gold patch committed: Provide own version of ffsll
Ian Lance Taylor
Mon Mar 30 23:17:00 GMT 2009
Dave Korn <firstname.lastname@example.org> writes:
> Ian Lance Taylor wrote:
>> gold uses ffsll, particularly since gcc expands it inline when
>> possible. However, some systems don't have ffsll. I committed this
>> patch to add a version when the system does not have it. I also tweaked
>> the other replacement functions, adding declarations so that they would
>> build without warnings.
> Did you consider adding these to libiberty instead? I don't know if they're
> all appropriate but some of them might well make handy additions, mightn't
I thought about it. I added memmem to libiberty. The version of mremap
in gold isn't general; it only does what gold needs. ffsll is kind of
special purpose and I'm not convinced anything else will call it.
> +ffsll (long long arg)
> + unsigned long long i;
> + int ret;
> + ret = 0;
> + for (i = (unsigned long long) arg; i != 0; i >>= 1)
> + ++ret;
> + return ret;
> ... does that really find the first set bit? It looks to me like it counts
> all the one bits. Possibly the terminating condition was meant to test "(i &
> 1) != 0"?
It doesn't matter too much, since gold will only call it with a power of
2. But, yeah, I suppose it ought to work properly. I committed the
appended patch. Thanks.
2009-03-30 Ian Lance Taylor <email@example.com>
* ffsll.c (ffsll): Correct implementation.
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