Sized Hierarchy: Part I
This patch implements the non-const parts of rust-lang/rfcs#3729. It introduces two new traits to the standard library, `MetaSized` and `PointeeSized`. See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.
These traits are unstable (as is their constness), so users cannot refer to them without opting-in to `feature(sized_hierarchy)`. These traits are not behind `cfg`s as this would make implementation unfeasible, there would simply be too many `cfg`s required to add the necessary bounds everywhere. So, like `Sized`, these traits are automatically implemented by the compiler.
RFC 3729 describes changes which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:
- `?Sized` is rewritten as `MetaSized`
- `MetaSized` is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.
There are no edition migrations implemented in this, as these are primarily required for the constness parts of the RFC and prior to stabilisation of this (and so will come in follow-up PRs alongside the const parts). All diagnostic output should remain the same (showing `?Sized` even if the compiler sees `MetaSized`) unless the `sized_hierarchy` feature is enabled.
Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax `Deref::Target` (this will be investigated separately).
It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Some details might leak through due to the standard library relaxations, but this has not been observed in test output.
**Notes:**
- Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
- This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
- Each commit has a short description describing its purpose.
- This patch is large but it's primarily in the test suite.
- I've worked on the performance of this patch and a few optimisations are implemented so that the performance impact is neutral-to-minor.
- `PointeeSized` is a different name from the RFC just to make it more obvious that it is different from `std::ptr::Pointee` but all the names are yet to be bikeshed anyway.
- `@nikomatsakis` has confirmed [that this can proceed as an experiment from the t-lang side](https://rust-lang.zulipchat.com/#narrow/channel/435869-project-goals/topic/SVE.20and.20SME.20on.20AArch64.20.28goals.23270.29/near/506196491)
- FCP in https://github.com/rust-lang/rust/pull/137944#issuecomment-2912207485Fixesrust-lang/rust#79409.
r? `@ghost` (I'll discuss this with relevant teams to find a reviewer)
Implement `//@ needs-target-std` compiletest directive
Closesrust-lang/rust#141863.
Needed to unblock rust-lang/rust#139244 and rust-lang/rust#141856.
### Summary
This PR implements a `//@ needs-target-std` compiletest directive that gates test execution based on whether the target supports std or not. For some cases, this should be preferred over e.g. some combination of `//@ ignore-none`, `//@ ignore-nvptx` and more[^none-limit].
### Implementation limitation
Unfortunately, since there is currently [no reliable way to determine from metadata whether a given target supports std or not](https://github.com/rust-lang/rust/issues/142296), we have to resort to a hack. Bootstrap currently determines whether or not a target supports std by a naive target tuple substring comparison: a target supports std if its target tuple does *not* contain one of `["-none", "nvptx", "switch"]` substrings. This PR simply pulls that hack out into `build_helpers` to avoid reimplementing the same hack in compiletest, and uses that logic to inform `//@ needs-target-std`.
### Auxiliary changes
This PR additionally changes a few run-make tests to use `//@ needs-target-std` over an inconsistent combination of target-based `ignore`s. This should help with rust-lang/rust#139244.
---
r? bootstrap
[^none-limit]: Notably, `target_os = "none"` is **not** a sufficient condition for "target does not support std"
Many of `std`'s dependency have a dependency on the crates.io
`compiler-builtins` when used with the feature
`rustc-std-workspace-core`. Use a Cargo patch to select the in-tree
version instead.
`compiler-builtins` is also added as a dependency of
`rustc-std-workspace-core` so these crates can remove their crates.io
dependency in the future.
Allow `#![doc(test(attr(..)))]` everywhere
This PR adds the ability to specify [`#![doc(test(attr(..)))]`](https://doc.rust-lang.org/nightly/rustdoc/write-documentation/the-doc-attribute.html#testattr) ~~at module level~~ everywhere in addition to allowing it at crate-root.
This is motivated by a recent PR #140323 (by ````@tgross35)```` where we have to duplicate 2 attributes to every single `f16` and `f128` doctests, by allowing `#![doc(test(attr(..)))]` at module level (and everywhere else) we can omit them entirely and just have (in both module):
```rust
#![doc(test(attr(feature(cfg_target_has_reliable_f16_f128))))]
#![doc(test(attr(expect(internal_features))))]
```
Those new attributes are appended to the one found at crate-root or at a previous module. Those "global" attributes are compatible with merged doctests (they already were before).
Given the small addition that this is, I'm proposing to insta-stabilize it, but I can feature-gate it if preferred.
