[cfe-dev] On the preferred use of C++ in the clang source code

[Chris Lattner]

>> It is pretty subjective.  We do use almost all C++ features  
>> somewhere in the (greater llvm) code base.  It's really more about  
>> making clear and simple code than it is about banning specific  
>> language features.  Some coding guidelines are available here:
>> http://llvm.org/docs/CodingStandards.html
>
> Bookmarked; thanks!
>
> Note, the reference to "Effective C++" at the bottom is a little  
> out of date; the third edition was published two years ago and  
> contains some significant changes:
>
> http://tinyurl.com/26gch4
>
> Also the other two links (for the strings "available as well" and  
> "Large-Scale C++ Software Design" appear to be broken.

Thanks, fixed!

>> That said, there are two features we don't like:  RTTI and EH.   
>> This is because they violate the "don't pay for it if you don't  
>> use it" principle.  If building with GCC, clang disables both RTTI  
>> and EH support (-fno-rtti and -fno-exceptions).  The main llvm  
>> repository has a couple of places that still use RTTI, but we'd  
>> like to fix that.
>>
>> The main problem with RTTI and EH is the impact on binary size.   
>> Many clients of LLVM and at least one client of clang use them in  
>> a JIT context.  Having the binaries be as small as possible makes  
>> it easier for people to distribute them with their apps.
>
> I think that may be the least-flaky objection to EH that I've heard  
> so far.  (:

:)

It is actually really frustrating, because certain pieces of the  
compiler (e.g. error recovery in the parser) could be slightly  
cleaner with exceptions.

-Chris