1 files changed, 52 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/scudo/standalone/condition_variable_linux.cpp b/contrib/llvm-project/compiler-rt/lib/scudo/standalone/condition_variable_linux.cpp
new file mode 100644
index 000000000000..e6d9bd1771a4
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/scudo/standalone/condition_variable_linux.cpp
@@ -0,0 +1,52 @@
+//===-- condition_variable_linux.cpp ----------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "platform.h"
+
+#if SCUDO_LINUX
+
+#include "condition_variable_linux.h"
+
+#include "atomic_helpers.h"
+
+#include <limits.h>
+#include <linux/futex.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+namespace scudo {
+
+void ConditionVariableLinux::notifyAllImpl(UNUSED HybridMutex &M) {
+  const u32 V = atomic_load_relaxed(&Counter);
+  atomic_store_relaxed(&Counter, V + 1);
+
+  // TODO(chiahungduan): Move the waiters from the futex waiting queue
+  // `Counter` to futex waiting queue `M` so that the awoken threads won't be
+  // blocked again due to locked `M` by current thread.
+  if (LastNotifyAll != V) {
+    syscall(SYS_futex, reinterpret_cast<uptr>(&Counter), FUTEX_WAKE_PRIVATE,
+            INT_MAX, nullptr, nullptr, 0);
+  }
+
+  LastNotifyAll = V + 1;
+}
+
+void ConditionVariableLinux::waitImpl(HybridMutex &M) {
+  const u32 V = atomic_load_relaxed(&Counter) + 1;
+  atomic_store_relaxed(&Counter, V);
+
+  // TODO: Use ScopedUnlock when it's supported.
+  M.unlock();
+  syscall(SYS_futex, reinterpret_cast<uptr>(&Counter), FUTEX_WAIT_PRIVATE, V,
+          nullptr, nullptr, 0);
+  M.lock();
+}
+
+} // namespace scudo
+
+#endif // SCUDO_LINUX