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Diffstat (limited to 'build.rs')
| -rw-r--r-- | build.rs | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/build.rs b/build.rs new file mode 100644 index 0000000..ccbddd2 --- /dev/null +++ b/build.rs @@ -0,0 +1,146 @@ +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() { + println!("cargo:rerun-if-changed=build.rs"); + + 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<Box<T>> for Rc<T> / Arc<T> stabilized in Rust 1.21: + // https://doc.rust-lang.org/std/rc/struct.Rc.html#impl-From<Box<T>> + // https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-From<Box<T>> + 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"); + println!("cargo:rustc-cfg=no_relaxed_trait_bounds"); + } + + // Support for #[cfg(target_has_atomic = "...")] stabilized in Rust 1.60. + if minor < 60 { + println!("cargo:rustc-cfg=no_target_has_atomic"); + // Allowlist of archs that support std::sync::atomic module. 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<u32> { + 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() +} |