[PATCH] Fix few build warnings with LLVM toolchain

[Richard Sandiford]

Segher Boessenkool <segher@kernel.crashing.org> writes:
> On Fri, Jun 28, 2019 at 08:55:00AM -0600, Martin Sebor wrote:
>> Jeff reminded me in a code review the other day that GCC does
>> have a guideline for defining POD structs with the keyword
>> "struct" and classes with ctors/dtors using "class":
>> 
>>   https://gcc.gnu.org/codingconventions.html#Struct_Use
>> 
>> I quickly prototyped a warning to see how closely GCC follows
>> this convention.  The result shows that out of just under 800
>> structs and classes defined in GCC sources some 200 use
>> the keyword 'struct' despite having a ctor or dtor, or about
>> 25%.  So as is the case with most other conventions, without
>> a tool to help remind us they exist they are unlikely to be
>> followed with enough consistency to be worth putting in place
>> to begin with.
>
> The goal is not to have the rules adhered to.  The goal is to have
> a more readable / maintainable / etc. codebase.

IMO it's a shame we don't follow that attitude for changelogs,
where apparently the number of spaces between the name and the email
address is of vital importance :-)  Too often a new contributor's
first taste of GCC is a slew of comments about things like that.

But surely it's a valid point that we're not following our own
conventions on the C++ usage.  I miss how consistent the codebase
was in the C days...

That can be fixed by changing the conventions if we no longer think
they're a good idea.  But if someone's willing to change the codebase
to follow (one of) the coventions instead, and willing to add a warning
to keep things that way, then that sounds like a really good thing.
Especially when it's a common convention that others might want a
warning for too.

And I don't think the current state of the struct/class tags is really
a result of making the codebase more maintainable.  I get the feeling
it just kind-of happened.  ISTM we're trying too hard to find a reason
not to clean this up.

(Just replying because I know Martin has been on the receiving end of a
lot of review comments about patches that didn't follow the conventions.
Not necessarily any more than anyone else, and from what I remember
the comments were accurate.  But after all that, I don't think it's fair
to say that the conventions don't really matter.)

Thanks,
Richard