20e4c80fbe
This is a reland of f5e261aaf65cdf2eb903cdf40d651846be44f447 This CL disables RTC_NO_UNIQUE_ADDRESS on MSan builds since there have been some issues. Original change's description: > Introduce RTC_NO_UNIQUE_ADDRESS. > > This macro introduces the possibility to suggest the compiler that a > data member doesn't need an address different from other non static > data members. > > The usage of a macro is to maintain portability since at the moment > the attribute [[no_unique_address]] is only supported by clang > with at least -std=c++11 but it should be supported by all the > compilers starting from C++20. > > Bug: webrtc:11495 > Change-Id: I9f12b67b4422a2749649eaa6b004a67d5fd572d8 > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/173331 > Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> > Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> > Cr-Commit-Position: refs/heads/master@{#32246} Bug: webrtc:11495, webrtc:12218 Change-Id: I4e6c7cc37d3daffad2407c9a2acfa897fa5b426a Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/189968 Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Cr-Commit-Position: refs/heads/master@{#32668}
39 lines
1.7 KiB
C++
39 lines
1.7 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.
|
|
//
|
|
// TODO(bugs.webrtc.org/12218): Re-enable on MSan builds.
|
|
#if !defined(__SANITIZE_MEMORY__) && \
|
|
((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_
|