add mips64-gnu and mips64el-gnu targets
With this commit one can build no_core (and probably no_std as well)
Rust programs for these targets. It's not yet possible to cross compile
std for these targets because rust-lang/libc doesn't know about the
mips64 architecture.
These targets have been tested by cross compiling the "smallest hello"
program (see code below) and then running it under QEMU.
``` rust
extern {
fn puts(_: *const u8);
}
fn start(_: isize, _: *const *const u8) -> isize {
unsafe {
let msg = b"Hello, world!\0";
puts(msg as *const _ as *const u8);
}
0
}
trait Copy {}
trait Sized {}
```
cc #36015
r? @alexcrichton
cc @brson
The cabi stuff is likely wrong. I just copied cabi_mips source and changed some `4`s to `8`s and `32`s to `64`s. It was enough to get libc's `puts` to work but I'd like someone familiar with this module to check it.
implementing RFC 1623. This fixes#35897.
This is a work in progress. In particular, I want to add more tests,
especially the compile-fail test is very bare-bones.
Implement RFC 1560 behind `#![feature(item_like_imports)]`
This implements https://github.com/rust-lang/rfcs/pull/1560 (cc #35120) behind the `item_like_imports` feature gate.
The [RFC text](https://github.com/rust-lang/rfcs/blob/master/text/1560-name-resolution.md#changes-to-name-resolution-rules) describes the changes to name resolution enabled by `#, it improves performance quite a bit:
| phase | before | after |
| ----- | ------ | ----- |
| collection | 0.79s | 0.46s |
| translation | 6.8s | 3.2s |
| total | 11.92s | 7.15s |
r? @arielb1
Allow specification of the system V AMD64 ABI constraint.
This can be specified using `extern "sysV64" fn` on all platforms.
This ABI is used as the C ABI on unix platforms, but can only be specified there using extern "C". It was impossible to specify on other platforms. Meanwhile the win64 ABI, which was the extern "C" ABI on the windows platform could be specified on other platforms using extern "win64".
This pull request adds the the "sysV64" ABI constraint which exposes this calling convention on platforms where it is not the C ABI.
