Add `minicore` test auxiliary and support `//@ add-core-stubs` directive in ui/assembly/codegen tests #130693

jieyouxu · 2024-09-22T08:14:46Z

Context: Real cross-compiling tests instead of #![no_core] silliness #130375
MCP: rust-lang/compiler-team#786
Tracking issue: #131485

This prototype PR is subject to further changes based on feedback.

New `minicore` test auxiliary and `//@ add-core-stubs` compiletest directive

This PR introduces a prototype implementation of a minicore auxiliary test helper that provides core stubs for #![no_core] ui/assembly/codegen tests that need to build but not run on both the host platform and the cross-compiled target platform.

Key summary:

tests/auxiliary/minicore.rs contains stub definitions of core items intended for consumption by check-pass/build-pass tests that want the typical prelude items like Copy to be stubbed out under #![no_core] scenarios, so that the test can be built (not run) for cross-compiled target platforms. Such tests don't want nor need full -Z build-std (e.g. tests/ui/abi/compatibility.rs).
minicore is intended for core items only, not std- or alloc-exclusive items. If stubs for alloc or std are wanted, they should be provided by an additional directive and test auxiliary, and not be conflated with minicore or core stubs. This is because a wider range of tests can benefit from core-only stubs.

Implementation

The minicore auxiliary is a single source file tests/auxiliary/minicore.rs.
The path to minicore is made avaiable from bootstrap to compiletest via the --minicore-path compiletest flag.
minicore is then built on-demand via the //@ add-core-stubs compiletest directive, for each test revision for the given target platform (this distinction is important for when host platform != target platform in cross-compilation scenario).
minicore is then made available to the test as an extern prelude.

Example usage

// tests/ui/abi/my-abi-test.rs

//@ check-pass
//@ add-core-stubs
//@ compile-flags: --target i686-unknown-linux-gnu
//@ needs-llvm-components: x86

#![feature(no_core, lang_items)]
#![no_std]
#![no_core]
#![allow(unused, internal_features)]

extern crate minicore;
use minicore::*;

#[lang = "clone"]
pub trait Clone: Sized {      // `Sized` is provided by `minicore`
    fn clone(&self) -> Self;
}

Implementation steps

1. Add an initial minicore test auxiliary.
2. Build minicore in bootstrap.
3. Setup a --minicore-path compiletest cli flag and pass minicore build artifact path from bootstrap to compiletest.
4. Assert add-core-stubs is mutually incompatible with tests that require to be run, as the stubs are only good for tests that only need to be built (i.e. no run-{pass,fail}).
5. Add some self-tests to sanity check the behavior.
6. Ensure that tests/auxiliary/minicore.rs is input stamped, i.e. modifying tests/auxiliary/minicore.rs should invalidate test cache and force the test to be rerun.

Known limitations

The current minicore is very minimal, because this PR is intended to focus on supporting the test infrastructure first. Further stubs could be added in follow-up PRs and/or on a as-needed basis.

try-job: aarch64-apple
try-job: armhf-gnu
try-job: x86_64-msvc
try-job: test-various
try-job: dist-various-1

jieyouxu · 2024-09-22T08:20:10Z

@bors try

[PROTOTYPE] Add minicore test auxiliary and support `//@ use-minicore` directive in ui/assembly/codegen tests **TODO: work in progress prototype implementation, opened early for MCP to reference** Context: [Real cross-compiling tests instead of `#![no_core]` silliness rust-lang#130375](rust-lang#130375) This PR introduces a prototype implementation of `minicore` auxiliary test helper. `minicore` contains stub definitions of std/core prelude items intended for consumption by tests that want the typical prelude items like `Copy` or `Result` in cross-compilation scenarios, but don't want nor need full `-Z build-std` (e.g. `tests/ui/abi/compatibility.rs`). The `minicore` auxiliary is a single source file `tests/auxiliary/minicore.rs`. The path to this auxiliary is made avaiable from bootstrap to compiletest via the `--minicore-path` compiletest flag. The `minicore` auxiliary is then built, on demand via `//@ use-minicore` compiletest directives, for each test revision for the given target (this distinction is important for when host != target in cross-compilation scenario). ### Implementation steps - [ ] 1. File an MCP to describe `tests/auxiliary/minicore.rs`, `--minicore-path` compiletest flag, `//@ use-minicore` compiletest directive and the behavior. - [ ] 2. And some self-tests to sanity check the behavior. - [ ] 3. Update rustc-dev-guide to describe the new `use-minicore` directive and provide an example, noting that `use-minicore` both requires `no_std` + `no_core` and implies `-C panic=abort` for the test file. r? `@ghost` (not yet ready for full review, still needs some self-tests and some try-jobs) (TODO: cc interested people once this passes initial try jobs in cross-compilation scenarios) cc `@/workingjubilee` `@/RalfJung` `@/nikic` `@/chrisnc` (if this makes sense to you in terms of functionality and UX) try-job: aarch64-apple try-job: armhf-gnu try-job: x86_64-msvc try-job: test-various try-job: dist-various-1

bors · 2024-09-22T08:21:21Z

⌛ Trying commit 9d6f01a with merge 01b2fff...

