{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}

module GHC.HsToCore.Foreign.Wasm
  ( dsWasmJSImport,
    dsWasmJSExport,
  )
where

import Data.List
  ( intercalate,
    stripPrefix,
  )
import Data.List qualified
import Data.Maybe
import GHC.Builtin.Names
import GHC.Builtin.Types
import GHC.Builtin.Types.Prim
import GHC.Core
import GHC.Core.Coercion
import GHC.Core.DataCon
import GHC.Core.Make
import GHC.Core.Multiplicity
import GHC.Core.TyCon
import GHC.Core.Type
import GHC.Core.Utils
import GHC.Data.FastString
import GHC.Hs
import GHC.HsToCore.Foreign.Call
import GHC.HsToCore.Foreign.Utils
import GHC.HsToCore.Monad
import GHC.HsToCore.Types
import GHC.Iface.Env
import GHC.Prelude
import GHC.Tc.Utils.Env
import GHC.Tc.Utils.Monad
import GHC.Tc.Utils.TcType
import GHC.Types.ForeignCall
import GHC.Types.ForeignStubs
import GHC.Types.Id
import GHC.Types.Name
import GHC.Types.SourceText
import GHC.Types.SrcLoc
import GHC.Types.Var
import GHC.Unit
import GHC.Utils.Outputable
import GHC.Utils.Panic
import Language.Haskell.Syntax.Basic

data Synchronicity = Sync | Async
  deriving (Synchronicity -> Synchronicity -> Bool
(Synchronicity -> Synchronicity -> Bool)
-> (Synchronicity -> Synchronicity -> Bool) -> Eq Synchronicity
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: Synchronicity -> Synchronicity -> Bool
== :: Synchronicity -> Synchronicity -> Bool
$c/= :: Synchronicity -> Synchronicity -> Bool
/= :: Synchronicity -> Synchronicity -> Bool
Eq)

dsWasmJSImport ::
  Id ->
  Coercion ->
  CImportSpec ->
  Safety ->
  DsM ([Binding], CHeader, CStub, [Id])
dsWasmJSImport :: Id
-> Coercion
-> CImportSpec
-> Safety
-> DsM ([Binding], CHeader, CStub, [Id])
dsWasmJSImport Id
id Coercion
co (CFunction (StaticTarget SourceText
_ FastString
js_src Maybe Unit
mUnitId Bool
_)) Safety
safety
  | FastString
js_src FastString -> FastString -> Bool
forall a. Eq a => a -> a -> Bool
== FastString
"wrapper" = Synchronicity
-> Id
-> Coercion
-> Maybe Unit
-> DsM ([Binding], CHeader, CStub, [Id])
dsWasmJSDynamicExport Synchronicity
Async Id
id Coercion
co Maybe Unit
mUnitId
  | FastString
js_src FastString -> FastString -> Bool
forall a. Eq a => a -> a -> Bool
== FastString
"wrapper sync" = Synchronicity
-> Id
-> Coercion
-> Maybe Unit
-> DsM ([Binding], CHeader, CStub, [Id])
dsWasmJSDynamicExport Synchronicity
Sync Id
id Coercion
co Maybe Unit
mUnitId
  | Bool
otherwise = do
      (bs, h, c) <- Id
-> Coercion
-> String
-> Maybe Unit
-> Synchronicity
-> DsM ([Binding], CHeader, CStub)
dsWasmJSStaticImport Id
id Coercion
co (FastString -> String
unpackFS FastString
js_src) Maybe Unit
mUnitId Synchronicity
sync
      pure (bs, h, c, [])
  where
    sync :: Synchronicity
sync = case Safety
safety of
      Safety
PlayRisky -> Synchronicity
Sync
      Safety
_ -> Synchronicity
Async
dsWasmJSImport Id
_ Coercion
_ CImportSpec
_ Safety
_ = String -> DsM ([Binding], CHeader, CStub, [Id])
forall a. HasCallStack => String -> a
panic String
"dsWasmJSImport: unreachable"

{-

Note [Desugaring JSFFI dynamic export]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A JSFFI dynamic export wraps a Haskell function as a JavaScript
callback:

foreign import javascript "wrapper"
  mk_wrapper :: HsFuncType -> IO JSVal

We desugar it to three bindings under the hood:

1. The worker function

mk_wrapper_worker :: StablePtr HsFuncType -> HsFuncType
mk_wrapper_worker sp = unsafeDupablePerformIO (deRefStablePtr sp)

The worker function is marked as a JSFFI static export. It turns a
dynamic export to a static one by prepending a StablePtr to the
argument list.

We don't actually generate a Core binding for the worker function
though; the JSFFI static export C stub generation logic would just
generate a function that doesn't need to refer to the worker Id's
closure. This is not just for convenience, it's actually required for
correctness, see #25473.

2. The adjustor function

foreign import javascript unsafe "(...args) => __exports.mk_wrapper_worker($1, ...args)"
  mk_wrapper_adjustor :: StablePtr HsFuncType -> IO JSVal

Now that mk_wrapper_worker is exported in __exports, we need to make a
JavaScript callback that invokes mk_wrapper_worker with the right
StablePtr as well as the rest of the arguments.

3. The wrapper function

mk_wrapper :: HsFuncType -> IO JSVal
mk_wrapper = mkJSCallback mk_wrapper_adjustor

This is the user-facing mk_wrapper binding. It allocates a stable
pointer for the Haskell function closure, then calls the adjustor
function to fetch the JSVal that represents the JavaScript callback.
The JSVal as returned by the adjustor is not returned directly; it has
a StablePtr# field which is NULL by default, but for JSFFI dynamic
exports, it's set to the Haskell function's stable pointer. This way,
when we call freeJSVal, the Haskell function can be freed as well.

By default, JSFFI exports are async JavaScript functions. One can use
"wrapper sync" instead of "wrapper" to indicate the Haskell function
is meant to be exported as a sync JavaScript function. All the
comments above still hold, with only only difference:
mk_wrapper_worker is exported as a sync function. See
Note [Desugaring JSFFI static export] for further details.

