It's possible to build no_std programs with this compiler.
> 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.)
Tim Newsome (@tnewsome-lynx) will be the designated developer for
x86_64-lynx-lynxos178 support.
> 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 believe the target is named appropriately.
> 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.
The target name is not confusing.
> If possible, use only letters, numbers, dashes and underscores for the name.
Periods (.) are known to cause issues in Cargo.
Done.
> 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).
All this new code is licensed under the Apache-2.0 license.
> 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.
Done.
> 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.
I think we're in the clear here. We do link against some static libraries that
are proprietary (like libm and libc), but those are not used to generate code.
E.g. the VxWorks target requires `wr-c++` to be installed, which is not
publically available.
> "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.
Our intention is to allow anyone with access to LynxOS CDK to use Rust for it.
> 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.
No problem.
> 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.
With this first PR, only core is supported. I am working on support for the std
library and intend to submit that once all the tests are passing.
> 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.
This is documented in `src/doc/rustc/src/platform-support/lynxos_178.md`.
> 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.
As far as I know this change does not affect any other targets.
> Tier 3 targets must be able to produce assembly using at least one of rustc's
supported backends from any host target. (Having support in a fork of the
backend is not sufficient, it must be upstream.)
Many targets produce assembly for x86_64 so that also works for LynxOS-178.
Make x86 QNX target name consistent with other Rust targets
Rename target to be consistent with other Rust targets: Use `i686` instead of `i586`
See also
- #136495
- #109173
CC: `@jonathanpallant` `@japaric` `@gh-tr` `@samkearney`
This commit removes the `avr-unknown-gnu-atmega328` target and replaces
it with a more generic `avr-none` variant that must be specialized with
the `-C target-cpu` flag (e.g. `-C target-cpu=atmega328p`).
add m68k-unknown-none-elf target
r? `@workingjubilee`
The existing `m68k-unknown-linux-gnu` target builds `std` by default, requires atomics, and has a base cpu with an fpu. A smaller/more embedded target is desirable both to have a baseline target for the ISA, as well to make debugging easier for working on the llvm backend. Currently this target is using the `M68010` as the minimum CPU due, but as missing features are merged into the `M68k` llvm backend I am hoping to lower this further.
I have been able to build very small crates using a toolchain built against this target (together with a later version of `object`) using the configuration described in the target platform-support documentation, although getting anything of substantial complexity to build quickly hits errors in the llvm backend
Target: Add mips mti baremetal support
Do the same thing as gcc, which use the vendor `mti` to mark the toolchain as MIPS32r2 default.
We support both big endian and little endian flavor:
mips-mti-none-elf
mipsel-mti-none-elf
In llvm/llvm-project@7b23f413d1 , `.text`
started being suppressed from LLVM assembly in cases where it wasn't
strictly necessary. Currently, the sample functions in these two tests
are frequently decided to be IR-only functions, resulting in no code
generation, so LLVM drops the `.text` directive.
Adding `#[no_mangle]` forces these tests back to their original intent -
assembly code is generated, and so a `.text` directive is generated as
well.
Do the same thing as gcc, which use the vendor `mti` to mark
the toolchain as MIPS32r2 default.
We support both big endian and little endian flavor:
mips-mti-none-elf
mipsel-mti-none-elf
This commit is the final step in the journey of renaming the historical
`wasm32-wasi` target in the Rust compiler to `wasm32-wasip1`. Various
steps in this journey so far have been:
* 2023-04-03: rust-lang/compiler-team#607 - initial proposal for this rename
* 2024-11-27: rust-lang/compiler-team#695 - amended schedule/procedure for rename
* 2024-01-29: rust-lang/rust#120468 - initial introduction of `wasm32-wasip1`
* 2024-06-18: rust-lang/rust#126662 - warn on usage of `wasm32-wasi`
* 2024-11-08: this PR - remove the `wasm32-wasi` target
The full transition schedule is in [this comment][comment] and is
summarized with:
* 2024-05-02: Rust 1.78 released with `wasm32-wasip1` target
* 2024-09-05: Rust 1.81 released warning on usage of `wasm32-wasi`
* 2025-01-09: Rust 1.84 to be released without the `wasm32-wasi` target
This means that support on stable for the replacement target of
`wasm32-wasip1` has currently been available for 6 months. Users have
already seen warnings on stable for 2 months about usage of
`wasm32-wasi` and stable users have another 2 months of warnings before
the target is removed from stable.
This commit is intended to be the final step in this transition so the
source tree should no longer mention `wasm32-wasi` except in historical
reference to the older name of the `wasm32-wasip1` target.
[comment]: https://github.com/rust-lang/rust/pull/120468#issuecomment-1977878747
Add x86_64-unknown-trusty as tier 3 target
This PR adds a third target for the Trusty platform, `x86_64-unknown-trusty`.
Please let me know if an MCP is required. https://github.com/rust-lang/compiler-team/issues/582 was made when adding the first two targets, I can make another one for the new target as well if needed.
# Target Tier Policy Acknowledgements
> 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.)
- Nicole LeGare (```@randomPoison)```
- Andrei Homescu (```@ahomescu)```
- Chris Wailes (chriswailes@google.com)
- As a fallback trusty-dev-team@google.com can be contacted
Note that this does not reflect the maintainers currently listed in [`trusty.md`](c52c23b6f4/src/doc/rustc/src/platform-support/trusty.md). #130452 is currently open to update the list of maintainers in the documentation.
> 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.
The new target `x86_64-unknown-trusty` follows the existing naming convention for similar targets.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
👍
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
There are no known legal issues or license incompatibilities.
> 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.
👍
> 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 PR only adds the target. `std` support is being worked on and will be added in a future PR.
> 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.
