{-
(c) The University of Glasgow 2006
(c) The AQUA Project, Glasgow University, 1998

-}


{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ViewPatterns #-}

-- | Typechecking @foreign@ declarations
--
-- A foreign declaration is used to either give an externally
-- implemented function a Haskell type (and calling interface) or
-- give a Haskell function an external calling interface. Either way,
-- the range of argument and result types these functions can accommodate
-- is restricted to what the outside world understands (read C), and this
-- module checks to see if a foreign declaration has got a legal type.
module GHC.Tc.Gen.Foreign
        ( tcForeignImports
        , tcForeignExports

        -- Low-level exports for hooks
        , isForeignImport, isForeignExport
        , tcFImport, tcFExport
        , tcForeignImports'
        , tcCheckFIType, checkCTarget, checkForeignArgs, checkForeignRes
        , normaliseFfiType
        , nonIOok, mustBeIO
        , checkSafe, noCheckSafe
        , tcForeignExports'
        , tcCheckFEType
        ) where

import GHC.Prelude

import GHC.Hs

import GHC.Tc.Errors.Types
import GHC.Tc.Utils.Monad
import GHC.Tc.Gen.HsType
import GHC.Tc.Gen.Expr
import GHC.Tc.Utils.Env
import GHC.Tc.Utils.TcType
import GHC.Tc.Instance.Family

import GHC.Core.FamInstEnv
import GHC.Core.Coercion
import GHC.Core.Reduction
import GHC.Core.Type
import GHC.Core.Multiplicity
import GHC.Core.DataCon
import GHC.Core.TyCon
import GHC.Core.TyCon.RecWalk

import GHC.Types.ForeignCall
import GHC.Types.Id
import GHC.Types.Name
import GHC.Types.Name.Reader
import GHC.Types.SrcLoc

import GHC.Builtin.Names
import GHC.Builtin.Types.Prim( isArrowTyCon )

import GHC.Driver.Session
import GHC.Driver.Backend

import GHC.Utils.Error
import GHC.Utils.Outputable as Outputable
import GHC.Utils.Panic
import GHC.Utils.Unique
import GHC.Platform

import GHC.Data.Bag
import GHC.Driver.Hooks
import qualified GHC.LanguageExtensions as LangExt

import Control.Monad ( zipWithM )
import Control.Monad.Trans.Writer.CPS
  ( WriterT, runWriterT, tell )
import Control.Monad.Trans.Class
  ( lift )
import Data.Maybe (isJust)
import GHC.Builtin.Types (unitTyCon)

-- Defines a binding
isForeignImport :: forall name. UnXRec name => LForeignDecl name -> Bool
isForeignImport :: forall name. UnXRec name => LForeignDecl name -> Bool
isForeignImport (forall p a. UnXRec p => XRec p a -> a
unXRec @name -> ForeignImport {}) = Bool
True
isForeignImport LForeignDecl name
_                        = Bool
False

-- Exports a binding
isForeignExport :: forall name. UnXRec name => LForeignDecl name -> Bool
isForeignExport :: forall name. UnXRec name => LForeignDecl name -> Bool
isForeignExport (forall p a. UnXRec p => XRec p a -> a
unXRec @name -> ForeignExport {}) = Bool
True
isForeignExport LForeignDecl name
_                        = Bool
False

{-
Note [Don't recur in normaliseFfiType']
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
normaliseFfiType' is the workhorse for normalising a type used in a foreign
declaration. If we have

newtype Age = MkAge Int

we want to see that Age -> IO () is the same as Int -> IO (). But, we don't
need to recur on any type parameters, because no parameterized types (with
interesting parameters) are marshalable! The full list of marshalable types
is in the body of boxedMarshalableTyCon in GHC.Tc.Utils.TcType. The only members of that
list not at kind * are Ptr, FunPtr, and StablePtr, all of which get marshaled
the same way regardless of type parameter. So, no need to recur into
parameters.

Similarly, we don't need to look in AppTy's, because nothing headed by
an AppTy will be marshalable.
-}

-- normaliseFfiType takes the type from an FFI declaration, and
-- evaluates any type synonyms, type functions, and newtypes. However,
-- we are only allowed to look through newtypes if the constructor is
-- in scope.  We return a bag of all the newtype constructors thus found.
-- Always returns a Representational coercion
normaliseFfiType :: Type -> TcM (Reduction, Bag GlobalRdrElt)
normaliseFfiType :: Type -> TcM (Reduction, Bag GlobalRdrElt)
normaliseFfiType Type
ty
    = do fam_envs <- TcM FamInstEnvs
tcGetFamInstEnvs
         normaliseFfiType' fam_envs ty

normaliseFfiType' :: FamInstEnvs -> Type -> TcM (Reduction, Bag GlobalRdrElt)
normaliseFfiType' :: FamInstEnvs -> Type -> TcM (Reduction, Bag GlobalRdrElt)
normaliseFfiType' FamInstEnvs
env Type
ty0 = WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
-> TcM (Reduction, Bag GlobalRdrElt)
forall w (m :: * -> *) a. Monoid w => WriterT w m a -> m (a, w)
runWriterT (WriterT
   (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
 -> TcM (Reduction, Bag GlobalRdrElt))
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
-> TcM (Reduction, Bag GlobalRdrElt)
forall a b. (a -> b) -> a -> b
$ Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
Representational RecTcChecker
initRecTc Type
ty0
  where
    go :: Role -> RecTcChecker -> Type -> WriterT (Bag GlobalRdrElt) TcM Reduction
    go :: Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
role RecTcChecker
rec_nts Type
ty
      | Just Type
ty' <- Type -> Maybe Type
coreView Type
ty     -- Expand synonyms
      = Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
role RecTcChecker
rec_nts Type
ty'

      | Just (TyCon
tc, [Type]
tys) <- HasDebugCallStack => Type -> Maybe (TyCon, [Type])
Type -> Maybe (TyCon, [Type])
splitTyConApp_maybe Type
ty
      = Role
-> RecTcChecker
-> TyCon
-> [Type]
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go_tc_app Role
role RecTcChecker
rec_nts TyCon
tc [Type]
tys

      | ([ForAllTyBinder]
bndrs, Type
inner_ty) <- Type -> ([ForAllTyBinder], Type)
splitForAllForAllTyBinders Type
ty
      , Bool -> Bool
not ([ForAllTyBinder] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [ForAllTyBinder]
bndrs)
      = do redn <- Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
role RecTcChecker
rec_nts Type
inner_ty
           return $ mkHomoForAllRedn bndrs redn

      | Bool
otherwise -- see Note [Don't recur in normaliseFfiType']
      = Reduction
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
forall a.
a -> WriterT (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Reduction
 -> WriterT
      (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction)
-> Reduction
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
forall a b. (a -> b) -> a -> b
$ Role -> Type -> Reduction
mkReflRedn Role
role Type
ty

    go_tc_app :: Role -> RecTcChecker -> TyCon -> [Type]
              -> WriterT (Bag GlobalRdrElt) TcM Reduction
    go_tc_app :: Role
-> RecTcChecker
-> TyCon
-> [Type]
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go_tc_app Role
role RecTcChecker
rec_nts TyCon
tc [Type]
tys
        | TyCon -> Bool
isArrowTyCon TyCon
tc  -- Recurse through arrows, or at least the top
        = WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
children_only    -- level arrows.  Remember, the default case is
                           -- "don't recurse" (see last eqn for go_tc_app)

        | Unique
tc_key Unique -> [Unique] -> Bool
forall a. Eq a => a -> [a] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [Unique
ioTyConKey, Unique
funPtrTyConKey]
        -- We don't want to look through the IO newtype, even if it is
        -- in scope, so we have a special case for it:
        = WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
children_only

        | TyCon -> Bool
isNewTyCon TyCon
tc         -- Expand newtypes
        , Just RecTcChecker
rec_nts' <- RecTcChecker -> TyCon -> Maybe RecTcChecker
checkRecTc RecTcChecker
rec_nts TyCon
tc
                   -- See Note [Expanding newtypes and products] in GHC.Core.TyCon.RecWalk
                   -- We can't just use isRecursiveTyCon; sometimes recursion is ok:
                   --     newtype T = T (Ptr T)
                   --   Here, we don't reject the type for being recursive.
                   -- If this is a recursive newtype then it will normally
                   -- be rejected later as not being a valid FFI type.
        = do { rdr_env <- IOEnv (Env TcGblEnv TcLclEnv) GlobalRdrEnv
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) GlobalRdrEnv
forall (m :: * -> *) a.
Monad m =>
m a -> WriterT (Bag GlobalRdrElt) m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift (IOEnv (Env TcGblEnv TcLclEnv) GlobalRdrEnv
 -> WriterT
      (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) GlobalRdrEnv)
-> IOEnv (Env TcGblEnv TcLclEnv) GlobalRdrEnv
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) GlobalRdrEnv
forall a b. (a -> b) -> a -> b
$ IOEnv (Env TcGblEnv TcLclEnv) GlobalRdrEnv
getGlobalRdrEnv
             ; case checkNewtypeFFI rdr_env tc of
                 Maybe GlobalRdrElt
Nothing  -> WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
nothing
                 Just GlobalRdrElt
gre ->
                   do { redn <- Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
role RecTcChecker
rec_nts' Type
nt_rhs
                      ; tell (unitBag gre)
                      ; return $ nt_co `mkTransRedn` redn } }

        | TyCon -> Bool
isFamilyTyCon TyCon
tc              -- Expand open tycons
        , Reduction Coercion
co Type
ty <- FamInstEnvs -> Role -> TyCon -> [Type] -> Reduction
normaliseTcApp FamInstEnvs
env Role
role TyCon
tc [Type]
tys
        , Bool -> Bool
not (Coercion -> Bool
isReflexiveCo Coercion
co)
        = do redn <- Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
role RecTcChecker
rec_nts Type
ty
             return $ co `mkTransRedn` redn

        | Bool
otherwise
        = WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
nothing -- see Note [Don't recur in normaliseFfiType']
        where
          tc_key :: Unique
tc_key = TyCon -> Unique
forall a. Uniquable a => a -> Unique
getUnique TyCon
tc
          children_only :: WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
children_only
            = do { args <- [Reduction] -> Reductions
unzipRedns ([Reduction] -> Reductions)
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) [Reduction]
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reductions
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$>
                            (Type
 -> Role
 -> WriterT
      (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction)
-> [Type]
-> [Role]
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) [Reduction]
forall (m :: * -> *) a b c.
Applicative m =>
(a -> b -> m c) -> [a] -> [b] -> m [c]
zipWithM ( \ Type
ty Role
r -> Role
-> RecTcChecker
-> Type
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
go Role
r RecTcChecker
rec_nts Type
ty )
                                     [Type]
tys (Role -> TyCon -> [Role]
tyConRoleListX Role
role TyCon
tc)
                 ; return $ mkTyConAppRedn role tc args }
          nt_co :: Coercion
nt_co  = Role -> CoAxiom Unbranched -> [Type] -> [Coercion] -> Coercion
mkUnbranchedAxInstCo Role
role (TyCon -> CoAxiom Unbranched
newTyConCo TyCon
tc) [Type]
tys []
          nt_rhs :: Type
nt_rhs = TyCon -> [Type] -> Type
newTyConInstRhs TyCon
tc [Type]
tys

          ty :: Type
ty      = TyCon -> [Type] -> Type
mkTyConApp TyCon
tc [Type]
tys
          nothing :: WriterT
  (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
nothing = Reduction
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
forall a.
a -> WriterT (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Reduction
 -> WriterT
      (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction)
-> Reduction
-> WriterT
     (Bag GlobalRdrElt) (IOEnv (Env TcGblEnv TcLclEnv)) Reduction
forall a b. (a -> b) -> a -> b
$ Role -> Type -> Reduction
mkReflRedn Role
role Type
ty

checkNewtypeFFI :: GlobalRdrEnv -> TyCon -> Maybe GlobalRdrElt
checkNewtypeFFI :: GlobalRdrEnv -> TyCon -> Maybe GlobalRdrElt
checkNewtypeFFI GlobalRdrEnv
rdr_env TyCon
tc
  | Just DataCon
con <- TyCon -> Maybe DataCon
tyConSingleDataCon_maybe TyCon
tc
  , Just GlobalRdrElt
gre <- GlobalRdrEnv -> Name -> Maybe GlobalRdrElt
forall info.
Outputable info =>
GlobalRdrEnvX info -> Name -> Maybe (GlobalRdrEltX info)
lookupGRE_Name GlobalRdrEnv
rdr_env (DataCon -> Name
dataConName DataCon
con)
  = GlobalRdrElt -> Maybe GlobalRdrElt
forall a. a -> Maybe a
Just GlobalRdrElt
gre    -- See Note [Newtype constructor usage in foreign declarations]
  | Bool
otherwise
  = Maybe GlobalRdrElt
forall a. Maybe a
Nothing

{-
Note [Newtype constructor usage in foreign declarations]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GHC automatically "unwraps" newtype constructors in foreign import/export
declarations.  In effect that means that a newtype data constructor is
used even though it is not mentioned expclitly in the source, so we don't
want to report it as "defined but not used" or "imported but not used".
eg     newtype D = MkD Int
       foreign import foo :: D -> IO ()
Here 'MkD' is used.  See #7408.

GHC also expands type functions during this process, so it's not enough
just to look at the free variables of the declaration.
eg     type instance F Bool = D
       foreign import bar :: F Bool -> IO ()
Here again 'MkD' is used.

So we really have wait until the type checker to decide what is used.
That's why tcForeignImports and tecForeignExports return a (Bag GRE)
for the newtype constructors they see. Then GHC.Tc.Module can add them
to the module's usages.


************************************************************************
*                                                                      *
\subsection{Imports}
*                                                                      *
************************************************************************
-}

tcForeignImports :: [LForeignDecl GhcRn]
                 -> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignImports :: [LForeignDecl GhcRn]
-> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignImports [LForeignDecl GhcRn]
decls = do
    hooks <- IOEnv (Env TcGblEnv TcLclEnv) Hooks
forall (m :: * -> *). HasHooks m => m Hooks
getHooks
    case tcForeignImportsHook hooks of
        Maybe
  ([LForeignDecl GhcRn]
   -> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt))
Nothing -> [LForeignDecl GhcRn]
-> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignImports' [LForeignDecl GhcRn]
decls
        Just [LForeignDecl GhcRn]
-> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
h  -> [LForeignDecl GhcRn]
-> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
h [LForeignDecl GhcRn]
decls

tcForeignImports' :: [LForeignDecl GhcRn]
                  -> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
-- For the (Bag GlobalRdrElt) result,
-- see Note [Newtype constructor usage in foreign declarations]
tcForeignImports' :: [LForeignDecl GhcRn]
-> TcM ([Id], [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignImports' [LForeignDecl GhcRn]
decls
  = do { (ids, decls, gres) <- (GenLocated SrcSpanAnnA (ForeignDecl GhcRn)
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (Id, GenLocated SrcSpanAnnA (ForeignDecl GhcTc), Bag GlobalRdrElt))
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([Id], [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)],
      [Bag GlobalRdrElt])
forall (m :: * -> *) a b c d.
Monad m =>
(a -> m (b, c, d)) -> [a] -> m ([b], [c], [d])
mapAndUnzip3M LForeignDecl GhcRn
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
GenLocated SrcSpanAnnA (ForeignDecl GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Id, GenLocated SrcSpanAnnA (ForeignDecl GhcTc), Bag GlobalRdrElt)
tcFImport ([GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      ([Id], [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)],
       [Bag GlobalRdrElt]))
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([Id], [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)],
      [Bag GlobalRdrElt])
forall a b. (a -> b) -> a -> b
$
                               (GenLocated SrcSpanAnnA (ForeignDecl GhcRn) -> Bool)
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
forall a. (a -> Bool) -> [a] -> [a]
filter LForeignDecl GhcRn -> Bool
GenLocated SrcSpanAnnA (ForeignDecl GhcRn) -> Bool
forall name. UnXRec name => LForeignDecl name -> Bool
isForeignImport [LForeignDecl GhcRn]
[GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
decls
       ; return (ids, decls, unionManyBags gres) }

