Swift: Extract KeyPath applications and KeyPathDot expressions.

Author: MathiasVP

swift/codegen/schema.yml

@@ -390,6 +390,8 @@ InOutExpr:
 
 KeyPathApplicationExpr:
   _extends: Expr
+  base: Expr
+  key_path: Expr
 
 KeyPathDotExpr:
   _extends: Expr

swift/extractor/visitors/ExprVisitor.h

@@ -509,6 +509,22 @@ class ExprVisitor : public AstVisitorBase<ExprVisitor> {
     dispatcher_.emit(IfExprsTrap{label, condLabel, thenLabel, elseLabel});
   }
 
+  void visitKeyPathDotExpr(swift::KeyPathDotExpr* expr) {
+    auto label = dispatcher_.assignNewLabel(expr);
+    dispatcher_.emit(KeyPathDotExprsTrap{label});
+  }
+
+  void visitKeyPathApplicationExpr(swift::KeyPathApplicationExpr* expr) {
+    auto label = dispatcher_.assignNewLabel(expr);
+    assert(expr->getBase() && "KeyPathApplicationExpr has getBase()");
+    assert(expr->getKeyPath() && "KeyPathApplicationExpr has getKeyPath()");
+    
+    auto baseLabel = dispatcher_.fetchLabel(expr->getBase());
+    auto keyPathLabel = dispatcher_.fetchLabel(expr->getKeyPath());
+
+    dispatcher_.emit(KeyPathApplicationExprsTrap{label, baseLabel, keyPathLabel});
+  }
+
  private:
   TrapLabel<ArgumentTag> emitArgument(const swift::Argument& arg) {
     auto argLabel = dispatcher_.createLabel<ArgumentTag>();

swift/ql/lib/codeql/swift/generated/expr/KeyPathApplicationExpr.qll

@@ -3,4 +3,18 @@ import codeql.swift.elements.expr.Expr
 
 class KeyPathApplicationExprBase extends @key_path_application_expr, Expr {
   override string getAPrimaryQlClass() { result = "KeyPathApplicationExpr" }
+
+  Expr getBase() {
+    exists(Expr x |
+      key_path_application_exprs(this, x, _) and
+      result = x.resolve()
+    )
+  }
+
+  Expr getKeyPath() {
+    exists(Expr x |
+      key_path_application_exprs(this, _, x) and
+      result = x.resolve()
+    )
+  }
 }

swift/ql/lib/swift.dbscheme

@@ -888,7 +888,9 @@ in_out_exprs(
 );
 
 key_path_application_exprs(
-  unique int id: @key_path_application_expr
+  unique int id: @key_path_application_expr,
+  int base: @expr ref,
+  int key_path: @expr ref
 );
 
 key_path_dot_exprs(