Auto merge of #86186 - JohnTitor:rollup-upaw6wx, r=JohnTitor

Rollup of 7 pull requests

Successful merges:

 - #82037 (Make symbols stripping work on MacOS X)
 - #84687 (Multiple improvements to RwLocks)
 - #85997 (rustdoc: Print a warning if the diff when comparing to old nightlies is empty)
 - #86051 (Updated code examples and wording in move keyword documentation )
 - #86111 (fix off by one in `std::iter::Iterator` documentation)
 - #86113 (build doctests with lld if use-lld = true)
 - #86175 (update Miri)

Failed merges:

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

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -5,7 +5,7 @@ use rustc_fs_util::fix_windows_verbatim_for_gcc;
 use rustc_hir::def_id::CrateNum;
 use rustc_middle::middle::cstore::{DllImport, LibSource};
 use rustc_middle::middle::dependency_format::Linkage;
-use rustc_session::config::{self, CFGuard, CrateType, DebugInfo};
+use rustc_session::config::{self, CFGuard, CrateType, DebugInfo, Strip};
 use rustc_session::config::{OutputFilenames, OutputType, PrintRequest};
 use rustc_session::output::{check_file_is_writeable, invalid_output_for_target, out_filename};
 use rustc_session::search_paths::PathKind;
@@ -907,14 +907,6 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(
         }
     }
 
-    fn escape_string(s: &[u8]) -> String {
-        str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
-            let mut x = "Non-UTF-8 output: ".to_string();
-            x.extend(s.iter().flat_map(|&b| ascii::escape_default(b)).map(char::from));
-            x
-        })
-    }
-
     match prog {
         Ok(prog) => {
             if !prog.status.success() {
@@ -1056,6 +1048,47 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(
         // ... and otherwise we're processing a `*.dwp` packed dwarf file.
         SplitDebuginfo::Packed => link_dwarf_object(sess, &out_filename),
     }
+
+    if sess.target.is_like_osx {
+        if let Some(option) = osx_strip_opt(sess.opts.debugging_opts.strip) {
+            strip_symbols_in_osx(sess, &out_filename, option);
+        }
+    }
+}
+
+fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: &str) {
+    let prog = Command::new("strip").arg(option).arg(out_filename).output();
+    match prog {
+        Ok(prog) => {
+            if !prog.status.success() {
+                let mut output = prog.stderr.clone();
+                output.extend_from_slice(&prog.stdout);
+                sess.struct_warn(&format!(
+                    "stripping debug info with `strip` failed: {}",
+                    prog.status
+                ))
+                .note(&escape_string(&output))
+                .emit();
+            }
+        }
+        Err(e) => sess.fatal(&format!("unable to run `strip`: {}", e)),
+    }
+}
+
+fn osx_strip_opt<'a>(strip: Strip) -> Option<&'a str> {
+    match strip {
+        Strip::Debuginfo => Some("-S"),
+        Strip::Symbols => Some("-x"),
+        Strip::None => None,
+    }
+}
+
+fn escape_string(s: &[u8]) -> String {
+    str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
+        let mut x = "Non-UTF-8 output: ".to_string();
+        x.extend(s.iter().flat_map(|&b| ascii::escape_default(b)).map(char::from));
+        x
+    })
 }
 
 fn add_sanitizer_libraries(sess: &Session, crate_type: CrateType, linker: &mut dyn Linker) {

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -526,15 +526,18 @@ impl<'a> Linker for GccLinker<'a> {
     fn control_flow_guard(&mut self) {}
 
     fn debuginfo(&mut self, strip: Strip) {
+        // MacOS linker doesn't support stripping symbols directly anymore.
+        if self.sess.target.is_like_osx {
+            return;
+        }
+
         match strip {
             Strip::None => {}
             Strip::Debuginfo => {
-                // MacOS linker does not support longhand argument --strip-debug
-                self.linker_arg("-S");
+                self.linker_arg("--strip-debug");
             }
             Strip::Symbols => {
-                // MacOS linker does not support longhand argument --strip-all
-                self.linker_arg("-s");
+                self.linker_arg("--strip-all");
             }
         }
     }

library/core/src/iter/traits/iterator.rs

@@ -138,7 +138,7 @@ pub trait Iterator {
     /// A more complex example:
     ///
     /// ```
-    /// // The even numbers from zero to ten.
+    /// // The even numbers in the range of zero to nine.
     /// let iter = (0..10).filter(|x| x % 2 == 0);
     ///
     /// // We might iterate from zero to ten times. Knowing that it's five

