From 9a858dc7cebce01a7bb616bebb85087fa2b40871 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Mon, 17 Sep 2012 14:09:15 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compiler-gcc4.h | 7 +++++++ include/linux/compiler.h | 4 ++++ 2 files changed, 11 insertions(+) (limited to 'include') diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 2f40791..934bc34 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 923d093..f430e41 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)) -- cgit v1.1