[lld] r286100 - [ELF] Make InputSection<ELFT>::writeTo virtual

[Rafael Espíndola via llvm-commits]

On 8 November 2016 at 07:00, Eugene Leviant <evgeny.leviant at gmail.com> wrote:
> VMTs themselves are not allocated (AFAIK they're stored in .rodata),
> so I guess the problem is in extra 4/8 bytes of VMT pointer size and
> overhead
> for initialization, correct?

Yes, in each input section.

> For dyn_cast you have extra 4 bytes for
> Kind + function call + compare-and-branch. Can you provide some
> proofs, that it is faster?
> (like you did in your previous letter).

The SectionKind only uses 3 bits in the input section. Really, the
issue is sizeof(InputSection<ELFT>). We are quite bounded by memory
access, so compacting structures is an important optimization.

Do you have an ETA? Would you mind reverting the patch for now?

Cheers,
Rafael