    {-# LANGUAGE CPP #-}

    -- | This is where we define a mapping from Uniques to their associated
    -- known-key Names for things associated with tuples and sums. We use this
    -- mapping while deserializing known-key Names in interface file symbol tables,
    -- which are encoded as their Unique. See Note [Symbol table representation of
    -- names] for details.
    --

    module GHC.Builtin.Uniques
        ( -- * Looking up known-key names
          knownUniqueName

          -- * Getting the 'Unique's of 'Name's
          -- ** Anonymous sums
        , mkSumTyConUnique
        , mkSumDataConUnique
          -- ** Tuples
          -- *** Vanilla
        , mkTupleTyConUnique
        , mkTupleDataConUnique
          -- *** Constraint
        , mkCTupleTyConUnique
        , mkCTupleDataConUnique
        , mkCTupleSelIdUnique

          -- ** Making built-in uniques
        , mkAlphaTyVarUnique
        , mkPrimOpIdUnique, mkPrimOpWrapperUnique
        , mkPreludeMiscIdUnique, mkPreludeDataConUnique
        , mkPreludeTyConUnique, mkPreludeClassUnique
        , mkCoVarUnique

        , mkVarOccUnique, mkDataOccUnique, mkTvOccUnique, mkTcOccUnique
        , mkRegSingleUnique, mkRegPairUnique, mkRegClassUnique, mkRegSubUnique
        , mkCostCentreUnique

        , mkBuiltinUnique
        , mkPseudoUniqueD
        , mkPseudoUniqueE
        , mkPseudoUniqueH

          -- ** Deriving uniquesc
          -- *** From TyCon name uniques
        , tyConRepNameUnique
          -- *** From DataCon name uniques
        , dataConWorkerUnique, dataConTyRepNameUnique

        , initTyVarUnique
        , initExitJoinUnique

        ) where

    #include "HsVersions.h"

    import GHC.Prelude

    import {-# SOURCE #-} GHC.Builtin.Types
    import {-# SOURCE #-} GHC.Core.TyCon
    import {-# SOURCE #-} GHC.Core.DataCon
    import {-# SOURCE #-} GHC.Types.Id
    import {-# SOURCE #-} GHC.Types.Name
    import GHC.Types.Basic
    import GHC.Types.Unique
    import GHC.Data.FastString

    import GHC.Utils.Outputable
    import GHC.Utils.Misc
    import GHC.Utils.Panic

    import Data.Maybe

    -- | Get the 'Name' associated with a known-key 'Unique'.
    knownUniqueName :: Unique -> Maybe Name
    knownUniqueName :: Unique -> Maybe Name
    knownUniqueName Unique
    u =
        case Char
    tag of
          Char
    'z' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Int -> Name
    getUnboxedSumName Int
    n
          Char
    '4' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> Name
    getTupleTyConName Boxity
    Boxed Int
    n
          Char
    '5' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> Name
    getTupleTyConName Boxity
    Unboxed Int
    n
          Char
    '7' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> Name
    getTupleDataConName Boxity
    Boxed Int
    n
          Char
    '8' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> Name
    getTupleDataConName Boxity
    Unboxed Int
    n
          Char
    'j' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Int -> Name
    getCTupleSelIdName Int
    n
          Char
    'k' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Int -> Name
    getCTupleTyConName Int
    n
          Char
    'm' -> forall a. a -> Maybe a
    Just forall a b. (a -> b) -> a -> b
    $ Int -> Name
    getCTupleDataConName Int
    n
          Char
    _   -> forall a. Maybe a
    Nothing
      where
        (Char
    tag, Int
    n) = Unique -> (Char, Int)
    unpkUnique Unique
    u

    {-
    Note [Unique layout for unboxed sums]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Sum arities start from 2. The encoding is a bit funny: we break up the
    integral part into bitfields for the arity, an alternative index (which is
    taken to be 0xfc in the case of the TyCon), and, in the case of a datacon, a
    tag (used to identify the sum's TypeRep binding).

