We compile each test file to LLVM IR assembly, and then pass that IR to a dedicated program that can decode LLVM coverage maps and print them in a more human-readable format. We can then check that output against known-good snapshots. This test suite has some advantages over the existing `run-coverage` tests: - We can test coverage instrumentation without needing to run target binaries. - We can observe subtle improvements/regressions in the underlying coverage mappings that don't make a visible difference to coverage reports.
This directory contains some source code for the Rust project, including:
- The bootstrapping build system
- Various submodules for tools, like cargo, tidy, etc.
For more information on how various parts of the compiler work, see the rustc dev guide.