👍
> 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.
👍
> 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.
👍
> Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target. (Having support in a fork of the backend is not sufficient, it must be upstream.)
👍
Add powerpc-unknown-linux-muslspe compile target
This is almost identical to already existing targets:
- powerpc_unknown_linux_musl.rs
- powerpc_unknown_linux_gnuspe.rs
It has support for PowerPC SPE (muslspe), which
can be used with GCC version up to 8. It is useful for Freescale or IBM cores like e500.
This was verified to be working with OpenWrt build system for CZ.NIC's Turris 1.x routers, which are using Freescale P2020, e500v2, so add it as a Tier 3 target.
Follow-up of https://github.com/rust-lang/rust/pull/100860
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. It is scalable from 8-bit to 64-bit microcontroller environments. The primary governing standards in NuttX are POSIX and ANSI standards.
NuttX adopts additional standard APIs from Unix and other common RTOSs, such as VxWorks. These APIs are used for functionality not available under the POSIX and ANSI standards. However, some APIs, like fork(), are not appropriate for deeply-embedded environments and are not implemented in NuttX.
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
I'll be adding libstd support for NuttX in the future, but for now I'll just add the 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 will be the target maintainer for this target on matters that pertain to the NuttX part of the triple.
For matters pertaining to the riscv or arm part of the triple, there should be no difference from all other targets. If there are issues, I will address issues regarding the target.
> 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 is a new supported OS, so I have taken the origin target like `riscv32imac-unknown-none-elf` or `thumbv7m-none-eabi`
and changed the `os` section to `nuttx`.
> 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 feel that the target name does not introduce any ambiguity.
> 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 only unusual requirement for building the compiler-builtins crate is a standard RISC-V or ARM C compiler supported by cc-rs, and using this target does not require any additional software beyond what is shipped by rustup.
> The target must not introduce license incompatibilities.
All of the additional code will use Apache-2.0.
> Anything added to the Rust repository must be under the standard Rust
> license (`MIT OR Apache-2.0`).
Agreed, and there is no problem here.
> 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.
No new dependencies are added.
> 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.
Linking is performed by rust-lld
> "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 terms. NuttX is distributed under the Apache 2.0 license.
> 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.
> 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, but libstd is not supported now,
I'll implement it later.
> 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.
> Tier 3 targets must be able to produce assembly using at least one of
> rustc's supported backends from any host target. (Having support in a fork
> of the backend is not sufficient, it must be upstream.)
Yes, it use standard RISCV or ARM backend to generate assembly.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
This is almost identical to already existing targets:
- powerpc_unknown_linux_musl.rs
- powerpc_unknown_linux_gnuspe.rs
It has support for PowerPC SPE (muslspe), which
can be used with GCC version up to 8. It is useful for Freescale or IBM
cores like e500.
This was verified to be working with OpenWrt build system for CZ.NIC's
Turris 1.x routers, which are using Freescale P2020, e500v2, so add it as
a Tier 3 target.
Add std Xtensa targets support
Adds std Xtensa targets. This enables using Rust on ESP32, ESP32-S2 and ESP32-S3 chips.
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.)
`@MabezDev,` `@ivmarkov` and I (`@SergioGasquez)` will maintain the targets.
> 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.
The target triple is consistent with other targets.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to
maintain ecosystem compatibility. For example, if the name of the target makes people extremely
likely to form incorrect beliefs about what it targets, the name should be changed or augmented to
disambiguate it.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known
to cause issues in Cargo.
We follow the same naming convention as other 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 does not introduce any legal issues.
> The target must not introduce license incompatibilities.
There are no license incompatibilities
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Everything added is under that licenses
> 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.
Requirements are not changed for any other target.
> 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.
The linker used by the targets is the GCC linker from the GCC toolchain cross-compiled for Xtensa.
GNU GPL.
> "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 such terms exist for this target
> 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.
The targets implement libStd almost in its entirety, except for the missing support for process, as
this is a bare metal platform. The process `sys\unix` module is currently stubbed to return "not
implemented" errors.
> 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.
Here is how to build for the target https://docs.esp-rs.org/book/installation/riscv-and-xtensa.html
and it also covers how to run binaries on the target.
> 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.
No other targets should be affected
> Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends
from any host target.
It can produce assembly, but it requires a custom LLVM with Xtensa support
(https://github.com/espressif/llvm-project/). The patches are trying to be upstreamed
(https://github.com/espressif/llvm-project/issues/4)
Add aarch64-apple-visionos and aarch64-apple-visionos-sim tier 3 targets
Introduces `aarch64-apple-visionos` and `aarch64-apple-visionos-sim` as tier 3 targets. This allows native development for the Apple Vision Pro's visionOS platform.
This work has been tracked in https://github.com/rust-lang/compiler-team/issues/642. There is a corresponding `libc` change https://github.com/rust-lang/libc/pull/3568 that is not required for merge.
Ideally we would be able to incorporate [this change](https://github.com/gimli-rs/object/pull/626) to the `object` crate, but the author has stated that a release will not be cut for quite a while. Therefore, the two locations that would reference the xrOS constant from `object` are hardcoded to their MachO values of 11 and 12, accompanied by TODOs to mark the code as needing change. I am open to suggestions on what to do here to get this checked in.
# 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-visionos.md](e88379034a/src/doc/rustc/src/platform-support/apple-visionos.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` which is matches the iOS Apple Silicon simulator (`aarch64-apple-ios-sim`) and other Apple 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 besubject 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 mirrors the standard library for watchOS and iOS, with minor divergences.
> 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.
Documentation is provided in [src/doc/rustc/src/platform-support/apple-visionos.md](e88379034a/src/doc/rustc/src/platform-support/apple-visionos.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.
