cargo_test_support/
cross_compile.rs

1//! Support for cross-compile tests with the `--target` flag.
2//!
3//! Note that cross-testing is very limited. You need to install the
4//! "alternate" target to the host (32-bit for 64-bit hosts or vice-versa).
5//!
6//! Set `CFG_DISABLE_CROSS_TESTS=1` environment variable to disable these tests
7//! if you are unable to use the alternate target. Unfortunately 32-bit
8//! support on macOS is going away, so macOS users are out of luck.
9//!
10//! These tests are all disabled on rust-lang/rust's CI, but run in Cargo's CI.
11
12use std::env;
13
14/// The arch triple of the test-running host.
15pub fn native() -> &'static str {
16    env!("NATIVE_ARCH")
17}
18
19pub fn native_arch() -> &'static str {
20    match native()
21        .split("-")
22        .next()
23        .expect("Target triple has unexpected format")
24    {
25        "x86_64" => "x86_64",
26        "aarch64" => "aarch64",
27        "i686" => "x86",
28        _ => panic!("This test should be gated on cross_compile::disabled."),
29    }
30}
31
32/// The alternate target-triple to build with.
33///
34/// Only use this function on tests that check `cross_compile::disabled`.
35pub fn alternate() -> &'static str {
36    try_alternate().expect("This test should be gated on cross_compile::disabled.")
37}
38
39/// A possible alternate target-triple to build with.
40pub(crate) fn try_alternate() -> Option<&'static str> {
41    if cfg!(target_os = "macos") {
42        Some("x86_64-apple-darwin")
43    } else if cfg!(target_os = "linux") {
44        Some("i686-unknown-linux-gnu")
45    } else if cfg!(all(target_os = "windows", target_env = "msvc")) {
46        Some("i686-pc-windows-msvc")
47    } else if cfg!(all(target_os = "windows", target_env = "gnu")) {
48        Some("i686-pc-windows-gnu")
49    } else {
50        None
51    }
52}
53
54pub fn alternate_arch() -> &'static str {
55    if cfg!(target_os = "macos") {
56        "x86_64"
57    } else {
58        "x86"
59    }
60}
61
62/// A target-triple that is neither the host nor the target.
63///
64/// Rustc may not work with it and it's alright, apart from being a
65/// valid target triple it is supposed to be used only as a
66/// placeholder for targets that should not be considered.
67pub fn unused() -> &'static str {
68    "wasm32-unknown-unknown"
69}
70
71/// Check if the given target has been installed.
72///
73/// Generally `testsuite::utils::cross_compile::disabled` should be used to check if cross-compilation is allowed.
74/// And [`alternate`] to get the cross target.
75///
76/// You should only use this as a last resort to skip tests,
77/// because it doesn't report skipped tests as ignored.
78pub fn requires_target_installed(target: &str) -> bool {
79    let has_target = std::process::Command::new("rustup")
80        .args(["target", "list", "--installed"])
81        .output()
82        .ok()
83        .map(|output| {
84            String::from_utf8(output.stdout)
85                .map(|stdout| stdout.contains(target))
86                .unwrap_or_default()
87        })
88        .unwrap_or_default();
89    if !has_target {
90        let msg =
91            format!("to run this test, run `rustup target add {target} --toolchain <toolchain>`",);
92        if cargo_util::is_ci() {
93            panic!("{msg}");
94        } else {
95            eprintln!("{msg}");
96        }
97    }
98    has_target
99}
cargo_test_support/cross_compile.rs

cargo_test_support/
cross_compile.rs
