Rollup merge of rust-lang#122935 - RalfJung:with-exposed-provenance, r=Amanieu

rename ptr::from_exposed_addr -> ptr::with_exposed_provenance

As discussed on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/136281-t-opsem/topic/To.20expose.20or.20not.20to.20expose/near/427757066).

The old name, `from_exposed_addr`, makes little sense as it's not the address that is exposed, it's the provenance. (`ptr.expose_addr()` stays unchanged as we haven't found a better option yet. The intended interpretation is "expose the provenance and return the address".)

The new name nicely matches `ptr::without_provenance`.

Author: jhpratt

core/src/intrinsics/simd.rs

@@ -549,6 +549,10 @@ extern "rust-intrinsic" {
     ///
     /// `U` must be a vector of pointers, with the same length as `T`.
     #[rustc_nounwind]
+    #[cfg(not(bootstrap))]
+    pub fn simd_with_exposed_provenance<T, U>(addr: T) -> U;
+    #[rustc_nounwind]
+    #[cfg(bootstrap)]
     pub fn simd_from_exposed_addr<T, U>(addr: T) -> U;
 
     /// Swap bytes of each element.
@@ -655,3 +659,6 @@ extern "rust-intrinsic" {
     #[rustc_nounwind]
     pub fn simd_flog<T>(a: T) -> T;
 }
+
+#[cfg(bootstrap)]
+pub use simd_from_exposed_addr as simd_with_exposed_provenance;

core/src/ptr/const_ptr.rs

@@ -165,7 +165,7 @@ impl<T: ?Sized> *const T {
     #[unstable(feature = "ptr_to_from_bits", issue = "91126")]
     #[deprecated(
         since = "1.67.0",
-        note = "replaced by the `ptr::from_exposed_addr` function, or update \
+        note = "replaced by the `ptr::with_exposed_provenance` function, or update \
             your code to follow the strict provenance rules using its APIs"
     )]
     #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
@@ -187,7 +187,7 @@ impl<T: ?Sized> *const T {
     ///
     /// If using those APIs is not possible because there is no way to preserve a pointer with the
     /// required provenance, then Strict Provenance might not be for you. Use pointer-integer casts
-    /// or [`expose_addr`][pointer::expose_addr] and [`from_exposed_addr`][from_exposed_addr]
+    /// or [`expose_addr`][pointer::expose_addr] and [`with_exposed_provenance`][with_exposed_provenance]
     /// instead. However, note that this makes your code less portable and less amenable to tools
     /// that check for compliance with the Rust memory model.
     ///
@@ -211,30 +211,30 @@ impl<T: ?Sized> *const T {
     }
 
     /// Gets the "address" portion of the pointer, and 'exposes' the "provenance" part for future
-    /// use in [`from_exposed_addr`][].
+    /// use in [`with_exposed_provenance`][].
     ///
     /// This is equivalent to `self as usize`, which semantically discards *provenance* and
     /// *address-space* information. Furthermore, this (like the `as` cast) has the implicit
     /// side-effect of marking the provenance as 'exposed', so on platforms that support it you can
-    /// later call [`from_exposed_addr`][] to reconstitute the original pointer including its
+    /// later call [`with_exposed_provenance`][] to reconstitute the original pointer including its
     /// provenance. (Reconstructing address space information, if required, is your responsibility.)
     ///
     /// Using this method means that code is *not* following [Strict
     /// Provenance][super#strict-provenance] rules. Supporting
-    /// [`from_exposed_addr`][] complicates specification and reasoning and may not be supported by
+    /// [`with_exposed_provenance`][] complicates specification and reasoning and may not be supported by
     /// tools that help you to stay conformant with the Rust memory model, so it is recommended to
     /// use [`addr`][pointer::addr] wherever possible.
     ///
     /// On most platforms this will produce a value with the same bytes as the original pointer,
     /// because all the bytes are dedicated to describing the address. Platforms which need to store
     /// additional information in the pointer may not support this operation, since the 'expose'
-    /// side-effect which is required for [`from_exposed_addr`][] to work is typically not
+    /// side-effect which is required for [`with_exposed_provenance`][] to work is typically not
     /// available.
     ///
     /// It is unclear whether this method can be given a satisfying unambiguous specification. This
     /// API and its claimed semantics are part of [Exposed Provenance][super#exposed-provenance].
     ///
-    /// [`from_exposed_addr`]: from_exposed_addr
+    /// [`with_exposed_provenance`]: with_exposed_provenance
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "exposed_provenance", issue = "95228")]

core/src/ptr/mod.rs

@@ -340,13 +340,13 @@
 //! clear where a satisfying unambiguous semantics can be defined for Exposed Provenance.
 //! Furthermore, Exposed Provenance will not work (well) with tools like [Miri] and [CHERI].
 //!
-//! Exposed Provenance is provided by the [`expose_addr`] and [`from_exposed_addr`] methods, which
+//! Exposed Provenance is provided by the [`expose_addr`] and [`with_exposed_provenance`] methods, which
 //! are meant to replace `as` casts between pointers and integers. [`expose_addr`] is a lot like
 //! [`addr`], but additionally adds the provenance of the pointer to a global list of 'exposed'
 //! provenances. (This list is purely conceptual, it exists for the purpose of specifying Rust but
-//! is not materialized in actual executions, except in tools like [Miri].) [`from_exposed_addr`]
+//! is not materialized in actual executions, except in tools like [Miri].) [`with_exposed_provenance`]
 //! can be used to construct a pointer with one of these previously 'exposed' provenances.
-//! [`from_exposed_addr`] takes only `addr: usize` as arguments, so unlike in [`with_addr`] there is
+//! [`with_exposed_provenance`] takes only `addr: usize` as arguments, so unlike in [`with_addr`] there is
 //! no indication of what the correct provenance for the returned pointer is -- and that is exactly
 //! what makes pointer-usize-pointer roundtrips so tricky to rigorously specify! There is no
 //! algorithm that decides which provenance will be used. You can think of this as "guessing" the
@@ -355,10 +355,10 @@
 //! there is *no* previously 'exposed' provenance that justifies the way the returned pointer will
 //! be used, the program has undefined behavior.
 //!
-//! Using [`expose_addr`] or [`from_exposed_addr`] (or the `as` casts) means that code is
+//! Using [`expose_addr`] or [`with_exposed_provenance`] (or the `as` casts) means that code is
 //! *not* following Strict Provenance rules. The goal of the Strict Provenance experiment is to
 //! determine how far one can get in Rust without the use of [`expose_addr`] and
-//! [`from_exposed_addr`], and to encourage code to be written with Strict Provenance APIs only.
+//! [`with_exposed_provenance`], and to encourage code to be written with Strict Provenance APIs only.
 //! Maximizing the amount of such code is a major win for avoiding specification complexity and to
 //! facilitate adoption of tools like [CHERI] and [Miri] that can be a big help in increasing the
 //! confidence in (unsafe) Rust code.
@@ -375,7 +375,7 @@
 //! [`addr`]: pointer::addr
 //! [`ptr::dangling`]: core::ptr::dangling
 //! [`expose_addr`]: pointer::expose_addr
-//! [`from_exposed_addr`]: from_exposed_addr
+//! [`with_exposed_provenance`]: with_exposed_provenance
 //! [Miri]: https://github.com/rust-lang/miri
 //! [CHERI]: https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/
 //! [Strict Provenance]: https://github.com/rust-lang/rust/issues/95228
@@ -581,7 +581,7 @@ pub const fn null_mut<T: ?Sized + Thin>() -> *mut T {
 /// little more than a usize address in disguise.
 ///
 /// This is different from `addr as *const T`, which creates a pointer that picks up a previously
-/// exposed provenance. See [`from_exposed_addr`] for more details on that operation.
+/// exposed provenance. See [`with_exposed_provenance`] for more details on that operation.
 ///
 /// This API and its claimed semantics are part of the Strict Provenance experiment,
 /// see the [module documentation][crate::ptr] for details.
@@ -592,7 +592,7 @@ pub const fn null_mut<T: ?Sized + Thin>() -> *mut T {
 pub const fn without_provenance<T>(addr: usize) -> *const T {
     // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
     // We use transmute rather than a cast so tools like Miri can tell that this
-    // is *not* the same as from_exposed_addr.
+    // is *not* the same as with_exposed_provenance.
     // SAFETY: every valid integer is also a valid pointer (as long as you don't dereference that
     // pointer).
     unsafe { mem::transmute(addr) }
@@ -625,7 +625,7 @@ pub const fn dangling<T>() -> *const T {
 /// little more than a usize address in disguise.
 ///
 /// This is different from `addr as *mut T`, which creates a pointer that picks up a previously
-/// exposed provenance. See [`from_exposed_addr_mut`] for more details on that operation.
+/// exposed provenance. See [`with_exposed_provenance_mut`] for more details on that operation.
 ///
 /// This API and its claimed semantics are part of the Strict Provenance experiment,
 /// see the [module documentation][crate::ptr] for details.
@@ -636,7 +636,7 @@ pub const fn dangling<T>() -> *const T {
 pub const fn without_provenance_mut<T>(addr: usize) -> *mut T {
     // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
     // We use transmute rather than a cast so tools like Miri can tell that this
-    // is *not* the same as from_exposed_addr.
+    // is *not* the same as with_exposed_provenance.
     // SAFETY: every valid integer is also a valid pointer (as long as you don't dereference that
     // pointer).
     unsafe { mem::transmute(addr) }
@@ -699,7 +699,7 @@ pub const fn dangling_mut<T>() -> *mut T {
 #[unstable(feature = "exposed_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[allow(fuzzy_provenance_casts)] // this *is* the explicit provenance API one should use instead
-pub fn from_exposed_addr<T>(addr: usize) -> *const T
+pub fn with_exposed_provenance<T>(addr: usize) -> *const T
 where
     T: Sized,
 {
@@ -739,7 +739,7 @@ where
 #[unstable(feature = "exposed_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[allow(fuzzy_provenance_casts)] // this *is* the explicit provenance API one should use instead
-pub fn from_exposed_addr_mut<T>(addr: usize) -> *mut T
+pub fn with_exposed_provenance_mut<T>(addr: usize) -> *mut T
 where
     T: Sized,
 {

core/src/ptr/mut_ptr.rs

@@ -171,7 +171,7 @@ impl<T: ?Sized> *mut T {
     #[unstable(feature = "ptr_to_from_bits", issue = "91126")]
     #[deprecated(
         since = "1.67.0",
-        note = "replaced by the `ptr::from_exposed_addr_mut` function, or \
+        note = "replaced by the `ptr::with_exposed_provenance_mut` function, or \
             update your code to follow the strict provenance rules using its APIs"
     )]
     #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
@@ -194,7 +194,7 @@ impl<T: ?Sized> *mut T {
     ///
     /// If using those APIs is not possible because there is no way to preserve a pointer with the
     /// required provenance, then Strict Provenance might not be for you. Use pointer-integer casts
-    /// or [`expose_addr`][pointer::expose_addr] and [`from_exposed_addr`][from_exposed_addr]
+    /// or [`expose_addr`][pointer::expose_addr] and [`with_exposed_provenance`][with_exposed_provenance]
     /// instead. However, note that this makes your code less portable and less amenable to tools
     /// that check for compliance with the Rust memory model.
     ///
@@ -218,30 +218,30 @@ impl<T: ?Sized> *mut T {
     }
 
     /// Gets the "address" portion of the pointer, and 'exposes' the "provenance" part for future
-    /// use in [`from_exposed_addr`][].
+    /// use in [`with_exposed_provenance`][].
     ///
     /// This is equivalent to `self as usize`, which semantically discards *provenance* and
     /// *address-space* information. Furthermore, this (like the `as` cast) has the implicit
     /// side-effect of marking the provenance as 'exposed', so on platforms that support it you can
-    /// later call [`from_exposed_addr_mut`][] to reconstitute the original pointer including its
+    /// later call [`with_exposed_provenance_mut`][] to reconstitute the original pointer including its
     /// provenance. (Reconstructing address space information, if required, is your responsibility.)
     ///
     /// Using this method means that code is *not* following [Strict
     /// Provenance][super#strict-provenance] rules. Supporting
-    /// [`from_exposed_addr_mut`][] complicates specification and reasoning and may not be supported
+    /// [`with_exposed_provenance_mut`][] complicates specification and reasoning and may not be supported
     /// by tools that help you to stay conformant with the Rust memory model, so it is recommended
     /// to use [`addr`][pointer::addr] wherever possible.
     ///
     /// On most platforms this will produce a value with the same bytes as the original pointer,
     /// because all the bytes are dedicated to describing the address. Platforms which need to store
     /// additional information in the pointer may not support this operation, since the 'expose'
-    /// side-effect which is required for [`from_exposed_addr_mut`][] to work is typically not
+    /// side-effect which is required for [`with_exposed_provenance_mut`][] to work is typically not
     /// available.
     ///
     /// It is unclear whether this method can be given a satisfying unambiguous specification. This
     /// API and its claimed semantics are part of [Exposed Provenance][super#exposed-provenance].
     ///
-    /// [`from_exposed_addr_mut`]: from_exposed_addr_mut
+    /// [`with_exposed_provenance_mut`]: with_exposed_provenance_mut
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "exposed_provenance", issue = "95228")]

portable-simd/crates/core_simd/src/simd/ptr/const_ptr.rs

@@ -51,13 +51,13 @@ pub trait SimdConstPtr: Copy + Sealed {
     fn with_addr(self, addr: Self::Usize) -> Self;
 
     /// Gets the "address" portion of the pointer, and "exposes" the provenance part for future use
-    /// in [`Self::from_exposed_addr`].
+    /// in [`Self::with_exposed_provenance`].
     fn expose_addr(self) -> Self::Usize;
 
     /// Convert an address back to a pointer, picking up a previously "exposed" provenance.
     ///
-    /// Equivalent to calling [`core::ptr::from_exposed_addr`] on each element.
-    fn from_exposed_addr(addr: Self::Usize) -> Self;
+    /// Equivalent to calling [`core::ptr::with_exposed_provenance`] on each element.
+    fn with_exposed_provenance(addr: Self::Usize) -> Self;
 
