Add profiling of bootstrap commands using Chrome events
Since we now have support for tracing in bootstrap, and the execution of most commands is centralized within a few functions, it's quite trivial to also trace command execution, and visualize it using the Chrome profiler. This can be helpful both to profile what takes time in bootstrap and also to get a visual idea of what happens in a given bootstrap invocation (since the execution of external commands is usually the most interesting thing).
This is how it looks:

I first tried to use [tracing-flame](https://github.com/tokio-rs/tracing/tree/master/tracing-flame), but the output wasn't very useful, because the event/stackframe names were bootstrap code locations, instead of the command contents.
r? ``@jieyouxu``
[AIX] expect `EINVAL` for `pthread_mutex_destroy`
Calling `pthread_mutex_destory` on a mutex initalized with the static initializer macro `PTHREAD_MUTEX_INITIALIZER` will result in `EINVAL` if the mutex is not lock/unlocked prior to calling `pthread_mutex_destroy`.
Simplify `rustc_span` `analyze_source_file`
Simplifies the logic to what the code *actually* does, which is to just record newlines and multibyte characters. Checking for other ASCII control characters is unnecessary because the generic fallback doesn't do anything for those cases.
Also uses a simpler (and more efficient) means of iterating the set bits of the mask.
valtree performance tuning
Summary: This PR makes type checking of code with many type-level constants faster.
After https://github.com/rust-lang/rust/pull/136180 was merged, we observed a small perf regression (https://github.com/rust-lang/rust/pull/136318#issuecomment-2635562821). This happened because that PR introduced additional copies in the fast reject code path for consts, which is very hot for certain crates: 6c1d960d88/compiler/rustc_type_ir/src/fast_reject.rs (L486-L487)
This PR improves the performance again by properly interning the valtrees so that copying and comparing them becomes faster. This will become especially useful with `feature(adt_const_params)`, so the fast reject code doesn't have to do a deep compare of the valtrees.
Note that we can't just compare the interned consts themselves in the fast reject, because sometimes `'static` lifetimes in the type are be replaced with inference variables (due to canonicalization) on one side but not the other.
A less invasive alternative that I considered is simply avoiding copies introduced by https://github.com/rust-lang/rust/pull/136180 and comparing the valtrees it in-place (see commit: 9e91e50ac5 / perf results: https://github.com/rust-lang/rust/pull/136593#issuecomment-2642303245), however that was still measurably slower than interning.
There are some minor regressions in secondary benchmarks: These happen due to changes in memory allocations and seem acceptable to me. The crates that make heavy use of valtrees show no significant changes in memory usage.
Rollup of 8 pull requests
Successful merges:
- #134999 (Add cygwin target.)
- #136559 (Resolve named regions when reporting type test failures in NLL)
- #136660 (Use a trait to enforce field validity for union fields + `unsafe` fields + `unsafe<>` binder types)
- #136858 (Parallel-compiler-related cleanup)
- #136881 (cg_llvm: Reduce visibility of all functions in the llvm module)
- #136888 (Always perform discr read for never pattern in EUV)
- #136948 (Split out the `extern_system_varargs` feature)
- #136949 (Fix import in bench for wasm)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix import in bench for wasm
This import was causing annoying unused import errors when checking the standard library for some wasm targets. The problem is that everything here is disabled if it is wasm32, but this import wasn't cfg'd.
Split out the `extern_system_varargs` feature
After the stabilization PR was opened, `extern "system"` functions were added to `extended_varargs_abi_support`. This has a number of questions regarding it that were not discussed and were somewhat surprising. It deserves to be considered as its own feature, separate from `extended_varargs_abi_support`.
Tracking issue:
- https://github.com/rust-lang/rust/issues/136946
Always perform discr read for never pattern in EUV
Always perform a read of `!` discriminants to ensure that it's captured by closures in expr use visitor
Fixes#136852
r? Nadrieril or reassign
cg_llvm: Reduce visibility of all functions in the llvm module
Next part of #135502
This reduces the visibility of all functions in the `llvm` module to `pub(crate)` and marks the `enzyme_ffi` modules with `#![expect(dead_code)]` (as previously discussed: <https://github.com/rust-lang/rust/pull/135502#discussion_r1915608085>).
r? ``@Zalathar``
Parallel-compiler-related cleanup
Parallel-compiler-related cleanup
I carefully split changes into commits. Commit messages are self-explanatory. Squashing is not recommended.
cc "Parallel Rustc Front-end" https://github.com/rust-lang/rust/issues/113349
r? SparrowLii
``@rustbot`` label: +WG-compiler-parallel
Rename rustc_middle::Ty::is_unsafe_ptr to is_raw_ptr
The wording unsafe pointer is less common and not mentioned in a lot of places, instead this is usually called a "raw pointer". For the sake of uniformity, we rename this method.
This came up during the review of
https://github.com/rust-lang/rust/pull/134424.
r? `@Noratrieb`
Rollup of 10 pull requests
Successful merges:
- #136758 (tests: `-Copt-level=3` instead of `-O` in assembly tests)
- #136761 (tests: `-Copt-level=3` instead of `-O` in codegen tests)
- #136784 (Nuke `Buffer` abstraction from `librustdoc`, take 2 💣)
- #136838 (Check whole `Unsize` predicate for escaping bound vars)
- #136848 (add docs and ut for bootstrap util cache)
- #136871 (dev-guide: Link to `t-lang` procedures for new features)
- #136890 (Change swap_nonoverlapping from lang to library UB)
- #136901 (compiler: give `ExternAbi` truly stable `Hash` and `Ord`)
- #136907 (compiler: Make middle errors `pub(crate)` and bury the dead code)
- #136916 (use cc archiver as default in `cc2ar`)
r? `@ghost`
`@rustbot` modify labels: rollup
use cc archiver as default in `cc2ar`
We should remove entire `cc2ar` but `cc` doesn't seem to cover all the conditions that `cc2ar` handles. For now, I replaced the `else` logic only, which is a bit hacky and unstable.
Fixes#136759
compiler: give `ExternAbi` truly stable `Hash` and `Ord`
Currently, `ExternAbi` has a bunch of code to handle the reality that, as an enum, adding more variants to it will risk it hashing differently. It forces all of those variants to be added in a fixed order, except this means that the order of the variants doesn't correspond to any logical order except "historical accident". This is all to avoid having to rebless two tests. Perhaps there were more, once upon a time? But then we invented normalization in our test suite to handle exactly this sort of issue in a more general way.
There are two options here:
- Get rid of all the logical overhead and shrug, embracing blessing a couple of tests sometimes
- Change `ExternAbi` to have an ordering and hash that doesn't depend on the number of variants
As `ExternAbi` is essentially a strongly-typed string, and thus no two strings can be identical, this implements the second of the two by hand-implementing `Ord` and `Hash` to make the hashing and comparison based on the string! This will diff the current hashes, but they will diff no more after this.
Change swap_nonoverlapping from lang to library UB
The implementation of ptr::swap_nonoverlapping does not always escalate its safety contract to language UB, so it should be `check_library_ub`.
Fixes https://github.com/rust-lang/miri/issues/4188
dev-guide: Link to `t-lang` procedures for new features
I was confused in https://github.com/rust-lang/rust/pull/136867, because while I did remember that such a procedure existed, but I couldn't seem to find it in the dev guide.
Nuke `Buffer` abstraction from `librustdoc`, take 2 💣
In https://github.com/rust-lang/rust/pull/136656 I found out that the for_html field in the Buffer struct was never read, and pondered if Buffer had any utility at all. `@GuillaumeGomez` said he agrees that it can be just removed. So this PR is me removing it. So, r? `@aDotInTheVoid` , maybe?
Supersedes #136748
tests: `-Copt-level=3` instead of `-O` in codegen tests
An effective blocker for redefining the meaning of `-O` is to stop reusing this somewhat ambiguous alias in our own codegen test suite. The choice between `-Copt-level=2` and `-Copt-level=3` is arbitrary for most of our tests. In most cases it makes no difference, so I set most of them to `-Copt-level=3`, as it will lead to slightly more "normalized" codegen.
try-job: test-various
try-job: arm-android
try-job: armhf-gnu
try-job: i686-gnu-1
try-job: i686-gnu-2
try-job: i686-mingw
try-job: i686-msvc-1
try-job: i686-msvc-2
try-job: aarch64-apple
try-job: aarch64-gnu
tests: `-Copt-level=3` instead of `-O` in assembly tests
An effective blocker for redefining the meaning of `-O` is to stop reusing this somewhat ambiguous alias in our own assembly test suite. The choice between `-Copt-level=2` and `-Copt-level=3` is arbitrary for most of our tests. In most cases it makes no difference, so I set most of them to `-Copt-level=3`, as it will lead to slightly more "normalized" assembly.
Rollup of 8 pull requests
Successful merges:
- #134981 ( Explain that in paths generics can't be set on both the enum and the variant)
- #136698 (Replace i686-unknown-redox target with i586-unknown-redox)
- #136767 (improve host/cross target checking)
- #136829 ([rustdoc] Move line numbers into the `<code>` directly)
- #136875 (Rustc dev guide subtree update)
- #136900 (compiler: replace `ExternAbi::name` calls with formatters)
- #136913 (Put kobzol back on review rotation)
- #136915 (documentation fix: `f16` and `f128` are not double-precision)
r? `@ghost`
`@rustbot` modify labels: rollup
compiler: replace `ExternAbi::name` calls with formatters
Most of these just format the ABI string, so... just format ExternAbi? This makes it more consistent and less jank when we can do it.
chore: update rustc-hash 2.1.0 to 2.1.1
This PR updates the rustc-hash crate to include a palliative fix for #135477.
The discussion for this can be found in the issue and on https://github.com/rust-lang/rustc-hash/pull/55.
This PR is the output of running `cargo +nightly update rustc-hash@2.1.0`. I ran all tests locally and they all seem to pass, with the exception of `tests/ui/process/nofile-limit.rs` which always fails on my setup.
`@steffahn` `@orlp` and `@Noratrieb` all have full context on this, I'm opening the pull request trying to be helpful. I'm not sure if anything else needs to be done, like documentation I'm not aware of or running any special CIs but if I can do anything else please let me know!