    {-# LANGUAGE DataKinds #-}
    {-# LANGUAGE LambdaCase #-}

    -----------------------------------------------------------------------------
    --
    -- Stg to C-- code generation
    --
    -- (c) The University of Glasgow 2004-2006
    --
    -----------------------------------------------------------------------------

    module GHC.StgToCmm ( codeGen ) where

    import GHC.Prelude as Prelude

    import GHC.StgToCmm.Prof (initCostCentres, ldvEnter)
    import GHC.StgToCmm.Monad
    import GHC.StgToCmm.Env
    import GHC.StgToCmm.Bind
    import GHC.StgToCmm.DataCon
    import GHC.StgToCmm.Layout
    import GHC.StgToCmm.Utils
    import GHC.StgToCmm.Closure
    import GHC.StgToCmm.Config
    import GHC.StgToCmm.Hpc
    import GHC.StgToCmm.Ticky
    import GHC.StgToCmm.Types (ModuleLFInfos)

    import GHC.Cmm
    import GHC.Cmm.Utils
    import GHC.Cmm.CLabel
    import GHC.Cmm.Graph

    import GHC.Stg.Syntax

    import GHC.Types.CostCentre
    import GHC.Types.IPE
    import GHC.Types.HpcInfo
    import GHC.Types.Id
    import GHC.Types.Id.Info
    import GHC.Types.RepType
    import GHC.Types.Basic
    import GHC.Types.Var.Set ( isEmptyDVarSet )
    import GHC.Types.Unique.FM
    import GHC.Types.Name.Env

    import GHC.Core.DataCon
    import GHC.Core.TyCon
    import GHC.Core.Multiplicity

    import GHC.Unit.Module

    import GHC.Utils.Error
    import GHC.Utils.Outputable
    import GHC.Utils.Logger

    import GHC.Utils.TmpFs

    import GHC.Data.Stream
    import GHC.Data.OrdList
    import GHC.Types.Unique.Map

    import Control.Monad (when,void, forM_)
    import GHC.Utils.Misc
    import System.IO.Unsafe
    import qualified Data.ByteString as BS
    import Data.IORef
    import GHC.Utils.Panic

    codeGen :: Logger
            -> TmpFs
            -> StgToCmmConfig
            -> InfoTableProvMap
            -> [TyCon]
            -> CollectedCCs                -- (Local/global) cost-centres needing declaring/registering.
            -> [CgStgTopBinding]           -- Bindings to convert
            -> HpcInfo
            -> Stream IO CmmGroup ModuleLFInfos       -- Output as a stream, so codegen can
                                           -- be interleaved with output

    codeGen :: Logger
    -> TmpFs
    -> StgToCmmConfig
    -> InfoTableProvMap
    -> [TyCon]
    -> CollectedCCs
    -> [CgStgTopBinding]
    -> HpcInfo
    -> Stream IO CmmGroup ModuleLFInfos
    codeGen Logger
    logger TmpFs
    tmpfs StgToCmmConfig
    cfg (InfoTableProvMap (UniqMap UniqFM
      DataCon (DataCon, NonEmpty (WordOff, Maybe IpeSourceLocation))
    denv) ClosureMap
    _ InfoTableToSourceLocationMap
    _) [TyCon]
    data_tycons
            CollectedCCs
    cost_centre_info [CgStgTopBinding]
    stg_binds HpcInfo
    hpc_info
      = do  {     -- cg: run the code generator, and yield the resulting CmmGroup
                  -- Using an IORef to store the state is a bit crude, but otherwise
                  -- we would need to add a state monad layer which regresses
                  -- allocations by 0.5-2%.
            ; cgref <- IO (IORef CgState) -> Stream IO CmmGroup (IORef CgState)
    forall a. IO a -> Stream IO CmmGroup a
    forall (m :: * -> *) a. MonadIO m => IO a -> m a
    liftIO (IO (IORef CgState) -> Stream IO CmmGroup (IORef CgState))
    -> IO (IORef CgState) -> Stream IO CmmGroup (IORef CgState)
    forall a b. (a -> b) -> a -> b
    $ IO CgState
    initC IO CgState -> (CgState -> IO (IORef CgState)) -> IO (IORef CgState)
    forall a b. IO a -> (a -> IO b) -> IO b
    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
    >>= \CgState
    s -> CgState -> IO (IORef CgState)
    forall a. a -> IO (IORef a)
    newIORef CgState
    s
            ; let cg :: FCode a -> Stream IO CmmGroup a
                  cg FCode a
    fcode = do
                    (a, cmm) <- IO (a, CmmGroup) -> Stream IO CmmGroup (a, CmmGroup)
    forall a. IO a -> Stream IO CmmGroup a
    forall (m :: * -> *) a. MonadIO m => IO a -> m a
    liftIO (IO (a, CmmGroup) -> Stream IO CmmGroup (a, CmmGroup))
    -> (IO (a, CmmGroup) -> IO (a, CmmGroup))
    -> IO (a, CmmGroup)
    -> Stream IO CmmGroup (a, CmmGroup)
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Logger
    -> SDoc
    -> ((a, CmmGroup) -> ())
    -> IO (a, CmmGroup)
    -> IO (a, CmmGroup)
    forall (m :: * -> *) a.
    MonadIO m =>
    Logger -> SDoc -> (a -> ()) -> m a -> m a
    withTimingSilent Logger
    logger (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "STG -> Cmm") ((a, CmmGroup) -> () -> ()
    forall a b. a -> b -> b
    `seq` ()) (IO (a, CmmGroup) -> Stream IO CmmGroup (a, CmmGroup))
    -> IO (a, CmmGroup) -> Stream IO CmmGroup (a, CmmGroup)
    forall a b. (a -> b) -> a -> b
    $ do
                             st <- IORef CgState -> IO CgState
    forall a. IORef a -> IO a
    readIORef IORef CgState
    cgref
                             let fstate = Platform -> FCodeState
    initFCodeState (Platform -> FCodeState) -> Platform -> FCodeState
    forall a b. (a -> b) -> a -> b
    $ StgToCmmConfig -> Platform
    stgToCmmPlatform StgToCmmConfig
    cfg
                             let (a,st') = runC cfg fstate st (getCmm fcode)

                             -- NB. stub-out cgs_tops and cgs_stmts.  This fixes
                             -- a big space leak.  DO NOT REMOVE!
                             -- This is observed by the #3294 test
                             writeIORef cgref $! (st'{ cgs_tops = nilOL, cgs_stmts = mkNop })
                             return a
                    yield cmm
                    return a

            ; cg (mkModuleInit cost_centre_info (stgToCmmThisModule cfg) hpc_info)

            ; mapM_ (cg . cgTopBinding logger tmpfs cfg) stg_binds
                    -- Put datatype_stuff after code_stuff, because the
                    -- datatype closure table (for enumeration types) to
                    -- (say) PrelBase_True_closure, which is defined in
                    -- code_stuff
            ; let do_tycon TyCon
    tycon = do
                    -- Generate a table of static closures for an
                    -- enumeration type Note that the closure pointers are
                    -- tagged.
                     Bool -> Stream IO CmmGroup () -> Stream IO CmmGroup ()
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
    when (TyCon -> Bool
    isEnumerationTyCon TyCon
    tycon) (Stream IO CmmGroup () -> Stream IO CmmGroup ())
    -> Stream IO CmmGroup () -> Stream IO CmmGroup ()
    forall a b. (a -> b) -> a -> b
    $ FCode () -> Stream IO CmmGroup ()
    forall a. FCode a -> Stream IO CmmGroup a
    cg (TyCon -> FCode ()
    cgEnumerationTyCon TyCon
    tycon)
                     -- Emit normal info_tables, for data constructors defined in this module.
                     (DataCon -> Stream IO CmmGroup ())
    -> [DataCon] -> Stream IO CmmGroup ()
    forall (t :: * -> *) (m :: * -> *) a b.
    (Foldable t, Monad m) =>
    (a -> m b) -> t a -> m ()
    mapM_ (FCode () -> Stream IO CmmGroup ()
    forall a. FCode a -> Stream IO CmmGroup a
    cg (FCode () -> Stream IO CmmGroup ())
    -> (DataCon -> FCode ()) -> DataCon -> Stream IO CmmGroup ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ConInfoTableLocation -> DataCon -> FCode ()
    cgDataCon ConInfoTableLocation
    DefinitionSite) (TyCon -> [DataCon]
    tyConDataCons TyCon
    tycon)

