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Commit 9a858dc7 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

compiler.h: add __visible 



gcc 4.6+ has support for a externally_visible attribute that prevents the
optimizer from optimizing unused symbols away.  Add a __visible macro to
use it with that compiler version or later.

This is used (at least) by the "Link Time Optimization" patchset.

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 579035dc

include/linux/compiler-gcc4.h

+7 −0
Original line number Diff line number Diff line
@@ -49,6 +49,13 @@ 
#endif

#endif



#if __GNUC_MINOR__ >= 6

/*

 * Tell the optimizer that something else uses this function or variable.

 */

#define __visible __attribute__((externally_visible))

#endif



#if __GNUC_MINOR__ > 0

#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)

#endif

include/linux/compiler.h

+4 −0
Original line number Diff line number Diff line
@@ -278,6 +278,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); 
# define __section(S) __attribute__ ((__section__(#S)))

#endif



#ifndef __visible

#define __visible

#endif



/* Are two types/vars the same type (ignoring qualifiers)? */

#ifndef __same_type

# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))