\begin{code}
module NewDemand(
- Demand(..), Keepity(..), Deferredness(..),
- topDmd, lazyDmd, seqDmd, evalDmd, isStrictDmd,
+ Demand(..), Keepity(..),
+ mkSeq, topDmd, lazyDmd, seqDmd, evalDmd, isStrictDmd, defer,
- DmdType(..), topDmdType, mkDmdType, mkTopDmdType,
+ DmdType(..), topDmdType, botDmdType, mkDmdType, mkTopDmdType,
dmdTypeDepth, dmdTypeRes,
DmdEnv, emptyDmdEnv,
DmdResult(..), isBotRes, returnsCPR,
- StrictSig(..), mkStrictSig, topSig, botSig,
+ StrictSig(..), mkStrictSig, topSig, botSig, isTopSig,
splitStrictSig, strictSigResInfo,
pprIfaceStrictSig, appIsBottom, isBottomingSig
) where
#include "HsVersions.h"
import BasicTypes ( Arity )
-import Var ( Id )
-import VarEnv ( VarEnv, emptyVarEnv )
+import VarEnv ( VarEnv, emptyVarEnv, isEmptyVarEnv )
import UniqFM ( ufmToList )
-import qualified Demand
import Outputable
\end{code}
ppr (DmdType fv ds res)
= hsep [text "DmdType",
hcat (map ppr ds) <> ppr res,
- braces (fsep (map pp_elt (ufmToList fv)))]
+ if null fv_elts then empty
+ else braces (fsep (map pp_elt fv_elts))]
where
pp_elt (uniq, dmd) = ppr uniq <> text "->" <> ppr dmd
+ fv_elts = ufmToList fv
instance Outputable DmdResult where
- ppr TopRes = empty
- ppr RetCPR = char 'M'
- ppr BotRes = char 'X'
+ ppr TopRes = empty -- Keep these distinct from Demand letters
+ ppr RetCPR = char 'm' -- so that we can print strictness sigs as
+ ppr BotRes = char 'b' -- dddr
+ -- without ambiguity
emptyDmdEnv = emptyVarEnv
topDmdType = DmdType emptyDmdEnv [] TopRes
botDmdType = DmdType emptyDmdEnv [] BotRes
+isTopDmdType :: DmdType -> Bool
+-- Only used on top-level types, hence the assert
+isTopDmdType (DmdType env [] TopRes) = ASSERT( isEmptyVarEnv env) True
+isTopDmdType other = False
+
isBotRes :: DmdResult -> Bool
isBotRes BotRes = True
isBotRes other = False
instance Show StrictSig where
show (StrictSig ty) = showSDoc (ppr ty)
-mkStrictSig :: Id -> Arity -> DmdType -> StrictSig
-mkStrictSig id arity dmd_ty
- = WARN( arity /= dmdTypeDepth dmd_ty, ppr id <+> (ppr arity $$ ppr dmd_ty) )
- StrictSig dmd_ty
+mkStrictSig :: DmdType -> StrictSig
+mkStrictSig dmd_ty = StrictSig dmd_ty
splitStrictSig :: StrictSig -> ([Demand], DmdResult)
splitStrictSig (StrictSig (DmdType _ dmds res)) = (dmds, res)
strictSigResInfo :: StrictSig -> DmdResult
strictSigResInfo (StrictSig (DmdType _ _ res)) = res
+isTopSig (StrictSig ty) = isTopDmdType ty
+
topSig = StrictSig topDmdType
botSig = StrictSig botDmdType
= Lazy -- L; used for unlifted types too, so that
-- A `lub` L = L
| Abs -- A
+
| Call Demand -- C(d)
| Eval -- V
- | Seq Keepity -- S/U(ds)
- Deferredness
- [Demand]
+ | Seq Keepity -- S/U/D(ds)
+ [Demand] -- S(ds) = L `both` U(ds)
+ -- D(ds) = A `lub` U(ds)
+ -- *** Invariant: these demands are never Bot or Abs
+ -- *** Invariant: if all demands are Abs, get []
+
| Err -- X
| Bot -- B
deriving( Eq )
-- Equality needed for fixpoints in DmdAnal
-data Deferredness = Now | Defer
- deriving( Eq )
-
-data Keepity = Keep | Drop
+data Keepity = Keep | Drop | Defer
deriving( Eq )
+mkSeq :: Keepity -> [Demand] -> Demand
+mkSeq k ds | all is_absent ds = Seq k []
+ | otherwise = Seq k ds
+ where
+ is_absent Abs = True
+ is_absent d = False
+
+defer :: Demand -> Demand
+-- Computes (Abs `lub` d)
+-- For the Bot case consider
+-- f x y = if ... then x else error x
+-- Then for y we get Abs `lub` Bot, and we really
+-- want Abs overall
+defer Bot = Abs
+defer Abs = Abs
+defer (Seq Keep ds) = Lazy
+defer (Seq _ ds) = Seq Defer ds
+defer d = Lazy
+
topDmd, lazyDmd, seqDmd :: Demand
-topDmd = Lazy -- The most uninformative demand
+topDmd = Lazy -- The most uninformative demand
lazyDmd = Lazy
-seqDmd = Seq Keep Now [] -- Polymorphic seq demand
+seqDmd = Seq Keep [] -- Polymorphic seq demand
evalDmd = Eval
isStrictDmd :: Demand -> Bool
-isStrictDmd Bot = True
-isStrictDmd Err = True
-isStrictDmd (Seq _ Now _) = True
-isStrictDmd Eval = True
-isStrictDmd (Call _) = True
-isStrictDmd other = False
+isStrictDmd Bot = True
+isStrictDmd Err = True
+isStrictDmd (Seq Drop _) = True -- But not Defer!
+isStrictDmd (Seq Keep _) = True
+isStrictDmd Eval = True
+isStrictDmd (Call _) = True
+isStrictDmd other = False
instance Outputable Demand where
- ppr Lazy = char 'L'
- ppr Abs = char 'A'
- ppr Eval = char 'V'
- ppr Err = char 'X'
- ppr Bot = char 'B'
- ppr (Call d) = char 'C' <> parens (ppr d)
- ppr (Seq k l []) = ppr k <> ppr l
- ppr (Seq k l ds) = ppr k <> ppr l <> parens (hcat (map ppr ds))
-
-instance Outputable Deferredness where
- ppr Now = empty
- ppr Defer = char '*'
+ ppr Lazy = char 'L'
+ ppr Abs = char 'A'
+ ppr Eval = char 'V'
+ ppr Err = char 'X'
+ ppr Bot = char 'B'
+ ppr (Call d) = char 'C' <> parens (ppr d)
+ ppr (Seq k []) = ppr k
+ ppr (Seq k ds) = ppr k <> parens (hcat (map ppr ds))
instance Outputable Keepity where
- ppr Keep = char 'S'
- ppr Drop = char 'U'
+ ppr Keep = char 'S'
+ ppr Drop = char 'U'
+ ppr Defer = char 'D'
\end{code}
projects / ghc-hetmet.git / blobdiff