ef4d145057
[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
(cherry picked from commit
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