            ; mapM_ do_tycon data_tycons

            -- Emit special info tables for everything used in this module
            -- This will only do something if  `-fdistinct-info-tables` is turned on.
            ; mapM_ (\(DataCon
    dc, NonEmpty (WordOff, Maybe IpeSourceLocation)
    ns) -> NonEmpty (WordOff, Maybe IpeSourceLocation)
    -> ((WordOff, Maybe IpeSourceLocation) -> Stream IO CmmGroup ())
    -> Stream IO CmmGroup ()
    forall (t :: * -> *) (m :: * -> *) a b.
    (Foldable t, Monad m) =>
    t a -> (a -> m b) -> m ()
    forM_ NonEmpty (WordOff, Maybe IpeSourceLocation)
    ns (((WordOff, Maybe IpeSourceLocation) -> Stream IO CmmGroup ())
     -> Stream IO CmmGroup ())
    -> ((WordOff, Maybe IpeSourceLocation) -> Stream IO CmmGroup ())
    -> Stream IO CmmGroup ()
    forall a b. (a -> b) -> a -> b
    $ \(WordOff
    k, Maybe IpeSourceLocation
    _ss) -> FCode () -> Stream IO CmmGroup ()
    forall a. FCode a -> Stream IO CmmGroup a
    cg (ConInfoTableLocation -> DataCon -> FCode ()
    cgDataCon (Module -> WordOff -> ConInfoTableLocation
    UsageSite (StgToCmmConfig -> Module
    stgToCmmThisModule StgToCmmConfig
    cfg) WordOff
    k) DataCon
    dc)) (nonDetEltsUFM denv)

            ; final_state <- liftIO (readIORef cgref)
            ; let cg_id_infos = CgState -> CgBindings
    cgs_binds CgState
    final_state

              -- See Note [Conveying CAF-info and LFInfo between modules] in
              -- GHC.StgToCmm.Types
            ; let extractInfo CgIdInfo
    info = (Name
    name, LambdaFormInfo
    lf)
                    where
                      !name :: Name
    name = Var -> Name
    idName (CgIdInfo -> Var
    cg_id CgIdInfo
    info)
                      !lf :: LambdaFormInfo
    lf = CgIdInfo -> LambdaFormInfo
    cg_lf CgIdInfo
    info

                  !generatedInfo
                    | StgToCmmConfig -> Bool
    stgToCmmOmitIfPragmas StgToCmmConfig
    cfg
                    = ModuleLFInfos
    forall a. NameEnv a
    emptyNameEnv
                    | Bool
    otherwise
                    = [(Name, LambdaFormInfo)] -> ModuleLFInfos
    forall a. [(Name, a)] -> NameEnv a
    mkNameEnv ((CgIdInfo -> (Name, LambdaFormInfo))
    -> [CgIdInfo] -> [(Name, LambdaFormInfo)]
    forall a b. (a -> b) -> [a] -> [b]
    Prelude.map CgIdInfo -> (Name, LambdaFormInfo)
    extractInfo (CgBindings -> [CgIdInfo]
    forall {k} (key :: k) elt. UniqFM key elt -> [elt]
    nonDetEltsUFM CgBindings
    cg_id_infos))

            ; return generatedInfo
            }

    ---------------------------------------------------------------
    --      Top-level bindings
    ---------------------------------------------------------------

    {- 'cgTopBinding' is only used for top-level bindings, since they need
    to be allocated statically (not in the heap) and need to be labelled.
    No unboxed bindings can happen at top level.

