rules_rust VS mold

The same reason Bazel builds avoid using Cargo when building Rust software, so I'll describe why Bazel would do this:

- Bazel wants to cache remote resources, like each respective crate's source files.

- Bazel then wants to build each crate in a sandbox, and cache the build artifacts

This is an established practice, and Nix wants to drive the build for the same reasons.

See:

- https://github.com/bazelbuild/rules_rust

- https://github.com/google/cargo-raze

To answer your question, I don't know if Soong or Bazel can reuse the files produced by an incremental Rust compilation. I tried searching the rules_rust repository and found some discussions, but nothing that clearly told me "Yes, this is supported".

Bazel doesn't allow targeting a lot of platforms (especially embedded) from Rust, even when the Rust ecosystem supports these targets. Something is off with its design if new work needs to be done for every platform that's already available behind an interface that's as consistent as what rustc gives.

What is supported needs to be inferred from this file, as far as I can tell: https://github.com/bazelbuild/rules_rust/blob/main/rust/plat...

You might be overjoyed to learn that you can use a build tool that forces you to manually write out the dependencies between each file.

I am using rules_rust and have the VS Code Bazel plugin installed, but I am still not getting autocomplete.

Other than that, the performance of both for builds should be determined exactly by the organization of code into separate crates and the rustc invocations. Bazel generally encourages smaller crates, but that's very subtle. There is at least 1 case I can think of where rustc is overfit to cargo, in a way that is not easily replicable by bazel, which is the metadata/rlib pipelining https://github.com/bazelbuild/rules_rust/issues/228

Rust integrates pretty seamlessly into Bazel projects via rules_rust (https://github.com/bazelbuild/rules_rust). The existing rules even allow for c calling rust and rust calling c. Example: https://github.com/bazelbuild/rules_rust/blob/main/examples/...

With any compiled language you can use the compiler and vendor your dependencies instead of using the language's conventional package manager. For example, nothing prevents skipping Cargo and building Rust directly with rustc the way Bazel does.

https://github.com/bazelbuild/rules_rust

I think this is unlikely to gain traction. I say that no to discourage you, just to explain.

- The community has an instinctive distrust of closed source or a compiler from an untrusted source. If you’re familiar with the Trusting Trust attack you’ll understand why.

- Dev tools in every language ecosystem are almost always free, unless they involve some kind of hosting. People aren’t used to opening their wallets. Look the experience of the guy who built the mold linker(https://github.com/rui314/mold). Far superior to the state of art, improves incremental compiles a lot, widely applicable across ecosystems (C, C++, Rust), CPU architectures and Operating Systems. You don’t even have to modify your compiler, just need to point to his linker. He’s even giving it away for free for personal use. But still, almost no one uses it. The inertia of the established options is really high.

- It’s not complex enough. Think about the complexity involved in the cranelift backend. No one can seriously recreate the efforts of bjorn3. If we could have, we would have. But the idea idea here can be recreated, especially by the experts who already built incremental compilation into rustc.

- But if your solution is truly complex, like the parallel frontend, the burden of maintaining a fork would be too high. You’d have to spend all your time rebasing.

Again I’m not trying to discourage you, just stating the difficulties of making a business in the dev tools space. You would be better off contributing this excellent work to the community and trying a different tack.

I initially thought this would be about the mold linker (https://github.com/rui314/mold)

I assume this submission is trying to highlight the specific message (2023-01-24) : https://github.com/rui314/mold/issues/190#issuecomment-14028...

Fyi... the author wrote a more expansive blog post about selling dev tools a few months later (2023-06-06) and there was a related HN thread about it: https://news.ycombinator.com/item?id=36225016

Loongson's LoongArch CPU has been supported. (03b1a1c)

I'm amazed at how quickly the author responds to requests: https://github.com/rui314/mold/issues/1057

From the report to the fix in less than two days.

I'm not sure how competitive it will be with lld, especially if we consider ThinLTO (which takes multiple minutes on 64-core machine) - it can make the advantages of mold insignificant.

What other solutions have you tried for the problem of slow linking? You haven't even said which linker and what flags you're using. I haven't actually tried it, but the author of gold has an even faster linker called mold: https://github.com/rui314/mold

> Mold did it first, though: https://github.com/rui314/mold

Before LLD?