    {-# LANGUAGE RecordWildCards #-}
    {-# LANGUAGE LambdaCase #-}
    {-# LANGUAGE MultiParamTypeClasses #-}
    {-# LANGUAGE FlexibleInstances #-}

    -----------------------------------------------------------------------------
    --
    -- Stg to C-- code generation:
    --
    -- The types   LambdaFormInfo
    --             ClosureInfo
    --
    -- Nothing monadic in here!
    --
    -----------------------------------------------------------------------------

    module GHC.StgToCmm.Closure (
            DynTag,  tagForCon, isSmallFamily,

            idPrimRep, isVoidRep, isGcPtrRep, addIdReps, addArgReps,
            argPrimRep,

            NonVoid(..), fromNonVoid, nonVoidIds, nonVoidStgArgs,
            assertNonVoidIds, assertNonVoidStgArgs,

            -- * LambdaFormInfo
            LambdaFormInfo,         -- Abstract
            StandardFormInfo,        -- ...ditto...
            mkLFThunk, mkLFReEntrant, mkConLFInfo, mkSelectorLFInfo,
            mkApLFInfo, mkLFImported, mkLFArgument, mkLFLetNoEscape,
            mkLFStringLit,
            lfDynTag,
            isLFThunk, isLFReEntrant, lfUpdatable,

            -- * Used by other modules
            CgLoc(..), CallMethod(..),
            nodeMustPointToIt, isKnownFun, funTag, tagForArity,
            getCallMethod,

            -- * ClosureInfo
            ClosureInfo,
            mkClosureInfo,
            mkCmmInfo,

            -- ** Inspection
            closureLFInfo, closureName,

            -- ** Labels
            -- These just need the info table label
            closureInfoLabel, staticClosureLabel,
            closureSlowEntryLabel, closureLocalEntryLabel,

            -- ** Predicates
            -- These are really just functions on LambdaFormInfo
            closureUpdReqd,
            closureReEntrant, closureFunInfo,
            isToplevClosure,

            blackHoleOnEntry,  -- Needs LambdaFormInfo and SMRep
            isStaticClosure,   -- Needs SMPre

            -- * InfoTables
            mkDataConInfoTable,
            cafBlackHoleInfoTable,
            indStaticInfoTable,
            staticClosureNeedsLink,
            mkClosureInfoTableLabel
        ) where

    import GHC.Prelude
    import GHC.Platform
    import GHC.Platform.Profile

    import GHC.Stg.Syntax
    import GHC.Runtime.Heap.Layout
    import GHC.Cmm
    import GHC.Cmm.Utils
    import GHC.StgToCmm.Types
    import GHC.StgToCmm.Sequel

    import GHC.Types.CostCentre
    import GHC.Cmm.BlockId
    import GHC.Cmm.CLabel
    import GHC.Types.Id
    import GHC.Types.Id.Info
    import GHC.Core.DataCon
    import GHC.Types.Name
    import GHC.Core.Type
    import GHC.Core.TyCo.Rep
    import GHC.Tc.Utils.TcType
    import GHC.Core.TyCon
    import GHC.Types.RepType
    import GHC.Types.Basic
    import GHC.Utils.Outputable
    import GHC.Utils.Panic
    import GHC.Utils.Panic.Plain
    import GHC.Utils.Misc

    import Data.Coerce (coerce)
    import qualified Data.ByteString.Char8 as BS8
    import GHC.StgToCmm.Config
    import GHC.Stg.InferTags.TagSig (isTaggedSig)

    -----------------------------------------------------------------------------
    --                Data types and synonyms
    -----------------------------------------------------------------------------

    -- These data types are mostly used by other modules, especially
    -- GHC.StgToCmm.Monad, but we define them here because some functions in this
    -- module need to have access to them as well

    data CgLoc
      = CmmLoc CmmExpr      -- A stable CmmExpr; that is, one not mentioning
                            -- Hp, so that it remains valid across calls

      | LneLoc BlockId [LocalReg]             -- A join point
            -- A join point (= let-no-escape) should only
            -- be tail-called, and in a saturated way.
            -- To tail-call it, assign to these locals,
            -- and branch to the block id

    instance OutputableP Platform CgLoc where
       pdoc :: Platform -> CgLoc -> SDoc
    pdoc = Platform -> CgLoc -> SDoc
    pprCgLoc

    pprCgLoc :: Platform -> CgLoc -> SDoc
    pprCgLoc :: Platform -> CgLoc -> SDoc
    pprCgLoc Platform
    platform = \case
       CmmLoc CmmExpr
    e    -> String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "cmm" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Platform -> CmmExpr -> SDoc
    forall env a. OutputableP env a => env -> a -> SDoc
    pdoc Platform
    platform CmmExpr
    e
       LneLoc BlockId
    b [LocalReg]
    rs -> String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "lne" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> BlockId -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr BlockId
    b SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> [LocalReg] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [LocalReg]
    rs

    -- used by ticky profiling
    isKnownFun :: LambdaFormInfo -> Bool
    isKnownFun :: LambdaFormInfo -> Bool
    isKnownFun LFReEntrant{} = Bool
    True
    isKnownFun LambdaFormInfo
    LFLetNoEscape = Bool
    True
    isKnownFun LambdaFormInfo
    _             = Bool
    False

    -------------------------------------
    --        Non-void types
    -------------------------------------
    -- We frequently need the invariant that an Id or a an argument
    -- is of a non-void type. This type is a witness to the invariant.

    newtype NonVoid a = NonVoid a
      deriving (NonVoid a -> NonVoid a -> Bool
    (NonVoid a -> NonVoid a -> Bool)
    -> (NonVoid a -> NonVoid a -> Bool) -> Eq (NonVoid a)
    forall a. Eq a => NonVoid a -> NonVoid a -> Bool
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: forall a. Eq a => NonVoid a -> NonVoid a -> Bool
    == :: NonVoid a -> NonVoid a -> Bool
    $c/= :: forall a. Eq a => NonVoid a -> NonVoid a -> Bool
    /= :: NonVoid a -> NonVoid a -> Bool
    Eq, Int -> NonVoid a -> ShowS
    [NonVoid a] -> ShowS
    NonVoid a -> String
    (Int -> NonVoid a -> ShowS)
    -> (NonVoid a -> String)
    -> ([NonVoid a] -> ShowS)
    -> Show (NonVoid a)
    forall a. Show a => Int -> NonVoid a -> ShowS
    forall a. Show a => [NonVoid a] -> ShowS
    forall a. Show a => NonVoid a -> String
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    $cshowsPrec :: forall a. Show a => Int -> NonVoid a -> ShowS
    showsPrec :: Int -> NonVoid a -> ShowS
    $cshow :: forall a. Show a => NonVoid a -> String
    show :: NonVoid a -> String
    $cshowList :: forall a. Show a => [NonVoid a] -> ShowS
    showList :: [NonVoid a] -> ShowS
    Show)

    fromNonVoid :: NonVoid a -> a
    fromNonVoid :: forall a. NonVoid a -> a
    fromNonVoid (NonVoid a
    a) = a
    a

    instance (Outputable a) => Outputable (NonVoid a) where
      ppr :: NonVoid a -> SDoc
    ppr (NonVoid a
    a) = a -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr a
    a

    nonVoidIds :: [Id] -> [NonVoid Id]
    nonVoidIds :: [Id] -> [NonVoid Id]
    nonVoidIds [Id]
    ids = [Id -> NonVoid Id
    forall a. a -> NonVoid a
    NonVoid Id
    id | Id
    id <- [Id]
    ids, Bool -> Bool
    not ((() :: Constraint) => Type -> Bool
    Type -> Bool
    isZeroBitTy (Id -> Type
    idType Id
    id))]

    -- | Used in places where some invariant ensures that all these Ids are
    -- non-void; e.g. constructor field binders in case expressions.
    -- See Note [Post-unarisation invariants] in "GHC.Stg.Unarise".
    assertNonVoidIds :: [Id] -> [NonVoid Id]
    assertNonVoidIds :: [Id] -> [NonVoid Id]
    assertNonVoidIds [Id]
    ids = Bool -> [NonVoid Id] -> [NonVoid Id]
    forall a. HasCallStack => Bool -> a -> a
    assert (Bool -> Bool
    not ((Id -> Bool) -> [Id] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    any ((() :: Constraint) => Type -> Bool
    Type -> Bool
    isZeroBitTy (Type -> Bool) -> (Id -> Type) -> Id -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Id -> Type
    idType) [Id]
    ids)) ([NonVoid Id] -> [NonVoid Id]) -> [NonVoid Id] -> [NonVoid Id]
    forall a b. (a -> b) -> a -> b
    $
                           [Id] -> [NonVoid Id]
    forall a b. Coercible a b => a -> b
    coerce [Id]
    ids

    nonVoidStgArgs :: [StgArg] -> [NonVoid StgArg]
    nonVoidStgArgs :: [StgArg] -> [NonVoid StgArg]
    nonVoidStgArgs [StgArg]
    args = [StgArg -> NonVoid StgArg
    forall a. a -> NonVoid a
    NonVoid StgArg
    arg | StgArg
    arg <- [StgArg]
    args, Bool -> Bool
    not ((() :: Constraint) => Type -> Bool
    Type -> Bool
    isZeroBitTy (StgArg -> Type
    stgArgType StgArg
    arg))]

    -- | Used in places where some invariant ensures that all these arguments are
    -- non-void; e.g. constructor arguments.
    -- See Note [Post-unarisation invariants] in "GHC.Stg.Unarise".
    assertNonVoidStgArgs :: [StgArg] -> [NonVoid StgArg]
    assertNonVoidStgArgs :: [StgArg] -> [NonVoid StgArg]
    assertNonVoidStgArgs [StgArg]
    args = Bool -> [NonVoid StgArg] -> [NonVoid StgArg]
    forall a. HasCallStack => Bool -> a -> a
    assert (Bool -> Bool
    not ((StgArg -> Bool) -> [StgArg] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    any ((() :: Constraint) => Type -> Bool
    Type -> Bool
    isZeroBitTy (Type -> Bool) -> (StgArg -> Type) -> StgArg -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . StgArg -> Type
    stgArgType) [StgArg]
    args)) ([NonVoid StgArg] -> [NonVoid StgArg])
    -> [NonVoid StgArg] -> [NonVoid StgArg]
    forall a b. (a -> b) -> a -> b
    $
                                [StgArg] -> [NonVoid StgArg]
    forall a b. Coercible a b => a -> b
    coerce [StgArg]
    args

    -----------------------------------------------------------------------------
    --                Representations
    -----------------------------------------------------------------------------

    -- Why are these here?

