[Bug sanitizer/63927] AddressSanitizer painfully slow on ppc64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63927

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Kostya Serebryany from comment #4)
> Why can't we use frame pointers on PPC? 


You don't need to use the frame pointer.  The ABI says the stack frame always
contains a reference to the previous frame at a specific location (I think
sp+0). 

> So far I have not seen any implementation of unwinder not based on FPs
> that was fast enough for ASan. 
> ASan unwinds the stack on every malloc/free and thus it is very sensitive to
> the unwinder performance.