bors · 2024-09-22T09:12:27Z

💔 Test failed - checks-actions

bjorn3 · 2024-09-22T10:15:02Z

tests/auxiliary/minicore.rs

+pub struct ManuallyDrop<T: ?Sized> {
+    value: T,
+}
+impl<T: Copy + ?Sized> Copy for ManuallyDrop<T> {}


You can derive Copy if you add

#[rustc_builtin_macro] pub macro Copy($item:item) { /* compiler built-in */ }

and the same applies to Clone.

I did not make this change because I couldn't figure out how to make use of this, just kept manual impl Copy for ... for now.

tests/auxiliary/minicore.rs

jieyouxu · 2024-09-28T13:50:05Z

Changes since last review:

Fixed bootstrap path of tests/auxiliary/minicore.rs to be constructed from a builder.src prefix.
Trimmed minicore.rs to only include a minimal subset of core items, excluding the ones that are easy to abuse like #[rustc_layout_scalar_valid_range_start(1)] or #[rustc_nonnull_optimization_guaranteed].
Made sure no alloc or std-specific items get included in minicore.
Removed cfg(host) and cfg(non(host)) distinction in tests/abi/compatibility.rs, and just unconditionally stub out core items. Not sure if this is desirable.
Fixed minicore doc comments to no longer mention std, instead emphasize core items only. Also added remarks about rustc-attribute-annotated core items.

src/bootstrap/src/core/build_steps/test.rs

src/tools/compiletest/src/common.rs

src/tools/compiletest/src/header.rs

jieyouxu · 2024-09-28T14:27:23Z

src/tools/compiletest/src/runtest.rs


+    /// Builds `minicore`. Returns the path to the minicore rlib within the base test output
+    /// directory.
+    fn build_minicore(&self) -> PathBuf {


Remark: I don't like how convoluted the top-level runtest logic is, but intended for future compiletest cleanup PRs instead of this PR.

src/tools/compiletest/src/runtest.rs

tests/auxiliary/minicore.rs

bjorn3 · 2024-10-31T10:01:19Z

r=me with the above change applied.

The initial `minicore` is intentionally super minimal and contains an incomplete subset of `core` items, and explicitly not items from `alloc` or `std`-only items.

…st module

… directive

…lude when requested via `//@ add-core-stubs` directive `//@ add-core-stubs` will imply `-Cpanic=abort`.

Check that `minicore` cannot be used with `run-{pass,fail}` tests.

bjorn3 · 2024-10-31T10:40:44Z

@bors r+

bors · 2024-10-31T10:40:47Z

📌 Commit adb6d47 has been approved by bjorn3

It is now in the queue for this repository.

Add `minicore` test auxiliary and support `//@ add-core-stubs` directive in ui/assembly/codegen tests Context: [Real cross-compiling tests instead of `#![no_core]` silliness rust-lang#130375](rust-lang#130375) MCP: rust-lang/compiler-team#786 Tracking issue: rust-lang#131485 This prototype PR is subject to further changes based on feedback. ### New `minicore` test auxiliary and `//@ add-core-stubs` compiletest directive This PR introduces a prototype implementation of a `minicore` auxiliary test helper that provides `core` stubs for `#![no_core]` ui/assembly/codegen tests that need to build but not run on both the host platform and the cross-compiled target platform. Key summary: - `tests/auxiliary/minicore.rs` contains stub definitions of `core` items intended for consumption by `check-pass`/`build-pass` tests that want the typical prelude items like `Copy` to be stubbed out under `#![no_core]` scenarios, so that the test can be built (not run) for cross-compiled target platforms. Such tests don't want nor need full `-Z build-std` (e.g. `tests/ui/abi/compatibility.rs`). - `minicore` is intended for `core` items **only**, not `std`- or `alloc`-exclusive items. If stubs for `alloc` or `std` are wanted, they should be provided by an additional directive and test auxiliary, and not be conflated with `minicore` or `core` stubs. This is because a wider range of tests can benefit from `core`-only stubs. ### Implementation - The `minicore` auxiliary is a single source file `tests/auxiliary/minicore.rs`. - The path to `minicore` is made avaiable from bootstrap to compiletest via the `--minicore-path` compiletest flag. - `minicore` is then built on-demand via the `//@ add-core-stubs` compiletest directive, for each test revision for the given target platform (this distinction is important for when host platform != target platform in cross-compilation scenario). - `minicore` is then made available to the test as an [extern prelude]. [extern prelude]: https://doc.rust-lang.org/reference/names/preludes.html#extern-prelude ### Example usage ```rs // tests/ui/abi/my-abi-test.rs //@ check-pass //@ add-core-stubs //@ compile-flags: --target i686-unknown-linux-gnu //@ needs-llvm-components: x86 #![feature(no_core, lang_items)] #![no_std] #![no_core] #![allow(unused, internal_features)] extern crate minicore; use minicore::*; #[lang = "clone"] pub trait Clone: Sized { // `Sized` is provided by `minicore` fn clone(&self) -> Self; } ``` ### Implementation steps - [x] 1. Add an initial `minicore` test auxiliary. - [x] 2. Build `minicore` in bootstrap. - [x] 3. Setup a `--minicore-path` compiletest cli flag and pass `minicore` build artifact path from bootstrap to compiletest. - [x] 4. Assert `add-core-stubs` is mutually incompatible with tests that require to be `run`, as the stubs are only good for tests that only need to be built (i.e. no `run-{pass,fail}`). - [x] 5. Add some self-tests to sanity check the behavior. - [x] 6. Ensure that `tests/auxiliary/minicore.rs` is input stamped, i.e. modifying `tests/auxiliary/minicore.rs` should invalidate test cache and force the test to be rerun. ### Known limitations - The current `minicore` is very minimal, because this PR is intended to focus on supporting the test infrastructure first. Further stubs could be added in follow-up PRs and/or on a as-needed basis. try-job: aarch64-apple try-job: armhf-gnu try-job: x86_64-msvc try-job: test-various try-job: dist-various-1

