W dniu pon, 02.04.2018 o godzinie 13∶27 -0400, użytkownik Joshua Kinard napisał: > On 4/2/2018 5:41 AM, Michał Górny wrote: > > W dniu nie, 01.04.2018 o godzinie 20∶40 -0700, użytkownik Matt Turner > > napisał: > > > > > My plan is to add stable 17.0 mips profiles when the keywording is > > > sorted out and kill two birds with one stone. > > > > Does it involve fixing the CHOST inconsistency so that we can finally > > get LLVM keyworded? > > Bug #515694, right? Based on a very quick re-read, there are two > issues/blockers here: > > 1) Current Gentoo/MIPS support was originally based on gcc, thus, we've used > CHOST tuples that are recognized by gcc.
As far as I'm aware GCC doesn't really care about which triplet is used. It's all controlled by --with-abi= option (I may have mistyped its name). > 2) clang lacks a CHOST tuple that defaults to n32. n32 is the "ideal" ABI for > a 64-bit platform that doesn't need full 64bit (n64) binary support. > > As far as I can tell, we need to fix #2 before we can do anything about #1. > Once clang has a discrete CHOST tuple for n32, that'll put it on parity with > gcc, which itself appears to have a batch of more specific tuples to select > different ABIs. You might want to just push upstream any patches you have > that > adds this support first. It's chicken-egg problem. Before I can submit a patch upstream, I need someone with MIPS hardware and a proper profile (using disjoint, consistent triplets) to test it. Not to mention Gentoo needs to decide on the triplet in the first place. > > --- > > Having been around in the Very Beginning, I can tell you that one doesn't > change CHOSTs lightly on MIPS. There are a LOT of upstream projects that > don't > use newer autotools and thus won't recognize the more specific CHOSTs. And > there are a few projects, like Perl, that use their own custom build system > and > might need special fixes on top to use the more-specific tuples. > > That said, none of this addresses the issue of the multiple C library options > available. As far as I know, using different ABIs with uclibc-ng or musl > requires setting either a build or config option, or passing -mabi=xxx, along > with a gcc-like CHOST tuple. E.g., for my uclibc-ng chroot on my Octane, I am > sticking w/ o32 and thus use a CHOST of mips-unknown-linux-uclibc. If > clang/llvm can co-exist with C libraries other than glibc, this is likely an > additional complexity to consider. > > Also, last I checked, clang/llvm didn't have full support for the "old" MIPS > ISAs, namely mips3 and only part of mips4. It also has no knowledge of > scheduling for the old CPU families, like R10K. I helped write the current > R10K scheduling code for gcc a few years ago, so maybe could do something for > clang/llvm, though I have no idea how they implement CPU scheduling logic. > -- Best regards, Michał Górny
