Index: test/clang-tidy/check_clang_tidy.py
===================================================================
--- test/clang-tidy/check_clang_tidy.py
+++ test/clang-tidy/check_clang_tidy.py
@@ -26,6 +26,7 @@
 """
 
 import argparse
+import os
 import re
 import subprocess
 import sys
@@ -53,18 +54,19 @@
   temp_file_name = args.temp_file_name
 
   file_name_with_extension = assume_file_name or input_file_name
-
-  extension = '.cpp'
-  if (file_name_with_extension.endswith('.c')):
-    extension = '.c'
-  if (file_name_with_extension.endswith('.hpp')):
-    extension = '.hpp'
+  _, extension = os.path.splitext(file_name_with_extension)
+  if extension not in ['.c', '.hpp', '.m', '.mm']:
+    extension = '.cpp'
   temp_file_name = temp_file_name + extension
 
   clang_tidy_extra_args = extra_args
   if len(clang_tidy_extra_args) == 0:
-    clang_tidy_extra_args = ['--', '--std=c++11'] \
-        if extension == '.cpp' or extension == '.hpp' else ['--']
+    clang_tidy_extra_args = ['--']
+    if extension in ['.cpp', '.hpp', '.mm']:
+      clang_tidy_extra_args.append('--std=c++11')
+    if extension in ['.m', '.mm']:
+      clang_tidy_extra_args.extend(
+          ['-fobjc-abi-version=2', '-fobjc-arc'])
 
   # Tests should not rely on STL being available, and instead provide mock
   # implementations of relevant APIs.
Index: test/clang-tidy/objc-arc-and-properties.m
===================================================================
--- /dev/null
+++ test/clang-tidy/objc-arc-and-properties.m
@@ -0,0 +1,21 @@
+// RUN: %check_clang_tidy %s misc-suspicious-semicolon %t
+
+// This test checks if Objective-C 2.0 (@properties) and
+// Automatic Reference Counting (ARC) are enabled for .m files
+// checked via check_clang_tidy.py.
+
+#if !__has_feature(objc_arc)
+#error Objective-C ARC not enabled as expected
+#endif
+
+@interface Foo
+@property (nonatomic, assign) int shouldDoStuff;
+- (void)nop;
+@end
+
+void fail(Foo *f)
+{
+  if(f.shouldDoStuff); [f nop];
+  // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: potentially unintended semicolon [misc-suspicious-semicolon]
+  // CHECK-FIXES: if(f.shouldDoStuff) [f nop];
+}
Index: test/clang-tidy/objc-no-arc-or-properties.m
===================================================================
--- /dev/null
+++ test/clang-tidy/objc-no-arc-or-properties.m
@@ -0,0 +1,29 @@
+// RUN: %check_clang_tidy %s misc-suspicious-semicolon %t -- -- -fno-objc-arc -fobjc-abi-version=1
+
+// This test ensures check_clang_tidy.py allows disabling Objective-C ARC and
+// Objective-C 2.0 via passing arguments after -- on the command line.
+//
+// (We could include a test which doesn't pass any arguments after --
+// to check if ARC and ObjC 2.0 are disabled by default, but that test
+// could change behavior based on the default Objective-C runtime for
+// the platform, which would make this test flaky.)
+
+#if __has_feature(objc_arc)
+#error Objective-C ARC unexpectedly enabled even with -fno-objc-arc 
+#endif
+
+#ifdef __OBJC2__
+#error Objective-C 2.0 unexpectedly enabled even with -fobjc-abi-version=1
+#endif
+
+@interface Foo
+- (int)shouldDoStuff;
+- (void)nop;
+@end
+
+void fail(Foo *f)
+{
+  if([f shouldDoStuff]); [f nop];
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: potentially unintended semicolon [misc-suspicious-semicolon]
+  // CHECK-FIXES: if([f shouldDoStuff]) [f nop];
+}