mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-27 14:43:58 +08:00
1399ff86f2
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 <david.daney@cavium.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: DM <dm.n9107@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
59 lines
2.1 KiB
C
59 lines
2.1 KiB
C
#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)
|
|
|
|
#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__))
|
|
|
|
#define __linktime_error(message) __attribute__((__error__(message)))
|
|
|
|
#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()
|
|
|
|
/* Mark a function definition as prohibited from being cloned. */
|
|
#define __noclone __attribute__((__noclone__))
|
|
|
|
#endif
|
|
#endif
|
|
|
|
#if __GNUC_MINOR__ > 0
|
|
#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
|
|
#endif
|
|
#if __GNUC_MINOR__ >= 4 && !defined(__CHECKER__)
|
|
#define __compiletime_warning(message) __attribute__((warning(message)))
|
|
#define __compiletime_error(message) __attribute__((error(message)))
|
|
#endif
|