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Author SHA1 Message Date
Pavel Grigorenko
507ebced16 Port #[fundamental] to the new attribute system 2025-07-09 01:26:27 +03:00
bors
34097a38af Auto merge of #140525 - lqd:stabilize-lld, r=petrochenkov
Use lld by default on `x86_64-unknown-linux-gnu` stable

This PR and stabilization report is joint work with `@Kobzol.`

#### Use LLD on `x86_64-unknown-linux-gnu` by default, and stabilize `-Clinker-features=-lld` and `-Clink-self-contained=-linker`

This PR proposes making LLD the default linker on the `x86_64-unknown-linux-gnu` target for the artifacts we distribute, and also stabilizing the `-Clinker-features=-lld` and `-Clink-self-contained=-linker` codegen options to make it possible to opt out.

LLD has been used as the default linker on nightly and CI on this target since May 2024 ([PR](https://github.com/rust-lang/rust/pull/124129), [blog post](https://blog.rust-lang.org/2024/05/17/enabling-rust-lld-on-linux.html)), and it seems like it is working fine, so we would like to propose stabilizing it.

The main motivation for using LLD instead of the default BFD linker is improving [compilation times](https://perf.rust-lang.org/compare.html?start=b3e117044c7f707293edc040edb93e7ec5f7040a&end=baed03c51a68376c1789cc373581eea0daf89967&stat=instructions%3Au&tab=compile). For example, in the linked benchmark, it makes incremental recompilation of `ripgrep` in `debug` more than twice faster. Another benefit is that Rust compilation becomes more consistent and self-contained, because we will use a known version of the LLD linker, rather than "whatever GNU ld version is on the user's system".

Due to the performance benefit being so huge, many people already opt into using LLD (or other fast linkers, such as mold) using various approaches ([1](https://github.com/search?type=code&q=%2Flinker-flavor%5B%3D+%5Dgnu-lld-cc%2F), [2](https://github.com/search?type=code&q=%2Flinker-features%5B%3D+%5D%5C%2Blld%2F), [3](https://github.com/search?type=code&q=language%3Atoml+%22-fuse-ld%3Dlld%22), [4](https://github.com/search?type=code&q=language%3Arust+%22-fuse-ld%3Dlld%22)). By making LLD the default linker on the `x86_64-unknown-linux-gnu` target, we will be able to speed up Rust compilation out of the box, without users having to opt in or know about it.

> You can find an extended version of this stabilization report which includes analysis of crater results and more data [here](https://hackmd.io/tFDifkUcSLGoHPBRIl0z8w?view).

## What is being stabilized
- `rust-lld` being used as the default linker on the `x86_64-unknown-linux-gnu` target.
    - Note that `rust-lld` is being enabled by default in the compiler artifacts distributed by our CI/rustup. It is still possible to use the system linker by default using `rust.lld = false` in `bootstrap.toml`, which can be useful e.g. for some Linux distros that might not want to use the LLD we distribute.
    - This is done by activating the LLD linker feature and using the self-contained linker on that target. Both of which are also usable on the CLI, if some opt outs are necessary, as described below.
- `-Clinker-features=-lld` on the `x86_64-unknown-linux-gnu` target. This codegen option tells rustc to disable using the LLD linker.
    - Note that other options for this codegen flag (`cc`) remain unstable.
    - Note that only the opt-out is being stabilized, and only for `x86_64-unknown-linux-gnu`: opting in, or using the flag on other targets would still need to pass `-Zunstable-options`.
    - This flag is being stabilized so that users can opt out of LLD on stable, which would it turn also opt out of using the self-contained linker (since it's an LLD).
- `-Clink-self-contained=-linker`. This codegen option tells rustc to use the self-contained linker. It's not particularly useful to turn it on by itself, but when enabled and combined with `-Clinker-features=+lld`, rustc will use the `rust-lld` linker wrapper shipped with the compiler toolchain, instead of some `lld` binary that the linker driver will find in the `PATH`.
    - Note that other options for this codegen flag (other than the previously stable `y/yes/n/no`).
    - Note that only the opt-out is being stabilized, and only for `x86_64-unknown-linux-gnu`: opting in, or using this flag on other targets would still need to pass `-Zunstable-options`.
    - This flag is being stabilized so that users can opt out of using self-contained linking on stable. Doing this would then fall back to using the system `lld`.

To opt out of using LLD, `RUSTFLAGS="-Clinker-features=-lld"` would be used. To opt out of using `rust-lld`, falling back to the LLD installed on the system, `RUSTFLAGS="-Clink-self-contained=-linker"` would be used.

## Tests

When enabling `rust-lld` on nightly, we also switched x64 linux to use it at stage >= 1, meaning that all tests have been running with lld since May 2024, on CI as well as contributors' machines. (Post opt-dist tests also had been using it when running their test subset earlier than that).

