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From: Josh Triplett <josh@joshtriplett.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 5/5] bug: Make BUG() call unreachable()
Date: Tue, 25 Feb 2014 19:49:36 -0800	[thread overview]
Message-ID: <d97712e037ea4c90e9cb30c56229383d257831de.1393385236.git.josh@joshtriplett.org> (raw)
In-Reply-To: <469b5dc113cb468232291527642f8dc47663e945.1393385236.git.josh@joshtriplett.org>

This effectively causes BUG() to act like a function with the noreturn
attribute, which prevents GCC from warning about the code that follows
BUG() (for instance, warning about not returning a value in a non-void
function after calling BUG()).

This actually makes the kernel smaller; bloat-o-meter summary:
add/remove: 2/7 grow/shrink: 34/57 up/down: 475/-1233 (-758)

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
---
 include/asm-generic/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 653c44a..5f69248 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -134,7 +134,7 @@ extern void warn_slowpath_null(const char *file, const int line);
 
 #else /* !CONFIG_BUG */
 #ifndef HAVE_ARCH_BUG
-#define BUG() do {} while (0)
+#define BUG() do { unreachable(); } while (0)
 #endif
 
 #ifndef HAVE_ARCH_WARN_ON
-- 
1.9.0

  parent reply	other threads:[~2014-02-26  3:49 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-26  3:48 [PATCH v2 1/5] bug: When !CONFIG_BUG, simplify WARN_ON_ONCE and family Josh Triplett
2014-02-26  3:48 ` Josh Triplett
2014-02-26  3:48 ` [PATCH v2 2/5] include/asm-generic/bug.h: Style fix: s/while(0)/while (0)/ Josh Triplett
2014-02-26  3:48   ` Josh Triplett
2014-02-26 13:25   ` Arnd Bergmann
2014-02-26 13:25     ` Arnd Bergmann
2014-02-26  3:49 ` [PATCH v2 3/5] bug: When !CONFIG_BUG, make WARN call no_printk to check format and args Josh Triplett
2014-02-26  3:49   ` Josh Triplett
2014-02-26 13:25   ` Arnd Bergmann
2014-02-26 13:25     ` Arnd Bergmann
2014-02-26  3:49 ` [PATCH v2 4/5] bug: Use a common definition of BUG_ON regardless of CONFIG_BUG Josh Triplett
2014-02-26  3:49   ` Josh Triplett
2014-02-26 13:26   ` Arnd Bergmann
2014-02-26  3:49 ` Josh Triplett [this message]
2014-02-26  3:49   ` [PATCH v2 5/5] bug: Make BUG() call unreachable() Josh Triplett
2014-02-26 13:29   ` Arnd Bergmann
2014-02-26 13:29     ` Arnd Bergmann
2014-02-26 14:58     ` Josh Triplett
2014-02-26 14:58       ` Josh Triplett
2014-02-27 19:19       ` Arnd Bergmann
2014-02-28  0:16         ` Josh Triplett
2014-02-28  8:55           ` Arnd Bergmann
2014-03-10  1:00             ` [PATCH v3 1/5] bug: When !CONFIG_BUG, simplify WARN_ON_ONCE and family Josh Triplett
2014-03-10  1:01               ` [PATCH v3 2/5] include/asm-generic/bug.h: Style fix: s/while(0)/while (0)/ Josh Triplett
2014-03-10  1:02               ` [PATCH v3 3/5] bug: When !CONFIG_BUG, make WARN call no_printk to check format and args Josh Triplett
2014-03-10  1:02                 ` Josh Triplett
2014-03-10  1:02               ` [PATCH v3 4/5] bug: Make BUG() always stop the machine Josh Triplett
2014-03-10  1:03               ` [PATCH v3 5/5] x86: Always define BUG() and HAVE_ARCH_BUG, even with !CONFIG_BUG Josh Triplett
2014-03-11 16:40               ` [PATCH v3 1/5] bug: When !CONFIG_BUG, simplify WARN_ON_ONCE and family Arnd Bergmann
2014-03-11 17:49                 ` Josh Triplett
2014-03-11 17:49                   ` Josh Triplett
2014-02-26 13:24 ` [PATCH v2 " Arnd Bergmann

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