Delete architecture-specific memchr code in std::sys

Currently all architecture-specific memchr code is only used in
`std::io`. Most of the actual `memchr` capacity exposed to the user
through the slice API is instead implemented in core::slice::memchr.

Hence this commit deletes memchr from std::sys[_common] and replace
calls to it by calls to core::slice::memchr functions. This deletes
(r)memchr from the list of symbols linked to libc.

3 files changed, 0 insertions, 138 deletions

diff --git a/library/std/src/sys_common/memchr.rs b/library/std/src/sys_common/memchr.rs
deleted file mode 100644
index b219e878912..00000000000
--- a/library/std/src/sys_common/memchr.rs
+++ /dev/null
@@ -1,51 +0,0 @@
-// Original implementation taken from rust-memchr.
-// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
-
-use crate::sys::memchr as sys;
-
-#[cfg(test)]
-mod tests;
-
-/// A safe interface to `memchr`.
-///
-/// Returns the index corresponding to the first occurrence of `needle` in
-/// `haystack`, or `None` if one is not found.
-///
-/// memchr reduces to super-optimized machine code at around an order of
-/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
-/// (See benchmarks.)
-///
-/// # Examples
-///
-/// This shows how to find the first position of a byte in a byte string.
-///
-/// ```ignore (cannot-doctest-private-modules)
-/// use memchr::memchr;
-///
-/// let haystack = b"the quick brown fox";
-/// assert_eq!(memchr(b'k', haystack), Some(8));
-/// ```
-#[inline]
-pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
-    sys::memchr(needle, haystack)
-}
-
-/// A safe interface to `memrchr`.
-///
-/// Returns the index corresponding to the last occurrence of `needle` in
-/// `haystack`, or `None` if one is not found.
-///
-/// # Examples
-///
-/// This shows how to find the last position of a byte in a byte string.
-///
-/// ```ignore (cannot-doctest-private-modules)
-/// use memchr::memrchr;
-///
-/// let haystack = b"the quick brown fox";
-/// assert_eq!(memrchr(b'o', haystack), Some(17));
-/// ```
-#[inline]
-pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
-    sys::memrchr(needle, haystack)
-}
diff --git a/library/std/src/sys_common/memchr/tests.rs b/library/std/src/sys_common/memchr/tests.rs
deleted file mode 100644
index 557d749c7f6..00000000000
--- a/library/std/src/sys_common/memchr/tests.rs
+++ /dev/null
@@ -1,86 +0,0 @@
-// Original implementation taken from rust-memchr.
-// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
-
-// test the implementations for the current platform
-use super::{memchr, memrchr};
-
-#[test]
-fn matches_one() {
-    assert_eq!(Some(0), memchr(b'a', b"a"));
-}
-
-#[test]
-fn matches_begin() {
-    assert_eq!(Some(0), memchr(b'a', b"aaaa"));
-}
-
-#[test]
-fn matches_end() {
-    assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
-}
-
-#[test]
-fn matches_nul() {
-    assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
-}
-
-#[test]
-fn matches_past_nul() {
-    assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
-}
-
-#[test]
-fn no_match_empty() {
-    assert_eq!(None, memchr(b'a', b""));
-}
-
-#[test]
-fn no_match() {
-    assert_eq!(None, memchr(b'a', b"xyz"));
-}
-
-#[test]
-fn matches_one_reversed() {
-    assert_eq!(Some(0), memrchr(b'a', b"a"));
-}
-
-#[test]
-fn matches_begin_reversed() {
-    assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
-}
-
-#[test]
-fn matches_end_reversed() {
-    assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
-}
-
-#[test]
-fn matches_nul_reversed() {
-    assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
-}
-
-#[test]
-fn matches_past_nul_reversed() {
-    assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
-}
-
-#[test]
-fn no_match_empty_reversed() {
-    assert_eq!(None, memrchr(b'a', b""));
-}
-
-#[test]
-fn no_match_reversed() {
-    assert_eq!(None, memrchr(b'a', b"xyz"));
-}
-
-#[test]
-fn each_alignment() {
-    let mut data = [1u8; 64];
-    let needle = 2;
-    let pos = 40;
-    data[pos] = needle;
-    for start in 0..16 {
-        assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
-    }
-}
diff --git a/library/std/src/sys_common/mod.rs b/library/std/src/sys_common/mod.rs
index 01f83ecb414..c9025a81bf3 100644
--- a/library/std/src/sys_common/mod.rs
+++ b/library/std/src/sys_common/mod.rs
@@ -24,7 +24,6 @@ pub mod backtrace;
 pub mod fs;
 pub mod io;
 pub mod lazy_box;
-pub mod memchr;
 pub mod once;
 pub mod process;
 pub mod thread;