    -- | Assumes that there is precisely one 'PrimRep' of the type. This assumption
    -- holds after unarise.
    -- See Note [Post-unarisation invariants]
    idPrimRep :: Id -> PrimRep
    idPrimRep :: Id -> PrimRep
    idPrimRep Id
    id = (() :: Constraint) => Type -> PrimRep
    Type -> PrimRep
    typePrimRep1 (Id -> Type
    idType Id
    id)
        -- See also Note [VoidRep] in GHC.Types.RepType

    -- | Assumes that Ids have one PrimRep, which holds after unarisation.
    -- See Note [Post-unarisation invariants]
    addIdReps :: [NonVoid Id] -> [NonVoid (PrimRep, Id)]
    addIdReps :: [NonVoid Id] -> [NonVoid (PrimRep, Id)]
    addIdReps = (NonVoid Id -> NonVoid (PrimRep, Id))
    -> [NonVoid Id] -> [NonVoid (PrimRep, Id)]
    forall a b. (a -> b) -> [a] -> [b]
    map (\NonVoid Id
    id -> let id' :: Id
    id' = NonVoid Id -> Id
    forall a. NonVoid a -> a
    fromNonVoid NonVoid Id
    id
                             in (PrimRep, Id) -> NonVoid (PrimRep, Id)
    forall a. a -> NonVoid a
    NonVoid (Id -> PrimRep
    idPrimRep Id
    id', Id
    id'))

    -- | Assumes that arguments have one PrimRep, which holds after unarisation.
    -- See Note [Post-unarisation invariants]
    addArgReps :: [NonVoid StgArg] -> [NonVoid (PrimRep, StgArg)]
    addArgReps :: [NonVoid StgArg] -> [NonVoid (PrimRep, StgArg)]
    addArgReps = (NonVoid StgArg -> NonVoid (PrimRep, StgArg))
    -> [NonVoid StgArg] -> [NonVoid (PrimRep, StgArg)]
    forall a b. (a -> b) -> [a] -> [b]
    map (\NonVoid StgArg
    arg -> let arg' :: StgArg
    arg' = NonVoid StgArg -> StgArg
    forall a. NonVoid a -> a
    fromNonVoid NonVoid StgArg
    arg
                               in (PrimRep, StgArg) -> NonVoid (PrimRep, StgArg)
    forall a. a -> NonVoid a
    NonVoid (StgArg -> PrimRep
    argPrimRep StgArg
    arg', StgArg
    arg'))

    -- | Assumes that the argument has one PrimRep, which holds after unarisation.
    -- See Note [Post-unarisation invariants]
    argPrimRep :: StgArg -> PrimRep
    argPrimRep :: StgArg -> PrimRep
    argPrimRep StgArg
    arg = (() :: Constraint) => Type -> PrimRep
    Type -> PrimRep
    typePrimRep1 (StgArg -> Type
    stgArgType StgArg
    arg)

    ------------------------------------------------------
    --                Building LambdaFormInfo
    ------------------------------------------------------

    mkLFArgument :: Id -> LambdaFormInfo
    mkLFArgument :: Id -> LambdaFormInfo
    mkLFArgument Id
    id
      | (() :: Constraint) => Type -> Bool
    Type -> Bool
    isUnliftedType Type
    ty      = LambdaFormInfo
    LFUnlifted
      | Type -> Bool
    mightBeFunTy Type
    ty = Bool -> LambdaFormInfo
    LFUnknown Bool
    True
      | Bool
    otherwise              = Bool -> LambdaFormInfo
    LFUnknown Bool
    False
      where
        ty :: Type
    ty = Id -> Type
    idType Id
    id

    -------------
    mkLFLetNoEscape :: LambdaFormInfo
    mkLFLetNoEscape :: LambdaFormInfo
    mkLFLetNoEscape = LambdaFormInfo
    LFLetNoEscape

    -------------
    mkLFReEntrant :: TopLevelFlag    -- True of top level
                  -> [Id]            -- Free vars
                  -> [Id]            -- Args
                  -> ArgDescr        -- Argument descriptor
                  -> LambdaFormInfo

    mkLFReEntrant :: TopLevelFlag -> [Id] -> [Id] -> ArgDescr -> LambdaFormInfo
    mkLFReEntrant TopLevelFlag
    _ [Id]
    _ [] ArgDescr
    _
      = String -> SDoc -> LambdaFormInfo
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "mkLFReEntrant" SDoc
    forall doc. IsOutput doc => doc
    empty
    mkLFReEntrant TopLevelFlag
    top [Id]
    fvs [Id]
    args ArgDescr
    arg_descr
      = TopLevelFlag -> Int -> Bool -> ArgDescr -> LambdaFormInfo
    LFReEntrant TopLevelFlag
    top ([Id] -> Int
    forall a. [a] -> Int
    forall (t :: * -> *) a. Foldable t => t a -> Int
    length [Id]
    args) ([Id] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Id]
    fvs) ArgDescr
    arg_descr

    -------------
    mkLFThunk :: Type -> TopLevelFlag -> [Id] -> UpdateFlag -> LambdaFormInfo
    mkLFThunk :: Type -> TopLevelFlag -> [Id] -> UpdateFlag -> LambdaFormInfo
    mkLFThunk Type
    thunk_ty TopLevelFlag
    top [Id]
    fvs UpdateFlag
    upd_flag
      = Bool -> LambdaFormInfo -> LambdaFormInfo
    forall a. HasCallStack => Bool -> a -> a
    assert (Bool -> Bool
    not (UpdateFlag -> Bool
    isUpdatable UpdateFlag
    upd_flag) Bool -> Bool -> Bool
    || Bool -> Bool
    not ((() :: Constraint) => Type -> Bool
    Type -> Bool
    isUnliftedType Type
    thunk_ty)) (LambdaFormInfo -> LambdaFormInfo)
    -> LambdaFormInfo -> LambdaFormInfo
    forall a b. (a -> b) -> a -> b
    $
        TopLevelFlag
    -> Bool -> Bool -> StandardFormInfo -> Bool -> LambdaFormInfo
    LFThunk TopLevelFlag
    top ([Id] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Id]
    fvs)
                (UpdateFlag -> Bool
    isUpdatable UpdateFlag
    upd_flag)
                StandardFormInfo
    NonStandardThunk
                (Type -> Bool
    mightBeFunTy Type
    thunk_ty)

    -------------
    mkConLFInfo :: DataCon -> LambdaFormInfo
    mkConLFInfo :: DataCon -> LambdaFormInfo
    mkConLFInfo DataCon
    con = DataCon -> LambdaFormInfo
    LFCon DataCon
    con

    -------------
    mkSelectorLFInfo :: Id -> Int -> Bool -> LambdaFormInfo
    mkSelectorLFInfo :: Id -> Int -> Bool -> LambdaFormInfo
    mkSelectorLFInfo Id
    id Int
    offset Bool
    updatable
      = TopLevelFlag
    -> Bool -> Bool -> StandardFormInfo -> Bool -> LambdaFormInfo
    LFThunk TopLevelFlag
    NotTopLevel Bool
    False Bool
    updatable (Int -> StandardFormInfo
    SelectorThunk Int
    offset)
            (Type -> Bool
    mightBeFunTy (Id -> Type
    idType Id
    id))

    -------------
    mkApLFInfo :: Id -> UpdateFlag -> Arity -> LambdaFormInfo
    mkApLFInfo :: Id -> UpdateFlag -> Int -> LambdaFormInfo
    mkApLFInfo Id
    id UpdateFlag
    upd_flag Int
    arity
      = TopLevelFlag
    -> Bool -> Bool -> StandardFormInfo -> Bool -> LambdaFormInfo
    LFThunk TopLevelFlag
    NotTopLevel (Int
    arity Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0) (UpdateFlag -> Bool
    isUpdatable UpdateFlag
    upd_flag) (Int -> StandardFormInfo
    ApThunk Int
    arity)
            (Type -> Bool
    mightBeFunTy (Id -> Type
    idType Id
    id))

