add `extern "custom"` functions
tracking issue: rust-lang/rust#140829
previous discussion: https://github.com/rust-lang/rust/issues/140566
In short, an `extern "custom"` function is a function with a custom ABI, that rust does not know about. Therefore, such functions can only be defined with `#[unsafe(naked)]` and `naked_asm!`, or via an `extern "C" { /* ... */ }` block. These functions cannot be called using normal rust syntax: calling them can only be done from inline assembly.
The motivation is low-level scenarios where a custom calling convention is used. Currently, we often pick `extern "C"`, but that is a lie because the function does not actually respect the C calling convention.
At the moment `"custom"` seems to be the name with the most support. That name is not final, but we need to pick something to actually implement this.
r? `@traviscross`
cc `@tgross35`
try-job: x86_64-apple-2
retpoline and retpoline-external-thunk flags (target modifiers) to enable retpoline-related target features
`-Zretpoline` and `-Zretpoline-external-thunk` flags are target modifiers (tracked to be equal in linked crates).
* Enables target features for `-Zretpoline-external-thunk`:
`+retpoline-external-thunk`, `+retpoline-indirect-branches`, `+retpoline-indirect-calls`.
* Enables target features for `-Zretpoline`:
`+retpoline-indirect-branches`, `+retpoline-indirect-calls`.
It corresponds to clang -mretpoline & -mretpoline-external-thunk flags.
Also this PR forbids to specify those target features manually (warning).
Issue: rust-lang/rust#116852
Stabilize keylocker
This PR stabilizes the feature flag `keylocker_x86` (tracking issue rust-lang/rust#134813).
# Public API
The 2 `x86` target features `kl` and `widekl`, and the associated intrinsics in stdarch.
These target features are very specialized, and are only used to signal the presence of the corresponding CPU instruction. They don't have any nontrivial interaction with the ABI (contrary to something like AVX), and serve the only purpose of enabling 11 stdarch intrinsics, all of which have been implemented and propagated to rustc via a stdarch submodule update.
Also, these were added way back in LLVM12, and as the minimum LLVM required for rustc is LLVM19, we are safe in that front too!
# Associated PRs
- rust-lang/rust#134814
- rust-lang/stdarch#1706
- rust-lang/rust#136831 (stdarch submodule update)
- rust-lang/stdarch#1795 (stabilizing the runtime detection and intrinsics)
- rust-lang/rust#141964 (stdarch submodule update for the stabilization of the runtime detection and intrinsics)
As all of the required tasks have been done (adding the target features to rustc, implementing their runtime detection in std_detect and implementing the associated intrinsics in core_arch), these target features can be stabilized now.
cc ````@rust-lang/lang````
cc ````@rust-lang/libs-api```` for the intrinsics and runtime detection
I don't think anyone else worked on this feature, so no one else to ping, maybe cc ````@Amanieu.```` I will send the reference pr soon.
Stabilize `sha512`, `sm3` and `sm4` for x86
This PR stabilizes the feature flag `sha512_sm_x86` (tracking issue rust-lang/rust#126624).
# Public API
The 3 `x86` target features `sha512`, `sm3` and `sm4`, and the associated intrinsics in stdarch.
These target features are very specialized, and are only used to signal the presence of the corresponding CPU instruction. They don't have any nontrivial interaction with the ABI (contrary to something like AVX), and serve the only purpose of enabling 10 stdarch intrinsics, all of which have been implemented and propagated to rustc via a stdarch submodule update.
Also, these were added in LLVM17, and as the minimum LLVM required for rustc is LLVM19, we are safe in that front too!
# Associated PRs
- rust-lang/rust#126704
- rust-lang/stdarch#1592
- rust-lang/stdarch#1790
- rust-lang/rust#140389 (stdarch submodule update)
- rust-lang/stdarch#1796 (stabilizing the runtime detection and intrinsics)
- rust-lang/rust#141964 (stdarch submodule update for the stabilization of the runtime detection and intrinsics)
As all of the required tasks have been done (adding the target features to rustc, implementing their runtime detection in std_detect and implementing the associated intrinsics in core_arch), these target features can be stabilized now.
cc `@rust-lang/lang`
cc `@rust-lang/libs-api` for the intrinsics and runtime detection
I don't think anyone else worked on this feature, so no one else to ping, maybe cc `@Amanieu.` I will send the reference pr soon.
