v8: port fbff705 from v0.10 to v0.12

fbff705
Add v8::Isolate::SetAbortOnUncaughtException() so the user can be
notified when an uncaught exception has bubbled.

Fixes: nodejs/node-v0.x-archive#8877
PR-URL: nodejs/node-v0.x-archive#25835
Reviewed-By: misterdjules - Julien Gilli <jgilli@nodejs.org>

deps/v8/include/v8.h

@@ -4186,6 +4186,17 @@ class V8_EXPORT Isolate {
    */
   static Isolate* GetCurrent();
 
+  /**
+   * Custom callback used by embedders to help V8 determine if it should abort
+   * when it throws and no internal handler can catch the exception.
+   * If FLAG_abort_on_uncaught_exception is true, then V8 will abort if either:
+   * - no custom callback is set.
+   * - the custom callback set returns true.
+   * Otherwise it won't abort.
+   */
+  typedef bool (*abort_on_uncaught_exception_t)(Isolate*);
+  void SetAbortOnUncaughtException(abort_on_uncaught_exception_t callback);
+
   /**
    * Methods below this point require holding a lock (using Locker) in
    * a multi-threaded environment.

deps/v8/src/api.cc

@@ -6556,6 +6556,13 @@ void Isolate::Enter() {
 }
 
 
+void Isolate::SetAbortOnUncaughtException(
+      abort_on_uncaught_exception_t callback) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
+  isolate->SetAbortOnUncaughtException(callback);
+}
+
+
 void Isolate::Exit() {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->Exit();

deps/v8/src/isolate.cc

@@ -1090,19 +1090,30 @@ void Isolate::DoThrow(Object* exception, MessageLocation* location) {
         thread_local_top()->pending_message_end_pos_ = location->end_pos();
       }
 
-      // If the abort-on-uncaught-exception flag is specified, abort on any
-      // exception not caught by JavaScript, even when an external handler is
-      // present.  This flag is intended for use by JavaScript developers, so
-      // print a user-friendly stack trace (not an internal one).
+      // If the abort-on-uncaught-exception flag is specified, and if the
+      // exception is not caught by JavaScript (even when an external handler is
+      // present).
       if (fatal_exception_depth == 0 &&
           FLAG_abort_on_uncaught_exception &&
           (report_exception || can_be_caught_externally)) {
-        fatal_exception_depth++;
-        PrintF(stderr,
-               "%s\n\nFROM\n",
-               MessageHandler::GetLocalizedMessage(this, message_obj).get());
-        PrintCurrentStackTrace(stderr);
-        base::OS::Abort();
+        // If the embedder didn't specify a custom uncaught exception callback,
+        // or if the custom callback determined that V8 should abort, then
+        // abort
+        bool should_abort = !abort_on_uncaught_exception_callback_ ||
+                             abort_on_uncaught_exception_callback_(
+                                 reinterpret_cast<v8::Isolate*>(this)
+                             );
+
+        if (should_abort) {
+          fatal_exception_depth++;
+          // This flag is intended for use by JavaScript developers, so
+          // print a user-friendly stack trace (not an internal one).
+          PrintF(stderr,
+                 "%s\n\nFROM\n",
+                 MessageHandler::GetLocalizedMessage(this, message_obj).get());
+          PrintCurrentStackTrace(stderr);
+          base::OS::Abort();
+        }
       }
     } else if (location != NULL && !location->script().is_null()) {
       // We are bootstrapping and caught an error where the location is set
@@ -1299,6 +1310,12 @@ void Isolate::SetCaptureStackTraceForUncaughtExceptions(
 }
 
 
+void Isolate::SetAbortOnUncaughtException(
+      v8::Isolate::abort_on_uncaught_exception_t callback) {
+  abort_on_uncaught_exception_callback_ = callback;
+}
+
+
 Handle<Context> Isolate::native_context() {
   return handle(context()->native_context());
 }
@@ -1474,7 +1491,8 @@ Isolate::Isolate()
       num_sweeper_threads_(0),
       stress_deopt_count_(0),
       next_optimization_id_(0),
-      use_counter_callback_(NULL) {
+      use_counter_callback_(NULL),
+      abort_on_uncaught_exception_callback_(NULL) {
   id_ = base::NoBarrier_AtomicIncrement(&isolate_counter_, 1);
   TRACE_ISOLATE(constructor);
 

deps/v8/src/isolate.h

@@ -707,6 +707,9 @@ class Isolate {
       int frame_limit,
       StackTrace::StackTraceOptions options);
 
+  typedef bool (*abort_on_uncaught_exception_t)(v8::Isolate*);
+  void SetAbortOnUncaughtException(abort_on_uncaught_exception_t callback);
+
   void PrintCurrentStackTrace(FILE* out);
   void PrintStack(StringStream* accumulator);
   void PrintStack(FILE* out);
@@ -1331,6 +1334,8 @@ class Isolate {
 
   v8::Isolate::UseCounterCallback use_counter_callback_;
 
+  abort_on_uncaught_exception_t abort_on_uncaught_exception_callback_;
+
   friend class ExecutionAccess;
   friend class HandleScopeImplementer;
   friend class IsolateInitializer;