Move catch prediction into frontend.

test/mjsunit/debug-exceptions.js

+// Copyright 2016 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
+
+
+Debug = debug.Debug
+
+let error = false;
+let uncaught;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Exception) return;
+  try {
+    uncaught = event_data.uncaught();
+  } catch (e) {
+    error = true;
+  }
+}
+
+Debug.setBreakOnException();
+Debug.setListener(listener);
+
+
+function assertCaught(f) {
+  try {f()} finally {
+    assertFalse(uncaught);
+    return;
+  }
+}
+
+function assertUncaught(f) {
+  try {f()} finally {
+    assertTrue(uncaught);
+    return;
+  }
+}
+
+
+assertUncaught(() => {
+  for (var a of [1, 2, 3]) {
+    throw a
+  }
+});
+
+assertUncaught(() => {
+  for (var a of [1, 2, 3]) {
+    try {throw a} finally {}
+  }
+});
+
+assertCaught(() => {
+  for (var a of [1, 2, 3]) {
+    try {
+      try {throw a} finally {}
+    } catch(_) {}
+  }
+});
+
+assertCaught(() => {
+  try {
+    for (var a of [1, 2, 3]) {
+      try {throw a} finally {}
+    }
+  } catch(_) {}
+});
+
+
+assertFalse(error);