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Zalathar opened this issue Dec 12, 2023 · 4 comments · Fixed by #118852
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A used function should have had coverage mapping data but did not #118850

Zalathar opened this issue Dec 12, 2023 · 4 comments · Fixed by #118852
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A-code-coverage Area: Source-based code coverage (-Cinstrument-coverage) C-bug Category: This is a bug. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ P-high High priority regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@Zalathar
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The immediate symptoms of #118643 were fixed by #118666, but some users reported that their builds now encounter another coverage-related ICE:

#118643 (comment)
#118643 (comment)

error: internal compiler error: compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs:98:17: A used function should have had coverage mapping data but did not: _RNvMsl_NtNtNtCsl0gwtrD5SWs_5winit13platform_impl8platform15window_delegateNtB5_19WinitWindowDelegate21window_did_resign_key
@rustbot rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label Dec 12, 2023
@Zalathar
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@rustbot label +T-compiler +A-code-coverage

@rustbot rustbot added A-code-coverage Area: Source-based code coverage (-Cinstrument-coverage) T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Dec 12, 2023
This was referenced Dec 12, 2023
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@saethlin saethlin added I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ C-bug Category: This is a bug. and removed needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. labels Dec 12, 2023
@Zalathar
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This ICE does not occur on current stable/beta, but does occur on nightly.

@rustbot label +regression-from-stable-to-nightly

@rustbot rustbot added regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. I-prioritize Issue: Indicates that prioritization has been requested for this issue. labels Dec 15, 2023
@Zalathar
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(This will be fixed by #118852, which is awaiting review.)

@apiraino
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WG-prioritization assigning priority (Zulip discussion).

@rustbot label -I-prioritize +P-high

@rustbot rustbot added P-high High priority and removed I-prioritize Issue: Indicates that prioritization has been requested for this issue. labels Dec 16, 2023
@bors bors closed this as completed in 418ae3e Dec 18, 2023
rust-timer added a commit to rust-lang-ci/rust that referenced this issue Dec 18, 2023
@rust-timer
Unrolled build for rust-lang#118852
470180f 
Rollup merge of rust-lang#118852 - Zalathar:no-spans, r=cjgillot

coverage: Skip instrumenting a function if no spans were extracted from MIR

The immediate symptoms of rust-lang#118643 were fixed by rust-lang#118666, but some users reported that their builds now encounter another coverage-related ICE:

```
error: internal compiler error: compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs:98:17: A used function should have had coverage mapping data but did not: (...)
```

I was able to reproduce at least one cause of this error: if no relevant spans could be extracted from a function, but the function contains `CoverageKind::SpanMarker` statements, then codegen still thinks the function is instrumented and complains about the fact that it has no coverage spans.

This PR prevents that from happening in two ways:
- If we didn't extract any relevant spans from MIR, skip instrumenting the entire function and don't create a `FunctionCoverateInfo` for it.
- If coverage codegen sees a `CoverageKind::SpanMarker` statement, skip it early and avoid creating `func_coverage`.

---

Fixes rust-lang#118850.
@ben1009 ben1009 mentioned this issue Jan 12, 2024
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This was referenced Jan 16, 2024
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ti-chi-bot bot pushed a commit to PingCAP-QE/ci that referenced this issue Jan 17, 2024
@glorv
tikv: fix code coverage script (#2748)
3cf73f3 
After this change we still need to wait tikv to update the rust
toolchain to a newer version before this script can succeed due to
rust-lang/rust#118850
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Labels
A-code-coverage Area: Source-based code coverage (-Cinstrument-coverage) C-bug Category: This is a bug. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ P-high High priority regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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coverage: Skip instrumenting a function if no spans were extracted from MIR Zalathar/rust
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@apiraino @saethlin @Zalathar @rustbot