rust/compiler/rustc_mir_transform
León Orell Valerian Liehr 5a38754d23
Rollup merge of #119460 - Zalathar:improper-region, r=wesleywiser
coverage: Never emit improperly-ordered coverage regions

If we emit a coverage region that is improperly ordered (end < start), `llvm-cov` will fail with `coveragemap_error::malformed`, which is inconvenient for users and also very hard to debug.

Ideally we would fix the root causes of these situations, but they tend to occur in very obscure edge-case scenarios (often involving nested macros), and we don't always have a good MCVE to work from. So it makes sense to also have a catch-all check that will prevent improperly-ordered regions from ever being emitted.

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This is mainly aimed at resolving #119453. We don't have a specific way to reproduce it, which is why I haven't been able to add a test case in this PR. But based on the information provided in that issue, this change seems likely to avoid the error in `llvm-cov`.

`````@rustbot````` label +A-code-coverage
2024-01-24 15:43:11 +01:00
..
src Rollup merge of #119460 - Zalathar:improper-region, r=wesleywiser 2024-01-24 15:43:11 +01:00
Cargo.toml coverage: Avoid unnecessary macros in unit tests 2023-12-07 11:12:48 +11:00
messages.ftl Print list of missing target features when calling a function with target features outside an unsafe block 2023-11-27 19:13:11 +01:00