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|
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
-- | Handling of JavaScript foreign imports/exports
module GHC.HsToCore.Foreign.JavaScript
( dsJsImport
, dsJsFExport
, dsJsFExportDynamic
)
where
import GHC.Prelude
import GHC.Platform
import GHC.Hs
import GHC.HsToCore.Monad
import GHC.HsToCore.Foreign.Call
import GHC.HsToCore.Foreign.Prim
import GHC.HsToCore.Foreign.Utils
import GHC.HsToCore.Utils
import GHC.Core
import GHC.Core.Make
import GHC.Core.Utils
import GHC.Core.DataCon
import GHC.Core.Unfold.Make
import GHC.Core.Type
import GHC.Core.TyCon
import GHC.Core.Coercion
import GHC.Core.Multiplicity
import GHC.Types.Id
import GHC.Types.Id.Make
import GHC.Types.Literal
import GHC.Types.ForeignStubs
import GHC.Types.SourceText
import GHC.Types.Name
import GHC.Types.RepType
import GHC.Types.ForeignCall
import GHC.Types.Basic
import GHC.Types.Unique
import GHC.Unit.Module
import GHC.Tc.Utils.TcType
import GHC.Cmm.Expr
import GHC.Cmm.Utils
import GHC.JS.Ppr
import GHC.Driver.Session
import GHC.Driver.Config
import GHC.Builtin.Types
import GHC.Builtin.Types.Prim
import GHC.Builtin.Names
import GHC.Data.FastString
import GHC.Data.Pair
import GHC.Data.Maybe
import GHC.Utils.Outputable
import GHC.Utils.Panic
import GHC.Utils.Encoding
dsJsFExport
:: Id -- Either the exported Id,
-- or the foreign-export-dynamic constructor
-> Coercion -- Coercion between the Haskell type callable
-- from C, and its representation type
-> CLabelString -- The name to export to C land
-> CCallConv
-> Bool -- True => foreign export dynamic
-- so invoke IO action that's hanging off
-- the first argument's stable pointer
-> DsM ( CHeader -- contents of Module_stub.h
, CStub -- contents of Module_stub.c
, String -- string describing type to pass to createAdj.
, Int -- size of args to stub function
)
dsJsFExport fn_id co ext_name cconv isDyn = do
let
ty = pSnd $ coercionKind co
(_tvs,sans_foralls) = tcSplitForAllTyVars ty
(fe_arg_tys', orig_res_ty) = tcSplitFunTys sans_foralls
-- We must use tcSplits here, because we want to see
-- the (IO t) in the corner of the type!
fe_arg_tys | isDyn = tail fe_arg_tys'
| otherwise = fe_arg_tys'
-- Look at the result type of the exported function, orig_res_ty
-- If it's IO t, return (t, True)
-- If it's plain t, return (t, False)
(res_ty, is_IO_res_ty) = case tcSplitIOType_maybe orig_res_ty of
-- The function already returns IO t
Just (_ioTyCon, res_ty) -> (res_ty, True)
-- The function returns t
Nothing -> (orig_res_ty, False)
platform <- targetPlatform <$> getDynFlags
return $
mkFExportJSBits platform ext_name
(if isDyn then Nothing else Just fn_id)
(map scaledThing fe_arg_tys) res_ty is_IO_res_ty cconv
mkFExportJSBits
:: Platform
-> FastString
-> Maybe Id -- Just==static, Nothing==dynamic
-> [Type]
-> Type
-> Bool -- True <=> returns an IO type
-> CCallConv
-> (CHeader,
CStub,
String, -- the argument reps
Int -- total size of arguments
)
mkFExportJSBits platform c_nm maybe_target arg_htys res_hty is_IO_res_ty _cconv
= (header_bits, js_bits, type_string,
sum [ widthInBytes (typeWidth rep) | (_,_,_,rep) <- arg_info] -- all the args
-- NB. the calculation here isn't strictly speaking correct.
