llvm-project

d714a6c2 - Reland [MS][clang] Add support for vector deleting destructors (#170337)

Reland [MS][clang] Add support for vector deleting destructors (#170337) This reverts commit https://github.com/llvm/llvm-project/commit/54a4da9df6906b63878ad6d0ea6da3ed7d2d8432. MSVC supports an extension allowing to delete an array of objects via pointer whose static type doesn't match its dynamic type. This is done via generation of special destructors - vector deleting destructors. MSVC's virtual tables always contain a pointer to the vector deleting destructor for classes with virtual destructors, so not having this extension implemented causes clang to generate code that is not compatible with the code generated by MSVC, because clang always puts a pointer to a scalar deleting destructor to the vtable. As a bonus the deletion of an array of polymorphic object will work just like it does with MSVC - no memory leaks and correct destructors are called. This patch will cause clang to emit code that is compatible with code produced by MSVC but not compatible with code produced with clang of older versions, so the new behavior can be disabled via passing -fclang-abi-compat=21 (or lower). Fixes https://github.com/llvm/llvm-project/issues/19772