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use std::env;
use std::process::Command;
use std::str;
// List of cfgs this build script is allowed to set. The list is needed to support check-cfg, as we
// need to know all the possible cfgs that this script will set. If you need to set another cfg
// make sure to add it to this list as well.
const ALLOWED_CFGS: &'static [&'static str] = &[
"emscripten_new_stat_abi",
"espidf_time64",
"freebsd10",
"freebsd11",
"freebsd12",
"freebsd13",
"freebsd14",
"freebsd15",
"libc_align",
"libc_cfg_target_vendor",
"libc_const_extern_fn",
"libc_const_extern_fn_unstable",
"libc_const_size_of",
"libc_core_cvoid",
"libc_deny_warnings",
"libc_int128",
"libc_long_array",
"libc_non_exhaustive",
"libc_packedN",
"libc_priv_mod_use",
"libc_ptr_addr_of",
"libc_thread_local",
"libc_underscore_const_names",
"libc_union",
];
// Extra values to allow for check-cfg.
const CHECK_CFG_EXTRA: &'static [(&'static str, &'static [&'static str])] = &[
("target_os", &["switch", "aix", "ohos", "hurd", "visionos"]),
("target_env", &["illumos", "wasi", "aix", "ohos"]),
(
"target_arch",
&["loongarch64", "mips32r6", "mips64r6", "csky"],
),
];
fn main() {
// Avoid unnecessary re-building.
println!("cargo:rerun-if-changed=build.rs");
let (rustc_minor_ver, is_nightly) = rustc_minor_nightly();
let rustc_dep_of_std = env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
let align_cargo_feature = env::var("CARGO_FEATURE_ALIGN").is_ok();
let const_extern_fn_cargo_feature = env::var("CARGO_FEATURE_CONST_EXTERN_FN").is_ok();
let libc_ci = env::var("LIBC_CI").is_ok();
let libc_check_cfg = env::var("LIBC_CHECK_CFG").is_ok() || rustc_minor_ver >= 80;
if env::var("CARGO_FEATURE_USE_STD").is_ok() {
println!(
"cargo:warning=\"libc's use_std cargo feature is deprecated since libc 0.2.55; \
please consider using the `std` cargo feature instead\""
);
}
// The ABI of libc used by std is backward compatible with FreeBSD 12.
// The ABI of libc from crates.io is backward compatible with FreeBSD 11.
//
// On CI, we detect the actual FreeBSD version and match its ABI exactly,
// running tests to ensure that the ABI is correct.
let which_freebsd = if libc_ci {
which_freebsd().unwrap_or(11)
} else if rustc_dep_of_std {
12
} else {
11
};
match which_freebsd {
x if x < 10 => panic!("FreeBSD older than 10 is not supported"),
10 => set_cfg("freebsd10"),
11 => set_cfg("freebsd11"),
12 => set_cfg("freebsd12"),
13 => set_cfg("freebsd13"),
14 => set_cfg("freebsd14"),
_ => set_cfg("freebsd15"),
}
match emcc_version_code() {
Some(v) if (v >= 30142) => set_cfg("emscripten_new_stat_abi"),
// Non-Emscripten or version < 3.1.42.
Some(_) | None => (),
}
// On CI: deny all warnings
if libc_ci {
set_cfg("libc_deny_warnings");
}
// Rust >= 1.15 supports private module use:
if rustc_minor_ver >= 15 || rustc_dep_of_std {
set_cfg("libc_priv_mod_use");
}
// Rust >= 1.19 supports unions:
if rustc_minor_ver >= 19 || rustc_dep_of_std {
set_cfg("libc_union");
}
// Rust >= 1.24 supports const mem::size_of:
if rustc_minor_ver >= 24 || rustc_dep_of_std {
set_cfg("libc_const_size_of");
}
// Rust >= 1.25 supports repr(align):
if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature {
set_cfg("libc_align");
}
// Rust >= 1.26 supports i128 and u128:
if rustc_minor_ver >= 26 || rustc_dep_of_std {
set_cfg("libc_int128");
}
// Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it.
// Otherwise, it defines an incompatible type to retaining
// backwards-compatibility.
if rustc_minor_ver >= 30 || rustc_dep_of_std {
set_cfg("libc_core_cvoid");
}
// Rust >= 1.33 supports repr(packed(N)) and cfg(target_vendor).
if rustc_minor_ver >= 33 || rustc_dep_of_std {
set_cfg("libc_packedN");
set_cfg("libc_cfg_target_vendor");
}
// Rust >= 1.40 supports #[non_exhaustive].
if rustc_minor_ver >= 40 || rustc_dep_of_std {
set_cfg("libc_non_exhaustive");
}
// Rust >= 1.47 supports long array:
if rustc_minor_ver >= 47 || rustc_dep_of_std {
set_cfg("libc_long_array");
}
if rustc_minor_ver >= 51 || rustc_dep_of_std {
set_cfg("libc_ptr_addr_of");
}
// Rust >= 1.37.0 allows underscores as anonymous constant names.
