Support for ARMv8.3+ targets #73628
Labels
A-LLVM
Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues.
C-feature-request
Category: A feature request, i.e: not implemented / a PR.
C-tracking-issue
Category: An issue tracking the progress of sth. like the implementation of an RFC
O-AArch64
Armv8-A or later processors in AArch64 mode
O-apple
Operating system: Apple (macOS, iOS, tvOS, visionOS, watchOS)
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
Comments
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In addition, arm64e support important due to the upcoming Mac desktops running Bionic processors (such as an A12Z). |
jonas-schievink
added
C-feature-request
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Upstream LLVM supports armv8.3, and most likely the Rust LLVM as well. |
Weren't you working on building a custom LLVM since upstream doesn't support this yet? The link just goes to an RFC thread on the mailing list with no replies. |
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@jonas-schievink I was poorly attempting to jury-rig apple/llvm-project onto rustc. In short, I got arm64e and armv8.3 mixed up. A quick grep and dig through rust-project/llvm reveals that it has the code for ARMv8.3 and Pointer Authentication support. |
Absolucy
changed the title
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ARMv8.5 support would also be good, considering that there's a high likelihood than ARM Macs will run on ARMv8.5. |
jonas-schievink
added
the
A-LLVM
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This isn't upstreamed, my bad. |
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Note that the macOS 11 SDK has both arm64-macos and arm64e-macos targets, although the arm64 variants don't have an uuid in the system library TBD files. |
That's not merged in LLVM upstream. |
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@glandium my bad. |
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I'm interested in this as well because of Apple Silicon (i.e arm64 on macOS) Going forward it will be mandated by Apple that executable released (at least for the App Store) supports both There is a command line tool called |
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We (Embark) are interested in it as well, should we track having a Darwin Mac on ARM target in this issue or file an additional one specifically for it (with some overlap with this)? |
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We'd need someone with a Developer Transition Kit to truly test any sort of support for this. |
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The Edit: sorry, this was a typo. I meant to write |
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@19h |
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@Luxxxxy It's unfortunate that both arm64 and aarch64 refer to the same ISA, whereas the former was the result of proprietary work by Apple that only was open-sourced after other vendors published their work on the latter. Aarch64 is an alias for the ARMv8-A ISA, and it would be confusing to have arm64e coexist with aarch64. But given that arm64e actually references a proprietary extension of the ARMv8-A ISA (it is actually an ABI), it might be reasonable to have it named in a way that clearly separates it from the other. |
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@Luxxxxy If one had such a device, would you be interested in testing something on it? |
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I have an arm64e phone (iPhone 11, iOS 13.5) I'd be glad to test something on it, I've been using it to get rustc/cargo working on iOS. |
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I am currently adding PAC/arm64e to a fork using Apple's LLVM. Hopefully some of my work can be reused whenever PAC/arm64e support is upstreamed into LLVM. |
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that's work on jailbreak only? |
That's how I'm testing it. However, most likely, this will also work on Apple Silicon (ARM) macs. Not sure if iOS lets you submit arm64e slice apps to the app store, though. |
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@hjmallon Hello, The arm64e ABI is currently not considered as final. To run arm64e binaries on macOS on Apple Silicon, add the -arm64e_preview_abi argument to boot-args. Arm 64-bit macOS supports arm64 binaries, and that's the only supported configuration. Currently, arm64e is only for bundled in the OS applications and libraries, as you can load arm64e binaries in an arm64 process. |
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In some cases, the
It seems that Apple just simply disables PAC on arm64 process to accomplish 2 and 3. However, case 1 can still not be covered if there is no arm64e target. I am not sure whether there is another case of ”cross arch“ interaction like case 1. |
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I believe that we may see proper PAC support soon, with #88354 |
workingjubilee
removed
the
O-Arm
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Any news on this? |
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Any progress on this issue? |
compiler-errors
added a commit
to compiler-errors/rust
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this issue
Nov 20, 2023
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,](rust-lang#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. rust-lang#73628
bors
added a commit
to rust-lang-ci/rust
that referenced
this issue
Nov 20, 2023
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,](rust-lang#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. rust-lang#73628
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What's missing after #115526 to have |
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@glandium It needs to be promoted to tier 2 AFAIK |
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I sent a MCP to do the promotion for arm64-darwin. |
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For what it's worth, LLVM doesn't support CPU_SUBTYPE_PTRAUTH_ABI yet, which is required by Xcode's linker to link arm64e code. |
This was referenced Sep 7, 2024
GuillaumeGomez
added a commit
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this issue
Sep 20, 2024
Add arm64e-apple-tvos target This introduces * `arm64e-apple-tvos` ## 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 a 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 `arm64e-apple-tvos` target names like `arm64e-apple-ios`, `arm64e-apple-darwin`. So, **I have chosen this name 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. Understood. rust-lang#121663 rust-lang#73628
rust-timer
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Sep 20, 2024
Rollup merge of rust-lang#130614 - arttet:arm64e-apple-tvos, r=bjorn3 Add arm64e-apple-tvos target This introduces * `arm64e-apple-tvos` ## 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 a 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 `arm64e-apple-tvos` target names like `arm64e-apple-ios`, `arm64e-apple-darwin`. So, **I have chosen this name 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. Understood. rust-lang#121663 rust-lang#73628
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Summary:
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I'll add a few more things:
And link a few things:
@rustbot label O-apple |
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Currently, a blocker in a project of mine - Crabapple - is the lack of native arm64e support in Rust.
The
aarch64-apple-iostarget only emits arm64 (ARMv8) code, which will not work within an arm64e (ARMv8.3+) environment due to it's lack of awareness of Pointer Authentication, leading to segfaults when trying to access a signed pointer.It is currently possible to work around this, by using a backtrace=false rustc, compiling with
--emit=llvm-ir -Clto, and running the resulting IR through an arm64e-aware LLVM (such as apple/llvm-project). Pointer authentication may be worked around by linking to an FFI function that runs ptrauth_strip.This may require LLVM changes if done, and quite possibly a new target (
arm64e-apple-ios,aarch64-apple-ios-armv83, etc)The text was updated successfully, but these errors were encountered: