`rustc`: `target_features`: allow for `cfg`-only stable `target_features`
This PR introduces a new stabilization level for `target_features`: `CfgOnlyStable`. The motivation is allowing the Rust compiler to expose `target_features` of targets so users can use `cfg(target_feature = "feature")` for conditional blocks depending on target features. However, `CfgOnlyStable` cannot be used for `#[target_feature(enable = "feature")]`, as this is still considered unstable. Accordingly, the compiler will still raise an error if these expressions are used on stable.
This PR relates partially to rust-lang/rust#150257. As discussed, for RISC-V targets, having the `"d"`, `"e"`, and `"f"` target features exposed will allow baremetal developers to adapt the code depending on the target's properties.
r? @RalfJung
`rustc_error_messages` currently depends on
`rustc_ast`/`rustc_ast_pretty`. This is odd, because
`rustc_error_messages` feels like a very low-level module but
`rustc_ast`/`rustc_ast_pretty` do not.
The reason is that a few AST types impl `IntoDiagArg` via
pretty-printing. `rustc_error_messages` can define `IntoDiagArg` and
then impl it for the AST types. But if we invert the dependency we hit
a problem with the orphan rule: `rustc_ast` must impl `IntoDiagArg`
for the AST types, but that requires calling pretty-printing code which
is in `rustc_ast_pretty`, a downstream crate.
This commit avoids this problem by just removing the `IntoDiagArg` impls
for these AST types. There aren't that many of them, and we can just use
`String` in the relevant error structs and use the pretty printer in the
downstream crates that construct the error structs. There are plenty of
existing examples where `String` is used in error structs.
There is now no dependency between `rustc_ast*` and
`rustc_error_messages`.
When archive format is wrong produce an error instead of ICE
Fixrust-lang/rust#145624. Fixrust-lang/rust#147094. Fixrust-lang/rust#148217.
There are now two-step solutions to replace the original ICE：
Step 1: BSD format archive on a GNU/Linux target should emit a format mismatch warning.
Step 2: Corrupt archive with member offset exceeding file boundary should produce an error, not an ICE.
r? @bjorn3
Most diagnostic types are only used within their own crate, and so have
a `pub(crate)` visibility. We have some diagnostic types that are
unnecessarily `pub`. This is bad because (a) information hiding, and (b)
if a `pub(crate)` type becomes unused the compiler will warn but it
won't warn for a `pub` type.
This commit eliminates unnecessary `pub` visibilities for some
diagnostic types, and also some related things due to knock-on effects.
(I found these types with some ad hoc use of `grep`.)
Previously `sve_cast`'s implementation was abstracted to power both
`sve_cast` and `simd_cast` which supported scalable and non-scalable
vectors respectively. In anticipation of having to do this for another
`simd_*` intrinsic, `sve_cast` is removed and `simd_cast` is changed to
accept both scalable and non-scalable intrinsics, an approach that will
scale better to the other intrinsics.
Merge `fabsf16/32/64/128` into `fabs::<F>`
Following [a small conversation on Zulip](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Float.20intrinsics/with/521501401) (and because I'd be interested in starting to contribute on Rust), I thought I'd give a try at merging the float intrinsics :)
This PR just merges `fabsf16`, `fabsf32`, `fabsf64`, `fabsf128`, as it felt like an easy first target.
Notes:
- I'm opening the PR for one intrinsic as it's probably easier if the shift is done one intrinsic at a time, but let me know if you'd rather I do several at a time to reduce the number of PRs.
- Currently this PR increases LOCs, despite being an attempt at simplifying the intrinsics/compilers. I believe this increase is a one time thing as I had to define new functions and move some things around, and hopefully future PRs/commits will reduce overall LoCs
- `fabsf32` and `fabsf64` are `#[rustc_intrinsic_const_stable_indirect]`, while `fabsf16` and `fabsf128` aren't; because `f32`/`f64` expect the function to be const, the generic version must be made indirectly stable too. We'd need to check with T-lang this change is ok; the only other intrinsics where there is such a mismatch is `minnum`, `maxnum` and `copysign`.
