Enable stack probes on aarch64 for LLVM 18
I tested this on `aarch64-unknown-linux-gnu` with LLVM main (~18).
cc #77071, to be closed once we upgrade our LLVM submodule.
Add new targets {x86_64,i686}-win7-windows-msvc
This PR adds two new Tier 3 targets, x86_64-win7-windows-msvc and i686-win7-windows-msvc, that aim to support targeting Windows 7 after the `*-pc-windows-msvc` target drops support for it (slated to happen in 1.76.0).
# Tier 3 target policy
> At this tier, the Rust project provides no official support for a target, so we place minimal requirements on the introduction of targets.
>
> A proposed new tier 3 target must be reviewed and approved by a member of the compiler team based on these requirements. The reviewer may choose to gauge broader compiler team consensus via a [Major Change Proposal (MCP)](https://forge.rust-lang.org/compiler/mcp.html).
>
> A proposed target or target-specific patch that substantially changes code shared with other targets (not just target-specific code) must be reviewed and approved by the appropriate team for that shared code before acceptance.
>
> - 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.)
This is me, `@roblabla` on github.
> - 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.
I went with naming the target `x86_64-win7-windows-msvc`, inserting the `win7` in the vendor field (usually set to to `pc`). This is done to avoid ecosystem churn, as quite a few crates have `cfg(target_os = "windows")` or `cfg(target_env = "msvc")`, but nearly no `cfg(target_vendor = "pc")`. Since my goal is to be able to seamlessly swap to the `win7` target, I figured it'd be easier this way.
> - 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.
I believe the naming is pretty explicit.
> - If possible, use only letters, numbers, dashes and underscores for the name. Periods (`.`) are known to cause issues in Cargo.
The name comforms to this requirement.
> - 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.
> - The target must not introduce license incompatibilities.
> - Anything added to the Rust repository must be under the standard Rust license (`MIT OR Apache-2.0`).
> - 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.
> - 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.
> - "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.
As far as I understand it, this target has exactly the same legal situation as the existing Tier 1 x86_64-pc-windows-msvc.
> - 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.
> - 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.
This target supports the whole libstd surface, since it's essentially reusing all of the x86_64-pc-windows-msvc target. Understood.
> - 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.
Wrote some documentation on how to build, test and cross-compile the target in the `platform-support` part. Hopefully it's enough to get started.
> - 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.
> - 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.
Understood.
> If a tier 3 target stops meeting these requirements, or the target maintainers no longer have interest or time, or the target shows no signs of activity and has not built for some time, or removing the target would improve the quality of the Rust codebase, we may post a PR to remove it; any such PR will be CCed to the target maintainers (and potentially other people who have previously worked on the target), to check potential interest in improving the situation.
Understood.
Add emulated TLS support
This is a reopen of https://github.com/rust-lang/rust/pull/96317 . many android devices still only use 128 pthread keys, so using emutls can be helpful.
Currently LLVM uses emutls by default for some targets (such as android, openbsd), but rust does not use it, because `has_thread_local` is false.
This commit has some changes to allow users to enable emutls:
1. add `-Zhas-thread-local` flag to specify that std uses `#[thread_local]` instead of pthread key.
2. when using emutls, decorate symbol names to find thread local symbol correctly.
3. change `-Zforce-emulated-tls` to `-Ztls-model=emulated` to explicitly specify whether to generate emutls.
r? `@Amanieu`
These files were added to the repository but never wired up so they could
be used - and that was a few years ago without anyone noticing - so let's
remove these, they can be re-added if someone wants them.
Signed-off-by: David Wood <david@davidtw.co>
`riscv32` platform support
This PR adds the following RISCV targets to the tier 2 list of targets:
- riscv32imafc-unknown-none-elf
- riscv32im-unknown-none-elf
The rationale behind adding them directly to tier 2, is that the other bare metal targets already exist at tier 2, and these new targets are the same with an additional target feature enabled.
As well as the additional targets, this PR fills out the platform support document(s) that were previously missing.
~~The RISC-V bare metal targets don't currently have a platform support document, but this will change soon as the RISC-V team from the Rust-embedded working group will maintain these once https://github.com/davidtwco/rust/pull/1 is merged (and `@davidtwco's` upstream PR is merged after). For the time being you can cc myself or any other member of the RISC-V team: https://github.com/orgs/rust-embedded/teams/riscv.~~
> 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.)
RISC-V is an open specification, used and accessible to anyone including individuals.
> 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.
This rust-embedded working group's [RISCV team](https://github.com/orgs/rust-embedded/teams/riscv) will maintain these targets.
> 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.
I don't forsee this being an issue, the RISCV team will ensure we avoid undue burden for the general Rust community.
> 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.
There are links to resources we maintain in the re wg org in the platform support document.
> The target must document its baseline expectations for the features or versions of CPUs, operating systems, libraries, runtime environments, and similar.
Documented in the platform support document.
> 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.
New target features in RISCV can drastically change the capability of a CPU, hence the need for a separate target to support different variants. We aim to support any ratified RISCV extensions.
> 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.
`core` is fully implemented.
> 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.
RISCV is a well-established and well-maintained LLVM backend. To the best of my knowledge, the backend won't cause the generated code to have undefined behaviour.
> 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.
The C calling convention is supported by RISCV.
> The target must build reliably in CI, for all components that Rust's CI considers mandatory.
For the last 4-5 years many of these RISCV targets have been building in CI without any known issues.
> 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.
Not applicable, in the future we may wish to add qemu tests but this is out of scope for now.
> 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.
To the best of my knowledge, this will not induce a burden on the current CI infra.
> 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.
Cross-compilation is supported and documented in the platform support document.
> 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.
There are no additional license issues to worry about.
> 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.
The RISCV team agrees not to do this.
> The target maintainers should regularly run the testsuite for the target, and should fix any test failures in a reasonably timely fashion.
The RISCV team will fix any issues in a timely manner.
Currently LLVM uses emutls by default
for some targets (such as android, openbsd),
but rust does not use it, because `has_thread_local` is false.
This commit has some changes to allow users to enable emutls:
1. add `-Zhas-thread-local` flag to specify
that std uses `#[thread_local]` instead of pthread key.
2. when using emutls, decorate symbol names
to find thread local symbol correctly.
3. change `-Zforce-emulated-tls` to `-Ztls-model=emulated`
to explicitly specify whether to generate emutls.
Use `unwinding` crate for unwinding on Xous platform
This patch adds support for using [unwinding](https://github.com/nbdd0121/unwinding) on platforms where libunwinding isn't viable. An example of such a platform is `riscv32imac-unknown-xous-elf`.
### Background
The Rust project maintains a fork of llvm at [llvm-project](https://github.com/rust-lang/llvm-project/) where it applies patches on top of the llvm project. This mostly seems to be to get unwinding support for the SGX project, and there may be other patches that I'm unaware of.
There is a lot of machinery in the build system to support compiling `libunwind` on other platforms, and I needed to add additional patches to llvm in order to add support for Xous.
Rather than continuing down this path, it seemed much easier to use a Rust-based library. The `unwinding` crate by `@nbdd0121` fits this description perfectly.
### Future work
This could potentially replace the custom patches for `libunwind` on other platforms such as SGX, and could enable unwinding support on many more exotic platforms.
### Anti-goals
This is not designed to replace `libunwind` on tier-one platforms or those where unwinding support already exists. There is already a well-established approach for unwinding there. Instead, this aims to enable unwinding on new platforms where C++ code may be difficult to compile.