    This layout is chosen to remain compatible with the usual unique allocation
    for wired-in data constructors described in GHC.Types.Unique

    TyCon for sum of arity k:
      00000000 kkkkkkkk 11111100

    TypeRep of TyCon for sum of arity k:
      00000000 kkkkkkkk 11111101

    DataCon for sum of arity k and alternative n (zero-based):
      00000000 kkkkkkkk nnnnnn00

    TypeRep for sum DataCon of arity k and alternative n (zero-based):
      00000000 kkkkkkkk nnnnnn10
    -}

    mkSumTyConUnique :: Arity -> Unique
    mkSumTyConUnique :: Int -> Unique
    mkSumTyConUnique Int
    arity =
        ASSERT(arity < 0x3f) -- 0x3f since we only have 6 bits to encode the
                             -- alternative
        Char -> Int -> Unique
    mkUnique Char
    'z' (Int
    arity forall a. Bits a => a -> Int -> a
    `shiftL` Int
    8 forall a. Bits a => a -> a -> a
    .|. Int
    0xfc)

    mkSumDataConUnique :: ConTagZ -> Arity -> Unique
    mkSumDataConUnique :: Int -> Int -> Unique
    mkSumDataConUnique Int
    alt Int
    arity
      | Int
    alt forall a. Ord a => a -> a -> Bool
    >= Int
    arity
      = forall a. String -> a
    panic (String
    "mkSumDataConUnique: " forall a. [a] -> [a] -> [a]
    ++ forall a. Show a => a -> String
    show Int
    alt forall a. [a] -> [a] -> [a]
    ++ String
    " >= " forall a. [a] -> [a] -> [a]
    ++ forall a. Show a => a -> String
    show Int
    arity)
      | Bool
    otherwise
      = Char -> Int -> Unique
    mkUnique Char
    'z' (Int
    arity forall a. Bits a => a -> Int -> a
    `shiftL` Int
    8 forall a. Num a => a -> a -> a
    + Int
    alt forall a. Bits a => a -> Int -> a
    `shiftL` Int
    2) {- skip the tycon -}

    getUnboxedSumName :: Int -> Name
    getUnboxedSumName :: Int -> Name
    getUnboxedSumName Int
    n
      | Int
    n forall a. Bits a => a -> a -> a
    .&. Int
    0xfc forall a. Eq a => a -> a -> Bool
    == Int
    0xfc
      = case Int
    tag of
          Int
    0x0 -> TyCon -> Name
    tyConName forall a b. (a -> b) -> a -> b
    $ Int -> TyCon
    sumTyCon Int
    arity
          Int
    0x1 -> TyCon -> Name
    getRep forall a b. (a -> b) -> a -> b
    $ Int -> TyCon
    sumTyCon Int
    arity
          Int
    _   -> forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "getUnboxedSumName: invalid tag" (forall a. Outputable a => a -> SDoc
    ppr Int
    tag)
      | Int
    tag forall a. Eq a => a -> a -> Bool
    == Int
    0x0
      = DataCon -> Name
    dataConName forall a b. (a -> b) -> a -> b
    $ Int -> Int -> DataCon
    sumDataCon (Int
    alt forall a. Num a => a -> a -> a
    + Int
    1) Int
    arity
      | Int
    tag forall a. Eq a => a -> a -> Bool
    == Int
    0x1
      = forall a. NamedThing a => a -> Name
    getName forall a b. (a -> b) -> a -> b
    $ DataCon -> Id
    dataConWrapId forall a b. (a -> b) -> a -> b
    $ Int -> Int -> DataCon
    sumDataCon (Int
    alt forall a. Num a => a -> a -> a
    + Int
    1) Int
    arity
      | Int
    tag forall a. Eq a => a -> a -> Bool
    == Int
    0x2
      = TyCon -> Name
    getRep forall a b. (a -> b) -> a -> b
    $ DataCon -> TyCon
    promoteDataCon forall a b. (a -> b) -> a -> b
    $ Int -> Int -> DataCon
    sumDataCon (Int
    alt forall a. Num a => a -> a -> a
    + Int
    1) Int
    arity
      | Bool
    otherwise
      = forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "getUnboxedSumName" (forall a. Outputable a => a -> SDoc
    ppr Int
    n)
      where
        arity :: Int
    arity = Int
    n forall a. Bits a => a -> Int -> a
    `shiftR` Int
    8
        alt :: Int
    alt = (Int
    n forall a. Bits a => a -> a -> a
    .&. Int
    0xfc) forall a. Bits a => a -> Int -> a
    `shiftR` Int
    2
        tag :: Int
    tag = Int
    0x3 forall a. Bits a => a -> a -> a
    .&. Int
    n
        getRep :: TyCon -> Name
    getRep TyCon
    tycon =
            forall a. a -> Maybe a -> a
    fromMaybe (forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "getUnboxedSumName(getRep)" (forall a. Outputable a => a -> SDoc
    ppr TyCon
    tycon))
            forall a b. (a -> b) -> a -> b
    $ TyCon -> Maybe Name
    tyConRepName_maybe TyCon
    tycon