-}

dsWasmJSDynamicExport ::
  Synchronicity ->
  Id ->
  Coercion ->
  Maybe Unit ->
  DsM ([Binding], CHeader, CStub, [Id])
dsWasmJSDynamicExport :: Synchronicity
-> Id
-> Coercion
-> Maybe Unit
-> DsM ([Binding], CHeader, CStub, [Id])
dsWasmJSDynamicExport Synchronicity
sync Id
fn_id Coercion
co Maybe Unit
mUnitId = do
  sp_tycon <- Name -> DsM TyCon
dsLookupTyCon Name
stablePtrTyConName
  let ty = HasDebugCallStack => Coercion -> Type
Coercion -> Type
coercionLKind Coercion
co
      (tv_bndrs, fun_ty) = tcSplitForAllTyVarBinders ty
      ([Scaled ManyTy arg_ty], io_jsval_ty) = tcSplitFunTys fun_ty
      sp_ty = TyCon -> [Type] -> Type
mkTyConApp TyCon
sp_tycon [Type
arg_ty]
  sp_id <- newSysLocalMDs sp_ty
  work_export_name <- unpackFS <$> uniqueCFunName
  deRefStablePtr_id <-
    lookupGhcInternalVarId
      "GHC.Internal.Stable"
      "deRefStablePtr"
  unsafeDupablePerformIO_id <-
    lookupGhcInternalVarId
      "GHC.Internal.IO.Unsafe"
      "unsafeDupablePerformIO"
  let work_rhs =
        [Id] -> CoreExpr -> CoreExpr
mkCoreLams ([Id
tv | Bndr Id
tv ForAllTyFlag
_ <- [TyVarBinder]
tv_bndrs] [Id] -> [Id] -> [Id]
forall a. [a] -> [a] -> [a]
++ [Id
sp_id])
          (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$ CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
            (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
unsafeDupablePerformIO_id)
            [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
arg_ty, CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
deRefStablePtr_id) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
arg_ty, Id -> CoreExpr
forall b. Id -> Expr b
Var Id
sp_id]]
      work_ty = HasDebugCallStack => CoreExpr -> Type
CoreExpr -> Type
exprType CoreExpr
work_rhs
  (work_h, work_c, _, work_ids, work_bs) <-
    dsWasmJSExport'
      sync
      Nothing
      (mkRepReflCo work_ty)
      work_export_name
  adjustor_uniq <- newUnique
  let adjustor_id =
        Name -> Type -> Id
mkExportedVanillaId
          ( Unique -> Module -> OccName -> SrcSpan -> Name
mkExternalName
              Unique
adjustor_uniq
              (HasDebugCallStack => Name -> Module
Name -> Module
nameModule (Name -> Module) -> Name -> Module
forall a b. (a -> b) -> a -> b
$ Id -> Name
forall a. NamedThing a => a -> Name
getName Id
fn_id)
              ( String -> OccName
mkVarOcc
                  (String -> OccName) -> String -> OccName
forall a b. (a -> b) -> a -> b
$ String
"jsffi_"
                  String -> String -> String
forall a. [a] -> [a] -> [a]
++ OccName -> String
occNameString (Id -> OccName
forall a. NamedThing a => a -> OccName
getOccName Id
fn_id)
                  String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
"_adjustor"
              )
              SrcSpan
generatedSrcSpan
          )
          Type
adjustor_ty
      adjustor_ty = [TyVarBinder] -> Type -> Type
mkForAllTys [TyVarBinder]
tv_bndrs (Type -> Type) -> Type -> Type
forall a b. (a -> b) -> a -> b
$ [Type] -> Type -> Type
mkVisFunTysMany [Type
sp_ty] Type
io_jsval_ty
      adjustor_js_src =
        String
"(...args) => __exports." String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
work_export_name String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
"($1, ...args)"
  (adjustor_bs, adjustor_h, adjustor_c) <-
    dsWasmJSStaticImport
      adjustor_id
      (mkRepReflCo adjustor_ty)
      adjustor_js_src
      mUnitId
      Sync
  mkJSCallback_id <-
    lookupGhcInternalVarId
      "GHC.Internal.Wasm.Prim.Exports"
      "mkJSCallback"
  let wrap_rhs =
        [Id] -> CoreExpr -> CoreExpr
mkCoreLams [Id
tv | Bndr Id
tv ForAllTyFlag
_ <- [TyVarBinder]
tv_bndrs]
          (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$ CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
            (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
mkJSCallback_id)
            [ Type -> CoreExpr
forall b. Type -> Expr b
Type Type
arg_ty,
              CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
                (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
adjustor_id)
                [Type -> CoreExpr
forall b. Type -> Expr b
Type (Type -> CoreExpr) -> Type -> CoreExpr
forall a b. (a -> b) -> a -> b
$ Id -> Type
mkTyVarTy Id
tv | Bndr Id
tv ForAllTyFlag
_ <- [TyVarBinder]
tv_bndrs]
            ]
  pure
    ( [(fn_id, Cast wrap_rhs co)] ++ work_bs ++ adjustor_bs,
      work_h `mappend` adjustor_h,
      work_c `mappend` adjustor_c,
      work_ids
    )

{-

Note [Desugaring JSFFI import]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The simplest case is JSFFI sync import, those marked as unsafe. It is
implemented on top of C FFI safe import.

Unlike C FFI which generates a worker/wrapper pair that unboxes the
arguments and boxes the result in Haskell, we only desugar to a single
Haskell binding that case-binds the arguments to ensure they're
evaluated, then passes the boxed arguments directly to C and receive
the boxed result from C as well.

This is slightly less efficient than how C FFI does it, and unboxed
FFI types aren't supported, but it's the simplest way to implement it,
especially since leaving all the boxing/unboxing business to C unifies
the implementation of JSFFI imports and exports
(rts_mkJSVal/rts_getJSVal).

Now, each sync import calls a generated C function with a unique
symbol. The C function uses rts_get* to unbox the arguments, call into
JavaScript, then boxes the result with rts_mk* and returns it to
Haskell. But wait, how on earth is C able to call into JavaScript
here!? The secret is using a wasm import:

__attribute__((import_module("ghc_wasm_jsffi"), import_name("my_js_func")))
HsJSVal worker_func(HsInt a1, HsJSVal a2);

Wasm imports live in the same namespace as other wasm functions, so
our C wrapper function can call into this imported worker function,
which will literally be the user written JavaScript function with
binders $1, $2, etc.