    In the code below, the static bindings are accumulated in the
    @MkCgState@, and transferred into the ``statics'' slot by @forkStatics@.
    This is so that we can write the top level processing in a compositional
    style, with the increasing static environment being plumbed as a state
    variable. -}

    cgTopBinding :: Logger -> TmpFs -> StgToCmmConfig -> CgStgTopBinding -> FCode ()
    cgTopBinding :: Logger -> TmpFs -> StgToCmmConfig -> CgStgTopBinding -> FCode ()
    cgTopBinding Logger
    logger TmpFs
    tmpfs StgToCmmConfig
    cfg = \case
        StgTopLifted (StgNonRec BinderP 'CodeGen
    id GenStgRhs 'CodeGen
    rhs) -> do
            let (CgIdInfo
    info, FCode ()
    fcode) = StgToCmmConfig
    -> RecFlag -> Var -> GenStgRhs 'CodeGen -> (CgIdInfo, FCode ())
    cgTopRhs StgToCmmConfig
    cfg RecFlag
    NonRecursive Var
    BinderP 'CodeGen
    id GenStgRhs 'CodeGen
    rhs
            FCode ()
    fcode
            CgIdInfo -> FCode ()
    addBindC CgIdInfo
    info

        StgTopLifted (StgRec [(BinderP 'CodeGen, GenStgRhs 'CodeGen)]
    pairs) -> do
            let ([Var]
    bndrs, [GenStgRhs 'CodeGen]
    rhss) = [(Var, GenStgRhs 'CodeGen)] -> ([Var], [GenStgRhs 'CodeGen])
    forall a b. [(a, b)] -> ([a], [b])
    unzip [(Var, GenStgRhs 'CodeGen)]
    [(BinderP 'CodeGen, GenStgRhs 'CodeGen)]
    pairs
            let pairs' :: [(Var, GenStgRhs 'CodeGen)]
    pairs' = [Var] -> [GenStgRhs 'CodeGen] -> [(Var, GenStgRhs 'CodeGen)]
    forall a b. [a] -> [b] -> [(a, b)]
    zip [Var]
    bndrs [GenStgRhs 'CodeGen]
    rhss
                r :: [(CgIdInfo, FCode ())]
    r = (Var -> GenStgRhs 'CodeGen -> (CgIdInfo, FCode ()))
    -> [(Var, GenStgRhs 'CodeGen)] -> [(CgIdInfo, FCode ())]
    forall a b c. (a -> b -> c) -> [(a, b)] -> [c]
    unzipWith (StgToCmmConfig
    -> RecFlag -> Var -> GenStgRhs 'CodeGen -> (CgIdInfo, FCode ())
    cgTopRhs StgToCmmConfig
    cfg RecFlag
    Recursive) [(Var, GenStgRhs 'CodeGen)]
    pairs'
                ([CgIdInfo]
    infos, [FCode ()]
    fcodes) = [(CgIdInfo, FCode ())] -> ([CgIdInfo], [FCode ()])
    forall a b. [(a, b)] -> ([a], [b])
    unzip [(CgIdInfo, FCode ())]
    r
            [CgIdInfo] -> FCode ()
    addBindsC [CgIdInfo]
    infos
            [FCode ()] -> FCode ()
    forall (t :: * -> *) (m :: * -> *) a.
    (Foldable t, Monad m) =>
    t (m a) -> m ()
    sequence_ [FCode ()]
    fcodes

        StgTopStringLit Var
    id ByteString
    str -> do
            let label :: CLabel
    label = Name -> CLabel
    mkBytesLabel (Var -> Name
    idName Var
    id)
            -- emit either a CmmString literal or dump the string in a file and emit a
            -- CmmFileEmbed literal.  If binary blobs aren't supported,
            -- the threshold in `cfg` will be 0.
            -- See Note [Embedding large binary blobs] in GHC.CmmToAsm.Ppr
            let asString :: Bool
    asString = case StgToCmmConfig -> Maybe Word
    stgToCmmBinBlobThresh StgToCmmConfig
    cfg of
                  Just Word
    bin_blob_threshold -> WordOff -> Word
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral (ByteString -> WordOff
    BS.length ByteString
    str) Word -> Word -> Bool
    forall a. Ord a => a -> a -> Bool
    <= Word
    bin_blob_threshold
                  Maybe Word
    Nothing                -> Bool
    True

