<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">Le 6 juin 2018 à 22:37, Rui Ueyama <<a href="mailto:ruiu@google.com" class="">ruiu@google.com</a>> a écrit :</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div class="gmail_quote"><div dir="ltr" class="">On Wed, Jun 6, 2018 at 11:41 AM Brian Gesiak <<a href="mailto:modocache@gmail.com" class="">modocache@gmail.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr" class="">Thanks for the response, Rui!<div class=""><div class="gmail_extra"><br class=""><div class="gmail_quote">On Tue, Jun 5, 2018 at 5:26 PM, Rui Ueyama <span dir="ltr" class=""><<a href="mailto:ruiu@google.com" target="_blank" class="">ruiu@google.com</a>></span> wrote:<blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr" class="">Besides the features you pointed out, I think Xcode introduced a new way of listing dynamic linking symbols, and I believe lld doesn't support that.</div></blockquote><div class=""><br class=""></div><div class="">.tbd files, is that right? A colleague of mine pointed me to Apple's libtapi open source project [1], maybe I can learn more about these files from that library. In fact, there's been discussion about bringing libtapi to LLVM on the mailing list in the past, although I don't know if anything came of it. [2]</div><div class=""><br class=""></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr" class="">I think the real issue is the lack of maintenance and ownership of the mach-O lld tree. There's no activities for the tree for years, though we've been making efforts to keep it compile and pass all the existing tests.</div></blockquote><div class=""><br class=""></div><div class="">Excellent, thanks for letting me know. This doesn't bother me, I'm happy to try contributing to it as best I can! I would also appreciate, as your time permits, whatever guidance you can provide. For example, benefitting from several years of hindsight, would you recommend keeping the ATOM-based lld approach? [3] Prior emails discussed moving Mach-O lld away from ATOM. [4] Has the success of ELF and COFF influenced your thinking on this in the years since, or is ATOM probably still the best fit for Mach-O?</div></div></div></div></div></blockquote><div class=""><br class=""></div><div class="">That's a good question. There was a big discussion as to the design of the new (now current ELF/COFF/wasm) and the ATOM-based lld a few years ago when I started working on the new one. At the time no one including me was really sure what design is desirable, and I was exploring the design space to something good. Today, we have three working, high-performance linkers for ELF, COFF and wasm based on the new design, which I think proves the design; it is easy to add new features, easy to understand, and it delivers what users want the most (i.e. speed). Given that, if I were you, I'd try to see if the new lld's design fits mach-O. You may need to tweak the design a little bit, but I'd imagine that the difference is not as significant as between ELF and wasm (which has a different concept of memory address space mainly for security). I'd also like to get input from Apple engineers as well.</div></div></div></div></blockquote><br class=""></div><div>I don’t remember but I think one of the main point was that EFL and Mach-O don’t have the same concept of section. IIRC, the concept of section in ELF was closer to the atom model than with Mach-O which uses few sections and put a lot of things in each one.</div><div><br class=""></div><div>And a quick search gave me that: <a href="http://llvm.1065342.n5.nabble.com/LLD-improvement-plan-td80788.html#a80871" class="">http://llvm.1065342.n5.nabble.com/LLD-improvement-plan-td80788.html#a80871</a></div><div><br class=""></div><div><br class=""></div><div><br class=""></div><br class=""></body></html>