Async/await catch prediction for "the synchronous case"

src/runtime/runtime-internal.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <memory>
 
 #include "src/arguments.h"
 #include "src/ast/prettyprinter.h"
@@ skipping 256 matching lines @@
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
   Handle<String> type = Object::TypeOf(isolate, object);
   THROW_NEW_ERROR_RETURN_FAILURE(
       isolate, NewTypeError(MessageTemplate::kApplyNonFunction, object, type));
 }
 
 namespace {
 
 void PromiseRejectEvent(Isolate* isolate, Handle<JSObject> promise,
-                        Handle<JSObject> rejected_promise, Handle<Object> value,
+                        Handle<Object> rejected_promise, Handle<Object> value,
                         bool debug_event) {
   if (isolate->debug()->is_active() && debug_event) {
     isolate->debug()->OnPromiseReject(rejected_promise, value);
   }
   Handle<Symbol> key = isolate->factory()->promise_has_handler_symbol();
   // Do not report if we actually have a handler.
   if (JSReceiver::GetDataProperty(promise, key)->IsUndefined(isolate)) {
     isolate->ReportPromiseReject(promise, value,
                                  v8::kPromiseRejectWithNoHandler);
   }
 }
 
 }  // namespace
 
 RUNTIME_FUNCTION(Runtime_PromiseRejectEvent) {
   DCHECK(args.length() == 3);
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, promise, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
   CONVERT_BOOLEAN_ARG_CHECKED(debug_event, 2);
 
   PromiseRejectEvent(isolate, promise, promise, value, debug_event);
   return isolate->heap()->undefined_value();
 }
 
 RUNTIME_FUNCTION(Runtime_PromiseRejectEventFromStack) {

[jgruber, 2016/09/12 10:27:31]

Just as an aside, maybe we could move these to runtime-promise.cc at some point.

   DCHECK(args.length() == 2);
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, promise, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
 
-  Handle<JSObject> rejected_promise = promise;
+  Handle<Object> rejected_promise = promise;
   if (isolate->debug()->is_active()) {
-    Handle<Object> promise_on_stack = isolate->GetPromiseOnStackOnThrow();
-    if (promise_on_stack->IsJSObject()) {
-      rejected_promise = Handle<JSObject>::cast(promise_on_stack);
-    }
+    // If the Promise.reject call is caught, then this will return
+    // undefined, which will be interpreted by uncaught as being a
+    // caught exception event.
+    rejected_promise = isolate->GetPromiseOnStackOnThrow();
   }
   PromiseRejectEvent(isolate, promise, rejected_promise, value, true);
   return isolate->heap()->undefined_value();
 }
 
 RUNTIME_FUNCTION(Runtime_PromiseRevokeReject) {
   DCHECK(args.length() == 1);
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, promise, 0);
   Handle<Symbol> key = isolate->factory()->promise_has_handler_symbol();
@@ skipping 265 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_Typeof) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
   return *Object::TypeOf(isolate, object);
 }
 
 }  // namespace internal
 }  // namespace v8