Make all public APIs extern C to enforce nounwind and C API compat

Author: gnzlbg

crates/libm-analyze/src/lib.rs

@@ -212,24 +212,18 @@ fn get_functions(files: &[syn::File]) -> Vec<FnSig> {
                 ));
             }
             if attrs.is_empty() {
-                err!(format!(
-                    "missing `#[inline]` and `#[no_panic]` attributes"
-                ));
+                err!(format!("missing `#[inline]` and `#[no_panic]` attributes"));
             } else {
                 let attrs = attrs
                     .iter()
                     .map(|a| syn_to_str!(a))
                     .collect::<Vec<_>>()
                     .join(",");
                 if !attrs.contains("inline") {
-                    err!(format!(
-                        "missing `#[inline]` attribute"
-                    ));
+                    err!(format!("missing `#[inline]` attribute"));
                 }
                 if !attrs.contains("no_panic") {
-                    err!(format!(
-                        "missing `#[no_panic]` attributes"
-                    ));
+                    err!(format!("missing `#[no_panic]` attributes"));
                 }
             }
             // Validate and parse output parameters and function arguments:

crates/libm-test/build.rs

@@ -13,9 +13,7 @@ fn main() {
 
     if profile == "release" || opt_level > 0 {
         match target.as_str() {
-            "x86_64-unknown-linux-gnu" |
-            "x86_64-apple-darwin" |
-            "x86_64-pc-windows-msvc" => {
+            "x86_64-unknown-linux-gnu" | "x86_64-apple-darwin" | "x86_64-pc-windows-msvc" => {
                 println!("cargo:rustc-cfg=exhaustive32");
             }
             _ => (),

crates/libm-test/src/lib.rs

@@ -112,9 +112,12 @@ macro_rules! assert_approx_eq {
         if !$crate::WithinUlps::within_ulps($result, $expected, $ulps) {
             let f = format!(
                 "{}{:?} returns = {:?} != {:?} (expected)",
-                stringify!($id), $arg, $result, $expected
+                stringify!($id),
+                $arg,
+                $result,
+                $expected
             );
             panic!(f);
         }
-    }
+    };
 }

crates/libm-test/tests/exhaustive32.rs

@@ -1,7 +1,7 @@
 //! Exhaustively test unary APIs taking 32-bit wide arguments.
 #![cfg(test)]
 #![cfg(exhaustive32)]
-use libm_test::{assert_approx_eq};
+use libm_test::assert_approx_eq;
 
 macro_rules! exhaustive32 {
     // Skip those parts of the API that are not

crates/libm-test/tests/system_libm.rs

@@ -2,7 +2,7 @@
 #![cfg(test)]
 #![cfg(feature = "system_libm")]
 
-use libm_test::{adjust_input, Call, assert_approx_eq};
+use libm_test::{adjust_input, assert_approx_eq, Call};
 
 // Number of tests to generate for each function
 const NTESTS: usize = 500;

crates/libm/src/math/acos.rs

@@ -62,7 +62,7 @@ fn r(z: f64) -> f64 {
 /// Returns values in radians, in the range of 0 to pi.
 #[inline]
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
-pub fn acos(x: f64) -> f64 {
+pub extern "C" fn acos(x: f64) -> f64 {
     let x1p_120f = f64::from_bits(0x3870000000000000); // 0x1p-120 === 2 ^ -120
     let z: f64;
     let w: f64;

crates/libm/src/math/acosf.rs

@@ -36,7 +36,7 @@ fn r(z: f32) -> f32 {
 /// Returns values in radians, in the range of 0 to pi.
 #[inline]
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
-pub fn acosf(x: f32) -> f32 {
+pub extern "C" fn acosf(x: f32) -> f32 {
     let x1p_120 = f32::from_bits(0x03800000); // 0x1p-120 === 2 ^ (-120)
 
     let z: f32;

crates/libm/src/math/acosh.rs

@@ -9,7 +9,7 @@ const LN2: f64 = 0.693147180559945309417232121458176568; /* 0x3fe62e42,  0xfefa3
 /// `x` must be a number greater than or equal to 1.
 #[inline]
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
-pub fn acosh(x: f64) -> f64 {
+pub extern "C" fn acosh(x: f64) -> f64 {
     let u = x.to_bits();
     let e = ((u >> 52) as usize) & 0x7ff;
 

crates/libm/src/math/acoshf.rs

@@ -9,7 +9,7 @@ const LN2: f32 = 0.693147180559945309417232121458176568;
 /// `x` must be a number greater than or equal to 1.
 #[inline]
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
-pub fn acoshf(x: f32) -> f32 {
+pub extern "C" fn acoshf(x: f32) -> f32 {
     let u = x.to_bits();
     let a = u & 0x7fffffff;
 

crates/libm/src/math/asin.rs

@@ -69,7 +69,7 @@ fn comp_r(z: f64) -> f64 {
 /// Returns values in radians, in the range of -pi/2 to pi/2.
 #[inline]
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
-pub fn asin(mut x: f64) -> f64 {
+pub extern "C" fn asin(mut x: f64) -> f64 {
     let z: f64;
     let r: f64;
     let s: f64;