[cfe-dev] How to build shared and static libclang* files

[Tom Stellard via cfe-dev]

On 05/08/2019 12:10 PM, Wink Saville wrote:
> I've updated my POC,
> https://github.com/winksaville/llvm-project/tree/Support-building-shared-and-static-libraries-simultaneously,
> so it now provides cmake options for building static and shared
> libclang* libraries. By default its doing both. This is modeled after
> how libunwind works.
> 

Can you submit your patch via phabricator?

-Tom

> On Tue, May 7, 2019 at 5:56 PM Wink Saville <wink at saville.com> wrote:
>>
>> So I've got a proof of concept for building both SHARED and STATIC libraries.
>> The simple implementation that creates libclangARCMigrate.a and
>> libclangARCMigrate.so
>> is on my llvm-project fork:
>> https://github.com/winksaville/llvm-project/commit/fb314421c1dd404648e7046c6ef074e93d28e4c1
>>
>> As it turns out llvm_add_library already supported building both, but
>> I had to have it build the shared library first rather than the static library.
>> Without this change clang can be built but it fails when run:
>>
>>   $ ./bin/clang-9 --version
>>   : CommandLine Error: Option 'use-dbg-addr' registered more than once!
>>   LLVM ERROR: inconsistency in registered CommandLine options
>>
>> The reason it fails is because it was linked with libclangARCMigrate.so.9svn
>> rahter than the correct library, libclangARCMigrate.a.
>>
>>
>> As you can see in the link above the code changes were fairly small:
>>
>>   clang/cmake/modules/AddClang.cmake add_clang_library:
>>
>>    - Add support for STATIC, SHARED or both
>>    - Add support for OUTPUT_NAME
>>
>>   llvm/cmake/modules/AddLLVM.cmake llvm_add_library:
>>
>>    - Changed so when both SHARED and STATIC are passed SHARED is built
>>      first. Without this change llvm_add_library causes the shared libraries
>>      to be linked to clang rather than the static library. This compiles
>>      successfully but clang fails when run with:
>>
>>   clang/lib/ARCMigrate/CMakeLists.txt:
>>
>>    - Added STATIC SHARED so both libclangARCMigrate.a and
>>      libclangARCMigrate.so are built
>>
>>
>> The result of building with the change is both static and shared libraries
>> of libclangARCMigrate are created:
>>
>>   $ ls -al lib/*ARCM*
>>   -rw-r--r-- 1 wink users  8541496 May  7 17:37 lib/libclangARCMigrate.a
>>   lrwxrwxrwx 1 wink users       26 May  7 17:37
>> lib/libclangARCMigrate.so -> libclangARCMigrate.so.9svn
>>   -rwxr-xr-x 1 wink users 37597048 May  7 17:37 lib/libclangARCMigrate.so.9svn
>>
>> And clang runs:
>>
>>   $ ./bin/clang --version
>>   clang version 9.0.0 (git at github.com:winksaville/llvm-project
>> fb314421c1dd404648e7046c6ef074e93d28e4c1)
>>   Target: x86_64-unknown-linux-gnu
>>   Thread model: posix
>>   InstalledDir:
>> /home/wink/prgs/llvm/llvm-project/build-Support-building-shared-and-static-libraries-simultaneously/./bin
>>
>>
>> Feed back welcome!
>>
>> -- Wink