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Implement LLVM's elementwise unordered atomic memory intrinsics

Allows uses of intrinsics of the form
llvm.(memcpy|memmove|memset).element.unordered.atomic.* to be linked.
master
Benjamin Saunders 2 years ago
parent
commit
997b86d767
  1. 106
      src/mem.rs

106
src/mem.rs

@ -5,6 +5,10 @@ type c_int = i16;
#[cfg(not(target_pointer_width = "16"))]
type c_int = i32;
use core::intrinsics::{atomic_load_unordered, atomic_store_unordered, unchecked_div};
use core::mem;
use core::ops::{BitOr, Shl};
#[cfg_attr(all(feature = "mem", not(feature = "mangled-names")), no_mangle)]
pub unsafe extern "C" fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
let mut i = 0;
@ -58,3 +62,105 @@ pub unsafe extern "C" fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
}
0
}
fn memcpy_element_unordered_atomic<T: Copy>(dest: *mut T, src: *const T, bytes: usize) {
unsafe {
let n = unchecked_div(bytes, mem::size_of::<T>());
let mut i = 0;
while i < n {
atomic_store_unordered(dest.add(i), atomic_load_unordered(src.add(i)));
i += 1;
}
}
}
fn memmove_element_unordered_atomic<T: Copy>(dest: *mut T, src: *const T, bytes: usize) {
unsafe {
let n = unchecked_div(bytes, mem::size_of::<T>());
if src < dest as *const T {
// copy from end
let mut i = n;
while i != 0 {
i -= 1;
atomic_store_unordered(dest.add(i), atomic_load_unordered(src.add(i)));
}
} else {
// copy from beginning
let mut i = 0;
while i < n {
atomic_store_unordered(dest.add(i), atomic_load_unordered(src.add(i)));
i += 1;
}
}
}
}
fn memset_element_unordered_atomic<T>(s: *mut T, c: u8, bytes: usize)
where
T: Copy + From<u8> + Shl<u32, Output = T> + BitOr<T, Output = T>,
{
unsafe {
let n = unchecked_div(bytes, mem::size_of::<T>());
let mut x = T::from(c);
let mut i = 1;
while i < mem::size_of::<T>() {
x = x << 8 | T::from(c);
i += 1;
}
let mut i = 0;
while i < n {
atomic_store_unordered(s.add(i), x);
i += 1;
}
}
}
intrinsics! {
pub extern "C" fn __llvm_memcpy_element_unordered_atomic_1(dest: *mut u8, src: *const u8, bytes: usize) -> () {
memcpy_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memcpy_element_unordered_atomic_2(dest: *mut u16, src: *const u16, bytes: usize) -> () {
memcpy_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memcpy_element_unordered_atomic_4(dest: *mut u32, src: *const u32, bytes: usize) -> () {
memcpy_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memcpy_element_unordered_atomic_8(dest: *mut u64, src: *const u64, bytes: usize) -> () {
memcpy_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memcpy_element_unordered_atomic_16(dest: *mut u128, src: *const u128, bytes: usize) -> () {
memcpy_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memmove_element_unordered_atomic_1(dest: *mut u8, src: *const u8, bytes: usize) -> () {
memmove_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memmove_element_unordered_atomic_2(dest: *mut u16, src: *const u16, bytes: usize) -> () {
memmove_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memmove_element_unordered_atomic_4(dest: *mut u32, src: *const u32, bytes: usize) -> () {
memmove_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memmove_element_unordered_atomic_8(dest: *mut u64, src: *const u64, bytes: usize) -> () {
memmove_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memmove_element_unordered_atomic_16(dest: *mut u128, src: *const u128, bytes: usize) -> () {
memmove_element_unordered_atomic(dest, src, bytes);
}
pub extern "C" fn __llvm_memset_element_unordered_atomic_1(s: *mut u8, c: u8, bytes: usize) -> () {
memset_element_unordered_atomic(s, c, bytes);
}
pub extern "C" fn __llvm_memset_element_unordered_atomic_2(s: *mut u16, c: u8, bytes: usize) -> () {
memset_element_unordered_atomic(s, c, bytes);
}
pub extern "C" fn __llvm_memset_element_unordered_atomic_4(s: *mut u32, c: u8, bytes: usize) -> () {
memset_element_unordered_atomic(s, c, bytes);
}
pub extern "C" fn __llvm_memset_element_unordered_atomic_8(s: *mut u64, c: u8, bytes: usize) -> () {
memset_element_unordered_atomic(s, c, bytes);
}
pub extern "C" fn __llvm_memset_element_unordered_atomic_16(s: *mut u128, c: u8, bytes: usize) -> () {
memset_element_unordered_atomic(s, c, bytes);
}
}
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