Imported Upstream version 5.18.0.161

Former-commit-id: 4db48158d3a35497b8f118ab21b5f08ac3d86d98

external/llvm/test/tools/llvm-cov/Inputs/README

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+These inputs were pre-generated to allow for easier testing of llvm-cov.
+
+The files used to test the gcov compatible code coverage tool were generated
+using the following method:
+
+  test.gcno and test.gcda were create by running clang:
+    clang++ -g -ftest-coverage -fprofile-arcs test.cpp
+
+  test.cpp.gcov was created by running gcov 4.2.1:
+    gcov test.cpp
+
+The 'covmapping' files that are used to test llvm-cov contain raw sections
+with the coverage mapping data generated by the compiler and linker. They are
+created by running clang and llvm-cov:
+  clang++ -fprofile-instr-generate -fcoverage-mapping -o test test.cpp
+  llvm-cov convert-for-testing -o test.covmapping test
+
+The 'profdata' files were generated by running an instrumented version of the
+program and merging the raw profile data using llvm-profdata.
+  ./test
+  llvm-profdata merge -o test.profdata default.profraw