    -------------
    mkLFImported :: Id -> LambdaFormInfo
    mkLFImported :: Id -> LambdaFormInfo
    mkLFImported Id
    id =
        -- See Note [Conveying CAF-info and LFInfo between modules] in
        -- GHC.StgToCmm.Types
        case Id -> Maybe LambdaFormInfo
    idLFInfo_maybe Id
    id of
          Just LambdaFormInfo
    lf_info ->
            -- Use the LambdaFormInfo from the interface
            LambdaFormInfo
    lf_info
          Maybe LambdaFormInfo
    Nothing
            -- Interface doesn't have a LambdaFormInfo, so make a conservative one from the type.
            -- See Note [The LFInfo of Imported Ids]; The order of the guards musn't be changed!
            | Int
    arity Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    > Int
    0
            -> TopLevelFlag -> Int -> Bool -> ArgDescr -> LambdaFormInfo
    LFReEntrant TopLevelFlag
    TopLevel Int
    arity Bool
    True ArgDescr
    ArgUnknown

            | Just DataCon
    con <- Id -> Maybe DataCon
    isDataConId_maybe Id
    id
              -- See Note [Imported unlifted nullary datacon wrappers must have correct LFInfo] in GHC.StgToCmm.Types
              -- and Note [The LFInfo of Imported Ids] below
            -> Bool -> LambdaFormInfo -> LambdaFormInfo
    forall a. HasCallStack => Bool -> a -> a
    assert (DataCon -> Bool
    hasNoNonZeroWidthArgs DataCon
    con) (LambdaFormInfo -> LambdaFormInfo)
    -> LambdaFormInfo -> LambdaFormInfo
    forall a b. (a -> b) -> a -> b
    $
               DataCon -> LambdaFormInfo
    LFCon DataCon
    con   -- An imported nullary constructor
                           -- We assume that the constructor is evaluated so that
                           -- the id really does point directly to the constructor

            | Bool
    otherwise
            -> Id -> LambdaFormInfo
    mkLFArgument Id
    id -- Not sure of exact arity
      where
        arity :: Int
    arity = Id -> Int
    idFunRepArity Id
    id
        hasNoNonZeroWidthArgs :: DataCon -> Bool
    hasNoNonZeroWidthArgs = (Scaled Type -> Bool) -> [Scaled Type] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all ((() :: Constraint) => Type -> Bool
    Type -> Bool
    isZeroBitTy (Type -> Bool) -> (Scaled Type -> Type) -> Scaled Type -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Scaled Type -> Type
    forall a. Scaled a -> a
    scaledThing) ([Scaled Type] -> Bool)
    -> (DataCon -> [Scaled Type]) -> DataCon -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . DataCon -> [Scaled Type]
    dataConRepArgTys

    {-
    Note [The LFInfo of Imported Ids]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    As explained in Note [Conveying CAF-info and LFInfo between modules] and
    Note [Imported unlifted nullary datacon wrappers must have correct LFInfo], the
    LambdaFormInfo records the details of a closure representation and is often,
    when optimisations are enabled, serialized to the interface of a module.

    In particular, the `lfInfo` field of the `IdInfo` field of an `Id`
    * For Ids defined in this module: is `Nothing`
    * For imported Ids:
      * is (Just lf_info) if the LFInfo was serialised into the interface file
        (typically, when the exporting module was compiled with -O)
      * is Nothing if it wasn't serialised

    However, when an interface doesn't have a LambdaFormInfo for some imported Id
    (so that its `lfInfo` field is `Nothing`), we can conservatively create one
    using `mkLFImported`.

    The LambdaFormInfo we give an Id is used in determining how to tag its pointer
    (see `litIdInfo`). Therefore, it's crucial we re-construct a LambdaFormInfo as
    faithfully as possible or otherwise risk having pointers incorrectly tagged,
    which can lead to performance issues and even segmentation faults (see #23231
    and #23146). In particular, saturated data constructor applications *must* be
    unambiguously given `LFCon`, and the invariant

      If the LFInfo (serialised or built with mkLFImported) says LFCon, then it
      really is a static data constructor, and similar for LFReEntrant

    must be upheld.

    In `mkLFImported`, we make a conservative approximation to the real
    LambdaFormInfo as follows:

    (1) Ids with an `idFunRepArity > 0` are `LFReEntrant` and pointers to them are
    tagged (by `litIdInfo`) with the corresponding arity.
        - This is also true of data con wrappers and workers with arity > 0,
        regardless of the runtime relevance of the arguments
        - For example, `Just :: a -> Maybe a` is given `LFReEntrant`
                   and `HNil :: (a ~# '[]) -> HList a` is given `LFReEntrant` too

    (2) Data constructors with `idFunRepArity == 0` should be given `LFCon` because
    they are fully saturated data constructor applications and pointers to them
    should be tagged with the constructor index.

    (2.1) A datacon *wrapper* with zero arity must be a fully saturated application
    of the worker to zero-width arguments only (which are dropped after unarisation)

    (2.2) A datacon *worker* with zero arity is trivially fully saturated, it takes
    no arguments whatsoever (not even zero-width args)

    To ensure we properly give `LFReEntrant` to data constructors with some arity,
    and `LFCon` only to data constructors with zero arity, we must first check for
    `arity > 0` and only afterwards `isDataConId` -- the order of the guards in
    `mkLFImported` is quite important.

    As an example, consider the following data constructors:

      data T1 a where
        TCon1 :: {-# UNPACK #-} !(a :~: True) -> T1 a

      data T2 a where
        TCon2 :: {-# UNPACK #-} !() -> T2 a

      data T3 a where
        TCon3 :: T3 '[]

    `TCon1`'s wrapper has a lifted equality argument, which is non-zero-width, while
    the worker has an unlifted equality argument, which is zero-width.

    `TCon2`'s wrapper has a lifted equality argument, which is non-zero-width,
    while the worker has no arguments.

    `TCon3`'s wrapper has no arguments, and the worker has 1 zero-width argument;
    their Core representation:

      $WTCon3 :: T3 '[]
      $WTCon3 = TCon3 @[] <Refl>

      TCon3 :: forall (a :: * -> *). (a ~# []) => T a
      TCon3 = /\a. \(co :: a~#[]). TCon3 co

    For `TCon1`, both the wrapper and worker will be given `LFReEntrant` since they
    both have arity == 1.

    For `TCon2`, the wrapper will be given `LFReEntrant` since it has arity == 1
    while the worker is `LFCon` since its arity == 0

    For `TCon3`, the wrapper will be given `LFCon` since its arity == 0 and the
    worker `LFReEntrant` since its arity == 1

    One might think we could give *workers* with only zero-width-args the `LFCon`
    LambdaFormInfo, e.g. give `LFCon` to the worker of `TCon1` and `TCon3`.
    However, these workers, albeit rarely used, are unambiguously functions
    -- which makes `LFReEntrant`, the LambdaFormInfo we give them, correct.
    See also the discussion in #23158.

    -}

    -------------
    mkLFStringLit :: LambdaFormInfo
    mkLFStringLit :: LambdaFormInfo
    mkLFStringLit = LambdaFormInfo
    LFUnlifted

    -----------------------------------------------------
    --                Dynamic pointer tagging
    -----------------------------------------------------

    type DynTag = Int       -- The tag on a *pointer*
                            -- (from the dynamic-tagging paper)

    -- Note [Data constructor dynamic tags]
    -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    --
    -- The family size of a data type (the number of constructors
    -- or the arity of a function) can be either:
    --    * small, if the family size < 2**tag_bits
    --    * big, otherwise.
    --
    -- Small families can have the constructor tag in the tag bits.
    -- Big families always use the tag values 1..mAX_PTR_TAG to represent
    -- evaluatedness, the last one lumping together all overflowing ones.
    -- We don't have very many tag bits: for example, we have 2 bits on
    -- x86-32 and 3 bits on x86-64.
    --
    -- Also see Note [Tagging big families] in GHC.StgToCmm.Expr
    --
    -- The interpreter also needs to be updated if we change the
    -- tagging strategy; see tagConstr in rts/Interpreter.c.

    isSmallFamily :: Platform -> Int -> Bool
    isSmallFamily :: Platform -> Int -> Bool
    isSmallFamily Platform
    platform Int
    fam_size = Int
    fam_size Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    <= Platform -> Int
    mAX_PTR_TAG Platform
    platform

    tagForCon :: Platform -> DataCon -> DynTag
    tagForCon :: Platform -> DataCon -> Int
    tagForCon Platform
    platform DataCon
    con = Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min (DataCon -> Int
    dataConTag DataCon
    con) (Platform -> Int
    mAX_PTR_TAG Platform
    platform)
    -- NB: 1-indexed

    tagForArity :: Platform -> RepArity -> DynTag
    tagForArity :: Platform -> Int -> Int
    tagForArity Platform
    platform Int
    arity
     | Platform -> Int -> Bool
    isSmallFamily Platform
    platform Int
    arity = Int
    arity
     | Bool
    otherwise                    = Int
    0

    -- | Return the tag in the low order bits of a variable bound
    -- to this LambdaForm
    lfDynTag :: Platform -> LambdaFormInfo -> DynTag
    lfDynTag :: Platform -> LambdaFormInfo -> Int
    lfDynTag Platform
    platform LambdaFormInfo
    lf = case LambdaFormInfo
    lf of
       LFCon DataCon
    con               -> Platform -> DataCon -> Int
    tagForCon   Platform
    platform DataCon
    con
       LFReEntrant TopLevelFlag
    _ Int
    arity Bool
    _ ArgDescr
    _ -> Platform -> Int -> Int
    tagForArity Platform
    platform Int
    arity
       LambdaFormInfo
    _other                  -> Int
    0

    -----------------------------------------------------------------------------
    --                Observing LambdaFormInfo
    -----------------------------------------------------------------------------

