Add support for has_feature(cxx_alignof) and has_feature(c_alignof).

r142020 added support for has_feature(cxx_alignas). This does the same for
alignof.

llvm-svn: 223186

clang/docs/LanguageExtensions.rst

@@ -543,6 +543,9 @@ C++11 alignment specifiers
 Use ``__has_feature(cxx_alignas)`` or ``__has_extension(cxx_alignas)`` to
 determine if support for alignment specifiers using ``alignas`` is enabled.
 
+Use ``__has_feature(cxx_alignof)`` or ``__has_extension(cxx_alignof)`` to
+determine if support for the ``alignof`` keyword is enabled.
+
 C++11 attributes
 ^^^^^^^^^^^^^^^^
 
@@ -857,6 +860,9 @@ C11 alignment specifiers
 Use ``__has_feature(c_alignas)`` or ``__has_extension(c_alignas)`` to determine
 if support for alignment specifiers using ``_Alignas`` is enabled.
 
+Use ``__has_feature(c_alignof)`` or ``__has_extension(c_alignof)`` to determine
+if support for the ``_Alignof`` keyword is enabled.
+
 C11 atomic operations
 ^^^^^^^^^^^^^^^^^^^^^
 

clang/lib/Lex/PPMacroExpansion.cpp

@@ -913,6 +913,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
       .Case("arc_cf_code_audited", true)
       // C11 features
       .Case("c_alignas", LangOpts.C11)
+      .Case("c_alignof", LangOpts.C11)
       .Case("c_atomic", LangOpts.C11)
       .Case("c_generic_selections", LangOpts.C11)
       .Case("c_static_assert", LangOpts.C11)
@@ -922,6 +923,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
       .Case("cxx_access_control_sfinae", LangOpts.CPlusPlus11)
       .Case("cxx_alias_templates", LangOpts.CPlusPlus11)
       .Case("cxx_alignas", LangOpts.CPlusPlus11)
+      .Case("cxx_alignof", LangOpts.CPlusPlus11)
       .Case("cxx_atomic", LangOpts.CPlusPlus11)
       .Case("cxx_attributes", LangOpts.CPlusPlus11)
       .Case("cxx_auto_type", LangOpts.CPlusPlus11)
@@ -1030,6 +1032,7 @@ static bool HasExtension(const Preprocessor &PP, const IdentifierInfo *II) {
   return llvm::StringSwitch<bool>(Extension)
            // C11 features supported by other languages as extensions.
            .Case("c_alignas", true)
+           .Case("c_alignof", true)
            .Case("c_atomic", true)
            .Case("c_generic_selections", true)
            .Case("c_static_assert", true)

clang/test/Lexer/has_extension.c

@@ -36,6 +36,14 @@ int has_c_alignas();
 int no_c_alignas();
 #endif
 
+// CHECK-PED-NONE: has_c_alignof
+// CHECK-PED-ERR: no_c_alignof
+#if __has_extension(c_alignof)
+int has_c_alignof();
+#else
+int no_c_alignof();
+#endif
+
 // Arbitrary feature to test that the extension name can be surrounded with
 // double underscores.
 // CHECK-PED-NONE: has_double_underscores

clang/test/Lexer/has_feature_c1x.c

@@ -12,7 +12,6 @@ int has_atomic();
 #else
 int no_atomic();
 #endif
-
 // CHECK-1X: has_atomic
 // CHECK-NO-1X: no_atomic
 
@@ -21,7 +20,6 @@ int has_static_assert();
 #else
 int no_static_assert();
 #endif
-
 // CHECK-1X: has_static_assert
 // CHECK-NO-1X: no_static_assert
 
@@ -30,7 +28,6 @@ int has_generic_selections();
 #else
 int no_generic_selections();
 #endif
-
 // CHECK-1X: has_generic_selections
 // CHECK-NO-1X: no_generic_selections
 
@@ -39,10 +36,17 @@ int has_alignas();
 #else
 int no_alignas();
 #endif
-
 // CHECK-1X: has_alignas
 // CHECK-NO-1X: no_alignas
 
+#if __has_feature(c_alignof)
+int has_alignof();
+#else
+int no_alignof();
+#endif
+// CHECK-1X: has_alignof
+// CHECK-NO-1X: no_alignof
+
 #if __has_feature(c_thread_local)
 int has_thread_local();
 #else

clang/test/Lexer/has_feature_cxx0x.cpp

@@ -234,6 +234,16 @@ int no_alignas();
 // CHECK-11: has_alignas
 // CHECK-NO-11: no_alignas
 
+#if __has_feature(cxx_alignof)
+int has_alignof();
+#else
+int no_alignof();
+#endif
+
+// CHECK-1Y: has_alignof
+// CHECK-11: has_alignof
+// CHECK-NO-11: no_alignof
+
 #if __has_feature(cxx_raw_string_literals)
 int has_raw_string_literals();
 #else