    -- Note [Uniques for tuple type and data constructors]
    -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    --
    -- Wired-in type constructor keys occupy *two* slots:
    --    * u: the TyCon itself
    --    * u+1: the TyConRepName of the TyCon
    --
    -- Wired-in tuple data constructor keys occupy *three* slots:
    --    * u: the DataCon itself
    --    * u+1: its worker Id
    --    * u+2: the TyConRepName of the promoted TyCon

    {-
    Note [Unique layout for constraint tuple selectors]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Constraint tuples, like boxed and unboxed tuples, have their type and data
    constructor Uniques wired in (see
    Note [Uniques for tuple type and data constructors]). Constraint tuples are
    somewhat more involved, however. For a boxed or unboxed n-tuple, we need:

    * A Unique for the type constructor, and
    * A Unique for the data constructor

    With a constraint n-tuple, however, we need:

    * A Unique for the type constructor,
    * A Unique for the data constructor, and
    * A Unique for each of the n superclass selectors

    To pick a concrete example (n = 2), the binary constraint tuple has a type
    constructor and data constructor (%,%) along with superclass selectors
    $p1(%,%) and $p2(%,%).

    Just as we wire in the Uniques for constraint tuple type constructors and data
    constructors, we wish to wire in the Uniques for the superclass selectors as
    well. Not only does this make everything consistent, it also avoids a
    compile-time performance penalty whenever GHC.Classes is loaded from an
    interface file. This is because GHC.Classes defines constraint tuples as class
    definitions, and if these classes weren't wired in, then loading GHC.Classes
    would also load every single constraint tuple type constructor, data
    constructor, and superclass selector. See #18635.

    We encode the Uniques for constraint tuple superclass selectors as follows. The
    integral part of the Unique is broken up into bitfields for the arity and the
    position of the superclass. Given a selector for a constraint tuple with
    arity n (zero-based) and position k (where 1 <= k <= n), its Unique will look
    like:

      00000000 nnnnnnnn kkkkkkkk

    We can use bit-twiddling tricks to access the arity and position with
    cTupleSelIdArityBits and cTupleSelIdPosBitmask, respectively.

    This pattern bears a certain resemblance to the way that the Uniques for
    unboxed sums are encoded. This is because for a unboxed sum of arity n, there
    are n corresponding data constructors, each with an alternative position k.
    Similarly, for a constraint tuple of arity n, there are n corresponding
    superclass selectors. Reading Note [Unique layout for unboxed sums] will
    instill an appreciation for how the encoding for constraint tuple superclass
    selector Uniques takes inspiration from the encoding for unboxed sum Uniques.
    -}

    mkCTupleTyConUnique :: Arity -> Unique
    mkCTupleTyConUnique :: Int -> Unique
    mkCTupleTyConUnique Int
    a = Char -> Int -> Unique
    mkUnique Char
    'k' (Int
    2forall a. Num a => a -> a -> a
    *Int
    a)