-- We have a primitive Haskell type (eg. Int#, Double#), and
-- we want to know the size, when passed on the C stack, of
-- the associated C type (eg. HsInt, HsDouble). We don't have
-- this information to hand, but we know what GHC's conventions
-- are for passing around the primitive Haskell types, so we
-- use that instead. I hope the two coincide --SDM
)
where
-- list the arguments to the JS function
arg_info :: [(SDoc, -- arg name
SDoc, -- C type
Type, -- Haskell type
CmmType)] -- the CmmType
arg_info = [ let stg_type = showStgType ty in
(arg_cname n stg_type,
stg_type,
ty,
typeCmmType platform (getPrimTyOf ty))
| (ty,n) <- zip arg_htys [1::Int ..] ]
arg_cname n _stg_ty = text ('a':show n)
type_string = primTyDescChar platform res_hty : arg_type_string
arg_type_string = [primTyDescChar platform ty | (_,_,ty,_) <- arg_info]
-- stuff to do with the return type of the JS function
res_hty_is_unit = res_hty `eqType` unitTy -- Look through any newtypes
unboxResType | res_hty_is_unit = text "h$rts_getUnit"
| otherwise = unpackHObj res_hty
header_bits = maybe mempty idTag maybe_target
idTag i = let (tag, u) = unpkUnique (getUnique i)
in CHeader (char tag <> int u)
fun_args
| null arg_info = empty -- text "void"
| otherwise = hsep $ punctuate comma
$ map (\(nm,_ty,_,_) -> nm) arg_info
fun_proto
= text "async" <+>
text "function" <+>
(if isNothing maybe_target
then text "h$" <> ftext c_nm
else ftext c_nm) <>
parens fun_args
fun_export
= case maybe_target of
Just hs_fn | Just m <- nameModule_maybe (getName hs_fn) ->
text "h$foreignExport" <>
parens (
ftext c_nm <> comma <>
strlit (unitIdFS (moduleUnitId m)) <> comma <>
strlit (moduleNameFS (moduleName m)) <> comma <>
strlit c_nm <> comma <>
strlit (mkFastString type_string)
) <> semi
_ -> empty
strlit xs = docToSDoc (pprStringLit xs)
-- the target which will form the root of what we ask rts_evalIO to run
the_cfun
= case maybe_target of
Nothing -> text "h$deRefStablePtr(the_stableptr)"
Just hs_fn -> idClosureText hs_fn
-- the expression we give to rts_eval
expr_to_run :: SDoc
expr_to_run
= foldl appArg the_cfun arg_info
where
appArg acc (arg_cname, _, arg_hty, _)
= text "h$rts_apply"
<> parens (acc <> comma <> mkHObj arg_hty <> parens arg_cname)
-- finally, the whole darn thing
js_bits = CStub { getCStub = js_sdoc
, getInitializers = mempty
, getFinalizers = mempty
}
where js_sdoc = space
$$ fun_proto
$$ vcat
[ lbrace
, text "return"
<+> text "await"
<+> text "h$rts_eval"
<> parens ((if is_IO_res_ty
then expr_to_run
else text "h$rts_toIO" <> parens expr_to_run)
<> comma <+> unboxResType)
<> semi
, rbrace
]
$$ fun_export
idClosureText :: Id -> SDoc
idClosureText i
| isExportedId i
, name <- getName i
, Just m <- nameModule_maybe name
= let str = renderWithContext defaultSDocContext (pprFullName m (localiseName name))
in text "h$" <> text (zEncodeString str)
| otherwise
= panic "idClosureText: unknown module"
-- | Desugaring of JavaScript foreign imports
dsJsImport
:: Id
-> Coercion
-> CImportSpec
-> CCallConv
-> Safety
-> Maybe Header
-> DsM ([Binding], CHeader, CStub)
dsJsImport id co (CLabel cid) cconv _ _ = do
let ty = pFst $ coercionKind co
fod = case tyConAppTyCon_maybe (dropForAlls ty) of
Just tycon
| tyConUnique tycon == funPtrTyConKey ->
IsFunction
_ -> IsData
(_resTy, foRhs) <- jsResultWrapper ty
-- ASSERT(fromJust resTy `eqType` addrPrimTy) -- typechecker ensures this
let rhs = foRhs (Lit (LitLabel cid stdcall_info fod))
rhs' = Cast rhs co
stdcall_info = fun_type_arg_stdcall_info cconv ty
return ([(id, rhs')], mempty, mempty)
dsJsImport id co (CFunction target) cconv@PrimCallConv safety _
= dsPrimCall id co (CCall (CCallSpec target cconv safety))
dsJsImport id co (CFunction target) cconv safety mHeader
= dsJsCall id co (CCall (CCallSpec target cconv safety)) mHeader
dsJsImport id co CWrapper cconv _ _
= dsJsFExportDynamic id co cconv
-- fixme work in progress
-- FIXME (Sylvain 2022-03): possibility of code sharing with dsFExportDynamic?
