Support Objective-C/C++ source files in check_clang_tidy.py

[benhamilton]

Summary

check_clang_tidy.py currently only handles C and C++ source files.

This extends the logic to also handle Objective-C (.m) and
Objective-C++ (.mm) files.

However, by default, clang compiles .m/.mm files using Objective-C 1.0
syntax. Objective-C 2.0 has been the default in Xcode for about 10
years, and Objective-C Automatic Reference Counting (ARC) for about 6
years, so this enables both by default.

(Clients which actually want to test clang-tidy checks for Objective-C
1.0 or non-ARC files can pass custom flags to check_clang_tidy.py
after --, which will disable the Objective-C 2.0 and ARC flags).

I did not add logic to handle running clang-tidy on Objective-C header
files alone; they also use the .h file extension, so we'd need to
look inside their contents.

I included a new test to confirm the new behavior.

Depends On D38963

[hokein]

test/clang-tidy/objc-arc-and-properties.m

2

I'd suggest adding one more test for default clang behavior (Objective-C 1.0 and non-ARC).

[benhamilton]

• Add new test to confirm disabling ARC and ObjC 2.0 works

[benhamilton]

test/clang-tidy/objc-arc-and-properties.m

2

I added a new test, but I realized we shouldn't rely on default clang parameters, since they can change based on the Objective-C runtime for the platform (which is different between Linux and Mac).

[hokein]

LGTM.

test/clang-tidy/objc-arc-and-properties.m

2

Sounds good. Thanks for the explanation.

[hokein]

@benhamilton, can you rebase this patch? It failed to apply this patch after I committed D38963.

[benhamilton]

Rebase

[hokein]

Committed in rL316090.

test/clang-tidy/check_clang_tidy.py

check_clang_tidy.py [-resource-dir <resource-dir>] \
     <source-file> <check-name> <temp-file> \
     -- [optional clang-tidy arguments]
 
 Example:
   // RUN: %check_clang_tidy %s llvm-include-order %t -- -- -isystem %S/Inputs
 """
 
 import argparse
+import os
 import re
 import subprocess
 import sys
 
 
 def write_file(file_name, text):
   with open(file_name, 'w') as f:
     f.write(text)
def main():
 
   resource_dir = args.resource_dir
   assume_file_name = args.assume_filename
   input_file_name = args.input_file_name
   check_name = args.check_name
   temp_file_name = args.temp_file_name
 
   file_name_with_extension = assume_file_name or input_file_name
-
+  _, extension = os.path.splitext(file_name_with_extension)
+  if extension not in ['.c', '.hpp', '.m', '.mm']:
     extension = '.cpp'
-  if (file_name_with_extension.endswith('.c')):
-    extension = '.c'
-  if (file_name_with_extension.endswith('.hpp')):
-    extension = '.hpp'
   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.
   clang_tidy_extra_args.append('-nostdinc++')
 
   if resource_dir is not None:
     clang_tidy_extra_args.append('-resource-dir=%s' % resource_dir)
 

test/clang-tidy/objc-arc-and-properties.m

+// 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];
+}

test/clang-tidy/objc-no-arc-or-properties.m

+// 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];
+}