So far so good, but how does the source code snippet go from Haskell
source files to the JavaScript module which provides the
ghc_wasm_jsffi imports to be used by the wasm module at runtime? The
secret is embedding the source code snippets in a wasm custom section
named ghc_wasm_jsffi:

.section .custom_section.ghc_wasm_jsffi,"",@
.asciz my_js_func
.asciz ($1, $2)
.asciz js_code_containing($1, $2)

At link time, for all object files touched by wasm-ld, all
ghc_wasm_jsffi sections are concatenated into a single ghc_wasm_jsffi
section in the output wasm module. And then, a simple "post-linker"
program can parse the payload of that section and emit a JavaScript
module. Note that above is assembly source file, but we're only
generating a C stub, so we need to smuggle the assembly code into C
via __asm__.

The C FFI import that calls the generated C function is always marked
as safe. There is some extra overhead, but this allows re-entrance by
Haskell -> JavaScript -> Haskell function calls with each call being a
synchronous one. It's possible to steal the "interruptible" keyword to
indicate async imports, "safe" for sync imports and "unsafe" for sync
imports sans the safe C FFI overhead, but it's simply not worth the
extra complexity.

JSFFI async import is implemented on top of JSFFI sync import. We
still desugar it to a single Haskell binding that calls C, with some
subtle differences:

- The C result type is always a boxed JSVal that represents the
  JavaScript Promise, instead of the actual Haskell result type.
- In the custom section payload, we emit "async ($1, $2)" instead of
  "($1, $2)". As you can see, it is the arrow function binder, and the
  post-linker will respect the async binder and allow await in the
  function body.

Now we have the Promise JSVal, we apply stg_blockPromise to it to get
a thunk with the desired return type. When the thunk is forced, it
will block the forcing thread and wait for the Promise to resolve or
reject. See Note [stg_blockPromise] for detailed explanation of how it
works.

-}

dsWasmJSStaticImport ::
  Id ->
  Coercion ->
  String ->
  Maybe Unit ->
  Synchronicity ->
  DsM ([Binding], CHeader, CStub)
dsWasmJSStaticImport :: Id
-> Coercion
-> String
-> Maybe Unit
-> Synchronicity
-> DsM ([Binding], CHeader, CStub)
dsWasmJSStaticImport Id
fn_id Coercion
co String
js_src' Maybe Unit
mUnitId Synchronicity
sync = do
  cfun_name <- IOEnv (Env DsGblEnv DsLclEnv) FastString
uniqueCFunName
  let ty = HasDebugCallStack => Coercion -> Type
Coercion -> Type
coercionLKind Coercion
co
      (tvs, fun_ty) = tcSplitForAllInvisTyVars ty
      (arg_tys, orig_res_ty) = tcSplitFunTys fun_ty
      (res_ty, is_io) = case tcSplitIOType_maybe orig_res_ty of
        Just (TyCon
_, Type
res_ty) -> (Type
res_ty, Bool
True)
        Maybe (TyCon, Type)
Nothing -> (Type
orig_res_ty, Bool
False)
      js_src
        -- Just desugar it to a JSFFI import with source text "$1($2,
        -- ...)", with the same type signature and safety annotation.
        | String
js_src' String -> String -> Bool
forall a. Eq a => a -> a -> Bool
== String
"dynamic" =
            String
"$1("
              String -> String -> String
forall a. [a] -> [a] -> [a]
++ String -> [String] -> String
forall a. [a] -> [[a]] -> [a]
intercalate String
"," [String
"$" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Int -> String
forall a. Show a => a -> String
show Int
i | Int
i <- [Int
2 .. [Scaled Type] -> Int
forall a. [a] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Scaled Type]
arg_tys]]
              String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
")"
        | Bool
otherwise =
            String
js_src'
  case sync of
    Synchronicity
Sync -> do
      rhs <- Maybe Unit
-> FastString
-> [Id]
-> [Scaled Type]
-> Type
-> (CoreExpr -> CoreExpr)
-> DsM CoreExpr
importBindingRHS Maybe Unit
mUnitId FastString
cfun_name [Id]
tvs [Scaled Type]
arg_tys Type
orig_res_ty CoreExpr -> CoreExpr
forall a. a -> a
id
      pure
        ( [(fn_id, Cast rhs co)],
          CHeader commonCDecls,
          importCStub Sync cfun_name (map scaledThing arg_tys) res_ty js_src
        )
    Synchronicity
Async -> do
      err_msg <- String -> DsM CoreExpr
forall (m :: * -> *). MonadThings m => String -> m CoreExpr
mkStringExpr (String -> DsM CoreExpr) -> String -> DsM CoreExpr
forall a b. (a -> b) -> a -> b
$ String
js_src
      io_tycon <- dsLookupTyCon ioTyConName
      jsval_ty <-
        mkTyConTy
          <$> lookupGhcInternalTyCon "GHC.Internal.Wasm.Prim.Types" "JSVal"
      bindIO_id <- dsLookupGlobalId bindIOName
      returnIO_id <- dsLookupGlobalId returnIOName
      promise_id <- newSysLocalMDs jsval_ty
      blockPromise_id <-
        lookupGhcInternalVarId
          "GHC.Internal.Wasm.Prim.Imports"
          "stg_blockPromise"
      msgPromise_id <-
        lookupGhcInternalVarId "GHC.Internal.Wasm.Prim.Imports"
          $ "stg_messagePromise"
          ++ ffiType res_ty
      unsafeDupablePerformIO_id <-
        lookupGhcInternalVarId
          "GHC.Internal.IO.Unsafe"
          "unsafeDupablePerformIO"
      rhs <-
        importBindingRHS
          mUnitId
          cfun_name
          tvs
          arg_tys
          (mkTyConApp io_tycon [jsval_ty])
          $ ( if is_io
                then id
                else \CoreExpr
m_res ->
                  CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
unsafeDupablePerformIO_id) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
res_ty, CoreExpr
m_res]
            )
          -- (m_promise :: IO JSVal) >>= (\promise -> return (stg_blockPromise promise msgPromise))
          -- stg_blockPromise returns the thunk
          . ( \CoreExpr
m_promise ->
                CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
                  (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
bindIO_id)
                  [ Type -> CoreExpr
forall b. Type -> Expr b
Type Type
jsval_ty,
                    Type -> CoreExpr
forall b. Type -> Expr b
Type Type
res_ty,
                    CoreExpr
m_promise,
                    Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
promise_id
                      (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$ CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
                        (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
returnIO_id)
                        [ Type -> CoreExpr
forall b. Type -> Expr b
Type Type
res_ty,
                          CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
                            (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
blockPromise_id)
                            [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
res_ty, CoreExpr
err_msg, Id -> CoreExpr
forall b. Id -> Expr b
Var Id
promise_id, Id -> CoreExpr
forall b. Id -> Expr b
Var Id
msgPromise_id]
                        ]
                  ]
            )
      pure
        ( [(fn_id, Cast rhs co)],
          CHeader commonCDecls,
          importCStub Async cfun_name (map scaledThing arg_tys) jsval_ty js_src
        )

