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@@ -97,37 +97,37 @@ Note [Unique layout for unboxed sums] |
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Sum arities start from 2. The encoding is a bit funny: we break up the
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integral part into bitfields for the arity, an alternative index (which is
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-taken to be 0xfc in the case of the TyCon), and, in the case of a datacon, a
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-tag (used to identify the sum's TypeRep binding).
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+taken to be 0x1ffc in the case of the TyCon), and, in the case of a datacon,
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+a tag (used to identify the sum's TypeRep binding).
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This layout is chosen to remain compatible with the usual unique allocation
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for wired-in data constructors described in GHC.Types.Unique
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TyCon for sum of arity k:
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- 00000000 kkkkkkkk 11111100
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+ kkkkkkkk kkk11111 11111100
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TypeRep of TyCon for sum of arity k:
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- 00000000 kkkkkkkk 11111101
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+ kkkkkkkk kkk11111 11111101
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DataCon for sum of arity k and alternative n (zero-based):
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- 00000000 kkkkkkkk nnnnnn00
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+ kkkkkkkk kkknnnnn nnnnnn00
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TypeRep for sum DataCon of arity k and alternative n (zero-based):
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- 00000000 kkkkkkkk nnnnnn10
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+ kkkkkkkk kkknnnnn nnnnnn10
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-}
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mkSumTyConUnique :: Arity -> Unique
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mkSumTyConUnique arity =
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- assertPpr (arity <= 0x3f) (ppr arity) $
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- -- 0x3f since we only have 6 bits to encode the
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+ assertPpr (arity <= 0x7ff) (ppr arity) $
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+ -- 0x7ff since we only have 11 bits to encode the
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-- alternative
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- mkUniqueInt 'z' (arity `shiftL` 8 .|. 0xfc)
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+ mkUniqueInt 'z' (arity `shiftL` 13 .|. 0x1ffc)
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-- | Inverse of 'mkSumTyConUnique'
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isSumTyConUnique :: Unique -> Maybe Arity
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isSumTyConUnique u =
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- case (tag, n .&. 0xfc) of
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- ('z', 0xfc) -> Just (word64ToInt n `shiftR` 8)
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+ case (tag, n .&. 0x1ffc) of
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+ ('z', 0x1ffc) -> Just (word64ToInt n `shiftR` 13)
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_ -> Nothing
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where
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(tag, n) = unpkUnique u
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@@ -137,11 +137,11 @@ mkSumDataConUnique alt arity |
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| alt >= arity
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= panic ("mkSumDataConUnique: " ++ show alt ++ " >= " ++ show arity)
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| otherwise
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- = mkUniqueInt 'z' (arity `shiftL` 8 + alt `shiftL` 2) {- skip the tycon -}
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+ = mkUniqueInt 'z' (arity `shiftL` 13 + alt `shiftL` 2) {- skip the tycon -}
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getUnboxedSumName :: Int -> Name
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getUnboxedSumName n
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- | n .&. 0xfc == 0xfc
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+ | n .&. 0x1ffc == 0x1ffc
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= case tag of
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0x0 -> tyConName $ sumTyCon arity
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0x1 -> getRep $ sumTyCon arity
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@@ -155,8 +155,8 @@ getUnboxedSumName n |
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| otherwise
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= pprPanic "getUnboxedSumName" (ppr n)
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where
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- arity = n `shiftR` 8
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- alt = (n .&. 0xfc) `shiftR` 2
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+ arity = n `shiftR` 13
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+ alt = (n .&. 0x1ffc) `shiftR` 2
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tag = 0x3 .&. n
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getRep tycon =
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fromMaybe (pprPanic "getUnboxedSumName(getRep)" (ppr tycon))
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