[FFmpeg-devel] [RFC] Hack to disable implicit rules

[Ramiro Polla]

On Tue, Feb 16, 2010 at 5:53 PM, Reimar D?ffinger
<Reimar.Doeffinger at gmx.de> wrote:
> On Tue, Feb 16, 2010 at 07:45:13PM +0000, M?ns Rullg?rd wrote:
>> Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:
>> > On Tue, Feb 16, 2010 at 09:43:34AM +0000, M?ns Rullg?rd wrote:
>> >> Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:
>> >>
>> >> > Hello,
>> >> > since I've only recently seen them causing issues (mostly due to MinGW and
>> >> > Cygwin make being broken most of the time) and found a way that seems
>> >> > to disable them (although maybe more as a side-effect), I'd like to propose
>> >> > this patch.
>> >> > What are your opinions?
>> >> > Index: common.mak
>> >> > ===================================================================
>> >> > --- common.mak ? (revision 21840)
>> >> > +++ common.mak ? (working copy)
>> >> > @@ -4,6 +4,10 @@
>> >> >
>> >> > ?all: # make "all" default target
>> >> >
>> >> > +# disable suffix rules, we do not use them and like this we avoid (most?)
>> >> > +# implicit rules which might cause slowdowns or bugs
>> >> > +.SUFFIXES:
>> >> > +
>> >>
>> >> Does this fix an actual problem?
>> >
>> > Not for FFmpeg, no.
>>
>> Then it serves no purpose. ?Code (in the broader sense) without a
>> purpose does not belong in FFmpeg.
>
> Just thought I remembered someone saying they'd prefer to get rid of the
> implicit rules stuff, maybe also because they slow down compilation on Windows
> (I don't know if it really makes a significant difference).

$ time make
make: Nothing to be done for `all'.

real    0m21.800s
user    0m6.589s
sys     0m14.580s

$ time make -r
make: Nothing to be done for `all'.

real    0m1.783s
user    0m0.460s
sys     0m1.131s

With patch
$ time make
make: Nothing to be done for `all'.

real    0m4.636s
user    0m1.201s
sys     0m2.914s