On 27.08.2013 15:34, Frantisek Hrbata wrote: > On Mon, Aug 26, 2013 at 04:14:07PM +0200, Peter Oberparleiter wrote: >> On 24.08.2013 21:44, Frantisek Hrbata wrote: >>> On Fri, Aug 23, 2013 at 05:21:12PM +0200, Peter Oberparleiter wrote: >>>> On 23.08.2013 17:15, Peter Oberparleiter wrote: >>>>> On 23.08.2013 10:39, Frantisek Hrbata wrote: >>>>>> Compile the correct gcov implementation file for a specific gcc version. In >>>>>> the future, if another file is added, the conditions will need to be somehow >>>>>> adjusted to if-elif-else case, but at this point the simple cc-ifversion should >>>>>> be enough. >>>> >>>> As promised, I'm also adding the patch that makes the format-specific part >>>> of gcov-kernel a loadable kernel module: >>>> >>>> --- >>>> kernel: gcov: make format-specific code loadable >>>> >>>> Turn the format-specific part of gcov-kernel into a loadable kernel >>>> module. This enables the use of gcov-kernel with kernel modules >>>> that were compiled with a version of GCC that produces a different >>>> gcov format when compared to the version of GCC that was used to >>>> compile the kernel. >>> >>> If I understand it correctly, this would mean that you will be able to use only >>> one implementation of gcov format at the time. Meaning you will be able to get >>> coverage data for module, but not for kernel if it was compiled with different >>> gcc(gcda format). This is probably ok if you work only on your module, but I'm >>> not sure this is generally the right approach. In this case I would probably >>> rather see some support for more gcov formats at the same time(e.g. set of >>> callback operations per gcov version). Again I'm probably missing something, but >>> I still cannot see reason why to add such feature. If you want gcov support just >>> compile your kernel and modules with the same gcc version(gcda format). But if >>> this is really needed maybe it would be better to consider some parallel support >>> for more gcov formats based on the gcov_info version. >> >> The callback approach has other drawbacks (see previous mail). > > Agreed, I did not realized these problems for the first time when I was thinking > about the callback approach. > >> >>> Would it be possible to add support for the modified gcc 4.7 gcov format and >>> deal with this later? I can incorporate your changes: iter to use buffer, >>> .init_array for modules and possibility to explicitly select the gcda format. >>> In this case we will have at least the basic support in kernel. This is just me >>> thinking out loud. >> >> I think that's an approach I can live with. Maybe the need for a multi-version >> support will surface again later in a more refined form, but until then there >> should be no reason to delay base GCC 4.7 support any further. > > Great. I can incorporate the changes you proposed and post V2. Or do you prefer > to post it by your self? Based on the info and patches you already provided I > guess you already have something ready. Simply what suits you best :). If it's not too much hassle, I'd prefer that you post V2 of your patches. Also I guess it would make sense to put Andrew Morton on CC since the initial gcov-patches were picked up by him. -- Peter Oberparleiter Linux on System z Development - IBM Germany -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
