Disallow gcc versions 4.1.{0,1}
authorLinus Torvalds <torvalds@linux-foundation.org>
Fri, 2 Jan 2009 17:29:43 +0000 (09:29 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 2 Jan 2009 17:29:43 +0000 (09:29 -0800)
These compiler versions are known to miscompile __weak functions and
thus generate kernels that don't necessarily work correctly.  If a weak
function is int he same compilation unit as a caller, gcc may end up
inlining it, and thus binding the weak function too early.

See

    http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781

for details.

Cc: Adrian Bunk <bunk@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/compiler-gcc4.h

index aa42621..0999271 100644 (file)
@@ -2,6 +2,11 @@
 #error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
 #endif
 
+/* GCC 4.1.[01] miscompiles __weak */
+#if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
+# error Your version of gcc miscompiles the __weak directive
+#endif
+
 #define __used                 __attribute__((__used__))
 #define __must_check           __attribute__((warn_unused_result))
 #define __compiler_offsetof(a,b) __builtin_offsetof(a,b)