tcFImport :: LForeignDecl GhcRn
          -> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
tcFImport :: LForeignDecl GhcRn
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
tcFImport (L SrcSpanAnnA
dloc fo :: ForeignDecl GhcRn
fo@(ForeignImport { fd_name :: forall pass. ForeignDecl pass -> LIdP pass
fd_name = L SrcSpanAnnN
nloc Name
nm, fd_sig_ty :: forall pass. ForeignDecl pass -> LHsSigType pass
fd_sig_ty = LHsSigType GhcRn
hs_ty
                                    , fd_fi :: forall pass. ForeignDecl pass -> ForeignImport pass
fd_fi = ForeignImport GhcRn
imp_decl }))
  = SrcSpanAnnA
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
forall ann a. EpAnn ann -> TcRn a -> TcRn a
setSrcSpanA SrcSpanAnnA
dloc (TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
 -> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt))
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
forall a b. (a -> b) -> a -> b
$ SDoc
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (ForeignDecl GhcRn -> SDoc
foreignDeclCtxt ForeignDecl GhcRn
fo)  (TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
 -> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt))
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
-> TcM (Id, LForeignDecl GhcTc, Bag GlobalRdrElt)
forall a b. (a -> b) -> a -> b
$
    do { sig_ty <- UserTypeCtxt -> LHsSigType GhcRn -> TcM Type
tcHsSigType (Name -> UserTypeCtxt
ForSigCtxt Name
nm) LHsSigType GhcRn
hs_ty
       ; (Reduction norm_co norm_sig_ty, gres) <- normaliseFfiType sig_ty
       ; let
             -- Drop the foralls before inspecting the
             -- structure of the foreign type.
             -- Use splitFunTys, which splits (=>) as well as (->)
             -- so that for  foreign import foo :: Eq a => a -> blah
             -- we get "unacceptable argument Eq a" rather than
             --        "unacceptable result Eq a => a -> blah"
             -- Not a big deal.  We could make a better error message specially
             -- for overloaded functions, but doesn't seem worth it
             (arg_tys, res_ty) = splitFunTys (dropForAlls norm_sig_ty)

             id = HasDebugCallStack => Name -> Type -> Type -> Id
Name -> Type -> Type -> Id
mkLocalId Name
nm Type
ManyTy Type
sig_ty
                 -- Use a LocalId to obey the invariant that locally-defined
                 -- things are LocalIds.  However, it does not need zonking,
                 -- (so GHC.Tc.Zonk.Type.zonkForeignExports ignores it).

       ; imp_decl' <- tcCheckFIType arg_tys res_ty imp_decl
          -- Can't use sig_ty here because sig_ty :: Type and
          -- we need HsType Id hence the undefined
       ; let fi_decl = ForeignImport { fd_name :: LIdP GhcTc
fd_name = SrcSpanAnnN -> Id -> GenLocated SrcSpanAnnN Id
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnN
nloc Id
id
                                     , fd_sig_ty :: LHsSigType GhcTc
fd_sig_ty = LHsSigType GhcTc
GenLocated SrcSpanAnnA (HsSigType GhcTc)
forall a. HasCallStack => a
undefined
                                     , fd_i_ext :: XForeignImport GhcTc
fd_i_ext = Coercion -> Coercion
mkSymCo Coercion
norm_co
                                     , fd_fi :: ForeignImport GhcTc
fd_fi = ForeignImport GhcTc
imp_decl' }
       ; return (id, L dloc fi_decl, gres) }
tcFImport LForeignDecl GhcRn
d = String
-> SDoc
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Id, GenLocated SrcSpanAnnA (ForeignDecl GhcTc), Bag GlobalRdrElt)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"tcFImport" (GenLocated SrcSpanAnnA (ForeignDecl GhcRn) -> SDoc
forall a. Outputable a => a -> SDoc
ppr LForeignDecl GhcRn
GenLocated SrcSpanAnnA (ForeignDecl GhcRn)
d)

-- ------------ Checking types for foreign import ----------------------

tcCheckFIType :: [Scaled Type] -> Type -> ForeignImport GhcRn -> TcM (ForeignImport GhcTc)

tcCheckFIType :: [Scaled Type]
-> Type -> ForeignImport GhcRn -> TcM (ForeignImport GhcTc)
tcCheckFIType [Scaled Type]
arg_tys Type
res_ty idecl :: ForeignImport GhcRn
idecl@(CImport XCImport GhcRn
src (L EpaLocation
lc CCallConv
cconv) XRec GhcRn Safety
safety Maybe Header
mh l :: CImportSpec
l@(CLabel CLabelString
_))
  -- Foreign import label
  = do Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) Backend -> Validity' ExpectedBackends
backendValidityOfCImport
       -- NB check res_ty not sig_ty!
       --    In case sig_ty is (forall a. ForeignPtr a)
       Validity' IllegalForeignTypeReason
-> (IllegalForeignTypeReason -> TcRnMessage) -> TcM ()
check (Type -> Validity' IllegalForeignTypeReason
isFFILabelTy ([Scaled Type] -> Type -> Type
HasDebugCallStack => [Scaled Type] -> Type -> Type
mkScaledFunTys [Scaled Type]
arg_tys Type
res_ty))
             (Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType Maybe ArgOrResult
forall a. Maybe a
Nothing)
       cconv' <- Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) CCallConv
cconv
       return (CImport src (L lc cconv') safety mh l)

tcCheckFIType [Scaled Type]
arg_tys Type
res_ty idecl :: ForeignImport GhcRn
idecl@(CImport XCImport GhcRn
src (L EpaLocation
lc CCallConv
cconv) XRec GhcRn Safety
safety Maybe Header
mh CImportSpec
CWrapper) = do
        -- Foreign wrapper (former f.e.d.)
        -- The type must be of the form ft -> IO (FunPtr ft), where ft is a valid
        -- foreign type.  For legacy reasons ft -> IO (Ptr ft) is accepted, too.
        -- The use of the latter form is DEPRECATED, though.
    Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) Backend -> Validity' ExpectedBackends
backendValidityOfCImport
    cconv' <- Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) CCallConv
cconv
    case arg_tys of
        [Scaled Type
arg1_mult Type
arg1_ty] -> do
                        Type -> TcM ()
checkNoLinearFFI Type
arg1_mult
                        (Type -> Validity' IllegalForeignTypeReason)
-> [Scaled Type] -> TcM ()
checkForeignArgs Type -> Validity' IllegalForeignTypeReason
isFFIExternalTy [Scaled Type]
arg1_tys
                        Bool
-> Bool
-> (Type -> Validity' IllegalForeignTypeReason)
-> Type
-> TcM ()
checkForeignRes Bool
nonIOok  Bool
checkSafe Type -> Validity' IllegalForeignTypeReason
isFFIExportResultTy Type
res1_ty
                        Bool
-> Bool
-> (Type -> Validity' IllegalForeignTypeReason)
-> Type
-> TcM ()
checkForeignRes Bool
mustBeIO Bool
checkSafe (Type -> Type -> Validity' IllegalForeignTypeReason
isFFIDynTy Type
arg1_ty) Type
res_ty
                  where
                     ([Scaled Type]
arg1_tys, Type
res1_ty) = Type -> ([Scaled Type], Type)
tcSplitFunTys Type
arg1_ty
        [Scaled Type]
_ -> TcRnMessage -> TcM ()
addErrTc (Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType Maybe ArgOrResult
forall a. Maybe a
Nothing IllegalForeignTypeReason
OneArgExpected)
    return (CImport src (L lc cconv') safety mh CWrapper)

