src/base/test/clang_coverage.cc

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/test/clang_coverage.h"

#include "base/no_destructor.h"
#include "base/synchronization/lock.h"

extern "C" int __llvm_profile_dump(void);

namespace base {

void WriteClangCoverageProfile() {
  // __llvm_profile_dump() guarantees that it will not dump coverage information
  // if it is being called twice or more. However, it is not thread safe, as it
  // is supposed to be called from atexit() handler rather than being called
  // directly from random places. Since we have to call it ourselves, we must
  // ensure thread safety in order to prevent duplication of coverage counters.
  static base::NoDestructor<base::Lock> lock;
  base::AutoLock auto_lock(*lock);
  __llvm_profile_dump();
}

}  // namespace base