There are also a few tests dedicated to the CLI behavior, or ensuring the default linker is indeed the one we expect:

- [link-self-contained-consistency](1117bc1e6c/tests/ui/linking/link-self-contained-consistency.rs): Checks that `-Clink-self-contained` options are not inconsistent (i.e. that passing both `+linker` and `-linker` is an error).
- [link-self-contained-unstable](1117bc1e6c/tests/ui/linking/link-self-contained-unstable.rs): Checks that only the `-linker` and `y/yes/n/no` options for `-Clink-self-contained` are stable.
- [linker-features-unstable-cc](1117bc1e6c/tests/ui/linking/linker-features-unstable-cc.rs): Checks that only the non-lld options of `-Clinker-features` are unstable.
- [linker-features-lld-disallowed](1117bc1e6c/tests/ui/linking/linker-features-lld-disallowed.rs): Checks that `-Clinker-features=-lld` is only stable on `x86_64-unknown-linux-gnu`.
- [link-self-contained-linker-disallowed](1117bc1e6c/tests/ui/linking/link-self-contained-linker-disallowed.rs): Checks that `-Clink-self-contained=-linker` is only stable on `x86_64-unknown-linux-gnu`.
- [no-gc-encapsulation-symbols](1117bc1e6c/tests/ui/linking/no-gc-encapsulation-symbols.rs): Checks that that linker encapsulation symbols are not garbage collected by LLD, so that crates like [linkme](https://github.com/dtolnay/linkme) still work.
- [rust-lld](1117bc1e6c/tests/run-make/rust-lld): Checks that LLD is actually used when enabled with `-Clinker-features=+lld` and `-Clink-self-contained=+linker`.
- [rust-lld-x86_64-unknown-linux-gnu](1117bc1e6c/tests/run-make/rust-lld-x86_64-unknown-linux-gnu): Checks that LLD is used by default on `x86_64-unknown-linux-gnu` when the bootstrap `rust.lld` config option is `true`.
- [rust-lld-x86_64-unknown-linux-gnu-dist](1117bc1e6c/tests/run-make/rust-lld-x86_64-unknown-linux-gnu-dist): Dist test that checks that our distributed `x86_64-unknown-linux-gnu` archives actually use LLD by default.

## Ecosystem impact
As already stated, LLD has been used as the default linker on x64 Linux on nightly for almost a year, and we haven't seen any blockers to stabilization in that time. There were a handful of issues reported, these are discussed later below.

Furthermore, two crater runs ([November 2023](https://crater-reports.s3.amazonaws.com/pr-117684-2/index.html), [February 2025](https://crater-reports.s3.amazonaws.com/pr-137044-3/index.html)), were performed to test the impact of using LLD as the default linker. A triage of the earlier crater run was previously done [here](https://hackmd.io/OAJxlxc6Te6YUot9ftYSKQ), but all the important findings from both crater runs are reported below.

Below is a list of compatibility differences between BFD and LLD that we have encountered. There is a more thorough list of differences in [this post](https://maskray.me/blog/2020-12-19-lld-and-gnu-linker-incompatibilities) from the current LLD maintainer. From that post, "99.9% pieces of software work with ld.lld without a change".

---

### `.ctors/.dtors` sections
[#128286](https://github.com/rust-lang/rust/issues/128286) reported an issue where LLD was unable to link certain CUDA library was using these sections that were using the `.ctors/.dtors` ELF sections. These were deprecated a long time ago (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46770), replaced with a more modern `.init_array/.fini_array` sections. LLD doesn't (and won't) support these sections ([1](https://github.com/llvm/llvm-project/issues/68071), [2](https://github.com/llvm/llvm-project/issues/30572)), so if they appear in input object files, the linked artifact might produce incorrect behavior, because e.g. some global variables might not get initialized properly.

However, the usage of `.ctors/.dtors` should be very rare in practice. We have performed a [crater run](https://github.com/rust-lang/rust/pull/137044) to test this. It has identified only 8 crates where the `.ctors/.dtors` section is occurring in the final linked artifact. It was caused by a few crates using the `.ctors` link section manually, and by using a very (~6 year) old version of the [ctor](https://crates.io/crates/ctor) crate.

[Crater run analysis](https://hackmd.io/tFDifkUcSLGoHPBRIl0z8w?view#ctorsdtors-sections)

**Possible workaround**
It is possible to [detect](e5e2316712) if `.ctors/.dtors` section is present in the final linked artifact (LLD will keep it there, but it won't be populated), and warn users about it. This check is very cheap and doesn't even appear on [perf](https://github.com/rust-lang/rust/pull/112049#issuecomment-2661125340). We have benchmarked the check on a 240 MiB Chrome binary, where it took 0.8ms with page cache flushed, and 0.06ms with page cache primed (which should be the common case, as the linked artifact is written to disk just before the check is performed).

In theory, this could be also solved with a linker script that moves `.ctors` to `.init_array`.

We think that these sections should be so rare that it is not worth it to implement any workarounds for now.

