lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 30 Sep 2012 18:29:01 -0500 From: Daniel Santos <danielfsantos@....net> To: Josh Triplett <josh@...htriplett.org> CC: Daniel Santos <daniel.santos@...ox.com>, LKML <linux-kernel@...r.kernel.org>, Andi Kleen <ak@...ux.intel.com>, Andrea Arcangeli <aarcange@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, Christopher Li <sparse@...isli.org>, David Daney <david.daney@...ium.com>, David Howells <dhowells@...hat.com>, Joe Perches <joe@...ches.com>, Konstantin Khlebnikov <khlebnikov@...nvz.org>, linux-sparse@...r.kernel.org, Michel Lespinasse <walken@...gle.com>, Paul Gortmaker <paul.gortmaker@...driver.com>, Pavel Pisa <pisa@....felk.cvut.cz>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Steven Rostedt <rostedt@...dmis.org> Subject: Re: [PATCH 8/10] bug.h: Make BUILD_BUG_ON generate compile-time error On 09/28/2012 09:55 PM, Josh Triplett wrote: > Assuming you don't call BUILD_BUG_ON_MSG more than once per line: > > /tmp$ cat test.c > #define BUILD_BUG_ON_MSG_INTERNAL2(cond, msg, line) \ > do { \ > extern void __build_bug_on_failed_ ## line (void) __attribute__((error(msg))); \ > if (cond) \ > __build_bug_on_failed_ ## line(); \ > } while (0) > > #define BUILD_BUG_ON_MSG_INTERNAL(cond, msg, line) BUILD_BUG_ON_MSG_INTERNAL2(cond, msg, line) > #define BUILD_BUG_ON_MSG(cond, msg) BUILD_BUG_ON_MSG_INTERNAL(cond, msg, __LINE__) > > void f(void) > { > BUILD_BUG_ON_MSG(0, "test 1"); > BUILD_BUG_ON_MSG(1, "test 2"); > BUILD_BUG_ON_MSG(0, "test 3"); > BUILD_BUG_ON_MSG(1, "test 4"); > } > /tmp$ gcc -c test.c > test.c: In function ‘f’: > test.c:14:119: error: call to ‘__build_bug_on_failed_14’ declared with attribute error: test 2 > test.c:16:119: error: call to ‘__build_bug_on_failed_16’ declared with attribute error: test 4 Thanks! This is very nice! I've done a little more research and discovered that there's also a __COUNTER__ macro that is available in gcc 4.3+. Before I realized that it was only available in gcc 4.3, I wrote this little macro: #define _CONCAT1(a, b) a##b #define CONCAT(a, b) _CONCAT1(a, b) #ifdef __COUNTER__ # define UNIQUIFY(prefix) CONCAT(prefix, __COUNTER__) #else # define UNIQUIFY(prefix) CONCAT(prefix, __LINE__) #endif However, this could lead to code might compile on gcc 4.3+, but not compile prior, so this is bad, right? Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists