From: "Óscar Fuentes" <ofv@wanadoo.es>
To: help-gnu-emacs@gnu.org
Subject: Re: A guide on setting up C/C++ development environment for Emacs
Date: Wed, 27 Aug 2014 20:31:24 +0200 [thread overview]
Message-ID: <877g1taio3.fsf@wanadoo.es> (raw)
In-Reply-To: 657f2c39-422b-4289-a02e-3d03dc386166@googlegroups.com
solidius4747@gmail.com writes:
> Because real parsing takes time and such a task, while possible using
> Emacs Lisp, but is too much for current Emacs implementation. CEDET
> does some nice optimizations to speed it up as fast as it can: idle
> parsing, caching and incremental parsing to reduce computational time.
> Consider someone using Clang to generate tag database:
> https://github.com/drothlis/clang-ctags#performance:
>
> "Running clang-ctags over a much larger input, such as the entire llvm
> C/C++ sources (7k files, 1.8 million lines of code) took 98 minutes
> and a peak memory usage of 140MB."
>
> It's just 1.8 million lines of code. And that's Clang.
That's a problem of clang-ctags being slow, not Clang being *so* slow,
because Clang can compile its own sources on a fraction of time of those
98 minutes (15 minutes here on a 6 year old 4core machine, for an
optimized build.)
> GNU Global only
> needs a few minutes to generate tag database for Linux kernel, which
> is more than 14 million lines of code and more than 40k files. Do you
> say Clang is worse than GNU Global?
I'll say that parsing those 1.8 MLoc of C++ code is much more demanding
than parsing 14 MLoc of C code. And the level of analysis GNU Global
does is incomparable with a real compiler and it is a long stretch to
put it on the same tool category as Clang (or even Semantic's own
parser.)
GNU Global has its uses, but C++ auto completion needs Clang, which is
accurate but slow. I can't see how CEDET could be acceptably fast and
accurate at the same time.
next prev parent reply other threads:[~2014-08-27 18:31 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-27 7:05 A guide on setting up C/C++ development environment for Emacs solidius4747
2014-08-27 12:48 ` Dmitriy Igrishin
2014-08-27 13:18 ` Tu Hoang Do
2014-08-27 14:15 ` Dmitriy Igrishin
[not found] ` <CAMd9FiKzwc1QKa3KtZPFpTGs86bupRptFqL_WwCSE3kPGARXfg@mail.gmail.com>
2014-08-27 14:53 ` Fwd: " Tu Hoang Do
[not found] ` <CAAfz9KNL25WboPXG87Azd_6yVr8zrx6hNrCsmuWs6w_XTvdspQ@mail.gmail.com>
[not found] ` <CAMd9FiJyjk78a-3yMatvca3qp+pr4O+GmDp03ZqFSkpAEoxhGw@mail.gmail.com>
2014-08-27 18:14 ` Tu Hoang Do
2014-08-27 18:15 ` Jai Dayal
2014-08-27 18:37 ` Óscar Fuentes
2014-08-27 18:42 ` Jai Dayal
2014-08-27 18:42 ` Jai Dayal
2014-08-27 18:52 ` Óscar Fuentes
2014-08-27 19:05 ` Jai Dayal
2014-08-27 19:28 ` Óscar Fuentes
2014-08-27 19:32 ` Jai Dayal
2014-08-27 20:06 ` Óscar Fuentes
2014-08-27 20:11 ` Jai Dayal
2014-08-27 20:57 ` Óscar Fuentes
2014-08-27 23:17 ` Jai Dayal
2014-08-27 23:47 ` Óscar Fuentes
[not found] ` <mailman.7678.1409181490.1147.help-gnu-emacs@gnu.org>
2014-08-28 3:30 ` Rusi
2014-08-28 3:33 ` Jai Dayal
2014-08-28 4:29 ` Óscar Fuentes
[not found] ` <mailman.7693.1409200204.1147.help-gnu-emacs@gnu.org>
2014-08-28 5:39 ` Rusi
2014-08-28 12:27 ` Jai Dayal
[not found] ` <mailman.7714.1409228889.1147.help-gnu-emacs@gnu.org>
2014-08-28 15:53 ` solidius4747
2014-08-28 21:22 ` Óscar Fuentes
2014-08-28 22:24 ` Stefan Monnier
2014-08-28 23:28 ` Dmitry
2014-08-29 0:02 ` Óscar Fuentes
[not found] ` <mailman.7793.1409270604.1147.help-gnu-emacs@gnu.org>
2014-08-29 3:35 ` Stefan Monnier
2014-08-29 6:06 ` David Engster
2014-08-29 13:09 ` Óscar Fuentes
2014-08-29 13:16 ` Jai Dayal
2014-08-29 13:45 ` Óscar Fuentes
2014-08-29 13:52 ` David Engster
2014-08-29 14:16 ` Óscar Fuentes
[not found] ` <mailman.7808.1409292429.1147.help-gnu-emacs@gnu.org>
2014-08-29 13:15 ` Rusi
2014-08-28 17:08 ` Rusi
2014-08-28 17:13 ` Jai Dayal
2014-08-28 19:43 ` Marcin Borkowski
2014-08-28 19:47 ` Jai Dayal
2014-08-28 20:15 ` Marcin Borkowski
[not found] ` <mailman.7743.1409246061.1147.help-gnu-emacs@gnu.org>
2014-08-28 17:26 ` Rusi
2014-08-28 23:01 ` Thorsten Jolitz
2014-08-27 18:45 ` Óscar Fuentes
2014-08-27 14:39 ` Thien-Thi Nguyen
[not found] ` <mailman.7608.1409150189.1147.help-gnu-emacs@gnu.org>
2014-08-27 15:01 ` solidius4747
2014-08-27 18:31 ` Óscar Fuentes [this message]
[not found] <mailman.127014.1409321829.1146.help-gnu-emacs@gnu.org>
2014-08-29 14:33 ` Tory S. Anderson
2014-08-29 17:21 ` Jai Dayal
2014-08-29 18:11 ` Marcin Borkowski
2014-08-29 18:15 ` Jai Dayal
2014-08-29 18:27 ` Marcin Borkowski
2014-08-29 18:34 ` Jai Dayal
2014-08-29 19:17 ` Marcin Borkowski
[not found] ` <mailman.7863.1409335908.1147.help-gnu-emacs@gnu.org>
2014-08-30 3:43 ` Rusi
2014-08-30 7:24 ` Thien-Thi Nguyen
2014-08-30 21:27 ` Jai Dayal
[not found] ` <mailman.7951.1409434065.1147.help-gnu-emacs@gnu.org>
2014-08-31 1:53 ` Rusi
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