[libcxx] Add support for linking libc++ against a static ABI library.

Summary:
This patch add the CMake option `LIBCXX_ENABLE_STATIC_ABI_LIBRARY` which, when enabled, will link libc++ against the static version of the ABI library.


Reviewers: mclow.lists, jroelofs, danalbert

Reviewed By: danalbert

Subscribers: compnerd, cfe-commits

Differential Revision: http://reviews.llvm.org/D8017

llvm-svn: 231076

1 files changed, 16 insertions, 5 deletions

diff --git a/libcxx/lib/CMakeLists.txt b/libcxx/lib/CMakeLists.txt
index fb09c63fa4d..d50b2cc0fd7 100644
--- a/libcxx/lib/CMakeLists.txt
+++ b/libcxx/lib/CMakeLists.txt
@@ -34,22 +34,33 @@ else()
     )
 endif()
 
+#if LIBCXX_CXX_ABI_LIBRARY_PATH is defined we want to add it to the search path.
+if (DEFINED LIBCXX_CXX_ABI_LIBRARY_PATH)
+  target_link_libraries(cxx "-L${LIBCXX_CXX_ABI_LIBRARY_PATH}")
+endif()
+
 if (DEFINED LIBCXX_CXX_ABI_DEPS)
   add_dependencies(cxx LIBCXX_CXX_ABI_DEPS)
 endif()
 
+set(libraries "")
+if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
+    # TODO(ericwf): Remove these GNU specific linker flags and let CMake do the
+    # configuration. This will be more portable.
+    list(APPEND libraries "-Wl,--whole-archive" "-Wl,-Bstatic")
+    list(APPEND libraries "${LIBCXX_CXX_ABI_LIBRARY}")
+    list(APPEND libraries "-Wl,-Bdynamic" "-Wl,--no-whole-archive")
+else()
+    list(APPEND libraries "${LIBCXX_CXX_ABI_LIBRARY}")
+endif()
+
 # Generate library list.
-set(libraries ${LIBCXX_CXX_ABI_LIBRARY})
 append_if(libraries LIBCXX_HAS_PTHREAD_LIB pthread)
 append_if(libraries LIBCXX_HAS_C_LIB c)
 append_if(libraries LIBCXX_HAS_M_LIB m)
 append_if(libraries LIBCXX_HAS_RT_LIB rt)
 append_if(libraries LIBCXX_HAS_GCC_S_LIB gcc_s)
 
-#if LIBCXX_CXX_ABI_LIBRARY_PATH is defined we want to add it to the search path.
-if (DEFINED LIBCXX_CXX_ABI_LIBRARY_PATH)
-  target_link_libraries(cxx "-L${LIBCXX_CXX_ABI_LIBRARY_PATH}")
-endif()
 target_link_libraries(cxx ${libraries})
 
 # Setup flags.