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.
Remove the unstable `extern "wasm"` ABI (`wasm_abi` feature tracked
in #83788).
As discussed in https://github.com/rust-lang/rust/pull/127513#issuecomment-2220410679
and following, this ABI is a failed experiment that did not end
up being used for anything. Keeping support for this ABI in LLVM 19
would require us to switch wasm targets to the `experimental-mv`
ABI, which we do not want to do.
It should be noted that `Abi::Wasm` was internally used for two
things: The `-Z wasm-c-abi=legacy` ABI that is still used by
default on some wasm targets, and the `extern "wasm"` ABI. Despite
both being `Abi::Wasm` internally, they were not the same. An
explicit `extern "wasm"` additionally enabled the `+multivalue`
feature.
I've opted to remove `Abi::Wasm` in this patch entirely, instead
of keeping it as an ABI with only internal usage. Both
`-Z wasm-c-abi` variants are now treated as part of the normal
C ABI, just with different different treatment in
adjust_for_foreign_abi.
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 no_std Xtensa targets support
Adds no_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` 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 target already implements core.
> 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)
Relax restrictions on multiple sanitizers
Most combinations of LLVM sanitizers are legal-enough to enable simultaneously. This change will allow simultaneously enabling ASAN and shadow call stacks on supported platforms.
I used this python script to generate the mutually-exclusive sanitizer combinations:
```python
#!/usr/bin/python3
import subprocess
flags = [
["-fsanitize=address"],
["-fsanitize=leak"],
["-fsanitize=memory"],
["-fsanitize=thread"],
["-fsanitize=hwaddress"],
["-fsanitize=cfi", "-flto", "-fvisibility=hidden"],
["-fsanitize=memtag", "--target=aarch64-linux-android", "-march=armv8a+memtag"],
["-fsanitize=shadow-call-stack"],
["-fsanitize=kcfi", "-flto", "-fvisibility=hidden"],
["-fsanitize=kernel-address"],
["-fsanitize=safe-stack"],
["-fsanitize=dataflow"],
]
for i in range(len(flags)):
for j in range(i):
command = ["clang++"] + flags[i] + flags[j] + ["-o", "main.o", "-c", "main.cpp"]
completed = subprocess.run(command, stderr=subprocess.DEVNULL)
if completed.returncode != 0:
first = flags[i][0][11:].replace('-', '').upper()
second = flags[j][0][11:].replace('-', '').upper()
print(f"(SanitizerSet::{first}, SanitizerSet::{second}),")
```
the `rust.lld` config enables rustc's `CFG_USE_SELF_CONTAINED_LINKER` env var, and we:
- set the linker-flavor to use lld
- enable the self-contained linker
this makes the target use the rust-lld linker by default
Most combinations of LLVM sanitizers are legal-enough to enable
simultaneously. This change will allow simultaneously enabling ASAN and
shadow call stacks on supported platforms.
Change `SIGPIPE` ui from `#[unix_sigpipe = "..."]` to `-Zon-broken-pipe=...`
In the stabilization [attempt](https://github.com/rust-lang/rust/pull/120832) of `#[unix_sigpipe = "sig_dfl"]`, a concern was [raised ](https://github.com/rust-lang/rust/pull/120832#issuecomment-2007394609) related to using a language attribute for the feature: Long term, we want `fn lang_start()` to be definable by any crate, not just libstd. Having a special language attribute in that case becomes awkward.
So as a first step towards the next stabilization attempt, this PR changes the `#[unix_sigpipe = "..."]` attribute to a compiler flag `-Zon-broken-pipe=...` to remove that concern, since now the language is not "contaminated" by this feature.
Another point was [also raised](https://github.com/rust-lang/rust/pull/120832#issuecomment-1987023484), namely that the ui should not leak **how** it does things, but rather what the **end effect** is. The new flag uses the proposed naming. This is of course something that can be iterated on further before stabilization.
Tracking issue: https://github.com/rust-lang/rust/issues/97889
In the stabilization attempt of `#[unix_sigpipe = "sig_dfl"]`, a concern
was raised related to using a language attribute for the feature: Long
term, we want `fn lang_start()` to be definable by any crate, not just
libstd. Having a special language attribute in that case becomes
awkward.
So as a first step towards towards the next stabilization attempt, this
PR changes the `#[unix_sigpipe = "..."]` attribute to a compiler flag
`-Zon-broken-pipe=...` to remove that concern, since now the language
is not "contaminated" by this feature.
Another point was also raised, namely that the ui should not leak
**how** it does things, but rather what the **end effect** is. The new
flag uses the proposed naming. This is of course something that can be
iterated on further before stabilization.
Introduce perma-unstable `wasm-c-abi` flag
Now that `wasm-bindgen` v0.2.88 supports the spec-compliant C ABI, the idea is to switch to that in a future version of Rust. In the meantime it would be good to let people test and play around with it.
This PR introduces a new perma-unstable `-Zwasm-c-abi` compiler flag, which switches to the new spec-compliant C ABI when targeting `wasm32-unknown-unknown`.
