As someone that uses pointer tagging, I must point out that this article is insufficiently defensive.
I've done my own exploration of what I can get away with across 64-bit x86 and ARM in this regard. It has been a while but the maximum number of bits that are reliably taggable across all environments and use cases that I have been able to determine is six. Can you get away with more? Probably yes, but there are identifiable environments where it will explode if you do so. That may not apply to your use case.
I've done my own exploration of what I can get away with across 64-bit x86 and ARM in this regard. It has been a while but the maximum number of bits that are reliably taggable across all environments and use cases that I have been able to determine is six. Can you get away with more? Probably yes, but there are identifiable environments where it will explode if you do so. That may not apply to your use case.
Reliable pointer tagging is not trivial.