Fix braindead Handle::is_identical_to

src/handles-inl.h

Index: src/handles-inl.h
diff --git a/src/handles-inl.h b/src/handles-inl.h
index 5a3e9ed2744ac9c0a0ef1c319648d23e174508f1..2747cbcc1d0f2ed25eafbb11a51e23c355dea150 100644
--- a/src/handles-inl.h
+++ b/src/handles-inl.h
@@ -55,6 +55,8 @@ template <typename T>
 inline bool Handle<T>::is_identical_to(const Handle<T> other) const {
   ASSERT(location_ == NULL ||
          reinterpret_cast<Address>(*location_) != kZapValue);

[Michael Starzinger, 2013/05/07 11:58:37]

As discussed offline: This should actually check against kHandleZapValue here.
Let's change it to catch all failures (i.e. with IsFailure).

[rossberg, 2013/05/07 12:00:25]

Done (here and elsewhere).

+  if (location_ == other.location_) return true;
+  if (location_ == NULL || other.location_ == NULL) return false;
   // Dereferencing deferred handles to check object equality is safe.
   SLOW_ASSERT(IsDereferenceAllowed(true) && other.IsDereferenceAllowed(true));
   return *location_ == *other.location_;
@@ -73,14 +75,14 @@ template <typename T>
 inline T** Handle<T>::location() const {
   ASSERT(location_ == NULL ||
          reinterpret_cast<Address>(*location_) != kZapValue);
-  SLOW_ASSERT(IsDereferenceAllowed(false));
+  SLOW_ASSERT(location_ == NULL || IsDereferenceAllowed(false));
   return location_;
 }
 
 #ifdef DEBUG
 template <typename T>
 bool Handle<T>::IsDereferenceAllowed(bool allow_deferred) const {
-  if (location_ == NULL) return true;
+  ASSERT(location_ != NULL);
   Object* object = *BitCast<T**>(location_);
   if (object->IsSmi()) return true;
   HeapObject* heap_object = HeapObject::cast(object);