Experimental code to detect transitive closure of parser code which causes new-space allocations

runtime/vm/thread.h

Index: runtime/vm/thread.h
diff --git a/runtime/vm/thread.h b/runtime/vm/thread.h
index 3a226e4ee583bb912841e21e1ba6d3006e33a63c..12e9b46e9e7441916d2f6505afb912cae6c3d602 100644
--- a/runtime/vm/thread.h
+++ b/runtime/vm/thread.h
@@ -300,6 +300,7 @@ class Thread : public BaseThread {
   Isolate* isolate() const { return isolate_; }
   static intptr_t isolate_offset() { return OFFSET_OF(Thread, isolate_); }
   bool IsMutatorThread() const;
+  bool IsInsideParser() const { return inside_parser_; }
   bool CanCollectGarbage() const;
 
   // Offset of Dart TimelineStream object.
@@ -695,6 +696,9 @@ class Thread : public BaseThread {
   uword stack_limit_;
   uword stack_overflow_flags_;
   Isolate* isolate_;
+  bool inside_parser_;
+  friend class EnterParserScope;
+  friend class LeaveParserScope;
   Heap* heap_;
   uword top_exit_frame_info_;
   StoreBufferBlock* store_buffer_block_;