It has been found that some functions in CompilerOracle are unused.
They should be removed .
See mail communication on hotspot-dev :

>Hello, it seems that the fopen calls in >CompilerOracle::append_comment_to_file and
>CompilerOracle::append_exclude_to_file do not have a corresponding >fclose.

No, you are right, this is a bug. However, I think those functions are nowhere used, so maybe they could be removed completely.