diff --git a/compiler-rt/lib/asan/asan_report.h b/compiler-rt/lib/asan/asan_report.h
index f7153d4810d0..b0c167dda756 100644
--- a/compiler-rt/lib/asan/asan_report.h
+++ b/compiler-rt/lib/asan/asan_report.h
@@ -12,6 +12,9 @@
 // ASan-private header for error reporting functions.
 //===----------------------------------------------------------------------===//
 
+#ifndef ASAN_REPORT_H
+#define ASAN_REPORT_H
+
 #include "asan_allocator.h"
 #include "asan_internal.h"
 #include "asan_thread.h"
@@ -92,3 +95,4 @@ void ReportMacCfReallocUnknown(uptr addr, uptr zone_ptr,
                                BufferedStackTrace *stack);
 
 }  // namespace __asan
+#endif  // ASAN_REPORT_H