Make a subset of libm symbols weakly available on all platforms
018616e78b ("Always have math functions but with `weak` linking
attribute if we can") made all math symbols available on platforms that
support weak linkage. This caused some unexpected regressions, however,
because our less accurate and sometimes slow routines were being
selected over the system `libm`, which also tends to be weak [1]. Thus,
0fab77e8d7 ("Don't include `math` for `unix` and `wasi` targets") was
applied to undo these changes on many platforms.
Now that some improvements have been made to `libm`, add back a subset
of these functions:
* cbrt
* ceil
* copysign
* fabs
* fdim
* floor
* fma
* fmax
* fmaximum
* fmin
* fminimum
* fmod
* rint
* round
* roundeven
* sqrt
* trunc
This list includes only functions that produce exact results (verified
with exhaustive / extensive tests, and also required by IEEE in most
cases), and for which benchmarks indicate performance similar to or
better than Musl's soft float math routines [^1]. All except `cbrt` also
have `f16` and `f128` implementations. Once more routines meet these
criteria, we can move them from platform-specific availability to always
available.
Once this change makes it to rust-lang/rust, we will also be able to
move the relevant functions from `std` to `core`.
[^1]: We still rely on the backend to provide optimized assmebly
routines when available.
[1]: https://github.com/rust-lang/rust/issues/128386
This commit is contained in:
Trevor Gross
Trevor Gross
parent
95a5ad5225
commit
55bbda8ff8
2 changed files with 179 additions and 121 deletions
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@ -41,40 +41,13 @@ mod macros;
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pub mod float;
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pub mod int;
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// Disable for any of the following:
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// - x86 without sse2 due to ABI issues
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// - <https://github.com/rust-lang/rust/issues/114479>
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// - but exclude UEFI since it is a soft-float target
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// - <https://github.com/rust-lang/rust/issues/128533>
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// - All unix targets (linux, macos, freebsd, android, etc)
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// - wasm with known target_os
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#[cfg(not(any(
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all(
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target_arch = "x86",
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not(target_feature = "sse2"),
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not(target_os = "uefi"),
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),
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unix,
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all(target_family = "wasm", not(target_os = "unknown"))
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)))]
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pub mod math;
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pub mod mem;
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// `libm` expects its `support` module to be available in the crate root. This config can be
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// cleaned up once `libm` is made always available.
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#[cfg(not(any(
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all(
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target_arch = "x86",
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not(target_feature = "sse2"),
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not(target_os = "uefi"),
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),
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unix,
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all(target_family = "wasm", not(target_os = "unknown"))
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)))]
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use math::libm::support;
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pub mod mem;
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#[cfg(target_arch = "arm")]
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pub mod arm;
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@ -5,110 +5,195 @@
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#[path = "../libm/src/math/mod.rs"]
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pub(crate) mod libm;
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#[allow(unused_macros)]
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macro_rules! no_mangle {
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macro_rules! libm_intrinsics {
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($(fn $fun:ident($($iid:ident : $ity:ty),+) -> $oty:ty;)+) => {
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intrinsics! {
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$(
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pub extern "C" fn $fun($($iid: $ity),+) -> $oty {
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self::libm::$fun($($iid),+)
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$crate::math::libm::$fun($($iid),+)
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}
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)+
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}
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}
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}
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#[cfg(not(windows))]
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no_mangle! {
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fn acos(x: f64) -> f64;
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fn asin(x: f64) -> f64;
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fn cbrt(x: f64) -> f64;
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fn expm1(x: f64) -> f64;
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fn hypot(x: f64, y: f64) -> f64;
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fn tan(x: f64) -> f64;
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fn cos(x: f64) -> f64;
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fn expf(x: f32) -> f32;
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fn log2(x: f64) -> f64;
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fn log2f(x: f32) -> f32;
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fn log10(x: f64) -> f64;
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fn log10f(x: f32) -> f32;
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fn log(x: f64) -> f64;
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fn logf(x: f32) -> f32;
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fn round(x: f64) -> f64;
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fn roundf(x: f32) -> f32;
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fn rint(x: f64) -> f64;
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fn rintf(x: f32) -> f32;
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fn sin(x: f64) -> f64;
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fn pow(x: f64, y: f64) -> f64;
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fn powf(x: f32, y: f32) -> f32;
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fn acosf(n: f32) -> f32;
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fn atan2f(a: f32, b: f32) -> f32;
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fn atanf(n: f32) -> f32;
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fn coshf(n: f32) -> f32;
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fn expm1f(n: f32) -> f32;
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fn fdim(a: f64, b: f64) -> f64;
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fn fdimf(a: f32, b: f32) -> f32;
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fn log1pf(n: f32) -> f32;
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fn sinhf(n: f32) -> f32;
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fn tanhf(n: f32) -> f32;
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fn ldexp(f: f64, n: i32) -> f64;
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fn ldexpf(f: f32, n: i32) -> f32;
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fn tgamma(x: f64) -> f64;
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fn tgammaf(x: f32) -> f32;
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fn atan(x: f64) -> f64;
