[wasm] Add Suspender.suspendOnReturnedPromise

- Add Suspender.suspendOnReturnedPromise method
- Extend the WasmApiFunctionRef data with the suspender
- Detect wrapped WasmJSFunctions when we resolve the import

For now the generated wrapper is still a regular wasm-to-js wrapper, but
this sets the ground for generating specific wrappers for functions
wrapped by suspendOnReturnedPromise, and to access the suspender from
the wrapper code.

R=ahaas@chromium.org
CC=​fgm@chromium.org

Bug: v8:12191
Change-Id: I81cbec6b023507e47e6e1463b5f9b912f807da6a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3345000Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78560}

src/compiler/wasm-compiler.cc

@@ -7579,46 +7579,48 @@ std::unique_ptr<OptimizedCompilationJob> NewJSToWasmCompilationJob(
       std::move(debug_name), WasmAssemblerOptions());
 }
 
-std::pair<WasmImportCallKind, Handle<JSReceiver>> ResolveWasmImportCall(
+WasmImportData ResolveWasmImportCall(
     Handle<JSReceiver> callable, const wasm::FunctionSig* expected_sig,
     const wasm::WasmModule* module,
     const wasm::WasmFeatures& enabled_features) {
+  Isolate* isolate = callable->GetIsolate();
+  Handle<HeapObject> no_suspender;
   if (WasmExportedFunction::IsWasmExportedFunction(*callable)) {
     auto imported_function = Handle<WasmExportedFunction>::cast(callable);
     if (!imported_function->MatchesSignature(module, expected_sig)) {
-      return std::make_pair(WasmImportCallKind::kLinkError, callable);
+      return {WasmImportCallKind::kLinkError, callable, no_suspender};
     }
     uint32_t func_index =
         static_cast<uint32_t>(imported_function->function_index());
     if (func_index >=
         imported_function->instance().module()->num_imported_functions) {
-      return std::make_pair(WasmImportCallKind::kWasmToWasm, callable);
+      return {WasmImportCallKind::kWasmToWasm, callable, no_suspender};
     }
-    Isolate* isolate = callable->GetIsolate();
     // Resolve the shortcut to the underlying callable and continue.
     Handle<WasmInstanceObject> instance(imported_function->instance(), isolate);
     ImportedFunctionEntry entry(instance, func_index);
     callable = handle(entry.callable(), isolate);
   }
+  Handle<HeapObject> suspender = isolate->factory()->undefined_value();
   if (WasmJSFunction::IsWasmJSFunction(*callable)) {
     auto js_function = Handle<WasmJSFunction>::cast(callable);
     if (!js_function->MatchesSignature(expected_sig)) {
-      return std::make_pair(WasmImportCallKind::kLinkError, callable);
+      return {WasmImportCallKind::kLinkError, callable, no_suspender};
     }
-    Isolate* isolate = callable->GetIsolate();
+    suspender = handle(js_function->GetSuspender(), isolate);
     // Resolve the short-cut to the underlying callable and continue.
     callable = handle(js_function->GetCallable(), isolate);
   }
   if (WasmCapiFunction::IsWasmCapiFunction(*callable)) {
     auto capi_function = Handle<WasmCapiFunction>::cast(callable);
     if (!capi_function->MatchesSignature(expected_sig)) {
-      return std::make_pair(WasmImportCallKind::kLinkError, callable);
+      return {WasmImportCallKind::kLinkError, callable, no_suspender};
     }
-    return std::make_pair(WasmImportCallKind::kWasmToCapi, callable);
+    return {WasmImportCallKind::kWasmToCapi, callable, no_suspender};
   }
   // Assuming we are calling to JS, check whether this would be a runtime error.
   if (!wasm::IsJSCompatibleSignature(expected_sig, module, enabled_features)) {
-    return std::make_pair(WasmImportCallKind::kRuntimeTypeError, callable);
+    return {WasmImportCallKind::kRuntimeTypeError, callable, no_suspender};
   }
   // For JavaScript calls, determine whether the target has an arity match.
   if (callable->IsJSFunction()) {
@@ -7634,7 +7636,7 @@ std::pair<WasmImportCallKind, Handle<JSReceiver>> ResolveWasmImportCall(
     if (!sig) sig = wasm::WasmOpcodes::AsmjsSignature(wasm::kExpr##name); \
     DCHECK_NOT_NULL(sig);                                                 \
     if (*expected_sig == *sig) {                                          \
-      return std::make_pair(WasmImportCallKind::k##name, callable);       \
+      return {WasmImportCallKind::k##name, callable, no_suspender};       \
     }                                                                     \
   }
 #define COMPARE_SIG_FOR_BUILTIN_F64(name) \
@@ -7679,13 +7681,12 @@ std::pair<WasmImportCallKind, Handle<JSReceiver>> ResolveWasmImportCall(
 
     if (IsClassConstructor(shared->kind())) {
       // Class constructor will throw anyway.
-      return std::make_pair(WasmImportCallKind::kUseCallBuiltin, callable);
+      return {WasmImportCallKind::kUseCallBuiltin, callable, suspender};
     }
 
     if (shared->internal_formal_parameter_count_without_receiver() ==
         expected_sig->parameter_count()) {
-      return std::make_pair(WasmImportCallKind::kJSFunctionArityMatch,
-                            callable);
+      return {WasmImportCallKind::kJSFunctionArityMatch, callable, suspender};
     }
 
     // If function isn't compiled, compile it now.
@@ -7696,11 +7697,10 @@ std::pair<WasmImportCallKind, Handle<JSReceiver>> ResolveWasmImportCall(
                         &is_compiled_scope);
     }
 
-    return std::make_pair(WasmImportCallKind::kJSFunctionArityMismatch,
-                          callable);
+    return {WasmImportCallKind::kJSFunctionArityMismatch, callable, suspender};
   }
   // Unknown case. Use the call builtin.
-  return std::make_pair(WasmImportCallKind::kUseCallBuiltin, callable);
+  return {WasmImportCallKind::kUseCallBuiltin, callable, suspender};
 }
 
 namespace {

src/compiler/wasm-compiler.h

@@ -107,14 +107,19 @@ enum class WasmImportCallKind : uint8_t {
 constexpr WasmImportCallKind kDefaultImportCallKind =
     WasmImportCallKind::kJSFunctionArityMatch;
 
+struct WasmImportData {
+  WasmImportCallKind kind;
+  Handle<JSReceiver> callable;
+  Handle<HeapObject> suspender;
+};
 // Resolves which import call wrapper is required for the given JS callable.
-// Returns the kind of wrapper need and the ultimate target callable. Note that
-// some callables (e.g. a {WasmExportedFunction} or {WasmJSFunction}) just wrap
-// another target, which is why the ultimate target is returned as well.
-V8_EXPORT_PRIVATE std::pair<WasmImportCallKind, Handle<JSReceiver>>
-ResolveWasmImportCall(Handle<JSReceiver> callable, const wasm::FunctionSig* sig,
-                      const wasm::WasmModule* module,
-                      const wasm::WasmFeatures& enabled_features);
+// Returns the kind of wrapper needed, the ultimate target callable, and the
+// suspender object if applicable. Note that some callables (e.g. a
+// {WasmExportedFunction} or {WasmJSFunction}) just wrap another target, which
+// is why the ultimate target is returned as well.
+V8_EXPORT_PRIVATE WasmImportData ResolveWasmImportCall(
+    Handle<JSReceiver> callable, const wasm::FunctionSig* sig,
+    const wasm::WasmModule* module, const wasm::WasmFeatures& enabled_features);
 
