[libcxxabi] Build both static and shared versions of libc++abi by default.

[EricWF]

Summary

This patch builds both static and shared versions of libc++abi by default. It adds/repurposes the following cmake options:

• LIBCXXABI_ENABLE_SHARED: Enable/disable building the shared library. (Previously using OFF would build the static library instead)
• LIBCXXABI_ENABLE_STATIC: Enable/disable building the static library.

This patch also re-purposes the CMake target cxxabi to be a meta-target for cxxabi_shared and cxxabi_static. This could potentially break other builds that depend on cxxabi being a library target. We will need to apply a patch to libc++'s CMake before committing this change.

Running the tests is still only supported when the shared version is built. Support for running the tests against the static library will come in another patch.

[danalbert]

LGTM.

[mclow.lists]

I'm OK with this.

[EricWF]

Add comments and clean up.

[compnerd]

src/CMakeLists.txt

75

You've added the option to build static. Great, let me enable that, on Darwin. You just built it dynamically here. I think that you should either add an FATAL_ERROR message if static is used on Darwin (which I think is harsh) or support both builds on Darwin as well.

83

This is a weird name. It is rather misleading as well. I get why you are doing the object library (no need to rebuild the objects). Perhaps cxxabi_OBJECTS ? Given that you are changing the name of the target from cxxabi to cxxabi_{shared,static}, cxxabi would be even better. Specially when you use the generator expression below ($<TARGET_OBJECTS:cxxabi>).

90

Better written as:

set(LIBCXXABI_TARGETS)

[EricWF]

Address inline comments.

src/CMakeLists.txt

83

I'll change to cxxabi_OBJECTS. I want to save cxxabi as a target name that builds both cxxabi_shared and cxxabi_static.

90

Cool, didn't know you could do that. Thanks.

[EricWF]

Address inline comments.

[EricWF]

Make changes suggested by @compnerd

[EricWF]

Fixed cxxabi_sources to be cxxabi_objects.

CMakeLists.txt

 # case of an in tree build, libc++ will prefer a dynamic libc++abi from the
 # system over a static libc++abi from the output directory.
 option(LIBCXXABI_ENABLE_SHARED "Build libc++abi as a shared library." ON)
+option(LIBCXXABI_ENABLE_STATIC "Build libc++abi as a static library." ON)
+
+if (NOT LIBCXXABI_ENABLE_SHARED AND NOT LIBCXXABI_ENABLE_STATIC)
+  message(FATAL_ERROR "libc++abi must be built as either a shared or static library.")
+endif()
 
 find_path(
   LIBCXXABI_LIBCXX_INCLUDES

src/CMakeLists.txt

   endif()
 endif()
 
-if (LIBCXXABI_ENABLE_SHARED)
-  add_library(cxxabi SHARED
-    ${LIBCXXABI_SOURCES}
-    ${LIBCXXABI_HEADERS}
-    )
-else()
-  add_library(cxxabi STATIC
-    ${LIBCXXABI_SOURCES}
-    ${LIBCXXABI_HEADERS}
-    )
-endif()
-
 include_directories("${LIBCXXABI_LIBCXX_INCLUDES}")
 
 if (LIBCXXABI_HAS_CXA_THREAD_ATEXIT_IMPL)

   append_if(libraries LIBCXXABI_HAS_GCC_EH_LIB gcc_eh)
 endif()
 
-target_link_libraries(cxxabi ${libraries})
-
 # Setup flags.
 append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_FPIC_FLAG -fPIC)
 append_if(LIBCXXABI_LINK_FLAGS LIBCXXABI_HAS_NODEFAULTLIBS_FLAG -nodefaultlibs)
 
+set(LIBCXXABI_SHARED_LINK_FLAGS "")
+
 if ( APPLE )
   if ( CMAKE_OSX_DEPLOYMENT_TARGET STREQUAL "10.6" )
     list(APPEND LIBCXXABI_COMPILE_FLAGS "-U__STRICT_ANSI__")
-    list(APPEND LIBCXXABI_LINK_FLAGS
+    list(APPEND LIBCXXABI_SHARED_LINK_FLAGS
       "-compatibility_version 1"
       "-current_version 1"
-      "-install_name /usr/lib/libc++abi.1.dylib"
-      "/usr/lib/libSystem.B.dylib")
-  else()
+      "-install_name /usr/lib/libc++abi.1.dylib")
     list(APPEND LIBCXXABI_LINK_FLAGS
+        "/usr/lib/libSystem.B.dylib")
+  else()
+    list(APPEND LIBCXXABI_SHARED_LINK_FLAGS
       "-compatibility_version 1"
       "-install_name /usr/lib/libc++abi.1.dylib")
   endif()

 
 string(REPLACE ";" " " LIBCXXABI_COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}")
 string(REPLACE ";" " " LIBCXXABI_LINK_FLAGS "${LIBCXXABI_LINK_FLAGS}")
+string(REPLACE ";" " " LIBCXXABI_SHARED_LINK_FLAGS "${LIBCXXABI_SHARED_LINK_FLAGS}")
+
+# Add a object library that contains the compiled source files.
+add_library(cxxabi_sources OBJECT ${LIBCXXABI_SOURCES} ${LIBCXXABI_HEADERS})
 
-set_target_properties(cxxabi
+set_target_properties(cxxabi_sources
   PROPERTIES
     COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}"
-    LINK_FLAGS    "${LIBCXXABI_LINK_FLAGS}"
-    OUTPUT_NAME   "c++abi"
-    VERSION       "1.0"
-    SOVERSION     "1"
   )
 
-install(TARGETS cxxabi
+set(LIBCXXABI_TARGETS "")
+
+# Build the shared library.
+if (LIBCXXABI_ENABLE_SHARED)
+  add_library(cxxabi_shared SHARED $<TARGET_OBJECTS:cxxabi_sources>)
+  target_link_libraries(cxxabi_shared ${libraries})
+  set_target_properties(cxxabi_shared
+    PROPERTIES
+      LINK_FLAGS    "${LIBCXXABI_LINK_FLAGS} ${LIBCXXABI_SHARED_LINK_FLAGS}"
+      OUTPUT_NAME   "c++abi"
+      VERSION       "1.0"
+      SOVERSION     "1"
+    )
+  list(APPEND LIBCXXABI_TARGETS "cxxabi_shared")
+endif()
+
+# Build the static library.
+if (LIBCXXABI_ENABLE_STATIC)
+  add_library(cxxabi_static STATIC $<TARGET_OBJECTS:cxxabi_sources>)
+  target_link_libraries(cxxabi_static ${libraries})
+  set_target_properties(cxxabi_static
+    PROPERTIES
+      LINK_FLAGS    "${LIBCXXABI_LINK_FLAGS}"
+      OUTPUT_NAME   "c++abi"
+  )
+  list(APPEND LIBCXXABI_TARGETS "cxxabi_static")
+endif()
+
+# Add a meta-target for both libraries.
+add_custom_target(cxxabi DEPENDS ${LIBCXXABI_TARGETS})
+
+install(TARGETS ${LIBCXXABI_TARGETS}
   LIBRARY DESTINATION lib${LIBCXXABI_LIBDIR_SUFFIX}
   ARCHIVE DESTINATION lib${LIBCXXABI_LIBDIR_SUFFIX}
   )

test/CMakeLists.txt

   ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
   @ONLY)
 
-set(LIBCXXABI_TEST_DEPS cxxabi)
+set(LIBCXXABI_TEST_DEPS cxxabi_shared)
 if (NOT LIBCXXABI_BUILT_STANDALONE)
   list(APPEND LIBCXXABI_TEST_DEPS cxx)
 endif()