Alternatively, we could also stabilize this and then deprecate it when we switch. I will leave this to the Rust maintainers to decide.
This is a companion PR to #117918, but they could be merged independently.
MCP: https://github.com/rust-lang/compiler-team/issues/703
Tracking issue: https://github.com/rust-lang/rust/issues/122532
While they're isomorphic, we can flip the lld component where
applicable, so that downstream doesn't have to check both the flavor and
the linker features.
They are a flexible complementary mechanism to linker flavors,
that also avoid the combinatorial explosion of mapping linking features
to actual linker flavors.
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.
Remove `target_override`
Because the "target can override the backend" and "backend can override the target" situation is a mess. Details in the individual commits.
r? `@WaffleLapkin`
Backend and target selection is a mess: the target can override the
backend (via `Target::default_codegen_backend`), *and* the backend can
override the target (via `CodegenBackend::target_override`).
The code that handles this is ugly. It calls `build_target_config`
twice, once before getting the backend and once again afterward. It also
must check that both overrides aren't triggering at the same time.
This commit removes the latter override. It's used in rust-gpu but
@eddyb said via Zulip that removing it would be ok. This simplifies the
code greatly, and will allow some nice follow-up refactorings.
Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`
This commit renames the current `wasm32-wasi-preview1-threads` target to `wasm32-wasip1-threads`. The need for this rename is a bit unfortunate as the previous name was chosen in an attempt to be future-compatible with other WASI targets. Originally this target was proposed to be `wasm32-wasi-threads`, and that's what was originally implemented in wasi-sdk as well. After discussion though and with the plans for the upcoming component-model target (now named `wasm32-wasip2`) the "preview1" naming was chosen for the threads-based target. The WASI subgroup later decided that it was time to drop the "preview" terminology and recommends "pX" instead, hence previous PRs to add `wasm32-wasip2` and rename `wasm32-wasi` to `wasm32-wasip1`.
So, with all that history, the "proper name" for this target is different than its current name, so one way or another a rename is required. This PR proposes renaming this target cold-turkey, unlike `wasm32-wasi` which is having a long transition period to change its name. The threads-based target is predicted to see only a fraction of the traffic of `wasm32-wasi` due to the unstable nature of the WASI threads proposal itself.
While I was here I updated the in-tree documentation in the target spec file itself as most of the documentation was copied from the original WASI target and wasn't as applicable to this target.
Also, as an aside, I can at least try to apologize for all the naming confusion here, but this is hopefully the last WASI-related rename.
This commit renames the current `wasm32-wasi-preview1-threads` target to
`wasm32-wasip1-threads`. The need for this rename is a bit unfortunate
as the previous name was chosen in an attempt to be future-compatible
with other WASI targets. Originally this target was proposed to be
`wasm32-wasi-threads`, and that's what was originally implemented in
wasi-sdk as well. After discussion though and with the plans for the
upcoming component-model target (now named `wasm32-wasip2`) the
"preview1" naming was chosen for the threads-based target. The WASI
subgroup later decided that it was time to drop the "preview"
terminology and recommends "pX" instead, hence previous PRs to add
`wasm32-wasip2` and rename `wasm32-wasi` to `wasm32-wasip1`.
So, with all that history, the "proper name" for this target is
different than its current name, so one way or another a rename is
required. This PR proposes renaming this target cold-turkey, unlike
`wasm32-wasi` which is having a long transition period to change its
name. The threads-based target is predicted to see only a fraction of
the traffic of `wasm32-wasi` due to the unstable nature of the WASI
threads proposal itself.
While I was here I updated the in-tree documentation in the target spec
file itself as most of the documentation was copied from the original
WASI target and wasn't as applicable to this target.
Also, as an aside, I can at least try to apologize for all the naming
confusion here, but this is hopefully the last WASI-related rename.
LLVM Bitcode Linker: A self contained linker for nvptx and other targets
This PR introduces a new linker named `llvm-bitcode-linker`. It is a `self-contained` linker that can be used to link programs in `llbc` before optimizing and compiling to native code. It will first be used internally in the Rust compiler to enable tests for the `nvptx64-nvidia-cuda` target as the original `rust-ptx-linker` is deprecated. It will then be provided to users of the `nvptx64-nvidia-cuda` target with the purpose of linking ptx. More targets than nvptx will also be supported eventually.
The PR introduces a new unstable `LinkerFlavor` for the compiler. The compiler will also not be shipped with rustc but most likely instead be shipped in it's own unstable component (a follow up PR will be opened for this). This means that merging this PR should not add any stability guarantees.
When more details of `self-contained` is implemented it will only be possible to use the linker when `-Clink-self-contained=+linker` is passed.
<details>
<summary>Original Description</summary>
**When this PR was created it was focused a bit differently. The original text is preserved here in case there's some interests in it**
I have experimenting with approaches to replace the ptx-linker and enable the nvptx target tests again. I think it's time to get some feedback on the approach.
