On Fri, 2022-04-08 at 15:36 -0400, David Malcolm wrote: > I'm excited to read that rustc_codegen_gcc, the libgccjit-based > backend > for rustc can now bootstrap rustc: > https://blog.antoyo.xyz/rustc_codegen_gcc-progress-report-10 > > I've been focusing on the analyzer, and so haven't been as on top of > libgccjit patch review as I should have been. Sorry about that. > > rustc_codegen_gcc currently recommends that people build their own > libgccjit, as it contains a number of patches that aren't in gcc > trunk > yet. > > We're deep in "stage 4" of gcc 12, but libgccjit is a relatively > self- > contained part of the project, so I'm wondering if it makes sense to > try to get all/some of these patches into gcc 12. > > Antoyo: your email of: > https://gcc.gnu.org/pipermail/jit/2022q1/001475.html > said: > > [..snip...] > > > Ok, if the 4 patches currently being reviewed (and listed here: > > https://github.com/antoyo/libgccjit-patches) were included in gcc > > 12, > > I'd be able to build rustc_codegen_gcc with an unpatched gcc. > > > > It is to be noted however, that I'll need more patches for future > > work. > > Off the top of my head, I'll at least need a patch for the inline > > attribute, try/catch and target-specific builtins. > > The last 2 features will probably take some time to implement, so > > I'll > > let you judge if you think it's worth merging the 4 patches > > currently > > being reviewed for gcc 12. > > > > Are users of rustc_codegen_gcc still likely to need to build their > own > libgccjit even if we got all of the following into gcc 12? If so, > then > it's probably best to wait. >
I was talking to Josh Triplett (co-load of the Rust language team) about this and the idea was that if we could have a feature-gated rustc_codegen_gcc that works with gcc 12, we could start doing the infrastructure work in rustup to start distributing rustc + libgccjit.so to users, as an early preview. So, yes if users want to experiment with the latest changes of rustc_codegen_gcc, they will have to build libgccjit from source. The benefit of having those patches in gcc 12 would mostly be to start this infrastructure work. > > Jakub/Richi (as release managers): how would you feel about me > pushing > some of these libgccjit-specific patches into trunk deep in stage 4? > I > believe the risk is low, though I should note that I'm going on > vacation on 18th through 22nd April and won't have access to my > computer that week. > > > Looking at https://github.com/antoyo/libgccjit-patches I see 5 > patches. > That said, all but the last one refer to .c source files and so > predate > the big .c to .cc migration of the gcc source tree. So it looks like > the patches in that repo may need refreshing. I updated them just now. > > More detailed status: > > [PATCH] Add support for sized integer types, including 128-bit > integers > [PR95325] > Most recent discussion is here: > https://gcc.gnu.org/pipermail/jit/2021q2/001303.html > My notes say that I'm waiting on an updated version of patch > addressing the issues in that review. Was there one? Yes, there was one and I just sent it again on the mailing list. > > > [PATCH] libgccjit: Add support for bitcasts [PR104071] > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104071 > Most recent discussion seems to be > https://gcc.gnu.org/pipermail/jit/2022q1/001475.html > I've just now posted a review of that version; LGTM with some nits, > though it adds a trivial tree_cc_finalize which I'm strictly speaking > not a maintainer of. > > > [PATCH] libgccjit: Add support for register variables [PR104072] > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104072 > Review thread: https://gcc.gnu.org/pipermail/jit/2022q1/001466.html > Latest patch seems to be: > https://gcc.gnu.org/pipermail/jit/2022q1/001510.html > My recollection is that the jit parts of the patch look OK, but > this > adds a (trivial) new reginfo_cc_finalize which would thus need > approval > from an RTL maintainer. > > > [PATCH] libgccjit: Add option to hide stderr logs [PR104073] > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104073 > Review thread: https://gcc.gnu.org/pipermail/jit/2022q1/001469.html > Latest patch: https://gcc.gnu.org/pipermail/jit/2022q1/001480.html > I approved https://gcc.gnu.org/pipermail/jit/2022q1/001483.html > This looks ready to go, assuming release managers are happy. > > > [PATCH] libgccjit: Add support for setting the alignment [PR104293] > https://gcc.gnu.org/pipermail/jit/2022q1/001494.html > I've just now posted a review of that patch; some minor changes > needed. > > So I think I'm waiting on an updated version of the sized-integer- > types > patch, and some nit-fixes for the other patches (but am disappearing > on > vacation on 18th - 22nd). I'll update the patches to address your review over the weekend. Thanks! > > > Hope the above makes sense; sorry again for not getting to these > patches sooner. > > Dave > >
