mirror of
https://github.com/saymrwulf/curve25519-dalek-source.git
synced 2026-09-04 20:24:10 +00:00
4583c472f5
* Remove dependency on `packed_simd` * Support SIMD on stable Rust * Move `packed_simd.rs` to `vector` module * Add comment header to `packed_simd.rs` * Initialize SIMD registers using intrinsics instead of `transmute` * Use a splat inside of `unpack_pair` * Update README: the AVX2 backend now works on stable Rust * Add a CI job to also build the AVX2 SIMD backend on Rust stable * Added SIMD MSRV test
87 lines
3.2 KiB
Rust
87 lines
3.2 KiB
Rust
//! This selects the curve25519_dalek_bits either by default from target_pointer_width or explicitly set
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#![deny(clippy::unwrap_used, dead_code)]
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#[allow(non_camel_case_types)]
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enum DalekBits {
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Dalek32,
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Dalek64,
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}
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fn main() {
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let curve25519_dalek_bits = match std::env::var("CARGO_CFG_CURVE25519_DALEK_BITS").as_deref() {
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Ok("32") => DalekBits::Dalek32,
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Ok("64") => DalekBits::Dalek64,
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_ => deterministic::determine_curve25519_dalek_bits(),
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};
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match curve25519_dalek_bits {
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DalekBits::Dalek64 => println!("cargo:rustc-cfg=curve25519_dalek_bits=\"64\""),
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DalekBits::Dalek32 => println!("cargo:rustc-cfg=curve25519_dalek_bits=\"32\""),
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}
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if rustc_version::version_meta()
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.expect("failed to detect rustc version")
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.channel
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== rustc_version::Channel::Nightly
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{
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println!("cargo:rustc-cfg=nightly");
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}
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}
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// Deterministic cfg(curve25519_dalek_bits) when this is not explicitly set.
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mod deterministic {
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use super::*;
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// Standard Cargo TARGET environment variable of triplet is required
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static ERR_MSG_NO_TARGET: &str = "Standard Cargo TARGET environment variable is not set";
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// Custom Non-Rust standard target platforms require explicit settings.
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static ERR_MSG_NO_PLATFORM: &str = "Unknown Rust target platform.";
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// Warning when the curve25519_dalek_bits cannot be determined
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fn determine_curve25519_dalek_bits_warning(cause: &str) {
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println!("cargo:warning=\"Defaulting to curve25519_dalek_bits=32: {cause}\"");
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}
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// Determine the curve25519_dalek_bits based on Rust standard TARGET triplet
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pub(super) fn determine_curve25519_dalek_bits() -> DalekBits {
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use platforms::target::PointerWidth;
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// TARGET environment is supplied by Cargo
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// https://doc.rust-lang.org/cargo/reference/environment-variables.html
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let target_triplet = match std::env::var("TARGET") {
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Ok(t) => t,
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Err(_) => {
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determine_curve25519_dalek_bits_warning(ERR_MSG_NO_TARGET);
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return DalekBits::Dalek32;
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}
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};
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// platforms crate is the source of truth used to determine the platform
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let platform = match platforms::Platform::find(&target_triplet) {
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Some(p) => p,
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None => {
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determine_curve25519_dalek_bits_warning(ERR_MSG_NO_PLATFORM);
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return DalekBits::Dalek32;
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}
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};
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#[allow(clippy::match_single_binding)]
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match platform.target_arch {
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//Issues: 449 and 456
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//TODO(Arm): Needs tests + benchmarks to back this up
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//platforms::target::Arch::Arm => DalekBits::Dalek64,
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//TODO(Wasm32): Needs tests + benchmarks to back this up
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//platforms::target::Arch::Wasm32 => DalekBits::Dalek64,
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_ => match platform.target_pointer_width {
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PointerWidth::U64 => DalekBits::Dalek64,
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PointerWidth::U32 => DalekBits::Dalek32,
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// Intended default solely for non-32/64 target pointer widths
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// Otherwise known target platforms only.
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_ => DalekBits::Dalek32,
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},
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}
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}
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}
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