[ccache] Generated dep file newer than object file

[Andrew Gallagher]

On Sun, May 1, 2011 at 2:27 PM, Joel Rosdahl <joel at rosdahl.net> wrote:
> On 2011-05-01 23:02, Andrew Gallagher wrote:
>> [...]
>> foo.o: foo.c
>>   gcc -c -MD ...
>>
>> foo.o: foo.d
>
> .d files aren't supposed to be dependencies, so I'd argue that such a
> Makefile is badly written.

I am not too familiar with combining generated dep files and
makefiles, but I suppose this has more to do with making 'ccache' more
compliant with the expected behavior of 'gcc'.  That said, I couldn't
find anywhere where it says that 'gcc -MD' should generate dep files
with an mtime <= the mtime of the object file.  This is just the
behavior I've observed.

>> I think the fix is pretty simple (I've been adding an
>> "update_mtime(output_obj);" if a dep file is produce). What would be
>> the best way to send diffs/patches for bug fixes like this?
>
> You can either send the patch to this list or create a bug report; see
> <http://ccache.samba.org/bugs.html>.

Ok cool, I'll send a patch shortly.

Thanks,
Andrew