Add c_alignas and cxx_alignas features

llvm-svn: 142020

clang/docs/LanguageExtensions.html

@@ -40,6 +40,7 @@
     <ul>
    <li><a href="#cxx_access_control_sfinae">C++0x SFINAE includes access control</a></li>
     <li><a href="#cxx_alias_templates">C++0x alias templates</a></li>
+    <li><a href="#cxx_alignas">C++0x alignment specifiers</a></li>
     <li><a href="#cxx_attributes">C++0x attributes</a></li>
     <li><a href="#cxx_constexpr">C++0x generalized constant expressions</a></li>
     <li><a href="#cxx_decltype">C++0x <tt>decltype()</tt></a></li>
@@ -71,6 +72,7 @@
    </ul></li>
   <li><a href="#c1x">C1X</a>
     <ul>
+    <li><a href="#c_alignas">C1X alignment specifiers</a></li>
     <li><a href="#c_generic_selections">C1X generic selections</a></li>
     <li><a href="#c_static_assert">C1X <tt>_Static_assert()</tt></a></li>
     </ul></li>
@@ -476,6 +478,12 @@ with the <tt>-std=c++0x</tt> option when compiling C++ code.</p>
 <tt>__has_extension(cxx_alias_templates)</tt> to determine if support for
 C++0x's alias declarations and alias templates is enabled.</p>
 
+<h4 id="cxx_alignas">C++0x alignment specifiers</h4>
+
+<p>Use <tt>__has_feature(cxx_alignas)</tt> or
+<tt>__has_extension(cxx_alignas)</tt> to determine if support for alignment
+specifiers using <tt>alignas</tt> is enabled.</p>
+
 <h4 id="cxx_attributes">C++0x attributes</h4>
 
 <p>Use <tt>__has_feature(cxx_attributes)</tt> or
@@ -635,6 +643,12 @@ for variadic templates is enabled.</p>
 C1X standard. As a result, all these features are enabled
 with the <tt>-std=c1x</tt> option when compiling C code.</p>
 
+<h4 id="c_alignas">C1X alignment specifiers</h4>
+
+<p>Use <tt>__has_feature(c_alignas)</tt> or <tt>__has_extension(c_alignas)</tt>
+to determine if support for alignment specifiers using <tt>_Alignas</tt>
+is enabled.</p>
+
 <h4 id="c_generic_selections">C1X generic selections</h4>
 
 <p>Use <tt>__has_feature(c_generic_selections)</tt> or

clang/lib/Lex/PPMacroExpansion.cpp

@@ -609,11 +609,13 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
            .Case("ownership_returns", true)
            .Case("ownership_takes", true)
            // C1X features
+           .Case("c_alignas", LangOpts.C1X)
            .Case("c_generic_selections", LangOpts.C1X)
            .Case("c_static_assert", LangOpts.C1X)
            // C++0x features
            .Case("cxx_access_control_sfinae", LangOpts.CPlusPlus0x)
            .Case("cxx_alias_templates", LangOpts.CPlusPlus0x)
+           .Case("cxx_alignas", LangOpts.CPlusPlus0x)
            .Case("cxx_attributes", LangOpts.CPlusPlus0x)
            .Case("cxx_auto_type", LangOpts.CPlusPlus0x)
          //.Case("cxx_constexpr", false);
@@ -702,6 +704,7 @@ static bool HasExtension(const Preprocessor &PP, const IdentifierInfo *II) {
   // must be less restrictive than HasFeature's.
   return llvm::StringSwitch<bool>(II->getName())
            // C1X features supported by other languages as extensions.
+           .Case("c_alignas", true)
            .Case("c_generic_selections", true)
            .Case("c_static_assert", true)
            // C++0x features supported by other languages as extensions.

clang/test/Lexer/has_extension.c

@@ -28,3 +28,11 @@ int has_c_generic_selections();
 int no_c_generic_selections();
 #endif
 
+// CHECK-PED-NONE: has_c_alignas
+// CHECK-PED-ERR: no_c_alignas
+#if __has_extension(c_alignas)
+int has_c_alignas();
+#else
+int no_c_alignas();
+#endif
+

clang/test/Lexer/has_feature_c1x.c

@@ -18,3 +18,12 @@ int no_generic_selections();
 
 // CHECK-1X: has_generic_selections
 // CHECK-NO-1X: no_generic_selections
+
+#if __has_feature(c_alignas)
+int has_alignas();
+#else
+int no_alignas();
+#endif
+
+// CHECK-1X: has_alignas
+// CHECK-NO-1X: no_alignas

clang/test/Lexer/has_feature_cxx0x.cpp

@@ -173,3 +173,12 @@ int no_implicit_moves();
 
 // CHECK-0X: has_implicit_moves
 // CHECK-NO-0X: no_implicit_moves
+
+#if __has_feature(cxx_alignas)
+int has_alignas();
+#else
+int no_alignas();
+#endif
+
+// CHECK-0X: has_alignas
+// CHECK-NO-0X: no_alignas