Re: [PATCH] more out of bounds checking improvements

[Florian Weimer via Libc-alpha <libc-alpha@sourceware.org>]

* Andreas Schwab:

> On Mai 10 2021, Martin Sebor via Libc-alpha wrote:
>
>> It doesn't need to be disabled for GCC 11 but I don't know how to
>> be this selective with these version macros.  If it's okay to use
>> __GNUC__ then this works:
>>
>> index 9389f6b548..6a061e6457 100644
>> --- a/nss/makedb.c
>> +++ b/nss/makedb.c
>> @@ -792,7 +792,15 @@ write_output (int fd)
>>                           + nhashentries_total * sizeof (stridx_t)));
>>    header->allocate = file_offset;
>>
>> -  /* Help GCC 10 see iov_nelts doesn't overflow the writev argument.  */
>> +  assert (iov_nelts <= INT_MAX);
>> +
>> +#if __GNUC__ == 10
>
> You can use __GNUC_PREREQ (10, 0) && !__GNUC_PREREQ (11, 0)

That works for me too.

I've tested the previous version (partially quoted above) with GCC 11
and GCC 10, and it builds.

It's too late for me to test Andreas' proposal today, but I think it
should be safe to push it.  I can retest it tomorrow with GCC 9/10/11,
just to be sure.

Thanks,
Florian