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fn atan2(x: f64, y: f64) -> f64;
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fn cosh(x: f64) -> f64;
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fn log1p(x: f64) -> f64;
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fn sinh(x: f64) -> f64;
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fn tanh(x: f64) -> f64;
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fn cosf(x: f32) -> f32;
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fn exp(x: f64) -> f64;
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fn sinf(x: f32) -> f32;
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fn exp2(x: f64) -> f64;
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fn exp2f(x: f32) -> f32;
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fn fma(x: f64, y: f64, z: f64) -> f64;
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fn fmaf(x: f32, y: f32, z: f32) -> f32;
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fn asinf(n: f32) -> f32;
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fn cbrtf(n: f32) -> f32;
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fn hypotf(x: f32, y: f32) -> f32;
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fn tanf(n: f32) -> f32;
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fn sqrtf(x: f32) -> f32;
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fn sqrt(x: f64) -> f64;
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fn ceil(x: f64) -> f64;
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fn ceilf(x: f32) -> f32;
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fn floor(x: f64) -> f64;
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fn floorf(x: f32) -> f32;
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fn trunc(x: f64) -> f64;
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fn truncf(x: f32) -> f32;
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fn fmin(x: f64, y: f64) -> f64;
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fn fminf(x: f32, y: f32) -> f32;
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fn fmax(x: f64, y: f64) -> f64;
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fn fmaxf(x: f32, y: f32) -> f32;
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// `f64 % f64`
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fn fmod(x: f64, y: f64) -> f64;
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// `f32 % f32`
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fn fmodf(x: f32, y: f32) -> f32;
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fn erf(x: f64) -> f64;
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fn erff(x: f32) -> f32;
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fn erfc(x: f64) -> f64;
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fn erfcf(x: f32) -> f32;
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}
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// allow for windows (and other targets)
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intrinsics! {
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pub extern "C" fn lgamma_r(x: f64, s: &mut i32) -> f64 {
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let r = self::libm::lgamma_r(x);
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*s = r.1;
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r.0
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/// This set of functions is well tested in `libm` and known to provide similar performance to
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/// system `libm`, as well as the same or better accuracy.
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pub mod full_availability {
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#[cfg(f16_enabled)]
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libm_intrinsics! {
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fn ceilf16(x: f16) -> f16;
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fn copysignf16(x: f16, y: f16) -> f16;
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fn fabsf16(x: f16) -> f16;
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fn fdimf16(x: f16, y: f16) -> f16;
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fn floorf16(x: f16) -> f16;
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fn fmaxf16(x: f16, y: f16) -> f16;
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fn fmaximumf16(x: f16, y: f16) -> f16;
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fn fminf16(x: f16, y: f16) -> f16;
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fn fminimumf16(x: f16, y: f16) -> f16;
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fn fmodf16(x: f16, y: f16) -> f16;
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fn rintf16(x: f16) -> f16;
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fn roundevenf16(x: f16) -> f16;
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fn roundf16(x: f16) -> f16;
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fn sqrtf16(x: f16) -> f16;
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fn truncf16(x: f16) -> f16;
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}
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pub extern "C" fn lgammaf_r(x: f32, s: &mut i32) -> f32 {
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let r = self::libm::lgammaf_r(x);
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*s = r.1;
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r.0
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/* Weak linkage is unreliable on Windows and Apple, so we don't expose symbols that we know
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* the system libc provides in order to avoid conflicts. */
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#[cfg(all(not(windows), not(target_vendor = "apple")))]
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libm_intrinsics! {
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/* f32 */
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fn cbrtf(n: f32) -> f32;
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fn ceilf(x: f32) -> f32;
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fn copysignf(x: f32, y: f32) -> f32;
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fn fabsf(x: f32) -> f32;
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fn fdimf(a: f32, b: f32) -> f32;
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fn floorf(x: f32) -> f32;
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fn fmaf(x: f32, y: f32, z: f32) -> f32;
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fn fmaxf(x: f32, y: f32) -> f32;
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fn fminf(x: f32, y: f32) -> f32;
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fn fmodf(x: f32, y: f32) -> f32;
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fn rintf(x: f32) -> f32;
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fn roundf(x: f32) -> f32;
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fn sqrtf(x: f32) -> f32;
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fn truncf(x: f32) -> f32;
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/* f64 */
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fn cbrt(x: f64) -> f64;
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fn ceil(x: f64) -> f64;
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fn copysign(x: f64, y: f64) -> f64;
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fn fabs(x: f64) -> f64;
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fn fdim(a: f64, b: f64) -> f64;
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fn floor(x: f64) -> f64;
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fn fma(x: f64, y: f64, z: f64) -> f64;
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fn fmax(x: f64, y: f64) -> f64;
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fn fmin(x: f64, y: f64) -> f64;
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fn fmod(x: f64, y: f64) -> f64;
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fn rint(x: f64) -> f64;
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fn round(x: f64) -> f64;
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fn sqrt(x: f64) -> f64;
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fn trunc(x: f64) -> f64;
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}
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// Windows and MacOS do not yet expose roundeven and IEEE 754-2019 `maximum` / `minimum`,
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// however, so we still provide a fallback.
