[CMake][libcxxabi] Support merging objects when statically linking un…

…winder

When using LLVM unwinder and static unwinder option is set, merge
libunwind and libc++abi objects into a single archive. libc++ already
supports merging libc++abi.a and libc++.a into a single archive; with
this change, it is possible to also include libunwind.a in the same
archive which is useful when doing static link and using libc++ as
a default C++ library and compiler-rt as a default runtime library.

Differential Revision: https://reviews.llvm.org/D39949

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@318563 91177308-0d34-0410-b5e6-96231b3b80d8

src/CMakeLists.txt

@@ -151,7 +151,13 @@ endif()
 
 # Build the static library.
 if (LIBCXXABI_ENABLE_STATIC)
-  add_library(cxxabi_static STATIC $<TARGET_OBJECTS:cxxabi_objects>)
+  set(cxxabi_static_sources $<TARGET_OBJECTS:cxxabi_objects>)
+  if (LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_ENABLE_STATIC_UNWINDER)
+    if (TARGET unwind_static OR HAVE_LIBUNWIND)
+      list(APPEND cxxabi_static_sources $<TARGET_OBJECTS:unwind_objects>)
+    endif()
+  endif()
+  add_library(cxxabi_static STATIC ${cxxabi_static_sources})
   target_link_libraries(cxxabi_static ${LIBCXXABI_LIBRARIES})
   set_target_properties(cxxabi_static
                         PROPERTIES