On Thu, Apr 19, 2018 at 06:17:26PM +0100, Thomas Preudhomme wrote:
> For stack protector to be robust, at no point in time the guard against
> which the canari is compared must be spilled to the stack. This is achieved
> by having dedicated insn pattern for setting the canari and comparing it
> against the guard which doesn't reflect at RTL what is happening. However
> computing the address of the guard is done using standard movsi pattern and
> can thus be spilled (see PR85434). I'm reaching out to the community for
> ideas on how to avoid this.
Usually targets just put the canary into TLS area, then there is nothing to
spill.
Jakub