…iaskrgr Rollup of 5 pull requests Successful merges: - rust-lang#130693 (Add `minicore` test auxiliary and support `//@ add-core-stubs` directive in ui/assembly/codegen tests) - rust-lang#132316 (CI: use free runners for 3 fast windows jobs) - rust-lang#132354 (Add `lp64e` RISC-V ABI) - rust-lang#132395 (coverage: Avoid ICE when `coverage_cx` is unexpectedly unavailable) - rust-lang#132396 (CI: use free runners for x86_64-gnu-tools and x86_64-rust-for-linux) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#130693 - jieyouxu:minicore, r=bjorn3 Add `minicore` test auxiliary and support `//@ add-core-stubs` directive in ui/assembly/codegen tests Context: [Real cross-compiling tests instead of `#![no_core]` silliness rust-lang#130375](rust-lang#130375) MCP: rust-lang/compiler-team#786 Tracking issue: rust-lang#131485 This prototype PR is subject to further changes based on feedback. ### New `minicore` test auxiliary and `//@ add-core-stubs` compiletest directive This PR introduces a prototype implementation of a `minicore` auxiliary test helper that provides `core` stubs for `#![no_core]` ui/assembly/codegen tests that need to build but not run on both the host platform and the cross-compiled target platform. Key summary: - `tests/auxiliary/minicore.rs` contains stub definitions of `core` items intended for consumption by `check-pass`/`build-pass` tests that want the typical prelude items like `Copy` to be stubbed out under `#![no_core]` scenarios, so that the test can be built (not run) for cross-compiled target platforms. Such tests don't want nor need full `-Z build-std` (e.g. `tests/ui/abi/compatibility.rs`). - `minicore` is intended for `core` items **only**, not `std`- or `alloc`-exclusive items. If stubs for `alloc` or `std` are wanted, they should be provided by an additional directive and test auxiliary, and not be conflated with `minicore` or `core` stubs. This is because a wider range of tests can benefit from `core`-only stubs. ### Implementation - The `minicore` auxiliary is a single source file `tests/auxiliary/minicore.rs`. - The path to `minicore` is made avaiable from bootstrap to compiletest via the `--minicore-path` compiletest flag. - `minicore` is then built on-demand via the `//@ add-core-stubs` compiletest directive, for each test revision for the given target platform (this distinction is important for when host platform != target platform in cross-compilation scenario). - `minicore` is then made available to the test as an [extern prelude]. [extern prelude]: https://doc.rust-lang.org/reference/names/preludes.html#extern-prelude ### Example usage ```rs // tests/ui/abi/my-abi-test.rs //@ check-pass //@ add-core-stubs //@ compile-flags: --target i686-unknown-linux-gnu //@ needs-llvm-components: x86 #![feature(no_core, lang_items)] #![no_std] #![no_core] #![allow(unused, internal_features)] extern crate minicore; use minicore::*; #[lang = "clone"] pub trait Clone: Sized { // `Sized` is provided by `minicore` fn clone(&self) -> Self; } ``` ### Implementation steps - [x] 1. Add an initial `minicore` test auxiliary. - [x] 2. Build `minicore` in bootstrap. - [x] 3. Setup a `--minicore-path` compiletest cli flag and pass `minicore` build artifact path from bootstrap to compiletest. - [x] 4. Assert `add-core-stubs` is mutually incompatible with tests that require to be `run`, as the stubs are only good for tests that only need to be built (i.e. no `run-{pass,fail}`). - [x] 5. Add some self-tests to sanity check the behavior. - [x] 6. Ensure that `tests/auxiliary/minicore.rs` is input stamped, i.e. modifying `tests/auxiliary/minicore.rs` should invalidate test cache and force the test to be rerun. ### Known limitations - The current `minicore` is very minimal, because this PR is intended to focus on supporting the test infrastructure first. Further stubs could be added in follow-up PRs and/or on a as-needed basis. try-job: aarch64-apple try-job: armhf-gnu try-job: x86_64-msvc try-job: test-various try-job: dist-various-1

