c-find-decl-spots

[Po Lu]

I've been encountering some files that cause C Mode to become
pathologically slow.  The most I can determine is that after each edit,
`font-lock-fontify-keywords-region' calls the CC Mode fontification
machinery, which then spends a lot of time in `c-find-decl-spots'.

My guess is that some cache machinery in that function is not working as
intended.  I haven't figured out how to debug this any further.  Any
help would be appreciated.

Thanks in advance.