---

### Different garbage collection behavior
[#130397](https://github.com/rust-lang/rust/issues/130397) reported an issue where LLD prunes a local symbol, so it is missing in the linked artifact. However, BFD keeps the same symbol, so it is a regression. This is caused by a difference in linker garbage collection.

Rust uses `--gc-sections` and puts each function into a separate linker section, which prunes unused code. There is some code (specifically the somewhat popular [linkme](https://github.com/dtolnay/linkme) crate) that (arguably ab-)uses so called linker encapsulation symbols to achieve distributed slices.

BFD (2.37+) uses a conservative linking mode that works as intended with this behavior, but it might slightly increase binary size of the linked artifact. LLD does not use this workaround by default, which causes the sections to be eliminated, but it can be made to use the conservative mode using [`-z nostart-stop-gc`](https://lld.llvm.org/ELF/start-stop-gc.html#z-start-stop-gc).

To avoid this issue, we told LLD to use the [conservative mode](https://github.com/rust-lang/rust/pull/137685), which maintains backwards compatibility with BFD. We found that it has [no effect](https://github.com/rust-lang/rust/pull/112049#issuecomment-2666028775) on compilation performance and binary size in our benchmark suite. With this change, `linkme` works. Since then, rust-lang/rust#140872 removed `linkme` distributed slice's dependence on conservative GC behavior, so this PR also removes that conservative mode: no transition period is necessary, as the PR immediately fixed the crate with no source changes.

[Crater run analysis](https://hackmd.io/tFDifkUcSLGoHPBRIl0z8w?view#Different-garbage-collection-behavior)

---

### Various uncommon issues

A small number of issues that only occurred in a handful of instances were found in crater, and it is unclear if LLD is at fault or if there is some other issue that was not detected with BFD.

You can examine these [here](https://hackmd.io/tFDifkUcSLGoHPBRIl0z8w?view#Various-uncommon-issues).

---

### Missing jobserver support
LLD doesn't support the jobserver protocol for limiting the number of threads used, it simply defaults to using all available cores, and is one of the reasons why it's faster than BFD. However, this should mostly be a non-issue, because most of the linking done during high parallelism sections of `cargo build` is linking of build scripts and proc macros, which are typically very fast to link (e.g. ~50ms), and a potential oversubscription of cores thus doesn't hurt that much.

When the final artifact is linked (which typically takes the most time), there should be no other sources of parallelism conflicts from compiling other code, so LLD should be able to use all available threads.

That being said, it is a difference of behavior, where previously a `-j` flag was generally not using more cpu than the specified limit. It can be impactful in some resource-constrained systems, but to be clear that is already the case today due to [cargo parallelism](https://github.com/rust-lang/cargo/issues/9157). This could be one reason to opt out of using `rust-lld` on some systems.

LLD has support for limiting the number of threads to use, so in theory rustc could try to get all the jobserver tokens available and use that as lld's thread limit. It'd still be suboptimal as new tokens would not be dynamically detected, and we could be using less threads than available.

We did a benchmark on a real-world crate that shows that using multiple LLD threads for intermediate artifacts doesn't seem to have a performance effect. You can find it [here](https://hackmd.io/tFDifkUcSLGoHPBRIl0z8w?view#Missing-jobserver-support).

---

#### Opting out of LLD in the ecosystem
We have also examined repositories where people opted out of LLD on nightly, using [this GitHub query](https://github.com/search?q=%22linker-features%3D-lld%22&type=code). The summary can be found below:

<details>
<summary>Summary of LLD opt outs</summary>

> This examination was performed on 2025-03-09.

Here we briefly examine the most common reasons why people use `-Zlinker-features=-lld`, based on comments and git history.

- Nix/NixOS ([1](59d703dff5/flake.nix (L33)), [2](3cc3449fc1/.cargo/config.toml (L4)), [3](32bdb17ced/.cargo/config.toml (L2)), [4](f5f657d014/Cargo.toml (L4)), [5](e4266f5c55/.cargo/config.toml (L10)), [6](22a4aef24e/README.md (L78)), [7](2222d53474/.cargo/config.toml (L2)), [8](b2ffa59d3e/.cargo/config.toml (L4)), [9](3ead4ef9c7/.cargo/config.toml (L2)), [10](ca6b8c8a5d/work/examples/lsp-client/src/extension.ts (L94)))
    - There was an [issue](https://github.com/NixOS/nixpkgs/issues/312661) with LLD, which seems to have been fixed with https://github.com/NixOS/nixpkgs/pull/314268.
 It's unclear whether that fixed all the Nix issues though.
- Issues with linkme ([1](ef388619ff/.cargo/config.toml (L4)), [2](be0fc5827f/README.md (L20)), [3](c5d8444d56/rust/.cargo/config.toml (L6)), [4](5b4cc1a519/.cargo/config.toml (L3)), [5](4e27c7de2a/.github/workflows/ci.yml (L82)), [6](8fe60c12bc/.github/workflows/code-coverage.yml (L48)), [7](c8b4683798/.github/workflows/ci.yml (L74)))
    - These should be resolved with the conservative garbage collection ([#137685](https://github.com/rust-lang/rust/pull/137685)).
- Bazel ([1](1823f69ed8/.bazelrc (L71))), WASM ([1](ca6b8c8a5d/work/examples/wasm-build.sh (L37)), [2](2bf99037ca/build.sh (L21))), uncategorized ([2](5118be6b9e/.cargo/config.toml (L3)), [3](45020c7e1d/.cargo/config.toml (L209)), [4](042eb835f7/README.md (L89)), [5](fd0b300676/exercises/.cargo/config.toml (L13)), [6](be65f2ec92/.github/workflows/rust.yml (L20)))
    - Reason unclear.
</details>