 // Compiles an import call wrapper, which allows Wasm to call imports.
 V8_EXPORT_PRIVATE wasm::WasmCompilationResult CompileWasmImportCallWrapper(

src/diagnostics/objects-printer.cc

@@ -1946,6 +1946,7 @@ void WasmApiFunctionRef::WasmApiFunctionRefPrint(std::ostream& os) {
   os << "\n - isolate_root: " << reinterpret_cast<void*>(isolate_root());
   os << "\n - native_context: " << Brief(native_context());
   os << "\n - callable: " << Brief(callable());
+  os << "\n - suspender: " << Brief(suspender());
   os << "\n";
 }
 

src/heap/factory.cc

@@ -1523,7 +1523,7 @@ Handle<WasmTypeInfo> Factory::NewWasmTypeInfo(
 }
 
 Handle<WasmApiFunctionRef> Factory::NewWasmApiFunctionRef(
-    Handle<JSReceiver> callable) {
+    Handle<JSReceiver> callable, Handle<HeapObject> suspender) {
   Map map = *wasm_api_function_ref_map();
   auto result = WasmApiFunctionRef::cast(AllocateRawWithImmortalMap(
       map.instance_size(), AllocationType::kOld, map));
@@ -1535,6 +1535,11 @@ Handle<WasmApiFunctionRef> Factory::NewWasmApiFunctionRef(
   } else {
     result.set_callable(*undefined_value());
   }
+  if (!suspender.is_null()) {
+    result.set_suspender(*suspender);
+  } else {
+    result.set_suspender(*undefined_value());
+  }
   return handle(result, isolate());
 }
 
@@ -1556,8 +1561,8 @@ Handle<WasmInternalFunction> Factory::NewWasmInternalFunction(
 Handle<WasmJSFunctionData> Factory::NewWasmJSFunctionData(
     Address opt_call_target, Handle<JSReceiver> callable, int return_count,
     int parameter_count, Handle<PodArray<wasm::ValueType>> serialized_sig,
-    Handle<CodeT> wrapper_code, Handle<Map> rtt) {
-  Handle<WasmApiFunctionRef> ref = NewWasmApiFunctionRef(callable);
+    Handle<CodeT> wrapper_code, Handle<Map> rtt, Handle<HeapObject> suspender) {
+  Handle<WasmApiFunctionRef> ref = NewWasmApiFunctionRef(callable, suspender);
   Handle<WasmInternalFunction> internal =
       NewWasmInternalFunction(opt_call_target, ref, rtt);
   Map map = *wasm_js_function_data_map();
@@ -1602,7 +1607,8 @@ Handle<WasmCapiFunctionData> Factory::NewWasmCapiFunctionData(
     Address call_target, Handle<Foreign> embedder_data,
     Handle<CodeT> wrapper_code, Handle<Map> rtt,
     Handle<PodArray<wasm::ValueType>> serialized_sig) {
-  Handle<WasmApiFunctionRef> ref = NewWasmApiFunctionRef(Handle<JSReceiver>());
+  Handle<WasmApiFunctionRef> ref =
+      NewWasmApiFunctionRef(Handle<JSReceiver>(), Handle<HeapObject>());
   Handle<WasmInternalFunction> internal =
       NewWasmInternalFunction(call_target, ref, rtt);
   Map map = *wasm_capi_function_data_map();

src/heap/factory.h

@@ -604,13 +604,15 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
       Handle<CodeT> export_wrapper, Handle<WasmInstanceObject> instance,
       Address call_target, Handle<Object> ref, int func_index,
       Address sig_address, int wrapper_budget, Handle<Map> rtt);
-  Handle<WasmApiFunctionRef> NewWasmApiFunctionRef(Handle<JSReceiver> callable);
+  Handle<WasmApiFunctionRef> NewWasmApiFunctionRef(
+      Handle<JSReceiver> callable, Handle<HeapObject> suspender);
   // {opt_call_target} is kNullAddress for JavaScript functions, and
   // non-null for exported Wasm functions.
   Handle<WasmJSFunctionData> NewWasmJSFunctionData(
       Address opt_call_target, Handle<JSReceiver> callable, int return_count,
       int parameter_count, Handle<PodArray<wasm::ValueType>> serialized_sig,
-      Handle<CodeT> wrapper_code, Handle<Map> rtt);
+      Handle<CodeT> wrapper_code, Handle<Map> rtt,
+      Handle<HeapObject> suspender);
   Handle<WasmStruct> NewWasmStruct(const wasm::StructType* type,
                                    wasm::WasmValue* args, Handle<Map> map);
   Handle<WasmArray> NewWasmArray(const wasm::ArrayType* type,

