From: Austin Clements <austin@google.com>
Date: Wed, 22 Oct 2014 20:39:31 +0000 (-0400)
Subject: [dev.power64] runtime: fix early GC of Defer objects
X-Git-Tag: go1.5beta1~2684^2~25^2~14
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=a9b9ecc9ef3a73ac0ab74b57ca7ef864f1bd9ac8;p=gostls13.git

[dev.power64] runtime: fix early GC of Defer objects

go_bootstrap was panicking during runtime initialization
(under runtime.main) because Defer objects were being
prematurely GC'd.  This happened because of an incorrect
change to runtime·unrollgcprog_m to make it endian-agnostic
during the conversion of runtime bitmaps to byte arrays.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/161960044
---

diff --git a/src/runtime/mgc0.c b/src/runtime/mgc0.c
index d376c1cf69..02f7eba120 100644
--- a/src/runtime/mgc0.c
+++ b/src/runtime/mgc0.c
@@ -1799,7 +1799,7 @@ runtime·unrollgcprog_m(void)
 		}
 		
 		// atomic way to say mask[0] = 1
-		x = typ->gc[0];
+		x = *(uintptr*)mask;
 		((byte*)&x)[0] = 1;
 		runtime·atomicstorep((void**)mask, (void*)x);
 	}