    mkCTupleDataConUnique :: Arity -> Unique
    mkCTupleDataConUnique :: Int -> Unique
    mkCTupleDataConUnique Int
    a = Char -> Int -> Unique
    mkUnique Char
    'm' (Int
    3forall a. Num a => a -> a -> a
    *Int
    a)

    mkCTupleSelIdUnique :: ConTagZ -> Arity -> Unique
    mkCTupleSelIdUnique :: Int -> Int -> Unique
    mkCTupleSelIdUnique Int
    sc_pos Int
    arity
      | Int
    sc_pos forall a. Ord a => a -> a -> Bool
    >= Int
    arity
      = forall a. String -> a
    panic (String
    "mkCTupleSelIdUnique: " forall a. [a] -> [a] -> [a]
    ++ forall a. Show a => a -> String
    show Int
    sc_pos forall a. [a] -> [a] -> [a]
    ++ String
    " >= " forall a. [a] -> [a] -> [a]
    ++ forall a. Show a => a -> String
    show Int
    arity)
      | Bool
    otherwise
      = Char -> Int -> Unique
    mkUnique Char
    'j' (Int
    arity forall a. Bits a => a -> Int -> a
    `shiftL` Int
    cTupleSelIdArityBits forall a. Num a => a -> a -> a
    + Int
    sc_pos)

    getCTupleTyConName :: Int -> Name
    getCTupleTyConName :: Int -> Name
    getCTupleTyConName Int
    n =
        case Int
    n forall a. Integral a => a -> a -> (a, a)
    `divMod` Int
    2 of
          (Int
    arity, Int
    0) -> Int -> Name
    cTupleTyConName Int
    arity
          (Int
    arity, Int
    1) -> Name -> Name
    mkPrelTyConRepName forall a b. (a -> b) -> a -> b
    $ Int -> Name
    cTupleTyConName Int
    arity
          (Int, Int)
    _          -> forall a. String -> a
    panic String
    "getCTupleTyConName: impossible"

    getCTupleDataConName :: Int -> Name
    getCTupleDataConName :: Int -> Name
    getCTupleDataConName Int
    n =
        case Int
    n forall a. Integral a => a -> a -> (a, a)
    `divMod` Int
    3 of
          (Int
    arity,  Int
    0) -> Int -> Name
    cTupleDataConName Int
    arity
          (Int
    arity,  Int
    1) -> forall a. NamedThing a => a -> Name
    getName forall a b. (a -> b) -> a -> b
    $ DataCon -> Id
    dataConWrapId forall a b. (a -> b) -> a -> b
    $ Int -> DataCon
    cTupleDataCon Int
    arity
          (Int
    arity,  Int
    2) -> Name -> Name
    mkPrelTyConRepName forall a b. (a -> b) -> a -> b
    $ Int -> Name
    cTupleDataConName Int
    arity
          (Int, Int)
    _           -> forall a. String -> a
    panic String
    "getCTupleDataConName: impossible"

    getCTupleSelIdName :: Int -> Name
    getCTupleSelIdName :: Int -> Name
    getCTupleSelIdName Int
    n = Int -> Int -> Name
    cTupleSelIdName (Int
    sc_pos forall a. Num a => a -> a -> a
    + Int
    1) Int
    arity
      where
        arity :: Int
    arity  = Int
    n forall a. Bits a => a -> Int -> a
    `shiftR` Int
    cTupleSelIdArityBits
        sc_pos :: Int
    sc_pos = Int
    n forall a. Bits a => a -> a -> a
    .&. Int
    cTupleSelIdPosBitmask

    -- Given the arity of a constraint tuple, this is the number of bits by which
    -- one must shift it to the left in order to encode the arity in the Unique
    -- of a superclass selector for that constraint tuple. Alternatively, given the
    -- Unique for a constraint tuple superclass selector, this is the number of
    -- bits by which one must shift it to the right to retrieve the arity of the
    -- constraint tuple. See Note [Unique layout for constraint tuple selectors].
    cTupleSelIdArityBits :: Int
    cTupleSelIdArityBits :: Int
    cTupleSelIdArityBits = Int
    8

