SafeStack

[tera]

There's an interesting concept of safe stack:

It works by separating the program stack into two distinct regions: the safe stack and the unsafe stack. The safe stack stores return addresses, register spills, and local variables that are always accessed in a safe way, while the unsafe stack stores everything else. This separation ensures that buffer overflows on the unsafe stack cannot be used to overwrite anything on the safe stack.

Could this be used with Swift?

[AlexanderM (Alexander Momchilov)]

I'm no expert in this area, but I think so, but only for Swift call frames. It's kind of similar to the Async Context, which stores the values of local variables that live across await statements. (further reading)

Swift prioritizes fast interop with C, and that would only work if C stack frames were left intact. Contrast this with say, the Go approach, which uses a custom (resizable) stack per go-routine. It's great for their green thread scheduling, and frees you up to use any custom format you want (which doesn't have to match the C ABI at all, if you so wished) but it severely cripples performance when calling out to C functions (which is why you see their ecosystem "rewriting the world" in Go, including things like libc syscall wrappers, to avoid those calls to C).