diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@@ -483,6 +483,8 @@
 list(APPEND COMPILER_RT_COMMON_CFLAGS ${stdlib_flag})
 list(APPEND COMPILER_RT_COMMON_LINK_FLAGS ${stdlib_flag})
 
+append_list_if(COMPILER_RT_SUPPORTS_UNWINDLIB_NONE_FLAG --unwindlib=none SANITIZER_COMMON_LINK_FLAGS)
+
 macro(append_libcxx_libs var)
   if (${var}_INTREE)
     if (SANITIZER_USE_STATIC_LLVM_UNWINDER AND (TARGET unwind_static OR HAVE_LIBUNWIND))
diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -3,9 +3,22 @@
 include(CheckCXXCompilerFlag)
 include(CheckIncludeFiles)
 include(CheckLibraryExists)
+include(CheckLinkerFlag)
 include(CheckSymbolExists)
 include(TestBigEndian)
 
+# The compiler driver may be implicitly trying to link against libunwind.
+# This is normally ok (libcxx relies on an unwinder), but if libunwind is
+# built in the same cmake invocation as compiler-rt libcxx and we've got
+# SANITIZER_USE_STATIC_LLVM_UNWINDER set, we'd be linking against the just-built
+# libunwind (and the compiler implicit -lunwind wouldn't succeed as the newly
+# built libunwind isn't installed yet). For those cases, it'd be good to
+# link with --uwnindlib=none. Check if that option works.
+llvm_check_linker_flag("--unwindlib=none" COMPILER_RT_SUPPORTS_UNWINDLIB_NONE_FLAG)
+if (COMPILER_RT_SUPPORTS_UNWINDLIB_NONE_FLAG)
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none")
+endif()
+
 function(compiler_rt_check_linker_flag flag out_var)
   cmake_push_check_state()
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${flag}")