rust/library/std
joboet f3facf1175
std: refactor the TLS implementation
As discovered by Mara in #110897, our TLS implementation is a total mess. In the past months, I have simplified the actual macros and their expansions, but the majority of the complexity comes from the platform-specific support code needed to create keys and register destructors. In keeping with #117276, I have therefore moved all of the `thread_local_key`/`thread_local_dtor` modules to the `thread_local` module in `sys` and merged them into a new structure, so that future porters of `std` can simply mix-and-match the existing code instead of having to copy the same (bad) implementation everywhere. The new structure should become obvious when looking at `sys/thread_local/mod.rs`.

Unfortunately, the documentation changes associated with the refactoring have made this PR rather large. That said, this contains no functional changes except for two small ones:
* the key-based destructor fallback now, by virtue of sharing the implementation used by macOS and others, stores its list in a `#[thread_local]` static instead of in the key, eliminating one indirection layer and drastically simplifying its code.
* I've switched over ZKVM (tier 3) to use the same implementation as WebAssembly, as the implementation was just a way worse version of that

Please let me know if I can make this easier to review! I know these large PRs aren't optimal, but I couldn't think of any good intermediate steps.

@rustbot label +A-thread-locals
2024-06-15 17:47:35 +02:00
..
benches also test parts of std 2024-04-07 10:05:57 +02:00
src std: refactor the TLS implementation 2024-06-15 17:47:35 +02:00
tests Make PathBuf less Ok with adding UTF-16 then into_string 2024-06-12 01:00:21 -07:00
build.rs Move some expected cfgs to std build.rs as per Cargo recommandation 2024-05-23 16:08:31 +02:00
Cargo.toml Update backtrace to 0.3.73 2024-06-06 22:50:45 -07:00