Fix `-Ctarget-feature`s getting ignored after `crt-static`
The current behaviour introduced by commit a50a3b8e31 would discard any target features specified after `crt-static` (the only member of `RUSTC_SPECIFIC_FEATURES`). This is because it returned instead of continuing processing the next feature.
I wasn't entirely sure how the regression test should look like, but this one should do. If anyone has some suggestions, I'm happy to learn, it's my first test :)
I've confirmed that the test fails without the fix on `powerpc64le-unknown-linux-musl` and `x86_64-unknown-linux-gnu`.
cc ``@RalfJung``
The conversation in 143502 made be realize how easy this is to handle, since the only possibilty is ZSTs -- everything else ends up with the destination being `LocalKind::Memory` and thus doesn't call `codegen_rvalue_operand` at all.
This gets us perilously close to a world where `rvalue_creates_operand` only ever returns true. I'll try out such a world next :)
Simplify discriminant codegen for niche-encoded variants which don't wrap across an integer boundary
Inspired by rust-lang/rust#139729, this attempts to be a much-simpler and more-localized change while still making a difference. (Specifically, this does not try to solve the problem with select-sinking, leaving that to be fixed by https://github.com/llvm/llvm-project/issues/134024 -- once it gets released -- instead of in rustc's codegen.)
What this *does* improve is checking for the variant in a 3+ variant enum when that variant is the type providing the niche. Something like `if let Foo::WithBool(_) = ...` previously compiled to `ugt(add(x, -2), 2)`, which is non-trivial to think about because it's depending on the unsigned wrapping to shift the 0/1 up above 2. With this PR it compiles to just `ult(x, 2)`, which is probably what you'd have written yourself if you were doing it by hand to look for "is this byte a bool?".
That's done by leaving most of the codegen alone, but adding a couple new special cases to the `is_niche` check. The default looks at the relative discriminant, but in the common cases where there's no wraparound involved, we can just check the original value, rather than the offsetted one.
The first commit just adds some tests, so the best way to see the effect of this change is to look at the second commit and how it updates the test expectations.
The current behaviour introduced by commit
a50a3b8e31 would discard any
target features specified after crt-static (the only member of
RUSTC_SPECIFIC_FEATURES). This is because it returned instead of
continuing processing the next flag.
Signed-off-by: Jens Reidel <adrian@travitia.xyz>
pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests
Exported symbols are added as GC roots in linking, so `--gc-sections` won't hurt `-Zexport-executable-symbols`.
Fixes the run-make test to work on Linux. Enable the ui test on more targets.
cc rust-lang/rust#84161
fix `-Zsanitizer=kcfi` on `#[naked]` functions
fixes https://github.com/rust-lang/rust/issues/143266
With `-Zsanitizer=kcfi`, indirect calls happen via generated intermediate shim that forwards the call. The generated shim preserves the attributes of the original, including `#[unsafe(naked)]`. The shim is not a naked function though, and violates its invariants (like having a body that consists of a single `naked_asm!` call).
My fix here is to match on the `InstanceKind`, and only use `codegen_naked_asm` when the instance is not a `ReifyShim`. That does beg the question whether there are other `InstanceKind`s that could come up. As far as I can tell the answer is no: calling via `dyn` seems to work find, and `#[track_caller]` is disallowed in combination with `#[naked]`.
r? codegen
````@rustbot```` label +A-naked
cc ````@maurer```` ````@rcvalle````
Various refactors to the LTO handling code
In particular reducing the sharing of code paths between fat and thin-LTO and making the fat LTO implementation more self-contained. This also moves some autodiff handling out of cg_ssa into cg_llvm given that Enzyme only works with LLVM anyway and an implementation for another backend may do things entirely differently. This will also make it a bit easier to split LTO handling out of the coordinator thread main loop into a separate loop, which should reduce the complexity of the coordinator thread.
Rollup of 9 pull requests
Successful merges:
- rust-lang/rust#143403 (Port several trait/coherence-related attributes the new attribute system)
- rust-lang/rust#143633 (fix: correct assertion to check for 'noinline' attribute presence before removal)
- rust-lang/rust#143647 (Clarify and expand documentation for std::sys_common dependency structure)
- rust-lang/rust#143716 (compiler: doc/comment some codegen-for-functions interfaces)
- rust-lang/rust#143747 (Add target maintainer information for aarch64-unknown-linux-musl)
- rust-lang/rust#143759 (Fix typos in function names in the `target_feature` test)
- rust-lang/rust#143767 (Bump `src/tools/x` to Edition 2024 and some cleanups)
- rust-lang/rust#143769 (Remove support for SwitchInt edge effects in backward dataflow)
- rust-lang/rust#143770 (build-helper: clippy fixes)
r? `@ghost`
`@rustbot` modify labels: rollup
Make UB transmutes really UB in LLVM
Ralf suggested in <https://github.com/rust-lang/rust/pull/143410#discussion_r2184928123> that UB transmutes shouldn't be trapping, which happened for the one path *that* PR was changing, but there's another path as well, so *this* PR changes that other path to match.
