Auto merge of #97791 - m-ou-se:const-locks, r=m-ou-se

Make {Mutex, Condvar, RwLock}::new() const.

This makes it possible to have `static M: Mutex<_> = Mutex::new(..);` 🎉

Our implementations [on Linux](https://github.com/rust-lang/rust/pull/95035), [on Windows](https://github.com/rust-lang/rust/pull/77380), and various BSDs and some tier 3 platforms have already been using a non-allocating const-constructible implementation. As of https://github.com/rust-lang/rust/pull/97647, the remaining platforms (most notably macOS) now have a const-constructible implementation as well. This means we can finally make these functions publicly const.

Tracking issue: https://github.com/rust-lang/rust/issues/93740

8 files changed, 8 insertions, 0 deletions

diff --git a/library/std/src/sys/itron/mutex.rs b/library/std/src/sys/itron/mutex.rs
index 2ba8454ff92..715e94c3b3d 100644
--- a/library/std/src/sys/itron/mutex.rs
+++ b/library/std/src/sys/itron/mutex.rs
@@ -26,6 +26,7 @@ fn new_mtx() -> Result<abi::ID, ItronError> {
 }
 
 impl Mutex {
+    #[inline]
     pub const fn new() -> Mutex {
         Mutex { mtx: SpinIdOnceCell::new() }
     }
diff --git a/library/std/src/sys/solid/rwlock.rs b/library/std/src/sys/solid/rwlock.rs
index 433abc895f5..0a770cf03f2 100644
--- a/library/std/src/sys/solid/rwlock.rs
+++ b/library/std/src/sys/solid/rwlock.rs
@@ -23,6 +23,7 @@ fn new_rwl() -> Result<abi::ID, ItronError> {
 }
 
 impl RwLock {
+    #[inline]
     pub const fn new() -> RwLock {
         RwLock { rwl: SpinIdOnceCell::new() }
     }
diff --git a/library/std/src/sys/unsupported/locks/condvar.rs b/library/std/src/sys/unsupported/locks/condvar.rs
index f27bf2b26bd..e703fd0d269 100644
--- a/library/std/src/sys/unsupported/locks/condvar.rs
+++ b/library/std/src/sys/unsupported/locks/condvar.rs
@@ -6,6 +6,7 @@ pub struct Condvar {}
 pub type MovableCondvar = Condvar;
 
 impl Condvar {
+    #[inline]
     pub const fn new() -> Condvar {
         Condvar {}
     }
diff --git a/library/std/src/sys/unsupported/locks/mutex.rs b/library/std/src/sys/unsupported/locks/mutex.rs
index 56bad71b189..d7cb12e0cf9 100644
--- a/library/std/src/sys/unsupported/locks/mutex.rs
+++ b/library/std/src/sys/unsupported/locks/mutex.rs
@@ -11,6 +11,7 @@ unsafe impl Send for Mutex {}
 unsafe impl Sync for Mutex {} // no threads on this platform
 
 impl Mutex {
+    #[inline]
     pub const fn new() -> Mutex {
         Mutex { locked: Cell::new(false) }
     }
diff --git a/library/std/src/sys/unsupported/locks/rwlock.rs b/library/std/src/sys/unsupported/locks/rwlock.rs
index bf6e2d3d080..aca5fb7152c 100644
--- a/library/std/src/sys/unsupported/locks/rwlock.rs
+++ b/library/std/src/sys/unsupported/locks/rwlock.rs
@@ -11,6 +11,7 @@ unsafe impl Send for RwLock {}
 unsafe impl Sync for RwLock {} // no threads on this platform
 
 impl RwLock {
+    #[inline]
     pub const fn new() -> RwLock {
         RwLock { mode: Cell::new(0) }
     }
diff --git a/library/std/src/sys/windows/locks/condvar.rs b/library/std/src/sys/windows/locks/condvar.rs
index 59e2c1be0f0..be9a2abbe35 100644
--- a/library/std/src/sys/windows/locks/condvar.rs
+++ b/library/std/src/sys/windows/locks/condvar.rs
@@ -14,6 +14,7 @@ unsafe impl Send for Condvar {}
 unsafe impl Sync for Condvar {}
 
 impl Condvar {
+    #[inline]
     pub const fn new() -> Condvar {
         Condvar { inner: UnsafeCell::new(c::CONDITION_VARIABLE_INIT) }
     }
diff --git a/library/std/src/sys/windows/locks/mutex.rs b/library/std/src/sys/windows/locks/mutex.rs
index 08f55844a0e..f91e8f9f59a 100644
--- a/library/std/src/sys/windows/locks/mutex.rs
+++ b/library/std/src/sys/windows/locks/mutex.rs
@@ -33,6 +33,7 @@ pub unsafe fn raw(m: &Mutex) -> c::PSRWLOCK {
 }
 
 impl Mutex {
+    #[inline]
     pub const fn new() -> Mutex {
         Mutex { srwlock: UnsafeCell::new(c::SRWLOCK_INIT) }
     }
diff --git a/library/std/src/sys/windows/locks/rwlock.rs b/library/std/src/sys/windows/locks/rwlock.rs
index a32df85e2f6..fa5ffe5749f 100644
--- a/library/std/src/sys/windows/locks/rwlock.rs
+++ b/library/std/src/sys/windows/locks/rwlock.rs
@@ -11,6 +11,7 @@ unsafe impl Send for RwLock {}
 unsafe impl Sync for RwLock {}
 
 impl RwLock {
+    #[inline]
     pub const fn new() -> RwLock {
         RwLock { inner: UnsafeCell::new(c::SRWLOCK_INIT) }
     }