Best reviewed commit by commit.
r? ````@GuillaumeGomez````
Stabilize `repr128`
## Stabilisation report
The `repr128` feature ([tracking issue](https://github.com/rust-lang/rust/issues/56071)) allows the use of `#[repr(u128)]` and `#[repr(i128)]` on enums in the same way that other primitive representations such as `#[repr(u64)]` can be used. For example:
```rust
#[repr(u128)]
enum Foo {
One = 1,
Two,
Big = u128::MAX,
}
#[repr(i128)]
enum Bar {
HasThing(u16) = 42,
HasSomethingElse(i64) = u64::MAX as i128 + 1,
HasNothing,
}
```
This is the final part of adding 128-bit integers to Rust ([RFC 1504](https://rust-lang.github.io/rfcs/1504-int128.html)); all other parts of 128-bit integer support were stabilised in #49101 back in 2018.
From a design perspective, `#[repr(u128)]`/`#[repr(i128)]` function like `#[repr(u64)]`/`#[repr(i64)]` but for 128-bit integers instead of 64-bit integers. The only differences are:
- FFI safety: as `u128`/`i128` are not currently considered FFI safe, neither are `#[repr(u128)]`/`#[repr(i128)]` enums (I discovered this wasn't the case while drafting this stabilisation report, so I have submitted #138282 to fix this).
- Debug info: while none of the major debuggers currently support 128-bit integers, as of LLVM 20 `rustc` will emit valid debuginfo for both DWARF and PDB (PDB makes use of the same natvis that is also used for all enums with fields, whereas DWARF has native support).
Tests for `#[repr(u128)]`/`#[repr(i128)]` enums include:
- [ui/enum-discriminant/repr128.rs](385970f0c1/tests/ui/enum-discriminant/repr128.rs): checks that 128-bit enum discriminants have the correct values.
- [debuginfo/msvc-pretty-enums.rs](385970f0c1/tests/debuginfo/msvc-pretty-enums.rs): checks the PDB debuginfo is correct.
- [run-make/repr128-dwarf](385970f0c1/tests/run-make/repr128-dwarf/rmake.rs): checks the DWARF debuginfo is correct.
Stabilising this feature does not require any changes to the Rust Reference as [the documentation on primitive representations](https://doc.rust-lang.org/nightly/reference/type-layout.html#r-layout.repr.primitive.intro) already includes `u128` and `i128`.
Closes#56071
Closes https://github.com/rust-lang/reference/issues/1368
r? lang
```@rustbot``` label +I-lang-nominated +T-lang
Method errors have an extra check that force trim paths whenever the
normal string is longer than 10 characters, which can be quite unhelpful
when multiple items have the same name (for example an `Error`).
A user reported this force trimming as being quite unhelpful when they
had a method error where the precise path of the `Error` mattered.
The code uses `tcx.short_string` already to get the normal path, which
tries to be clever around trimming paths if necessary, so there is no
reason for this extra force trimming.
8 and 16-bit integers are subject to upcasting in C, and hence are not reliably safe. users should perform their own casting and deal with the consequences
[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```
Remove #![feature(let_chains)] from library and src/librustdoc
PR https://github.com/rust-lang/rust/pull/132833 has stabilized the `let_chains` feature. This PR removes the last occurences from the library, the compiler, and librustdoc (also because #140887 missed the conditional in one of the crates as it was behind the "rustc" feature).
We keep `core` as exercise for the future as updating it is non-trivial (see PR thread).
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 c8b7f32434, reversing
changes made to 667247db71.
Fix `broken-pipe-no-ice` run-make test for rpath-less builds
The `broken-pipe-no-ice` run-make test currently fails on rpath-less builds, because host compiler runtime libs are not configured for raw std command usages.
This PR is an alternative approach to #140744. However, instead of duplicating `run_make_support::util::set_host_compiler_dylib_path` logic, we instead support "ejecting" the "configured" underlying std `Command` from `bare_rustc()` and `rustdoc()`, where host compiler runtime libs are already set.
cc `@jchecahi`
r? `@Kobzol`
rustdoc: Replace unstable flag `--doctest-compilation-args` with a simpler one: `--doctest-build-arg`
Tracking issue: https://github.com/rust-lang/rust/issues/134172.
Context: https://github.com/rust-lang/rust/pull/137096#issuecomment-2776318800
Yeets the ad hoc shell-like lexer for 'nested' program arguments.
No FCP necessary since the flag is unstable.
I've chosen to replace `compilation` with `build` because it's shorter (you now need to pass it multiple times in order to pass many arguments to the doctest compiler, so it matters a bit) and since I prefer it esthetically.
**Issue**: Even though we don't process the argument passed to `--doctest-build-arg`, we end up passing it via an argument file (`rustc `@argfile`)` which delimits arguments by line break (LF or CRLF, [via](https://doc.rust-lang.org/rustc/command-line-arguments.html#path-load-command-line-flags-from-a-path)) meaning ultimately the arguments still get split which is unfortunate. Still, I think this change is an improvement over the status quo.
I'll update the tracking issue if/once this PR merges. I'll also add the (CR)LF issue to 'unresolved question'.
r? GuillaumeGomez
r? notriddle
Where host compiler runtime libs are properly configured, instead of raw
`RUSTC`/`RUSTDOC` commands.
Co-authored-by: Jesus Checa Hidalgo <jchecahi@redhat.com>
Fix linking statics on Arm64EC
Arm64EC builds recently started to fail due to the linker not finding a symbol:
```
symbols.o : error LNK2001: unresolved external symbol #_ZN3std9panicking11EMPTY_PANIC17hc8d2b903527827f1E (EC Symbol)
C:\Code\hello-world\target\arm64ec-pc-windows-msvc\debug\deps\hello_world.exe : fatal error LNK1120: 1 unresolved externals
```
It turns out that `EMPTY_PANIC` is a new static variable that was being exported then imported from the standard library, but when exporting LLVM didn't prepend the name with `#` (as only functions are prefixed with this character), whereas Rust was prefixing with `#` when attempting to import it.
The fix is to have Rust not prefix statics with `#` when importing.
Adding tests discovered another issue: we need to correctly mark static exported from dylibs with `DATA`, otherwise MSVC's linker assumes they are functions and complains that there is no exit thunk for them.
CI found another bug: we only apply `DllImport` to non-local statics that aren't foreign items (i.e., in an `extern` block), that is we want to use `DllImport` for statics coming from other Rust crates. However, `__rust_no_alloc_shim_is_unstable` is a static generated by the Rust compiler if required, but downstream crates consider it a foreign item since it is declared in an `extern "Rust"` block, thus they do not apply `DllImport` to it and so fails to link if it is exported by the previous crate as `DATA`. The fix is to apply `DllImport` to foreign items that are marked with the `rustc_std_internal_symbol` attribute (i.e., we assume they aren't actually foreign and will be in some Rust crate).
Fixes#138541
---
try-job: dist-aarch64-msvc
try-job: dist-x86_64-msvc
try-job: x86_64-msvc-1
try-job: x86_64-msvc-2
[arm64] Pointer auth test should link with C static library statically
While trying to get the aarch64-msvc build working correctly (#140136), the `pointer-auth-link-with-c` test was failing.
The pointer auth test builds its C library statically:
3ef8e64ce9/tests/run-make/pointer-auth-link-with-c/rmake.rs (L15)
However, the Rust code did not indicate the link kind, so it defaulted to dynamic which then fails on Windows.
Fix `-Zremap-path-scope` rmeta handling
This PR fixes the conditional remapping (`-Zremap-path-scope`) of rmeta file paths ~~by using the `debuginfo` scope~~ by conditionally embedding the local path in addition to the remapped path.
Fixes https://github.com/rust-lang/rust/issues/139217
Unify the format of rustc cli flags
As mentioned in #140102, I unified the format of rustc CLI flags.
I use the following rules:
1. `<param>`: Indicates a required parameter
2. `[param]`: Indicates an optional parameter
3. `|`: Indicates a mutually exclusive option
4. `*`: a list element with description
Current output:
```bash
Usage: rustc [OPTIONS] INPUT
Options:
-h, --help Display this message
--cfg <SPEC> Configure the compilation environment.
SPEC supports the syntax `<NAME>[="<VALUE>"]`.
--check-cfg <SPEC>
Provide list of expected cfgs for checking
-L [<KIND>=]<PATH> Add a directory to the library search path. The
optional KIND can be one of
<dependency|crate|native|framework|all> (default:
all).
-l [<KIND>[:<MODIFIERS>]=]<NAME>[:<RENAME>]
Link the generated crate(s) to the specified native
library NAME. The optional KIND can be one of
<static|framework|dylib> (default: dylib).
Optional comma separated MODIFIERS
<bundle|verbatim|whole-archive|as-needed>
may be specified each with a prefix of either '+' to
enable or '-' to disable.
--crate-type <bin|lib|rlib|dylib|cdylib|staticlib|proc-macro>
Comma separated list of types of crates
for the compiler to emit
--crate-name <NAME>
Specify the name of the crate being built
--edition <2015|2018|2021|2024|future>
Specify which edition of the compiler to use when
compiling code. The default is 2015 and the latest
stable edition is 2024.
--emit <TYPE>[=<FILE>]
Comma separated list of types of output for the
compiler to emit.
