Add matcher for linkage specification

Patch by Jacques Pienaar.

llvm-svn: 217135

clang/docs/LibASTMatchersReference.html

@@ -246,6 +246,16 @@ Example matches f
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('linkageSpecDecl0')"><a name="linkageSpecDecl0Anchor">linkageSpecDecl</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1LinkageSpecDecl.html">LinkageSpecDecl</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="linkageSpecDecl0"><pre>Matches a declaration of a linkage specification.
+
+Given
+  extern "C" {}
+linkageSpecDecl()
+  matches "extern "C" {}"
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('methodDecl0')"><a name="methodDecl0Anchor">methodDecl</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1CXXMethodDecl.html">CXXMethodDecl</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="methodDecl0"><pre>Matches method declarations.
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -156,6 +156,17 @@ anything() {
 /// \endcode
 const internal::VariadicAllOfMatcher<Decl> decl;
 
+/// \brief Matches a declaration of a linkage specification.
+///
+/// Given
+/// \code
+///   extern "C" {}
+/// \endcode
+/// linkageSpecDecl()
+///   matches "extern "C" {}"
+const internal::VariadicDynCastAllOfMatcher<Decl, LinkageSpecDecl>
+    linkageSpecDecl;
+
 /// \brief Matches a declaration of anything that could have a name.
 ///
 /// Example matches \c X, \c S, the anonymous union type, \c i, and \c U;

clang/unittests/ASTMatchers/ASTMatchersTest.cpp

@@ -377,6 +377,11 @@ TEST(DeclarationMatcher, hasDeclContext) {
                           hasName("M"), hasDeclContext(namespaceDecl()))))));
 }
 
+TEST(DeclarationMatcher, LinkageSpecification) {
+  EXPECT_TRUE(matches("extern \"C\" { void foo() {}; }", linkageSpecDecl()));
+  EXPECT_TRUE(notMatches("void foo() {};", linkageSpecDecl()));
+}
+
 TEST(ClassTemplate, DoesNotMatchClass) {
   DeclarationMatcher ClassX = classTemplateDecl(hasName("X"));
   EXPECT_TRUE(notMatches("class X;", ClassX));