uniqueCFunName :: DsM FastString
uniqueCFunName :: IOEnv (Env DsGblEnv DsLclEnv) FastString
uniqueCFunName = do
  cfun_num <- DsGblEnv -> IORef (ModuleEnv Int)
ds_next_wrapper_num (DsGblEnv -> IORef (ModuleEnv Int))
-> IOEnv (Env DsGblEnv DsLclEnv) DsGblEnv
-> IOEnv (Env DsGblEnv DsLclEnv) (IORef (ModuleEnv Int))
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> IOEnv (Env DsGblEnv DsLclEnv) DsGblEnv
forall gbl lcl. TcRnIf gbl lcl gbl
getGblEnv
  mkWrapperName cfun_num "ghc_wasm_jsffi" ""

importBindingRHS ::
  Maybe Unit ->
  FastString ->
  [TyVar] ->
  [Scaled Type] ->
  Type ->
  (CoreExpr -> CoreExpr) ->
  DsM CoreExpr
importBindingRHS :: Maybe Unit
-> FastString
-> [Id]
-> [Scaled Type]
-> Type
-> (CoreExpr -> CoreExpr)
-> DsM CoreExpr
importBindingRHS Maybe Unit
mUnitId FastString
cfun_name [Id]
tvs [Scaled Type]
arg_tys Type
orig_res_ty CoreExpr -> CoreExpr
res_trans = do
  ccall_uniq <- TcRnIf DsGblEnv DsLclEnv Unique
forall gbl lcl. TcRnIf gbl lcl Unique
newUnique
  args_unevaled <- newSysLocalsDs arg_tys
  args_evaled <- newSysLocalsDs arg_tys
  -- ccall_action_ty: type of the_call, State# RealWorld -> (# State# RealWorld, a #)
  -- res_wrapper: turn the_call to (IO a) or a
  (ccall_action_ty, res_wrapper) <- case tcSplitIOType_maybe orig_res_ty of
    Just (TyCon
io_tycon, Type
res_ty) -> do
      s0_id <- Type -> DsM Id
newSysLocalMDs Type
realWorldStatePrimTy
      s1_id <- newSysLocalMDs realWorldStatePrimTy
      let io_data_con = TyCon -> DataCon
tyConSingleDataCon TyCon
io_tycon
          toIOCon = DataCon -> Id
dataConWorkId DataCon
io_data_con
          (ccall_res_ty, wrap)
            | res_ty `eqType` unitTy =
                ( mkTupleTy Unboxed [realWorldStatePrimTy],
                  \CoreExpr
the_call ->
                    CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
                      (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
toIOCon)
                      [ Type -> CoreExpr
forall b. Type -> Expr b
Type Type
res_ty,
                        Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
s0_id
                          (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$ CoreExpr -> Scaled Type -> Type -> [CoreAlt] -> CoreExpr
mkWildCase
                            (CoreExpr -> CoreExpr -> CoreExpr
forall b. Expr b -> Expr b -> Expr b
App CoreExpr
the_call (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
s0_id))
                            (Type -> Scaled Type
forall a. a -> Scaled a
unrestricted Type
ccall_res_ty)
                            (Boxity -> [Type] -> Type
mkTupleTy Boxity
Unboxed [Type
realWorldStatePrimTy, Type
unitTy])
                            [ AltCon -> [Id] -> CoreExpr -> CoreAlt
forall b. AltCon -> [b] -> Expr b -> Alt b
Alt
                                (DataCon -> AltCon
DataAlt (Boxity -> Int -> DataCon
tupleDataCon Boxity
Unboxed Int
1))
                                [Id
s1_id]
                                ([CoreExpr] -> CoreExpr
mkCoreUnboxedTuple [Id -> CoreExpr
forall b. Id -> Expr b
Var Id
s1_id, CoreExpr
unitExpr])
                            ]
                      ]
                )
            | otherwise =
                ( mkTupleTy Unboxed [realWorldStatePrimTy, res_ty],
                  \CoreExpr
the_call -> CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
toIOCon) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
res_ty, CoreExpr
the_call]
                )
      pure (realWorldStatePrimTy `mkVisFunTyMany` ccall_res_ty, wrap)
    Maybe (TyCon, Type)
Nothing -> do
      unsafeDupablePerformIO_id <-
        FastString -> String -> DsM Id
lookupGhcInternalVarId
          FastString
"GHC.Internal.IO.Unsafe"
          String
"unsafeDupablePerformIO"
      io_data_con <- dsLookupDataCon ioDataConName
      let ccall_res_ty = Boxity -> [Type] -> Type
mkTupleTy Boxity
Unboxed [Type
realWorldStatePrimTy, Type
orig_res_ty]
          toIOCon = DataCon -> Id
dataConWorkId DataCon
io_data_con
          wrap CoreExpr
the_call =
            CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps
              (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
unsafeDupablePerformIO_id)
              [ Type -> CoreExpr
forall b. Type -> Expr b
Type Type
orig_res_ty,
                CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
toIOCon) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
orig_res_ty, CoreExpr
the_call]
              ]
      pure (realWorldStatePrimTy `mkVisFunTyMany` ccall_res_ty, wrap)
  let cfun_fcall =
        CCallSpec -> ForeignCall
CCall
          ( CCallTarget -> CCallConv -> Safety -> CCallSpec
CCallSpec
              (SourceText -> FastString -> Maybe Unit -> Bool -> CCallTarget
StaticTarget SourceText
NoSourceText FastString
cfun_name Maybe Unit
mUnitId Bool
True)
              CCallConv
CCallConv
              -- Same even for foreign import javascript unsafe, for
              -- the sake of re-entrancy.
              Safety
PlaySafe
          )
      call_app =
        Unique -> ForeignCall -> [CoreExpr] -> Type -> CoreExpr
mkFCall Unique
ccall_uniq ForeignCall
cfun_fcall ((Id -> CoreExpr) -> [Id] -> [CoreExpr]
forall a b. (a -> b) -> [a] -> [b]
map Id -> CoreExpr
forall b. Id -> Expr b
Var [Id]
args_evaled) Type
ccall_action_ty
      rhs =
        [Id] -> CoreExpr -> CoreExpr
mkCoreLams ([Id]
tvs [Id] -> [Id] -> [Id]
forall a. [a] -> [a] -> [a]
++ [Id]
args_unevaled)
          (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$ ((Id, Id) -> CoreExpr -> CoreExpr)
-> CoreExpr -> [(Id, Id)] -> CoreExpr
forall a b. (a -> b -> b) -> b -> [a] -> b
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr
            (\(Id
arg_u, Id
arg_e) CoreExpr
acc -> CoreExpr -> Id -> CoreExpr -> CoreExpr
mkDefaultCase (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
arg_u) Id
arg_e CoreExpr
acc)
            -- res_trans transforms the result. When desugaring
            -- JSFFI sync imports, the result is just (IO a) or a,
            -- and res_trans is id; for async cases, the result is
            -- always (IO JSVal), and res_trans will wrap it in a
            -- thunk that has the original return type. This way, we
            -- can reuse most of the RHS generation logic for both
            -- sync/async imports.
            (CoreExpr -> CoreExpr
res_trans (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$ CoreExpr -> CoreExpr
res_wrapper CoreExpr
call_app)
            ([Id] -> [Id] -> [(Id, Id)]
forall a b. [a] -> [b] -> [(a, b)]
zip [Id]
args_unevaled [Id]
args_evaled)
  pure rhs

