Generating the coverage map
@tmandry @wesleywiser
rustc now generates the coverage map and can support (limited)
coverage report generation, at the function level.
Example commands to generate a coverage report:
```shell
$ BUILD=$HOME/rust/build/x86_64-unknown-linux-gnu
$ $BUILD/stage1/bin/rustc -Zinstrument-coverage \
$HOME/rust/src/test/run-make-fulldeps/instrument-coverage/main.rs
$ LLVM_PROFILE_FILE="main.profraw" ./main
called
$ $BUILD/llvm/bin/llvm-profdata merge -sparse main.profraw -o main.profdata
$ $BUILD/llvm/bin/llvm-cov show --instr-profile=main.profdata main
```
r? @wesleywiser
Rust compiler MCP rust-lang/compiler-team#278
Relevant issue: #34701 - Implement support for LLVMs code coverage instrumentation
Make unreachable_unchecked a const fn
This PR makes `std::hint::unreachable_unchecked` a const fn so we can use it inside a const function.
r? @RalfJung
Fixes#53188.
rustc_metadata: Make crate loading fully speculative
Instead of reporting `span_err`s on the spot crate loading errors are now wrapped into the `CrateError` enum and returned, so they are reported only at the top level `resolve_crate` call, and not reported at all if we are resolving speculatively with `maybe_resolve_crate`.
As a result we can attempt loading crates for error recovery (e.g. import suggestions) without any risk of producing extra errors.
Also, this means better separation between error reporting and actual logic.
Fixes https://github.com/rust-lang/rust/issues/55103
Fixes https://github.com/rust-lang/rust/issues/56590
improper_ctypes_definitions: allow `Box`
Addresses https://github.com/rust-lang/rust/pull/72700#issuecomment-659449386.
This PR stops linting against `Box` in `extern "C" fn`s for the `improper_ctypes_definitions` lint - boxes are documented to be FFI-safe.
cc @alexcrichton @CryZe
Compare tagged/niche-filling layout and pick the best one
Finishes up #71045, and so fixes#63866.
cc @eddyb
r? @nikomatsakis (since @eddyb wrote the first commit)
intra-doc links: resolve modules in the type namespace
Fixes https://github.com/rust-lang/rust/issues/62830
Modules actually live in the type namespace, not all three, and it's not possible to clash a type with a module.
Add Arguments::as_str().
There exist quite a few macros in the Rust ecosystem which use `format_args!()` for formatting, but special case the one-argument case for optimization:
```rust
#[macro_export]
macro_rules! some_macro {
($s:expr) => { /* print &str directly, no formatting, no buffers */ };
($s:expr, $($tt:tt)*) => { /* use format_args to write to a buffer first */ }
}
```
E.g. [here](7a961f0fbe/src/macros.rs (L48-L58)), [here](20f9a9e223/src/macros.rs (L9-L17)), and [here](7b679cd6da/px4/src/logging.rs (L45-L52)).
The problem with these is that a forgotten argument such as in `some_macro!("{}")` will not be diagnosed, but just prints `"{}"`.
With this PR, it is possible to handle the no-arguments case separately *after* `format_args!()`, while simplifying the macro. Then these macros can give the proper error about a missing argument, just like `print!("{}")` does, while still using the same optimized implementation as before.
This is even more important with [RFC 2795](https://github.com/rust-lang/rfcs/pull/2795), to make sure `some_macro!("{some_variable}")` works as expected.
Fix MinGW `run-make-fulldeps` tests
`compiler-rt-works-on-mingw` and `libs-search-path` were not ran because `only-mingw` doesn't match any target.
Enabled and verified few ignored tests with `windows-gnu` toolchain. They are still ignored on MSVC since I'm not experienced with this target.
Make some Option methods const
Tracking issue: #67441
Constantify the following methods of `Option`:
- `as_ref`
- `is_some`
- `is_none`
- `iter` (not sure about this one, but it is possible, and will be useful when const traits are a thing)
cc @rust-lang/wg-const-eval @rust-lang/libs
This commit stops linting against `Box` in `extern "C" fn`s for the
`improper_ctypes_definitions` lint - boxes are documented to be
FFI-safe.
Signed-off-by: David Wood <david@davidtw.co>
When ran on Windows `cp` will follow symlink: `checkout/build/<target>/<stage>/lib/rustlib/src/rust`.
It points to `checkout` which means the test will get stuck in copying loop until there is no space left.
