teavm VS llvm-project

Joel from our team worked on the initial prototype for WASI support in TeaVM (https://github.com/konsoletyper/teavm/pull/610), and we temporarily forked before the WASI support made it to the official repo.

Good reminder to deprecate that now!

A number of concerns with the viability of the current WASM GC are covered here (Google translation to English):

https://habr-com.translate.goog/ru/articles/757182/?_x_tr_sl...

and the original article:

https://habr.com/ru/articles/757182/

This is from the author of TeaVM, who has 10 years of experience getting Java and JVM code to run efficiently in the browser. https://teavm.org/

TeaVM's existing transpilation of Java to JavaScript performs well (using the browsers JS GC). It will be interesting to see if WASM GC matures to the point where it is even faster.

Uses this apparently: https://github.com/konsoletyper/teavm

How does this compare to say the TeaVM (https://github.com/konsoletyper/teavm) which I know only has "experimental" WASM support at the moment?

For Java, no WASM file is requested. Maybe the Java code was transpiled to JavaScript, perhaps using TeaVM.

>> It's not like you can take a random JAR and convert it to WASM.

Maybe you can:

TeaVM is an ahead-of-time compiler for Java bytecode that emits JavaScript and WebAssembly that runs in a browser. Its close relative is the well-known GWT. The main difference is that TeaVM does not require source code, only compiled class files. Moreover, the source code is not required to be Java, so TeaVM successfully compiles Kotlin and Scala.

https://teavm.org/

I have never had an opportunity to try out TeaVM, but it seems promising.

For a fast, lightweight, Java-based front-end, try TeaVM and its Flavour toolkit:

https://teavm.org/

It is easy to get started by using the maven archtetype, there's an tutorial in Java Magazine here:

https://blogs.oracle.com/javamagazine/post/java-in-the-brows...

With TeamVM and Flavour you get a full front-end SPA framework that lets you code business logic in Java, and pair that with HTML and CSS to make components.

To see what it can do, check out Wordii, a fast-paced 5-letter word game:

> Someone will make the JRE run on WASM

https://teavm.org/

Minecraft contains some native dependencies, though; you'll need something like https://copy.sh/v86/ or https://bellard.org/jslinux/ with the right operating system image to run it in browser.

See

https://github.com/llvm/llvm-project/issues/88344

https://fortran-lang.discourse.group/t/flang-new-how-to-forc...

You can never mistake type_declaration with an identifier, otherwise the program will not work. Aside from that constraint, you are free to name them whatever you like, there is no one standard, and each parser has it own naming conventions, unless you are planning to use something like LLVM. If you are interested, you can see examples of naming in different language parsers in the AST Explorer.

> There is one way to make the LLVM JIT compiler more usable, but I fear it’s going to take years to be implemented: being able to cache and reuse compiled queries.

Actually, it's implemented in LLVM for years :) https://github.com/llvm/llvm-project/commit/a98546ebcd2a692e...

> It's true, this was a CVE in Rust and not a CVE in C++, but only because C++ doesn't regard the issue as a problem at all. The problem definitely exists in C++, but it's not acknowledged as a problem, let alone fixed.

Can you find a link that substantiates your claim? You're throwing out some heavy accusations here that don't seem to match reality at all.

Case in point, this was fixed in both major C++ libraries:

https://github.com/gcc-mirror/gcc/commit/ebf6175464768983a2d...

https://github.com/llvm/llvm-project/commit/4f67a909902d8ab9...

So what C++ community refused to regard this as an issue and refused to fix it? Where is your supporting evidence for your claims?

For everyone else looking for the magic in this almost 7k lines monster, look at line 6610 [1].

[1] https://github.com/llvm/llvm-project/blob/8ec28af8eaff5acd0d...

Through value tracking. It's actually LLVM that does this, GCC probably does it as well, so in theory explicit bounds checks in regular C code would also be removed by the compiler.

How it works exactly I don't know, and apparently it's so complex that it requires over 9000 lines of C++ to express:

https://github.com/llvm/llvm-project/blob/main/llvm/lib/Anal...

https://github.com/llvm/llvm-project/blob/main/flang/docs/F2...

• Go • Rust • Lua • pure C (sans C++) • 6502 assembly • WebAssembly • compiler backends, like LLVM or Cranelift

Compilers also may even spill data to stack from memory, even when the original location is still available, as can be seen in this issue: https://github.com/llvm/llvm-project/issues/53348

I vaguely remember that spilling like this could allow high-end CPUs to use something similar to register renaming, i.e. stack locations like [rsp + 96] could be stay in a physical registers during function execution (high-end CPUs often have more physical registers, than logical ones), but could find good references whether such optimization exists in practice or not.

Unfortunately, I think more often than note it causes performance regressions and in some cases it may even cause unnecessary stack spilling of sensitive data: https://github.com/rust-lang/rust/issues/88930#issuecomment-...