49 lines
1.3 KiB
Rust
49 lines
1.3 KiB
Rust
use std::env;
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use std::io::Write;
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use std::process::{Command, Stdio};
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fn main() {
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if probe("fn main() { 0i128; }") {
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println!("cargo:rustc-cfg=has_i128");
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} else if env::var_os("CARGO_FEATURE_I128").is_some() {
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panic!("i128 support was not detected!");
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}
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if probe(r#"
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fn main() {
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let bytes = 0x1234567890123456u64.to_ne_bytes();
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assert_eq!(bytes, if cfg!(target_endian = "big") {
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[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]
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} else {
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[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
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});
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}"#) {
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println!("cargo:rustc-cfg=int_to_from_bytes");
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}
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}
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/// Test if a code snippet can be compiled
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fn probe(code: &str) -> bool {
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let rustc = env::var_os("RUSTC").unwrap_or_else(|| "rustc".into());
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let out_dir = env::var_os("OUT_DIR").expect("environment variable OUT_DIR");
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let mut child = Command::new(rustc)
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.arg("--out-dir")
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.arg(out_dir)
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.arg("--emit=obj")
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.arg("-")
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.stdin(Stdio::piped())
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.spawn()
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.expect("rustc probe");
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child
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.stdin
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.as_mut()
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.expect("rustc stdin")
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.write_all(code.as_bytes())
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.expect("write rustc stdin");
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child.wait().expect("rustc probe").success()
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}
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