lkml.org 
[lkml]   [2012]   [Jun]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] linux/bug.h: make BUILD_BUG_ON generate compile-time error
This is pretty straight-forward. __compiletime_error is defined in
compiler-gcc4.h with appropriate version checks, so shouldn't break on
older compilers. This makes the difference between getting an error at
link-time and getting one at compile time. Example:

/home/daniel/proj/kernel/grbtest/grbtest2.c:83:2: error: call to
‘__build_bug_on_failed’ declared with attribute error: BUILD_BUG_ON
failed: !__builtin_constant_p(count)

The above points me directly to where I called BUILD_BUG_ON. Note that
I'm moving __build_bug_on_failed out of the global scope, just so it can
be re-declared with different attributes each time.

Daniel
From 3af9a38225e6d074ef6b22e6c99c2503bc581953 Mon Sep 17 00:00:00 2001
From: Daniel Santos <daniel.santos@pobox.com>
Date: Mon, 4 Jun 2012 06:13:41 -0500
Subject: linux/bug.h: make BUILD_BUG_ON generate compile-time error

---
include/linux/bug.h | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/include/linux/bug.h b/include/linux/bug.h
index 72961c3..d35d6e9 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -48,11 +48,12 @@ struct pt_regs;
#ifndef __OPTIMIZE__
#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
#else
-extern int __build_bug_on_failed;
-#define BUILD_BUG_ON(condition) \
- do { \
- ((void)sizeof(char[1 - 2*!!(condition)])); \
- if (condition) __build_bug_on_failed = 1; \
+#define BUILD_BUG_ON(condition) \
+ do { \
+ extern void __build_bug_on_failed(void) \
+ __compiletime_error("BUILD_BUG_ON failed: " #condition);\
+ ((void)sizeof(char[1 - 2*!!(condition)])); \
+ if (condition) __build_bug_on_failed(); \
} while(0)
#endif

--
1.7.3.4
\
 
 \ /
  Last update: 2012-06-04 14:21    [from the cache]
©2003-2011 Jasper Spaans