    -- Given the Unique for a constraint tuple superclass selector, one can
    -- retrieve the position of the selector by ANDing this mask, which will
    -- clear all but the eight least significant bits.
    -- See Note [Unique layout for constraint tuple selectors].
    cTupleSelIdPosBitmask :: Int
    cTupleSelIdPosBitmask :: Int
    cTupleSelIdPosBitmask = Int
    0xff

    --------------------------------------------------
    -- Normal tuples

    mkTupleDataConUnique :: Boxity -> Arity -> Unique
    mkTupleDataConUnique :: Boxity -> Int -> Unique
    mkTupleDataConUnique Boxity
    Boxed          Int
    a = Char -> Int -> Unique
    mkUnique Char
    '7' (Int
    3forall a. Num a => a -> a -> a
    *Int
    a)    -- may be used in C labels
    mkTupleDataConUnique Boxity
    Unboxed        Int
    a = Char -> Int -> Unique
    mkUnique Char
    '8' (Int
    3forall a. Num a => a -> a -> a
    *Int
    a)

    mkTupleTyConUnique :: Boxity -> Arity -> Unique
    mkTupleTyConUnique :: Boxity -> Int -> Unique
    mkTupleTyConUnique Boxity
    Boxed           Int
    a  = Char -> Int -> Unique
    mkUnique Char
    '4' (Int
    2forall a. Num a => a -> a -> a
    *Int
    a)
    mkTupleTyConUnique Boxity
    Unboxed         Int
    a  = Char -> Int -> Unique
    mkUnique Char
    '5' (Int
    2forall a. Num a => a -> a -> a
    *Int
    a)

    getTupleTyConName :: Boxity -> Int -> Name
    getTupleTyConName :: Boxity -> Int -> Name
    getTupleTyConName Boxity
    boxity Int
    n =
        case Int
    n forall a. Integral a => a -> a -> (a, a)
    `divMod` Int
    2 of
          (Int
    arity, Int
    0) -> TyCon -> Name
    tyConName forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> TyCon
    tupleTyCon Boxity
    boxity Int
    arity
          (Int
    arity, Int
    1) -> forall a. a -> Maybe a -> a
    fromMaybe (forall a. String -> a
    panic String
    "getTupleTyConName")
                        forall a b. (a -> b) -> a -> b
    $ TyCon -> Maybe Name
    tyConRepName_maybe forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> TyCon
    tupleTyCon Boxity
    boxity Int
    arity
          (Int, Int)
    _          -> forall a. String -> a
    panic String
    "getTupleTyConName: impossible"

    getTupleDataConName :: Boxity -> Int -> Name
    getTupleDataConName :: Boxity -> Int -> Name
    getTupleDataConName Boxity
    boxity Int
    n =
        case Int
    n forall a. Integral a => a -> a -> (a, a)
    `divMod` Int
    3 of
          (Int
    arity, Int
    0) -> DataCon -> Name
    dataConName forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> DataCon
    tupleDataCon Boxity
    boxity Int
    arity
          (Int
    arity, Int
    1) -> Id -> Name
    idName forall a b. (a -> b) -> a -> b
    $ DataCon -> Id
    dataConWorkId forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> DataCon
    tupleDataCon Boxity
    boxity Int
    arity
          (Int
    arity, Int
    2) -> forall a. a -> Maybe a -> a
    fromMaybe (forall a. String -> a
    panic String
    "getTupleDataCon")
                        forall a b. (a -> b) -> a -> b
    $ TyCon -> Maybe Name
    tyConRepName_maybe forall a b. (a -> b) -> a -> b
    $ Boxity -> Int -> TyCon
    promotedTupleDataCon Boxity
    boxity Int
    arity
          (Int, Int)
    _          -> forall a. String -> a
    panic String
    "getTupleDataConName: impossible"

    {-
    Note [Uniques for wired-in prelude things and known masks]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Allocation of unique supply characters:
            v,t,u : for renumbering value-, type- and usage- vars.
            B:   builtin
            C-E: pseudo uniques     (used in native-code generator)
            I:   GHCi evaluation
            X:   uniques from mkLocalUnique
            _:   unifiable tyvars   (above)
            0-9: prelude things below
                 (no numbers left any more..)
            ::   (prelude) parallel array data constructors

            other a-z: lower case chars for unique supplies.  Used so far:

            a       TypeChecking?
            c       StgToCmm/Renamer
            d       desugarer
            f       AbsC flattener
            g       SimplStg
            i       TypeChecking interface files
            j       constraint tuple superclass selectors
            k       constraint tuple tycons
            m       constraint tuple datacons
            n       Native/LLVM codegen
            r       Hsc name cache
            s       simplifier
            u       Cmm pipeline
            y       GHCi bytecode generator
            z       anonymous sums
    -}

    mkAlphaTyVarUnique     :: Int -> Unique
    mkPreludeClassUnique   :: Int -> Unique
    mkPrimOpIdUnique       :: Int -> Unique
    -- See Note [Primop wrappers] in GHC.Builtin.PrimOps.
    mkPrimOpWrapperUnique  :: Int -> Unique
    mkPreludeMiscIdUnique  :: Int -> Unique
    mkCoVarUnique          :: Int -> Unique

    mkAlphaTyVarUnique :: Int -> Unique
    mkAlphaTyVarUnique   Int
    i = Char -> Int -> Unique
    mkUnique Char
    '1' Int
    i
    mkCoVarUnique :: Int -> Unique
    mkCoVarUnique        Int
    i = Char -> Int -> Unique
    mkUnique Char
    'g' Int
    i
    mkPreludeClassUnique :: Int -> Unique
    mkPreludeClassUnique Int
    i = Char -> Int -> Unique
    mkUnique Char
    '2' Int
    i

    --------------------------------------------------
    mkPrimOpIdUnique :: Int -> Unique
    mkPrimOpIdUnique Int
    op         = Char -> Int -> Unique
    mkUnique Char
    '9' (Int
    2forall a. Num a => a -> a -> a
    *Int
    op)
    mkPrimOpWrapperUnique :: Int -> Unique
    mkPrimOpWrapperUnique Int
    op    = Char -> Int -> Unique
    mkUnique Char
    '9' (Int
    2forall a. Num a => a -> a -> a
    *Int
    opforall a. Num a => a -> a -> a
    +Int
    1)
    mkPreludeMiscIdUnique :: Int -> Unique
    mkPreludeMiscIdUnique  Int
    i    = Char -> Int -> Unique
    mkUnique Char
    '0' Int
    i

    -- The "tyvar uniques" print specially nicely: a, b, c, etc.
    -- See pprUnique for details

    initTyVarUnique :: Unique
    initTyVarUnique :: Unique
    initTyVarUnique = Char -> Int -> Unique
    mkUnique Char
    't' Int
    0

    mkPseudoUniqueD, mkPseudoUniqueE, mkPseudoUniqueH,
      mkBuiltinUnique :: Int -> Unique

    mkBuiltinUnique :: Int -> Unique
    mkBuiltinUnique Int
    i = Char -> Int -> Unique
    mkUnique Char
    'B' Int
    i
    mkPseudoUniqueD :: Int -> Unique
    mkPseudoUniqueD Int
    i = Char -> Int -> Unique
    mkUnique Char
    'D' Int
    i -- used in NCG for getUnique on RealRegs
    mkPseudoUniqueE :: Int -> Unique
    mkPseudoUniqueE Int
    i = Char -> Int -> Unique
    mkUnique Char
    'E' Int
    i -- used in NCG spiller to create spill VirtualRegs
    mkPseudoUniqueH :: Int -> Unique
    mkPseudoUniqueH Int
    i = Char -> Int -> Unique
    mkUnique Char
    'H' Int
    i -- used in NCG spiller to create spill VirtualRegs

    mkRegSingleUnique, mkRegPairUnique, mkRegSubUnique, mkRegClassUnique :: Int -> Unique
    mkRegSingleUnique :: Int -> Unique
    mkRegSingleUnique = Char -> Int -> Unique
    mkUnique Char
    'R'
    mkRegSubUnique :: Int -> Unique
    mkRegSubUnique    = Char -> Int -> Unique
    mkUnique Char
    'S'
    mkRegPairUnique :: Int -> Unique
    mkRegPairUnique   = Char -> Int -> Unique
    mkUnique Char
    'P'
    mkRegClassUnique :: Int -> Unique
    mkRegClassUnique  = Char -> Int -> Unique
    mkUnique Char
    'L'

    mkCostCentreUnique :: Int -> Unique
    mkCostCentreUnique :: Int -> Unique
    mkCostCentreUnique = Char -> Int -> Unique
    mkUnique Char
    'C'

    mkVarOccUnique, mkDataOccUnique, mkTvOccUnique, mkTcOccUnique :: FastString -> Unique
    -- See Note [The Unique of an OccName] in GHC.Types.Name.Occurrence
    mkVarOccUnique :: FastString -> Unique
    mkVarOccUnique  FastString
    fs = Char -> Int -> Unique
    mkUnique Char
    'i' (FastString -> Int
    uniqueOfFS FastString
    fs)
    mkDataOccUnique :: FastString -> Unique
    mkDataOccUnique FastString
    fs = Char -> Int -> Unique
    mkUnique Char
    'd' (FastString -> Int
    uniqueOfFS FastString
    fs)
    mkTvOccUnique :: FastString -> Unique
    mkTvOccUnique   FastString
    fs = Char -> Int -> Unique
    mkUnique Char
    'v' (FastString -> Int
    uniqueOfFS FastString
    fs)
    mkTcOccUnique :: FastString -> Unique
    mkTcOccUnique   FastString
    fs = Char -> Int -> Unique
    mkUnique Char
    'c' (FastString -> Int
    uniqueOfFS FastString
    fs)

    initExitJoinUnique :: Unique
    initExitJoinUnique :: Unique
    initExitJoinUnique = Char -> Int -> Unique
    mkUnique Char
    's' Int
    0

    --------------------------------------------------
    -- Wired-in type constructor keys occupy *two* slots:
    --    * u: the TyCon itself
    --    * u+1: the TyConRepName of the TyCon

    mkPreludeTyConUnique   :: Int -> Unique
    mkPreludeTyConUnique :: Int -> Unique
    mkPreludeTyConUnique Int
    i                = Char -> Int -> Unique
    mkUnique Char
    '3' (Int
    2forall a. Num a => a -> a -> a
    *Int
    i)

    tyConRepNameUnique :: Unique -> Unique
    tyConRepNameUnique :: Unique -> Unique
    tyConRepNameUnique  Unique
    u = Unique -> Unique
    incrUnique Unique
    u

    --------------------------------------------------
    -- Wired-in data constructor keys occupy *three* slots:
    --    * u: the DataCon itself
    --    * u+1: its worker Id
    --    * u+2: the TyConRepName of the promoted TyCon
    -- Prelude data constructors are too simple to need wrappers.

    mkPreludeDataConUnique :: Arity -> Unique
    mkPreludeDataConUnique :: Int -> Unique
    mkPreludeDataConUnique Int
    i              = Char -> Int -> Unique
    mkUnique Char
    '6' (Int
    3forall a. Num a => a -> a -> a
    *Int
    i)    -- Must be alphabetic

    --------------------------------------------------
    dataConTyRepNameUnique, dataConWorkerUnique :: Unique -> Unique
    dataConWorkerUnique :: Unique -> Unique
    dataConWorkerUnique  Unique
    u = Unique -> Unique
    incrUnique Unique
    u
    dataConTyRepNameUnique :: Unique -> Unique
    dataConTyRepNameUnique Unique
    u = Unique -> Int -> Unique
    stepUnique Unique
    u Int
    2