Remove some `allow(unsafe_op_in_unsafe_fn)`s and use target_feature 1.1 in examples

4 files changed, 111 insertions, 71 deletions

diff --git a/library/stdarch/crates/std_detect/src/lib.rs b/library/stdarch/crates/std_detect/src/lib.rs
index 7a074529921..ab1b77bad5b 100644
--- a/library/stdarch/crates/std_detect/src/lib.rs
+++ b/library/stdarch/crates/std_detect/src/lib.rs
@@ -18,7 +18,6 @@
 #![feature(staged_api, doc_cfg, allow_internal_unstable)]
 #![deny(rust_2018_idioms)]
 #![allow(clippy::shadow_reuse)]
-#![allow(unsafe_op_in_unsafe_fn)]
 #![cfg_attr(test, allow(unused_imports))]
 #![no_std]
 #![allow(internal_features)]
diff --git a/library/stdarch/examples/connect5.rs b/library/stdarch/examples/connect5.rs
index 0a357dd429a..45d30dbe4c9 100644
--- a/library/stdarch/examples/connect5.rs
+++ b/library/stdarch/examples/connect5.rs
@@ -29,7 +29,6 @@
 //! each move.
 
 #![allow(internal_features)]
-#![allow(unsafe_op_in_unsafe_fn)]
 #![feature(avx512_target_feature)]
 #![cfg_attr(target_arch = "x86", feature(stdarch_x86_avx512, stdarch_internal))]
 #![cfg_attr(target_arch = "x86_64", feature(stdarch_x86_avx512, stdarch_internal))]
@@ -419,12 +418,12 @@ fn pos_is_draw(pos: &Pos) -> bool {
     found && !pos_is_winner(pos)
 }
 
-#[target_feature(enable = "avx512f,avx512bw")]
+#[target_feature(enable = "avx512f,avx512bw,popcnt")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn pos_is_draw_avx512(pos: &Pos) -> bool {
+fn pos_is_draw_avx512(pos: &Pos) -> bool {
     let empty = Color::Empty as usize;
 
-    let board0org = _mm512_loadu_epi32(&pos.bitboard[empty][0][0]);
+    let board0org = unsafe { _mm512_loadu_epi32(&pos.bitboard[empty][0][0]) };
 
     let answer = _mm512_set1_epi32(0);
 
@@ -481,7 +480,7 @@ fn search(pos: &Pos, alpha: i32, beta: i32, depth: i32, _ply: i32) -> i32 {
 
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     {
-        if is_x86_feature_detected!("avx512bw") {
+        if check_x86_avx512_features() {
             unsafe {
                 if pos_is_winner_avx512(pos) {
                     return -EVAL_INF + _ply;
@@ -571,7 +570,7 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
     // check if opp has live4 which will win playing next move
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     {
-        if is_x86_feature_detected!("avx512bw") {
+        if check_x86_avx512_features() {
             unsafe {
                 if check_patternlive4_avx512(pos, def) {
                     return -4096;
@@ -594,7 +593,7 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
     // check if self has live4 which will win playing next move
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     {
-        if is_x86_feature_detected!("avx512bw") {
+        if check_x86_avx512_features() {
             unsafe {
                 if check_patternlive4_avx512(pos, atk) {
                     return 2560;
@@ -617,7 +616,7 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
     // check if self has dead4 which will win playing next move
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     {
-        if is_x86_feature_detected!("avx512bw") {
+        if check_x86_avx512_features() {
             unsafe {
                 if check_patterndead4_avx512(pos, atk) > 0 {
                     return 2560;
@@ -639,7 +638,7 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
 
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     {
-        if is_x86_feature_detected!("avx512bw") {
+        if check_x86_avx512_features() {
             unsafe {
                 let n_c4: i32 = check_patterndead4_avx512(pos, def);
                 let n_c3: i32 = check_patternlive3_avx512(pos, def);
@@ -854,16 +853,18 @@ fn check_patternlive3(pos: &Pos, sd: Side) -> i32 {
     n
 }
 
