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[libc++][NFC] Rewrite function call on two lines for clarity (#79141) Previously, there was a ternary conditional with a less-than comparison appearing inside a template argument, which was really confusing because of the <...> of the function template. This patch rewrites the same statement on two lines for clarity. Merge commit d129ea8d2fa3 from llvm-project (by Vitaly Buka): [libcxx] Align `__recommend() + 1` by __endian_factor (#90292) This is detected by asan after #83774 Allocation size will be divided by `__endian_factor` before storing. If it's not aligned, we will not be able to recover allocation size to pass into `__alloc_traits::deallocate`. we have code like this ``` auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1); __p = __allocation.ptr; __set_long_cap(__allocation.count); void __set_long_cap(size_type __s) _NOEXCEPT { __r_.first().__l.__cap_ = __s / __endian_factor; __r_.first().__l.__is_long_ = true; } size_type __get_long_cap() const _NOEXCEPT { return __r_.first().__l.__cap_ * __endian_factor; } inline ~basic_string() { __annotate_delete(); if (__is_long()) __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap()); } ``` 1. __recommend() -> even size 2. `std::__allocate_at_least(__alloc(), __recommend(__sz) + 1)` - > not even size 3. ` __set_long_cap() `- > lose one bit of size for __endian_factor == 2 (see `/ __endian_factor`) 4. `__alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap())` -> uses even size (see `__get_long_cap`) This should fix incorrect deallocation sizes for some instances of std::string. Memory profiling or debugging tools like AddressSanitizer, LeakSanitizer or TCMalloc could then complain about the the size passed to a deallocation not matching the size originally passed to the allocation. Reported by: Aliaksei Kandratsenka <alkondratenko@gmail.com> PR: 279560 MFC after: 3 days |
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