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    SubjectRe: [PATCH] x86-64: Prevent gcc from optimizing away venosys_1()
    On Fri, Jun 03, 2011 at 05:32:06PM -0400, Dave Anderson wrote:
    >
    >
    > ----- Original Message -----
    > > > return 0;
    > > > }
    > > >
    > > > -static long __vsyscall(3) venosys_1(void)
    > > > +long __vsyscall(3) venosys_1(void)
    > >
    > > Better add a __used too. Otherwise it can be optimized out again
    > > in some builds e.g. when someone enables gc-sections for the linker.
    >
    > Considering that all of the vsyscall prototypes have this attribute:
    >
    > #define __vsyscall(nr) \
    > __attribute__ ((unused, __section__(".vsyscall_" #nr))) notrace
    >
    > How would any of them work?

    unused is just to prevent warnings I think. used stops the optimizer
    from throwing it away.

    It would make more sense to drop the unused and add an used. I think
    used prevents the warnings too.

    -Andi

    --
    ak@linux.intel.com -- Speaking for myself only.


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