library/std/src/keyword_docs.rs

@@ -987,13 +987,13 @@ mod mod_keyword {}
 /// Capture a [closure]'s environment by value.
 ///
 /// `move` converts any variables captured by reference or mutable reference
-/// to owned by value variables.
+/// to variables captured by value.
 ///
 /// ```rust
-/// let capture = "hello";
-/// let closure = move || {
-///     println!("rust says {}", capture);
-/// };
+/// let data = vec![1, 2, 3];
+/// let closure = move || println!("captured {:?} by value", data);
+///
+/// // data is no longer available, it is owned by the closure
 /// ```
 ///
 /// Note: `move` closures may still implement [`Fn`] or [`FnMut`], even though
@@ -1004,31 +1004,29 @@ mod mod_keyword {}
 /// ```rust
 /// fn create_fn() -> impl Fn() {
 ///     let text = "Fn".to_owned();
-///
 ///     move || println!("This is a: {}", text)
 /// }
 ///
 /// let fn_plain = create_fn();
-///
 /// fn_plain();
 /// ```
 ///
 /// `move` is often used when [threads] are involved.
 ///
 /// ```rust
-/// let x = 5;
+/// let data = vec![1, 2, 3];
 ///
 /// std::thread::spawn(move || {
-///     println!("captured {} by value", x)
+///     println!("captured {:?} by value", data)
 /// }).join().unwrap();
 ///
-/// // x is no longer available
+/// // data was moved to the spawned thread, so we cannot use it here
 /// ```
 ///
 /// `move` is also valid before an async block.
 ///
 /// ```rust
-/// let capture = "hello";
+/// let capture = "hello".to_owned();
 /// let block = async move {
 ///     println!("rust says {} from async block", capture);
 /// };

library/std/src/panicking.rs

@@ -19,7 +19,7 @@ use crate::process;
 use crate::sync::atomic::{AtomicBool, Ordering};
 use crate::sys::stdio::panic_output;
 use crate::sys_common::backtrace::{self, RustBacktrace};
-use crate::sys_common::rwlock::RWLock;
+use crate::sys_common::rwlock::StaticRWLock;
 use crate::sys_common::thread_info;
 use crate::thread;
 
@@ -74,7 +74,7 @@ enum Hook {
     Custom(*mut (dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send)),
 }
 
-static HOOK_LOCK: RWLock = RWLock::new();
+static HOOK_LOCK: StaticRWLock = StaticRWLock::new();
 static mut HOOK: Hook = Hook::Default;
 
 /// Registers a custom panic hook, replacing any that was previously registered.
@@ -117,10 +117,10 @@ pub fn set_hook(hook: Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send>) {
     }
 
     unsafe {
-        HOOK_LOCK.write();
+        let guard = HOOK_LOCK.write();
         let old_hook = HOOK;
         HOOK = Hook::Custom(Box::into_raw(hook));
-        HOOK_LOCK.write_unlock();
+        drop(guard);
 
         if let Hook::Custom(ptr) = old_hook {
             #[allow(unused_must_use)]
@@ -165,10 +165,10 @@ pub fn take_hook() -> Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send> {
     }
 
     unsafe {
-        HOOK_LOCK.write();
+        let guard = HOOK_LOCK.write();
         let hook = HOOK;
         HOOK = Hook::Default;
-        HOOK_LOCK.write_unlock();
+        drop(guard);
 
         match hook {
             Hook::Default => Box::new(default_hook),
@@ -608,7 +608,7 @@ fn rust_panic_with_hook(
 
     unsafe {
         let mut info = PanicInfo::internal_constructor(message, location);
-        HOOK_LOCK.read();
+        let _guard = HOOK_LOCK.read();
         match HOOK {
             // Some platforms (like wasm) know that printing to stderr won't ever actually
             // print anything, and if that's the case we can skip the default
@@ -626,7 +626,6 @@ fn rust_panic_with_hook(
                 (*ptr)(&info);
             }
         };
-        HOOK_LOCK.read_unlock();
     }
 
     if panics > 1 {

library/std/src/sync/rwlock.rs

@@ -3,9 +3,7 @@ mod tests;
 
 use crate::cell::UnsafeCell;
 use crate::fmt;
-use crate::mem;
 use crate::ops::{Deref, DerefMut};
-use crate::ptr;
 use crate::sync::{poison, LockResult, TryLockError, TryLockResult};
 use crate::sys_common::rwlock as sys;
 
