Re: Library dependency files

[Todd Showalter]

On Tue, Apr 27, 2010 at 11:45 AM, Mike Shal <address@hidden> wrote:

>>     All of that said, I've never really noticed significant overhead
>>  from make itself.  Dependency generation is often expensive, but at
>>  least on my projects (even the large ones) all of the time is spent
>>  actually inside the dependency generator.  So it's entirely possible
>>  that it will all be moot.
>
> What do you mean by the "dependency generator" here? Do you have
> something that scans all the source files for their dependencies every
> time you run make? Or do you have them generated as a side-effect of
> compilation like in Philip's case? I think in Philip's setup, after
> everything is built, just running 'make' should parse the Makefiles
> (along with included .d files), then run through the DAG without
> executing anything. No dependency generation would be done, since no
> files are recompiled.

    Typically, my build processes do an upfront dependency generation
sweep (ie: gcc -MM or makedepend or what have you) followed by
compilation.  I've found that (unsurprisingly) on a clean build the
build time is dominated by compilation, while on an incremental build
it is dominated by the depgen sweep.  The depgen sweep is typically
one call with all the source files (ie "makedepend $(SRCS)"), so the
make overhead is minimal.

                                                                        Todd.

-- 
 Todd Showalter, President,
 Electron Jump Games, Inc.