diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -509,31 +509,24 @@
 )
 
 # Generate outline atomics helpers from lse.S base
-set(CUSTOM_FLAGS ${CMAKE_C_FLAGS})
-if(NOT ANDROID)
-  append_list_if(COMPILER_RT_HAS_VISIBILITY_HIDDEN_FLAG -DVISIBILITY_HIDDEN CUSTOM_FLAGS)
-endif()
-append_list_if(COMPILER_RT_HAS_ASM_LSE -DHAS_ASM_LSE CUSTOM_FLAGS)
-string(REPLACE " " "\t" CUSTOM_FLAGS "${CUSTOM_FLAGS}")
 set(OA_HELPERS_DIR "${CMAKE_CURRENT_BINARY_DIR}/outline_atomic_helpers.dir")
-file(MAKE_DIRECTORY ${OA_HELPERS_DIR})
+file(MAKE_DIRECTORY "${OA_HELPERS_DIR}")
 
 foreach(pat cas swp ldadd ldclr ldeor ldset)
   foreach(size 1 2 4 8 16)
     foreach(model 1 2 3 4)
       if(pat STREQUAL "cas" OR NOT size STREQUAL "16")
-        set(helper_asm ${OA_HELPERS_DIR}/outline_atomic_${pat}${size}_${model}.S)
+        set(helper_asm "${OA_HELPERS_DIR}/outline_atomic_${pat}${size}_${model}.S")
         add_custom_command(
           OUTPUT ${helper_asm}
-          COMMAND ${CMAKE_C_COMPILER} -E ${CUSTOM_FLAGS} -DL_${pat} -DSIZE=${size} -DMODEL=${model}
-                  ${CMAKE_CURRENT_SOURCE_DIR}/aarch64/lse.S -o ${helper_asm}
-          DEPENDS aarch64/lse.S assembly.h
+          COMMAND ${CMAKE_COMMAND} -E create_symlink "${CMAKE_CURRENT_SOURCE_DIR}/aarch64/lse.S" "${helper_asm}"
         )
-        set_source_files_properties(${helper_asm} PROPERTIES GENERATED TRUE)
-        set(aarch64_SOURCES
-          ${aarch64_SOURCES}
-          ${helper_asm}
+        set_source_files_properties("${helper_asm}"
+          PROPERTIES
+          COMPILE_DEFINITIONS "L_${pat};SIZE=${size};MODEL=${model}"
+          INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}"
         )
+        list(APPEND aarch64_SOURCES "${helper_asm}")
       endif()
     endforeach(model)
   endforeach(size)
@@ -687,6 +680,8 @@
     append_list_if(COMPILER_RT_HAS_VISIBILITY_HIDDEN_FLAG VISIBILITY_HIDDEN BUILTIN_DEFS)
   endif()
 
+  append_list_if(COMPILER_RT_HAS_ASM_LSE -DHAS_ASM_LSE BUILTIN_DEFS)
+
   foreach (arch ${BUILTIN_SUPPORTED_ARCH})
     if (CAN_TARGET_${arch})
       # For ARM archs, exclude any VFP builtins if VFP is not supported
diff --git a/compiler-rt/lib/builtins/aarch64/lse.S b/compiler-rt/lib/builtins/aarch64/lse.S
--- a/compiler-rt/lib/builtins/aarch64/lse.S
+++ b/compiler-rt/lib/builtins/aarch64/lse.S
@@ -2,7 +2,7 @@
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-#include "../assembly.h"
+#include "assembly.h"
 
 // Out-of-line LSE atomics helpers. Ported from libgcc library.
 // N = {1, 2, 4, 8}