Swift: extract IfConfigDecl

This also adds `UnresolvedDeclRefExpr` tests, as `IfConfigDecl`
consistently introduces those.

Author: redsun82

swift/codegen/schema.yml

@@ -270,6 +270,16 @@ EnumCaseDecl:
 
 IfConfigDecl:
   _extends: Decl
+  _children:
+    clauses: IfConfigClause*
+
+IfConfigClause:
+  _extends: Locatable
+  _children:
+    condition: Expr?
+    elements: AstNode*
+  is_active: predicate
+  _dir: decl
 
 ImportDecl:
   _extends: Decl
@@ -545,7 +555,6 @@ TypeExpr:
 UnresolvedDeclRefExpr:
   _extends: Expr
   name: string?
-  _pragma: qltest_skip  # we should really never extract these
 
 UnresolvedDotExpr:
   _extends: Expr

swift/extractor/infra/SwiftDispatcher.h

@@ -78,7 +78,7 @@ class SwiftDispatcher {
     waitingForNewLabel = e;
     visit(e);
     if (auto l = store.get(e)) {
-      if constexpr (!std::is_base_of_v<swift::TypeBase, E>) {
+      if constexpr (std::is_base_of_v<LocatableTag, TrapTagOf<E>>) {
         attachLocation(e, *l);
       }
       return *l;
@@ -95,6 +95,10 @@ class SwiftDispatcher {
     return fetchLabelFromUnion<AstNodeTag>(node);
   }
 
+  TrapLabel<IfConfigClauseTag> fetchLabel(const swift::IfConfigClause& clause) {
+    return fetchLabel(&clause);
+  }
+
   // Due to the lazy emission approach, we must assign a label to a corresponding AST node before
   // it actually gets emitted to handle recursive cases such as recursive calls, or recursive type
   // declarations
@@ -143,6 +147,15 @@ class SwiftDispatcher {
     attachLocation(locatable->getStartLoc(), locatable->getEndLoc(), locatableLabel);
   }
 
+  void attachLocation(const swift::IfConfigClause* clause, TrapLabel<LocatableTag> locatableLabel) {
+    attachLocation(clause->Loc, clause->Loc, locatableLabel);
+  }
+
+  // Emits a Location TRAP entry and attaches it to a `Locatable` trap label for a given `SourceLoc`
+  void attachLocation(swift::SourceLoc loc, TrapLabel<LocatableTag> locatableLabel) {
+    attachLocation(loc, loc, locatableLabel);
+  }
+
   // Emits a Location TRAP entry for a list of swift entities and attaches it to a `Locatable` trap
   // label
   template <typename Locatable>
@@ -217,7 +230,8 @@ class SwiftDispatcher {
                                swift::Expr,
                                swift::Pattern,
                                swift::TypeRepr,
-                               swift::TypeBase>;
+                               swift::TypeBase,
+                               swift::IfConfigClause>;
 
   void attachLocation(swift::SourceLoc start,
                       swift::SourceLoc end,
@@ -274,6 +288,7 @@ class SwiftDispatcher {
   // TODO: The following methods are supposed to redirect TRAP emission to correpsonding visitors,
   // which are to be introduced in follow-up PRs
   virtual void visit(swift::Decl* decl) = 0;
+  virtual void visit(const swift::IfConfigClause* clause) = 0;
   virtual void visit(swift::Stmt* stmt) = 0;
   virtual void visit(swift::StmtCondition* cond) = 0;
   virtual void visit(swift::CaseLabelItem* item) = 0;

swift/extractor/infra/SwiftTagTraits.h

@@ -47,6 +47,7 @@ MAP_TAG(Expr);
 #include <swift/AST/ExprNodes.def>
 
 MAP_TAG(Decl);
+MAP_TAG(IfConfigClause);
 #define ABSTRACT_DECL(CLASS, PARENT) MAP_SUBTAG(CLASS##Decl, PARENT)
 #define DECL(CLASS, PARENT) ABSTRACT_DECL(CLASS, PARENT)
 #include <swift/AST/DeclNodes.def>

swift/extractor/visitors/DeclVisitor.cpp

@@ -358,4 +358,18 @@ void DeclVisitor::fillAbstractStorageDecl(const swift::AbstractStorageDecl& decl
   fillValueDecl(decl, entry);
 }
 
