From: NeilBrown <neil@brown.name>
Date: Wed, 10 Mar 2021 00:58:08 +0000 (+1100)
Subject: parsergen: guard against tos going negative.
X-Git-Url: https://ocean-lang.org/code/?p=ocean;a=commitdiff_plain;h=a6a01462706cb96aaea89188bc66ea34a7899385

parsergen: guard against tos going negative.

Don't continue the parse loop if tos hits zero.

Signed-off-by: NeilBrown <neil@brown.name>
---

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index da9335e..a913cb9 100644
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -2990,7 +2990,7 @@ checks if a given token is in any of these look-ahead sets.
 		void *ret = NULL;
 
 		shift(&p, TK_eof, 0, 1, NULL, states);
-		while (!accepted) {
+		while (!accepted && p.tos > 0) {
 			struct token *err_tk;
 			struct frame *tos = &p.stack[p.tos-1];
 			if (!tk)