Thiago Macieira 309dacedac Atomics: remove requirement for alignment equality with plain types ... This was originally added so that you could replace a T with QAtomicInteger<T> in the same class and still keep ABI. However, for legacy reasons, on 32-bit x86, types larger than 4 bytes keep an old 1990s alignment of only 4 bytes, but modern std::atomic<T> for those 8- byte types enforces an alignment of 8 bytes. Therefore, the requirement to keep alignment is not possible to guarantee. In other words: you may not replace T with QAtomicInteger<T> or std::atomic<T> and assume no ABI breakages in all platforms. This is a requirement to implement atomicity. An 8-byte type aligned to only a 4-byte boundary could cross a 16-byte boundary or, worse, cross a cacheline boundary. Crossing the 16-byte boundary could be bad on some processors, but crossing the cacheline boundary (addresses ending in 0x3C, 0x7C, 0xCC and 0xFC, or 4 out of 64 possible addresses or 6.25%) is always bad: the CPUs cannot guarantee an atomic load or store operation. See also <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71660>. Task-number: QTBUG-67858 Change-Id: If90a92b041d3442fa0a4fffd15283e4615474582 Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>		2018-04-24 17:36:42 +00:00
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char	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
char16_t	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
char32_t	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
int	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
long	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
qlonglong	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
qptrdiff	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
quintptr	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
qulonglong	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
schar	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
short	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
uchar	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
uint	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
ulong	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
ushort	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
wchar_t	Add missing fetchAndXxx methods to atomic classes based on std::atomic	2015-03-05 00:05:00 +00:00
qatomicinteger.pri	Remove all the atomic code besides MSVC and std::atomic	2016-01-19 23:41:52 +00:00
qatomicinteger.pro	Remove all the atomic code besides MSVC and std::atomic	2016-01-19 23:41:52 +00:00
tst_qatomicinteger.cpp	Atomics: remove requirement for alignment equality with plain types	2018-04-24 17:36:42 +00:00