| // The rustc-cfg emitted by the build script are *not* public API. |
| |
| #![warn(rust_2018_idioms, single_use_lifetimes)] |
| |
| #[path = "version.rs"] |
| mod version; |
| use version::{rustc_version, Version}; |
| |
| use std::{env, str}; |
| |
| include!("no_atomic.rs"); |
| |
| fn main() { |
| println!("cargo:rerun-if-changed=build.rs"); |
| println!("cargo:rerun-if-changed=no_atomic.rs"); |
| println!("cargo:rerun-if-changed=version.rs"); |
| |
| #[cfg(feature = "unsafe-assume-single-core")] |
| println!("cargo:rustc-cfg=portable_atomic_unsafe_assume_single_core"); |
| #[cfg(feature = "s-mode")] |
| println!("cargo:rustc-cfg=portable_atomic_s_mode"); |
| #[cfg(feature = "disable-fiq")] |
| println!("cargo:rustc-cfg=portable_atomic_disable_fiq"); |
| |
| 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"); |
| let target_os = &*env::var("CARGO_CFG_TARGET_OS").expect("CARGO_CFG_TARGET_OS 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(|c: char| c == '-' || c == '.', "_"); |
| target_upper.make_ascii_uppercase(); |
| println!("cargo:rerun-if-env-changed=CARGO_TARGET_{}_RUSTFLAGS", target_upper); |
| |
| 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 |
| } |
| }; |
| |
| // Note that this is `no_`*, not `has_*`. This allows treating as the latest |
| // stable rustc is used when the build script doesn't run. This is useful |
| // for non-cargo build systems that don't run the build script. |
| // atomic_min_max stabilized in Rust 1.45 (nightly-2020-05-30): https://github.com/rust-lang/rust/pull/72324 |
| if !version.probe(45, 2020, 5, 29) { |
| println!("cargo:rustc-cfg=portable_atomic_no_atomic_min_max"); |
| } |
| // track_caller stabilized in Rust 1.46 (nightly-2020-07-02): https://github.com/rust-lang/rust/pull/72445 |
| if !version.probe(46, 2020, 7, 1) { |
| println!("cargo:rustc-cfg=portable_atomic_no_track_caller"); |
| } |
| // unsafe_op_in_unsafe_fn stabilized in Rust 1.52 (nightly-2021-03-11): https://github.com/rust-lang/rust/pull/79208 |
| if !version.probe(52, 2021, 3, 10) { |
| println!("cargo:rustc-cfg=portable_atomic_no_unsafe_op_in_unsafe_fn"); |
| } |
| // https://github.com/rust-lang/rust/pull/84662 merged in Rust 1.56 (nightly-2021-08-02). |
| if !version.probe(56, 2021, 8, 1) { |
| println!("cargo:rustc-cfg=portable_atomic_no_core_unwind_safe"); |
| } |
| // const_raw_ptr_deref stabilized in Rust 1.58 (nightly-2021-11-15): https://github.com/rust-lang/rust/pull/89551 |
| if !version.probe(58, 2021, 11, 14) { |
| println!("cargo:rustc-cfg=portable_atomic_no_const_raw_ptr_deref"); |
| } |
| // https://github.com/rust-lang/rust/pull/98383 merged in Rust 1.64 (nightly-2022-07-19). |
| if !version.probe(64, 2022, 7, 18) { |
| println!("cargo:rustc-cfg=portable_atomic_no_stronger_failure_ordering"); |
| } |
| |
| // asm stabilized in Rust 1.59 (nightly-2021-12-16): https://github.com/rust-lang/rust/pull/91728 |
| let no_asm = !version.probe(59, 2021, 12, 15); |
| if no_asm { |
| if version.nightly |
| && version.probe(46, 2020, 6, 20) |
| && ((target_arch != "x86" && target_arch != "x86_64") || version.llvm >= 10) |
| && is_allowed_feature("asm") |
| { |
| // This feature was added in Rust 1.45 (nightly-2020-05-20), but |
| // concat! in asm! requires Rust 1.46 (nightly-2020-06-21). |