    ------------
    isLFThunk :: LambdaFormInfo -> Bool
    isLFThunk :: LambdaFormInfo -> Bool
    isLFThunk (LFThunk {})  = Bool
    True
    isLFThunk LambdaFormInfo
    _ = Bool
    False

    isLFReEntrant :: LambdaFormInfo -> Bool
    isLFReEntrant :: LambdaFormInfo -> Bool
    isLFReEntrant (LFReEntrant {}) = Bool
    True
    isLFReEntrant LambdaFormInfo
    _                = Bool
    False

    -----------------------------------------------------------------------------
    --                Choosing SM reps
    -----------------------------------------------------------------------------

    lfClosureType :: LambdaFormInfo -> ClosureTypeInfo
    lfClosureType :: LambdaFormInfo -> ClosureTypeInfo
    lfClosureType (LFReEntrant TopLevelFlag
    _ Int
    arity Bool
    _ ArgDescr
    argd) = Int -> ArgDescr -> ClosureTypeInfo
    Fun Int
    arity ArgDescr
    argd
    lfClosureType (LFCon DataCon
    con)                  = Int -> ConstrDescription -> ClosureTypeInfo
    Constr (DataCon -> Int
    dataConTagZ DataCon
    con)
                                                        (DataCon -> ConstrDescription
    dataConIdentity DataCon
    con)
    lfClosureType (LFThunk TopLevelFlag
    _ Bool
    _ Bool
    _ StandardFormInfo
    is_sel Bool
    _)     = StandardFormInfo -> ClosureTypeInfo
    thunkClosureType StandardFormInfo
    is_sel
    lfClosureType LambdaFormInfo
    _                            = String -> ClosureTypeInfo
    forall a. HasCallStack => String -> a
    panic String
    "lfClosureType"

    thunkClosureType :: StandardFormInfo -> ClosureTypeInfo
    thunkClosureType :: StandardFormInfo -> ClosureTypeInfo
    thunkClosureType (SelectorThunk Int
    off) = Int -> ClosureTypeInfo
    ThunkSelector Int
    off
    thunkClosureType StandardFormInfo
    _                   = ClosureTypeInfo
    Thunk

    -- We *do* get non-updatable top-level thunks sometimes.  eg. f = g
    -- gets compiled to a jump to g (if g has non-zero arity), instead of
    -- messing around with update frames and PAPs.  We set the closure type
    -- to FUN_STATIC in this case.

    -----------------------------------------------------------------------------
    --                nodeMustPointToIt
    -----------------------------------------------------------------------------

    nodeMustPointToIt :: Profile -> LambdaFormInfo -> Bool
    -- If nodeMustPointToIt is true, then the entry convention for
    -- this closure has R1 (the "Node" register) pointing to the
    -- closure itself --- the "self" argument

    nodeMustPointToIt :: Profile -> LambdaFormInfo -> Bool
    nodeMustPointToIt Profile
    _ (LFReEntrant TopLevelFlag
    top Int
    _ Bool
    no_fvs ArgDescr
    _)
      =  Bool -> Bool
    not Bool
    no_fvs          -- Certainly if it has fvs we need to point to it
      Bool -> Bool -> Bool
    || TopLevelFlag -> Bool
    isNotTopLevel TopLevelFlag
    top   -- See Note [GC recovery]
            -- For lex_profiling we also access the cost centre for a
            -- non-inherited (i.e. non-top-level) function.
            -- The isNotTopLevel test above ensures this is ok.

    nodeMustPointToIt Profile
    profile (LFThunk TopLevelFlag
    top Bool
    no_fvs Bool
    updatable StandardFormInfo
    NonStandardThunk Bool
    _)
      =  Bool -> Bool
    not Bool
    no_fvs            -- Self parameter
      Bool -> Bool -> Bool
    || TopLevelFlag -> Bool
    isNotTopLevel TopLevelFlag
    top     -- Note [GC recovery]
      Bool -> Bool -> Bool
    || Bool
    updatable             -- Need to push update frame
      Bool -> Bool -> Bool
    || Profile -> Bool
    profileIsProfiling Profile
    profile
              -- For the non-updatable (single-entry case):
              --
              -- True if has fvs (in which case we need access to them, and we
              --                    should black-hole it)
              -- or profiling (in which case we need to recover the cost centre
              --                 from inside it)  ToDo: do we need this even for
              --                                    top-level thunks? If not,
              --                                    isNotTopLevel subsumes this

    nodeMustPointToIt Profile
    _ (LFThunk {})        -- Node must point to a standard-form thunk
      = Bool
    True

    nodeMustPointToIt Profile
    _ (LFCon DataCon
    _) = Bool
    True

            -- Strictly speaking, the above two don't need Node to point
            -- to it if the arity = 0.  But this is a *really* unlikely
            -- situation.  If we know it's nil (say) and we are entering
            -- it. Eg: let x = [] in x then we will certainly have inlined
            -- x, since nil is a simple atom.  So we gain little by not
            -- having Node point to known zero-arity things.  On the other
            -- hand, we do lose something; Patrick's code for figuring out
            -- when something has been updated but not entered relies on
            -- having Node point to the result of an update.  SLPJ
            -- 27/11/92.

    nodeMustPointToIt Profile
    _ (LFUnknown Bool
    _)   = Bool
    True
    nodeMustPointToIt Profile
    _ LambdaFormInfo
    LFUnlifted      = Bool
    False
    nodeMustPointToIt Profile
    _ LambdaFormInfo
    LFLetNoEscape   = Bool
    False

    {- Note [GC recovery]
    ~~~~~~~~~~~~~~~~~~~~~
    If we a have a local let-binding (function or thunk)
       let f = <body> in ...
    AND <body> allocates, then the heap-overflow check needs to know how
    to re-start the evaluation.  It uses the "self" pointer to do this.
    So even if there are no free variables in <body>, we still make
    nodeMustPointToIt be True for non-top-level bindings.

    Why do any such bindings exist?  After all, let-floating should have
    floated them out.  Well, a clever optimiser might leave one there to
    avoid a space leak, deliberately recomputing a thunk.  Also (and this
    really does happen occasionally) let-floating may make a function f smaller
    so it can be inlined, so now (f True) may generate a local no-fv closure.
    This actually happened during bootstrapping GHC itself, with f=mkRdrFunBind
    in GHC.Tc.Deriv.Generate.) -}

    -----------------------------------------------------------------------------
    --                getCallMethod
    -----------------------------------------------------------------------------

    {- The entry conventions depend on the type of closure being entered,
    whether or not it has free variables, and whether we're running
    sequentially or in parallel.

    Closure                           Node   Argument   Enter
    Characteristics              Par   Req'd  Passing    Via
    ---------------------------------------------------------------------------
    Unknown                     & no  & yes & stack     & node
    Known fun (>1 arg), no fvs  & no  & no  & registers & fast entry (enough args)
                                                        & slow entry (otherwise)
    Known fun (>1 arg), fvs     & no  & yes & registers & fast entry (enough args)
    0 arg, no fvs \r,\s         & no  & no  & n/a       & direct entry
    0 arg, no fvs \u            & no  & yes & n/a       & node
    0 arg, fvs \r,\s,selector   & no  & yes & n/a       & node
    0 arg, fvs \r,\s            & no  & yes & n/a       & direct entry
    0 arg, fvs \u               & no  & yes & n/a       & node
    Unknown                     & yes & yes & stack     & node
    Known fun (>1 arg), no fvs  & yes & no  & registers & fast entry (enough args)
                                                        & slow entry (otherwise)
    Known fun (>1 arg), fvs     & yes & yes & registers & node
    0 arg, fvs \r,\s,selector   & yes & yes & n/a       & node
    0 arg, no fvs \r,\s         & yes & no  & n/a       & direct entry
    0 arg, no fvs \u            & yes & yes & n/a       & node
    0 arg, fvs \r,\s            & yes & yes & n/a       & node
    0 arg, fvs \u               & yes & yes & n/a       & node

    When black-holing, single-entry closures could also be entered via node
    (rather than directly) to catch double-entry. -}

    data CallMethod
      = EnterIt             -- ^ No args, not a function

      | JumpToIt BlockId [LocalReg] -- A join point or a header of a local loop

      | ReturnIt            -- It's a value (function, unboxed value,
                            -- or constructor), so just return it.

      | InferedReturnIt     -- A properly tagged value, as determined by tag inference.
                            -- See Note [Tag Inference] and Note [Tag inference passes] in
                            -- GHC.Stg.InferTags.
                            -- It behaves /precisely/ like `ReturnIt`, except that when debugging is
                            -- enabled we emit an extra assertion to check that the returned value is
                            -- properly tagged.  We can use this as a check that tag inference is working
                            -- correctly.
                            -- TODO: SPJ suggested we could combine this with EnterIt, but for now I decided
                            -- not to do so.

      | SlowCall            -- Unknown fun, or known fun with
                            -- too few args.

