From: Rob Pike <r@golang.org>
Date: Thu, 30 Jan 2014 00:14:45 +0000 (-0800)
Subject: cmd/8g: don't crash if Prog->u.branch is nil
X-Git-Tag: go1.3beta1~845
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=289d46399b794a15be12f57a8162fa514bd8f306;p=gostls13.git

cmd/8g: don't crash if Prog->u.branch is nil
The code is copied from cmd/6g.
Empirically, all branch targets are nil in this code so
something is still wrong, but at least this stops 8g -S
from crashing.

Update #7178

LGTM=dave, iant
R=iant, dave
CC=golang-codereviews
https://golang.org/cl/58400043
---

diff --git a/src/cmd/8g/list.c b/src/cmd/8g/list.c
index 96954d4bb3..558d9c690d 100644
--- a/src/cmd/8g/list.c
+++ b/src/cmd/8g/list.c
@@ -107,7 +107,10 @@ Dconv(Fmt *fp)
 		break;
 
 	case D_BRANCH:
-		snprint(str, sizeof(str), "%d", a->u.branch->loc);
+		if(a->u.branch == nil)
+			snprint(str, sizeof(str), "<nil>");
+		else
+			snprint(str, sizeof(str), "%d", a->u.branch->loc);
 		break;
 
 	case D_EXTERN: