Add a __has_attribute macro that works much like __has_feature and __has_builtin.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@116906 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LanguageExtensions.html b/docs/LanguageExtensions.html
index 27d90c5..f27a570 100644
--- a/docs/LanguageExtensions.html
+++ b/docs/LanguageExtensions.html
@@ -136,6 +136,30 @@
<p>The feature tag is described along with the language feature below.</p>
<!-- ======================================================================= -->
+<h3 id="__has_attribute">__has_attribute</h3>
+<!-- ======================================================================= -->
+
+<p>This function-like macro takes a single identifier argument that is the name
+of an attribute. It evaluates to 1 if the attribute is supported or 0 if not. It
+can be used like this:</p>
+
+<blockquote>
+<pre>
+#ifndef __has_attribute // Optional of course.
+ #define __has_attribute(x) 0 // Compatibility with non-clang compilers.
+#endif
+
+...
+#if __has_attribute(override) || \
+#define OVERRIDE __attribute__((override))
+#else
+#define OVERRIDE
+#endif
+...
+</pre>
+</blockquote>
+
+<!-- ======================================================================= -->
<h2 id="has_include">Include File Checking Macros</h2>
<!-- ======================================================================= -->