[llvm-dev] Compilation errors

[Arno Bastenhof via llvm-dev]

As an aside, is there any reason for why C++-style comments were used
in C files at all, or should they simply be replaced with the usual /*
... */ in accordance with pre-C99 standards? In the latter case, would
there be any objection to it if I were to make a patch for this? While
the change itself would be trivial, I don't yet have any experience
with making patches, and so for that purpose it would be a useful
exercise.

Note that in my previous reply I assumed the use of CMake. I did see
there's already a couple of Makefiles in the source tree as well, but
I remember having read somewhere these haven't been touched in a long
time and the use of CMake was the preferred method for generating
Makefiles now. (But again, correct me if I'm wrong.)

On 12/1/15, Arno Bastenhof <arnobastenhof at gmail.com> wrote:
> Disclaimer: coming from a Java background where tools like Ant, Maven
> and Gradle reign supreme, I'm rather new to make and CMake myself (not
> to mention C and C++, which I've only started learning recently). So
> take my words with a grain of salt. Nonetheless, you'll find my take
> below:
>
> The relevant lines, I would suppose, are
>
> error: C++ style comments are not allowed in ISO C90 [-Werror]
>  #endif // defined(_MSC_VER) && !defined(__clang__)
>
> and
>
> error: (this will be reported only once per input file) [-Werror]
> cc1: all warnings being treated as errors
>
> So, did you happen to have generated your make files using CMake
> passing -DLLVM_ENABLE_WERROR=ON ?
>
> My reasoning is as follows (but please do correct me if I'm wrong
> somewhere): When generating your make file using cmake, since by
> default LLVM_ENABLE_PEDANTIC is set to ON, the above warning gets
> triggered (cf. the description of "pedantic" at
> https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html, assuming that
> either you're building with gcc, or that Clang has the same
> interpretation of "pedantic"). Again, by default, LLVM_ENABLE_WERROR
> is set to OFF, so it should normally remain a warning.
>
> On 12/1/15, Peter Teoh via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>> While doing a make on the recently checkout version:
>>
>> I got the following errors:
>>
>> [ 68%] Built target dd
>> [ 68%] Built target compiler-rt-headers
>> [ 68%] Building C object
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-x86_64.dir/x86_64/floatdidf.c.o
>> In file included from
>> /home/tthtlc/llvm/llvm/projects/compiler-rt/lib/builtins/x86_64/floatdidf.c:9:0:
>> /home/tthtlc/llvm/llvm/projects/compiler-rt/lib/builtins/x86_64/../int_lib.h:131:8:
>> error: C++ style comments are not allowed in ISO C90 [-Werror]
>>  #endif // defined(_MSC_VER) && !defined(__clang__)
>>         ^
>> /home/tthtlc/llvm/llvm/projects/compiler-rt/lib/builtins/x86_64/../int_lib.h:131:8:
>> error: (this will be reported only once per input file) [-Werror]
>> cc1: all warnings being treated as errors
>> make[2]: ***
>> [projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-x86_64.dir/x86_64/floatdidf.c.o]
>> Error 1
>> make[1]: ***
>> [projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-x86_64.dir/all]
>> Error 2
>> make: *** [all] Error 2
>>
>> Can anyone comment on the error?
>>
>> --
>> Regards,
>> Peter Teoh
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>