039 -> isMonomorphicOnNonPhantomArgs rtti_ty
1040 _ -> True
1041 | otherwise = True
1042
1043 -- Dealing with newtypes
1044 --------------------------
1045 {-
1046 congruenceNewtypes does a parallel fold over two Type values,
1047 compensating for missing newtypes on both sides.
1048 This is necessary because newtypes are not present
1049 in runtime, but sometimes there is evidence available.
1050 Evidence can come from DataCon signatures or
1051 from compile-time type inference.
1052 What we are doing here is an approximation
1053 of unification modulo a set of equations derived
1054 from newtype definitions. These equations should be the
1055 same as the equality coercions generated for newtypes
1056 in System Fc. The idea is to perform a sort of rewriting,
1057 taking those equations as rules, before launching unification.
1058
1059 The caller must ensure the following.
1060 The 1st type (lhs) comes from the heap structure of ptrs,nptrs.
1061 The 2nd type (rhs) comes from a DataCon type signature.
1062 Rewriting (i.e. adding/removing a newtype wrapper) can happen
1063 in both types, but in the rhs it is restricted to the result type.
1064
1065 Note that it is very tricky to make this 'rewriting'
1066 work with the unification implemented by TcM, where
1067 substitutions are operationally inlined. The order in which
1068 constraints are unified is vital as we cannot modify
1069 anything that has been touched by a previous unification step.
1070 Therefore, congruenceNewtypes is sound only if the types
1071 recovered by the RTTI mechanism are unified Top-Down.
1072 -}
1073 congruenceNewtypes :: TcType -> TcType -> TR (TcType,TcType)
1074 congruenceNewtypes lhs rhs = go lhs rhs >>= \rhs' -> return (lhs,rhs')
1075 where
1076 go l r
1077 -- TyVar lhs inductive case
1078 | Just tv <- getTyVar_maybe l
1079 , isTcTyVar tv
1080 , isMetaTyVar tv
1081 = recoverTR (return r) $ do
1082 Indirect ty_v <- readMetaTyVar tv
1083 traceTR $ fsep [text "(congruence) Following indirect tyvar:",
1084 ppr tv, equals, ppr ty_v]
1085 go ty_v r
1086 -- FunTy inductive case
1087 | Just (l1,l2) <- splitFunTy_maybe l
1088 , Just (r1,r2) <- splitFunTy_maybe r
1089 = do r2' <- go l2 r2
1090 r1' <- go l1 r1
1091 return (mkFunTy r1' r2')
1092 -- TyconApp Inductive case; this is the interesting bit.
1093 | Just (tycon_l, _) <- tcSplitTyConApp_maybe lhs
1094 , Just (tycon_r, _) <- tcSplitTyConApp_maybe rhs
1095 , tycon_l /= tycon_r
1096 = upgrade tycon_l r
1097
1098 | otherwise = return r
1099
1100 where upgrade :: TyCon -> Type -> TR Type
1101 upgrade new_tycon ty
1102 | not (isNewTyCon new_tycon) = do
1103 traceTR (text "(Upgrade) Not matching newtype evidence: " <>
1104 ppr new_tycon <> text " for " <> ppr ty)
1105 return ty
1106 | otherwise = do
1107 traceTR (text "(Upgrade) upgraded " <> ppr ty <>
1108 text " in presence of newtype evidence " <> ppr new_tycon)
1109 vars <- mapM (newVar . tyVarKind) (tyConTyVars new_tycon)
1110 let ty' = mkTyConApp new_tycon vars
1111 _ <- liftTcM (unifyType ty (repType ty'))
1112 -- assumes that reptype doesn't ^^^^ touch tyconApp args
1113 return ty'
1114
1115
1116 zonkTerm :: Term -> TcM Term
1117 zonkTerm = foldTermM (TermFoldM
1118 { fTermM = \ty dc v tt -> zonkRttiType ty >>= \ty' ->
1119 return (Term ty' dc v tt)
1120 , fSuspensionM = \ct ty v b -> zonkRttiType ty >>= \ty ->
1121 return (Suspension ct ty v b)
1122 , fNewtypeWrapM = \ty dc t -> zonkRttiType ty >>= \ty' ->
1123 return$ NewtypeWrap ty' dc t
1124 , fRefWrapM = \ty t -> return RefWrap `ap`
1125 zonkRttiType ty `ap` return t
1126 , fPrimM = (return.) . Prim })
1127
1128 zonkRttiType :: TcType -> TcM Type
1129 -- Zonk the type, replacing any unbound Meta tyvars
1130 -- by skolems, safely out of Meta-tyvar-land
