| use std::env; |
| use std::ffi::OsString; |
| use std::process::Command; |
| |
| fn main() { |
| let rustc = env::var_os("RUSTC").unwrap_or(OsString::from("rustc")); |
| let output = Command::new(&rustc) |
| .arg("--version") |
| .output() |
| .unwrap() |
| .stdout; |
| let version = String::from_utf8(output).unwrap(); |
| |
| enable_simd_optimizations(&version); |
| } |
| |
| fn enable_simd_optimizations(version: &str) { |
| // We don't activate SIMD optimizations these if we've explicitly disabled |
| // them. Disabling auto optimizations is intended for use in tests, so that |
| // we can reliably test fallback implementations. |
| if env::var_os("CARGO_CFG_REGEX_DISABLE_AUTO_OPTIMIZATIONS").is_some() { |
| return; |
| } |
| let parsed = match Version::parse(&version) { |
| Ok(parsed) => parsed, |
| Err(err) => { |
| eprintln!("failed to parse `rustc --version`: {}", err); |
| return; |
| } |
| }; |
| let minimum = Version { major: 1, minor: 27, patch: 0 }; |
| if version.contains("nightly") || parsed >= minimum { |
| println!("cargo:rustc-cfg=regex_runtime_teddy_ssse3"); |
| println!("cargo:rustc-cfg=regex_runtime_teddy_avx2"); |
| } |
| } |
| |
| #[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord)] |
| struct Version { |
| major: u32, |
| minor: u32, |
| patch: u32, |
| } |
| |
| impl Version { |
| fn parse(mut s: &str) -> Result<Version, String> { |
| if !s.starts_with("rustc ") { |
| return Err(format!("unrecognized version string: {}", s)); |
| } |
| s = &s["rustc ".len()..]; |
| |
| let parts: Vec<&str> = s.split(".").collect(); |
| if parts.len() < 3 { |
| return Err(format!("not enough version parts: {:?}", parts)); |
| } |
| |
| let mut num = String::new(); |
| for c in parts[0].chars() { |
| if !c.is_digit(10) { |
| break; |
| } |
| num.push(c); |
| } |
| let major = num.parse::<u32>().map_err(|e| e.to_string())?; |
| |
| num.clear(); |
| for c in parts[1].chars() { |
| if !c.is_digit(10) { |
| break; |
| } |
| num.push(c); |
| } |
| let minor = num.parse::<u32>().map_err(|e| e.to_string())?; |
| |
| num.clear(); |
| for c in parts[2].chars() { |
| if !c.is_digit(10) { |
| break; |
| } |
| num.push(c); |
| } |
| let patch = num.parse::<u32>().map_err(|e| e.to_string())?; |
| |
| Ok(Version { major, minor, patch }) |
| } |
| } |