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// SPDX-License-Identifier: Apache-2.0 OR MIT
use std::env;
fn main() {
println!("cargo:rerun-if-changed=build.rs");
let target = &*env::var("TARGET").expect("TARGET not set");
let target_arch = &*env::var("CARGO_CFG_TARGET_ARCH").expect("CARGO_CFG_TARGET_ARCH not set");
// HACK: If --target is specified, rustflags is not applied to the build
// script itself, so the build script will not be rerun when these are changed.
//
// Ideally, the build script should be rebuilt when CARGO_ENCODED_RUSTFLAGS
// is changed, but since it is an environment variable set by cargo,
// as of 1.62.0-nightly, specifying it as rerun-if-env-changed does not work.
println!("cargo:rerun-if-env-changed=CARGO_ENCODED_RUSTFLAGS");
println!("cargo:rerun-if-env-changed=RUSTFLAGS");
println!("cargo:rerun-if-env-changed=CARGO_BUILD_RUSTFLAGS");
let mut target_upper = target.replace(['-', '.'], "_");
target_upper.make_ascii_uppercase();
println!("cargo:rerun-if-env-changed=CARGO_TARGET_{target_upper}_RUSTFLAGS");
let version = match rustc_version() {
Some(version) => version,
None => {
println!(
"cargo:warning={}: unable to determine rustc version; assuming latest stable rustc (1.{})",
env!("CARGO_PKG_NAME"),
Version::LATEST.minor
);
Version::LATEST
}
};
if version.nightly && is_allowed_feature("rustc_attrs") {
println!("cargo:rustc-cfg=semihosting_unstable_rustc_attrs");
}
if target_arch == "arm" {
if target.starts_with("thumb") {
target_feature_if("thumb-mode", true, &version, None, true)
}
// See portable-atomic's build.rs for more
let mut subarch =
target.strip_prefix("arm").or_else(|| target.strip_prefix("thumb")).unwrap();
subarch = subarch.strip_prefix("eb").unwrap_or(subarch); // ignore endianness
subarch = subarch.split('-').next().unwrap(); // ignore vender/os/env
subarch = subarch.split('.').next().unwrap(); // ignore .base/.main suffix
let mut known = true;
// See https://github.com/taiki-e/atomic-maybe-uninit/blob/HEAD/build.rs for details
let mut is_mclass = false;
match subarch {
"v7" | "v7a" | "v7neon" | "v7s" | "v7k" | "v8a" => {} // aclass
"v6m" | "v7em" | "v7m" | "v8m" => is_mclass = true,
"v7r" | "v8r" => {} // rclass
// arm-linux-androideabi is v5te
// https://github.com/rust-lang/rust/blob/1.69.0/compiler/rustc_target/src/spec/arm_linux_androideabi.rs#L11-L12
_ if target == "arm-linux-androideabi" => subarch = "v5te",
// v6 targets other than v6m don't have *class target feature.
"" | "v6" | "v6k" => subarch = "v6",
// Other targets don't have *class target feature.
"v4t" | "v5te" => {}
_ => {
known = false;
println!(
"cargo:warning={}: unrecognized arm subarch: {}",
env!("CARGO_PKG_NAME"),
target
);
}
}
let (v8, v8m) = if known && subarch.starts_with("v8") {
// ARMv8-M Mainline/Baseline are not considered as v8 by rustc.
// https://github.com/rust-lang/stdarch/blob/a0c30f3e3c75adcd6ee7efc94014ebcead61c507/crates/core_arch/src/arm_shared/mod.rs
if subarch.starts_with("v8m") {
(false, true)
} else {
(true, false)
}
} else {
(false, false)
};
target_feature_if("mclass", is_mclass, &version, None, true);
target_feature_if("v8", v8, &version, None, true);
target_feature_if("v8m", v8m, &version, None, false);
}
}
fn target_feature_if(
name: &str,
mut has_target_feature: bool,
version: &Version,
stabilized: Option<u32>,
is_rustc_target_feature: bool,
) {
// HACK: Currently, it seems that the only way to handle unstable target
// features on the stable is to parse the `-C target-feature` in RUSTFLAGS.
//
// - #[cfg(target_feature = "unstable_target_feature")] doesn't work on stable.
// - CARGO_CFG_TARGET_FEATURE excludes unstable target features on stable.
//
// As mentioned in the [RFC2045], unstable target features are also passed to LLVM
// (e.g., https://godbolt.org/z/8Eh3z5Wzb), so this hack works properly on stable.
