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Toy lang can call puts function in libc. How to call a function writen by Rust?

Thanks a lot!

Taken from #37:

• there are a few links to an old version of the cranelift-module crate, for Module and Backend for instance.
• ditto for cranelift-frontend
• integer constants is linking to the readthedocs documentation, which is out of date. We should instead link to the IR descriptions (that live here).
• the links to line numbers of the example programs foo and iterative_fib are off by one.
• the link to github issues at the bottom is broken and should link to the bytecodealliance/cranelift repository instead.

As a policy, the Bytecode Alliance is changing the default branch names in all repositories. We would like for all projects to change the default to main by June 26. (We mention June 26th because there is some suggestion that GitHub may be adding the ability to make this process more seamless. Feel free to wait for that, but only up to June 26. We'll provide further support and documentation before that date.)

Please consider this a tracking issue. It is not intended for public debate.

• Change branch name
• Update CI
• Update build scripts
• Update documentation

At first, I appreciate your great effort, thank you for this nice demo of cranelift-jit.
I love this demo a lot.

My question is, it seems that functions are called with input of tuple. For example, (1, 0) is passed as arguments in the call below.

But tuple's number of elements cannot be defined dynamically. Let's say, a user defines a function with 5 arguments, then Rust program must supply a tuple of 5 elements as an input (arguments) to run the function.

But Rust program cannot know how many arguments a user defines for a function before compilation, so I think it is impossible to define them as tuple. So how can I pass such arguments to a function?

I know you can print the cranelift IR with ctx.func (#55), but is there a way to print the generated x86 instructions before or after the module.finalize_definitions() line? I want to see the final code that gets generated so I can debug issues with it and perhaps optimize the IR I'm generating.

Thanks!

This demo is great, so I'm enjoying creating some software with this, but currently I'm struggling to get type of "Value" of cranelift. How can I check if string is inside or if number is inside Value? Or can we use this immediate instead of Value?

In the example provided, the function signature for the to-be compiled code-string must be known in advance in order to be able to call into the function properly.

https://github.com/CraneStation/simplejit-demo/blob/4b7b8099346d877fe559dd5b593b18344d62e30d/src/toy.rs#L47

Is it possible to make a call dynamically using an array of parameters instead of being required to mem::transmute to the correct function signature?

For example, write a simple print function which can be called from compiled code to print a value.

cc bytecodealliance/cranelift#1280

I want to learn from the generated IR, how can I print it out?

Thanks

my OS: Fedora 33,
Rust: 1.49.0

so when I do cargo run in "cranelift-jit-demo-main" it compiles but then:

thread 'main' panicked at 'unable to make memory readable+executable: SystemCall(Os { code: 13, kind: PermissionDenied, message: "Permission denied" })', /home/adsick/.cargo/registry/src/github.com-1ecc6299db9ec823/cranelift-simplejit-0.68.0/src/memory.rs:197:30
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

why is it so and how do I fix it (or rather it should be fixed somewhere in the actual project, I dunno)

I've been trying to create a fixed length of memory and load from it. I keep getting

terminated by signal SIGSEGV (Address boundary error)

If you could add an example showing such a usecase it would be very helpful.

bytecodealliance/wasmtime#2479

The code and docs should be updated to reflect this change.

How can I disable the access to libc using dlysm?
Thanks,
Dominik

Hi,

I am writing an in browser application via Rust compiled to wasm. In this in-browser application, I would like to be able to dynamically generate code and call it. Is it possible to do this via cranelift-simplejit ? [I am having problem building it for the wasm32-unknown-unknown target.]

Thanks!

I removed the assert to see that the demo does work in Windows. I haven't dug in further to see why it works, but figured I'd share.

Error when compile on linux with
cranelift-jit = { version = "0.79", features = ['selinux-fix'] }
With versions 0.77, 0.78 also not compiled.

error[E0308]: mismatched types
--> /home/ali/.cargo/registry/src/github.com-1ecc6299db9ec823/cranelift-jit-0.79.0/src/memory.rs:37:9
|
35 | fn with_size(size: usize) -> io::Result {
| ---------------- expected std::result::Result<PtrLen, std::io::Error> because of return type
36 | let alloc_size = region::page::ceil(size);
37 | / MmapMut::map_anon(alloc_size).map(|mut mmap| {
38 | | // The order here is important; we assign the pointer first to get
39 | | // around compile time borrow errors.
40 | | Ok(Self {
... |
44 | | })
45 | | })
| |__________^ expected struct PtrLen, found enum std::result::Result
|
= note: expected enum std::result::Result<PtrLen, _>
found enum std::result::Result<std::result::Result<PtrLen, _>, _>

Hello, I am a beginner wasm
how do I concatenate strings? Send string？in this jit-demo

as the title says. Do you have to compile them individually and then use indirect call? or is there some other way of doing it?