tcCheckFIType [Scaled Type]
arg_tys Type
res_ty idecl :: ForeignImport GhcRn
idecl@(CImport XCImport GhcRn
src (L EpaLocation
lc CCallConv
cconv) (L EpaLocation
ls Safety
safety) Maybe Header
mh
                                            (CFunction CCallTarget
target))
  | CCallTarget -> Bool
isDynamicTarget CCallTarget
target = do -- Foreign import dynamic
      Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) Backend -> Validity' ExpectedBackends
backendValidityOfCImport
      cconv' <- Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) CCallConv
cconv
      case arg_tys of           -- The first arg must be Ptr or FunPtr
        []                ->
          TcRnMessage -> TcM ()
addErrTc (Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType Maybe ArgOrResult
forall a. Maybe a
Nothing IllegalForeignTypeReason
AtLeastOneArgExpected)
        (Scaled Type
arg1_mult Type
arg1_ty:[Scaled Type]
arg_tys) -> do
          dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
          let curried_res_ty = [Scaled Type] -> Type -> Type
HasDebugCallStack => [Scaled Type] -> Type -> Type
mkScaledFunTys [Scaled Type]
arg_tys Type
res_ty
          checkNoLinearFFI arg1_mult
          check (isFFIDynTy curried_res_ty arg1_ty)
                (TcRnIllegalForeignType (Just Arg))
          checkForeignArgs (isFFIArgumentTy dflags safety) arg_tys
          checkForeignRes nonIOok checkSafe (isFFIImportResultTy dflags) res_ty
      return $ CImport src (L lc cconv') (L ls safety) mh (CFunction target)
  | CCallConv
cconv CCallConv -> CCallConv -> Bool
forall a. Eq a => a -> a -> Bool
== CCallConv
PrimCallConv = do
      dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
      checkTc (xopt LangExt.GHCForeignImportPrim dflags)
              (TcRnForeignImportPrimExtNotSet idecl)
      checkCg (Right idecl) backendValidityOfCImport
      checkCTarget idecl target
      checkTc (playSafe safety)
              (TcRnForeignImportPrimSafeAnn idecl)
      checkForeignArgs (isFFIPrimArgumentTy dflags) arg_tys
      -- prim import result is more liberal, allows (#,,#)
      checkForeignRes nonIOok checkSafe (isFFIPrimResultTy dflags) res_ty
      return (CImport src (L lc cconv) (L ls safety) mh (CFunction target))
  | CCallConv
cconv CCallConv -> CCallConv -> Bool
forall a. Eq a => a -> a -> Bool
== CCallConv
JavaScriptCallConv = do
      cconv' <- Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) CCallConv
cconv
      checkCg (Right idecl) backendValidityOfCImport
      -- leave the rest to the JS backend (at least for now)
      return (CImport src (L lc cconv') (L ls safety) mh (CFunction target))
  | Bool
otherwise = do              -- Normal foreign import
      Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) Backend -> Validity' ExpectedBackends
backendValidityOfCImport
      cconv' <- Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) CCallConv
cconv
      checkCTarget idecl target
      dflags <- getDynFlags
      checkForeignArgs (isFFIArgumentTy dflags safety) arg_tys
      checkForeignRes nonIOok checkSafe (isFFIImportResultTy dflags) res_ty
      checkMissingAmpersand idecl target (map scaledThing arg_tys) res_ty
      case target of
          StaticTarget SourceText
_ CLabelString
_ Maybe Unit
_ Bool
False
           | Bool -> Bool
not ([Scaled Type] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [Scaled Type]
arg_tys) ->
              TcRnMessage -> TcM ()
addErrTc (ForeignImport GhcRn -> TcRnMessage
TcRnForeignFunctionImportAsValue ForeignImport GhcRn
idecl)
          CCallTarget
_ -> () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
      return $ CImport src (L lc cconv') (L ls safety) mh (CFunction target)

-- This makes a convenient place to check
-- that the C identifier is valid for C
checkCTarget :: ForeignImport GhcRn -> CCallTarget -> TcM ()
checkCTarget :: ForeignImport GhcRn -> CCallTarget -> TcM ()
checkCTarget ForeignImport GhcRn
idecl (StaticTarget SourceText
_ CLabelString
str Maybe Unit
_ Bool
_) = do
    Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg (ForeignImport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. b -> Either a b
Right ForeignImport GhcRn
idecl) Backend -> Validity' ExpectedBackends
backendValidityOfCImport
    Bool -> TcRnMessage -> TcM ()
checkTc (CLabelString -> Bool
isCLabelString CLabelString
str) (CLabelString -> TcRnMessage
TcRnInvalidCIdentifier CLabelString
str)

checkCTarget ForeignImport GhcRn
_ CCallTarget
DynamicTarget = String -> TcM ()
forall a. HasCallStack => String -> a
panic String
"checkCTarget DynamicTarget"

checkMissingAmpersand :: ForeignImport GhcRn -> CCallTarget -> [Type] -> Type -> TcM ()
checkMissingAmpersand :: ForeignImport GhcRn -> CCallTarget -> [Type] -> Type -> TcM ()
checkMissingAmpersand ForeignImport GhcRn
_ (StaticTarget SourceText
_ CLabelString
_ Maybe Unit
_ Bool
False) [Type]
_ Type
_ = () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

checkMissingAmpersand ForeignImport GhcRn
idecl CCallTarget
_ [Type]
arg_tys Type
res_ty
  | [Type] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [Type]
arg_tys Bool -> Bool -> Bool
&& Type -> Bool
isFunPtrTy Type
res_ty
  = TcRnMessage -> TcM ()
addDiagnosticTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ ForeignImport GhcRn -> TcRnMessage
TcRnFunPtrImportWithoutAmpersand ForeignImport GhcRn
idecl
  | Bool
otherwise
  = () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

{-
************************************************************************
*                                                                      *
\subsection{Exports}
*                                                                      *
************************************************************************
-}

tcForeignExports :: [LForeignDecl GhcRn]
             -> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignExports :: [LForeignDecl GhcRn]
-> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignExports [LForeignDecl GhcRn]
decls = do
    hooks <- IOEnv (Env TcGblEnv TcLclEnv) Hooks
forall (m :: * -> *). HasHooks m => m Hooks
getHooks
    case tcForeignExportsHook hooks of
        Maybe
  ([LForeignDecl GhcRn]
   -> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt))
Nothing -> [LForeignDecl GhcRn]
-> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignExports' [LForeignDecl GhcRn]
decls
        Just [LForeignDecl GhcRn]
-> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
h  -> [LForeignDecl GhcRn]
-> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
h [LForeignDecl GhcRn]
decls

tcForeignExports' :: [LForeignDecl GhcRn]
             -> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
-- For the (Bag GlobalRdrElt) result,
-- see Note [Newtype constructor usage in foreign declarations]
tcForeignExports' :: [LForeignDecl GhcRn]
-> TcM (LHsBinds GhcTc, [LForeignDecl GhcTc], Bag GlobalRdrElt)
tcForeignExports' [LForeignDecl GhcRn]
decls
  = ((Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
  [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)], Bag GlobalRdrElt)
 -> GenLocated SrcSpanAnnA (ForeignDecl GhcRn)
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
       [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)], Bag GlobalRdrElt))
-> (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
    [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)], Bag GlobalRdrElt)
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)], Bag GlobalRdrElt)
forall (t :: * -> *) (m :: * -> *) b a.
(Foldable t, Monad m) =>
(b -> a -> m b) -> b -> t a -> m b
foldlM (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
 [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)], Bag GlobalRdrElt)
-> GenLocated SrcSpanAnnA (ForeignDecl GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [GenLocated SrcSpanAnnA (ForeignDecl GhcTc)], Bag GlobalRdrElt)
forall {ann}.
(Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
 [GenLocated (EpAnn ann) (ForeignDecl GhcTc)], Bag GlobalRdrElt)
-> GenLocated (EpAnn ann) (ForeignDecl GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [GenLocated (EpAnn ann) (ForeignDecl GhcTc)], Bag GlobalRdrElt)
combine (LHsBinds GhcTc
Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall (idL :: Pass) idR. LHsBindsLR (GhcPass idL) idR
emptyLHsBinds, [], Bag GlobalRdrElt
forall a. Bag a
emptyBag) ((GenLocated SrcSpanAnnA (ForeignDecl GhcRn) -> Bool)
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
-> [GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
forall a. (a -> Bool) -> [a] -> [a]
filter LForeignDecl GhcRn -> Bool
GenLocated SrcSpanAnnA (ForeignDecl GhcRn) -> Bool
forall name. UnXRec name => LForeignDecl name -> Bool
isForeignExport [LForeignDecl GhcRn]
[GenLocated SrcSpanAnnA (ForeignDecl GhcRn)]
decls)
  where
   combine :: (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
 [GenLocated (EpAnn ann) (ForeignDecl GhcTc)], Bag GlobalRdrElt)
-> GenLocated (EpAnn ann) (ForeignDecl GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [GenLocated (EpAnn ann) (ForeignDecl GhcTc)], Bag GlobalRdrElt)
combine (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds, [GenLocated (EpAnn ann) (ForeignDecl GhcTc)]
fs, Bag GlobalRdrElt
gres1) (L EpAnn ann
loc ForeignDecl GhcRn
fe) = do
       (b, f, gres2) <- EpAnn ann
-> TcRn
     (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc), ForeignDecl GhcTc,
      Bag GlobalRdrElt)
-> TcRn
     (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc), ForeignDecl GhcTc,
      Bag GlobalRdrElt)
forall ann a. EpAnn ann -> TcRn a -> TcRn a
setSrcSpanA EpAnn ann
loc (ForeignDecl GhcRn
-> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
tcFExport ForeignDecl GhcRn
fe)
       return (b `consBag` binds, L loc f : fs, gres1 `unionBags` gres2)