r? codegen
use `--dynamic-list` for exporting executable symbols
closesrust-lang/rust#101610
cc rust-lang/rust#84161https://sourceware.org/binutils/docs-2.39/ld/VERSION.html:
> --dynamic-list=dynamic-list-file
Specify the name of a dynamic list file to the linker. This is typically used when creating shared libraries to specify a list of global symbols whose references shouldn’t be bound to the definition within the shared library, or creating dynamically linked executables to specify a list of symbols which should be added to the symbol table in the executable. This option is only meaningful on ELF platforms which support shared libraries.
`ld.lld --help`:
> --dynamic-list=<file>: Similar to --export-dynamic-symbol-list. When creating a shared object, this additionally implies -Bsymbolic but does not set DF_SYMBOLIC
> --export-dynamic-symbol-list=file: Read a list of dynamic symbol patterns. Apply --export-dynamic-symbol on each pattern
> --export-dynamic-symbol=glob: (executable) Put matched symbols in the dynamic symbol table. (shared object) References to matched non-local STV_DEFAULT symbols shouldn't be bound to definitions within the shared object. Does not imply -Bsymbolic.
> --export-dynamic: Put symbols in the dynamic symbol table
Use `--dynamic-list` because it's older than `--export-dynamic-symbol-list` (binutils 2.35)
try-job: dist-i586-gnu-i586-i686-musl
Let `rvalue_creates_operand` return true for *all* `Rvalue::Aggregate`s
~~Draft for now because it's built on Ralf's rust-lang/rust#143291~~
Inspired by https://github.com/rust-lang/rust/pull/138759#discussion_r2156375342 where I noticed that we were nearly at this point, plus the comments I was writing in rust-lang/rust#143410 that reminded me a type-dependent `true` is fine.
This PR splits the `OperandRef::builder` logic out to a separate type, with the updates needed to handle SIMD as well. In doing so, that makes the existing `Aggregate` path in `codegen_rvalue_operand` capable of handing SIMD values just fine.
As a result, we no longer need to do layout calculations for aggregate result types when running the analysis to determine which things can be SSA in codegen.
Port several linking (linkage?) related attributes the new attribute system
This ports:
- `#[export_stable]`
- `#[ffi_const]`
- `#[ffi_pure]`
- `#[rustc_std_internal_symbol]`
Part of rust-lang/rust#131229
r? ``@oli-obk``
Now that `#[used(linker)]` is the default on ELF, we don't need to use the
`-znostart-stop-gc` link-arg workaround to match bfd's behavior when
using lld.
This stabilizes a subset of the `-Clinker-features` components on x64 linux:
the lld opt-out.
The opt-in is not stabilized, as interactions with other stable flags require
more internal work, but are not needed for stabilizing using rust-lld by default.
Similarly, since we only switch to rust-lld on x64 linux, the opt-out is
only stabilized there. Other targets still require `-Zunstable-options`
to use it.
Inspired by <https://github.com/rust-lang/rust/pull/138759#discussion_r2156375342> where I noticed that we were nearly at this point, plus the comments I was writing in 143410 that reminded me a type-dependent `true` is fine.
This PR splits the `OperandRef::builder` logic out to a separate type, with the updates needed to handle SIMD as well. In doing so, that makes the existing `Aggregate` path in `codegen_rvalue_operand` capable of handing SIMD values just fine.
As a result, we no longer need to do layout calculations for aggregate result types when running the analysis to determine which things can be SSA in codegen.
Allow custom default address spaces and parse `p-` specifications in the datalayout string
Some targets, such as CHERI, use as default an address space different from the "normal" default address space `0` (in the case of CHERI, [200 is used](https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-877.pdf)). Currently, `rustc` does not allow to specify custom address spaces and does not take into consideration [`p-` specifications in the datalayout string](https://llvm.org/docs/LangRef.html#langref-datalayout).
This patch tries to mitigate these problems by allowing targets to define a custom default address space (while keeping the default value to address space `0`) and adding the code to parse the `p-` specifications in `rustc_abi`. The main changes are that `TargetDataLayout` now uses functions to refer to pointer-related informations, instead of having specific fields for the size and alignment of pointers in the default address space; furthermore, the two `pointer_size` and `pointer_align` fields in `TargetDataLayout` are replaced with an `FxHashMap` that holds info for all the possible address spaces, as parsed by the `p-` specifications.
The potential performance drawbacks of not having ad-hoc fields for the default address space will be tested in this PR's CI run.
r? workingjubilee
Fix short linker error output
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
```