## History
The idea to use a faster linker by default has been on the radar for quite some time ([#39915](https://github.com/rust-lang/rust/issues/39915), [#71515](https://github.com/rust-lang/rust/issues/71515)). There were [very early attempts](https://github.com/rust-lang/rust/pull/29974) to use the gold linker by default, but these had to be [reverted](https://github.com/rust-lang/rust/pull/30913) because of compatibility issues. Support for LLD was implemented back in [2017](https://github.com/rust-lang/rust/pull/40018), but it has not been made default yet, except for some more niche targets, such as [WASM](https://github.com/rust-lang/rust/pull/48125), [ARM Cortex](https://github.com/rust-lang/rust/pull/53648) or [RISC-V](https://github.com/rust-lang/rust/pull/53822).

It took quite some time to figure out how should the interface for selecting the linker (and the way it is invoked) look like, as it differs a lot between different platforms, linkers and compiler drivers. During that time, LLD has matured and achieved [almost perfect compatibility](https://maskray.me/blog/2020-12-19-lld-and-gnu-linker-incompatibilities) with the default Linux linker (BFD).

- [#56351](https://github.com/rust-lang/rust/pull/56351) stabilized `-Clinker-flavor`, which is used to determine how to invoke the linker. It is especially useful on targets where selecting the linker directly with `-Clinker` is not possible or is impractical.
    - December 2018, author `@davidtwco,` reviewer `@nagisa`
- [#76158](https://github.com/rust-lang/rust/pull/76158) stabilized `-Clink-self-contained=[y|n]`, which allows overriding the compiler's heuristic for deciding whether it should use self-contained or external tools (linker, sanitizers, libc, etc.). It only allowed using the self-contained mode either for everything (`y`) or nothing (`n`), but did not allow granular choice.
    - September 2020, author `@mati864,` reviewer `@petrochenkov`
- [#85961](https://github.com/rust-lang/rust/pull/85961) implemented the `-Zgcc-ld` flag, which was a hacky way of opting into LLD usage.
    - June 2021, author `@sledgehammervampire,` reviewer `@petrochenkov`
- [MCP 510](https://github.com/rust-lang/compiler-team/issues/510) proposed stabilizing the behavior of `-Zgcc-ld` using more granular flags (`-Clink-self-contained=linker -Clinker-flavor=gcc-lld`).
    - Initially implemented in [#96827](https://github.com/rust-lang/rust/pull/96827), but `@petrochenkov` [suggested](https://github.com/rust-lang/rust/pull/96827#issuecomment-1208441595) a slightly different approach.
    - The PR was split into [#96884](https://github.com/rust-lang/rust/pull/96884), where it was decided what will be the individual components of `-Clink-self-contained=linker`.
    - And [#96401](https://github.com/rust-lang/rust/pull/96401), which implemented the `-Clinker-flavor` part.
    - The MCP was finally implemented in [#112910](https://github.com/rust-lang/rust/pull/112910).
    - [#116514](https://github.com/rust-lang/rust/pull/116514) then removed `-Zgcc-ld`, as it was replaced by `-Clinker-flavor=gnu-lld-cc` + `-Clink-self-contained=linker`.
    - April 2022 - October 2023, author `@lqd,` reviewer `@petrochenkov`

- Various linker handling refactorings were performed in the meantime: [#97375](https://github.com/rust-lang/rust/pull/97375), [#98212](https://github.com/rust-lang/rust/pull/98212), [#100126](https://github.com/rust-lang/rust/pull/100126), [#100552](https://github.com/rust-lang/rust/pull/100552), [#102836](https://github.com/rust-lang/rust/pull/102836), [#110807](https://github.com/rust-lang/rust/pull/110807), [#101988](https://github.com/rust-lang/rust/pull/101988), [#116515](https://github.com/rust-lang/rust/pull/116515)

