On Fri, Mar 18, 2016 at 01:17:54PM -0700, Nithin Raju wrote:
> The previous definitions of these variables using designated
> initializers caused a variety of issues when attempting to
> compile with MSVC, particularly if including these headers from C++
> code. By defining them like this, we can appease MSVC and keep the
> definitions the same on all platforms.
>
> Suggested-by: Yin Lin <li...@vmware.com>
> Signed-off-by: Nithin Raju <nit...@vmware.com>
> ---
> lib/list.h | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/lib/list.h b/lib/list.h
> index f9c9d85..24c57ba 100644
> --- a/lib/list.h
> +++ b/lib/list.h
> @@ -24,10 +24,14 @@
> #include "openvswitch/list.h"
>
> /* "struct ovs_list" with pointers that will (probably) cause segfaults if
> - * dereferenced and, better yet, show up clearly in a debugger. */
> -#define OVS_LIST_POISON \
> -(struct ovs_list) { (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL, \
> - (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL }
> + * dereferenced and, better yet, show up clearly in a debugger.
> +
> + * MSVC2015 doesn't support designated initializers when compiling C++,
> + * and doesn't support ternary operators with non-designated initializers.
> + * So we use these static definitions rather than using initializer macros.
> */
> +static const struct ovs_list OVS_LIST_POISON =
> + { (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL,
> + (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL };
This causes a lot of new warnings from sparse, e.g.:
../lib/list.h:33:39: warning: cast truncates bits from constant value
(cccccccccccccccc becomes cccccccc)
../lib/list.h:34:39: warning: cast truncates bits from constant value
(cccccccccccccccc becomes cccccccc)
How about the following? It reuses a trick we previously have used in
rculist.h.
--8<--------------------------cut here-------------------------->8--
From: Nithin Raju <nit...@vmware.com>
Date: Fri, 18 Mar 2016 13:17:54 -0700
Subject: [PATCH] list.h: Define OVS_LIST_POISON statically
The previous definitions of these variables using designated
initializers caused a variety of issues when attempting to
compile with MSVC, particularly if including these headers from C++
code. By defining them like this, we can appease MSVC and keep the
definitions the same on all platforms.
Suggested-by: Yin Lin <li...@vmware.com>
Signed-off-by: Nithin Raju <nit...@vmware.com>
Signed-off-by: Ben Pfaff <b...@ovn.org>
---
lib/list.h | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/lib/list.h b/lib/list.h
index f9c9d85..96bbafd 100644
--- a/lib/list.h
+++ b/lib/list.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -24,10 +24,14 @@
#include "openvswitch/list.h"
/* "struct ovs_list" with pointers that will (probably) cause segfaults if
- * dereferenced and, better yet, show up clearly in a debugger. */
-#define OVS_LIST_POISON \
-(struct ovs_list) { (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL, \
- (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL }
+ * dereferenced and, better yet, show up clearly in a debugger.
+
+ * MSVC2015 doesn't support designated initializers when compiling C++,
+ * and doesn't support ternary operators with non-designated initializers.
+ * So we use these static definitions rather than using initializer macros. */
+static const struct ovs_list OVS_LIST_POISON =
+ { (struct ovs_list *) (UINTPTR_MAX / 0xf * 0xc),
+ (struct ovs_list *) (UINTPTR_MAX / 0xf * 0xc) };
static inline void list_init(struct ovs_list *);
static inline void list_poison(struct ovs_list *);
--
2.1.3
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