-#[target_feature(enable = "avx512f,avx512bw")]
+#[target_feature(enable = "avx512f,avx512bw,popcnt")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn pos_is_winner_avx512(pos: &Pos) -> bool {
+fn pos_is_winner_avx512(pos: &Pos) -> bool {
     let current_side = side_opp(pos.p_turn);
     let coloridx = current_side as usize;
 
-    let board0org: [__m512i; 2] = [
-        _mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]),
-        _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0]),
-    ]; // load states from bitboard
+    let board0org: [__m512i; 2] = unsafe {
+        [
+            _mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]),
+            _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0]),
+        ]
+    }; // load states from bitboard
 
     #[rustfmt::skip]
     let answer = _mm512_set1_epi16((1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)); // an unbroken chain of five moves
@@ -928,9 +929,9 @@ unsafe fn pos_is_winner_avx512(pos: &Pos) -> bool {
     count_match > 0
 }
 
-#[target_feature(enable = "avx512f,avx512bw")]
+#[target_feature(enable = "avx512f,avx512bw,popcnt")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn check_patternlive4_avx512(pos: &Pos, sd: Side) -> bool {
+fn check_patternlive4_avx512(pos: &Pos, sd: Side) -> bool {
     let coloridx = sd as usize;
     let emptyidx = Color::Empty as usize;
 
@@ -952,14 +953,18 @@ unsafe fn check_patternlive4_avx512(pos: &Pos, sd: Side) -> bool {
                                         0b00_10_10_11_11_11_11_11_10_10_10_10_10_11_11_10,
                                         0b00_10_10_10_11_11_11_10_10_10_10_10_11_11_11_10,
                                         0b00_10_10_10_10_11_10_10_10_10_10_11_11_11_11_10];
-    let board0org: [__m512i; 2] = [
-        _mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]),
-        _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0]),
-    ];
-    let board1org: [__m512i; 2] = [
-        _mm512_loadu_epi32(&pos.bitboard[emptyidx][0][0]),
-        _mm512_loadu_epi32(&pos.bitboard[emptyidx][1][0]),
-    ];
+    let board0org: [__m512i; 2] = unsafe {
+        [
+            _mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]),
+            _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0]),
+        ]
+    };
+    let board1org: [__m512i; 2] = unsafe {
+        [
+            _mm512_loadu_epi32(&pos.bitboard[emptyidx][0][0]),
+            _mm512_loadu_epi32(&pos.bitboard[emptyidx][1][0]),
+        ]
+    };
 
     let mut count_match: i32 = 0;
 
@@ -990,9 +995,9 @@ unsafe fn check_patternlive4_avx512(pos: &Pos, sd: Side) -> bool {
     count_match > 0
 }
 
-#[target_feature(enable = "avx512f,avx512bw")]
+#[target_feature(enable = "avx512f,avx512bw,popcnt")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn check_patterndead4_avx512(pos: &Pos, sd: Side) -> i32 {
+fn check_patterndead4_avx512(pos: &Pos, sd: Side) -> i32 {
     let coloridx = sd as usize;
     let emptyidx = Color::Empty as usize;
 
@@ -1023,14 +1028,18 @@ unsafe fn check_patterndead4_avx512(pos: &Pos, sd: Side) -> i32 {
                                         0b00_10_10_11_11_11_11_11_10_10_10_10_11_11_11_10,
                                         0b00_10_10_10_11_11_11_10_10_10_10_11_11_11_11_10,
                                         0b00_10_10_10_10_11_10_10_10_10_11_11_11_11_11_10];
-    let board0org: [__m512i; 2] = [
-        _mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]),
-        _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0]),
-    ];
-    let board1org: [__m512i; 2] = [
-        _mm512_loadu_epi32(&pos.bitboard[emptyidx][0][0]),
-        _mm512_loadu_epi32(&pos.bitboard[emptyidx][1][0]),
-    ];
+    let board0org: [__m512i; 2] = unsafe {
+        [
+            _mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]),
+            _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0]),
+        ]
+    };
+    let board1org: [__m512i; 2] = unsafe {
+        [
+            _mm512_loadu_epi32(&pos.bitboard[emptyidx][0][0]),
+            _mm512_loadu_epi32(&pos.bitboard[emptyidx][1][0]),
+        ]
+    };
 
     let mut count_match: i32 = 0;
 
