[LLVMdev] compiler-rt CMake build ignores CMAKE_CXX_FLAGS

[Alexey Samsonov]

On Mon, Mar 24, 2014 at 2:09 PM, Dmitri Gribenko <gribozavr at gmail.com>wrote:

> On Mon, Mar 24, 2014 at 9:49 AM, Alexey Samsonov <samsonov at google.com>
> wrote:
> > Submitted r204593.
>
> Thank you!  It did fix compiling the tests on the buildbot, but I am
> surprised that linking succeeded.  Maybe that is because we are not
> using any C++11 features that require symbols from the newer
> libstdc++.  But it would be future-proof to change clang_link_shared()
> to use CMAKE_CXX_FLAGS as well.
>

Is there really a logic in Clang that would choose between old and newer
libstdc++ versions
depending on the value of -std= flag?

I hope to get rid of clang_compile and clang_link_shared horridness soon by
switching
to LLVM_BUILD_EXTERNAL_COMPILER_RT=ON that would use just-built Clang to
configure/build compiler-rt.

So, your use case might be interesting. Can you build with
-DLLVM_BUILD_EXTERNAL_COMPILER_RT=ON and
check if "make check-compiler-rt" works for you? If not, then we'd have to
propagate *some* CMAKE_CXX_FLAGS
to configuration step of compiler-rt project, but we won't need most of the
extra flags stuffed into CMAKE_CXX_FLAGS
by LLVM/Clang CMake files. It might be a problem (sigh).


>
> Dmitri
>
> --
> main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
> (j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
>



-- 
Alexey Samsonov, MSK
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