Use GetCurrentStackPosition() to calculate the stack limit.

src/background-parsing-task.cc

Index: src/background-parsing-task.cc
diff --git a/src/background-parsing-task.cc b/src/background-parsing-task.cc
index fc5cbb45a68197d4e40060afd22d5bf8469fa952..9a914091929145525f8b939c986926ab648ce07a 100644
--- a/src/background-parsing-task.cc
+++ b/src/background-parsing-task.cc
@@ -63,8 +63,7 @@ void BackgroundParsingTask::Run() {
 
   // Reset the stack limit of the parser to reflect correctly that we're on a
   // background thread.
-  uintptr_t stack_limit =
-      reinterpret_cast<uintptr_t>(&stack_limit) - stack_size_ * KB;
+  uintptr_t stack_limit = GetCurrentStackPosition() - stack_size_ * KB;
   source_->parser->set_stack_limit(stack_limit);
 
   // Nullify the Isolate temporarily so that the background parser doesn't