bug#8880: depcomp for Portland Group Compilers: get rid of file locking hack?

[Dave Goodell]

On Jul 12, 2012, at 3:43 PM CDT, Stefano Lattarini wrote:

> Reading the documentation provided here:
> 
>  <http://www.pgroup.com/doc/pgiref.pdf>
> 
> I see that the the '-MD' option should also accept an argument:
> 
>  -MD,filename  (pgcpp only) Generate make dependence lists and print
>                             them to file filename.
> 
> maybe we could we use this to get rid of the need of the horrid file-locking
> hack -- explained in this comments from depcomp:
> 
>  # For projects that build the same source file twice into different object
>  # files, the pgcc approach of using the *source* file root name can cause
>  # problems in parallel builds.  Use a locking strategy to avoid stomping on
>  # the same $tmpdepfile.
> 
> In particular, I propose the attached patch.  Can you give it a try to check
> whether it works?

I'm currently in the process of running the test suite with the given patch, 
but it almost certainly doesn't work with the PGI 10.x compilers that I have 
handy.  I just tried a manual test of the compiler with "-MD,asdf.d" and it 
didn't complain but it also did not generate the expected dependency file.

Also, it appears that this switch is "pgcpp only", even in the newer version to 
which this manual refers.  Depcomp doesn't know how to switch to using the 
preprocessor instead of the compiler, right?

There's a comment bug in the patch, too.  "-MF" should read "-MD".

-Dave