-- Lot of duplication
dsJsFExportDynamic :: Id
-> Coercion
-> CCallConv
-> DsM ([Binding], CHeader, CStub)
dsJsFExportDynamic id co0 cconv = do
let
ty = pFst (coercionKind co0)
(tvs,sans_foralls) = tcSplitForAllTyVars ty
([Scaled arg_mult arg_ty], fn_res_ty) = tcSplitFunTys sans_foralls
(io_tc, res_ty) = expectJust "dsJsFExportDynamic: IO type expected"
-- Must have an IO type; hence Just
$ tcSplitIOType_maybe fn_res_ty
mod <- getModule
platform <- targetPlatform <$> getDynFlags
let fe_nm = mkFastString $ zEncodeString
("h$" ++ moduleStableString mod ++ "$" ++ toJsName id)
-- Construct the label based on the passed id, don't use names
-- depending on Unique. See #13807 and Note [Unique Determinism].
cback <- newSysLocalDs arg_mult arg_ty
newStablePtrId <- dsLookupGlobalId newStablePtrName
stable_ptr_tycon <- dsLookupTyCon stablePtrTyConName
let
stable_ptr_ty = mkTyConApp stable_ptr_tycon [arg_ty]
export_ty = mkVisFunTyMany stable_ptr_ty arg_ty
bindIOId <- dsLookupGlobalId bindIOName
stbl_value <- newSysLocalDs ManyTy stable_ptr_ty
(h_code, c_code, typestring, args_size) <- dsJsFExport id (mkRepReflCo export_ty) fe_nm cconv True
let
{-
The arguments to the external function which will
create a little bit of (template) code on the fly
for allowing the (stable pointed) Haskell closure
to be entered using an external calling convention
(stdcall, ccall).
-}
adj_args = [ mkIntLit platform (toInteger (ccallConvToInt cconv))
, Var stbl_value
, Lit (LitLabel fe_nm mb_sz_args IsFunction)
, Lit (mkLitString typestring)
]
-- name of external entry point providing these services.
-- (probably in the RTS.)
adjustor = fsLit "createAdjustor"
-- Determine the number of bytes of arguments to the stub function,
-- so that we can attach the '@N' suffix to its label if it is a
-- stdcall on Windows.
mb_sz_args = case cconv of
StdCallConv -> Just args_size
_ -> Nothing
ccall_adj <- dsCCall adjustor adj_args PlayRisky (mkTyConApp io_tc [res_ty])
-- PlayRisky: the adjustor doesn't allocate in the Haskell heap or do a callback
let io_app = mkLams tvs $
Lam cback $
mkApps (Var bindIOId)
[ Type stable_ptr_ty
, Type res_ty
, mkApps (Var newStablePtrId) [ Type arg_ty, Var cback ]
, Lam stbl_value ccall_adj
]
fed = (id `setInlineActivation` NeverActive, Cast io_app co0)
-- Never inline the f.e.d. function, because the litlit
-- might not be in scope in other modules.
return ([fed], h_code, c_code)
toJsName :: Id -> String
toJsName i = renderWithContext defaultSDocContext (pprCode (ppr (idName i)))
dsJsCall :: Id -> Coercion -> ForeignCall -> Maybe Header
-> DsM ([(Id, Expr TyVar)], CHeader, CStub)
dsJsCall fn_id co (CCall (CCallSpec target cconv safety)) _mDeclHeader = do
let
ty = pFst $ coercionKind co
(tv_bndrs, rho) = tcSplitForAllTyVarBinders ty
(arg_tys, io_res_ty) = tcSplitFunTys rho
args <- newSysLocalsDs arg_tys -- no FFI levity-polymorphism
(val_args, arg_wrappers) <- mapAndUnzipM unboxJsArg (map Var args)
let
work_arg_ids = [v | Var v <- val_args] -- All guaranteed to be vars
(ccall_result_ty, res_wrapper) <- boxJsResult io_res_ty
ccall_uniq <- newUnique
work_uniq <- newUnique
simpl_opts <- initSimpleOpts <$> getDynFlags
let
-- Build the worker
fcall = CCall (CCallSpec target cconv safety)
worker_ty = mkForAllTys tv_bndrs (mkVisFunTysMany (map idType work_arg_ids) ccall_result_ty)
tvs = map binderVar tv_bndrs
the_ccall_app = mkFCall ccall_uniq fcall val_args ccall_result_ty
work_rhs = mkLams tvs (mkLams work_arg_ids the_ccall_app)
work_id = mkSysLocal (fsLit "$wccall") work_uniq ManyTy worker_ty
-- Build the wrapper
work_app = mkApps (mkVarApps (Var work_id) tvs) val_args
wrapper_body = foldr ($) (res_wrapper work_app) arg_wrappers
wrap_rhs = mkLams (tvs ++ args) wrapper_body
wrap_rhs' = Cast wrap_rhs co
fn_id_w_inl = fn_id
`setIdUnfolding`
mkInlineUnfoldingWithArity simpl_opts VanillaSrc
(length args) wrap_rhs'
return ([(work_id, work_rhs), (fn_id_w_inl, wrap_rhs')], mempty, mempty)
mkHObj :: Type -> SDoc
mkHObj t = text "h$rts_mk" <> showFFIType t
unpackHObj :: Type -> SDoc
unpackHObj t = text "h$rts_get" <> showFFIType t
showStgType :: Type -> SDoc
showStgType t = text "Hs" <> showFFIType t
showFFIType :: Type -> SDoc
showFFIType t = ftext (occNameFS (getOccName (typeTyCon t)))
typeTyCon :: Type -> TyCon
typeTyCon ty
-- UnaryRep rep_ty <- repType ty
| Just (tc, _) <- tcSplitTyConApp_maybe (unwrapType ty) -- rep_ty
= tc
| otherwise
= pprPanic "typeTyCon" (ppr ty)
{-
We unbox arguments for JS calls a bit different from native code:
- Bool is marshalled to true/false, not 0/1
- All int types are narrowed, since JS floats have a greater range than Int32
-}
unboxJsArg :: CoreExpr -- The supplied argument
-> DsM (CoreExpr, -- To pass as the actual argument
CoreExpr -> CoreExpr -- Wrapper to unbox the arg
)
unboxJsArg arg
-- Primtive types: nothing to unbox
| isPrimitiveType arg_ty
= return (arg, \body -> body)
-- Recursive newtypes
| Just (co, _rep_ty) <- topNormaliseNewType_maybe arg_ty
= unboxJsArg (mkCast arg co)
-- Booleans, do not convert to 0/1, only force them
| Just tc <- tyConAppTyCon_maybe arg_ty,
tc `hasKey` boolTyConKey
= return (arg,
