================ @@ -327,6 +464,54 @@ a discriminator determined as follows: is ``ptrauth_blend_discriminator(&x, discriminator)``; see `ptrauth_blend_discriminator`_. +Non-triviality from address diversity ++++++++++++++++++++++++++++++++++++++ + +Address diversity must impose additional restrictions in order to allow the +implementation to correctly copy values. In C++, a type qualified with address +diversity is treated like a class type with non-trivial copy/move constructors +and assignment operators, with the usual effect on containing classes and +unions. C does not have a standard concept of non-triviality, and so we must +describe the basic rules here, with the intention of imitating the emergent +rules of C++: + +- A type may be **non-trivial to copy**. + +- A type may also be **illegal to copy**. Types that are illegal to copy are + always non-trivial to copy. + +- A type may also be **address-sensitive**. + +- A type qualified with a ``ptrauth`` qualifier that requires address diversity + is non-trivial to copy and address-sensitive. + +- An array type is illegal to copy, non-trivial to copy, or address-sensitive + if its element type is illegal to copy, non-trivial to copy, or + address-sensitive, respectively. + +- A struct type is illegal to copy, non-trivial to copy, or address-sensitive + if it has a field whose type is illegal to copy, non-trivial to copy, or + address-sensitive, respectively. + +- A union type is both illegal and non-trivial to copy if it has a field whose + type is non-trivial or illegal to copy. + +- A union type is address-sensitive if it has a field whose type is ---------------- AaronBallman wrote:
Should we say anything about lambdas (or blocks) which capture something that's illegal to copy, etc? https://github.com/llvm/llvm-project/pull/152596 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
