diff --git a/libcxx/cmake/caches/Generic-asan.cmake b/libcxx/cmake/caches/Generic-asan.cmake
--- a/libcxx/cmake/caches/Generic-asan.cmake
+++ b/libcxx/cmake/caches/Generic-asan.cmake
@@ -1 +1,2 @@
 set(LLVM_USE_SANITIZER "Address" CACHE STRING "")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mllvm -asan-use-private-alias=1" CACHE INTERNAL "")