[saagarjha]

> For languages that can express unforgeable pointers as first-class concept, that is indeed a very attractive, fine-grained approach. Unfortunately bringing that to languages like C/C++/Rust is a different matter altogether.

The semantics of these languages aren’t incompatible with unforgeable references, though: it generally works in practice, but it’s technically undefined to create pointers out of thin air. Why can’t we take advantage of the standard here to disallow illegally created references? (Which, as I understand it, many other vendors are already beginning to do with e.g. pointer authentication and memory tagging.)

[steven_is_false]

It's slow. You should read up on the challenges of implementing memcpy in C emulated on Java. Basically you have to manually implement paging.