src/wasm/module-instantiate.cc

@@ -1181,8 +1181,8 @@ bool InstanceBuilder::ProcessImportedFunction(
   const FunctionSig* expected_sig = module_->functions[func_index].sig;
   auto resolved = compiler::ResolveWasmImportCall(js_receiver, expected_sig,
                                                   module_, enabled_);
-  compiler::WasmImportCallKind kind = resolved.first;
-  js_receiver = resolved.second;
+  compiler::WasmImportCallKind kind = resolved.kind;
+  js_receiver = resolved.callable;
   switch (kind) {
     case compiler::WasmImportCallKind::kLinkError:
       ReportLinkError("imported function does not match the expected type",
@@ -1224,7 +1224,8 @@ bool InstanceBuilder::ProcessImportedFunction(
       ImportedFunctionEntry entry(instance, func_index);
       // We re-use the SetWasmToJs infrastructure because it passes the
       // callable to the wrapper, which we need to get the function data.
-      entry.SetWasmToJs(isolate_, js_receiver, wasm_code);
+      entry.SetWasmToJs(isolate_, js_receiver, wasm_code,
+                        isolate_->factory()->undefined_value());
       break;
     }
     default: {
@@ -1245,7 +1246,7 @@ bool InstanceBuilder::ProcessImportedFunction(
       ImportedFunctionEntry entry(instance, func_index);
       if (wasm_code->kind() == WasmCode::kWasmToJsWrapper) {
         // Wasm to JS wrappers are treated specially in the import table.
-        entry.SetWasmToJs(isolate_, js_receiver, wasm_code);
+        entry.SetWasmToJs(isolate_, js_receiver, wasm_code, resolved.suspender);
       } else {
         // Wasm math intrinsics are compiled as regular Wasm functions.
         DCHECK(kind >= compiler::WasmImportCallKind::kFirstMathIntrinsic &&
@@ -1634,7 +1635,7 @@ void InstanceBuilder::CompileImportWrappers(
     const FunctionSig* sig = module_->functions[func_index].sig;
     auto resolved =
         compiler::ResolveWasmImportCall(js_receiver, sig, module_, enabled_);
-    compiler::WasmImportCallKind kind = resolved.first;
+    compiler::WasmImportCallKind kind = resolved.kind;
     if (kind == compiler::WasmImportCallKind::kWasmToWasm ||
         kind == compiler::WasmImportCallKind::kLinkError ||
         kind == compiler::WasmImportCallKind::kWasmToCapi) {
@@ -1642,9 +1643,9 @@ void InstanceBuilder::CompileImportWrappers(
     }
 
     int expected_arity = static_cast<int>(sig->parameter_count());
-    if (resolved.first ==
+    if (resolved.kind ==
         compiler::WasmImportCallKind::kJSFunctionArityMismatch) {
-      Handle<JSFunction> function = Handle<JSFunction>::cast(resolved.second);
+      Handle<JSFunction> function = Handle<JSFunction>::cast(resolved.callable);
       SharedFunctionInfo shared = function->shared();
       expected_arity =
           shared.internal_formal_parameter_count_without_receiver();

src/wasm/wasm-js.cc

@@ -25,9 +25,11 @@
 #include "src/init/v8.h"
 #include "src/objects/fixed-array.h"
 #include "src/objects/instance-type.h"
+#include "src/objects/js-function.h"
 #include "src/objects/js-promise-inl.h"
 #include "src/objects/managed-inl.h"
 #include "src/objects/objects-inl.h"
+#include "src/objects/shared-function-info.h"
 #include "src/objects/templates.h"
 #include "src/parsing/parse-info.h"
 #include "src/tasks/task-utils.h"
@@ -1894,8 +1896,10 @@ void WebAssemblyFunction(const v8::FunctionCallbackInfo<v8::Value>& args) {
     return;
   }
 
