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

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...) If it doesn't, then removing the 'const' seems like the easiest trick to work around this compiler pessimization (yes, I can see why the compiler writers argued that sticking things in .rodata adds a bit more security against errant code accidentally trying to corrupt the buffer; but as the buffer shouldn't be escaping, it's already undefined behavior for such code to happen).

diff --git i/filters/nozero/nozero.c w/filters/nozero/nozero.c index 16ec710b..21863707 100644 --- i/filters/nozero/nozero.c +++ w/filters/nozero/nozero.c ...