Use -Zmir-opt-level=0 in tests for MIR building
The mir-opt test suite currently defaults all tests in it to `-Zmir-opt-level=4`, so if a test is trying to test MIR _building_ not optimizations and it is in that directory, it _must_ override the default mir-opt-level.
Rollup of 9 pull requests
Successful merges:
- rust-lang/rust#144499 (ci: Begin running ui tests with `rust.debuginfo-level-tests=1`)
- rust-lang/rust#145790 (Improve dist for gnullvm hosts)
- rust-lang/rust#145792 (Use attribute name in message for "outer attr used as inner attr" errors)
- rust-lang/rust#145840 (rustc_codegen_ssa: More comprehensive RISC-V ELF flags)
- rust-lang/rust#145876 (Enable building/disting standard library in stage 0)
- rust-lang/rust#145887 (bootstrap: Don't panic if codegen-backends is set to empty)
- rust-lang/rust#145888 (platform-support: Fix LoongArch32 host column)
- rust-lang/rust#145892 (add a flag to codegen fn attrs for foreign items)
- rust-lang/rust#145901 (Fix typo in comment of library/alloc/src/raw_vec/mod.rs)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix typo in comment of library/alloc/src/raw_vec/mod.rs
Turn "any heap allocators" into "any heap allocator".
Shoutout to [Let's Read OSS](https://github.com/stoeckmann/lets-read-oss).
Enable building/disting standard library in stage 0
After the stage0 redesign, building a stage0 library no longer is a thing, because the stage0 compiler normally cannot build libstd anymore. However, there are valid use-cases for having the ability to quickly cross-compile libstd for different targets, when the stage0 compiler is e.g. a stable released version, and you want to cross-compile libstd from the same sources of that compiler.
This PR allows that, as long as you set `build.local-rebuild = true`, which promises bootstrap that the stage0 compiler actually comes from in-tree sources, and can thus compile libstd.
The change needed to enable this is very minimal, so I think that it is worth it to allow this use-case to work.
Fixes: https://github.com/rust-lang/rust/issues/145587
Fixes: https://github.com/rust-lang/rust/issues/145859
Related issue: https://github.com/rust-lang/rust/issues/94781
r? `@jieyouxu`
rustc_codegen_ssa: More comprehensive RISC-V ELF flags
This change implements more conformant, more comprehensive RISC-V ELF flags handling when generating certain object files directly from rustc.
* Use `"zca"` instead of `"c"`
The "Zca" extension (a subset of "C") is the minimal configuration for compressed instructions to set `EF_RISCV_RVC` flag.
* Set TSO flag from `"ztso"`
The "Ztso" extension denotes that the program depends on the RVTSO (Total Store Ordering) memory consistency model, which is stronger than the standard RVWMO (Weak Memory Ordering) consistency model and on ELF targets, we need to set `EF_RISCV_TSO` flag.
Improve dist for gnullvm hosts
LLVM tools cross-compilation has been fixed by rust-lang/rust#145763 and LLVM downloading from CI no longer causes build error, so let's enable them both.
ci: Begin running ui tests with `rust.debuginfo-level-tests=1`
To reduce risk of regressing on generating debuginfo e.g. in the form of ICE:s. This will also ensure that future ui tests work with different debuginfo levels. See https://github.com/rust-lang/rust/issues/61117.
When I looked at run time for different CI jobs, **x86_64-gnu-debug** was far from the bottleneck, so it should be fine to make it perform more work.
A handful of tests are failing so we need to force debuginfo=0 on those for now.
We'll start small with debuginfo=1. We'll step up to debuginfo=2 once most (all?) tests can handle debuginfo=1. There are more failures with debuginfo=2 than with debuginfo=1.
cg_llvm: Assert that LLVM range-attribute values don't exceed 128 bits
The underlying implementation of `LLVMCreateConstantRangeAttribute` assumes that each of `LowerWords` and `UpperWords` points to enough u64 values to define an integer of the specified bit-length, and will encounter UB if that is not the case.
Our safe wrapper function always passes pointers to `[u64; 2]` arrays, regardless of the bit-length specified. That's fine in practice, because scalar primitives never exceed 128 bits, but it is technically a soundness hole in a safe function.
We can close the soundness hole by explicitly asserting `size_bits <= 128`. This is effectively just a stricter version of the existing check that the value must be small enough to fit in `c_uint`.
