Use slice::from_ref and slice::from_mut

cranelift/codegen/meta/src/gen_inst.rs

@@ -97,9 +97,14 @@ fn gen_instruction_data(registry: &FormatRegistry, fmt: &mut Formatter) {
 
 fn gen_arguments_method(registry: &FormatRegistry, fmt: &mut Formatter, is_mut: bool) {
     let (method, mut_, rslice, as_slice) = if is_mut {
-        ("arguments_mut", "mut ", "ref_slice_mut", "as_mut_slice")
+        (
+            "arguments_mut",
+            "mut ",
+            "core::slice::from_mut",
+            "as_mut_slice",
+        )
     } else {
-        ("arguments", "", "ref_slice", "as_slice")
+        ("arguments", "", "core::slice::from_ref", "as_slice")
     };
 
     fmtln!(

cranelift/codegen/src/ir/instructions.rs

@@ -18,7 +18,6 @@ use crate::isa;
 
 use crate::bitset::BitSet;
 use crate::entity;
-use crate::ref_slice::{ref_slice, ref_slice_mut};
 
 /// Some instructions use an external list of argument values because there is not enough space in
 /// the 16-byte `InstructionData` struct. These value lists are stored in a memory pool in

cranelift/codegen/src/lib.rs

@@ -95,7 +95,6 @@ mod partition_slice;
 mod postopt;
 mod predicates;
 mod redundant_reload_remover;
-mod ref_slice;
 mod regalloc;
 mod result;
 mod scoped_hash_map;

cranelift/codegen/src/ref_slice.rs

@@ -1,18 +0,0 @@
-//! Functions for converting a reference into a singleton slice.
-//!
-//! See also the [`ref_slice` crate](https://crates.io/crates/ref_slice).
-//!
-//! We define the functions here to avoid external dependencies, and to ensure that they are
-//! inlined in this crate.
-//!
-//! Despite their using an unsafe block, these functions are completely safe.
-
-use core::slice;
-
-pub fn ref_slice<T>(s: &T) -> &[T] {
-    unsafe { slice::from_raw_parts(s, 1) }
-}
-
-pub fn ref_slice_mut<T>(s: &mut T) -> &mut [T] {
-    unsafe { slice::from_raw_parts_mut(s, 1) }
-}

cranelift/codegen/src/regalloc/virtregs.rs

@@ -18,9 +18,9 @@ use crate::entity::{EntityList, ListPool};
 use crate::entity::{Keys, PrimaryMap, SecondaryMap};
 use crate::ir::{Function, Value};
 use crate::packed_option::PackedOption;
-use crate::ref_slice::ref_slice;
 use core::cmp::Ordering;
 use core::fmt;
+use core::slice;
 use smallvec::SmallVec;
 use std::vec::Vec;
 
@@ -104,7 +104,7 @@ impl VirtRegs {
         'a: 'b,
     {
         self.get(*value)
-            .map_or_else(|| ref_slice(value), |vr| self.values(vr))
+            .map_or_else(|| slice::from_ref(value), |vr| self.values(vr))
     }
 
     /// Check if `a` and `b` belong to the same congruence class.