tcFExport :: ForeignDecl GhcRn
          -> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
tcFExport :: ForeignDecl GhcRn
-> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
tcFExport fo :: ForeignDecl GhcRn
fo@(ForeignExport { fd_name :: forall pass. ForeignDecl pass -> LIdP pass
fd_name = L SrcSpanAnnN
loc Name
nm, fd_sig_ty :: forall pass. ForeignDecl pass -> LHsSigType pass
fd_sig_ty = LHsSigType GhcRn
hs_ty, fd_fe :: forall pass. ForeignDecl pass -> ForeignExport pass
fd_fe = ForeignExport GhcRn
spec })
  = SDoc
-> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
-> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (ForeignDecl GhcRn -> SDoc
foreignDeclCtxt ForeignDecl GhcRn
fo) (TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
 -> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt))
-> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
-> TcM (LHsBind GhcTc, ForeignDecl GhcTc, Bag GlobalRdrElt)
forall a b. (a -> b) -> a -> b
$ do

    sig_ty <- UserTypeCtxt -> LHsSigType GhcRn -> TcM Type
tcHsSigType (Name -> UserTypeCtxt
ForSigCtxt Name
nm) LHsSigType GhcRn
hs_ty
    rhs <- tcCheckPolyExpr (nlHsVar nm) sig_ty

    (Reduction norm_co norm_sig_ty, gres) <- normaliseFfiType sig_ty

    spec' <- tcCheckFEType norm_sig_ty spec

           -- we're exporting a function, but at a type possibly more
           -- constrained than its declared/inferred type. Hence the need
           -- to create a local binding which will call the exported function
           -- at a particular type (and, maybe, overloading).


    -- We need to give a name to the new top-level binding that
    -- is *stable* (i.e. the compiler won't change it later),
    -- because this name will be referred to by the C code stub.
    id  <- mkStableIdFromName nm sig_ty (locA loc) mkForeignExportOcc
    return ( mkVarBind id rhs
           , ForeignExport { fd_name = L loc id
                           , fd_sig_ty = undefined
                           , fd_e_ext = norm_co
                           , fd_fe = spec' }
           , gres)
tcFExport ForeignDecl GhcRn
d = String
-> SDoc
-> TcRn
     (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc), ForeignDecl GhcTc,
      Bag GlobalRdrElt)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"tcFExport" (ForeignDecl GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr ForeignDecl GhcRn
d)

-- ------------ Checking argument types for foreign export ----------------------

tcCheckFEType :: Type -> ForeignExport GhcRn -> TcM (ForeignExport GhcTc)
tcCheckFEType :: Type -> ForeignExport GhcRn -> TcM (ForeignExport GhcTc)
tcCheckFEType Type
sig_ty edecl :: ForeignExport GhcRn
edecl@(CExport XCExport GhcRn
src (L EpaLocation
l (CExportStatic SourceText
esrc CLabelString
str CCallConv
cconv))) = do
    Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg (ForeignExport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. a -> Either a b
Left ForeignExport GhcRn
edecl) Backend -> Validity' ExpectedBackends
backendValidityOfCExport
    Bool -> TcRnMessage -> TcM ()
checkTc (CLabelString -> Bool
isCLabelString CLabelString
str) (CLabelString -> TcRnMessage
TcRnInvalidCIdentifier CLabelString
str)
    cconv' <- Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv (ForeignExport GhcRn
-> Either (ForeignExport GhcRn) (ForeignImport GhcRn)
forall a b. a -> Either a b
Left ForeignExport GhcRn
edecl) CCallConv
cconv
    checkForeignArgs isFFIExternalTy arg_tys
    checkForeignRes nonIOok noCheckSafe isFFIExportResultTy res_ty
    return (CExport src (L l (CExportStatic esrc str cconv')))
  where
      -- Drop the foralls before inspecting
      -- the structure of the foreign type.
    ([Scaled Type]
arg_tys, Type
res_ty) = Type -> ([Scaled Type], Type)
tcSplitFunTys (Type -> Type
dropForAlls Type
sig_ty)

{-
************************************************************************
*                                                                      *
\subsection{Miscellaneous}
*                                                                      *
************************************************************************
-}

------------ Checking argument types for foreign import ----------------------
checkForeignArgs :: (Type -> Validity' IllegalForeignTypeReason) -> [Scaled Type] -> TcM ()
checkForeignArgs :: (Type -> Validity' IllegalForeignTypeReason)
-> [Scaled Type] -> TcM ()
checkForeignArgs Type -> Validity' IllegalForeignTypeReason
pred [Scaled Type]
tys = (Scaled Type -> TcM ()) -> [Scaled Type] -> TcM ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ Scaled Type -> TcM ()
go [Scaled Type]
tys
  where
    go :: Scaled Type -> TcM ()
go (Scaled Type
mult Type
ty) = Type -> TcM ()
checkNoLinearFFI Type
mult TcM () -> TcM () -> TcM ()
forall a b.
IOEnv (Env TcGblEnv TcLclEnv) a
-> IOEnv (Env TcGblEnv TcLclEnv) b
-> IOEnv (Env TcGblEnv TcLclEnv) b
forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>>
                          Validity' IllegalForeignTypeReason
-> (IllegalForeignTypeReason -> TcRnMessage) -> TcM ()
check (Type -> Validity' IllegalForeignTypeReason
pred Type
ty) (Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Arg))

checkNoLinearFFI :: Mult -> TcM ()  -- No linear types in FFI (#18472)
checkNoLinearFFI :: Type -> TcM ()
checkNoLinearFFI Type
ManyTy = () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
checkNoLinearFFI Type
_      = TcRnMessage -> TcM ()
addErrTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Arg)
                                   IllegalForeignTypeReason
LinearTypesNotAllowed

------------ Checking result types for foreign calls ----------------------
-- | Check that the type has the form
--    (IO t) or (t) , and that t satisfies the given predicate.
-- When calling this function, any newtype wrappers (should) have been
-- already dealt with by normaliseFfiType.
--
-- We also check that the Safe Haskell condition of FFI imports having
-- results in the IO monad holds.
--
checkForeignRes :: Bool -> Bool -> (Type -> Validity' IllegalForeignTypeReason) -> Type -> TcM ()
checkForeignRes :: Bool
-> Bool
-> (Type -> Validity' IllegalForeignTypeReason)
-> Type
-> TcM ()
checkForeignRes Bool
non_io_result_ok Bool
check_safe Type -> Validity' IllegalForeignTypeReason
pred_res_ty Type
ty
  | Just (TyCon
_, Type
res_ty) <- Type -> Maybe (TyCon, Type)
tcSplitIOType_maybe Type
ty
  =     -- Got an IO result type, that's always fine!
     Validity' IllegalForeignTypeReason
-> (IllegalForeignTypeReason -> TcRnMessage) -> TcM ()
check (Type -> Validity' IllegalForeignTypeReason
pred_res_ty Type
res_ty)
           (Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Result))

