use std::env; use std::process::Command; use std::str::{self, FromStr}; // The rustc-cfg strings below are *not* public API. Please let us know by // opening a GitHub issue if your build environment requires some way to enable // these cfgs other than by executing our build script. fn main() { let minor = match rustc_minor_version() { Some(minor) => minor, None => return, }; let target = env::var("TARGET").unwrap(); let emscripten = target == "asmjs-unknown-emscripten" || target == "wasm32-unknown-emscripten"; // std::collections::Bound was stabilized in Rust 1.17 // but it was moved to core::ops later in Rust 1.26: // https://doc.rust-lang.org/core/ops/enum.Bound.html if minor < 26 { println!("cargo:rustc-cfg=no_ops_bound"); if minor < 17 { println!("cargo:rustc-cfg=no_collections_bound"); } } // core::cmp::Reverse stabilized in Rust 1.19: // https://doc.rust-lang.org/stable/core/cmp/struct.Reverse.html if minor < 19 { println!("cargo:rustc-cfg=no_core_reverse"); } // CString::into_boxed_c_str and PathBuf::into_boxed_path stabilized in Rust 1.20: // https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str // https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.into_boxed_path if minor < 20 { println!("cargo:rustc-cfg=no_de_boxed_c_str"); println!("cargo:rustc-cfg=no_de_boxed_path"); } // From> for Rc / Arc stabilized in Rust 1.21: // https://doc.rust-lang.org/std/rc/struct.Rc.html#impl-From> // https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-From> if minor < 21 { println!("cargo:rustc-cfg=no_de_rc_dst"); } // Duration available in core since Rust 1.25: // https://blog.rust-lang.org/2018/03/29/Rust-1.25.html#library-stabilizations if minor < 25 { println!("cargo:rustc-cfg=no_core_duration"); } // 128-bit integers stabilized in Rust 1.26: // https://blog.rust-lang.org/2018/05/10/Rust-1.26.html // // Disabled on Emscripten targets before Rust 1.40 since // Emscripten did not support 128-bit integers until Rust 1.40 // (https://github.com/rust-lang/rust/pull/65251) if minor < 26 || emscripten && minor < 40 { println!("cargo:rustc-cfg=no_integer128"); } // Inclusive ranges methods stabilized in Rust 1.27: // https://github.com/rust-lang/rust/pull/50758 // Also Iterator::try_for_each: // https://blog.rust-lang.org/2018/06/21/Rust-1.27.html#library-stabilizations if minor < 27 { println!("cargo:rustc-cfg=no_range_inclusive"); println!("cargo:rustc-cfg=no_iterator_try_fold"); } // Non-zero integers stabilized in Rust 1.28: // https://blog.rust-lang.org/2018/08/02/Rust-1.28.html#library-stabilizations if minor < 28 { println!("cargo:rustc-cfg=no_num_nonzero"); } // Current minimum supported version of serde_derive crate is Rust 1.31. if minor < 31 { println!("cargo:rustc-cfg=no_serde_derive"); } // TryFrom, Atomic types, non-zero signed integers, and SystemTime::checked_add // stabilized in Rust 1.34: // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#library-stabilizations if minor < 34 { println!("cargo:rustc-cfg=no_core_try_from"); println!("cargo:rustc-cfg=no_num_nonzero_signed"); println!("cargo:rustc-cfg=no_systemtime_checked_add"); } // Whitelist of archs that support std::sync::atomic module. Ideally we // would use #[cfg(target_has_atomic = "...")] but it is not stable yet. // Instead this is based on rustc's compiler/rustc_target/src/spec/*.rs. let has_atomic64 = target.starts_with("x86_64") || target.starts_with("i686") || target.starts_with("aarch64") || target.starts_with("powerpc64") || target.starts_with("sparc64") || target.starts_with("mips64el") || target.starts_with("riscv64"); let has_atomic32 = has_atomic64 || emscripten; if minor < 34 || !has_atomic64 { println!("cargo:rustc-cfg=no_std_atomic64"); } if minor < 34 || !has_atomic32 { println!("cargo:rustc-cfg=no_std_atomic"); } } fn rustc_minor_version() -> Option { let rustc = match env::var_os("RUSTC") { Some(rustc) => rustc, None => return None, }; let output = match Command::new(rustc).arg("--version").output() { Ok(output) => output, Err(_) => return None, }; let version = match str::from_utf8(&output.stdout) { Ok(version) => version, Err(_) => return None, }; let mut pieces = version.split('.'); if pieces.next() != Some("rustc 1") { return None; } let next = match pieces.next() { Some(next) => next, None => return None, }; u32::from_str(next).ok() }