@@ -1063,16 +1072,16 @@ unsafe fn check_patterndead4_avx512(pos: &Pos, sd: Side) -> i32 {
     count_match
 }
 
-#[target_feature(enable = "avx512f,avx512bw")]
+#[target_feature(enable = "avx512f,avx512bw,popcnt")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn check_patternlive3_avx512(pos: &Pos, sd: Side) -> i32 {
+fn check_patternlive3_avx512(pos: &Pos, sd: Side) -> i32 {
     let coloridx = sd as usize;
     let emptyidx = Color::Empty as usize;
 
     #[rustfmt::skip]
-    let board0org: [__m512i; 2]  = [_mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]), _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0])];
+    let board0org: [__m512i; 2] = unsafe { [_mm512_loadu_epi32(&pos.bitboard[coloridx][0][0]), _mm512_loadu_epi32(&pos.bitboard[coloridx][1][0])] };
     #[rustfmt::skip]
-    let board1org: [__m512i; 2]  = [_mm512_loadu_epi32(&pos.bitboard[emptyidx][0][0]), _mm512_loadu_epi32(&pos.bitboard[emptyidx][1][0])];
+    let board1org: [__m512i; 2] = unsafe { [_mm512_loadu_epi32(&pos.bitboard[emptyidx][0][0]), _mm512_loadu_epi32(&pos.bitboard[emptyidx][1][0])] };
 
     #[rustfmt::skip]
     let answer_color: [__m512i; 1] = [_mm512_set1_epi16(         (1<<14)|(1<<13)|(1<<12)         )];
@@ -1170,10 +1179,15 @@ unsafe fn check_patternlive3_avx512(pos: &Pos, sd: Side) -> i32 {
     count_match
 }
 
+#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+fn check_x86_avx512_features() -> bool {
+    is_x86_feature_detected!("avx512bw") && is_x86_feature_detected!("popcnt")
+}
+
 fn main() {
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     {
-        if is_x86_feature_detected!("avx512bw") {
+        if check_x86_avx512_features() {
             println!("\n\nThe program is running with avx512f and avx512bw intrinsics\n\n");
         } else {
             println!("\n\nThe program is running with NO intrinsics.\n\n");
diff --git a/library/stdarch/examples/hex.rs b/library/stdarch/examples/hex.rs
index be42e2e41c9..e393ad72716 100644
--- a/library/stdarch/examples/hex.rs
+++ b/library/stdarch/examples/hex.rs
@@ -29,7 +29,6 @@
     clippy::cast_sign_loss,
     clippy::missing_docs_in_private_items
 )]
-#![allow(unsafe_op_in_unsafe_fn)]
 
 use std::{
     io::{self, Read},
@@ -67,7 +66,7 @@ fn hex_encode<'a>(src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
     #[cfg(target_arch = "wasm32")]
     {
         if true {
-            return unsafe { hex_encode_simd128(src, dst) };
+            return hex_encode_simd128(src, dst);
         }
     }
 
@@ -76,7 +75,9 @@ fn hex_encode<'a>(src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
 
