Parser recursion check

runtime/vm/parser.h

Index: runtime/vm/parser.h
diff --git a/runtime/vm/parser.h b/runtime/vm/parser.h
index edc8fdfd01d88936f8e608bcffc5d97cf73729b1..9d9e50346ca2b5fac395f6ff8635c8f659cdc5fb 100644
--- a/runtime/vm/parser.h
+++ b/runtime/vm/parser.h
@@ -36,6 +36,7 @@ struct MemberDesc;
 struct ParamList;
 struct QualIdent;
 class TopLevel;
+class RecursionChecker;
 
 // The class ParsedFunction holds the result of parsing a function.
 class ParsedFunction : public ZoneAllocated {
@@ -365,6 +366,9 @@ class Parser : public ValueObject {
                                          const Function& constructor,
                                          const TypeArguments& type_arguments);
 
+  // Report error if parsed code is too deeply nested; avoid stack overflow.
+  void CheckStack();
+
   // Report already formatted error.
   static void ReportError(const Error& error);
 
@@ -894,6 +898,9 @@ class Parser : public ValueObject {
   // Indentation of parser trace.
   intptr_t trace_indent_;
 
+  intptr_t recursion_counter_;
+  friend class RecursionChecker;
+
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };