Specifically:
- `HashStable` -> `StableHash` (trait)
- `HashStable` -> `StableHash` (derive)
- `HashStable_NoContext` -> `StableHash_NoContext` (derive)
Note: there are some names in `compiler/rustc_macros/src/hash_stable.rs`
that are still to be renamed, e.g. `HashStableMode`.
Part of MCP 983.
Simplify `HashStable`
This PR:
- Simplifies the `HashStable` trait, by moving its generic parameter from the trait to its single method.
- Eliminates the need for the non-obvious `derive(HashStable)`/`derive(HashStable_Generic)` distinction.
- Reduces the need for, and clarifies, the non-obvious `derive(HashStable)`/`derive(HashStable_NoContext)` distinction.
r? @fee1-dead
Update with new LLVM 22 target for `wasm32-wali-linux-musl` target
This is a reopening of rust-lang/rust#155654, which was closed abruptly due to changed commit SHAs on my end during merge.
NVPTX: Drop support for old architectures and old ISAs
This is the implementation of [this MCP](https://github.com/rust-lang/compiler-team/issues/965#issuecomment-3837320262)
I believe it was said that no FCP was needed, but if that is incorrect then the FCP is anyway scheduled to finish in 2 days so it can in any case be merged then.
[AIX] update linker default to bcdtors
The bcdtor mode affects how the AIX linker choose to pull in static constructors and destructors (https://www.ibm.com/docs/en/aix/7.2.0?topic=l-ld-command) to the link.
The current setting of all makes static init in archive members live regardless of if the archive member would be otherwise referenced, causing that whole archive member to become part of the link.
This default was initially retained for compatibility purposes with historical compilers on the platform which defaulted to this setting. Unfortunately this greedy pulling in of static init can have unintended consequences for applications, for example for programs linked against parts of compiler-rt which contain optional instrumentation (containing static initializers) which may be unused as these now become live in all programs regardless of use.
For that reason and similar reasons, this PR switches the default to mbr, which only extracts static init from archive members which would otherwise be referenced. This gives a behaviour very consistent with linkers on other platforms (e.g. Linux).
Users requiring the old default behaviour can manually pass `-bcdtors:all` on the link step which will override any default we pass here.
(Note: this mirrors LLVM change: https://github.com/llvm/llvm-project/pull/191265)
Fix tier level for 5 thumb bare-metal ARM targets
The spec files for 5 Thumb-mode bare-metal ARM targets incorrectly set tier: Some(2), while the documentation correctly lists them as Tier 3. This mismatch was introduced in PR #150556 — the intent was Tier 2 eventually, but these targets should sit at Tier 3 until a proper Tier 3 → Tier 2 promotion MCP is submitted and approved.
This PR changes tier: Some(2) → Some(3) in the following spec files, making them consistent with the docs:
thumbv7a-none-eabi
thumbv7a-none-eabihf
thumbv7r-none-eabi
thumbv7r-none-eabihf
thumbv8r-none-eabihf
PS: No doc changes needed — they already correctly state Tier 3.
r?
Enable AddressSanitizer on arm-unknown-linux-gnueabihf and armv7-unknown-linux-gnueabihf
Add SanitizerSet::ADDRESS to the supported_sanitizers for the arm-unknown-linux-gnueabihf and armv7-unknown-linux-gnueabihf targets.
The AddressSanitizer is already enabled on the armv7-linux-androideabi platform, which shares the same ARM architecture. There is no reason these Linux GNU targets should not also support it, as the underlying LLVM support for ASan on 32-bit ARM is already in place.
Add SanitizerSet::ADDRESS to the supported_sanitizers for the
arm-unknown-linux-gnueabihf and armv7-unknown-linux-gnueabihf targets.
The AddressSanitizer is already enabled on the armv7-linux-androideabi
platform, which shares the same ARM architecture. There is no reason
these Linux GNU targets should not also support it, as the underlying
LLVM support for ASan on 32-bit ARM is already in place.
preserve SIMD element type information
Preserve the SIMD element type and provide it to LLVM for better optimization.
This is relevant for AArch64 types like `int16x4x2_t`, see also https://github.com/llvm/llvm-project/issues/181514. Such types are defined like so:
```rust
#[repr(simd)]
struct int16x4_t([i16; 4]);
#[repr(C)]
struct int16x4x2_t(pub int16x4_t, pub int16x4_t);
```
Previously this would be translated to the opaque `[2 x <8 x i8>]`, with this PR it is instead `[2 x <4 x i16>]`. That change is not relevant for the ABI, but using the correct type prevents bitcasts that can (indeed, do) confuse the LLVM pattern matcher.
This change will make it possible to implement the deinterleaving loads on AArch64 in a portable way (without neon-specific intrinsics), which means that e.g. Miri or the cranelift backend can run them without additional support.
discussion at [#t-compiler > loss of vector element type information](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/loss.20of.20vector.20element.20type.20information/with/584483611)
Implement `-Z allow-partial-mitigations` (RFC 3855)
This implements `-Z allow-partial-mitigations` as an unstable option, currently with support for control-flow-guard and stack-protector.
As a difference from the RFC, we have `-Z allow-partial-mitigations=!foo` rather than `-Z deny-partial-mitigations=foo`, since I couldn't find an easy way to have an allow/deny pair of flags where the latter flag wins.
To allow for stabilization, this is only enabled starting from the next edition. Maybe a better policy is possible (bikeshed).
r? @rcvalle
The bcdtor mode affects how the AIX linker choose to pull in static constructors and destructors (https://www.ibm.com/docs/en/aix/7.2.0?topic=l-ld-command) to the link.
The current setting of all makes static init in archive members live regardless of if the archive member would be otherwise referenced, causing that whole archive member to become part of the link.
This default was initially retained for compatibility purposes with historical compilers on the platform which defaulted to this setting. Unfortunately this greedy pulling in of static init can have unintended consequences for applications, for example for programs linked against parts of compiler-rt which contain optional instrumentation (containing static initializers) which may be unused as these now become live in all programs regardless of use.
For that reason and similar reasons, this PR switches the default to mbr, which only extracts static init from archive members which would otherwise be referenced. This gives a behaviour very consistent with linkers on other platforms (e.g. Linux).
Users requiring the old default behaviour can manually pass -bcdtors:all on the link step which will override any default we pass here.
allow `windows-gnu` targets to embed gdb visualizer scripts
Pretty straigthforward, works exactly the same as any other `*-gnu` target so i'm not sure why it wasn't enabled already.
Hexagon: add scalar arch-version target features (v60-v79, audio)
Add target features corresponding to Hexagon LLVM CPU generations to complement the existing HVX vector features. These are needed for gating scalar intrinsics by architecture version.
New features: audio, v60, v62, v65, v66, v67, v68, v69, v71, v73, v75, v79
Each version implies the previous (e.g. v68 implies v67 which implies v66, etc.), matching LLVM's ArchV60-ArchV79 subtarget features.
Also adds hexagon revisions to the feature-hierarchy test to verify the implied feature chains work correctly.
Invert dependency between `rustc_errors` and `rustc_abi`.
Currently, `rustc_errors` depends on `rustc_abi`, which depends on `rustc_error_messages`. This is a bit odd.
`rustc_errors` depends on `rustc_abi` for a single reason: `rustc_abi` defines a type `TargetDataLayoutErrors` and `rustc_errors` impls `Diagnostic` for that type.
We can get a more natural relationship by inverting the dependency, moving the `Diagnostic` trait upstream. Then `rustc_abi` defines `TargetDataLayoutErrors` and also impls `Diagnostic` for it. `rustc_errors` is already pretty far upstream in the crate graph, it doesn't hurt to push it a little further because errors are a very low-level concept.
r? @davidtwco
Add target features corresponding to Hexagon LLVM CPU generations to
complement the existing HVX vector features. These are needed for
gating scalar intrinsics by architecture version.
New features: audio, v60, v62, v65, v66, v67, v68, v69, v71, v73, v75, v79
Each version implies the previous (e.g. v68 implies v67 which implies
v66, etc.), matching LLVM's ArchV60-ArchV79 subtarget features.
Also adds hexagon revisions to the feature-hierarchy test to verify
the implied feature chains work correctly.
This implements `-Z allow-partial-mitigations` as an unstable option,
currently with support for control-flow-guard and stack-protector.
As a difference from the RFC, we have `-Z allow-partial-mitigations=!foo`
rather than `-Z deny-partial-mitigations=foo`, since I couldn't find an easy
way to have an allow/deny pair of flags where the latter flag wins.
To allow for stabilization, this is only enabled starting from the next edition. Maybe a
better policy is possible (bikeshed).
rustc: Stop passing `--allow-undefined` on wasm targets
This commit updates how the linker is invoked on WebAssembly targets (all of them) to avoid passing the `--allow-undefined` flag to the linker. Historically, if I remember this correctly, when `wasm-ld` was first integrated this was practically required because at the time it was otherwise impossible to import a function from the host into a wasm binary. Or, at least, I'm pretty sure that was why this was added.
At the time, as the documentation around this option indicates, it was known that this was going to be a hazard. This doesn't match behavior on native, for example, and can easily paper over what should be a linker error with some sort of other obscure runtime error. An example is that this program currently compiles and links, it just prints null:
unsafe extern "C" {
static nonexistent: u8;
}
fn main() {
println!("{:?}", &raw const nonexistent);
}
This can easily lead to mistakes like rust-lang/libc#4880 and defer what should be a compile-time link error to weird or unusual behavior at link time. Additionally, in the intervening time since `wasm-ld` was first introduced here, lots has changed and notably this program works as expected:
#[link(wasm_import_module = "host")]
unsafe extern "C" {
fn foo();
}
fn main() {
unsafe {
foo();
}
}
This continues to compile without error and the final wasm binary indeed has an imported function from the host. This program:
unsafe extern "C" {
fn foo();
}
fn main() {
unsafe {
foo();
}
}
this currently compiles successfully and emits an import from the `env` module. After this change, however, this will fail to compile with a link error stating that the `foo` symbol is not defined.
`derive(HashStable_Generic)` generates impls like this:
```
impl<__CTX> HashStable<__CTX> for ExpnKind
where
__CTX: crate::HashStableContext
{
fn hash_stable(&self, hcx : &mut __CTX, __hasher: &mut StableHasher) {
...
}
}
```
This is used for crates that are upstream of `rustc_middle`.
The `crate::HashStableContext` bound means every crate that uses
`derive(HashStable_Generic)` must provide (or import) a trait
`HashStableContext` which `rustc_middle` then impls. In `rustc_span`
this trait is sensible, with three methods. In other crates, this trait
is empty, and there is the following trait hierarchy:
```
rustc_session::HashStableContext
| |
| rustc_hir::HashStableContext
| / \
rustc_ast::HashStableContext rustc_abi::HashStableContext
|
rustc_span::HashStableContext
```
All very strange and unnecessary. This commit changes
`derive(HashStable_Generic)` to use `rustc_span::HashStableContext`
instead of `crate::HashStableContext`. This eliminates the need for all
the empty `HashStableContext` traits and impls. Much better.
specifically this emits an error when
- a custom target is used
- `RiscV32 if self.llvm_abiname == "ilp32e"` this abi is used for 32-bit
embedded targets, and clang/llvm document that the ABI may change in
the future.
Error enum names should not be plural. Even though there are multiple
possible errors, each instance of an error enum describes a single
error. There are dozens of singular error enum names, and only two
plural error enum names. This commit makes them both singular.
