Re: [PATCH kvm-unit-tests] cscope: fix database generation

["Radim Krčmář" <rkrcmar@redhat.com>]

2016-04-19 14:58-0400, Bandan Das:
> Radim Krčmář <rkrcmar@redhat.com> writes:
>> 2016-04-19 13:08-0400, Bandan Das:
>>> Andrew Jones <drjones@redhat.com> writes:
>>>> On Mon, Apr 18, 2016 at 07:04:55PM -0400, Bandan Das wrote:
>>>>> 
>>>>> The cscope.files that we generate doesn't include all
>>>>> source files that are potentially interesting. We should
>>>>> include all $(ARCH)es  and not the just the one configure
>>>>> finds. Moreover, $(ARCH) expands to x86_64 which is not the
>>>>> correct path for x86 sources. Generate cscope.files by searching
>>>>> for all files starting from root.
>>>>
>>>> No thanks :-) I'd rather not get hits for x86 and powerpc when
>>> 
>>> I don't think that's a good idea. Just because you don't like to
>>> see x86 bits when jumping around in arm code doesn't mean you should
>>> hide all references to a given function. And if the arm code is
>>> segregated enough that there are no common functions, you won't
>>> see them anyway. 
>>> [...]                                               But please let's
>>> not make it difficult to write arm/powerpc tests just because someone's on
>>> x86 :)
>>
>> In the kernel, environment can override configuration, so you'd do
>>
>>   % ARCH=arm make cscope
>>
>> and it doesn't matter what arch is being compiled.  I think this would
>> be a better solution for kvm-unit-tests too.
>>
>> I agree with Drew that other arches would mostly clutter searches if
>> they were included by default, but we can also add a rule in case
> 
> Since you mentioned the kernel, it looks like both the kernel/qemu
> include all by default which makes sense to me.

qemu does, kernel doesn't (e.g. search for sys_sigreturn).

>                                                 As I mentioned above,
> you definitely don't want to modify a common library function only to
> realize that you forgot to modify all sites. Looking at all sites adds
> visibility, not introduce clutter.
> 
>> indexing all arches is desired (like when changing the prototype of some
>> generic function?).
> 
> kvm-unit-tests is small enough that this can be the default.

I don't see a reason to add results that we'd then have to mentally
filter regardless of their amount.

>                                                              That said, this
> is a trivial change and I am happy to live with it in my local branch. (Unless
> ofcourse both Linux and Qemu decide to make this default behavior too!)

I think we'll agree on something that can be merged -- the present
situation is bad.

For me, "include all" is a matter of `cscope -bk **/*.[chS]` and getting
only arch-specific cscope is harder, so having an option to generate
cscope just for target arch would be nice.

(I don't care about the default much, `ARCH=$sth make cscope` is easy
 to type if the default included all.)