Rollup of 10 pull requests

compiler/rustc_codegen_llvm/src/common.rs

@@ -109,8 +109,7 @@ impl<'ll> CodegenCx<'ll, '_> {
     pub fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value {
         unsafe {
             assert_eq!(idx as c_uint as u64, idx);
-            let us = &[idx as c_uint];
-            let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
+            let r = llvm::LLVMGetAggregateElement(v, idx as c_uint).unwrap();
 
             debug!("const_get_elt(v={:?}, idx={}, r={:?})", v, idx, r);
 

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1134,11 +1134,7 @@ extern "C" {
     pub fn LLVMConstIntToPtr<'a>(ConstantVal: &'a Value, ToType: &'a Type) -> &'a Value;
     pub fn LLVMConstBitCast<'a>(ConstantVal: &'a Value, ToType: &'a Type) -> &'a Value;
     pub fn LLVMConstPointerCast<'a>(ConstantVal: &'a Value, ToType: &'a Type) -> &'a Value;
-    pub fn LLVMConstExtractValue(
-        AggConstant: &Value,
-        IdxList: *const c_uint,
-        NumIdx: c_uint,
-    ) -> &Value;
+    pub fn LLVMGetAggregateElement(ConstantVal: &Value, Idx: c_uint) -> Option<&Value>;
 
     // Operations on global variables, functions, and aliases (globals)
     pub fn LLVMIsDeclaration(Global: &Value) -> Bool;

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -346,7 +346,7 @@ fn valtree_into_mplace<'tcx>(
         ty::FnDef(_, _) => {
             ecx.write_immediate(
                 Immediate::Scalar(ScalarMaybeUninit::Scalar(Scalar::ZST)),
-                &(*place).into(),
+                &place.into(),
             )
             .unwrap();
         }
@@ -355,7 +355,7 @@ fn valtree_into_mplace<'tcx>(
             debug!("writing trivial valtree {:?} to place {:?}", scalar_int, place);
             ecx.write_immediate(
                 Immediate::Scalar(ScalarMaybeUninit::Scalar(scalar_int.into())),
-                &(*place).into(),
+                &place.into(),
             )
             .unwrap();
         }
@@ -382,7 +382,7 @@ fn valtree_into_mplace<'tcx>(
             };
             debug!(?imm);
 
-            ecx.write_immediate(imm, &(*place).into()).unwrap();
+            ecx.write_immediate(imm, &place.into()).unwrap();
         }
         ty::Adt(_, _) | ty::Tuple(_) | ty::Array(_, _) | ty::Str | ty::Slice(_) => {
             let branches = valtree.unwrap_branch();
@@ -464,11 +464,11 @@ fn valtree_into_mplace<'tcx>(
 
             if let Some(variant_idx) = variant_idx {
                 // don't forget filling the place with the discriminant of the enum
-                ecx.write_discriminant(variant_idx, &(*place).into()).unwrap();
+                ecx.write_discriminant(variant_idx, &place.into()).unwrap();
             }
 
             debug!("dump of place after writing discriminant:");
-            dump_place(ecx, (*place).into());
+            dump_place(ecx, place.into());
         }
         _ => bug!("shouldn't have created a ValTree for {:?}", ty),
     }

compiler/rustc_const_eval/src/interpret/intern.rs

@@ -195,7 +195,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: CompileTimeMachine<'mir, 'tcx, const_eval::Memory
         let tcx = self.ecx.tcx;
         let ty = mplace.layout.ty;
         if let ty::Ref(_, referenced_ty, ref_mutability) = *ty.kind() {
-            let value = self.ecx.read_immediate(&(*mplace).into())?;
+            let value = self.ecx.read_immediate(&mplace.into())?;
             let mplace = self.ecx.ref_to_mplace(&value)?;
             assert_eq!(mplace.layout.ty, referenced_ty);
             // Handle trait object vtables.

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -204,6 +204,13 @@ impl<'tcx, Tag: Provenance> From<&'_ MPlaceTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
     }
 }
 
+impl<'tcx, Tag: Provenance> From<&'_ mut MPlaceTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
+    #[inline(always)]
+    fn from(mplace: &mut MPlaceTy<'tcx, Tag>) -> Self {
+        OpTy { op: Operand::Indirect(**mplace), layout: mplace.layout }
+    }
+}
+
 impl<'tcx, Tag: Provenance> From<ImmTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
     #[inline(always)]
     fn from(val: ImmTy<'tcx, Tag>) -> Self {

compiler/rustc_const_eval/src/interpret/place.rs

@@ -118,7 +118,21 @@ impl<'tcx, Tag: Provenance> std::ops::Deref for MPlaceTy<'tcx, Tag> {
 impl<'tcx, Tag: Provenance> From<MPlaceTy<'tcx, Tag>> for PlaceTy<'tcx, Tag> {
     #[inline(always)]
     fn from(mplace: MPlaceTy<'tcx, Tag>) -> Self {
-        PlaceTy { place: Place::Ptr(mplace.mplace), layout: mplace.layout }
+        PlaceTy { place: Place::Ptr(*mplace), layout: mplace.layout }
+    }
+}
+
+impl<'tcx, Tag: Provenance> From<&'_ MPlaceTy<'tcx, Tag>> for PlaceTy<'tcx, Tag> {
+    #[inline(always)]
+    fn from(mplace: &MPlaceTy<'tcx, Tag>) -> Self {
+        PlaceTy { place: Place::Ptr(**mplace), layout: mplace.layout }
+    }
+}
+
+impl<'tcx, Tag: Provenance> From<&'_ mut MPlaceTy<'tcx, Tag>> for PlaceTy<'tcx, Tag> {
+    #[inline(always)]
+    fn from(mplace: &mut MPlaceTy<'tcx, Tag>) -> Self {
+        PlaceTy { place: Place::Ptr(**mplace), layout: mplace.layout }
     }
 }
 

compiler/rustc_const_eval/src/interpret/visitor.rs

@@ -92,7 +92,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> Value<'mir, 'tcx, M>
         &self,
         _ecx: &InterpCx<'mir, 'tcx, M>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
-        Ok((*self).into())
+        Ok(self.into())
     }
 
     #[inline(always)]

compiler/rustc_errors/src/lib.rs

@@ -1447,7 +1447,7 @@ impl HandlerInner {
                 self.flags.treat_err_as_bug.map(|c| c.get()).unwrap_or(0),
             ) {
                 (1, 1) => panic!("aborting due to `-Z treat-err-as-bug=1`"),
-                (0, _) | (1, _) => {}
+                (0 | 1, _) => {}
                 (count, as_bug) => panic!(
                     "aborting after {} errors due to `-Z treat-err-as-bug={}`",
                     count, as_bug,

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1865,3 +1865,11 @@ extern "C" void LLVMRustGetMangledName(LLVMValueRef V, RustStringRef Str) {
   GlobalValue *GV = unwrap<GlobalValue>(V);
   Mangler().getNameWithPrefix(OS, GV, true);
 }
+
+// LLVMGetAggregateElement was added in LLVM 15. For earlier LLVM versions just
+// use its implementation.
+#if LLVM_VERSION_LT(15, 0)
+extern "C" LLVMValueRef LLVMGetAggregateElement(LLVMValueRef C, unsigned Idx) {
+    return wrap(unwrap<Constant>(C)->getAggregateElement(Idx));
+}
+#endif

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1503,6 +1503,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         Some(match name {
             "byte" => sym::u8, // In Java, bytes are signed, but in practice one almost always wants unsigned bytes.
             "short" => sym::i16,
+            "Bool" => sym::bool,
+            "Boolean" => sym::bool,
             "boolean" => sym::bool,
             "int" => sym::i32,
             "long" => sym::i64,

