LIBCXXABI_LIBUNWIND_INCLUDES is already set before calling find_path, and find_path will not update it.

asl · asl · commit 1af9c7b9d4f0 · 2015-05-09T21:03:01.000Z
So cmake will throw error "include_directories given empty-string as include directory". Use other variable name for the include path and do not find the default libunwind.h in the system path. http://reviews.llvm.org/D9641 Patch by Jingyi Wei! llvm-svn: 236936
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
@@ -307,12 +307,13 @@ set(LIBCXXABI_LIBUNWIND_PATH "${LIBCXXABI_LIBUNWIND_PATH}" CACHE PATH
 include_directories(include)
 if (LIBCXXABI_USE_LLVM_UNWINDER OR LLVM_NATIVE_ARCH MATCHES ARM)
   find_path(
-    LIBCXXABI_LIBUNWIND_INCLUDES
+    LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL
     libunwind.h
     PATHS ${LIBCXXABI_LIBUNWIND_INCLUDES}
           ${LIBCXXABI_LIBUNWIND_PATH}/include
           ${CMAKE_BINARY_DIR}/${LIBCXXABI_LIBUNWIND_INCLUDES}
           ${LLVM_MAIN_SRC_DIR}/projects/libunwind/include
+    NO_DEFAULT_PATH
   )
 
   find_path(
@@ -329,7 +330,7 @@ if (LIBCXXABI_USE_LLVM_UNWINDER OR LLVM_NATIVE_ARCH MATCHES ARM)
     set(LIBCXXABI_LIBUNWIND_SOURCES "")
   endif()
 
-  include_directories("${LIBCXXABI_LIBUNWIND_INCLUDES}")
+  include_directories("${LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL}")
   include_directories("${LIBCXXABI_LIBUNWIND_SOURCES}")
 endif ()
 