| // x86 intel syntax requires LLVM 10 (since Rust 1.53, the minimum |
| // external LLVM version is 10+: https://github.com/rust-lang/rust/pull/83387). |
| // The part of this feature we use has not been changed since nightly-2020-06-21 |
| // until it was stabilized in nightly-2021-12-16, so it can be safely enabled in |
| // nightly, which is older than nightly-2021-12-16. |
| println!("cargo:rustc-cfg=portable_atomic_unstable_asm"); |
| } |
| println!("cargo:rustc-cfg=portable_atomic_no_asm"); |
| } |
| |
| // feature(cfg_target_has_atomic) stabilized in Rust 1.60 (nightly-2022-02-11): https://github.com/rust-lang/rust/pull/93824 |
| if !version.probe(60, 2022, 2, 10) { |
| if version.nightly |
| && version.probe(40, 2019, 10, 13) |
| && is_allowed_feature("cfg_target_has_atomic") |
| { |
| // This feature has not been changed since the change in Rust 1.40 (nightly-2019-10-14) |
| // until it was stabilized in nightly-2022-02-11, so it can be safely enabled in |
| // nightly, which is older than nightly-2022-02-11. |
| println!("cargo:rustc-cfg=portable_atomic_unstable_cfg_target_has_atomic"); |
| } else { |
| println!("cargo:rustc-cfg=portable_atomic_no_cfg_target_has_atomic"); |
| let target = &*convert_custom_linux_target(target); |
| if NO_ATOMIC_CAS.contains(&target) { |
| println!("cargo:rustc-cfg=portable_atomic_no_atomic_cas"); |
| } |
| if NO_ATOMIC_64.contains(&target) { |
| println!("cargo:rustc-cfg=portable_atomic_no_atomic_64"); |
| } else { |
| // Otherwise, assuming `"max-atomic-width" == 64` or `"max-atomic-width" == 128`. |
| } |
| } |
| } |
| // We don't need to use convert_custom_linux_target here because all linux targets have atomics. |
| if NO_ATOMIC.contains(&target) { |
| println!("cargo:rustc-cfg=portable_atomic_no_atomic_load_store"); |
| } |
| |
| if version.llvm >= 16 { |
| println!("cargo:rustc-cfg=portable_atomic_llvm_16"); |
| } |
| if version.nightly { |
| // https://github.com/rust-lang/rust/pull/97423 merged in Rust 1.64 (nightly-2022-06-30). |
| if version.probe(64, 2022, 6, 29) { |
| println!("cargo:rustc-cfg=portable_atomic_new_atomic_intrinsics"); |
| } |
| // https://github.com/rust-lang/rust/pull/100911 (includes https://github.com/rust-lang/stdarch/pull/1315) merged in Rust 1.65 (nightly-2022-08-26). |
| if target_arch == "x86_64" && !version.probe(65, 2022, 8, 25) { |
| println!( |
| "cargo:rustc-cfg=portable_atomic_no_cmpxchg16b_intrinsic_stronger_failure_ordering" |
| ); |
| } |
| // feature(isa_attribute) stabilized in Rust 1.67 (nightly-2022-11-06): https://github.com/rust-lang/rust/pull/102458 |
| if target_arch == "arm" && !version.probe(67, 2022, 11, 5) { |
| println!("cargo:rustc-cfg=portable_atomic_unstable_isa_attribute"); |
| } |
| |
| // `cfg(sanitize = "..")` is not stabilized. |
| let sanitize = env::var("CARGO_CFG_SANITIZE").unwrap_or_default(); |
| if sanitize.contains("thread") { |
| // Most kinds of sanitizers are not compatible with asm |
| // (https://github.com/google/sanitizers/issues/192), |
| // but it seems that ThreadSanitizer is the only one that can cause |
| // false positives in our code. |
| println!("cargo:rustc-cfg=portable_atomic_sanitize_thread"); |
| } |
| |
| if version.llvm >= 15 { |
