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| author | Andi Kleen <ak@linux.intel.com> | 2012-09-17 14:09:15 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-09-17 15:00:38 -0700 |
| commit | 9a858dc7cebce01a7bb616bebb85087fa2b40871 (patch) | |
| tree | 70e8b7fd41d6503e105cdd0b5b9ed3e6f7c464ee | |
| parent | 579035dc5ddd6d48fd8529e7358b03d911ab9d8a (diff) | |
| download | linux-9a858dc7cebce01a7bb616bebb85087fa2b40871.tar.gz linux-9a858dc7cebce01a7bb616bebb85087fa2b40871.tar.bz2 linux-9a858dc7cebce01a7bb616bebb85087fa2b40871.zip | |
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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/compiler-gcc4.h | 7 | ||||
| -rw-r--r-- | include/linux/compiler.h | 4 |
2 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 2f4079175afb..934bc34d5f99 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -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 diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 923d093c9cea..f430e4162f41 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -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)) |