Bump host compiler on x64 dist Linux to LLVM 17.0.2
17.0.0-rc3 had a bunch of miscompilations, and it's probably better in general not to use a RC version of LLVM long term on CI.
Reserved loses permissions too quickly.
Adding more fine-grained behavior of Reserved lets it lose
write permissions only temporarily.
Protected tags receive a read access on initialized locations.
Support getentropy on macOS as a foreign item
Prior this was always assumed to be accessed via `dlsym` shim, but in `std` I'm attempting to start [unconditionally linking](https://github.com/rust-lang/rust/pull/116319) to `getentropy` on macOS now that Rust's platform version support allows it.
This just moves the main logic of the previous `dlsym` handler into an eval context extension so it can be used via both call paths. The `dlsym` handler is still needed as `getrandom` uses it.
More accurately point to where default return type should go
When getting the "default return type" span, instead of pointing to the low span of the next token, point to the high span of the previous token. This:
1. Makes forming return type suggestions more uniform, since we expect them all in the same place.
2. Arguably makes labels easier to understand, since we're pointing to where the implicit `-> ()` would've gone, rather than the starting brace or the semicolon.
r? ```@estebank```
The word "active" is currently used in two different and confusing ways:
- `ACTIVE_FEATURES` actually means "available unstable features"
- `Features::active_features` actually means "features declared in the
crate's code", which can include feature within `ACTIVE_FEATURES` but
also others.
(This is also distinct from "enabled" features which includes declared
features but also some edition-specific features automatically enabled
depending on the edition in use.)
This commit changes the `Features::active_features` to
`Features::declared_features` which actually matches its meaning.
Likewise, `Features::active` becomes `Features::declared`.
Updates documentation for LLVM CFI support with recommended information
since the user can now rebuild and use both core and std with CFI
enabled using the Cargo build-std feature.
Remove wasm32-unknown-emscripten tests from CI
This builder tested the wasm32-unknown-emscripten target, which is tier 2 (and so not eligible for testing). In the recent beta [promotion](https://github.com/rust-lang/rust/pull/116362#issuecomment-1744960904), we ran into a problem with this target: emscripten doesn't support passing environment variables into the std environment, so we can't enable RUSTC_BOOTSTRAP for libtest in order to pass -Zunstable-options.
We worked around this for the beta/stable branches, but given this problem, and its tier 2 status, just dropping the target's tests entirely seems warranted. Downgrading to tier 3 may also be a good idea, but that is a separate conversation not proposed here.