      | DirectEntry         -- Jump directly, with args in regs
            CLabel          --   The code label
            RepArity        --   Its arity

    instance Outputable CallMethod where
      ppr :: CallMethod -> SDoc
    ppr (CallMethod
    EnterIt) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Enter"
      ppr (JumpToIt {}) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "JumpToIt"
      ppr (CallMethod
    ReturnIt ) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "ReturnIt"
      ppr (CallMethod
    InferedReturnIt) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "InferedReturnIt"
      ppr (CallMethod
    SlowCall ) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "SlowCall"
      ppr (DirectEntry {}) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "DirectEntry"

    getCallMethod :: StgToCmmConfig
                  -> Name           -- Function being applied
                  -> Id             -- Function Id used to chech if it can refer to
                                    -- CAF's and whether the function is tail-calling
                                    -- itself
                  -> LambdaFormInfo -- Its info
                  -> RepArity       -- Number of available arguments
                  -> RepArity       -- Number of them being void arguments
                  -> CgLoc          -- Passed in from cgIdApp so that we can
                                    -- handle let-no-escape bindings and self-recursive
                                    -- tail calls using the same data constructor,
                                    -- JumpToIt. This saves us one case branch in
                                    -- cgIdApp
                  -> Maybe SelfLoopInfo -- can we perform a self-recursive tail-call
                  -> CallMethod

    getCallMethod :: StgToCmmConfig
    -> Name
    -> Id
    -> LambdaFormInfo
    -> Int
    -> Int
    -> CgLoc
    -> Maybe SelfLoopInfo
    -> CallMethod
    getCallMethod StgToCmmConfig
    cfg Name
    _ Id
    id LambdaFormInfo
    _  Int
    n_args Int
    v_args CgLoc
    _cg_loc (Just (Id
    self_loop_id, BlockId
    block_id, [LocalReg]
    args))
      | StgToCmmConfig -> Bool
    stgToCmmLoopification StgToCmmConfig
    cfg
      , Id
    id Id -> Id -> Bool
    forall a. Eq a => a -> a -> Bool
    == Id
    self_loop_id
      , [LocalReg]
    args [LocalReg] -> Int -> Bool
    forall a. [a] -> Int -> Bool
    `lengthIs` (Int
    n_args Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    v_args)
      -- If these patterns match then we know that:
      --   * loopification optimisation is turned on
      --   * function is performing a self-recursive call in a tail position
      --   * number of non-void parameters of the function matches functions arity.
      -- See Note [Self-recursive tail calls] and Note [Void arguments in
      -- self-recursive tail calls] in GHC.StgToCmm.Expr for more details
      = BlockId -> [LocalReg] -> CallMethod
    JumpToIt BlockId
    block_id [LocalReg]
    args

    getCallMethod StgToCmmConfig
    cfg Name
    name Id
    id (LFReEntrant TopLevelFlag
    _ Int
    arity Bool
    _ ArgDescr
    _) Int
    n_args Int
    _v_args CgLoc
    _cg_loc Maybe SelfLoopInfo
    _self_loop_info
      | Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0 -- No args at all
      Bool -> Bool -> Bool
    && Bool -> Bool
    not (Profile -> Bool
    profileIsProfiling (StgToCmmConfig -> Profile
    stgToCmmProfile StgToCmmConfig
    cfg))
         -- See Note [Evaluating functions with profiling] in rts/Apply.cmm
      = Bool -> CallMethod -> CallMethod
    forall a. HasCallStack => Bool -> a -> a
    assert (Int
    arity Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Int
    0) CallMethod
    ReturnIt
      | Int
    n_args Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    arity = CallMethod
    SlowCall        -- Not enough args
      | Bool
    otherwise      = CLabel -> Int -> CallMethod
    DirectEntry (Platform -> Name -> CafInfo -> CLabel
    enterIdLabel (StgToCmmConfig -> Platform
    stgToCmmPlatform StgToCmmConfig
    cfg) Name
    name (Id -> CafInfo
    idCafInfo Id
    id)) Int
    arity

    getCallMethod StgToCmmConfig
    _ Name
    _name Id
    _ LambdaFormInfo
    LFUnlifted Int
    n_args Int
    _v_args CgLoc
    _cg_loc Maybe SelfLoopInfo
    _self_loop_info
      = Bool -> CallMethod -> CallMethod
    forall a. HasCallStack => Bool -> a -> a
    assert (Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0) CallMethod
    ReturnIt

    getCallMethod StgToCmmConfig
    _ Name
    _name Id
    _ (LFCon DataCon
    _) Int
    n_args Int
    _v_args CgLoc
    _cg_loc Maybe SelfLoopInfo
    _self_loop_info
      = Bool -> CallMethod -> CallMethod
    forall a. HasCallStack => Bool -> a -> a
    assert (Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0) CallMethod
    ReturnIt
        -- n_args=0 because it'd be ill-typed to apply a saturated
        --          constructor application to anything

    getCallMethod StgToCmmConfig
    cfg Name
    name Id
    id (LFThunk TopLevelFlag
    _ Bool
    _ Bool
    updatable StandardFormInfo
    std_form_info Bool
    is_fun)
                  Int
    n_args Int
    _v_args CgLoc
    _cg_loc Maybe SelfLoopInfo
    _self_loop_info

      | Just TagSig
    sig <- Id -> Maybe TagSig
    idTagSig_maybe Id
    id
      , TagSig -> Bool
    isTaggedSig TagSig
    sig -- Infered to be already evaluated by Tag Inference
      , Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0     -- See Note [Tag Inference]
      = CallMethod
    InferedReturnIt

      | Bool
    is_fun      -- it *might* be a function, so we must "call" it (which is always safe)
      = CallMethod
    SlowCall    -- We cannot just enter it [in eval/apply, the entry code
                    -- is the fast-entry code]

      -- Since is_fun is False, we are *definitely* looking at a data value
      | Bool
    updatable Bool -> Bool -> Bool
    || StgToCmmConfig -> Bool
    stgToCmmDoTicky StgToCmmConfig
    cfg -- to catch double entry
          {- OLD: || opt_SMP
             I decided to remove this, because in SMP mode it doesn't matter
             if we enter the same thunk multiple times, so the optimisation
             of jumping directly to the entry code is still valid.  --SDM
            -}
      = CallMethod
    EnterIt

      -- even a non-updatable selector thunk can be updated by the garbage
      -- collector, so we must enter it. (#8817)
      | SelectorThunk{} <- StandardFormInfo
    std_form_info
      = CallMethod
    EnterIt

        -- We used to have assert (n_args == 0 ), but actually it is
        -- possible for the optimiser to generate
        --   let bot :: Int = error Int "urk"
        --   in (bot `cast` unsafeCoerce Int (Int -> Int)) 3
        -- This happens as a result of the case-of-error transformation
        -- So the right thing to do is just to enter the thing

      | Bool
    otherwise        -- Jump direct to code for single-entry thunks
      = Bool -> CallMethod -> CallMethod
    forall a. HasCallStack => Bool -> a -> a
    assert (Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0) (CallMethod -> CallMethod) -> CallMethod -> CallMethod
    forall a b. (a -> b) -> a -> b
    $
        CLabel -> Int -> CallMethod
    DirectEntry (Platform -> Name -> CafInfo -> StandardFormInfo -> Bool -> CLabel
    thunkEntryLabel (StgToCmmConfig -> Platform
    stgToCmmPlatform StgToCmmConfig
    cfg) Name
    name (Id -> CafInfo
    idCafInfo Id
    id) StandardFormInfo
    std_form_info
                    Bool
    updatable) Int
    0

    -- Imported(Unknown) Ids
    getCallMethod StgToCmmConfig
    cfg Name
    name Id
    id (LFUnknown Bool
    might_be_a_function) Int
    n_args Int
    _v_args CgLoc
    _cg_locs Maybe SelfLoopInfo
    _self_loop_info
      | Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0
      , Just TagSig
    sig <- Id -> Maybe TagSig
    idTagSig_maybe Id
    id
      , TagSig -> Bool
    isTaggedSig TagSig
    sig -- Infered to be already evaluated by Tag Inference
      -- When profiling we must enter all potential functions to make sure we update the SCC
      -- even if the function itself is already evaluated.
      -- See Note [Evaluating functions with profiling] in rts/Apply.cmm
      , Bool -> Bool
    not (Profile -> Bool
    profileIsProfiling (StgToCmmConfig -> Profile
    stgToCmmProfile StgToCmmConfig
    cfg) Bool -> Bool -> Bool
    && Bool
    might_be_a_function)
      = CallMethod
    InferedReturnIt -- See Note [Tag Inference]

      | Bool
    might_be_a_function = CallMethod
    SlowCall

      | Bool
    otherwise =
          Bool -> SDoc -> CallMethod -> CallMethod
    forall a. HasCallStack => Bool -> SDoc -> a -> a
    assertPpr ( Int
    n_args Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    0) ( Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Int -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Int
    n_args )
          CallMethod
    EnterIt   -- Not a function

    -- TODO: Redundant with above match?
    -- getCallMethod _ name _ (LFUnknown False) n_args _v_args _cg_loc _self_loop_info
    --   = assertPpr (n_args == 0) (ppr name <+> ppr n_args)
    --     EnterIt -- Not a function

    getCallMethod StgToCmmConfig
    _ Name
    _name Id
    _ LambdaFormInfo
    LFLetNoEscape Int
    _n_args Int
    _v_args (LneLoc BlockId
    blk_id [LocalReg]
    lne_regs) Maybe SelfLoopInfo
    _self_loop_info
      = BlockId -> [LocalReg] -> CallMethod
    JumpToIt BlockId
    blk_id [LocalReg]
    lne_regs

    getCallMethod StgToCmmConfig
    _ Name
    _ Id
    _ LambdaFormInfo
    _ Int
    _ Int
    _ CgLoc
    _ Maybe SelfLoopInfo
    _ = String -> CallMethod
    forall a. HasCallStack => String -> a
    panic String
    "Unknown call method"

    -----------------------------------------------------------------------------
    --              Data types for closure information
    -----------------------------------------------------------------------------

    {- ClosureInfo: information about a binding

       We make a ClosureInfo for each let binding (both top level and not),
       but not bindings for data constructors: for those we build a CmmInfoTable
       directly (see mkDataConInfoTable).