  -- We disallow nested foralls in foreign types
  -- (at least, for the time being). See #16702.
  | Type -> Bool
isForAllTy Type
ty
  = TcRnMessage -> TcM ()
addErrTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Result) IllegalForeignTypeReason
UnexpectedNestedForall

  -- Case for non-IO result type with FFI Import
  | Bool -> Bool
not Bool
non_io_result_ok
  = TcRnMessage -> TcM ()
addErrTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Result) IllegalForeignTypeReason
IOResultExpected

  | Bool
otherwise
  = do { dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
       ; case pred_res_ty ty of
                -- Handle normal typecheck fail, we want to handle this first and
                -- only report safe haskell errors if the normal type check is OK.
           NotValid IllegalForeignTypeReason
msg -> TcRnMessage -> TcM ()
addErrTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Result) IllegalForeignTypeReason
msg

           -- handle safe infer fail
           Validity' IllegalForeignTypeReason
_ | Bool
check_safe Bool -> Bool -> Bool
&& DynFlags -> Bool
safeInferOn DynFlags
dflags
               -> Messages TcRnMessage -> TcM ()
recordUnsafeInfer Messages TcRnMessage
forall e. Messages e
emptyMessages

           -- handle safe language typecheck fail
           Validity' IllegalForeignTypeReason
_ | Bool
check_safe Bool -> Bool -> Bool
&& DynFlags -> Bool
safeLanguageOn DynFlags
dflags
               -> TcRnMessage -> TcM ()
addErrTc (Maybe ArgOrResult -> IllegalForeignTypeReason -> TcRnMessage
TcRnIllegalForeignType (ArgOrResult -> Maybe ArgOrResult
forall a. a -> Maybe a
Just ArgOrResult
Result) IllegalForeignTypeReason
SafeHaskellMustBeInIO)

           -- success! non-IO return is fine
           Validity' IllegalForeignTypeReason
_ -> () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return () }

nonIOok, mustBeIO :: Bool
nonIOok :: Bool
nonIOok  = Bool
True
mustBeIO :: Bool
mustBeIO = Bool
False

checkSafe, noCheckSafe :: Bool
checkSafe :: Bool
checkSafe   = Bool
True
noCheckSafe :: Bool
noCheckSafe = Bool
False

checkCg :: Either (ForeignExport GhcRn) (ForeignImport GhcRn)
        -> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg :: Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> (Backend -> Validity' ExpectedBackends) -> TcM ()
checkCg Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl Backend -> Validity' ExpectedBackends
check = do
    dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
    let bcknd = DynFlags -> Backend
backend DynFlags
dflags
    case check bcknd of
      Validity' ExpectedBackends
IsValid -> () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
      NotValid ExpectedBackends
expectedBcknds ->
        TcRnMessage -> TcM ()
addErrTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> Backend -> ExpectedBackends -> TcRnMessage
TcRnIllegalForeignDeclBackend Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl Backend
bcknd ExpectedBackends
expectedBcknds

-- Calling conventions

checkCConv :: Either (ForeignExport GhcRn) (ForeignImport GhcRn)
           -> CCallConv -> TcM CCallConv
checkCConv :: Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> CCallConv -> TcM CCallConv
checkCConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
_ CCallConv
CCallConv    = CCallConv -> TcM CCallConv
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return CCallConv
CCallConv
checkCConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
_ CCallConv
CApiConv     = CCallConv -> TcM CCallConv
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return CCallConv
CApiConv
checkCConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl CCallConv
StdCallConv = do
  dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
  let platform = DynFlags -> Platform
targetPlatform DynFlags
dflags
  if platformArch platform == ArchX86
      then return StdCallConv
      else do -- This is a warning, not an error. see #3336
              let msg = Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> UnsupportedCallConvention -> TcRnMessage
TcRnUnsupportedCallConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl UnsupportedCallConvention
StdCallConvUnsupported
              addDiagnosticTc msg
              return CCallConv
checkCConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl CCallConv
PrimCallConv = do
  TcRnMessage -> TcM ()
addErrTc (TcRnMessage -> TcM ()) -> TcRnMessage -> TcM ()
forall a b. (a -> b) -> a -> b
$ Either (ForeignExport GhcRn) (ForeignImport GhcRn)
-> UnsupportedCallConvention -> TcRnMessage
TcRnUnsupportedCallConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl UnsupportedCallConvention
PrimCallConvUnsupported
  CCallConv -> TcM CCallConv
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return CCallConv
PrimCallConv
checkCConv Either (ForeignExport GhcRn) (ForeignImport GhcRn)
decl CCallConv
JavaScriptCallConv = do
  dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
  if platformArch (targetPlatform dflags) `elem` [ ArchJavaScript, ArchWasm32 ]
      then return JavaScriptCallConv
      else do
        addErrTc $ TcRnUnsupportedCallConv decl JavaScriptCallConvUnsupported
        return JavaScriptCallConv

-- Warnings

check :: Validity' IllegalForeignTypeReason
      -> (IllegalForeignTypeReason -> TcRnMessage)
      -> TcM ()
check :: Validity' IllegalForeignTypeReason
-> (IllegalForeignTypeReason -> TcRnMessage) -> TcM ()
check Validity' IllegalForeignTypeReason
IsValid IllegalForeignTypeReason -> TcRnMessage
_                   = () -> TcM ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
check (NotValid IllegalForeignTypeReason
reason) IllegalForeignTypeReason -> TcRnMessage
mkMessage = TcRnMessage -> TcM ()
addErrTc (IllegalForeignTypeReason -> TcRnMessage
mkMessage IllegalForeignTypeReason
reason)

foreignDeclCtxt :: ForeignDecl GhcRn -> SDoc
foreignDeclCtxt :: ForeignDecl GhcRn -> SDoc
foreignDeclCtxt ForeignDecl GhcRn
fo
  = SDoc -> Int -> SDoc -> SDoc
hang (String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"When checking declaration:")
       Int
2 (ForeignDecl GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr ForeignDecl GhcRn
fo)


{- Predicates on Types used in this module -}

-- | Reason why a type in an FFI signature is invalid

isFFIArgumentTy :: DynFlags -> Safety -> Type -> Validity' IllegalForeignTypeReason
-- Checks for valid argument type for a 'foreign import'
isFFIArgumentTy :: DynFlags -> Safety -> Type -> Validity' IllegalForeignTypeReason
isFFIArgumentTy DynFlags
dflags Safety
safety Type
ty
   = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon (DynFlags
-> Safety -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalOutgoingTyCon DynFlags
dflags Safety
safety) Type
ty

isFFIExternalTy :: Type -> Validity' IllegalForeignTypeReason
-- Types that are allowed as arguments of a 'foreign export'
isFFIExternalTy :: Type -> Validity' IllegalForeignTypeReason
isFFIExternalTy Type
ty = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon TyCon -> Validity' TypeCannotBeMarshaledReason
legalFEArgTyCon Type
ty

isFFIImportResultTy :: DynFlags -> Type -> Validity' IllegalForeignTypeReason
isFFIImportResultTy :: DynFlags -> Type -> Validity' IllegalForeignTypeReason
isFFIImportResultTy DynFlags
dflags Type
ty
  = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon (DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIResultTyCon DynFlags
dflags) Type
ty

isFFIExportResultTy :: Type -> Validity' IllegalForeignTypeReason
isFFIExportResultTy :: Type -> Validity' IllegalForeignTypeReason
isFFIExportResultTy Type
ty = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon TyCon -> Validity' TypeCannotBeMarshaledReason
legalFEResultTyCon Type
ty

