[libcxx-commits] [libcxx] [libc++][module] Fixes std::string UDL. (PR #75000)

[Louis Dionne via libcxx-commits]

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@@ -182,14 +182,37 @@ void header_exportable_declarations::registerMatchers(clang::ast_matchers::Match
 /// * exception has equality operators for the type \c exception_ptr
 /// * initializer_list has the functions \c begin and \c end
 ///
-/// \warning In some cases the returned name can be an empty string.
-/// The cause has not been investigated.
+/// When the named declaration uses a reserved name the result is an
+/// empty string.
 static std::string get_qualified_name(const clang::NamedDecl& decl) {
-  std::string result = decl.getQualifiedNameAsString();
-
-  if (result.starts_with("std::__1::"))
-    result.erase(5, 5);
-
+  std::string result = decl.getNameAsString();
+  // Reject reserved names (ignoring _ in global namespace).
+  if (result.size() >= 2 && result[0] == '_')
+    if (result[1] == '_' || std::isupper(result[1]))
+      if (result != "_Exit")
+        return "";
+
+  for (auto* context = llvm::dyn_cast_or_null<clang::NamespaceDecl>(decl.getDeclContext()); //
+       context;
+       context = llvm::dyn_cast_or_null<clang::NamespaceDecl>(context->getDeclContext())) {
+    std::string ns = std::string(context->getName());
+
+    if (ns.starts_with("__")) {
+      // When the reserved name is an inline namespace the namespace is
+      // not added to the qualified name instead of removed. Libc++ uses
+      // several inline namespace with reserved names. For example,
+      // __1 for every declaration, __cpo in range-based algorithms.
+	  //
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ldionne wrote:

Tabs here I think.

https://github.com/llvm/llvm-project/pull/75000