if rustc_minor_ver >= 37 || rustc_dep_of_std {
set_cfg("libc_underscore_const_names");
}
// #[thread_local] is currently unstable
if rustc_dep_of_std {
set_cfg("libc_thread_local");
}
// Rust >= 1.62.0 allows to use `const_extern_fn` for "Rust" and "C".
if rustc_minor_ver >= 62 {
set_cfg("libc_const_extern_fn");
} else {
// Rust < 1.62.0 requires a crate feature and feature gate.
if const_extern_fn_cargo_feature {
if !is_nightly || rustc_minor_ver < 40 {
panic!("const-extern-fn requires a nightly compiler >= 1.40");
}
set_cfg("libc_const_extern_fn_unstable");
set_cfg("libc_const_extern_fn");
}
}
// check-cfg is a nightly cargo/rustc feature to warn when unknown cfgs are used across the
// codebase. libc can configure it if the appropriate environment variable is passed. Since
// rust-lang/rust enforces it, this is useful when using a custom libc fork there.
//
if libc_check_cfg {
for cfg in ALLOWED_CFGS {
if rustc_minor_ver >= 75 {
println!("cargo:rustc-check-cfg=cfg({})", cfg);
} else {
println!("cargo:rustc-check-cfg=values({})", cfg);
}
}
for &(name, values) in CHECK_CFG_EXTRA {
let values = values.join("\",\"");
if rustc_minor_ver >= 75 {
println!("cargo:rustc-check-cfg=cfg({},values(\"{}\"))", name, values);
} else {
println!("cargo:rustc-check-cfg=values({},\"{}\")", name, values);
}
}
}
}
fn rustc_minor_nightly() -> (u32, bool) {
macro_rules! otry {
($e:expr) => {
match $e {
Some(e) => e,
None => panic!("Failed to get rustc version"),
}
};
}
let rustc = env::var_os("RUSTC").expect("Failed to get rustc version: missing RUSTC env");
let mut cmd = match env::var_os("RUSTC_WRAPPER").as_ref() {
Some(wrapper) if !wrapper.is_empty() => {
let mut cmd = Command::new(wrapper);
cmd.arg(rustc);
cmd
}
_ => Command::new(rustc),
};
let output = cmd
.arg("--version")
.output()
.ok()
.expect("Failed to get rustc version");
if !output.status.success() {
panic!(
"failed to run rustc: {}",
String::from_utf8_lossy(output.stderr.as_slice())
);
}
let version = otry!(str::from_utf8(&output.stdout).ok());
let mut pieces = version.split('.');
if pieces.next() != Some("rustc 1") {
panic!("Failed to get rustc version");
}
let minor = pieces.next();
// If `rustc` was built from a tarball, its version string
// will have neither a git hash nor a commit date
// (e.g. "rustc 1.39.0"). Treat this case as non-nightly,
// since a nightly build should either come from CI
// or a git checkout
let nightly_raw = otry!(pieces.next()).split('-').nth(1);
let nightly = nightly_raw
.map(|raw| raw.starts_with("dev") || raw.starts_with("nightly"))
.unwrap_or(false);
let minor = otry!(otry!(minor).parse().ok());
(minor, nightly)
}
fn which_freebsd() -> Option<i32> {
let output = std::process::Command::new("freebsd-version").output().ok();
if output.is_none() {
return None;
}
let output = output.unwrap();
if !output.status.success() {
return None;
}
let stdout = String::from_utf8(output.stdout).ok();
if stdout.is_none() {
return None;
}
let stdout = stdout.unwrap();
match &stdout {
s if s.starts_with("10") => Some(10),
s if s.starts_with("11") => Some(11),
s if s.starts_with("12") => Some(12),
s if s.starts_with("13") => Some(13),
s if s.starts_with("14") => Some(14),
s if s.starts_with("15") => Some(15),
_ => None,
}
}
fn emcc_version_code() -> Option<u64> {
let output = std::process::Command::new("emcc")
.arg("-dumpversion")
.output()
.ok();
if output.is_none() {
return None;
}
let output = output.unwrap();
if !output.status.success() {
return None;
}
let stdout = String::from_utf8(output.stdout).ok();
if stdout.is_none() {
return None;
}
let version = stdout.unwrap();
// Some Emscripten versions come with `-git` attached, so split the
// version string also on the `-` char.
let mut pieces = version.trim().split(|c| c == '.' || c == '-');
let major = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
let minor = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
let patch = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
Some(major * 10000 + minor * 100 + patch)
}
fn set_cfg(cfg: &str) {
if !ALLOWED_CFGS.contains(&cfg) {
panic!("trying to set cfg {}, but it is not in ALLOWED_CFGS", cfg);
}
println!("cargo:rustc-cfg={}", cfg);
}