       To a first approximation:
           ClosureInfo = (LambdaFormInfo, CmmInfoTable)

       A ClosureInfo has enough information
         a) to construct the info table itself, and build other things
            related to the binding (e.g. slow entry points for a function)
         b) to allocate a closure containing that info pointer (i.e.
               it knows the info table label)
    -}

    data ClosureInfo
      = ClosureInfo {
            ClosureInfo -> Id
    closureName :: !Id,           -- The thing bound to this closure
               -- we don't really need this field: it's only used in generating
               -- code for ticky and profiling, and we could pass the information
               -- around separately, but it doesn't do much harm to keep it here.

            ClosureInfo -> LambdaFormInfo
    closureLFInfo :: !LambdaFormInfo, -- NOTE: not an LFCon
              -- this tells us about what the closure contains: it's right-hand-side.

              -- the rest is just an unpacked CmmInfoTable.
            ClosureInfo -> CLabel
    closureInfoLabel :: !CLabel,
            ClosureInfo -> SMRep
    closureSMRep     :: !SMRep,          -- representation used by storage mgr
            ClosureInfo -> ProfilingInfo
    closureProf      :: !ProfilingInfo
        }

    -- | Convert from 'ClosureInfo' to 'CmmInfoTable'.
    mkCmmInfo :: ClosureInfo -> Id -> CostCentreStack -> CmmInfoTable
    mkCmmInfo :: ClosureInfo -> Id -> CostCentreStack -> CmmInfoTable
    mkCmmInfo ClosureInfo {Id
    CLabel
    SMRep
    LambdaFormInfo
    ProfilingInfo
    closureLFInfo :: ClosureInfo -> LambdaFormInfo
    closureName :: ClosureInfo -> Id
    closureInfoLabel :: ClosureInfo -> CLabel
    closureSMRep :: ClosureInfo -> SMRep
    closureProf :: ClosureInfo -> ProfilingInfo
    closureName :: Id
    closureLFInfo :: LambdaFormInfo
    closureInfoLabel :: CLabel
    closureSMRep :: SMRep
    closureProf :: ProfilingInfo
    ..} Id
    id CostCentreStack
    ccs
      = CmmInfoTable { cit_lbl :: CLabel
    cit_lbl  = CLabel
    closureInfoLabel
                     , cit_rep :: SMRep
    cit_rep  = SMRep
    closureSMRep
                     , cit_prof :: ProfilingInfo
    cit_prof = ProfilingInfo
    closureProf
                     , cit_srt :: Maybe CLabel
    cit_srt  = Maybe CLabel
    forall a. Maybe a
    Nothing
                     , cit_clo :: Maybe (Id, CostCentreStack)
    cit_clo  = if SMRep -> Bool
    isStaticRep SMRep
    closureSMRep
                                    then (Id, CostCentreStack) -> Maybe (Id, CostCentreStack)
    forall a. a -> Maybe a
    Just (Id
    id,CostCentreStack
    ccs)
                                    else Maybe (Id, CostCentreStack)
    forall a. Maybe a
    Nothing }

    --------------------------------------
    --        Building ClosureInfos
    --------------------------------------

    mkClosureInfo :: Profile
                  -> Bool                -- Is static
                  -> Id
                  -> LambdaFormInfo
                  -> Int -> Int        -- Total and pointer words
                  -> String         -- String descriptor
                  -> ClosureInfo
    mkClosureInfo :: Profile
    -> Bool
    -> Id
    -> LambdaFormInfo
    -> Int
    -> Int
    -> String
    -> ClosureInfo
    mkClosureInfo Profile
    profile Bool
    is_static Id
    id LambdaFormInfo
    lf_info Int
    tot_wds Int
    ptr_wds String
    val_descr
      = ClosureInfo { closureName :: Id
    closureName      = Id
    id
                    , closureLFInfo :: LambdaFormInfo
    closureLFInfo    = LambdaFormInfo
    lf_info
                    , closureInfoLabel :: CLabel
    closureInfoLabel = CLabel
    info_lbl   -- These three fields are
                    , closureSMRep :: SMRep
    closureSMRep     = SMRep
    sm_rep     -- (almost) an info table
                    , closureProf :: ProfilingInfo
    closureProf      = ProfilingInfo
    prof }     -- (we don't have an SRT yet)
      where
        sm_rep :: SMRep
    sm_rep     = Profile -> Bool -> Int -> Int -> ClosureTypeInfo -> SMRep
    mkHeapRep Profile
    profile Bool
    is_static Int
    ptr_wds Int
    nonptr_wds (LambdaFormInfo -> ClosureTypeInfo
    lfClosureType LambdaFormInfo
    lf_info)
        prof :: ProfilingInfo
    prof       = Profile -> Id -> String -> ProfilingInfo
    mkProfilingInfo Profile
    profile Id
    id String
    val_descr
        nonptr_wds :: Int
    nonptr_wds = Int
    tot_wds Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    ptr_wds

        info_lbl :: CLabel
    info_lbl = Platform -> Id -> LambdaFormInfo -> CLabel
    mkClosureInfoTableLabel (Profile -> Platform
    profilePlatform Profile
    profile) Id
    id LambdaFormInfo
    lf_info

    --------------------------------------
    --   Other functions over ClosureInfo
    --------------------------------------

    -- Eager blackholing is normally disabled, but can be turned on with
    -- -feager-blackholing.  When it is on, we replace the info pointer of
    -- the thunk with stg_EAGER_BLACKHOLE_info on entry.

    -- If we wanted to do eager blackholing with slop filling,
    -- we'd need to do it at the *end* of a basic block, otherwise
    -- we overwrite the free variables in the thunk that we still
    -- need.  We have a patch for this from Andy Cheadle, but not
    -- incorporated yet. --SDM [6/2004]
    --
    -- Previously, eager blackholing was enabled when ticky-ticky
    -- was on. But it didn't work, and it wasn't strictly necessary
    -- to bring back minimal ticky-ticky, so now EAGER_BLACKHOLING
    -- is unconditionally disabled. -- krc 1/2007
    --
    -- Static closures are never themselves black-holed.

    blackHoleOnEntry :: ClosureInfo -> Bool
    blackHoleOnEntry :: ClosureInfo -> Bool
    blackHoleOnEntry ClosureInfo
    cl_info
      | SMRep -> Bool
    isStaticRep (ClosureInfo -> SMRep
    closureSMRep ClosureInfo
    cl_info)
      = Bool
    False        -- Never black-hole a static closure

      | Bool
    otherwise
      = case ClosureInfo -> LambdaFormInfo
    closureLFInfo ClosureInfo
    cl_info of
          LFReEntrant {}            -> Bool
    False
          LambdaFormInfo
    LFLetNoEscape             -> Bool
    False
          LFThunk TopLevelFlag
    _ Bool
    _no_fvs Bool
    upd StandardFormInfo
    _ Bool
    _ -> Bool
    upd   -- See Note [Black-holing non-updatable thunks]
          LambdaFormInfo
    _other -> String -> Bool
    forall a. HasCallStack => String -> a
    panic String
    "blackHoleOnEntry"

    {- Note [Black-holing non-updatable thunks]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    We must not black-hole non-updatable (single-entry) thunks otherwise
    we run into issues like #10414. Specifically:

      * There is no reason to black-hole a non-updatable thunk: it should
        not be competed for by multiple threads

      * It could, conceivably, cause a space leak if we don't black-hole
        it, if there was a live but never-followed pointer pointing to it.
        Let's hope that doesn't happen.

      * It is dangerous to black-hole a non-updatable thunk because
         - is not updated (of course)
         - hence, if it is black-holed and another thread tries to evaluate
           it, that thread will block forever
        This actually happened in #10414.  So we do not black-hole
        non-updatable thunks.

      * How could two threads evaluate the same non-updatable (single-entry)
        thunk?  See Reid Barton's example below.

      * Only eager blackholing could possibly black-hole a non-updatable
        thunk, because lazy black-holing only affects thunks with an
        update frame on the stack.

    Here is and example due to Reid Barton (#10414):
        x = \u []  concat [[1], []]
    with the following definitions,

        concat x = case x of
            []       -> []
            (:) x xs -> (++) x (concat xs)

        (++) xs ys = case xs of
            []         -> ys
            (:) x rest -> (:) x ((++) rest ys)

    Where we use the syntax @\u []@ to denote an updatable thunk and @\s []@ to
    denote a single-entry (i.e. non-updatable) thunk. After a thread evaluates @x@
    to WHNF and calls @(++)@ the heap will contain the following thunks,

        x = 1 : y
        y = \u []  (++) [] z
        z = \s []  concat []

    Now that the stage is set, consider the follow evaluations by two racing threads
    A and B,

      1. Both threads enter @y@ before either is able to replace it with an
         indirection

      2. Thread A does the case analysis in @(++)@ and consequently enters @z@,
         replacing it with a black-hole

      3. At some later point thread B does the same case analysis and also attempts
         to enter @z@. However, it finds that it has been replaced with a black-hole
         so it blocks.

      4. Thread A eventually finishes evaluating @z@ (to @[]@) and updates @y@
         accordingly. It does *not* update @z@, however, as it is single-entry. This
         leaves Thread B blocked forever on a black-hole which will never be
         updated.

