php被require的文件是啥时候转成opcode的

syntax_exception.php

     20 echo "enter\n";
     21 require_once "./code_contain_syntax_err.php";
     22 echo "done\n";

code_contain_syntax_err.php

     20  $a = 1
     21  $c = $a;
     22  echo "c=$c\n";

php syntax_exception.php

输出了enter

说明是require后再编译