From bd76bcd52b4cf9a91087324ff9a59675c3570691 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@slava-pestovs-macbook-pro.local>
Date: Mon, 16 Nov 2009 00:52:32 -0600
Subject: [PATCH] vm: fix problem in card marking if first block is free

---
 vm/data_heap.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/vm/data_heap.cpp b/vm/data_heap.cpp
index 43fbd930f1..c9d9ef0854 100755
--- a/vm/data_heap.cpp
+++ b/vm/data_heap.cpp
@@ -166,6 +166,8 @@ the GC. Some types have a binary payload at the end (string, word, DLL) which
 we ignore. */
 cell object::binary_payload_start() const
 {
+	if(free_p()) return 0;
+
 	switch(type())
 	{
 	/* these objects do not refer to other objects at all */