library/core/src/sync/exclusive.rs

@@ -0,0 +1,173 @@
+//! Defines [`Exclusive`].
+
+use core::fmt;
+use core::future::Future;
+use core::pin::Pin;
+use core::task::{Context, Poll};
+
+/// `Exclusive` provides only _mutable_ access, also referred to as _exclusive_
+/// access to the underlying value. It provides no _immutable_, or _shared_
+/// access to the underlying value.
+///
+/// While this may seem not very useful, it allows `Exclusive` to _unconditionally_
+/// implement [`Sync`]. Indeed, the safety requirements of `Sync` state that for `Exclusive`
+/// to be `Sync`, it must be sound to _share_ across threads, that is, it must be sound
+/// for `&Exclusive` to cross thread boundaries. By design, a `&Exclusive` has no API
+/// whatsoever, making it useless, thus harmless, thus memory safe.
+///
+/// Certain constructs like [`Future`]s can only be used with _exclusive_ access,
+/// and are often `Send` but not `Sync`, so `Exclusive` can be used as hint to the
+/// rust compiler that something is `Sync` in practice.
+///
+/// ## Examples
+/// Using a non-`Sync` future prevents the wrapping struct from being `Sync`
+/// ```compile_fail
+/// use core::cell::Cell;
+///
+/// async fn other() {}
+/// fn assert_sync<T: Sync>(t: T) {}
+/// struct State<F> {
+///     future: F
+/// }
+///
+/// assert_sync(State {
+///     future: async {
+///         let cell = Cell::new(1);
+///         let cell_ref = &cell;
+///         other().await;
+///         let value = cell_ref.get();
+///     }
+/// });
+/// ```
+///
+/// `Exclusive` ensures the struct is `Sync` without stripping the future of its
+/// functionality.
+/// ```
+/// #![feature(exclusive_wrapper)]
+/// use core::cell::Cell;
+/// use core::sync::Exclusive;
+///
+/// async fn other() {}
+/// fn assert_sync<T: Sync>(t: T) {}
+/// struct State<F> {
+///     future: Exclusive<F>
+/// }
+///
+/// assert_sync(State {
+///     future: Exclusive::new(async {
+///         let cell = Cell::new(1);
+///         let cell_ref = &cell;
+///         other().await;
+///         let value = cell_ref.get();
+///     })
+/// });
+/// ```
+///
+/// ## Parallels with a mutex
+/// In some sense, `Exclusive` can be thought of as a _compile-time_ version of
+/// a mutex, as the borrow-checker guarantees that only one `&mut` can exist
+/// for any value. This is a parallel with the fact that
+/// `&` and `&mut` references together can be thought of as a _compile-time_
+/// version of a read-write lock.
+///
+///
+/// [`Sync`]: core::marker::Sync
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+#[doc(alias = "SyncWrapper")]
+#[doc(alias = "SyncCell")]
+#[doc(alias = "Unique")]
+// `Exclusive` can't have `PartialOrd`, `Clone`, etc. impls as they would
+// use `&` access to the inner value, violating the `Sync` impl's safety
+// requirements.
+#[derive(Default)]
+#[repr(transparent)]
+pub struct Exclusive<T: ?Sized> {
+    inner: T,
+}
+
+// See `Exclusive`'s docs for justification.
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+unsafe impl<T: ?Sized> Sync for Exclusive<T> {}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T: ?Sized> fmt::Debug for Exclusive<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        f.debug_struct("Exclusive").finish_non_exhaustive()
+    }
+}
+
+impl<T: Sized> Exclusive<T> {
+    /// Wrap a value in an `Exclusive`
+    #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+    #[must_use]
+    pub const fn new(t: T) -> Self {
+        Self { inner: t }
+    }
+
+    /// Unwrap the value contained in the `Exclusive`
+    #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+    #[must_use]
+    pub const fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+impl<T: ?Sized> Exclusive<T> {
+    /// Get exclusive access to the underlying value.
+    #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+    #[must_use]
+    pub const fn get_mut(&mut self) -> &mut T {
+        &mut self.inner
+    }
+
+    /// Get pinned exclusive access to the underlying value.
+    ///
+    /// `Exclusive` is considered to _structurally pin_ the underlying
+    /// value, which means _unpinned_ `Exclusive`s can produce _unpinned_
+    /// access to the underlying value, but _pinned_ `Exclusive`s only
+    /// produce _pinned_ access to the underlying value.
+    #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+    #[must_use]
+    pub const fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
+        // SAFETY: `Exclusive` can only produce `&mut T` if itself is unpinned
+        // `Pin::map_unchecked_mut` is not const, so we do this conversion manually
+        unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().inner) }
+    }
+
+    /// Build a _mutable_ references to an `Exclusive<T>` from
+    /// a _mutable_ reference to a `T`. This allows you to skip
+    /// building an `Exclusive` with [`Exclusive::new`].
+    #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+    #[must_use]
+    pub const fn from_mut(r: &'_ mut T) -> &'_ mut Exclusive<T> {
+        // SAFETY: repr is ≥ C, so refs have the same layout; and `Exclusive` properties are `&mut`-agnostic
+        unsafe { &mut *(r as *mut T as *mut Exclusive<T>) }
+    }
+
+    /// Build a _pinned mutable_ references to an `Exclusive<T>` from
+    /// a _pinned mutable_ reference to a `T`. This allows you to skip
+    /// building an `Exclusive` with [`Exclusive::new`].
+    #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+    #[must_use]
+    pub const fn from_pin_mut(r: Pin<&'_ mut T>) -> Pin<&'_ mut Exclusive<T>> {
+        // SAFETY: `Exclusive` can only produce `&mut T` if itself is unpinned
+        // `Pin::map_unchecked_mut` is not const, so we do this conversion manually
+        unsafe { Pin::new_unchecked(Self::from_mut(r.get_unchecked_mut())) }
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> From<T> for Exclusive<T> {
+    fn from(t: T) -> Self {
+        Self::new(t)
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T: Future + ?Sized> Future for Exclusive<T> {
+    type Output = T::Output;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.get_pin_mut().poll(cx)
+    }
+}

library/core/src/sync/mod.rs

@@ -3,3 +3,6 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 pub mod atomic;
+mod exclusive;
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+pub use exclusive::Exclusive;

library/std/src/lib.rs

@@ -270,6 +270,7 @@
 #![feature(duration_checked_float)]
 #![feature(duration_constants)]
 #![feature(exact_size_is_empty)]
+#![feature(exclusive_wrapper)]
 #![feature(extend_one)]
 #![feature(float_minimum_maximum)]
 #![feature(hasher_prefixfree_extras)]

library/std/src/sync/mod.rs

@@ -155,6 +155,8 @@
 pub use alloc_crate::sync::{Arc, Weak};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::sync::atomic;
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+pub use core::sync::Exclusive;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::barrier::{Barrier, BarrierWaitResult};