List all available ABI strings in reference.md

[liigo]

No description provided.

[nagisa]

Thing with these “ABI strings” is that its dubious how many of them we want to consider stable. C is obvious as are microsoft’s ABIs… but everything else… shrugs?

[steveklabnik]

/cc @rust-lang/lang

[liigo]

extern "foo" {}

fn main() {
}

rustc may prints all available abi:

<anon>:1:8: 1:13 error: invalid ABI: expected one of [cdecl, stdcall, fastcall, vectorcall, aapcs, win64, Rust, C, system, rust-intrinsic, rust-call, platform-intrinsic], found `foo`
<anon>:1 extern "foo" {}
                ^~~~~
error: aborting due to previous error

[jethrogb]

For reference, the LLVM supported calling conventions are http://llvm.org/docs/doxygen/html/namespacellvm_1_1CallingConv.html and the rust calling conventions are

rust/src/libsyntax/abi.rs

Lines 81 to 100 in c66d238

	const AbiDatas: &'static [AbiData] = &[
	// Platform-specific ABIs
	AbiData {abi: Abi::Cdecl, name: "cdecl" },
	AbiData {abi: Abi::Stdcall, name: "stdcall" },
	AbiData {abi: Abi::Fastcall, name: "fastcall" },
	AbiData {abi: Abi::Vectorcall, name: "vectorcall"},
	AbiData {abi: Abi::Aapcs, name: "aapcs" },
	AbiData {abi: Abi::Win64, name: "win64" },
	// Cross-platform ABIs
	//
	// NB: Do not adjust this ordering without
	// adjusting the indices below.
	AbiData {abi: Abi::Rust, name: "Rust" },
	AbiData {abi: Abi::C, name: "C" },
	AbiData {abi: Abi::System, name: "system" },
	AbiData {abi: Abi::RustIntrinsic, name: "rust-intrinsic" },
	AbiData {abi: Abi::RustCall, name: "rust-call" },
	AbiData {abi: Abi::PlatformIntrinsic, name: "platform-intrinsic" }
	];

[strega-nil]

I think that "Rust" and "C" calling conventions should be declared standard Rust, i.e., any Rust compiler has to at least have the "Rust" calling convention (of course), and the "C" calling convention (in order to compile as much code as possible, and to interop with C/other languages); however, I think the other calling conventions should be rustc specific. These are the safest ABIs we can reasonably say are probably everywhere.

[jethrogb]

@ubsan Also "system"

[strega-nil]

@jethrogb I don't know if "system" should be required by every compiler. "Rust" and "C" seem far more universal, whereas "system" only does anything on x32 Windows.

Might be enough code uses "system" to justify its inclusion, however.

[brson]

Removed the easy tag since there's no agreement about what to document.

[strega-nil]

Fixed by #34461