feat: Autocomplete Cargo-defined env vars in `env!` and `option_env!` (#12448)
Closes#12448
Important to know:
- Variables are taken from https://doc.rust-lang.org/cargo/reference/environment-variables.html and hardcoded as a const array.
- For the sake of simplicity I didn't include the autocompletion of `CARGO_BIN_EXE_<name>` and `OUT_DIR` since it would require information about build.rs and binary name. If somebody knows an easy way of obtaining them I can add those vars as well :)
Interpret EH actions properly
The EH actions stored in the LSDA follows the format of GCC except table (even for LLVM-generated code). An missing action in the table is the encoding for `Terminate`, see https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/libsupc%2B%2B/eh_personality.cc#L522-L526.
The currently code interprets it as `None`, as a workaround for #35011, an issue that seems to occur in LLVM 3.7 and not after 3.9. These are very old versions of LLVM and we don't support them anymore, so remove this workaround and interpret them properly.
Note that LLVM currently does not emit any `Terminate` actions, but GCC does. Although GCC backend currently doesn't do unwinding, removing it preemptively would prevent future developers from wasting time to figure out what's wrong.
``@rustbot`` label: +T-compiler
Migrate `codegen_ssa` to diagnostics structs - [Part 1]
Initial migration of `codegen_ssa`. Going to split this crate migration in at least two PRs in order to avoid a huge PR and to quick off some questions around:
1. Translating messages from "external" crates.
2. Interfacing with OS messages.
3. Adding UI tests while migrating diagnostics.
_See comments below._
fs::get_path solarish version.
similar to linux, albeit there is no /proc/self notion on solaris
based system thus flattening the difference for simplification sake.
Warn about safety of `fetch_update`
Specifically as it relates to the ABA problem.
`fetch_update` is a useful function, and one that isn't provided by, say, C++. However, this does not mean the function is magic. It is implemented in terms of `compare_exchange_weak`, and in particular, suffers from the ABA problem. See the following code, which is a naive implementation of `pop` in a lock-free queue:
```rust
fn pop(&self) -> Option<i32> {
self.front.fetch_update(Ordering::Relaxed, Ordering::Acquire, |front| {
if front == ptr::null_mut() {
None
}
else {
Some(unsafe { (*front).next })
}
}.ok()
}
```
This code is unsound if called from multiple threads because of the ABA problem. Specifically, suppose nodes are allocated with `Box`. Suppose the following sequence happens:
```
Initial: Queue is X -> Y.
Thread A: Starts popping, is pre-empted.
Thread B: Pops successfully, twice, leaving the queue empty.
Thread C: Pushes, and `Box` returns X (very common for allocators)
Thread A: Wakes up, sees the head is still X, and stores Y as the new head.
```
But `Y` is deallocated. This is undefined behaviour.
Adding a note about this problem to `fetch_update` should hopefully prevent users from being misled, and also, a link to this common problem is, in my opinion, an improvement to our docs on atomics.
Check uniqueness of impl items by trait item when applicable.
When checking uniqueness of item names in impl blocks, we currently use the same definition of hygiene as for toplevel items. This means that a plain item and one generated by a macro 2.0 do not collide.
This hygiene rule does not match with how impl items resolve to associated trait items. As a consequence, we misdiagnose the trait impls.
This PR proposes to consider that trait impl items are uses of the corresponding trait items during resolution, instead of checking for duplicates later. An error is emitted when a trait impl item is used twice.
There should be no stable breakage, since macros 2.0 are still unstable.
r? ``@petrochenkov``
cc ``@RalfJung``
Fixes https://github.com/rust-lang/rust/issues/71614.
Since 98f05a0282 and
b5963f07e6 removed color classes from sidebar
items, there's no need for the selectors to be so specific any more.
This commit does have to change `h1.fqn a` to just be `h1 a`, so that the
header link color selector is less specific than the typed link at the end.
Since #89506 made docblocks start at `h2`, the main page link header should
be the only h1 in the page now.
fix: reorder dyn bounds on render
Fixes#13368#13192 changed the order of dyn bounds, violating the [contract](3a69435af7/crates/hir-ty/src/display.rs (L896-L901)) with `write_bounds_like_dyn_trait()` on render. The projection bounds are expected to come right after the trait bound they are accompanied with.
Although the reordering procedure can be made a bit more efficient, I opted for relying only on the [invariants](3a69435af7/crates/hir-ty/src/lower.rs (L995-L998)) currently documented in `lower_dyn_trait()`. It's not the hottest path and dyn bounds tend to be short so I believe it shouldn't hurt performance noticeably.
Move lifetime resolution module to rustc_hir_analysis.
Now that lifetime resolution has been removed from it, this file has nothing to do in `rustc_resolve`. It's purpose is to compute Debruijn indices for lifetimes, so let's put it in type collection.
scoped threads: pass closure through MaybeUninit to avoid invalid dangling references
The `main` function defined here looks roughly like this, if it were written as a more explicit stand-alone function:
```rust
// Not showing all the `'lifetime` tracking, the point is that
// this closure might live shorter than `thread`.
fn thread(control: ..., closure: impl FnOnce() + 'lifetime) {
closure();
control.signal_done();
// A lot of time can pass here.
}
```
Note that `thread` continues to run even after `signal_done`! Now consider what happens if the `closure` captures a reference of lifetime `'lifetime`:
- The type of `closure` is a struct (the implicit unnameable closure type) with a `&'lifetime mut T` field. References passed to a function are marked with `dereferenceable`, which is LLVM speak for *this reference will remain live for the entire duration of this function*.
- The closure runs, `signal_done` runs. Then -- potentially -- this thread gets scheduled away and the main thread runs, seeing the signal and returning to the user. Now `'lifetime` ends and the memory the reference points to might be deallocated.
- Now we have UB! The reference that as passed to `thread` with the promise of remaining live for the entire duration of the function, actually got deallocated while the function still runs. Oops.
Long-term I think we should be able to use `ManuallyDrop` to fix this without `unsafe`, or maybe a new `MaybeDangling` type. I am working on an RFC for that. But in the mean time it'd be nice to fix this so that Miri with `-Zmiri-retag-fields` (which is needed for "full enforcement" of all the LLVM flags we generate) stops erroring on scoped threads.
Fixes https://github.com/rust-lang/rust/issues/101983
r? `@m-ou-se`
tools/remote-test-{server,client}: Use /data/local/tmp on Android
The /data/tmp directory does not exist, at least not on recent versions of Android, which currently leads to test failures on that platform. I checked a virtual device running AOSP master and a Nexus 5 running Android Marshmallow and on both devices the /data/tmp directory does not exist and /data/local/tmp does, so let's switch to /data/local/tmp.
Fix the sanitizer_scs_attr_check.rs test
The test is failing when targeting aarch64 Android. The intent appears to have been to look for a function attributes comment (or the absence of one) on the line preceding the function declaration. But this isn't quite possible with FileCheck and the test as written was looking for a line with `no_scs` after a line with `scs`, which doesn't appear in the output. Instead, match on the function attributes comment on the line following the demangled function name comment.
