diff -r 000000000000 -r 6474c204b198 tools/profiler/LulRWLock.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/profiler/LulRWLock.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,93 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Assertions.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/NullPtr.h"
+
+#include "LulRWLock.h"
+
+
+namespace lul {
+
+// An implementation for targets where libpthread does provide
+// pthread_rwlock_t.  These are straight wrappers around the
+// equivalent pthread functions.
+
+#if defined(LUL_OS_linux)
+
+LulRWLock::LulRWLock() {
+  mozilla::DebugOnly<int> r = pthread_rwlock_init(&mLock, nullptr);
+  MOZ_ASSERT(!r);
+}
+
+LulRWLock::~LulRWLock() {
+  mozilla::DebugOnly<int>r = pthread_rwlock_destroy(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+void
+LulRWLock::WrLock() {
+  mozilla::DebugOnly<int>r = pthread_rwlock_wrlock(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+void
+LulRWLock::RdLock() {
+  mozilla::DebugOnly<int>r = pthread_rwlock_rdlock(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+void
+LulRWLock::Unlock() {
+  mozilla::DebugOnly<int>r = pthread_rwlock_unlock(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+
+// An implementation for cases where libpthread does not provide
+// pthread_rwlock_t.  Currently this is a kludge in that it uses
+// normal mutexes, resulting in the following limitations: (1) at most
+// one reader is allowed at once, and (2) any thread that tries to
+// read-acquire the lock more than once will deadlock.  (2) could be
+// avoided if it were possible to use recursive pthread_mutex_t's.
+
+#elif defined(LUL_OS_android)
+
+LulRWLock::LulRWLock() {
+  mozilla::DebugOnly<int> r = pthread_mutex_init(&mLock, nullptr);
+  MOZ_ASSERT(!r);
+}
+
+LulRWLock::~LulRWLock() {
+  mozilla::DebugOnly<int>r = pthread_mutex_destroy(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+void
+LulRWLock::WrLock() {
+  mozilla::DebugOnly<int>r = pthread_mutex_lock(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+void
+LulRWLock::RdLock() {
+  mozilla::DebugOnly<int>r = pthread_mutex_lock(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+void
+LulRWLock::Unlock() {
+  mozilla::DebugOnly<int>r = pthread_mutex_unlock(&mLock);
+  MOZ_ASSERT(!r);
+}
+
+
+#else
+# error "Unsupported OS"
+#endif
+
+} // namespace lul