chore: shrink CrelIteratorHeader struct size

[marxin]

As discussed here davidlattimore/wild#1396 - we can easily shrink the CrelIterator by 16 bytes from 80B to 64B.

[philipc]

This is fine, but also CrelIteratorState::index is unnecessary. We could modify CrelIteratorHeader::count as we iterate instead. And once we do that, CrelIteratorState is identical to Crel so we should just use that instead.

However, I think you should try to design wild so that needing significant numbers of the CrelIterator is unnecessary. You should be storing CrelIterator::data and CrelIterator::header at most once per SHT_CREL section. If you need to be able to start iteration at an arbitrary point in the section the additional information you need is the offset, number of relocations, and previous Crel, which I think comes to 40 bytes.

[marxin]

This is fine, but also CrelIteratorState::index is unnecessary. We could modify CrelIteratorHeader::count as we iterate instead. And once we do that, CrelIteratorState is identical to Crel so we should just use that instead.

Great idea!

However, I think you should try to design wild so that needing significant numbers of the CrelIterator is unnecessary. You should be storing CrelIterator::data and CrelIterator::header at most once per SHT_CREL section. If you need to be able to start iteration at an arbitrary point in the section the additional information you need is the offset, number of relocations, and previous Crel, which I think comes to 40 bytes.

Yeah, I know. To be honest, right now, once we need a slice of relocations with CRel, we allocate a vector and store there the entire content of the relocation sections. That's a no-go for the future - I've got an idea how to make it smarter.