diff --git a/llvm-build/build.py b/llvm-build/build.py
index 50e1d69c4904d02df5f625a816c69ae57669f0d4..0e97dd4c0d474b3c95447c603cbf0adc57d6e3db 100755
--- a/llvm-build/build.py
+++ b/llvm-build/build.py
@@ -767,6 +767,13 @@ class LlvmCore(BuildUtils):
                           common_defines,
                           env=env)
 
+        # First of all build compiler-rt because it's needed to be built before libunwind and etc.
+        if not self.build_config.build_only:
+            self.invoke_ninja(out_path=build_dir,
+                              env=env,
+                              target=["compiler-rt"],
+                              install=install)
+
         self.invoke_ninja(out_path=build_dir,
                           env=env,
                           target=build_target,