- I haven't touched libm because I'm not familiar with how it works; any guidance would be welcome!
Introduces `BackendRepr::ScalableVector` corresponding to scalable
vector types annotated with `repr(scalable)` which lowers to a scalable
vector type in LLVM.
Co-authored-by: Jamie Cunliffe <Jamie.Cunliffe@arm.com>
This removes the #[no_sanitize] attribute, which was behind an unstable
feature named no_sanitize. Instead, we introduce the sanitize attribute
which is more powerful and allows to be extended in the future (instead
of just focusing on turning sanitizers off).
This also makes sanitize(kernel_address = ..) attribute work with
-Zsanitize=address
To do it the same as how clang disables address sanitizer, we now
disable ASAN on sanitize(kernel_address = "off") and KASAN on
sanitize(address = "off").
The same was added to clang in https://reviews.llvm.org/D44981.
This change implements the #[sanitize(..)] attribute, which opts to
replace the currently unstable #[no_sanitize]. Essentially the new
attribute works similar as #[no_sanitize], just with more flexible
options regarding where it is applied. E.g. it is possible to turn
a certain sanitizer either on or off:
`#[sanitize(address = "on|off")]`
This attribute now also applies to more places, e.g. it is possible
to turn off a sanitizer for an entire module or impl block:
```rust
\#[sanitize(address = "off")]
mod foo {
fn unsanitized(..) {}
#[sanitize(address = "on")]
fn sanitized(..) {}
}
\#[sanitize(thread = "off")]
impl MyTrait for () {
...
}
```
This attribute is enabled behind the unstable `sanitize` feature.
Add diagnostic explaining STATUS_STACK_BUFFER_OVERRUN not only being used for stack buffer overruns if link.exe exits with that exit code
`STATUS_STACK_BUFFER_OVERRUN` is also used for fast abnormal program termination, e.g. by abort(). Emit a special diagnostic to let people know that this most likely doesn't indicate a stack buffer overrun.
This doesn't look up the crash report in the event log to determine what the fast fail error code is. This is due to the way crashes are logged: When a process crash happens, the system logs an "Application Error" event, which contains the exit code and the process ID, but not the fast fail error code. A second event by Windows Error Reporting does contain that fast fail code, but not the process ID - but that event is not emitted at process exit, but when WER has dealt with it (on my system, it happens roughly two seconds later), so querying the code would have to read the `IntegratorReportId`, wait two seconds or potentially longer for the WER event with the same `ReportID`, and read out the code. (Also, that second event doesn't happen if WER is disabled.)
Fixesrust-lang/rust#100519.
atomicrmw on pointers: move integer-pointer cast hacks into backend
Conceptually, we want to have atomic operations on pointers of the form `fn atomic_add(ptr: *mut T, offset: usize, ...)`. However, LLVM does not directly support such operations (https://github.com/llvm/llvm-project/issues/120837), so we have to cast the `offset` to a pointer somewhere.
This PR moves that hack into the LLVM backend, so that the standard library, intrinsic, and Miri all work with the conceptual operation we actually want. Hopefully, one day LLVM will gain a way to represent these operations without integer-pointer casts, and then the hack will disappear entirely.
Cc ```@nikic``` -- this is the best we can do right now, right?
Fixes https://github.com/rust-lang/rust/issues/134617
used for stack buffer overruns if link.exe exits with that exit code
`STATUS_STACK_BUFFER_OVERRUN` is also used for fast abnormal program
termination, e.g. by abort(). Emit a special diagnostic to let people
know that this most likely doesn't indicate a stack buffer overrun.
This PR does 2 things:
- It removes the braces when there's a single element. This is required since brace expansion (at
least in bash and zsh) only triggers if there's at least 2 elements.
- It removes the extra `.rlib` suffixes of the elements. See
https://github.com/rust-lang/rust/pull/135707#discussion_r2185212393 for context.
