Version 3.28.71.2 (merged r23115)

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 538071af1924a2dd24b627a6bcfb813a9bcfc2fc..abe50f69bca84e446d061f0e79daac199250c7f9 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -5545,6 +5545,11 @@ bool v8::String::CanMakeExternal() {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
 
+  // TODO(yangguo): Externalizing sliced/cons strings allocates.
+  // This rule can be removed when all code that can
+  // trigger an access check is handlified and therefore GC safe.
+  if (isolate->heap()->old_pointer_space()->Contains(*obj)) return false;
+
   if (isolate->string_tracker()->IsFreshUnusedString(obj)) return false;
   int size = obj->Size();  // Byte size of the original string.
   if (size < i::ExternalString::kShortSize) return false;