update and clarify StructuralPartialEq docs
This apparently hasn't been updated when we finalized the current const pattern matching behavior.
Fixes https://github.com/rust-lang/rust/issues/92454 by providing rationale and context in the docs linked from that error message.
this also makes the rust.docs-minification option work
as advertised in config.toml
nothing fancy this time, this is intended to be perma-unstable.
it's only really here for the benefit of rustdoc devs.
mitegates https://github.com/rust-lang/rust/issues/135345
Eagerly collect mono items for non-generic closures
This allows users to use `-Zprint-mono-items=eager` to eagerly monomorphize closures and coroutine bodies, in case they want to inspect the LLVM or ASM for those items.
`-Zprint-mono-items`, which used to be called `-Zprint-trans-items`, was originally added in https://github.com/rust-lang/rust/pull/30900:
> Eager mode is meant to be used in conjunction with incremental compilation
> where a stable set of translation items is more important than a minimal
> one. Thus, eager mode will instantiate drop-glue for every drop-able type
> in the crate, even of no drop call for that type exists (yet). It will
> also instantiate default implementations of trait methods, something that
> otherwise is only done on demand.
Although it remains an unstable option, its purpose has somewhat expanded since then, and as far as I can tell it's generally useful for cases when you want to monomorphize as many items as possible, even if they're unreachable. Specifically, it's useful for debugging since you can look at the codegen'd body of a function, since we don't emit items that are not reachable in monomorphization.
And even more specifically, it would be very to monomorphize the coroutine body of an async fn, since those you can't easily call those without a runtime. This PR enables this usecase since we now monomorphize `DefKind::Closure`.
Rename `BitSet` to `DenseBitSet`
r? `@Mark-Simulacrum` as you requested this in https://github.com/rust-lang/rust/pull/134438#discussion_r1890659739 after such a confusion.
This PR renames `BitSet` to `DenseBitSet` to make it less obvious as the go-to solution for bitmap needs, as well as make its representation (and positives/negatives) clearer. It also expands the comments there to hopefully make it clearer when it's not a good fit, with some alternative bitsets types.
(This migrates the subtrees cg_gcc and clippy to use the new name in separate commits, for easier review by their respective owners, but they can obvs be squashed)
Avoid ICE: Account for `for<'a>` types when checking for non-structural type in constant as pattern
When we encounter a constant in a pattern, we check if it is non-structural. If so, we check if the type implements `PartialEq`, but for types with escaping bound vars the check would be incorrect as is, so we break early. This is ok because these types would be filtered anyways.
Slight tweak to output to remove unnecessary context as a drive-by.
Fix#134764.
add `-Zmin-function-alignment`
tracking issue: https://github.com/rust-lang/rust/issues/82232
This PR adds the `-Zmin-function-alignment=<align>` flag, that specifies a minimum alignment for all* functions.
### Motivation
This feature is requested by RfL [here](https://github.com/rust-lang/rust/issues/128830):
> i.e. the equivalents of `-fmin-function-alignment` ([GCC](https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fmin-function-alignment_003dn), Clang does not support it) / `-falign-functions` ([GCC](https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-falign-functions), [Clang](https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang1-falign-functions)).
>
> For the Linux kernel, the behavior wanted is that of GCC's `-fmin-function-alignment` and Clang's `-falign-functions`, i.e. align all functions, including cold functions.
>
> There is [`feature(fn_align)`](https://github.com/rust-lang/rust/issues/82232), but we need to do it globally.
### Behavior
The `fn_align` feature does not have an RFC. It was decided at the time that it would not be necessary, but maybe we feel differently about that now? In any case, here are the semantics of this flag:
- `-Zmin-function-alignment=<align>` specifies the minimum alignment of all* functions
- the `#[repr(align(<align>))]` attribute can be used to override the function alignment on a per-function basis: when `-Zmin-function-alignment` is specified, the attribute's value is only used when it is higher than the value passed to `-Zmin-function-alignment`.
- the target may decide to use a higher value (e.g. on x86_64 the minimum that LLVM generates is 16)
- The highest supported alignment in rust is `2^29`: I checked a bunch of targets, and they all emit the `.p2align 29` directive for targets that align functions at all (some GPU stuff does not have function alignment).
*: Only with `build-std` would the minimum alignment also be applied to `std` functions.
---
cc `@ojeda`
r? `@workingjubilee` you were active on the tracking issue
bump `rustc-perf` submodule
This updates the `rustc-perf` submodule to pull in the recent changes, in particular the error handling in https://github.com/rust-lang/rustc-perf/pull/2021 fixing the error we saw in a recent run.
I think I did this correctly, submodules are so annoying.
r? kobzol
(opening as draft to do a perf run and check that nothing has changed indeed)
