Implement epoll shim
This PR:
- implemented non-blocking ``epoll`` for #3448 . The design for this PR is documented in https://hackmd.io/`@tiif/SJatftrH0` .
- renamed FileDescriptor to FileDescriptionRef
- assigned an ID to every file description
Borrow tracking: remove the concept of a call ID
Turns out this is not needed any more ever since we started tracking the `protected_tags` list in the per-frame state.
Also thanks to `@JoJoDeveloping` for inspiring me to even consider this possibility. :)
miri: make vtable addresses not globally unique
Miri currently gives vtables a unique global address. That's not actually matching reality though. So this PR enables Miri to generate different addresses for the same type-trait pair.
To avoid generating an unbounded number of `AllocId` (and consuming unbounded amounts of memory), we use the "salt" technique that we also already use for giving constants non-unique addresses: the cache is keyed on a "salt" value n top of the actually relevant key, and Miri picks a random salt (currently in the range `0..16`) each time it needs to choose an `AllocId` for one of these globals -- that means we'll get up to 16 different addresses for each vtable. The salt scheme is integrated into the global allocation deduplication logic in `tcx`, and also used for functions and string literals. (So this also fixes the problem that casting the same function to a fn ptr over and over will consume unbounded memory.)
r? `@saethlin`
Fixes https://github.com/rust-lang/miri/issues/3737
miri-script: use --remap-path-prefix to print errors relative to the right root
Inspired by https://github.com/rust-lang/rust-clippy/pull/13232, this makes it so that when cargo-miri fails to build, `./miri check` will print errors with paths like `cargo-miri/src/setup.rs`. That means we can get rid of the miri-symlink-hacks and instead tell RA to just always invoke the `./miri clippy` script just once, in the root.
This means that we can no longer share a target dir between cargo-miri and miri as the RUSTFLAGS are different to crates that are shared in the dependency tree need to be built twice with two different flags. `miri-script` hence now has to set the MIRI environment variable to tell the `cargo miri setup` invocation where to find Miri.
I also made it so that errors in miri-script itself are properly shown in RA, for which the `./miri` shell wrapper needs to set the right flags.
Apply "polymorphization at home" to RawVec
The idea here is to move all the logic in RawVec into functions with explicit size and alignment parameters. This should eliminate all the fussing about how tweaking RawVec code produces large swings in compile times.
This uncovered https://github.com/rust-lang/rust-clippy/issues/12979, so I've modified the relevant test in a way that tries to preserve the spirit of the test without tripping the ICE.
Promote aarch64-apple-darwin to Tier 1
This promotes aarch64-apple-darwin to Tier 1 status as per rust-lang/rfcs#3671 and tracking issue #73908. Not sure what else is necessary for this to impement the aforementioned RFC, however I figured I'd try. I did read in previous issues and PRs that the necessary infrastructure was already in place for the aarch64-apple-darwin target, and the RFC mentions the same. So this should be all thats necessary in order for the target to be promoted.
This is a recreation of my previous PR because I accidentally did an incorrect git rebase which caused unnecessary changes to various commit SHAs. So this PR is a recreation of my previous PR without said stumble. My bad.
