rename typed_swap → typed_swap_nonoverlapping

Author: RalfJung

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -75,7 +75,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // If we're swapping something that's *not* an `OperandValue::Ref`,
         // then we can do it directly and avoid the alloca.
         // Otherwise, we'll let the fallback MIR body take care of it.
-        if let sym::typed_swap = name {
+        if let sym::typed_swap_nonoverlapping = name {
             let pointee_ty = fn_args.type_at(0);
             let pointee_layout = bx.layout_of(pointee_ty);
             if !bx.is_backend_ref(pointee_layout)

compiler/rustc_codegen_ssa/src/traits/builder.rs

@@ -382,7 +382,7 @@ pub trait BuilderMethods<'a, 'tcx>:
     /// Avoids `alloca`s for Immediates and ScalarPairs.
     ///
     /// FIXME: Maybe do something smarter for Ref types too?
-    /// For now, the `typed_swap` intrinsic just doesn't call this for those
+    /// For now, the `typed_swap_nonoverlapping` intrinsic just doesn't call this for those
     /// cases (in non-debug), preferring the fallback body instead.
     fn typed_place_swap(
         &mut self,

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -424,7 +424,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let result = self.raw_eq_intrinsic(&args[0], &args[1])?;
                 self.write_scalar(result, dest)?;
             }
-            sym::typed_swap => {
+            sym::typed_swap_nonoverlapping => {
                 self.typed_swap_intrinsic(&args[0], &args[1])?;
             }
 

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -496,7 +496,9 @@ pub fn check_intrinsic_type(
                 (1, 0, vec![Ty::new_mut_ptr(tcx, param(0)), param(0)], tcx.types.unit)
             }
 
-            sym::typed_swap => (1, 0, vec![Ty::new_mut_ptr(tcx, param(0)); 2], tcx.types.unit),
+            sym::typed_swap_nonoverlapping => {
+                (1, 0, vec![Ty::new_mut_ptr(tcx, param(0)); 2], tcx.types.unit)
+            }
 
             sym::discriminant_value => {
                 let assoc_items = tcx.associated_item_def_ids(

compiler/rustc_span/src/symbol.rs

@@ -2058,7 +2058,7 @@ symbols! {
         type_macros,
         type_name,
         type_privacy_lints,
-        typed_swap,
+        typed_swap_nonoverlapping,
         u128,
         u128_legacy_const_max,
         u128_legacy_const_min,

library/core/src/intrinsics/mod.rs

@@ -3956,12 +3956,39 @@ pub const fn is_val_statically_known<T: Copy>(_arg: T) -> bool {
 // Const-unstable because `swap_nonoverlapping` is const-unstable.
 #[rustc_intrinsic_const_stable_indirect]
 #[rustc_allow_const_fn_unstable(const_swap_nonoverlapping)] // this is anyway not called since CTFE implements the intrinsic
+#[cfg(bootstrap)]
 pub const unsafe fn typed_swap<T>(x: *mut T, y: *mut T) {
     // SAFETY: The caller provided single non-overlapping items behind
     // pointers, so swapping them with `count: 1` is fine.
     unsafe { ptr::swap_nonoverlapping(x, y, 1) };
 }
 
+#[cfg(bootstrap)]
+pub use typed_swap as typed_swap_nonoverlapping;
+
+/// Non-overlapping *typed* swap of a single value.
+///
+/// The codegen backends will replace this with a better implementation when
+/// `T` is a simple type that can be loaded and stored as an immediate.
+///
+/// The stabilized form of this intrinsic is [`crate::mem::swap`].
+///
+/// # Safety
+///
+/// `x` and `y` are readable and writable as `T`, and non-overlapping.
+#[rustc_nounwind]
+#[inline]
+#[rustc_intrinsic]
+// Const-unstable because `swap_nonoverlapping` is const-unstable.
+#[rustc_intrinsic_const_stable_indirect]
+#[rustc_allow_const_fn_unstable(const_swap_nonoverlapping)] // this is anyway not called since CTFE implements the intrinsic
+#[cfg(not(bootstrap))]
+pub const unsafe fn typed_swap_nonoverlapping<T>(x: *mut T, y: *mut T) {
+    // SAFETY: The caller provided single non-overlapping items behind
+    // pointers, so swapping them with `count: 1` is fine.
+    unsafe { ptr::swap_nonoverlapping(x, y, 1) };
+}
+
 /// Returns whether we should perform some UB-checking at runtime. This eventually evaluates to
 /// `cfg!(ub_checks)`, but behaves different from `cfg!` when mixing crates built with different
 /// flags: if the crate has UB checks enabled or carries the `#[rustc_preserve_ub_checks]`

library/core/src/mem/mod.rs

@@ -730,7 +730,7 @@ pub unsafe fn uninitialized<T>() -> T {
 pub const fn swap<T>(x: &mut T, y: &mut T) {
     // SAFETY: `&mut` guarantees these are typed readable and writable
     // as well as non-overlapping.
-    unsafe { intrinsics::typed_swap(x, y) }
+    unsafe { intrinsics::typed_swap_nonoverlapping(x, y) }
 }
 
 /// Replaces `dest` with the default value of `T`, returning the previous `dest` value.

src/tools/miri/tests/fail/intrinsics/typed-swap-invalid-array.rs

@@ -1,7 +1,7 @@
 #![feature(core_intrinsics)]
 #![feature(rustc_attrs)]
 
-use std::intrinsics::typed_swap;
+use std::intrinsics::typed_swap_nonoverlapping;
 use std::ptr::addr_of_mut;
 
 fn invalid_array() {
@@ -10,7 +10,7 @@ fn invalid_array() {
     unsafe {
         let a = addr_of_mut!(a).cast::<[bool; 100]>();
         let b = addr_of_mut!(b).cast::<[bool; 100]>();
-        typed_swap(a, b); //~ERROR: constructing invalid value
+        typed_swap_nonoverlapping(a, b); //~ERROR: constructing invalid value
     }
 }
 

src/tools/miri/tests/fail/intrinsics/typed-swap-invalid-array.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: constructing invalid value at [0]: encountered 0x02, but expected a boolean
   --> tests/fail/intrinsics/typed-swap-invalid-array.rs:LL:CC
    |
-LL |         typed_swap(a, b);
-   |         ^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered 0x02, but expected a boolean
+LL |         typed_swap_nonoverlapping(a, b);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered 0x02, but expected a boolean
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail/intrinsics/typed-swap-invalid-scalar.rs

@@ -1,7 +1,7 @@
 #![feature(core_intrinsics)]
 #![feature(rustc_attrs)]
 
-use std::intrinsics::typed_swap;
+use std::intrinsics::typed_swap_nonoverlapping;
 use std::ptr::addr_of_mut;
 
 fn invalid_scalar() {
@@ -10,7 +10,7 @@ fn invalid_scalar() {
     unsafe {
         let a = addr_of_mut!(a).cast::<bool>();
         let b = addr_of_mut!(b).cast::<bool>();
-        typed_swap(a, b); //~ERROR: constructing invalid value
+        typed_swap_nonoverlapping(a, b); //~ERROR: constructing invalid value
     }
 }