---
This is a narrower version of the fix in rust-lang/rust#145846.
formatting_options: Make all methods `const`
Related to rust-lang/rust#118117.
Having `const fn`s that take a `mut &` was unstable until Rust 1.83 (see rust-lang/rust#129195). Because of this, not all methods on `FormattingOptions` were implemented as `const`. As this has been stabilized now, there is no reason not to have all methods `const`.
Thanks to `@Ternvein` for bringing this to my attention (see [1]).
r? `@m-ou-se` (As you were the reviewer for the original implementation – feel free to reroll if you are busy or if you aren't interested)
[1]: https://github.com/rust-lang/rust/issues/118117#issuecomment-2687470635
bootstrap: vendor `clippy_test_deps` too
This internal crate explicitly separates itself from the `rustc`
workspace, but it is needed for `./x test clippy` to work, including its
dependencies when building from a vendored `rustc-src` tarball.
Always build miri for the host in `x run miri`
Previously we were building Miri for the passed `--target`, which was wrong.
Fixes: https://github.com/rust-lang/rust/issues/145839
r? `@jieyouxu`
Losslessly optimize PNG files
Losslessly optimizes all of the PNG files in the repo. Done with:
```
oxipng -o max -a -s
oxipng -o max --zopfli -a -s
```
Update books
## rust-lang/nomicon
1 commits in 3ff384320598bbe8d8cfe5cb8f18f78a3a3e6b15..57ed4473660565d9357fcae176b358d7e8724ebf
2025-08-18 17:31:07 UTC to 2025-08-18 17:31:07 UTC
- Fix unknown field `author` error when building the book (rust-lang/nomicon#500)
## rust-lang/reference
11 commits in 59b8af811886313577615c2cf0e045f01faed88b..89f67b3c1b904cbcd9ed55e443d6fc67c8ca2769
2025-08-22 07:16:52 UTC to 2025-08-14 18:42:19 UTC
- Update `instruction_set` to use the attribute template (rust-lang/reference#1912)
- Update `debugger_visualizer` to use the attribute template (rust-lang/reference#1922)
- Update `collapse_debuginfo` to use the attribute template (rust-lang/reference#1923)
- Clarify operand evaluation order in compound assignment with primitiv… (rust-lang/reference#1941)
- Switch to using native mdbook fragment redirects (rust-lang/reference#1965)
- Fix traits implemented for function items (rust-lang/reference#1969)
- Clarify that safe extern items do not require unsafe (rust-lang/reference#1970)
- Update `type_length_limit` to use the attribute template (rust-lang/reference#1917)
- Add missing rule identifier for const outer generics (rust-lang/reference#1962)
- Fix indentation of static path restriction text (rust-lang/reference#1961)
- Add doc for `sse4a` and `tbm` (rust-lang/reference#1949)
## rust-lang/rust-by-example
2 commits in adc1f3b9012ad3255eea2054ca30596a953d053d..ad27f82c18464525c761a4a8db2e01785da59e1f
2025-08-20 23:50:16 UTC to 2025-08-13 21:41:46 UTC
- Support building books using mdbook in main (v0.5.x) (rust-lang/rust-by-example#1952)
- Improve the hints in `fmt` (1.2.3. Formatting); mention type casting (rust-lang/rust-by-example#1951)
Make `x test distcheck` self-contained
Before, the checked components were extracted under the checked out source root, which caused us to test some weird combination of tarball + checkout sources/aritfacts/configuration.
Now `x test distcheck` works with an external temporary directory instead, which should make it self-contained. I also moved some config from the Dockerfile to the test itself, and fixed an issue in tidy that caused `x test tidy` to fail on tarball sources.
I also removed `.args(&builder.config.configure_args)`, because it was passing all kinds of crap from the CI config to the distcheck step, which was making it less reproducible.
Fixes: https://github.com/rust-lang/rust/issues/145183
r? ```@jieyouxu```
try-job: x86_64-gnu-distcheck
compiletest: if a compiler fails, show its output
Before, when working on something like a `rustdoc-js` test, if you made a syntax error in a rust file, you would not get that error output unless you ran with `--verbose`, which would also cause an enormous amount of other output to be printed as well. This can also lead to frustration in new contributors who don't think to run with `--verbose`.
Now, if rustc or rustdoc is run by compiletest and produces an non-zero exit code, its output will be printed.