\ body -> mkWildCase arg (unrestricted boolTy) (exprType body) [Alt DEFAULT [] body])
| Just tc <- tyConAppTyCon_maybe arg_ty,
tc `hasKey` anyTyConKey
= return (arg,
\ body -> mkWildCase arg (unrestricted arg_ty) (exprType body) [Alt DEFAULT [] body])
-- Data types with a single constructor, which has a single, primitive-typed arg
-- This deals with Int, Float etc; also Ptr, ForeignPtr
| is_product_type && data_con_arity == 1
= do case_bndr <- newSysLocalDs ManyTy arg_ty
prim_arg <- newSysLocalDs ManyTy (scaledThing data_con_arg_ty1)
return (Var prim_arg,
\ body -> Case arg case_bndr (exprType body) [Alt (DataAlt data_con) [prim_arg] body]
)
-- Byte-arrays, both mutable and otherwise; hack warning
-- We're looking for values of type ByteArray, MutableByteArray
-- data ByteArray ix = ByteArray ix ix ByteArray#
-- data MutableByteArray s ix = MutableByteArray ix ix (MutableByteArray# s)
| is_product_type &&
data_con_arity == 3 &&
isJust maybe_arg3_tycon &&
(arg3_tycon == byteArrayPrimTyCon ||
arg3_tycon == mutableByteArrayPrimTyCon)
= do case_bndr <- newSysLocalDs ManyTy arg_ty
vars@[_l_var, _r_var, arr_cts_var] <- newSysLocalsDs data_con_arg_tys
return (Var arr_cts_var,
\ body -> Case arg case_bndr (exprType body) [Alt (DataAlt data_con) vars body]
)
| otherwise
= do l <- getSrcSpanDs
pprPanic "unboxJsArg: " (ppr l <+> ppr arg_ty)
where
arg_ty = exprType arg
maybe_product_type = splitDataProductType_maybe arg_ty
is_product_type = isJust maybe_product_type
Just (_, _, data_con, data_con_arg_tys) = maybe_product_type
data_con_arity = dataConSourceArity data_con
(data_con_arg_ty1 : _) = data_con_arg_tys
(_ : _ : data_con_arg_ty3 : _) = data_con_arg_tys
maybe_arg3_tycon = tyConAppTyCon_maybe (scaledThing data_con_arg_ty3)
Just arg3_tycon = maybe_arg3_tycon
boxJsResult :: Type
-> DsM (Type, CoreExpr -> CoreExpr)
boxJsResult result_ty
| isRuntimeRepKindedTy result_ty = panic "boxJsResult: runtime rep ty" -- fixme
-- Takes the result of the user-level ccall:
-- either (IO t),
-- or maybe just t for an side-effect-free call
-- Returns a wrapper for the primitive ccall itself, along with the
-- type of the result of the primitive ccall. This result type
-- will be of the form
-- State# RealWorld -> (# State# RealWorld, t' #)
-- where t' is the unwrapped form of t. If t is simply (), then
-- the result type will be
-- State# RealWorld -> (# State# RealWorld #)
boxJsResult result_ty
| Just (io_tycon, io_res_ty) <- tcSplitIOType_maybe result_ty
-- isIOType_maybe handles the case where the type is a
-- simple wrapping of IO. E.g.
-- newtype Wrap a = W (IO a)
-- No coercion necessary because its a non-recursive newtype
-- (If we wanted to handle a *recursive* newtype too, we'd need
-- another case, and a coercion.)