| println!("cargo:rustc-cfg=portable_atomic_llvm_15"); |
| } |
| // https://github.com/rust-lang/rust/pull/93868 merged in Rust 1.60 (nightly-2022-02-13). |
| // https://github.com/rust-lang/rust/pull/111331 merged in Rust 1.71 (nightly-2023-05-09). |
| if !no_asm |
| && (target_arch == "powerpc64" && version.probe(60, 2022, 2, 12) |
| || target_arch == "s390x" && version.probe(71, 2023, 5, 8)) |
| && is_allowed_feature("asm_experimental_arch") |
| { |
| println!("cargo:rustc-cfg=portable_atomic_unstable_asm_experimental_arch"); |
| } |
| } |
| |
| let is_apple = |
| target_os == "macos" || target_os == "ios" || target_os == "tvos" || target_os == "watchos"; |
| match target_arch { |
| "x86_64" => { |
| // cmpxchg16b_target_feature stabilized in Rust 1.69 (nightly-2023-03-01): https://github.com/rust-lang/rust/pull/106774 |
| if !version.probe(69, 2023, 2, 28) { |
| if version.nightly && is_allowed_feature("cmpxchg16b_target_feature") { |
| // This feature has not been changed since 1.33 |
| // (https://github.com/rust-lang/rust/commit/fbb56bcf44d28e65a9495decf091b6d0386e540c) |
| // until it was stabilized in nightly-2023-03-01, so it can be safely enabled in |
| // nightly, which is older than nightly-2023-03-01. |
| println!("cargo:rustc-cfg=portable_atomic_unstable_cmpxchg16b_target_feature"); |
| } else { |
| println!("cargo:rustc-cfg=portable_atomic_no_cmpxchg16b_target_feature"); |
| } |
| } |
| |
| // x86_64 Apple targets always support CMPXCHG16B: |
| // https://github.com/rust-lang/rust/blob/1.70.0/compiler/rustc_target/src/spec/x86_64_apple_darwin.rs#L8 |
| // https://github.com/rust-lang/rust/blob/1.70.0/compiler/rustc_target/src/spec/apple_base.rs#L69-L70 |
| // Script to get targets that support cmpxchg16b by default: |
| // $ (for target in $(rustc --print target-list); do [[ "${target}" == "x86_64"* ]] && rustc --print cfg --target "${target}" | grep -q cmpxchg16b && echo "${target}"; done) |
| let has_cmpxchg16b = is_apple; |
| // LLVM recognizes this also as cx16 target feature: https://godbolt.org/z/6dszGeYsf |
| // It is unlikely that rustc will support that name, so we ignore it. |
| // cmpxchg16b_target_feature stabilized in Rust 1.69. |
| target_feature_if("cmpxchg16b", has_cmpxchg16b, &version, Some(69), true); |
| } |
| "aarch64" => { |
| // aarch64_target_feature stabilized in Rust 1.61 (nightly-2022-03-16): https://github.com/rust-lang/rust/pull/90621 |
| if !version.probe(61, 2022, 3, 15) { |
| if version.nightly && is_allowed_feature("aarch64_target_feature") { |
| // The part of this feature we use has not been changed since 1.27 |
| // (https://github.com/rust-lang/rust/commit/1217d70465edb2079880347fea4baaac56895f51) |
| // until it was stabilized in nightly-2022-03-16, so it can be safely enabled in |
| // nightly, which is older than nightly-2022-03-16. |
| println!("cargo:rustc-cfg=portable_atomic_unstable_aarch64_target_feature"); |
| } else { |
| // On aarch64, when aarch64_target_feature is not available, outline-atomics is also not available. |
| println!("cargo:rustc-cfg=portable_atomic_no_outline_atomics"); |
| } |
| } |
| |
| // aarch64 macOS always support FEAT_LSE and FEAT_LSE2 because it is armv8.5-a: |
