rustc_target/spec/targets/
wasm64_unknown_unknown.rs

1//! A "bare wasm" target representing a WebAssembly output that makes zero
2//! assumptions about its environment.
3//!
4//! The `wasm64-unknown-unknown` target is intended to encapsulate use cases
5//! that do not rely on any imported functionality. The binaries generated are
6//! entirely self-contained by default when using the standard library. Although
7//! the standard library is available, most of it returns an error immediately
8//! (e.g. trying to create a TCP stream or something like that).
9
10use crate::spec::{Cc, LinkerFlavor, Target, base};
11
12pub(crate) fn target() -> Target {
13    let mut options = base::wasm::options();
14    options.os = "unknown".into();
15
16    options.add_pre_link_args(
17        LinkerFlavor::WasmLld(Cc::No),
18        &[
19            // For now this target just never has an entry symbol no matter the output
20            // type, so unconditionally pass this.
21            "--no-entry",
22            "-mwasm64",
23        ],
24    );
25    options.add_pre_link_args(
26        LinkerFlavor::WasmLld(Cc::Yes),
27        &[
28            // Make sure clang uses LLD as its linker and is configured appropriately
29            // otherwise
30            "--target=wasm64-unknown-unknown",
31            "-Wl,--no-entry",
32        ],
33    );
34
35    // Any engine that implements wasm64 will surely implement the rest of these
36    // features since they were all merged into the official spec by the time
37    // wasm64 was designed.
38    options.features = "+bulk-memory,+mutable-globals,+sign-ext,+nontrapping-fptoint".into();
39
40    Target {
41        llvm_target: "wasm64-unknown-unknown".into(),
42        metadata: crate::spec::TargetMetadata {
43            description: Some("WebAssembly".into()),
44            tier: Some(3),
45            host_tools: Some(false),
46            std: None, // ?
47        },
48        pointer_width: 64,
49        data_layout: "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20".into(),
50        arch: "wasm64".into(),
51        options,
52    }
53}