importCStub :: Synchronicity -> FastString -> [Type] -> Type -> String -> CStub
importCStub :: Synchronicity -> FastString -> [Type] -> Type -> String -> CStub
importCStub Synchronicity
sync FastString
cfun_name [Type]
arg_tys Type
res_ty String
js_src = SDoc -> [CLabel] -> [CLabel] -> CStub
CStub SDoc
c_doc [] []
  where
    import_name :: String
import_name = Maybe String -> String
forall a. HasCallStack => Maybe a -> a
fromJust (Maybe String -> String) -> Maybe String -> String
forall a b. (a -> b) -> a -> b
$ String -> String -> Maybe String
forall a. Eq a => [a] -> [a] -> Maybe [a]
stripPrefix String
"ghczuwasmzujsffi" (FastString -> String
unpackFS FastString
cfun_name)
    import_asm :: SDoc
import_asm =
      String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"__asm__"
        SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens
          ( [SDoc] -> SDoc
forall doc. IsDoc doc => [doc] -> doc
vcat
              [ String -> SDoc
forall doc. IsLine doc => String -> doc
text (String -> String
forall a. Show a => a -> String
show String
l)
              | String
l <-
                  [ String
".section .custom_section.ghc_wasm_jsffi,\"\",@\n",
                    String
".asciz \"" String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
import_name String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
"\"\n",
                    String
".asciz \""
                      String -> String -> String
forall a. [a] -> [a] -> [a]
++ ( case Synchronicity
sync of
                             Synchronicity
Sync -> String
"("
                             Synchronicity
Async -> String
"async ("
                         )
                      String -> String -> String
forall a. [a] -> [a] -> [a]
++ String -> [String] -> String
forall a. [a] -> [[a]] -> [a]
intercalate String
"," [String
"$" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Int -> String
forall a. Show a => a -> String
show Int
i | Int
i <- [Int
1 .. [Type] -> Int
forall a. [a] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Type]
arg_tys]]
                      String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
")\"\n",
                    String
".asciz " String -> String -> String
forall a. [a] -> [a] -> [a]
++ String -> String
forall a. Show a => a -> String
show String
js_src String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
"\n"
                  ]
              ]
          )
        SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi
    import_attr :: SDoc
import_attr =
      String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"__attribute__"
        SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens
          ( SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens
              ( [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
hsep
                  ( SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate
                      SDoc
forall doc. IsLine doc => doc
comma
                      [ String -> SDoc
forall doc. IsLine doc => String -> doc
text String
k SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens (SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
doubleQuotes (String -> SDoc
forall doc. IsLine doc => String -> doc
text String
v))
                      | (String
k, String
v) <-
                          [(String
"import_module", String
"ghc_wasm_jsffi"), (String
"import_name", String
import_name)]
                      ]
                  )
              )
          )
    import_proto :: SDoc
import_proto =
      SDoc
import_res_ty SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
import_name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens SDoc
import_args SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi
    import_res_ty :: SDoc
import_res_ty
      | Type
res_ty HasCallStack => Type -> Type -> Bool
Type -> Type -> Bool
`eqType` Type
unitTy = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"void"
      | Bool
otherwise = String -> SDoc
forall doc. IsLine doc => String -> doc
text (String
"Hs" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
ffiType Type
res_ty)
    import_arg_list :: [SDoc]
import_arg_list =
      [ String -> SDoc
forall doc. IsLine doc => String -> doc
text (String
"Hs" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
ffiType Type
arg_ty) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'a' SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> Int -> SDoc
forall doc. IsLine doc => Int -> doc
int Int
i
      | (Int
i, Type
arg_ty) <- [Int] -> [Type] -> [(Int, Type)]
forall a b. [a] -> [b] -> [(a, b)]
zip [Int
1 ..] [Type]
arg_tys
      ]
    import_args :: SDoc
import_args = case [SDoc]
import_arg_list of
      [] -> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"void"
      [SDoc]
_ -> [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
hsep ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall a b. (a -> b) -> a -> b
$ SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma [SDoc]
import_arg_list
    cfun_proto :: SDoc
cfun_proto = SDoc
cfun_res_ty SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> FastString -> SDoc
forall a. Outputable a => a -> SDoc
ppr FastString
cfun_name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens SDoc
cfun_args
    cfun_ret :: SDoc
cfun_ret
      | Type
res_ty HasCallStack => Type -> Type -> Bool
Type -> Type -> Bool
`eqType` Type
unitTy = SDoc
cfun_call_import SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi
      | Bool
otherwise = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"return" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
cfun_call_import SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi
    cfun_make_arg :: Type -> doc -> doc
cfun_make_arg Type
arg_ty doc
arg_val =
      String -> doc
forall doc. IsLine doc => String -> doc
text (String
"rts_get" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
ffiType Type
arg_ty) doc -> doc -> doc
forall doc. IsLine doc => doc -> doc -> doc
<> doc -> doc
forall doc. IsLine doc => doc -> doc
parens doc
arg_val
    cfun_make_ret :: SDoc -> SDoc
cfun_make_ret SDoc
ret_val
      | Type
res_ty HasCallStack => Type -> Type -> Bool
Type -> Type -> Bool
`eqType` Type
unitTy = SDoc
ret_val
      | Bool
otherwise =
          String -> SDoc
forall doc. IsLine doc => String -> doc
text (String
"rts_mk" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
ffiType Type
res_ty)
            -- We can cheat a little bit here since there's only
            -- MainCapability in the single-threaded RTS anyway, so no
            -- need to call rts_unsafeGetMyCapability().
            SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens ([SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
hsep (SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma [String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"&MainCapability", SDoc
ret_val]))
    cfun_call_import :: SDoc
cfun_call_import =
      SDoc -> SDoc
cfun_make_ret
        (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$ String -> SDoc
forall doc. IsLine doc => String -> doc
text String
import_name
        SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens
          ( [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
hsep
              ( SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate
                  SDoc
forall doc. IsLine doc => doc
comma
                  [ Type -> SDoc -> SDoc
forall {doc}. IsLine doc => Type -> doc -> doc
cfun_make_arg Type
arg_ty (Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'a' SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> Int -> SDoc
forall doc. IsLine doc => Int -> doc
int Int
n)
                  | (Type
arg_ty, Int
n) <- [Type] -> [Int] -> [(Type, Int)]
forall a b. [a] -> [b] -> [(a, b)]
zip [Type]
arg_tys [Int
1 ..]
                  ]
              )
          )
    cfun_res_ty :: SDoc
cfun_res_ty
      | Type
res_ty HasCallStack => Type -> Type -> Bool
Type -> Type -> Bool
`eqType` Type
unitTy = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"void"
      | Bool
otherwise = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"HaskellObj"
    cfun_arg_list :: [SDoc]
cfun_arg_list =
      [String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"HaskellObj" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'a' SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> Int -> SDoc
forall doc. IsLine doc => Int -> doc
int Int
n | Int
n <- [Int
1 .. [Type] -> Int
forall a. [a] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Type]
arg_tys]]
    cfun_args :: SDoc
cfun_args = case [SDoc]
cfun_arg_list of
      [] -> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"void"
      [SDoc]
_ -> [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
hsep ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall a b. (a -> b) -> a -> b
$ SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma [SDoc]
cfun_arg_list
    c_doc :: SDoc
c_doc =
      SDoc
commonCDecls
        SDoc -> SDoc -> SDoc
$+$ SDoc
import_asm
        SDoc -> SDoc -> SDoc
$+$ SDoc
import_attr
        SDoc -> SDoc -> SDoc
$+$ SDoc
import_proto
        SDoc -> SDoc -> SDoc
$+$ SDoc
cfun_proto
        SDoc -> SDoc -> SDoc
$+$ SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
braces SDoc
cfun_ret

{-

Note [Desugaring JSFFI static export]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A JSFFI static export wraps a top-level Haskell binding as a wasm
module export that can be called in JavaScript as an async/sync
function:

foreign export javascript "plus"
  (+) :: Int -> Int -> Int

Just like generating C stub for a JSFFI import, we need to generate C
stub for a JSFFI export as well:

__attribute__((export_name("plus")))
HsJSVal plus(HsInt a1, HsInt a2) { ... }

The generated C stub function would be exported as __exports.plus and
can be called in JavaScript. By default, it's exported as an async
function, so the C stub would always return an HsJSVal which
represents the result Promise; in case of a sync export (using "plus
sync" instead of "plus"), it returns the original result type.

The C stub function body applies the function closure to arguments,
wrap it with a runIO/runNonIO top handler function, then schedules
Haskell computation to happen, then fetches the result. In case of an
async export, the top handler creates a JavaScript Promise that stands
for Haskell evaluation result, and the Promise will eventually be
resolved with the result or rejected with an exception. That Promise
is what we return in the C stub function. See
Note [Async JSFFI scheduler] for detailed explanation.

At link time, you need to pass -optl-Wl,--export=plus,--export=... to
specify your entrypoint function symbols as roots of wasm-ld link-time
garbage collection. As for the auto-generated exports when desugaring
the JSFFI dynamic exports, they will be transitively included as well
due to the export_name attribute.

-}

dsWasmJSExport ::
  Id ->
  Coercion ->
  CLabelString ->
  DsM (CHeader, CStub, String, [Id], [Binding])
dsWasmJSExport :: Id
-> Coercion
-> FastString
-> DsM (CHeader, CStub, String, [Id], [Binding])
dsWasmJSExport Id
fn_id Coercion
co FastString
str = Synchronicity
-> Maybe Id
-> Coercion
-> String
-> DsM (CHeader, CStub, String, [Id], [Binding])
dsWasmJSExport' Synchronicity
sync (Id -> Maybe Id
forall a. a -> Maybe a
Just Id
fn_id) Coercion
co String
ext_name
  where
    (Synchronicity
sync, String
ext_name) = case String -> [String]
words (String -> [String]) -> String -> [String]
forall a b. (a -> b) -> a -> b
$ FastString -> String
unpackFS FastString
str of
      [String
ext_name] -> (Synchronicity
Async, String
ext_name)
      [String
ext_name, String
"sync"] -> (Synchronicity
Sync, String
ext_name)
      [String]
_ -> String -> (Synchronicity, String)
forall a. HasCallStack => String -> a
panic String
"dsWasmJSExport: unrecognized label string"

dsWasmJSExport' ::
  Synchronicity ->
  Maybe Id ->
  Coercion ->
  String ->
  DsM (CHeader, CStub, String, [Id], [Binding])
dsWasmJSExport' :: Synchronicity
-> Maybe Id
-> Coercion
-> String
-> DsM (CHeader, CStub, String, [Id], [Binding])
dsWasmJSExport' Synchronicity
sync Maybe Id
m_fn_id Coercion
co String
ext_name = do
  let ty :: Type
ty = HasDebugCallStack => Coercion -> Type
Coercion -> Type
coercionRKind Coercion
co
      ([Id]
_, Type
fun_ty) = Type -> ([Id], Type)
tcSplitForAllInvisTyVars Type
ty
      ([Scaled Type]
arg_tys, Type
orig_res_ty) = Type -> ([Scaled Type], Type)
tcSplitFunTys Type
fun_ty
      (Type
res_ty, Bool
is_io) = case Type -> Maybe (TyCon, Type)
tcSplitIOType_maybe Type
orig_res_ty of
        Just (TyCon
_, Type
res_ty) -> (Type
res_ty, Bool
True)
        Maybe (TyCon, Type)
Nothing -> (Type
orig_res_ty, Bool
False)
      res_ty_str :: String
res_ty_str = Type -> String
ffiType Type
res_ty
      top_handler_mod :: FastString
top_handler_mod = case Synchronicity
sync of
        Synchronicity
Sync -> FastString
"GHC.Internal.TopHandler"
        Synchronicity
Async -> FastString
"GHC.Internal.Wasm.Prim.Exports"
      top_handler_name :: String
top_handler_name
        | Bool
is_io = String
"runIO"
        | Bool
otherwise = String
"runNonIO"
  -- In case of sync export, we use the normal C FFI tophandler
  -- functions. They would call flushStdHandles in case of uncaught
  -- exception but not in normal cases, but we want flushStdHandles to
  -- be called so that there are less run-time surprises for users,
  -- and that's what our tophandler functions already do.
  --
  -- So for each sync export, we first wrap the computation with a C
  -- FFI tophandler, and then sequence it with flushStdHandles using
  -- (<*) :: IO a -> IO b -> IO a. But it's trickier to call (<*)
  -- using RTS API given type class dictionary is involved, so we'll
  -- just use finally.
  finally_id <-
    FastString -> String -> DsM Id
lookupGhcInternalVarId
      FastString
"GHC.Internal.Control.Exception.Base"
      String
"finally"
  flushStdHandles_id <-
    lookupGhcInternalVarId
      "GHC.Internal.TopHandler"
      "flushStdHandles"
  promiseRes_id <-
    lookupGhcInternalVarId "GHC.Internal.Wasm.Prim.Exports"
      $ "js_promiseResolve"
      ++ res_ty_str
  top_handler_id <- lookupGhcInternalVarId top_handler_mod top_handler_name
  let ppr_closure a
c = a -> SDoc
forall a. Outputable a => a -> SDoc
ppr a
c SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"_closure"
      mk_extern_closure_decl a
c =
        String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"extern StgClosure" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> a -> SDoc
forall a. Outputable a => a -> SDoc
ppr_closure a
c SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi
      gc_root_closures = Maybe Id -> [Id]
forall a. Maybe a -> [a]
maybeToList Maybe Id
m_fn_id [Id] -> [Id] -> [Id]
forall a. [a] -> [a] -> [a]
++ case Synchronicity
sync of
        -- In case of C FFI top handlers, they are already declared in
        -- RtsAPI.h and registered as GC roots in initBuiltinGcRoots.
        -- flushStdHandles is already registered but somehow the C
        -- stub can't access its declaration, won't hurt to declare it
        -- again here.
        Synchronicity
Sync -> [Id
finally_id, Id
flushStdHandles_id]
        Synchronicity
Async -> [Id
top_handler_id, Id
promiseRes_id]
      extern_closure_decls = [SDoc] -> SDoc
forall doc. IsDoc doc => [doc] -> doc
vcat ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall a b. (a -> b) -> a -> b
$ (Id -> SDoc) -> [Id] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map Id -> SDoc
forall a. Outputable a => a -> SDoc
mk_extern_closure_decl [Id]
gc_root_closures
      cstub_attr =
        String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"__attribute__"
          SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens
            (SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$ String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"export_name" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens (SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
doubleQuotes (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$ String -> SDoc
forall doc. IsLine doc => String -> doc
text String
ext_name))
      cstub_arg_list =
        [ String -> SDoc
forall doc. IsLine doc => String -> doc
text (String
"Hs" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
ffiType (Scaled Type -> Type
forall a. Scaled a -> a
scaledThing Scaled Type
arg_ty)) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'a' SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> Int -> SDoc
forall doc. IsLine doc => Int -> doc
int Int
i
        | (Int
i, Scaled Type
arg_ty) <- [Int] -> [Scaled Type] -> [(Int, Scaled Type)]
forall a b. [a] -> [b] -> [(a, b)]
zip [Int
1 ..] [Scaled Type]
arg_tys
        ]
      cstub_args = case [SDoc]
cstub_arg_list of
        [] -> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"void"
        [SDoc]
_ -> [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
hsep ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall a b. (a -> b) -> a -> b
$ SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma [SDoc]
cstub_arg_list
      cstub_proto
        | Synchronicity
Sync <- Synchronicity
sync,
          Type
res_ty HasCallStack => Type -> Type -> Bool
Type -> Type -> Bool
`eqType` Type
unitTy =
            String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"void" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
ext_name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens SDoc
cstub_args
        | Synchronicity
Sync <- Synchronicity
sync =
            String -> SDoc
forall doc. IsLine doc => String -> doc
text (String
"Hs" String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
res_ty_str) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
ext_name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens SDoc
cstub_args
        | Synchronicity
Async <- Synchronicity
sync =
            String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"HsJSVal" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
ext_name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens SDoc
cstub_args
      c_closure a
c = Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'&' SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> a -> SDoc
forall a. Outputable a => a -> SDoc
ppr_closure a
c
      c_call String
fn [doc]
args = String -> doc
forall doc. IsLine doc => String -> doc
text String
fn doc -> doc -> doc
forall doc. IsLine doc => doc -> doc -> doc
<> doc -> doc
forall doc. IsLine doc => doc -> doc
parens ([doc] -> doc
forall doc. IsLine doc => [doc] -> doc
hsep ([doc] -> doc) -> [doc] -> doc
forall a b. (a -> b) -> a -> b
$ doc -> [doc] -> [doc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate doc
forall doc. IsLine doc => doc
comma [doc]
args)
      c_rts_apply =
        (SDoc -> SDoc -> SDoc) -> [SDoc] -> SDoc
forall a. HasCallStack => (a -> a -> a) -> [a] -> a
Data.List.foldl1' ((SDoc -> SDoc -> SDoc) -> [SDoc] -> SDoc)
-> (SDoc -> SDoc -> SDoc) -> [SDoc] -> SDoc
forall a b. (a -> b) -> a -> b
$ \SDoc
fn SDoc
arg -> String -> [SDoc] -> SDoc
forall {doc}. IsLine doc => String -> [doc] -> doc
c_call String
"rts_apply" [String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"cap", SDoc
fn, SDoc
arg]
      apply_top_handler SDoc
expr = case Synchronicity
sync of
        Synchronicity
Sync ->
          [SDoc] -> SDoc
c_rts_apply
            [ Id -> SDoc
forall a. Outputable a => a -> SDoc
c_closure Id
finally_id,
              [SDoc] -> SDoc
c_rts_apply [Id -> SDoc
forall a. Outputable a => a -> SDoc
c_closure Id
top_handler_id, SDoc
expr],
              Id -> SDoc
forall a. Outputable a => a -> SDoc
c_closure Id
flushStdHandles_id
            ]
        Synchronicity
Async ->
          [SDoc] -> SDoc
c_rts_apply [Id -> SDoc
forall a. Outputable a => a -> SDoc
c_closure Id
top_handler_id, Id -> SDoc
forall a. Outputable a => a -> SDoc
c_closure Id
promiseRes_id, SDoc
expr]
      cstub_ret
        | Synchronicity
Sync <- Synchronicity
sync, Type
res_ty HasCallStack => Type -> Type -> Bool
Type -> Type -> Bool
`eqType` Type
unitTy = SDoc
forall doc. IsOutput doc => doc
empty
        | Synchronicity
Sync <- Synchronicity
sync = String -> SDoc
forall doc. IsLine doc => String -> doc
text (String -> SDoc) -> String -> SDoc
forall a b. (a -> b) -> a -> b
$ String
"return rts_get" String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
res_ty_str String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
"(ret);"
        | Synchronicity
Async <- Synchronicity
sync = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"return rts_getJSVal(ret);"
      (cstub_target, real_args)
        | Just fn_id <- m_fn_id = (c_closure fn_id, zip [1 ..] arg_tys)
        | otherwise = (text "(HaskellObj)deRefStablePtr(a1)", zip [2 ..] $ tail arg_tys)
      cstub_body =
        [SDoc] -> SDoc
forall doc. IsDoc doc => [doc] -> doc
vcat
          [ SDoc
forall doc. IsLine doc => doc
lbrace,
            String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"Capability *cap = rts_lock();",
            String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"HaskellObj ret;",
            String -> [SDoc] -> SDoc
forall {doc}. IsLine doc => String -> [doc] -> doc
c_call
              String
"rts_inCall"
              [ String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"&cap",
                SDoc -> SDoc
apply_top_handler
                  (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$ [SDoc] -> SDoc
c_rts_apply
                  ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall a b. (a -> b) -> a -> b
$ SDoc
cstub_target
                  SDoc -> [SDoc] -> [SDoc]
forall a. a -> [a] -> [a]
: [ String -> [SDoc] -> SDoc
forall {doc}. IsLine doc => String -> [doc] -> doc
c_call
                        (String
"rts_mk" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
ffiType (Scaled Type -> Type
forall a. Scaled a -> a
scaledThing Scaled Type
arg_ty))
                        [String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"cap", Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'a' SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> Int -> SDoc
forall doc. IsLine doc => Int -> doc
int Int
i]
                    | (Int
i, Scaled Type
arg_ty) <- [(Int, Scaled Type)]
real_args
                    ],
                String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"&ret"
              ]
              SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi,
            String -> [SDoc] -> SDoc
forall {doc}. IsLine doc => String -> [doc] -> doc
c_call String
"rts_checkSchedStatus" [SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
doubleQuotes (String -> SDoc
forall doc. IsLine doc => String -> doc
text String
ext_name), String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"cap"]
              SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
semi,
            String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"rts_unlock(cap);",
            SDoc
cstub_ret,
            SDoc
forall doc. IsLine doc => doc
rbrace
          ]
      cstub =
        SDoc
commonCDecls
          SDoc -> SDoc -> SDoc
$+$ SDoc
extern_closure_decls
          SDoc -> SDoc -> SDoc
$+$ SDoc
cstub_attr
          SDoc -> SDoc -> SDoc
$+$ SDoc
cstub_proto
          SDoc -> SDoc -> SDoc
$+$ SDoc
cstub_body
  pure (CHeader commonCDecls, CStub cstub [] [], "", gc_root_closures, [])

