1 /*
   2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package jdk.nashorn.internal.runtime;
  26 
  27 import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup;
  28 
  29 import jdk.nashorn.internal.codegen.CompilerConstants.Call;
  30 
  31 /**
  32  * A class with static helper methods invoked from generated bytecode for setting values of parameters of variable-arity
  33  * functions.
  34  */
  35 public final class ArgumentSetter {
  36     private ArgumentSetter() {}
  37 
  38     /** Method handle for setting a function argument at a given index in an arguments object. Used from generated bytecode */
  39     public static final Call SET_ARGUMENT      = staticCallNoLookup(ArgumentSetter.class, "setArgument", void.class, Object.class, ScriptObject.class, int.class);
  40 
  41     /** Method handle for setting a function argument at a given index in an arguments array. Used from generated bytecode */
  42     public static final Call SET_ARRAY_ELEMENT = staticCallNoLookup(ArgumentSetter.class, "setArrayElement", void.class, Object.class, Object[].class, int.class);
  43 
  44 
  45     /**
  46      * Used from generated bytecode to invoke {@link ScriptObject#setArgument(int, Object)} without having to reorder
  47      * the arguments on the stack. When we're generating a store into the argument, we first have the value on the
  48      * stack, and only afterwards load the target object and the index.
  49      * @param value the value to write at the given argument index.
  50      * @param arguments the arguments object that we're writing the value to
  51      * @param key the index of the argument
  52      */
  53     public static void setArgument(final Object value, final ScriptObject arguments, final int key) {
  54         arguments.setArgument(key, value);
  55     }
  56 
  57     /**
  58      * Used from generated bytecode to set a variable arity parameter - an array element - without having to reorder
  59      * the arguments on the stack. When we're generating a store into the array, we first have the value on the
  60      * stack, and only afterwards load the target array and the index.
  61      * @param value the value to write at the given argument index.
  62      * @param arguments the arguments array that we're writing the value to
  63      * @param key the index of the argument
  64      */
  65     public static void setArrayElement(final Object value, final Object[] arguments, final int key) {
  66         arguments[key] = value;
  67     }
  68 }