Bug in font-lock? Was: QA for CPerl 5.2

[Ilya Zakharevich]

[A complimentary Cc of this posting was sent to
Randy W. Sims
<RandyS@thepierianspring.org>], who wrote in article 
<435556D7.7030303@thepierianspring.org>:
> One wierd problem I find is if I load two copies of a certain file it 
> becomes develishly slow to do anything, even scrolling. This doesn't 
> seem to happen on all files; not sure if it's size or content related yet.

I suspect it is a bug in font-lock.el: in the copy I have
`font-lock-fontify-anchored-keywords' uses the variable `limit' to set
text-property 'font-lock-multiline.  I would think it should have used
not this estimate from above, but the actual value of (point) after
doing the `while' loop for this purpose.

This bug may cause a major slow-down, although I do not know why it
shows only with two buffers in CPerl mode...

It is hard to work-around this bug; one needs a way to calculate the
limit in advance, which may be tricky.  I need to think more about
this...

Thanks,
Ilya