Making 'mx javadoc --unified' part of the gate

mx.truffle/mx_truffle.py

@@ -56,6 +56,8 @@ def sldebug(args):
     mx.run_java(vmArgs + ['-cp', mx.classpath("com.oracle.truffle.sl.tools"), "com.oracle.truffle.sl.tools.debug.SLREPL"] + slArgs)
 
 def _truffle_gate_runner(args, tasks):
+    with Task('Truffle Javadoc', tasks) as t:
+        if t: mx.javadoc(['--unified'])
     with Task('Truffle UnitTests', tasks) as t:
         if t: unittest(['--suite', 'truffle', '--enable-timing', '--verbose', '--fail-fast'])
     with Task('Truffle Signature Tests', tasks) as t:

truffle/com.oracle.truffle.api.object/src/com/oracle/truffle/api/object/Layout.java

@@ -86,6 +86,7 @@ public static Layout createLayout() {
      * @param objectType that describes the object instance with this shape.
      * @param sharedData for language-specific use
      * @param id for language-specific use
+     * @return new instance of a shape
      */
     public abstract Shape createShape(ObjectType objectType, Object sharedData, int id);
 

truffle/com.oracle.truffle.api.object/src/com/oracle/truffle/api/object/Property.java

@@ -35,7 +35,10 @@ protected Property() {
     /**
      * Create a new property.
      *
+     * @param key the key of the property
+     * @param location location of the property
      * @param flags for language-specific use
+     * @return new instance of the property
      */
     public static Property create(Object key, Location location, int flags) {
         return Layout.getFactory().createProperty(key, location, flags);