preserve SIMD element type information
Preserve the SIMD element type and provide it to LLVM for better optimization.
This is relevant for AArch64 types like `int16x4x2_t`, see also https://github.com/llvm/llvm-project/issues/181514. Such types are defined like so:
```rust
#[repr(simd)]
struct int16x4_t([i16; 4]);
#[repr(C)]
struct int16x4x2_t(pub int16x4_t, pub int16x4_t);
```
Previously this would be translated to the opaque `[2 x <8 x i8>]`, with this PR it is instead `[2 x <4 x i16>]`. That change is not relevant for the ABI, but using the correct type prevents bitcasts that can (indeed, do) confuse the LLVM pattern matcher.
This change will make it possible to implement the deinterleaving loads on AArch64 in a portable way (without neon-specific intrinsics), which means that e.g. Miri or the cranelift backend can run them without additional support.
discussion at [#t-compiler > loss of vector element type information](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/loss.20of.20vector.20element.20type.20information/with/584483611)
Start using pattern types in libcore
cc rust-lang/rust#135996
Replaces the innards of `NonNull` with `*const T is !null`.
This does affect LLVM's optimizations, as now reading the field preserves the metadata that the field is not null, and transmuting to another type (e.g. just a raw pointer), will also preserve that information for optimizations. This can cause LLVM opts to do more work, but it's not guaranteed to produce better machine code.
Once we also remove all uses of rustc_layout_scalar_range_start from rustc itself, we can remove the support for that attribute entirely and handle all such needs via pattern types
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.
Invert dependency between `rustc_errors` and `rustc_abi`.
Currently, `rustc_errors` depends on `rustc_abi`, which depends on `rustc_error_messages`. This is a bit odd.
`rustc_errors` depends on `rustc_abi` for a single reason: `rustc_abi` defines a type `TargetDataLayoutErrors` and `rustc_errors` impls `Diagnostic` for that type.
We can get a more natural relationship by inverting the dependency, moving the `Diagnostic` trait upstream. Then `rustc_abi` defines `TargetDataLayoutErrors` and also impls `Diagnostic` for it. `rustc_errors` is already pretty far upstream in the crate graph, it doesn't hurt to push it a little further because errors are a very low-level concept.
r? @davidtwco
hwaddress: automatically add `-Ctarget-feature=+tagged-globals`
Note that since HWAddressSanitizer is/should be a target modifier, we do not have to worry about whether this LLVM target feature changes the ABI.
Fixes: rust-lang/rust#148185
test `#[naked]` with `#[link_section = "..."]` on windows
As a part of https://github.com/rust-lang/rust/pull/147811 I ran into that we actually don't match (current) LLVM output.
r? @mati865
Because the things in this module aren't MIR and don't use anything
from `rustc_middle::mir`. Also, modules that use `mono` often don't use
anything else from `rustc_middle::mir`.
Rollup of 9 pull requests
Successful merges:
- rust-lang/rust#153440 (Various LTO cleanups)
- rust-lang/rust#151899 (Constify fold, reduce and last for iterator)
- rust-lang/rust#154561 (Suggest similar keyword when visibility is not followed by an item)
- rust-lang/rust#154657 (Fix pattern assignment suggestions for uninitialized bindings)
- rust-lang/rust#154717 (Fix ICE in unsafe binder discriminant helpers)
- rust-lang/rust#154722 (fix(lints): Improve `ill_formed_attribute_input` with better help message)
- rust-lang/rust#154777 (`#[cfg]`: suggest alternative `target_` name when the value does not match)
- rust-lang/rust#154849 (Promote `char::is_case_ignorable` from perma-unstable to unstable)
- rust-lang/rust#154850 (ast_validation: scalable vectors okay for rustdoc)
Various LTO cleanups
* Move some special casing of thin local LTO into a single location.
* Move lto_import_only_modules handling for fat LTO earlier. There is no reason to keep it separate until right before pass the LTO modules to the codegen backend. For thin LTO this introduces `ThinLtoInput` to correctly handle incr comp caching.
* Remove the `Linker` type from cg_llvm. It previously helped deduplicate code for `-Zcombine-cgus`, but that flag no longer exists.
Part of https://github.com/rust-lang/compiler-team/issues/908
Remove `Clone` impl for `StableHashingContext`.
`HashStable::hash_stable` takes a `&mut Hcx`. In contrast, `ToStableHashKey::to_stable_hash_key` takes a `&Hcx`. But there are some places where the latter calls the former, and due to the mismatch a `clone` call is required to get a mutable `StableHashingContext`.
This commit changes `to_stable_hash_key` to instead take a `&mut Hcx`. This eliminates the mismatch, the need for the clones, and the need for the `Clone` impls.
r? @fee1-dead
Instead of just using regular struct lowering for these types, which
results in an incorrect ABI (e.g. returning indirectly), use
`BackendRepr::ScalableVector` which will lower to the correct type and
be passed in registers.