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libm_intrinsics! {
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fn fmaximum(x: f64, y: f64) -> f64;
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fn fmaximumf(x: f32, y: f32) -> f32;
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fn fminimum(x: f64, y: f64) -> f64;
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fn fminimumf(x: f32, y: f32) -> f32;
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fn roundeven(x: f64) -> f64;
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fn roundevenf(x: f32) -> f32;
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}
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#[cfg(f128_enabled)]
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libm_intrinsics! {
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fn ceilf128(x: f128) -> f128;
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fn copysignf128(x: f128, y: f128) -> f128;
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fn fabsf128(x: f128) -> f128;
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fn fdimf128(x: f128, y: f128) -> f128;
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fn floorf128(x: f128) -> f128;
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fn fmaf128(x: f128, y: f128, z: f128) -> f128;
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fn fmaxf128(x: f128, y: f128) -> f128;
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fn fmaximumf128(x: f128, y: f128) -> f128;
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fn fminf128(x: f128, y: f128) -> f128;
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fn fminimumf128(x: f128, y: f128) -> f128;
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fn fmodf128(x: f128, y: f128) -> f128;
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fn rintf128(x: f128) -> f128;
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fn roundevenf128(x: f128) -> f128;
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fn roundf128(x: f128) -> f128;
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fn sqrtf128(x: f128) -> f128;
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fn truncf128(x: f128) -> f128;
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}
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}
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/// This group of functions has more performance or precision issues than system versions, or
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/// are otherwise less well tested. Provide them only on platforms that have problems with the
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/// system `libm`.
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///
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/// As `libm` improves, more functions will be moved from this group to the first group.
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///
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/// Do not supply for any of the following:
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/// - x86 without sse2 due to ABI issues
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/// - <https://github.com/rust-lang/rust/issues/114479>
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/// - but exclude UEFI since it is a soft-float target
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/// - <https://github.com/rust-lang/rust/issues/128533>
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/// - All unix targets (linux, macos, freebsd, android, etc)
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/// - wasm with known target_os
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#[cfg(not(any(
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all(
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target_arch = "x86",
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not(target_feature = "sse2"),
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not(target_os = "uefi"),
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),
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unix,
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all(target_family = "wasm", not(target_os = "unknown"))
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)))]
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pub mod partial_availability {
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#[cfg(not(windows))]
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libm_intrinsics! {
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fn acos(x: f64) -> f64;
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fn acosf(n: f32) -> f32;
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fn asin(x: f64) -> f64;
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fn asinf(n: f32) -> f32;
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fn atan(x: f64) -> f64;
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fn atan2(x: f64, y: f64) -> f64;
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fn atan2f(a: f32, b: f32) -> f32;
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fn atanf(n: f32) -> f32;
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fn cos(x: f64) -> f64;
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fn cosf(x: f32) -> f32;
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fn cosh(x: f64) -> f64;
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fn coshf(n: f32) -> f32;
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fn erf(x: f64) -> f64;
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fn erfc(x: f64) -> f64;
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fn erfcf(x: f32) -> f32;
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fn erff(x: f32) -> f32;
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fn exp(x: f64) -> f64;
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fn exp2(x: f64) -> f64;
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fn exp2f(x: f32) -> f32;
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fn expf(x: f32) -> f32;
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fn expm1(x: f64) -> f64;
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fn expm1f(n: f32) -> f32;
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fn hypot(x: f64, y: f64) -> f64;
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fn hypotf(x: f32, y: f32) -> f32;
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fn ldexp(f: f64, n: i32) -> f64;
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fn ldexpf(f: f32, n: i32) -> f32;
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fn log(x: f64) -> f64;
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fn log10(x: f64) -> f64;
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fn log10f(x: f32) -> f32;
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fn log1p(x: f64) -> f64;
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fn log1pf(n: f32) -> f32;
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fn log2(x: f64) -> f64;
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fn log2f(x: f32) -> f32;
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fn logf(x: f32) -> f32;
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fn pow(x: f64, y: f64) -> f64;
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fn powf(x: f32, y: f32) -> f32;
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fn sin(x: f64) -> f64;
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fn sinf(x: f32) -> f32;
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fn sinh(x: f64) -> f64;
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fn sinhf(n: f32) -> f32;
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fn tan(x: f64) -> f64;
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fn tanf(n: f32) -> f32;
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fn tanh(x: f64) -> f64;
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fn tanhf(n: f32) -> f32;
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fn tgamma(x: f64) -> f64;
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fn tgammaf(x: f32) -> f32;
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}
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// allow for windows (and other targets)
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intrinsics! {
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pub extern "C" fn lgamma_r(x: f64, s: &mut i32) -> f64 {
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let r = super::libm::lgamma_r(x);
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*s = r.1;
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r.0
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}
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pub extern "C" fn lgammaf_r(x: f32, s: &mut i32) -> f32 {
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let r = super::libm::lgammaf_r(x);
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*s = r.1;
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r.0
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}
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}
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}
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|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue