Use a different map to distinguish eval contexts

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index cdbc6fe04dbf8f4fcbe5cee231017e8c56245046..8706750f55ffa2b29e35fa062d15df665136962d 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -838,6 +838,21 @@ Handle<Context> Factory::NewModuleContext(Handle<Module> module,
   return context;
 }
 
+Handle<Context> Factory::NewEvalContext(Handle<Module> module,
+                                        Handle<JSFunction> function,
+                                        Handle<ScopeInfo> scope_info) {
+  DCHECK_EQ(scope_info->scope_type(), EVAL_SCOPE);
+  Handle<FixedArray> array =
+      NewFixedArray(scope_info->ContextLength(), TENURED);
+  array->set_map_no_write_barrier(*module_context_map());
+  Handle<Context> context = Handle<Context>::cast(array);
+  context->set_closure(*function);
+  context->set_previous(function->context());
+  context->set_extension(*module);
+  context->set_native_context(function->native_context());
+  DCHECK(context->IsModuleContext());
+  return context;
+}
 
 Handle<Context> Factory::NewFunctionContext(int length,
                                             Handle<JSFunction> function) {