This also enables some simplifications for generating alloca of scalable
vectors and greater re-use of `scalable_vector_parts`.
A LLVM codegen test demonstrating the changed IR this generates is
included in the next commit alongside some intrinsics that make these
tuples usable.
`HashStable::hash_stable` takes a `&mut Hcx`. In contrast,
`ToStableHashKey::to_stable_hash_key` takes a `&Hcx`. But there are
some places where the latter calls the former, and due to the mismatch a
`clone` call is required to get a mutable `StableHashingContext`.
This commit changes `to_stable_hash_key` to instead take a `&mut Hcx`.
This eliminates the mismatch, the need for the clones, and the need for
the `Clone` impls.
Use `Hcx`/`hcx` consistently for `StableHashingContext`.
The `HashStable` and `ToStableHashKey` traits both have a type parameter that is sometimes called `CTX` and sometimes called `HCX`. (In practice this type parameter is always instantiated as `StableHashingContext`.) Similarly, variables with these types are sometimes called `ctx` and sometimes called `hcx`. This inconsistency has bugged me for some time.
The `HCX`/`hcx` form is more informative (the `H`/`h` indicates what type of context it is) and it matches other cases like `tcx`, `dcx`, `icx`.
Also, RFC 430 says that type parameters should have names that are "concise UpperCamelCase, usually single uppercase letter: T". In this case `H` feels insufficient, and `Hcx` feels better.
Therefore, this commit changes the code to use `Hcx`/`hcx` everywhere.
r? @petrochenkov
The `HashStable` and `ToStableHashKey` traits both have a type parameter
that is sometimes called `CTX` and sometimes called `HCX`. (In practice
this type parameter is always instantiated as `StableHashingContext`.)
Similarly, variables with these types are sometimes called `ctx` and
sometimes called `hcx`. This inconsistency has bugged me for some time.
The `HCX`/`hcx` form is more informative (the `H`/`h` indicates what
type of context it is) and it matches other cases like `tcx`, `dcx`,
`icx`.
Also, RFC 430 says that type parameters should have names that are
"concise UpperCamelCase, usually single uppercase letter: T". In this
case `H` feels insufficient, and `Hcx` feels better.
Therefore, this commit changes the code to use `Hcx`/`hcx` everywhere.
Error enum names should not be plural. Even though there are multiple
possible errors, each instance of an error enum describes a single
error. There are dozens of singular error enum names, and only two
plural error enum names. This commit makes them both singular.
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!
Pass -pg to linker when using -Zinstrument-mcount
This selects a slightly different crt on gnu targets which enables the profiler within glibc.
This makes using gprof a little easier with Rust binaries. Otherwise, rustc must be passed `-Clink-args=-pg` to ensure the correct startup code is linked.
Rename `target.abi` to `target.cfg_abi` and enum-ify llvm_abiname
See [Zulip](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/De-spaghettifying.20ABI.20controls/with/578893542) for more context. Discussed a bit in https://github.com/rust-lang/rust/pull/153769#discussion_r2934399038 too.
This renames `target.abi` to `target.cfg_abi` to make it less likely that someone will use it to determine things about the actual ccABI, i.e. the calling convention used on the target. `target.abi` does not control that calling convention, it just *sometimes* informs the user about that calling convention (and also about other aspects of the ABI).
Also turn llvm_abiname into an enum to make it more natural to match on.
Cc @workingjubilee @madsmtm
target specs: stricter checks for LLVM ABI values, and correlate that with cfg(target_abi)
This tightens the checks for `llvm_abiname`, `llvm_floatabi` and `rustc_abi` in our target specs. Those are the fields that actually control the ccABI. With this commit, we now have an allowlist of value for these fields for all architectures (we previously only had that for some architectures). We also check that `cfg(target_abi)` suitably correlates with the actual ccABI. I based this check on our in-tree targets. For all ccABIs where we had a bunch of "random" values that don't directly correlate to the ccABI (like "uwp"), I also allowed `cfg(target_abi)` to remain empty, and whenever it is allowed to be empty I also allowed arbitrary other values for JSON targets. However, there's still a risk that JSON targets will fail this new check -- the idea is that we'll then get bugreports and can adjust the check as needed.
I had to adjust the target specs for non-ARM32 Apple targets as those were all setting `llvm_floatabi`, which to my knowledge makes no sense -- LLVM only actually does anything with that field on ARM32. I also adjusted the target specs for MIPS32 targets: one of them was setting llvm_abiname, and then it seems safer and more consistent to set that for all targets, so I set it to "o32" everywhere which seems to be the default.
Cc @workingjubilee
Folkert de Vries