    To avoid this sort of condition we never black-hole non-updatable thunks.
    -}

    isStaticClosure :: ClosureInfo -> Bool
    isStaticClosure :: ClosureInfo -> Bool
    isStaticClosure ClosureInfo
    cl_info = SMRep -> Bool
    isStaticRep (ClosureInfo -> SMRep
    closureSMRep ClosureInfo
    cl_info)

    closureUpdReqd :: ClosureInfo -> Bool
    closureUpdReqd :: ClosureInfo -> Bool
    closureUpdReqd ClosureInfo{ closureLFInfo :: ClosureInfo -> LambdaFormInfo
    closureLFInfo = LambdaFormInfo
    lf_info } = LambdaFormInfo -> Bool
    lfUpdatable LambdaFormInfo
    lf_info

    lfUpdatable :: LambdaFormInfo -> Bool
    lfUpdatable :: LambdaFormInfo -> Bool
    lfUpdatable (LFThunk TopLevelFlag
    _ Bool
    _ Bool
    upd StandardFormInfo
    _ Bool
    _)  = Bool
    upd
    lfUpdatable LambdaFormInfo
    _ = Bool
    False

    closureReEntrant :: ClosureInfo -> Bool
    closureReEntrant :: ClosureInfo -> Bool
    closureReEntrant (ClosureInfo { closureLFInfo :: ClosureInfo -> LambdaFormInfo
    closureLFInfo = LFReEntrant {} }) = Bool
    True
    closureReEntrant ClosureInfo
    _ = Bool
    False

    closureFunInfo :: ClosureInfo -> Maybe (RepArity, ArgDescr)
    closureFunInfo :: ClosureInfo -> Maybe (Int, ArgDescr)
    closureFunInfo (ClosureInfo { closureLFInfo :: ClosureInfo -> LambdaFormInfo
    closureLFInfo = LambdaFormInfo
    lf_info }) = LambdaFormInfo -> Maybe (Int, ArgDescr)
    lfFunInfo LambdaFormInfo
    lf_info

    lfFunInfo :: LambdaFormInfo ->  Maybe (RepArity, ArgDescr)
    lfFunInfo :: LambdaFormInfo -> Maybe (Int, ArgDescr)
    lfFunInfo (LFReEntrant TopLevelFlag
    _ Int
    arity Bool
    _ ArgDescr
    arg_desc)  = (Int, ArgDescr) -> Maybe (Int, ArgDescr)
    forall a. a -> Maybe a
    Just (Int
    arity, ArgDescr
    arg_desc)
    lfFunInfo LambdaFormInfo
    _                                 = Maybe (Int, ArgDescr)
    forall a. Maybe a
    Nothing

    funTag :: Platform -> ClosureInfo -> DynTag
    funTag :: Platform -> ClosureInfo -> Int
    funTag Platform
    platform (ClosureInfo { closureLFInfo :: ClosureInfo -> LambdaFormInfo
    closureLFInfo = LambdaFormInfo
    lf_info })
        = Platform -> LambdaFormInfo -> Int
    lfDynTag Platform
    platform LambdaFormInfo
    lf_info

    isToplevClosure :: ClosureInfo -> Bool
    isToplevClosure :: ClosureInfo -> Bool
    isToplevClosure (ClosureInfo { closureLFInfo :: ClosureInfo -> LambdaFormInfo
    closureLFInfo = LambdaFormInfo
    lf_info })
      = case LambdaFormInfo
    lf_info of
          LFReEntrant TopLevelFlag
    TopLevel Int
    _ Bool
    _ ArgDescr
    _ -> Bool
    True
          LFThunk TopLevelFlag
    TopLevel Bool
    _ Bool
    _ StandardFormInfo
    _ Bool
    _   -> Bool
    True
          LambdaFormInfo
    _other                     -> Bool
    False

    --------------------------------------
    --   Label generation
    --------------------------------------

    staticClosureLabel :: Platform -> ClosureInfo -> CLabel
    staticClosureLabel :: Platform -> ClosureInfo -> CLabel
    staticClosureLabel Platform
    platform = Platform -> CLabel -> CLabel
    toClosureLbl Platform
    platform (CLabel -> CLabel)
    -> (ClosureInfo -> CLabel) -> ClosureInfo -> CLabel
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    .  ClosureInfo -> CLabel
    closureInfoLabel

    closureSlowEntryLabel :: Platform -> ClosureInfo -> CLabel
    closureSlowEntryLabel :: Platform -> ClosureInfo -> CLabel
    closureSlowEntryLabel Platform
    platform = Platform -> CLabel -> CLabel
    toSlowEntryLbl Platform
    platform (CLabel -> CLabel)
    -> (ClosureInfo -> CLabel) -> ClosureInfo -> CLabel
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ClosureInfo -> CLabel
    closureInfoLabel

    closureLocalEntryLabel :: Platform -> ClosureInfo -> CLabel
    closureLocalEntryLabel :: Platform -> ClosureInfo -> CLabel
    closureLocalEntryLabel Platform
    platform
      | Platform -> Bool
    platformTablesNextToCode Platform
    platform = Platform -> CLabel -> CLabel
    toInfoLbl  Platform
    platform (CLabel -> CLabel)
    -> (ClosureInfo -> CLabel) -> ClosureInfo -> CLabel
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ClosureInfo -> CLabel
    closureInfoLabel
      | Bool
    otherwise                         = Platform -> CLabel -> CLabel
    toEntryLbl Platform
    platform (CLabel -> CLabel)
    -> (ClosureInfo -> CLabel) -> ClosureInfo -> CLabel
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ClosureInfo -> CLabel
    closureInfoLabel

    -- | Get the info table label for a *thunk*.
    mkClosureInfoTableLabel :: Platform -> Id -> LambdaFormInfo -> CLabel
    mkClosureInfoTableLabel :: Platform -> Id -> LambdaFormInfo -> CLabel
    mkClosureInfoTableLabel Platform
    platform Id
    id LambdaFormInfo
    lf_info
      = case LambdaFormInfo
    lf_info of
            LFThunk TopLevelFlag
    _ Bool
    _ Bool
    upd_flag (SelectorThunk Int
    offset) Bool
    _
                          -> Platform -> Bool -> Int -> CLabel
    mkSelectorInfoLabel Platform
    platform Bool
    upd_flag Int
    offset

            LFThunk TopLevelFlag
    _ Bool
    _ Bool
    upd_flag (ApThunk Int
    arity) Bool
    _
                          -> Platform -> Bool -> Int -> CLabel
    mkApInfoTableLabel Platform
    platform Bool
    upd_flag Int
    arity

            LFThunk{}     -> Name -> CafInfo -> CLabel
    mkInfoTableLabel Name
    name CafInfo
    cafs
            LFReEntrant{} -> Name -> CafInfo -> CLabel
    mkInfoTableLabel Name
    name CafInfo
    cafs
            LambdaFormInfo
    _other        -> String -> CLabel
    forall a. HasCallStack => String -> a
    panic String
    "closureInfoTableLabel"

      where
        name :: Name
    name = Id -> Name
    idName Id
    id

        cafs :: CafInfo
    cafs     = Id -> CafInfo
    idCafInfo Id
    id

    -- | thunkEntryLabel is a local help function, not exported.  It's used from
    -- getCallMethod.
    thunkEntryLabel :: Platform -> Name -> CafInfo -> StandardFormInfo -> Bool -> CLabel
    thunkEntryLabel :: Platform -> Name -> CafInfo -> StandardFormInfo -> Bool -> CLabel
    thunkEntryLabel Platform
    platform Name
    thunk_id CafInfo
    caf_info StandardFormInfo
    sfi Bool
    upd_flag = case StandardFormInfo
    sfi of
       ApThunk Int
    arity        -> Platform -> Bool -> Int -> CLabel
    enterApLabel       Platform
    platform Bool
    upd_flag Int
    arity
       SelectorThunk Int
    offset -> Platform -> Bool -> Int -> CLabel
    enterSelectorLabel Platform
    platform Bool
    upd_flag Int
    offset
       StandardFormInfo
    _                    -> Platform -> Name -> CafInfo -> CLabel
    enterIdLabel       Platform
    platform Name
    thunk_id CafInfo
    caf_info

    enterApLabel :: Platform -> Bool -> Arity -> CLabel
    enterApLabel :: Platform -> Bool -> Int -> CLabel
    enterApLabel Platform
    platform Bool
    is_updatable Int
    arity
      | Platform -> Bool
    platformTablesNextToCode Platform
    platform = Platform -> Bool -> Int -> CLabel
    mkApInfoTableLabel Platform
    platform Bool
    is_updatable Int
    arity
      | Bool
    otherwise                         = Platform -> Bool -> Int -> CLabel
    mkApEntryLabel     Platform
    platform Bool
    is_updatable Int
    arity

    enterSelectorLabel :: Platform -> Bool -> WordOff -> CLabel
    enterSelectorLabel :: Platform -> Bool -> Int -> CLabel
    enterSelectorLabel Platform
    platform Bool
    upd_flag Int
    offset
      | Platform -> Bool
    platformTablesNextToCode Platform
    platform = Platform -> Bool -> Int -> CLabel
    mkSelectorInfoLabel  Platform
    platform Bool
    upd_flag Int
    offset
      | Bool
    otherwise                         = Platform -> Bool -> Int -> CLabel
    mkSelectorEntryLabel Platform
    platform Bool
    upd_flag Int
    offset

    enterIdLabel :: Platform -> Name -> CafInfo -> CLabel
    enterIdLabel :: Platform -> Name -> CafInfo -> CLabel
    enterIdLabel Platform
    platform Name
    id CafInfo
    c
      | Platform -> Bool
    platformTablesNextToCode Platform
    platform = Name -> CafInfo -> CLabel
    mkInfoTableLabel Name
    id CafInfo
    c
      | Bool
    otherwise                         = Name -> CafInfo -> CLabel
    mkEntryLabel Name
    id CafInfo
    c

    --------------------------------------
    --   Profiling
    --------------------------------------

    -- Profiling requires two pieces of information to be determined for
    -- each closure's info table --- description and type.