+  i::Handle<i::HeapObject> suspender =
+      handle(i::ReadOnlyRoots(i_isolate).undefined_value(), i_isolate);
   i::Handle<i::JSFunction> result =
-      i::WasmJSFunction::New(i_isolate, sig, callable);
+      i::WasmJSFunction::New(i_isolate, sig, callable, suspender);
   args.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
@@ -1925,6 +1929,7 @@ void WebAssemblyFunctionType(const v8::FunctionCallbackInfo<v8::Value>& args) {
 constexpr const char* kName_WasmGlobalObject = "WebAssembly.Global";
 constexpr const char* kName_WasmMemoryObject = "WebAssembly.Memory";
 constexpr const char* kName_WasmInstanceObject = "WebAssembly.Instance";
+constexpr const char* kName_WasmSuspenderObject = "WebAssembly.Suspender";
 constexpr const char* kName_WasmTableObject = "WebAssembly.Table";
 constexpr const char* kName_WasmTagObject = "WebAssembly.Tag";
 constexpr const char* kName_WasmExceptionPackage = "WebAssembly.Exception";
@@ -2580,6 +2585,38 @@ void WebAssemblySuspenderReturnPromiseOnSuspend(
   args.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
+// WebAssembly.Suspender.suspendOnReturnedPromise(Function) -> Function
+void WebAssemblySuspenderSuspendOnReturnedPromise(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  HandleScope scope(isolate);
+  ScheduledErrorThrower thrower(
+      i_isolate, "WebAssembly.Suspender.suspendOnReturnedPromise()");
+  if (!args[0]->IsObject()) {
+    thrower.TypeError("Argument 0 must be a WebAssembly.Function");
+    return;
+  }
+  i::Zone zone(i_isolate->allocator(), ZONE_NAME);
+  const i::wasm::FunctionSig* sig;
+  i::Handle<i::Object> arg0 = Utils::OpenHandle(*args[0]);
+
+  if (i::WasmExportedFunction::IsWasmExportedFunction(*arg0)) {
+    // TODO(thibaudm): Suspend on wrapped wasm-to-wasm calls too.
+    UNIMPLEMENTED();
+  } else if (!i::WasmJSFunction::IsWasmJSFunction(*arg0)) {
+    thrower.TypeError("Argument 0 must be a WebAssembly.Function");
+    return;
+  }
+  sig = i::Handle<i::WasmJSFunction>::cast(arg0)->GetSignature(&zone);
+
+  auto callable = handle(
+      i::Handle<i::WasmJSFunction>::cast(arg0)->GetCallable(), i_isolate);
+  EXTRACT_THIS(suspender, WasmSuspenderObject);
+  i::Handle<i::JSFunction> result =
+      i::WasmJSFunction::New(i_isolate, sig, callable, suspender);
+  args.GetReturnValue().Set(Utils::ToLocal(result));
+}
 }  // namespace
 
 // TODO(titzer): we use the API to create the function template because the
@@ -2876,6 +2913,8 @@ void WasmJs::Install(Isolate* isolate, bool exposed_on_global_object) {
         WasmSuspenderObject::kHeaderSize, "WebAssembly.Suspender");
     InstallFunc(isolate, suspender_proto, "returnPromiseOnSuspend",
                 WebAssemblySuspenderReturnPromiseOnSuspend, 1);
+    InstallFunc(isolate, suspender_proto, "suspendOnReturnedPromise",
+                WebAssemblySuspenderSuspendOnReturnedPromise, 1);
   }
 
