[Docs] Add some Rust docs #14394
[Docs] Add some Rust docs #14394
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| emsdk install 56b877afe7d1b651d6b9a2ba5d5df074876172ff | ||
| emsdk activate 56b877afe7d1b651d6b9a2ba5d5df074876172ff |
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It would be worth finding and documenting the first tagged Emscripten release after this point, IMO, rather than suggesting that users install an untagged release. A priori, I would expect that the risk of LLVM incompatibilities would be outweighed by the downsides of documenting an untagged git commit, namely that the commit is impossible to remember and raises questions about stability for users who do not know about our release process.
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This is the hash of a roll, so it has passed the roller's full test suite. For that reason I don't think the risk is significantly higher than a release.
It worries me to allow several further rolls in between (which is what going to the next release would cause). It's not just LLVM incompatibilities, it's binaryen as well, where LLVM and binaryen overlap (say, on the binary format of a new feature).
I think the minimal possible distance in terms of commits, that is still fully tested, is safest.
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As far as I understand, we can add arbitrary tags to hashes in emsdk pretty easily. Could we add a tag for this version like rust-1.52.1 or llvm-12 to make it easier to use & remember? At least until we automate this, it seems useful to have human-readable names.
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Looks like it just needs a tag here? https://github.com/emscripten-core/emsdk/blob/main/emscripten-releases-tags.txt
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Good idea! Yes, it is as simple as that.
+1 for adding both of those tags there, as both could be useful for people wanting to use emscripten with a provided LLVM.
We should also test them. Testing the LLVM one can be done with a PR in emscripten (that replaces the tot build with LLVM 12). For Rust, I'm not sure how best to do it, but one option might be to create an emscripten-core/rust repo and add some amount of testing there. Or perhaps the repo could be more generically named, as we may want multiple languages there eventually (e.g. Zig).
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Yes, it is as simple as that.
(narrator voice) It wasn't as simple as that 😅 emscripten-core/emsdk#836
| (For more on how to find the proper Emscripten hash for a particular LLVM | ||
| commit, see our | ||
| `release process docs <https://github.com/emscripten-core/emscripten/blob/main/docs/process.md#release-processes>`_ | ||
| which are summarized in the | ||
| :ref:`developer's guide <developers-guide-bisecting>`.) |
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I don't think we should be recommending these docs to end users, even parenthetically. We should make using Rust with Emscripten appear as simple as possible.
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I'd be happy to remove it to a lower section "for advanced users" or such? I do think there is value for the type of developer that does want to know how things work internally.
These are human-readable tags for emscripten-core/emscripten#14394 (comment). I went with `rust-compat` instead of `rust` because `emsdk install rust` might be confusing and suggest that it will install Rust itself too.
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Btw, checking this again, I'm not sure we did it right. The LLVM change here is when trunk was switched to report itself as 12 - which was a year ago. Is that what Rust uses currently? (Or does Rust use one of the release candidates for LLVM 12, which would be many months later?) |
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@kripken As far as I can tell, Rust currently uses LLVM 12 build from April: Because there are some custom patches involved, it's a bit hard to tell which specific upstream LLVM hash it corresponds to, but the fork with list of commits is here: https://github.com/rust-lang/llvm-project/commits/rustc/12.0-2021-04-15 |
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April 2021? That's very different than the LLVM revision @tlively pointed to, which was from July 2020 (almost a year ago), https://github.com/llvm/llvm-project/releases/tag/llvmorg-12-init So seems like we need to figure this out... It's very hard for me to see what's going on in those last links. April 15 2021 is in the branch name, but there is nothing special about that date in the history - it has commits both before and after that date that do not seem to correspond to upstream LLVM (or that are cherry-picks from it). |
Yeah I think they cherry-pick occasional fixed, e.g. whenever they find yet another bug related to |
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This commit in April seems telling at least - might try to use it as a sync point: rust-lang/llvm-project@757752f |
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Aha, I was confused about the tags. I thought that llvmorg-12-init would be the base commit for the line of LLVM 12 release candidates, but it's actually the commit where they first bumped the trunk version number to 12 and started making changes that wouldn't appear in LLVM 11. So the tag we need to look for to find the closest mainline match to LLVM 12 is actually llvmorg-13-init. |
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