    -- The description is stored directly in the @CClosureInfoTable@ when the
    -- info table is built.

    -- The type is determined from the type information stored with the @Id@
    -- in the closure info using @closureTypeDescr@.

    mkProfilingInfo :: Profile -> Id -> String -> ProfilingInfo
    mkProfilingInfo :: Profile -> Id -> String -> ProfilingInfo
    mkProfilingInfo Profile
    profile Id
    id String
    val_descr
      | Bool -> Bool
    not (Profile -> Bool
    profileIsProfiling Profile
    profile) = ProfilingInfo
    NoProfilingInfo
      | Bool
    otherwise                        = ConstrDescription -> ConstrDescription -> ProfilingInfo
    ProfilingInfo ConstrDescription
    ty_descr_w8 (String -> ConstrDescription
    BS8.pack String
    val_descr)
      where
        ty_descr_w8 :: ConstrDescription
    ty_descr_w8  = String -> ConstrDescription
    BS8.pack (Type -> String
    getTyDescription (Id -> Type
    idType Id
    id))

    getTyDescription :: Type -> String
    getTyDescription :: Type -> String
    getTyDescription Type
    ty
      = case (Type -> ([Id], ThetaType, Type)
    tcSplitSigmaTy Type
    ty) of { ([Id]
    _, ThetaType
    _, Type
    tau_ty) ->
        case Type
    tau_ty of
          TyVarTy Id
    _              -> String
    "*"
          AppTy Type
    fun Type
    _            -> Type -> String
    getTyDescription Type
    fun
          TyConApp TyCon
    tycon ThetaType
    _       -> TyCon -> String
    forall a. NamedThing a => a -> String
    getOccString TyCon
    tycon
          FunTy {}              -> Char
    '-' Char -> ShowS
    forall a. a -> [a] -> [a]
    : Type -> String
    fun_result Type
    tau_ty
          ForAllTy ForAllTyBinder
    _  Type
    ty         -> Type -> String
    getTyDescription Type
    ty
          LitTy TyLit
    n                -> TyLit -> String
    getTyLitDescription TyLit
    n
          CastTy Type
    ty Coercion
    _            -> Type -> String
    getTyDescription Type
    ty
          CoercionTy Coercion
    co          -> String -> SDoc -> String
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "getTyDescription" (Coercion -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Coercion
    co)
        }
      where
        fun_result :: Type -> String
    fun_result (FunTy { ft_res :: Type -> Type
    ft_res = Type
    res }) = Char
    '>' Char -> ShowS
    forall a. a -> [a] -> [a]
    : Type -> String
    fun_result Type
    res
        fun_result Type
    other                    = Type -> String
    getTyDescription Type
    other

    getTyLitDescription :: TyLit -> String
    getTyLitDescription :: TyLit -> String
    getTyLitDescription TyLit
    l =
      case TyLit
    l of
        NumTyLit Integer
    n -> Integer -> String
    forall a. Show a => a -> String
    show Integer
    n
        StrTyLit FastString
    n -> FastString -> String
    forall a. Show a => a -> String
    show FastString
    n
        CharTyLit Char
    n -> Char -> String
    forall a. Show a => a -> String
    show Char
    n

    --------------------------------------
    --   CmmInfoTable-related things
    --------------------------------------

    mkDataConInfoTable :: Profile -> DataCon -> ConInfoTableLocation -> Bool -> Int -> Int -> CmmInfoTable
    mkDataConInfoTable :: Profile
    -> DataCon
    -> ConInfoTableLocation
    -> Bool
    -> Int
    -> Int
    -> CmmInfoTable
    mkDataConInfoTable Profile
    profile DataCon
    data_con ConInfoTableLocation
    mn Bool
    is_static Int
    ptr_wds Int
    nonptr_wds
     = CmmInfoTable { cit_lbl :: CLabel
    cit_lbl  = CLabel
    info_lbl
                    , cit_rep :: SMRep
    cit_rep  = SMRep
    sm_rep
                    , cit_prof :: ProfilingInfo
    cit_prof = ProfilingInfo
    prof
                    , cit_srt :: Maybe CLabel
    cit_srt  = Maybe CLabel
    forall a. Maybe a
    Nothing
                    , cit_clo :: Maybe (Id, CostCentreStack)
    cit_clo  = Maybe (Id, CostCentreStack)
    forall a. Maybe a
    Nothing }
     where
       name :: Name
    name = DataCon -> Name
    dataConName DataCon
    data_con
       info_lbl :: CLabel
    info_lbl = Name -> ConInfoTableLocation -> CLabel
    mkConInfoTableLabel Name
    name ConInfoTableLocation
    mn -- NoCAFRefs
       sm_rep :: SMRep
    sm_rep = Profile -> Bool -> Int -> Int -> ClosureTypeInfo -> SMRep
    mkHeapRep Profile
    profile Bool
    is_static Int
    ptr_wds Int
    nonptr_wds ClosureTypeInfo
    cl_type
       cl_type :: ClosureTypeInfo
    cl_type = Int -> ConstrDescription -> ClosureTypeInfo
    Constr (DataCon -> Int
    dataConTagZ DataCon
    data_con) (DataCon -> ConstrDescription
    dataConIdentity DataCon
    data_con)
                      -- We keep the *zero-indexed* tag in the srt_len field
                      -- of the info table of a data constructor.

       prof :: ProfilingInfo
    prof | Bool -> Bool
    not (Profile -> Bool
    profileIsProfiling Profile
    profile) = ProfilingInfo
    NoProfilingInfo
            | Bool
    otherwise                        = ConstrDescription -> ConstrDescription -> ProfilingInfo
    ProfilingInfo ConstrDescription
    ty_descr ConstrDescription
    val_descr

       ty_descr :: ConstrDescription
    ty_descr  = String -> ConstrDescription
    BS8.pack (String -> ConstrDescription) -> String -> ConstrDescription
    forall a b. (a -> b) -> a -> b
    $ OccName -> String
    occNameString (OccName -> String) -> OccName -> String
    forall a b. (a -> b) -> a -> b
    $ TyCon -> OccName
    forall a. NamedThing a => a -> OccName
    getOccName (TyCon -> OccName) -> TyCon -> OccName
    forall a b. (a -> b) -> a -> b
    $ DataCon -> TyCon
    dataConTyCon DataCon
    data_con
       val_descr :: ConstrDescription
    val_descr = String -> ConstrDescription
    BS8.pack (String -> ConstrDescription) -> String -> ConstrDescription
    forall a b. (a -> b) -> a -> b
    $ OccName -> String
    occNameString (OccName -> String) -> OccName -> String
    forall a b. (a -> b) -> a -> b
    $ DataCon -> OccName
    forall a. NamedThing a => a -> OccName
    getOccName DataCon
    data_con

    -- We need a black-hole closure info to pass to @allocDynClosure@ when we
    -- want to allocate the black hole on entry to a CAF.

    cafBlackHoleInfoTable :: CmmInfoTable
    cafBlackHoleInfoTable :: CmmInfoTable
    cafBlackHoleInfoTable
      = CmmInfoTable { cit_lbl :: CLabel
    cit_lbl  = CLabel
    mkCAFBlackHoleInfoTableLabel
                     , cit_rep :: SMRep
    cit_rep  = SMRep
    blackHoleRep
                     , cit_prof :: ProfilingInfo
    cit_prof = ProfilingInfo
    NoProfilingInfo
                     , cit_srt :: Maybe CLabel
    cit_srt  = Maybe CLabel
    forall a. Maybe a
    Nothing
                     , cit_clo :: Maybe (Id, CostCentreStack)
    cit_clo  = Maybe (Id, CostCentreStack)
    forall a. Maybe a
    Nothing }

    indStaticInfoTable :: CmmInfoTable
    indStaticInfoTable :: CmmInfoTable
    indStaticInfoTable
      = CmmInfoTable { cit_lbl :: CLabel
    cit_lbl  = CLabel
    mkIndStaticInfoLabel
                     , cit_rep :: SMRep
    cit_rep  = SMRep
    indStaticRep
                     , cit_prof :: ProfilingInfo
    cit_prof = ProfilingInfo
    NoProfilingInfo
                     , cit_srt :: Maybe CLabel
    cit_srt  = Maybe CLabel
    forall a. Maybe a
    Nothing
                     , cit_clo :: Maybe (Id, CostCentreStack)
    cit_clo  = Maybe (Id, CostCentreStack)
    forall a. Maybe a
    Nothing }

    staticClosureNeedsLink :: Bool -> CmmInfoTable -> Bool
    -- A static closure needs a link field to aid the GC when traversing
    -- the static closure graph.  But it only needs such a field if either
    --        a) it has an SRT
    --        b) it's a constructor with one or more pointer fields
    -- In case (b), the constructor's fields themselves play the role
    -- of the SRT.
    staticClosureNeedsLink :: Bool -> CmmInfoTable -> Bool
    staticClosureNeedsLink Bool
    has_srt CmmInfoTable{ cit_rep :: CmmInfoTable -> SMRep
    cit_rep = SMRep
    smrep }
      | SMRep -> Bool
    isConRep SMRep
    smrep         = Bool -> Bool
    not (SMRep -> Bool
    isStaticNoCafCon SMRep
    smrep)
      | Bool
    otherwise              = Bool
    has_srt