rustc_target/spec/targets/
wasm32_unknown_unknown.rs

1//! A "bare wasm" target representing a WebAssembly output that makes zero
2//! assumptions about its environment.
3//!
4//! The `wasm32-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//!
10//! This target is more or less managed by the Rust and WebAssembly Working
11//! Group nowadays at <https://github.com/rustwasm>.
12
13use crate::spec::{Cc, LinkerFlavor, Target, base};
14
15pub(crate) fn target() -> Target {
16    let mut options = base::wasm::options();
17    options.os = "unknown".into();
18
19    options.add_pre_link_args(
20        LinkerFlavor::WasmLld(Cc::No),
21        &[
22            // For now this target just never has an entry symbol no matter the output
23            // type, so unconditionally pass this.
24            "--no-entry",
25        ],
26    );
27    options.add_pre_link_args(
28        LinkerFlavor::WasmLld(Cc::Yes),
29        &[
30            // Make sure clang uses LLD as its linker and is configured appropriately
31            // otherwise
32            "--target=wasm32-unknown-unknown",
33            "-Wl,--no-entry",
34        ],
35    );
36
37    Target {
38        llvm_target: "wasm32-unknown-unknown".into(),
39        metadata: crate::spec::TargetMetadata {
40            description: Some("WebAssembly".into()),
41            tier: Some(2),
42            host_tools: Some(false),
43            std: Some(true),
44        },
45        pointer_width: 32,
46        data_layout: "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20".into(),
47        arch: "wasm32".into(),
48        options,
49    }
50}