+codeql::IfConfigDecl DeclVisitor::translateIfConfigDecl(const swift::IfConfigDecl& decl) {
+  auto entry = dispatcher_.createEntry(decl);
+  entry.clauses = dispatcher_.fetchRepeatedLabels(decl.getClauses());
+  return entry;
+}
+
+codeql::IfConfigClause DeclVisitor::translateIfConfigClause(const swift::IfConfigClause& clause) {
+  auto entry = dispatcher_.createEntry(clause);
+  entry.condition = dispatcher_.fetchOptionalLabel(clause.Cond);
+  entry.elements = dispatcher_.fetchRepeatedLabels(clause.Elements);
+  entry.is_active = clause.isActive;
+  return entry;
+}
+
 }  // namespace codeql

swift/extractor/visitors/DeclVisitor.h

@@ -14,6 +14,11 @@ namespace codeql {
 class DeclVisitor : public AstVisitorBase<DeclVisitor> {
  public:
   using AstVisitorBase<DeclVisitor>::AstVisitorBase;
+  using AstVisitorBase<DeclVisitor>::visit;
+
+  void visit(const swift::IfConfigClause* clause) {
+    dispatcher_.emit(translateIfConfigClause(*clause));
+  }
 
   std::variant<codeql::ConcreteFuncDecl, codeql::ConcreteFuncDeclsTrap> translateFuncDecl(
       const swift::FuncDecl& decl);
@@ -52,6 +57,8 @@ class DeclVisitor : public AstVisitorBase<DeclVisitor> {
   codeql::ExtensionDecl translateExtensionDecl(const swift::ExtensionDecl& decl);
   codeql::ImportDecl translateImportDecl(const swift::ImportDecl& decl);
   std::optional<codeql::ModuleDecl> translateModuleDecl(const swift::ModuleDecl& decl);
+  codeql::IfConfigDecl translateIfConfigDecl(const swift::IfConfigDecl& decl);
+  codeql::IfConfigClause translateIfConfigClause(const swift::IfConfigClause& clause);
 
  private:
   std::string mangledName(const swift::ValueDecl& decl);

swift/extractor/visitors/SwiftVisitor.h

@@ -21,6 +21,7 @@ class SwiftVisitor : private SwiftDispatcher {
 
  private:
   void visit(swift::Decl* decl) override { declVisitor.visit(decl); }
+  void visit(const swift::IfConfigClause* clause) override { declVisitor.visit(clause); }
   void visit(swift::Stmt* stmt) override { stmtVisitor.visit(stmt); }
   void visit(swift::StmtCondition* cond) override { stmtVisitor.visitStmtCondition(cond); }
   void visit(swift::CaseLabelItem* item) override { stmtVisitor.visitCaseLabelItem(item); }

swift/ql/lib/codeql/swift/elements.qll

@@ -24,6 +24,7 @@ import codeql.swift.elements.decl.FuncDecl
 import codeql.swift.elements.decl.GenericContext
 import codeql.swift.elements.decl.GenericTypeDecl
 import codeql.swift.elements.decl.GenericTypeParamDecl
+import codeql.swift.elements.decl.IfConfigClause
 import codeql.swift.elements.decl.IfConfigDecl
 import codeql.swift.elements.decl.ImportDecl
 import codeql.swift.elements.decl.InfixOperatorDecl

swift/ql/lib/codeql/swift/elements/decl/IfConfigClause.qll

@@ -0,0 +1,4 @@
+// generated by codegen/codegen.py, remove this comment if you wish to edit this file
+private import codeql.swift.generated.decl.IfConfigClause
+
+class IfConfigClause extends IfConfigClauseBase { }

swift/ql/lib/codeql/swift/elements/expr/UnresolvedDeclRefExpr.qll

@@ -1,4 +1,9 @@
-// generated by codegen/codegen.py, remove this comment if you wish to edit this file
 private import codeql.swift.generated.expr.UnresolvedDeclRefExpr
 
-class UnresolvedDeclRefExpr extends UnresolvedDeclRefExprBase { }
+class UnresolvedDeclRefExpr extends UnresolvedDeclRefExprBase {
+  override string toString() {
+    result = getName() + " (unresolved)"
+    or
+    not hasName() and result = "(unresolved)"
+  }
+}

swift/ql/lib/codeql/swift/generated/GetImmediateParent.qll

@@ -28,6 +28,12 @@ Element getAnImmediateChild(Element e) {
       or
       enum_element_decl_params(e, _, x)
       or
+      if_config_clause_conditions(e, x)
+      or
+      if_config_clause_elements(e, _, x)
+      or
+      if_config_decl_clauses(e, _, x)
+      or
       pattern_binding_decl_inits(e, _, x)
       or
       pattern_binding_decl_patterns(e, _, x)