-- The result is IO t, so wrap the result in an IO constructor
= do { res <- jsResultWrapper io_res_ty
; let return_result state ans
= mkCoreUnboxedTuple [state, ans]
; (ccall_res_ty, the_alt) <- mk_alt return_result res
; state_id <- newSysLocalDs ManyTy realWorldStatePrimTy
; let io_data_con = head (tyConDataCons io_tycon)
toIOCon = dataConWrapId io_data_con
wrap the_call =
mkApps (Var toIOCon)
[ Type io_res_ty,
Lam state_id $
mkWildCase (App the_call (Var state_id))
(unrestricted ccall_res_ty)
(coreAltType the_alt)
[the_alt]
]
; return (realWorldStatePrimTy `mkVisFunTyMany` ccall_res_ty, wrap) }
boxJsResult result_ty
= do -- It isn't IO, so do unsafePerformIO
-- It's not conveniently available, so we inline it
res <- jsResultWrapper result_ty
(ccall_res_ty, the_alt) <- mk_alt return_result res
let
wrap = \ the_call -> mkWildCase (App the_call (Var realWorldPrimId))
(unrestricted ccall_res_ty)
(coreAltType the_alt)
[the_alt]
return (realWorldStatePrimTy `mkVisFunTyMany` ccall_res_ty, wrap)
where
return_result _ ans = ans
mk_alt :: (Expr Var -> Expr Var -> Expr Var)
-> (Maybe Type, Expr Var -> Expr Var)
-> DsM (Type, CoreAlt)
mk_alt return_result (Nothing, wrap_result)
= do -- The ccall returns ()
state_id <- newSysLocalDs ManyTy realWorldStatePrimTy
let
the_rhs = return_result (Var state_id)
(wrap_result $ panic "jsBoxResult")
ccall_res_ty = mkTupleTy Unboxed [realWorldStatePrimTy]
the_alt = Alt (DataAlt (tupleDataCon Unboxed 1)) [state_id] the_rhs
return (ccall_res_ty, the_alt)
mk_alt return_result (Just prim_res_ty, wrap_result)
-- The ccall returns a non-() value
| isUnboxedTupleType prim_res_ty = do
let
Just ls = fmap dropRuntimeRepArgs (tyConAppArgs_maybe prim_res_ty)
arity = 1 + length ls
args_ids <- mapM (newSysLocalDs ManyTy) ls
state_id <- newSysLocalDs ManyTy realWorldStatePrimTy
let
result_tup = mkCoreUnboxedTuple (map Var args_ids)
the_rhs = return_result (Var state_id)
(wrap_result result_tup)
ccall_res_ty = mkTupleTy Unboxed (realWorldStatePrimTy : ls)
the_alt = Alt (DataAlt (tupleDataCon Unboxed arity))
(state_id : args_ids)
the_rhs
return (ccall_res_ty, the_alt)
| otherwise = do
result_id <- newSysLocalDs ManyTy prim_res_ty
state_id <- newSysLocalDs ManyTy realWorldStatePrimTy
let
the_rhs = return_result (Var state_id)
(wrap_result (Var result_id))
ccall_res_ty = mkTupleTy Unboxed [realWorldStatePrimTy, prim_res_ty]
the_alt = Alt (DataAlt (tupleDataCon Unboxed 2)) [state_id, result_id] the_rhs
return (ccall_res_ty, the_alt)
fun_type_arg_stdcall_info :: CCallConv -> Type -> Maybe Int
fun_type_arg_stdcall_info _other_conv _ = Nothing
jsResultWrapper
:: Type
-> DsM ( Maybe Type -- Type of the expected result, if any
, CoreExpr -> CoreExpr -- Wrapper for the result
)
-- resultWrapper deals with the result *value*
-- E.g. foreign import foo :: Int -> IO T
-- Then resultWrapper deals with marshalling the 'T' part
jsResultWrapper result_ty
| isRuntimeRepKindedTy result_ty = return (Nothing, id) -- fixme this seems like a hack
-- Base case 1a: unboxed tuples
| Just (tc, args) <- splitTyConApp_maybe result_ty
, isUnboxedTupleTyCon tc {- && False -} = do
let args' = dropRuntimeRepArgs args
(tys, wrappers) <- unzip <$> mapM jsResultWrapper args'
matched <- mapM (mapM (newSysLocalDs ManyTy)) tys
let tys' = catMaybes tys
-- arity = length args'
-- resCon = tupleDataCon Unboxed (length args)
err = panic "jsResultWrapper: used Id with result type Nothing"
resWrap :: CoreExpr
resWrap = mkCoreUnboxedTuple (zipWith (\w -> w . Var . fromMaybe err) wrappers matched)
return $
if null tys'
then (Nothing, \_ -> resWrap)
else let innerArity = length tys'
innerTy = mkTupleTy Unboxed tys'
innerCon = tupleDataCon Unboxed innerArity
inner :: CoreExpr -> CoreExpr
inner e = mkWildCase e (unrestricted innerTy) result_ty
[Alt (DataAlt innerCon)
(catMaybes matched)
resWrap
]
in (Just innerTy, inner)
-- Base case 1b: primitive types
| isPrimitiveType result_ty
= return (Just result_ty, \e -> e)
-- Base case 1c: boxed tuples
-- fixme: levity args?