Each TYPE has the default FILE name:
* asm - CRATE_NAME.s
* llvm-bc - CRATE_NAME.bc
* dep-info - CRATE_NAME.d
* link - (platform and crate-type dependent)
* llvm-ir - CRATE_NAME.ll
* metadata - libCRATE_NAME.rmeta
* mir - CRATE_NAME.mir
* obj - CRATE_NAME.o
* thin-link-bitcode - CRATE_NAME.indexing.o
--print <INFO>[=<FILE>]
Compiler information to print on stdout (or to a file)
INFO may be one of
<all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|crate-root-lint-levels|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|supported-crate-types|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models>.
-g Equivalent to -C debuginfo=2
-O Equivalent to -C opt-level=3
-o <FILENAME> Write output to FILENAME
--out-dir <DIR> Write output to compiler-chosen filename in DIR
--explain <OPT> Provide a detailed explanation of an error message
--test Build a test harness
--target <TARGET>
Target triple for which the code is compiled
-A, --allow <LINT> Set lint allowed
-W, --warn <LINT> Set lint warnings
--force-warn <LINT>
Set lint force-warn
-D, --deny <LINT> Set lint denied
-F, --forbid <LINT> Set lint forbidden
--cap-lints <LEVEL>
Set the most restrictive lint level. More restrictive
lints are capped at this level
-C, --codegen <OPT>[=<VALUE>]
Set a codegen option
-V, --version Print version info and exit
-v, --verbose Use verbose output
Additional help:
-C help Print codegen options
-W help Print 'lint' options and default settings
-Z help Print unstable compiler options
--help -v Print the full set of options rustc accepts
```
[AIX] Handle AIX dynamic library extensions within c-link-to-rust-dylib run-make test
Dynamic libraries on AIX have the ".a" extension. The c-link-to-rust-dylib run-make test checks for the extension explicitly, so the extension for AIX is also added to accommodate the test case on AIX.
Stabilize flags for doctest cross compilation
This makes the following changes in preparation for supporting doctest cross-compiling in cargo:
- Renames `--runtool` and `--runtool-arg` to `--test-runtool` and `--test-runtool-arg` to maintain consistency with other `--test-*` arguments.
- Stabilizes the `--test-runtool` and `--test-runtool-arg`. These are needed in order to support cargo's `target.runner` option which specifies a runner to execute a cross-compiled doctest (for example, qemu).
- Stabilizes the `--enable-per-target-ignores` flag by removing it and making it unconditionally enabled. This makes it possible to disable a doctest on a per-target basis, which I think will be helpful for rolling out this feature.
These changes were suggested in https://rust-lang.zulipchat.com/#narrow/channel/266220-t-rustdoc/topic/stabilizing.20doctest.20xcompile/near/409281127
The intent is to stabilize the doctest-xcompile feature in cargo. This will help ensure that for projects that do cross-compile testing that their doctests are also covered. Currently there is a somewhat surprising behavior that they are ignored.
Closes https://github.com/rust-lang/rust/issues/64245
try-job: x86_64-msvc-1
make abi_unsupported_vector_types a hard error
Fixes https://github.com/rust-lang/rust/issues/116558 by completing the transition; see that issue for context. The lint was introduced with Rust 1.84 and this has been shown in cargo's future breakage reports since Rust 1.85, released 6 weeks ago, and so far we got 0 complaints by users. There's not even a backlink on the tracking issue. We did a [crater run](https://github.com/rust-lang/rust/pull/127731#issuecomment-2286736295) when the lint was originally added and found no breakage. So I don't think we need another crater run now, but I can do one if the team prefers that.
https://github.com/rust-lang/rust/issues/131800 is done, so for most current targets (in particular, all tier 1 and tier 2 targets) we have the information to implement this check (modulo the targets where we don't properly support SIMD vectors yet, see the sub-issues of https://github.com/rust-lang/rust/issues/116558). If a new target gets added in the future, it will default to reject all SIMD vector types until proper information is added, which is the default we want.
This will need approval by for `@rust-lang/lang.` Cc `@workingjubilee` `@veluca93`
try-job: test-various
try-job: armhf-gnu
try-job: dist-i586-gnu-i586-i686-musl
Dynamic libraries on AIX have the ".a" extension. The c-link-to-rust-dylib
run-make test checks for the extension explicitly, so the extension for AIX
is also added to accommodate the test case on AIX.
Construct OutputType using macro and print [=FILENAME] help info
Closes#139805
Use define_output_types to define variants of OutputType, as well as refactor all of its methods for clarity. This way no variant is missed when pattern matching or output help messages.
On top of that, I optimized for `emit` help messages.
r? ```@jieyouxu```
Don't canonicalize crate paths
When printing paths in diagnostic we should favour printing the paths that were passed in rather than resolving all symlinks.
This PR changes the form of the crate path but it should only really affect diagnostics as filesystem functions won't care which path is used. The uncanonicalized path was already used as a fallback for when canonicalization failed.
This is a partial alternative to #139823.