 #[target_feature(enable = "avx2")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn hex_encode_avx2<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
+fn hex_encode_avx2<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
+    assert!(dst.len() >= src.len().checked_mul(2).unwrap());
+
     let ascii_zero = _mm256_set1_epi8(b'0' as i8);
     let nines = _mm256_set1_epi8(9);
     let ascii_a = _mm256_set1_epi8((b'a' - 9 - 1) as i8);
@@ -84,7 +85,8 @@ unsafe fn hex_encode_avx2<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a s
 
     let mut i = 0_usize;
     while src.len() >= 32 {
-        let invec = _mm256_loadu_si256(src.as_ptr() as *const _);
+        // SAFETY: the loop condition ensures that we have at least 32 bytes
+        let invec = unsafe { _mm256_loadu_si256(src.as_ptr() as *const _) };
 
         let masked1 = _mm256_and_si256(invec, and4bits);
         let masked2 = _mm256_and_si256(_mm256_srli_epi64(invec, 4), and4bits);
@@ -102,26 +104,34 @@ unsafe fn hex_encode_avx2<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a s
         let res2 = _mm256_unpackhi_epi8(masked2, masked1);
 
         // Store everything into the right destination now
-        let base = dst.as_mut_ptr().add(i * 2);
-        let base1 = base.add(0) as *mut _;
-        let base2 = base.add(16) as *mut _;
-        let base3 = base.add(32) as *mut _;
-        let base4 = base.add(48) as *mut _;
-        _mm256_storeu2_m128i(base3, base1, res1);
-        _mm256_storeu2_m128i(base4, base2, res2);
+        unsafe {
+            // SAFETY: the assertion at the beginning of the function ensures
+            // that `dst` is large enough.
+            let base = dst.as_mut_ptr().add(i * 2);
+            let base1 = base.add(0) as *mut _;
+            let base2 = base.add(16) as *mut _;
+            let base3 = base.add(32) as *mut _;
+            let base4 = base.add(48) as *mut _;
+            _mm256_storeu2_m128i(base3, base1, res1);
+            _mm256_storeu2_m128i(base4, base2, res2);
+        }
+
         src = &src[32..];
         i += 32;
     }
 
     let _ = hex_encode_sse41(src, &mut dst[i * 2..]);
 
-    Ok(str::from_utf8_unchecked(&dst[..src.len() * 2 + i * 2]))
+    // SAFETY: `dst` only contains ASCII characters
+    unsafe { Ok(str::from_utf8_unchecked(&dst[..src.len() * 2 + i * 2])) }
 }
 
 // copied from https://github.com/Matherunner/bin2hex-sse/blob/master/base16_sse4.cpp
 #[target_feature(enable = "sse4.1")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-unsafe fn hex_encode_sse41<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
+fn hex_encode_sse41<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
+    assert!(dst.len() >= src.len().checked_mul(2).unwrap());
+
     let ascii_zero = _mm_set1_epi8(b'0' as i8);
     let nines = _mm_set1_epi8(9);
     let ascii_a = _mm_set1_epi8((b'a' - 9 - 1) as i8);
@@ -129,7 +139,8 @@ unsafe fn hex_encode_sse41<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a
 
     let mut i = 0_usize;
     while src.len() >= 16 {
-        let invec = _mm_loadu_si128(src.as_ptr() as *const _);
+        // SAFETY: the loop condition ensures that we have at least 16 bytes
+        let invec = unsafe { _mm_loadu_si128(src.as_ptr() as *const _) };
 
         let masked1 = _mm_and_si128(invec, and4bits);
         let masked2 = _mm_and_si128(_mm_srli_epi64(invec, 4), and4bits);
@@ -146,20 +157,27 @@ unsafe fn hex_encode_sse41<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a
         let res1 = _mm_unpacklo_epi8(masked2, masked1);
         let res2 = _mm_unpackhi_epi8(masked2, masked1);
 
-        _mm_storeu_si128(dst.as_mut_ptr().add(i * 2) as *mut _, res1);
-        _mm_storeu_si128(dst.as_mut_ptr().add(i * 2 + 16) as *mut _, res2);
+        unsafe {
+            // SAFETY: the assertion at the beginning of the function ensures
+            // that `dst` is large enough.
+            _mm_storeu_si128(dst.as_mut_ptr().add(i * 2) as *mut _, res1);
+            _mm_storeu_si128(dst.as_mut_ptr().add(i * 2 + 16) as *mut _, res2);
+        }
         src = &src[16..];
         i += 16;
     }
 
     let _ = hex_encode_fallback(src, &mut dst[i * 2..]);
 
