Re: A flaw in dep generation with gcc -MMD?

Hi,

(restoring cc list.  Unfortunately gmane's web interface doesn't
 provide a built-in way to reply-to-all.  [1] has a hackish
 workaround.)
Samuel Bronson wrote:

Nguyen Thai Ngoc Duy writes:

quoted

"gcc -MF depfile -MMD -MP -c -o path/to/file.o" will produce "depfile"
with target given by "-o". When ccache runs, it executes "gcc -MF
depfile -MMD -MP -E" instead to get the final content for hashing.
Notice that "-c -o" combination is replaced by "-E". The latter
produces target without leading path.

[...]

I'm pretty sure you should report this against ccache; GCC seems to be
behaving as documented.

Seems to have been fixed by v3.0pre0~187:

 commit e8354384
 Author: Andrea Bittau [off-list ref]
 Date:   Sun Nov 1 19:39:58 2009 +0100

     Fix handling of the -MD and -MDD options

     From <http://lists.samba.org/archive/ccache/2007q2/000272.html>:

     The -MD and -MDD options automatically determine where the dependency file
     should land and what the target should look like based on the -o option.
     However, ccache drops -o and things mess up. The original patch was posted by
     Kaz Kylheku but I reworked it to make it work properly. Here is his post:

     http://lists.samba.org/archive/ccache/2006q4/000249.html

Workaround incoming in a few moments.

Thanks,
Jonathan