[CMake] Support statically linking dependencies only to shared or static library

Currently it's possible to select whether to statically link unwinder
or the C++ ABI library, but this option applies to both the shared
and static library. However, in some scenarios it may be desirable to
only statically link unwinder and C++ ABI library into static C++
library since for shared C++ library we can rely on dynamic linking
and linker scripts. This change enables selectively enabling or
disabling statically linking only to shared or static library.

Differential Revision: https://reviews.llvm.org/D49502

1 files changed, 17 insertions, 9 deletions

diff --git a/libcxxabi/src/CMakeLists.txt b/libcxxabi/src/CMakeLists.txt
index 5a929cff170..75c7e6d92ed 100644
--- a/libcxxabi/src/CMakeLists.txt
+++ b/libcxxabi/src/CMakeLists.txt
@@ -61,19 +61,27 @@ if (LIBCXXABI_USE_LLVM_UNWINDER)
   # Prefer using the in-tree version of libunwind, either shared or static. If
   # none are found fall back to using -lunwind.
   # FIXME: Is it correct to prefer the static version of libunwind?
-  if (NOT LIBCXXABI_ENABLE_STATIC_UNWINDER AND (TARGET unwind_shared OR HAVE_LIBUNWIND))
-    list(APPEND LIBCXXABI_LIBRARIES unwind_shared)
-  elseif (LIBCXXABI_ENABLE_STATIC_UNWINDER AND (TARGET unwind_static OR HAVE_LIBUNWIND))
-    list(APPEND LIBCXXABI_LIBRARIES unwind_static)
+  if (NOT LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY AND (TARGET unwind_shared OR HAVE_LIBUNWIND))
+    list(APPEND LIBCXXABI_SHARED_LIBRARIES unwind_shared)
+  elseif (LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY AND (TARGET unwind_static OR HAVE_LIBUNWIND))
+    list(APPEND LIBCXXABI_SHARED_LIBRARIES unwind_static)
   else()
-    list(APPEND LIBCXXABI_LIBRARIES unwind)
+    list(APPEND LIBCXXABI_SHARED_LIBRARIES unwind)
+  endif()
+  if (NOT LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY AND (TARGET unwind_shared OR HAVE_LIBUNWIND))
+    list(APPEND LIBCXXABI_STATIC_LIBRARIES unwind_shared)
+  elseif (LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY AND (TARGET unwind_static OR HAVE_LIBUNWIND))
+      # We handle this by directly merging libunwind objects into libc++abi.
+  else()
+    list(APPEND LIBCXXABI_STATIC_LIBRARIES unwind)
   endif()
 else()
   add_library_flags_if(LIBCXXABI_HAS_GCC_S_LIB gcc_s)
 endif()
 if (MINGW)
   # MINGW_LIBRARIES is defined in config-ix.cmake
-  list(APPEND LIBCXXABI_LIBRARIES ${MINGW_LIBRARIES})
+  list(APPEND LIBCXXABI_SHARED_LIBRARIES ${MINGW_LIBRARIES})
+  list(APPEND LIBCXXABI_STATIC_LIBRARIES ${MINGW_LIBRARIES})
 endif()
 
 # Setup flags.
@@ -130,7 +138,7 @@ if (LIBCXXABI_ENABLE_SHARED)
   if(COMMAND llvm_setup_rpath)
     llvm_setup_rpath(cxxabi_shared)
   endif()
-  target_link_libraries(cxxabi_shared ${LIBCXXABI_LIBRARIES})
+  target_link_libraries(cxxabi_shared ${LIBCXXABI_SHARED_LIBRARIES})
   set_target_properties(cxxabi_shared
                         PROPERTIES
                           CXX_EXTENSIONS
@@ -155,13 +163,13 @@ endif()
 # Build the static library.
 if (LIBCXXABI_ENABLE_STATIC)
   set(cxxabi_static_sources $<TARGET_OBJECTS:cxxabi_objects>)
-  if (LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_ENABLE_STATIC_UNWINDER)
+  if (LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY)
     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})
+  target_link_libraries(cxxabi_static ${LIBCXXABI_STATIC_LIBRARIES})
   set_target_properties(cxxabi_static
                         PROPERTIES
                           CXX_EXTENSIONS