compiler: introduce __used and __maybe_unused
commit0d7ebbbc6eaa5539f78ab20ed6ff1725a4e332ef
authorDavid Rientjes <rientjes@google.com>
Wed, 9 May 2007 09:35:27 +0000 (9 02:35 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 9 May 2007 19:30:56 +0000 (9 12:30 -0700)
treeddef8183ac6440e96678fd4d1159ee86619e2a97
parentf7e4217b007d1f73e7e3cf10ba4fea4a608c603f
compiler: introduce __used and __maybe_unused

__used is defined to be __attribute__((unused)) for all pre-3.3 gcc
compilers to suppress warnings for unused functions because perhaps they
are referenced only in inline assembly.  It is defined to be
__attribute__((used)) for gcc 3.3 and later so that the code is still
emitted for such functions.

__maybe_unused is defined to be __attribute__((unused)) for both function
and variable use if it could possibly be unreferenced due to the evaluation
of preprocessor macros.  Function prototypes shall be marked with
__maybe_unused if the actual definition of the function is dependant on
preprocessor macros.

No update to compiler-intel.h is necessary because ICC supports both
__attribute__((used)) and __attribute__((unused)) as specified by the gcc
manual.

__attribute_used__ is deprecated and will be removed once all current
code is converted to using __used.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/compiler-gcc.h
include/linux/compiler-gcc3.h
include/linux/compiler-gcc4.h
include/linux/compiler.h