mirror of
https://github.com/rust-lang/rust.git
synced 2025-05-14 02:49:40 +00:00
ca7d34efa9
coverage: Correctly report and check LLVM's coverage mapping version I was puzzled by the fact that the LLVM 18 update (#120055) didn't need to modify this version check, despite the fact that LLVM 18 uses a newer version of the coverage mapping format. This turned out to be because we were inappropriately hard-coding a specific version (`Version6`) in the C++ wrapper, instead of using `CovMapVersion::CurrentVersion` to reflect the version actually used by LLVM on our behalf. This PR fixes that, and also changes the Rust-side version check to accept the new coverage mapping version used by LLVM 18, since the necessary compatibility work has already been done. --- ### Quick history of `LLVMRustCoverageMappingVersion`: - Originally it returned LLVM's `coverage::CovMapVersion::CurrentVersion`, as intended. The Rust-side code would verify it, and also embed it as the actual coverage version number in the output binary. - At some point it was changed to a hard-coded value, to work around a (now-irrelevant) compatibility issue. This was incorrect (but mostly benign), because the override should have been performed on the Rust side instead, after verifying LLVM's value. - Later contributors dutifully updated the hard-coded value, because they didn't have enough context to identify the problem. - With this PR, it once again returns LLVM's current coverage version number, and the Rust-side code checks it against an expected range. We don't override the result, but we do indicate where that override should occur if it ever becomes necessary. |
||
|---|---|---|
| .. | ||
| src | ||
| Cargo.toml | ||
| messages.ftl | ||
| README.md | ||
The codegen crate contains the code to convert from MIR into LLVM IR,
and then from LLVM IR into machine code. In general it contains code
that runs towards the end of the compilation process.
For more information about how codegen works, see the rustc dev guide.