1 /*
2 * Copyright (c) 2010, 2014, 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
26 package jdk.nashorn.internal.runtime;
27
28 import java.lang.invoke.MethodHandle;
29 import jdk.nashorn.internal.objects.annotations.SpecializedFunction;
30 import jdk.nashorn.internal.objects.annotations.SpecializedFunction.LinkLogic;
31
32 /**
33 * Specialization info for a {@link SpecializedFunction}
34 */
35 public final class Specialization {
36 private final MethodHandle mh;
37 private final Class<? extends LinkLogic> linkLogicClass;
38 private final boolean isOptimistic;
39 private final boolean convertsNumericArgs;
40
41 /**
42 * Constructor
43 *
44 * @param mh invoker method handler
45 */
46 public Specialization(final MethodHandle mh) {
47 this(mh, false, true);
48 }
49
50 /**
51 * Constructor
52 *
53 * @param mh invoker method handler
54 * @param isOptimistic is this an optimistic native method, i.e. can it throw {@link UnwarrantedOptimismException}
55 * which would have to lead to a relink and return value processing
56 * @param convertsNumericArgs true if it is safe to convert arguments to numbers
57 */
58 public Specialization(final MethodHandle mh, final boolean isOptimistic, final boolean convertsNumericArgs) {
59 this(mh, null, isOptimistic, convertsNumericArgs);
60 }
61
62 /**
63 * Constructor
64 *
65 * @param mh invoker method handler
66 * @param linkLogicClass extra link logic needed for this function. Instances of this class also contains logic for checking
67 * if this can be linked on its first encounter, which is needed as per our standard linker semantics
68 * @param isOptimistic is this an optimistic native method, i.e. can it throw {@link UnwarrantedOptimismException}
69 * which would have to lead to a relink and return value processing
70 * @param convertsNumericArgs true if it is safe to convert arguments to numbers
71 */
72 public Specialization(final MethodHandle mh, final Class<? extends LinkLogic> linkLogicClass,
73 final boolean isOptimistic, final boolean convertsNumericArgs) {
74 this.mh = mh;
75 this.isOptimistic = isOptimistic;
76 this.convertsNumericArgs = convertsNumericArgs;
77 if (linkLogicClass != null) {
78 //null out the "empty" link logic class for optimization purposes
79 //we only use the empty instance because we can't default class annotations
80 //to null
81 this.linkLogicClass = LinkLogic.isEmpty(linkLogicClass) ? null : linkLogicClass;
82 } else {
83 this.linkLogicClass = null;
84 }
85 }
86
87 /**
88 * Get the method handle for the invoker of this ScriptFunction
89 * @return the method handle
90 */
91 public MethodHandle getMethodHandle() {
92 return mh;
93 }
94
95 /**
96 * Get the link logic class for this ScriptFunction
97 * @return link logic class info, i.e. one whose instance contains stuff like
98 * "do we need exception check for every call", and logic to check if we may link
99 */
100 public Class<? extends LinkLogic> getLinkLogicClass() {
101 return linkLogicClass;
102 }
103
104 /**
105 * An optimistic specialization is one that can throw UnwarrantedOptimismException.
106 * This is allowed for native methods, as long as they are functional, i.e. don't change
107 * any state between entering and throwing the UOE. Then we can re-execute a wider version
108 * of the method in the continuation. Rest-of method generation for optimistic builtins is
109 * of course not possible, but this approach works and fits into the same relinking
110 * framework
111 *
112 * @return true if optimistic
113 */
114 public boolean isOptimistic() {
115 return isOptimistic;
116 }
117
118 /**
119 * Check if this function converts arguments for numeric parameters to numbers
120 * so it's safe to pass booleans as 0 and 1
121 *
122 * @return true if it is safe to convert arguments to numbers
123 */
124 public boolean convertsNumericArgs() {
125 return convertsNumericArgs;
126 }
127
128 }
129