From: David Daney Date: Tue, 10 Jan 2012 23:07:25 +0000 (-0800) Subject: kernel.h: add BUILD_BUG() macro X-Git-Tag: v3.3-rc1~113^2~109 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1399ff86f2a2bbacbbe68fa00c5f8c752b344723;p=pandora-kernel.git kernel.h: add BUILD_BUG() macro We can place this in definitions that we expect the compiler to remove by dead code elimination. If this assertion fails, we get a nice error message at build time. The GCC function attribute error("message") was added in version 4.3, so we define a new macro __linktime_error(message) to expand to this for GCC-4.3 and later. This will give us an error diagnostic from the compiler on the line that fails. For other compilers __linktime_error(message) expands to nothing, and we have to be content with a link time error, but at least we will still get a build error. BUILD_BUG() expands to the undefined function __build_bug_failed() and will fail at link time if the compiler ever emits code for it. On GCC-4.3 and later, attribute((error())) is used so that the failure will be noted at compile time instead. Signed-off-by: David Daney Acked-by: David Rientjes Cc: DM Cc: Ralf Baechle Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed