llvm dev - Jun 2017 - Failed to build libunwind the libcxx's __config header

I'm building LLVM with Clang, LLD, compiler-rt, libunwind, libcxx and
libcxxabi.

I'm using GCC 7.1.1 and binutils 2.28.0 to build.

The compilation is aborted during libunwind build due to gcc not being able to
parse libcxx's __config:

    /usr/bin/cc -DLLVM_BUILD_GLOBAL_ISEL -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS
-D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Iprojects/libunwind/src
-I../projects/libunwind/src -Iinclude -I../include
-I../projects/libunwind/include -I../projects/libcxx/include -fPIC
-Werror=date-time -Wall -W -Wno-unused-parameter -Wwrite-strings
-Wno-missing-field-initializers -pedantic -Wno-long-long -Wno-comment
-ffunction-sections -fdata-sections -O3 -DNDEBUG   -Werror=return-type -W -Wall
-Wchar-subscripts -Wconversion -Wmissing-braces -Wno-unused-function -Wshadow
-Wsign-compare -Wsign-conversion -Wstrict-aliasing=2 -Wstrict-overflow=4
-Wunused-parameter -Wunused-variable -Wwrite-strings -Wundef -Wno-error
-pedantic -D_DEBUG -UNDEBUG -D_LIBUNWIND_IS_NATIVE_ONLY -fPIC -fno-exceptions
-funwind-tables -std=c99  -fPIC -Werror=date-time -Wall -W -Wno-unused-parameter
-Wwrite-strings -Wno-missing-field-initializers -pedantic -Wno-long-long
-Wno-comment -ffunction-sections -fdata-sections -funwind-tables -MD -MT
projects/libunwind/src/CMakeFiles/unwind_objects.dir/UnwindLevel1.c.o -MF
projects/libunwind/src/CMakeFiles/unwind_objects.dir/UnwindLevel1.c.o.d -o
projects/libunwind/src/CMakeFiles/unwind_objects.dir/UnwindLevel1.c.o   -c
../projects/libunwind/src/UnwindLevel1.c
    In file included from ../projects/libcxx/include/inttypes.h:234:0,
                     from ../projects/libunwind/src/UnwindLevel1.c:22:
    ../projects/libcxx/include/__config:1140:18: error: missing binary operator
before token "("
         __has_feature(attribute_availability_with_strict) &&           
\
                      ^
The exact line that fails:
https://github.com/llvm-mirror/libcxx/blob/master/include/__config#L1140

Does anyone else have this problem? What can possibly cause such error?

Regards,
Dmitry

Hi Dmitry,

On 2 June 2017 at 07:49, Dmitry Golovin via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> Does anyone else have this problem? What can possibly cause such error?
G++ doesn't support __has_feature, so it should be picking up the
default "#define __has_feature(__x) 0" further up in __config. The
preprocessed output (via "-E -dD") would be interesting to diagnose
the issue, if no-one else has seen it before.

Cheers.

Tim.

Hi Tim,

You can find the preprocessed UnwindLevel1.c and UnwindLevel1-gcc-ext.c
attached.

Regards,
Dmitry

02.06.2017, 18:06, "Tim Northover" <t.p.northover at
gmail.com>:
> Hi Dmitry,
>
> On 2 June 2017 at 07:49, Dmitry Golovin via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>>  Does anyone else have this problem? What can possibly cause such
error?
>
> G++ doesn't support __has_feature, so it should be picking up the
> default "#define __has_feature(__x) 0" further up in __config.
The
> preprocessed output (via "-E -dD") would be interesting to
diagnose
> the issue, if no-one else has seen it before.
>
> Cheers.
>
> Tim.
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Hi Tim,

You can find the preprocessed UnwindLevel1.c and UnwindLevel1-gcc-ext.c
attached.

I first sent it without compression, so it turned out to be over 100Kb and
should be approved first before it can make to the mailing list, so I gzipped
the files. Expect to get a duplicate of this message when the first copy gets
its approval.

Regards,
Dmitry

02.06.2017, 18:06, "Tim Northover" <t.p.northover at
gmail.com>:
> Hi Dmitry,
>
> On 2 June 2017 at 07:49, Dmitry Golovin via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>>  Does anyone else have this problem? What can possibly cause such
error?
>
> G++ doesn't support __has_feature, so it should be picking up the
> default "#define __has_feature(__x) 0" further up in __config.
The
> preprocessed output (via "-E -dD") would be interesting to
diagnose
> the issue, if no-one else has seen it before.
>
> Cheers.
>
> Tim.
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