Enable the Arm Cortex-A53 errata mitigation on aarch64-unknown-none
Arm Cortex-A53 CPUs have an errata related to a specific sequence of instructions - errata number 843419 (https://documentation-service.arm.com/static/5fa29fddb209f547eebd361d). There is a mitigation that can be applied at link-time which detects the when sequence of instructions exists at a specific alignment. When detected, the linker re-writes those instructions and either changes an ADRP to an ADR, or bounces to a veneer to break the sequence.
The linker argument to enable the mitigation is "--fix-cortex-a53-843419", and this is supported by GNU ld and LLVM lld. The gcc argument to enable the flag is "-mfix-cortex-a53-843419".
Because the aarch64-unknown-none target uses rust-lld directly, this patch causes rustc to emit the "--fix-cortex-a53-843419" argument when calling the linker, just like aarch64-linux-gnu-gcc on Ubuntu 22.04 does.
Failure to enable this mitigation in the linker can cause the production of instruction sequences that do not execute correctly on Arm Cortex-A53.
By default, `newtype_index!` types get a default `Encodable`/`Decodable`
impl. You can opt out of this with `custom_encodable`. Opting out is the
opposite to how Rust normally works with autogenerated (derived) impls.
This commit inverts the behaviour, replacing `custom_encodable` with
`encodable` which opts into the default `Encodable`/`Decodable` impl.
Only 23 of the 59 `newtype_index!` occurrences need `encodable`.
Even better, there were eight crates with a dependency on
`rustc_serialize` just from unused default `Encodable`/`Decodable`
impls. This commit removes that dependency from those eight crates.
Arm Cortex-A53 CPUs have an errata related to a specific sequence of instructions - errata number 843419 (https://documentation-service.arm.com/static/5fa29fddb209f547eebd361d). There is a mitigation that can be applied at link-time which detects the when sequence of instructions exists at a specific alignment. When detected, the linker re-writes those instructions and either changes an ADRP to an ADR, or bounces to a veneer to break the sequence.
The linker argument to enable the mitigation is "--fix-cortex-a53-843419", and this is supported by GNU ld and LLVM lld. The gcc argument to enable the flag is "-mfix-cortex-a53-843419".
Because the aarch64-unknown-none target uses rust-lld directly, this patch causes rustc to emit the "--fix-cortex-a53-843419" argument when calling the linker, just like aarch64-linux-gnu-gcc on Ubuntu 22.04 does.
Failure to enable this mitigation in the linker can cause the production of instruction sequences that do not execute correctly on Arm Cortex-A53.
Add arm64e-apple-ios & arm64e-apple-darwin targets
This introduces
* `arm64e-apple-ios`
* `arm64e-apple-darwin`
Rust targets for support `arm64e` architecture on `iOS` and `Darwin`.
So, this is a first approach for integrating to the Rust compiler.
## Tier 3 Target Policy
> * 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 will be the target maintainer.
> * 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.
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.
If possible, use only letters, numbers, dashes and underscores for the name.
Periods (.) are known to cause issues in Cargo.
The target names `arm64e-apple-ios`, `arm64e-apple-darwin` were derived from `aarch64-apple-ios`, `aarch64-apple-darwin`.
In this [ticket,](#73628) people discussed the best suitable names for these targets.
> In some cases, the arm64e arch might be "different". For example:
> * `thread_set_state` might fail with (os/kern) protection failure if we try to call it from arm64 process to arm64e process.
> * The returning value of dlsym is PAC signed on arm64e, while left untouched on arm64
> * Some function like pthread_create_from_mach_thread requires a PAC signed function pointer on arm64e, which is not required on arm64.
So, I have chosen them because there are similar triplets in LLVM. I think there are no more suitable names for these targets.
> * 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.
The target must not introduce license incompatibilities.
Anything added to the Rust repository must be under the standard Rust
license (MIT OR Apache-2.0).
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.
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.
"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.
No dependencies were added to Rust.
> * 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.
> * 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.
I am not a member of a Rust team.
> * 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.
Understood.
`std` is supported.
> * 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.
Building is described in the derived target doc.
> * 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.
> * 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.
These targets are not fully ABI compatible with arm64e code.
#73628
Ensure sanity of all computed ABIs
This moves the ABI sanity assertions from the codegen backend to the ABI computation logic. Sadly, due to past mistakes, we [have to](https://github.com/rust-lang/rust/pull/117351#issuecomment-1788495503) be able to compute a sane ABI for nonsensical function types like `extern "C" fn(str) -> str`. So to make the sanity check pass we first need to make all ABI adjustment deal with unsized types... and we have no shared infrastructure for those adjustments, so that's a bunch of copy-paste. At least we have assertions failing loudly when one accidentally sets a different mode for an unsized argument.
To achieve this, this re-lands the parts of https://github.com/rust-lang/rust/pull/80594 that got reverted in https://github.com/rust-lang/rust/pull/81388. To avoid breaking wasm ABI again, that ABI now explicitly opts-in to the (wrong, broken) ABI that we currently keep for backwards compatibility. That's still better than having *every* ABI use the wrong broken default!
Cc `@bjorn3`
Fixes https://github.com/rust-lang/rust/issues/115845
Remove asmjs
Fulfills [MCP 668](https://github.com/rust-lang/compiler-team/issues/668).
`asmjs-unknown-emscripten` does not work as-specified, and lacks essential upstream support for generating asm.js, so it should not exist at all.
Add `std:#️⃣:{DefaultHasher, RandomState}` exports (needs FCP)
This implements rust-lang/libs-team#267 to move the libstd hasher types to `std::hash` where they belong, instead of `std::collections::hash_map`.
<details><summary>The below no longer applies, but is kept for clarity.</summary>
This is a small refactor for #27242, which moves the definitions of `RandomState` and `DefaultHasher` into `std::hash`, but in a way that won't be noticed in the public API.
I've opened rust-lang/libs-team#267 as a formal ACP to move these directly into the root of `std::hash`, but for now, they're at least separated out from the collections code in a way that will make moving that around easier.
I decided to simply copy the rustdoc for `std::hash` from `core::hash` since I think it would be ideal for the two to diverge longer-term, especially if the ACP is accepted. However, I would be willing to factor them out into a common markdown document if that's preferred.
</details>
Set max_atomic_width for riscv32*-esp-espidf to 32
Fixes#117305
> Since riscv32 does not have 64-bit atomic instructions, I do not believe there is any way to fix this problem other than setting max_atomic_width of these targets to 32.
This is a breaking change because Atomic\*64 will become unavailable, but all affected targets are tier 3, and the current Atomic*64 violates the standard library's API contract and can cause problems with code that rely on the standard library's atomic types being lock-free.
r? `@Amanieu`
cc `@ivmarkov` `@MabezDev`
- Sort dependencies and features sections.
- Add `tidy` markers to the sorted sections so they stay sorted.
- Remove empty `[lib`] sections.
- Remove "See more keys..." comments.
Excluded files:
- rustc_codegen_{cranelift,gcc}, because they're external.
- rustc_lexer, because it has external use.
- stable_mir, because it has external use.
Declare rustc_target's dependency on object/macho
Without this, `cargo check` fails in crates that depend on rustc_target.
<details>
<summary>`cargo check` diagnostics</summary>
```console
Checking rustc_target v0.0.0
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:176:17
|
176 | object::macho::PLATFORM_MACOS => Some((13, 1)),
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:177:17
|
177 | object::macho::PLATFORM_IOS
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:178:19
|
178 | | object::macho::PLATFORM_IOSSIMULATOR
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:179:19
|
179 | | object::macho::PLATFORM_TVOS
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:180:19
|
180 | | object::macho::PLATFORM_TVOSSIMULATOR
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:181:19
|
181 | | object::macho::PLATFORM_MACCATALYST => Some((16, 2)),
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:182:17
|
182 | object::macho::PLATFORM_WATCHOS | object::macho::PLATFORM_WATCHOSSIMULATOR => Some((9, 1)),
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:182:51
|
182 | object::macho::PLATFORM_WATCHOS | object::macho::PLATFORM_WATCHOSSIMULATOR => Some((9, 1)),
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:189:33
|
189 | ("macos", _) => object::macho::PLATFORM_MACOS,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:190:38
|
190 | ("ios", "macabi") => object::macho::PLATFORM_MACCATALYST,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:191:35
|
191 | ("ios", "sim") => object::macho::PLATFORM_IOSSIMULATOR,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:192:31
|
192 | ("ios", _) => object::macho::PLATFORM_IOS,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:193:39
|
193 | ("watchos", "sim") => object::macho::PLATFORM_WATCHOSSIMULATOR,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:194:35
|
194 | ("watchos", _) => object::macho::PLATFORM_WATCHOS,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:195:36
|
195 | ("tvos", "sim") => object::macho::PLATFORM_TVOSSIMULATOR,
| ^^^^^ could not find `macho` in `object`
error[E0433]: failed to resolve: could not find `macho` in `object`
--> compiler/rustc_target/src/spec/apple_base.rs:196:32
|
196 | ("tvos", _) => object::macho::PLATFORM_TVOS,
| ^^^^^ could not find `macho` in `object`
```
</details>
`rustc_target` unconditionally contains its `spec` module (i.e. there is no `#[cfg]` on the `mod spec;`). The `spec/mod.rs` also does not start with `#![cfg]`.
aa91057796/compiler/rustc_target/src/lib.rs (L37)
Similarly, the `spec` module unconditionally contains `apple_base`.
aa91057796/compiler/rustc_target/src/spec/mod.rs (L62)
And, `apple_base` unconditionally refers to `object::macho`.
aa91057796/compiler/rustc_target/src/spec/apple_base.rs (L176)
So I figure there is no way `object::macho` isn't needed by rustc.
`object::macho` only exists if the `object` crate's "macho" feature is enabled. https://github.com/gimli-rs/object/blob/0.32.0/src/lib.rs#L111-L112
Add support for i586-unknown-netbsd as target.
This restricts instructions to those offered by Pentium, to support e.g. AMD Geode.
There is already an entry for this target in the NetBSD platform support page at
src/doc/rustc/src/platform-support/netbsd.md
...so this should forestall its removal.
Additional fixes are needed for some vendored modules, this is the changes in the rust compiler core itself.
tvOS simulator support on Apple Silicon for rustc
Closes or is a subtask of #115692.
# Tier 3 Target Policy
At this tier, the Rust project provides no official support for a target, so we place minimal requirements on the introduction of targets.
> * 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.)
See [`src/doc/rustc/src/platform-support/apple-tvos.md`](4ab4d48ee5/src/doc/rustc/src/platform-support/apple-tvos.md)
> * 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.
> * 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.
> * If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
This naming scheme matches `$ARCH-$VENDOR-$OS-$ABI` (I think `sim` is the ABI here) which is matches the iOS apple silicon simulator (`aarch64-apple-ios-sim`). [There is some discussion about renaming some apple simulator targets](https://github.com/rust-lang/rust/issues/115692#issuecomment-1712931910) to match the `-sim` suffix but that is outside the scope of this PR.
> * 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.
>
> * The target must not introduce license incompatibilities.
> * Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
> * 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.
> * 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.
> * "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.
This contribution is fully available under the standard Rust license with no additional legal restrictions whatsoever. This PR does not introduce any new dependency less permissive than the Rust license policy.
The new targets do not depend on proprietary libraries.
> * 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.
This new target implements as much of the standard library as the other tvOS targets do.
> * 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 have added the target to the other tvOS targets in [`src/doc/rustc/src/platform-support/apple-tvos.md`](4ab4d48ee5/src/doc/rustc/src/platform-support/apple-tvos.md)
> * 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.
> * 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.
> * 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.
> * 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.
> * 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 acknowledge these requirements and intend to ensure that they are met.
This target does not touch any existing tier 2 or tier 1 targets and should not break any other targets.
This triggers a consistency check in rust (that all linker flavours
must have identical arguments), and on NetBSD/i386, the 32-bitness
is implicitly chosen through the chosen toolchain, and appears to
not be required. So drop it, and also drop the imports of the
now-no-longer-used identifiers.
Allow target specs to use an LLD flavor, and self-contained linking components
This PR allows:
- target specs to use an LLD linker-flavor: this is needed to switch `x86_64-unknown-linux-gnu` to using LLD, and is currently not possible because the current flavor json serialization fails to roundtrip on the modern linker-flavors. This can e.g. be seen in https://github.com/rust-lang/rust/pull/115622#discussion_r1321312880 which explains where an `Lld::Yes` is ultimately deserialized into an `Lld::No`.
- target specs to declare self-contained linking components: this is needed to switch `x86_64-unknown-linux-gnu` to using `rust-lld`
- adds an end-to-end test of a custom target json simulating `x86_64-unknown-linux-gnu` being switched to using `rust-lld`
- disables codegen backends from participating because they don't support `-Zgcc-ld=lld` which is the basis of mcp510.
r? `@petrochenkov:` if the approach discussed https://github.com/rust-lang/rust/pull/115622#discussion_r1329403467 and on zulip would work for you: basically, see if we can emit only modern linker flavors in the json specs, but accept both old and new flavors while reading them, to fix the roundtrip issue.
The backwards compatible `LinkSelfContainedDefault` variants are still serialized and deserialized in `crt-objects-fallback`, while the spec equivalent of e.g. `-Clink-self-contained=+linker` is serialized into a different json object (with future-proofing to incorporate `crt-objects-fallback` in the future).
---
I've been test-driving this in https://github.com/rust-lang/rust/pull/113382 to test actually switching `x86_64-unknown-linux-gnu` to `rust-lld` (and fix what needs to be fixed in CI, bootstrap, etc), and it seems to work fine.
This restricts instructions to those offered by Pentium,
to support e.g. AMD Geode.
There is already an entry for this target in the NetBSD
platform support page at
src/doc/rustc/src/platform-support/netbsd.md
...so this should forestall its removal.
Additional fixes are needed for some vendored modules, this
is the changes in the rust compiler core itself.
Removes the backwards-compatible `LinkSelfContainedDefault`, by
incorporating the remaining specifics into `LinkSelfContained`.
Then renames the modern options to keep the old name.
this ensures roundtripping of stable and unstable values:
- backwards-compatible values can be deserialized, as well as the new
unstable values
- unstable values are serialized.
It's a better name, and lets "active features" refer to the features
that are active in a particular program, due to being declared or
enabled by the edition.
The commit also renames `Features::enabled` as `Features::active` to
match this; I changed my mind and have decided that "active" is a little
better thatn "enabled" for this, particularly because a number of
pre-existing comments use "active" in this way.
Finally, the commit renames `Status::Stable` as `Status::Accepted`, to
match `ACCEPTED_FEATURES`.
Format all the let-chains in compiler crates
Since rust-lang/rustfmt#5910 has landed, soon we will have support for formatting let-chains (as soon as rustfmt syncs and beta gets bumped).
This PR applies the changes [from master rustfmt to rust-lang/rust eagerly](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/out.20formatting.20of.20prs/near/374997516), so that the next beta bump does not have to deal with a 200+ file diff and can remain concerned with other things like `cfg(bootstrap)` -- #113637 was a pain to land, for example, because of let-else.
I will also add this commit to the ignore list after it has landed.
The commands that were run -- I'm not great at bash-foo, but this applies rustfmt to every compiler crate, and then reverts the two crates that should probably be formatted out-of-tree.
```
~/rustfmt $ ls -1d ~/rust/compiler/* | xargs -I@ cargo run --bin rustfmt -- `@/src/lib.rs` --config-path ~/rust --edition=2021 # format all of the compiler crates
~/rust $ git checkout HEAD -- compiler/rustc_codegen_{gcc,cranelift} # revert changes to cg-gcc and cg-clif
```
cc `@rust-lang/rustfmt`
r? `@WaffleLapkin` or `@Nilstrieb` who said they may be able to review this purely mechanical PR :>
cc `@Mark-Simulacrum` and `@petrochenkov,` who had some thoughts on the order of operations with big formatting changes in https://github.com/rust-lang/rust/pull/95262#issue-1178993801. I think the situation has changed since then, given that let-chains support exists on master rustfmt now, and I'm fairly confident that this formatting PR should land even if *bootstrap* rustfmt doesn't yet format let-chains in order to lessen the burden of the next beta bump.
Implement `-Clink-self-contained=-linker` opt out
This implements the `-Clink-self-contained` opt out necessary to switch to lld by changing rustc's defaults instead of cargo's.
Components that are enabled and disabled on the CLI are recorded, for the purpose of being merged with the ones which the target spec will declare (I'll open another PR for that tomorrow, for easier review).
For MCP510, we now check whether using the self-contained linker is disabled on the CLI. Right now it would only be sensible to with `-Zgcc-ld=lld` (and I'll add some checks that we don't both enable and disable a component on the CLI in a future PR), but the goal is to simplify adding the check of the target's enabled components here in the follow-up PRs.
r? `@petrochenkov`
Bring back generic parameters for indices in rustc_abi and make it compile on stable
This effectively reverses https://github.com/rust-lang/rust/pull/107163, allowing rust-analyzer to depend on this crate again,
It also moves some glob imports / expands them in the first commit because they made it more difficult for me to reason about things.
Add Zba, Zbb, and Zbs as target features for riscv64-linux-android
This pull request adds the Zba, Zbb, and Zbs target features to the `riscv64-linux-android` target specification. These features have been enabled and tested internally in Android infrastructure.
Add Minimal Std implementation for UEFI
# Implemented modules:
1. alloc
2. os_str
3. env
4. math
# Related Links
Tracking Issue: https://github.com/rust-lang/rust/issues/100499
API Change Proposal: https://github.com/rust-lang/libs-team/issues/87
# Additional Information
This was originally part of https://github.com/rust-lang/rust/pull/100316. Since that PR was becoming too unwieldy and cluttered, and with suggestion from `@dvdhrm,` I have extracted a minimal std implementation to this PR.
The example in `src/doc/rustc/src/platform-support/unknown-uefi.md` has been tested for `x86_64-unknown-uefi` and `i686-unknown-uefi` in OVMF. It would be great if someone more familiar with AARCH64 can help with testing for that target.
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
Raise minimum supported Apple OS versions
This implements the proposal to raise the minimum supported Apple OS versions as laid out in the now-completed MCP (https://github.com/rust-lang/compiler-team/issues/556).
As of this PR, rustc and the stdlib now support these versions as the baseline:
- macOS: 10.12 Sierra
- iOS: 10
- tvOS: 10
- watchOS: 5 (Unchanged)
In addition to everything this breaks indirectly, these changes also erase the `armv7-apple-ios` target (currently tier 3) because the oldest supported iOS device now uses ARMv7s. Not sure what the policy around tier3 target removal is but shimming it is not an option due to the linker refusing.
[Per comment](https://github.com/rust-lang/compiler-team/issues/556#issuecomment-1297175073), this requires a FCP to merge. cc `@wesleywiser.`
The -macabi targets are iOS running on MacOS, and they use the runtime
libraries for MacOS, thus they have the same sanitizers available as the
*-apple-darwin targets.
Add `i686-pc-windows-gnullvm` triple
With various fixes that are already present in the code, a fully working i686 target can join other targets in `*-windows-gnullvm` family. Again this will be mostly useful for MSYS2 right now but I plan to open MCP for providing at least prebuilt std for `windows-gnullvm` as the next step which will expand usability of these targets.
Tier 3 policy:
> 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, MSYS2 is one of interested consumers. Previously added `gnullvm` triples proved there is not much maintenance required.
> 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.
This triple name is consistent with other targets and was discussed at [`t-compiler/LLVM+mingw-w64 Windows targets`](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/LLVM.2Bmingw-w64.20Windows.20targets)
> 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.
I think the explanation in platform support doc is enough to make this aspect clear.
> 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.
It's using open source tools only.
> The target must not introduce license incompatibilities.
It's even more liberal than already existing `*-pc-windows-gnu`.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Understood.
> 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.
As previously said 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.
I'm not the reviewer here.
> 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.
Again I'm not the reviewer here.
> 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.
It seems to work, at least for cross compilation.
> 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.
Building is described in platform support doc, running tests doesn't work right now (without hacks) because Rust's build system doesn't seem to support testing targets built from `.json`.
Docs will be updated once this lands in beta allowing master branch to build and run tests without `.json` files.
> 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.
Understood.
> 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.
I believe I didn't break any other target.
> 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 think there are no such problems in this PR.
Always add LC_BUILD_VERSION for metadata object files
As of Xcode 15 Apple's linker has become a bit more strict about the warnings it produces. One of those new warnings requires all valid Mach-O object files in an archive to have a LC_BUILD_VERSION load command:
```
ld: warning: no platform load command found in 'ARCHIVE[arm64][2106](lib.rmeta)', assuming: iOS-simulator
```
This was already being done for Mac Catalyst so this change expands this logic to include it for all Apple platforms. I filed this behavior change as FB12546320 and was told it was the new intentional behavior.
Use `preserve_mostcc` for `extern "rust-cold"`
As experimentation in #115242 has shown looks better than `coldcc`. Notably, clang exposes `preserve_most` (https://clang.llvm.org/docs/AttributeReference.html#preserve-most) but not `cold`, so this change should put us on a better-supported path.
And *don't* use a different convention for cold on Windows, because that actually ends up making things worse. (See comment in the code.)
cc tracking issue #97544
This reverts commit 4410868798, reversing
changes made to 249595b752.
This causes linker failures with the binutils version used by
cross (#115239), as well as miscompilations when using the mold
linker.
As experimentation in 115242 has shown looks better than `coldcc`.
And *don't* use a different convention for cold on Windows, because that actually ends up making things worse.
cc tracking issue 97544
This option tells LLVM to emit relaxable relocation types
R_X86_64_GOTPCRELX/R_X86_64_REX_GOTPCRELX/R_386_GOT32X in applicable cases. True
matches Clang's CMake default since 2020-08 [1] and latest LLVM default[2].
This also works around a GNU ld<2.41 issue[3] when using
general-dynamic/local-dynamic TLS models in `-Z plt=no` mode with latest LLVM.
[1]: c41a18cf61
[2]: 2aedfdd9b8
[3]: https://sourceware.org/bugzilla/show_bug.cgi?id=24784
As of Xcode 15 Apple's linker has become a bit more strict about the
warnings it produces. One of those new warnings requires all valid
Mach-O object files in an archive to have a LC_BUILD_VERSION load
command:
```
ld: warning: no platform load command found in 'ARCHIVE[arm64][2106](lib.rmeta)', assuming: iOS-simulator
```
This was already being done for Mac Catalyst so this change expands this
logic to include it for all Apple platforms. I filed this behavior
change as FB12546320 and was told it was the new intentional behavior.
