Auto merge of #85711 - JohnTitor:rollup-8why04t, r=JohnTitor

Rollup of 12 pull requests

Successful merges:

 - #84048 (Avoid CJK legacy fonts in Windows)
 - #85529 (doc: clarify Mutex::try_lock, etc. errors)
 - #85590 (Fix bootstrap using host exe suffix for cargo)
 - #85610 (Fix pointer provenance in <[T]>::copy_within)
 - #85623 (Remove stray .stderr files)
 - #85645 (Demote `ControlFlow::{from|into}_try` to `pub(crate)`)
 - #85647 (Revert "Move llvm submodule updates to rustbuild")
 - #85666 (Document shared_from_cow functions)
 - #85668 (Fix tasklist example in rustdoc book.)
 - #85672 (Move stability attribute for items under the `ip` feature)
 - #85699 (Update books)
 - #85701 (Update cargo)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

library/alloc/src/rc.rs

@@ -1859,6 +1859,18 @@ where
     B: ToOwned + ?Sized,
     Rc<B>: From<&'a B> + From<B::Owned>,
 {
+    /// Create a reference-counted pointer from
+    /// a clone-on-write pointer by copying its content.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use std::rc::Rc;
+    /// # use std::borrow::Cow;
+    /// let cow: Cow<str> = Cow::Borrowed("eggplant");
+    /// let shared: Rc<str> = Rc::from(cow);
+    /// assert_eq!("eggplant", &shared[..]);
+    /// ```
     #[inline]
     fn from(cow: Cow<'a, B>) -> Rc<B> {
         match cow {

library/alloc/src/sync.rs

@@ -2413,6 +2413,18 @@ where
     B: ToOwned + ?Sized,
     Arc<B>: From<&'a B> + From<B::Owned>,
 {
+    /// Create an atomically reference-counted pointer from
+    /// a clone-on-write pointer by copying its content.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use std::sync::Arc;
+    /// # use std::borrow::Cow;
+    /// let cow: Cow<str> = Cow::Borrowed("eggplant");
+    /// let shared: Arc<str> = Arc::from(cow);
+    /// assert_eq!("eggplant", &shared[..]);
+    /// ```
     #[inline]
     fn from(cow: Cow<'a, B>) -> Arc<B> {
         match cow {

library/core/src/ops/control_flow.rs

@@ -187,42 +187,41 @@ impl<B, C> ControlFlow<B, C> {
 #[cfg(bootstrap)]
 impl<R: ops::TryV1> ControlFlow<R, R::Output> {
     /// Create a `ControlFlow` from any type implementing `Try`.
-    #[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
     #[inline]
-    pub fn from_try(r: R) -> Self {
+    pub(crate) fn from_try(r: R) -> Self {
         match R::into_result(r) {
             Ok(v) => ControlFlow::Continue(v),
             Err(v) => ControlFlow::Break(R::from_error(v)),
         }
     }
 
     /// Convert a `ControlFlow` into any type implementing `Try`;
-    #[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
     #[inline]
-    pub fn into_try(self) -> R {
+    pub(crate) fn into_try(self) -> R {
         match self {
             ControlFlow::Continue(v) => R::from_ok(v),
             ControlFlow::Break(v) => v,
         }
     }
 }
 
+/// These are used only as part of implementing the iterator adapters.
+/// They have mediocre names and non-obvious semantics, so aren't
+/// currently on a path to potential stabilization.
 #[cfg(not(bootstrap))]
 impl<R: ops::TryV2> ControlFlow<R, R::Output> {
     /// Create a `ControlFlow` from any type implementing `Try`.
-    #[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
     #[inline]
-    pub fn from_try(r: R) -> Self {
+    pub(crate) fn from_try(r: R) -> Self {
         match R::branch(r) {
             ControlFlow::Continue(v) => ControlFlow::Continue(v),
             ControlFlow::Break(v) => ControlFlow::Break(R::from_residual(v)),
         }
     }
 
     /// Convert a `ControlFlow` into any type implementing `Try`;
-    #[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
     #[inline]
-    pub fn into_try(self) -> R {
+    pub(crate) fn into_try(self) -> R {
         match self {
             ControlFlow::Continue(v) => R::from_output(v),
             ControlFlow::Break(v) => v,

library/core/src/slice/mod.rs

@@ -3096,7 +3096,11 @@ impl<T> [T] {
         // SAFETY: the conditions for `ptr::copy` have all been checked above,
         // as have those for `ptr::add`.
         unsafe {
-            ptr::copy(self.as_ptr().add(src_start), self.as_mut_ptr().add(dest), count);
+            // Derive both `src_ptr` and `dest_ptr` from the same loan
+            let ptr = self.as_mut_ptr();
+            let src_ptr = ptr.add(src_start);
+            let dest_ptr = ptr.add(dest);
+            ptr::copy(src_ptr, dest_ptr, count);
         }
     }
 

library/std/src/net/ip.rs

@@ -1,11 +1,3 @@
-#![unstable(
-    feature = "ip",
-    reason = "extra functionality has not been \
-                                      scrutinized to the level that it should \
-                                      be to be stable",
-    issue = "27709"
-)]
-
 // Tests for this module
 #[cfg(all(test, not(target_os = "emscripten")))]
 mod tests;
@@ -126,6 +118,7 @@ pub struct Ipv6Addr {
 
 #[allow(missing_docs)]
 #[derive(Copy, PartialEq, Eq, Clone, Hash, Debug)]
+#[unstable(feature = "ip", issue = "27709")]
 pub enum Ipv6MulticastScope {
     InterfaceLocal,
     LinkLocal,
@@ -199,6 +192,7 @@ impl IpAddr {
     /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0x1c9, 0, 0, 0xafc8, 0, 0x1)).is_global(), true);
     /// ```
     #[rustc_const_unstable(feature = "const_ip", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_global(&self) -> bool {
         match self {
@@ -249,6 +243,7 @@ impl IpAddr {
     /// );
     /// ```
     #[rustc_const_unstable(feature = "const_ip", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_documentation(&self) -> bool {
         match self {
@@ -549,6 +544,7 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(80, 9, 12, 3).is_global(), true);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_global(&self) -> bool {
         // check if this address is 192.0.0.9 or 192.0.0.10. These addresses are the only two
@@ -587,6 +583,7 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(100, 128, 0, 0).is_shared(), false);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_shared(&self) -> bool {
         self.octets()[0] == 100 && (self.octets()[1] & 0b1100_0000 == 0b0100_0000)
@@ -620,6 +617,7 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(191, 255, 255, 255).is_ietf_protocol_assignment(), false);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_ietf_protocol_assignment(&self) -> bool {
         self.octets()[0] == 192 && self.octets()[1] == 0 && self.octets()[2] == 0
@@ -644,6 +642,7 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(198, 20, 0, 0).is_benchmarking(), false);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_benchmarking(&self) -> bool {
         self.octets()[0] == 198 && (self.octets()[1] & 0xfe) == 18
@@ -677,6 +676,7 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_reserved(), false);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_reserved(&self) -> bool {
         self.octets()[0] & 240 == 240 && !self.is_broadcast()
@@ -1234,6 +1234,7 @@ impl Ipv6Addr {
     /// assert_eq!(Ipv6Addr::new(0, 0, 0x1c9, 0, 0, 0xafc8, 0, 0x1).is_global(), true);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_global(&self) -> bool {
         match self.multicast_scope() {
@@ -1260,6 +1261,7 @@ impl Ipv6Addr {
     /// assert_eq!(Ipv6Addr::new(0xfc02, 0, 0, 0, 0, 0, 0, 0).is_unique_local(), true);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_unique_local(&self) -> bool {
         (self.segments()[0] & 0xfe00) == 0xfc00
@@ -1315,6 +1317,7 @@ impl Ipv6Addr {
     /// [IETF RFC 4291 section 2.5.6]: https://tools.ietf.org/html/rfc4291#section-2.5.6
     /// [RFC 4291 errata 4406]: https://www.rfc-editor.org/errata/eid4406
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_unicast_link_local_strict(&self) -> bool {
         matches!(self.segments(), [0xfe80, 0, 0, 0, ..])
@@ -1369,6 +1372,7 @@ impl Ipv6Addr {
     /// [IETF RFC 4291 section 2.4]: https://tools.ietf.org/html/rfc4291#section-2.4
     /// [RFC 4291 errata 4406]: https://www.rfc-editor.org/errata/eid4406
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_unicast_link_local(&self) -> bool {
         (self.segments()[0] & 0xffc0) == 0xfe80
@@ -1409,6 +1413,7 @@ impl Ipv6Addr {
     ///
     /// [RFC 3879]: https://tools.ietf.org/html/rfc3879
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_unicast_site_local(&self) -> bool {
         (self.segments()[0] & 0xffc0) == 0xfec0
@@ -1432,6 +1437,7 @@ impl Ipv6Addr {
     /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_documentation(), true);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_documentation(&self) -> bool {
         (self.segments()[0] == 0x2001) && (self.segments()[1] == 0xdb8)
@@ -1468,6 +1474,7 @@ impl Ipv6Addr {
     /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_unicast_global(), true);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn is_unicast_global(&self) -> bool {
         !self.is_multicast()
@@ -1494,6 +1501,7 @@ impl Ipv6Addr {
     /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).multicast_scope(), None);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn multicast_scope(&self) -> Option<Ipv6MulticastScope> {
         if self.is_multicast() {
@@ -1555,6 +1563,7 @@ impl Ipv6Addr {
     /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1).to_ipv4_mapped(), None);
     /// ```
     #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+    #[unstable(feature = "ip", issue = "27709")]
     #[inline]
     pub const fn to_ipv4_mapped(&self) -> Option<Ipv4Addr> {
         match self.octets() {

