Simplify promise event on throw handling.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/991833002

Cr-Commit-Position: refs/heads/master@{#27074}

src/isolate.cc

@@ -1555,14 +1555,9 @@ Handle<Object> Isolate::GetPromiseOnStackOnThrow() {
   StackHandler* promise_try = tltop->promise_on_stack_->handler();
   // Find the top-most try-catch handler.
   StackHandler* handler = StackHandler::FromAddress(Isolate::handler(tltop));
-  do {
-    if (handler == promise_try) {
-      return tltop->promise_on_stack_->promise();
-    }
-    handler = handler->next();
-    // Throwing inside a Promise can be intercepted by an inner try-catch, so
-    // we stop at the first try-catch handler.
-  } while (handler != NULL && !handler->is_catch());
+  // Throwing inside a Promise only leads to a reject if not caught by an inner
+  // try-catch or try-finally.
+  if (handler == promise_try) return tltop->promise_on_stack_->promise();
   return undefined;
 }
 

test/mjsunit/es6/debug-promises/resolve-after-aborted-try-finally.js

+// 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.
+
+// Flags: --expose-debug-as debug --allow-natives-syntax
+
+// Test debug events when we listen to all exceptions and
+// there is a catch handler for the exception thrown in a Promise.
+// We expect a normal Exception debug event to be triggered.
+
+Debug = debug.Debug;
+
+var events = [];
+
+function listener(event, exec_state, event_data, data) {
+  if (event == Debug.DebugEvent.PromiseEvent) events.push(event_data.status());
+}
+
+Debug.setListener(listener);
+
+var p = new Promise(function(resolve, reject) {
+  do {
+    try {
+      throw new Error("reject");
+    } finally {
+      break;  // No rethrow.
+    }
+  } while (false);
+  resolve();
+});
+
+assertEquals([0 /* create */, 1 /* resolve */], events);

test/mjsunit/es6/debug-promises/resolve-after-try-catch.js

+// 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.
+
+// Flags: --expose-debug-as debug --allow-natives-syntax
+
+// Test debug events when we listen to all exceptions and
+// there is a catch handler for the exception thrown in a Promise.
+// We expect a normal Exception debug event to be triggered.
+
+Debug = debug.Debug;
+
+var events = [];
+
+function listener(event, exec_state, event_data, data) {
+  if (event == Debug.DebugEvent.PromiseEvent) events.push(event_data.status());
+}
+
+Debug.setListener(listener);
+
+var p = new Promise(function (resolve, reject) {
+  try {
+    throw new Error("reject");
+  } catch (e) {
+  }
+  resolve();
+});
+
+assertEquals([0 /* create */, 1 /* resolve */], events);

test/mjsunit/es6/debug-promises/rethrow-in-try-finally.js

+// 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.
+
+// Flags: --expose-debug-as debug --allow-natives-syntax
+
+// Test debug events when we listen to all exceptions and
+// there is a catch handler for the exception thrown in a Promise.
+// We expect a normal Exception debug event to be triggered.
+
+Debug = debug.Debug;
+
+var events = [];
+
+function listener(event, exec_state, event_data, data) {
+  if (event == Debug.DebugEvent.PromiseEvent) events.push(event_data.status());
+}
+
+Debug.setListener(listener);
+
+var p = new Promise(function(resolve, reject) {
+  try {
+    throw new Error("reject");
+  } finally {
+    // Implicit rethrow.
+  }
+  resolve();
+});
+
+assertEquals([0 /* create */, -1 /* rethrown */], events);