     /// Calculates the offset from a pointer using wrapping arithmetic.
     ///
@@ -137,9 +137,9 @@ where
     }
 
     #[inline]
-    fn from_exposed_addr(addr: Self::Usize) -> Self {
+    fn with_exposed_provenance(addr: Self::Usize) -> Self {
         // Safety: `self` is a pointer vector
-        unsafe { core::intrinsics::simd::simd_from_exposed_addr(addr) }
+        unsafe { core::intrinsics::simd::simd_with_exposed_provenance(addr) }
     }
 
     #[inline]

portable-simd/crates/core_simd/src/simd/ptr/mut_ptr.rs

@@ -48,13 +48,13 @@ pub trait SimdMutPtr: Copy + Sealed {
     fn with_addr(self, addr: Self::Usize) -> Self;
 
     /// Gets the "address" portion of the pointer, and "exposes" the provenance part for future use
-    /// in [`Self::from_exposed_addr`].
+    /// in [`Self::with_exposed_provenance`].
     fn expose_addr(self) -> Self::Usize;
 
     /// Convert an address back to a pointer, picking up a previously "exposed" provenance.
     ///
-    /// Equivalent to calling [`core::ptr::from_exposed_addr_mut`] on each element.
-    fn from_exposed_addr(addr: Self::Usize) -> Self;
+    /// Equivalent to calling [`core::ptr::with_exposed_provenance_mut`] on each element.
+    fn with_exposed_provenance(addr: Self::Usize) -> Self;
 
     /// Calculates the offset from a pointer using wrapping arithmetic.
     ///
@@ -134,9 +134,9 @@ where
     }
 
     #[inline]
-    fn from_exposed_addr(addr: Self::Usize) -> Self {
+    fn with_exposed_provenance(addr: Self::Usize) -> Self {
         // Safety: `self` is a pointer vector
-        unsafe { core::intrinsics::simd::simd_from_exposed_addr(addr) }
+        unsafe { core::intrinsics::simd::simd_with_exposed_provenance(addr) }
     }
 
     #[inline]

portable-simd/crates/core_simd/tests/pointers.rs

@@ -80,10 +80,10 @@ mod const_ptr {
             );
         }
 
-        fn from_exposed_addr<const LANES: usize>() {
+        fn with_exposed_provenance<const LANES: usize>() {
             test_helpers::test_unary_elementwise(
-                &Simd::<*const u32, LANES>::from_exposed_addr,
-                &core::ptr::from_exposed_addr::<u32>,
+                &Simd::<*const u32, LANES>::with_exposed_provenance,
+                &core::ptr::with_exposed_provenance::<u32>,
                 &|_| true,
             );
         }
@@ -103,10 +103,10 @@ mod mut_ptr {
             );
         }
 
-        fn from_exposed_addr<const LANES: usize>() {
+        fn with_exposed_provenance<const LANES: usize>() {
             test_helpers::test_unary_elementwise(
-                &Simd::<*mut u32, LANES>::from_exposed_addr,
-                &core::ptr::from_exposed_addr_mut::<u32>,
+                &Simd::<*mut u32, LANES>::with_exposed_provenance,
+                &core::ptr::with_exposed_provenance_mut::<u32>,
                 &|_| true,
             );
         }

std/src/os/xous/ffi.rs

@@ -389,7 +389,7 @@ pub(crate) unsafe fn map_memory<T>(
     let result = a0;
 
     if result == SyscallResult::MemoryRange as usize {
-        let start = core::ptr::from_exposed_addr_mut::<T>(a1);
+        let start = core::ptr::with_exposed_provenance_mut::<T>(a1);
         let len = a2 / core::mem::size_of::<T>();
         let end = unsafe { start.add(len) };
         Ok(unsafe { core::slice::from_raw_parts_mut(start, len) })

std/src/sys/pal/hermit/thread.rs

@@ -47,7 +47,7 @@ impl Thread {
         extern "C" fn thread_start(main: usize) {
             unsafe {
                 // Finally, let's run some code.
-                Box::from_raw(ptr::from_exposed_addr::<Box<dyn FnOnce()>>(main).cast_mut())();
+                Box::from_raw(ptr::with_exposed_provenance::<Box<dyn FnOnce()>>(main).cast_mut())();
 
                 // run all destructors
                 run_dtors();

std/src/sys/pal/itron/thread.rs

@@ -98,7 +98,7 @@ impl Thread {
         });
 
         unsafe extern "C" fn trampoline(exinf: isize) {
-            let p_inner: *mut ThreadInner = crate::ptr::from_exposed_addr_mut(exinf as usize);
+            let p_inner: *mut ThreadInner = crate::ptr::with_exposed_provenance_mut(exinf as usize);
             // Safety: `ThreadInner` is alive at this point
             let inner = unsafe { &*p_inner };