Add (back) `unsupported_calling_conventions` lint to reject more invalid calling conventions
This adds back the `unsupported_calling_conventions` lint that was removed in https://github.com/rust-lang/rust/pull/129935, in order to start the process of dealing with https://github.com/rust-lang/rust/issues/137018. Specifically, we are going for the plan laid out [here](https://github.com/rust-lang/rust/issues/137018#issuecomment-2672118326):
- thiscall, stdcall, fastcall, cdecl should only be accepted on x86-32
- vectorcall should only be accepted on x86-32 and x86-64
The difference to the status quo is that:
- We stop accepting stdcall, fastcall on targets that are windows && non-x86-32 (we already don't accept these on targets that are non-windows && non-x86-32)
- We stop accepting cdecl on targets that are non-x86-32
- (There is no difference for thiscall, this was already a hard error on non-x86-32)
- We stop accepting vectorcall on targets that are windows && non-x86-*
Vectorcall is an unstable ABI so we can just make this a hard error immediately. The others are stable, so we emit the `unsupported_calling_conventions` forward-compat lint. I set up the lint to show up in dependencies via cargo's future-compat report immediately, but we could also make it show up just for the local crate first if that is preferred.
try-job: i686-msvc-1
try-job: x86_64-msvc-1
try-job: test-various
store `target.min_global_align` as an `Align`
Parse the alignment properly when the target is defined/parsed, and error out on invalid alignment values. That means this work doesn't need to happen for every global in each backend.
compiler: set Apple frame pointers by architecture
All Apple targets stop overriding this configuration and instead use the default base of FramePointer::NonLeaf, which means some Apples will have less frame pointers in leaf functions.
r? ``@madsmtm``
cc ``@thomcc``
Apple targets can now overriding this configuration and instead use the
default based on their architecture, which means aarch64 targets now
have less frame pointers in leaf functions.
x86 (32/64): go back to passing SIMD vectors by-ptr
Fixes https://github.com/rust-lang/rust/issues/139029 by partially reverting https://github.com/rust-lang/rust/pull/135408 and going back to passing SIMD vectors by-ptr on x86. Sadly, by-val confuses the LLVM inliner so much that it's not worth it...
Also fixes https://github.com/rust-lang/rust/issues/141848 by no longer actually using vector registers with the "Rust" ABI.
r? `@tgross35`
Cc `@nikic`
try-job: `test-various*`
try-job: dist-i586-gnu-i586-i686-musl
try-job: x86_64-gnu-nopt
try-job: `x86_64-msvc*`
try-job: `i686-msvc*`
Replace ad-hoc ABI "adjustments" with an `AbiMap` to `CanonAbi`
Our `conv_from_spec_abi`, `adjust_abi`, and `is_abi_supported` combine to give us a very confusing way of reasoning about what _actual_ calling convention we want to lower our code to and whether we want to compile the resulting code at all. Instead of leaving this code as a miniature adventure game in which someone tries to combine stateful mutations into a Rube Goldberg machine that will let them escape the maze and arrive at the promised land of codegen, we let `AbiMap` devour this complexity. Once you have an `AbiMap`, you can answer which `ExternAbi`s will lower to what `CanonAbi`s (and whether they will lower at all).
Removed:
- `conv_from_spec_abi` replaced by `AbiMap::canonize_abi`
- `adjust_abi` replaced by same
- `Conv::PreserveAll` as unused
- `Conv::Cold` as unused
- `enum Conv` replaced by `enum CanonAbi`
target-spec.json changes:
- If you have a target-spec.json then now your "entry-abi" key will be specified in terms of one of the `"{abi}"` strings Rust recognizes, e.g.
```json
"entry-abi": "C",
"entry-abi": "win64",
"entry-abi": "aapcs",
```
Stabilize the avx512 target features
This PR stabilizes the AVX512 target features - see [this comment](https://github.com/rust-lang/rust/issues/111137#issuecomment-2745821279).
Tracking Issue - #44839
The target feature UI tests have been changed to `x87` (chosen because this is very unlikely to stablize ever, please comment if some other feature will be better)
related: #111137
[win][arm64] Remove 'Arm64 Hazard' undocumented MSVC option and instead disable problematic test
PR #140758 added the undocumented `/arm64hazardfree` MSVC linker flag to work around a test failure where LLVM generated code that would trip a hazard in an outdated ARM processor.
Adding this flag caused issues with LLD, as it doesn't recognize it.
Rethinking the issue, using the undocumented flag seems like the incorrect solution: there's no guarantee that the flag won't be removed in the future, or change its meaning.
Instead, I've disabled the problematic test for Arm64 Windows and have filed a bug with the MSVC team to have the check removed: <https://developercommunity.microsoft.com/t/Remove-checking-for-and-fixing-Cortex-A/10905134>
This PR supersedes #140977
r? ```@jieyouxu```
Unfortunately, multiple people are reporting linker warnings related to
`__rust_no_alloc_shim_is_unstable` after this change. The solution isn't
quite clear yet, let's revert to green for now, and try a reland with a
determined solution for `__rust_no_alloc_shim_is_unstable`.
This reverts commit c8b7f32434c0306db5c1b974ee43443746098a92, reversing
changes made to 667247db71ea18c4130dd018d060e7f09d589490.
Stage0 bootstrap update
This PR [follows the release process](https://forge.rust-lang.org/release/process.html#master-bootstrap-update-tuesday) to update the stage0 compiler.
The only thing of note is 58651d1b31, which was flagged by clippy as a correctness fix. I think allowing that lint in our case makes sense, but it's worth to have a second pair of eyes on it.
r? `@Mark-Simulacrum`
