1 files changed, 136 insertions, 0 deletions
diff --git a/llvm/lib/Support/RWMutex.cpp b/llvm/lib/Support/RWMutex.cpp
new file mode 100644
index 0000000000000..5accf73e5f940
--- /dev/null
+++ b/llvm/lib/Support/RWMutex.cpp
@@ -0,0 +1,136 @@
+//===- RWMutex.cpp - Reader/Writer Mutual Exclusion Lock --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the llvm::sys::RWMutex class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/RWMutex.h"
+#include "llvm/Config/config.h"
+
+#if defined(LLVM_USE_RW_MUTEX_IMPL)
+using namespace llvm;
+using namespace sys;
+
+#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0
+// Define all methods as no-ops if threading is explicitly disabled
+
+RWMutexImpl::RWMutexImpl() = default;
+RWMutexImpl::~RWMutexImpl() = default;
+
+bool RWMutexImpl::lock_shared() { return true; }
+bool RWMutexImpl::unlock_shared() { return true; }
+bool RWMutexImpl::lock() { return true; }
+bool RWMutexImpl::unlock() { return true; }
+
+#else
+
+#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_RWLOCK_INIT)
+
+#include <cassert>
+#include <cstdlib>
+#include <pthread.h>
+
+// Construct a RWMutex using pthread calls
+RWMutexImpl::RWMutexImpl()
+{
+  // Declare the pthread_rwlock data structures
+  pthread_rwlock_t* rwlock =
+    static_cast<pthread_rwlock_t*>(safe_malloc(sizeof(pthread_rwlock_t)));
+
+#ifdef __APPLE__
+  // Workaround a bug/mis-feature in Darwin's pthread_rwlock_init.
+  bzero(rwlock, sizeof(pthread_rwlock_t));
+#endif
+
+  // Initialize the rwlock
+  int errorcode = pthread_rwlock_init(rwlock, nullptr);
+  (void)errorcode;
+  assert(errorcode == 0);
+
+  // Assign the data member
+  data_ = rwlock;
+}
+
+// Destruct a RWMutex
+RWMutexImpl::~RWMutexImpl()
+{
+  pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
+  assert(rwlock != nullptr);
+  pthread_rwlock_destroy(rwlock);
+  free(rwlock);
+}
+
+bool
+RWMutexImpl::lock_shared()
+{
+  pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
+  assert(rwlock != nullptr);
+
+  int errorcode = pthread_rwlock_rdlock(rwlock);
+  return errorcode == 0;
+}
+
+bool
+RWMutexImpl::unlock_shared()
+{
+  pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
+  assert(rwlock != nullptr);
+
+  int errorcode = pthread_rwlock_unlock(rwlock);
+  return errorcode == 0;
+}
+
+bool
+RWMutexImpl::lock()
+{
+  pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
+  assert(rwlock != nullptr);
+
+  int errorcode = pthread_rwlock_wrlock(rwlock);
+  return errorcode == 0;
+}
+
+bool
+RWMutexImpl::unlock()
+{
+  pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
+  assert(rwlock != nullptr);
+
+  int errorcode = pthread_rwlock_unlock(rwlock);
+  return errorcode == 0;
+}
+
+#else
+
+RWMutexImpl::RWMutexImpl() : data_(new MutexImpl(false)) { }
+
+RWMutexImpl::~RWMutexImpl() {
+  delete static_cast<MutexImpl *>(data_);
+}
+
+bool RWMutexImpl::lock_shared() {
+  return static_cast<MutexImpl *>(data_)->acquire();
+}
+
+bool RWMutexImpl::unlock_shared() {
+  return static_cast<MutexImpl *>(data_)->release();
+}
+
+bool RWMutexImpl::lock() {
+  return static_cast<MutexImpl *>(data_)->acquire();
+}
+
+bool RWMutexImpl::unlock() {
+  return static_cast<MutexImpl *>(data_)->release();
+}
+
+#endif
+#endif
+#endif