Replace the \01__gnu_mcount_nc to LLVM intrinsic for ARM
Current `-Zinstrument-mcount` for ARM32 use the `\01__gnu_mcount_nc` directly for its instrumentation function.
However, the LLVM does not use this mcount function directly, but it wraps it to intrinsic, `llvm.arm.gnu.eabi.mcount` and the transform pass also only handle the intrinsic.
As a result, current `-Zinstrument-mcount` not work on ARM32. Refer: https://github.com/namhyung/uftrace/issues/1764
This commit replaces the mcount name from native function to the LLVM intrinsic so that the transform pass can handle it.
Current `-Zinstrument-mcount` for ARM32 use the `\01__gnu_mcount_nc`
directly for its instrumentation function.
However, the LLVM does not use this mcount function directly, but it wraps
it to intrinsic, `llvm.arm.gnu.eabi.mcount` and the transform pass also
only handle the intrinsic.
As a result, current `-Zinstrument-mcount` not work on ARM32.
Refer: https://github.com/namhyung/uftrace/issues/1764
This commit replaces the mcount name from native function to the
LLVM intrinsic so that the transform pass can handle it.
Signed-off-by: ChoKyuWon <kyuwoncho18@gmail.com>
Infer `Lld::No` linker hint when the linker stem is a generic compiler driver
This PR basically reverts the temporary solution in https://github.com/rust-lang/rust/pull/113631 to a more long-term solution.
r? ``@petrochenkov``
In [this comment](https://github.com/rust-lang/rust/pull/113631#issuecomment-1634598238), you had ideas about a long-term solution:
> I wonder what a good non-temporary solution for the inference would look like.
>
> * If the default is `(Cc::No, Lld::Yes)` (e.g. `rust-lld`)
>
> * and we switch to some specific platform compiler (e.g. `-C linker=arm-none-eabi-gcc`), should we change to `Lld::No`? Maybe yes?
> * and we switch to some non-default but generic compiler `-C linker=clang`? Then maybe not?
>
> * If the default is `(Cc::Yes, Lld::Yes)` (e.g. future x86_64 linux with default LLD)
>
> * and we switch to some specific platform compiler (e.g. `-C linker=arm-none-eabi-gcc`), should we change to `Lld::No`? Maybe yes?
> * and we switch to some non-default but generic compiler `-C linker=clang`? Then maybe not?
>
I believe that we should infer the `Lld::No` linker hint for any `-Clinker` override, and all the cases above:
- the linker drivers have their own defaults, so in my mind `-Clinker` is a signal to use its default linker / flavor, rather than ours or the target's. In the case of generic compilers, it's more likely than not going to be `Lld::No`. I would expect this to be the case in general, even when including platform-specific compilers.
- the guess will be wrong if the linker driver uses lld by default (and we also don't want to search for `-fuse-ld` link args), but will work in the more common cases. And the minority of other cases can fix the wrong guess by opting into the precise linker flavor.
- this also ensures backwards-compatibility: today, even on targets with an lld default and overriding the linker, rustc will not use lld. That includes `thumbv6m-none-eabi` where issue #113597 happened.
It looks like the simplest option, and the one with least churn: we maintain the current behavior in ambiguous cases.
I've tested that this works on #113597, as expected from the failure.
(I also have a no-std `run-make` test using a custom target json spec: basically simulating a future `x86_64-unknown-linux-gnu` using an lld flavor by default, to check that e.g. `-Clinker=clang` doesn't use lld. I could add that test to this PR, but IIUC such a custom target requires `cargo -Z build-std` and we have no tests depending on this cargo feature yet. Let me know if you want to add this test of the linker inference for such targets.)
What do you think ?
Switch to LLD as default linker for loongarch64-unknown-none*
The [LLD already supports LoongArch](6084ee7420), it's time to switch to LLD as default linker for `loongarch64-unknown-none*`.
feat: `riscv-interrupt-{m,s}` calling conventions
Similar to prior support added for the mips430, avr, and x86 targets this change implements the rough equivalent of clang's [`__attribute__((interrupt))`][clang-attr] for riscv targets, enabling e.g.
```rust
static mut CNT: usize = 0;
pub extern "riscv-interrupt-m" fn isr_m() {
unsafe {
CNT += 1;
}
}
```
to produce highly effective assembly like:
```asm
pub extern "riscv-interrupt-m" fn isr_m() {
420003a0: 1141 addi sp,sp,-16
unsafe {
CNT += 1;
420003a2: c62a sw a0,12(sp)
420003a4: c42e sw a1,8(sp)
420003a6: 3fc80537 lui a0,0x3fc80
420003aa: 63c52583 lw a1,1596(a0) # 3fc8063c <_ZN12esp_riscv_rt3CNT17hcec3e3a214887d53E.0>
420003ae: 0585 addi a1,a1,1
420003b0: 62b52e23 sw a1,1596(a0)
}
}
420003b4: 4532 lw a0,12(sp)
420003b6: 45a2 lw a1,8(sp)
420003b8: 0141 addi sp,sp,16
420003ba: 30200073 mret
```
(disassembly via `riscv64-unknown-elf-objdump -C -S --disassemble ./esp32c3-hal/target/riscv32imc-unknown-none-elf/release/examples/gpio_interrupt`)
This outcome is superior to hand-coded interrupt routines which, lacking visibility into any non-assembly body of the interrupt handler, have to be very conservative and save the [entire CPU state to the stack frame][full-frame-save]. By instead asking LLVM to only save the registers that it uses, we defer the decision to the tool with the best context: it can more accurately account for the cost of spills if it knows that every additional register used is already at the cost of an implicit spill.
At the LLVM level, this is apparently [implemented by] marking every register as "[callee-save]," matching the semantics of an interrupt handler nicely (it has to leave the CPU state just as it found it after its `{m|s}ret`).
This approach is not suitable for every interrupt handler, as it makes no attempt to e.g. save the state in a user-accessible stack frame. For a full discussion of those challenges and tradeoffs, please refer to [the interrupt calling conventions RFC][rfc].
Inside rustc, this implementation differs from prior art because LLVM does not expose the "all-saved" function flavor as a calling convention directly, instead preferring to use an attribute that allows for differentiating between "machine-mode" and "superivsor-mode" interrupts.
Finally, some effort has been made to guide those who may not yet be aware of the differences between machine-mode and supervisor-mode interrupts as to why no `riscv-interrupt` calling convention is exposed through rustc, and similarly for why `riscv-interrupt-u` makes no appearance (as it would complicate future LLVM upgrades).
[clang-attr]: https://clang.llvm.org/docs/AttributeReference.html#interrupt-risc-v
[full-frame-save]: 9281af2ecf/src/lib.rs (L440-L469)
[implemented by]: b7fb2a3fec/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp (L61-L67)
[callee-save]: 973f1fe7a8/llvm/lib/Target/RISCV/RISCVCallingConv.td (L30-L37)
[rfc]: https://github.com/rust-lang/rfcs/pull/3246
Similar to prior support added for the mips430, avr, and x86 targets
this change implements the rough equivalent of clang's
[`__attribute__((interrupt))`][clang-attr] for riscv targets, enabling
e.g.
```rust
static mut CNT: usize = 0;
pub extern "riscv-interrupt-m" fn isr_m() {
unsafe {
CNT += 1;
}
}
```
to produce highly effective assembly like:
```asm
pub extern "riscv-interrupt-m" fn isr_m() {
420003a0: 1141 addi sp,sp,-16
unsafe {
CNT += 1;
420003a2: c62a sw a0,12(sp)
420003a4: c42e sw a1,8(sp)
420003a6: 3fc80537 lui a0,0x3fc80
420003aa: 63c52583 lw a1,1596(a0) # 3fc8063c <_ZN12esp_riscv_rt3CNT17hcec3e3a214887d53E.0>
420003ae: 0585 addi a1,a1,1
420003b0: 62b52e23 sw a1,1596(a0)
}
}
420003b4: 4532 lw a0,12(sp)
420003b6: 45a2 lw a1,8(sp)
420003b8: 0141 addi sp,sp,16
420003ba: 30200073 mret
```
(disassembly via `riscv64-unknown-elf-objdump -C -S --disassemble ./esp32c3-hal/target/riscv32imc-unknown-none-elf/release/examples/gpio_interrupt`)
This outcome is superior to hand-coded interrupt routines which, lacking
visibility into any non-assembly body of the interrupt handler, have to
be very conservative and save the [entire CPU state to the stack
frame][full-frame-save]. By instead asking LLVM to only save the
registers that it uses, we defer the decision to the tool with the best
context: it can more accurately account for the cost of spills if it
knows that every additional register used is already at the cost of an
implicit spill.
At the LLVM level, this is apparently [implemented by] marking every
register as "[callee-save]," matching the semantics of an interrupt
handler nicely (it has to leave the CPU state just as it found it after
its `{m|s}ret`).
This approach is not suitable for every interrupt handler, as it makes
no attempt to e.g. save the state in a user-accessible stack frame. For
a full discussion of those challenges and tradeoffs, please refer to
[the interrupt calling conventions RFC][rfc].
Inside rustc, this implementation differs from prior art because LLVM
does not expose the "all-saved" function flavor as a calling convention
directly, instead preferring to use an attribute that allows for
differentiating between "machine-mode" and "superivsor-mode" interrupts.
Finally, some effort has been made to guide those who may not yet be
aware of the differences between machine-mode and supervisor-mode
interrupts as to why no `riscv-interrupt` calling convention is exposed
through rustc, and similarly for why `riscv-interrupt-u` makes no
appearance (as it would complicate future LLVM upgrades).
[clang-attr]: https://clang.llvm.org/docs/AttributeReference.html#interrupt-risc-v
[full-frame-save]: 9281af2ecf/src/lib.rs (L440-L469)
[implemented by]: b7fb2a3fec/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp (L61-L67)
[callee-save]: 973f1fe7a8/llvm/lib/Target/RISCV/RISCVCallingConv.td (L30-L37)
[rfc]: https://github.com/rust-lang/rfcs/pull/3246
add aarch64-unknown-teeos target
TEEOS is a mini os run in TrustZone, for trusted/security apps. The libc of TEEOS is a part of musl. The kernel of TEEOS is micro kernel.
This MR is to add a target for teeos.
MRs for libc and rust-std are in progress.
Compiler team MCP: [MCP](https://github.com/rust-lang/compiler-team/issues/652)
Re-enable atomic loads and stores for all RISC-V targets
This roughly reverts PR https://github.com/rust-lang/rust/pull/66548
Atomic "CAS" are still disabled for targets without the *“A” Standard Extension for Atomic Instructions*. However this extension only adds instructions for operations more complex than simple loads and stores, which are always atomic when aligned.
In the [Unprivileged Spec v. 20191213](https://riscv.org/technical/specifications/) section 2.6 *Load and Store Instructions* of chapter 2 *RV32I Base Integer Instruction Set* (emphasis mine):
> Even when misaligned loads and stores complete successfully, these accesses might run extremely slowly depending on the implementation (e.g., when implemented via an invisible trap). Further-more, whereas **naturally aligned loads and stores are guaranteed to execute atomically**, misaligned loads and stores might not, and hence require additional synchronization to ensure atomicity.
Unfortunately PR https://github.com/rust-lang/rust/pull/66548 did not provide much details on the bug that motivated it, but https://github.com/rust-lang/rust/issues/66240 and https://github.com/rust-lang/rust/issues/85736 appear related and happen with targets that do have the A extension.
It lints against features that are inteded to be internal to the
compiler and standard library. Implements MCP #596.
We allow `internal_features` in the standard library and compiler as those
use many features and this _is_ the standard library from the "internal to the compiler and
standard library" after all.
Marking some features as internal wasn't exactly the most scientific approach, I just marked some
mostly obvious features. While there is a categorization in the macro,
it's not very well upheld (should probably be fixed in another PR).
We always pass `-Ainternal_features` in the testsuite
About 400 UI tests and several other tests use internal features.
Instead of throwing the attribute on each one, just always allow them.
There's nothing wrong with testing internal features^^
WASI threads, implementation of wasm32-wasi-preview1-threads target
This PR adds a target proposed in https://github.com/rust-lang/compiler-team/issues/574 by `@abrown` and implementation of `std:🧵:spawn` for the target `wasm32-wasi-preview1-threads`
### Tier 3 Target Policy
As tier 3 targets, the new targets are required to adhere to [the tier 3 target policy](https://doc.rust-lang.org/nightly/rustc/target-tier-policy.html#tier-3-target-policy) requirements. This section quotes each requirement in entirety and describes how they are met.
> - 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.)
See [src/doc/rustc/src/platform-support/wasm32-wasi-preview1-threads.md](https://github.com/rust-lang/rust/pull/112922/files#diff-a48ee9d94f13e12be24eadd08eb47b479c153c340eeea4ef22276d876dfd4f3e).
> - 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.
> - 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.
If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
The target is using the same name for $ARCH=wasm32 and $OS=wasi as existing Rust targets. The suffix `preview1` introduced to accurately set expectations because eventually this target will be deprecated and follows [MCP 607](https://github.com/rust-lang/compiler-team/issues/607). The suffix `threads` indicates that it’s an extension that enables threads to the existing target and it follows [MCP 574](https://github.com/rust-lang/compiler-team/issues/574) which describes the rationale behind introducing a separate target.
> - 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.
> - The target must not introduce license incompatibilities.
> - Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
> - 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.
> - 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.
> - "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.
This PR does not introduce any new dependency.
The new target doesn’t support building host tools.
> 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 full standard library is available for this target as it’s an extension to an existing target that has already supported it.
> 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.
Only manual test running is supported at the moment with some tweaks in the test runner codebase. For build and running tests see [src/doc/rustc/src/platform-support/wasm32-wasi-preview1-threads.md](https://github.com/rust-lang/rust/pull/112922/files#diff-a48ee9d94f13e12be24eadd08eb47b479c153c340eeea4ef22276d876dfd4f3e).
> - 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.
> - 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.
> - 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.
> - 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.
> - 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 acknowledge these requirements and intend to ensure they are met.
Add `x86_64-unikraft-linux-musl` target
This introduces `x86_64-unikraft-linux-musl` as the first Rust target for the [Unikraft] Unikernel Development Kit.
[Unikraft]: https://unikraft.org/
Unikraft imitates Linux and uses musl as libc.
It is extremely configurable, and does not even provide a `poll` implementation or a network stack, unless enabled by the end user who compiles the application.
Our approach for integrating the build process with `rustc` is to hide the build process as well as the actual final linking step behind a linker-shim (`kraftld`, see https://github.com/unikraft/kraftkit/issues/612).
## Tier 3 target policy
> - 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 will be the target maintainer.
> - 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.
> - 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.
> - If possible, use only letters, numbers, dashes and underscores for the name.
> Periods (`.`) are known to cause issues in Cargo.
The target name `x86_64-unikraft-linux-musl` was derived from `x86_64-unknown-linux-musl`, setting Unikraft as vendor.
Unikraft exactly imitates Linux + musl.
> - 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.
> - The target must not introduce license incompatibilities.
> - Anything added to the Rust repository must be under the standard Rust
> license (`MIT OR Apache-2.0`).
> - 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.
> - 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.
> - "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.
No dependencies were added to Rust.
Requirements for linking are [Unikraft] and [KraftKit] (both BSD-3-Clause), but none of these are added to Rust.
[KraftKit]: https://github.com/unikraft/kraftkit
> - 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.
> - 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.
I am not a member of a Rust team.
> - 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.
Understood.
`std` is supported.
> - 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.
Building is described in the platform support doc.
It will be updated once proper `kraftld` support has landed.
> - 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.
> - 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 think this PR breaks anything.
r? compiler-team
arm-none fixups
- Remove "-unknown" from `llvm_target` for arm\*v7r-none-eabi\* targets.
- Remove redundant `c_enum_min_bits` option from the thumbv4t-none-eabi target.
- Fix comments about GCC/Clang's enum width for arm-none targets.
Previously part of #110482, which is a larger change to add a new target.
These nits were found along the way.
These pre-link args are remains from Hermit's old C version.
We don't need them and we have no reason to override the defaults here.
See ld [1] for details.
[1]: https://sourceware.org/binutils/docs/ld/Options.html
Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
GCC uses the `-fshort-enums` ABI for arm-none and the `int`-sized enum
ABI for arm-linux.
Clang uses the `int`-sized enum ABI for all arm targets.
Both options are permitted by AAPCS.
Rust is matching GCC's behavior for these targets, as interop with code
code compiled by GCC is desirable in the bare-metal context. See #87917.
Rollup of 4 pull requests
Successful merges:
- #113887 (new solver: add a separate cache for coherence)
- #113910 (Add FnPtr ty to SMIR)
- #113913 (error/E0691: include alignment in error message)
- #113914 (rustc_target: drop duplicate code)
r? `@ghost`
`@rustbot` modify labels: rollup
Drop duplicate helper methods on `Layout`, which are already implemented
on `LayoutS`. Note that `Layout` has a `Deref` implementation to
`LayoutS`, so all accessors are automatically redirected.
The methods are identical and have been copied to `rustc_abi` in:
commit 390a637e29
Author: hamidreza kalbasi <hamidrezakalbasi@protonmail.com>
Date: Mon Nov 7 00:36:11 2022 +0330
move things from rustc_target::abi to rustc_abi
This commit left behind the original implementation. Drop it now.
Signed-off-by: David Rheinsberg <david@readahead.eu>
Add x86_64-unknown-linux-ohos target
This complements the existing `aarch64-unknown-linux-ohos` and `armv7-unknown-linux-ohos` targets.
This should be covered by the existing MCP (https://github.com/rust-lang/compiler-team/issues/568), but I can also create a new MCP if that is preferred.
Add a sparc-unknown-none-elf target.
# `sparc-unknown-none-elf`
**Tier: 3**
Rust for bare-metal 32-bit SPARC V7 and V8 systems, e.g. the Gaisler LEON3.
## Target maintainers
- Jonathan Pallant, `jonathan.pallant@ferrous-systems.com`, https://ferrous-systems.com
## Requirements
> Does the target support host tools, or only cross-compilation?
Only cross-compilation.
> Does the target support std, or alloc (either with a default allocator, or if the user supplies an allocator)?
Only tested with `libcore` but I see no reason why you couldn't also support `liballoc`.
> Document the expectations of binaries built for the target. Do they assume
specific minimum features beyond the baseline of the CPU/environment/etc? What
version of the OS or environment do they expect?
Tested by linking with a standard SPARC bare-metal toolchain - specifically I used the [BCC2] toolchain from Gaisler (both GCC and clang variants, both pre-compiled for x64 Linux and compiling my own SPARC GCC from source to run on `aarch64-apple-darwin`).
The target is set to use the lowest-common-denominator `SPARC V7` architecture (yes, they started at V7 - see [Wikipedia](https://en.wikipedia.org/wiki/SPARC#History)).
[BCC2]: https://www.gaisler.com/index.php/downloads/compilers
> Are there notable `#[target_feature(...)]` or `-C target-feature=` values that
programs may wish to use?
`-Ctarget-cpu=v8` adds the instructions added in V8.
`-Ctarget-cpu=leon3` adds the V8 instructions and sets up scheduling to suit the Gaisler LEON3.
> What calling convention does `extern "C"` use on the target?
I believe this is defined by the SPARC architecture reference manuals and V7, V8 and V9 are all compatible.
> What format do binaries use by default? ELF, PE, something else?
ELF
## Building the target
> If Rust doesn't build the target by default, how can users build it? Can users
just add it to the `target` list in `config.toml`?
Yes. I did:
```toml
target = ["aarch64-apple-darwin", "sparc-unknown-none-elf"]
```
## Building Rust programs
> Rust does not yet ship pre-compiled artifacts for this target. To compile for
this target, you will either need to build Rust with the target enabled (see
"Building the target" above), or build your own copy of `core` by using
`build-std` or similar.
Correct.
## Testing
> Does the target support running binaries, or do binaries have varying
expectations that prevent having a standard way to run them?
No - it's a bare metal platform.
> If users can run binaries, can they do so in some common emulator, or do they need native
hardware?
But if you use [BCC2] as the linker, you get default memory map suitable for the LEON3, and a default BSP for the LEON3, and so you can run the binaries in the `tsim-leon3` simulator from Gaisler.
```console
$ cat .cargo/config.toml | grep runner
runner = "tsim-leon3 -c sim-commands.txt"
$ cat sim-commands.txt
run
quit
$ cargo +sparcrust run --targe=sparc-unknown-none-elf
Compiling sparc-demo-rust v0.1.0 (/work/sparc-demo-rust)
Finished dev [unoptimized + debuginfo] target(s) in 3.44s
Running `tsim-leon3 -c sim-commands.txt target/sparc-unknown-none-elf/debug/sparc-demo-rust`
TSIM3 LEON3 SPARC simulator, version 3.1.9 (evaluation version)
Copyright (C) 2023, Frontgrade Gaisler - all rights reserved.
This software may only be used with a valid license.
For latest updates, go to https://www.gaisler.com/
Comments or bug-reports to support@gaisler.com
This TSIM evaluation version will expire 2023-11-28
Number of CPUs: 2
system frequency: 50.000 MHz
icache: 1 * 4 KiB, 16 bytes/line (4 KiB total)
dcache: 1 * 4 KiB, 16 bytes/line (4 KiB total)
Allocated 8192 KiB SRAM memory, in 1 bank at 0x40000000
Allocated 32 MiB SDRAM memory, in 1 bank at 0x60000000
Allocated 8192 KiB ROM memory at 0x00000000
section: .text, addr: 0x40000000, size: 104400 bytes
section: .rodata, addr: 0x400197d0, size: 15616 bytes
section: .data, addr: 0x4001d4d0, size: 1176 bytes
read 1006 symbols
Initializing and starting from 0x40000000
Hello, this is Rust!
PANIC: PanicInfo { payload: Any { .. }, message: Some(I am a panic), location: Location { file: "src/main.rs", line: 33, col: 5 }, can_unwind: true }
Program exited normally on CPU 0.
```
> Does the target support running the Rust testsuite?
I don't think so, the testsuite requires `libstd` IIRC.
## Cross-compilation toolchains and C code
> Does the target support C code?
Yes.
> If so, what toolchain target should users use to build compatible C code? (This may match the target triple, or it may be a toolchain for a different target triple, potentially with specific options or caveats.)
I suggest [BCC2] from Gaisler. It comes in both GCC and Clang variants.
alignment of `byval` on x86 in the process.
Commit 88e4d2c291 from five years ago removed
support for alignment on indirectly-passed arguments because of problems with
the `i686-pc-windows-msvc` target. Unfortunately, the `memcpy` optimizations I
recently added to LLVM 16 depend on this to forward `memcpy`s. This commit
attempts to fix the problems with `byval` parameters on that target and now
correctly adds the `align` attribute.
The problem is summarized in [this comment] by @eddyb. Briefly, 32-bit x86 has
special alignment rules for `byval` parameters: for the most part, their
alignment is forced to 4. This is not well-documented anywhere but in the Clang
source. I looked at the logic in Clang `TargetInfo.cpp` and tried to replicate
it here. The relevant methods in that file are
`X86_32ABIInfo::getIndirectResult()` and
`X86_32ABIInfo::getTypeStackAlignInBytes()`. The `align` parameter attribute
for `byval` parameters in LLVM must match the platform ABI, or miscompilations
will occur. Note that this doesn't use the approach suggested by eddyb, because
I felt it was overkill to store the alignment in `on_stack` when special
handling is really only needed for 32-bit x86.
As a side effect, this should fix#80127, because it will make the `align`
parameter attribute for `byval` parameters match the platform ABI on LLVM
x86-64.
[this comment]: https://github.com/rust-lang/rust/pull/80822#issuecomment-829985417
linker flavors
- only the stable values for `-Clink-self-contained` can be used on stable until we
have more feedback on the interface
- `-Zunstable-options` is required to use unstable linker flavors
Fix unset e_flags in ELF files generated for AVR targets
Closes#106576
~~Sort-of blocked by gimli-rs/object#500~~ (merged)
I'm not sure whether the list of AVR CPU names is okay here. Maybe it could be moved out-of-line to improve the readability of the function.
loongarch64-unknown-none*: Set default relocation model to static
This PR sets the default relocation model to `static` for `loongarch64-unknown-none*` targets. This change aims to streamline the development of the bare-metal project by removing the need for the executable program loader to implement relocation.
Force all native libraries to be statically linked when linking a static binary
Previously, `#[link]` without an explicit `kind = "static"` would confuse the linker and end up producing a dynamically linked library because of the `-Bdynamic` flag. However this binary would not work correctly anyways since it was linked with startup code for a static binary.
This PR solves this by forcing all native libraries to be statically linked when the output is a static binary that cannot link to dynamic libraries anyways.
Fixes#108878Fixes#102993
Improved std support for ps vita target
Fixed a couple of things in std support for ps vita via Vita SDK newlib oss implementation:
- Added missing hardware features to target spec
- Compile in thumb by default (newlib is also compiled in thumb)
- Fixed fs calls. Vita newlib has a not-very-posix dirent. Also vita does not expose inodes, it's stubbed as 0 in stat, and I'm stubbing it here for dirent (because vita newlibs's dirent doesn't even have that field)
- Enabled signal handlers for panic unwinding
- Dropped static link requirement from the platform support md. Also, rearranged sections to better stick with the template.
Support 128-bit atomics on all x86_64 Apple targets
On x86_64, we currently set `max_atomic_width` to 128 only on macOS.
ad8304a0d5/compiler/rustc_target/src/spec/x86_64_apple_darwin.rs (L8)
However, other x86_64 Apple targets (iOS, tvOS, and watchOS) are also core2+ and support cmpxchg16b.
ad8304a0d5/compiler/rustc_target/src/spec/apple_base.rs (L71-L76)
```console
# Script to get targets that support cmpxchg16b by default:
$ (for target in $(rustc --print target-list); do [[ $target == "x86_64"* ]] && rustc --print cfg --target "$target" | grep -q cmpxchg16b && echo "$target"; done)
x86_64-apple-darwin
x86_64-apple-ios
x86_64-apple-ios-macabi
x86_64-apple-tvos
x86_64-apple-watchos-sim
x86_64h-apple-darwin
```
r? `@Amanieu`
linker: Report linker flavors incompatible with the current target
The linker flavor is checked for target compatibility even if linker is never used (e.g. we are producing a rlib).
If it causes trouble, we can move the check to `link.rs` so it will run if the linker (flavor) is actually used.
And also feature gate explicitly specifying linker flavors for tier 3 targets.
The next step is supporting all the internal linker flavors in user-visible interfaces (command line and json).
Go through an intermediate pair of `cc`and `lld` hints instead of mapping CLI options to `LinkerFlavor` directly, and use the target's default linker flavor as a reference.
Adds support for LLVM [SafeStack] which provides backward edge control
flow protection by separating the stack into two parts: data which is
only accessed in provable safe ways is allocated on the normal stack
(the "safe stack") and all other data is placed in a separate allocation
(the "unsafe stack").
SafeStack support is enabled by passing `-Zsanitizer=safestack`.
[SafeStack]: https://clang.llvm.org/docs/SafeStack.html
Fix linking Mac Catalyst by including LC_BUILD_VERSION in object files
Hello. My first rustc PR!
Issue #106021 prevents Rust code from being linked into Mac Catalyst applications. Apple's LD has started requiring object files to contain version information about the platform they were built for, such as:
* the "deployment target" (minimum supported OS version),
* the SDK version
* the type of the platform (macOS/iOS/catalyst/tvOS/watchOS all have a different number).
This is currently only enforced when building for Mac Catalyst.
Rust uses the `object` crate which added support for including this information starting with `0.31.0`. ~~I upgraded it along with `thorin-dwp` so that everything depends on 0.31.
Apparently 0.31 [pulls in](https://github.com/gimli-rs/object/issues/463) `ruzstd` due to a [new ELF standard](https://maskray.me/blog/2022-09-09-zstd-compressed-debug-sections) because its `compression` feature is enabled by thorin. If you find this objectionable, let me know what the best way to avoid pulling in those dependencies might be.~~
**(`object` upgraded in https://github.com/rust-lang/rust/pull/111413)**
I then added two commits:
* The first one adds very basic, hard-coded support for calling `set_macho_build_version` for `-macabi` (Catalyst) targets, where it claims deployment target of Catalyst 14.0 and SDK of 16.2.
* The second weaves the versioning through `rust_target::spec::TargetOptions`, so that we can stick to specifying all target-related info in one place.
Kudos to ``@ara4n`` for writing [this gist](https://gist.github.com/ara4n/320a53ea768aba51afad4c9ed2168536).
Rollup of 4 pull requests
Successful merges:
- #95198 (Add slice::{split_,}{first,last}_chunk{,_mut})
- #109899 (Use apple-m1 as target CPU for aarch64-apple-darwin.)
- #111624 (Emit diagnostic for privately uninhabited uncovered witnesses.)
- #111875 (Don't leak the function that is called on drop)
r? `@ghost`
`@rustbot` modify labels: rollup
Use apple-m1 as target CPU for aarch64-apple-darwin.
This updates the target CPU for the `aarch64-apple-darwin` target to `apple-m1`, which is the first generation of CPUs with this target anyway.
This wasn't able to be done before because of the minimum supported version of LLVM being 12, now that it was updated to 13 (in fact we are already at 14), this is available.
See previous update: https://github.com/rust-lang/rust/pull/90478.
See LLVM update: https://github.com/rust-lang/rust/pull/100460.
CFI: Fix SIGILL reached via trait objects
Fix#106547 by transforming the concrete self into a reference to a trait object before emitting type metadata identifiers for trait methods.
STD support for PSVita
This PR adds std support for `armv7-sony-vita-newlibeabihf` target.
The work here is fairly similar to #95897, just for a different target platform.
This depends on the following pull requests:
rust-lang/backtrace-rs#523rust-lang/libc#3209
Update max_atomic_width of armv7r and armv7_sony_vita targets to 64.
All armv7a and armv7r implementations support `ldrexd`/`strexd`, only armv7m does not.
