diff options
Diffstat (limited to 'include/linux/compiler-gcc4.h')
-rwxr-xr-x | include/linux/compiler-gcc4.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h new file mode 100755 index 0000000..94dea3f --- /dev/null +++ b/include/linux/compiler-gcc4.h @@ -0,0 +1,61 @@ +#ifndef __LINUX_COMPILER_H +#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead." +#endif + +/* GCC 4.1.[01] miscompiles __weak */ +#ifdef __KERNEL__ +# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1 +# error Your version of gcc miscompiles the __weak directive +# endif +#endif + +#define __used __attribute__((__used__)) +#define __must_check __attribute__((warn_unused_result)) +#define __compiler_offsetof(a,b) __builtin_offsetof(a,b) +#define __always_inline inline __attribute__((always_inline)) + +/* + * A trick to suppress uninitialized variable warning without generating any + * code + */ +#define uninitialized_var(x) x = x + +#if __GNUC_MINOR__ >= 3 +/* Mark functions as cold. gcc will assume any path leading to a call + to them will be unlikely. This means a lot of manual unlikely()s + are unnecessary now for any paths leading to the usual suspects + like BUG(), printk(), panic() etc. [but let's keep them for now for + older compilers] + + Early snapshots of gcc 4.3 don't support this and we can't detect this + in the preprocessor, but we can live with this because they're unreleased. + Maketime probing would be overkill here. + + gcc also has a __attribute__((__hot__)) to move hot functions into + a special section, but I don't see any sense in this right now in + the kernel context */ +#define __cold __attribute__((__cold__)) + + +#if __GNUC_MINOR__ >= 5 +/* + * Mark a position in code as unreachable. This can be used to + * suppress control flow warnings after asm blocks that transfer + * control elsewhere. + * + * Early snapshots of gcc 4.5 don't support this and we can't detect + * this in the preprocessor, but we can live with this because they're + * unreleased. Really, we need to have autoconf for the kernel. + */ +#define unreachable() __builtin_unreachable() +#endif + +#endif + +#if __GNUC_MINOR__ > 0 +#define __compiletime_object_size(obj) __builtin_object_size(obj, 0) +#endif +#if __GNUC_MINOR__ >= 4 +#define __compiletime_warning(message) __attribute__((warning(message))) +#define __compiletime_error(message) __attribute__((error(message))) +#endif |