webrtc/rtc_base/system/no_unique_address.h
Mirko Bonadei 90776cb0ef Enable RTC_NO_UNIQUE_ADDRESS on MSan builds.
The issue with MSan has been fixed in LLVM in
https://reviews.llvm.org/D92727.

Bug: webrtc:12218
Change-Id: I73a4831d2ee544948c499ff06c65fe4ce6bee18c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/203266
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33064}
2021-01-23 14:07:28 +00:00

35 lines
1.6 KiB
C++

/*
* Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_SYSTEM_NO_UNIQUE_ADDRESS_H_
#define RTC_BASE_SYSTEM_NO_UNIQUE_ADDRESS_H_
// RTC_NO_UNIQUE_ADDRESS is a portable annotation to tell the compiler that
// a data member need not have an address distinct from all other non-static
// data members of its class.
// It allows empty types to actually occupy zero bytes as class members,
// instead of occupying at least one byte just so that they get their own
// address. There is almost never any reason not to use it on class members
// that could possibly be empty.
// The macro expands to [[no_unique_address]] if the compiler supports the
// attribute, it expands to nothing otherwise.
// Clang should supports this attribute since C++11, while other compilers
// should add support for it starting from C++20. Among clang compilers,
// clang-cl doesn't support it yet and support is unclear also when the target
// platform is iOS.
#if ((defined(__clang__) && !defined(_MSC_VER) && !defined(WEBRTC_IOS)) || \
__cplusplus > 201703L)
// NOLINTNEXTLINE(whitespace/braces)
#define RTC_NO_UNIQUE_ADDRESS [[no_unique_address]]
#else
#define RTC_NO_UNIQUE_ADDRESS
#endif
#endif // RTC_BASE_SYSTEM_NO_UNIQUE_ADDRESS_H_