如何在userspace enable gcov
1. Add gcc parmater "-fprofile-arcs and -ftest-coverage flags" and compile the program.
2. Run the programer, will generate gcno data.
3. Use the command gcc *.c can see the coverage total data.
Use the lcov -d -c -o test.info
4. Generate HTML
genhtml test.info -o html_test (folder)
