From 301bc621b5f774ca2998f9804730ee5d15846c8a Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron@aaronballman.com>
Date: Wed, 17 Aug 2016 13:10:42 +0000
Subject: [PATCH] Add an AST matcher for external formal linkage.

Patch by Visoiu Mistrih

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278926 91177308-0d34-0410-b5e6-96231b3b80d8
---
 docs/LibASTMatchersReference.html             | 20 ++++++++++++++++
 include/clang/ASTMatchers/ASTMatchers.h       | 24 +++++++++++++++++++
 lib/ASTMatchers/Dynamic/Registry.cpp          |  1 +
 .../ASTMatchers/ASTMatchersNarrowingTest.cpp  | 16 +++++++++++++
 4 files changed, 61 insertions(+)

diff --git a/docs/LibASTMatchersReference.html b/docs/LibASTMatchersReference.html
index b87cae230b..f97183895c 100644
--- a/docs/LibASTMatchersReference.html
+++ b/docs/LibASTMatchersReference.html
@@ -2740,6 +2740,26 @@ memberExpr(isArrow())
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1NamedDecl.html">NamedDecl</a>&gt;</td><td class="name" onclick="toggle('hasExternalFormalLinkage0')"><a name="hasExternalFormalLinkage0Anchor">hasExternalFormalLinkage</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="hasExternalFormalLinkage0"><pre>Matches a declaration that has external formal linkage.
+
+Example matches only z (matcher = varDecl(hasExternalFormalLinkage()))
+void f() {
+  int x;
+  static int y;
+}
+int z;
+
+Example matches f() because it has external formal linkage despite being
+unique to the translation unit as though it has internal likage
+(matcher = functionDecl(hasExternalFormalLinkage()))
+
+namespace {
+void f() {}
+}
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1NamedDecl.html">NamedDecl</a>&gt;</td><td class="name" onclick="toggle('hasName0')"><a name="hasName0Anchor">hasName</a></td><td>std::string  Name</td></tr>
 <tr><td colspan="4" class="doc" id="hasName0"><pre>Matches NamedDecl nodes that have the specified name.
 
diff --git a/include/clang/ASTMatchers/ASTMatchers.h b/include/clang/ASTMatchers/ASTMatchers.h
index 6f194e2a57..63ec2a4a94 100644
--- a/include/clang/ASTMatchers/ASTMatchers.h
+++ b/include/clang/ASTMatchers/ASTMatchers.h
@@ -5476,6 +5476,30 @@ AST_MATCHER_P(Stmt, forFunction, internal::Matcher<FunctionDecl>,
   return false;
 }
 
+/// \brief Matches a declaration that has external formal linkage.
+///
+/// Example matches only z (matcher = varDecl(hasExternalFormalLinkage()))
+/// \code
+/// void f() {
+///   int x;
+///   static int y;
+/// }
+/// int z;
+/// \endcode
+///
+/// Example matches f() because it has external formal linkage despite being
+/// unique to the translation unit as though it has internal likage
+/// (matcher = functionDecl(hasExternalFormalLinkage()))
+///
+/// \code
+/// namespace {
+/// void f() {}
+/// }
+/// \endcode
+AST_MATCHER(NamedDecl, hasExternalFormalLinkage) {
+  return Node.hasExternalFormalLinkage();
+}
+
 } // end namespace ast_matchers
 } // end namespace clang
 
diff --git a/lib/ASTMatchers/Dynamic/Registry.cpp b/lib/ASTMatchers/Dynamic/Registry.cpp
index 192b4b6d2a..6e594d7a7f 100644
--- a/lib/ASTMatchers/Dynamic/Registry.cpp
+++ b/lib/ASTMatchers/Dynamic/Registry.cpp
@@ -226,6 +226,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(hasEitherOperand);
   REGISTER_MATCHER(hasElementType);
   REGISTER_MATCHER(hasElse);
+  REGISTER_MATCHER(hasExternalFormalLinkage);
   REGISTER_MATCHER(hasFalseExpression);
   REGISTER_MATCHER(hasGlobalStorage);
   REGISTER_MATCHER(hasImplicitDestinationType);
diff --git a/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp b/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
index 108fd435ce..1527eacb6a 100644
--- a/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ b/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -1937,5 +1937,21 @@ TEST(NullPointerConstants, Basic) {
   EXPECT_TRUE(notMatches("int i = 0;", expr(nullPointerConstant())));
 }
 
+TEST(HasExternalFormalLinkage, Basic) {
+  EXPECT_TRUE(matches("int a = 0;", namedDecl(hasExternalFormalLinkage())));
+  EXPECT_TRUE(
+      notMatches("static int a = 0;", namedDecl(hasExternalFormalLinkage())));
+  EXPECT_TRUE(notMatches("static void f(void) { int a = 0; }",
+                         namedDecl(hasExternalFormalLinkage())));
+  EXPECT_TRUE(matches("void f(void) { int a = 0; }",
+                      namedDecl(hasExternalFormalLinkage())));
+
+  // Despite having internal semantic linkage, the anonymous namespace member
+  // has external linkage because the member has a unique name in all
+  // translation units.
+  EXPECT_TRUE(matches("namespace { int a = 0; }",
+                      namedDecl(hasExternalFormalLinkage())));
+}
+
 } // namespace ast_matchers
 } // namespace clang
-- 
2.40.0