Running `cargo +stage1 build` on the following program:
```rust
unsafe extern "C" {
fn foo() -> libc::c_int;
}
fn main() {
let x = unsafe { foo() } as u32;
// println!("{}", data_encoding::BASE64.encode(&x.to_le_bytes()));
}
```
Gives the following diff before and after the PR:
```diff
-/tmp/foo/target/debug/deps/{liblibc-faf416f178830595.rlib}.rlib
+/tmp/foo/target/debug/deps/liblibc-faf416f178830595.rlib
```
Running on the same program with the additional dependency, we get the following diff:
```diff
-/tmp/foo/target/debug/deps/{liblibc-faf416f178830595.rlib,libdata_encoding-84bb5aadfa9e8839.rlib}.rlib
+/tmp/foo/target/debug/deps/{liblibc-faf416f178830595,libdata_encoding-84bb5aadfa9e8839}.rlib
```
Do we want to add a UI test?
Extract some shared code from codegen backend target feature handling
There's a bunch of code duplication between the GCC and LLVM backends in target feature handling. This moves that into new shared helper functions in `rustc_codegen_ssa`.
The first two commits should be purely refactoring. I am fairly sure the LLVM-side behavior stays the same; if the GCC side deliberately diverges from this then I may have missed that. I did account for one divergence, which I do not know is deliberate or not: GCC does not seem to use the `-Ctarget-feature` flag to populate `cfg(target_feature)`. That seems odd, since the `-Ctarget-feature` flag is used to populate the return value of `global_gcc_features` which controls the target features actually used by GCC. ``@GuillaumeGomez`` ``@antoyo`` is there a reason `target_config` ignores `-Ctarget-feature` but `global_gcc_features` does not? The second commit also cleans up a bunch of unneeded complexity added in https://github.com/rust-lang/rust/pull/135927.
The third commit extracts some shared logic out of the functions that populate `cfg(target_feature)` and the backend target feature set, respectively. This one actually has some slight functional changes:
- Before, with `-Ctarget-feature=-feat`, if there is some other feature `x` that implies `feat` we would *not* add `-x` to the backend target feature set. Now, we do. This fixesrust-lang/rust#134792.
- The logic that removes `x` from `cfg(target_feature)` in this case also changed a bit, avoiding a large number of calls to the (uncached) `sess.target.implied_target_features` (if there were a large number of positive features listed before a negative feature) but instead constructing a full inverse implication map when encountering the first negative feature. Ideally this would be done with queries but the backend target feature logic runs before `tcx` so we can't use that...
- Previously, if feature "a" implied "b" and "b" was unstable, then using `-Ctarget-feature=+a` would also emit a warning about `b`. I had to remove this since when accounting for negative implications, this emits a ton of warnings in a bunch of existing tests... I assume this was unintentional anyway.
The fourth commit increases consistency of the GCC backend with the LLVM backend.
The last commit does some further cleanup:
- Get rid of RUSTC_SPECIAL_FEATURES. It was only needed for s390x "backchain", but since LLVM 19 that is always a regular target feature so we don't need this hack any more. The hack also has various unintended side-effects so we don't want to keep it. Fixes https://github.com/rust-lang/rust/issues/142412.
- Move RUSTC_SPECIFIC_FEATURES handling into the shared parse_rust_feature_flag helper so all consumers of `-Ctarget-feature` that only care about actual target features (and not "crt-static") have it. Previously, we actually set `cfg(target_feature = "crt-static")` twice: once in the backend target feature logic, and once specifically for that one feature. IIUC, some targets are meant to ignore `-Ctarget-feature=+crt-static`, it seems like before this PR that flag still incorrectly enabled `cfg(target_feature = "crt-static")` (but I didn't test this).
- Move fixed_x18 handling together with retpoline handling.
- Forbid setting fixed_x18 as a regular target feature, even unstably. It must be set via the `-Z` flag.
``@bjorn3`` I did not touch the cranelift backend here, since AFAIK it doesn't really support target features. But if you ever do, please use the new helpers. :)
Cc ``@workingjubilee``
Wesley Wiser