Re: alloca in inline functions can be dangerous

[Andreas Lausch-Waas <andreas () flausch at>]

On 2017-04-10 16:55, Leandro Pereira wrote:
> On Mon, Apr 10, 2017 at 7:36 AM, Jason A. Donenfeld <Jason () zx2c4 com> wrote:
> > I'm interested if anybody else has encountered this behavior or has any
> > thoughts about it.
> Yes, and I usually mark those functions with __attribute__((noinline))
> to avoid precisely this kind of behavior.

This (VLAs in loops or inlines filling the stack) would be a gcc bug: 
"Jumping or breaking out of the scope of the array name deallocates the 
storage. Jumping into the scope is not allowed; you get an error message 
for it.". See https://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html

At least GCC 6.3.1 does not call alloca for VLAs.


--
Andreas