[clang-tidy][use-internal-linkage]fix false positives for ExportDecl (#117901)

Fixed: #97190

Author: HerrCai0907

clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.cpp

@@ -118,8 +118,11 @@ void UseInternalLinkageCheck::registerMatchers(MatchFinder *Finder) {
                 isExternStorageClass(), isExternC(),
                 // 3. template
                 isExplicitTemplateSpecialization(),
-                // 4. friend
-                hasAncestor(friendDecl()))));
+                hasAncestor(decl(anyOf(
+                    // 4. friend
+                    friendDecl(),
+                    // 5. module export decl
+                    exportDecl()))))));
   Finder->addMatcher(
       functionDecl(Common, hasBody(),
                    unless(anyOf(cxxMethodDecl(),

clang-tools-extra/docs/ReleaseNotes.rst

@@ -248,7 +248,8 @@ Changes in existing checks
   <clang-tidy/checks/misc/use-internal-linkage>` check to insert ``static``
   keyword before type qualifiers such as ``const`` and ``volatile`` and fix
   false positives for function declaration without body and fix false positives
-  for global scoped overloaded ``operator new`` and ``operator delete``.
+  for C++20 export declarations and fix false positives for global scoped
+  overloaded ``operator new`` and ``operator delete``.
 
 - Improved :doc:`modernize-avoid-c-arrays
   <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest using 

clang-tools-extra/docs/clang-tidy/checks/misc/use-internal-linkage.rst

@@ -29,6 +29,11 @@ Example:
   void fn3(); // without function body in all declaration, maybe external linkage
   void fn3();
 
+  // export declarations
+  export void fn4() {}
+  export namespace t { void fn5() {} }
+  export int v2;
+
 Options
 -------
 

clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-module.cpp

@@ -0,0 +1,20 @@
+// RUN: %check_clang_tidy -std=c++20 %s misc-use-internal-linkage %t -- -- -I%S/Inputs/use-internal-linkage
+
+module;
+
+export module test;
+
+export void single_export_fn() {}
+export int single_export_var;
+
+export {
+  void group_export_fn1() {}
+  void group_export_fn2() {}
+  int group_export_var1;
+  int group_export_var2;
+}
+
+export namespace aa {
+void namespace_export_fn() {}
+int namespace_export_var;
+} // namespace aa

clang/docs/LibASTMatchersReference.html

@@ -804,6 +804,17 @@ <h2 id="decl-matchers">Node Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('exportDecl0')"><a name="exportDecl0Anchor">exportDecl</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ExportDecl.html">ExportDecl</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="exportDecl0"><pre>Matches any export declaration.
+
+Example matches following declarations.
+  export void foo();
+  export { void foo(); }
+  export namespace { void foo(); }
+  export int v;
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('fieldDecl0')"><a name="fieldDecl0Anchor">fieldDecl</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1FieldDecl.html">FieldDecl</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="fieldDecl0"><pre>Matches field declarations.
 

clang/docs/ReleaseNotes.rst

@@ -965,6 +965,8 @@ AST Matchers
 - Ensure ``hasName`` matches template specializations across inline namespaces,
   making `matchesNodeFullSlow` and `matchesNodeFullFast` consistent.
 
+- Add ``exportDecl`` matcher to match export declaration.
+
 clang-format
 ------------
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -1236,6 +1236,17 @@ AST_MATCHER_P(TemplateArgument, equalsIntegralValue,
 extern const internal::VariadicDynCastAllOfMatcher<Stmt,
        ObjCAutoreleasePoolStmt> autoreleasePoolStmt;
 
+/// Matches any export declaration.
+///
+/// Example matches following declarations.
+/// \code
+///   export void foo();
+///   export { void foo(); }
+///   export namespace { void foo(); }
+///   export int v;
+/// \endcode
+extern const internal::VariadicDynCastAllOfMatcher<Decl, ExportDecl> exportDecl;
+
 /// Matches any value declaration.
 ///
 /// Example matches A, B, C and F

clang/lib/ASTMatchers/ASTMatchersInternal.cpp

@@ -799,6 +799,7 @@ const internal::VariadicDynCastAllOfMatcher<TypeLoc, ElaboratedTypeLoc>
 
 const internal::VariadicDynCastAllOfMatcher<Stmt, UnaryExprOrTypeTraitExpr>
     unaryExprOrTypeTraitExpr;
+const internal::VariadicDynCastAllOfMatcher<Decl, ExportDecl> exportDecl;
 const internal::VariadicDynCastAllOfMatcher<Decl, ValueDecl> valueDecl;
 const internal::VariadicDynCastAllOfMatcher<Decl, CXXConstructorDecl>
     cxxConstructorDecl;

clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp

@@ -189,6 +189,21 @@ TEST(ASTMatchersTestCUDA, HasAttrCUDA) {
                                   hasAttr(clang::attr::CUDAGlobal)));
 }
 
+TEST_P(ASTMatchersTest, ExportDecl) {
+  if (!GetParam().isCXX20OrLater()) {
+    return;
+  }
+  const std::string moduleHeader = "module;export module ast_matcher_test;";
+  EXPECT_TRUE(matches(moduleHeader + "export void foo();",
+                      exportDecl(has(functionDecl()))));
+  EXPECT_TRUE(matches(moduleHeader + "export { void foo(); int v; }",
+                      exportDecl(has(functionDecl()))));
+  EXPECT_TRUE(matches(moduleHeader + "export { void foo(); int v; }",
+                      exportDecl(has(varDecl()))));
+  EXPECT_TRUE(matches(moduleHeader + "export namespace aa { void foo(); }",
+                      exportDecl(has(namespaceDecl()))));
+}
+
 TEST_P(ASTMatchersTest, ValueDecl) {
   if (!GetParam().isCXX()) {
     // FIXME: Fix this test in non-C++ language modes.