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merged 1 commit into from
Jun 28, 2025
Merged

Insert checks for enum discriminants when debug assertions are enabled #141759

merged 1 commit into from
Jun 28, 2025

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@1c3t3a 1c3t3a commented May 30, 2025 •
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Similar to the existing null-pointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following:

let val: MyEnum = unsafe { std::mem::transmute<u32, MyEnum>(42) };

An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++.

This check is similar to Miri's capabilities of checking for valid construction of enum values.

This PR is inspired by saethlin@'s PR
#104862. Thank you so much for keeping this code up and the detailed comments!

I also pair-programmed large parts of this together with vabr-g@.

r? @saethlin

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels May 30, 2025
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rustbot commented May 30, 2025

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

This PR changes MIR

cc @oli-obk, @RalfJung, @JakobDegen, @davidtwco, @vakaras

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

rust-analyzer is developed in its own repository. If possible, consider making this change to rust-lang/rust-analyzer instead.

cc @rust-lang/rust-analyzer

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@1c3t3a 1c3t3a force-pushed the discriminants-query branch from 1225079 to c52f534 Compare June 6, 2025 19:54
@bors 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 Jun 27, 2025
@1c3t3a 1c3t3a mentioned this pull request Jun 27, 2025
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1c3t3a commented Jun 27, 2025

FYI: all further updates to this check are tracked in #143087.

bors added a commit that referenced this pull request Jun 28, 2025
@bors
Auto merge of #141759 - 1c3t3a:discriminants-query, r=saethlin
eac4ca2 
Insert checks for enum discriminants when debug assertions are enabled

Similar to the existing null-pointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following:
```rust
let val: MyEnum = unsafe { std::mem::transmute<u32, MyEnum>(42) };
```

An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++.

This check is similar to Miri's capabilities of checking for valid construction of enum values.

This PR is inspired by saethlin@'s PR
#104862. Thank you so much for keeping this code up and the detailed comments!

I also pair-programmed large parts of this together with vabr-g@.

r? `@saethlin`
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bors commented Jun 28, 2025

⌛ Testing commit 1087042 with merge eac4ca2...

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looks like its stuck
@bors retry r-

@bors bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 28, 2025
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@bors r=@saethlin

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bors commented Jun 28, 2025

📌 Commit 1087042 has been approved by saethlin

It is now in the queue for this repository.

@bors 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 28, 2025
bors added a commit that referenced this pull request Jun 28, 2025
@bors
Auto merge of #141759 - 1c3t3a:discriminants-query, r=saethlin
1f9b61c 
Insert checks for enum discriminants when debug assertions are enabled

Similar to the existing null-pointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following:
```rust
let val: MyEnum = unsafe { std::mem::transmute<u32, MyEnum>(42) };
```

An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++.

This check is similar to Miri's capabilities of checking for valid construction of enum values.

This PR is inspired by saethlin@'s PR
#104862. Thank you so much for keeping this code up and the detailed comments!

I also pair-programmed large parts of this together with vabr-g@.

r? `@saethlin`
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bors commented Jun 28, 2025

⌛ Testing commit 1087042 with merge 1f9b61c...

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bors commented Jun 28, 2025

⌛ Testing commit 1087042 with merge b63223c...

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bors commented Jun 28, 2025

☀️ Test successful - checks-actions
Approved by: saethlin
Pushing b63223c to master...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Jun 28, 2025
@bors bors merged commit b63223c into rust-lang:master Jun 28, 2025
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@rustbot rustbot added this to the 1.90.0 milestone Jun 28, 2025
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What is this? This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing d41e12f (parent) -> b63223c (this PR)

Test differences

Show 56 test diffs

Stage 1

  • [ui] tests/ui/mir/enum/convert_non_enum_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/convert_non_enum_niche_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/convert_non_enum_niche_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/convert_non_enum_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/niche_option_tuple_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/niche_option_tuple_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/numbered_variants_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/numbered_variants_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/option_with_bigger_niche_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/option_with_bigger_niche_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/plain_no_data_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/plain_no_data_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/single_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/single_with_repr_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/single_with_repr_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/with_niche_int_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/with_niche_int_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/with_niche_ptr_ok.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/wrap_break.rs: [missing] -> pass (J0)
  • [ui] tests/ui/mir/enum/wrap_ok.rs: [missing] -> pass (J0)