isFFIDynTy :: Type -> Type -> Validity' IllegalForeignTypeReason
-- The type in a foreign import dynamic must be Ptr, FunPtr, or a newtype of
-- either, and the wrapped function type must be equal to the given type.
-- We assume that all types have been run through normaliseFfiType, so we don't
-- need to worry about expanding newtypes here.
isFFIDynTy :: Type -> Type -> Validity' IllegalForeignTypeReason
isFFIDynTy Type
expected Type
ty
    -- Note [Foreign import dynamic]
    -- In the example below, expected would be 'CInt -> IO ()', while ty would
    -- be 'FunPtr (CDouble -> IO ())'.
    | Just (TyCon
tc, [Type
ty']) <- HasDebugCallStack => Type -> Maybe (TyCon, [Type])
Type -> Maybe (TyCon, [Type])
splitTyConApp_maybe Type
ty
    , TyCon -> Unique
tyConUnique TyCon
tc Unique -> [Unique] -> Bool
forall a. Eq a => a -> [a] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [Unique
ptrTyConKey, Unique
funPtrTyConKey]
    , Type -> Type -> Bool
eqType Type
ty' Type
expected
    = Validity' IllegalForeignTypeReason
forall a. Validity' a
IsValid
    | Bool
otherwise
    = IllegalForeignTypeReason -> Validity' IllegalForeignTypeReason
forall a. a -> Validity' a
NotValid (Type -> Type -> IllegalForeignTypeReason
ForeignDynNotPtr Type
expected Type
ty)

isFFILabelTy :: Type -> Validity' IllegalForeignTypeReason
-- The type of a foreign label must be Ptr, FunPtr, or a newtype of either.
isFFILabelTy :: Type -> Validity' IllegalForeignTypeReason
isFFILabelTy Type
ty = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon TyCon -> Validity' TypeCannotBeMarshaledReason
forall {a}.
Uniquable a =>
a -> Validity' TypeCannotBeMarshaledReason
ok Type
ty
  where
    ok :: a -> Validity' TypeCannotBeMarshaledReason
ok a
tc | a
tc a -> Unique -> Bool
forall a. Uniquable a => a -> Unique -> Bool
`hasKey` Unique
funPtrTyConKey Bool -> Bool -> Bool
|| a
tc a -> Unique -> Bool
forall a. Uniquable a => a -> Unique -> Bool
`hasKey` Unique
ptrTyConKey
          = Validity' TypeCannotBeMarshaledReason
forall a. Validity' a
IsValid
          | Bool
otherwise
          = TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid TypeCannotBeMarshaledReason
ForeignLabelNotAPtr

-- | Check validity for a type of the form @Any :: k@.
--
-- This function returns:
--
--  - @Just IsValid@ for @Any :: Type@ and @Any :: UnliftedType@,
--  - @Just (NotValid ..)@ for @Any :: k@ if @k@ is not a kind of boxed types,
--  - @Nothing@ if the type is not @Any@.
checkAnyTy :: Type -> Maybe (Validity' IllegalForeignTypeReason)
checkAnyTy :: Type -> Maybe (Validity' IllegalForeignTypeReason)
checkAnyTy Type
ty
  | Just Type
ki <- Type -> Maybe Type
anyTy_maybe Type
ty
  = Validity' IllegalForeignTypeReason
-> Maybe (Validity' IllegalForeignTypeReason)
forall a. a -> Maybe a
Just (Validity' IllegalForeignTypeReason
 -> Maybe (Validity' IllegalForeignTypeReason))
-> Validity' IllegalForeignTypeReason
-> Maybe (Validity' IllegalForeignTypeReason)
forall a b. (a -> b) -> a -> b
$
      if Maybe Levity -> Bool
forall a. Maybe a -> Bool
isJust (Maybe Levity -> Bool) -> Maybe Levity -> Bool
forall a b. (a -> b) -> a -> b
$ Type -> Maybe Levity
kindBoxedRepLevity_maybe Type
ki
      then Validity' IllegalForeignTypeReason
forall a. Validity' a
IsValid
      -- NB: don't allow things like @Any :: TYPE IntRep@, as per #21305.
      else IllegalForeignTypeReason -> Validity' IllegalForeignTypeReason
forall a. a -> Validity' a
NotValid (Type -> TypeCannotBeMarshaledReason -> IllegalForeignTypeReason
TypeCannotBeMarshaled Type
ty TypeCannotBeMarshaledReason
NotBoxedKindAny)
  | Bool
otherwise
  = Maybe (Validity' IllegalForeignTypeReason)
forall a. Maybe a
Nothing

isFFIPrimArgumentTy :: DynFlags -> Type -> Validity' IllegalForeignTypeReason
-- Checks for valid argument type for a 'foreign import prim'
-- Currently they must all be simple unlifted types, or Any (at kind Type or UnliftedType),
-- which can be used to pass the address to a Haskell object on the heap to
-- the foreign function.
isFFIPrimArgumentTy :: DynFlags -> Type -> Validity' IllegalForeignTypeReason
isFFIPrimArgumentTy DynFlags
dflags Type
ty
  | Just Validity' IllegalForeignTypeReason
validity <- Type -> Maybe (Validity' IllegalForeignTypeReason)
checkAnyTy Type
ty
  = Validity' IllegalForeignTypeReason
validity
  | Bool
otherwise
  = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon (DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIPrimArgTyCon DynFlags
dflags) Type
ty

isFFIPrimResultTy :: DynFlags -> Type -> Validity' IllegalForeignTypeReason
-- Checks for valid result type for a 'foreign import prim' Currently
-- it must be an unlifted type, including unboxed tuples, unboxed
-- sums, or the well-known type Any (at kind Type or UnliftedType).
isFFIPrimResultTy :: DynFlags -> Type -> Validity' IllegalForeignTypeReason
isFFIPrimResultTy DynFlags
dflags Type
ty
  | Just Validity' IllegalForeignTypeReason
validity <- Type -> Maybe (Validity' IllegalForeignTypeReason)
checkAnyTy Type
ty
  = Validity' IllegalForeignTypeReason
validity
  | Bool
otherwise
  = (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon (DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIPrimResultTyCon DynFlags
dflags) Type
ty

isFunPtrTy :: Type -> Bool
isFunPtrTy :: Type -> Bool
isFunPtrTy Type
ty
  | Just (TyCon
tc, [Type
_]) <- HasDebugCallStack => Type -> Maybe (TyCon, [Type])
Type -> Maybe (TyCon, [Type])
splitTyConApp_maybe Type
ty
  = TyCon
tc TyCon -> Unique -> Bool
forall a. Uniquable a => a -> Unique -> Bool
`hasKey` Unique
funPtrTyConKey
  | Bool
otherwise
  = Bool
False

-- normaliseFfiType gets run before checkRepTyCon, so we don't
-- need to worry about looking through newtypes or type functions
-- here; that's already been taken care of.
checkRepTyCon
  :: (TyCon -> Validity' TypeCannotBeMarshaledReason)
  -> Type
  -> Validity' IllegalForeignTypeReason
checkRepTyCon :: (TyCon -> Validity' TypeCannotBeMarshaledReason)
-> Type -> Validity' IllegalForeignTypeReason
checkRepTyCon TyCon -> Validity' TypeCannotBeMarshaledReason
check_tc Type
ty
  = (TypeCannotBeMarshaledReason -> IllegalForeignTypeReason)
-> Validity' TypeCannotBeMarshaledReason
-> Validity' IllegalForeignTypeReason
forall a b. (a -> b) -> Validity' a -> Validity' b
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (Type -> TypeCannotBeMarshaledReason -> IllegalForeignTypeReason
TypeCannotBeMarshaled Type
ty) (Validity' TypeCannotBeMarshaledReason
 -> Validity' IllegalForeignTypeReason)
-> Validity' TypeCannotBeMarshaledReason
-> Validity' IllegalForeignTypeReason
forall a b. (a -> b) -> a -> b
$ case HasDebugCallStack => Type -> Maybe (TyCon, [Type])
Type -> Maybe (TyCon, [Type])
splitTyConApp_maybe Type
ty of
      Just (TyCon
tc, [Type]
tys)
        | TyCon -> Bool
isNewTyCon TyCon
tc -> TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid (TyCon -> [Type] -> TypeCannotBeMarshaledReason
mk_nt_reason TyCon
tc [Type]
tys)
        | Bool
otherwise     -> TyCon -> Validity' TypeCannotBeMarshaledReason
check_tc TyCon
tc
      Maybe (TyCon, [Type])
Nothing -> TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid TypeCannotBeMarshaledReason
NotADataType
  where
    mk_nt_reason :: TyCon -> [Type] -> TypeCannotBeMarshaledReason
mk_nt_reason TyCon
tc [Type]
tys = TyCon -> [Type] -> TypeCannotBeMarshaledReason
NewtypeDataConNotInScope TyCon
tc [Type]
tys

{-
Note [Foreign import dynamic]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A dynamic stub must be of the form 'FunPtr ft -> ft' where ft is any foreign
type.  Similarly, a wrapper stub must be of the form 'ft -> IO (FunPtr ft)'.

