Re: [RFA 0/5] Some random C++-ification

[Pedro Alves <palves@redhat.com>]

On 09/22/2016 06:50 PM, Tom Tromey wrote:
> I was feeling inspired by Pedro's Cauldron slides, so I found a few

Awesome!  :-)

> random spots that could be converted from cleanups to self-managing
> data structures from libstdc++ -- in these cases, std::string and
> std::vector.
> 
> I saw a note in one of the C++ conversion documents about perhaps not
> using std::vector, since GCC did not.  However, I think often GCC's
> uses are unusual, and I don't think there is any reason to avoid
> std::vector in (most of) gdb.

Agreed.

> 
> This should probably not go in until after Pedro's "new" patch.

Does that patch look OK to you?

> 
> Built and regtested on x86-64 Fedora 24.
> 
> A few reflections on these changes:
> 
> * First, I think it's a nice improvement.  The examples here aren't so
>   dramatic, but if you dig a bit it's easy to find cases where the
>   cleanup logic is complicated; and this approach eventually lets one
>   delegate all that work to the compiler.

Agreed.

> 
> * Speaking of, I have a patch to convert uses of the ensure_python_env
>   to use RAII.  However, I don't think this is ready to go in --
>   because the cleanups installed by this are order-sensitive with
>   respect to other cleanups that might be created in the various
>   Python-calling functions.  My belief is that cleanups have to all be
>   run before any destructors, so any ordering issues are a subtlety
>   that, in the short term, will have to be accounted for in code
>   review.
> 
> * It wasn't actually clear to me that this kind of change is
>   desirable.

I think it is.  We need to eliminate _all_ cleanups in order to
get rid of the TRY/CATCH macros...  I think there's a lot of
value in getting the codebase rid of the C -> C++ partial
transition and inviting to work on.

> 
> * I was unclear on the coding style to use so I just used the gdb C
>   style.  Maybe there are some spaces that shouldn't be there now.

Looked fine to me.

Thanks,
Pedro Alves