Add a __has_feature check for the 'availability' attribute

llvm-svn: 128337

clang/lib/Lex/PPMacroExpansion.cpp

@@ -530,6 +530,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
 
   return llvm::StringSwitch<bool>(II->getName())
            .Case("attribute_analyzer_noreturn", true)
+           .Case("attribute_availability", true)
            .Case("attribute_cf_returns_not_retained", true)
            .Case("attribute_cf_returns_retained", true)
            .Case("attribute_deprecated_with_message", true)

clang/test/Parser/attr-availability.c

@@ -1,4 +1,9 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
+
+#if !__has_feature(attribute_availability)
+#  error 'availability' attribute is not available
+#endif
+
 void f0() __attribute__((availability(macosx,introduced=10.2,deprecated=10.4,obsoleted=10.6)));
 
 void f1() __attribute__((availability(macosx,deprecated=10.4,introduced=10.2,obsoleted=10.6)));