Ensure we are nearly always in fast mode on V8

See: https://stackoverflow.com/a/24989927/1518408

lib/compiler/visitor.js

@@ -18,8 +18,9 @@ class ASTVisitor {
     // Simple AST node visitor builder for PEG.js
     static build( functions ) {
 
-        const visitor = new ASTVisitor();
+        let visitor = new ASTVisitor();
         util.extend( visitor, functions );
+        visitor = util.enforceFastProperties( visitor );
         return visitor.visit.bind( visitor );
 
     }

lib/util/objects.js

@@ -109,6 +109,27 @@ const objects = {
 
     },
 
+    // Will ensure on V8 that that property access is always in fast mode
+    // See: https://stackoverflow.com/a/24989927/1518408
+    enforceFastProperties( o ) {
+
+        /* eslint no-unreachable: 0 */
+
+        function Sub() { }
+        Sub.prototype = o;
+        const receiver = new Sub();
+        function ic() {
+
+            return typeof receiver.foo;
+
+        }
+        ic();
+        ic();
+        return o;
+        eval( "o" + o );
+
+    },
+
 };
 
 module.exports = objects;

src/parser.pegjs

@@ -93,7 +93,7 @@
   function createNode( type, details ) {
     const node = new ast.Node( type, location() );
     util.extend( node, details );
-    return node;
+    return util.enforceFastProperties( node );
   }
 }