[clang-format] Improve ObjC guessing heuristic by supporting all @keywords

[benhamilton]

Summary

This diff improves the Objective-C guessing heuristic by
replacing the hard-coded list of a subset of Objective-C @keywords
with a general check which supports all @keywords.

I also added a few more Foundation keywords which were missing from
the heuristic.

Test Plan: Unit tests updated. Ran tests with:

% make -j16 FormatTests && ./tools/clang/unittests/Format/FormatTests

[djasper]

Looks good.

cfe/trunk/lib/Format/Format.cpp

static constexpr llvm::StringLiteral FoundationIdentifiers[] = {
         "CGRectZero",
         "CGSize",
         "CGSizeMake",
         "CGVector",
         "CGVectorMake",
         "NSAffineTransform",
         "NSArray",
         "NSAttributedString",
+        "NSBlockOperation",
         "NSBundle",
         "NSCache",
         "NSCalendar",
         "NSCharacterSet",
         "NSCountedSet",
         "NSData",
         "NSDataDetector",
         "NSDecimal",
         "NSDecimalNumber",
         "NSDictionary",
         "NSEdgeInsets",
         "NSHashTable",
         "NSIndexPath",
         "NSIndexSet",
         "NSInteger",
+        "NSInvocationOperation",
         "NSLocale",
         "NSMapTable",
         "NSMutableArray",
         "NSMutableAttributedString",
         "NSMutableCharacterSet",
         "NSMutableData",
         "NSMutableDictionary",
         "NSMutableIndexSet",
         "NSMutableOrderedSet",
         "NSMutableSet",
         "NSMutableString",
         "NSNumber",
         "NSNumberFormatter",
         "NSObject",
+        "NSOperation",
+        "NSOperationQueue",
+        "NSOperationQueuePriority",
         "NSOrderedSet",
         "NSPoint",
         "NSPointerArray",
+        "NSQualityOfService",
         "NSRange",
         "NSRect",
         "NSRegularExpression",
         "NSSet",
         "NSSize",
         "NSString",
         "NSTimeZone",
         "NSUInteger",
         "NSURL",
         "NSURLComponents",
         "NSURLQueryItem",
         "NSUUID",
         "NSValue",
         "UIImage",
         "UIView",
     };
 
     for (auto Line : AnnotatedLines) {
       for (const FormatToken *FormatTok = Line->First; FormatTok;
            FormatTok = FormatTok->Next) {
         if ((FormatTok->Previous && FormatTok->Previous->is(tok::at) &&
-             (FormatTok->isObjCAtKeyword(tok::objc_interface) ||
-              FormatTok->isObjCAtKeyword(tok::objc_implementation) ||
-              FormatTok->isObjCAtKeyword(tok::objc_protocol) ||
-              FormatTok->isObjCAtKeyword(tok::objc_end) ||
+             (FormatTok->Tok.getObjCKeywordID() != tok::objc_not_keyword ||
               FormatTok->isOneOf(tok::numeric_constant, tok::l_square,
                                  tok::l_brace))) ||
             (FormatTok->Tok.isAnyIdentifier() &&
              std::binary_search(std::begin(FoundationIdentifiers),
                                 std::end(FoundationIdentifiers),
                                 FormatTok->TokenText)) ||
             FormatTok->is(TT_ObjCStringLiteral) ||
             FormatTok->isOneOf(Keywords.kw_NS_ENUM, Keywords.kw_NS_OPTIONS,

cfe/trunk/unittests/Format/FormatTest.cpp

 }
 
 TEST_F(FormatTest, FileAndCode) {
   EXPECT_EQ(FormatStyle::LK_Cpp, guessLanguage("foo.cc", ""));
   EXPECT_EQ(FormatStyle::LK_ObjC, guessLanguage("foo.m", ""));
   EXPECT_EQ(FormatStyle::LK_ObjC, guessLanguage("foo.mm", ""));
   EXPECT_EQ(FormatStyle::LK_Cpp, guessLanguage("foo.h", ""));
   EXPECT_EQ(FormatStyle::LK_ObjC, guessLanguage("foo.h", "@interface Foo\n@end\n"));
+  EXPECT_EQ(
+      FormatStyle::LK_ObjC,
+      guessLanguage("foo.h", "#define TRY(x, y) @try { x; } @finally { y; }"));
+  EXPECT_EQ(FormatStyle::LK_ObjC,
+            guessLanguage("foo.h", "#define AVAIL(x) @available(x, *))"));
+  EXPECT_EQ(FormatStyle::LK_ObjC, guessLanguage("foo.h", "@class Foo;"));
   EXPECT_EQ(FormatStyle::LK_Cpp, guessLanguage("foo", ""));
   EXPECT_EQ(FormatStyle::LK_ObjC, guessLanguage("foo", "@interface Foo\n@end\n"));
   EXPECT_EQ(FormatStyle::LK_ObjC,
             guessLanguage("foo.h", "int DoStuff(CGRect rect);\n"));
   EXPECT_EQ(
       FormatStyle::LK_ObjC,
       guessLanguage("foo.h",
                     "#define MY_POINT_MAKE(x, y) CGPointMake((x), (y));\n"));