https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82702
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- https://gcc.gnu.org/onlinedocs/gcc/Invoking-Gcov.html#Invoking-Gcov The output is a single .gcov file per .gcda file. The same documentation was in GCC 5.1.0's docs: https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Invoking-Gcov.html#Invoking-Gcov