//
// [RFC2045]: https://rust-lang.github.io/rfcs/2045-target-feature.html#backend-compilation-options
if is_rustc_target_feature
&& (version.nightly || stabilized.map_or(false, |stabilized| version.minor >= stabilized))
{
// In this case, cfg(target_feature = "...") would work, so skip emitting our own target_feature cfg.
return;
} else if let Some(rustflags) = env::var_os("CARGO_ENCODED_RUSTFLAGS") {
for mut flag in rustflags.to_string_lossy().split('\x1f') {
flag = flag.strip_prefix("-C").unwrap_or(flag);
if let Some(flag) = flag.strip_prefix("target-feature=") {
for s in flag.split(',') {
// TODO: Handles cases where a specific target feature
// implicitly enables another target feature.
match (s.as_bytes().first(), s.as_bytes().get(1..)) {
(Some(b'+'), Some(f)) if f == name.as_bytes() => has_target_feature = true,
(Some(b'-'), Some(f)) if f == name.as_bytes() => has_target_feature = false,
_ => {}
}
}
}
}
}
if has_target_feature {
println!("cargo:rustc-cfg=semihosting_target_feature=\"{}\"", name);
}
}
fn is_allowed_feature(name: &str) -> bool {
// allowed by default
let mut allowed = true;
if let Some(rustflags) = env::var_os("CARGO_ENCODED_RUSTFLAGS") {
for mut flag in rustflags.to_string_lossy().split('\x1f') {
flag = flag.strip_prefix("-Z").unwrap_or(flag);
if let Some(flag) = flag.strip_prefix("allow-features=") {
// If it is specified multiple times, the last value will be preferred.
allowed = flag.split(',').any(|allowed| allowed == name);
}
}
}
allowed
}
mod version {
use std::{env, process::Command, str};
pub(crate) fn rustc_version() -> Option<Version> {
let rustc = env::var_os("RUSTC")?;
// Use verbose version output because the packagers add extra strings to the normal version output.
let output = Command::new(rustc).args(["--version", "--verbose"]).output().ok()?;
let output = str::from_utf8(&output.stdout).ok()?;
Version::parse(output)
}
#[cfg_attr(test, derive(Debug, PartialEq))]
pub(crate) struct Version {
pub(crate) minor: u32,
pub(crate) nightly: bool,
// commit_date: Date,
}
impl Version {
// The known latest stable version. If we unable to determine
// the rustc version, we assume this is the current version.
// It is no problem if this is older than the actual latest stable.
pub(crate) const LATEST: Self = Self::stable(69);
pub(crate) const fn stable(rustc_minor: u32) -> Self {
Self {
minor: rustc_minor,
nightly: false,
// commit_date: Date::UNKNOWN,
}
}
// pub(crate) fn probe(&self, minor: u32, year: u16, month: u8, day: u8) -> bool {
// if self.nightly {
// self.minor > minor || self.commit_date >= Date::new(year, month, day)
// } else {
// self.minor >= minor
// }
// }
pub(crate) fn parse(text: &str) -> Option<Self> {
let mut release = text
.lines()
.find(|line| line.starts_with("release: "))
.map(|line| &line["release: ".len()..])?
.splitn(2, '-');
let version = release.next().unwrap();
let channel = release.next().unwrap_or_default();
let mut digits = version.splitn(3, '.');
let major = digits.next()?.parse::<u32>().ok()?;
if major != 1 {
return None;
}
let minor = digits.next()?.parse::<u32>().ok()?;
let _patch = digits.next().unwrap_or("0").parse::<u32>().ok()?;
let nightly = channel == "nightly" || channel == "dev";
// we don't refer commit date on stable/beta.
if nightly {
// let commit_date = (|| {
// let mut commit_date = text
// .lines()
// .find(|line| line.starts_with("commit-date: "))
// .map(|line| &line["commit-date: ".len()..])?
// .splitn(3, '-');
// let year = commit_date.next()?.parse::<u16>().ok()?;
// let month = commit_date.next()?.parse::<u8>().ok()?;
// let day = commit_date.next()?.parse::<u8>().ok()?;
// if month > 12 || day > 31 {
// return None;
// }
// Some(Date::new(year, month, day))
// })();
Some(Version {
minor,
nightly,
// commit_date: commit_date.unwrap_or(Date::UNKNOWN),
})
} else {
Some(Version::stable(minor))
}
}
}
// #[derive(PartialEq, PartialOrd)]
// pub(crate) struct Date {
// pub(crate) year: u16,
// pub(crate) month: u8,
// pub(crate) day: u8,
// }
// impl Date {
// const UNKNOWN: Self = Self::new(0, 0, 0);
// const fn new(year: u16, month: u8, day: u8) -> Self {
// Self { year, month, day }
// }
// }
}
use version::{rustc_version, Version};