[Format/ObjC] Add NS_SWIFT_NAME() and CF_SWIFT_NAME() to WhitespaceSensitiveMacros

[benhamilton]

Summary

The argument passed to the preprocessor macros NS_SWIFT_NAME(x) and
CF_SWIFT_NAME(x) is stringified before passing to
__attribute__((swift_name("x"))).

ClangFormat didn't know about this stringification, so its custom parser
tried to parse the argument(s) passed to the macro as if they were
normal function arguments.

That means ClangFormat currently incorrectly inserts whitespace
between NS_SWIFT_NAME arguments with colons and dots, so:

extern UIWindow *MainWindow(void) NS_SWIFT_NAME(getter:MyHelper.mainWindow());

becomes:

extern UIWindow *MainWindow(void) NS_SWIFT_NAME(getter : MyHelper.mainWindow());

which clang treats as a parser error:

error: 'swift_name' attribute has invalid identifier for context name [-Werror,-Wswift-name-attribute]

Thankfully, D82620 recently added the ability to treat specific macros
as "whitespace sensitive", meaning their arguments are implicitly
treated as strings (so whitespace is not added anywhere inside).

This diff adds NS_SWIFT_NAME and CF_SWIFT_NAME to
WhitespaceSensitiveMacros so their arguments are implicitly treated
as whitespace-sensitive.

Test Plan:

New tests added. Ran tests with:
% ninja FormatTests && ./tools/clang/unittests/Format/FormatTests

[MyDeveloperDay]

After this change, this

FOUNDATION_EXPORT NSString *const kFIRInstanceIDScopeFirebaseMessaging
    NS_SWIFT_NAME(InstanceIDScopeFirebaseMessaging) DEPRECATED_ATTRIBUTE;

typedef NS_ENUM(NSInteger, FIRHTTPMethod) {
  /** HTTP Method GET */
  FIRHTTPMethodGET NS_SWIFT_NAME(get),
  /** HTTP Method PUT */
  FIRHTTPMethodPUT NS_SWIFT_NAME(put),
  /** HTTP Method POST */
  FIRHTTPMethodPOST NS_SWIFT_NAME(post),
  /** HTTP Method DELETE */
  FIRHTTPMethodDELETE NS_SWIFT_NAME(delete),
  /** HTTP Method HEAD */
  FIRHTTPMethodHEAD NS_SWIFT_NAME(head),
  /** HTTP Method PATCH */
  FIRHTTPMethodPATCH NS_SWIFT_NAME(patch),
  /** HTTP Method OPTIONS */
  FIRHTTPMethodOPTIONS NS_SWIFT_NAME(options),
  /** HTTP Method TRACE */
  FIRHTTPMethodTRACE NS_SWIFT_NAME(trace),
  /** HTTP Method CONNECT */
  FIRHTTPMethodCONNECT NS_SWIFT_NAME(connect)
} NS_SWIFT_NAME(HTTPMethod);

is formatted as

FOUNDATION_EXPORT NSString *const
    kFIRInstanceIDScopeFirebaseMessaging NS_SWIFT_NAME(InstanceIDScopeFirebaseMe
ssaging) DEPRECATED_ATTRIBUTE;

typedef NS_ENUM(NSInteger, FIRHTTPMethod) {
  /** HTTP Method GET */
  FIRHTTPMethodGET NS_SWIFT_NAME(get),
      /** HTTP Method PUT */
      FIRHTTPMethodPUT NS_SWIFT_NAME(put),
          /** HTTP Method POST */
          FIRHTTPMethodPOST NS_SWIFT_NAME(post),
              /** HTTP Method DELETE */
              FIRHTTPMethodDELETE NS_SWIFT_NAME(delete),
                  /** HTTP Method HEAD */
                  FIRHTTPMethodHEAD NS_SWIFT_NAME(head),
                      /** HTTP Method PATCH */
                      FIRHTTPMethodPATCH NS_SWIFT_NAME(patch),
                          /** HTTP Method OPTIONS */
                          FIRHTTPMethodOPTIONS NS_SWIFT_NAME(options),
                              /** HTTP Method TRACE */
                              FIRHTTPMethodTRACE NS_SWIFT_NAME(trace),
                                  /** HTTP Method CONNECT */
                                  FIRHTTPMethodCONNECT NS_SWIFT_NAME(connect)
                              } NS_SWIFT_NAME(HTTPMethod);

This is logged as https://bugs.llvm.org/show_bug.cgi?id=49995

I bisected to these two sha's to see this change after I noticed this was logged, I assumed this might have been related to another potential change, but turns out to be this. (sorry!)

clang/lib/Format/Format.cpp

FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
   LLVMStyle.SortIncludes = true;
   LLVMStyle.SortJavaStaticImport = FormatStyle::SJSIO_Before;
   LLVMStyle.SortUsingDeclarations = true;
   LLVMStyle.StatementMacros.push_back("Q_UNUSED");
   LLVMStyle.StatementMacros.push_back("QT_REQUIRE_VERSION");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("STRINGIZE");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("PP_STRINGIZE");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("BOOST_PP_STRINGIZE");
+  LLVMStyle.WhitespaceSensitiveMacros.push_back("NS_SWIFT_NAME");
+  LLVMStyle.WhitespaceSensitiveMacros.push_back("CF_SWIFT_NAME");
 
   // Defaults that differ when not C++.
   if (Language == FormatStyle::LK_TableGen) {
     LLVMStyle.SpacesInContainerLiterals = false;
   }
 
   return LLVMStyle;
 }

clang/unittests/Format/FormatTestObjC.cpp

TEST_F(FormatTestObjC, ObjCSnippets) {
   verifyFormat("@import foo.bar;\n"
                "@import baz;");
 
   verifyFormat("@synthesize dropArrowPosition = dropArrowPosition_;");
 
   verifyFormat("@property(assign, nonatomic) CGFloat hoverAlpha;");
   verifyFormat("@property(assign, getter=isEditable) BOOL editable;");
 
+  verifyFormat("extern UIWindow *MainWindow(void) "
+               "NS_SWIFT_NAME(getter:MyHelper.mainWindow());");
+
+  verifyFormat("extern UIWindow *MainWindow(void) "
+               "CF_SWIFT_NAME(getter:MyHelper.mainWindow());");
+
   Style.ColumnLimit = 50;
   verifyFormat("@interface Foo\n"
                "- (void)doStuffWithFoo:(id)name\n"
                "                   bar:(id)bar\n"
                "                   baz:(id)baz\n"
                "    NS_SWIFT_NAME(doStuff(withFoo:bar:baz:));\n"
                "@end");