diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -106,6 +106,7 @@
 static const uint64_t kRISCV64_ShadowOffset64 = 0xd55550000;
 static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
+static const uint64_t kFreeBSDAArch64_ShadowOffset64 = 1ULL << 47;
 static const uint64_t kFreeBSDKasan_ShadowOffset64 = 0xdffff7c000000000;
 static const uint64_t kNetBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kNetBSD_ShadowOffset64 = 1ULL << 46;
@@ -518,6 +519,8 @@
       Mapping.Offset = kPPC64_ShadowOffset64;
     else if (IsSystemZ)
       Mapping.Offset = kSystemZ_ShadowOffset64;
+    else if (IsFreeBSD && IsAArch64)
+        Mapping.Offset = kFreeBSDAArch64_ShadowOffset64;
     else if (IsFreeBSD && !IsMIPS64) {
       if (IsKasan)
         Mapping.Offset = kFreeBSDKasan_ShadowOffset64;