### The problem
The only useful linker for the nvptx target is [this crate](https://github.com/denzp/rust-ptx-linker). Since this linker performs linking on llvm bitcode it needs to track the llvm version of rustc and use the same format. It has not been maintained for 3+ years and must be considered abandoned. Over the years rust have upgraded LLVM while the linker has been left to bitrot. It is no longer in a usable state.
Due to the difficulty of keeping the ptx-linker up to date outside of tree the nvptx tests was [disabled a long time ago](f8f9a2869c). It was [previously discussed](https://github.com/rust-lang/rust/pull/96842#issuecomment-1146470177) if adding the ptx-linker to the rust repo would be a possibility. My efforts in doing this stopped at getting an answered if the license would prohibit it from inclusion in the [Rust repo](https://github.com/rust-lang/rust/pull/96842#issuecomment-1148397554). I therefore concluded that a re-write would be necessary.
### The possible solution presented here
The llvm tools know perfectly well how to link and optimize llvm bitcode. Each of them only perform a single task, and are therefore a bit cumbersome to call with the current linker approach rustc takes.
This PR adds a simple tool (current name `embedded-linker`) which can link self contained (often embedded) programs in llvm bitcode before compiling to the target format. Optimization will also be performed if lto is enabled. The rust compiler will make a single invocation to this tool, while the tool will orchestrate the many calls to the llvm tools.
### The questions
- Is having control over the nvptx linking and therefore also tests worth it to add such tool? or should the tool live outside the rust repo?
- Is the approach of calling llvm tools acceptable? Or would we want to keep the ptx-linker approach of using the llvm library? The tools seems to provide more simplicity and stability, but more intermediate files are being written. Perhaps there also are some performance penalty for the calling tools approach.
- What is the process for adding such tool? MCP?
- Does adding `llvm-link` to the llvm-tool component require any process?
- Does it require some sort of FCP to remove ptx-linker as the default linker for ptx? Or is it sufficient that using the upstream ptx-linker is broken in its current state. it is possible to use a somewhat patched version of ptx-linker.
</details>
This adds four pieces of metadata to every target:
- description
- tier
- host tools
- std
This information is currently scattered across target docs and both
- not machine readable, making validation harder
- sometimes subtly encoding by the table it's in, causing mistakes and
making it harder to review changes to the properties
By putting it in the compiler, we improve this. Later, we will use this
canonical information to generate target documentation from it.
Add the new description field to Target::to_json, and add descriptions for some MSVC targets
The original PR to add a `description` field to `Target` (<https://github.com/rust-lang/rust/pull/121905>) didn't add the field to `Target::to_json`, which meant that the `check_consistency` testwould fail if you tried to set a description as it wouldn't survive round-tripping via JSON: 2237005253 (step):27:4967
This change adds the field to `Target::to_json`, and sets some descriptions to verify that it works correctly.
Introduces the `arm64ec-pc-windows-msvc` target for building Arm64EC ("Emulation Compatible") binaries for Windows.
For more information about Arm64EC see <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
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 maintainer for this 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.
Target uses the `arm64ec` architecture to match LLVM and MSVC, and the `-pc-windows-msvc` suffix to indicate that it targets Windows via the MSVC environment.
> 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.
Target name exactly specifies the type of code that will be produced.
> 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.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> 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.
> 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.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> 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 the 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.
Both `core` and `alloc` are supported.
Support for `std` dependends on making changes to the standard library, `stdarch` and `backtrace` which cannot be done yet as the bootstrapping compiler raises a warning ("unexpected `cfg` condition value") for `target_arch = "arm64ec"`.
> 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/arm64ec-pc-windows-msvc.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.
> 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.
This is the short description (`64-bit MinGW (Windows 7+)`) including
the platform requirements.
The reason for doing it like this is that this PR will be quite prone to
conflicts whenever targets get added, so it should be as simple as
possible to get it merged. Future PRs which migrate targets are scoped
to groups of targets, so they will not conflict as they can just touch
these.
This moves some of the information from the rustc book into the
compiler.
It cannot be queried yet, that is future work. It is also future work to
fill out all the descriptions, which will coincide with the work of
moving over existing target docs to the new format.
Add a new `wasm32-wasip1` target to rustc
This commit adds a new target called `wasm32-wasip1` to rustc. This new target is explained in these two MCPs:
* https://github.com/rust-lang/compiler-team/issues/607
* https://github.com/rust-lang/compiler-team/issues/695
In short, the previous `wasm32-wasi` target is going to be renamed to `wasm32-wasip1` to better live alongside the [new `wasm32-wasip2` target](https://github.com/rust-lang/rust/pull/119616). This new target is added alongside the `wasm32-wasi` target and has the exact same definition as the previous target. This PR is effectively a rename of `wasm32-wasi` to `wasm32-wasip1`. Note, however, that as explained in rust-lang/compiler-team#695 the previous `wasm32-wasi` target is not being removed at this time. This change will reach stable Rust before even a warning about the rename will be printed. At this time this change is just the start where a new target is introduced and users can start migrating if they support only Nightly for example.