- The implementation of linker flavors with LLD was causing a sort of a combinatorial explosion of various options.
[#119906](https://github.com/rust-lang/rust/pull/119906) suggested a different approach for linker flavors (described [here](https://github.com/rust-lang/rust/pull/119906#issuecomment-1894088306)), where the individual flavors could be enabled separately using `+/-` (e.g. `+lld`).
    - After some back and forth, this idea was moved to `-Clinker-features` (see [comment 1](https://github.com/rust-lang/rust/pull/119906#issuecomment-1895693162) and [comment 2](https://github.com/rust-lang/rust/pull/119906#issuecomment-1980801438)), which was implemented in [#123656](https://github.com/rust-lang/rust/pull/123656).
    - April 2024, author `@lqd,` reviewer `@petrochenkov`
- [#124129](https://github.com/rust-lang/rust/pull/124129) enabled LLD by default on nightly.
    - April 2024, author `@lqd,` reviewer `@petrochenkov`
- [#137685](https://github.com/rust-lang/rust/pull/137685), [#137926](https://github.com/rust-lang/rust/pull/137926) enabled the conservative gargage collection mode (`-znostart-stop-gc`) to improve compatibility with BFD.
    - February 2025, author `@lqd,` reviewer `@petrochenkov` (implementation), author `@kobzol,` reviewer `@lqd` (test)
- [#96025](https://github.com/rust-lang/rust/pull/96025) (April 2022), [#117684](https://github.com/rust-lang/rust/pull/117684) (November 2023), [#137044](https://github.com/rust-lang/rust/pull/137044) (February 2025): crater runs.

## Unresolved questions/concerns
- Is changing the linker considered a breaking change? In (hopefully very rare) cases, it might break some existing code. It should mostly only affect the final linked artifact, so it should be easy to opt out.
- Similarly, is the single-threaded behavior of such tools encompassed in our stability guarantee: it can be observed via the `-j` job limit (though I believe we have/had some open issues on sometimes using more CPU resources than the job count limit implied). As mentioned above, LLD does not support the jobserver protocol.
- A concern [was raised](https://github.com/rust-lang/rust/issues/71515#issuecomment-2612370229) about increased memory usage of LLD. We should probably let users know about the possibly increased memory usage, and jobserver incompatibility: we did so when announcing this landing on nightly.
- LLD seems to produce [slightly larger](https://perf.rust-lang.org/compare.html?start=b3e117044c7f707293edc040edb93e7ec5f7040a&end=baed03c51a68376c1789cc373581eea0daf89967&stat=size%3Alinked_artifact&tab=compile) binary artifacts. This can be partially clawed back using Identical Code Folding (`-Clink-args=-Wl,--icf=all`).
- Should we detect the outdated `.ctors/.dtors` sections to provide a better error message, even if that should be rare in practice?

---

### Next steps

After the FCP completes:
- we should land this PR at the beginning of a beta cycle, to maximize time for testing
- keep an eye on the beta crater run results for possible linker issues (or do a dedicated beta crater run with only this change)
- release a blog post announcing the change, and asking for testing feedback of the appropriate beta
- depending on feedback, or if a period of testing of 6 weeks is not long enough, we could keep this change on beta for another cycle

---

Development, testing, try builds were done in https://github.com/rust-lang/rust/pull/138645.

r? `@petrochenkov`
`@rustbot` label +needs-fcp +T-compiler
2025-07-08 22:24:06 +00:00
Pavel Grigorenko
12f6487d79 Port #[marker] to the new attribute system 2025-07-09 01:18:28 +03:00
Pavel Grigorenko
813ec60744 Port #[type_const] to the new attribute system 2025-07-09 01:06:29 +03:00
mejrs
25eb3829e5 Error on moving unsized values rather than ICE'ing 2025-07-08 22:37:12 +02:00
Matthias Krüger
cbf7f80d5c Rollup merge of #143555 - obi1kenobi:pg/target-feature-not-unsafe-rustdoc-json, r=aDotInTheVoid
Don't mark `#[target_feature]` safe fns as unsafe in rustdoc JSON.

Fixes https://github.com/rust-lang/rust/issues/142655 by explicitly checking whether functions are safe but using `#[target_feature]`, instead of relying on the `FnHeader::is_unsafe()` method which considers such functions unsafe.

I don't believe this merits a bump of the rustdoc JSON `FORMAT_VERSION` constant, since the format is unchanged and this is just a small bugfix.

r? aDotInTheVoid
2025-07-08 19:29:38 +02:00
Matthias Krüger
bc9b313cb5 Rollup merge of #143402 - GrigorenkoPV:attributes/link_attrs, r=jdonszelmann
Port several linking (linkage?) related attributes the new attribute system

This ports:
- `#[export_stable]`
- `#[ffi_const]`
- `#[ffi_pure]`
- `#[rustc_std_internal_symbol]`

Part of rust-lang/rust#131229

r? ``@oli-obk``
2025-07-08 19:29:37 +02:00
Oli Scherer
b1d45f6b3e Remove const_eval_select hack 2025-07-08 15:49:00 +00:00
Oli Scherer
543c860ea6 Constify Fn* traits 2025-07-08 14:36:43 +00:00
bors
f838cbc06d Auto merge of #134628 - estebank:const-default, r=oli-obk
Make `Default` const and add some `const Default` impls

