1 files changed, 3 insertions, 1 deletions
diff --git a/parser.h b/parser.h
index c5a59abc5d..3c7bb4e97d 100644
--- a/parser.h
+++ b/parser.h
@@ -44,7 +44,9 @@ typedef struct yy_parser {
 
     int		    yylen;	/* length of active reduction */
     yy_stack_frame  *stack;	/* base of stack */
-    yy_stack_frame  *stack_max1;/* (top-1)th element of alloacted stack */
+    yy_stack_frame  *stack_maxbase;/* (stack + alloced size - YY_MAXRULE)
+                                    * it's offset by -YY_MAXRULE to make
+                                    * overflow checks quicker */
     yy_stack_frame  *ps;	/* current stack frame */
 
     /* lexer state */