   // Setup Function

src/wasm/wasm-objects.cc

@@ -1076,7 +1076,7 @@ FunctionTargetAndRef::FunctionTargetAndRef(
 
 void ImportedFunctionEntry::SetWasmToJs(
     Isolate* isolate, Handle<JSReceiver> callable,
-    const wasm::WasmCode* wasm_to_js_wrapper) {
+    const wasm::WasmCode* wasm_to_js_wrapper, Handle<HeapObject> suspender) {
   TRACE_IFT("Import callable 0x%" PRIxPTR "[%d] = {callable=0x%" PRIxPTR
             ", target=%p}\n",
             instance_->ptr(), index_, callable->ptr(),
@@ -1084,7 +1084,7 @@ void ImportedFunctionEntry::SetWasmToJs(
   DCHECK(wasm_to_js_wrapper->kind() == wasm::WasmCode::kWasmToJsWrapper ||
          wasm_to_js_wrapper->kind() == wasm::WasmCode::kWasmToCapiWrapper);
   Handle<WasmApiFunctionRef> ref =
-      isolate->factory()->NewWasmApiFunctionRef(callable);
+      isolate->factory()->NewWasmApiFunctionRef(callable, suspender);
   instance_->imported_function_refs().set(index_, *ref);
   instance_->imported_function_targets()[index_] =
       wasm_to_js_wrapper->instruction_start();
@@ -1448,8 +1448,8 @@ void WasmInstanceObject::ImportWasmJSFunctionIntoTable(
     const wasm::WasmFeatures enabled = native_module->enabled_features();
     auto resolved = compiler::ResolveWasmImportCall(
         callable, sig, instance->module(), enabled);
-    compiler::WasmImportCallKind kind = resolved.first;
-    callable = resolved.second;  // Update to ultimate target.
+    compiler::WasmImportCallKind kind = resolved.kind;
+    callable = resolved.callable;  // Update to ultimate target.
     DCHECK_NE(compiler::WasmImportCallKind::kLinkError, kind);
     wasm::CompilationEnv env = native_module->CreateCompilationEnv();
     // {expected_arity} should only be used if kind != kJSFunctionArityMismatch.
@@ -1479,8 +1479,9 @@ void WasmInstanceObject::ImportWasmJSFunctionIntoTable(
   }
 
   // Update the dispatch table.
+  Handle<HeapObject> suspender = handle(js_function->GetSuspender(), isolate);
   Handle<WasmApiFunctionRef> ref =
-      isolate->factory()->NewWasmApiFunctionRef(callable);
+      isolate->factory()->NewWasmApiFunctionRef(callable, suspender);
   WasmIndirectFunctionTable::cast(
       instance->indirect_function_tables().get(table_index))
       .Set(entry_index, sig_id, call_target, *ref);
@@ -2031,7 +2032,8 @@ bool WasmJSFunction::IsWasmJSFunction(Object object) {
 
 Handle<WasmJSFunction> WasmJSFunction::New(Isolate* isolate,
                                            const wasm::FunctionSig* sig,
-                                           Handle<JSReceiver> callable) {
+                                           Handle<JSReceiver> callable,
+                                           Handle<HeapObject> suspender) {
   DCHECK_LE(sig->all().size(), kMaxInt);
   int sig_size = static_cast<int>(sig->all().size());
   int return_count = static_cast<int>(sig->return_count());
@@ -2061,7 +2063,7 @@ Handle<WasmJSFunction> WasmJSFunction::New(Isolate* isolate,
   Handle<Map> rtt = factory->wasm_internal_function_map();
   Handle<WasmJSFunctionData> function_data = factory->NewWasmJSFunctionData(
       call_target, callable, return_count, parameter_count, serialized_sig,
-      wrapper_code, rtt);
+      wrapper_code, rtt, suspender);
 
   if (wasm::WasmFeatures::FromIsolate(isolate).has_typed_funcref()) {
     using CK = compiler::WasmImportCallKind;
@@ -2108,6 +2110,12 @@ JSReceiver WasmJSFunction::GetCallable() const {
                               .callable());
 }
 
+HeapObject WasmJSFunction::GetSuspender() const {
+  return WasmApiFunctionRef::cast(
+             shared().wasm_js_function_data().internal().ref())
+      .suspender();
+}
+
 const wasm::FunctionSig* WasmJSFunction::GetSignature(Zone* zone) {
   WasmJSFunctionData function_data = shared().wasm_js_function_data();
   int sig_size = function_data.serialized_signature().length();

src/wasm/wasm-objects.h

@@ -91,7 +91,8 @@ class ImportedFunctionEntry {
   // Initialize this entry as a Wasm to JS call. This accepts the isolate as a
   // parameter, since it must allocate a tuple.
   V8_EXPORT_PRIVATE void SetWasmToJs(Isolate*, Handle<JSReceiver> callable,
-                                     const wasm::WasmCode* wasm_to_js_wrapper);
+                                     const wasm::WasmCode* wasm_to_js_wrapper,
+                                     Handle<HeapObject> suspender);
   // Initialize this entry as a Wasm to Wasm call.
   void SetWasmToWasm(WasmInstanceObject target_instance, Address call_target);
 
