[CMake] External compiler-rt-configure requires LLVMTestingSupport when including tests

[sgraenitz]

Summary

Apparently LLVMTestingSupport must be built before llvm-config can be asked for it. Symptom with LLVM_INCLUDE_TESTS=ON is:

$ ./path/to/llvm-build/bin/llvm-config --ldflags --libs testingsupport
-L/path/to/llvm-build/lib -Wl,-search_paths_first -Wl,-headerpad_max_install_names
llvm-config: error: component libraries and shared library

llvm-config: error: missing: /path/to/llvm-build/lib/libLLVMTestingSupport.a

With LLVMTestingSupport as dependency of compiler-rt-configure we get the expected behavior:

$ ./path/to/llvm-build/bin/llvm-config --ldflags --libs testingsupport
-L/path/to/llvm-build/lib -Wl,-search_paths_first -Wl,-headerpad_max_install_names
-lLLVMTestingSupport -lLLVMSupport -lLLVMDemangle

[sgraenitz]

Polishing

[sgraenitz]

FYI: Seems to be happening since D55891

[dberris]

LGTM

Thanks!

[beanz]

@phosek, does LLVM’s runtime directory do this correctly?

At some point we should try and deprecate and remove this option in favor of the LLVM directory because the LLVM approach is much more complete and robust.

[sgraenitz]

In D57521#1379837, @beanz wrote:

@phosek, does LLVM’s runtime directory do this correctly?

At some point we should try and deprecate and remove this option in favor of the LLVM directory because the LLVM approach is much more complete and robust.

My 2¢: ideally compiler-rt used imported targets. Please see my note added in D55891.

[mgorny]

Ideally we wouldn't introduce such a complex dependency for 2 test cases.

runtime/CMakeLists.txt

if(variableName MATCHES "^COMPILER_RT")
         -D${variableName}=${value})
     endif()
   endforeach()
 
   if(TARGET cxx-headers)
     set(COMPILER_RT_LIBCXX_DEPENDENCY "cxx-headers")
   endif()
 
+  if(LLVM_INCLUDE_TESTS)
+    list(APPEND COMPILER_RT_LIBCXX_DEPENDENCY LLVMTestingSupport)
+  endif()
+
   ExternalProject_Add(compiler-rt
     DEPENDS llvm-config clang ${COMPILER_RT_LIBCXX_DEPENDENCY}
     PREFIX ${COMPILER_RT_PREFIX}
     SOURCE_DIR ${COMPILER_RT_SRC_ROOT}
     STAMP_DIR ${STAMP_DIR}
     BINARY_DIR ${BINARY_DIR}
     CMAKE_ARGS ${CLANG_COMPILER_RT_CMAKE_ARGS}
                -DCMAKE_C_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang