Re: PATCH PING: distcc and ccache speedup: adds directives-only preprocessing

[Mark Mitchell <mark at codesourcery dot com>]

Ollie Wild wrote:

> This option provides a simplified preprocessor that improves the
> performance of applications such as ccache and distcc.  In both these
> cases,
> usage is straightforward:
> 
> @smallexample
> distcc /usr/bin/gcc -fdirectives-only [COMPILER OPTIONS]
> @end smallexample

I would replace all of what's quoted above with:

  When preprocessing, handle directives, but do not expand macros.

I don't think the distcc and/or ccache references are appropriate here.
 (The manuals for those tools could be updated to reference this option,
of course.)  If we're going to say more in the GCC manual, it should be
more motivational, like:

  If you need to determine whether two files will be the same after
preprocessing, you can use this option to generate preprocessed source
for comparison.  If the two files are identical after being preprocessed
with @option{-fdirectives-only}, they will also be the same after full
preprocessing.  This option is substantially faster that full preprocessing.

Feel free to add that, if you like.

The patch is OK with those changes.

Thanks,

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713