| Just (tc, args) <- splitTyConApp_maybe result_ty
, isBoxedTupleTyCon tc = do
let args' = dropRuntimeRepArgs args
innerTy = mkTupleTy Unboxed args'
(inner_res, w) <- jsResultWrapper innerTy
matched <- mapM (newSysLocalDs ManyTy) args'
let inner e = mkWildCase (w e) (unrestricted innerTy) result_ty
[ Alt (DataAlt (tupleDataCon Unboxed (length args')))
matched
(mkCoreTup (map Var matched))
-- mkCoreConApps (tupleDataCon Boxed (length args)) (map Type args ++ map Var matched)
]
return (inner_res, inner)
-- Base case 2: the unit type ()
| Just (tc,_) <- maybe_tc_app, tc `hasKey` unitTyConKey
= return (Nothing, \_ -> Var unitDataConId)
-- Base case 3: the boolean type
| Just (tc,_) <- maybe_tc_app, tc `hasKey` boolTyConKey = do
-- result_id <- newSysLocalDs boolTy
ccall_uniq <- newUnique
let forceBool e = mkJsCall ccall_uniq (fsLit "((x) => { return !(!x); })") [e] boolTy
return
(Just intPrimTy, \e -> forceBool e)
-- Base case 4: the any type
| Just (tc,_) <- maybe_tc_app, tc `hasKey` anyTyConKey
= return (Just result_ty, \e -> e)
-- Newtypes
| Just (co, rep_ty) <- topNormaliseNewType_maybe result_ty
= do (maybe_ty, wrapper) <- jsResultWrapper rep_ty
return (maybe_ty, \e -> mkCastDs (wrapper e) (mkSymCo co))
-- The type might contain foralls (eg. for dummy type arguments,
-- referring to 'Ptr a' is legal).
| Just (tyvar, rest) <- splitForAllTyCoVar_maybe result_ty
= do (maybe_ty, wrapper) <- jsResultWrapper rest
return (maybe_ty, \e -> Lam tyvar (wrapper e))
-- Data types with a single constructor, which has a single arg
-- This includes types like Ptr and ForeignPtr
| Just (_tycon, tycon_arg_tys, data_con, data_con_arg_tys) <- splitDataProductType_maybe result_ty,
dataConSourceArity data_con == 1
= do let (unwrapped_res_ty : _) = data_con_arg_tys
(maybe_ty, wrapper) <- jsResultWrapper (scaledThing unwrapped_res_ty)
return
(maybe_ty, \e -> mkApps (Var (dataConWrapId data_con))
(map Type tycon_arg_tys ++ [wrapper e]))
| otherwise
= pprPanic "jsResultWrapper" (ppr result_ty)
where
maybe_tc_app = splitTyConApp_maybe result_ty
-- low-level primitive JavaScript call:
mkJsCall :: Unique -> FastString -> [CoreExpr] -> Type -> CoreExpr
mkJsCall u tgt args t = mkFCall u ccall args t
where
ccall = CCall $ CCallSpec
(StaticTarget NoSourceText tgt (Just primUnit) True)
JavaScriptCallConv
PlayRisky
|