diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4c1e3ab..4a7d945 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -149,9 +149,22 @@
 
 # Setup the default options if LIBCXX_CXX_ABI is not specified.
 if (LIBCXX_CXX_ABI STREQUAL "default")
+  find_path(
+    LIBCXX_LIBCXXABI_INCLUDES_INTERNAL cxxabi.h
+    PATHS ${LLVM_MAIN_SRC_DIR}/projects/libcxxabi/include
+          ${LLVM_MAIN_SRC_DIR}/runtimes/libcxxabi/include
+          ${LLVM_MAIN_SRC_DIR}/../libcxxabi/include
+    NO_DEFAULT_PATH
+    NO_CMAKE_FIND_ROOT_PATH
+  )
   if (LIBCXX_TARGETING_MSVC)
     # FIXME: Figure out how to configure the ABI library on Windows.
     set(LIBCXX_CXX_ABI_LIBNAME "vcruntime")
+  elseif ((NOT LIBCXX_STANDALONE_BUILD OR HAVE_LIBCXXABI) AND
+          IS_DIRECTORY "${LIBCXX_LIBCXXABI_INCLUDES_INTERNAL}")
+    set(LIBCXX_CXX_ABI_LIBNAME "libcxxabi")
+    set(LIBCXX_CXX_ABI_INCLUDE_PATHS "${LIBCXX_LIBCXXABI_INCLUDES_INTERNAL}")
+    set(LIBCXX_CXX_ABI_INTREE 1)
   elseif (APPLE)
     set(LIBCXX_CXX_ABI_LIBNAME "libcxxabi")
     set(LIBCXX_CXX_ABI_SYSTEM 1)
diff --git a/cmake/Modules/HandleLibCXXABI.cmake b/cmake/Modules/HandleLibCXXABI.cmake
index 57f9e32..10f100f 100644
--- a/cmake/Modules/HandleLibCXXABI.cmake
+++ b/cmake/Modules/HandleLibCXXABI.cmake
@@ -98,7 +98,7 @@
     "${_LIBSUPCXX_LIBNAME}" "${_LIBSUPCXX_LIBNAME}" "${_LIBSUPCXX_INCLUDE_FILES}" "bits"
     )
 elseif ("${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "libcxxabi")
-  if (TARGET cxxabi_shared AND TARGET cxxabi_static)
+  if (LIBCXX_CXX_ABI_INTREE)
     # Link against just-built "cxxabi" target.
     set(CXXABI_SHARED_LIBNAME cxxabi_shared)
     set(CXXABI_STATIC_LIBNAME cxxabi_static)