[llvm-dev] Building SVN head with CMake - shared libraries?

[Ismail Donmez via llvm-dev]

On Sat, Jan 16, 2016 at 9:33 PM, Dan Liew <dan at su-root.co.uk> wrote:
>> I am trying to enable this on openSUSE but it seems to break
>> standalone lldb (note that we don't ship static libs):
>>
>> cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
>> -DCMAKE_CXX_FLAGS=-stdlib=libc++ -DLLVM_BUILD_LLVM_DYLI
>> B=ON -DLLVM_LINK_LLVM_DYLIB=ON -DCMAKE_INSTALL_PREFIX=/usr
>> -DCMAKE_BUILD_TYPE=RelWithDebInfo -DLLVM_LIBDIR_SUFFIX=64 -DLLDB_PA
>> TH_TO_LLVM_BUILD=/usr -DLLDB_PATH_TO_CLANG_BUILD=/usr
>> -DLLVM_RUNTIME_OUTPUT_INTDIR=/home/abuild/rpmbuild/BUILD/lldb-3.8.0/buil
>> d/bin -DLLVM_LIBRARY_OUTPUT_INTDIR=/home/abuild/rpmbuild/BUILD/lldb-3.8.0/build/lib64
>> -DPYTHON_VERSION_MAJOR=2 -DPYTHON_VERSIO
>> N_MINOR=7 -G Ninja ..
>>
>> [...]
>>
>> CMake Error at /usr/share/llvm/cmake/LLVMExports.cmake:1011 (message):
>>   The imported target "LLVMSupport" references the file
>>
>>       "/usr/lib64/libLLVMSupport.a"
>
> Could you try appending ``-DLLVM_LINK_LLVM_DYLIB=ON`` to your CMake
> invocation? It looks like lldb is using the ``llvm_add_library()``
> function in the ``cmake/modules/AddLLVM.cmake`` (LLVM source tree)
> which uses ``LLVM_LINK_LLVM_DYLIB`` (and a few other variables) to
> decide whether to link against LLVM's static component libraries or
> the monolithic shared library. I could be wrong on this though but it
> should
> be pretty quick to check.

I already use  -DLLVM_BUILD_LLVM_DYLIB=ON  -DLLVM_LINK_LLVM_DYLIB=ON

> Out of curiosity though if you're building packages on openSUSE why do
> you need a standalone build? I thought the normal way to do this was
> to build everything and then generate split packages?

Nice question. Since Mesa depends on llvm and Mesa is very crucial to
a distro bootstrap, adding any new dependency to llvm creates a
circular dependency which we can't have. And lldb itself brings python
dependency which complicates the issue (python has a Mesa dependency).
I may try to pre-generate files with swig to remove the dependency but
it would be nice if this worked as expected.

Thanks!

ismail