Describe and use CStr literals in CStr and CString docs
Mention CStr literals in the description of both types, and use them in some of the code samples for CStr. This is intended to make C string literals more discoverable.
Additionally, I don't think the orange "This example is not tested" warnings are very encouraging, so I have made the examples on `CStr` build.
coverage: Clean up creation of MC/DC condition bitmaps
This PR improves the code for creating and initializing [MC/DC](https://en.wikipedia.org/wiki/Modified_condition/decision_coverage) condition bitmap variables, as introduced by #123409 and modified by #124255.
- The condition bitmap variables are now created eagerly at the start of per-function codegen, via a new `init_coverage` method in `CoverageInfoBuilderMethods`. This avoids having to retroactively create the bitmaps while doing codegen for an individual coverage statement.
- As a result, we can now create and initialize those bitmaps using existing safe APIs, instead of having to perform our own unsafe call to `llvm::LLVMBuildAlloca`.
- This PR also tweaks the way we count the number of condition bitmaps needed, by tracking the total number of bitmaps needed (max depth + 1), instead of only tracking the maximum depth. This reduces the potential for subtle off-by-one confusion.
default_alloc_error_hook: explain difference to default __rdl_oom in alloc
Though I'm not sure if that is really the reason that this code is duplicated. On no_std it may already be possible to call user-defined code on allocation failure.
Implement ptr_as_ref_unchecked
Implementation of #122034.
Prefixed the feature name with `ptr_` for clarity.
Linked const-unstability to #91822, so the post there should probably be updated to mentions the 3 new methods when/if this PR is merged.
Rollup of 6 pull requests
Successful merges:
- #124461 (handle the targets that are missing in stage0)
- #124492 (Generalize `adjust_from_tcx` for `Allocation`)
- #124588 (Use `ObligationCtxt` in favor of `TraitEngine` in many more places)
- #124612 (Add support for inputing via stdin with run-make-support)
- #124613 (Allow fmt to run on rmake.rs test files)
- #124649 (Fix HorizonOS build broken by #124210)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix HorizonOS build broken by #124210
HorizonOS (for the Tier-3 target `armv6k-nintendo-3ds`) does not support `dirfd()`, as many other similar targets.
Allow fmt to run on rmake.rs test files
As discussed with `@jieyouxu,` `rmake.rs` from the `run-make` testsuite would benefit from being formatted as well.
Only thing needed to be done for it to work: allow support for `!` in our `rustfmt.toml` file parsing.
r? `@onur-ozkan`
Add support for inputing via stdin with run-make-support
This PR adds the facility to set a input bytes that will be passed via the standard input.
This is useful for testing `rustc -` (and soon `rustdoc -`).
In #124611 took the approach of having a dedicated `run` method but it is not very convenient to use and would necessitate many functions, one for success, one for fail, ...
Instead this PR takes a different approach and allows setting the input bytes as if it were a parameter and when calling the (now custom) `output` function, we write the input bytes into stdin. I think this gives us maximum flexibility in the implementation and a simple interface for users.
To test this new logic I ported `tests/run-make/stdin-non-utf8/` to an `rmake.rs` one.
r? `@jieyouxu`
Generalize `adjust_from_tcx` for `Allocation`
Previously, `adjust_from_tcx` would take an `Allocation` and "adjust allocation from the ones in `tcx` to a custom Machine instance [...]".
This PR generalizes this so the Machine instance can also determine the `Bytes` type of the output `Allocation`.
r? `@RalfJung`
handle the targets that are missing in stage0
During sanity checks, we search for target names to determine if they exist in the compiler's built-in target list (`rustc --print target-list`). While a target name may be present in the stage2 compiler, it might not yet be included in stage0. This PR handles that difference.
Follow-up of https://github.com/rust-lang/rust/pull/123546
`rustc_expand` cleanups
Some cleanups I made while looking through this code. Nothing that requires any real domain-specific knowledge about this crate.
r? ````@michaelwoerister````
library/std: Remove unused `gimli-symbolize` feature
library/backtrace also declares a feature called `gimli-symbolize` which appear used, but the feature in std with the same name is unused, so remove it.
String.truncate comment microfix (greater or equal)
String.truncate calls Vec.truncate, in turn, and that states "is greater or equal to". Beside common sense.
deref patterns: impl `DerefPure` for more std types
Context: [deref patterns](https://github.com/rust-lang/rust/issues/87121). The requirements of `DerefPure` aren't precise yet, but these types unambiguously satisfy them.
Interestingly, a hypothetical `impl DerefMut for Cow` that does a `Clone` would *not* be eligible for `DerefPure` if we allow mixing deref patterns with normal patterns. If the following is exhaustive then the `DerefMut` would cause UB:
```rust
match &mut Cow::Borrowed(&()) {
Cow::Owned(_) => ..., // Doesn't match
deref!(_x) if false => ..., // Causes the variant to switch to `Owned`
Cow::Borrowed(_) => ..., // Doesn't match
// We reach unreachable
}
```
It is currently an enum and the `tts` and `idx` fields are repeated
across the two variants.
This commit splits it into a struct `Frame` and an enum `FrameKind`, to
factor out the duplication. The commit also renames `Frame::new` as
`Frame::new_delimited` and adds `Frame::new_sequence`. I.e. both
variants now have a constructor.
Control flow never gets past the end of the `ExpandResult::Retry` match
arm, due to the `span_bug` and the `continue`. Therefore, the code after
the match can only be reached from the `ExpandResult::Ready` arm.
This commit moves that code after the match into the
`ExpandResult::Ready` arm, avoiding the need for the `continue` in the
`ExpandResult::Retry` arm.