-    Ok(str::from_utf8_unchecked(&dst[..src.len() * 2 + i * 2]))
+    // SAFETY: `dst` only contains ASCII characters
+    unsafe { Ok(str::from_utf8_unchecked(&dst[..src.len() * 2 + i * 2])) }
 }
 
 #[cfg(target_arch = "wasm32")]
 #[target_feature(enable = "simd128")]
-unsafe fn hex_encode_simd128<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
+fn hex_encode_simd128<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
+    assert!(dst.len() >= src.len().checked_mul(2).unwrap());
+
     use core_arch::arch::wasm32::*;
 
     let ascii_zero = u8x16_splat(b'0');
@@ -169,7 +187,8 @@ unsafe fn hex_encode_simd128<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'
 
     let mut i = 0_usize;
     while src.len() >= 16 {
-        let invec = v128_load(src.as_ptr() as *const _);
+        // SAFETY: the loop condition ensures that we have at least 16 bytes
+        let invec = unsafe { v128_load(src.as_ptr() as *const _) };
 
         let masked1 = v128_and(invec, and4bits);
         let masked2 = v128_and(u8x16_shr(invec, 4), and4bits);
@@ -193,15 +212,20 @@ unsafe fn hex_encode_simd128<'a>(mut src: &[u8], dst: &'a mut [u8]) -> Result<&'
             masked2, masked1,
         );
 
-        v128_store(dst.as_mut_ptr().add(i * 2) as *mut _, res1);
-        v128_store(dst.as_mut_ptr().add(i * 2 + 16) as *mut _, res2);
+        unsafe {
+            // SAFETY: the assertion at the beginning of the function ensures
+            // that `dst` is large enough.
+            v128_store(dst.as_mut_ptr().add(i * 2) as *mut _, res1);
+            v128_store(dst.as_mut_ptr().add(i * 2 + 16) as *mut _, res2);
+        }
         src = &src[16..];
         i += 16;
     }
 
     let _ = hex_encode_fallback(src, &mut dst[i * 2..]);
 
-    Ok(str::from_utf8_unchecked(&dst[..src.len() * 2 + i * 2]))
+    // SAFETY: `dst` only contains ASCII characters
+    unsafe { Ok(str::from_utf8_unchecked(&dst[..src.len() * 2 + i * 2])) }
 }
 
 fn hex_encode_fallback<'a>(src: &[u8], dst: &'a mut [u8]) -> Result<&'a str, usize> {
diff --git a/library/stdarch/examples/wasm.rs b/library/stdarch/examples/wasm.rs
index 8ad38f3a031..ed313b15d1e 100644
--- a/library/stdarch/examples/wasm.rs
+++ b/library/stdarch/examples/wasm.rs
@@ -1,7 +1,6 @@
 //! A simple slab allocator for pages in wasm
 
 #![cfg(target_arch = "wasm32")]
-#![allow(unsafe_op_in_unsafe_fn)]
 
 use std::ptr;
 
@@ -11,11 +10,13 @@ static mut HEAD: *mut *mut u8 = 0 as _;
 
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn page_alloc() -> *mut u8 {
-    if !HEAD.is_null() {
-        let next = *HEAD;
-        let ret = HEAD;
-        HEAD = next as *mut _;
-        return ret as *mut u8;
+    unsafe {
+        if !HEAD.is_null() {
+            let next = *HEAD;
+            let ret = HEAD;
+            HEAD = next as *mut _;
+            return ret as *mut u8;
+        }
     }
 
     let ret = memory_grow(0, 1);
@@ -31,8 +32,10 @@ pub unsafe extern "C" fn page_alloc() -> *mut u8 {
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn page_free(page: *mut u8) {
     let page = page as *mut *mut u8;
-    *page = HEAD as *mut u8;
-    HEAD = page;
+    unsafe {
+        *page = HEAD as *mut u8;
+        HEAD = page;
+    }
 }
 
 #[unsafe(no_mangle)]