diff options
Diffstat (limited to '')
-rw-r--r-- | library/std/src/sys/sgx/rwlock.rs | 78 |
1 files changed, 44 insertions, 34 deletions
diff --git a/library/std/src/sys/sgx/rwlock.rs b/library/std/src/sys/sgx/rwlock.rs index a97fb9ab0..d89de18ca 100644 --- a/library/std/src/sys/sgx/rwlock.rs +++ b/library/std/src/sys/sgx/rwlock.rs @@ -7,42 +7,45 @@ use crate::sys_common::lazy_box::{LazyBox, LazyInit}; use super::waitqueue::{ try_lock_or_false, NotifiedTcs, SpinMutex, SpinMutexGuard, WaitQueue, WaitVariable, }; -use crate::mem; +use crate::alloc::Layout; -pub struct RwLock { +struct AllocatedRwLock { readers: SpinMutex<WaitVariable<Option<NonZeroUsize>>>, writer: SpinMutex<WaitVariable<bool>>, } -pub(crate) type MovableRwLock = LazyBox<RwLock>; +pub struct RwLock { + inner: LazyBox<AllocatedRwLock>, +} -impl LazyInit for RwLock { +impl LazyInit for AllocatedRwLock { fn init() -> Box<Self> { - Box::new(Self::new()) + Box::new(AllocatedRwLock { + readers: SpinMutex::new(WaitVariable::new(None)), + writer: SpinMutex::new(WaitVariable::new(false)), + }) } } -// Check at compile time that RwLock size matches C definition (see test_c_rwlock_initializer below) -// -// # Safety -// Never called, as it is a compile time check. -#[allow(dead_code)] -unsafe fn rw_lock_size_assert(r: RwLock) { - unsafe { mem::transmute::<RwLock, [u8; 144]>(r) }; -} +// Check at compile time that RwLock's size and alignment matches the C definition +// in libunwind (see also `test_c_rwlock_initializer` in `tests`). +const _: () = { + let rust = Layout::new::<RwLock>(); + let c = Layout::new::<*mut ()>(); + assert!(rust.size() == c.size()); + assert!(rust.align() == c.align()); +}; impl RwLock { pub const fn new() -> RwLock { - RwLock { - readers: SpinMutex::new(WaitVariable::new(None)), - writer: SpinMutex::new(WaitVariable::new(false)), - } + RwLock { inner: LazyBox::new() } } #[inline] - pub unsafe fn read(&self) { - let mut rguard = self.readers.lock(); - let wguard = self.writer.lock(); + pub fn read(&self) { + let lock = &*self.inner; + let mut rguard = lock.readers.lock(); + let wguard = lock.writer.lock(); if *wguard.lock_var() || !wguard.queue_empty() { // Another thread has or is waiting for the write lock, wait drop(wguard); @@ -57,8 +60,9 @@ impl RwLock { #[inline] pub unsafe fn try_read(&self) -> bool { - let mut rguard = try_lock_or_false!(self.readers); - let wguard = try_lock_or_false!(self.writer); + let lock = &*self.inner; + let mut rguard = try_lock_or_false!(lock.readers); + let wguard = try_lock_or_false!(lock.writer); if *wguard.lock_var() || !wguard.queue_empty() { // Another thread has or is waiting for the write lock false @@ -71,9 +75,10 @@ impl RwLock { } #[inline] - pub unsafe fn write(&self) { - let rguard = self.readers.lock(); - let mut wguard = self.writer.lock(); + pub fn write(&self) { + let lock = &*self.inner; + let rguard = lock.readers.lock(); + let mut wguard = lock.writer.lock(); if *wguard.lock_var() || rguard.lock_var().is_some() { // Another thread has the lock, wait drop(rguard); @@ -86,9 +91,10 @@ impl RwLock { } #[inline] - pub unsafe fn try_write(&self) -> bool { - let rguard = try_lock_or_false!(self.readers); - let mut wguard = try_lock_or_false!(self.writer); + pub fn try_write(&self) -> bool { + let lock = &*self.inner; + let rguard = try_lock_or_false!(lock.readers); + let mut wguard = try_lock_or_false!(lock.writer); if *wguard.lock_var() || rguard.lock_var().is_some() { // Another thread has the lock false @@ -122,8 +128,9 @@ impl RwLock { #[inline] pub unsafe fn read_unlock(&self) { - let rguard = self.readers.lock(); - let wguard = self.writer.lock(); + let lock = &*self.inner; + let rguard = lock.readers.lock(); + let wguard = lock.writer.lock(); unsafe { self.__read_unlock(rguard, wguard) }; } @@ -158,8 +165,9 @@ impl RwLock { #[inline] pub unsafe fn write_unlock(&self) { - let rguard = self.readers.lock(); - let wguard = self.writer.lock(); + let lock = &*self.inner; + let rguard = lock.readers.lock(); + let wguard = lock.writer.lock(); unsafe { self.__write_unlock(rguard, wguard) }; } @@ -167,8 +175,9 @@ impl RwLock { #[inline] #[cfg_attr(test, allow(dead_code))] unsafe fn unlock(&self) { - let rguard = self.readers.lock(); - let wguard = self.writer.lock(); + let lock = &*self.inner; + let rguard = lock.readers.lock(); + let wguard = lock.writer.lock(); if *wguard.lock_var() == true { unsafe { self.__write_unlock(rguard, wguard) }; } else { @@ -201,6 +210,7 @@ pub unsafe extern "C" fn __rust_rwlock_wrlock(p: *mut RwLock) -> i32 { unsafe { (*p).write() }; return 0; } + #[cfg(not(test))] #[no_mangle] pub unsafe extern "C" fn __rust_rwlock_unlock(p: *mut RwLock) -> i32 { |