diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
@@ -59,6 +59,11 @@
 #if defined(__APPLE__)
 # define SANITIZER_MAC     1
 # include <TargetConditionals.h>
+#if TARGET_OS_OSX
+#define SANITIZER_OSX 1
+#else
+#define SANITIZER_OSX 0
+#endif
 # if TARGET_OS_IPHONE
 #  define SANITIZER_IOS    1
 # else
@@ -73,6 +78,7 @@
 # define SANITIZER_MAC     0
 # define SANITIZER_IOS     0
 # define SANITIZER_IOSSIM  0
+#define SANITIZER_OSX 0
 #endif
 
 #if defined(__APPLE__) && TARGET_OS_IPHONE && TARGET_OS_WATCH
@@ -259,7 +265,7 @@
 #elif SANITIZER_RISCV64
 #define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 38)
 #elif defined(__aarch64__)
-# if SANITIZER_MAC
+#if SANITIZER_MAC && !SANITIZER_OSX
 // Darwin iOS/ARM64 has a 36-bit VMA, 64GiB VM
 #  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 36)
 # else