compiler_builtins/mem/
mod.rs

1// Trying to satisfy clippy here is hopeless
2#![allow(clippy::style)]
3// FIXME(e2024): this eventually needs to be removed.
4#![allow(unsafe_op_in_unsafe_fn)]
5
6#[allow(warnings)]
7#[cfg(target_pointer_width = "16")]
8type c_int = i16;
9#[allow(warnings)]
10#[cfg(not(target_pointer_width = "16"))]
11type c_int = i32;
12
13// memcpy/memmove/memset have optimized implementations on some architectures
14#[cfg_attr(
15    all(not(feature = "no-asm"), target_arch = "x86_64"),
16    path = "x86_64.rs"
17)]
18mod impls;
19
20intrinsics! {
21    #[mem_builtin]
22    pub unsafe extern "C" fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
23        impls::copy_forward(dest, src, n);
24        dest
25    }
26
27    #[mem_builtin]
28    pub unsafe extern "C" fn memmove(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
29        let delta = (dest as usize).wrapping_sub(src as usize);
30        if delta >= n {
31            // We can copy forwards because either dest is far enough ahead of src,
32            // or src is ahead of dest (and delta overflowed).
33            impls::copy_forward(dest, src, n);
34        } else {
35            impls::copy_backward(dest, src, n);
36        }
37        dest
38    }
39
40    #[mem_builtin]
41    pub unsafe extern "C" fn memset(s: *mut u8, c: crate::mem::c_int, n: usize) -> *mut u8 {
42        impls::set_bytes(s, c as u8, n);
43        s
44    }
45
46    #[mem_builtin]
47    pub unsafe extern "C" fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
48        impls::compare_bytes(s1, s2, n)
49    }
50
51    #[mem_builtin]
52    pub unsafe extern "C" fn bcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
53        memcmp(s1, s2, n)
54    }
55
56    #[mem_builtin]
57    pub unsafe extern "C" fn strlen(s: *const core::ffi::c_char) -> usize {
58        impls::c_string_length(s)
59    }
60}
compiler_builtins/mem/mod.rs

compiler_builtins/mem/
mod.rs
