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use std::env;
fn defined(var: &str) -> bool {
env::var_os(var).is_some()
}
fn target_components() -> Vec<String> {
let target = env::var("TARGET").unwrap();
target.split("-").map(|s| s.to_string()).collect()
}
fn is_x86_64() -> bool {
target_components()[0] == "x86_64"
}
fn is_x86_32() -> bool {
let arch = &target_components()[0];
arch == "i386" || arch == "i586" || arch == "i686"
}
fn is_armv7() -> bool {
target_components()[0] == "armv7"
}
fn is_aarch64() -> bool {
target_components()[0] == "aarch64"
}
// Windows targets may be using the MSVC toolchain or the GNU toolchain. The
// right compiler flags to use depend on the toolchain. (And we don't want to
// use flag_if_supported, because we don't want features to be silently
// disabled by old compilers.)
fn is_windows_msvc() -> bool {
// Some targets are only two components long, so check in steps.
target_components()[1] == "pc"
&& target_components()[2] == "windows"
&& target_components()[3] == "msvc"
}
fn is_windows_gnu() -> bool {
// Some targets are only two components long, so check in steps.
target_components()[1] == "pc"
&& target_components()[2] == "windows"
&& target_components()[3] == "gnu"
}
fn new_build() -> cc::Build {
let mut build = cc::Build::new();
if !is_windows_msvc() {
build.flag("-std=c11");
}
build
}
fn c_dir_path(filename: &str) -> String {
// The `cross` tool doesn't support reading files in parent directories. As a hacky workaround
// in `cross_test.sh`, we move the c/ directory around and set BLAKE3_C_DIR_OVERRIDE. Regular
// building and testing doesn't require this.
if let Ok(c_dir_override) = env::var("BLAKE3_C_DIR_OVERRIDE") {
c_dir_override + "/" + filename
} else {
"../".to_string() + filename
}
}
fn main() -> Result<(), Box<dyn std::error::Error>> {
let mut base_build = new_build();
base_build.file(c_dir_path("blake3.c"));
base_build.file(c_dir_path("blake3_dispatch.c"));
base_build.file(c_dir_path("blake3_portable.c"));
base_build.compile("blake3_base");
if is_x86_64() && !defined("CARGO_FEATURE_PREFER_INTRINSICS") {
// On 64-bit, use the assembly implementations, unless the
// "prefer_intrinsics" feature is enabled.
if is_windows_msvc() {
let mut build = new_build();
build.file(c_dir_path("blake3_sse2_x86-64_windows_msvc.asm"));
build.file(c_dir_path("blake3_sse41_x86-64_windows_msvc.asm"));
build.file(c_dir_path("blake3_avx2_x86-64_windows_msvc.asm"));
build.file(c_dir_path("blake3_avx512_x86-64_windows_msvc.asm"));
build.compile("blake3_asm");
} else if is_windows_gnu() {
let mut build = new_build();
build.file(c_dir_path("blake3_sse2_x86-64_windows_gnu.S"));
build.file(c_dir_path("blake3_sse41_x86-64_windows_gnu.S"));
build.file(c_dir_path("blake3_avx2_x86-64_windows_gnu.S"));
build.file(c_dir_path("blake3_avx512_x86-64_windows_gnu.S"));
build.compile("blake3_asm");
} else {
// All non-Windows implementations are assumed to support
// Linux-style assembly. These files do contain a small
// explicit workaround for macOS also.
let mut build = new_build();
build.file(c_dir_path("blake3_sse2_x86-64_unix.S"));
build.file(c_dir_path("blake3_sse41_x86-64_unix.S"));
build.file(c_dir_path("blake3_avx2_x86-64_unix.S"));
build.file(c_dir_path("blake3_avx512_x86-64_unix.S"));
build.compile("blake3_asm");
}
} else if is_x86_64() || is_x86_32() {
// Assembly implementations are only for 64-bit. On 32-bit, or if
// the "prefer_intrinsics" feature is enabled, use the
// intrinsics-based C implementations. These each need to be
// compiled separately, with the corresponding instruction set
// extension explicitly enabled in the compiler.
let mut sse2_build = new_build();
sse2_build.file(c_dir_path("blake3_sse2.c"));
if is_windows_msvc() {
// /arch:SSE2 is the default on x86 and undefined on x86_64:
// https://docs.microsoft.com/en-us/cpp/build/reference/arch-x86
// It also includes SSE4.1 intrinsics:
// https://stackoverflow.com/a/32183222/823869
} else {
sse2_build.flag("-msse2");
}
sse2_build.compile("blake3_sse2");
let mut sse41_build = new_build();
sse41_build.file(c_dir_path("blake3_sse41.c"));
if is_windows_msvc() {
// /arch:SSE2 is the default on x86 and undefined on x86_64:
// https://docs.microsoft.com/en-us/cpp/build/reference/arch-x86
// It also includes SSE4.1 intrinsics:
// https://stackoverflow.com/a/32183222/823869
} else {
sse41_build.flag("-msse4.1");
}
sse41_build.compile("blake3_sse41");
let mut avx2_build = new_build();
avx2_build.file(c_dir_path("blake3_avx2.c"));
if is_windows_msvc() {
avx2_build.flag("/arch:AVX2");
} else {
avx2_build.flag("-mavx2");
}
avx2_build.compile("blake3_avx2");
let mut avx512_build = new_build();
avx512_build.file(c_dir_path("blake3_avx512.c"));
if is_windows_msvc() {
// Note that a lot of versions of MSVC don't support /arch:AVX512,
// and they'll discard it with a warning, hopefully leading to a
// build error.
avx512_build.flag("/arch:AVX512");
} else {
avx512_build.flag("-mavx512f");
avx512_build.flag("-mavx512vl");
}
avx512_build.compile("blake3_avx512");
}
// We only build NEON code here if
// 1) it's requested
// and 2) the root crate is not already building it.
// The only time this will really happen is if you build this
// crate by hand with the "neon" feature for some reason.
//
// In addition, 3) if the target is aarch64, NEON is on by default.
if defined("CARGO_FEATURE_NEON") || is_aarch64() {
let mut neon_build = new_build();
neon_build.file(c_dir_path("blake3_neon.c"));
// ARMv7 platforms that support NEON generally need the following
// flags. AArch64 supports NEON by default and does not support -mpfu.
if is_armv7() {
neon_build.flag("-mfpu=neon-vfpv4");
neon_build.flag("-mfloat-abi=hard");
}
neon_build.compile("blake3_neon");
}
// The `cc` crate does not automatically emit rerun-if directives for the
// environment variables it supports, in particular for $CC. We expect to
// do a lot of benchmarking across different compilers, so we explicitly
// add the variables that we're likely to need.
println!("cargo:rerun-if-env-changed=CC");
println!("cargo:rerun-if-env-changed=CFLAGS");
// Ditto for source files, though these shouldn't change as often. `ignore::Walk` respects
// .gitignore, so this doesn't traverse target/.
for result in ignore::Walk::new("..") {
let result = result?;
let path = result.path();
if path.is_file() {
println!("cargo:rerun-if-changed={}", path.to_str().unwrap());
}
}
Ok(())
}
|