lookupGhcInternalVarId :: FastString -> String -> DsM Id
lookupGhcInternalVarId :: FastString -> String -> DsM Id
lookupGhcInternalVarId FastString
m String
v = do
  n <- Module -> OccName -> TcRnIf DsGblEnv DsLclEnv Name
forall a b. Module -> OccName -> TcRnIf a b Name
lookupOrig (FastString -> Module
mkGhcInternalModule FastString
m) (String -> OccName
mkVarOcc String
v)
  dsLookupGlobalId n

lookupGhcInternalTyCon :: FastString -> String -> DsM TyCon
lookupGhcInternalTyCon :: FastString -> String -> DsM TyCon
lookupGhcInternalTyCon FastString
m String
t = do
  n <- Module -> OccName -> TcRnIf DsGblEnv DsLclEnv Name
forall a b. Module -> OccName -> TcRnIf a b Name
lookupOrig (FastString -> Module
mkGhcInternalModule FastString
m) (String -> OccName
mkTcOcc String
t)
  dsLookupTyCon n

ffiType :: Type -> String
ffiType :: Type -> String
ffiType = OccName -> String
occNameString (OccName -> String) -> (Type -> OccName) -> Type -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TyCon -> OccName
forall a. NamedThing a => a -> OccName
getOccName (TyCon -> OccName) -> (Type -> TyCon) -> Type -> OccName
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (TyCon, [Type]) -> TyCon
forall a b. (a, b) -> a
fst ((TyCon, [Type]) -> TyCon)
-> (Type -> (TyCon, [Type])) -> Type -> TyCon
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Type -> (TyCon, [Type])
splitTyConApp

commonCDecls :: SDoc
commonCDecls :: SDoc
commonCDecls =
  [SDoc] -> SDoc
forall doc. IsDoc doc => [doc] -> doc
vcat
    [ String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"typedef __externref_t HsJSVal;",
      String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"HsJSVal rts_getJSVal(HaskellObj);",
      String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"HaskellObj rts_mkJSVal(Capability*, HsJSVal);"
    ]