Pass -pg to linker when using -Zinstrument-mcount
This selects a slightly different crt on gnu targets which enables the profiler within glibc.
This makes using gprof a little easier with Rust binaries. Otherwise, rustc must be passed `-Clink-args=-pg` to ensure the correct startup code is linked.
Add x86_64-unknown-linux-gnu{m,t}san target which enables {M,T}San by default
Analogous to the ASan target (https://github.com/rust-lang/rust/pull/149644), this adds targets for MSan and TSan.
As suggested, in order to distribute sanitizer instrumented standard libraries without introducing new rustc flags, this adds a new dedicated target. With the target, we can distribute the instrumented standard libraries through a separate rustup component.
> A tier 2 target must have value to people other than its maintainers. (It may still be a niche target, but it must not be exclusively useful for an inherently closed group.)
The target is useful to anyone who wants to use MSan/TSan with a stable compiler or the ease to not have to recompiled all standard libraries for full coverage.
> A tier 2 target must have a designated team of developers (the “target maintainers”) available to consult on target-specific build-breaking issues, or if necessary to develop target-specific language or library implementation details. This team must have at least 2 developers.
> * The target maintainers should not only fix target-specific issues, but should use any such issue as an opportunity to educate the Rust community about portability to their target, and enhance documentation of the target.
I pledge myself and the folks from the Exploit Mitigations Project Group (rcvalle@ & 1c3t3a@) as target maintainers to fix target-specific issues and educate the Rust community about their use.
> The target must not place undue burden on Rust developers not specifically concerned with that target. Rust developers are expected to not gratuitously break a tier 2 target, but are not expected to become experts in every tier 2 target, and are not expected to provide target-specific implementations for every tier 2 target.
Understood. The target should not have negative impact for anyone not using it.
> The target must provide documentation for the Rust community explaining how to build for the target using cross-compilation, and explaining how to run tests for the target. If at all possible, this documentation should show how to run Rust programs and tests for the target using emulation, to allow anyone to do so. If the target cannot be feasibly emulated, the documentation should explain how to obtain and work with physical hardware, cloud systems, or equivalent.
`src/doc/rustc/src/platform-support/x86_64-unknown-linux-gnu{m,t}san.md` should provide the necessary documentation on how to build the target or compile programs with it. In the way the target can be emulated it should not differ from the tier 1 target `x86_64-unknown-linux-gnu`.
> The target must document its baseline expectations for the features or versions of CPUs, operating systems, libraries, runtime environments, and similar.
The baseline expectation mirror `x86_64-unknown-linux-gnu`.
> If introducing a new tier 2 or higher target that is identical to an existing Rust target except for the baseline expectations for the features or versions of CPUs, operating systems, libraries, runtime environments, and similar, then the proposed target must document to the satisfaction of the approving teams why the specific difference in baseline expectations provides sufficient value to justify a separate target.
> * Note that in some cases, based on the usage of existing targets within the Rust community, Rust developers or a target’s maintainers may wish to modify the baseline expectations of a target, or split an existing target into multiple targets with different baseline expectations. A proposal to do so will be treated similarly to the analogous promotion, demotion, or removal of a target, according to this policy, with the same team approvals required.
> * For instance, if an OS version has become obsolete and unsupported, a target for that OS may raise its baseline expectations for OS version (treated as though removing a target corresponding to the older versions), or a target for that OS may split out support for older OS versions into a lower-tier target (treated as though demoting a target corresponding to the older versions, and requiring justification for a new target at a lower tier for the older OS versions).
This has been outlined sufficiently. We should not enable MSan/TSan in the default target and are therefore creating a new tier 2 target to bridge the gap until `build-std` stabilized.
> Tier 2 targets must not leave any significant portions of core or the standard library unimplemented or stubbed out, unless they cannot possibly be supported on the target.
