[libcxx-commits] [libcxx] [libc++] Add support for bounded iterators in std::array (PR #110729)

[Louis Dionne via libcxx-commits]

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@@ -176,6 +176,12 @@
 // ABI impact: changes the iterator type of `vector` (except `vector<bool>`).
 // #define _LIBCPP_ABI_BOUNDED_ITERATORS_IN_VECTOR
 
+// Changes the iterator type of `array` to a bounded iterator that keeps track of whether it's within the bounds of the
+// container and asserts it on every dereference and when performing iterator arithmetic.
+//
+// ABI impact: changes the iterator type of `array`.
+// #define _LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY
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ldionne wrote:

We have to store the beginning of the array in addition to the pointer into the array itself. So there is in fact a downside (performance wise) to enabling this ABI configuration. My preference would be to be consistent with other similar ABI settings for hardening and *not* enable them by default in ABI v2.

https://github.com/llvm/llvm-project/pull/110729