Move FormatStackTrace to C++

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 16696e2c98a1c49bde521d55c068a57a96ba9428..8467989e31ee963062a5b0ac5c3829d8e8e65612 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -432,6 +432,17 @@ class StackTraceHelper {
   bool encountered_strict_function_;
 };
 
+namespace {
+
+// TODO(jgruber): Fix all cases in which frames give us a hole value (e.g. the
+// receiver in RegExp constructor frames.
+Handle<Object> HoleToUndefined(Isolate* isolate, Handle<Object> in) {

[Yang, 2016/08/01 06:49:18]

Let's call this TheHoleToUndefined.

[jgruber, 2016/08/01 10:52:55]

Done.

+  return (in->IsTheHole(isolate))
+             ? Handle<Object>::cast(isolate->factory()->undefined_value())
+             : in;
+}
+}
+
 Handle<Object> Isolate::CaptureSimpleStackTrace(Handle<JSReceiver> error_object,
                                                 FrameSkipMode mode,
                                                 Handle<Object> caller) {
@@ -491,7 +502,7 @@ Handle<Object> Isolate::CaptureSimpleStackTrace(Handle<JSReceiver> error_object,
           Handle<Smi> offset(Smi::FromInt(frames[i].code_offset()), this);
 
           elements = MaybeGrow(this, elements, cursor, cursor + 4);
-          elements->set(cursor++, *recv);
+          elements->set(cursor++, *HoleToUndefined(this, recv));
           elements->set(cursor++, *fun);
           elements->set(cursor++, *abstract_code);
           elements->set(cursor++, *offset);