bug#1024: Large C++ files load slowly, regardless of font-lock-maximum-size

[John W]

> Could you please have a look at the description of bug#851
>
> http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=851
>
> and try the recipe proposed there by Chong Yidong?

Sure.  I tried this patch

+++ cc-engine.el        2008/04/01 21:41:21     1.56.2.11

but it made no difference; it is still slow, and when I examine the
stack, it is the same stack trace.  The file loads in 2 seconds in
fundamental mode, but takes about 2 minutes in C++ mode.  I should
have mentioned that this is a preprocessed C++ file, with many
compiler directies, such as #line 1 "somefile.h", and I now think the
problem is provoked by the compiler directives.

If I globally replace the #line stuff like so:

  #line 1 "some_file.h"
 -->
  s = "some_file.h"

the file loads in about 7 seconds.

- John