| // https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0/llvm/include/llvm/TargetParser/AArch64TargetParser.h#L458 |
| let is_macos = target_os == "macos"; |
| // aarch64_target_feature stabilized in Rust 1.61. |
| target_feature_if("lse", is_macos, &version, Some(61), true); |
| // As of rustc 1.70, target_feature "lse2" is not available on rustc side: |
| // https://github.com/rust-lang/rust/blob/1.70.0/compiler/rustc_codegen_ssa/src/target_features.rs#L58 |
| target_feature_if("lse2", is_macos, &version, None, false); |
| |
| // As of Apple M1/M1 Pro, on Apple hardware, CAS loop-based RMW is much slower than LL/SC |
| // loop-based RMW: https://github.com/taiki-e/portable-atomic/pull/89 |
| if is_apple { |
| println!("cargo:rustc-cfg=portable_atomic_ll_sc_rmw"); |
| } |
| } |
| "arm" => { |
| // #[cfg(target_feature = "v7")] and others don't work on stable. |
| // armv7-unknown-linux-gnueabihf |
| // ^^ |
| let mut subarch = |
| strip_prefix(target, "arm").or_else(|| strip_prefix(target, "thumb")).unwrap(); |
| subarch = strip_prefix(subarch, "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" | "v9a" => {} // aclass |
| "v6m" | "v7em" | "v7m" | "v8m" => is_mclass = true, |
| "v7r" | "v8r" => {} // rclass |
| // arm-linux-androideabi is v5te |
| // https://github.com/rust-lang/rust/blob/1.70.0/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 |
| ); |
| } |
| } |
| target_feature_if("mclass", is_mclass, &version, None, true); |
| let v6 = known |
| && (subarch.starts_with("v6") |
| || subarch.starts_with("v7") |
| || subarch.starts_with("v8") |
| || subarch.starts_with("v9")); |
| target_feature_if("v6", v6, &version, None, true); |
| } |
| "powerpc64" => { |
| let target_endian = |
| env::var("CARGO_CFG_TARGET_ENDIAN").expect("CARGO_CFG_TARGET_ENDIAN not set"); |
| // powerpc64le is pwr8+ by default https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0/llvm/lib/Target/PowerPC/PPC.td#L663 |
| // See also https://github.com/rust-lang/rust/issues/59932 |
| let mut has_pwr8_features = target_endian == "little"; |
| // https://github.com/llvm/llvm-project/commit/549e118e93c666914a1045fde38a2cac33e1e445 |
| if let Some(cpu) = target_cpu().as_ref() { |
| if let Some(mut cpu_version) = strip_prefix(cpu, "pwr") { |
| cpu_version = strip_suffix(cpu_version, "x").unwrap_or(cpu_version); // for pwr5x and pwr6x |
| if let Ok(cpu_version) = cpu_version.parse::<u32>() { |
| has_pwr8_features = cpu_version >= 8; |
| } |
| } else { |
| // https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0/llvm/lib/Target/PowerPC/PPC.td#L663 |
| // https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0/llvm/lib/Target/PowerPC/PPC.td#L445-L447 |
| has_pwr8_features = cpu == "ppc64le" || cpu == "future"; |
| } |
| } |
| // Note: As of rustc 1.70, target_feature "quadword-atomics" is not available on rustc side: |
| // https://github.com/rust-lang/rust/blob/1.70.0/compiler/rustc_codegen_ssa/src/target_features.rs#L226 |
| // lqarx and stqcx. |
| target_feature_if("quadword-atomics", has_pwr8_features, &version, None, false); |
| } |
| "s390x" => { |
| // https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0/llvm/lib/Target/SystemZ/SystemZFeatures.td#L37 |
| let mut has_arch9_features = false; // z196+ |
