Auto merge of rust-lang#157228 - jhpratt:rollup-V1fPjTM, r=jhpratt

Rollup of 6 pull requests

Successful merges:

 - rust-lang#156832 (library: use strict provenance lints consistently)
 - rust-lang#157223 (rustdoc: Fix ICE on delegated async functions)
 - rust-lang#156528 (Explicitly request copying `rustc-dev` artifacts for rustfmt/clippy and add rustc libs path for rustc-private tools under `download-rustc`)
 - rust-lang#157059 (update TargetFeature::Forbidden docs)
 - rust-lang#157159 (Fix CI free-disk-space-linux script)
 - rust-lang#157221 (Help people looking for random bytes find `DefaultRandomSource.fill_bytes`)

Author: bors

compiler/rustc_target/src/target_features.rs

@@ -1,6 +1,44 @@
 //! Declares Rust's target feature names for each target.
 //! Note that these are similar to but not always identical to LLVM's feature names,
 //! and Rust adds some features that do not correspond to LLVM features at all.
+//!
+//! The target features listed here can be used in `#[target_feature]` and `#[cfg(target_feature)]`.
+//! They also do not trigger any warnings when used with `-Ctarget-feature`.
+//!
+//! Note that even unstable (and even entirely unlisted) features can be used with `-Ctarget-feature`
+//! on stable. Using a feature not on the list of Rust target features only emits a warning.
+//! Only `cfg(target_feature)` and `#[target_feature]` actually do any stability gating.
+//! `cfg(target_feature)` for unstable features just works on nightly without any feature gate.
+//! `#[target_feature]` requires a feature gate.
+//!
+//! When adding features to the below lists
+//! check whether they're named already elsewhere in rust
+//! e.g. in stdarch and whether the given name matches LLVM's
+//! if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted.
+//! Additionally, if the feature is not available in older version of LLVM supported by the current
+//! rust, the same function must be updated to filter out these features to avoid triggering
+//! warnings.
+//!
+//! Also note that all target features listed here must be purely additive: for target_feature 1.1 to
+//! be sound, we can never allow features like `+soft-float` (on x86) to be controlled on a
+//! per-function level, since we would then allow safe calls from functions with `+soft-float` to
+//! functions without that feature!
+//!
+//! It is important for soundness to consider the interaction of target features and the function
+//! call ABI. For example, disabling the `x87` feature on x86 changes how scalar floats are passed as
+//! arguments, so letting people toggle that feature would be unsound. To this end, the
+//! [`Target::abi_required_features`] function computes which target features must and must not be
+//! enabled for any given target, and individual features can also be marked as [`Forbidden`]. See
+//! <https://github.com/rust-lang/rust/issues/116344> for some more context.
+//!
+//! The one exception to features that change the ABI is features that enable larger vector
+//! registers. Those are permitted to be listed here. The `*_FOR_CORRECT_VECTOR_ABI` arrays store
+//! information about which target feature is ABI-required for which vector size; this is used to
+//! ensure that vectors can only be passed via `extern "C"` when the right feature is enabled. (For
+//! the "Rust" ABI we generally pass vectors by-ref exactly to avoid these issues.)
+//! Also see <https://github.com/rust-lang/rust/issues/116558>.
+//!
+//! Stabilizing a target feature requires t-lang approval.
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_macros::StableHash;
 use rustc_span::{Symbol, sym};
@@ -32,9 +70,12 @@ pub enum Stability {
         Symbol,
     ),
     /// This feature can not be set via `-Ctarget-feature` or `#[target_feature]`, it can only be
-    /// set in the target spec. It is never set in `cfg(target_feature)`. Used in
-    /// particular for features are actually ABI configuration flags (not all targets are as nice as
-    /// RISC-V and have an explicit way to set the ABI separate from target features).
+    /// set in the target spec. It is never set in `cfg(target_feature)`. Used in particular for
+    /// features are actually ABI configuration flags (such as "soft-float" on many targets).
+    /// However, "forbidden" target features can still sometimes be enabled via `-Ctarget-cpu` or
+    /// target feature implications (on the Rust/LLVM level). To prevent that, ABI-relevant target
+    /// features are ideally pinned down (required or forbidden) in
+    /// [`Target::abi_required_features`].
     Forbidden {
         reason: &'static str,
         /// True if this is always an error, false if this can be reported as a warning when set via
@@ -102,50 +143,11 @@ impl Stability {
     }
 }
 
-// Here we list target features that rustc "understands": they can be used in `#[target_feature]`
-// and `#[cfg(target_feature)]`. They also do not trigger any warnings when used with
-// `-Ctarget-feature`.
-//
-// Note that even unstable (and even entirely unlisted) features can be used with `-Ctarget-feature`
-// on stable. Using a feature not on the list of Rust target features only emits a warning.
-// Only `cfg(target_feature)` and `#[target_feature]` actually do any stability gating.
-// `cfg(target_feature)` for unstable features just works on nightly without any feature gate.
-// `#[target_feature]` requires a feature gate.
-//
-// When adding features to the below lists
-// check whether they're named already elsewhere in rust
-// e.g. in stdarch and whether the given name matches LLVM's
-// if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted.
-// Additionally, if the feature is not available in older version of LLVM supported by the current
-// rust, the same function must be updated to filter out these features to avoid triggering
-// warnings.
-//
-// Also note that all target features listed here must be purely additive: for target_feature 1.1 to
-// be sound, we can never allow features like `+soft-float` (on x86) to be controlled on a
-// per-function level, since we would then allow safe calls from functions with `+soft-float` to
-// functions without that feature!
-//
-// It is important for soundness to consider the interaction of targets features and the function
-// call ABI. For example, disabling the `x87` feature on x86 changes how scalar floats are passed as
-// arguments, so letting people toggle that feature would be unsound. To this end, the
-// `abi_required_features` function computes which target features must and must not be enabled for
-// any given target, and individual features can also be marked as `Forbidden`.
-// See https://github.com/rust-lang/rust/issues/116344 for some more context.
-//
-// The one exception to features that change the ABI is features that enable larger vector
-// registers. Those are permitted to be listed here. The `*_FOR_CORRECT_VECTOR_ABI` arrays store
-// information about which target feature is ABI-required for which vector size; this is used to
-// ensure that vectors can only be passed via `extern "C"` when the right feature is enabled. (For
-// the "Rust" ABI we generally pass vectors by-ref exactly to avoid these issues.)
-// Also see https://github.com/rust-lang/rust/issues/116558.
-//
-// Stabilizing a target feature requires t-lang approval.
-
-// If feature A "implies" feature B, then:
-// - when A gets enabled (via `-Ctarget-feature` or `#[target_feature]`), we also enable B
-// - when B gets disabled (via `-Ctarget-feature`), we also disable A
-//
-// Both of these are also applied transitively.
+/// If feature A "implies" feature B, then:
+/// - when A gets enabled (via `-Ctarget-feature` or `#[target_feature]`), we also enable B
+/// - when B gets disabled (via `-Ctarget-feature`), we also disable A
+///
+/// Both of these are also applied transitively.
 type ImpliedFeatures = &'static [&'static str];
 
 static ARM_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[

library/alloc/src/lib.rs

@@ -73,6 +73,7 @@
 // Lints:
 #![deny(unsafe_op_in_unsafe_fn)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 #![warn(deprecated_in_future)]
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]

library/alloctests/benches/lib.rs

@@ -7,6 +7,7 @@
 #![feature(strict_provenance_lints)]
 #![feature(test)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 
 extern crate test;
 

library/alloctests/tests/boxed.rs

@@ -47,9 +47,9 @@ fn box_clone_from_ptr_stability() {
     for size in (0..8).map(|i| 2usize.pow(i)) {
         let control = vec![Dummy { _data: 42 }; size].into_boxed_slice();
         let mut copy = vec![Dummy { _data: 84 }; size].into_boxed_slice();
-        let copy_raw = copy.as_ptr() as usize;
+        let copy_raw = copy.as_ptr();
         copy.clone_from(&control);
-        assert_eq!(copy.as_ptr() as usize, copy_raw);
+        assert_eq!(copy.as_ptr(), copy_raw);
     }
 }
 

library/alloctests/tests/heap.rs

@@ -25,7 +25,7 @@ fn check_overalign_requests<T: Allocator>(allocator: T) {
                     .collect();
                 for &ptr in &pointers {
                     assert_eq!(
-                        (ptr.as_non_null_ptr().as_ptr() as usize) % align,
+                        ptr.as_non_null_ptr().as_ptr().addr() % align,
                         0,
                         "Got a pointer less aligned than requested"
                     )

library/alloctests/tests/lib.rs

@@ -44,6 +44,7 @@
 #![feature(ptr_cast_slice)]
 #![allow(internal_features)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 #![deny(unsafe_op_in_unsafe_fn)]
 
 extern crate alloc;

library/alloctests/tests/sort/tests.rs

@@ -746,7 +746,7 @@ fn self_cmp<T: Ord + Clone + Debug, S: Sort>(
         pattern_fn(len).into_iter().map(|val| type_into_fn(val)).collect::<Vec<_>>();
 
     let comparison_fn = |a: &T, b: &T| {
-        assert_ne!(a as *const T as usize, b as *const T as usize);
+        assert_ne!(a as *const T, b as *const T);
         a.cmp(b)
     };
 

library/alloctests/tests/vec.rs

@@ -1110,7 +1110,7 @@ fn test_into_iter_zst() {
     struct AlignedZstWithDrop([u64; 0]);
     impl Drop for AlignedZstWithDrop {
         fn drop(&mut self) {
-            let addr = self as *mut _ as usize;
+            let addr = (self as *mut Self).addr();
             assert!(hint::black_box(addr) % align_of::<u64>() == 0);
         }
     }
@@ -1356,10 +1356,10 @@ fn overaligned_allocations() {
     for i in 0..0x1000 {
         v.reserve_exact(i);
         assert!(v[0].0 == 273);
-        assert!(v.as_ptr() as usize & 0xff == 0);
+        assert!(v.as_ptr().addr() & 0xff == 0);
         v.shrink_to_fit();
         assert!(v[0].0 == 273);
-        assert!(v.as_ptr() as usize & 0xff == 0);
+        assert!(v.as_ptr().addr() & 0xff == 0);
     }
 }
 
@@ -2574,7 +2574,7 @@ fn test_box_zero_allocator() {
 
         unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
             if layout.size() == 0 {
-                let addr = ptr.as_ptr() as usize;
+                let addr = ptr.as_ptr().addr();
                 let mut state = self.state.borrow_mut();
                 std::println!("freeing {addr}");
                 assert!(state.0.remove(&addr), "ZST free that wasn't allocated");

library/core/src/lib.rs

@@ -80,6 +80,7 @@
 #![deny(rust_2021_incompatible_or_patterns)]
 #![deny(unsafe_op_in_unsafe_fn)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 #![warn(deprecated_in_future)]
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]

library/core/src/ptr/const_ptr.rs

@@ -183,6 +183,7 @@ impl<T: PointeeSized> *const T {
     /// [`with_exposed_provenance`]: with_exposed_provenance
     #[inline(always)]
     #[stable(feature = "exposed_provenance", since = "1.84.0")]
+    #[expect(lossy_provenance_casts, reason = "this *is* the replacement")]
     pub fn expose_provenance(self) -> usize {
         self.cast::<()>() as usize
     }