[llvm] r201679 - Disable override and final C++ keyword in gcc 4.6.

[Logan Chien]

Hi Gordon,

I am using autoconf.  I can build without problem with following commands:

$ export CXXFLAGS=-std=c++0x
$ ./configure --enable-optimized --disable-compiler-version-checks
$ make -j4
$ make check-all

The revision which I am using are LLVM/r201841, clang/r201849, and
compiler-rt/r201845.

The gcc version I am using is:

$ gcc --version
gcc-4.6.real (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3

Sincerely,
Logan


On Fri, Feb 21, 2014 at 2:45 AM, Gordon Keiser <gkeiser at arxan.com> wrote:

> I pulled down trunk on Tuesday night, and it errors in CMake on linux if
> GCC < 4.7, so I'm not really sure what purpose this serves.
>
>
>
> -Gordon
>
>
>
> *From:* llvm-commits-bounces at cs.uiuc.edu [mailto:
> llvm-commits-bounces at cs.uiuc.edu] *On Behalf Of *Logan Chien
> *Sent:* Wednesday, February 19, 2014 12:11 PM
> *To:* Aaron Ballman
> *Cc:* llvm-commits
> *Subject:* Re: [llvm] r201679 - Disable override and final C++ keyword in
> gcc 4.6.
>
>
>
> Hi Aaron,
>
> I know that GCC 4.7 is the minimum support compiler.  However, since the
> change is limited to the compiler compatibility header (there are even some
> checks for GCC 3.1 in this header) and this change fixes the build and
> passes all test cases, I feel it is acceptable in this case.
>
> Although I know the code base might be incompatible with GCC 4.6 in the
> near future, I wish to keep the backward compatibility as long as possible
> given that only some simple change to compiler compatibility header is
> required.  I agree that it won't make sense to stick with old syntax or
> prohibit the usage of new language feature just for the backward
> compatibility of the unsupported GCC 4.6.
>
> Sincerely,
>
> Logan
>
>
>
> On Wed, Feb 19, 2014 at 11:27 PM, Aaron Ballman <aaron at aaronballman.com>
> wrote:
>
> Since our min supported compiler version is 4.7 (as of llvm 3.4), I
> don't believe this commit really makes sense. Since we're trying to
> make the switch to using C++11 functionality, I don't think we want to
> add support for older compilers which will fail in other ways.
>
> ~Aaron
>
>
> On Wed, Feb 19, 2014 at 10:04 AM, Logan Chien <tzuhsiang.chien at gmail.com>
> wrote:
> > Author: logan
> > Date: Wed Feb 19 09:04:29 2014
> > New Revision: 201679
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=201679&view=rev
> > Log:
> > Disable override and final C++ keyword in gcc 4.6.
> >
> > According to http://gcc.gnu.org/projects/cxx0x.html,
> > override and final keyword was added in gcc 4.7.  Thus,
> > we should not use these keywords in gcc 4.6 even when
> > __GXX_EXPERIMENTAL_CXX0X__ is available.
> >
> > Modified:
> >     llvm/trunk/include/llvm/Support/Compiler.h
> >
> > Modified: llvm/trunk/include/llvm/Support/Compiler.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compiler.h?rev=201679&r1=201678&r2=201679&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/include/llvm/Support/Compiler.h (original)
> > +++ llvm/trunk/include/llvm/Support/Compiler.h Wed Feb 19 09:04:29 2014
> > @@ -152,7 +152,8 @@
> >  /// LLVM_FINAL - Expands to 'final' if the compiler supports it.
> >  /// Use to mark classes or virtual methods as final.
> >  #if __has_feature(cxx_override_control) || \
> > -    defined(__GXX_EXPERIMENTAL_CXX0X__) || LLVM_MSC_PREREQ(1700)
> > +    (defined(__GXX_EXPERIMENTAL_CXX0X__) && __GNUC_PREREQ(4, 7)) || \
> > +    LLVM_MSC_PREREQ(1700)
> >  #define LLVM_FINAL final
> >  #else
> >  #define LLVM_FINAL
> > @@ -161,7 +162,8 @@
> >  /// LLVM_OVERRIDE - Expands to 'override' if the compiler supports it.
> >  /// Use to mark virtual methods as overriding a base class method.
> >  #if __has_feature(cxx_override_control) || \
> > -    defined(__GXX_EXPERIMENTAL_CXX0X__) || LLVM_MSC_PREREQ(1700)
> > +    (defined(__GXX_EXPERIMENTAL_CXX0X__) && __GNUC_PREREQ(4, 7)) || \
> > +    LLVM_MSC_PREREQ(1700)
> >  #define LLVM_OVERRIDE override
> >  #else
> >  #define LLVM_OVERRIDE
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140221/8cf08a3d/attachment.html>