| let mut has_arch13_features = false; // z15+ |
| if let Some(cpu) = target_cpu() { |
| // https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0/llvm/lib/Target/SystemZ/SystemZProcessors.td |
| match &*cpu { |
| "arch9" | "z196" | "arch10" | "zEC12" | "arch11" | "z13" | "arch12" | "z14" => { |
| has_arch9_features = true; |
| } |
| "arch13" | "z15" | "arch14" | "z16" => { |
| has_arch9_features = true; |
| has_arch13_features = true; |
| } |
| _ => {} |
| } |
| } |
| // Note: As of rustc 1.70, target_feature "fast-serialization"/"load-store-on-cond"/"distinct-ops"/"miscellaneous-extensions-3" is not available on rustc side: |
| // https://github.com/rust-lang/rust/blob/1.70.0/compiler/rustc_codegen_ssa/src/target_features.rs |
| // bcr 14,0 |
| target_feature_if("fast-serialization", has_arch9_features, &version, None, false); |
| // {l,st}oc{,g}{,r} |
| target_feature_if("load-store-on-cond", has_arch9_features, &version, None, false); |
| // {al,sl,n,o,x}{,g}rk |
| target_feature_if("distinct-ops", has_arch9_features, &version, None, false); |
| // nand (nnr{,g}k), select (sel{,g}r), etc. |
| target_feature_if( |
| "miscellaneous-extensions-3", |
| has_arch13_features, |
| &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 = strip_prefix(flag, "-C").unwrap_or(flag); |
| if let Some(flag) = strip_prefix(flag, "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=portable_atomic_target_feature=\"{}\"", name); |
| } |
| } |
| |
| fn target_cpu() -> Option<String> { |
| let rustflags = env::var_os("CARGO_ENCODED_RUSTFLAGS")?; |
| let rustflags = rustflags.to_string_lossy(); |
| let mut cpu = None; |
| for mut flag in rustflags.split('\x1f') { |
| flag = strip_prefix(flag, "-C").unwrap_or(flag); |
| if let Some(flag) = strip_prefix(flag, "target-cpu=") { |
| cpu = Some(flag); |
| } |
| } |
| cpu.map(str::to_owned) |
| } |
| |
| 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 = strip_prefix(flag, "-Z").unwrap_or(flag); |
| if let Some(flag) = strip_prefix(flag, "allow-features=") { |
| // If it is specified multiple times, the last value will be preferred. |
| allowed = flag.split(',').any(|allowed| allowed == name); |
| } |
| } |
| } |
| allowed |
| } |
| |
| // Adapted from https://github.com/crossbeam-rs/crossbeam/blob/crossbeam-utils-0.8.14/build-common.rs. |
| // |
| // The target triplets have the form of 'arch-vendor-system'. |
| // |
| // When building for Linux (e.g. the 'system' part is |
| // 'linux-something'), replace the vendor with 'unknown' |
| // so that mapping to rust standard targets happens correctly. |
| fn convert_custom_linux_target(target: &str) -> String { |
| let mut parts: Vec<&str> = target.split('-').collect(); |
| let system = parts.get(2); |
| if system == Some(&"linux") { |
| parts[1] = "unknown"; |
| } |
| parts.join("-") |
| } |
| |
| // str::strip_prefix requires Rust 1.45 |
| #[must_use] |
| fn strip_prefix<'a>(s: &'a str, pat: &str) -> Option<&'a str> { |
| if s.starts_with(pat) { |
| Some(&s[pat.len()..]) |
| } else { |
| None |
| } |
| } |
| // str::strip_suffix requires Rust 1.45 |
| #[must_use] |
| fn strip_suffix<'a>(s: &'a str, pat: &str) -> Option<&'a str> { |
| if s.ends_with(pat) { |
| Some(&s[..s.len() - pat.len()]) |
| } else { |
| None |
| } |
| } |
