[petsc-dev] Issue with dependency generation in GCC 9

[Matthew Knepley]

On Mon, Jan 20, 2020 at 9:58 AM Lisandro Dalcin <dalcinl at gmail.com> wrote:

> On Mon, 20 Jan 2020 at 17:07, Jed Brown <jed at jedbrown.org> wrote:
>
>> From my man page (contradicting the behavior Lisandro observed):
>>
>>    -MD -MD is equivalent to -M -MF file, except that -E is not implied.
>> The driver
>>        determines file based on whether an -o option is given.  If it is,
>> the driver uses
>>        its argument but with a suffix of .d, otherwise it takes the name
>> of the input
>>        file, removes any directory components and suffix, and applies a
>> .d suffix.
>>
>>
>> Lisandro, what does your man page say?
>>
>
> It says exactly the same. But you are confusing the flag, -MF is about
> naming the output dep filename, i.e. ompi-optg/obj/sys/objects/init.d in
> your example, that is just fine, I do get that file with that name.
> My issue is with the contents GCC writes within that dep file,
> specifically the TARGET, which can be specified with -MT, but it is
> cumbersome to do, unless you use "-MT $@", though no idea how to update
> configure for that.
>

Here is the test:


https://gitlab.com/petsc/petsc/blob/master/config/BuildSystem/config/compilers.py#L1345

We need to update it to break with your compiler, and then add another line
with the -MT.

  Thanks,

     Matt


> --
> Lisandro Dalcin
> ============
> Research Scientist
> Extreme Computing Research Center (ECRC)
> King Abdullah University of Science and Technology (KAUST)
> http://ecrc.kaust.edu.sa/
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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