library/std/src/sync/mutex.rs

@@ -294,8 +294,14 @@ impl<T: ?Sized> Mutex<T> {
     /// # Errors
     ///
     /// If another user of this mutex panicked while holding the mutex, then
-    /// this call will return an error if the mutex would otherwise be
-    /// acquired.
+    /// this call will return the [`Poisoned`] error if the mutex would
+    /// otherwise be acquired.
+    ///
+    /// If the mutex could not be acquired because it is already locked, then
+    /// this call will return the [`WouldBlock`] error.
+    ///
+    /// [`Poisoned`]: TryLockError::Poisoned
+    /// [`WouldBlock`]: TryLockError::WouldBlock
     ///
     /// # Examples
     ///

library/std/src/sync/rwlock.rs

@@ -199,11 +199,17 @@ impl<T: ?Sized> RwLock<T> {
     ///
     /// # Errors
     ///
-    /// This function will return an error if the RwLock is poisoned. An RwLock
-    /// is poisoned whenever a writer panics while holding an exclusive lock. An
-    /// error will only be returned if the lock would have otherwise been
+    /// This function will return the [`Poisoned`] error if the RwLock is poisoned.
+    /// An RwLock is poisoned whenever a writer panics while holding an exclusive
+    /// lock. `Poisoned` will only be returned if the lock would have otherwise been
     /// acquired.
     ///
+    /// This function will return the [`WouldBlock`] error if the RwLock could not
+    /// be acquired because it was already locked exclusively.
+    ///
+    /// [`Poisoned`]: TryLockError::Poisoned
+    /// [`WouldBlock`]: TryLockError::WouldBlock
+    ///
     /// # Examples
     ///
     /// ```
@@ -281,10 +287,17 @@ impl<T: ?Sized> RwLock<T> {
     ///
     /// # Errors
     ///
-    /// This function will return an error if the RwLock is poisoned. An RwLock
-    /// is poisoned whenever a writer panics while holding an exclusive lock. An
-    /// error will only be returned if the lock would have otherwise been
-    /// acquired.
+    /// This function will return the [`Poisoned`] error if the RwLock is
+    /// poisoned. An RwLock is poisoned whenever a writer panics while holding
+    /// an exclusive lock. `Poisoned` will only be returned if the lock would have
+    /// otherwise been acquired.
+    ///
+    /// This function will return the [`WouldBlock`] error if the RwLock could not
+    /// be acquired because it was already locked exclusively.
+    ///
+    /// [`Poisoned`]: TryLockError::Poisoned
+    /// [`WouldBlock`]: TryLockError::WouldBlock
+    ///
     ///
     /// # Examples
     ///

src/bootstrap/bootstrap.py

@@ -991,20 +991,28 @@ def update_submodules(self):
         ).decode(default_encoding).splitlines()]
         filtered_submodules = []
         submodules_names = []
+        llvm_checked_out = os.path.exists(os.path.join(self.rust_root, "src/llvm-project/.git"))
+        external_llvm_provided = self.get_toml('llvm-config') or self.downloading_llvm()
+        llvm_needed = not self.get_toml('codegen-backends', 'rust') \
+            or "llvm" in self.get_toml('codegen-backends', 'rust')
         for module in submodules:
-            # This is handled by native::Llvm in rustbuild, not here
             if module.endswith("llvm-project"):
-                continue
+                # Don't sync the llvm-project submodule if an external LLVM was
+                # provided, if we are downloading LLVM or if the LLVM backend is
+                # not being built. Also, if the submodule has been initialized
+                # already, sync it anyways so that it doesn't mess up contributor
+                # pull requests.
+                if external_llvm_provided or not llvm_needed:
+                    if self.get_toml('lld') != 'true' and not llvm_checked_out:
+                        continue
             check = self.check_submodule(module, slow_submodules)
             filtered_submodules.append((module, check))
             submodules_names.append(module)
         recorded = subprocess.Popen(["git", "ls-tree", "HEAD"] + submodules_names,
                                     cwd=self.rust_root, stdout=subprocess.PIPE)
         recorded = recorded.communicate()[0].decode(default_encoding).strip().splitlines()
-        # { filename: hash }
         recorded_submodules = {}
         for data in recorded:
-            # [mode, kind, hash, filename]
             data = data.split()
             recorded_submodules[data[3]] = data[2]
         for module in filtered_submodules:

src/bootstrap/lib.rs

@@ -472,22 +472,12 @@ impl Build {
         slice::from_ref(&self.build.triple)
     }
 
-    /// If the LLVM submodule has been initialized already, sync it unconditionally. This avoids
-    /// contributors checking in a submodule change by accident.
-    pub fn maybe_update_llvm_submodule(&self) {
-        if self.in_tree_llvm_info.is_git() {
-            native::update_llvm_submodule(self);
-        }
-    }
-
     /// Executes the entire build, as configured by the flags and configuration.
     pub fn build(&mut self) {
         unsafe {
             job::setup(self);
         }
 
-        self.maybe_update_llvm_submodule();
-
         if let Subcommand::Format { check, paths } = &self.config.cmd {
             return format::format(self, *check, &paths);
         }