Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/libunwind/src/RWMutex.hpp

@@ -0,0 +1,77 @@
+//===----------------------------- Registers.hpp --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//
+// Abstract interface to shared reader/writer log, hiding platform and
+// configuration differences.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __RWMUTEX_HPP__
+#define __RWMUTEX_HPP__
+
+#if defined(_WIN32)
+#include <windows.h>
+#elif !defined(_LIBUNWIND_HAS_NO_THREADS)
+#include <pthread.h>
+#endif
+
+namespace libunwind {
+
+#if defined(_LIBUNWIND_HAS_NO_THREADS)
+
+class _LIBUNWIND_HIDDEN RWMutex {
+public:
+  bool lock_shared() { return true; }
+  bool unlock_shared() { return true; }
+  bool lock() { return true; }
+  bool unlock() { return true; }
+};
+
+#elif defined(_WIN32)
+
+class _LIBUNWIND_HIDDEN RWMutex {
+public:
+  bool lock_shared() {
+    AcquireSRWLockShared(&_lock);
+    return true;
+  }
+  bool unlock_shared() {
+    ReleaseSRWLockShared(&_lock);
+    return true;
+  }
+  bool lock() {
+    AcquireSRWLockExclusive(&_lock);
+    return true;
+  }
+  bool unlock() {
+    ReleaseSRWLockExclusive(&_lock);
+    return true;
+  }
+
+private:
+  SRWLOCK _lock = SRWLOCK_INIT;
+};
+
+#else
+
+class _LIBUNWIND_HIDDEN RWMutex {
+public:
+  bool lock_shared() { return pthread_rwlock_rdlock(&_lock) == 0; }
+  bool unlock_shared() { return pthread_rwlock_unlock(&_lock) == 0; }
+  bool lock() { return pthread_rwlock_wrlock(&_lock) == 0; }
+  bool unlock() { return pthread_rwlock_unlock(&_lock) == 0; }
+
+private:
+  pthread_rwlock_t _lock = PTHREAD_RWLOCK_INITIALIZER;
+};
+
+#endif
+
+} // namespace libunwind
+
+#endif // __RWMUTEX_HPP__