We use isFFIDynTy to check whether a signature is well-formed. For example,
given a (illegal) declaration like:

foreign import ccall "dynamic"
  foo :: FunPtr (CDouble -> IO ()) -> CInt -> IO ()

isFFIDynTy will compare the 'FunPtr' type 'CDouble -> IO ()' with the curried
result type 'CInt -> IO ()', and return False, as they are not equal.


----------------------------------------------
These chaps do the work; they are not exported
----------------------------------------------
-}

legalFEArgTyCon :: TyCon -> Validity' TypeCannotBeMarshaledReason
legalFEArgTyCon :: TyCon -> Validity' TypeCannotBeMarshaledReason
legalFEArgTyCon TyCon
tc
  -- It's illegal to make foreign exports that take unboxed
  -- arguments.  The RTS API currently can't invoke such things.  --SDM 7/2000
  = TyCon -> Validity' TypeCannotBeMarshaledReason
boxedMarshalableTyCon TyCon
tc

legalFIResultTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIResultTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIResultTyCon DynFlags
dflags TyCon
tc
  | TyCon
tc TyCon -> TyCon -> Bool
forall a. Eq a => a -> a -> Bool
== TyCon
unitTyCon         = Validity' TypeCannotBeMarshaledReason
forall a. Validity' a
IsValid
  | Bool
otherwise               = DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
marshalableTyCon DynFlags
dflags TyCon
tc

legalFEResultTyCon :: TyCon -> Validity' TypeCannotBeMarshaledReason
legalFEResultTyCon :: TyCon -> Validity' TypeCannotBeMarshaledReason
legalFEResultTyCon TyCon
tc
  | TyCon
tc TyCon -> TyCon -> Bool
forall a. Eq a => a -> a -> Bool
== TyCon
unitTyCon         = Validity' TypeCannotBeMarshaledReason
forall a. Validity' a
IsValid
  | Bool
otherwise               = TyCon -> Validity' TypeCannotBeMarshaledReason
boxedMarshalableTyCon TyCon
tc

legalOutgoingTyCon :: DynFlags -> Safety -> TyCon -> Validity' TypeCannotBeMarshaledReason
-- Checks validity of types going from Haskell -> external world
legalOutgoingTyCon :: DynFlags
-> Safety -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalOutgoingTyCon DynFlags
dflags Safety
_ TyCon
tc
  = DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
marshalableTyCon DynFlags
dflags TyCon
tc

-- Check for marshalability of a primitive type.
-- We exclude lifted types such as RealWorld and TYPE.
-- They can technically appear in types, e.g.
-- f :: RealWorld -> TYPE LiftedRep -> RealWorld
-- f x _ = x
-- but there are no values of type RealWorld or TYPE LiftedRep,
-- so it doesn't make sense to use them in FFI.
marshalablePrimTyCon :: TyCon -> Bool
marshalablePrimTyCon :: TyCon -> Bool
marshalablePrimTyCon TyCon
tc = TyCon -> Bool
isPrimTyCon TyCon
tc Bool -> Bool -> Bool
&& Bool -> Bool
not (Type -> Bool
isLiftedTypeKind (TyCon -> Type
tyConResKind TyCon
tc))

marshalableTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
marshalableTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
marshalableTyCon DynFlags
dflags TyCon
tc
  | TyCon -> Bool
marshalablePrimTyCon TyCon
tc
  = DynFlags -> Validity' TypeCannotBeMarshaledReason
validIfUnliftedFFITypes DynFlags
dflags
  | Bool
otherwise
  = TyCon -> Validity' TypeCannotBeMarshaledReason
boxedMarshalableTyCon TyCon
tc

boxedMarshalableTyCon :: TyCon -> Validity' TypeCannotBeMarshaledReason
boxedMarshalableTyCon :: TyCon -> Validity' TypeCannotBeMarshaledReason
boxedMarshalableTyCon TyCon
tc
   | TyCon -> [Unique] -> Bool
forall a. Uniquable a => a -> [Unique] -> Bool
anyOfUnique TyCon
tc [ Unique
intTyConKey, Unique
int8TyConKey, Unique
int16TyConKey
                    , Unique
int32TyConKey, Unique
int64TyConKey
                    , Unique
wordTyConKey, Unique
word8TyConKey, Unique
word16TyConKey
                    , Unique
word32TyConKey, Unique
word64TyConKey
                    , Unique
floatTyConKey, Unique
doubleTyConKey
                    , Unique
ptrTyConKey, Unique
funPtrTyConKey
                    , Unique
charTyConKey
                    , Unique
stablePtrTyConKey
                    , Unique
boolTyConKey
                    , Unique
jsvalTyConKey
                    ]
  = Validity' TypeCannotBeMarshaledReason
forall a. Validity' a
IsValid

  | Bool
otherwise = TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid TypeCannotBeMarshaledReason
NotABoxedMarshalableTyCon

legalFIPrimArgTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
-- Check args of 'foreign import prim', only allow simple unlifted types.
legalFIPrimArgTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIPrimArgTyCon DynFlags
dflags TyCon
tc
  | TyCon -> Bool
marshalablePrimTyCon TyCon
tc
  = DynFlags -> Validity' TypeCannotBeMarshaledReason
validIfUnliftedFFITypes DynFlags
dflags
  | Bool
otherwise
  = TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid TypeCannotBeMarshaledReason
NotSimpleUnliftedType

legalFIPrimResultTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
-- Check result type of 'foreign import prim'. Allow simple unlifted
-- types and also unboxed tuple and sum result types.
legalFIPrimResultTyCon :: DynFlags -> TyCon -> Validity' TypeCannotBeMarshaledReason
legalFIPrimResultTyCon DynFlags
dflags TyCon
tc
  | TyCon -> Bool
marshalablePrimTyCon TyCon
tc
  = DynFlags -> Validity' TypeCannotBeMarshaledReason
validIfUnliftedFFITypes DynFlags
dflags

  | TyCon -> Bool
isUnboxedTupleTyCon TyCon
tc Bool -> Bool -> Bool
|| TyCon -> Bool
isUnboxedSumTyCon TyCon
tc
  = DynFlags -> Validity' TypeCannotBeMarshaledReason
validIfUnliftedFFITypes DynFlags
dflags

  | Bool
otherwise
  = TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid (TypeCannotBeMarshaledReason
 -> Validity' TypeCannotBeMarshaledReason)
-> TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a b. (a -> b) -> a -> b
$ TypeCannotBeMarshaledReason
NotSimpleUnliftedType

validIfUnliftedFFITypes :: DynFlags -> Validity' TypeCannotBeMarshaledReason
validIfUnliftedFFITypes :: DynFlags -> Validity' TypeCannotBeMarshaledReason
validIfUnliftedFFITypes DynFlags
dflags
  | Extension -> DynFlags -> Bool
xopt Extension
LangExt.UnliftedFFITypes DynFlags
dflags =  Validity' TypeCannotBeMarshaledReason
forall a. Validity' a
IsValid
  | Bool
otherwise = TypeCannotBeMarshaledReason
-> Validity' TypeCannotBeMarshaledReason
forall a. a -> Validity' a
NotValid TypeCannotBeMarshaledReason
UnliftedFFITypesNeeded