Full list of `impl const Default` types:

- ()
- bool
- char
- std::ascii::Char
- usize
- u8
- u16
- u32
- u64
- u128
- i8
- i16
- i32
- i64
- i128
- f16
- f32
- f64
- f128
- std::marker::PhantomData<T>
- Option<T>
- std::iter::Empty<T>
- std::ptr::Alignment
- &[T]
- &mut [T]
- &str
- &mut str
- String
- Vec<T>
2025-07-08 14:04:40 +00:00
Rémy Rakic
e32b1d7126 expand -Clink-self-contained tests
- update existing tests for stabilization
- ensure `-Clink-self-contained=-linker` is only stable on x64 linux
- test invalid `-Clink-self-contained` components
2025-07-08 10:24:10 +00:00
Rémy Rakic
856c662567 expand -Clinker-features tests
- ensure only `-Clinker-features=-lld` is stabilized, and only on x64
  linux
- test `-Clinker-features` unstable values
2025-07-08 09:30:44 +00:00
Rémy Rakic
3f194a86ee stabilize -Clink-self-contained=-linker on x64 linux
This stabilizes a subset of the `-Clink-self-contained` components on x64 linux:
the rust-lld opt-out.

The opt-in is not stabilized, as interactions with other stable flags require
more internal work, but are not needed for stabilizing using rust-lld by default.

Similarly, since we only switch to rust-lld on x64 linux, the opt-out is
only stabilized there. Other targets still require `-Zunstable-options`
to use it.
2025-07-08 09:21:35 +00:00
Rémy Rakic
2e6d82c9c9 stabilize -Clinker-features=-lld on x64 linux
This stabilizes a subset of the `-Clinker-features` components on x64 linux:
the lld opt-out.

The opt-in is not stabilized, as interactions with other stable flags require
more internal work, but are not needed for stabilizing using rust-lld by default.

Similarly, since we only switch to rust-lld on x64 linux, the opt-out is
only stabilized there. Other targets still require `-Zunstable-options`
to use it.
2025-07-08 09:04:21 +00:00
Jieyou Xu
37136dd974 Disable tests/run-make/mte-ffi
See RUST-141600: this test is broken in two ways:

1. This test triggers `-Wincompatible-pointer-types` on GCC 14.
2. This test requires ARMv8.5+ w/ MTE extensions enabled, but GHA CI
   runner hardware do not have this enabled.
2025-07-08 16:40:10 +08:00
Jieyou Xu
24a25dbb88 Revert tests/run-make/mte-ffi changes
Partially reverts commit 40311c4dcf.
2025-07-08 16:40:05 +08:00
Rémy Rakic
aa52711543 add post-dist test for checking that we use LLD
And remove the previous beta/stable/nightly LLD tests.
2025-07-08 08:08:40 +00:00
Scott McMurray
8cf2c71243 Let rvalue_creates_operand return true for *all* Rvalue::Aggregates
Inspired by <https://github.com/rust-lang/rust/pull/138759#discussion_r2156375342> where I noticed that we were nearly at this point, plus the comments I was writing in 143410 that reminded me a type-dependent `true` is fine.

This PR splits the `OperandRef::builder` logic out to a separate type, with the updates needed to handle SIMD as well.  In doing so, that makes the existing `Aggregate` path in `codegen_rvalue_operand` capable of handing SIMD values just fine.

As a result, we no longer need to do layout calculations for aggregate result types when running the analysis to determine which things can be SSA in codegen.
2025-07-07 23:08:10 -07:00
bors
2783fc43fd Auto merge of #143621 - matthiaskrgr:rollup-p1ce8l7, r=matthiaskrgr
Rollup of 7 pull requests

Successful merges:

 - rust-lang/rust#142098 (Implement `int_format_into` feature)
 - rust-lang/rust#143567 (Point to correct argument in Func Call when Self type fails trait bound)
 - rust-lang/rust#143570 (consider nested cases for duplicate RPITIT)
 - rust-lang/rust#143571 (remove `has_nested` from builtin candidates)
 - rust-lang/rust#143586 (Fix wrong cache event query key)
 - rust-lang/rust#143589 (const-block-as-pattern: do not refer to no-longer-existing nightly feature)
 - rust-lang/rust#143608 (Fix in std::String docs)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-07-08 03:30:58 +00:00
Predrag Gruevski
717041232a Don't mark #[target_feature] safe fns as unsafe in rustdoc JSON. 2025-07-08 02:02:56 +00:00
Matthias Krüger
65dded8387 Rollup merge of #143589 - RalfJung:const-pat, r=compiler-errors
const-block-as-pattern: do not refer to no-longer-existing nightly feature

