[cfe-dev] Fiddling the Rewriter tests (anyone still care about Objective-C/C++?)

[Robinson, Paul via cfe-dev]

> -----Original Message-----
> From: Nat! [mailto:nat at mulle-kybernetik.com]
> Sent: Thursday, December 08, 2016 1:31 AM
> To: Robinson, Paul
> Cc: cfe-dev at lists.llvm.org
> Subject: Re: [cfe-dev] Fiddling the Rewriter tests (anyone still care
> about Objective-C/C++?)
> 
> Robinson, Paul via cfe-dev schrieb:
> > Privately, we set the default C++ dialect to C++11.  This causes all
> > kinds of fun with the Clang tests, and Charles Li has been doing a lot
> > of work to make the tests able to tolerate C++11.  I'm helping out a
> > little bit.
> >
> > Specifically I'm looking at the Rewriter tests.  It looks like these
> > take Objective-C/C++ input, generate a non-Objective equivalent, and
> > then compile the resulting C++ to make sure it's clean.  There are
> > 32 tests that fail in the "compile the resulting C++" stage, when we
> > set the default dialect to C++11.
> >
> > I'm guessing that Objective-C/C++ is kind of passe, so nobody is really
> > interested in modernizing it (or the C++ that the rewriter produces).
> > Therefore I'm proposing to simply add '-std=gnu++98' to the failing
> tests,
> > and be done with it.
> >
> > Anybody mind if I do this?
> > Thanks,
> > --paulr
> >
> 
> Hi Paul
> 
> 
> If you look at "lib/Frontend/CompilerInvocation.cpp#1531" or so, you
> will see that the language set for most ObjC runtimes is gnu++98.
> 
>     case IK_CXX:
>     case IK_PreprocessedCXX:
>     case IK_ObjCXX:
>     case IK_PreprocessedObjCXX:
>       LangStd = LangStandard::lang_gnucxx98;
>       break;
> 
> So if the test somehow ignore this, then -std=gnu++98' sounds sensible
> to me. Hope this helps. I myself have never used the Rewriter.

Hi Nat!  What we do privately is something like this:

    case IK_CXX:
    case IK_PreprocessedCXX:
      LangStd = LangStandard::lang_cxx11;
      break;
    case IK_ObjCXX:
    case IK_PreprocessedObjCXX:
      LangStd = LangStandard::lang_gnucxx98;
      break;


The tests I am looking at all do something like this:

RUN: %clang_cc1 -x objective-c++ ... %s -o %t.cpp
RUN: %clang_cc1 -fsyntax-only ... %t.cpp

That is, rewrite the objective-c++ source, then compile the result.

So, the objective-c++ part is implicitly compiled with -std=gnu++98, 
but then (for me) the C++ part is implicitly compiled -std=c++11.
What I am doing is adding -std=gnu++98 to the C++ part.

Thanks,
--paulr

> 
> Ciao
>    Nat!
> 
>