Promises: Add is_silent flag and ignore rejects when it is set

This allows for marking promises as silent. Setting this flag prevents
the debugger from pausing when the promise rejects.

Bug: chromium:1132506
Change-Id: I260e52faa45ebedd9e8d84e092bd0260e828a902
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3001354Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75595}

AUTHORS

@@ -126,6 +126,7 @@ Jay Freeman <saurik@saurik.com>
 James Pike <g00gle@chilon.net>
 James M Snell <jasnell@gmail.com>
 Javad Amiri <javad.amiri@anu.edu.au>
+Jesper van den Ende <jespertheend@gmail.com>
 Ji Qiu <qiuji@iscas.ac.cn>
 Jianghua Yang <jianghua.yjh@alibaba-inc.com>
 Jiawen Geng <technicalcute@gmail.com>

include/v8.h

@@ -4908,6 +4908,12 @@ class V8_EXPORT Promise : public Object {
    */
   void MarkAsHandled();
 
+  /**
+   * Marks this promise as silent to prevent pausing the debugger when the
+   * promise is rejected.
+   */
+  void MarkAsSilent();
+
   V8_INLINE static Promise* Cast(Value* obj);
 
   static const int kEmbedderFieldCount = V8_PROMISE_INTERNAL_FIELD_COUNT;

src/api/api.cc

@@ -7482,6 +7482,11 @@ void Promise::MarkAsHandled() {
   js_promise->set_has_handler(true);
 }
 
+void Promise::MarkAsSilent() {
+  i::Handle<i::JSPromise> js_promise = Utils::OpenHandle(this);
+  js_promise->set_is_silent(true);
+}
+
 Local<Value> Proxy::GetTarget() {
   i::Handle<i::JSProxy> self = Utils::OpenHandle(this);
   i::Handle<i::Object> target(self->target(), self->GetIsolate());

src/builtins/promise-misc.tq

@@ -41,6 +41,7 @@ macro PromiseInit(promise: JSPromise): void {
     status: PromiseState::kPending,
     has_handler: false,
     handled_hint: false,
+    is_silent: false,
     async_task_id: 0
   });
   promise_internal::ZeroOutEmbedderOffsets(promise);
@@ -60,6 +61,7 @@ macro InnerNewJSPromise(implicit context: Context)(): JSPromise {
     status: PromiseState::kPending,
     has_handler: false,
     handled_hint: false,
+    is_silent: false,
     async_task_id: 0
   });
   return promise;

src/debug/debug.cc

@@ -2032,16 +2032,20 @@ void Debug::OnException(Handle<Object> exception, Handle<Object> promise,
 
   bool uncaught = catch_type == Isolate::NOT_CAUGHT;
   if (promise->IsJSObject()) {
-    Handle<JSObject> jspromise = Handle<JSObject>::cast(promise);
+    Handle<JSObject> jsobject = Handle<JSObject>::cast(promise);
     // Mark the promise as already having triggered a message.
     Handle<Symbol> key = isolate_->factory()->promise_debug_marker_symbol();
-    Object::SetProperty(isolate_, jspromise, key, key, StoreOrigin::kMaybeKeyed,
+    Object::SetProperty(isolate_, jsobject, key, key, StoreOrigin::kMaybeKeyed,
                         Just(ShouldThrow::kThrowOnError))
         .Assert();
     // Check whether the promise reject is considered an uncaught exception.
-    if (jspromise->IsJSPromise()) {
-      uncaught = !isolate_->PromiseHasUserDefinedRejectHandler(
-          Handle<JSPromise>::cast(jspromise));
+    if (jsobject->IsJSPromise()) {
+      Handle<JSPromise> jspromise = Handle<JSPromise>::cast(jsobject);
+
+      // Ignore the exception if the promise was marked as silent
+      if (jspromise->is_silent()) return;
+
+      uncaught = !isolate_->PromiseHasUserDefinedRejectHandler(jspromise);
     } else {
       uncaught = true;
     }

src/diagnostics/objects-printer.cc

@@ -676,6 +676,7 @@ void JSPromise::JSPromisePrint(std::ostream& os) {
   }
   os << "\n - has_handler: " << has_handler();
   os << "\n - handled_hint: " << handled_hint();
+  os << "\n - is_silent: " << is_silent();
   JSObjectPrintBody(os, *this);
 }
 

src/objects/js-promise-inl.h

@@ -22,6 +22,7 @@ TQ_OBJECT_CONSTRUCTORS_IMPL(JSPromise)
 
 BOOL_ACCESSORS(JSPromise, flags, has_handler, HasHandlerBit::kShift)
 BOOL_ACCESSORS(JSPromise, flags, handled_hint, HandledHintBit::kShift)
+BOOL_ACCESSORS(JSPromise, flags, is_silent, IsSilentBit::kShift)
 
 Object JSPromise::result() const {
   DCHECK_NE(Promise::kPending, status());

src/objects/js-promise.h

@@ -42,6 +42,10 @@ class JSPromise : public TorqueGeneratedJSPromise<JSPromise, JSObject> {
   // block in an async function.
   DECL_BOOLEAN_ACCESSORS(handled_hint)
 
+  // [is_silent]: Whether this promise should cause the debugger to pause when
+  // rejected.
+  DECL_BOOLEAN_ACCESSORS(is_silent)
+
   int async_task_id() const;
   void set_async_task_id(int id);
 

src/objects/js-promise.tq

@@ -6,6 +6,7 @@ bitfield struct JSPromiseFlags extends uint31 {
   status: PromiseState: 2 bit;
   has_handler: bool: 1 bit;
   handled_hint: bool: 1 bit;
+  is_silent: bool: 1 bit;
   async_task_id: int32: 22 bit;
 }