Stage 2

  • [ui] tests/ui/mir/enum/convert_non_enum_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/convert_non_enum_niche_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/convert_non_enum_niche_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/convert_non_enum_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/niche_option_tuple_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/niche_option_tuple_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/numbered_variants_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/numbered_variants_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/option_with_bigger_niche_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/option_with_bigger_niche_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/plain_no_data_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/plain_no_data_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/single_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/single_with_repr_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/single_with_repr_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/with_niche_int_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/with_niche_int_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/with_niche_ptr_ok.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/wrap_break.rs: [missing] -> pass (J1)
  • [ui] tests/ui/mir/enum/wrap_ok.rs: [missing] -> pass (J1)

Additionally, 16 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard b63223c152212832ce37a109e26cc5f84c577532 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

  1. x86_64-apple-2: 4991.5s -> 3249.6s (-34.9%)
  2. x86_64-apple-1: 6732.2s -> 8791.0s (30.6%)
  3. mingw-check-1: 1784.0s -> 1525.7s (-14.5%)
  4. i686-gnu-2: 6282.9s -> 5375.5s (-14.4%)
  5. dist-aarch64-apple: 6203.2s -> 5314.1s (-14.3%)
  6. x86_64-rust-for-linux: 2876.5s -> 2529.2s (-12.1%)
  7. aarch64-gnu-debug: 4037.6s -> 3563.2s (-11.7%)
  8. i686-gnu-nopt-1: 8017.5s -> 7098.3s (-11.5%)
  9. x86_64-gnu-llvm-20-1: 3628.4s -> 3222.4s (-11.2%)
  10. x86_64-gnu-aux: 6464.3s -> 5776.4s (-10.6%)
How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

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Finished benchmarking commit (b63223c): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

mean range count
Regressions ❌
(primary)		 0.1% [0.1%, 0.1%] 1
Regressions ❌
(secondary)		 - - 0
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 - - 0
All ❌✅ (primary) 0.1% [0.1%, 0.1%] 1

Max RSS (memory usage)

Results (secondary -0.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

mean range count
Regressions ❌
(primary)		 - - 0
Regressions ❌
(secondary)		 2.3% [2.3%, 2.3%] 1
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 -2.4% [-2.7%, -2.2%] 2
All ❌✅ (primary) - - 0

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 690.233s -> 690.587s (0.05%)
Artifact size: 372.05 MiB -> 372.13 MiB (0.02%)

This was referenced Jun 29, 2025
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@carolynzech carolynzech mentioned this pull request Jun 30, 2025
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github-merge-queue bot pushed a commit to model-checking/kani that referenced this pull request Jun 30, 2025
@carolynzech
Upgrade toolchain to 06/30 (#4188)
6bd6afa 
Culprit PRs:

- rust-lang/rust#142927
- rust-lang/rust#141759

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under the terms of the Apache 2.0 and MIT licenses.
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github-actions bot pushed a commit to model-checking/verify-rust-std that referenced this pull request Jul 4, 2025
@bors
Auto merge of rust-lang#141759 - 1c3t3a:discriminants-query, r=saethlin
bee72cf 
Insert checks for enum discriminants when debug assertions are enabled

Similar to the existing null-pointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following:
```rust
let val: MyEnum = unsafe { std::mem::transmute<u32, MyEnum>(42) };
```

An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++.

This check is similar to Miri's capabilities of checking for valid construction of enum values.

This PR is inspired by saethlin@'s PR
rust-lang#104862. Thank you so much for keeping this code up and the detailed comments!

I also pair-programmed large parts of this together with vabr-g@.

r? `@saethlin`
@1c3t3a 1c3t3a mentioned this pull request Jul 25, 2025
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