From a885f84cad0e8a8ee6a20126a2fe28f82e561023 Mon Sep 17 00:00:00 2001
From: Evgeniy Stratonikov <evgeniy@nspcc.ru>
Date: Mon, 25 Oct 2021 10:51:50 +0300
Subject: [PATCH] compiler: fail if some functions are missing

Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>
---
 pkg/compiler/codegen.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go
index 1fefc5e51..4eebd5c9d 100644
--- a/pkg/compiler/codegen.go
+++ b/pkg/compiler/codegen.go
@@ -2168,6 +2168,9 @@ func (c *codegen) replaceLabelWithOffset(ip int, arg []byte) (int, error) {
 	if int(index) > len(c.l) {
 		return 0, fmt.Errorf("unexpected label number: %d (max %d)", index, len(c.l))
 	}
+	if c.l[index] < 0 {
+		return 0, fmt.Errorf("invalid label target: %d at %d", c.l[index], ip)
+	}
 	offset := c.l[index] - ip
 	if offset > math.MaxInt32 || offset < math.MinInt32 {
 		return 0, fmt.Errorf("label offset is too big at the instruction %d: %d (max %d, min %d)",