Surely everyone who used this nightly feature has fixed their code by now. So let's not confused people on stable that try to use a const block as a pattern by referring to some dead nightly feature.
2025-07-08 03:09:58 +02:00
Matthias Krüger
a4e05e1f74 Rollup merge of #143570 - bvanjoi:issue-143560, r=compiler-errors
consider nested cases for duplicate RPITIT

Fixes rust-lang/rust#143560

r? `@compiler-errors`

cc `@Zoxc`
2025-07-08 03:09:57 +02:00
Matthias Krüger
40e1ccf458 Rollup merge of #143567 - xizheyin:143336, r=compiler-errors
Point to correct argument in Func Call when Self type fails trait bound

Fixes rust-lang/rust#143336

When a trait bound fails due to the `Self` type parameter, `adjust_fulfillment_errors` now correctly points to the corresponding function argument instead of incorrectly pointing to other arguments. This is because `Call` may also need to handle the `self` parameter, and not just `MethodCall` needs to be handled, as rust-lang/rust#143336.

r? compiler
2025-07-08 03:09:56 +02:00
bors
688ea65df6 Auto merge of #143433 - oli-obk:ty_span_qry, r=compiler-errors
Add `ty_span` query

r? `@compiler-errors`

fixes diagnostic regressions from https://github.com/rust-lang/rust/pull/142030

Also uses the new query in `check_const_item`
2025-07-08 00:11:13 +00:00
Esteban Küber
c3301503b9 Make Default const and add some const Default impls
Full list of `impl const Default` types:

- ()
- bool
- char
- Cell
- std::ascii::Char
- usize
- u8
- u16
- u32
- u64
- u128
- i8
- i16
- i32
- i64
- i128
- f16
- f32
- f64
- f128
- std::marker::PhantomData<T>
- Option<T>
- std::iter::Empty<T>
- std::ptr::Alignment
- &[T]
- &mut [T]
- &str
- &mut str
- String
- Vec<T>
2025-07-07 22:09:37 +00:00
Alona Enraght-Moony
45053e21b2 Run tests/rustdoc-json/attrs/target_features on all hosts.
Makes it more convenient to test rustdoc on non x86_64. I mainly care
about the aarch64 dev-desktops.

This works because rustdoc uses all target features, not just that of
the target.
2025-07-07 21:56:54 +00:00
Matthias Krüger
f5df1f562c Rollup merge of #143583 - folkertdev:loop-match-no-terminator-on-block, r=bjorn3
`loop_match`: fix 'no terminator on block'

tracking issue: https://github.com/rust-lang/rust/issues/132306
fixes https://github.com/rust-lang/rust/issues/143435

The argument `block` was not properly closed on an error path.

r? `@bjorn3`
2025-07-07 19:55:35 +02:00
Matthias Krüger
6c8482ee2c Rollup merge of #143539 - JonathanBrouwer:ice-regression-tests, r=oli-obk
Regression tests for repr ICEs

Closes https://github.com/rust-lang/rust/issues/143522
Closes https://github.com/rust-lang/rust/issues/143479

Both issues were already (accidentally) fixed in this PR, but having the tests is nice https://github.com/rust-lang/rust/pull/143252

r? `@jdonszelmann`
2025-07-07 19:55:33 +02:00
Matthias Krüger
2554c424ef Rollup merge of #143340 - nabijaczleweli:awhile, r=mati865
awhile -> a while where appropriate
2025-07-07 19:55:32 +02:00
Matthias Krüger
00a4418158 Rollup merge of #132469 - estebank:issue-132041, r=Nadrieril
Do not suggest borrow that is already there in fully-qualified call

When encountering `&str::from("value")` do not suggest `&&str::from("value")`.

Fix #132041.
2025-07-07 19:55:31 +02:00
Bastian Kersting
b4e68e212e Respect endianness correctly in CheckEnums test suite
The endianness can change the test expectation for the enum check.
This change is fixing the failing tests on big endian by changing
the tests so that they behave the same as on little endian.
2025-07-07 17:58:44 +02:00
Ralf Jung
1a6eff747f const-block-as-pattern: do not refer to no-longer-existing nightly feature 2025-07-07 16:18:41 +02:00
Pavel Grigorenko
5d7771e50d Port #[ffi_pure] to the new attribute system 2025-07-07 14:59:01 +03:00
Folkert de Vries
6d58a88c3c loop_match: fix 'no terminator on block' 2025-07-07 13:55:40 +02:00
Pavel Grigorenko
99a9fe1b22 Port #[ffi_const] to the new attribute system 2025-07-07 14:52:52 +03:00
许杰友 Jieyou Xu (Joe)
b6015a68de Rollup merge of #143551 - compiler-errors:root-sub, r=cjgillot
Dont resolve instance of root in `mir_callgraph_cyclic`

`Instance::try_resolve` on a default trait body method will always fail, since it's still possible to further substitute. This leads to a cycle, since in `tests/mir-opt/inline_default_trait_body.rs`, both `Trait::a` and `Trait::b` need to consider the other to be cyclical, but since we couldn't resolve a body, we'd just consider *nothing* to be cyclical.

The root instance we care about when computing `mir_callgraph_cyclic` is trivial to compute (it's just `InstanceKind::Item`), so just replace it with a call to `Instance::new_raw`.

r? `@cjgillot` `@oli-obk`

Fixes rust-lang/rust#143534
2025-07-07 19:45:41 +08:00
许杰友 Jieyou Xu (Joe)
02aa4ff12f Rollup merge of #143524 - makai410:smir-move-back, r=oli-obk
Move `stable_mir` back to its own crate

We've finished the refactoring, so it's time to move `stable_mir` back to its own crate.

This PR leaves an empty `rustc_internal` module with a `#[deprecated]` attribute in `rustc_smir` to let users know we just moved it to `stable_mir`.
2025-07-07 19:45:40 +08:00
许杰友 Jieyou Xu (Joe)
4ba4b5f24f Rollup merge of #143482 - ia0:fix, r=fee1-dead
Fix short linker error output

This PR does 2 things:

- It removes the braces when there's a single element. This is required since brace expansion (at least in bash and zsh) only triggers if there's at least 2 elements.

- It removes the extra `.rlib` suffixes of the elements. See https://github.com/rust-lang/rust/pull/135707#discussion_r2185212393 for context.

Running `cargo +stage1 build` on the following program:

```rust
unsafe extern "C" {
    fn foo() -> libc::c_int;
}

fn main() {
    let x = unsafe { foo() } as u32;
    // println!("{}", data_encoding::BASE64.encode(&x.to_le_bytes()));
}
```

Gives the following diff before and after the PR:

```diff
-/tmp/foo/target/debug/deps/{liblibc-faf416f178830595.rlib}.rlib
+/tmp/foo/target/debug/deps/liblibc-faf416f178830595.rlib
```

Running on the same program with the additional dependency, we get the following diff:

```diff
-/tmp/foo/target/debug/deps/{liblibc-faf416f178830595.rlib,libdata_encoding-84bb5aadfa9e8839.rlib}.rlib
+/tmp/foo/target/debug/deps/{liblibc-faf416f178830595,libdata_encoding-84bb5aadfa9e8839}.rlib
```
2025-07-07 19:45:40 +08:00
许杰友 Jieyou Xu (Joe)
fc13c96ca6 Rollup merge of #143464 - workingjubilee:make-debug-rs-cross-compile, r=oli-obk
Make tests/ui/abi/debug.rs cross-compile

Resumption of rust-lang/rust#141979, making the test cross-compile.
2025-07-07 19:45:39 +08:00
Pavel Grigorenko
bb8b741c32 Port #[export_stable] to the new attribute system 2025-07-07 14:33:20 +03:00
bohan
e1720d7396 consider nested cases for duplicate RPITIT 2025-07-07 17:09:39 +08:00
xizheyin
796b4d1fb4 Point to correct argument in Func Call when Self type fails trait bound
When a trait bound fails due to the Self type parameter, adjust_fulfillment_errors
now correctly points to the corresponding function argument instead of incorrectly
pointing to other arguments.

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-07-07 16:47:15 +08:00
xizheyin
cf7e896cf8 Add test tests/ui/trait-bounds/false-span-in-trait-bound-label.rs
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-07-07 16:30:14 +08:00
Oli Scherer
62929b9420 Add ty_span query 2025-07-07 08:13:12 +00:00
xizheyin
229be21d0d Add ui test unnessary-error-issue-138401.rs
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-07-07 15:27:01 +08:00
Makai
627cefa993 remove rustc_smir from tests 2025-07-07 03:45:09 +00:00
Jacob Pratt
11b24c108d Rollup merge of #143344 - JonathanBrouwer:path-parser, r=jdonszelmann
Port `#[path]` to the new attribute parsing infrastructure

Ports `#[path]` to the new attribute parsing infrastructure for https://github.com/rust-lang/rust/issues/131229#issuecomment-2971353197

This PR duplicates a change from https://github.com/rust-lang/rust/pull/143237
Draft until that one is merged
2025-07-07 03:26:06 +02:00
Jacob Pratt
d748e70fea Rollup merge of #143206 - Jules-Bertholet:align-attr-fixes, r=workingjubilee
Align attr fixes

- Remove references to the superseded `repr(align)` syntax
- Allow the attribute on fn items in `extern` blocks
- Test attribute in combination with `async fn` and `dyn`

r? workingjubilee

Tracking issue: https://github.com/rust-lang/rust/issues/82232
`@rustbot` label A-attributes F-fn_align T-compiler
2025-07-07 03:26:05 +02:00
Michael Goulet
a40274d6cc Dont resolve instance of root in mir_callgraph_cyclic 2025-07-06 23:01:45 +00:00
Jules Bertholet
8f86c4abec Skip align tests on wasm 2025-07-06 18:10:52 -04:00