From 5893bd750135a95222ae34f004da7c9bc27af31b Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Mon, 2 Mar 2020 13:32:58 +0900
Subject: [PATCH] [qfcc] Catch erroneous negative builtin numbers

Setting a builtin number negative makes it a non-builtin function, but
possibly in the middle of another function. Not good.
---
 tools/qfcc/source/function.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/qfcc/source/function.c b/tools/qfcc/source/function.c
index 3b844b5a3..e2b87d04a 100644
--- a/tools/qfcc/source/function.c
+++ b/tools/qfcc/source/function.c
@@ -656,6 +656,10 @@ build_builtin_function (symbol_t *sym, expr_t *bi_val, int far)
 		bi = expr_integer (bi_val);
 	else
 		bi = expr_float (bi_val);
+	if (bi < 0) {
+		error (bi_val, "builtin functions must be positive or 0");
+		return 0;
+	}
 	sym->s.func->builtin = bi;
 	reloc_def_func (sym->s.func, sym->s.func->def);
 	build_function (sym);