At the moment sccache does not try to cache C/C++ compiler invocations with the -fprofile-use flag. However, that would be rather useful for cases where profile data is cached by a build system (instead of regenerated for every build).

It looks like implementing this shouldn't be too hard using the existing ExtraHashFile infrastructure. But one caveat there is that profile data files can become rather big (tens of megabytes are not uncommon). I suspect that re-hashing all that data for each compiler invocation is not very fast.

Does sccache have some kind of mechanism to cache such file hashes (and only re-hash if the file in question has changed)?

cc @luser