Swift: add label iteration

swift/codegen/templates/cpp_classes_h.mustache

@@ -17,6 +17,8 @@ namespace codeql {
 {{#classes}}
 
 struct {{name}}{{#has_bases}} : {{#bases}}{{^first}}, {{/first}}{{ref.name}}{{/bases}}{{/has_bases}} {
+  static constexpr const char* NAME = "{{name}}";
+
   {{#final}}
   explicit {{name}}(TrapLabel<{{name}}Tag> id) : id{id} {}
 
@@ -33,6 +35,41 @@ struct {{name}}{{#has_bases}} : {{#bases}}{{^first}}, {{/first}}{{ref.name}}{{/b
   }
   {{/final}}
 
+ {{^final}}
+ protected:
+ {{/final}}
+  template <typename F>
+  void forEachLabel(F f) {
+    {{#final}}
+    f("id", -1, id);
+    {{/final}}
+    {{#bases}}
+    {{ref.name}}::forEachLabel(f);
+    {{/bases}}
+    {{#fields}}
+    {{#is_label}}
+    {{#is_repeated}}
+    for (auto i = 0u; i < {{field_name}}.size(); ++i) {
+      {{#is_optional}}
+      if ({{field_name}}[i]) f("{{field_name}}", i, *{{field_name}}[i]);
+      {{/is_optional}}
+      {{^is_optional}}
+      f("{{field_name}}", i, {{field_name}}[i]);
+      {{/is_optional}}
+    }
+    {{/is_repeated}}
+    {{^is_repeated}}
+    {{#is_optional}}
+    if ({{field_name}}) f("{{field_name}}", -1, *{{field_name}});
+    {{/is_optional}}
+    {{^is_optional}}
+    f("{{field_name}}", -1, {{field_name}});
+    {{/is_optional}}
+    {{/is_repeated}}
+    {{/is_label}}
+    {{/fields}}
+  }
+
  protected:
   void emit({{^final}}TrapLabel<{{name}}Tag> id, {{/final}}std::ostream& out) const;
 };

swift/codegen/templates/trap_traps_h.mustache

@@ -14,12 +14,24 @@ namespace codeql {
 
 // {{table_name}}
 struct {{name}}Trap {
-{{#fields}}
+  static constexpr const char* NAME = "{{name}}Trap";
+
+  {{#fields}}
   {{type}} {{field_name}}{};
-{{/fields}}
+  {{/fields}}
+
+  template <typename F>
+  void forEachLabel(F f) {
+    {{#fields}}
+    {{#is_label}}
+    f("{{field_name}}", -1, {{field_name}});
+    {{/is_label}}
+    {{/fields}}
+  }
 };
 
 std::ostream &operator<<(std::ostream &out, const {{name}}Trap &e);
+
 {{#id}}
 
 namespace detail {

swift/extractor/infra/SwiftDispatcher.h

@@ -60,20 +60,29 @@ class SwiftDispatcher {
   }
 
   template <typename Entry>
-  void emit(const Entry& entry) {
+  void emit(Entry&& entry) {
+    entry.forEachLabel([&entry](const char* field, int index, auto& label) {
+      if (!label.valid()) {
+        std::cerr << entry.NAME << " has undefined " << field;
+        if (index >= 0) {
+          std::cerr << '[' << index << ']';
+        }
+        std::cerr << '\n';
+      }
+    });
     trap.emit(entry);
   }
 
   template <typename Entry>
-  void emit(const std::optional<Entry>& entry) {
+  void emit(std::optional<Entry>&& entry) {
     if (entry) {
-      emit(*entry);
+      emit(std::move(*entry));
     }
   }
 
   template <typename... Cases>
-  void emit(const std::variant<Cases...>& entry) {
-    std::visit([this](const auto& e) { this->emit(e); }, entry);
+  void emit(std::variant<Cases...>&& entry) {
+    std::visit([this](auto&& e) { this->emit(std::move(e)); }, std::move(entry));
   }
 
   // This is a helper method to emit TRAP entries for AST nodes that we don't fully support yet.