Debian, Rust, and librsvg

Posted Nov 14, 2018 16:18 UTC (Wed) by mathstuf (subscriber, #69389)
In reply to: Debian, Rust, and librsvg by glaubitz
Parent article: Debian, Rust, and librsvg

> so I guess many projects will build just fine with mrustc.

mrustc ignores lifetimes completely, assuming that they are correct. Granted, for released code, this is probably fine, but I certainly wouldn't want to apply a patch to a project without checking with rustc first.

Debian, Rust, and librsvg

Posted Nov 14, 2018 16:30 UTC (Wed) by glaubitz (subscriber, #96452) [Link] (3 responses)

> mrustc ignores lifetimes completely, assuming that they are correct. Granted, for released code, this is probably fine, but I certainly wouldn't want to apply a patch to a project without checking with rustc first.

Yes, I'm aware of that. But I wouldn't use mrustc for developing code either. Just for building release code.

Debian, Rust, and librsvg

Posted Nov 14, 2018 16:36 UTC (Wed) by josh (subscriber, #17465) [Link] (2 responses)

I wouldn't use it for that either, especially if code might vary across architectures. And if you follow dependencies down to the leaves of the dependency tree, you'll often find some code that does.

Also worth noting: mrustc currently has far less portability than Rust, and I don't see any signs of changing that.

Debian, Rust, and librsvg

Posted Nov 16, 2018 14:18 UTC (Fri) by glaubitz (subscriber, #96452) [Link] (1 responses)

> Also worth noting: mrustc currently has far less portability than Rust, and I don't see any signs of changing that.

Did you even try mrustc yourself or are you just guessing? It took me 5 minutes to make it build on m68k.

mrustc generates C code out of Rust code. How should it be **not** portable?

Debian, Rust, and librsvg

Posted Nov 16, 2018 21:13 UTC (Fri) by josh (subscriber, #17465) [Link]

Rust has its own conditional compilation mechanisms and target-specific mechanisms, as well as many other ways it needs to know about the details of the target platform. Going by way of C does not automatically make it perfectly portable. Quoting https://github.com/thepowersgang/mrustc/blob/master/READM... :

> - Supported Targets:
> - x86-64 linux
> - (incomplete) x86 windows
> - (incomplete) x86-64 windows

I based my comment on that. This isn't about the host platform of mrustc, it's about what the generated code targets, and using C as an intermediate language does not automatically make code portable.