Add initial parking_lot module with raw_rwlock

Author: faern

src/libstd/sys_common/mod.rs

@@ -45,6 +45,7 @@ pub mod backtrace;
 pub mod condvar;
 pub mod io;
 pub mod mutex;
+pub mod parking_lot;
 pub mod parking_lot_core;
 pub mod poison;
 pub mod remutex;

src/libstd/sys_common/parking_lot/elision.rs

@@ -0,0 +1,166 @@
+// Copyright 2016 Amanieu d'Antras
+//
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+// http://opensource.org/licenses/MIT>, at your option. This file may not be
+// copied, modified, or distributed except according to those terms.
+
+use sync::atomic::AtomicUsize;
+
+// Extension trait to add lock elision primitives to atomic types
+pub trait AtomicElisionExt {
+    type IntType;
+
+    // Perform a compare_exchange and start a transaction
+    fn elision_acquire(
+        &self,
+        current: Self::IntType,
+        new: Self::IntType,
+    ) -> Result<Self::IntType, Self::IntType>;
+    // Perform a compare_exchange and end a transaction
+    fn elision_release(
+        &self,
+        current: Self::IntType,
+        new: Self::IntType,
+    ) -> Result<Self::IntType, Self::IntType>;
+}
+
+// Indicates whether the target architecture supports lock elision
+#[inline]
+pub fn have_elision() -> bool {
+    cfg!(any(target_arch = "x86", target_arch = "x86_64"))
+}
+
+// This implementation is never actually called because it is guarded by
+// have_elision().
+#[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
+impl AtomicElisionExt for AtomicUsize {
+    type IntType = usize;
+
+    #[inline]
+    fn elision_acquire(&self, _: usize, _: usize) -> Result<usize, usize> {
+        unreachable!();
+    }
+
+    #[inline]
+    fn elision_release(&self, _: usize, _: usize) -> Result<usize, usize> {
+        unreachable!();
+    }
+}
+
+#[cfg(target_arch = "x86")]
+impl AtomicElisionExt for AtomicUsize {
+    type IntType = usize;
+
+    #[inline]
+    fn elision_acquire(&self, current: usize, new: usize) -> Result<usize, usize> {
+        unsafe {
+            let prev: usize;
+            asm!("xacquire; lock; cmpxchgl $2, $1"
+                 : "={eax}" (prev), "+*m" (self)
+                 : "r" (new), "{eax}" (current)
+                 : "memory"
+                 : "volatile");
+            if prev == current {
+                Ok(prev)
+            } else {
+                Err(prev)
+            }
+        }
+    }
+
+    #[inline]
+    fn elision_release(&self, current: usize, new: usize) -> Result<usize, usize> {
+        unsafe {
+            let prev: usize;
+            asm!("xrelease; lock; cmpxchgl $2, $1"
+                 : "={eax}" (prev), "+*m" (self)
+                 : "r" (new), "{eax}" (current)
+                 : "memory"
+                 : "volatile");
+            if prev == current {
+                Ok(prev)
+            } else {
+                Err(prev)
+            }
+        }
+    }
+}
+
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "32"))]
+impl AtomicElisionExt for AtomicUsize {
+    type IntType = usize;
+
+    #[inline]
+    fn elision_acquire(&self, current: usize, new: usize) -> Result<usize, usize> {
+        unsafe {
+            let prev: usize;
+            asm!("xacquire; lock; cmpxchgl $2, $1"
+                 : "={rax}" (prev), "+*m" (self)
+                 : "r" (new), "{rax}" (current)
+                 : "memory"
+                 : "volatile");
+            if prev == current {
+                Ok(prev)
+            } else {
+                Err(prev)
+            }
+        }
+    }
+
+    #[inline]
+    fn elision_release(&self, current: usize, new: usize) -> Result<usize, usize> {
+        unsafe {
+            let prev: usize;
+            asm!("xrelease; lock; cmpxchgl $2, $1"
+                 : "={rax}" (prev), "+*m" (self)
+                 : "r" (new), "{rax}" (current)
+                 : "memory"
+                 : "volatile");
+            if prev == current {
+                Ok(prev)
+            } else {
+                Err(prev)
+            }
+        }
+    }
+}
+
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+impl AtomicElisionExt for AtomicUsize {
+    type IntType = usize;
+
+    #[inline]
+    fn elision_acquire(&self, current: usize, new: usize) -> Result<usize, usize> {
+        unsafe {
+            let prev: usize;
+            asm!("xacquire; lock; cmpxchgq $2, $1"
+                 : "={rax}" (prev), "+*m" (self)
+                 : "r" (new), "{rax}" (current)
+                 : "memory"
+                 : "volatile");
+            if prev == current {
+                Ok(prev)
+            } else {
+                Err(prev)
+            }
+        }
+    }
+
+    #[inline]
+    fn elision_release(&self, current: usize, new: usize) -> Result<usize, usize> {
+        unsafe {
+            let prev: usize;
+            asm!("xrelease; lock; cmpxchgq $2, $1"
+                 : "={rax}" (prev), "+*m" (self)
+                 : "r" (new), "{rax}" (current)
+                 : "memory"
+                 : "volatile");
+            if prev == current {
+                Ok(prev)
+            } else {
+                Err(prev)
+            }
+        }
+    }
+}

src/libstd/sys_common/parking_lot/mod.rs

@@ -0,0 +1,4 @@
+
+pub mod raw_rwlock;
+pub mod raw_mutex;
+pub mod elision;

src/libstd/sys_common/parking_lot/raw_mutex.rs

@@ -0,0 +1,20 @@
+// Copyright 2016 Amanieu d'Antras
+//
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+// http://opensource.org/licenses/MIT>, at your option. This file may not be
+// copied, modified, or distributed except according to those terms.
+
+type U8 = u8;
+use super::super::parking_lot_core::UnparkToken;
+
+// UnparkToken used to indicate that that the target thread should attempt to
+// lock the mutex again as soon as it is unparked.
+pub const TOKEN_NORMAL: UnparkToken = UnparkToken(0);
+
+// UnparkToken used to indicate that the mutex is being handed off to the target
+// thread directly without unlocking it.
+pub const TOKEN_HANDOFF: UnparkToken = UnparkToken(1);
+
+const LOCKED_BIT: U8 = 1;
+const PARKED_BIT: U8 = 2;