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
26 package jdk.nashorn.internal.runtime;
27
28 import java.lang.invoke.MethodHandle;
29 import java.lang.invoke.MethodType;
30 import java.util.Collection;
31 import java.util.List;
32
33 /**
34 * This is a subclass that represents a script function that may not be regenerated.
35 * This is used for example for bound functions and builtins.
36 */
37 final class FinalScriptFunctionData extends ScriptFunctionData {
38
39 // documentation key for this function, may be null
40 private String docKey;
41
42 private static final long serialVersionUID = -930632846167768864L;
43
44 /**
45 * Constructor - used for bind
46 *
47 * @param name name
48 * @param arity arity
49 * @param functions precompiled code
50 * @param flags {@link ScriptFunctionData} flags
51 */
52 FinalScriptFunctionData(final String name, final int arity, final List<CompiledFunction> functions, final int flags) {
53 super(name, arity, flags);
54 code.addAll(functions);
55 assert !needsCallee();
56 }
57
58 /**
59 * Constructor - used from ScriptFunction. This assumes that we have code already for the
60 * method (typically a native method) and possibly specializations.
61 *
62 * @param name name
63 * @param mh method handle for generic version of method
64 * @param specs specializations
65 * @param flags {@link ScriptFunctionData} flags
66 */
67 FinalScriptFunctionData(final String name, final MethodHandle mh, final Specialization[] specs, final int flags) {
68 super(name, methodHandleArity(mh), flags);
69
70 addInvoker(mh);
71 if (specs != null) {
72 for (final Specialization spec : specs) {
73 addInvoker(spec.getMethodHandle(), spec);
74 }
75 }
76 }
77
78 @Override
79 String getDocumentationKey() {
80 return docKey;
81 }
82
83 @Override
84 void setDocumentationKey(final String docKey) {
85 this.docKey = docKey;
86 }
87
88 @Override
89 String getDocumentation() {
90 final String doc = docKey != null?
91 FunctionDocumentation.getDoc(docKey) : null;
92 return doc != null? doc : super.getDocumentation();
93 }
94
95 @Override
96 protected boolean needsCallee() {
97 final boolean needsCallee = code.getFirst().needsCallee();
98 assert allNeedCallee(needsCallee);
99 return needsCallee;
100 }
101
102 private boolean allNeedCallee(final boolean needCallee) {
103 for (final CompiledFunction inv : code) {
104 if(inv.needsCallee() != needCallee) {
105 return false;
106 }
107 }
108 return true;
109 }
110
111 @Override
112 CompiledFunction getBest(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden, final boolean linkLogicOkay) {
113 assert isValidCallSite(callSiteType) : callSiteType;
114
115 CompiledFunction best = null;
116 for (final CompiledFunction candidate: code) {
117 if (!linkLogicOkay && candidate.hasLinkLogic()) {
118 // Skip! Version with no link logic is desired, but this one has link logic!
119 continue;
120 }
121
122 if (!forbidden.contains(candidate) && candidate.betterThanFinal(best, callSiteType)) {
123 best = candidate;
124 }
125 }
126
127 return best;
128 }
129
130 @Override
131 MethodType getGenericType() {
132 // We need to ask the code for its generic type. We can't just rely on this function data's arity, as it's not
133 // actually correct for lots of built-ins. E.g. ECMAScript 5.1 section 15.5.3.2 prescribes that
134 // Script.fromCharCode([char0[, char1[, ...]]]) has a declared arity of 1 even though it's a variable arity
135 // method.
136 int max = 0;
137 for(final CompiledFunction fn: code) {
138 final MethodType t = fn.type();
139 if(ScriptFunctionData.isVarArg(t)) {
140 // 2 for (callee, this, args[])
141 return MethodType.genericMethodType(2, true);
142 }
143 final int paramCount = t.parameterCount() - (ScriptFunctionData.needsCallee(t) ? 1 : 0);
144 if(paramCount > max) {
145 max = paramCount;
146 }
147 }
148 // +1 for callee
149 return MethodType.genericMethodType(max + 1);
150 }
151
152 private CompiledFunction addInvoker(final MethodHandle mh, final Specialization specialization) {
153 assert !needsCallee(mh);
154
155 final CompiledFunction invoker;
156 if (isConstructor(mh)) {
157 // only nasgen constructors: (boolean, self, args) are subject to binding a boolean newObj. isConstructor
158 // is too conservative a check. However, isConstructor(mh) always implies isConstructor param
159 assert isConstructor();
160 invoker = CompiledFunction.createBuiltInConstructor(mh);
161 } else {
162 invoker = new CompiledFunction(mh, null, specialization);
163 }
164 code.add(invoker);
165
166 return invoker;
167 }
168
169 private CompiledFunction addInvoker(final MethodHandle mh) {
170 return addInvoker(mh, null);
171 }
172
173 private static int methodHandleArity(final MethodHandle mh) {
174 if (isVarArg(mh)) {
175 return MAX_ARITY;
176 }
177
178 //drop self, callee and boolean constructor flag to get real arity
179 return mh.type().parameterCount() - 1 - (needsCallee(mh) ? 1 : 0) - (isConstructor(mh) ? 1 : 0);
180 }
181
182 private static boolean isConstructor(final MethodHandle mh) {
183 return mh.type().parameterCount() >= 1 && mh.type().parameterType(0) == boolean.class;
184 }
185
186 }