[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

libcxx/CMakeLists.txt

@@ -61,6 +61,7 @@ option(LIBCXX_ENABLE_MONOTONIC_CLOCK
    This option may only be used when LIBCXX_ENABLE_THREADS=OFF." ON)
 option(LIBCXX_INSTALL_HEADERS "Install the libc++ headers." ON)
 option(LIBCXX_INSTALL_SUPPORT_HEADERS "Install libc++ support headers." ON)
+option(LIBCXX_ENABLE_STATIC_ABI_LIBRARY "Statically link the ABI library" OFF)
 set(LIBCXX_SYSROOT "" CACHE STRING "Use alternate sysroot.")
 set(LIBCXX_GCC_TOOLCHAIN "" CACHE STRING "Use alternate GCC toolchain.")
 if (LIBCXX_BUILT_STANDALONE)
@@ -68,6 +69,14 @@ if (LIBCXX_BUILT_STANDALONE)
       "Define the sanitizer used to build the library and tests")
 endif()
 
+if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
+  if (APPLE)
+    message(FATAL_ERROR "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is not supported on OS X")
+  else()
+    message(WARNING "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is an experimental option")
+  endif()
+endif()
+
 set(CXXABIS none libcxxabi libcxxrt libstdc++ libsupc++)
 if (NOT LIBCXX_CXX_ABI)
   if (NOT DEFINED LIBCXX_BUILT_STANDALONE AND

libcxx/cmake/Modules/HandleLibCXXABI.cmake

@@ -78,7 +78,11 @@ if ("${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "libstdc++" OR
 elseif ("${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "libcxxabi")
   if (LIBCXX_CXX_ABI_INTREE)
     # Link against just-built "cxxabi" target.
-    set(CXXABI_LIBNAME cxxabi)
+    if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
+        set(CXXABI_LIBNAME cxxabi_static)
+    else()
+        set(CXXABI_LIBNAME cxxabi_shared)
+    endif()
     set(LIBCXX_LIBCPPABI_VERSION "2" PARENT_SCOPE)
   else()
     # Assume c++abi is installed in the system, rely on -lc++abi link flag.

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.

libcxx/test/CMakeLists.txt

@@ -44,6 +44,11 @@ if (LIT_EXECUTABLE)
   pythonize_bool(LIBCXX_BUILD_32_BITS)
   pythonize_bool(LIBCXX_ENABLE_THREADS)
   pythonize_bool(LIBCXX_ENABLE_MONOTONIC_CLOCK)
+  # The tests shouldn't link to any ABI library when it has been linked into
+  # libc++ statically.
+  if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
+    set(LIBCXX_CXX_ABI_LIBNAME "none")
+  endif()
   set(LIBCXX_TARGET_INFO "libcxx.test.target_info.LocalTI" CACHE STRING
       "TargetInfo to use when setting up test environment.")
   set(LIBCXX_EXECUTOR "None" CACHE STRING