> * The right approach to handling a missing feature from a target may depend on whether the target seems likely to develop the feature in the future. In some cases, a target may be co-developed along with Rust support, and Rust may gain new features on the target as that target gains the capabilities to support those features.
> * As an exception, a target identical to an existing tier 1 target except for lower baseline expectations for the OS, CPU, or similar, may propose to qualify as tier 2 (but not higher) without support for std if the target will primarily be used in no_std applications, to reduce the support burden for the standard library. In this case, evaluation of the proposed target’s value will take this limitation into account.
All of std that is supported by `x86_64-unknown-linux-gnu` is also supported.
> The code generation backend for the target should not have deficiencies that invalidate Rust safety properties, as evaluated by the Rust compiler team. (This requirement does not apply to arbitrary security enhancements or mitigations provided by code generation backends, only to those properties needed to ensure safe Rust code cannot cause undefined behavior or other unsoundness.) If this requirement does not hold, the target must clearly and prominently document any such limitations as part of the target’s entry in the target tier list, and ideally also via a failing test in the testsuite. The Rust compiler team must be satisfied with the balance between these limitations and the difficulty of implementing the necessary features.
> * For example, if Rust relies on a specific code generation feature to ensure that safe code cannot overflow the stack, the code generation for the target should support that feature.
> * If the Rust compiler introduces new safety properties (such as via new capabilities of a compiler backend), the Rust compiler team will determine if they consider those new safety properties a best-effort improvement for specific targets, or a required property for all Rust targets. In the latter case, the compiler team may require the maintainers of existing targets to either implement and confirm support for the property or update the target tier list with documentation of the missing property.
The entire point is to have more security instead of less ;) The safety properties provided are already present in the compiler, just not enabled by default.
> If the target supports C code, and the target has an interoperable calling convention for C code, the Rust target must support that C calling convention for the platform via extern "C". The C calling convention does not need to be the default Rust calling convention for the target, however.
Understood.
> The target must build reliably in CI, for all components that Rust’s CI considers mandatory.
Understood and the reason for introducing the tier 2 target.
> The approving teams may additionally require that a subset of tests pass in CI, such as enough to build a functional “hello world” program, ./x.py test --no-run, or equivalent “smoke tests”. In particular, this requirement may apply if the target builds host tools, or if the tests in question provide substantial value via early detection of critical problems.
Understood.
> Building the target in CI must not take substantially longer than the current slowest target in CI, and should not substantially raise the maintenance burden of the CI infrastructure. This requirement is subjective, to be evaluated by the infrastructure team, and will take the community importance of the target into account.
Understood.
> Tier 2 targets should, if at all possible, support cross-compiling. Tier 2 targets should not require using the target as the host for builds, even if the target supports host tools.
Understood. No need to use this target as the host (no benefit of having MSan/TSan enabled for compiling).
> In addition to the legal requirements for all targets (specified in the tier 3 requirements), because a tier 2 target typically involves the Rust project building and supplying various compiled binaries, incorporating the target and redistributing any resulting compiled binaries (e.g. built libraries, host tools if any) must not impose any onerous license requirements on any members of the Rust project, including infrastructure team members and those operating CI systems. This is a subjective requirement, to be evaluated by the approving teams.
> * As an exception to this, if the target’s primary purpose is to build components for a Free and Open Source Software (FOSS) project licensed under “copyleft” terms (terms which require licensing other code under compatible FOSS terms), such as kernel modules or plugins, then the standard libraries for the target may potentially be subject to copyleft terms, as long as such terms are satisfied by Rust’s existing practices of providing full corresponding source code. Note that anything added to the Rust repository itself must still use Rust’s standard license terms.
Understood, no legal differences between this target and `x86_64-unknown-linux-gnu`.
> Tier 2 targets must not impose burden on the authors of pull requests, or other developers in the community, to ensure that tests pass for the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on tests failing for the target. Do not send automated messages or notifications (via any medium, including via @) to a PR author or others involved with a PR regarding the PR breaking tests on a tier 2 target, unless they have opted into such messages.
> * Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
Understood.
> The target maintainers should regularly run the testsuite for the target, and should fix any test failures in a reasonably timely fashion.
Understood.
> All requirements for tier 3 apply.
Requirements for tier 3 are listed below.
> A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
I pledge to do my best maintaining it and we can also include the folks from the Exploit Mitigations Project Group (rcvalle@ & 1c3t3a@).
> Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
We've chosen `x86_64-unknown-linux-gnu{m,t}san` as the name which was suggested on [#t-compiler/major changes > Create new Tier 2 targets with sanitizers… compiler-team#951 @ 💬](https://rust-lang.zulipchat.com/#narrow/channel/233931-t-compiler.2Fmajor-changes/topic/Create.20new.20Tier.202.20targets.20with.20sanitizers.E2.80.A6.20compiler-team.23951/near/564482315). We've merged `x86_64-unknown-linux-gnuasan` and are now following up with the MSan and TSan targets
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
There should be no confusion, it's clear that it's the original target with MSan/TSan enabled.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
Only letters, numbers and dashes used.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
There are no unusual requirements to build or use it. It's the original `x86_64-unknown-linux-gnu` target with MSan/TSan enabled as a default sanitizer.
> The target must not introduce license incompatibilities.
There are no license implications.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Given, by reusing the existing MSan/TSan code.
> The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
There are no new dependencies/features required.
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
It's using open source tools only.
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
There are no such terms present.
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
Understood.
> This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
Understood.
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
The goal is to have MSan/TSan instrumented standard library variants of the existing `x86_64-unknown-linux-gnu` target, so all should be present.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.
I think the explanation in platform support doc is enough to make this aspect clear.
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via @) to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
Understood.
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
Understood.
> In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
I don't believe this PR is affected by this.
> Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target. (Having support in a fork of the backend is not sufficient, it must be upstream.)
The target should work on all rustc versions that correctly compile for `x86_64-unknown-linux-gnu`.
Require avxvnni for avx10.2
AVX10.2 supports masked (and 512-bit) versions of some intrinsics available in AVXVNNI, AVXVNNIINT8 and AVXVNNIINT16 (e.g. AVX10.2 introduces `_mm{,256,512}_{mask{z}}_dpbuud_epi32` corresponding to `_mm{,256}_dpbuud_epi32` from AVXVNNIINT8). But Intel (being Intel), didn't (at least not in SDM) enforce that AVX10.2 (or at least AVX10_VNNI_INT, which is a "discrete AVX10 feature", introduced alongside AVX10.2, and expected to house more such instructions) requires AVXVNNI etc.
To make this (admittedly very Intel) situation a bit better, we can just require these features from the Rust frontend
r? @Amanieu
This also corrects a mistake in std-detect which allowed AVX10 to be enabled without AVX512F, in the (odd) case when F16C or FMA are not available (we require these for AVX512F because otherwise the LLVM assembler doesn't work)
Add `-Zsanitize=kernel-hwaddress`
The Linux kernel has a config option called `CONFIG_KASAN_SW_TAGS` that enables `-fsanitize=kernel-hwaddress`. This is not supported by Rust.
One slightly awkward detail is that `#[sanitize(address = "off")]` applies to both `-Zsanitize=address` and `-Zsanitize=kernel-address`. Probably it was done this way because both are the same LLVM pass. I replicated this logic here for hwaddress, but it might be undesirable.
Note that `#[sanitize(kernel_hwaddress = "off")]` could be supported as an annotation on statics, but since it's also missing for `#[sanitize(hwaddress = "off")]`, I did not add it.
MCP: https://github.com/rust-lang/compiler-team/issues/975
Tracking issue: https://github.com/rust-lang/rust/issues/154171
cc @rcvalle @maurer @ojeda
Nicholas Nethercote