[Libguestfs] [nbdkit] [filter/nozero] large binary size with GCC 9

[Eric Blake]

On 7/5/19 8:21 AM, Thomas Weißschuh wrote:
> On Fri, 2019-07-05T08:04-0500, Eric Blake wrote:
>> On 7/4/19 1:38 PM, Thomas Weißschuh wrote:
>>> In filter/nozero a 64M large, static, zeroed, read-only array is declared.
>>> The new behavior of GCC puts this array as-is into the binary inflating the
>>> size by a factor of around 10000.
>>
>> Odd that you are only seeing this for the nozero filter, since we also
>> have the same sort of buffer in server/plugins.c.  Oh, I see a
>> difference between the two - one is function-local, the other is
>> file-local.  Does this patch make a difference? (I need to fire up a
>> rawhide VM to test it myself...)

Thanks for your fast reply - you did beat me in getting my rawhide VM
running.

> It actually also happens for server/plugins.c.

Good to know. So the fix is indeed removing 'const', rather than
reducing scope (although I might as well reduce scope while at it, for
consistency).

The fix is in git now.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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