Merge from rustc

Author: The Miri Cronjob Bot

Cargo.lock

@@ -50,3 +50,4 @@ rustc-demangle.opt-level = "s"
 rustc-std-workspace-core = { path = 'rustc-std-workspace-core' }
 rustc-std-workspace-alloc = { path = 'rustc-std-workspace-alloc' }
 rustc-std-workspace-std = { path = 'rustc-std-workspace-std' }
+compiler_builtins = { path = "compiler-builtins/compiler-builtins" }

Cargo.toml

@@ -16,7 +16,7 @@ bench = false
 
 [dependencies]
 core = { path = "../core", public = true }
-compiler_builtins = { version = "=0.1.160", features = ['rustc-dep-of-std'] }
+compiler_builtins = { path = "../compiler-builtins/compiler-builtins", features = ["rustc-dep-of-std"] }
 
 [features]
 compiler-builtins-mem = ['compiler_builtins/mem']

alloc/Cargo.toml

@@ -131,7 +131,6 @@
 #![feature(local_waker)]
 #![feature(maybe_uninit_slice)]
 #![feature(maybe_uninit_uninit_array_transpose)]
-#![feature(nonnull_provenance)]
 #![feature(panic_internals)]
 #![feature(pattern)]
 #![feature(pin_coerce_unsized_trait)]

alloc/src/lib.rs

@@ -28,7 +28,6 @@
 #![feature(iter_next_chunk)]
 #![feature(maybe_uninit_slice)]
 #![feature(maybe_uninit_uninit_array_transpose)]
-#![feature(nonnull_provenance)]
 #![feature(ptr_alignment_type)]
 #![feature(ptr_internals)]
 #![feature(sized_type_properties)]

alloctests/lib.rs

@@ -17,9 +17,7 @@ doctest = false
 test = false
 
 [dependencies]
-# For more information on this dependency see
-# https://github.com/rust-lang/rust/tree/master/library/rustc-std-workspace-core
-core = { version = "1.0.1", optional = true, package = "rustc-std-workspace-core" }
+core = { path = "../../core", optional = true }
 
 [build-dependencies]
 cc = { optional = true, version = "1.2" }

compiler-builtins/compiler-builtins/Cargo.toml

@@ -22,6 +22,9 @@ fn main() {
 
     println!("cargo:compiler-rt={}", cwd.join("compiler-rt").display());
 
+    println!("cargo::rustc-check-cfg=cfg(kernel_user_helpers)");
+    println!("cargo::rustc-check-cfg=cfg(feature, values(\"mem-unaligned\"))");
+
     // Emscripten's runtime includes all the builtins
     if target.os == "emscripten" {
         return;
@@ -47,7 +50,6 @@ fn main() {
     }
 
     // These targets have hardware unaligned access support.
-    println!("cargo::rustc-check-cfg=cfg(feature, values(\"mem-unaligned\"))");
     if target.arch.contains("x86_64")
         || target.arch.contains("x86")
         || target.arch.contains("aarch64")
@@ -78,7 +80,6 @@ fn main() {
     // Only emit the ARM Linux atomic emulation on pre-ARMv6 architectures. This
     // includes the old androideabi. It is deprecated but it is available as a
     // rustc target (arm-linux-androideabi).
-    println!("cargo::rustc-check-cfg=cfg(kernel_user_helpers)");
     if llvm_target[0] == "armv4t"
         || llvm_target[0] == "armv5te"
         || target.triple == "arm-linux-androideabi"

compiler-builtins/compiler-builtins/build.rs

@@ -4,7 +4,7 @@
 //! To avoid breaking backwards compat, C toolchains introduced a concept of "outlined atomics",
 //! where atomic operations call into the compiler runtime to dispatch between two depending on
 //! which is supported on the current CPU.
-//! See https://community.arm.com/arm-community-blogs/b/tools-software-ides-blog/posts/making-the-most-of-the-arm-architecture-in-gcc-10#:~:text=out%20of%20line%20atomics for more discussion.
+//! See <https://community.arm.com/arm-community-blogs/b/tools-software-ides-blog/posts/making-the-most-of-the-arm-architecture-in-gcc-10#:~:text=out%20of%20line%20atomics> for more discussion.
 //!
 //! Currently we only support LL/SC, because LSE requires `getauxval` from libc in order to do runtime detection.
 //! Use the `compiler-rt` intrinsics if you want LSE support.

compiler-builtins/compiler-builtins/src/aarch64_linux.rs

@@ -4,12 +4,17 @@ use core::{arch, mem};
 // Kernel-provided user-mode helper functions:
 // https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt
 unsafe fn __kuser_cmpxchg(oldval: u32, newval: u32, ptr: *mut u32) -> bool {
-    let f: extern "C" fn(u32, u32, *mut u32) -> u32 = mem::transmute(0xffff0fc0usize as *const ());
+    // FIXME(volatile): the third parameter is a volatile pointer
+    // SAFETY: kernel docs specify a known address with the given signature
+    let f = unsafe {
+        mem::transmute::<_, extern "C" fn(u32, u32, *mut u32) -> u32>(0xffff0fc0usize as *const ())
+    };
     f(oldval, newval, ptr) == 0
 }
 
 unsafe fn __kuser_memory_barrier() {
-    let f: extern "C" fn() = mem::transmute(0xffff0fa0usize as *const ());
+    // SAFETY: kernel docs specify a known address with the given signature
+    let f = unsafe { mem::transmute::<_, extern "C" fn()>(0xffff0fa0usize as *const ()) };
     f();
 }
 
@@ -67,8 +72,10 @@ fn insert_aligned(aligned: u32, val: u32, shift: u32, mask: u32) -> u32 {
 /// - if `size_of::<T>() == 2`, `ptr` or `ptr` offset by 2 bytes must be valid for a relaxed atomic
 ///   read of 2 bytes.
 /// - if `size_of::<T>() == 4`, `ptr` must be valid for a relaxed atomic read of 4 bytes.
+// FIXME: assert some of the preconditions in debug mode
 unsafe fn atomic_load_aligned<T>(ptr: *mut u32) -> u32 {
-    if mem::size_of::<T>() == 4 {
+    const { assert!(size_of::<T>() <= 4) };
+    if size_of::<T>() == 4 {
         // SAFETY: As `T` has a size of 4, the caller garantees this is sound.
         unsafe { AtomicU32::from_ptr(ptr).load(Ordering::Relaxed) }
     } else {
@@ -100,11 +107,13 @@ unsafe fn atomic_rmw<T, F: Fn(u32) -> u32, G: Fn(u32, u32) -> u32>(ptr: *mut T,
     let (shift, mask) = get_shift_mask(ptr);
 
     loop {
-        let curval_aligned = atomic_load_aligned::<T>(aligned_ptr);
+        // FIXME(safety): preconditions review needed
+        let curval_aligned = unsafe { atomic_load_aligned::<T>(aligned_ptr) };
         let curval = extract_aligned(curval_aligned, shift, mask);
         let newval = f(curval);
         let newval_aligned = insert_aligned(curval_aligned, newval, shift, mask);
-        if __kuser_cmpxchg(curval_aligned, newval_aligned, aligned_ptr) {
+        // FIXME(safety): preconditions review needed
+        if unsafe { __kuser_cmpxchg(curval_aligned, newval_aligned, aligned_ptr) } {
             return g(curval, newval);
         }
     }
@@ -116,13 +125,15 @@ unsafe fn atomic_cmpxchg<T>(ptr: *mut T, oldval: u32, newval: u32) -> u32 {
     let (shift, mask) = get_shift_mask(ptr);
 
     loop {
-        let curval_aligned = atomic_load_aligned::<T>(aligned_ptr);
+        // FIXME(safety): preconditions review needed
+        let curval_aligned = unsafe { atomic_load_aligned::<T>(aligned_ptr) };
         let curval = extract_aligned(curval_aligned, shift, mask);
         if curval != oldval {
             return curval;
         }
         let newval_aligned = insert_aligned(curval_aligned, newval, shift, mask);
-        if __kuser_cmpxchg(curval_aligned, newval_aligned, aligned_ptr) {
+        // FIXME(safety): preconditions review needed
+        if unsafe { __kuser_cmpxchg(curval_aligned, newval_aligned, aligned_ptr) } {
             return oldval;
         }
     }
@@ -132,7 +143,14 @@ macro_rules! atomic_rmw {
     ($name:ident, $ty:ty, $op:expr, $fetch:expr) => {
         intrinsics! {
             pub unsafe extern "C" fn $name(ptr: *mut $ty, val: $ty) -> $ty {
-                atomic_rmw(ptr, |x| $op(x as $ty, val) as u32, |old, new| $fetch(old, new)) as $ty
+                // FIXME(safety): preconditions review needed
+                unsafe {
+                    atomic_rmw(
+                        ptr,
+                        |x| $op(x as $ty, val) as u32,
+                        |old, new| $fetch(old, new)
+                    ) as $ty
+                }
             }
         }
     };
@@ -149,7 +167,8 @@ macro_rules! atomic_cmpxchg {
     ($name:ident, $ty:ty) => {
         intrinsics! {
             pub unsafe extern "C" fn $name(ptr: *mut $ty, oldval: $ty, newval: $ty) -> $ty {
-                atomic_cmpxchg(ptr, oldval as u32, newval as u32) as $ty
+                // FIXME(safety): preconditions review needed
+                unsafe { atomic_cmpxchg(ptr, oldval as u32, newval as u32) as $ty }
             }
         }
     };
@@ -285,6 +304,7 @@ atomic_cmpxchg!(__sync_val_compare_and_swap_4, u32);
 
 intrinsics! {
     pub unsafe extern "C" fn __sync_synchronize() {
-        __kuser_memory_barrier();
+       // SAFETY: preconditions are the same as the calling function.
+       unsafe {  __kuser_memory_barrier() };
     }
 }

compiler-builtins/compiler-builtins/src/arm_linux.rs

@@ -69,7 +69,7 @@ pub unsafe fn copy_backward(dest: *mut u8, src: *const u8, count: usize) {
         "rep movsb",
         "sub $7, %rsi",
         "sub $7, %rdi",
-        "mov {qword_count}, %rcx",
+        "mov {qword_count:r}, %rcx",
         "rep movsq",
         "test {pre_byte_count:e}, {pre_byte_count:e}",
         "add $7, %rsi",
@@ -212,7 +212,7 @@ pub unsafe fn c_string_length(mut s: *const core::ffi::c_char) -> usize {
     let x = {
         let r;
         asm!(
-            "movdqa ({addr}), {dest}",
+            "movdqa ({addr:r}), {dest}",
             addr = in(reg) s,
             dest = out(xmm_reg) r,
             options(att_syntax, nostack),
@@ -232,7 +232,7 @@ pub unsafe fn c_string_length(mut s: *const core::ffi::c_char) -> usize {
         let x = {
             let r;
             asm!(
-                "movdqa ({addr}), {dest}",
+                "movdqa ({addr:r}), {dest}",
                 addr = in(reg) s,
                 dest = out(xmm_reg) r,
                 options(att_syntax, nostack),

compiler-builtins/compiler-builtins/src/mem/x86_64.rs

@@ -29,6 +29,8 @@ debug_typeid = []
 [lints.rust.unexpected_cfgs]
 level = "warn"
 check-cfg = [
+    # #[cfg(bootstrap)] loongarch32
+    'cfg(target_arch, values("loongarch32"))',
     'cfg(no_fp_fmt_parse)',
     # core use #[path] imports to portable-simd `core_simd` crate
     # and to stdarch `core_arch` crate which messes-up with Cargo list

core/Cargo.toml

@@ -1914,6 +1914,8 @@ impl<T: ?Sized + fmt::Display> fmt::Display for RefMut<'_, T> {
 /// [`.get()`]: `UnsafeCell::get`
 /// [concurrent memory model]: ../sync/atomic/index.html#memory-model-for-atomic-accesses
 ///
+/// # Aliasing rules
+///
 /// The precise Rust aliasing rules are somewhat in flux, but the main points are not contentious:
 ///
 /// - If you create a safe reference with lifetime `'a` (either a `&T` or `&mut T` reference), then
@@ -2167,10 +2169,9 @@ impl<T: ?Sized> UnsafeCell<T> {
 
     /// Gets a mutable pointer to the wrapped value.
     ///
-    /// This can be cast to a pointer of any kind.
-    /// Ensure that the access is unique (no active references, mutable or not)
-    /// when casting to `&mut T`, and ensure that there are no mutations
-    /// or mutable aliases going on when casting to `&T`
+    /// This can be cast to a pointer of any kind. When creating references, you must uphold the
+    /// aliasing rules; see [the type-level docs][UnsafeCell#aliasing-rules] for more discussion and
+    /// caveats.
     ///
     /// # Examples
     ///
@@ -2219,10 +2220,9 @@ impl<T: ?Sized> UnsafeCell<T> {
     /// The difference from [`get`] is that this function accepts a raw pointer,
     /// which is useful to avoid the creation of temporary references.
     ///
-    /// The result can be cast to a pointer of any kind.
-    /// Ensure that the access is unique (no active references, mutable or not)
-    /// when casting to `&mut T`, and ensure that there are no mutations
-    /// or mutable aliases going on when casting to `&T`.
+    /// This can be cast to a pointer of any kind. When creating references, you must uphold the
+    /// aliasing rules; see [the type-level docs][UnsafeCell#aliasing-rules] for more discussion and
+    /// caveats.
     ///
     /// [`get`]: UnsafeCell::get()
     ///

core/src/cell.rs

@@ -2651,15 +2651,6 @@ pub const fn size_of<T>() -> usize;
 #[rustc_intrinsic]
 pub const fn min_align_of<T>() -> usize;
 
-/// The preferred alignment of a type.
-///
-/// This intrinsic does not have a stable counterpart.
-/// It's "tracking issue" is [#91971](https://github.com/rust-lang/rust/issues/91971).
-#[rustc_nounwind]
-#[unstable(feature = "core_intrinsics", issue = "none")]
-#[rustc_intrinsic]
-pub const unsafe fn pref_align_of<T>() -> usize;
-
 /// Returns the number of variants of the type `T` cast to a `usize`;
 /// if `T` has no variants, returns `0`. Uninhabited variants will be counted.
 ///

core/src/intrinsics/mod.rs

@@ -20,7 +20,7 @@
 /// ```
 #[unstable(feature = "iter_macro", issue = "none", reason = "generators are unstable")]
 #[allow_internal_unstable(coroutines, iter_from_coroutine)]
-#[cfg_attr(not(bootstrap), rustc_builtin_macro)]
+#[rustc_builtin_macro]
 pub macro iter($($t:tt)*) {
     /* compiler-builtin */
 }

core/src/iter/sources/generator.rs

@@ -197,7 +197,6 @@
 #![feature(riscv_target_feature)]
 #![feature(rtm_target_feature)]
 #![feature(s390x_target_feature)]
-#![feature(sha512_sm_x86)]
 #![feature(sse4a_target_feature)]
 #![feature(tbm_target_feature)]
 #![feature(wasm_target_feature)]