@@ -66,7 +64,7 @@ use crate::sys_common::rwlock as sys;
 /// [`Mutex`]: super::Mutex
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct RwLock<T: ?Sized> {
-    inner: Box<sys::RWLock>,
+    inner: sys::MovableRWLock,
     poison: poison::Flag,
     data: UnsafeCell<T>,
 }
@@ -130,7 +128,7 @@ impl<T> RwLock<T> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new(t: T) -> RwLock<T> {
         RwLock {
-            inner: box sys::RWLock::new(),
+            inner: sys::MovableRWLock::new(),
             poison: poison::Flag::new(),
             data: UnsafeCell::new(t),
         }
@@ -376,24 +374,8 @@ impl<T: ?Sized> RwLock<T> {
     where
         T: Sized,
     {
-        // We know statically that there are no outstanding references to
-        // `self` so there's no need to lock the inner lock.
-        //
-        // To get the inner value, we'd like to call `data.into_inner()`,
-        // but because `RwLock` impl-s `Drop`, we can't move out of it, so
-        // we'll have to destructure it manually instead.
-        unsafe {
-            // Like `let RwLock { inner, poison, data } = self`.
-            let (inner, poison, data) = {
-                let RwLock { ref inner, ref poison, ref data } = self;
-                (ptr::read(inner), ptr::read(poison), ptr::read(data))
-            };
-            mem::forget(self);
-            inner.destroy(); // Keep in sync with the `Drop` impl.
-            drop(inner);
-
-            poison::map_result(poison.borrow(), |_| data.into_inner())
-        }
+        let data = self.data.into_inner();
+        poison::map_result(self.poison.borrow(), |_| data)
     }
 
     /// Returns a mutable reference to the underlying data.
@@ -424,14 +406,6 @@ impl<T: ?Sized> RwLock<T> {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<#[may_dangle] T: ?Sized> Drop for RwLock<T> {
-    fn drop(&mut self) {
-        // IMPORTANT: This code needs to be kept in sync with `RwLock::into_inner`.
-        unsafe { self.inner.destroy() }
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + fmt::Debug> fmt::Debug for RwLock<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

library/std/src/sys/hermit/rwlock.rs

@@ -8,6 +8,8 @@ pub struct RWLock {
     state: UnsafeCell<State>,
 }
 
+pub type MovableRWLock = Box<RWLock>;
+
 enum State {
     Unlocked,
     Reading(usize),

library/std/src/sys/sgx/rwlock.rs

@@ -13,6 +13,8 @@ pub struct RWLock {
     writer: SpinMutex<WaitVariable<bool>>,
 }
 
+pub type MovableRWLock = Box<RWLock>;
+
 // Check at compile time that RWLock size matches C definition (see test_c_rwlock_initializer below)
 //
 // # Safety

library/std/src/sys/unix/os.rs

@@ -20,8 +20,7 @@ use crate::str;
 use crate::sys::cvt;
 use crate::sys::fd;
 use crate::sys::memchr;
-use crate::sys::rwlock::{RWLockReadGuard, StaticRWLock};
-use crate::sys_common::mutex::{StaticMutex, StaticMutexGuard};
+use crate::sys_common::rwlock::{StaticRWLock, StaticRWLockReadGuard};
 use crate::vec;
 
 use libc::{c_char, c_int, c_void};
@@ -490,8 +489,8 @@ pub unsafe fn environ() -> *mut *const *const c_char {
 
 static ENV_LOCK: StaticRWLock = StaticRWLock::new();
 
-pub fn env_read_lock() -> RWLockReadGuard {
-    ENV_LOCK.read_with_guard()
+pub fn env_read_lock() -> StaticRWLockReadGuard {
+    ENV_LOCK.read()
 }
 
 /// Returns a vector of (variable, value) byte-vector pairs for all the
@@ -551,7 +550,7 @@ pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     let v = CString::new(v.as_bytes())?;
 
     unsafe {
-        let _guard = ENV_LOCK.write_with_guard();
+        let _guard = ENV_LOCK.write();
         cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(drop)
     }
 }
@@ -560,7 +559,7 @@ pub fn unsetenv(n: &OsStr) -> io::Result<()> {
     let nbuf = CString::new(n.as_bytes())?;
 
     unsafe {
-        let _guard = ENV_LOCK.write_with_guard();
+        let _guard = ENV_LOCK.write();
         cvt(libc::unsetenv(nbuf.as_ptr())).map(drop)
     }
 }