FWIW, ORC was specifically designed to be efficient, but it was not designed to be future-proof against complex toolchain changes. Since all the ORC tooling is in the kernel, it can evolve together if needed.
(I was a bit involved in the design — I helped optimize the first to reduce cache misses on lookup.)
That's not true at all. It's in some very rare cases. Firefox I think at this point ships with framepointers enabled and so does every M1/M2 mac app and all iOS applications as it's mandatory for the calling convention on Apple.
Phoronix [3] did a test of "-fno-omit-frame-pointer" during the discussion on whether to enable the flag for Fedora, this time on x86-64. They found an average 14% performance hit on a wide variety of benchmarks.
[1] https://www.kernel.org/doc/html/latest/x86/orc-unwinder.html [2] https://lore.kernel.org/all/20170602104048.jkkzssljsompjdwy@... [3] https://www.phoronix.com/review/fedora-frame-pointer/5
In any case, the runtime performance hit of frame pointers is quite high, and since we do have things like DWARF (and maybe ORC someday?), I’d still argue that frame pointers aren’t necessary. It’s nice to have that extra register free!