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Merge commit 382f70a877f0 from llvm-project (by Louis Dionne):

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Merge commit 382f70a877f0 from llvm-project (by Louis Dionne):

[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 ead8e4c081e5c4de4d508fc353f381457b058ca6)

Details

Provenance
dimAuthored on Jun 7 2024, 6:42 PM
Parents
rG960554869b20: sqlite3: Vendor import of sqlite3 3.46.0
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