Ship llvm-cov and llvm-profdata with coverage_files - #856
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The rule-based cc_toolchain's coverage_files group was empty (a TODO: action_names.bzl lists no actions for coverage), so a toolchain whose llvm_cov / llvm_profdata tools are files -- a hermetic LLVM distribution -- cannot collect llvm-format coverage: the environment points collect_cc_coverage.sh at the right execroot-relative llvm-profdata path, but the binary is not among the coverage test action's inputs, and collection fails with .../bin/llvm-profdata: No such file or directory The legacy cc_toolchain never hit this because its coverage_files attribute defaults to all_files. Toolchains whose coverage tools are absolute paths (xcrun shims, /usr/bin/gcov) are unaffected either way. Verified with toolchains_llvm's darwin toolchain: with this change, `bazel coverage --experimental_use_llvm_covmap --experimental_generate_llvm_lcov` produces a populated lcov report where it previously failed outright. Signed-off-by: Austin Schuh <austin.linux@gmail.com>
keith
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Aug 29, 2026
Same reasoning as llvm-cov and llvm-profdata: a toolchain whose gcov tool is a file rather than an absolute path needs it among the coverage test action's inputs. Signed-off-by: Austin Schuh <austin.linux@gmail.com>
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The rule-based cc_toolchain's coverage_files group was empty (a TODO: action_names.bzl lists no actions for coverage), so a toolchain whose llvm_cov / llvm_profdata tools are files -- a hermetic LLVM distribution -- cannot collect llvm-format coverage: the environment points collect_cc_coverage.sh at the right execroot-relative llvm-profdata path, but the binary is not among the coverage test action's inputs, and collection fails with
.../bin/llvm-profdata: No such file or directory
The legacy cc_toolchain never hit this because its coverage_files attribute defaults to all_files. Toolchains whose coverage tools are absolute paths (xcrun shims, /usr/bin/gcov) are unaffected either way.
Verified with toolchains_llvm's darwin toolchain: with this change,
bazel coverage --experimental_use_llvm_covmap --experimental_generate_llvm_lcovproduces a populated lcov report where it previously failed outright.