C mode fontification took 50 seconds

C mode fontification took 50 seconds

[Richard Stallman]

Using the latest version of Emacs 22 files, in a 48-line Linux console,
I visited the file xdisp.c and typed C-u 23402 C-n.
Then I typed C-v and waited.

After it had gone on for 30 seconds, I stopped the process and looked
at it with GDB.  xbacktrace gives c-syntactic-skip-backward,
c-in-knr-argdecl, c-beginning-of-decl-1, further up
c-beginning-of-defun, further up, c-parse-state,
c-font-lock-complex-decl-prepare.  This was called
from font-lock-fontify-keywords-region.

It looks like c-in-knr-argdecl has the infinite loop.

After I continued, it eventually finished, but yuck!

This is reproducible.

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Re: C mode fontification took 50 seconds

[Glenn Morris]

Richard Stallman wrote:

> Using the latest version of Emacs 22 files, in a 48-line Linux console,
> I visited the file xdisp.c and typed C-u 23402 C-n.
> Then I typed C-v and waited.

It takes no noticeable time for me on a 1.7GHz laptop. Did you
bootstrap? Failure to do so has been seen to cause spurious cc-mode
issues in the past.


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Re: C mode fontification took 50 seconds

[Richard Stallman]

    It takes no noticeable time for me on a 1.7GHz laptop. Did you
    bootstrap?

I just about never bootstrap, since I already have compiled Lisp files.
I will try that now and see if it makes the problem go away.

Re: C mode fontification took 50 seconds

[Richard Stallman]

Bootstrapping made the problem go away.  So I deleted that item
from FOR-RELEASE.

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Re: C mode fontification took 50 seconds

[Alan Mackenzie]

Hi, Richard!

On Sat, Apr 28, 2007 at 02:35:30PM -0400, Richard Stallman wrote:
> Using the latest version of Emacs 22 files, in a 48-line Linux console,
> I visited the file xdisp.c and typed C-u 23402 C-n.
> Then I typed C-v and waited.
> 
> After it had gone on for 30 seconds, I stopped the process and looked
> at it with GDB.  xbacktrace gives c-syntactic-skip-backward,
> c-in-knr-argdecl, c-beginning-of-decl-1, further up
> c-beginning-of-defun, further up, c-parse-state,
> c-font-lock-complex-decl-prepare.  This was called
> from font-lock-fontify-keywords-region.
 
> It looks like c-in-knr-argdecl has the infinite loop.
 
> After I continued, it eventually finished, but yuck!

> This is reproducible.

I don't have this problem.

I made a change to CC Mode on 2007-04-09 to make C-x n d
(`narrow-to-defun') and friends do the right thing.  This involved
changing some macros; all users of the macros therefore needed
recompiling.  

Here, again, is the recipe for recompiling the CC Mode sources: 

(i) M-x byte-compile-file cc-defs.el.  M-x load-file /path/cc-defs.elc
(ii) M-x byte-compile-file cc-langs.el.  M-x load-file /path/cc-langs.elc
(iii) M-x byte-compile-file cc-engine.el.  M-x load-file ../cc-engine.elc
(iv) M-x byte-compile-file cc-mode.el.  M-x load-file ../cc-mode.elc

(v) compile and load cc-{awk,cmds}.el (no dependence on the other four
files).

Either do that, or recompile the entire lot off cc-*.el.  If that
doesn't fix things, please say so.

-- 
Alan Mackenzie (Munich, Germany)