https://github.com/huonw/boehm-rs

https://github.com/huonw/boehm-rs

Last synced: about 1 month ago
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• Host: GitHub
• URL: https://github.com/huonw/boehm-rs
• Owner: huonw
• Created: 2014-01-01T15:15:12.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2016-09-21T12:15:13.000Z (about 8 years ago)
• Last Synced: 2023-04-10T09:38:34.003Z (over 1 year ago)
• Language: Rust
• Homepage: http://huonw.github.io/boehm-rs/boehm/
• Size: 479 KB
• Stars: 10
• Watchers: 4
• Forks: 5
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# Using the Boehm GC from Rust

[![Build Status](https://travis-ci.org/huonw/boehm-rs.png)](https://travis-ci.org/huonw/boehm-rs)

A basic wrapper that provides `Gc` and `GcTracing` types

(completely conservative and precise-on-heap respectively),

implemented by binding to the

[Boehm-Demers-Weiser garbage collector](http://www.hpl.hp.com/personal/Hans_Boehm/gc/). See

`examples/` for some examples.

## Warning

This is not correct and shouldn't be used/should only be used very

carefully, because I don't think the Rust compiler provides enough

hooks yet to make something like `~[Gc]` completely work.

To illustrate, the following program is trying to make a vector

`~[Gc 0, Gc 1, ..., Gc 1_000_000]`, so it should print `0`... but it

prints `895221` for me; the vector doesn't act as a root that Boehm

can understand, and so it's free to GC the first one and reuse that

memory for one of the later allocations. Oops.

```rust

extern mod boehm;

#[start]

fn main(_: int, _: **u8) -> int {

    boehm::init();

    let mut v = std::vec::from_fn(1_000_000, boehm::Gc::new);

    println!("{}", *v[0].borrow());

    0

}

```

I think this could be somewhat fixed with some trickery with

`#[no_std]` and `#[lang="malloc"]` and so on, but that's beyond the

time I've been able to allocate (no pun intended) to this so far.

## Todo

- Fix the above

- Stop generating the Boehm type-descriptor for each type on every

  allocation (requires compiler support to do properly, but we could

  cache based on the address of the (Rust) type descriptor, or

  something)

## Todo-done

- Use

  [the typed inferface](http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc_typedh.txt)

  for more precise collection (at the very least, working out a way to

  use malloc_atomic where appropriate would be good). See [`boehm::tracing`](http://huonw.github.io/boehm-rs/boehm/tracing/index.html).

## License

Dual Apache v2.0 and MIT, like Rust itself.