[cfe-dev] C++11 migration tools

[Manuel Klimek]

On Fri, Jun 29, 2012 at 11:45 AM, Chandler Carruth <chandlerc at google.com>wrote:

> I tend to agree that this should use the Tooling/Refactoring stuff.
>
> However, I'm curious about the best way to structure the location of
> migration candidates: AST matchers vs. visitor.
>
> I can almost see the visitor pattern working really well here as each
> different construct can have a pile of migration logic dropped in.... But
> if there is a need to connect dots between more distant constructs, that
> wouldn't work so well.... Not at all sure what would be best here.
>

I've used a combination before - use matchers for the stuff where they work
well, then write a very small easy-to-understand visitor if you need more.
I think that brings down code size by quite a bit - obviously just a gut
feeling here.


>
>
> On Fri, Jun 29, 2012 at 1:37 AM, Manuel Klimek <klimek at google.com> wrote:
>
>> On Fri, Jun 29, 2012 at 4:06 AM, Sam Panzer <panzer at google.com> wrote:
>>
>>> In case anyone wanted to take a look, the attached patch includes the
>>> tool I've been working on. I create a new binary, c++migrate, which
>>> attempts to convert for loops in the source files given to it. Most of my
>>> focus has been on the FrontedAction, so I skirted all of the issues
>>> mentioned above by keeping the frontend interaction minimal (i.e. I just
>>> call Tooling::ClangTool::run), and the changes are just reported on
>>> standard output, if there are any to be made.
>>>
>>> The tool can currently convert for loops that range over (1) statically
>>> allocated arrays, and (2) Clang-style iterator-based loops (with begin and
>>> end iterators defined). All loop variables need to be declared within the
>>> loop's initialization step in order for it to be converted, though this
>>> requirement can potentially be eliminated. I'm working on converting
>>> iterator-based loops that call someContainer.end() on each iteration, since
>>> they're probably the common case in many codebases.
>>>
>>> Just for fun, I ran the tool over the 41 .cpp files in lib/Sema, and my
>>> tool found 71 convertible loops in 17 files. There is plenty more work to
>>> go, because it clearly missed some easy ones.
>>>
>>> Any input or feedback is welcome!
>>>
>>
>> High-level observations:
>> 1. the handling of the rewrites; any reason not to use the
>> Tooling/Refactoring stuff? Currently in the patch it looks to me like the
>> files are not rewritten, but dumped to stdout
>> 2. is the reason not to use the matchers here that they're not landed in
>> mainline yet?
>>
>> Cheers,
>> /Manuel
>>
>>
>>>
>>> -Sam
>>>
>>> On Thu, Jun 28, 2012 at 10:50 AM, Sam Panzer <panzer at google.com> wrote:
>>>
>>>> I'm that intern :)
>>>>
>>>> -Sam
>>>>
>>>>
>>>> On Wed, Jun 27, 2012 at 9:48 PM, John Wiegley <johnw at boostpro.com>wrote:
>>>>
>>>>> >>>>> Sam Panzer <panzer at google.com> writes:
>>>>>
>>>>> > In particular, I am working on a tool to convert existing C++ for
>>>>> loops to
>>>>> > take advantage of the new C++11 range-based syntax. I can imagine
>>>>> similar
>>>>> > tools to replace const with constexpr, macro hacks with
>>>>> static_assert, and
>>>>> > potentially other common refactorings.
>>>>>
>>>>> > Thoughts? Suggestions?
>>>>>
>>>>> You really must watch this presentation, if you haven't already:
>>>>>
>>>>>     http://www.youtube.com/watch?v=yuIOGfcOH0k
>>>>>
>>>>> --
>>>>> John Wiegley
>>>>> BoostPro Computing
>>>>> http://www.boostpro.com
>>>>> _______________________________________________
>>>>> cfe-dev mailing list
>>>>> cfe-dev at cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>>>>
>>>>
>>>>
>>>
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>>>
>>
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>
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