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[Runtime] Remove all use of read/write locks.

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Read/write locks are not as good as you'd think; a simple mutex is better in
almost all cases.

rdar://90776105
This commit is contained in:
Alastair Houghton
2022-03-29 16:03:07 +01:00
parent 0cf687aa2b
commit 66b9d21000
11 changed files with 28 additions and 1072 deletions
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28
include/swift/Runtime/MutexPThread.h
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@@ -27,8 +27,6 @@
namespace swift {
typedef pthread_rwlock_t ReadWriteLockHandle;
#if HAS_OS_UNFAIR_LOCK
typedef os_unfair_lock MutexHandle;
#else
@@ -41,10 +39,8 @@ typedef pthread_mutex_t MutexHandle;
// results in a reinterpret_cast which violates constexpr.
// WASI currently doesn't support threading/locking at all.
#define SWIFT_MUTEX_SUPPORTS_CONSTEXPR 0
#define SWIFT_READWRITELOCK_SUPPORTS_CONSTEXPR 0
#else
#define SWIFT_MUTEX_SUPPORTS_CONSTEXPR 1
#define SWIFT_READWRITELOCK_SUPPORTS_CONSTEXPR 1
#endif
/// PThread low-level implementation that supports Mutex
@@ -114,30 +110,6 @@ inline bool MutexPlatformHelper::try_lock(os_unfair_lock &lock) {
#endif
/// PThread low-level implementation that supports ReadWriteLock
/// found in Mutex.h
///
/// See ReadWriteLock
struct ReadWriteLockPlatformHelper {
#if SWIFT_READWRITELOCK_SUPPORTS_CONSTEXPR
static constexpr
#else
static
#endif
ReadWriteLockHandle
staticInit() {
return PTHREAD_RWLOCK_INITIALIZER;
};
static void init(ReadWriteLockHandle &rwlock);
static void destroy(ReadWriteLockHandle &rwlock);
static void readLock(ReadWriteLockHandle &rwlock);
static bool try_readLock(ReadWriteLockHandle &rwlock);
static void readUnlock(ReadWriteLockHandle &rwlock);
static void writeLock(ReadWriteLockHandle &rwlock);
static bool try_writeLock(ReadWriteLockHandle &rwlock);
static void writeUnlock(ReadWriteLockHandle &rwlock);
};
}
#endif