@@ -622,9 +623,11 @@ class WasmJSFunction : public JSFunction {
 
   static Handle<WasmJSFunction> New(Isolate* isolate,
                                     const wasm::FunctionSig* sig,
-                                    Handle<JSReceiver> callable);
+                                    Handle<JSReceiver> callable,
+                                    Handle<HeapObject> suspender);
 
   JSReceiver GetCallable() const;
+  HeapObject GetSuspender() const;
   // Deserializes the signature of this function using the provided zone. Note
   // that lifetime of the signature is hence directly coupled to the zone.
   const wasm::FunctionSig* GetSignature(Zone* zone);

src/wasm/wasm-objects.tq

@@ -21,6 +21,7 @@ extern class WasmApiFunctionRef extends HeapObject {
   isolate_root: RawPtr;
   native_context: NativeContext;
   callable: JSReceiver|Undefined;
+  suspender: WasmSuspenderObject|Undefined;
 }
 
 // This is the representation that is used internally by wasm to represent

test/cctest/wasm/wasm-run-utils.cc

@@ -73,8 +73,8 @@ TestingModuleBuilder::TestingModuleBuilder(
     auto resolved = compiler::ResolveWasmImportCall(
         maybe_import->js_function, maybe_import->sig,
         instance_object_->module(), enabled_features_);
-    compiler::WasmImportCallKind kind = resolved.first;
-    Handle<JSReceiver> callable = resolved.second;
+    compiler::WasmImportCallKind kind = resolved.kind;
+    Handle<JSReceiver> callable = resolved.callable;
     WasmImportWrapperCache::ModificationScope cache_scope(
         native_module_->import_wrapper_cache());
     WasmImportWrapperCache::CacheKey key(
@@ -89,7 +89,7 @@ TestingModuleBuilder::TestingModuleBuilder(
     }
 
     ImportedFunctionEntry(instance_object_, maybe_import_index)
-        .SetWasmToJs(isolate_, callable, import_wrapper);
+        .SetWasmToJs(isolate_, callable, import_wrapper, resolved.suspender);
   }
 
   if (tier == TestExecutionTier::kInterpreter) {

test/mjsunit/wasm/stack-switching.js

@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax --experimental-wasm-stack-switching --expose-gc
+// Flags: --allow-natives-syntax --experimental-wasm-stack-switching
+// Flags: --experimental-wasm-type-reflection --expose-gc
 
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
@@ -27,6 +28,31 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
   assertEquals(42, instance.exports.g.value);
 })();
 
+(function TestStackSwitchSuspend() {
+  print(arguments.callee.name);
+  let builder = new WasmModuleBuilder();
+  builder.addGlobal(kWasmI32, true).exportAs('g');
+  import_index = builder.addImport('m', 'import', kSig_i_v);
+  builder.addFunction("test", kSig_v_v)
+      .addBody([
+          kExprCallFunction, import_index, // suspend
+          kExprGlobalSet, 0 // resume
+      ]).exportFunc();
+  let suspender = new WebAssembly.Suspender();
+  function js_import() {
+    // TODO(thibaudm): Return the value as a promise.
+    return 42;
+  };
+  let wasm_js_import = new WebAssembly.Function({parameters: [], results: ['i32']}, js_import);
+  let suspending_wasm_js_import = suspender.suspendOnReturnedPromise(wasm_js_import);
+  let instance = builder.instantiate({m: {import: suspending_wasm_js_import}});
+  let wrapped_export = suspender.returnPromiseOnSuspend(instance.exports.test);
+  let combined_promise = wrapped_export();
+  // TODO(thibaudm): Once we generate the actual wrapper, we expect 0 here
+  // The global will only be set after the promise resolves.
+  assertEquals(42, instance.exports.g.value);
+})();
+
 (function TestStackSwitchGC() {
   print(arguments.callee.name);
   let builder = new WasmModuleBuilder();