// Copyright 2015 Google Inc. All rights reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef GTEST_BLACKBOX_H

#define GTEST_BLACKBOX_H

#include "mozilla/Attributes.h"

#if defined(_MSC_VER)

#include <intrin.h>

#endif // _MSC_VER

namespace mozilla {

#if defined(_MSC_VER)

char volatile* UseCharPointer(char volatile*);

MOZ_ALWAYS_INLINE_EVEN_DEBUG void* BlackBoxVoidPtr(void* aPtr) {

  aPtr = const_cast<char*>(UseCharPointer(reinterpret_cast<char*>(aPtr)));

  _ReadWriteBarrier();

  return aPtr;

}

#else

// See: https://youtu.be/nXaxk27zwlk?t=2441

MOZ_ALWAYS_INLINE_EVEN_DEBUG void* BlackBoxVoidPtr(void* aPtr) {

  // "g" is what we want here, but the comment in the Google

  // benchmark code suggests that GCC likes "i,r,m" better.

  // However, on Mozilla try server i,r,m breaks GCC but g

  // works in GCC, so using g for both clang and GCC.

  // godbolt.org indicates that g works already in GCC 4.9,

  // which is the oldest GCC we support at the time of this

  // code landing. godbolt.org suggests that this clearly

  // works is LLVM 5, but it's unclear if this inhibits

  // all relevant optimizations properly on earlier LLVM.

  asm volatile("" : "+g"(aPtr) : "g"(aPtr) : "memory");

  return aPtr;

}

#endif // _MSC_VER

template<class T>

MOZ_ALWAYS_INLINE_EVEN_DEBUG T* BlackBox(T* aPtr) {

  return static_cast<T*>(BlackBoxVoidPtr(aPtr));

}

Unexecuted instantiation: nsTString<char>* mozilla::BlackBox<nsTString<char> >(nsTString<char>*)

Unexecuted instantiation: bool* mozilla::BlackBox<bool>(bool*)

Unexecuted instantiation: nsTString<char16_t>* mozilla::BlackBox<nsTString<char16_t> >(nsTString<char16_t>*)

Unexecuted instantiation: nsTAutoStringN<char, 64ul>* mozilla::BlackBox<nsTAutoStringN<char, 64ul> >(nsTAutoStringN<char, 64ul>*)

Unexecuted instantiation: nsTAutoStringN<char16_t, 64ul>* mozilla::BlackBox<nsTAutoStringN<char16_t, 64ul> >(nsTAutoStringN<char16_t, 64ul>*)

} // namespace mozilla

#endif // GTEST_BLACKBOX_H