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Align SingletonPtr data to 8 bytes, or use C++11 

Be more cautious about alignment - align the data within a SingletonPtr
to 8 bytes rather than 4. This could increase padding overhead by up
to 8 bytes, sadly, but we may need this alignment for correct operation.

Conditional check added for C++11 - if in use we can get correct minimal
alignment by using alignas(T).
pull/8354/head
Kevin Bracey 2018-09-10 11:10:41 +03:00
parent 199d1667ff
commit e7815c64ad
1 changed files with 7 additions and 2 deletions
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9
platform/SingletonPtr.h
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@ -125,8 +125,13 @@ struct SingletonPtr {
// This is zero initialized when in global scope
mutable T *_ptr;
// Force data to be 4 byte aligned
mutable uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
#if __cplusplus >= 201103L
// Align data appropriately
alignas(T) mutable char _data[sizeof(T)];
#else
// Force data to be 8 byte aligned
mutable uint64_t _data[(sizeof(T) + sizeof(uint64_t) - 1) / sizeof(uint64_t)];
#endif
};
#endif