os-rust/compiler/rustc_span
bors aa01891700 Auto merge of #99420 - RalfJung:vtable, r=oli-obk
make vtable pointers entirely opaque

This implements the scheme discussed in https://github.com/rust-lang/unsafe-code-guidelines/issues/338: vtable pointers should be considered entirely opaque and not even readable by Rust code, similar to function pointers.

- We have a new kind of `GlobalAlloc` that symbolically refers to a vtable.
- Miri uses that kind of allocation when generating a vtable.
- The codegen backends, upon encountering such an allocation, call `vtable_allocation` to obtain an actually dataful allocation for this vtable.
- We need new intrinsics to obtain the size and align from a vtable (for some `ptr::metadata` APIs), since direct accesses are UB now.

I had to touch quite a bit of code that I am not very familiar with, so some of this might not make much sense...
r? `@oli-obk`
2022-07-22 01:33:49 +00:00
..
src Auto merge of #99420 - RalfJung:vtable, r=oli-obk 2022-07-22 01:33:49 +00:00
Cargo.toml Update sha1, sha2, and md5 dependencies 2022-02-13 15:29:01 -06:00