1131 zonkRttiType = zonkType (mkZonkTcTyVar zonk_unbound_meta)
1132 where
1133 zonk_unbound_meta tv
1134 = ASSERT( isTcTyVar tv )
1135 do { tv' <- skolemiseUnboundMetaTyVar RuntimeUnkSkol tv
1136 -- This is where RuntimeUnkSkols are born:
1137 -- otherwise-unconstrained unification variables are
1138 -- turned into RuntimeUnkSkols as they leave the
1139 -- typechecker's monad
1140 ; return (mkTyVarTy tv') }
1141
1142 --------------------------------------------------------------------------------
1143 -- Restore Class predicates out of a representation type
1144 dictsView :: Type -> Type
1145 -- dictsView ty = ty
1146 dictsView (FunTy (TyConApp tc_dict args) ty)
1147 | Just c <- tyConClass_maybe tc_dict
1148 = FunTy (PredTy (ClassP c args)) (dictsView ty)
1149 dictsView ty
1150 | Just (tc_fun, [TyConApp tc_dict args, ty2]) <- tcSplitTyConApp_maybe ty
1151 , Just c <- tyConClass_maybe tc_dict
1152 = mkTyConApp tc_fun [PredTy (ClassP c args), dictsView ty2]
1153 dictsView ty = ty
1154
1155
1156 -- Use only for RTTI types
1157 isMonomorphic :: RttiType -> Bool
1158 isMonomorphic ty = noExistentials && noUniversals
1159 where (tvs, _, ty') = tcSplitSigmaTy ty
1160 noExistentials = isEmptyVarSet (tyVarsOfType ty')
1161 noUniversals = null tvs
1162
1163 -- Use only for RTTI types
1164 isMonomorphicOnNonPhantomArgs :: RttiType -> Bool
1165 isMonomorphicOnNonPhantomArgs ty
1166 | Just (tc, all_args) <- tcSplitTyConApp_maybe (repType ty)
1167 , phantom_vars <- tyConPhantomTyVars tc
1168 , concrete_args <- [ arg | (tyv,arg) <- tyConTyVars tc `zip` all_args
1169 , tyv `notElem` phantom_vars]
1170 = all isMonomorphicOnNonPhantomArgs concrete_args
1171 | Just (ty1, ty2) <- splitFunTy_maybe ty
1172 = all isMonomorphicOnNonPhantomArgs [ty1,ty2]
1173 | otherwise = isMonomorphic ty
1174
1175 tyConPhantomTyVars :: TyCon -> [TyVar]
1176 tyConPhantomTyVars tc
1177 | isAlgTyCon tc
1178 , Just dcs <- tyConDataCons_maybe tc
1179 , dc_vars <- concatMap dataConUnivTyVars dcs
1180 = tyConTyVars tc \\ dc_vars
1181 tyConPhantomTyVars _ = []
1182
1183 type QuantifiedType = ([TyVar], Type) -- Make the free type variables explicit
1184
1185 quantifyType :: Type -> QuantifiedType
1186 -- Generalize the type: find all free tyvars and wrap in the appropiate ForAll.
1187 quantifyType ty = (varSetElems (tyVarsOfType ty), ty)
1188
1189 mapMif :: Monad m => (a -> Bool) -> (a -> m a) -> [a] -> m [a]
1190 mapMif pred f xx = sequence $ mapMif_ pred f xx
1191 where
1192 mapMif_ _ _ [] = []
1193 mapMif_ pred f (x:xx) = (if pred x then f x else return x) : mapMif_ pred f xx
1194
1195 unlessM :: Monad m => m Bool -> m () -> m ()
1196 unlessM condM acc = condM >>= \c -> unless c acc
1197
1198
1199 -- Strict application of f at index i
1200 appArr :: Ix i => (e -> a) -> Array i e -> Int -> a
1201 appArr f a@(Array _ _ _ ptrs#) i@(I# i#)
1202 = ASSERT2 (i < length(elems a), ppr(length$ elems a, i))
1203 case indexArray# ptrs# i# of
1204 (# e #) -> f e
1205
1206 amap' :: (t -> b) -> Array Int t -> [b]
1207 amap' f (Array i0 i _ arr#) = map g [0 .. i - i0]
1208 where g (I# i#) = case indexArray# arr# i# of
1209 (# e #) -> f e
1210
1211
1212 isLifted :: Type -> Bool
1213 isLifted = not . isUnLiftedType
1214
1215 extractUnboxed :: [Type] -> Closure -> [[Word]]
1216 extractUnboxed tt clos = go tt (nonPtrs clos)
1217 where sizeofType t
1218 | Just (tycon,_) <- tcSplitTyConApp_maybe t
1219 = ASSERT (isPrimTyCon tycon) sizeofTyCon tycon
1220 | otherwise = pprPanic "Expected a TcTyCon" (ppr t)
1221 go [] _ = []
1222 go (t:tt) xx
1223 | (x, rest) <- splitAt (sizeofType t) xx
1224 = x : go tt rest
1225
1226 sizeofTyCon :: TyCon -> Int -- in *words*
1227 sizeofTyCon = primRepSizeW . tyConPrimRep
1228
1229
1230 (|.|) :: (a -> Bool) -> (a -> Bool) -> a -> Bool
1231 (f |.| g) x = f x || g x