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Re: [PATCH] Remove unnecessary IFUNC dispatch for __memset_chk.

On Mon, Aug 10, 2015 at 5:12 PM, OndÅej BÃlka <> wrote:
> On Sun, Aug 09, 2015 at 11:09:20PM -0400, Mike Frysinger wrote:
>> On 09 Aug 2015 14:24, Zack Weinberg wrote:
>> > Is an IFUNC's variant-selecting function called only once per process,
>> > or every time?
>> it's once-per-process.  if it were every time, it'd defeat the point of the
>> optimization.
> No, its once per each shared library.

I don't see how that can possibly be right.  Doesn't each shared
library provide the one true PLT entry for each function it exports?
If not, how can we be obeying the C standard's rules about function
pointer equality?

> thats completely flawed analysis

I would like to believe you about this, because I would have liked not
to have to patch 66 files for explicit_bzero, but I don't; not because
I disbelieve any of your concrete claims - they all sound *plausible*
- but because your attitude does not admit the possibility that you
might be wrong.  Every time there's a question of string function
performance, lately, you insist that your analysis of the situation is
right and everyone else's is wrong, and if challenged you insist that
the other person's analysis and/or benchmarks are invalid.  This is
self-defeating -- the more you do it, the less anyone will listen to
you, even if in some situation you do happen to be right.


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