                (CmmLit
    lit,CmmDecl
    decl) = if Bool
    asString
                  then CLabel -> ByteString -> (CmmLit, CmmDecl)
    forall (raw :: Bool) info stmt.
    CLabel
    -> ByteString -> (CmmLit, GenCmmDecl (GenCmmStatics raw) info stmt)
    mkByteStringCLit CLabel
    label ByteString
    str
                  else IO (CmmLit, CmmDecl) -> (CmmLit, CmmDecl)
    forall a. IO a -> a
    unsafePerformIO (IO (CmmLit, CmmDecl) -> (CmmLit, CmmDecl))
    -> IO (CmmLit, CmmDecl) -> (CmmLit, CmmDecl)
    forall a b. (a -> b) -> a -> b
    $ do
                         bFile <- Logger
    -> TmpFs -> TempDir -> TempFileLifetime -> String -> IO String
    newTempName Logger
    logger TmpFs
    tmpfs (StgToCmmConfig -> TempDir
    stgToCmmTmpDir StgToCmmConfig
    cfg) TempFileLifetime
    TFL_CurrentModule String
    ".dat"
                         BS.writeFile bFile str
                         return $ mkFileEmbedLit label bFile (BS.length str)
            CmmDecl -> FCode ()
    emitDecl CmmDecl
    decl
            CgIdInfo -> FCode ()
    addBindC (Platform -> Var -> LambdaFormInfo -> CmmLit -> CgIdInfo
    litIdInfo (StgToCmmConfig -> Platform
    stgToCmmPlatform StgToCmmConfig
    cfg) Var
    id LambdaFormInfo
    mkLFStringLit CmmLit
    lit)

    cgTopRhs :: StgToCmmConfig -> RecFlag -> Id -> CgStgRhs -> (CgIdInfo, FCode ())
            -- The Id is passed along for setting up a binding...

    cgTopRhs :: StgToCmmConfig
    -> RecFlag -> Var -> GenStgRhs 'CodeGen -> (CgIdInfo, FCode ())
    cgTopRhs StgToCmmConfig
    cfg RecFlag
    _rec Var
    bndr (StgRhsCon CostCentreStack
    _cc DataCon
    con ConstructorNumber
    mn [StgTickish]
    _ts [StgArg]
    args Type
    _typ)
      = StgToCmmConfig
    -> Var
    -> DataCon
    -> ConstructorNumber
    -> [NonVoid StgArg]
    -> (CgIdInfo, FCode ())
    cgTopRhsCon StgToCmmConfig
    cfg Var
    bndr DataCon
    con ConstructorNumber
    mn ([StgArg] -> [NonVoid StgArg]
    assertNonVoidStgArgs [StgArg]
    args)
          -- con args are always non-void,
          -- see Note [Post-unarisation invariants] in GHC.Stg.Unarise

    cgTopRhs StgToCmmConfig
    cfg RecFlag
    rec Var
    bndr (StgRhsClosure XRhsClosure 'CodeGen
    fvs CostCentreStack
    cc UpdateFlag
    upd_flag [BinderP 'CodeGen]
    args GenStgExpr 'CodeGen
    body Type
    _typ)
      = Bool -> SDoc -> (CgIdInfo, FCode ()) -> (CgIdInfo, FCode ())
    forall a. HasCallStack => Bool -> SDoc -> a -> a
    assertPpr (DIdSet -> Bool
    isEmptyDVarSet DIdSet
    XRhsClosure 'CodeGen
    fvs) (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "fvs:" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> DIdSet -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr DIdSet
    XRhsClosure 'CodeGen
    fvs) ((CgIdInfo, FCode ()) -> (CgIdInfo, FCode ()))
    -> (CgIdInfo, FCode ()) -> (CgIdInfo, FCode ())
    forall a b. (a -> b) -> a -> b
    $   -- There should be no free variables
        Platform
    -> RecFlag
    -> Var
    -> CostCentreStack
    -> UpdateFlag
    -> [Var]
    -> GenStgExpr 'CodeGen
    -> (CgIdInfo, FCode ())
    cgTopRhsClosure (StgToCmmConfig -> Platform
    stgToCmmPlatform StgToCmmConfig
    cfg) RecFlag
    rec Var
    bndr CostCentreStack
    cc UpdateFlag
    upd_flag [Var]
    [BinderP 'CodeGen]
    args GenStgExpr 'CodeGen
    body

    ---------------------------------------------------------------
    --      Module initialisation code
    ---------------------------------------------------------------

    mkModuleInit
            :: CollectedCCs         -- cost centre info
            -> Module
            -> HpcInfo
            -> FCode ()

    mkModuleInit :: CollectedCCs -> Module -> HpcInfo -> FCode ()
    mkModuleInit CollectedCCs
    cost_centre_info Module
    this_mod HpcInfo
    hpc_info
      = do  { Module -> HpcInfo -> FCode ()
    initHpc Module
    this_mod HpcInfo
    hpc_info
            ; CollectedCCs -> FCode ()
    initCostCentres CollectedCCs
    cost_centre_info
            }

    ---------------------------------------------------------------
    --      Generating static stuff for algebraic data types
    ---------------------------------------------------------------

    cgEnumerationTyCon :: TyCon -> FCode ()
    cgEnumerationTyCon :: TyCon -> FCode ()
    cgEnumerationTyCon TyCon
    tycon
      = do platform <- FCode Platform
    getPlatform
           emitRODataLits (mkClosureTableLabel (tyConName tycon) NoCafRefs)
                 [ CmmLabelOff (mkClosureLabel (dataConName con) NoCafRefs)
                               (tagForCon platform con)
                 | con <- tyConDataCons tycon]

    cgDataCon :: ConInfoTableLocation -> DataCon -> FCode ()
    -- Generate the entry code, info tables, and (for niladic constructor)
    -- the static closure, for a constructor.
    cgDataCon :: ConInfoTableLocation -> DataCon -> FCode ()
    cgDataCon ConInfoTableLocation
    mn DataCon
    data_con
      = do  { Bool -> FCode ()
    forall (m :: * -> *). (HasCallStack, Applicative m) => Bool -> m ()
    massert (Bool -> Bool
    not (DataCon -> Bool
    isUnboxedTupleDataCon DataCon
    data_con Bool -> Bool -> Bool
    || DataCon -> Bool
    isUnboxedSumDataCon DataCon
    data_con))
            ; profile <- FCode Profile
    getProfile
            ; platform <- getPlatform
            ; let
                (tot_wds, --  #ptr_wds + #nonptr_wds
                 ptr_wds) --  #ptr_wds
                  = mkVirtConstrSizes profile arg_reps

                nonptr_wds   = WordOff
    tot_wds WordOff -> WordOff -> WordOff
    forall a. Num a => a -> a -> a
    - WordOff
    ptr_wds

                dyn_info_tbl =
                  Profile
    -> DataCon
    -> ConInfoTableLocation
    -> Bool
    -> WordOff
    -> WordOff
    -> CmmInfoTable
    mkDataConInfoTable Profile
    profile DataCon
    data_con ConInfoTableLocation
    mn Bool
    False WordOff
    ptr_wds WordOff
    nonptr_wds

                -- We're generating info tables, so we don't know and care about
                -- what the actual arguments are. Using () here as the place holder.
                arg_reps :: [PrimRep]
                arg_reps = [ PrimRep
    rep_ty
                           | Scaled Type
    ty <- DataCon -> [Scaled Type]
    dataConRepArgTys DataCon
    data_con
                           , PrimRep
    rep_ty <- HasDebugCallStack => Type -> [PrimRep]
    Type -> [PrimRep]
    typePrimRep (Scaled Type -> Type
    forall a. Scaled a -> a
    scaledThing Scaled Type
    ty)
                           ]

            ; emitClosureAndInfoTable platform dyn_info_tbl NativeDirectCall [] $
                -- NB: the closure pointer is assumed *untagged* on
                -- entry to a constructor.  If the pointer is tagged,
                -- then we should not be entering it.  This assumption
                -- is used in ldvEnter and when tagging the pointer to
                -- return it.
                -- NB 2: We don't set CC when entering data (WDP 94/06)
                do { tickyEnterDynCon
                   ; let node = CmmReg -> CmmExpr
    CmmReg (CmmReg -> CmmExpr) -> CmmReg -> CmmExpr
    forall a b. (a -> b) -> a -> b
    $ Platform -> CmmReg
    nodeReg Platform
    platform
                   ; ldvEnter node
                   ; tickyReturnOldCon (length arg_reps)
                   ; void $ emitReturn [cmmOffsetB platform node (tagForCon platform data_con)]
                   }
                        -- The case continuation code expects a tagged pointer
            }