This commit is contained in:
Terence
2021-06-01 21:27:51 -04:00
parent 94993901cd
commit 16fd97595d

View File

@@ -677,28 +677,32 @@ impl Drop for FlushToZeroDenormalsAreZeroFlags {
// code that is generating NaNs and infinite values erroneously.
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct DisableFloatingPointExceptionsFlags {
original_flags: c_int,
#[cfg(feature = "avoid-fe-exceptions")]
// We can't get a precise size for this, because it's of type
// `fenv_t`, which is a definition that doesn't exist in rust
// (not even in the libc crate, as of the time of writing.)
// But since the state is intended to be stored on the stack,
// 256 bytes should be more than enough.
original_flags: [u8; 256],
}
#[cfg(feature = "avoid-fe-exceptions")]
extern "C" {
fn feenableexcept(flags: c_int);
fn fecleareexcept(flags: c_int);
fn fetestexcept(flags: c_int) -> c_int;
static FE_ALL_EXCEPT: c_int;
fn feholdexcept(env: *mut std::ffi::c_void);
fn fesetenv(env: *const std::ffi::c_void);
}
impl DisableFloatingPointExceptionsFlags {
#[cfg(not(feature = "avoid-fe-exceptions"))]
pub fn disable_floating_point_exceptions() -> Self {
Self { original_flags: 0 }
Self { }
}
#[cfg(feature = "avoid-fe-exceptions")]
pub fn disable_floating_point_exceptions() -> Self {
unsafe {
let original_flags = fetestexcept(FE_ALL_EXCEPT);
fecleareexcept(FE_ALL_EXCEPT);
let mut original_flags = [0; 256];
feholdexcept(original_flags.as_mut_ptr() as *mut _);
Self { original_flags }
}
}
@@ -708,7 +712,7 @@ impl DisableFloatingPointExceptionsFlags {
impl Drop for DisableFloatingPointExceptionsFlags {
fn drop(&mut self) {
unsafe {
feenableexcept(self.original_flags);
fesetenv(self.original_flags.as_ptr() as *const _);
}
}
}