diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
@@ -27,7 +27,6 @@
 #include "sanitizer_flags.h"
 #include "sanitizer_internal_defs.h"
 #include "sanitizer_libc.h"
-#include "sanitizer_placement_new.h"
 #include "sanitizer_platform_limits_posix.h"
 #include "sanitizer_procmaps.h"
 #include "sanitizer_ptrauth.h"
@@ -630,19 +629,24 @@
   return *reinterpret_cast<MacosVersion *>(&result);
 }
 
+void ParseVersion(const char *vers, u16 *major, u16 *minor) {
+  // Format: <major>.<minor>.<patch>\0
+  CHECK_GE(internal_strlen(vers), 5);
+  const char *p = vers;
+  *major = internal_simple_strtoll(p, &p, /*base=*/10);
+  CHECK_EQ(*p, '.');
+  p += 1;
+  *minor = internal_simple_strtoll(p, &p, /*base=*/10);
+}
+
 DarwinKernelVersion GetDarwinKernelVersion() {
   char buf[100];
   size_t len = sizeof(buf);
   int res = internal_sysctlbyname("kern.osrelease", buf, &len, nullptr, 0);
   CHECK_EQ(res, 0);
 
-  // Format: <major>.<minor>.<patch>\0
-  CHECK_GE(len, 6);
-  const char *p = buf;
-  u16 major = internal_simple_strtoll(p, &p, /*base=*/10);
-  CHECK_EQ(*p, '.');
-  p += 1;
-  u16 minor = internal_simple_strtoll(p, &p, /*base=*/10);
+  u16 major, minor;
+  ParseVersion(buf, &major, &minor);
 
   return DarwinKernelVersion(major, minor);
 }
diff --git a/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt b/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
--- a/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
+++ b/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
@@ -21,6 +21,7 @@
   sanitizer_libc_test.cpp
   sanitizer_linux_test.cpp
   sanitizer_list_test.cpp
+  sanitizer_mac_test.cpp
   sanitizer_mutex_test.cpp
   sanitizer_nolibc_test.cpp
   sanitizer_posix_test.cpp
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_mac_test.cpp b/compiler-rt/lib/sanitizer_common/tests/sanitizer_mac_test.cpp
new file mode 100644
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_mac_test.cpp
@@ -0,0 +1,58 @@
+//===-- sanitizer_mac_test.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Tests for sanitizer_mac.{h,cpp}
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_MAC
+
+#include "sanitizer_common/sanitizer_mac.h"
+
+#include "gtest/gtest.h"
+
+#include <sys/sysctl.h>  // sysctlbyname
+#include <mach/kern_return.h>  // KERN_SUCCESS
+
+namespace __sanitizer {
+
+TEST(SanitizerMac, GetMacosAlignedVersion) {
+  MacosVersion vers = GetMacosAlignedVersion();
+  EXPECT_EQ(vers.major, 10);
+  EXPECT_EQ(vers.minor, GetDarwinKernelVersion().major - 4);
+}
+
+void ParseVersion(const char *vers, u16 *major, u16 *minor);
+
+TEST(SanitizerMac, ParseVersion) {
+  u16 major, minor;
+  ParseVersion("11.22.33", &major, &minor);
+  EXPECT_EQ(major, 11);
+  EXPECT_EQ(minor, 22);
+}
+
+TEST(SanitizerMac, GetDarwinKernelVersion) {
+  DarwinKernelVersion vers = GetDarwinKernelVersion();
+  std::ostringstream oss;
+  oss << vers.major << '.' << vers.minor;
+  std::string actual = oss.str();
+
+  char buf[100];
+  size_t len = sizeof(buf);
+  int res = sysctlbyname("kern.osrelease", buf, &len, nullptr, 0);
+  ASSERT_EQ(res, KERN_SUCCESS);
+  std::string expected(buf);
+
+  // Prefix match
+  ASSERT_TRUE(expected.compare(0, actual.size(), actual) == 0);
+}
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_MAC