Hello Yafar_iSi,
if a segmentation fault occurs, you usually don’t get any output at all even if you have set the highest debug/verbosity level. You could use a debugger like xdebug to step thru the code and see where it breaks. You can also edit the platform/src/Storefront/Theme/ThemeCompiler.php and insert a exit() call to see until which point the code gets executed and when the segmentation fault occurs.
Best regards
Jens