workingjubilee · 2024-10-26T19:36:55Z

tests/ui/abi/compatibility.rs

This is much nicer! Thank you.

jieyouxu force-pushed the minicore branch from 58bef84 to 9d6f01a Compare September 22, 2024 08:16

jieyouxu mentioned this pull request Sep 22, 2024

Support tests to use minicore std/core prelude stubs rust-lang/compiler-team#786

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jieyouxu added S-waiting-on-MCP Status: PR has a compiler MCP and is waiting for the compiler MCP to complete. and removed needs-mcp This change is large enough that it needs a major change proposal before starting work. labels Sep 22, 2024

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Real cross-compiling tests instead of #![no_core] silliness #130375

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Add a run-make test for Arm target-cpu features. #130382

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jieyouxu force-pushed the minicore branch 2 times, most recently from 34e9887 to df03437 Compare September 28, 2024 13:46

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jieyouxu changed the title ~~[PROTOTYPE] Add minicore test auxiliary and support //@ use-minicore directive in ui/assembly/codegen tests~~ Add minicore test auxiliary and support //@ use-minicore directive in ui/assembly/codegen tests Sep 28, 2024

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jieyouxu unassigned albertlarsan68 Oct 31, 2024

jieyouxu and others added 10 commits October 31, 2024 18:20

minicore: add minimal minicore test auxiliary

82c2e42

The initial `minicore` is intentionally super minimal and contains an incomplete subset of `core` items, and explicitly not items from `alloc` or `std`-only items.

bootstrap: pass minicore path when running compiletest step

f9ca420

compiletest: localize compile_test_and_save_assembly to assembly te…

74c0c48

…st module

compiletest: register --minicore-path flag and //@ add-core-stubs…

95d01fc

… directive

compiletest: conditionally build and provide minicore as extern pre…

a737f75

…lude when requested via `//@ add-core-stubs` directive `//@ add-core-stubs` will imply `-Cpanic=abort`.

compiletest: stamp minicore.rs to rerun tests on changes

59cb59d

tests/assembly: add minicore compiletest self-test

b115a22

Check that `minicore` cannot be used with `run-{pass,fail}` tests.

tests/codegen: add minicore compiletest self-test

a8b34f5

tests/ui: add minicore compiletest self-test

0bbe07e

tests: use minicore in tests/ui/abi/compatibility.rs as an example

adb6d47

jieyouxu force-pushed the minicore branch from 4e56a84 to adb6d47 Compare October 31, 2024 10:24

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 31, 2024

This was referenced Oct 31, 2024

Rollup of 5 pull requests #132399

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Rollup of 5 pull requests #132401

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bors merged commit 2da5560 into rust-lang:master Oct 31, 2024
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jieyouxu deleted the minicore branch October 31, 2024 15:30

workingjubilee mentioned this pull request Nov 3, 2024

rust_for_linux: -Zreg-struct-return commandline flag for X86 (#116973) #130777

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This is much nicer! Thank you.

jieyouxu added the A-test-infra-minicore Area: `minicore` test auxiliary and `//@ add-core-stubs` label Apr 23, 2025

RalfJung mentioned this pull request Oct 20, 2025

Rename //@ add-core-stubs to //@ add-minicore rust-lang/compiler-team#930

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Add minicore test auxiliary and support //@ add-core-stubs directive in ui/assembly/codegen tests #130693

Add minicore test auxiliary and support //@ add-core-stubs directive in ui/assembly/codegen tests #130693

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New minicore test auxiliary and //@ add-core-stubs compiletest directive

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Add `minicore` test auxiliary and support `//@ add-core-stubs` directive in ui/assembly/codegen tests #130693

Add `minicore` test auxiliary and support `//@ add-core-stubs` directive in ui/assembly/codegen tests #130693

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New `minicore` test auxiliary and `//@ add-core-stubs` compiletest directive

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