[libcxx-commits] [libcxx] [libc++][hardening] Use bounded iterators in std::vector and std::string (PR #78929)

[Louis Dionne via libcxx-commits]

================
@@ -798,10 +806,30 @@ private:
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __append(size_type __n);
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __append(size_type __n, const_reference __x);
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator __make_iter(pointer __p) _NOEXCEPT {
+#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
+    // Bound the iterator according to the capacity, rather than the size.
+    // Resizing a vector up to the capacity will not invalidate iterators, so,
+    // Without a way to update all live iterators on resize, we must
----------------
ldionne wrote:

```suggestion
    // Resizing a vector up to the capacity will not invalidate iterators, so
    // without a way to update all live iterators on resize, we must
```

https://github.com/llvm/llvm-project/pull/78929